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How video wall works

digital video wall technologies and delta rear projection video wall and best video wall controller
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VISUAL INTELLIGENCE FOR CRITICAL DECISIONS A CineMassive Technical White Paper A COMPARISON OF VIDEO WALL TECHNOLOGIES A Guide to Key Fea- tures and Benefits Issued April 2015 Release 1.0 CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANTA, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 Table of Contents Abstract 4 Introduction 5 Why A Video Wall? 5 Choosing a Video Wall Display 5 LCD Video Walls 6 How It Works 6 Characteristics and Performance 7 Visual Performance 7 Spatial, Environmental, and Aesthetic Concerns 8 Ease of Deployment 9 Reliability and Resilience 9 Cost of Ownership 10 Plasma Display Panel Video Walls 10 How It Works 10 A Technology in Decline 10 Projection Cube Video Walls 11 How It Works 11 Characteristics and Performance 12 Visual Performance 12 Spatial, Environmental, and Aesthetic Concerns 13 Ease of Deployment 13 Reliability and Resilience 14 Cost of Ownership 14 Blended Projection Video Walls 15 How It Works 15 Characteristics and Performance 17 Visual Performance 17 Spatial, Environmental, and Aesthetic Concerns 18 Ease of Deployment 19 Reliability and Resilience 19 Cost of Ownership 20 PAGE 2 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, A CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANT TLANTA, GA 30324 1.800.792.5975 WWW A, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COM .CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 Table of Contents, Cont. Emerging Technologies 20 Indoor Direct View LED 20 Direct View OLED 22 Laser Phosphor Display 22 Conclusions 24 Searching for the Ideal System 24 Concluding Thoughts 24 References 25 Disclaimer 27 PAGE 3 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, A CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANT TLANTA, GA 30324 1.800.792.5975 A, GA 30324 1.800.792.5975 WWW WWW.CINEMASSIVE.COM .CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 Selecting the ideal video wall solution can be bewildering. A complete video wall system requires ABSTRACT a number of components, and a wide range of options are available for each of them. Of all of the decisions that must be made when planning for a video wall system, perhaps the most deceptively simple is selecting the display type. An enormous range of video wall display technologies are available on the market today, each with their own unique characteristics, advantages, and disadvantages. Many potential buyers, architects, and engineers become quickly overwhelmed by the sheer variety of display types. Worse, manufacturers provide a plethora of promotional materials that often make conflicting claims and use widely inconsistent terminology and systems of measurement to describe their products. It is unsurprising that organizations often struggle to compare competing technologies or even to define CURVE, Georgia State University Library which characteristics are most valuable and relevant for them. This white paper aims to demystify the video wall display selection process by providing an unbiased guide to the most popular display technologies available today. It introduces four of the currently most popular display types and three emerging display technologies that may also merit consideration. Each display discussion provides a basic explanation of the technology behind the display type and describes some of the common advantages and disadvantages of that technology with regards to physical performance, aesthetics, maintenance, and cost of ownership. The information presented in this document has been collected from internal subject matter experts along with external sources, including industry research papers, dissertations, journals, and more. While the writers have made every effort to provide current, accurate, and useful information, it should be noted that individual products and user experiences will vary. In addition, video wall technology is advancing rapidly and the characteristics of a particular display type may shift over time. Ultimately, only the customer can determine the ideal video wall system for his or her own application and environment. The information that follows is simply intended as a framework to introduce available technologies and present considerations that may be useful in refining the selection process. PAGE 4 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANTA, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 Choosing a Video Wall Display INTRODUCTION The exploding popularity of video walls in recent years A video wall is a large-scale visual display consisting has generated an intensely competitive market and a of multiple monitors, projectors, or other display tech- large selection of video wall options. For many organi- nologies that are tiled or overlapped to form a sin- zations, it is an excellent, and even necessary, time to gle, expansive display surface. Today, video walls are invest in a video wall system. However, selecting the transforming the way people communicate, learn, and ideal video wall can be a confusing and overwhelming solve problems around the world. At their best, these task due to the enormous variety of display technolo- large-scale visual displays are engaging and powerful gies available in today’s market. An internet search for tools that enhance users’ ability to see, understand, and “video wall” yields a range of terms, including “LCD,” share information with others. “LED,” “LPD,” “cubes,” and “projectors,” to name only a few. Each of these terms represents a distinct type of display technology and even within each of these cate- Why A Video Wall? gories, there are a number of nuances and options. In many cases, video walls offer significant advantag- The materials provided by video wall manufacturers es over the use of a single, large display. Perhaps often claim that the display technology of their spe- most importantly, video walls can provide much larger, cialty is the ideal solution for any application. In reality, higher-resolution images than single displays. A large, however, every application is unique and each type of high-resolution central display enables all of the users display offers a distinct set of advantages and disad- in a space to clearly view, interact with, and share infor- vantages. A particular display type may be excellently mation. Teams can unite their resources on a central- suited to some activities and environments, but poorly ized platform and engage in collaborative monitoring, suited to others. In order to select the ideal video wall exploration, and problem-solving. Video walls can also for a particular application and environment, it is critical offer far more flexibility of shape and dimension than to first develop an understanding of the technology single displays. Video walls can be curved, non-rect- behind each display type, its inherent strengths and angular, or even three-dimensional. Far more versatile weaknesses, and the options available. than a single display, a video wall can function as an im- mersive research environment, a 3D simulation system, or even an element of architectural design. When integrated with effective processors and soft- ware, video walls can provide benefits for virtually any application and environment. Video wall systems can provide enormous advantages in control room environ- ments, from military command centers to utility control rooms and security operations centers. Functioning as large-scale, high-resolution dashboards, they can increase situational awareness, enhance collaboration, and facilitate agile incident response. In universities and research facilities, video walls enable the interactive ex- U.S. Army ploration of big data and research content and can dis- play high-resolution material at extraordinary scale and detail. In corporate boardrooms and conference rooms, video walls can provide engaging, interactive presenta- tion platforms and enhance unified communications. In public spaces, video walls can create visually stunning platforms for promotional media or public information boards for critical messages. PAGE 5 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANTA, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 Most LCD displays on the market today utilize TFT (thin-film-transistor) LCD technology, an active-matrix LCD VIDEO scheme in which each pixel is controlled by one to four transistors. The two major varieties of TFT LCD panels that are typically used in LCD video walls are TN WALLS (Twisted Nematic) and IPS (In-Plane Switching). These two technologies differ in the way that their liquid crystal molecules move in relationship to the panel plane. In TN panels, crystal molecules move parallel to the plane, while in IPS, they move perpendicular to it (Matuszczyk, 2000). This distinction creates a number of differences in the way that TN and IPS LCD displays perform and may be an important factor in selecting the ideal LCD video wall. The nuances of TN and IPS LCD performance will be further explored below. In full-array backlighting, common in early LED-LCDs, rows of LEDs were spread across the entire back panel of the display and divided into a number of zones that LCD Video Wall (CURVE, Georgia State University Library) were controlled individually by a local dimming feature, enabling portions of the backlight to be dimmed while others remained illuminated. This feature helped to improve contrast and black ratios in early LED-LCDs, How It Works but resulted in the displays being relatively thick and quite expensive (Wilcox, 2012). LCD is one of the most popular video wall technologies available today. LCD technology will already be Direct-lit (sometimes simply “backlit”) LED-LCDs were familiar to most due to its widespread use in personal developed as a more affordable alternative to expen- computer monitors and televisions. An LCD, or liquid- sive full-array displays. They feature fewer total LEDs crystal display, is a flat panel display that uses the light across the back of the display and some lack the local modulating properties of liquid crystals to display dimming function. Direct-lit displays are frequently an image. Each pixel of an LCD is composed of a even thicker than their full-array predecessors because layer of liquid crystal molecules aligned between two since fewer LEDs are used, they must be moved farther transparent electrodes and two polarizing filters. When back from the screen to provide the necessary light an electric field is applied, the liquid crystals twist or coverage. However, they are advantageous in terms reorient, allowing light to pass through and produce of brightness uniformity, and models that feature local images in color or monochrome (Matuszczyk, 2000). dimming offer excellent contrast ratios. Because liquid crystals do not emit their own light, Edge-lit LED-LCDs light the display from the edges LCD panels must utilize a backlight located at the back of the panel instead of the back. Light signals then of the LCD glass. CCFL (cold cathode fluorescent), transfer across the panel to display an image. Edge-lit an older backlighting technology, may still be used in LED-LCDs can be extremely thin compared to direct-lit laptop computer monitors. However, most of the large- models. However, they may lack the excellent bright- scale LCDs used in video walls are LED-backlit. In this ness uniformity and contrast levels of direct-lit displays system, LEDs (light emitting diodes) shine through the since the LEDs are not arranged evenly across the back liquid crystals to produce an image. An LCD video wall of the display (Wilcox, 2012). is built from an array of commercial-grade, narrow-bezel LCD panels that create a large-scale visual display. The individual panels used in LCD video walls typically measure from 42” to 60” diagonally. PAGE 6 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANTA, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 black regions appear greyish. However, this issue has Characteristics and Performance been improved significantly over the years. Current high-quality LCD displays, particularly IPS, can provide Visual Performance high contrast levels and deep blacks.   Resolution LCD video walls offer a number of advantages in Viewing Angle terms of visual performance. One major advantage is LCD technology can also offer extremely wide viewing resolution. LCD panels can provide some of the highest angles. IPS LCD panels provide a particularly excellent total resolutions of any technology available today, with viewing angle with minimal color and light drop-off, making most displays between 47 and 55 inches offering at images easier to see from a distance or from off-axis. least 1920x1080 (full HD) and some displays providing TN LCD displays provide a more limited viewing angle, resolutions as high as 3840x2160 (4K) or even 7680x4320 causing pixel colors to invert at extreme angles. This (8K). These ultra-high resolutions are made possible by makes IPS LCD a superior choice for large control room the high pixel density, or PPI (pixels per inch) that LCD environments in which many operators will need a clear technology can provide. view of the video wall. Due to its high pixel density, of LCD can produce a Appearance on Camera sharply detailed image that allows viewers to discern text When viewed on camera, older display technologies like and images with minimal eye fatigue. This high PPI also CRTs (cathode ray tubes) often appeared to flicker or show enables LCD video walls to be approached and viewed scan lines. This issue was caused by disparities between at extremely close proximity with no perceived loss of the refresh rates of the cameras and the refresh rates of image quality. On display types with lower PPI, text and the displayed images that the cameras were recapturing. images can be difficult to discern at close range. Because many older displays had fixed refresh rates, they could not be adjusted to match the cameras filming them. LCD video walls may be said to have a “stacked” However, most modern display technologies, including resolution as each additional panel increases the LCD, do not suffer from this issue because the refresh rate total resolution of the video wall. This represents a of the displays can be synched to the refresh rate of the significant advantage over projection-based systems, in camera. Therefore, LCDs appear solid and steady and do not which the projected image is simply stretched across a show scan lines or other artifacts when viewed on camera. larger surface, diminishing the pixel density.   Color Reproduction and Uniformity Brightness Regarding color reproduction, or how well colors can be Many LCD panels can provide high brightness, and accurately displayed, LCD video walls vary depending brightness levels can be adjusted quickly and easily. For this upon whether TN or IPS panels are used. Most TN panels reason, LCD is a popular display choice for environments only display 6-bits per RGB color, and as such can only with significant ambient light that would wash out a represent 70% (18 bits total) of the 24-bit color available projection-based display. Maximum LCD brightness from graphics cards. To compensate, TN panels display decreases gradually over time, but higher brightness interpolated 24-bit color by using dithering or Frame settings may be used to compensate for this if the displays Rate Control (FRC) adjacent pixels to create the missing were not initially running at their full brightness potential. desired shade (Artamonov, 2004). Due to using 8 bit or even 10 bit panels, professional IPS LCD displays have a much wider color gamut, enabling them to provide highly Contrast Ratios and Black Levels accurate color reproduction without dithering (although Early LCD displays were not able to provide the dithering may still be found on certain models). For this excellent contrast ratios and black levels available in reason, video walls that use IPS LCD panels may be the technologies like Direct View LED and plasma. This was preferred choice for marketing groups or any users that because some of the light produced by the backlight require excellent color reproduction. was still visible behind pixels that were fully off, making PAGE 7 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANTA, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 Color uniformity is typically excellent within individual is rarely considered a disadvantage for most video LCD panels, although color may initially need to be wall applications. TN and IPS technology once varied calibrated when a video wall is built to ensure precise significantly in response time, with TN LCDs having uniformity across multiple panels. While the brightness far faster response times than IPS LCDs. However, this of LCD panels will decline over time, color generally disparity has been reduced in recent years and there is remains consistent. This represents an advantage over now little practical difference in most use cases. projection-based systems, which may experience heavy color changes over time. Touch Interactivity LCD displays can be configured to provide multi- Visual Artifacts touch control, enabling users to interact directly with LCD displays may experience some minor issues display content. While most display technologies can with image retention, although they are not nearly as be modified for touch, LCD is unique in that touch can susceptible as plasma displays. In applications where typically be provided by the manufacturer, eliminating a static image is displayed for an extended period of the additional installation time and expense of a third- time, pixels may lose their ability to return to a relaxed party integration. Touch provides increased interactivity state. This image persistence is generally minor and and can be a valuable asset for presentation, research, temporary. and education applications. Dead and stuck pixels may also occur in LCD displays, Bezels typically due to transistor error. Stuck pixels may cause One frequently-cited disadvantage of LCD video walls is a single sub-pixel to appear “stuck” on a certain color, bezel width. Compared to projection cubes or blended while dead pixels may appear permanently white or projection systems, LCD panels have thicker bezels, black. Stuck pixels can sometimes be corrected by or seams, appearing around each panel in the array. software or physical methods, or may eventually correct For applications in which detailed charts or graphs are themselves. Dead pixels are more difficult to correct. displayed, bezels may be seen as disruptive. They may However, most LCD manufacturers will replace a display also diminish the effect of 3D content in virtual reality with a certain number of sub-pixel defects and some and simulation applications. In some cases, customers manufacturers have zero-tolerance policy for these may simply find them unattractive. defects. Dead or stuck pixels are generally a minor concern unless the video wall will be viewed at close However, LCD manufacturers are well aware of this proximity and such defects will be easily noticed. In complaint and have made significant progress in larger environments, individual pixel defects are rarely reducing bezel width with each new generation of noticeable during regular use.  display. Some current LCD displays offer bezel widths as low as 3.5mm, a dramatic reduction from previous 5mm Response Time and 7mm models. Response time, measured in milliseconds, is a measurement of the amount of time a pixel in a display takes to change. Displays with lower response times can Spatial, Environmental, and Aesthetic perform faster transitions and show fewer image artifacts. Concerns While response time for LCD has been improved significantly over the years, it is still somewhat slower Footprint than many competing technologies. The minimum Bezels aside, LCD video walls can offer a number of response time for the latest LCD displays is around aesthetic and spatial advantages. Perhaps the most 1 millisecond, while some DLP projectors offer evident of these is their minimal footprint. LCD video response times in the low microseconds. However, walls have an extremely shallow depth, which can be this distinction may be imperceptible to the human as narrow as 4” deep when wall-mounted. LCD video eye, so the response time of today’s LCD displays walls are extremely space-efficient when compared PAGE 8 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANTA, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 to projection cube systems, which require a minimum Scalability of 24” and cannot be wall-mounted, or blended rear LCD video walls are easily extensible over time, projection systems, which may take up 14’ or more and making them an excellent solution for organizations require their own rooms or enclosed spaces. with budget constraints that may want to expand their systems in the future. However, it is always recommended to plan for such expansions in Size and Shape advance, taking into account the increased spatial and LCD video walls offer a wide range of options in terms electrical requirements of an expanded system so as of size and shape. They are extremely scalable and to minimize construction later. In addition, because can be easily expanded by simply adding additional LCD displays are constantly being developed and LCD panels to the array. In addition, because of improved by manufacturers, it is advisable to undertake the narrow profile of LCD panels, a wide range of expansions as soon as possible in order to guarantee mounting options are available. LCD video walls can the availability of the original displays and minimize be freestanding, wall-mounted, recessed into a wall, or brightness discrepancies between the older displays even mobile. They can also be built on a curved radius and the new additions. to accommodate unusual architecture, save space, or create an immersive environment. Reliability and Resilience Ease of Deployment Reliability LCD video walls can provide extreme reliability and Weight are capable of 24/7 performance with no down-time LCD panels are easy to mount and align, and because needed. This gives LCD a tremendous advantage over little maintenance is necessary after installation, re- lamp-based projection systems, which require regular alignments are rare. However, while individual LCD system downtime to replace and cool lamps. displays are lightweight, total weight can become substantial depending on the size of the video wall. A The reliability of LCD technology is due in part to structural wall may be required to safely hold the weight the long lifespan of the LED light source and the of a large wall-mounted LCD video wall. Similarly, the absence of consumable parts that would need regular supports of large freestanding systems may need to be maintenance. Some premium LCD displays even offer mounted to the building structure for extra stability. redundant power supplies for each individual display, ensuring continuous operation even if a power supply is compromised. In addition, modern LED-LCD panels Location of Power Supplies generate relatively little heat, particularly in contrast to One variable affecting the installation of LCD video early CCFL-LCD and plasma panels. LCD displays that walls is the location of the power supplies. Displays use remote power are superior in this regard because using local power supplies may require electrical the power supplies are located away from the display additions or modifications to be made to the wall. panels, reducing heat levels. Displays with remote power supplies will require electrical circuits to be available at the equipment location. However, these circuits are frequently available Resilience, Serviceability, and Lifespan in a nearby data center or IT closet, making them less LCD video walls enjoy an extremely long lifespan, expensive to connect. Remote power supplies are also with some systems having an MTBF (mean time advantageous in that they reduce the depth of the between failures) of over 100,000 hours when used video wall, lower the thermal footprint of the system, 24/7 (CineMassive, 2014). Because LCDs are composed and enable easier serviceability than local power of solid-state electronics with no moving parts, they supplies. are very resilient to environmental stressors such as vibration, humidity, UV light, and rugged landscapes, and can be easily transported with minimal risk. PAGE 9 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANTA, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 If they are mounted properly, LCD panels are quick and easy to service. Some models even include replaceable PLASMA DISPLAY modular electronics, enabling certain components to be replaced without replacing the entire panel. The resilience and easy serviceability of LCD video walls PANEL VIDEO makes LCD an excellent solution for mobile displays and rugged, sub-optimal environments. WALLS Cost of Ownership How It Works Initial Cost Plasma display panels (PDP) are a flat panel display The initial cost of LCD video walls is moderate. They technology that uses small cells containing electrically are generally much less expensive than projection charged ionized gases, or plasmas, to produce an cubes and rear blended projection systems, while image. A plasma display consists of millions of tiny initially more expensive than traditional front projection gas-filled compartments, or cells, between two panels systems. The main economic advantage of LCD video of glass. walls is in their low total cost of ownership (TCO). PDPs produce an image by applying high voltage to trigger a series of reactions in the gas-filled cells. Total Cost of Ownership When voltage is applied to a cell, the gas inside forms As previously discussed, LCD systems include a plasma, causing a reaction that increases the energy no consumable parts and do not require regular level of the atoms until that excess energy is shed maintenance, both factors that make traditional front as ultraviolet photons. The UV photons then strike projection and blended projection systems costly to phosphor molecules that are painted on the inside maintain over time. LED-LCD displays have a much of the cell, resulting in a second reaction that causes lower power consumption than many competing the phosphor molecules to shed a photon at a lower technologies, particularly when compared to projection, energy level than the UV light. This energy is shed plasma, and legacy CCFL-LCD systems. With minimal mainly as infrared heat, but also produces some visible maintenance requirements, low power consumption, light. Different phosphors are employed to produce and a typical lifespan of around 6.8 years to half- various colors of light and each pixel is comprised of brightness, LCD video walls offer an extremely low total three cells to provide the primary colors of visible light. cost of ownership and are one of the most affordable Varying the voltage of the signals applied to these cells video wall options in the long term. results in different visible colors. Like LCD video walls, plasma video walls are built from an array of multiple plasma panels (Harris, 2000).   A Technology in Decline When plasma technology entered the mainstream display market in the mid-1990s, it offered a number of advantages over the CCFL-LCD and CRT (cathode ray tube) displays of the time. Plasma provided larger screen sizes than traditional tube TVs and ushered in an era of wide format, high-definition displays. Although plasma displays were still somewhat heavy, they were lighter and thinner than comparable CRTs at the time. Plasma also provided superior contrast ratios, viewing PAGE 10 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANTA, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 angles, and response times when compared to many early CCFL-LCD displays. This excellent image quality PROJECTION along with the availability of displays up to and over 100” enabled plasma to enjoy broad popularity, particularly in the television and home cinema markets, CUBE VIDEO for some time. Throughout the years, however, plasma has continued WALLS to suffer from some significant disadvantages. Perhaps the most widely-recognized of these issues is image retention. When a static image is displayed for some time, phosphors in the cells overheat, losing their luminosity and producing permanent “shadows” that persist even with the power off. In addition, when very bright images are displayed, pixels may build up a charge, producing “ghost images” that linger temporarily on the display. Plasma also consumes far more power and gives off much more heat than LCD, particularly when displaying bright content. In the mid-2000s, as the thinner and lighter LCD technology began to see significant improvements in contrast ratio, viewing angles, and response times, plasma gradually lost market share. Eventually, plasma’s Projection Cube Video Wall advantages over LCD were minimized and could no longer outweigh the issues of screen retention and How It Works power usage. In addition, the price of plasma displays failed to decrease as rapidly as LCD prices throughout the 2000s. At the time of this writing, most major Like LCD, projection cubes are a popular variety of manufacturers no longer produce plasma displays, and video wall technology. Projection cubes consist of a while some existing inventory may still be available, rear projection system that is housed in a sealed cube the technology is rapidly becoming obsolete. Because to increase contrast levels and limit ambient light from plasma technology is vanishing quickly and may not be washing out the projected image. In a projection cube supported much longer, it is not recommended as a system, images are produced by projecting light onto video wall solution. a mirror that then reflects the image onto a screen for viewing. While legacy projection systems used lamps as a light source, most contemporary projection cubes employ LED backlighting. The adoption of LED backlighting has reduced maintenance requirements, eliminated expensive consumable parts, and lowered operating temperatures, making projection cubes a much more competitive and versatile option than they were previously. Projection cube video walls are constructed from a series of projection cubes that are stacked on top of each other. Individual cube sizes vary widely. While most cubes currently measure between 50” and 80” diagonally, some cubes may be as small as 20”. PAGE 11 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANTA, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 While not altogether seamless, projection cubes feature Brightness extremely narrow bezels, enabling cube-based video The sealed casing of projection cubes limits the effects walls to appear virtually seamless from a typical viewing of ambient light and increases contrast levels, enabling distances. For this reason, projection cube video walls cubes to produce images that are easier to discern may be chosen for applications that require a near- and cause less eye fatigue than most standard front seamless display, but demand more reliable performance projection systems. However, projection cubes cannot than traditional projection-based systems can offer. provide as much brightness as LCD or Direct View LED technologies. Therefore, some ambient light control is generally required to ensure that display content is clearly visible. While projection cube video walls appear Characteristics and Performance steady and solid on camera, the need for lower ambient light levels may affect photography and filming. Much Visual performance like LCDs, projection cubes gradually lose brightness over time as the LED light engine ages. Near-Seamlessness From a visual perspective, the key distinguishing characteristic of projection cube video walls is their Viewing Angle near-seamless appearance. With bezels as narrow as The viewing angle of projection cubes is lower than 0.2 mm or less between screen surfaces as large as that of competing technologies like LCD, LED, and 80” (2032 mm) diagonally, a projection cube video LPD. This is because projection screens focus light wall can appear to be virtually seamless. Projection toward the on-axis viewer, so viewers located at wider cube technology is therefore an excellent solution for angles experience drastic light fall-off and color applications in which more perceptible bezels could uniformity issues. Due to this limitation, projection cube compromise display content and distract viewers. technology may not be ideal for environments where viewers will be distributed across a wide viewing area. Resolution The resolution of projection cube technology varies, but Color Uniformity can be relatively high. Like LCD video walls, projection Like LCD displays, individual projection cubes have cube video walls have a “stackable” resolution, excellent color uniformity but a projection cube video meaning that the total resolution of the video wall wall will need to be calibrated during assembly to is increased with each additional cube. A number of ensure uniformity across all of the cubes. Some cube different aspect ratios are available, including 4:3, technologies feature auto calibration which reduces the 16:9, and 16:10. Typical resolutions include 1024x768 ongoing need to calibrate displays. DLP-LED projection (XGA), 1400x1050 (SXGA+), 1920x1080 (Full HD), and cubes experience no image retention issues and are 1920x1200 (WUXGA). preferable to emissive technologies for displaying static images over extended periods of time. Projection cubes can provide higher total resolutions than some other technologies, such as direct view LED and LPD. Compared to LCD or plasma systems however, Refresh Rates projection cube systems have a lower pixel density, Refresh rates for rear projection cubes are typically so larger displays must be used to create a video wall comparable to those of LCD displays of similar canvas of a certain resolution. For example, an 80” 1080P resolutions (Mitsubishi, 2014). Expressed with a frequency projection cube is comparable in height to two stacked rating of Hertz (Hz), refresh rates indicate the number 47” 1080P LCD panels, but provides only half the vertical of times the screen redraws or refreshes to form a fluid resolution of the LCD panels. This reduced resolution video image. Refresh rates may also be expressed as and increased pixel spacing may not be an issue if the scanning frequency per the given resolution, i.e. 60Hz at video wall will be viewed from some distance. However, if 1920x1080, or simply listed alone as a maximum rate, i.e. viewers will be seated in close proximity or will be able to 120Hz Refresh. walk up to the wall, this factor may be of more concern during the system design. PAGE 12 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANTA, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 In cases when only the maximum refresh rate is listed, Like LCD panels, projection cubes are tileable, and if additional research may be necessary to determine large cubes are used, they can be a more cost-effective whether the display will accept the intended input solution than LCD for very large video walls. The large resolution and frequency. Typically, displays are also dimensions of each cube allow a large video wall to be capable of displaying lower resolution and refresh rate built using fewer individual cubes, although the weight standard combinations than the specified maximum. of the cubes places certain limitations on the number of If only the full pixel clock rate is listed, it will be necessary cubes that can be stacked on top of each other.   to calculate the pixel clock or bandwidth for the intended input. A basic formula may be used to determine this information: (Horizontal Pixels + Horizontal Blanking) x Footprint (Vertical Pixels + Vertical Blanking) x Desired Refresh Rate Compared to flat panel technologies like LCD, cube = Total Pixel Clock. For example, if the desired input was video walls have a large footprint. Most cubes are at least a PC with a 1600x1200 image at 60Hz, the formula would 24” deep, and because of their weight must be mounted appear as (1600+560) x (1200+50) x 60 = 162MHz. The on the floor or on a solid platform. In addition, most result, 162MHz, represents the total pixel clock capability basic cube models are rear-serviceable, necessitating that the display would need to show the image. Online additional floor space to provide technicians with rear calculators are also available to perform this calculation. access to the cubes. Upgraded models may offer front- serviceability, which reduces floor space requirements If refresh rate information is not presented clearly, it is but adds to the initial price of the cubes. always advised to contact the display manufacturer for further clarification. Ease of Deployment Touch Interactivity Unlike LCD displays, projection cubes do not typically Weight offer touch interactivity as a factory option. A projection Cube-based video walls require a significant amount of cube video wall can be configured for touch after assembly during implementation as compared to LCD assembly, but this typically requires the use of rear- or other emissive technologies. Because fully assembled serviceable cubes, which demand more floor-space cubes are both heavy and fragile, the projectors, screens, for serviceability. In this case, a glass substrate can be cabinets, and light engines for each cube are typically permanently installed in front of the cube wall. For shipped separately to the building site and cubes are video walls composed of front-serviceable cubes, the assembled on-site during the construction of the video sheet of glass required for touch must be removable so wall. While quite heavy, projection cubes provide the as to not inhibit serviceability. In either arrangement, advantage of an in-built mounting system, since cubes the addition of a touch system to a cube video wall can simply be stacked on top of one another. This adds significant complexity and cost. For projects in represents an advantage over LCD panels, which require which touch interactivity is a major focus, LCD displays an external mounting frame or wall. may be a more practical and cost-effective option.   Scalability Like LCD video walls, LED-based projection cubes are scalable over time, enabling customers to expand Spatial, Environmental, and Aesthetic their systems after initial implementation. As with all Concerns scalable systems however, it is advised to consider any plans for future expansion when designing the video Size and Shape wall environment so that an expanded system can be Projection cubes offer an excellent range of options in accommodated in the space. It is also recommended terms of shape and size. Cube video walls can be flat, to implement desired expansions as soon as possible in curved, and even non-rectangular in shape, and the order to guarantee parts availability and consistency in broad range of aspect ratios and cube sizes that are brightness. available increase these options further. PAGE 13 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANTA, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 Reliability and Resilience Cost of Ownership Reliability Initial Cost Today’s LED-based rear projection cubes offer very In most cases, the initial cost of a projection cube high reliability, particularly in contrast to lamp-based video wall is significantly higher than some competing cubes or projection systems. Like LED-LCD video walls, technologies. A small to medium LED-based cube LED-based cube walls can provide 24/7 performance wall may be around three times the price of an LED- and are suitable for use in critical control room LCD video wall of similar dimensions. However, for environments. Because LED-backlit cubes do not rely very large-scale video walls, projection cubes may be upon consumable parts like lamps, they require no a less-expensive option than LCD, particularly if large regular maintenance or downtime. In addition, internal individual cubes are used. fans or water pump cooling systems help ensure that operational temperatures are kept within optimal thresholds, increasing the lifespan of the system. Total Cost of Ownership Long-term cost of maintenance for LED-based cubes is minimal, although, as discussed previously, screens Resilience, Serviceability, and Lifespan may occasionally need to be replaced. The power LED-based cube video walls can have a very long consumption of LED-based projection cubes is similar lifespan, typically ranging from 60,000 to 100,000 MTBF to that of LED-LCD systems. While LED-based cubes (Mitsubishi, 2014). After implementation, LED-based require more power than lamp-based projection cubes require minimal maintenance. However, the systems to produce an image of the same size, lamp- presence of moving parts within each cube places this based systems generate far lower resolutions. In order technology at a slight disadvantage against technology to produce an image at the same resolutions as an like LED-LCD, which is composed entirely from solid- LED-based projection system, a lamp-based system state electronics, and thus includes fewer potential would require multiple blended projectors, and would points of failure. In LED projection cubes, screens are ultimately draw more power. Therefore, if high-resolution the most common component to require maintenance output is required, LED-based projection cubes are as they can be damaged easily if impacted and may be a more energy-efficient solution than lamp-based prone to peeling over time. More rarely, a light engine projection systems. or fan may need to be replaced. If maintenance is required for a cube, most components can be replaced Overall, while the initial price of LED-based cubes with minimal downtime and without requiring the entire is quite high, their minimal maintenance, low power cube to be removed. As discussed above, the method consumption, and long lifespans lower the total cost of of serviceability varies depending upon whether the ownership, making them a far more economical solution cubes are rear-serviceable or front-serviceable. than lamp-based projection systems in the long term. Total cost of ownership is still higher than LED-LCD While extremely reliable within most climate-controlled, systems, but the near-seamlessness of cube video walls indoor environments, projection cube video walls may justify this additional expense for some customers. lack the environmental resilience of LCD video walls. Although LED-backlit cubes are less fragile than lamp- based projection systems, they still contain a number of moving parts and cannot withstand a great deal of vibration or instability. They are also sensitive to high levels of humidity and heat, which may cause screen damage and peeling over time. The need for a stable, controlled environment along with the sheer size and weight of each cube make a cube-based video wall an unlikely candidate for use in rugged, temporary, or sub- optimal environments. LED Projection Cube PAGE 14 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANTA, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 onto mirrors that then reflect it onto the screen. This latter arrangement “folds” the image, doubling the BLENDED throw ratio of the projectors so that the desired image size can be produced from half the distance, and the projection room can be smaller. The projection room PROJECTION functions much like a projection cube in controlling light levels on the screen. By minimizing ambient light, VIDEO WALLS rear projection systems can produce high contrast ratios and bright images, so they generally do not require projectors as bright or as costly as those needed for front projection systems. Another advantage of rear projection is that the projection room prevents much of the heat and noise generated by the system from entering the viewing environment. In front blended projection, projectors are mounted from the ceiling or wall in front of a screen surface and light is reflected off of the screen. This method requires much less space than rear projection and is typically selected when there is insufficient room available to house a rear projection system. Brighter, more expensive projectors may be required for front projection because of the presence of ambient light in Blended Projection Video Wall the space. However, front projection arrangements are typically still less expensive overall than rear projection systems due to the less costly screens and mounting How It Works systems that can be used. Similar to projection cubes, but on a larger scale, blended Projectors used for blended projection video walls projection video walls combine two or more projectors typically employ one of three types of light sources: in order to produce an image that is larger or higher- lamps, LEDs, or laser. Each light source has unique resolution than could be generated by a single projector. advantages. Traditional lamp-lit projectors can be Blended projection systems are able to display high- extremely bright, making them well-suited for front resolution images on a completely seamless surface of projection systems. However, lamps will need to virtually any size and shape. This unique capability makes be replaced about twice a year and are expensive, blended projection a popular choice for simulation and leading to high operating costs. LED-backlit projectors training, virtual environments, and other applications eliminate the maintenance issues caused by lamps, but requiring hyper-realistic or immersive effects. cannot provide the same levels of brightness. Thus, LED-based projectors may be a preferable choice for In a blended projection system, multiple projected rear-projection systems, but current models are not yet images are overlapped and their edges are gradually bright enough to be ideal for front-projection. Laser cross-faded or dithered to produce a single, seamless projectors, a relatively new technology, can provide image. Most blended projection systems require some brightness levels comparable to many lamp-based amount of external processing to blend and warp the systems. Although not as bright as the brightest lamp- image, but some premium projectors have most of based projectors, their high contrast levels may make these functions built-in. Blended projection systems them appear nearly as bright. With no consumable may be designed with either rear or front projection. parts, laser projectors also provide far lower operating costs and maintenance requirements than lamp-lit In a rear blended projection system, the projectors are projectors (Digital Projection, 2012). located behind the screen, typically in an enclosed rear projection room. The projectors may either project light directly onto the screen, or may project light PAGE 15 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANTA, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 Projectors also vary in their imaging technology. a fixed supporting frame and permanently mounted to DLP and LCD are the most common types of image the wall. The framing device applies uniform tension production technology currently available for to the screen surface to keep the surface taut. Front commercial projects (Morrison, 2013). LCoS (liquid projection systems occasionally use rigid glass or acrylic crystal on silicon) projectors, while popular in the screens, but this is generally not necessary unless the consumer market, are typically too small to be used system is located in a busy public space and must be for commercial video wall projects. DLP and LCD each particularly robust. The most common screen solution offer unique advantages and disadvantages. However, for rear projection systems is a rigid, frame-mounted it is worth noting that these technologies are in glass or acrylic screen with a layer of projection film constant development, so the characteristic strengths bonded to the surface. These rigid screens provide and weaknesses of each may shift over time. uniform flatness and minimize image distortion. Fabric screens are also available for rear-projection, but DLP (digital light processing) projectors use tiny mirrors are rarely used outside of mobile applications like to reflect light toward or away from the screen. To production staging. create color, most models use spinning color wheels with color filters. Some premium DLP projectors use Both front and rear projection screens use a rating three DLP color chips instead of a color wheel. DLP system called screen gain, or focus, that provides projectors can provide extremely low response times, in specifications about the screen’s visual performance. some cases in the low microseconds. This enables them Gain is the measurement of the amount of light to provide greater sharpness and detail for fast motion reflected off of the screen (in front projection) or passed images than LCD projectors. DLP also often provides through the screen (in rear projection) to the viewers superior contrast ratios and black levels compared to in the space. In this system, a screen gain of 1.0 is a those produced by LCD projection. In addition, models “flat reflection,” or the amount of light reflected by a with color wheels may produce an artifact called a standard white board. “rainbow effect” in which bright objects appear to have a trail of rainbow light when moving rapidly across Screens with a gain higher than 1.0 reflect more than a dark surface (Morrison, 2013). This artifact is not this standard amount of light, increasing brightness perceptible at all to some viewers, but others may find by focusing the light directly at the viewer. High-gain it distracting. LCD projectors use three liquid crystal screens can help enhance the perceived brightness of panels which each create an image using just one smaller, less-costly projectors. However, this brightness primary color (red, green, or blue). The three images comes at the cost of the viewing angle, which must be are projected simultaneously to produce a full-color reduced to focus the light. Thus, higher-gain screens image. Due to their use of LCD panels, these projectors are best-suited to narrower spaces where the reduced frequently cannot provide the excellent contrast ratios viewing angle is not noticeable. High-gain screens may and black levels available from DLP projectors and may also suffer from hot-spots, or regions near the center of suffer from dead pixels. In addition, LCD projectors are the screen that are brighter than others. Hot-spots are susceptible to motion blur when displaying fast motion especially a concern in blended projection systems. content (Morrison, 2013). This may not be noticeable to some viewers, but may bother others. Because Screens with a gain of 1.0 or lower provide little to they use emissive, rather than reflective, technology, no focusing or redirecting of light back to the viewer. LCD projectors may also produce a more visible pixel Often produced in darker colors, these low-gain structure than DLP, creating a “screen door” effect. screens can produce superior contrast ratios and black (“DLP vs. LCD vs. LCOS,” 2014). levels than those produced by high-gain screens. In addition, their even distribution of light enables Another variable in blended projection systems is wider viewing angles and produces a more uniform screen technology. Depending upon whether front brightness, reducing the risk of hot spots. For these or rear projection is used, different materials and reasons, lower-gain screens are often recommended arrangements may be used for the projection screen. above high-gain screens for blended projection The most common screen solution for front projection systems. systems is a lightweight, flexible fabric stretched over PAGE 16 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANTA, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 Image Sharpness Characteristics and Performance There are a number of variables that affect perceived image sharpness in a blended projection system. Because sharpness is largely determined by resolution, Visual Performance the number and resolution of the individual projectors in the system has a large effect. The make and model Absolute Seamlessness of the projectors, lens type, and precision of lens The most striking visual characteristic of blended focusing during the installation process will also have a projection video walls is their absolute seamlessness. significant effect. In addition, as previously discussed, Competing technologies like LCD panels and cubes projectors using DLP imaging technology generally require multiple displays to be tiled together to create provide superior sharpness and detail for fast motion a video wall, which inevitably produces a seamed video than LCD projectors. Finally, the amount of display surface (however narrow the seams may be). processing required to optimize the image may also In a blended projection system however, the size and have an effect on image sharpness. Systems with flat resolution of the display surface depends only upon the projection surfaces produce the sharpest projected type and number of projectors used, so a single video image because minimal correction and processing is wall may, in theory, be as large as desired. needed to produce the image. If a curved projection surface is used, or if the projectors are simply poorly placed, the pixels must be manipulated to compensate, Resolution altering the image from its raw format and reducing The combination of multiple projectors enables the perceived sharpness. While this may be acceptable blended projection systems to produce far higher for general viewing, it is not ideal for applications like resolutions than single-projector systems. However, marketing or branding, where sharpness, image shape, when compared to LCD or projection cube video walls and uniformity are a primary concern. of similar dimensions, blended projection video walls typically have lower-resolutions. One reason for this is Image Brightness that when multiple projected images are blended, 10 to As with sharpness, the perceived brightness of 20% of the image is lost in the overlapping blend area, blended projection systems depends upon a number lowering the overall resolution to less than the total of factors. The size, light source, and screen type of combined resolution of the independent projectors. the projectors may all have an effect on brightness. The distance between the projectors and the screen In addition, the resolution of blended projection is also an important factor; brightness will decrease systems may be limited due to the sheer number as the projectors are moved farther from the screen. of projectors that would be required to yield the Ambient light in the environment will affect brightness same resolutions produced by tiled display systems. as well. While all blended projection systems require Traditionally, in order to produce resolutions similar to some amount of ambient light control, front projection a 4x4 array of 1080P LCD panels, a blended projection systems are particularly vulnerable to being washed system would have to use sixteen 1080P projectors. out by ambient light and may require particularly bright Such a system would be prohibitively expensive for projectors to produce sufficient contrast ratios. most customers, both initially and over time due to the ongoing costs of the consumable parts. In recent Viewing Angle years, the availability of 4K projectors has increased the Viewing angles for blended projection systems will vary practicality of large, high-resolution blended projection depending on the material and shape of the projection systems. If 4K projectors were used in the scenario surface. Please refer back to the discussion of screen described above, only four projectors would be needed materials for a more in-depth discussion of how screen to produce resolutions similar to the 4x4 LCD array. technology affects viewing angles. In general, however, However, the projector mounting system and ongoing the viewing angles produced by blended projection are maintenance for multiple 4K projectors may still be too quite narrow and brightness levels drop off sharply as costly for many customers. As 4K and 8K LCD displays the viewer moves off-axis. are now being released, LCD will likely remain a better value than blended projection in terms of resolution. PAGE 17 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANTA, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 Color Reproduction and Uniformity Spatial, Environmental, and Aesthetic Blended projection video walls can provide fairly high- Concerns quality color reproduction, but are typically unable to produce the extended color gamut provided by Size and Shape LCD displays and LED-based cubes. Both LCD and One of the major advantages of blended projection DLP projector types may eventually lose color and systems is their ability to project images onto a brightness uniformity over time. LCD projectors may surface of virtually any shape and size. With additional suffer from gradual degradation of the LCD panels, image mapping software and processing, projectors manifesting in dead pixels and unevenness. In DLP can produce images on curved, angular, or spherical projectors with color wheels, the color wheel may surfaces. The additional processing required to blend collect dust or degrade over time and bearings may multiple images and warp content for display on a non- wear and affect the rotation of the wheel, impacting standard surface may be provided externally or by the color uniformity and occasionally producing screen projectors themselves. Blended projection systems can artifacts. Finally, if lamp-lit projectors are used, the also produce extremely large images, although very lamps will dim at differing rates, resulting in gradual bright projectors must be employed to accomplish this, loss of uniformity until all of the lamps are replaced at resulting in a higher up-front cost. once. Due to these issues, blended projection systems may not be ideal for applications that require exact color reproduction and uniformity. Footprint The space consumed by a blended projection system varies dramatically depending upon whether the system Response Time uses rear or front projection. Rear blended projection Depending on the projectors used, some blended systems have a very large footprint, typically requiring projection systems can provide extremely fast response up to 14 feet or more of enclosed floor space to house times and refresh rates. As mentioned previously, the projectors. In many cases, mirrors are used to “fold” some DLP projectors offer response times in the low the image, doubling the throw ratio of the projectors so microseconds and combined refresh rates as fast as that the desired image size can be produced from half 120Hz or more, making them faster than LCD displays. the distance. The speed, advanced internal processing, and the seamlessness of blended projection systems makes Front blended projection is one of the most space- them an excellent option for displaying 3D content. efficient display technologies available. Projectors are mounted to the ceiling or wall, and the display screen is usually quite thin and can be wall mounted. Thus, Touch Interactivity the only floor space required is the space between the Like cube-based systems, rear blended projection projectors and the screen, which must be kept clear to video walls can be modified for smooth and seamless prevent shadows from being cast on the screen. touch interaction. This can be achieved by integrating special glass screens with an in-built touch sensor. Heat and Noise However, this modification is not recommended for One environmental disadvantage of blended projection front projection systems, since in this arrangement, the systems is the heat and noise that they produce. user would need to step between the projector and the Most large projectors give off a significant amount of screen to contact the wall, casting shadows and partially heat and their internal fan systems can be quite loud. blocking the projected image. Naturally, heat and noise levels are multiplied when several projectors are used together in the same space. This issue is more noticeable with front projection systems because the projectors are located in the same room as the users. Projector cases with cooling systems and air silencers may be integrated to reduce the heat and noise in front projection systems. PAGE 18 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANTA, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 Heat and sound issues are minimized in rear projection Reliability and Resilience arrangements as the projectors are generally housed in a separate, enclosed space. However, care should Reliability still be taken to ensure that sufficient cooling systems The overall reliability of blended projection systems is are in place in the rear projection room because typically lower than LCD or projection cube solutions. an excessively hot environment can reduce system In general, this technology requires more monitoring, lifespan. maintenance, and part replacement than competing technologies to maintain optimal performance. One issue is that blended projection systems rely upon light sources that require either regular service or Ease of Deployment replacement. In lamp-backlit projectors, lamps burn out and typically must be replaced about twice a year with Weight and Complexity moderate to heavy usage. In LED-backlit projectors, The ease of implementation for blended projection LED light engines usually require replacement within systems depends largely upon whether front or rear three to five years. The laser light source in laser- projection is used. The glass or acrylic screens used in backlit projectors will need to be replaced after about rear projection systems are heavier than front projection two years. Color and brightness uniformity will also screens, and rear blended projection systems may decrease as projectors age, causing image quality to involve a more complex implementation process suffer if key components are not replaced regularly. As if mirrors are used. However, when maintenance is previously discussed, large projectors may also produce required, rear projection systems are relatively easy a great deal of heat, which can accelerate system wear to service because their components are closer to the over time. ground and more accessible. Front blended projection systems may be easier to Resilience, Serviceability, and Lifespan install initially because screen materials are much In terms of environmental resilience, blended projection lighter. However, if projectors are mounted on high systems are often more fragile than competing ceilings, installers may need to use ladders or a lift to technologies, even within normal, climate-controlled install them, increasing the difficulty and expense of the environments. Image stability is very sensitive to installation. High ceiling-mounted projectors will also vibration, a vulnerability that is particularly severe in require a more complicated maintenance process, and systems in which the projectors are located far from the space may be unusable while maintenance is being the screen. Over time, environmental vibrations can performed. also cause projector lenses to drift out of alignment, impacting image sharpness. Vibrations can also cause moving parts to rub together, producing heat Scalability and accelerating wear and tear. Because of these When compared to tiled systems like LCD and vulnerabilities, it is critical to be aware of any vibration- projection cube video walls, blended projection producing equipment nearby and plan projector systems are not easily scalable over time. To enlarge a placement accordingly. blended projection system, significant changes must be made to projector placement and lens alignment. Most blended projection systems are not well-suited In some cases, additional projectors may be integrated for transport. However, some manufacturers offer into the existing system, but in many scenarios, the road-ready projectors for use in event production and projectors will need to be replaced completely. This trade shows. These travel-friendly projectors can be is especially likely if the current projectors are several packed into cases and projection screens can be simply years old. A new, larger screen will also need to be rolled up for transport. However, this mobile concept implemented to achieve an expanded image. Overall, is more practical for single projection than for blended the expansion of a blended projection system is likely projection systems. If multiple projectors are to be used, to be costly and labor-intensive. painstaking mounting and lens positioning will always be required to achieve the correct blending effect. PAGE 19 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANTA, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COMA COMPARISON OF VIDEO WALL DISPLAYS / APRIL 2015 / RELEASE 1.0 Due to this complex assembly process and the high price-point of travel-friendly projectors, mobile blended EMERGING projection systems are rarely used outside of large- scale, production-level event staging. TECHNOLOGIES While system lifespans vary depending on the individual components used, blended projection New video wall technologies are being developed and systems typically have significantly shorter lifespans refined every day. While these new technologies may than LCD and cube video walls. The need for regular spend years in development, once on the market, they maintenance downtime and part replacement may bar may quickly become popular or even disruptive. At the blended projection from environments where reliable time of this writing, three of the most exciting emerging 24/7 performance is critical. In other environments video wall technologies are direct view LED, OLED, and however, these issues may be less of a deterrent. Laser Phosphor Display. Because these technologies are relatively new, some Cost of Ownership aspects of their performance have not yet been thoroughly tested in the video wall industry. However, Initial Cost it is possible to make some preliminary assessments of The initial price of blended projection systems the strengths, weaknesses, and long-term potential of is typically lower than the price of LCD or LED- these emerging solutions. based cube systems of similar dimensions except when complex mirror systems are used. After six to twelve months however, the price of regular system maintenance and replacement parts causes the total Indoor Direct View LED cost of ownership to increase significantly. Generally speaking, direct view LED is not a new Total Cost of Ownership technology. It has long been the standard display Light source replacement is a major expense technology used in large outdoor billboards and contributing to total cost of ownership. Lamps may scoreboards as well as simple indoor signage like cost thousands of dollars and must be replaced about “open” and “exit” signs. In a direct view LED display, twice a year. Lasers and LED light engines are also very an array of LEDs is mounted on a flat panel and the expensive and typically require replacement within LEDs themselves produce the visual display. This two years and three to five years, respectively. Other represents an important distinction from LED-backlit system components like filters, fans, and color wheels technologies like LCDs and rear projection cubes, since may require service or replacement around twice a in those systems, the LEDs serve as a light source only year. Thus, when replacement parts and maintenance and do not produce images on their own. labor are considered, the long-term cost of blended projection systems may be significantly higher than that In direct view LED displays, a particular voltage is of LCD and cube-based video walls. applied to the leads of the LEDs, causing electrons to recombine with electron holes within the device and Blended projection systems can also draw a larger release energy, producing colored light. The color of amount of power than some competing technologies. the light produced is determined by the energy band While they may require less power than LCD or cube gap of the semiconductor in the LEDs. Full-color pixels systems to display an image of comparable size, are formed by clusters of red, green, and blue LEDs. blended projection systems require far more power to In some cases, white and yellow LEDs may also be produce an image of comparable resolution. Therefore, incorporated (LED, 2014). blended projection may not be an energy-efficient solution for applications that require high resolutions. PAGE 20 OF 28 CINEMASSIVE 150 OTTLEY DRIVE NE, ATLANTA, GA 30324 1.800.792.5975 WWW.CINEMASSIVE.COM