Display Substrate Light-Shielding Layout for Regular Fingerprint Channels
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Solution Overview
Problem
Existing optical fingerprint recognition systems face challenges in maintaining the accuracy and regularity of light-transmitting channels due to sagging or tilting of conductive light-shielding patterns at via holes, leading to irregular shapes and reduced recognition accuracy.
Innovation Solution
The implementation of a display substrate with a conductive light-shielding layer that includes via holes on both sides of light-transmitting holes, coupled with a pixel circuit layer and insulating layers, ensures that the conductive light-shielding pattern remains in a horizontal plane, preventing sagging and improving the accuracy of texture recognition by using separate active and dummy portions for signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive light-shielding layer with via holes is used to connect pixel circuits, then electrical connectivity is achieved, but the conductive pattern sags or tilts at via holes causing irregular light-transmitting channels
Solution Approach 1:
The patent applies preliminary anti-action by introducing a light-shielding layer that proactively compensates for the sagging effect before it degrades the light-transmitting channel quality. The light-shielding layer is positioned to offset the downward displacement of conductive patterns at via holes, thereby preventing the formation of irregular light channels rather than merely correcting them after the fact.
Solution Approach 2:
The light-shielding layer serves as an intermediary element between the conductive light-shielding layer and the texture recognition unit. It mediates the optical path by compensating for the sagging conductive patterns, ensuring that light transmitted through the via holes maintains proper geometry and intensity for accurate fingerprint recognition.
2Ease of operation
If via holes are created in the conductive light-shielding pattern for electrical connection, then pixel circuits can be electrically connected, but the shape of the light-transmitting channel becomes irregular
Solution Approach 1:
The light-shielding layer is designed in advance to counteract the geometric distortion caused by via holes. By positioning the light-shielding pattern to overlap with the via hole regions, it pre-compensates for the expected sagging, thereby maintaining regular light-transmitting channel geometry while allowing necessary electrical connections.
Solution Approach 2:
The light-shielding layer applies local quality by providing targeted compensation only in the regions where via holes are located. The light-shielding pattern is strategically positioned to address the specific geometric distortion at via hole locations without affecting other areas of the light-transmitting channel, thereby maintaining overall channel regularity.
3Object-affected harmful factors
If the conductive light-shielding pattern is made continuous for better shielding, then light shielding effectiveness improves, but the sagging at via holes becomes more pronounced
Solution Approach 1:
The light-shielding layer acts as an intermediary that decouples the contradiction between continuous conductive patterns and their sagging. It provides the necessary light shielding compensation independently, allowing the conductive light-shielding layer to maintain its continuous structure for effective shielding while the light-shielding layer corrects the alignment issues caused by via holes.
Solution Approach 2:
The patent segments the shielding function into two independent layers: the conductive light-shielding layer that provides continuous electrical connectivity and light shielding, and the separate light-shielding layer that specifically addresses the alignment and sagging issues. This segmentation allows each layer to optimize its respective function without compromising the other.
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 enhances the accuracy and reliability of texture recognition by maintaining the regularity of light-transmitting channels and preventing signal transmission errors, thereby improving the overall performance of optical fingerprint recognition systems.
Implementation Method 1
the conductive light-shielding layer has a first light-transmitting hole located in the photosensitive region
Implementation Method 2
The conductive light-shielding pattern is coupled with a source electrode or a drain electrode of the first thin film transistor through the first via hole
Implementation Method 3
after display light emitted from the display apparatus is incident on a finger of the user, the display light is reflected by valleys and ridges of the finger and incident onto the texture recognition unit(s) through the pinholes in the light-shielding layer
Data Source
AI summary
A display substrate has an active area which includes a photosensitive region with a light-transmitting channel. The display substrate includes a base, a pixel circuit layer, a first insulating layer and a conductive light-shielding layer. The pixel circuit layer includes pixel circuits and at least one pixel circuit includes a first thin film transistor and a second thin film transistor. The first insulating layer has a first via hole. The conductive light-shielding layer includes a conductive light-shielding pattern that has a first light-transmitting hole. Orthogonal projections of the first light-transmitting hole and of a gap region between the first thin film transistor and the second thin film transistor have a first overlapping region, which the light-transmitting channel penetrates. The conductive light-shielding pattern is coupled with a source electrode or a drain electrode of the first thin film transistor through the first via hole.