Laser Lighting Unit Synchronizing Oscillation to Reduce Speckle Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing projection technologies using laser light sources suffer from speckle noise due to the coherence of the light, which is not effectively addressed by existing solutions that either lack control over the semiconductor laser or high-speed shutter mechanisms, leading to poor image quality and increased costs.
Innovation Solution
A lighting unit that incorporates a sync unit, frequency/phase control unit, pulse generation unit, light source driving unit, and oscillation unit to modulate the laser light source and diffusion filter, ensuring the laser is only active during desired oscillation velocities, thereby reducing speckle noise by synchronizing the light emission with the oscillation of the diffusion filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a diffusion element is used to distribute and diffuse coherent light from a laser source, then speckle noise is reduced, but the device complexity increases due to additional oscillation control mechanisms
Solution Approach 1:
The diffusion element is oscillated at a specific frequency range (10-1000 Hz) during laser light emission to dynamically change the light distribution pattern, reducing speckle noise through temporal variation rather than static diffusion structures
Solution Approach 2:
The oscillation of the diffusion element is performed periodically at controlled frequencies, creating time-varying diffusion patterns that reduce speckle noise while maintaining system simplicity through regular cyclic motion rather than complex random vibration mechanisms
2Device complexity
If the oscillation frequency and amplitude of the diffusion element are reduced, then the cost and complexity of the oscillation unit are reduced, but the effectiveness of speckle noise reduction may be compromised
Solution Approach 1:
Specific parameter ranges are defined for oscillation frequency (10-1000 Hz) and amplitude (0.1-10 mm) to optimize the balance between speckle noise reduction effectiveness and oscillation unit simplicity, allowing cost-effective implementation while maintaining performance
3Object-affected harmful factors
If the laser light source is controlled to emit light only during desired oscillation velocities, then speckle noise is further reduced, but the device complexity increases due to additional control units
Solution Approach 1:
A control system synchronizes laser light emission with the oscillation state of the diffusion element, activating the laser only when the diffusion element moves at desired velocities, thereby reducing speckle noise through coordinated control rather than independent operation of each component
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 reduces the recognizability and spatial movement of speckle noise, allowing for a more uniform and reduced noise component on the observer's retina, while also reducing the oscillation frequency and amplitude, leading to a cost-effective and high-performance projection display.
Implementation Method 1
a diffusion filter for distributing and diffusing coherent light incident from a semiconductor laser by changing its intensity distribution to a predetermined intensity distribution
Implementation Method 2
oscillation means for oscillating the diffusion filter at a specific frequency and amplitude
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A lighting unit that optimizes an oscillation frequency for oscillating a diffusion device and its amplitude amount and a projecting display using the lighting unit are provided. Driving of a light source driving unit (4) is controlled on the basis of driving of the oscillation driving unit (8).