Projection Display System Supplementary Light Utilization
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Solution Overview
Problem
The prior art in projection display systems experiences low utilization rates of supplementary light sources, such as red and green light sources, due to scattering, incomplete collection, and loss in the non-projection light path, leading to increased costs and inefficiencies.
Innovation Solution
A projection display system that combines the first image light and supplementary image light using a light combining device after modulation, where the beam cross-sectional area of the first image light is greater than that of the supplementary image light, and the projection lens system images and overlaps the combined lights at a predetermined position, thereby minimizing light loss and improving utilization rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a red supplementary light source is added to increase the red component in the combined light, then the white balance problem is solved, but the light utilization rate of the red light source becomes low (about 60-70%) due to scattering, incomplete collection, and loss in the non-projection light path
Solution Approach 1:
The patent segments the light path into two separate modulation systems: one for the first light (blue excitation light + yellow phosphor) and one for the supplementary light (red light source). Each system independently modulates its light source according to image data, avoiding the mixing and scattering problems that caused low utilization rates in the prior art. The segmented approach allows each light path to be optimized separately for maximum efficiency.
Solution Approach 2:
The patent introduces a light combining device as an intermediary that merges the first image light and supplementary image light after they have been separately modulated. This intermediary component enables the combination of two independently optimized light paths without the scattering and collection losses that occurred when supplementary light was mixed with the main light path earlier in the optical system.
2Illumination intensity
If the green light component is filtered out to return the white balance point to the Planck black body curve, then the white balance problem is solved, but the light extraction efficiency of the white light source is lowered
Solution Approach 1:
The patent extracts the green light component issue from the main white light generation path by using a separate supplementary light source system. Instead of filtering out green light from the yellow phosphor emission, the invention adds controlled amounts of red light through a separate modulation path, thereby adjusting white balance without removing any light components and maintaining full light extraction efficiency.
3Device complexity
If the red light is transmitted via the central region of the light splitting filter into the non-projection light path, then the light path is simplified, but the red light losses about 10% due to being transmitted into the non-projection light path
Solution Approach 1:
The patent inverts the traditional approach by not trying to integrate the supplementary light into the existing light splitting filter system, but rather by creating a separate modulation system for the supplementary light that combines with the main light path after modulation. This reversal eliminates the need for the supplementary light to pass through the light splitting filter, thereby eliminating the 10% loss that occurred when red light was transmitted into the non-projection light path.
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 approach enhances the utilization rate of supplementary light sources, reducing costs and improving the efficiency of the projection display system by directly utilizing the supplementary light for image display and avoiding inconsistent light distribution issues.
Implementation Method 1
a blue-violet laser light to excite yellow phosphor to obtain a white light. However, an emission spectrum of the yellow phosphor at present is weak in the red color segment
Implementation Method 2
The central region of the light splitting filter 13 transmits a blue light and a red light and reflects a green light
Implementation Method 3
reflected and then concentrated by the light condensing lens 15 to be incident on the light homogenizing device 16
Data Source
Figure 1~2
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Figure 5~6
AI summary
A projection display system (10), comprising: a first light source (111), used for emitting a first light; a first light modulation system (121), used for receiving the first light and modulating the first light into a first image light; a supplementary light source (112), used for at least emitting a supplementary light, wherein a spectrum of the first light comprises a spectrum of the supplementary light; a second light modulation system (122), used for receiving the supplementary light and modulating the supplementary light into a supplementary image light; a light combining device (130), positioned on emission light paths of the first light modulation system (121) and the second light modulation system (122) and used for combining the first image light and the supplementary image light, the beam cross-sectional area of the first image light being greater than the beam cross-sectional area of the supplementary image light at the light combining position; and a projection lens system (150), positioned on light-emitting paths of the first light modulation system (121) and the second light modulation system (122) and used for causing the first image light and the supplementary image light to form coincident images at a predetermined position (140). The supplementary light source of the projection display system (10) has a high utilization rate.