LED Device with Sheet Phosphor and Reflective Resin
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Solution Overview
Problem
Existing methods for producing white light emitting diode devices result in non-uniform phosphor layers, increased production costs, reduced luminous efficiency due to heat dissipation issues, and decreased light extraction efficiency due to absorption by the encapsulating layer and wire bonding shadows.
Innovation Solution
A method involving a phosphor layer formed in a sheet state, a light semiconductor layer, and an encapsulating resin layer with a light reflecting component, where the phosphor layer is prepared in advance to ensure uniformity, the encapsulating resin layer covers the semiconductor layer to enhance light reflection, and the device is flip-chip mounted to improve brightness and light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If spontaneous precipitation method is used to form phosphor layer, then phosphor layer can be formed, but thickness becomes non-uniform and production time increases
Solution Approach 1:
The phosphor layer is formed in advance on a release substrate before mounting the LED element, allowing uniform thickness control through screen printing or similar deposition methods. This preliminary formation eliminates the need for spontaneous precipitation during final assembly, ensuring uniformity while reducing production time.
Solution Approach 2:
The phosphor layer formation process is separated into independent steps: first forming the phosphor layer on a release substrate, then mounting the LED element, and finally releasing the phosphor layer. This segmentation allows each step to be optimized independently, ensuring uniform thickness while streamlining production.
2Ease of manufacture
If semiconductor light emitting element is spaced apart from reflecting frame portion, then wire bonding can be performed, but light extraction efficiency decreases
Solution Approach 1:
An encapsulating resin layer with light-reflecting properties is introduced as an intermediary between the semiconductor light emitting element and the reflecting frame portion. This resin layer reflects light that would otherwise be absorbed, maintaining high light extraction efficiency while allowing the element to be positioned for wire bonding.
3Reliability
If encapsulating portion contains epoxy resin at high concentrations, then encapsulation is achieved, but heat dissipation becomes insufficient
Solution Approach 1:
The encapsulating resin layer is formulated as a composite material containing epoxy resin combined with light-reflecting particles and potentially thermally conductive fillers. This composite structure provides both encapsulation protection and improved heat dissipation, while the light-reflecting properties enhance light extraction efficiency.
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
This approach results in uniform white light emission, reduced production costs, improved luminous efficiency through effective heat dissipation, and enhanced light extraction efficiency by minimizing absorption and maximizing reflection.
Implementation Method 1
a phosphor layer that can convert the blue light into yellow light
Implementation Method 2
The blue light emitted from the semiconductor light emitting element toward the side is reflected at the reflecting frame portion
Implementation Method 3
an encapsulating resin layer with a light reflecting component
Data Source
AI summary
A method for producing a light emitting diode device includes the steps of preparing a phosphor layer formed in a sheet state; forming a light semiconductor layer on one surface in a thickness direction of the phosphor layer; forming an electrode portion on one surface of the light semiconductor layer; forming an encapsulating resin layer containing a light reflecting component so as to cover the light semiconductor layer and the electrode portion; producing the light emitting diode element by partially removing the encapsulating resin layer so as to expose one surface of the electrode portion; and allowing the electrode portion to be electrically connected to the terminal, so that the light emitting diode element is flip-chip mounted on the base board.