Image Sensor Dispersive Element for High Sensitivity Resolution
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Solution Overview
Problem
Conventional techniques for capturing color components in image sensors either result in low optical efficiency or require a large number of photosensing sections, failing to achieve high sensitivity and resolution effectively.
Innovation Solution
A solid-state image sensor with a dispersive element array that splits incoming light into multiple wavelength ranges, allowing each photosensitive cell to capture light across different color ranges, enabling high sensitivity and resolution with a minimal number of pixels through computational processing of photoelectrically converted signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional color filters are used to capture color components, then the structure is simple, but optical efficiency decreases because each filter absorbs two out of three color components
Solution Approach 1:
The patent segments the color filtering function across multiple layers: a first color filter layer captures one color component while transmitting others, and a second color filter layer captures additional color components. This segmentation allows different parts of the optical path to perform specialized functions, improving overall optical efficiency by reducing light absorption losses compared to single-layer filters.
Solution Approach 2:
The patent introduces a reflective layer as an intermediary between the two color filter layers. This reflective layer redirects transmitted light from the first filter to the second filter, enabling the system to capture multiple color components without requiring all filters to simultaneously block all non-target wavelengths, thereby improving optical efficiency.
2Measurement precision
If the number of pixels is increased to improve resolution, then resolution increases, but light intensity per pixel decreases leading to lower sensitivity
Solution Approach 1:
The patent makes photosensitive cells multi-functional by enabling each cell to capture multiple color components through the two-layer filter system. Instead of requiring separate pixels for different color functions, a single pixel can gather information across multiple wavelength ranges, maintaining sensitivity while supporting high-resolution imaging.
Solution Approach 2:
The patent ensures continuous utilization of incident light by having the first color filter layer transmit non-absorbed wavelengths to the second color filter layer, which then captures them. This continuous action maximizes light utilization at each pixel, maintaining high sensitivity even as pixel density increases for higher resolution.
3Loss of energy
If dichroic mirrors are used to improve optical efficiency, then optical efficiency increases, but device complexity increases due to multiple mirrors and lenses
Solution Approach 1:
The patent replaces complex, expensive dichroic mirrors with simpler, more manufacturable color filter layers that can be deposited using standard semiconductor fabrication techniques. While color filters have limitations, they provide a cost-effective and manufacturable solution that achieves good optical efficiency without the complexity of multiple precision optical elements.
Solution Approach 2:
The patent changes the approach from using reflective dichroic mirrors with specific wavelength-selective parameters to using transmissive color filter layers with different absorption characteristics. This parameter change simplifies the optical system structure while maintaining the ability to separate and capture multiple color components efficiently.
4Area of moving object
If micro lenses are added to increase aperture ratio, then aperture ratio increases, but optical efficiency still decreases due to color filter absorption
Solution Approach 1:
The patent applies preliminary action by having the first color filter layer perform initial wavelength selection before light reaches the photosensitive cell. This preliminary filtering allows the system to optimize subsequent light paths, enabling better utilization of transmitted light and improving overall optical efficiency even with micro lenses present.
Solution Approach 2:
The patent adds a vertical dimension to color filtering by stacking two color filter layers at different positions in the optical path. This dimensional approach allows the system to capture multiple color components through depth rather than requiring lateral separation, improving optical efficiency while working effectively with the micro lens 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
The solution achieves high sensitivity and resolution without optical loss, allowing for effective color image capture with a pixel shifted arrangement using a minimal number of pixels.
Implementation Method 1
a dispersive element array, in which a number of dispersive elements are arranged for some of the photosensitive cells
Implementation Method 2
The photosensitive cell array outputs photoelectrically converted signals corresponding to the incident light
Data Source
AI summary
A color representation technique to be effectively applicable to a pixel shifted arrangement to realize high sensitivity and high resolution is provided by using a dipersive prism or diffraction.A dispersive element is provided for an image sensor in which photosensitive cells are arranged to be shifted from each other by a half pitch both horizontally and vertically. The dispersive element makes at least G rays fall straight down to a pixel right under itself and also makes either R rays or B rays incident on an adjacent pixel. Meanwhile, a photosensitive cell, for which no dispersive element is provided, receives directly incident light, too. Color information can be obtained by making computations on photoelectrically converted signals provided by these pixels.