LED Chip Manufacturing with Transparent Connector Reflector
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Solution Overview
Problem
Existing methods for manufacturing light emitting diodes (LEDs) face challenges in achieving high light coupling-out efficiency, particularly when using sapphire flip chips, as they often result in radiation absorption near solder contacts and require precise positioning, which is difficult to achieve with heated bond heads when fluorescent bodies are already attached.
Innovation Solution
A method involving the sequential steps of providing a light emitting diode chip with a semiconductor layer sequence, soldering it to a carrier, applying a transparent connecting means to the chip side faces, attaching a fluorescent body, and creating a reflector on the outer faces of the connecting means to direct radiation away from the carrier, allowing for efficient light extraction and improved thermal contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heated bond heads are used for positioning and soldering LED chips, then thermal contact is improved, but precise positioning becomes difficult when fluorescent bodies are already attached
Solution Approach 1:
The patent applies connecting means to the substrate before attaching the fluorescent body, creating a prepared state that allows subsequent precise positioning and soldering operations without disturbing the fluorescent body. This preliminary preparation enables thermal contact establishment while preserving positioning precision.
2Strength
If soldering is performed on LED chips with attached fluorescent bodies, then electrical and mechanical connection is achieved, but the adhesive and fluorescent body may be damaged
Solution Approach 1:
The connecting means is applied and allowed to set before the fluorescent body is attached and before soldering occurs. This preliminary application creates a stable foundation that protects the fluorescent body from damage during subsequent high-temperature soldering operations, while still enabling strong electrical and mechanical connections.
Solution Approach 2:
The connecting means serves as a protective layer or cushion between the soldering process and the fluorescent body, absorbing or mitigating the thermal and mechanical stress that would otherwise damage the adhesive and fluorescent body during soldering.
3Strength
If light emitting diode chips are attached to carriers, then electrical and mechanical contact is established, but light coupling-out efficiency decreases due to radiation absorption near solder contacts
Solution Approach 1:
The connecting means acts as an intermediary substance between the substrate and fluorescent body that is transparent to the generated radiation. This intermediary material allows strong electrical and mechanical contact while preventing radiation absorption, thereby maintaining high light coupling-out 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 method enhances light extraction efficiency by enabling precise positioning and thermal contact, allowing for the use of sapphire flip chips with thin solder contact surfaces and improving color rendering quality, while preventing damage to the adhesive and fluorescent body during the soldering process.
Implementation Method 1
The at least one phosphor is designed to absorb at least part of the radiation generated in the light emitting diode chips and to convert it into radiation, in particular visible light, of a longer wavelength
Implementation Method 2
creating a reflector on the outer faces of the connecting means to direct radiation away from the carrier
Implementation Method 3
soldering chip contact surfaces to carrier contact surfaces
Data Source
AI summary
A method for manufacturing light emitting diodes and a light emitting diode are disclosed. In an embodiment a method includes providing a light emitting diode chip with a growth substrate and with a semiconductor layer sequence for generating radiation, soldering chip contact surfaces located on a chip underside of the semiconductor layer sequence facing away from the growth substrate to carrier contact surfaces of a carrier, applying a liquid connector transparent to the radiation to a substrate upper side of the growth substrate facing away from the semiconductor layer sequence, fastening a fluorescent body to the substrate upper side, the connector being partially displaced by the fluorescent body from the substrate upper side so that chip side faces are predominantly covered by the connector and generating a reflector on outer faces of the connector facing away from the light emitting diode chip on the chip side faces, the outer faces pointing in a direction away from the carrier.