Wafer-level liquid-crystal-on-silicon projection assembly, systems and methods

• US 10,310,285 B2
• Filed: 11/17/2017
• Issued: 06/04/2019
• 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
• Primary Examiner(s): Gordon, Steven Whitesell
• Assistant Examiner(s): Brooks, Jerry L
• Application Number:
  US15/817,064
• Publication Number:
  US 20180095290A1
• Time in Patent Office: 564 Days
• Field of Search: 353 20
• 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. 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 that includes an arrayed plurality of active matrices for addressing liquid crystal display pixels, the PBS wafer including a plurality of PBS film bands each (i) oriented at 45 degrees to a plane of the active-matrix wafer and (ii) configured to reflect an input illumination toward the active-matrix wafer, a distance between adjacent PBS film bands, of the plurality of PBS film bands, equaling a spacing between rows of the arrayed plurality of active matrices; and

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

2. The method of claim 1, 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.

3. The method of claim 2, the step of aligning comprising aligning the plurality of lenses with a respective one of the plurality of PBS film bands.

4. The method of claim 3, 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.

5. The method of claim 2, 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.

6. The method of claim 1, 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.

7. The method of claim 1, 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.

8. The method of claim 1, 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.