Illuminating spatial light modulator with led array

Patent metadata

Field	Value
Publication number	US-2023236417-A1
Application number	US-202217648787-A
Country	US
Kind code	A1
Filing date	Jan 24, 2022
Priority date	Jan 24, 2022
Publication date	Jul 27, 2023
Grant date	—

Abstract

Examples are disclosed that relate to a compact optical systems comprising SLMs. One example provides a projection system comprising an illumination stage including a light emitting diode (LED) array. The LED array comprises a plurality of red LEDs, a plurality of green LEDs, and a plurality of blue LEDs. The illumination stage further comprises an illumination stage optical system configured to control an angular extent of light emitted by the LED array and homogenize the light emitted by the LED array. The projection system further comprises an image forming stage configured to form an image from light output by the illumination stage, the image forming stage comprising a spatial light modulator (SLM) configured to spatially modulate the light output by the illumination stage to form an image, and one or more projection optics configured to project the image formed by the spatial light modulator.

First claim

1 . A projection system, comprising
an illumination stage comprising
a light emitting diode (LED) array comprising a plurality of red LEDs, a plurality of green LEDs, and a plurality of blue LEDs, and
an illumination stage optical system configured to control an angular extent of light emitted by the LED array and homogenize the light emitted by the LED array;
an image forming stage configured to form an image from light output by the illumination stage, the image forming stage comprising a spatial light modulator (SLM) configured to spatially modulate the light output by the illumination stage to form an image; and one or more projection optics configured to project the image formed by the spatial light modulator.

2 . The projection system of claim 1 , wherein the illumination stage optical system comprises one or more of a compound parabolic concentrator, a lens array, a microlens array, or a lens.

3 . The projection system of claim 1 , wherein the illumination stage optical system comprises a planar non-imaging optic.

4 . The projection system of claim 3 , wherein the planar non-imaging optic comprises a diffuser.

5 . The projection system of claim 3 , wherein the planar non-imaging optic comprises a brightness enhancing film.

6 . The projection system of claim 3 , wherein the planar non-imaging optic comprises a dual brightness enhancing film.

7 . The projection system of claim 3 , wherein the planar non-imaging optic is configured to output light to a polarizing beam splitter.

8 . The projection system of claim 1 , wherein the SLM comprises a liquid crystal on silicon (LCOS) display.

9 . The projection system of claim 1 , wherein the illumination stage optical system comprises a light guide, the light guide comprising an input coupler configured to receive light from the LED array, and an output coupler configured to output light to the image forming stage.

10 . The projection system of claim 9 , wherein the input coupler comprises a polarizing grating.

11 . The projection system of claim 1 , wherein the projection system is incorporated into an augmented reality head-mounted display device.

12 . A projection system, comprising
an illumination stage comprising
a light emitting diode (LED) array comprising a plurality of red LEDs, a plurality of green LEDs, and a plurality of blue LEDs, and
an illumination stage optical system configured to control an angular extent of the light emitted by the LED array and homogenize the light emitted by the LED array;
a polarizing spatial light modulator configured to receive light from the illumination stage optical system, polarize the light and form an image; and one or more projection optics configured to project the image formed by the spatial light modulator.

13 . The projection system of claim 12 , wherein the illumination stage optical system comprises one or more of a compound parabolic concentrator, a lens array, a microlens array, or a lens.

14 . The projection system of claim 12 , wherein the illumination stage optical system comprises a planar non-imaging optic.

15 . The projection system of claim 14 , wherein the planar non-imaging optic comprises a diffuser.

16 . The projection system of claim 14 , wherein the planar non-imaging optic comprises a brightness enhancing film.

17 . The projection system of claim 14 , wherein the planar non-imaging optic comprises a dual brightness enhancing film.

18 . The projection system of claim 14 , wherein the planar non-imaging optic is coupled to a beam splitter of the image forming stage.

19 . The projection system of claim 12 , wherein the polarizing spatial light modulator comprises a liquid crystal on silicon (LCOS) panel.

20 . Enacted on a projection system comprising a light emitting diode (LED) array comprising a plurality of red LEDs, a plurality of green LEDs, and a plurality of blue LEDs, an illumination stage optical system, an image forming stage comprising a spatial light modulator (SLM), and one or more projection optics, a method, comprising:
outputting light from the LED array toward the illumination stage optical system; controlling an angular extent of and homogenize the light emitted by the LED array via the illumination stage optical system; outputting the light from the illumination stage optical system to the image forming stage; controlling the SLM to form an image; and projecting the image via one or more projection optics.

Assignees

• Microsoft Technology Licensing Llc

Inventors

• Chatterjee Ishan
• Chen Fei
• Kress Bernard Charles
• Pace Maria Esther
• Kollin Joel Steven
• Woltman Scott Jeffrey

Classifications

• G02B27/0101 Primary

  characterised by optical features (G02B27/0172 takes precedence) · CPC title

• G02B27/283

  used for beam splitting or combining · CPC title

• G02B27/4222

  in projection exposure systems, e.g. photolithographic systems · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02B2027/015

  involving arrangement aiming to get less bulky devices · CPC title