Stacked Photoelectric Sensor Layout for Stable Optical Black Signals
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Solution Overview
Problem
In laminated photoelectric conversion apparatuses, excess charges can mix with the optical black (OB) region, leading to inaccurate detection of black level reference signals and improper correction of pixel values.
Innovation Solution
The apparatus includes a first substrate with a semiconductor device layer containing effective pixel and optical black pixel regions, and a second substrate with a circuit for processing signals. An outer periphery region with a charge draining region is introduced, where a semiconductor region of the same conductivity type as the signal charge is used, and a fixed potential is supplied to drain excess charges, preventing them from mixing with the OB region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If charge draining pixels are disposed between the effective pixel region and the OB region to drain signal charges leaking from the effective pixel region, then signal charges leaking from the effective pixel region are drained, but excess charges from the periphery of the OB region cannot be prevented from mixing in the OB region
Solution Approach 1:
The patent divides the peripheral region into two distinct segments: an optical black pixel region for receiving leaked signal charges and an outer periphery region for generating excess charges. This segmentation prevents excess charges from the outer periphery from contaminating the optical black pixel region, thereby maintaining black level reference signal detection accuracy while still draining signal charges from the effective pixel region.
Solution Approach 2:
The patent introduces an intermediary region (outer periphery region with charge draining function) between the effective pixel region and the optical black pixel region. This intermediary structure, equipped with charge draining pixels and light-blocking regions, acts as a mediator to prevent excess charges from reaching the optical black pixel region while allowing signal charges to be properly drained.
2Ease of operation
If OB pixels are placed in the end portion of the substrate, then the OB region is positioned for signal processing, but excess charges from the periphery of the OB region mix in the OB region causing black level reference signals to fluctuate
Solution Approach 1:
The patent applies preliminary anti-action by placing light-blocking regions and charge draining pixels in the outer periphery region before excess charges can contaminate the optical black pixel region. This preventive measure blocks light from reaching the outer periphery region and actively drains any excess charges that may form, thereby preventing black level reference signal fluctuations before they occur.
3Reliability
If a light-blocking region overlaps the optical black pixel region, then signal charges leaking from the effective pixel region are drained, but excess charges from the outer periphery region can still mix in the OB region
Solution Approach 1:
The patent applies local quality by creating different functional zones with distinct properties: the optical black pixel region has light-blocking characteristics for receiving signal charges, while the outer periphery region has charge-draining characteristics with light-blocking regions. This localized differentiation ensures that each region performs its specific function optimally without interfering with the other, preventing excess charge contamination while maintaining signal charge draining capability.
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 solution effectively prevents excess charges from contaminating the OB region, thereby enhancing the accuracy of black level reference signal detection and ensuring proper pixel value correction in laminated photoelectric conversion apparatuses.
Implementation Method 1
a light-blocking region formed by a light-blocking layer overlaps the optical black pixel region, and the light-blocking region does not overlap the outer periphery region
Implementation Method 2
the outer periphery region has a charge draining region including a semiconductor region of the same conductivity type as a signal charge, and wherein a fixed potential is supplied to the charge draining region
Data Source
AI summary
A photoelectric conversion apparatus includes a first substrate having a first semiconductor device layer including a plurality of photoelectric conversion units and a well, and a second substrate having a second semiconductor device layer including a circuit configured to process signals obtained by the plurality of photoelectric conversion units, wherein the first and second substrates are laminated together, wherein the first semiconductor device layer includes an effective pixel region, an optical black pixel region, and an outer periphery region, wherein, in a planar view, a light-blocking region formed by a light-blocking layer overlaps the optical black pixel region, and the light-blocking region does not overlap the outer periphery region, wherein the outer periphery region has a charge draining region including a semiconductor region of the same conductivity type as a signal charge, and wherein a fixed potential is supplied to the charge draining region.