Spatial Light Modulator Inspection via Shift Amount Analysis
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Solution Overview
Problem
Spatial light modulators, such as GLV, face challenges in maintaining uniform light reflection due to deterioration over time, requiring frequent reacquisition of IV characteristic information for each modulating unit, which is labor-intensive and time-consuming, especially when the number of units is large, and lacks effective indices to quantify deterioration.
Innovation Solution
An inspecting device that applies voltages to modulating units to control light amounts, detects reflected light, and calculates shift amounts in driving values to assess deterioration, allowing for efficient reacquisition of IV characteristic information and storage of shift history to determine necessary reanalysis or maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If IV characteristic information is reacquired for each modulating unit periodically, then the light reflection uniformity is maintained, but the labor and time required increases greatly when the number of modulating units is large
Solution Approach 1:
The patent replaces manual measurement methods with an automated optical detection system. A laser beam is radiated onto the modulating units, and a line sensor detects the reflected light distribution. This automated optical system continuously monitors the light reflection uniformity without human intervention, resolving the contradiction between maintaining reliability and reducing time loss.
Solution Approach 2:
The inspection system operates continuously during the operation of the spatial light modulator. The laser beam and line sensor work continuously to monitor the light reflection uniformity of all modulating units, enabling real-time detection without interrupting the normal operation. This continuous monitoring maintains reliability while minimizing the time required for inspection.
2Measurement precision
If IV characteristic information is reacquired for each modulating unit individually, then accurate deterioration assessment is achieved, but the labor required increases greatly
Solution Approach 1:
The patent merges the inspection of multiple modulating units into a single operation. The line sensor detects the light reflection distribution across all modulating units simultaneously, and the control unit processes the combined data to assess deterioration of individual units. This merging approach maintains measurement precision while dramatically reducing the labor required compared to individual inspections.
Solution Approach 2:
The system uses optical copying to create a visual representation of the light reflection distribution from all modulating units. The line sensor captures the reflected light pattern, which is then processed to generate information about each individual unit's condition. This optical copying method enables accurate individual assessment without manual intervention for each unit.
3Manufacturing precision
If high power laser beam is radiated on GLV to achieve fine drawing, then drawing fineness is enhanced, but the load on GLV increases causing faster deterioration
Solution Approach 1:
The patent implements a feedback mechanism where the light reflection uniformity is continuously monitored and fed back to the control unit. Based on this feedback, the system can detect early signs of deterioration in individual modulating units and adjust operation accordingly. This feedback loop enables the system to maintain drawing fineness while managing the load on GLV to extend its durability.
Solution Approach 2:
The inspection system performs preliminary detection of deterioration before it significantly impacts performance. By continuously monitoring light reflection uniformity, the system can identify modulating units that are beginning to deteriorate and take preventive measures, such as adjusting voltage or replacing specific units, before they cause failures that would compromise drawing quality or require complete system shutdown.
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 efficient inspection and maintenance of spatial light modulators by quantifying deterioration and reducing the time and labor required for reacquiring IV characteristic information, allowing for timely determination of when to reanalyze or replace units based on accumulated shift amounts.
Implementation Method 1
a voltage is applied to a movable ribbon configuring the movable reflecting surface in each modulating unit so that the movable reflecting surface is moved to a recessed position with respect to the fixed reflecting surface
Implementation Method 2
a laser beam is radiated onto a plurality of modulating units 321 of the spatial light modulator 32, and light reflected from the modulating units is detected
Data Source
AI summary
A spatial modulator is configured by arranging a plurality of modulating units in an X-axis direction, the modulating units each including at least one light modulating element having a fixed reflecting surface with a constant height from a base surface and a movable reflecting surface with a variable height from the base surface. The spatial modulator spatially modulates a laser beam by the plurality of modulating units. A driver circuit unit applies a voltage corresponding to a driving value to each of the plurality of modulating units, to drive the modulating units individually. A shift amount acquiring portion acquires a driving value at a reference time point and a driving value at an inspecting time point which correspond to a specific light amount value, and acquires a differential value thereof as a shift amount.