Two LCOS full color projector with efficient LED illumination engine

Abstract

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.

Demonstration of a home projector based on RGB semiconductor lasers

“…In Table 2 we summarize the possible losses in three color channels. The efficiencies through the projection system for red, blue, and green are, respectively, 36.9%, 37.2%, and 40.7%, much higher-more than 1.5 times-than the efficiency of the projector reported in [21][22]. And the efficiencies of the illumination system (from light-collecting optics to relay system) for red, blue, and green are 87.3%, 84.7%, and 88%, respectively, which are also much higher than the value (58%) reported in [23].…”

“…And the efficiencies of the illumination system (from light-collecting optics to relay system) for red, blue, and green are 87.3%, 84.7%, and 88%, respectively, which are also much higher than the value (58%) reported in [23]. As stated in [21][22][23], LEDs are used as light sources in the projection systems based on LCOS technology. The light of LEDs is unpolarized and the LED etendue is much higher than LCOS etendue.…”

An electrostatically driven 2D micro-scanning mirror with capacitive sensing for projection display

“…For imaging-type projectors, image pixels are produced by the corresponding pixel arrays in the imaging device. Notable examples include the DLP (digital light processing) [1] and LCoS (liquid crystal on silicon) [2][3][4] technologies. This work belongs to the second type, aiming at demonstrating a laser beam scanning projector using a bi-axial micro-scanning mirror.…”

Compact LED projector design with high uniformity and efficiency

“…The advantages of LEDs include energy saving, environmental protection, small size, and long service life [1]. With the development of LEDs, many projectors have been designed using LEDs as the light source to project images on the screen [2][3][4][5][6][7]. In 1987, digital light processing projection technology was developed by Texas Instruments.…”