Two-Stage Diaphragm for Ghosting Suppression in Virtual Image Displays
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Solution Overview
Problem
Existing virtual image display apparatuses, such as head-mounted displays, face challenges in achieving a wide field angle while minimizing the optical system size and preventing ghosting issues, especially when a diaphragm is only provided at one location.
Innovation Solution
A virtual image display apparatus with a two-stage structural diaphragm, comprising a first diaphragm and a second diaphragm positioned differently based on the inclinations of principal rays in various directions, effectively adjusts the light to suppress ghosting and maintain high image quality, allowing for a more compact optical system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a single diaphragm is provided in the projection optical system, then the device complexity is reduced, but the ability to suppress ghosting is insufficient
Solution Approach 1:
The diaphragm structure is divided into two separate diaphragms (first diaphragm and second diaphragm) positioned at different locations in the optical system. Each diaphragm has a specific aperture size designed to address different aspects of ghosting, allowing for more effective suppression of ghost images while maintaining manageable device complexity through modular design.
Solution Approach 2:
The two diaphragms act as intermediary elements that selectively block stray light paths responsible for ghosting. By positioning them at different locations with different aperture sizes, they mediate the light propagation to prevent ghost image formation without completely blocking the useful imaging light.
2Volume of moving object
If the optical system is miniaturized, then the head-mounted display size is reduced, but the field angle becomes limited
Solution Approach 1:
The invention optimizes specific parameters including the aperture sizes of the two diaphragms and their positions within the compact optical system. By carefully adjusting these parameters, the system achieves a balance between miniaturization and maintaining an adequate field angle, allowing the optical system to be small while still providing sufficient viewing angle.
3Volume of moving object
If the optical system is miniaturized, then the head-mounted display size is reduced, but ghosting suppression becomes more difficult
Solution Approach 1:
Dividing the diaphragm into two separate components allows each to be optimally positioned and sized within the compact optical system. This segmentation enables effective ghosting suppression even in a miniaturized configuration, as each diaphragm can be strategically placed to block specific ghosting paths without requiring a larger overall system.
Data Source
AI summary
Provided are an imaging element configured to display an image, a projection optical system configured to project an image from the imaging element, and a two-stage structural diaphragm including a first diaphragm forming a first aperture portion in the projection optical system, and a second diaphragm forming a second aperture portion in the projection optical system, in which inclinations of a principal ray, relative to an image plane of an imaging element, of imaging light emitted from a peripheral portion of the image plane differ between in a first direction and in a second direction perpendicular to the first direction among in-plane directions of the image plane, in which the first diaphragm and the second diaphragm in the two-stage structural diaphragm are provided at different positions corresponding to differences between the inclinations of the principal ray in the first direction and in the second direction.