Dynamic Diffusion Plate for Laser Speckle Reduction
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Solution Overview
Problem
Projection display apparatuses face challenges in achieving a small size, wide color gamut, and high luminance while eliminating speckle noises and fine unevenness in luminance, particularly due to the use of coherent laser light sources.
Innovation Solution
The implementation of a light source device featuring solid-state light sources emitting blue, green, and red light, combined using dichroic mirrors and diffused by a dynamic diffusion plate and a first diffusion plate, which reduces speckle noises and luminance unevenness, allowing for a compact and efficient projection display apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If solid-state light sources (laser) are used to achieve high luminance and wide color gamut, then luminance and color gamut are improved, but speckle noises and fine unevenness in luminance occur due to high coherence
Solution Approach 1:
The patent employs a dynamic diffusion plate that rotates to change the diffusion state of light dynamically. This rotation modulates the coherence of the laser light, effectively reducing speckle noises while preserving the high luminance and wide color gamut characteristics of the solid-state light sources.
Solution Approach 2:
The patent introduces a diffusion plate as an intermediary element between the solid-state light sources and the optical system. This diffusion plate scatters the coherent laser light, reducing speckle formation while allowing the system to maintain high luminance output through proper optical design.
2Ease of manufacture
If conventional light source configurations are used, then ease of manufacture is maintained, but device size becomes large and cost increases
Solution Approach 1:
The patent merges multiple optical functions into a compact integrated light source device. The solid-state light sources, dichroic mirrors for color combination, and diffusion plate are combined in a unified structure that achieves high luminance and wide color gamut in a small form factor, reducing both device size and manufacturing complexity.
Solution Approach 2:
The patent changes the physical parameters of the light source system by using solid-state light sources with specific wavelength characteristics and optimizing the diffusion plate parameters. This allows achieving high luminance and wide color gamut while maintaining a compact device size and simplifying the manufacturing process.
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 configuration results in a small-size projection display apparatus with a wide color gamut and high luminance, effectively eliminating speckle noises and luminance unevenness, while maintaining polarization characteristics and reducing the size and cost of the light source device.
Implementation Method 1
a plurality of dichroic mirrors that combine the blue light, the green light, and the red light having exited from the solid-state light sources
Implementation Method 2
a first diffusion plate on which the combined light having been combined by the plurality of dichroic mirrors is incident; a dynamic diffusion plate that is disposed at a position at which the combined light having exited from the first diffusion plate converges and starts to diverge
Data Source
AI summary
The light source device of the projection display apparatus according to the present disclosure includes: solid-state light sources that individually emit blue light, green light, and red light; a plurality of dichroic mirrors that combine the blue light, the green light, and the red light having exited from the solid-state light sources; a first diffusion plate on which the combined light having been combined by the plurality of dichroic mirrors is incident; a dynamic diffusion plate that is disposed at a position at which the combined light having exited from the first diffusion plate converges and starts to diverge.