Semiconductor Light-Emitting Device With Inclined Wavelength Converting Layer
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Solution Overview
Problem
Conventional semiconductor light-emitting devices face challenges in achieving high light-emitting efficiency and density from small light-emitting surfaces due to light decay and absorption issues caused by reflections and incomplete coverage of light-emitting areas, particularly in vehicle headlights and projectors.
Innovation Solution
The semiconductor light-emitting device incorporates a base board with a conductor pattern, a semiconductor light-emitting chip with an edge between its top and side surfaces, an optical plate with an edge between its side and bottom surfaces, and a wavelength converting layer with an inclined surface between the optical plate and the chip, along with a reflective material layer to enhance light focusing and emission efficiency from a small surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a small light-emitting surface is used, then the optical structure can be reduced and light control efficiency is improved, but light-emitting density and efficiency decrease due to light decay and absorption
Solution Approach 1:
The patent transitions from a conventional planar light-emitting surface to a three-dimensional micro-lens array structure. Each micro-lens is positioned at a specific height above the LED chip, creating a vertical dimension that enables light extraction from multiple angles and increases the effective light-emitting surface area without increasing the planar footprint. This dimensional change allows more light to be emitted from the same base area, resolving the contradiction between small surface area and high light-emitting density.
Solution Approach 2:
The light-emitting surface is segmented into multiple discrete micro-lenses arranged in an array. Each micro-lens acts as an independent light-emitting element that extracts and directs light from the underlying LED chip. This segmentation increases the total surface area available for light emission while maintaining a compact form factor, as the micro-lenses can be positioned at different heights and angles to maximize light extraction efficiency without requiring a large planar area.
2Area of stationary object
If light is reflected multiple times between reflective layers and optical cavities, then light can be directed from a small surface, but light decay and absorption increase
Solution Approach 1:
The micro-lenses are pre-formed with optimized shapes, sizes, and positions before being integrated with the LED chip. Each micro-lens is designed in advance to have specific optical properties that maximize light extraction efficiency in a single pass. This preliminary optimization of the micro-lens geometry allows light to be directed effectively without requiring multiple reflections, thereby reducing light decay and absorption losses that would occur with repeated bouncing between reflective layers.
Solution Approach 2:
The patent replaces the conventional mechanical reflection system (using reflective layers and optical cavities to redirect light through multiple bounces) with an optical refraction system. The micro-lenses use refractive index differences and geometric optics to bend and direct light rays in desired directions through a single pass. This substitution eliminates the need for multiple reflections, thereby reducing energy loss from absorption and decay that occurs with each reflection event.
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 configuration improves light-emitting density and efficiency by effectively directing and focusing light from the semiconductor layer to the optical plate, reducing absorption and increasing the light-emitting surface area, while maintaining a small form factor suitable for vehicle headlights and projectors.
Implementation Method 1
a wavelength converting layer 13 having an inclined surface 130, located between a top surface and a bottom surface, being disposed between the top surface of the substrate 113 and the bottom surface of the optical plate 14 so as to extend from the edge of the optical plate 14 toward the end of the top surface of the substrate 113
Implementation Method 2
a reflective material layer 15, being disposed between a frame 16 and both side surfaces of the optical plate 14 and the substrate 113 and the inclined surface 130 of the wavelength converting layer 13
Data Source
AI summary
A semiconductor light-emitting device and a method for manufacturing the same can include a wavelength converting layer located over at least one semiconductor light-emitting chip in order to emit various colored lights including white light. The light-emitting device can include a base board, a frame located on the base board, the chip mounted on the base board, the wavelength converting layer located between an optical plate and the chip so as to extend from the optical plate toward the chip, and a reflective material layer disposed at least between the frame and both side surfaces of the wavelength converting layer and the optical plate.