Stacked Image Sensor Color Filter Array Light Absorption
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Solution Overview
Problem
There is a need for image sensors with improved light absorption efficiency and sensitivity, particularly in reducing size while maintaining or enhancing performance, as existing technologies face challenges in achieving high sensitivity and luminance characteristics, especially under low light environments.
Innovation Solution
The proposed image sensor features a novel structure with a color filter array comprising a combination of first and second color filters, where the second color filters are equal to or greater in quantity than the first, and are configured to selectively transmit mixed light spectra, including combinations of blue, green, and red light, alongside a photoelectric device with a light absorption layer that selectively absorbs specific visible light wavelengths, enhancing light absorption efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the image sensor uses a conventional non-stacked structure, then the manufacturing process is simpler, but the light absorption efficiency and sensitivity are insufficient
Solution Approach 1:
The patent transitions from a planar non-stacked structure to a three-dimensional stacked structure, where the color filter array and photoelectric device are positioned at different vertical levels. This dimensional change allows light to be absorbed more efficiently as it passes through multiple layers, resolving the contradiction between maintaining simple manufacturing and improving light absorption efficiency.
Solution Approach 2:
The patent implements a nested structure where the color filter array is positioned above the photoelectric device, with light passing through the color filters first and then being absorbed by the photoelectric device below. This nested arrangement maximizes light absorption efficiency while maintaining a compact form factor, addressing the contradiction between structural complexity and performance.
2Volume of moving object
If the image sensor reduces its size using stacking structure, then the device miniaturization is achieved, but the sensitivity and luminance characteristics deteriorate
Solution Approach 1:
By arranging the color filter array and photoelectric device in different vertical layers rather than horizontally adjacent positions, the patent achieves size reduction through the stacking structure while maintaining sensitivity. The vertical arrangement allows light to pass through multiple functional layers without increasing the horizontal footprint, thus miniaturizing the sensor while preserving luminance characteristics.
Solution Approach 2:
The patent divides the image sensor into distinct functional segments - the color filter array layer and the photoelectric device layer - which are stacked vertically. This segmentation allows each layer to be optimized independently for its specific function while working together to maintain overall sensitivity, resolving the contradiction between size reduction and sensitivity preservation.
3Reliability
If the color filter array uses only first color filters for each pixel, then the structure is simpler, but the light absorption efficiency is reduced
Solution Approach 1:
The patent makes the color filter array multi-functional by including both first color filters (aligned with photoelectric devices) and second color filters (filling gaps between pixels). The second color filters absorb light that would otherwise be wasted, directing it to adjacent photoelectric devices. This universal approach increases overall light absorption efficiency while adding manageable complexity to the color filter array structure.
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 results in a highly sensitive image sensor with improved light absorption efficiency, effectively mitigating sensitivity and luminance deterioration under low light conditions, and achieving greater than twice the light absorption efficiency of conventional non-stacked image sensors.
Implementation Method 1
a light absorption layer between the pair of electrodes, the light absorption layer being configured to selectively absorb the first visible light
Implementation Method 2
photoelectric device... light absorption layer being configured to selectively absorb the first visible light
Implementation Method 3
a color filter array, the color filter array including a quantity of first color filters and a quantity of second color filters
Data Source
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AI summary
An electronic device may include at least one image sensor (200) that includes a plurality of photo-sensing devices (50a, 50b), a photoelectric device (30) on one side of the semiconductor substrate (110) and configured to selectively sense first visible light, and a plurality of color filters (70) on corresponding photo-sensing devices, respectively. The plurality of color filters may include a first color filter (70a) configured to selectively transmit a second visible light that is different from the first visible light and a second color filter (70b) transmitting first mixed light including the second visible light. The electronic device may include multiple unit arrays of color filters. The electronic device may include different photoelectric devices on the separate unit arrays of color filters. The different photoelectric devices may be configured to sense different wavelength spectra of light.