HMD Light Receiving Device for Wavelength Drift Detection
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Solution Overview
Problem
Existing image display devices in head-mounted displays (HMDs) face challenges in detecting abnormalities and wavelength variations of the light source, leading to reduced image quality due to dirt on the light guide plate or degradation of the light source, and heat-induced wavelength changes.
Innovation Solution
Incorporating a light receiving device that detects light output from the image forming device, allowing for immediate detection of abnormalities and wavelength changes, with the ability to control the wavelength of the light source based on detection results, using a configuration that includes a light guide plate, polarizing units, and a light semi-reflecting member to ensure accurate image display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If a light guide plate is used to guide light from the image forming device, then the device weight and size can be reduced, but the light guide plate may get dirty or degrade over time, reducing image quality and making it difficult to detect abnormalities
Solution Approach 1:
The patent incorporates a light receiving device that continuously monitors the light output from the image forming device before it reaches the observer. This preliminary detection mechanism captures abnormalities such as dirt accumulation or light source degradation early, enabling timely correction without affecting the compact light guide plate design
Solution Approach 2:
The system establishes a feedback loop where the light receiving device detects light intensity variations and transmits this information to the control device. The control device then adjusts the light source output or notifies the user, creating a closed-loop system that maintains image quality while preserving the lightweight structure
2Productivity
If the light source operates continuously, then image display functionality is maintained, but heat generation causes wavelength changes that degrade image quality
Solution Approach 1:
The light receiving device continuously monitors the wavelength of light output from the image forming device. When heat-induced wavelength drift is detected, the control device adjusts the light source parameters or activates cooling mechanisms, creating a feedback-controlled system that maintains optimal wavelength despite continuous operation and heat generation
Solution Approach 2:
The system dynamically adjusts operating parameters of the light source based on detected wavelength variations. By changing current, voltage, or other control parameters in response to temperature-induced wavelength shifts, the system maintains stable light output characteristics while continuing continuous operation
3Device complexity
If no light receiving device is incorporated, then the device complexity is reduced, but abnormalities and wavelength changes cannot be detected
Solution Approach 1:
The light receiving device serves multiple functions: detecting light intensity abnormalities, measuring wavelength variations, and providing feedback for control. This multi-functional component adds minimal complexity while simultaneously addressing multiple detection requirements, making the addition of detection capability highly efficient
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 high-accuracy detection of image display abnormalities and wavelength changes, allowing for real-time adjustments to maintain image quality and compensate for distortions or intensity reductions, thereby improving the reliability and performance of the image display.
Implementation Method 1
a light guide plate configured to propagate light output from the image forming device
Implementation Method 2
a first polarizing unit configured to polarize the light incident on the light guide plate so that the light incident on the light guide plate is totally reflected inside the light guide plate, and a second polarizing unit configured to polarize light propagating inside the light guide plate according to total reflection
Data Source
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AI summary
There is provided an image display device including (A) an image forming device, (B) an optical device configured to receive incident light output from the image forming device and output the incident light, and (C) a light receiving device configured to detect the light output from the image forming device.