Image sensors with diffractive lenses for stray light control
AssigneeSemiconductor Components Industries, LLC
InventorByounghee Lee
Life of this patent
Estimating the term…
Abstract
An image sensor may include an array of imaging pixels. Each imaging pixel may have a photosensitive area that is covered by a microlens and a diffractive lens that focuses light onto the photosensitive area. The diffractive lens may be interposed between the microlens and the photosensitive area. The diffractive lens may have a higher index of refraction than the surrounding materials. The diffractive lens may be formed as a portion of an anti-reflection coating. In some cases, multiple diffractive lenses may be formed over the imaging pixels. Focusing and defocusing diffractive lenses may be used to tune the response of the imaging pixels to incident light.
Claims15
An image sensor comprising a plurality of imaging pixels, wherein each imaging pixel of the plurality of imaging pixels comprises:
- a photodiode;
- a microlens formed over the photodiode;
- and
- a diffractive lens interposed between the photodiode and the microlens, wherein the diffractive lens of each imaging pixel has a first refractive index, wherein the diffractive lens of each imaging pixel is surrounded by a respective layer of material that has a second refractive index that is less than the first refractive index, wherein the respective layer of material for each imaging pixel forms a portion of a respective color filter element for that imaging pixel, wherein the respective color filter element for each imaging pixel has a first portion with a first thickness and a second portion with a second thickness that is greater than the first thickness, wherein the first portion is formed over the diffractive lens of that imaging pixel, and wherein the second portion is formed around the diffractive lens of that imaging pixel.
An image sensor comprising a plurality of imaging pixels, wherein each imaging pixel of the plurality of imaging pixels comprises:
- a photodiode;
- a microlens formed over the photodiode;
- and
- a diffractive lens interposed between the photodiode and the microlens, the image sensor further comprising an anti-reflective coating that is formed over the plurality of imaging pixels between the photodiodes of the imaging pixels and the diffractive lenses of the imaging pixels, wherein the anti-reflective coating has first portions with a first thickness and second portions with a second thickness that is greater than the first thickness and wherein the second portions of the anti-reflective coating form the diffractive lenses of the plurality of imaging pixels.
An imaging pixel comprising:
- a photosensitive area;
- a color filter element formed over the photosensitive area;
- a microlens formed over the color filter element;
- and
- a diffractive lens formed between the color filter element and the photosensitive area, wherein the diffractive lens is transparent, wherein the diffractive lens has first and second opposing surfaces, wherein the first and second surfaces of the diffractive lens are planar, and wherein the color filter element laterally surrounds the diffractive lens.
Dependencies are inferred from the claim text.