Pixel Light Shielding for Sensitivity Uniformity in Solid-State Imaging
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Solution Overview
Problem
Solid-state imaging apparatuses with tiled imaging blocks face issues of line defects and image distortion due to varying pixel sensitivity caused by different photoelectric conversion element areas, leading to inconsistent performance across the sensor panel.
Innovation Solution
A solid-state imaging apparatus with a light shielding layer that includes a light shielding portion and an aperture for each pixel, where the area of the light shielding portion is proportionally larger for pixels with larger photoelectric conversion element areas to equalize sensitivity, and the apertures are designed to maintain uniform light exposure across pixels with different areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pixels with different photoelectric conversion element areas are used in tiled imaging blocks, then the sensor panel can be constructed with modular units, but sensitivity varies between pixels
Solution Approach 1:
The patent applies local quality by introducing a light shielding layer with spatially varying aperture areas. Each pixel receives a customized amount of light based on its position and photoelectric conversion element area. Pixels with larger areas receive proportionally less light through smaller apertures, while pixels with smaller areas receive more light through larger apertures, thereby equalizing sensitivity across the tiled sensor panel.
Solution Approach 2:
The patent changes the parameter of light aperture area in the light shielding layer to compensate for variations in photoelectric conversion element areas. By adjusting the aperture size parameter inversely to the photoelectric conversion element area, the system maintains uniform sensitivity across pixels with different areas, resolving the contradiction between modular construction and sensitivity uniformity.
2Device complexity
If scanning circuits are arranged at the periphery of pixel arrays in unit cells, then integration is simplified, but line defects occur at tile boundaries
Solution Approach 1:
The patent applies local quality by providing different aperture sizes in the light shielding layer for pixels at different positions within unit cells. Pixels adjacent to tile boundaries receive customized light shielding to compensate for the line defects caused by peripheral scanning circuit arrangements, while interior pixels receive standard shielding. This localized adjustment maintains image quality at tile boundaries without increasing overall device complexity.
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
The solution effectively reduces sensitivity variation between pixels, enhancing the uniformity and accuracy of image capture across the sensor panel by adjusting the light shielding and aperture areas to match the size of the photoelectric conversion elements, thereby improving image quality and reducing distortion.
Implementation Method 1
a light shielding layer covering the photoelectric conversion element, wherein for each of the photoelectric conversion elements of the plurality of pixels, the light shielding layer includes a light shielding portion which shields a portion of incident light to the photoelectric conversion element
Data Source
AI summary
A solid-state imaging apparatus including pixels each including a photoelectric conversion element, and a light shielding layer covering the photoelectric conversion element is provided. For each of the photoelectric conversion elements, the light shielding layer includes a light shielding portion which shields a portion of incident light to the photoelectric conversion element, and an aperture which passes another portion of the incident light. The pixels include first and second pixels which have different areas on a planar view of the photoelectric conversion element. The area of the photoelectric conversion element in the first pixel is larger than the area of the photoelectric conversion element in the second pixel on the planar view. An area of the light shielding portion included in the first pixel is larger than an area of the light shielding portion included in the second pixel.