Projector Light Source Optical Path Merging for Speckle Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing light source apparatuses that separate blue light for generating white light through a phosphor and a diffuser plate have separate optical paths, leading to increased size due to the need for additional optical components.
Innovation Solution
A light source apparatus with a wavelength converter that includes a wavelength conversion layer and a reflection film to separate blue light into excitation light and reflected light, combined with a diffusion layer and optical elements to align optical paths, reducing apparatus size and diffusing laser light for reduced speckle noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate optical paths are used for blue light and yellow fluorescence, then light separation and combination can be achieved, but apparatus size increases due to additional optical components
Solution Approach 1:
The patent merges the optical paths of blue light and yellow fluorescence by using a wavelength conversion layer that converts blue light to yellow fluorescence in-situ. The wavelength conversion layer is positioned such that both the incident blue light and the generated yellow fluorescence share the same optical path through the layer, eliminating the need for separate optical paths and additional components like separate mirrors and diffusers. This integration reduces apparatus size while maintaining light separation and combination capabilities.
Solution Approach 2:
The wavelength conversion layer acts as an intermediary that performs both wavelength conversion and optical path unification. By incorporating the wavelength conversion function directly into the optical path structure, the patent eliminates the need for separate optical components that would otherwise be required to handle blue light and yellow fluorescence separately. The wavelength conversion layer serves as a mediator that transforms blue light to yellow fluorescence while maintaining a compact, unified optical path.
2Illumination intensity
If laser light is used as light source, then high coherence and brightness are achieved, but speckle noise and interference fringes increase
Solution Approach 1:
The patent extracts the harmful coherence property of laser light by introducing a wavelength conversion layer that converts the coherent blue laser light to incoherent yellow fluorescence. This extraction process removes the speckle noise and interference fringes associated with coherent light while preserving the high brightness and illumination intensity. The wavelength conversion layer effectively separates the useful illumination function from the harmful coherence property.
Solution Approach 2:
The patent changes the wavelength parameter of the light by converting blue light (445 nm) to yellow fluorescence through the wavelength conversion layer. This parameter change from blue to yellow wavelength region transforms the coherent laser light into incoherent fluorescence, thereby reducing speckle noise and interference fringes while maintaining high illumination intensity. The wavelength conversion process fundamentally alters the coherence properties of the light.
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
The apparatus generates compact white illumination with reduced speckle noise and interference fringes, efficiently using optical paths to minimize size and enhance image quality.
Implementation Method 1
a wavelength converter configured to convert part of the first light into second light having a second wavelength band different from the first wavelength band
Implementation Method 2
a first reflection film provided at the light exiting surface and configured to separate the first light into the part of the first light and the other part of the first light
Implementation Method 3
a diffusion layer configured to diffusively transmit the first light
Data Source
AI summary
A light source apparatus includes a light source configured to output first light; a first optical system that the first light output from the light source enters; a light collection system that the first light passing through the first optical system enters; and a wavelength converter configured to convert part of the first light into second light, the wavelength converter having a light exiting surface on which the first light is incident and through which the second light exits, and a first reflection film configured to separate the first light into the part and the other part, the first optical system includes a first optical element that includes a second reflection film configured to reflect the other part of the first light, and a diffusion layer configured to diffusively transmit the first light, and a second optical element configured to transmit the first light and reflect the second light.