Laminated Detection Element for Aperture Rate and Accuracy
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Solution Overview
Problem
Existing solid-state imaging devices face limitations in performance due to increased circuit complexity per pixel, leading to a drop in aperture rate and detection accuracy, especially when dealing with background light components.
Innovation Solution
The proposed detection device incorporates a direct current removing section formed by laminating multiple substrates, utilizing a high pass filter composed of a resistor and capacitor to attenuate background light, while maintaining a high light amount for accurate distance information calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If circuit added for each pixel is increased or enlarged to improve detection accuracy, then detection accuracy is improved, but aperture rate drops
Solution Approach 1:
The patent moves circuit elements from the same plane as photodiodes to a stacked three-dimensional architecture. Support substrates carry circuit elements above the photodiode array plane, enabling vertical separation that increases aperture rate while preserving detection accuracy through maintained electrical connections via conductive structures.
Solution Approach 2:
The patent divides the imaging device into functionally separate stacked layers: photodiode arrays on one substrate, support substrates carrying circuit elements above, and distinct functional regions for light reception, signal processing, and control. This segmentation allows each layer to be optimized independently.
2Productivity
If pixel density is increased to improve imaging performance, then imaging performance is improved, but background light interference increases
Solution Approach 1:
The patent extracts and removes DC components representing background light interference through dedicated DC removing circuits. Capacitive coupling structures and high-pass filter circuits separate AC signal components (containing distance information) from DC background components, eliminating harmful background light effects while preserving useful imaging signals.
Solution Approach 2:
The patent introduces capacitive coupling structures as intermediary elements between photodiodes and readout circuits. These capacitors block DC background light components while transmitting AC modulated light signals, acting as frequency-selective mediators that separate useful signals from harmful interference.
3Measurement precision
If multiple substrates are laminated to remove DC components, then background light removal is improved, but device complexity increases
Solution Approach 1:
The patent designs support substrates that simultaneously serve multiple functions: mechanical support for circuit elements, electrical connection pathways via conductive structures, DC component blocking through capacitive coupling, and structural framework for the stacked architecture. This multi-functionality reduces overall device complexity despite multiple substrates.
Solution Approach 2:
The patent merges support substrate functions with circuit board functions, combining mechanical support, electrical interconnection, and signal processing capabilities into integrated stacked layers. Conductive structures serve both as mechanical support pillars and as electrical connection pathways, reducing the need for separate components.
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 approach enhances the detection accuracy by effectively removing background light components, improving the aperture rate, and allowing for high-density light-receiving sections, thus maintaining effective performance even with increased pixel density.
Implementation Method 1
utilizing a high pass filter composed of a resistor and capacitor to attenuate background light
Implementation Method 2
a light-receiving element which is a photodiode
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A detector comprises a plurality of photoelectric converters to output an electrical signal corresponding to an incident light, and a plurality of filter circuits provided corresponding to each of the plurality of photoelectric converters or to each of a plurality of element groups respectively including a predetermined number of the photoelectric converters of the plurality of photoelectric converters, the plurality of filter circuits attenuating a signal having a predetermined frequency from the electrical signal output from the plurality of photoelectric converters. In the above-described detector, the plurality of photoelectric converters may be provided in a first substrate, and the plurality of filter circuits may be provided in a second substrate laminated on the first substrate.