Multiplexing Reflection Mirror for Laser Projection
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Solution Overview
Problem
Existing light source apparatuses using laser light sources face challenges in suppressing unevenness in brightness and speckle noise in projected video images, which are difficult to address with simple configurations.
Innovation Solution
A light source apparatus and projection display system incorporating a multiplexing reflection mirror with a partial reflection coating and a total reflection coating, inclined to direct emission light from laser sources, which splits and combines light fluxes to reduce brightness unevenness and speckle noise through a diffuser.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a laser light source is used, then high brightness and color purity are achieved, but brightness unevenness and speckle noise occur in the projected image
Solution Approach 1:
The light flux from the laser source is divided into multiple separate light fluxes using the multiplexing reflection mirror with partial reflection coating. By splitting the coherent laser light into multiple paths and subsequently combining them, the patent reduces the coherence effects that cause speckle noise and brightness unevenness, while maintaining the high brightness advantage of laser sources.
2Object-affected harmful factors
If a complex optical system is used to reduce brightness unevenness and speckle noise, then image quality improves, but device complexity increases
Solution Approach 1:
The patent combines the functions of light splitting and light combining into a single multiplexing reflection mirror component. This mirror has a partial reflection coating that simultaneously performs both functions in one optical element, significantly simplifying the overall optical system compared to using separate beam splitters and combiners, while still effectively reducing brightness unevenness and speckle noise.
Solution Approach 2:
The multiplexing reflection mirror serves multiple functions: it acts as a beam splitter, a beam combiner, and a light path director all in one component. This multi-functional design reduces the number of optical elements needed in the system, lowering complexity while maintaining the ability to suppress speckle noise and brightness unevenness.
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 solution effectively reduces brightness unevenness and speckle noise in projected images while maintaining a simple configuration, enhancing image quality and cost-effectiveness.
Implementation Method 1
a first surface on which a partial reflection coating having a predetermined reflectance is formed
Implementation Method 2
a second surface on which a total reflection coating is formed
Data Source
AI summary
A light source apparatus and a projection display apparatus according to the present disclosure include: a laser light source; and a multiplexing reflection mirror having a first surface on which a partial reflection coating having a predetermined reflectance is formed, and a second surface on which a total reflection coating is formed, the first surface and the second surface being opposite to each other and formed in a parallel flat shape. The multiplexing reflection mirror is disposed so as to incline toward an optical path of an emission light from the laser light source such that the emission light is incident from first surface.