White Photoresist Anti-Reflection in OLED Display Panels
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Solution Overview
Problem
Display panels, particularly those using organic light emitting devices, face issues with light reflection that degrade image quality and reduce luminance efficiency due to the reflection of incident light by metal elements and electrodes, which is exacerbated by the removal of polarizing plates or films intended to reduce reflection.
Innovation Solution
A display panel design incorporating a substrate with thin film transistors, subpixels with color filters, and a non-transparent white photoresist that covers the thin film transistor area and white subpixel area, along with a light absorbing layer in a film to reduce external light reflection, while maintaining high light transmittance and luminance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If polarizing plates or films are used to reduce reflection, then reflection is reduced, but device complexity and cost increase
Solution Approach 1:
The patent extracts the light reflection reduction function from the polarizing plate/film and implements it directly through the photoresist layer formed on the substrate. The photoresist layer with specific refractive index (1.5-1.8) provides anti-reflection properties without requiring separate polarizing components, thereby reducing device complexity while maintaining reflection reduction effectiveness.
Solution Approach 2:
The photoresist layer acts as an intermediary between the substrate and the external environment, providing anti-reflection functionality. By positioning the photoresist layer directly on the substrate with appropriate refractive index, it mediates the interaction between incident light and the underlying structures, reducing reflection without needing polarizing plates or films.
2Device complexity
If polarizing plates or films are removed to simplify the device, then device complexity is reduced, but light reflection increases
Solution Approach 1:
The patent extracts the anti-reflection function from separate polarizing components and integrates it into the photoresist layer. This allows the device to operate without polarizing plates or films while maintaining low reflection through the photoresist's specific refractive index properties.
Solution Approach 2:
The patent changes the refractive index parameter of the photoresist layer to specific ranges (1.5-1.8 for visible light, or 1.6-2.0 for broader spectrum) to optimize anti-reflection performance. This parameter optimization enables the photoresist layer to provide effective reflection reduction without requiring polarizing components.
3Object-affected harmful factors
If a light absorbing layer is added to reduce reflection, then reflection is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent merges the anti-reflection function with the photoresist layer that is already part of the manufacturing process. By forming the photoresist layer with specific refractive index during the existing fabrication steps, the anti-reflection functionality is integrated without requiring separate light-absorbing layer deposition processes, thus avoiding additional manufacturing complexity.
Solution Approach 2:
The photoresist layer serves multiple functions: it provides structural support, defines pixel patterns, and simultaneously provides anti-reflection properties through its specific refractive index. This multi-functionality eliminates the need for separate dedicated anti-reflection layers, simplifying the manufacturing process.
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 reduces external light reflection, enhancing visibility and luminance efficiency by absorbing incident and reflected light, thereby improving the overall performance of the display panel without the need for polarizing plates or films.
Implementation Method 1
a white photoresist formed in a subpixel area of the white color filter, and formed to cover the TFT area
Implementation Method 2
a non-transparent photoresist positioned on the thin film transistor
Data Source
AI summary
A display panel is discussed. The display panel includes a substrate having a thin film transistor (TFT) area having a plurality of thin film transistors (TFTs), and a pixel area having a plurality of subpixels that correspond to the plurality of thin film transistors; a plurality of color filters respectively formed in each area of the plurality of subpixels, the plurality color filters comprising each of red color (R), green color (G), blue color (B) and white color; and a white photoresist formed in a subpixel area of the white color filter, and formed to cover the TFT area.