Display Substrate Light Shielding Pinhole Layout for Fingerprint Recognition
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Solution Overview
Problem
The integration of fingerprint recognition within OLED display panels leads to light leakage affecting the TFT device structure, causing degradation in display uniformity and grayscale accuracy due to the light-admitting design of imaging pinholes.
Innovation Solution
A display substrate design featuring an array layer with a light shielding layer containing imaging pinholes, where the pinholes' projections do not overlap with the active layer patterns of transistors, preventing light irradiation and photo-generated leakage currents, and optimizing the arrangement of pinholes to minimize impact on display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If imaging pinholes are formed in the light shielding layer for fingerprint recognition, then fingerprint recognition function is enabled, but light leakage occurs affecting the TFT device structure and degrading display uniformity and grayscale accuracy
Solution Approach 1:
The patent extracts the imaging pinholes from the conventional light shielding layer design and relocates them to a dedicated fingerprint recognition region. By separating the fingerprint recognition function from the display region, the light leakage is confined to areas where it does not affect the TFT device structure or display quality, thus enabling fingerprint recognition while maintaining display grayscale accuracy
Solution Approach 2:
The light shielding layer is designed with different properties in different regions: in the display region, it maintains complete light shielding to protect TFT structures, while in the fingerprint recognition region, it contains imaging pinholes to allow light passage for fingerprint sensing. This local differentiation resolves the contradiction by applying light shielding only where necessary
2Illumination intensity
If imaging pinholes are formed in the light shielding layer, then light can pass through for fingerprint imaging, but photo-generated leakage currents occur in the active layer pattern causing display uniformity degradation
Solution Approach 1:
The patent extracts the imaging pinholes from the general light shielding layer and places them specifically in the fingerprint recognition region where the active layer pattern is absent or minimized. This spatial separation ensures that light passing through the pinholes does not reach photo-sensitive regions that would generate leakage currents, thus maintaining display uniformity
Solution Approach 2:
The light shielding layer acts as an intermediary structure that selectively controls light transmission. It allows light to pass through imaging pinholes in the fingerprint region while blocking light in the display region, thereby mediating between the need for light transmission and the need to prevent photo-generated leakage currents
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 solution enhances display grayscale accuracy and uniformity by preventing light interference with the TFT structure, ensuring accurate fingerprint recognition without compromising display performance.
Implementation Method 1
a light shielding layer on a side of the array layer away from the base substrate... preventing light irradiation and photo-generated leakage currents
Implementation Method 2
a plurality of imaging pinholes are formed in the light shielding layer... a first orthographic projection of the imaging pinholes onto the base substrate and a second orthographic projection of an active layer pattern of the switching transistor in the array layer onto the base substrate do not overlap at least in part
Data Source
AI summary
A display substrate, a manufacturing method thereof, a display panel and a display device are provided. The display substrate includes: an array layer on a base substrate and a light shielding layer on a side of the array layer away from the base substrate, wherein the array layer includes a driving transistor and a switching transistor, the switching transistor is a transistor connected to a gate electrode of the driving transistor, a plurality of imaging pinholes are formed in the light shielding layer, and a first orthographic projection of the imaging pinholes onto the base substrate and a second orthographic projection of an active layer pattern of the switching transistor in the array layer onto the base substrate do not overlap at least in part.