Lens array and manufacturing method therefor, solid-state imaging apparatus, and electronic apparatus

Patent metadata

Field	Value
Publication number	US-10088608-B2
Application number	US-201415021764-A
Country	US
Kind code	B2
Filing date	Sep 12, 2014
Priority date	Sep 25, 2013
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

The present technology relates to a lens array and a manufacturing method therefor, a solid-state imaging apparatus, and an electronic apparatus that can improve the AF performance while suppressing the deterioration of image quality. A lens array includes microlenses that are formed corresponding to phase difference detection pixels that are provided to be mixed in imaging pixels. Each of the microlenses is formed such that a lens surface thereof is a substantially spherical surface, the microlens has a rectangular shape in a planar view and four corners are not substantially rounded, and a bottom surface in vicinity of an opposite-side boundary portion that includes an opposite-side center portion of a pixel boundary portion in a cross-sectional view is higher than a bottom surface in vicinity of a diagonal boundary portion that includes a diagonal boundary portion. The present technology is applicable to a lens array of a CMOS image sensor, for example.

First claim

The invention claimed is:

1. A lens array, comprising:
a microlens that corresponds to a phase difference detection pixel, wherein the phase difference detection pixel is mixed with an imaging pixel,
wherein the microlens comprises:
a lens surface that is a substantially spherical surface, the microlens has a square shape in a planar view and four corners of the microlens are not substantially rounded,
a first bottom surface in vicinity of an opposite-side boundary portion that includes an opposite-side center portion of a pixel boundary portion, and a second bottom surface in vicinity of a diagonal boundary portion that includes a diagonal boundary portion,
wherein the first bottom surface in a cross-sectional view is higher than the second bottom surface,
the lens surface has a first curvature radius r 1 and a second curvature radius r 2 , the first curvature radius r 1 is a curvature radius in a cross-section of the opposite-side center portion and the second curvature radius r 2 is a curvature radius of the lens surface in a cross-section of the diagonal boundary portion,
the curvature radius of the lens surface is r=(d 2 +4t 2 )/8t, where d denotes a width of a third bottom surface of the microlens in a cross-section that extends through a top of the lens surface and t denotes a height of the top of the lens surface with the third bottom surface as a reference, and
wherein a curvature radius ratio r 1 /r 2 between the first curvature radius r 1 and the second curvature radius r 2 is a value in a range of 0.98 to 1.20.

2. The lens array according to claim 1 , further comprising at least one inorganic film is on a top surface of the lens surface, and wherein the at least one inorganic film is an antireflection film.

3. The lens array according to claim 2 , wherein a difference between the first curvature radius r 1 and the second curvature radius r 2 is based on the at least one inorganic film.

4. A manufacturing method for a lens array, the method comprising:
forming a microlens that corresponds to a phase difference detection pixel, wherein the phase difference detection pixel is mixed with an imaging pixel,
wherein the microlens is formed such that:
a lens surface of the microlens is a substantially spherical surface, the microlens has a square shape in a planar view and four corners of the microlens are not substantially rounded,
a first bottom surface of the microlens is in vicinity of an opposite-side boundary portion that includes an opposite-side center portion of a pixel boundary portion,
a second bottom surface of the microlens is in vicinity of a diagonal boundary portion that includes a diagonal boundary portion,
the first bottom surface in a cross-sectional view is higher than the second bottom surface,
the lens surface has a first curvature radius r 1 and a second curvature radius r 2 , the first curvature radius r 1 is a curvature radius in a cross-section of the opposite-side center portion and the second curvature radius r 2 is a curvature radius of the lens surface in a cross-section of the diagonal boundary portion,
the curvature radius of the lens surface is r=(d 2 +4t 2 )/8t, where d denotes a width of a third bottom surface of the microlens in a cross-section extending through a top of the lens surface and t denotes a height of the top of the lens surface with the third bottom surface as a reference, and
a curvature radius ratio r 1 /r 2 between the first curvature radius r 1 and the second curvature radius r 2 is a value in a range of 0.98 to 1.20.

5. A solid-state imaging apparatus, comprising:
a lens array that includes a plurality of microlenses, each microlens of the plurality of microlenses corresponds to a phase difference detection pixel, wherein the phase difference detection pixel is mixed with an imaging pixel,
wherein a microlens of the plurality of microlenses comprises:
a lens surface that is a substantially spherical surface, the microlens has a square shape in a planar view and four corners of the microlens are not substantially rounded,
a first bottom surface in vicinity of an opposite-side boundary portion that includes an opposite-side center portion of a pixel boundary portion, and
a second bottom surface in vicinity of a diagonal boundary portion that includes a diagonal boundary portion,
wherein the first bottom surface in a cross-sectional view is higher than the second bottom surface,
the lens surface has a first curvature radius r 1 and a second curvature radius r 2 , the first curvature radius r 1 is a curvature radius in a cross-section of the opposite-side center portion and the second curvature radius r 2 is a curvature radius of the lens surface in a cross-section of the diagonal boundary portion,
the curvature radius of the lens surface is r=(d 2 +4t 2 )/8t, where d denotes a width of a third bottom surface of the microlens in a cross-section that extends through a top of the lens surface and t denotes a height of the top of the lens surface with the third bottom surface as a reference, and
wherein a curvature radius ratio r 1 /r 2 between the first curvature radius r 1 and the second curvature radius r 2 is a value in a range of 0.98 to 1.20.

6. An electronic apparatus, comprising:
a solid-state imaging apparatus that includes:
a lens array, wherein the lens array includes a plurality of microlenses, and each microlens of the plurality of microlenses corresponds to a phase difference detection pixel, and wherein the phase difference detection pixel is mixed with an imaging pixel,
wherein a microlens of the plurality of microlenses comprises:
a lens surface that is a substantially spherical surface, the microlens has a square shape in a planar view and four corners of the microlens are not substantially rounded,
a first bottom surface in vicinity of an opposite-side boundary portion that includes an opposite-side center portion of a pixel boundary portion, and
a second bottom surface in vicinity of a diagonal boundary portion that includes a diagonal boundary portion,
wherein the first bottom surface in a cross-sectional view is higher than the second bottom surface,
the lens surface has a first curvature radius r 1 and a second curvature radius r 2 , the first curvature radius r 1 is a curvature radius in a cross-section of the opposite-side center portion and the second curvature radius r 2 is a curvature radius of the lens surface in a cross-section of the diagonal boundary portion,
the curvature radius of the lens surface is r=(d 2 +4t 2 )/8t, where d denotes a width of a third bottom surface of the microlens in a cross-section that extends through a top of the lens surface and t denotes a height of the top of the lens surface with the third bottom surface as a reference, and
wherein a curvature radius ratio r 1 /r 2 between the first curvature radius r 1 and the second curvature radius r 2 is in a range of 0.98 to 1.20.

Assignees

• Sony Corp

Inventors

• Ootsuka Yoichi
• Nishikido Kenju
• YOSHIBA Ippei

Classifications

• G03B13/36

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• G02B3/0025

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• G02B1/113

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• G02B7/34

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• G02B3/0056 Primary

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