Holographic Light Modulation Element for Chromatic Dispersion Control
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Solution Overview
Problem
Existing light modulation elements using Fourier-transformed holograms suffer from chromatic dispersion when irradiated with white light, leading to rainbow-colored optical images that reduce visual perception, especially for small images representing letters or symbols.
Innovation Solution
A light modulation element comprising an optical member with a light control part that reflects or absorbs light in a predetermined wavelength while passing other wavelengths, and a light transmitter that allows light in the visible range to pass through, thereby controlling the color of the reproduced optical image when observed with a point light source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a Fourier-transformed hologram is irradiated with white light including a plurality of wavelength components, then an optical image can be reproduced, but chromatic dispersion occurs causing rainbow colors that reduce visual perception
Solution Approach 1:
The patent applies local quality by making different parts of the optical member have different spectral transmission characteristics. Specifically, the optical member is designed to transmit light in a first wavelength range (e.g., blue-green region) while absorbing or reflecting light in a second wavelength range (e.g., red region), creating localized spectral filtering that eliminates chromatic dispersion in the reproduced image while maintaining visual perception.
Solution Approach 2:
The patent changes the spectral transmission parameters of the optical member by introducing wavelength-selective transmission properties. The optical member transitions from transmitting all visible wavelengths to selectively transmitting only specific wavelength ranges, thereby controlling the color composition of the reproduced optical image and eliminating rainbow effects caused by chromatic dispersion.
2Area of moving object
If the size of the reproduced optical image is small, then space is saved, but visual perception is reduced due to rainbow colors from chromatic dispersion
Solution Approach 1:
By implementing wavelength-selective transmission in specific regions of the optical member, the patent enhances the visual perception of small reproduced images. The local spectral filtering ensures that even small images free from chromatic dispersion maintain high visual clarity and color accuracy, allowing compact design without sacrificing perceptibility.
3Loss of information
If letters or symbols are reproduced with rainbow colors, then information is conveyed, but correct recognition is impaired
Solution Approach 1:
The patent changes the spectral composition parameter of the reproduced image by filtering out wavelength ranges that cause chromatic dispersion. This results in monochromatic or limited-color reproduced images where letters and symbols maintain consistent color across different regions, enabling accurate recognition while preserving information transmission.
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 enables visual perception of a reproduced optical image with a desired color, reducing chromatic dispersion and improving clarity, which enhances the recognition of letters, symbols, and other images.
Implementation Method 1
a light control part that reflects or absorbs light in a predetermined wavelength and passes through light in other than the predetermined wavelength
Implementation Method 2
a light transmitter 1b that passes through light in at least the visible light range
Data Source
Figure 1~2
Figure 3A~3C
Figure 4~5C
AI summary
A light modulation element comprising an optical member is provided. The optical member comprises: a light control part to reflect light in a predetermined wavelength and to transmit light in other than the predetermined wavelength in light in at least a visible light range in accordance with a reproduction reference image for reproducing an original image; and a light transmissive part to transmit light in at least the visible light range including the predetermined wavelength, wherein the optical member comprises a hologram recording layer, and the light control part is an interference fringe in the hologram recording layer, and wherein the optical member makes an observer visually perceive a reproduced optical image of a color of the predetermined wavelength when a point light source is observed through a predetermined region including the interference fringe in the hologram recording layer from a normal direction to the optical member in a state where light in a predetermined wavelength range including the predetermined wavelength is incident from the point light source on the predetermined region, and makes an observer visually perceive a reproduced optical image of a color of a shorter wavelength than the predetermined wavelength when the point light source is observed through the predetermined region from a direction oblique to the normal direction.