Light-Emitting Device Resin Layer Viscosity Control
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Solution Overview
Problem
Existing methods for manufacturing light emitting devices using semiconductor light emitting elements and phosphors suffer from uneven color and delamination issues between resin layers, which affect the reliability and performance of the devices.
Innovation Solution
A manufacturing method involving the formation of a first resin layer with a specific viscosity on the light emitting element, followed by a second resin layer with a lower viscosity containing phosphor, which is applied before curing the first resin layer, allowing for a uniform phosphor layer formation and preventing delamination, with the first resin layer having a curved surface to conform to the light emitting element's shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a phosphor layer is formed by covering the light emitting element with phosphor to convert wavelength, then white light emission is achieved, but uneven color and inaccurate color occur due to phosphor deposition on conductive wires and non-uniform distribution
Solution Approach 1:
A resin layer is introduced as an intermediary medium between the light emitting element and the phosphor. The phosphor is mixed with the resin to form a phosphor-resin mixture layer, which prevents direct phosphor deposition on conductive wires and ensures uniform phosphor distribution throughout the layer, thereby achieving uniform color emission.
2Adaptability or versatility
If multiple resin layers are formed sequentially to create functional layers, then device functionality is improved, but delamination occurs between resin layers due to interface formation
Solution Approach 1:
Multiple functional layers (protective layer and phosphor layer) are merged into a single integrated phosphor-resin mixture layer. This eliminates the interface between separate resin layers, preventing delamination while maintaining both the protective function and the wavelength conversion function in one unified structure.
3Power
If phosphor is deposited directly on the light emitting element, then wavelength conversion is efficient, but color unevenness occurs due to phosphor aggregation on conductive structures
Solution Approach 1:
The phosphor-resin mixture is applied with different local properties: the resin provides a uniform distribution matrix that prevents phosphor aggregation on conductive wires, while the phosphor particles maintain their wavelength conversion efficiency. The resin acts as a local medium that controls phosphor positioning without affecting the phosphor's optical conversion function.
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 method effectively reduces uneven color and ensures high reliability by maintaining the tackiness of the first resin layer, allowing for a uniform phosphor layer and preventing delamination between resin layers, resulting in improved optical path uniformity and device performance.
Implementation Method 1
a phosphor layer to absorb at least a part of light emitted from the light emitting element (1) to emit light of a wavelength different from that of the absorbed light
Implementation Method 2
forming a first resin layer with a first resin in which viscosity is adjusted to a first viscosity on a light emitting face of the light emitting element... forming a second resin layer with a second resin containing a phosphor in which viscosity is adjusted to a second viscosity lower than the first viscosity on the first resin layer before curing the first resin layer
Data Source
Figure 1
Figure 2A~2C
Figure 3
AI summary
Provided are a method for producing a light-emitting device and a light emitting device which can effectively minimize color irregularities, and which is highly reliable, being devoid of resin separation. The method for producing a light-emitting device is a method for producing a light-emitting device having a light-emitting element, and a phosphor layer that absorbs at least some of the light output by the light-emitting element and emits light of a different wavelength than the absorbed light, wherein the method includes: a first resin layer formation step in which a first resin layer that defines a predetermined shape for a phosphor layer is formed on the light-emitting surface of the light-emitting element by a first resin that has been adjusted to a first viscosity; a second resin layer formation step in which, prior to curing of the first resin layer, a second resin layer is formed over the first resin layer, using a second resin that includes a phosphor and that has been adjusted to a second viscosity lower than the first viscosity; and a curing step in which the first resin layer and the second resin layer are cured.