Optical Measurement Device for HMDs with Telecentric Emission
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Solution Overview
Problem
Existing optical characteristic measurement devices, such as those described in WO2017-183582, fail to accurately measure the optical characteristics of head-mounted displays (HMDs) due to a lack of adjustment mechanisms for focal length, leading to potential inaccuracies in evaluating the optical performance of virtual image display devices.
Innovation Solution
An optical measurement device is designed with a first and second optical member configured for telecentric emission, a light reception member aligned with these members, and an adjusting mechanism to form an image on the light reception surface, allowing for adjustments in the light path to accommodate varying focal lengths and simulate the human pupil, thereby enabling accurate optical characteristic measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed optical measurement device is used without focal length adjustment mechanism, then the device structure is simple, but the measurement precision for HMDs with varying focal lengths deteriorates
Solution Approach 1:
The patent introduces a movable member that can shift the image sensor and diaphragm position along the optical axis, transforming the fixed optical measurement device into a dynamic one. This enables adjustment of the focal length to match different HMD configurations, thereby improving measurement precision without significantly increasing structural complexity
Solution Approach 2:
The patent changes the parameter of focal length by moving the image sensor and diaphragm to different positions along the optical axis. This parameter adjustment allows the measurement device to accommodate HMDs with varying focal lengths, resolving the contradiction between simple device structure and high measurement precision
2Ease of operation
If the image sensor and diaphragm are fixed at a specific position, then the device operation is simple, but the adaptability to different HMD focal lengths deteriorates
Solution Approach 1:
The patent makes the image sensor and diaphragm movable along the optical axis rather than fixed, allowing the device to adapt to different HMD focal lengths. The movable member can be adjusted to different positions, providing versatility while maintaining ease of operation through straightforward positioning mechanisms
3Device complexity
If no light path adjustment mechanism is provided, then the device complexity is low, but the measurement precision for different focal lengths deteriorates
Solution Approach 1:
The patent introduces a movable member that dynamically adjusts the light path by shifting the image sensor and diaphragm position. This dynamic adjustment capability allows precise measurement of optical characteristics for HMDs with varying focal lengths while keeping the overall device complexity manageable through a straightforward mechanical adjustment mechanism
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
This configuration allows for precise measurement of optical characteristics of HMDs by adjusting the light path to match the focal length of the virtual image display device, ensuring accurate evaluation while minimizing variations in image size, thus overcoming the limitations of previous measurement devices.
Implementation Method 1
a second optical member where the light emitted from the first optical member is incident, the second optical member being configured to emit, with telecentricity, the incident light
Implementation Method 2
an adjusting member configured to adjust a light path so as to form an image of light received at a light reception surface of the light reception member
Data Source
AI summary
A first optical member where image light from a virtual image display device as a measurement target is incident, the first optical member being configured to emit incident image light, a second optical member where the image light emitted from the first optical member is incident, the second optical member being configured to emit, with telecentricity, incident image, a light reception member disposed along a first direction in which the first optical member and the second optical member are disposed side by side, and the light reception member being configured to receive the image light emitted from the second optical member, and an adjusting member configured to adjust a light path so as to form an image of image light received at a light reception surface of the light reception member, are provided.