Recessed Light Emitting Unit for Lateral Emission
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Solution Overview
Problem
Conventional lateral light emitting units, such as those using chip scale packages (CSP), face challenges in miniaturization due to the need for lead frames and are limited in thickness, making them unsuitable for efficient lateral light emission without additional costly processes.
Innovation Solution
A light emitting unit design featuring a reflective structure with a recessed light transmitting body doped with fluorescent powder, allowing for lateral light emission without extending electrodes to the side surface, and optimizing the cross-section width and surface angles for improved luminous efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional CSP LED units are used for lateral emission, then miniaturization is achieved, but additional costly processes are required to extend electrodes to the lateral surface
Solution Approach 1:
Instead of extending electrodes from the top surface to the lateral surface (conventional approach), this patent inverts the electrode configuration by placing electrodes directly on the lateral surface of the chip. The reflective structure is positioned on the top surface to reflect light downward, while electrodes are exposed on the sides through a recessed design, eliminating the need for electrode extension processes.
Solution Approach 2:
The patent transitions from a conventional planar electrode layout to a three-dimensional configuration where electrodes are positioned on the lateral surface of the chip. The recessed structure creates vertical and lateral dimensions for electrode placement, allowing current injection from the sides while maintaining a compact overall structure without additional processing steps.
2Volume of moving object
If conventional CSP LED units are used for lateral emission, then miniaturization is achieved, but the thickness is limited by the width of the chip
Solution Approach 1:
The patent decouples the thickness dimension from the chip width constraint by using a recessed structure that extends vertically. The reflective structure is positioned on the top surface and reflects light downward through the light transmitting body, allowing the thickness to be independently optimized without being limited by the lateral chip dimensions.
Solution Approach 2:
The LED unit is segmented into distinct functional layers: a reflective structure on the top surface, a light transmitting body in the middle, and electrodes on the lateral surface. This segmentation allows each component to be optimized independently, with the thickness determined by the vertical arrangement of these segments rather than being constrained by the chip width.
3Loss of energy
If reflective structure with recessed light transmitting body is used, then luminous efficacy is improved, but device complexity increases
Solution Approach 1:
The patent merges the reflective structure and light transmitting body into an integrated recessed configuration. The reflective structure is positioned within a recess that also contains the light transmitting body, combining light reflection and transmission functions in a single structural element. This integration improves luminous efficacy by directing light efficiently while avoiding the need for separate components.
Solution Approach 2:
The recessed structure serves multiple functions simultaneously: it houses the reflective structure for light direction, contains the light transmitting body for light transmission, and provides a configuration for lateral electrode placement. This multi-functionality improves luminous efficacy through optimized light management while the unified structure avoids increasing overall device complexity.
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 design enhances luminous efficacy and reduces thickness, enabling more efficient lateral light emission compared to conventional CSP units, while avoiding the need for additional processing steps and maintaining a compact form factor.
Implementation Method 1
The light transmitting body is disposed within the recess and doped with fluorescent powder
Data Source
AI summary
A light emitting unit includes a reflective structure, a light transmitting body and a light emitting chip. The reflective structure has a recess formed by inner side surfaces thereof, and the reflective structure includes a side opening and a bottom opening corresponding to the recess. The side opening and the bottom opening are adjacent to each other, and the inner side surfaces are defined as a top surface and a surrounding side surface. The light transmitting body is disposed within the recess and doped with fluorescent powder. The light transmitting body includes a light emitting surface and an electrode exposing surface. The light emitting surface is corresponding to the side opening; and the electrode exposing surface is corresponding to the bottom opening. The light emitting chip is partially disposed within the light transmitting body and has a bottom, a top light emitting and side light emitting surfaces.