The benefits of Slim DLP - Embedded.com

The benefits of Slim DLP

Introduction
High definition television is all the rage today in the video realm of consumer electronics. In the U.S. the availability of High Definition television broadcasts, which is becoming more prevalent day by day, has brought a surge in consumer interest in newer televisions that can receive and display the higher quality video signals. But it is not just the video signals themselves that are changing consumer's habits, but the technologies behind the new high definition displays are rapidly advancing as well, providing consumers much improved styling, space efficiency and image quality than was available in the CRT display era of the past. High definition TV's using Texas Instruments' DLP' display technology has proven popular with many customers around the world in the past few years; however, as the average HDTV screen size continues to increase each year, solutions must be found to manage the cost, weight, power and overall styling of these TV's.

With slim DLP technology that Texas Instruments' DLP TV group has pioneered in the past year, DLP televisions have the potential to simultaneously address increased image quality and sleeker styling at larger size screens while keeping costs down and ease of use for consumers up. DLP TV has entered a new era of TV design with its slim line of TV models, drastically changing the cabinet styling as well as image quality. This article will address some of the key features of slim DLP TV technology.

Redefining the DLP HDTV
Slim DLP TV technology began with several goals in mind. Various prototype designs were generated and tested using focus groups and two distinct types of consumers were found, those that wanted to hang the TV on the wall, a small minority, and those that wanted to incorporate the TV into the furniture dcor of their household. This second group preferred a slim TV, not necessarily flat. The winning design was approximately 10″ deep, considerably thicker than flat panel TVs but considered thin enough. Thus was targeted the main goal to reduce the overall depth of a standard DLP television by up to 30%, a target that, if reached would allow a 50″ DLP TV to be thinner than a 40″ plasma or LCD TV on a stand. Lighter weight and stability were surprisingly important considerations for many consumers. But the reduction in DLP TV cabinet depth and weight also had to be balanced with regards to system cost while also allowing for increased modularity of components to maximize cost effectiveness at the light engine level. Wide variety was found in the desired placement of the TV in the home, and so support for many installation options was considered just as important as getting to “thin”.

Slim DLP technology merges several new advancements in both the design of the overall DLP TV cabinet as well as the underlying electrical and optical components. Combining these new approaches with Texas Instruments latest generation of DLP chipsets allows for much sleeker DLP TV designs to be realized for designs that are compelling to both men and women. These advancements are described in more detail below.

Figure 1. Minimized depth using offset optics

A new optics approach
In order to address depth of the TV cabinet, slim DLP TV changes the way in which the projected image is generated from the light engine. By adapting a projection technique often used in data-projectors (using offset to the projection lens), the depth of a slim DLP TV is decreased by up to 30%. This enables a TV depth of 10″ at 44″ screen size and 11.25″ at 50″ screen size compared to >15″ for conventional DLP TV's. At <11.25" deep,="" both="" 44"="" and="" 50"="" slim="" dlp="" tv's="" use="" less="" shelf="" space="" than="" popular="" 42"="" plasma="" and="" 40"="" lcd="" models.="" flat="" panel="" tv's="" typically="" require="" a="" minimum="" 14"="" deep="" stand="" to="" match="" the="" tip-over="" stability="" of="" a="" slim="" dlp="" tv.="" add="" to="" that="" the="" fact="" that="" 44"="" slim="" sized="" dlp="" can="" weigh="" only="" 50="" lbs,="" much="" less="" than="" equivalent="" sized="" flat="" panel="" tv's,="" and="" you="" have="" a="" very="" compelling="" form="" factor="" for="" the="" consumer.="">

Previous attempts at reducing DLP TV depth required a long “chin” ” the distance from the bottom of the screen to the base of the TV. Previous DLP chipsets were illuminated from the side of the device, whereas newer 0.65″ 1080p and 0.45″ 720p DLP devices are illuminated from the bottom side of the device. This change allows for more compact, lower cost optical components to be used than was previously possible. Bottom illumination also enables a more efficient optical design by simplifying the light path for offset projection. With these smaller optics slim DLP is able reduce the overall weight of the TV set while also minimizing the size of the TV “chin”. A more compact engine and reduced chin height makes it possible to reduce the overall cabinet size and enables sleeker styling options for the industrial design of the TV.

Figure 2. DLP Side versus Bottom Illumination

Figure 3. Slim DLP ” CRT – Plasma comparison

Bezel-less advantage
One inherent advantage that slim DLP technology enjoys is derived from how the image is actually generated on the screen of the HDTV set. Competing flat panel technologies require some amount of screen bezel to mechanically seal and protect the edge of the display panel as well as to house the driver circuitry for the panel itself. With DLP micro-display the image is projected onto a screen and thus it is possible to have a nearly zero-width bezel, extending the image to the edge of the actual TV cabinet. Minimizing the bezel width creates a larger screen size in a smaller TV cabinet, an important criteria for many consumers who are seeking to buy the largest size screen that will fit within the constraints of their existing furniture. As part of the slim DLP TV technology development, Texas Instruments has worked with leading TV brands and screen manufacturers to reduce the bezel width to approximately 0.5″ on new and upcoming slim DLP TV designs from greater than 2″ on previous DLP sets. With this reduction in bezel width a 44″ DLP TV can fit in the same cabinet space as a 40″ LCD TV or popular 36″ direct view CRT's.

Figure 4. Slim DLP Bezel-less screen attachment

Increased modularity
A challenge with more compact designs is the tighter integration required between the DLP and OEM electronics. This was solved by creating a more compact and modular DLP light engine reference design that supported a tightly integrated system design.

At the heart of every DLP HDTV is a group of electrical and mechanical components referred to as a “light engine”. The light engine typically consists of a light source, illumination and projection optics, and the Texas Instruments DLP chipset. Slim DLP light engines offer a more modular approach than previous products, enabling a single slim DLP light engine to support multiple screen sizes and cabinet styles. This in turn allows for more shared tooling and components across screen sizes and TV designs, more flexible styling and easier service access. Slim DLP technology uses TI's newest 720p and 1080p DLP chipsets. The DLP imaging devices are electronically interchangeable thus also making it simple for OEM's to upgrade slim 720p TV models to Full HD – 1080p resolution with minimal changes to the light engines.

Figure 5. Slim DLP light engine modularity

In addition to all the advances mentioned above, slim DLP technology also incorporates other new capabilities that Texas Instruments DLP has recently developed. BrilliantColorTM technology will be incorporated into all new slim DLP TV's, increasing the overall light efficiency of the system and dramatically expanding the realizable color gamut. Texas Instruments has also worked closely with several lamp manufacturers to develop advanced methods of light source control. These new methods make more efficient use of the available lamp spectrum and also increase bit depth in the display without the use of dark segments in the color wheel. With BrilliantColor technology coupled with advances in the lamp pulsing capabilities, slim DLP is able to simultaneously reduce the DLP imager size, while increasing brightness by nearly 50%.

Figure 6. Reduced width using bezel-less screen with slim DLP

See related article Wider color gamuts on DLP display systems through BrilliantColor technology in Digital TV DesignLine.

About the authors
Randy Lawson is a Systems Engineer in the DLP TV Business group where he has been working on developing smaller, low-cost TV systems since re-joining DLP in 2004. Randy joined Texas Instruments in June 1992 after graduating from the University of Tennessee, Knoxville. In the past 14 years with TI Randy has filled various roles from Applications and Systems Engineering for Connectivity Products (1394 CE and storage products), Electrical Design for Professional Display products in DLP and OMAP Hardware Applications in TI's Wireless Group. Randy has authored several technical papers on 1394 for trade magazines Electronic Design and EDN.

Matthew Hine is a Mechanical Systems Engineer for DLP TV and joined Texas Instruments' DLP business in July 2004. At TI, he has designed opto-mechanical systems and TV cabinets, an unusual opportunity to apply both engineering discipline and a passion for industrial design to new DLP TV reference designs. Prior to this, he held various engineering and consumer electronics retail jobs around Texas, following completion of his Mechanical Engineering degree at Rice University. Both authors can be reached at nmendoza@rogersandcowan.com.

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