Image Sensor Broadband Color Filter and Light Separation
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Solution Overview
Problem
Conventional color filters in image sensors have low light use efficiency due to absorption of unwanted colors, leading to significant light loss and reduced image quality.
Innovation Solution
An image sensor design incorporating a color separation optical structure with a broadband green color filter and a color separation element, which separates incident light by wavelength, and an optimized additional color filter with a fine pattern structure and inorganic material, enhancing light efficiency and maintaining color purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional color filter is used to detect colors, then color detection function is achieved, but light use efficiency deteriorates due to absorption of non-corresponding wavelengths
Solution Approach 1:
The patent divides the pixel array into different types (first pixels with red color filter, second pixels with green color filter, third pixels with blue color filter) and introduces color separation elements that direct different wavelength bands to different pixel types. This segmentation allows each pixel type to receive primarily its corresponding wavelength band, reducing absorption losses while maintaining color detection accuracy.
Solution Approach 2:
The color separation element acts as an intermediary between the incident light and the pixels. It separates the incident light into different wavelength bands and directs each band to the appropriate pixel type, thereby preventing the absorption of non-corresponding wavelengths by incorrect pixel types and improving overall light use efficiency.
2Loss of energy
If a color separation element is introduced to improve light efficiency, then light use efficiency improves, but device complexity increases
Solution Approach 1:
The patent combines the color separation element with the existing color filter array and pixel structure into an integrated optical system. The color separation element is positioned above the pixel array and works in conjunction with the color filters and microlenses, merging multiple optical functions into a unified structure that achieves improved light efficiency without requiring separate complex subsystems.
3Loss of energy
If the green color filter bandwidth is increased to capture more light, then light use efficiency improves, but color purity deteriorates
Solution Approach 1:
The patent applies different bandwidth characteristics to different color filters based on their specific needs. The green color filter is designed with a broader bandwidth to capture more light in the green region, while the red and blue color filters maintain narrower bandwidths. This local differentiation optimizes light capture for each color channel without compromising overall color purity, as each filter's bandwidth is tailored to its specific wavelength region.
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 design improves light utilization efficiency while minimizing light loss and maintaining high color purity, achieving a balance between light efficiency and image quality.
Implementation Method 1
A color separation element may separate incident light into different colors using the diffraction or refraction characteristics of light that vary according to wavelength.
Implementation Method 2
A color separation element may separate incident light into different colors using the diffraction or refraction characteristics of light that vary according to wavelength.
Implementation Method 3
a broad green color filter having a spectrum which meets predetermined conditions is located at the bottom
Data Source
Figure 1~2A
Figure 2B~3
Figure 4~5
AI summary
Provided is an image sensor comprising a color separation element (131). The image sensor includes a pixel array including a plurality of a first pixels (110a), a plurality of second pixels (110b), and a plurality of third pixels (110c); color separation elements configured to direct light in a second wavelength band travel toward the second pixels and direct a mixture light in a first wavelength band and light in a third wavelength band travel toward the first pixels or the third pixels; and a color filter layer (150) including a first color filter (CF1), a second color filter (CF2), and a third color filter (CF3), wherein the pass bandwidth of the second color filter is greater than the pass bandwidth of each of the first and third color filters.