Touch Panel White Color Filter Photosensitivity
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Solution Overview
Problem
Conventional light sensitive touch panels have reduced photosensitivity due to the placement of photosensitive elements under blue color filters, which absorb ambient light, thereby reducing the sensitivity of the photosensitive thin film transistors.
Innovation Solution
Integrating a photosensitive element under a white color filter, which allows direct radiation of ambient light without passing through a colored layer, enhancing the photosensitivity by using a white sub-pixel with a transparent organic resin layer and no color pigments, dyes, or colorants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the photosensitive element is arranged under the blue color filter, then the touch panel can display blue light, but the photosensitivity of the photosensitive element is reduced due to light absorption by the blue color filter
Solution Approach 1:
The patent divides the color filter layer into separate red, green, and blue color filters, and introduces a white color filter as a separate layer. This segmentation allows the photosensitive element to be positioned under the white color filter rather than the blue color filter, enabling it to receive full ambient light without being filtered by the blue color filter's light-absorbing properties.
Solution Approach 2:
The white color filter acts as an intermediary layer that allows ambient light to pass through to the photosensitive element without absorbing significant light energy. This intermediary structure enables the photosensitive element to maintain high photosensitivity while still being part of the display structure.
2Illumination intensity
If a color filter is placed over the photosensitive element, then the display can achieve color reproduction, but the photosensitive element receives reduced light intensity
Solution Approach 1:
The white color filter serves multiple functions: it acts as a color filter for display purposes and simultaneously serves as a light-transmitting layer for the photosensitive element. This multi-functionality allows the same structure to fulfill both display color reproduction and photosensitivity requirements without compromising either function.
3Productivity
If the photosensitive element is positioned under the blue color filter, then the structure is simplified, but the photo current production is reduced
Solution Approach 1:
The patent introduces a new dimensional arrangement by placing the white color filter as a separate layer above the photosensitive element, rather than integrating the color filter directly over the photosensitive element. This dimensional change in layer stacking allows ambient light to reach the photosensitive element more effectively, increasing photo current production.
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
This configuration increases the production of photo current and improves the overall photosensitivity of the touch panel, maintaining image color integrity and enhancing resolution and brightness.
Implementation Method 1
When the photosensitive thin film transistor is radiated by an ambient light, a photo current is produced
Data Source
AI summary
A touch panel is provided. The touch panel comprises a first substrate and a second substrate facing the first substrate. A black matrix is formed on the first substrate defining a plurality of sub-pixel areas, a plurality of color filters on the sub-pixel areas. A photosensitive sensitive element is formed on the second substrate. The color filters comprise a red color filter, a green color filter, a blue color filter and a white color filter over the photosensitive element.