Digital Micro-Mirror Device Stuck Mirror Detection via Test Pathway
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Solution Overview
Problem
Conventional digital micro-mirror devices lack real-time integrity testing during display cycles, making it difficult to detect stuck micro-mirrors, which is critical for applications requiring high display integrity like head-up or head-down displays.
Innovation Solution
A display apparatus that includes a digital micro-mirror device with a test image pathway and a measurement arrangement to compare electromagnetic radiation levels with a predetermined value, allowing for real-time detection of stuck micro-mirrors without interfering with the desired image, using separate optical paths and sources to generate and measure the test image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a digital micro-mirror device is used for display, then image projection capability is achieved, but real-time integrity testing is not possible making stuck micro-mirrors undetectable
Solution Approach 1:
The patent divides the optical path into separate test and display pathways. The test pathway includes a test light source, test beam splitter, and test detector that operate independently from the main display pathway. This segmentation allows integrity testing to be performed without interfering with normal display operations, resolving the contradiction between reliability monitoring and device complexity.
Solution Approach 2:
The patent implements preliminary integrity testing by continuously monitoring the test pathway before display operations. The test system checks for stuck micro-mirrors in advance and during operation, allowing the system to detect and report integrity issues before they affect the main display function, thus improving reliability without significantly increasing complexity.
2Difficulty of detecting and measuring
If a test pathway is added to monitor micro-mirror integrity, then detection capability is improved, but device complexity increases
Solution Approach 1:
The patent extracts the integrity testing function into a separate, dedicated test pathway with its own light source and detector. This extraction allows the test system to be developed and optimized independently from the main display system, improving detection capability while managing complexity through modular design. The test pathway can be added without fundamentally redesigning the core display architecture.
Solution Approach 2:
The patent designs the test pathway components to serve multiple functions where possible. For example, the test beam splitter is integrated into the existing optical architecture, and the same micro-mirror array serves both display and testing functions. This multi-functionality approach improves detection capability while minimizing the increase in overall device complexity.
3Reliability
If continuous testing is performed, then reliability monitoring is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic testing rather than truly continuous testing. The test light source operates in pulsed or periodic cycles, performing integrity checks at regular intervals during display operation. This periodic action maintains real-time monitoring capability while significantly reducing energy consumption compared to continuous operation of the test light source.
Solution Approach 2:
The patent applies partial testing action by monitoring only the test pathway components and using the test pathway to infer the state of the entire system. Rather than continuously testing all display components, the system uses the test pathway as a representative sample, achieving reliable monitoring with reduced energy expenditure through partial system monitoring.
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 real-time monitoring and detection of stuck micro-mirrors, ensuring the integrity of the display by generating a test image that does not interfere with the desired image, thus maintaining accuracy and reliability.
Implementation Method 1
Each micro-mirror element is arranged to reflect electromagnetic radiation within one of at least two pathways for generating a desired image and one of the at least two pathways for generating a test image
Implementation Method 2
at least one electromagnetic radiation measurement arrangement associated with at least one of the at least two pathways and arranged to measure electromagnetic radiation associated with the test image on that pathway
Data Source
Figure 1~3a
Figure 3b~4
Figure 5~6a
AI summary
A display apparatus (20) includes an electromagnetic radiation source (22) and digital micro-mirror device (21) having a plurality of micro-mirror elements on a surface thereof. The electromagnetic radiation source (22) is arranged to illuminate the digital micro-mirror device (21) and at least one micro-mirror element of the digital micro-mirror device (21) either reflects electromagnetic radiation along a primary path (23) to an exit lens (23) to form a desired image to be viewed by an operator or along a secondary path (25) to an electromagnetic radiation dump (26). The digital micro-mirror device (21) is also operable to generate a test image at the electromagnetic radiation dump (26) at a predetermined time. An electromagnetic radiation measurement arrangement (27) is arranged along the secondary path (25), between the digital micro-mirror device (21) and the radiation dump (26), to measures a luminance value of electromagnetic radiation representing the test image reflected by the digital micro-mirror device (21) and an associated comparator processor compares the measured luminance with an ideal luminance for the test image.