# US 10,310,285 B2 · Wafer-level liquid-crystal-on-silicon projection assembly, systems and methods

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- Number: US 10,310,285 B2
- Document ID: US10310285B2
- Status: Granted
- Kind: B2
- Application number: 15/817,064
- Filed: 2017-11-17
- Published: 2018-04-05
- Granted: 2019-06-04
- Earliest claimed: 2014-05-15
- Assignees: OmniVision Technologies, Inc.
- Applicants: OmniVision Technologies, Inc.
- Inventors: Chun-Sheng Fan
- Web page: https://patentgrep.com/patent/US10310285B2

## CPC

- G02B 30/25: using polarisation techniques
- G02B 13/0085: {employing wafer level optics}
- G02B 13/16: for use in conjunction with image converters or intensifiers {, or for use with projectors, e.g. objectives for projection TV}
- G02B 27/0172: {characterised by optical features}
- G03B 21/006: {using LCD's}
- G03B 21/2066: {Reflectors in illumination beam (in projection beam G03B21/28)}
- G03B 21/2073: {Polarisers in the lamp house (peculiar to electronic spatial light modulators H04N9/3197)}
- H10W 90/00: Package configurations
- G02B 2027/0178: {Eyeglass type (eyeglass details G02C)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## 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

### Claim 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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 2)

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.

### Claim 4 (depends on 3)

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.

### Claim 5 (depends on 2)

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.

### Claim 6 (depends on 1)

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.

### Claim 7 (depends on 1)

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.

### Claim 8 (depends on 1)

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.