Light-emitting device with segmented reflectors for high extraction efficiency
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Solution Overview
Problem
Existing light-emitting devices with multiple semiconductor laser elements face challenges in achieving high light extraction efficiency, as light emitted from the semiconductor laser elements can leak towards the opposite side, reducing the concentration of light in a small region and affecting output.
Innovation Solution
A light-emitting device configuration that includes multiple semiconductor laser elements and reflectors, with scattering materials and wavelength-selective reflectors arranged to reflect and concentrate light emitted from the semiconductor laser elements in a direction different from their incidence, minimizing light leakage and enhancing extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple semiconductor laser elements are mounted to obtain high output, then the light extraction efficiency decreases because light leaks toward the opposite side and cannot be concentrated in a very small region
Solution Approach 1:
The patent divides the light management system into multiple reflectors (first reflector, second reflector, third reflector) that are spatially separated and positioned at different locations. Each reflector handles light from specific semiconductor laser elements, segmenting the light path management to prevent leakage and improve concentration efficiency
Solution Approach 2:
The patent introduces a wavelength-selective reflector as an intermediary component between the semiconductor laser elements and the phosphor. This intermediary selectively reflects specific wavelengths while transmitting others, enabling precise light concentration and wavelength conversion without direct interference between components
2Loss of energy
If a semitransparent film and reflective film are used to prevent excitation light leakage, then light extraction efficiency improves, but it becomes difficult to concentrate light in a very small region when multiple semiconductor laser elements are mounted
Solution Approach 1:
The patent applies different optical properties to different spatial regions by positioning specific reflectors at different locations. The first reflector, second reflector, and third reflector are placed at distinct positions to handle light from different semiconductor laser elements, creating locally optimized light concentration zones that can be tightly focused
Solution Approach 2:
The patent transitions from a planar light management approach to a three-dimensional configuration with reflectors positioned at different heights and locations. The wavelength-selective reflector is placed between the semiconductor laser elements and phosphor at a specific vertical position, creating multi-dimensional light path control that enables both efficiency and concentration
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
The configuration achieves high light extraction efficiency by effectively concentrating light emitted from multiple semiconductor laser elements in a small region, reducing light leakage and improving output.
Implementation Method 1
a plurality of reflectors including a first reflector for reflecting light emitted from the first semiconductor laser element, each of reflectors reflecting light emitted from corresponding one of the plurality of semiconductor laser elements
Implementation Method 2
a plurality of scattering materials that are each arranged in a region between one of the plurality of semiconductor laser elements and corresponding one of the plurality of reflectors
Implementation Method 3
a wavelength-selective reflector that transmits light emitted from the predetermined semiconductor laser element and reflects light wavelength-converted by the predetermined scattering material
Implementation Method 4
a light-emitting film containing a phosphor which absorbs the excitation light transmitted through the semitransparent film and emits visible output light with a different wavelength from that of the excitation light
Data Source
AI summary
A light-emitting device includes a plurality of semiconductor laser elements including a first semiconductor laser element, and a plurality of reflectors including a first reflector for reflecting light emitted from the first semiconductor laser element, each of reflectors reflecting light emitted from corresponding one of the plurality of semiconductor laser elements. Light emitted from the first semiconductor laser element passes through a gap between two of the plurality of reflectors excluding the first reflector and reaches the first reflector. Lights emitted from the plurality of semiconductor laser elements are extracted in a direction different than an incident direction thereof toward the plurality of reflectors.