Color Separating Lens Array for Image Sensor Light Utilization
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Solution Overview
Problem
Image sensors face challenges in light utilization efficiency due to the absorption of unwanted light colors by color filters, leading to reduced light transmission and increased noise, especially with increasing pixel density.
Innovation Solution
The implementation of a color separating lens array (CSLA) on the image sensor substrate, which separates incident light by wavelength using diffraction or refraction characteristics, allowing for improved light condensation onto specific pixels, thereby enhancing light utilization efficiency and reducing crosstalk between adjacent pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a color filter is used to sense light of specific colors, then color detection capability is improved, but light utilization efficiency deteriorates due to absorption of other wavelengths
Solution Approach 1:
The patent replaces the conventional color filter (optical absorption mechanism) with a color separating lens array that uses diffraction and refraction to redirect different wavelengths to different pixels. This substitution eliminates light absorption losses while maintaining color detection capability through spatial separation of wavelengths.
Solution Approach 2:
The color separating lens array acts as an intermediary optical element between the incident light and the pixel array. It mediates the light path by diffracting and refracting different wavelengths at different angles, directing them to appropriate pixels without absorbing the light energy.
2Measurement precision
If pixel density is increased to improve resolution, then measurement precision is improved, but light utilization efficiency deteriorates due to reduced light gathering area per pixel
Solution Approach 1:
The patent segments the incident light into different wavelength components using the color separating lens array, directing each wavelength band to specific pixels. This segmentation allows pixels to receive concentrated light from their designated wavelength range, improving light utilization efficiency even at high pixel densities.
Solution Approach 2:
The color separating lens array provides local quality optimization by directing specific wavelength ranges to specific pixel locations. Each pixel receives optimized light from its corresponding wavelength band, maximizing the light gathering efficiency for each individual pixel while maintaining high overall resolution.
3Loss of energy
If a color separating lens array is used to improve light utilization efficiency, then light transmission is improved, but device complexity increases due to additional optical components
Solution Approach 1:
The color separating lens array performs multiple functions simultaneously: it acts as a diffraction grating to separate wavelengths, a lens to focus light, and a beam director to route light to specific pixels. This multi-functionality reduces the need for separate optical components, thereby limiting the increase in device complexity while achieving improved light transmission efficiency.
4Ease of manufacture
If conventional color filters are used, then manufacturing simplicity is maintained, but light loss increases due to absorption of 2/3 of incident light
Solution Approach 1:
The patent substitutes the absorbing color filter mechanism with a diffractive and refractive lens array system. This substitution maintains manufacturing feasibility through standard semiconductor fabrication processes for creating nanopost structures, while dramatically reducing light loss from 67% absorption to minimal levels through constructive light redirection.
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 significantly improves light utilization efficiency, reduces light loss, and minimizes crosstalk between pixels, enabling the development of high-resolution, ultra-small, and highly sensitive image sensors with reduced noise.
Implementation Method 1
The CSLA may separate the color of incident light by using diffraction or refraction characteristics of light varying depending on a wavelength
Implementation Method 2
The CSLA may separate the color of incident light by using diffraction or refraction characteristics of light varying depending on a wavelength
Implementation Method 3
the CSLA being configured to separate incident light according to wavelength and condense the separated incident light onto the first pixel, the second pixel, the third pixel, and the fourth pixel
Data Source
AI summary
An image sensor includes: a sensor substrate including a first pixel and a second pixel that are each configured to sense light of a first wavelength, and a third pixel and a fourth pixel that are each configured to sense light of a second wavelength; and a color separating lens array (CSLA) provided on the sensor substrate, the CSLA being configured to separate incident light according to wavelength and condense the separated incident light onto the first pixel, the second pixel, the third pixel, and the fourth pixel. The first pixel, the second pixel, the third pixel, and the fourth pixel are provided in a 2×2 arrangement. The light of the first wavelength and the light of the second wavelength have a complementary color relationship.