Light-Splitting Optical Elements for Solid-State Imaging
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Solution Overview
Problem
Conventional solid-state imaging devices face challenges in achieving high optical efficiency and color representation without increasing the number of photosensitive cells, as they either suffer from low optical efficiency due to light-absorbing color filters or require a significant increase in photosensitive cells when using micro mirrors or micro prisms.
Innovation Solution
The use of an array of optical elements with light-splitting functions that split incident light into different wavelength ranges, allowing at least two types of light-splitting elements to be arranged over photosensitive cells to generate multiple color signals without the need for additional photosensitive cells, and calculating color information from the output signals of adjacent cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If light-absorbing color filters are used for color separation, then the device complexity is reduced, but the optical efficiency decreases significantly
Solution Approach 1:
The patent replaces light-absorbing color filters with light-splitting optical elements (prisms or diffraction gratings) that separate wavelengths through refraction or diffraction rather than absorption. This substitution eliminates the fundamental flaw of absorbing filters while maintaining color separation functionality, thereby resolving the contradiction between device simplicity and optical efficiency.
Solution Approach 2:
The patent changes the operating parameter of wavelength separation from absorption-based to refraction/diffraction-based mechanisms. By altering the physical mechanism parameter, the system achieves high optical efficiency without sacrificing color separation capability, resolving the contradiction between structural simplicity and energy loss.
2Loss of energy
If micro mirrors or micro prisms are used for wavelength separation, then the optical efficiency increases, but the device complexity and number of photosensitive cells required increases significantly
Solution Approach 1:
The patent makes each photosensitive cell multi-functional by enabling it to detect multiple wavelengths through the light-splitting optical elements. Instead of requiring separate cells for each wavelength band, a single cell can respond to multiple wavelengths redirected by the optical elements, thereby reducing the total cell count while maintaining high optical efficiency.
Solution Approach 2:
The patent combines the functions of multiple wavelength-dedicated detectors into a single integrated detection system. By merging the detection capabilities through shared photosensitive cells and using optical elements to direct different wavelengths to the same cell, the system reduces complexity while preserving high optical efficiency.
3Measurement precision
If the number of pixels is increased to improve resolution, then the resolution increases, but the light intensity per pixel decreases and sensitivity drops
Solution Approach 1:
The patent ensures continuous and efficient use of incident light by directing all incoming light rays through the light-splitting optical elements to appropriate photosensitive cells. This continuous optical path maximizes light utilization at each pixel, maintaining high light intensity per pixel even as pixel count increases, thereby resolving the contradiction between resolution and sensitivity.
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 approach achieves high optical efficiency and allows for flexible color representation with reduced photosensitive cells, enabling efficient use of both visible and infrared radiation without optical loss.
Implementation Method 1
Each of the light-splitting elements transmits a light ray falling within a first wavelength range toward a direction that defines a first angle with respect to incident light and also transmits a light ray falling within a second wavelength range toward a direction that defines a second angle with respect to the incident light
Implementation Method 2
The light-splitting element includes: a high-refractive-index transparent portion that is made of a material with a relatively high refractive index; and a low-refractive-index transparent portion that is made of a material with a relatively low refractive index
Implementation Method 3
The first photosensitive cell outputs a signal including an electrical signal component that has been produced as a result of reception of the light ray that has been transmitted through the first optical element
Data Source
AI summary
Light-splitting elements are arranged in at least two columns and two rows to form two pairs 1a, 1b and 1c, 1d. Each element splits incident light into light rays and makes them fall on a portion of a photosensing section right under itself and an adjacent photosensitive cell. The element 1a splits the incident light so that a primary color ray C1 and its complementary color ray C1′ enter an adjacent cell 2b and an underlying cell 2a, respectively. The element 1b makes a primary color ray C2 and its complementary color ray C2′ enter an underlying cell 2a and an adjacent cell 2a, respectively. The element 1c does the same as the element 1b. And the element 1d makes a primary color ray C3 and its complementary color ray C3′ enter an adjacent cell 2c and an underlying cell 2d, respectively. These photosensitive cells 2 perform photoelectric conversion, thereby outputting an electrical signal representing the intensity of the incident light. By carrying out simple calculations between the outputs of these cells, a color signal and a luminance signal are generated.