Projection Light Source Optics for Uniform RGB Beam Combining
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Solution Overview
Problem
Existing projection display apparatuses using solid-state light sources face challenges in achieving high uniformity and color accuracy due to differences in light flux sizes and outputs among red, green, and blue laser light sources, leading to increased device size and luminance unevenness.
Innovation Solution
A light source device comprising red, green, and blue solid-state light sources, combined using polarizing mirrors and beam splitting elements to equalize light flux sizes, ensuring high uniformity and efficiency while reducing device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If light flux splitting elements (prism array or mirror array) are used to equalize light flux sizes of red, green, and blue light beams, then uniformity of projected image is improved, but device size increases
Solution Approach 1:
The patent combines the light flux splitting function and color beam combining function into a single integrated optical system. The beam splitting element divides the blue light flux while the dichroic mirrors simultaneously combine all three color beams (red, green, blue) into a unified optical path, eliminating the need for separate prism arrays or mirror arrays and thereby reducing device size while maintaining uniformity.
Solution Approach 2:
The dichroic mirrors perform multiple functions: they act as beam combining elements for different color wavelengths while also serving as light flux equalizing elements. The same optical components that combine the color beams also control and equalize the light flux sizes, reducing the number of dedicated components needed and compacting the overall device structure.
2Illumination intensity
If different numbers of red, green, and blue laser light sources are used to achieve desired brightness and white chromaticity, then color accuracy is improved, but luminance unevenness and color unevenness occur
Solution Approach 1:
The patent changes the optical parameters (light flux size, beam diameter, intensity distribution) of the individual color beams through the beam splitting element and dichroic mirrors. By adjusting these optical parameters, the system equalizes the contribution of each color beam to the final white light output, ensuring uniform luminance and color distribution across the projected image while maintaining the required brightness and chromaticity.
3Manufacturing precision
If light flux sizes of color light beams are equalized by beam splitting element, then uniformity is improved, but device complexity increases
Solution Approach 1:
The patent merges the beam splitting function and beam combining function into a single integrated optical train. The beam splitting element for blue light and the dichroic mirrors for color combination are arranged in series to form a unified system that performs multiple functions simultaneously, reducing the number of separate components and simplifying the overall optical architecture while achieving light flux equalization.
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 achieves a small-size, high-luminance projection display apparatus with a wide color gamut by equalizing light flux sizes, eliminating luminance and color unevenness, and enhancing image quality.
Implementation Method 1
a second polarizing mirror that combines the red light emitted from the red solid-state light source and the green light emitted from the green solid-state light source
Implementation Method 2
a beam splitting element that splits the blue light emitted from the blue solid-state light source into transmitted light transmitting the beam splitting element and reflected light reflected on the beam splitting element
Data Source
AI summary
A light source device includes a red solid-state light source that emits red light, a green solid-state light source that emits green light, a blue solid-state light source that emits blue light, a second polarizing mirror that combines the red light emitted from the red solid-state light source with the green light emitted from the green solid-state light source, and a beam splitting element that splits the blue light emitted from the blue solid-state light source into transmitted light transmitting the beam splitting element and reflected light reflected on the beam splitting element, and transmits or reflects the combined red light and green light.