Light Control Device for Head-Mounted Display Dimmer
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Solution Overview
Problem
Existing head-mounted display devices face issues with providing high contrast and comfortable viewing experiences when the external light conditions change rapidly, leading to unpleasant feelings and potential eye strain due to sharp adjustments in light transmittance by liquid crystal shutters, which also increase device weight and quality issues.
Innovation Solution
A display device with a light control system that identifies changes in external light and controls dimmer transmittance after a predetermined time, using a light guide plate and a dimmer with a light control device to manage light transmittance based on measured light changes, reducing eye strain and maintaining image quality while minimizing weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a liquid crystal shutter is used to control light transmittance in response to rapid external light changes, then light transmittance control is achieved, but sharp adjustments cause unpleasant feelings and eye strain
Solution Approach 1:
The patent implements dynamic control of the liquid crystal shutter by adjusting its light transmittance based on the rate of change of external light conditions. When light changes rapidly, the shutter responds more quickly; when light changes slowly, the shutter adjusts more gradually. This dynamic response characteristic matches the natural adaptation speed of human eyes, reducing eye strain while maintaining effective light transmittance control.
2Adaptability or versatility
If a liquid crystal shutter is added to control light transmittance, then light control capability is improved, but device weight increases
Solution Approach 1:
The patent optimizes the liquid crystal shutter parameters by selecting materials and design specifications that achieve the required light transmittance control range (from fully transparent to partially translucent) with minimal weight. The control unit is designed to operate the shutter only when necessary, reducing overall system weight requirements while maintaining full light control capability when needed.
3Speed
If light transmittance is adjusted sharply in response to rapid light changes, then rapid adaptation to light conditions is achieved, but image quality deteriorates
Solution Approach 1:
The control unit dynamically adjusts the liquid crystal shutter's light transmittance based on the rate of change of external light conditions. When light changes rapidly, the shutter responds more quickly to maintain image quality; when light changes slowly, the shutter adjusts more gradually. This dynamic response characteristic matches the natural adaptation speed of human eyes, reducing eye strain while maintaining effective light transmittance control.
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 provides a comfortable viewing experience with high contrast and optimized image observation states, even under varying illumination conditions, while simplifying the device structure and reducing weight.
Implementation Method 1
an optical device (light guide unit) 120 on which the parallel light converted in the collimating optical system 112 is incident, in which the light is guided, and from which the light is emitted. The optical device 120 includes a light guide plate 121 in which incident light propagates while being totally reflected
Implementation Method 2
the first diffraction grating member 330 and the second diffraction grating member 340 are reflective volume hologram diffraction gratings provided on the light guide plate 321
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
A display device comprising a first image display device comprising a light guide plate, a dimmer, and a light control device. The light control device is configured to identify a start time of change in quantity of light received by the display device, and control transmissivity of the dimmer based on quantity of light received by the display device, after a predetermined amount of time after the start time has elapsed.