Multi-Wavelength LED Illumination Unit for Projector Luminance Balance
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Solution Overview
Problem
Conventional projector illumination units using high-luminance discharge lamps are large and consume significant power, and solid-state light-emitting devices like LEDs and OLEDs are sought for their size and power advantages, but they face challenges in achieving balanced luminance due to varying light emission intensities of primary colors.
Innovation Solution
The illumination unit incorporates multiple light sources with solid-state light-emitting devices that emit light in different wavelength bands, allowing for adjustment of relative light emission intensities, and includes a traveling-direction angle conversion device and integrator with fly-eye lenses to optimize light distribution and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If solid-state light-emitting devices (LED, OLED) are used instead of discharge lamps, then size and power consumption are reduced, but light emission intensity balance among primary colors deteriorates
Solution Approach 1:
The illumination unit divides the light source into multiple independent solid-state light-emitting devices (first, second, and third light sources), each emitting different wavelength bands. This segmentation allows independent control and optimization of each light source's emission characteristics, enabling compensation for inherent intensity imbalances among primary colors while maintaining the energy efficiency benefits of solid-state devices.
2Illumination intensity
If multiple light sources with different wavelength bands are used, then luminance of illumination light is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple solid-state light-emitting devices emitting different wavelength bands (blue, green, red) into a unified illumination unit with integrated optical paths. By merging these light sources and their control systems into a single compact structure, the design achieves high luminance through multi-wavelength emission while minimizing the increase in device complexity compared to separate systems.
3Stability of the object's composition
If light emission intensity of each primary color is adjusted individually, then white balance is improved, but control complexity increases
Solution Approach 1:
The illumination unit utilizes parameter changes in the drive currents supplied to each solid-state light-emitting device to adjust light emission intensities. By varying current parameters independently for each wavelength band (blue, green, red), the system achieves precise white balance control and luminance optimization without requiring complex mechanical or optical adjustment mechanisms, keeping the control system relatively simple.
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 configuration enhances the luminance of illumination light by allowing for precise adjustment of light emission intensities and improves light use efficiency, enabling better white balance and reduced power consumption.
Implementation Method 1
a plurality of light sources each including a solid-state light-emitting device configured to emit light from a light emission region
Implementation Method 2
a traveling-direction angle conversion device and an integrator with fly-eye lenses to optimize light distribution
Data Source
AI summary
An illumination unit includes a plurality of light sources each including a solid-state light-emitting device configured to emit light from a light emission region including a single or a plurality of light-emitting spots. The solid-state light-emitting device includes a single chip or a plurality of chips each emitting light beam. Three or more of the light-emitting spots are provided within the whole light sources, to allow the whole light sources to emit light beams in two or more wavelength bands different from one another. Two or more of the plurality of the light sources include respective light-emitting spots which emit light in the same wavelength band.