Electrochromic Dimming Layer Moisture Retention for HMD Contrast
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Solution Overview
Problem
Existing dimming devices for head-mounted displays face issues with color change failure due to moisture disappearance in the electrochromic material layer, leading to insufficient contrast in bright environments or when content is displayed.
Innovation Solution
Incorporating a moisture-retaining layer and a water vapor transmissive transparent substrate in the dimming device, along with a water vapor barrier layer, to maintain moisture levels and prevent color change failure, while using an electrochromic material layer with a laminated structure of electrodes and electrolyte layers for controlled light shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dimming layer is constituted by an electrochromic material and light transmittance is changed by applying a color change of a substance generated by a redox reaction, then the dimming device can control light transmittance, but if moisture disappears in the dimming layer, a phenomenon that a color change does not occur occurs
Solution Approach 1:
A gel layer is introduced as an intermediary component between the electrolyte layer and the electrochromic material layer. This gel layer serves as a moisture reservoir that supplies water to the electrolyte layer during electrochromic reactions, preventing moisture loss from the dimming layer and ensuring reliable color change operation over time
Solution Approach 2:
The gel layer is designed with a porous structure that allows it to absorb and retain moisture while enabling the transport of ions and water molecules to the electrolyte layer. This porous structure facilitates continuous moisture supply to maintain the electrochromic material's functionality without compromising the structural integrity of the dimming device
2Ease of operation
If a head mounted display is used to present visual information, then hands are not occupied and mobility is maintained, but in bright environments or depending on content, sufficient contrast cannot be imparted to the virtual image
Solution Approach 1:
The dimming device incorporates an electrochromic material layer that dynamically adjusts its light transmittance properties in response to electrical signals. This dynamic control allows the device to adapt to varying environmental lighting conditions and content requirements, optimizing virtual image contrast while maintaining hands-free operation and mobility benefits
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 effectively suppresses color change failure, ensuring consistent contrast and image quality by maintaining moisture levels and utilizing an electrochromic material layer for controlled light shielding, enhancing the reliability and performance of the dimming device.
Implementation Method 1
light transmittance is changed by applying a color change of a substance generated by a redox reaction of the electrochromic material
Implementation Method 2
a dimming layer constituting a dimming device is constituted by an electrochromic material and light transmittance is changed by applying a color change of a substance generated by a redox reaction of the electrochromic material
Implementation Method 3
incorporating a moisture-retaining layer and a water vapor transmissive transparent substrate in the dimming device, along with a water vapor barrier layer, to maintain moisture levels
Implementation Method 4
along with a water vapor barrier layer, to maintain moisture levels and prevent color change failure
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
An image display device includes: an image forming device; an optical device 120, 320 having a virtual image forming region where a virtual image is formed on the basis of light emitted from the image forming device; and a dimming device 700 for adjusting the amount of external light incident from the outside, disposed so as to face the virtual image forming region and to be away from the optical device. The dimming device 700 includes: a transparent protective substrate 720 on which external light is incident; a dimming layer 710 formed on a surface of the protective substrate 720 facing the optical device 120, 320; and a moisture-retaining layer 730 formed on the dimming layer 710.