Diffraction Optical Member Color Separation Correction
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Solution Overview
Problem
Existing virtual image display apparatuses suffer from significant color separation and are often bulky and heavy, with safety concerns due to direct laser irradiation of the retina and inefficient light use due to multiple diffraction elements.
Innovation Solution
A virtual image display apparatus featuring a diffraction optical member with a light transmissive substrate that corrects color separation produced by the diffraction section, allowing for high-definition color display without increasing the size of the optical system, using a light transmissive substrate with high transmittance to counteract color separation caused by both refraction and diffraction, and incorporating a lens system to adjust image light for improved quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a diffraction optical element is used to guide light in a virtual image display apparatus, then the optical path can be controlled and images can be formed, but color separation is produced which degrades image quality
Solution Approach 1:
A light transmissive substrate is introduced as an intermediary component between the diffraction optical element and the viewer's eye. This substrate corrects the color separation produced by diffraction through its refractive properties, allowing the harmful effect to be compensated without removing the useful diffraction function.
Solution Approach 2:
The refractive index of the light transmissive substrate is carefully selected and adjusted to match specific requirements for correcting color separation. By changing the optical parameters of the substrate material, the patent achieves precise compensation for the wavelength-dependent angular deviations caused by diffraction.
2Adaptability or versatility
If multiple diffraction elements are used to enlarge light flux width, then the optical system can achieve broader viewing angles, but light use efficiency decreases and the system becomes more complex
Solution Approach 1:
The light transmissive substrate performs multiple functions simultaneously: it acts as a structural support for the diffraction optical element, provides optical compensation for color separation, and contributes to light flux enlargement. This multi-functionality eliminates the need for separate components, reducing system complexity and improving light efficiency.
Solution Approach 2:
The patent combines the diffraction optical element and the light transmissive substrate into an integrated structure where the substrate supports the diffraction pattern. This merging of components reduces the number of optical interfaces and minimizes light loss while achieving both color separation correction and light flux enlargement.
3Measurement precision
If a holographic optical element is used for color separation, then wavelength-dependent light guidance can be achieved, but the system requires complex color separation correction mechanisms
Solution Approach 1:
The light transmissive substrate serves as a simple intermediary that passively corrects color separation through refraction, eliminating the need for complex active correction mechanisms. The substrate's refractive index is chosen to naturally compensate for the wavelength-dependent angular deviations, providing a straightforward solution to a complex problem.
4Measurement precision
If the optical system is designed to correct color separation through additional components, then image quality improves, but the system size increases which contradicts compact design requirements
Solution Approach 1:
The color separation correction function is merged into the light transmissive substrate that already exists as a structural component of the diffraction optical element. By integrating the correction function into an existing component rather than adding a separate element, the patent achieves color separation correction without increasing system size.
Solution Approach 2:
The light transmissive substrate is designed to perform multiple functions: structural support, optical compensation for color separation, and light flux management. This multi-functionality allows a single component to achieve what would traditionally require multiple separate elements, maintaining compact system size while improving image quality.
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 effectively corrects color separation without increasing the system's size, achieving high-definition color display and ensuring safety by reducing the risk of laser exposure, while maintaining a compact and lightweight design.
Implementation Method 1
a diffraction section that directs orientation of image light based on diffraction toward a position of a viewer's eye
Implementation Method 2
the light transmissive substrate is a color separation correcting section that corrects color separation produced by the diffraction section
Data Source
AI summary
A virtual image display apparatus includes a diffraction optical member including a diffraction section that directs the orientation of image light based on diffraction toward the position of a viewer's eye and a light transmissive substrate that is disposed in the diffraction section and on the side facing the eye and supports the diffraction section, and an image forming section that outputs the image light toward the diffraction optical member, and the light transmissive substrate is a color separation correcting section that corrects color separation produced by the diffraction section.