VCSEL Resin Diffuser Structure for Wider Directivity Angle
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Solution Overview
Problem
Semiconductor light emitting devices, particularly those using VCSEL elements, face challenges in achieving the same level of directivity as LEDs due to the directional emission of light, which limits their application and efficiency.
Innovation Solution
Incorporating a light-transmissive resin member with a diffusing agent, such as silica, into the semiconductor light emitting device to scatter light and increase the directivity angle, while maintaining radiation intensity and optical output by adjusting the mixture ratio of the diffusing agent within the resin member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a semiconductor laser element is used as a light source, then higher output and lower power consumption are achieved, but the directivity angle is reduced compared to LEDs
Solution Approach 1:
A light-transmissive resin member is introduced as an intermediary between the semiconductor laser element and the external environment. This resin member contains a diffusing agent that scatters the light, increasing the directivity angle while preserving the high output characteristics of the laser element. The resin member acts as a mediator that transforms the directional laser beam into a more diffuse light distribution.
Solution Approach 2:
The directivity angle is adjusted by changing the concentration of the diffusing agent in the resin member. By controlling the mixture ratio of the diffusing agent (greater than 0% and less than or equal to 60%), the light scattering properties are optimized to achieve the desired directivity angle while maintaining high optical output.
2Shape
If the directivity angle is increased using a diffusing agent, then light scattering is improved, but thermal stress may increase causing potential breakage
Solution Approach 1:
The resin member is specifically selected to have a thermal expansion coefficient that matches or is close to that of the semiconductor laser element. This thermal expansion matching reduces differential thermal stress during temperature changes, preventing breakage while allowing the use of diffusing agents to increase the directivity angle.
Solution Approach 2:
The light-transmissive resin member is formulated as a composite material containing both the resin base and the diffusing agent in a controlled mixture ratio. This composite structure provides both the light scattering function (increasing directivity angle) and thermal compatibility (reducing thermal stress) simultaneously.
3Shape
If the mixture ratio of diffusing agent is increased to maximize directivity angle, then light scattering is improved, but optical output and radiation intensity decrease
Solution Approach 1:
The concentration of the diffusing agent is precisely controlled within the range of greater than 0% and less than or equal to 60% of the resin member. This optimized parameter range achieves the maximum directivity angle improvement while minimizing the loss of optical output and radiation intensity, balancing scattering effectiveness with light transmission.
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 solution enhances the directivity angle of the semiconductor light emitting device, allowing it to achieve performance comparable to LEDs with higher output and lower power consumption, and reduces thermal stress, thereby preventing potential breakage from thermal expansion.
Implementation Method 1
a diffusing agent (82) mixed into the resin member (80). The diffusing agent (82) reflects light from the semiconductor laser element (20) to a position that differs from a peak position of optical output of the semiconductor laser element (20)
Data Source
AI summary
A semiconductor light emitting device includes a semiconductor laser element including a light emitting surface from which a laser beam is emitted and a light-transmissive resin member covering the light emitting surface of the semiconductor laser element. The semiconductor light emitting device further includes a diffusing agent mixed into the resin member.