Polarized LED Light Source for Projection Displays
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Solution Overview
Problem
Projection-type display devices face challenges with high-pressure mercury lamps due to environmental concerns, short service life, and limited brightness adjustment, while white LEDs have fixed emission spectra and reduced light utilization efficiency due to constraints on etendue and color balance.
Innovation Solution
A light source device utilizing a first light source emitting P-polarized white light and a second light source emitting S-polarized red or green light, combined using polarizing dichroic mirrors to synthesize and adjust colors, enhancing light utilization efficiency and allowing for independent adjustment of color components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a high-pressure mercury lamp is used as a white light source, then high luminance is achieved, but environmental harm increases and service life decreases
Solution Approach 1:
The patent replaces the high-pressure mercury lamp with multiple LEDs that have longer service lives and are environmentally friendly. Although individual LEDs have shorter lifetimes than mercury lamps, the overall system achieves extended operational life through modular replacement and maintains environmental sustainability.
Solution Approach 2:
The patent changes the light source from a mercury-based discharge lamp to solid-state LED technology, fundamentally altering the physical and chemical parameters of the light generation process to eliminate mercury usage and reduce environmental harm while maintaining high luminance output.
2Illumination intensity
If a high-pressure mercury lamp is used as a white light source, then high luminance is achieved, but service life decreases
Solution Approach 1:
The patent divides the single high-pressure mercury lamp into multiple individual LED components. This segmentation allows each LED to operate independently with optimized parameters, and enables modular replacement of individual units, thereby extending the overall service life of the light source system while maintaining high luminance output.
3Use of energy by moving object
If a white LED is used to emit white light, then light-emission efficiency is improved, but white balance adjustment capability is lost
Solution Approach 1:
The patent segments the white light emission into multiple individual LED chips emitting different wavelengths (blue, cyan, green, yellow-green, yellow, orange, red). This segmentation enables independent control of each wavelength component, allowing precise adjustment of white balance and color temperature while maintaining the high light-emission efficiency of LED technology.
Solution Approach 2:
The patent implements dynamic control of each LED chip's emission intensity through independent current regulation. This allows the white balance and color temperature to be adjusted in real-time according to application requirements, transforming the static emission characteristic of conventional white LEDs into a dynamically adjustable system.
4Measurement precision
If color filters are used to extract primary colors from white LED light, then color image display is achieved, but light utilization efficiency decreases
Solution Approach 1:
The patent extracts and eliminates the need for yellow light elimination filters by directly incorporating yellow-light-emitting LED chips into the system. This approach takes out the problematic yellow wavelength component generation step and replaces it with direct yellow LED emission, thereby maintaining color accuracy while significantly improving light utilization efficiency by eliminating the filter-related energy loss.
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 solution improves light utilization efficiency and color balance in projection-type display devices, enabling brighter images with flexible white balance and reduced power consumption.
Implementation Method 1
a first light source that emits light of a plurality of colors including different wavelengths of a first polarization; a light source means that emits light of a second polarization whose polarization state differs from that of the first polarization
Implementation Method 2
a color synthesis means that synthesizes the light of the first polarization that is emitted from the first light source and light of the second polarization that is emitted from the light source means
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A light source device includes: a first light source (3a) that emits first polarized light of a plurality of colors including different wavelengths; a second light source (3b) that emits second polarized light whose polarization state differs from that of the first polarized light and that includes light of at least one color from among the plurality of colors; and a first color synthesis optical element (1) that synthesizes the first polarized light emitted from the first light source (3a) and the second polarized light emitted from the second light source (3b).