58.1: Single-Panel LCOS Color Projector with LED Light Sources

Zou, Hans; Schleicher, Adam; Dean, John

doi:10.1889/1.2036343

Cited by 19 publications

(17 citation statements)

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“…Further optimizations in the projection lens and LED optics would certainly improve these two compact projectors for mobile display applications. The spatial-color projector has cost and compactness advantages, while the sequential-color projector has better color and the potential to produce more output through 3 RGB LED arrays and an x-cube [9].…”

Section: Resultsmentioning

confidence: 99%

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P‐188: Single‐Panel Spatial‐Color and Sequential‐Color LCOS Projectors Using LED Lamps

Huang

Leung

Kwok

et al. 2007

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We present and compare two single-panel LCOS projectors using LED lamps. The 0.59" sequential-color LCOS microdisplay with integrated frame buffers can deliver 10.5 lm by a 4W red, green and blue LED. The 0.59" spatial-color LCOS microdisplay with white sub-pixels can deliver 14 lm by a 6W white LED. IntroductionLiquid-crystal-on-silicon (LCOS) microdisplay has been developed for more than 10 years [1,2]. There are three kinds of LCOS microdisplays, arranged in different manners for various applications. The first one was a monochrome and highresolution microdisplay developed in early 1990, and arranged in three-panel architectures for rear projection television (RPTV) applications [3,4]. The second one was a color-sequential microdisplay developed in late 1990, and arranged in single-panel architectures for near-to-eye and RPTV applications [5~7]. The third one was a spatial-color microdisplay developed in early 2000, and arranged in single-panel architectures for near-to-eye and mini-projector applications [8]. These three kinds of LCOS microdisplays and projectors were not designed for use with light emitting diodes (LEDs). But as the fast development of power LEDs, the prospect of using LEDs as light sources for these three LCOS projectors has been greatly increased [9~11].A Corner of 3M applied red, green and blue (RGB) LED lamps to a three-panel LCOS projector, which used three 0.61" SVGA panels, and obtained 267 lm [10]. H Zou of Philips Research replaced the scrolling prism in a single-panel sequential-color projector, which used a 1.3" progressive-scan SXGA panel, by sequential RGB LED lamps and obtained 44 lm [9]. It was expected that the output could be improved to 135 lm if the progressive-scan LCOS panel was replaced by a frame-loading one. H S Lo of ITRI proposed optical designs for very compact mini-projectors using 0.38" color-filter LCOS panels [11]. But the output was low due to the light absorption by RGB color filters.In this paper, we present our works on single-panel spatial-color and sequential-color LCOS projectors using LED lamps. We added white sub-pixels to the color-filter LCOS panel to increase the panel reflectivity from typically 20% to 32%. The output of the spatial-color LCOS projector was correspondingly improved. We integrated frame buffers to the sequential-color LCOS panel to eliminate the frame loading time. As a result, the optical efficiency of the sequential-color LCOS projector was greatly improved. Moreover, the sequential-color LCOS projector had enough time budgets for RGB and white (RGBW) color sequence for more optical output. Spatial-Color LCOS ProjectorThe color-filter LCOS microdisplays were designed to be used with low-cost halogen lamps for low-cost video projectors. Figure 1 shows a palm-size spatial-color LCOS projector using a 50W halogen lamp in a MR11 package. The projector could produce 20 lumen output from a 0.47" VGA panel with a color gamut of 35% NTSC level, which was limited by low color temperature of the halogen lamp. (a) (b) Figure 1 (a) Spatial-co...

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Section: Resultsmentioning

confidence: 99%

“…H Zou of Philips Research replaced the scrolling prism in a single-panel sequential-color projector, which used a 1.3" progressive-scan SXGA panel, by sequential RGB LED lamps and obtained 44 lm [9]. It was expected that the output could be improved to 135 lm if the progressive-scan LCOS panel was replaced by a frame-loading one.…”

Section: Introductionmentioning

confidence: 99%

P‐188: Single‐Panel Spatial‐Color and Sequential‐Color LCOS Projectors Using LED Lamps

Huang

Leung

Kwok

et al. 2007

Symp Digest of Tech Papers

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“…Not only does the étendue increase, but also the light extraction from the LEDs. Theoretically the maximal achievable gain would be 2.35 12 . The actual gain is usually not sufficient to maintain the brightness (lumen/étendue) and is a little bit lower, namely about 2.…”

Section: Led Performances and Color Balancingmentioning

confidence: 98%

Two LCOS full color projector with efficient LED illumination engine

et al. 2009

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LED-based projectors have numerous advantages compared to traditional projectors. They are more compact, exhibit a larger color gamut and a longer lifetime, the supply voltage is lower and they can operate on batteries. However their light output is limited by the low optical power per étendue of the LEDs, although this is also improving constantly. With an efficient illumination engine design we can build an LED projector with a moderate light output and with superior properties. We present a compact LED projector with two 'Liquid Crystal On Silicon' (LCOS) panels. One of these panels is alternately modulating red and blue information while the other permanently modulates the green information to achieve the D65 white point. This architecture is first simulated using ray-tracing software. After testing the several parts of this architecture experimentally, we have built a demonstrator setup. Our demonstrator produces a moderate light output (37.3 lm) on screen with a sufficient contrast ratio and a very good uniformity, within a system étendue lower than 20 mm 2 sr. In spite of semi color sequential working, the color breakup and crosstalk are negligible.

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“…Conventional systems typically combine different colors of light from separate LEDs using tilted dichroic mirrors. [2][3][4][5][6] The most compact arrangement places the mirrors at 45°to the light bundle. This configuration suffers efficiency losses due to polarization-dependent effects and because of the angular spread of the light bundle.…”

Section: Tilted Dichroic Mirrorsmentioning

confidence: 99%

Compact, high‐brightness LED illumination for projection systems

Bruzzone

English²,

Aastuen

2009

J Soc Info Display

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Abstract— An arrangement consisting of a polarizing beam splitter, retarders, and dichroic mirrors provides a compact and efficient combiner for red, green, and blue light from separate LED packages. The resulting illuminating beam is unpolarized. In initial tests, a 0.55‐in. DMD engine based on this illuminator produced an on‐screen flux of 188 lm from 58 W of LED input power, using an f/2.4 pupil. Subsequent work with the same imager and LED set has resulted in a compact and efficient 300‐lm projector.

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58.1: Single-Panel LCOS Color Projector with LED Light Sources

Cited by 19 publications

References 1 publication

P‐188: Single‐Panel Spatial‐Color and Sequential‐Color LCOS Projectors Using LED Lamps

P‐188: Single‐Panel Spatial‐Color and Sequential‐Color LCOS Projectors Using LED Lamps

Two LCOS full color projector with efficient LED illumination engine

Compact, high‐brightness LED illumination for projection systems

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