Wafer-Level Liquid-Crystal-On-Silicon Projection Assembly, Systems and Methods

• US 20150331305A1
• Filed: 05/15/2014
• Published: 11/19/2015
• Est. Priority Date: 05/15/2014
• Status: Active Grant

• Current Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Original Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Inventors: Fan, Chun-Sheng
• Granted Patent: US 9,851,575 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02B 13/0085 employing wafer level optics
• CPC Class Codes: G02B 13/16 for use in conjunction with image converters or intensifiers , or for use with projectors, e.g. objectives for projection TV
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 30/25 using polarisation techniques
• CPC Class Codes: G03B 21/006 using LCD's
• CPC Class Codes: G03B 21/2066 Reflectors in illumination beam in projection beam G03B21/28
• CPC Class Codes: G03B 21/2073 Polarisers in the lamp house peculiar to electronic spatial light modulators H04N9/3197
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• CPC Class Codes: H01L 25/50 Multistep manufacturing processes of assemblies consisting of devices, each device being of a type provided for in group H01L27/00 or H01L29/00 H01L21/50 takes precedence
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A wafer-level liquid-crystal-on-silicon (LCOS) projection assembly includes a LCOS display for spatially modulating light incident on the LCOS display and a polarizing beam-separating (PBS) layer for directing light to and from the LCOS display. A method for fabricating a LCOS projection system includes disposing a PBS wafer above an active-matrix wafer. The active-matrix wafer includes a plurality of active matrices for addressing liquid crystal display pixels. The method, further includes disposing a lens wafer above the PBS wafer. The lens wafer includes a plurality of lenses. Additionally, a method for fabricating a wafer-level polarizing beam includes bonding a PBS wafer and at least one other wafer to form a stacked wafer. The PBS wafer includes a PBS layer that contains a plurality of PBS film bands.

Claims

1. Wafer-level liquid-crystal-on-silicon (LCOS) projection assembly, comprising:

a LCOS display for spatially modulating light incident on the LCOS display; and

a polarizing beam-separating (PBS) layer for directing light to and from the LCOS display.

2. The LCOS projection assembly of claim 1, the PBS layer configured to reflect light towards the LCOS display and transmit at least a portion of light received from the LCOS display.

3. The LCOS projection assembly of claim 1, further comprising a lens layer for imaging the display.

4. The LCOS projection assembly of claim 3, the PBS layer being disposed between the LCOS display and the lens layer, such that the PBS layers transmits at least a portion of light from the display to the lens layer.

5. The LCOS projection assembly of claim 4, wherein the lens layer includes a wafer-level compound lens.

6. The LCOS projection assembly of claim 1, further comprising a transparent conducting layer in contact with a plurality of PBS elements within the PBS layer for functioning as an electrode of the LCOS display.

7. The LCOS projection assembly of claim 1, implemented in a near-eye projection display.

8. A method for fabricating a wafer-level liquid crystal on silicon (LCOS) projection systems, comprising:

disposing a polarizing beam-separating (PBS) wafer above an active-matrix wafer, including a plurality of active matrices, for addressing liquid crystal display pixels; and

disposing a lens wafer, including a plurality of lenses, above the PBS wafer.

9. The method of claim 8, further comprising:

aligning the lens wafer, the PBS wafer, and the active-matrix wafer; and

bonding the lens wafer, PBS wafer, and active-matrix wafer to form a stacked wafer.

10. The method of claim 8, further comprising:

singulating a stacked wafer, including the PBS wafer, the active matrix substrate, and the lens wafer, to form a plurality of LCOS projection systems.

11. The method of claim 8, further comprising:

injecting liquid crystal between at least a portion of the PBS wafer and at least a portion of the active-matrix wafer to form a LCOS display.

12. The method of claim 9, the step of aligning comprising aligning the plurality of lenses with a respective plurality of PBS film bands of the PBS wafer.

13. The method of claim 12, the step of aligning further comprising aligning the plurality of PBS film bands with a respective plurality of active matrices of the active-matrix wafer.

14. The method of claim 8, further comprising, preceding the step of disposing the PBS wafer:

disposing a plurality of liquid crystal portions on the active-matrix wafer at locations corresponding to each of the plurality of active matrices.

15. The method of claim 9, further comprising:

singulating the stacked wafer to form a plurality of optical modules; and

injecting a portion of liquid crystal between the active-matrix wafer and the PBS wafer for at least a portion of the plurality of optical modules.

16. A method for fabricating a wafer-level polarizing beam separator comprising bonding a polarizing beam-separating (PBS) wafer, including a PBS layer that contains a plurality of PBS film bands, to at least one other wafer, to form a stacked wafer.

17. The method of claim 16, further comprising:

singulating the stacked wafer to form a plurality of PBS modules, each PBS module including at least one of the plurality of PBS film bands.

18. The method of claim 16, the step of bonding comprising bonding the PBS wafer to an active-matrix wafer.

19. The method of claim 18, further comprising placing liquid crystal on the active-matrix wafer to form a display wafer including a plurality of displays.

20. The method of claim 19, further comprising, before the step of placing liquid crystal, forming dams for at least partially containing a plurality of portions of the liquid crystal in the plurality of displays, respectively.

21. The method of claim 16, further comprising forming the PBS layer, the step of forming the PBS layer comprising:

stacking alternating substrates and PBS dielectric films to form a stack; and

dicing the stack at an oblique angle to the planes of the PBS dielectric films to form the PBS layer.

22. The method of claim 21, the step of dicing comprising dicing the stack at an angle of substantially 45 degrees to the planes of the PBS dielectric films.