Laser Diode Actuation Device for Adaptive Speckle Reduction
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Solution Overview
Problem
Laser projection systems using semiconductor lasers face challenges in effectively suppressing speckle patterns, which degrade the optical quality of projected images, and existing solutions require manual adjustments based on production and operational parameters.
Innovation Solution
An actuation device generates a high-frequency modulated signal for the laser diode, regulated by an evaluation circuit that adjusts the signal based on detected light intensity to achieve adaptive speckle reduction, allowing for independent regulation of speckle suppression and adjustment according to projected data types and ambient conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a high-frequency modulated actuation signal is applied to the laser diode for speckle suppression, then the speckle patterns are reduced, but the light intensity emitted by the laser diode varies and requires manual adjustment
Solution Approach 1:
The patent implements a feedback control system where a photo diode detects the light intensity emitted by the laser diode and feeds this information back to an evaluation circuit. The evaluation circuit processes the intensity signal and generates a control signal that automatically adjusts the actuation signal to the laser diode, eliminating the need for manual adjustment while maintaining optimal speckle suppression
Solution Approach 2:
The system performs self-regulation by automatically detecting its own output light intensity and adjusting its actuation signal accordingly. The laser diode system monitors its own performance through the photo diode and evaluation circuit, and autonomously corrects any deviations in light intensity without external intervention
2Object-affected harmful factors
If the high-frequency modulated actuation signal is regulated based on production and operational parameters, then speckle suppression can be optimized, but the device complexity increases
Solution Approach 1:
The patent employs a feedback mechanism where the photo diode continuously monitors the light intensity and the evaluation circuit automatically processes this information to adjust the actuation signal. This closed-loop control system optimizes speckle suppression dynamically without requiring complex manual regulation mechanisms or multiple separate control systems
Solution Approach 2:
The evaluation circuit serves multiple functions: it receives the intensity signal from the photo diode, processes this information, generates the control signal for speckle suppression, and regulates the actuation signal accordingly. By combining these functions in a single integrated circuit, the patent reduces overall device complexity while achieving effective speckle suppression
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
This solution enables dynamic and adaptive speckle reduction, improving the visual quality of projected images by adjusting the degree of suppression based on emitted brightness and projected content, independent of production variances and operational parameters.
Implementation Method 1
a photo diode, which is set up to detect the intensity of the light emitted by the laser diode
Implementation Method 2
Laser diodes generate structured patterns of different brightness in a viewer's eye when coherent light impinges on an optically rough surface
Implementation Method 3
the wave fronts reflected into different directions interfere with one another
Data Source
AI summary
An actuation device for a laser diode includes: a first driver device which is set up to generate a high-frequency modulated actuation signal and to feed the signal into the laser diode for speckle suppression, and an evaluation circuit, which is coupled with the first driver device, and which is set up to output to the first driver device an intensity signal indicating the intensity of the light emitted by the laser diode and a control signal as a function of the intensity signal in order to regulate the high-frequency modulated actuation signal.