Optical Element Total Internal Reflection LED Luminance
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Solution Overview
Problem
Existing optical elements for LED light sources often produce high luminance in central areas, making the light output uncomfortable for viewers due to concentrated light beams, and require additional processing steps for mirrored surfaces to address this issue.
Innovation Solution
An optical element with a front surface area designed for total reflection of light rays, including a depression to direct high-intensity light beams laterally, reducing maximum luminance and achieving uniform light distribution without mirrored surfaces, utilizing a stepped deflecting surface and recess with convex or flat walls to accommodate LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a lens arrangement with a recess and truncated cone shape is used to focus light from an LED, then light can be effectively directed and focused, but high luminance occurs in the central area making the light output uncomfortable for viewers
Solution Approach 1:
The optical element is divided into multiple functional surface areas: a light entry area, a deflecting surface area, and a front surface area. This segmentation allows different regions to perform different functions - the light entry area captures light, the deflecting surface area redirects high-intensity central beams, and the front surface area distributes light uniformly, thereby reducing central luminance while maintaining focusing capability
Solution Approach 2:
The deflecting surface area is designed with a stepped or multi-level structure that redirects light beams in different spatial directions. By introducing vertical and lateral deflection surfaces, the patent distributes concentrated central light beams across multiple dimensional paths, spreading high-intensity light over a larger area and reducing peak luminance
2Illumination intensity
If mirrored surfaces are added to lens systems to reduce central luminance, then light distribution can be improved, but additional processing steps are required increasing manufacturing complexity
Solution Approach 1:
The optical element utilizes the inherent total internal reflection property of the optical material itself to redirect light beams. The deflecting surface area is shaped to exploit the critical angle for total internal reflection, eliminating the need for separate mirrored coatings or reflective layers. This self-service approach maintains manufacturing simplicity while achieving the desired light redistribution
Solution Approach 2:
The patent changes the geometric parameters of the optical element's surfaces, specifically designing the deflecting surface area with specific angles and step heights that optimize total internal reflection. By carefully controlling these geometric parameters during molding, the patent achieves effective light redirection without requiring additional reflective coatings or complex post-processing steps
3Use of energy by moving object
If light beams are concentrated in central areas for high luminance output, then light efficiency is improved, but the maximum luminance becomes too high causing viewer discomfort
Solution Approach 1:
The optical element applies different surface characteristics to different regions: the light entry area has properties optimized for light capture, the deflecting surface area has specific angular characteristics for redirecting high-intensity beams, and the front surface area has geometry optimized for uniform light distribution. This local differentiation allows efficient light collection while distributing peak luminance across multiple areas
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 optical element effectively distributes high-intensity light beams over a larger area, reducing peak luminance and enhancing comfort for observers while maintaining high photometric effectiveness and simplicity in production.
Implementation Method 1
The front surface area is designed in such a way that second light rays of the light, which enter the optical element via the light entry area and then impinge directly on the front surface area, experience total reflection there
Implementation Method 2
first light rays of the light that enter the optical element via the light entry area are totally reflected at the deflecting surface area and then exit the optical element via the front surface area
Data Source
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AI summary
The invention relates to an optical element for influencing light emitted by a light source (1), which has a front (2) facing away from the light source (1) and a rear (3) facing the light source (1). A recess (4) for the entry of light and a deflecting surface (5) are formed on the rear (3), and a front surface (6) is formed on the front (2). The design is such that the first light rays (L1) entering the optical element via the recess (4) are totally reflected at the deflecting surface (5) and subsequently exit the optical element via the front surface (6).The front surface area (6) is shaped such that second light rays (L2) entering the optical element via the recess (4) and then striking the front surface area (6) undergo total internal reflection. This shape of the front surface area (6) allows light rays from the light source (1), which have a comparatively high intensity, to be distributed over a larger area, thus reducing the overall maximum luminance of the light emitted via the front surface area (6).