Electrophoretic Light Control for AR Glasses Illuminance
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Solution Overview
Problem
Existing head-mounted display (HMD) systems for augmented reality struggle to provide high contrast images in bright environments while consuming excessive power and failing to optimize light control based on surrounding illuminance.
Innovation Solution
A display apparatus with a glasses-type frame and an image display device featuring an electrophoretic light control device, which includes two transparent substrates and electrodes, and an illuminance sensor to adjust light transmittance and image brightness according to environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a liquid crystal shutter is used to control external light, then the amount of external light incident on the image display device can be controlled, but power consumption increases and half the amount of external light is blocked using the polarizing plate
Solution Approach 1:
The patent extracts the light control function from the traditional liquid crystal shutter and polarizing plate combination, implementing it directly in the optical device where light guidance occurs. This eliminates the need for separate shutter mechanisms and reduces power consumption while maintaining effective external light control.
Solution Approach 2:
The optical device is designed to perform multiple functions: guiding light from the image display element, controlling external light incident on the display, and managing overall light transmission. This multi-functionality eliminates the need for separate dedicated shutter components, reducing system complexity and power consumption.
2Illumination intensity
If a liquid crystal shutter with polarizing plate is used to control external light, then light transmittance can be adjusted, but half the amount of external light is blocked
Solution Approach 1:
The patent introduces an illuminance sensor as an intermediary that detects environmental light conditions and enables the control unit to adjust the optical device accordingly. This allows the system to optimize light transmission dynamically, preventing unnecessary blocking of external light while maintaining image quality.
Solution Approach 2:
The system transitions from static light control (fixed polarizing plate) to dynamic control where the optical device adjusts light transmission based on real-time illuminance sensor feedback. This dynamic adjustment optimizes external light utilization across varying environmental conditions.
3Device complexity
If existing HMD systems are used in bright environments, then the device structure is simple, but high contrast images cannot be provided
Solution Approach 1:
The patent implements a feedback control system where the illuminance sensor continuously monitors environmental light conditions and provides feedback to the control unit. This enables real-time adjustment of the optical device to maintain high image contrast across varying brightness conditions without significantly increasing system complexity.
Solution Approach 2:
The system dynamically changes optical parameters (light transmission characteristics) based on environmental illuminance levels. The control unit adjusts the optical device parameters in response to sensor feedback, optimizing image contrast for different lighting conditions while maintaining a relatively simple overall device structure.
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 high contrast images, reduces power consumption, and optimizes the observation state by effectively controlling external light based on environmental illuminance, enhancing user experience in varying lighting conditions.
Implementation Method 1
a light control device that adjusts an amount of external light incident from outside, wherein the light control device includes two transparent substrates, electrodes, and an electrophoretic dispersion liquid
Implementation Method 2
an illuminance sensor to adjust light transmittance and image brightness according to environmental conditions
Implementation Method 3
a collimating optical system that converts light emitted from the pixels of the image forming device into parallel light
Implementation Method 4
a light guide plate in which incident light propagates while being totally reflected
Data Source
AI summary
A display apparatus includes: (i) a glasses-type frame that is mounted on the head of an observer; and (ii) an image display device that is attached to the frame, wherein the image display device includes (A) an image forming device, and (B) an optical device on which light emitted from the image forming device is incident, in which the light is guided, and from which the light is emitted, a light control device that adjusts an amount of external light incident from the outside is provided in a region of the optical device from which light is emitted, and the light control device includes two opposite transparent substrates, electrodes that are provided on the substrates, and an electrophoretic dispersion liquid that is sealed between the two substrates.