Solid-State Imaging Device Dispersive Elements Refraction
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Solution Overview
Problem
Conventional solid-state imaging devices have low light use efficiency due to absorptive color filters, and previous solutions using refractive index varying media for dispersion suffer from decreased efficiency and size limitations due to diffraction effects, making it difficult to miniaturize the devices while maintaining sensitivity.
Innovation Solution
A solid-state imaging device with dispersive elements composed of first and second light transmissive film materials, where the refractive index varies by wavelength, and the volume occupation ratio of these materials changes directionally to guide red, blue, and green light effectively to corresponding light-receiving elements, improving light use efficiency and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If absorptive color filters are used for color separation, then color separation is achieved, but light use efficiency decreases to approximately 25%
Solution Approach 1:
The patent replaces the absorptive color filter system with a refractive dispersion system using dispersive elements. Instead of absorbing unwanted wavelengths, the new system refracts different wavelengths to different angles, directing them to corresponding light-receiving elements. This substitution eliminates the 75% light loss inherent in absorptive filtering while achieving effective color separation through wavelength-dependent refraction.
Solution Approach 2:
The patent changes the optical parameter approach from absorption-based to refraction-based color separation. By utilizing the refractive index properties of dispersive elements, the system redirects different wavelength components of light to different spatial positions, thereby improving light use efficiency while maintaining color separation functionality.
2Loss of energy
If diffraction gratings are used for light dispersion, then light use efficiency is improved, but device size increases due to diffraction periodicity requirements
Solution Approach 1:
The patent substitutes diffraction-based dispersion with refraction-based dispersion. Instead of relying on diffraction gratings that require large periodic structures, the invention uses dispersive elements that achieve wavelength separation through refraction. This substitution enables compact device design while maintaining high light use efficiency, as refraction does not impose the same size constraints as diffraction periodicity.
Solution Approach 2:
The patent changes the physical mechanism from diffraction to refraction for achieving light dispersion. By utilizing the refractive index characteristics of materials rather than diffraction periodicity, the system achieves wavelength-dependent separation without requiring large device dimensions, thereby enabling miniaturization while preserving light use efficiency.
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 significantly increases light use efficiency and sensitivity by reducing light collection loss compared to diffraction-based methods, allowing for higher performance and potential miniaturization without the size constraints of traditional diffraction gratings.
Implementation Method 1
each of the dispersive elements includes: a first light transmissive film material; and a second light transmissive film material with a property of having a refractive index that is lower than a refractive index of the first light transmissive film material in a first wavelength range of the incident light and higher than the refractive index of the first light transmissive film material in a second wavelength range of the incident light
Data Source
AI summary
A solid-state imaging device includes: light-receiving elements; and first dispersive elements on a light-incident side of the light-receiving elements. Each first dispersive element includes first and second light transmissive film materials. The second light transmissive film material has a refractive index that is lower than that of the first light transmissive film material in a first wavelength range and higher than that of the first light transmissive film material in a second wavelength range longer in wavelength than the first wavelength range. A volume occupation ratio of the first light transmissive film material in each dispersive element increases from one end towards the other end of the dispersive element in a direction parallel to a light-receiving surface, while a volume occupation ratio of the second light transmissive film material in the dispersive element increases from the other end towards the one end in the direction.