Laser Irradiation Mask with Reflective Layer for OLED Patterning
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Solution Overview
Problem
Laser radiation scattering in OLED display manufacturing causes undesired exposure of donor substrate regions to laser beams, leading to noise and interference during the LITI method, which affects the precision of patterning the light emitting layers.
Innovation Solution
A laser irradiation device with a mask pattern that includes a reflective layer on the non-transmissive region and is oriented at an inclined angle with respect to the laser beam axis, combined with an anti-reflective layer to prevent laser scattering, and a beam homogenizer to ensure precise patterning of the laser beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a mask pattern with a scattering layer is used in the non-transmissive region, then the mask can block direct laser radiation, but laser radiation scatters into portions of the donor substrate corresponding to the non-transmissive region, causing noise and interference
Solution Approach 1:
The patent applies this principle by converting the harmful scattered laser radiation into a beneficial reflected beam. The reflective layer is strategically positioned at an inclined angle (45 degrees) to intercept scattered laser radiation and redirect it away from the donor substrate. This transforms the harmful scattering effect into a useful reflection mechanism that actively prevents unwanted exposure, thereby improving patterning precision while maintaining mask functionality.
Solution Approach 2:
The patent introduces a new spatial dimension by tilting the reflective layer at an inclined angle relative to the mask pattern surface. This angular orientation creates a three-dimensional light path control mechanism, where scattered radiation is redirected along a different spatial trajectory. By adding this dimensional element (inclination angle), the system successfully separates the reflected beam from the direct laser path, preventing interference with the donor substrate while preserving the mask's blocking function.
2Device complexity
If the mask pattern surface is perpendicular to the laser beam axis, then the structure is simple, but laser radiation scatters into undesired regions of the donor substrate
Solution Approach 1:
The patent applies asymmetry by tilting the reflective layer at a specific angle (45 degrees) relative to the mask pattern surface, breaking the symmetric perpendicular arrangement. This asymmetric orientation causes the reflected laser radiation to deviate from the direct beam path and redirect away from the donor substrate. The asymmetric design successfully eliminates harmful scattering to undesired regions while maintaining relatively simple mask structure, resolving the contradiction between structural simplicity and harmful factor prevention.
3Manufacturing precision
If a reflective layer is added to the mask pattern at an inclined angle, then laser scattering is prevented, but the device complexity increases
Solution Approach 1:
The patent applies local quality by adding the reflective layer only to specific regions of the mask pattern where scattering control is needed, rather than making the entire mask complex. The reflective layer is positioned at inclined angles only in the non-transmissive regions, leaving other areas of the mask structure relatively simple. This localized approach achieves precise scattering control and improved patterning precision while minimizing the overall increase in 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 solution effectively prevents undesired exposure of the donor substrate to laser radiation, reducing noise and interference, and allows for precise formation of organic light emitting layers, enhancing the manufacturing process of OLED displays.
Implementation Method 1
the mask pattern includes a reflective layer on the non-transmissive region of the surface of the mask pattern that faces the laser source
Implementation Method 2
laser radiation scatters into portions of the donor substrate that correspond to the non-transmissive region of the mask pattern
Data Source
AI summary
A laser irradiation device and a method of manufacturing an organic light emitting diode display device using the same. The laser radiation device prevents the scattering of the laser light into portions of the donor substrate that correspond to non-transmissive regions of a mask pattern. To reduce the scattering, the mask pattern is designed so that 1) non-transmissive regions of a surface of the mask pattern that faces the laser source have a reflective layer, 2) the surface of the mask pattern that faces the laser source is oriented to have a certain angle with respect to the laser beam axis, and 3) a surface of the mask pattern that faces the donor substrate has an anti-reflective layer. Each of these design aspects of the mask pattern prevents laser light from being scattered and prevents irradiating portions of the donor substrate that corresponds to a non-transmissive region of the mask pattern.