Image sensor

Abstract

An image sensor includes a photodiode, a color filter layer disposed on the photodiode, and a metalayer disposed on the color filter layer. The metalayer includes a first pixel unit, which includes blue, first green, second green, and red regions respectively on blue, first green, second green, and red filter layers. The blue region includes a first nanopillar adjacent to the center of the first pixel unit, the first green region includes a second nanopillar adjacent to the center of the first pixel unit, the second green region includes a third nanopillar adjacent to the center of the first pixel unit, and the red region includes a fourth nanopillar adjacent to the center of the first pixel unit. The first to fourth nanopillars are arranged in a kite shape.

Claims

1. An image sensor, comprising: a plurality of photodiodes; a color filter layer disposed on the photodiodes, wherein the color filter layer includes a blue filter, a red filter, a first green filter, and a second green filter arranged in a Bayer configuration; and an overlay layer disposed on the color filter layer and including a first pixel unit, the first pixel unit including a blue region on the blue filter, a red region on the red filter, a first green region on the first green filter, and a second green region on the second green filter, wherein the blue region includes a central nanopillar of the blue region and a plurality of peripheral nanopillars surrounding the central nanopillar of the blue region; wherein the first green region includes a central nanopillar of the first green region and a plurality of peripheral nanopillars surrounding the central nanopillar of the first green region. The second green region includes a central nanopillar and a plurality of peripheral nanopillars surrounding the central nanopillar; the red region includes a central nanopillar and a plurality of peripheral nanopillars surrounding the central nanopillar; the peripheral nanopillars of the blue regions include a first nanopillar adjacent to a center of the first pixel unit, the peripheral nanopillars of the first green regions include a second nanopillar adjacent to the center of the first pixel unit, the peripheral nanopillars of the second green regions include a third nanopillar adjacent to the center of the first pixel unit, and the peripheral nanopillars of the red regions include a fourth nanopillar adjacent to the center of the first pixel unit; and a first distance between the first nanopillar and the second nanopillar is equal to a second distance between the first nanopillar and the third nanopillar, a third distance between the fourth nanopillar and the second nanopillar is equal to a fourth distance between the fourth nanopillar and the third nanopillar, and the first distance is different from the third distance.

2. The image sensor as claimed in claim 1, wherein the angle between the line connecting the second nanopillar to the center of the first pixel unit and the boundary between the first green region and the red region is 45 degrees; the angle between the line connecting the first nanopillar to the center of the first pixel unit and the boundary between the first green region and the red region is 135 degrees; the angle between the line connecting the third nanopillar to the center of the first pixel unit and the boundary between the first green region and the red region is 225 degrees; and the angle between the line connecting the fourth nanopillar to the center of the first pixel unit and the boundary between the first green region and the red region is 315 degrees.

3. The image sensor as claimed in claim 1, wherein a first line connecting the first nanoparticle pillar to the fourth nanoparticle pillar is orthogonal to a second line connecting the second nanoparticle pillar to the third nanoparticle pillar, and a pixel size of each of the photodiodes is between 800 nanometers and 3000 nanometers.

4. The image sensor as claimed in claim 1, wherein the blue region comprises a plurality of inner-circular nanopillars within the blue region, disposed between and surrounding the central nanopillar of the blue region and the peripheral nanopillars of the blue region, wherein the inner-circular nanopillars within the blue region satisfy the following equation: = where is the minimum angle between two adjacent inner-circular nanopillars within the blue region, is the distance from each inner-circular nanopillar within the blue region to a center of the blue region, is the radius of each inner-circular nanopillar within the blue region, and is the minimum spacing between two adjacent inner-circular nanopillars within the blue region.

5. The image sensor as claimed in claim 4, wherein the number of each ring of nanopillars in the blue regions satisfies the following equation: , where is the largest integer not greater than x.

6. The image sensor as claimed in claim 4, wherein the inner ring nanopillars within the blue region satisfy one of the following equations: where i is the azimuth angle from each of the inner ring nanopillars within the blue region to the center of the blue region, i is zero or an integer between 1 and 4A-1, where i is the largest integer not greater than x; or where i is the azimuth angle from each of the inner ring nanopillars within the blue region to the center of the blue region, i is zero or an integer between 1 and 4A-2, where i is the largest integer not greater than x.

7. The image sensor as claimed in claim 6, wherein the nanopillars within the blue regions satisfy the following equation: , where is the pixel size of each of the photodiodes.

8. The image sensor as claimed in claim 1, wherein the blue region includes a plurality of inner ring nanopillars within the blue region, disposed between and surrounding the central nanopillar of the blue region and the peripheral nanopillars of the blue region; the first green region includes a plurality of inner ring nanopillars within the first green region, disposed between and surrounding the central nanopillar of the first green region and the peripheral nanopillars of the first green region; the second green region includes a plurality of inner ring nanopillars within the second green region, disposed between and surrounding the central nanopillar of the second green region and the peripheral nanopillars of the second green region; the red region includes a plurality of inner ring nanopillars within the red region, disposed between and surrounding the central nanopillar of the red region and the peripheral nanopillars of the red region; and the number of inner ring nanopillars within the blue regions is the same as or different from the number of inner ring nanopillars within the first green regions, the number of inner ring nanopillars within the second green regions, or the number of inner ring nanopillars within the red regions.

9. The image sensor as claimed in claim 1, wherein in a top view, the central nanopillar of the first green region is offset relative to a center of the first green region by a first longitudinal offset in the Y-axis direction and a first lateral offset in the X-axis direction; and in the top view, the central nanopillar of the second green region is offset relative to a center of the second green region by a second longitudinal offset in the Y-axis direction and a second lateral offset in the X-axis direction.

10. The image sensor as claimed in claim 9, wherein the first longitudinal offset and the first lateral offset are determined by an incident angle and an azimuth angle of the first green region; wherein the incident angle of the first green region is the angle between a first incident light illuminating an upper surface of the first green region and a normal to the upper surface of the first green region; and wherein the azimuth angle of the first green region is the angle between a transverse axis of the metalayer and a first line connecting the center of the first green region and the center of the metalayer, wherein the transverse axis of the metalayer passes through the center of the metalayer.

11. The image sensor as claimed in claim 10, wherein the metalayer further includes a second pixel unit, the second pixel unit includes a third green region, the third green region includes a central nanopillar of the third green region, and in the top view, the central nanopillar of the third green region is offset relative to a center of the third green region by a third longitudinal offset in the Y-axis direction and a third lateral offset in the X-axis direction, wherein the third longitudinal offset and the third lateral offset are determined by an incident angle and an azimuth angle of the third green region; wherein the incident angle of the third green region is the angle between a second incident light illuminating a surface of the third green region and a normal to the surface of the third green region; wherein the azimuth angle of the third green region is the angle between the transverse axis of the metalayer and a second line connecting the center of the third green region and the center of the metalayer; and wherein the first longitudinal offset of the central nanopillar of the first green region and the third longitudinal offset of the central nanopillar of the third green region satisfy the following equation: Wherein, is the incident angle of the first green area and is not equal to zero degrees, is the azimuth angle of the first green area, is the first longitudinal offset of the first green area, is the incident angle of the third green area and is not equal to zero degrees, is the azimuth angle of the third green area, is the third longitudinal offset of the third green area, is a first difference between the incident angle of the first green area and the incident angle of the third green area, and is a second difference between the azimuth angle of the first green area and the azimuth angle of the third green area.

12. The image sensor as claimed in claim 11, wherein the edge of the first green region is offset relative to the corresponding edge of the first green filter by a first green region offset, the color filter layer includes a third green filter, the third green region is located on the third green filter, and the edge of the third green region is offset relative to the corresponding edge of the third green filter by a third green region offset, wherein the first green region offset and the third green region offset satisfy the following equation: where is the first green region offset, is the third green region offset, wherein the first green region offset is between 0 and 300 nanometers, greater than 0 degrees and less than or equal to 35 degrees, and between 0 degrees and 360 degrees.

13. The image sensor as described in claim 1, wherein: The refractive index of the metalayer is between 1.8 and 3.5; the image sensor further includes a filler layer covering the metalayer, wherein the refractive index of the filler layer is between 1.8 and 3.5; and the image sensor further includes a spacer layer disposed between the metalayer and the color filter layer, wherein the refractive index of the spacer layer is between 1 and 1.6, and the height of the spacer layer is between 100 nanometers and 500 nanometers.

14. The image sensor as claimed in claim 1, wherein the refractive index of each of the blue filter, the red filter, the first green filter and the second green filter is between 1.4 and 2.3, and the color filter layer further includes a grid disposed to separate the blue filter, the red filter, the first green filter and the second green filter, and the refractive index of the grid is between 1 and 1.3.

Images