Image Sensor Pixel Electrode Asymmetry for High Chief Ray Angle Sensitivity

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Solution Overview

Problem

Film-based image sensors face challenges in enhancing performance, particularly in handling high chief ray angles and achieving efficient image capture due to limitations in pixel electrode design and microlens alignment, leading to reduced sensitivity at the edges of the image sensor array.

Innovation Solution

The design involves spatially offsetting pixel electrodes and microlenses relative to the regular grid in the peripheral regions of the image sensor array, with pixel electrodes enlarged in certain directions to improve light collection at high chief ray angles, and using a quantum film as the photosensitive medium to enhance image sensing capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If pixel electrodes are arranged in a regular grid pattern, then manufacturing is simplified, but sensitivity at peripheral regions for high chief ray angles deteriorates

Engineering Contradiction:

Improvepixel electrode arrangementVSAvoidsensitivity at peripheral regions

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies asymmetry by offsetting pixel electrodes in peripheral regions from the regular grid pattern. Specifically, pixels in peripheral regions are shifted in directions away from the center of the array, creating an asymmetric arrangement that compensates for the angled incidence of light at high chief ray angles, thereby improving sensitivity without complicating the overall regular grid manufacturing process

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent implements local quality by applying different electrode arrangements to different regions of the sensor array. Central region pixels maintain regular grid alignment while peripheral region pixels are offset, allowing each region to be optimized for its specific optical conditions - central pixels for near-normal incidence and peripheral pixels for high chief ray angles

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If microlenses are aligned with the regular grid, then alignment manufacturing is easier, but light collection efficiency at high chief ray angles is reduced

Engineering Contradiction:

Improvemicrolens alignmentVSAvoidlight collection efficiency

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies asymmetry by offsetting microlenses in peripheral regions from the regular grid pattern, matching the offset pattern of the pixel electrodes. This asymmetric arrangement allows microlenses to properly focus high chief ray angle light onto the corresponding offset pixel electrodes, improving light collection efficiency while maintaining compatibility with standard manufacturing processes

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent implements local quality by applying different microlens alignment strategies to different regions. Central region microlenses remain aligned with the regular grid while peripheral region microlenses are offset, allowing each region to be optimized for its specific light collection requirements

Inventive Principle:

Principle #3Local quality

3Measurement precision

If pixel electrodes are offset in peripheral regions, then sensitivity at high chief ray angles is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improvesensitivity at high chief ray anglesVSAvoidelectrode positioning accuracy

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent applies segmentation by dividing the sensor array into central and peripheral regions with different electrode arrangements. This segmentation allows the offset pattern to be applied only where needed (peripheral regions) while maintaining the simple regular grid pattern in central regions, thereby reducing the overall manufacturing precision burden compared to a complete offset pattern

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enhances the sensitivity and performance of image sensors by effectively capturing light at high angles, reducing losses in peripheral regions and improving overall image quality, while maintaining a compact camera module design.

Implementation Method 1

a silicon-based switching array is overlaid with a photosensitive film such as a film containing a dispersion of quantum dots... is coupled by suitable electrodes to the film in order to read out the photocharge that accumulates in each pixel of the film due to incident light

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 2

a photosensitive film such as a film containing a dispersion of quantum dots... accumulates in each pixel of the film due to incident light

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS11251218B2Image sensors with enhanced wide-angle performance

Publication Date: 2022.02.15 INVISAGE TECHNOLOGIES INC

AI summary

Imaging apparatus (2000, 2100, 2200) includes a photosensitive medium (2004, 2204) and an array of pixel circuits (302), which are arranged in a regular grid on a semiconductor substrate (2002) and define respective pixels (2006, 2106) of the apparatus. Pixel electrodes (2012, 2112, 2212) are connected respectively to the pixel circuits in the array and coupled to read out photocharge from respective areas of the photosensitive medium to the pixel circuits. The pixel electrodes in a peripheral region of the array are spatially offset, relative to the regular grid, in respective directions away from a center of the array.