LED Package Lens with Blocking Structure for Dispensing Molding
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Solution Overview
Problem
Conventional LED packages with lenses formed by injection molding or dispensing molding suffer from high production costs and low light output efficiency due to total reflection of light beyond the critical angle, respectively.
Innovation Solution
An LED package with a blocking structure made of ceramic or metal materials surrounding the LED chip, where the encapsulation body is formed by dispensing molding with a hemispherical light output surface, reducing the incident angle and minimizing total reflection by connecting directly with the blocking structure's resisting surface vertically, thereby enhancing light output efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the lens is formed by injection molding, then the lens quality and light output efficiency are improved, but the production cost increases
Solution Approach 1:
The patent replaces expensive injection molding with a cheaper dispensing molding process. The lens is formed by dispensing curable material directly onto the substrate and curing it, eliminating the need for expensive injection molding equipment and tools while achieving sufficient lens quality for the application
Solution Approach 2:
The patent modifies the lens formation process by changing from injection molding to dispensing molding, and adjusts the lens curvature radius to be smaller than conventional designs. This parameter change ensures that the angle of incidence remains below the critical angle, preventing total internal reflection while using the cheaper dispensing process
2Ease of manufacture
If the lens is formed by dispensing molding, then the production cost is reduced, but the light output efficiency decreases due to total reflection
Solution Approach 1:
The patent changes the lens curvature radius parameter to be smaller than conventional dispensing molded lenses. This ensures that light rays strike the lens surface at angles below the critical angle, preventing total internal reflection and maintaining high light output efficiency while still using the cost-effective dispensing molding process
Solution Approach 2:
The patent applies a smaller amount of curable material during dispensing to form a lens with controlled, smaller curvature. This partial action (using less material and smaller dispensing volume) creates the optimal lens shape that prevents total reflection while maintaining the simplicity and low cost of the dispensing process
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 increases light output efficiency by reducing the angle of incidence below the critical angle, eliminating the need for additional shaping adjustments and reducing production costs compared to conventional methods.
Implementation Method 1
the encapsulation body is formed by dispensing molding with a hemispherical light output surface, reducing the incident angle and minimizing total reflection
Implementation Method 2
the lens formed by the dispensing molding has a large radius of curvature whereby an angle of incidence of light generated by the LED die to a light output surface of the lens is more likely to be equal to or larger than a critical angle of the lens. In this state, more light is prone to be totally reflected by the lens
Data Source
AI summary
A light emitting diode (LED) package includes a substrate with a flat top surface, an LED chip mounted on the substrate, and a group of blocking structure and encapsulation body. The LED chip electrically connects with the substrate. The blocking structure surrounds the LED chip. The encapsulation body covers the LED chip. A bottom of the encapsulation body is enclosed by the blocking structure; the encapsulation body has a light outputting surface, and an outer surface of the blocking structure is continuously connected with the light outputting surface. The light outputting surface has a semispherical profile. An angle between a normal line extending from the outer surface of the blocking structure and perpendicular to the substrate and a tangent line tangent to the light outputting surface at a point thereof adjacent to the outer surface is smaller than 60 degrees.