Image sensor with stripes of cyan filter material perpendicular to stripes of yellow filter material

• US 6,529,239 B1
• Filed: 06/01/1998
• Issued: 03/04/2003
• Est. Priority Date: 06/01/1998
• Status: Expired due to Term

• Current Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Original Assignee: Fairchild Imaging, Inc. (BAE Systems Plc)
• Inventors: Aulakh, Inderjit K., Dyck, Rudolph H.
• Primary Examiner(s): HO, TUAN V
• Application Number:
  US09/088,137
• Time in Patent Office: 1,737 Days
• Field of Search: H04/N.5225, 348/207, 348/342, 348/335, 348/360, 348/311, 348/272, 348/273, 348/275, 348/276, 348/277, 348/278, 348/281, 437/225, 437/2, 437/3, 437/4
• US Class Current: 348/279
• CPC Class Codes: H01L 31/02162 for filtering or shielding light, e.g. multicolour filters for photodetectors
• CPC Class Codes: H04N 25/133 including elements passing panchromatic light, e.g. filters passing white light
• CPC Class Codes: H04N 25/135 based on four or more different wavelength filter elements

Abstract

A CCD image sensor with a color filter array (CFA) for color imaging involves stripes of Cyan and of Yellow filter material on the imaging surface of a CCD array, preferably a full-frame (FF) CCD imager, with the two sets of color stripes arranged perpendicular to each other and one set parallel to the array axes to form two layers at the areas where they cross. Unit color cells comprise 2-pixel by 2-pixel blocks, each containing a Cyan, a Yellow, a Green (where the stripes overlap), and a White (where there is no stripe) pixel. Also, the longitudinal set can be segmented into two pixels or more in length, and the segments transversely displaced or staggered to form an elongated checkerboard pattern to compensate for devices with single-column blemishes. In fabrication, the filter stripes of one color are deposited crossing over the others to form two layers with different thicknesses so that the later deposited stripe has spectral properties in the cross-over regions distinctly different from non-cross-over regions, permitting the production of a four-color image CCD sensor chip with fewer fabrication steps and improved yield. The resulting chip has the sensed image charge read out after only one exposure to generate the desired color image data file, and a 2×2 pixel block of a unit cell can be virtually shifted by one pixel both longitudinally and transversely so that complementary 2×2 pixel blocks can also be used to generate unique color image data. Another arrangement using Cyan and Yellow filter material in the form of circular discs or octagons is also disclosed.

Claims

1. A CCD color image sensor, comprising:

a CCD array;

a plurality of continuous stripes of Cyan filter material disposed over said CCD array parallel to an axis of said CCD array; and

a plurality of continuous stripes of Yellow filter material disposed over said CCD array and arranged perpendicular to said stripes of Cyan filter material,

wherein said plurality of continuous stripes of Cyan filter material and said plurality of continuous stripes of Yellow filter material are arranged in separate layers with one layer passing over the other layer in crossing regions, and said pluralities of continuous stripes are arranged to form 2-pixel by 2-pixel blocks, with each block containing a Cyan pixel, a Yellow pixel, a Green pixel where the stripes overlap, and a White pixel where there is no stripe, and with the Cyan and Yellow pixels diagonally opposed and the Green and White pixels diagonally opposed.

2. A sensor as in claim 1 further comprising a planarizing layer of polyimide disposed between said separate layers.

3. A sensor as in claim 1 further comprising a thin refractory metal mask on said CCD array under said separate layers.

4. A sensor as in claim 1 wherein said one layer passing over said other layer has a substantially constant thickness and color quality, in said crossing regions and in regions where said layers do not cross.

5. A sensor as in claim 1 wherein said one layer passing over said other layer has a different thickness and different color quality, in said crossing regions and in regions where said layers do not cross.

6. A sensor as in claim 1 wherein said other layer has a different thickness and different color quality, in said crossing regions and in regions where said layers do not cross.

7. A CCD color image sensor, comprising:

a CCD array;

a plurality of stripes of Cyan filter material disposed over said CCD array parallel to an axis of said CCD array; and

a plurality of stripes of Yellow filter material disposed over said CCD array and arranged perpendicular to said stripes of Cyan filter material,

wherein said plurality of stripes of Cyan filter material and said plurality of stripes of Yellow filter material are arranged in separate layers with one layer passing over the other layer in crossing regions, and said pluralities of stripes are arranged to form 2-pixel by 2-pixel blocks, with each block containing a Cyan pixel, a Yellow pixel, a Green pixel where the stripes overlap, and a White pixel where there is no stripe, and with the Cyan and Yellow pixels diagonally opposed and the Green and White pixels diagonally opposed, and

wherein one of said plurality of stripes of Cyan filter material and said plurality of stripes of Yellow filter material is arranged transversely and continuously across said CCD array, and the other one of said plurality of stripes of Cyan filter material and said plurality of stripes of Yellow filter material is arranged longitudinally, and each of said other one of said plurality of stripes of Cyan filter material and said plurality of stripes of Yellow filter material is segmented and alternately displaced transversely to form a checkerboard pattern with said one of said plurality of stripes of Cyan filter material and said plurality of stripes of Yellow filter material.