Projection Device Intermediate Optical System Speckle Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Projection apparatuses using coherent light sources face issues with speckle generation, leading to brightness unevenness and increased power consumption due to the need for mechanical rotation of scattering plates, which also results in a larger apparatus size and inefficient light utilization.
Innovation Solution
The introduction of an intermediate optical system that restricts the diffusion angle of coherent light beams, allowing for telecentric design of the light modulator side of the projection optical system, thereby reducing speckle visibility and enhancing illumination intensity while simplifying the system and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a scattering plate is rotated mechanically to reduce speckles, then speckle visibility is reduced, but the apparatus size increases and power consumption increases
Solution Approach 1:
The patent replaces the mechanical rotation system with an optical solution using a diffuser plate positioned at a specific location in the optical path. The diffuser plate creates multiple scattered light paths without requiring mechanical movement, thereby eliminating motors, sensors, and control systems while effectively reducing speckle visibility through optical diffusion.
Solution Approach 2:
The patent introduces a diffuser plate as an intermediary element in the optical path between the light source and the projection lens. This diffuser plate mediates the light propagation by creating multiple scattered paths that interfere destructively to reduce speckle patterns, without requiring direct mechanical manipulation of the optical components.
2Object-affected harmful factors
If a scattering plate is rotated mechanically to reduce speckles, then speckle visibility is reduced, but power consumption increases
Solution Approach 1:
The patent eliminates the need for electrical power by replacing the motor-driven rotation system with a passive optical diffuser plate. The diffuser plate operates without any energy input, relying solely on the optical properties of the material to scatter light and reduce speckle patterns, thereby reducing power consumption to zero for this function.
3Duration of action of stationary object
If coherent light sources are used, then lifecycle is extended and system size is reduced, but speckle generation occurs
Solution Approach 1:
The patent converts the harmful coherent nature of laser light into a beneficial effect by using a diffuser plate to create controlled scattering. The coherence of the laser light, which causes speckle, is transformed into a uniform scattered illumination pattern where multiple coherent paths interfere to reduce speckle visibility, turning the laser's coherent property from a disadvantage into an advantage for achieving both long lifecycle and low speckle.
4Volume of stationary object
If coherent light sources are used, then system size is reduced, but speckle generation occurs
Solution Approach 1:
The patent introduces a diffuser plate as a compact intermediary element that fits within the existing optical path without requiring additional space for mechanical rotation mechanisms. This thin optical component effectively reduces speckle by creating multiple scattered light paths while maintaining the compact system size enabled by coherent light sources.
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 effectively minimizes speckle patterns, improves illumination intensity, and reduces the size and power consumption of the projection apparatus, while maintaining high-quality image display.
Implementation Method 1
coherent light beams incident on respective positions of the hologram recording medium 55 are diffracted by the hologram recording medium 55, thereby spreading, to illuminate the entire region of the illumination region LZ
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A projection apparatus has an optical device configured to be capable of diffusing coherent light beams, an irradiation unit configured to irradiate the coherent light beams to the optical device so that the coherent light beams scan the optical device, a light modulator that is illuminated by coherent light beams incident on and diffused at respective points of the optical device from the irradiation unit, a projection optical system configured to project a modulated image generated by the light modulator onto a scattering plane, and an intermediate optical system provided between the optical device and the light modulator, configured to restrict an diffusion angle of coherent light beams diffused by the optical device.