LED Housing Cavity with Absorptive Adhesive for Beam Control
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Solution Overview
Problem
Existing housings for electromagnetic radiation-emitting optoelectronic components, such as LEDs, suffer from irregular radiation characteristics and unwanted light emission outside the desired direction due to the use of optics and adhesive materials that cause light to be refracted and exit from side surfaces, posing challenges in applications like vehicle headlights where precise beam control is necessary.
Innovation Solution
A housing design featuring a reflective cavity with absorptive materials and a cover connected to the housing underpart using an absorptive adhesive, where the cover's side surfaces are coated with absorptive layers to absorb light exiting from the side surfaces, ensuring minimal to no light emission outside the preferred radiation angle, and the use of specific materials like ceramic and glass for thermal resistance and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cover is connected to the housing underpart using adhesive material, then the housing structure is sealed and protected, but light is optically coupled into the cover through the adhesive bead and emitted from side surfaces, causing unwanted radiation outside the preferred angle
Solution Approach 1:
The patent converts the harmful adhesive bead that causes light leakage into a beneficial light-absorbing element by applying black paint or absorptive material to the adhesive bead and the inner surface of the cover at the periphery. This transforms the source of unwanted radiation into a light-trapping feature that prevents lateral light emission while maintaining the sealing function.
Solution Approach 2:
The patent applies different optical properties to different regions of the cover: the central region remains transparent for light transmission, while the peripheral region (inner surface near the edge and adhesive bead) is made absorptive through black painting. This local differentiation allows the cover to simultaneously transmit desired light and absorb unwanted lateral radiation.
2Strength
If the cover side surfaces are not ground to be planar, then the cover provides protection and structural integrity, but incoupled light is refracted in all directions by the side surfaces, resulting in undesired light emission
Solution Approach 1:
The patent accepts the non-planar side surfaces that provide structural strength but converts their light-scattering effect from harmful to beneficial by applying absorptive material to these surfaces. The rough or non-planar surfaces that would normally refract light in unwanted directions now trap light through absorption, preventing lateral emission while maintaining structural integrity.
Solution Approach 2:
The patent applies absorptive properties specifically to the cover's side surfaces and peripheral regions, while maintaining the overall protective structure. This localized treatment allows the cover to provide structural strength through its intact form while preventing unwanted light emission from its surfaces.
3Manufacturing precision
If projection lenses are used to project beam cones onto a desired plane, then the radiation angle is controlled, but irregularities in the LED radiation characteristic are amplified and become troublesome
Solution Approach 1:
The patent removes the projection lens from the optical system and replaces it with a housing-based light control solution. By using the housing cavity shape, reflector surfaces, and absorptive materials directly in the housing structure, the patent eliminates the lens that was amplifying LED irregularities, while still achieving the desired beam angle control through geometric light management.
4Manufacturing precision
If special devices are used to attenuate light intensity outside the preferred radiation angle, then the radiation characteristic is improved, but the device complexity increases
Solution Approach 1:
The patent merges the light control function with the housing structure itself. Instead of adding separate attenuation devices, the housing cavity shape, reflector surfaces, absorptive coatings on the cover and adhesive bead, and geometric features are integrated into the housing design, achieving radiation angle control without increasing overall device complexity.
Solution Approach 2:
The housing structure performs multiple functions: it provides mechanical protection, thermal management, and optical control. The cover serves both as a protective element and a light management component through its absorptive peripheral regions. The adhesive bead serves both as a bonding agent and a light-trapping feature, eliminating the need for separate attenuation devices.
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 effectively reduces unwanted light emission by absorbing or deflecting light into the desired radiation direction, enhancing the radiation characteristic and preventing interference from scattered light, thus improving the performance of LEDs in floodlight and projection applications.
Implementation Method 1
The absorptive adhesive connects the cover to the housing underpart in such a way that electromagnetic radiation exiting from the side surfaces of the cover is absorbed
Implementation Method 2
The inner walls of the cavity can be shaped in the manner of a reflector, such that a portion of the electromagnetic radiation emitted by the semiconductor chip is deflected into a desired radiation solid angle by these reflective inner walls
Implementation Method 3
Light is optically coupled into the cover through this bead and leaves it only upon reaching the side surfaces of the cover. The cover functions as a sort of a light guide.
Data Source
AI summary
A housing includes a housing underpart, the housing underpart being provided with a housing cavity. The housing cavity comprises an opening on one housing side and, on the floor of the cavity, contains an electromagnetic radiation emitting semiconductor chip. A cover that is at least partially transparent to the electromagnetic radiation covers the housing cavity. A method for emitting electromagnetic radiation in a preferred direction is also disclosed.