Use of a lenslet array with a vertically stacked pixel array

• US 6,958,862 B1
• Filed: 04/21/2003
• Issued: 10/25/2005
• Est. Priority Date: 04/21/2003
• Status: Active Grant

• Current Assignee: Foveon, Inc. (Avis Budget Group Incorporated)
• Original Assignee: Foveon, Inc. (Avis Budget Group Incorporated)
• Inventors: Joseph, Domenick Montalbo
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): CHOI, WILLIAM C
• Application Number:
  US10/421,382
• Time in Patent Office: 918 Days
• Field of Search: 257/232, 257/233, 257/291, 257/292, 257/294, 257/432, 359619-622, 349/95, 349/106, 438/70
• US Class Current: 359/621
• CPC Class Codes: G02B 27/1013 for colour or multispectral image sensors, e.g. splitting an image into monochromatic image components on respective sensors spectral imaging systems G01J
• CPC Class Codes: G02B 27/123 The splitting element being a lens or a system of lenses, including arrays and surfaces with refractive power
• CPC Class Codes: G02B 3/0056 arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085
• CPC Class Codes: H01L 27/14621 Colour filter arrangements
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device
• CPC Class Codes: H01L 27/14647 Multicolour imagers having a stacked pixel-element structure, e.g. npn, npnpn or MQW elements
• CPC Class Codes: H04N 2209/042 having a single pick-up sensor
• CPC Class Codes: H04N 2209/047 using multispectral pick-up elements
• CPC Class Codes: H04N 23/84 for processing colour signals
• CPC Class Codes: H04N 25/134 based on three different wavelength filter elements

Abstract

An improved optical imaging system includes a vertically stacked pixel array and a lenslet array for capturing images while minimizing the focal length. The vertically stacked pixel array is configured to operate as an image sensor. The lenslet array is configure to focus the image on the image sensor. Each lens of the lenslet array focuses an image on a sub-array of the image sensor. Each sub-array is shifted from one another so that additional data obtained for each equivalent pixel in each sub-array. An image is obtained by combining the data of each sub-array.

Claims

1. A method for capturing an image, comprising:

positioning a lenslet array parallel to a vertically stacked pixel array, wherein the lenslet array is spaced from the vertically stacked pixel array according to an associated focal length;

focusing light reflected from an image source onto the vertically stacked pixel array, wherein each pixel of the vertically stacked pixel array senses multiple colors of light;

reading data that is associated with each pixel such that an image is obtained, whereby the focal length and color distortion are minimized; and

each pixel of a vertically stacked pixel array corresponds to a vertically stacked photodiode cell, wherein each vertically stacked photodiode cell includes photodiodes formed at different depths in silicon, such that each photodiode is sensitive to a different color of light; and

wherein the vertically stacked pixel array is separated into sub-arrays, wherein each sub-array corresponds to a lens of the lenslet array.

2. The method as in claim 1, wherein focusing light reflected from the image source onto the vertically stacked pixel array further comprises focusing a separate image onto a portion of the vertically stacked pixel array corrsponding to each lens within the lenslet array.

3. The method as in claim 1, wherein each sub-array is shifted away from the other sub-arrays such that data associated with each sub-array is different than data associated with the other sub-arrays.

4. The method as in claim 1, wherein data associated with each sub-array is combined to produce an image that is larger than each individual sub-array.

5. The method as in claim 1, further comprising separating the vertically stacked pixel array into sub-arrays that are each shifted away from each other sub-array, such that an image read by each sub-array includes a center that is different than a center of each other sub-array.

6. The method as in claim 5, further comprising interpreting a pixel associated with a first sub-array as a logically adjacent pixel to an equivalent pixel in second sub-array.

7. The method as in claim 5, further comprising reading an image by a first sub-array that is the same image read by a second sub-array with the center difference, such that data corresponding to the first sub-array and data corresponding to the second sub-array are combined to produce an image that corresponds to the number of pixels in the vertically stacked pixel array.

8. The method as in claim 1, wherein the colors of light sensed by each pixel of the vertically stacked pixel array are blue, green, and red.

9. An optical imaging system, comprising:

a vertically stacked pixel array that is arranged as an image sensor, wherein each pixel of the vertically stacked pixel array senses multiple colors of light;

a lenslet array that is positioned parallel to the vertically stacked pixel array between the vertically stacked pixel array and an image source according to a focal length associated with the lenslet array, such that lenses of the lenslet array focus an image onto the vertically stacked pixel array, whereby an image is read by the vertically stacked pixel array; and

each pixel of a vertically stacked pixel array corresponds to a vertically stacked photodiode cell, wherein each vertically stacked photodiode cell includes photodiodes formed at different depths in silicon that are each sensitive to different colors of light; and

wherein the vertically stacked pixel array is separated into sub-arrays that each correspond to an associated lens within the lenslet array.

10. The optical imaging system as in claim 9, wherein the vertically stacked pixel array includes sub-arrays that are each shifted away from each other sub-array, such that an image read by each sub-array includes a center that is different than a center of each other sub-array.

11. The optical imaging system as in claim 10, wherein a first sub-array includes a pixel that is interpreted as a logically adjacent pixel to an equivalent pixel included in second sub-array.

12. The optical imaging system an in claim 10, wherein an image read by a first sub-array is the same image read by a second sub-array with the center difference, such that data corresponding to the first sub-array and data corresponding to the second sub-array are combined to produce an image that corresponds to the number of pixels in the vertically stacked pixel array.

13. An optical imaging system for capturing an image, comprising:

multiple means for sensing light that are arranged in an array, wherein each means for sensing light is arranged to sense multiple colors of light;

multiple means for focusing light that are arranged in an array, wherein the means for focusing light are spaced from the means for sensing light according to an associated focal length;

means for interpreting data associated with each means for sensing light such that an image is obtained, whereby the focal length and color distortion are minimized;

a means for associating each pixel of a vertically stacked pixel array to a corresponding vertically stacked photodiode cell, wherein each vertically stacked photodiode cell includes photodiodes formed at different depths in silicon that are each sensitive to different colors of light; and

wherein the array means for sensing light is separated into sub-arrays, wherein each sub-array corresponds to a selected means for focusing light.

14. The optical imaging system as in claim 13, wherein each sub-array is shifted away from the other sub-arrays such that data associated with each sub-array is different than data associated with the other sub-arrays.

15. The optical imaging system as in claim 13, wherein data associated with each sub-array is combined to produce an image that is larger than each individual sub-array.