Dichromatic Light Pipe for Laser Illumination Tolerance
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Solution Overview
Problem
Laser diode illuminating devices face issues with reduced light efficiency due to manufacturing tolerances and assembly decentering, causing light spots to expand and deviate from desired locations, which affects the illumination distance and service lifetime.
Innovation Solution
The introduction of a dichromatic light pipe with a tapered design and a dichromic coating that reflects specific wavelengths, allowing for increased tolerance in collimating lens alignment and improved light transmission, combined with an elliptical reflector for focused beam convergence, enhances light efficiency and miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If collimating lenses are used to collimate laser beams, then light directionality is improved, but manufacturing tolerance and assembly decentering cause light spots to expand and deviate, reducing light efficiency
Solution Approach 1:
The patent introduces a light pipe as an intermediary component between the collimating lens and the reflector. The light pipe receives the deviated light spot and guides it to the reflector through its internal reflective walls, acting as a mediator that compensates for the positional deviation caused by manufacturing tolerances and assembly errors.
Solution Approach 2:
The light pipe changes the spatial parameters of the light path by providing an extended guidance path with reflective internal walls. This allows the light to travel a longer distance and be redirected to the correct position on the reflector, compensating for initial deviations.
2Ease of operation
If a normal light pipe reflecting all wavelengths is used, then light guidance is achieved, but yellow light is reflected and scattered causing the illuminating device to fail to operate
Solution Approach 1:
The light pipe's circumferential wall is designed with non-uniform optical properties - it reflects blue light (first wavelength) while transmitting yellow light (second wavelength). This local quality differentiation allows the light pipe to guide blue light to the exciter while allowing converted yellow light to pass through to the reflector.
Solution Approach 2:
The patent utilizes the color/wavelength-dependent optical properties of the light pipe material. The circumferential wall is configured to have different reflectivity and transmissivity for different wavelengths, reflecting blue light while transmitting yellow light, thereby enabling the light pipe to differentiate between the excitation light and the converted light.
3Loss of energy
If tolerance in manufacturing and assembly is reduced to improve light spot accuracy, then light efficiency is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The light pipe serves as a tolerance-compensating intermediary that relaxes the precision requirements for collimating lens alignment. By providing an extended light path with reflective walls, it guides light from deviated positions to the correct reflector location, thereby maintaining light efficiency without requiring ultra-precise manufacturing and assembly.
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 efficiency by allowing for increased allowable deviation in collimating lenses, providing desirable wavelength light, and prolonging the service lifetime of the exciter while maintaining compactness and uniform luminance distribution.
Implementation Method 1
the exciter converts the light having the first wavelength into light having the second wavelength
Implementation Method 2
circumferential wall of the light pipe is configured to reflect the light having the first wavelength and to transmit the light having the second wavelength
Data Source
AI summary
An illuminating device may include a light source, an optical unit configured to adjust direction of light from the light source, a reflector, a light pipe, and an exciter. The light pipe may receive light having a first wavelength from the optical unit and direct the light having the first wavelength onto the exciter. The exciter may convert the light having the first wavelength into light having the second wavelength and reflects the light having the second wavelength to the reflector. A circumferential wall of the light pipe is configured to reflect the light having the first wavelength and to transmit the light having the second wavelength.