Laser-Excited Fluorescent Light Source With Prism Redirector
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Solution Overview
Problem
Existing light emitting devices face issues with low light extraction efficiency due to laser light absorption and scattering within the fluorescent member, and challenges in heat dissipation and device miniaturization, particularly when the laser element is mounted on an inclined surface.
Innovation Solution
A light emitting device design where the laser element is positioned above the base member, with a prism-like optical member redirecting laser light diagonally onto the fluorescent member's surface, enhancing light extraction efficiency and allowing for a compact, efficient heat dissipation by shortening the distance between the laser element and the heat sink.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If laser light enters the fluorescent member from the lateral surface, then the light path is simplified, but the light extraction efficiency deteriorates due to absorption and scattering inside the fluorescent member
Solution Approach 1:
The patent changes the light entry dimension from lateral surface to upper surface of the fluorescent member. By using a lens to focus laser light vertically onto the upper surface, the light travels a shorter distance through the fluorescent material, reducing absorption and scattering losses while maintaining effective light generation.
2Loss of energy
If the laser element is mounted on an inclined surface positioned higher than the fluorescent member upper surface, then light extraction efficiency improves, but the distance between laser element and heat sink increases reducing heat release efficiency
Solution Approach 1:
The patent introduces a lens as an intermediary component between the laser element and the fluorescent member. The lens focuses the laser light onto the fluorescent member's upper surface, enabling efficient light extraction without requiring the laser element to be positioned at an elevated inclined surface, thus maintaining close proximity to the heat sink for effective heat dissipation.
3Loss of energy
If the laser element is mounted on an inclined surface, then light extraction efficiency improves, but the device size increases and mounting precision deteriorates
Solution Approach 1:
The lens serves as a mediator that decouples the mounting surface orientation from the light focusing function. The laser element can be mounted on a flat, easily manufactured surface, and the lens performs the precise light focusing onto the fluorescent member, eliminating the need for complex inclined surface machining and improving both manufacturing ease and alignment precision.
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 improves light extraction efficiency, increases luminance, and enables miniaturization of the device while ensuring effective heat release, addressing the limitations of previous designs.
Implementation Method 1
a first optical member 3 configured to change the traveling direction of laser light emitted by the laser element 2
Implementation Method 2
laser light emitted by the laser element 2 is reflected by a first optical member 3
Implementation Method 3
a fluorescent member 4, which includes a first main surface and a second main surface provided on opposite sides of the fluorescent member 4, having its second main surface fixed to the mounting surface of the base member 1
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A light emitting device includes: a base member (1); a laser element (2) disposed on or above a mounting surface of the base member; a fluorescent member (4) including a first main surface and a second main surface respectively positioned on opposite sides of the fluorescent member, the second main surface being fixed to the mounting surface of the base member; a first optical member (3) configured to change a traveling direction of laser light emitted by the laser element to be directed toward the first main surface of the fluorescent member; and a lid (5) connected to the base member and enclosing the laser element, the fluorescent member, and the first optical member in a space beneath the lid, the lid being configured to transmit light from the fluorescent member.