Low stress package assembly for silicon-backed light valves
First Claim
1. 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.
1 Assignment
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Accused Products
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.
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Citations
15 Claims
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1. A silicon-backed light valve package assembly comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A silicon-backed light valve package assembly comprising:
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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.
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13. The silicon-backed light valve package assembly comprising:
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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. - View Dependent Claims (14, 15)
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Specification