Light Source Unit Laser Multiplexing Phosphor Protection
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Solution Overview
Problem
The challenge is to create a light source unit that can suppress phosphor deterioration while achieving high luminance, particularly when using semiconductor laser elements with diverging light, which can cause crosstalk and reduce wavelength conversion efficiency due to the need for closer spacing and higher intensity excitation light, leading to potential phosphor damage.
Innovation Solution
A light source unit comprising semiconductor laser elements, a phosphor substrate, and an optical system with a first lens system that condenses laser light without parallelization, a multiplexing optical member for uniform intensity distribution, and a second lens system that directs the light onto the phosphor, allowing for efficient wavelength conversion without damaging the phosphor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If semiconductor laser elements are arranged at narrow intervals to achieve high luminance, then light intensity increases, but crosstalk occurs due to diverging light spreading
Solution Approach 1:
A light separating plate is introduced as an intermediary component between adjacent semiconductor laser elements. This plate selectively transmits light from each laser element while blocking diverging light from adjacent elements, thereby preventing crosstalk while maintaining high light intensity output
2Illumination intensity
If excitation light intensity is increased to achieve higher luminance, then light output increases, but phosphor deterioration accelerates
Solution Approach 1:
The light separating plate acts as a mediator that enables efficient light extraction from each laser element without requiring excessive excitation intensity. By preventing crosstalk and improving light extraction efficiency, the system achieves high luminance with reduced phosphor stress, extending phosphor lifespan
3Reliability
If multiple optical components are added to prevent crosstalk, then crosstalk is reduced, but device complexity increases
Solution Approach 1:
The light separating plate performs multiple functions simultaneously: it separates light from adjacent laser elements, extracts light efficiently from each element, and contributes to overall optical path management. This multi-functionality reduces the need for additional dedicated components, maintaining system compactness
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 high-intensity light emission with reduced phosphor deterioration, maintaining wavelength conversion efficiency and preventing phosphor damage, while also minimizing the size and component count of the optical engine.
Implementation Method 1
a first lens system that receives laser light beams emitted from the respective semiconductor laser elements directly without substantial parallelization of the respective received laser light beams, and that condenses the received laser light beams on the light entering surface
Implementation Method 2
a multiplexing optical member that multiplexes laser light beams condensed by the first lens system, into a multiplexed laser light beam having a spatially-uniform intensity distribution
Implementation Method 3
a second lens system that allows the multiplexed laser light beam that has exited from the light exiting surface to be condensed onto the one or more kinds of phosphor
Implementation Method 4
one or more kinds of phosphor... The phosphor wheel includes a wheel substrate serving as a circular substrate formed with three regions that are adjacent to one another in a circumferential direction and each having a fan-like shape. The wheel substrate includes: a region in which a phosphor that absorbs blue light and emits green light is arranged
Data Source
AI summary
Provided is a light source unit that includes: one or more kinds of phosphor; a substrate, on which the one or more kinds of phosphor is applied; a plurality of semiconductor laser elements arrayed at a predetermined interval in a package, wherein each of the semiconductor laser elements emits a laser light beam through a light emission region; and a first optical system that comprises a first lens system, a multiplexing optical member having a light entering surface and a light exiting surface, and a second lens system, wherein the first optical system directs the laser light beams emitted from the respective semiconductor laser elements toward the substrate, the first lens system receives the laser light beams emitted from the respective semiconductor laser elements directly without substantial parallelization of the respective received laser light beams, and condenses the received laser light beams on the light entering surface of the multiplexing optical member, the multiplexing optical member multiplexes the laser light beams condensed by the first lens system, into a multiplexed laser light beam having a spatially-uniform intensity distribution, and the second lens system condenses the multiplexed laser light beam that has exited from the light exiting surface of the multiplexing optical member onto the one or more kinds of phosphor.