US6049094A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low stress package assembly for silicon-backed light valves
Assignee: National Semiconductor Corp
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Filing: 1998-05-21
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Granted: 2000-04-11
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Expires: 2018-05-21
Abstract
Abstract A low-stress silicon-backed light valve package assembly that includes a matched coefficient of thermal expansion (CTE) substrate with a CTE no greater than 300% of the CTE of silicon, a silicon-backed light valve adhered to the matched CTE substrate by a soft adhesive layer, a flexible circuit adhered to the matched CTE substrate and electrically connected to the silicon-backed light valve, an encapsulant dam surrounding the silicon-backed light valve and a soft encapsulant layer filling the cavity defined by the encapsulant dam. Both the soft encapsulant layer and the soft adhesive layer have a Shore A hardness of less than 5. The combination of a soft encapsulant layer, soft adhesive layer and matched CTE substrate insure sufficiently low mechanical stress levels to avoid the presence of optical interference patterns in the light valve display.
Inventors
- 👤 Matthew D. Penry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 20:23
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/133308; G02F1/03; G02F1/0305; G02F2202/00; G02F2202/28; H; H10; H10W; H10W72/00; H10W72/851; H10W72/874; H10W72/884
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
137 words
A silicon-backed light valve package assembly comprising: a matched coefficient of thermal expansion (CTE) substrate; a soft adhesive layer on an upper surface of the matched CTE substrate; a silicon-backed light valve attached to the matched CTE substrate by the soft adhesive layer; a flexible circuit with an opening, the flexible circuit overlaid on the matched CTE substrate so as to expose the silicon-backed light valve through the opening; bonding wires electrically connecting the flexible circuit to the silicon-backed light valve; an encapsulant dam attached to the flexible circuit, the encapsulant dam surrounding the silicon-backed light valve and thereby defining a cavity; and a soft encapsulant layer disposed in the cavity, the soft encapsulant layer at least partially covering the matched CTE substrate, the flexible circuit and the silicon-backed light valve, and completely covering the bonding wires.
Claim 2
Dependent Claim
137 words
A silicon-backed light valve package assembly comprising: a matched coefficient of thermal expansion (CTE) substrate; a soft adhesive layer on an upper surface of the matched CTE substrate; a silicon-backed light valve attached to the matched CTE substrate by the soft adhesive layer; a flexible circuit with an opening, the flexible circuit overlaid on the matched CTE substrate so as to expose the silicon-backed light valve through the opening; bonding wires electrically connecting the flexible circuit to the silicon-backed light valve; an encapsulant dam attached to the flexible circuit, the encapsulant dam surrounding the silicon-backed light valve and thereby defining a cavity; and a soft encapsulant layer disposed in the cavity, the soft encapsulant layer at least partially covering the matched CTE substrate, the flexible circuit and the silicon-backed light valve, and completely covering the bonding wires.
Claim 3
Dependent Claim
21 words
The silicon-backed light valve package assembly of claim 1 wherein the opening is located at one end of the flexible circuit.
Claim 4
Dependent Claim
19 words
The silicon-backed light valve package assembly of claim 1 wherein the matched CTE substrate is fabricated of alumina ceramic.
Claim 5
Dependent Claim
19 words
The silicon-backed light valve package assembly of claim 1 wherein the matched CTE substrate is fabricated of alumina nitride.
Claim 6
Dependent Claim
18 words
The silicon-backed light valve package assembly of claim 1 wherein the matched CTE substrate is fabricated of mullite.
Claim 7
Dependent Claim
17 words
The silicon-backed light valve package assembly of claim 5 wherein the soft adhesive material is an epoxy.
Claim 8
Dependent Claim
18 words
The silicon-backed light valve package assembly of claim 5 wherein the soft adhesive material is a silicone adhesive.
Claim 9
Dependent Claim
19 words
The silicon-backed light valve package assembly of claim 1 wherein the soft adhesive layer comprises a soft adhesive material.
Claim 10
Dependent Claim
19 words
The silicon-backed light valve package assembly of claim 1 wherein the soft encapsulant layer comprises a soft encapsulant material.
Claim 11
Dependent Claim
17 words
The silicon-backed light valve package assembly of claim 8 wherein the soft encapsulant material is an epoxy.
Claim 12
Dependent Claim
18 words
The silicon-backed light valve package assembly of claim 8 wherein the soft encapsulant material is a silicone adhesive.
Claim 13
Dependent Claim
142 words
A silicon-backed light valve package assembly comprising: a matched coefficient of thermal expansion (CTE) substrate; a soft adhesive layer on an upper surface of the matched CTE substrate; a silicon-backed light valve attached to the matched CTE substrate by the soft adhesive layer; a printed circuit board with an opening, the printed circuit board overlaid on the matched CTE substrate so as to expose the silicon-backed light valve through the opening; bonding wires electrically connecting the printed circuit board to the silicon-backed light valve; an encapsulant dam attached to the printed circuit board, the encapsulant dam surrounding the silicon-backed light valve and thereby defining a cavity; and a soft encapsulant layer disposed in the cavity, the soft encapsulant layer at least partially covering the matched CTE substrate, the printed circuit board and the silicon-backed light valve, and completely covering the bonding wires.
Claim 14
Dependent Claim
142 words
A silicon-backed light valve package assembly comprising: a matched coefficient of thermal expansion (CTE) substrate; a soft adhesive layer on an upper surface of the matched CTE substrate; a silicon-backed light valve attached to the matched CTE substrate by the soft adhesive layer; a printed circuit board with an opening, the printed circuit board overlaid on the matched CTE substrate so as to expose the silicon-backed light valve through the opening; bonding wires electrically connecting the printed circuit board to the silicon-backed light valve; an encapsulant dam attached to the printed circuit board, the encapsulant dam surrounding the silicon-backed light valve and thereby defining a cavity; and a soft encapsulant layer disposed in the cavity, the soft encapsulant layer at least partially covering the matched CTE substrate, the printed circuit board and the silicon-backed light valve, and completely covering the bonding wires.
Claim 15
Dependent Claim
161 words
The silicon-backed light valve package assembly comprising: a matched coefficient of thermal expansion (CTE) substrate; a soft adhesive layer on an upper surface of the matched CTE substrate; a silicon-backed light valve attached to the matched CTE substrate by the soft adhesive layer; a flexible circuit with an opening, the flexible circuit overlaid on the matched CTE substrate so as to expose the silicon-backed light valve through the opening; bonding wires electrically connecting the flexible circuit to the silicon-backed light valve; a combined mounting frame and encapsulant dam for providing a means for mounting the silicon-backed light valve package assembly on a next-level assembly, the combined mounting frame and encapsulant dam attached to the flexible circuit, surrounding the silicon-backed light valve and thereby defining a cavity; and a soft encapsulant layer disposed in the cavity, the soft encapsulant layer at least partially covering the matched CTE substrate, the flexible circuit and the silicon-backed light valve, and completely covering the bonding wires.
Claim 16
Dependent Claim
161 words
The silicon-backed light valve package assembly comprising: a matched coefficient of thermal expansion (CTE) substrate; a soft adhesive layer on an upper surface of the matched CTE substrate; a silicon-backed light valve attached to the matched CTE substrate by the soft adhesive layer; a flexible circuit with an opening, the flexible circuit overlaid on the matched CTE substrate so as to expose the silicon-backed light valve through the opening; bonding wires electrically connecting the flexible circuit to the silicon-backed light valve; a combined mounting frame and encapsulant dam for providing a means for mounting the silicon-backed light valve package assembly on a next-level assembly, the combined mounting frame and encapsulant dam attached to the flexible circuit, surrounding the silicon-backed light valve and thereby defining a cavity; and a soft encapsulant layer disposed in the cavity, the soft encapsulant layer at least partially covering the matched CTE substrate, the flexible circuit and the silicon-backed light valve, and completely covering the bonding wires.
Claim 17
Dependent Claim
21 words
The silicon-backed light valve package assembly of claim 13 wherein the opening is located at one end of the flexible circuit.
Claim 18
Dependent Claim
29 words
The silicon-backed light valve package assembly of claim 13 wherein the combined mounting frame and encapsulant dam has a height greater than a height of the silicon-backed light valve.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-04-11 | 2003-10-11 | 2004-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-04-11 | 2007-10-11 | 2008-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-04-11 | 2011-10-11 | 2012-04-11 | $7700.00 | Window Closed / Lapsed |