Display Module Optical Member Inclination Correction
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Solution Overview
Problem
Existing virtual image display apparatuses face challenges in miniaturization while maintaining optical performance and resolution, particularly in head-mounted displays, due to the arrangement of optical elements which can lead to increased size and a strange appearance when worn.
Innovation Solution
A display module with a light-guiding optical system and an optical member that corrects the inclination of the light emission surface to reduce aberration on the exit pupil, allowing for miniaturization while ensuring optical performance and resolution, achieved through a temporary assembly and measurement process to adjust the optical member's inclination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optical path is extended to correct aberration using a small number of optical elements, then the resolution is maintained, but the apparatus size increases and miniaturization cannot be achieved
Solution Approach 1:
The patent introduces a meniscus lens with specific curvature radii (R1, R2) and focal length (f1) to change the optical parameters of the system. This lens corrects aberrations by modifying the light path geometry without requiring an extended optical path length, thereby maintaining resolution while enabling miniaturization of the head-mounted display apparatus.
Solution Approach 2:
The meniscus lens acts as an intermediary optical element between the display element and the eyepiece optical system. It mediates the correction of aberrations that would otherwise require a longer optical path, allowing the system to achieve proper image quality in a compact configuration.
2Reliability
If the optical elements are arranged to correct aberration, then the optical performance is improved, but the thickness before and after the optical system increases causing the apparatus to overhang
Solution Approach 1:
By carefully selecting the curvature radii and focal length parameters of the meniscus lens, the patent optimizes the optical path to correct aberrations while minimizing the axial thickness of the system. This allows the apparatus to maintain proper optical performance without excessive overhang that would cause a strange appearance when worn.
3Device complexity
If a small number of optical elements are used, then the device complexity is reduced, but the aberration correction capability is insufficient
Solution Approach 1:
The patent achieves effective aberration correction with a minimal number of optical elements by optimizing the parameters of the meniscus lens. The specific curvature radii and focal length are designed to correct multiple types of aberrations simultaneously, maintaining high optical performance while keeping the system simple and compact.
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 the miniaturization of virtual image display apparatuses while maintaining resolution and reducing aberration, improving the design quality and user experience by adjusting the optical member's inclination to optimize image light incidence angles.
Implementation Method 1
an optical member provided between the display element and a light-emitting portion of the light-guiding optical system, the optical member including a light incidence surface on which the image light emitted from the display element is incident and a light emission surface that emits the image light incident from the light incidence surface
Data Source
AI summary
A display module includes a display element, a light-guiding optical system forming an exit pupil, and an optical member including a light incidence surface and a light emission surface. The light-guiding optical system is an eccentric optical system, and includes first and second incidence areas on which the image light emitted from the light emission surface is incident. The optical member is disposed, correcting an inclination of the light emission surface with respect to the light-guiding optical system such that an variation amount in an incidence angle of the image light with respect to the first incidence area, before and after the light emission surface is inclined, is greater than an variation amount in an incidence angle of the image light with respect to the second incidence area.