Color uniformity in compact LED illumination for DMD projectors

We present compact illumination engines for DMD projection systems making use of light emitting diodes (LEDs) as light sources. The impact of uniformization optics and color-combining dichroic filters is investigated with respect to the color uniformity on the screen. PhlatLight LEDs are considered as light sources because of their superior luminance levels. Also PhotonVacuum optics are used to collimate and transform the emitted LED light distribution. The optical engines are simulated with advanced non-sequential ray tracing software. They are evaluated on the basis of étendue efficiency, compactness and color uniformity of the projected images. Color plots are used as tools to investigate the simulated color gradients in the image. To validate our simulation models, we have built a compact prototype LED projector. Its color-related specifications are compared with the simulated values.

[1]  Larry J. Hornbeck,et al.  Digital Light Processing for high-brightness high-resolution applications , 1997, Electronic Imaging.

[2]  Ho-chi Huang,et al.  14.1: Power Considerations of Color‐Filter LCOS, Embedded Pico‐Projector, Electronic Architectures for Mobile Phones , 2009 .

[3]  Alfred Poor.  Display Week 2009 Review: Projection , 2009 .

[4]  Chih-Ming Wang,et al.  High efficiency pocket-size projector with a compact projection lens and a light emitting diode-based light source system. , 2008, Applied optics.

[5]  Peter Dannberg,et al.  Homogeneous LED-illumination using microlens arrays , 2005, SPIE Optics + Photonics.

[6]  Hugo Thienpont,et al.  Projection display for the generation of two orthogonal polarized images using liquid crystal on silicon panels and light emitting diodes. , 2008, Applied optics.

[7]  Hugo Thienpont,et al.  Using a fly’s eye integrator in efficient illumination engines with multiple light-emitting diode light sources , 2007 .

[8]  Jannick Rolland,et al.  Optimization of freeform lightpipes for light-emitting-diode projectors. , 2008, Applied optics.

[9]  Youri Meuret,et al.  Design of a compact projection display for the visualization of 3‐D images using polarization sensitive eyeglasses , 2009 .

[10]  Gunther Wyszecki,et al.  Color Science: Concepts and Methods, Quantitative Data and Formulae, 2nd Edition , 2000 .

[11]  Hugo Thienpont,et al.  Two LCOS full color projector with efficient LED illumination engine , 2009, Displays.

[12]  F. L. Pedrotti,et al.  Introduction to Optics 2nd Edition , 1993 .

[13]  Youri Meuret,et al.  Optical design of a compact illumination system for LED projection displays , 2008, SPIE Photonics Europe.

[14]  Lingjing Wang,et al.  P-177: LED Projectors Based on Angular Color Method , 2009 .

[15]  Hugo Thienpont,et al.  Stereoscopic projector for polarized viewing with extended color gamut , 2010, Displays.

[16]  Matthew S. Brennesholtz,et al.  Projection Displays , 1999 .

[17]  Hugo Thienpont,et al.  Efficient illumination in LED-based projection systems using lenslet integrators , 2006, SPIE Photonics Europe.

[18]  Gaurav Sharma.  Digital Color Imaging Handbook , 2002 .

[19]  Christian Hoepfner.  61.1: Invited Paper: PhlatLight™ Photonic Lattice LEDs for RPTV Light Engines , 2006 .

[20]  Marcel P. C. M. Krijn,et al.  LED-based mini-projectors , 2006, SPIE Photonics Europe.

[21]  Hugo Thienpont,et al.  Comparison of the light output of LCOS projection architectures using LEDs , 2008, Displays.

[22]  Hugo Thienpont,et al.  14.1: Efficient and Compact Illumination in LED Projection Displays , 2007 .