Flexible segmented image sensor

• US 20080151089A1
• Filed: 12/22/2006
• Published: 06/26/2008
• Est. Priority Date: 12/22/2006
• Status: Active Grant

• Current Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Original Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Inventors: Sambandan, Sanjiv, Street, Robert A., Lu, Jeng Ping
• Granted Patent: US 7,742,090 B2
• Time in Patent Office: Days
• US Class Current: 348/308
• CPC Class Codes: H01L 27/14601 Structural or functional details thereof
• CPC Class Codes: H01L 27/14692 Thin film technologies, e.g. amorphous, poly, micro- or nanocrystalline silicon
• CPC Class Codes: H01L 31/03921 including only elements of Group IV of the Periodic Table
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof
• CPC Class Codes: H04N 25/702 SSIS architectures characterised by non-identical, non-equidistant or non-planar pixel layout
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

A method of making a curved sensor is described. The method involves projecting portions of a curved three dimensional structure such as a hemisphere onto a two dimensional substrate in an outline pattern. The outline pattern typically serves as a perimeter of a sensor. After forming a sensor in the shape of the outline pattern, the two dimensional substrate is flexed to form a three dimensional sensor structure.

Claims

1. A method of forming a segmented curved sensor comprising:

forming an array of pixels, each pixel including both detectors and interconnect lines, over a planar surface of a flexible substrate in a pattern, a perimeter of the pattern shaped to form in a two-dimensional plane at least a portion of a three dimensional curved sensor;

using a first force to flex the flexible substrate out of the two dimensional plane such that the sensor curves to form at least a portion of the three-dimensional curved sensor.

2. The method of claim 1 wherein the sensor is an amorphous silicon sensor monolithically formed on the flexible substrate.

3. The method of claim 1 wherein the operation of forming a sensor over a planar substrate of a flexible substrate in a pattern further comprising the operations of:

forming the addressable pixel sensor over the flexible substrate in a pattern; and

,

cutting the flexible substrate such that perimeter of the pattern approximately forms at least a portion of a segmented hemisphere pattern in a two-dimensional display.

4. The method of claim 1 further comprising:

forming address lines on the sensor such that after the force flexes the flexible substrate into at least a portion of an approximate hemisphere, a first set of address lines runs in an approximately axial direction and a second set of address lines run in an approximately azimuthal direction.

5. The method of claim 1 wherein the pattern includes joints between adjacent segments of the pattern such that a second force applied to the pattern causes bending at joints such that the first derivative of the substrate surface at each joint is discontinuous.

6. The method of claim 5 wherein the first force causes flexing in a first direction and the second force causes bending in a second direction, the first direction approximately perpendicular to the second direction.

7. The method of claim 1 wherein the first force that curves each hemispherical segment is caused by an internal stress gradient.

8. The method of claim 7 wherein the stress gradient is caused by a thin film deposited adjacent the substrate.

9. The method of claim 1 wherein the perimeter of the pattern outlines a plurality of hemisphere segments, the hemisphere segments bent at joints between the hemisphere segments to form a three dimensional hemispherical sensor, the cross section of the hemispherical sensor being approximately circular.

10. The method of claim 9 wherein the hemisphere segments are approximately polygonal in shape.

11. The method of claim 10 wherein the at least one of the polygonal shapes is hexagonal.

12. The method of claim 9 wherein at least one of the hemispherical segments is approximately triangular in shape.

13. The method of claim 1 wherein the perimeter of the pattern outlines a plurality of hemispherical segments, the perimeter pattern further including thin strips that include address lines interconnecting the hemispherical segments such that when the segments are flexed out of the two dimensional plane to form at least a portion of the three dimensional curved sensor, the address lines interconnecting segments curl out of an arc that includes the hemispherical formed by the hemisphere segments.

14. A segmented hemispherical sensor comprising:

a first pixelated curved sensor segment;

a second pixelated curved sensor segment, the first curved sensor segment and the second curved sensor segment joined together at a joint to form at least a portion of a hemisphere.

15. The segmented hemispherical sensor of claim 14 further comprising:

a third pixelated curved sensor segment, the third curved sensor segment joined to the second curved sensor segment to form at least a portion of a hemisphere.

16. The segmented hemispherical sensor of claim 15 wherein the joint between the first curved sensor segment and the second curved sensor segment is formed by bending the sensor in a region between the first curved sensor segment and the second curved sensor segment.

17. The segmented hemispherical sensor of claim 14 wherein the first curved sensor segment includes a plurality of pixels, each pixel addressed by a gate line and a data line.

18. The segmented hemispherical sensor of claim 17 wherein each pixel includes a thin film transistor.

19. The segmented hemispherical sensor of claim 14 wherein the first pixelated curved sensor segment and the second pixelated curved sensor segment are joined by address lines that curve out of the arc of the hemisphere formed by the first pixelated curved sensor segment and the second pixelated curved sensor segment.

20. The segmented hemispherical sensor of claim 14 wherein at least one of the pixelated curved sensor segments is a polygon.

21. An imaging system including a segmented hemispherical sensor comprising.

a segmented hemispherical sensor made up of curved hemispherical sensor segments;

a lens system that focuses light in a curved focal plane onto the segmented hemispherical sensor; and

,

an image processor that receives electrical signals from the segmented hemispherical sensor and generate an image.

22. The imaging system of claim 21 wherein the image processor couples to gate lines and data lines in the segmented hemispherical sensor.