Image Sensor Beam Splitter for Light Efficiency
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Solution Overview
Problem
Existing image sensors with organic dye color filters suffer from significant light energy loss due to absorption of all but one wavelength band, resulting in low light efficiency and reduced color vividness.
Innovation Solution
The implementation of a photoelectric conversion layer with a color filter, a low refractive index layer, and beam splitters that extend diagonally across the pixel area, including high refractive index portions for red and blue sub-pixels, to split and direct light more efficiently, reducing absorption and enhancing light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If an organic dye color filter is used to transmit desired color spectrum components, then color selection is achieved, but light energy loss increases and light efficiency decreases
Solution Approach 1:
The color filter layer is segmented into multiple regions (red, green, blue sub-pixels) with each region having optimized optical properties. The beam splitter further segments the incident light into different wavelength components, directing them to appropriate photoelectric conversion elements, thereby reducing overall light energy loss while maintaining color selection capability.
Solution Approach 2:
Different regions of the color filter layer are designed with different optical characteristics tailored to their specific function. The beam splitter introduces localized optical elements with specific refractive indices in different areas to optimize light transmission and reduce energy loss in each region, thereby improving overall light efficiency.
2Illumination intensity
If an organic dye color filter absorbs all but one wavelength band, then color purity is improved, but light efficiency is reduced
Solution Approach 1:
The beam splitter acts as an intermediary optical element that precedes the color filter layer. It pre-separates incident light into different wavelength components and directs them to corresponding sub-pixel regions, reducing the absorption burden on the color filter and improving both light efficiency and color reproduction capability.
3Loss of energy
If a color filter layer is used in all pixel areas, then color information is captured, but light absorption increases
Solution Approach 1:
The color filter layer is segmented such that it is removed from the green sub-pixel area while being retained in red and blue sub-pixel areas. This segmentation allows green light to pass through without absorption, reducing overall light absorption while color information is still captured through the beam splitter's wavelength separation and the retained color filter regions.
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 improves light efficiency and produces more vivid colors by increasing the irradiance of red and blue light on their respective sub-pixels, while maintaining or adjusting green light distribution, thereby enhancing image quality and color purity.
Implementation Method 1
a beam splitter included in the low refractive index layer... Refractive indexes of the high refractive index portions may be higher than a refractive index of the low refractive index layer
Data Source
AI summary
An image sensor and a method of manufacturing the same are provided. The image sensor includes a photoelectric conversion layer; a color filter disposed on the photoelectric conversion layer; a low refractive index layer disposed on the color filter; a beam splitter disposed within the low refractive index layer; and a lens layer disposed on the low refractive index layer and covering the beam splitter. The beam splitter extends in a diagonal direction of a pixel area of the color filter, in a plan view.