HMD Light Guide Plate Dynamic Switching for Image Accuracy
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Solution Overview
Problem
Semi-transmissive image display apparatuses struggle to accurately view composite images of external objects combined with additional information due to interference from ambient light, while non-transmissive apparatuses prevent observation of external objects altogether.
Innovation Solution
A head-mounted display (HMD) with an image display apparatus that includes an image forming device, an optical device for guiding light, and a dimming device to adjust ambient light levels, allowing for reduced ambient light in one mode to enhance image accuracy and enabling both semi-transmissive and non-transmissive viewing modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a semi-transmissive image display apparatus is used to view composite images of external objects combined with additional information, then the hands are free and smooth movement is possible, but the viewing accuracy deteriorates due to interference from ambient light
Solution Approach 1:
The patent applies dynamics by making the light guide plate's light guide function controllable - it can switch between guiding ambient light (for external object observation) and guiding displayed image light (for composite image viewing). This dynamic switching resolves the contradiction by adapting the system's light guide properties to the current viewing mode, eliminating ambient light interference when accuracy is needed while maintaining hands-free operation.
Solution Approach 2:
The patent changes the light guide plate's optical parameters dynamically. By controlling whether the light guide plate guides light or not (changing its light guide property parameter), the system can eliminate ambient light interference during composite image display while maintaining semi-transmissive functionality for external object observation, thus resolving the accuracy vs. ease of operation contradiction.
2Measurement precision
If a non-transmissive image display apparatus is used to eliminate ambient light interference, then image viewing accuracy is improved, but the ability to observe external objects deteriorates
Solution Approach 1:
The light guide plate dynamically switches between two states: guiding ambient light to the observer's eye (enabling external object observation) and not guiding light (enabling accurate composite image viewing). This dynamic adaptability resolves the contradiction by providing both transmissive and non-transmissive modes as needed.
Solution Approach 2:
The light guide plate serves multiple functions: it can guide ambient light for external object observation and can also be controlled to not guide light for accurate composite image display. This multi-functionality allows the single apparatus to achieve both high accuracy viewing and external object observation capability, resolving the contradiction.
3Adaptability or versatility
If the light guide plate always guides light for external object observation, then adaptability is improved, but image viewing accuracy deteriorates due to ambient light interference
Solution Approach 1:
The system dynamically adjusts the light guide plate's light guide property based on the current viewing mode. When composite image display is active, the light guide plate is controlled to not guide light, eliminating ambient light interference and improving accuracy. When external object observation is needed, it resumes light guiding, providing viewing mode flexibility without sacrificing accuracy.
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
Enables clear, high-accuracy viewing of composite images without ambient light interference and allows observation of external objects in both semi-transmissive and non-transmissive modes, improving usability in various environments.
Implementation Method 1
a light guide plate 121 which causes the incident light to propagate through total reflection and to be emitted
Implementation Method 2
a first deflection unit 130 (for example, formed of a single-layer light reflection film) which reflects the light incident to the light guide plate 121 such that the light incident to the light guide plate 121 is totally reflected inside the light guide plate 121
Implementation Method 3
a collimating optical system 112 which converts light emitted from the pixels of the image forming device 111 into parallel light
Data Source
Figure 1
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Figure 3A~3B
AI summary
A head-mounted display device including an image display apparatus configured to display a captured image of a portion of an environment viewable through the head-mounted display device; and a dimmer configured to, while the captured image is displayed, allow a portion of ambient light from the environment to pass through the dimmer. Also, a method of displaying information on a head-mounted display device. The method may include displaying a captured image of a portion of an environment viewable through the display device; and dimming ambient light received through the head-mounted display device from the environment while displaying the captured image.