Light Guide Free-Form Surface for Uniform LED Illumination
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Solution Overview
Problem
Conventional semiconductor light-source apparatuses face challenges in achieving high light utilization efficiency and uniform lighting, particularly in projector and in-vehicle head-up display applications, where high light quantity and uniformity are required.
Innovation Solution
A light source apparatus comprising a plurality of semiconductor light source elements, collimators, and a light guide with a free-form surface shape to control light distribution, enhancing light utilization efficiency and uniformity by guiding and condensing light effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional lenses are used to condense light from semiconductor light-emitting elements, then the apparatus structure is simple and cooling is efficient, but light utilization efficiency and uniform lighting characteristics are insufficient
Solution Approach 1:
The optical system is segmented into multiple functional components: collimator lenses for each light-emitting element, a light guide with incidence and emission portions, and free-form surfaces for light distribution control. This segmentation allows each component to optimize specific aspects of light management, improving overall light utilization efficiency while maintaining manageable system complexity
Solution Approach 2:
A light guide is introduced as an intermediary component between the collimator lenses and the final light output. The light guide with free-form surfaces acts as a mediator that redistributes light uniformly, converting the concentrated light from individual elements into uniform planar lighting, thereby significantly improving light utilization efficiency
2Illumination intensity
If conventional lighting structures are used, then the apparatus may be simpler to manufacture, but the light quantity and uniformity required for projector and HUD applications are not achieved
Solution Approach 1:
Multiple light-emitting elements and their corresponding collimators are merged into a unified lighting system with a common light guide. This merging approach consolidates light from multiple sources into a single uniform output, achieving high light quantity and uniformity suitable for projector and HUD applications while managing the quantity of components through systematic integration
3Loss of energy
If more optical components are added to improve light condensation, then light utilization efficiency improves, but the apparatus size and weight increase
Solution Approach 1:
The light guide is implemented as a thin planar structure with free-form surfaces, functioning as a lightweight optical element that can be integrated into compact apparatus designs. This thin-film approach maintains high light utilization efficiency through effective light redistribution while minimizing the addition of weight and volume to the overall system
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 results in a compact, lightweight light source apparatus with improved light utilization efficiency and uniform lighting, suitable for high-light-quantity applications like projectors and in-vehicle head-up displays.
Implementation Method 1
emitted light from the element has been condensed by utilizing one or plural lenses provided opposite the element
Implementation Method 2
the light guide has a free-form surface shape for realizing predetermined light distribution control on at least one of the incidence surface and the emission surface
Data Source
AI summary
Provided is a light source apparatus that is small and lightweight, has high light utilization efficiency, and is easily utilizable as a modularized, planar light source. The light source apparatus 10 has a light source unit including a plurality of LED elements 14, a LED collimator 15 including a plurality of collimator elements each arranged on a light-emitting axis of each of the plural LED elements 14, and a light guide 17 disposed on an emission side of the LED collimator 15. The light guide 17 includes an incidence portion 171 having an incidence surface on which light on the light-emitting axis from the LED elements 14 is incident, and an emission portion 173c having an emission surface emitting light, and has a free-form surface shape for realizing predetermined light distribution control on at least one of the incidence surface and the emission surface.