LED Mounting Substrate Reflective Layer for Thin Mini-LED Boards
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Solution Overview
Problem
Existing LED substrates face challenges in achieving sufficient reflectance while maintaining thinness and adaptability to mini-LEDs and μ-LEDs, with issues such as warpage, complex coating steps, and reduced reflectivity due to larger light reflection layers and ink bleeding.
Innovation Solution
A substrate with a base material and a reflective layer made of a curable resin composition including titanium oxide, where the reflective layer has a storage elastic modulus of 4.0 GPa or less, and openings are disposed at equal spacings with specific dimensions and area rates to enhance reflectance and prevent warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the light reflection layer is made larger to improve reflectivity, then reflectance is improved, but warpage of the substrate occurs
Solution Approach 1:
The invention changes the material parameters of the reflective layer by specifying a storage elastic modulus of 4.0 GPa or less and using specific resin compositions (acrylic, vinyl, or polyurethane resins with defined molecular weights and functional groups). These parameter changes allow the reflective layer to be more compliant, reducing substrate warpage while maintaining adequate reflectance through optimized titanium oxide content (20-80 parts by mass per 100 parts resin) and layer thickness (10-50 μm).
Solution Approach 2:
The invention creates a composite reflective layer combining organic resin materials with inorganic titanium oxide particles. This composite structure provides both the mechanical compliance needed to prevent warpage (through the flexible resin matrix) and the optical reflectance properties (through the titanium oxide particles), resolving the contradiction between reflectance and substrate stability.
2Illumination intensity
If a two-layer coating structure is used to form the light reflection layer, then reflectivity can be improved, but the formation steps become complicated
Solution Approach 1:
The invention merges the intimate contact layer and light reflection layer into a single integrated reflective layer formed by one-layer coating. The resin composition simultaneously provides both the adhesive bonding function (previously requiring a separate intimate contact layer) and the light reflection function (previously requiring a separate reflective layer), thereby simplifying the coating process while maintaining adequate reflectivity through optimized titanium oxide content.
3Illumination intensity
If the gap between the opening and LED is narrowed to increase reflectivity, then reflectance is improved, but ink bleeding causes deviation from designed values
Solution Approach 1:
The invention changes the rheological parameters of the resin composition by specifying viscosity ranges (100-1000 cP at 25°C) and molecular weight parameters (number-average molecular weight 10,000-1,000,000). These parameter changes optimize the ink's flow characteristics to prevent bleeding into narrow gaps while maintaining adequate reflectance through controlled titanium oxide distribution.
Solution Approach 2:
The invention replaces reliance on mechanical precision (wide gaps to prevent ink bleeding) with material property control (viscosity and surface tension optimization). By substituting mechanical design constraints with material science solutions, the invention enables narrow gaps (improving reflectance) while maintaining manufacturing precision through controlled resin composition rather than dimensional tolerances.
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 solution provides a substrate with improved reflectance and reduced warpage, enabling effective mounting of mini-LEDs and μ-LEDs on a thin base material with enhanced reflectivity and simplified coating processes.
Implementation Method 1
a reflective layer that is layered on an upper region of the base material, wherein the reflective layer includes a cured product of a curable resin composition including a curable resin and titanium oxide
Implementation Method 2
the reflective layer includes a cured product of a curable resin composition including a curable resin and titanium oxide
Data Source
AI summary
Provided is a substrate for mounting an LED that can be applied to a thin base material and can result in a sufficient reflectance, particularly a substrate for mounting an LED, adaptable to a mini-LED and a μ-LED. In the substrate for mounting an LED, including a base material and a reflective layer that is layered on an upper region thereof, plural openings are disposed at generally equal spacings in longitudinal and lateral directions in the reflective layer, respectively, the reflective layer is the cured product of a curable resin composition including a curable resin and titanium oxide, the cured product has a storage elastic modulus of 4.0 GPa or less at 25° C., the spacings between the opening and the opening adjacent thereto in the longitudinal direction and the lateral direction are not less than twice the lengths of the opening in the longitudinal direction and the lateral direction, respectively, and the total area rate of the openings with respect to the area of the reflective layer is 0.1% or more and 9.0% or less.