Solid-state image sensors and display devices having anti-reflection film
Solid-state image sensors are disclosed that include an optical unit which separates incident light into a plurality of color elements, an optical receiving unit which converts each of the color elements separated by the optical unit to an electrical signal and an anti-reflection film having a high-refractive-index layer with a refractive index of 1.7 or higher and a low-refractive-index layer with a refractive index of less than 1.7. The anti-reflection film is between the optical unit for each of color elements and the optical receiving unit, on a semiconductor substrate. Each of the high-refractive-index layer and the low-refractive-index layer corresponds to at least one color element of the plurality of color elements and includes two or more layers. With such sensors it is possible to suppress the variation in sensitivity for each color.
1. A solid-state image sensor, comprising:
an optical unit separating incident light into a plurality of color elements;
an optical receiving unit comprising multiple pixels which convert respective color elements separated by said optical unit to corresponding electrical signals; and
an anti-reflection film including a high-refractive-index layer having a refractive index of 1.7 or higher and a low-refractive-index layer having a refractive index of less than 1.7, the anti-reflection film being provided between the optical unit and said optical receiving unit for each of the pixels, wherein
with respect to at least a first color element of the plurality of color elements, the anti-reflection film of the respective pixel comprises a quantity of at least two separate high-refractive-index layers and a quantity of at least two separate low-refractive-index layers; and
with respect to a second color element of the plurality of color elements, the anti-reflection film of the respective pixel comprises a quantity of separate high-refractive-index layers and a quantity of separate low-refractive-index layers that are different from the respective quantities of high-refractive-index layers and low-refractive-index layers of the anti-reflection film of the pixel for the first color element.
2. The solid-state image sensor according to claim 1 , wherein, with respect to at least one pixel for at least one color element, one of film thickness and film material in each high-refractive-index layer and each low-refractive-index layer differs corresponding to the particular corresponding color element.
3. The solid-state image sensor according to claim 2 , wherein, among pixels having two or more separate high-refractive-index layers, film material and film thickness of the layer nearest to said optical receiving unit are the same.
4. The solid-state image sensor according to claim 2 , wherein, among the pixels for each of the color elements, the film material and film thickness of the low-refractive-index layer arranged nearest to the optical receiving unit are the same.
5. The solid-state image sensor according to claim 2 , wherein:
the color elements include a first color element, a second color element, and a third color element; and
the third color element differs from the first and second color elements, and the anti-reflection film of pixels of the third color element includes a single high-refractive-index layer and one or more low-refractive-index layers.
6. The solid-state image sensor according to claim 1 , wherein among pixels having two or more separate high-refractive-index layers, film material and film thickness of the high-refractive-index layer nearest to the optical receiving unit are the same.
7. The solid-state image sensor according to claim 6 , wherein, among the pixels for each of the color elements, the film material and film thickness of the low-refractive-index layer arranged nearest to the optical receiving unit are the same.
8. The solid-state image sensor according to claim 6 , wherein:
the color elements include a first color element, a second color element, and a third color element; and
the third color element differs from the first and second color elements, and the anti-reflection film of pixels of the third color element includes a single high-refractive-index layer and one or more low-refractive-index layers.
9. The solid-state image sensor according to claim 1 , wherein, among the pixels for each of the color elements, the film material and film thickness of the low-refractive-index layer arranged nearest to the optical receiving unit are the same.
10. The solid-state image sensor according to claim 9 , wherein:
the color elements include a first color element, a second color element, and a third color element; and
the third color element differs from the first and second color elements, and the anti-reflection film of pixels of the third color element includes a single high-refractive-index layer and one or more low-refractive-index layers.
11. The solid-state image sensor according to claim 1 , wherein:
the color elements include a first color element, a second color element, and a third color element; and
the third color element differs from the first and second color elements, and the anti-reflection film of pixels of the third color element includes a single high-refractive-index layer and one or more low-refractive-index layers.
12. The solid-state image sensor according to claim 11 , wherein said first color element is green light, said second color element is blue light, and said third color element is red light.
13. The solid-state image sensor according to claim 1 , wherein, among pixels having two ore more separate high-refractive-index layers, film material and film thickness of the layer nearest to said optical receiving unit are the same.
14. The solid-state image sensor according to claim 1 , wherein, among the pixels for the first color element and the pixels for the second color element, film thicknesses of the respective low-refractive-index layers closest to the optical receiving unit are the same.
15. The solid-state image sensor according to claim 1 , wherein, among the pixels for the first color element and the pixels for the second color element, film thicknesses of the respective high-refractive-index layers closest to the optical receiving unit are the same.