Wavelength Converting Device for Vehicle Headlights
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Solution Overview
Problem
Conventional wavelength converting devices in vehicle headlights suffer from color variation issues, leading to unfavorable light distribution patterns, and reduced light-emitting efficiency due to multipath reflections and inefficient use of light-emitting surfaces.
Innovation Solution
The development of wavelength converting devices that utilize a movable mirror to scan a laser beam, incorporating a transparent substrate with a grid-like groove and dichroic filter, and a wavelength converting layer with phosphors, allowing for efficient light emission with high color uniformity and intensity by using side surfaces of wavelength converting chips as reflectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional wavelength converting layer is used in vehicle headlights, then the device can emit light, but color variation occurs leading to unfavorable light distribution patterns
Solution Approach 1:
The wavelength converting layer is divided into multiple wavelength converting chips arranged in an array. Each chip has dimensions of 0.5mm to 2.0mm in width and 1.0mm to 4.0mm in length, creating discrete light emission regions that can be individually controlled and optimized for uniform color distribution across the entire layer.
Solution Approach 2:
Each wavelength converting chip is designed with specific local properties including controlled phosphor concentration, chip thickness, and geometric dimensions. The side surfaces of adjacent chips are positioned to substantially contact each other, creating localized reflection zones that ensure uniform color characteristics in different regions of the wavelength converting layer.
2Power
If light is emitted from a conventional wavelength converting layer, then illumination is provided, but multipath reflections occur reducing light-emitting efficiency
Solution Approach 1:
The harmful multipath reflections are extracted and eliminated by precisely controlling the optical path. The laser beam diameter is maintained smaller than the chip incident surface area, and the side surfaces of adjacent chips substantially contact each other, preventing light from undergoing multiple reflections between chip boundaries and the dichroic filter, thus removing energy loss pathways.
Solution Approach 2:
The optical configuration is designed in advance to prevent multipath reflections before they can occur. The laser beam diameter is predetermined to be smaller than the chip incident surface, and the chip arrangement is designed with side surfaces substantially contacting each other, preliminarily eliminating the conditions that would cause energy-wasting multipath reflections.
3Illumination intensity
If the laser beam diameter is increased to cover larger area, then more light is emitted, but color uniformity deteriorates
Solution Approach 1:
The wavelength converting layer is segmented into multiple chips that can be selectively activated. By controlling the laser beam to illuminate only specific chips or regions, the system can provide high light intensity from active chips while maintaining color uniformity, as each chip is designed with optimized phosphor composition and geometry for consistent color output.
Solution Approach 2:
The system enables dynamic control of light emission by selectively activating different wavelength converting chips or regions. The laser beam can be scanned across or focused on specific chips based on required illumination patterns, providing high intensity where needed while maintaining color uniformity through precise control of which chips are active at any given time.
4Area of stationary object
If adjacent wavelength converting chips are used to increase coverage, then larger area is illuminated, but light leakage occurs between chips
Solution Approach 1:
The side surfaces of adjacent wavelength converting chips are designed to substantially contact each other, merging the optical boundaries between chips. This contact configuration eliminates gaps where light leakage could occur, while the chips collectively provide expanded illumination area. The merged boundary also prevents light from escaping laterally between chips.
Solution Approach 2:
The interface regions between adjacent chips are designed with specific local properties where side surfaces substantially contact each other. This localized contact configuration at chip boundaries prevents light leakage in the critical transition zones between chips, while the overall array provides expanded illumination coverage.
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 provides desirable light distribution patterns with high light-emitting efficiency and color uniformity, suitable for various lighting applications such as stage lights, street lights, and vehicle headlights, by preventing light leakage and optimizing light emission from intended chips.
Implementation Method 1
a laser device 31 configured to emit a laser beam 31L
Implementation Method 2
a wavelength converting layer 15 having a light-emitting surface 15S disposed on the filter top surface 13T of the dichroic filter 13, and including a plurality of wavelength converting chips 17
Implementation Method 3
a dichroic filter 13 having a filter top surface 13T disposed on the substrate top surface 11T of the transparent substrate 11
Implementation Method 4
each of the side surfaces 17L of the adjacent wavelength converting chips 17 substantially separating so as to face with respect to each other between the boundary end E and the grid-like groove V of the transparent substrate 11
Data Source
Figure 1a~1b
Figure 2a~2d
Figure 3a~3d
AI summary
A wavelength converting device (10), a method for manufacturing the device and a lighting unit using the device can emit various color lights. The converting device can include a substrate (11), a filter (13) disposed on the substrate and the wavelength converting layer (15) including a plurality of wavelength converting chips (17) disposed on the filter, and can be manufactured by almost cutting process. The lighting unit using the device includes a laser device, a movable mirror and a controller, which enables the laser device to generate a pulsed laser beam and enables the movable mirror to scan the pulsed laser beam into a respective one of the wavelength converting chips. Thus, the disclosed subject matter can provide the wavelength converting device, which can form various colored light distribution patterns including a white light to use for a headlight and the like, and can provide methods for efficiently manufacturing such the devices with high accuracy.