Planar Laser Light Source Unit for Compact Projector Optical Layout
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Solution Overview
Problem
Conventional projectors with high-intensity discharge lamps face challenges in size reduction and cost optimization due to complex optical layouts required for aligning red, green, and blue light sources, which also limit power efficiency and design flexibility.
Innovation Solution
A light source unit featuring two types of laser emitting elements arranged in a planar fashion, with a diffusing unit and a light source control unit for time-sharing illumination, simplifying the optical layout and allowing for a compact projector design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional high-intensity discharge lamps are used with separate red, green, and blue light sources, then color reproduction is achieved, but the optical layout becomes complex and device size increases
Solution Approach 1:
The patent merges multiple light sources (blue LED and violet laser) into a single integrated light source unit. The blue LED and violet laser are arranged in a planar fashion with their optical axes aligned, allowing them to function as a unified illumination system. This combining approach eliminates the need for separate optical paths for different color sources, thereby simplifying the overall optical layout while maintaining color reproduction capability.
Solution Approach 2:
The light source unit is designed to serve multiple functions simultaneously. The blue LED provides both direct blue light and serves as a pump source for the violet laser. The aligned arrangement of blue LED and violet laser allows the system to generate multiple wavelength components (blue, violet, and green via phosphor conversion) from a single integrated unit, enabling multi-functional operation with simplified optics.
2Illumination intensity
If multiple separate light emitting diodes are used to increase red light quantity, then light output is improved, but device size and production cost increase
Solution Approach 1:
The patent introduces a green phosphor layer as an intermediary medium that converts violet laser light into green light. This phosphor-mediated conversion approach allows generation of green light without requiring separate green LED sources. The violet laser serves as an excitation source for the phosphor, which then emits green light, thereby achieving color generation through optical conversion rather than requiring multiple discrete light sources.
3Manufacturing precision
If complex optical systems with multiple lenses and mirrors are used to align light sources, then optical axis alignment is achieved, but production cost increases
Solution Approach 1:
The blue LED and violet laser are arranged in a planar configuration with their optical axes naturally aligned in the same plane. This planar arrangement eliminates the need for complex three-dimensional optical alignment systems involving multiple lenses and mirrors. The inherent geometric relationship in the planar layout provides natural optical axis alignment, significantly simplifying the optical system and reducing manufacturing complexity and costs.
Solution Approach 2:
Instead of using complex optical elements (lenses and mirrors) to achieve alignment, the patent inverts the approach by designing the light source arrangement itself to provide natural alignment. The planar fashion arrangement of blue LED and violet laser with coincident optical axes creates intrinsic alignment without requiring additional alignment optics, thereby simplifying the system from the source level rather than adding complexity at the optical element level.
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 enables a smaller, more energy-efficient projector with improved color reproducibility and reduced production costs by aligning the optical axes of red, green, and blue light sources efficiently, enhancing the projector's design flexibility and power consumption.
Implementation Method 1
a diffusing unit disposed on an optical path of light emitted from the laser light source unit to diffuse light emitted from the laser light source unit
Implementation Method 2
a green luminescent material layer which emits light of green wavelength band by receiving light of blue wavelength band as excitation light
Data Source
AI summary
A projector is provided which includes a light source unit which can reduce the numbers of lenses and mirrors and which can control quantity of light of each color.A light source unit of the invention includes a laser light source unit 70 which has a plurality of red laser elements 71R and a plurality of blue laser elements 71B as two types of laser emitting elements 71 which emit light of wavelength bands which are different from each other and in which the pluralities of red and blue laser emitting elements 71R, 71B are arranged in a planar fashion, a diffusing unit which is disposed on an optical path of light emitted from the laser light source unit 70 to diffuse the light emitted from the laser light source unit 70, and a light source control unit for controlling the illumination of the laser emitting elements 71R, 71B.