Light-emitting Device Recess Light-absorbing Member
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Solution Overview
Problem
Light-emitting devices with a black light-absorbing layer on the light emission surface face reduced light extraction efficiency due to external light reflection, which affects contrast and performance.
Innovation Solution
A light-emitting device design featuring a package with a recess at the light extraction surface, where the light-emitting element is mounted on an upward-facing surface and a light-absorbing member is positioned in the recess, spaced apart from the element, with an exposed surface facing upward to minimize external light reflection without compromising light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a black light-absorbing layer is disposed on the light emission surface, then the influence of external light reflection is reduced and contrast is improved, but light extraction efficiency is reduced
Solution Approach 1:
The light-absorbing layer is segmented into two distinct parts: (1) a light-absorbing member disposed in the recess at the light extraction surface, and (2) a light-absorbing layer formed on the mounting surface of the LED chip. This segmentation allows the light-absorbing member in the recess to block external light reflection without interfering with light extraction from the LED chip, while the light-absorbing layer on the mounting surface absorbs stray light. The recess structure creates a spatial separation that resolves the contradiction between blocking external light and maintaining light extraction efficiency.
2Measurement precision
If a black light-absorbing layer is disposed on the light emission surface, then contrast between turned-on and turned-off LED chips is improved, but light extraction efficiency is reduced
Solution Approach 1:
The light-absorbing structure is divided into a recess-containing light-absorbing member and a light-absorbing layer on the mounting surface. This segmentation enables the recess structure to provide contrast enhancement by blocking external light reflection from the light extraction surface, while the light-absorbing layer on the mounting surface absorbs stray light without affecting the primary light extraction path from the LED chip.
Solution Approach 2:
The recess structure acts as an intermediary element between the external environment and the light extraction surface. By placing the light-absorbing member within the recess, external light is absorbed before it can reflect off the light extraction surface and interfere with the displayed image, thereby improving contrast without requiring a light-absorbing layer that would block the light extraction path.
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 effectively reduces the influence of external light reflection on the light-emitting device, maintaining high light extraction efficiency and improving contrast, particularly useful for display applications.
Implementation Method 1
a light-absorbing member disposed in the recess, spaced apart from the light-emitting element, and having an exposed surface facing upward toward the light extraction surface
Data Source
AI summary
A light-emitting device includes a package, at least one light-emitting element and a light-absorbing member. The package defines a recess having an opening at a light extraction surface of the package. A part of the recess is defined by an upward-facing surface of the package. The light-emitting element is mounted on the upward-facing surface of the package. The light-absorbing member is disposed in the recess, spaced apart from the light-emitting element, and having an exposed surface facing upward toward the light extraction surface, the exposed surface being exposed from the upward-facing surface of the package with the exposed surface and the upward-facing surface of the package being on the same plane.