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

• US 9,851,575 B2
• Filed: 05/15/2014
• Issued: 12/26/2017
• 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): Whitesell Gordon, Steven H
• Assistant Examiner(s): BROOKS, JERRY L.
• Application Number:
  US14/278,452
• Publication Number:
  US 20150331305A1
• Time in Patent Office: 1,321 Days
• Field of Search: 353 20, 353121, 359583, 35948503, 35948911, 35948917, 356326, 369 4414, 36911216
• 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 polarizing beam separator comprising:

bonding a polarizing beam-separating (PBS) wafer to an active matrix wafer to form a stacked wafer, the PBS wafer including a PBS layer having a plurality of PBS film bands, a pair of adjacent PBS film bands thereof being separated by a substrate portion, the active matrix wafer spanning the pair of adjacent PBS film bands, the active matrix wafer including a plurality of active matrices for addressing liquid crystal display pixels; and

singulating the stacked wafer along a plurality of parallel planes that are perpendicular to a top surface of the active matrix wafer such that at most one PBS film band of the plurality of PBS film bands is between two adjacent parallel planes of the plurality of parallel planes.

2. The method of claim 1, further comprising placing liquid crystal on the active-matrix wafer to form a display wafer including a plurality of displays.

3. The method of claim 2, 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.

4. The method of claim 1, 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.

5. The method of claim 4, the step of dicing comprising dicing the stack at an angle of substantially 45 degrees to the planes of the PBS dielectric films.