Projection Display Device Laser Defect Detection
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Solution Overview
Problem
Existing projection display devices struggle to detect and prevent defects in the light diffusion unit, which can lead to inadequate laser light diffusion and eye strain for viewers.
Innovation Solution
A projection display device that uses a second laser light to detect the state of the light diffusion unit's incident and emission surfaces, allowing for the determination of defects and immediate termination of the projection process to prevent eye strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only detachment detection is implemented, then the light diffusion unit detachment can be detected, but defects such as damage in the predetermined region cannot be detected
Solution Approach 1:
The detection unit is designed to perform multiple functions: detecting both detachment of the light diffusion unit and defects such as damage in the predetermined region. By making the detection unit universal, the patent avoids adding separate detection systems while enhancing defect detection capability.
Solution Approach 2:
The detection unit provides feedback about the state of the light diffusion unit (detachment and defects) to the control unit, which then adjusts the projection operation accordingly. This feedback mechanism enables reliable defect detection while maintaining system simplicity through integrated control.
2Productivity
If the projection continues with a defective light diffusion unit, then productivity is maintained, but eye strain occurs due to improper laser light diffusion
Solution Approach 1:
The detection unit performs preliminary detection of defects in the light diffusion unit before projection continues. By detecting defects such as damage in the predetermined region in advance, the system can prevent eye strain by stopping projection before harmful conditions develop, while maintaining productivity when no defects are present.
Solution Approach 2:
The patent converts the potentially harmful situation (defective light diffusion unit continuing operation) into a beneficial outcome by using the detection unit to identify defects and trigger appropriate responses. This transforms what would be a harmful continuous operation into a protected operation that prevents eye strain while maintaining productivity when safe.
3Measurement precision
If comprehensive defect detection is implemented, then all defects can be detected, but the device complexity increases
Solution Approach 1:
The detection unit is configured to specifically detect defects in the predetermined region of the light diffusion unit, which is the critical area affecting projection quality and eye safety. By focusing detection precision on this specific local region rather than implementing comprehensive detection throughout the entire unit, the patent achieves high measurement precision while controlling device complexity.
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
Effectively prevents eye strain by reliably detecting defects in the light diffusion unit and stopping the projection process when necessary, ensuring proper laser light diffusion.
Implementation Method 1
a light source that emits a laser light for displaying a projection
Implementation Method 2
a drive reflection unit that reflects the laser light emitted from the light source and performs scanning with the laser light
Implementation Method 3
a light diffusion unit including a predetermined region in which the laser light used in the scanning by the drive reflection unit is diffused
Implementation Method 4
the light detection unit detects the second laser light that reflects a state of an incident surface of the light diffusion unit in the predetermined region, or a state of an incident surface and an emission surface of the light diffusion unit in the predetermined region, and an internal state of the light diffusion unit in the predetermined region
Data Source
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AI summary
A projection display device includes: a light source 2 that emits a first laser light L1 for displaying a projection and a second laser light L2 for inspection; a scanning drive mirror 3 that reflects the first laser light L1 and the second laser light L2 emitted from the light source 2, and uses the first laser light L1 and the second laser light L2 in scanning; a light diffusion unit 4 that includes a predetermined region R that allows the first laser light L1 used in the scanning by the scanning drive mirror 3 to be transmitted through the predetermined region R, and diffuses the first laser light L1; a light detection unit 6 that detects the second laser light L2 that passed the predetermined region R of the light diffusion unit 4; and a control unit 8 that executes a process to detect the second laser light L2, and determines a state of the predetermined region R of the light diffusion unit 4 on the basis of a detection value of the light detection unit 6. In a case where the control unit 8 determines that a defect occurs in the predetermined region R of the light diffusion unit 4 as the state of the predetermined region R of the light diffusion unit 4, the control unit 8 executes a process to stop displaying the projection.