Vehicle Instrument Panel LED Backlighting with Elliptical Reflector
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Solution Overview
Problem
Existing vehicle instrument panel LED backlighting systems suffer from non-uniform lighting due to the spatial emission curve of LEDs, leading to brighter spots and reduced light intensity at angles, and existing solutions either require additional components or decrease light efficiency.
Innovation Solution
A vehicle instrument panel with a LED backlighting device featuring a reflector with a parabolic and elliptical arc-shaped surfaces that redirects light from the LEDs to ensure uniform illumination across the graphic area, eliminating the need for light-guide elements and special treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If LEDs are arranged directly beneath the transparent portion to illuminate it, then the structure is simple and space-saving, but the lighting uniformity deteriorates due to Lambert's Law causing brighter spots and reduced light intensity at angles
Solution Approach 1:
A reflector is introduced as an intermediary component between the LED and the transparent portion. The reflector has a specific geometry with an elliptical arc-shaped reflecting surface that redirects light rays from the LED to achieve uniform illumination across the graphic area, eliminating the need for light-guide elements or special treatments on the transparent portion.
2Illumination intensity
If a light-guide element is added to convey light from LEDs to the transparent portion, then lighting uniformity is improved, but device complexity and manufacturing cost increase due to additional components
Solution Approach 1:
The patent extracts and eliminates the light-guide element from the backlighting system. Instead of using a separate light-guide component to convey and diffuse light, the invention integrates the light redirection function directly into the reflector geometry, which has an elliptical arc-shaped reflecting surface that inherently provides uniform light distribution.
3Illumination intensity
If silk-screen printing treatment is applied to the transparent portion, then lighting uniformity is improved, but light efficiency deteriorates due to light attenuation
Solution Approach 1:
The reflector serves as an intermediary that redirects light before it reaches the transparent portion, achieving uniform illumination without requiring any attenuating treatment on the transparent portion itself. This preserves the light transmission efficiency while still providing uniform lighting across the graphic area.
4Illumination intensity
If a reflector with complex geometry is used to achieve uniform lighting, then lighting uniformity is improved, but manufacturing complexity increases
Solution Approach 1:
The reflector employs an elliptical arc-shaped reflecting surface, which is a curved geometry that can be manufactured using standard molding techniques. This curved surface is optimized to redirect light rays from the LED to achieve uniform illumination across the graphic area while remaining manufacturable with conventional processes.
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
Achieves uniform lighting with at least 80% efficiency without additional components or light attenuation, maintaining the overall light power and reducing manufacturing complexity.
Implementation Method 1
A reflector reflects the light of the LED source toward an outlet engaged by the light permeable portion. The reflector includes a first reflecting surface, which defines a first cavity and is aligned with the outlet along an illumination axis spaced apart from the optical axis.
Implementation Method 2
a second reflecting surface, which is aligned with the LED source along the optical axis, and defines a second cavity communicating with the first cavity through an aperture and which reflects most of the incident light toward the aperture.
Data Source
AI summary
In an instrument panel, a LED backlighting device has at least one LED source, the optical axis of which corresponds to the direction in which the intensity of the emitted light is maximum. The light of the LED source is reflected onto a graphic area by a first and a second reflecting surface. The first surface defines a first cavity and is aligned with the graphic area along an illumination axis spaced apart from the optical axis, while the second surface is aligned with the LED source along the optical axis and defines a second cavity communicating with the first cavity through an aperture. The second surface is a cylindrical surface, defined by an elliptical generatrix and configured so as to block the light rays that would be directed from the LED source onto the graphic area.