Display Substrate Fingerprint Integration via Planar PIN Photodiode
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Solution Overview
Problem
Existing display substrates with fingerprint identification capabilities face challenges of lower identification precision and poor integration level due to the collimation layer scheme or small aperture imaging scheme.
Innovation Solution
A display substrate with a fingerprint identification region is designed, featuring a base substrate with display units and a fingerprint identification unit located between adjacent display units. The fingerprint identification unit includes a fingerprint identification transistor and a planar PIN photodiode, with a gate insulating layer covering both transistors and the photodiode, enhancing integration and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the collimation layer scheme or small aperture imaging scheme is used for fingerprint identification, then the fingerprint identification function can be realized, but the identification precision is reduced and the integration level is poor
Solution Approach 1:
The patent merges the fingerprint identification unit with the display unit by integrating the photosensitive device and fingerprint identification transistor into the same substrate as the display elements. This consolidation eliminates the need for separate collimation layers or small aperture imaging components, thereby improving both identification precision and integration level simultaneously.
Solution Approach 2:
The patent transitions from traditional optical schemes requiring additional optical layers to a planar integration approach where the photosensitive device is positioned in the same plane as the display unit. This dimensional reconfiguration removes the need for complex optical path management and improves both precision and integration.
2Device complexity
If the fingerprint identification unit is integrated into the display substrate, then the integration level is improved, but the light propagation distance increases causing loss and reduced precision
Solution Approach 1:
The patent extracts the photosensitive device from traditional positions and repositions it adjacent to the display unit on the same substrate. This extraction and repositioning shortens the light propagation path while maintaining integration, thereby reducing light loss and improving precision without sacrificing integration level.
Solution Approach 2:
The patent creates a localized optical path between the display unit and photosensitive device by positioning them adjacent to each other. This local optimization ensures that light travels only the necessary minimal distance, reducing propagation loss while maintaining high integration level.
3Length of stationary object
If the display substrate is thinned to improve overall profile, then the thickness is reduced, but the integration of fingerprint identification components becomes more difficult
Solution Approach 1:
The patent combines the fingerprint identification components with the display components in a unified integrated structure on the same substrate. This merging allows both functions to coexist in a thinned substrate configuration, as the shared infrastructure eliminates the need for separate thick optical paths required by traditional schemes.
Solution Approach 2:
The patent adopts a planar integration architecture where all components are arranged in a two-dimensional configuration on the substrate surface. This dimensional approach enables thinning in the vertical direction while maintaining functional integration through lateral arrangements, thus reducing thickness without compromising integration capability.
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 improves fingerprint identification precision by reducing light propagation distance and loss, while facilitating the thinning of the display substrate without increasing overall thickness, thus enhancing integration and performance.
Implementation Method 1
a photosensitive device, a planar PIN photodiode
Data Source
AI summary
The present disclosure provides a display substrate and a manufacturing method thereof, and a display apparatus. The display substrate has a fingerprint identification region. The display substrate includes a base substrate; a display unit on the base substrate and including a display thin film transistor and a light-emitting device, a second electrode of the display thin film transistor being coupled to a first electrode of the light-emitting device; and a fingerprint identification unit at a gap between adjacent display units in the fingerprint identification region and including a fingerprint identification transistor and a photosensitive device, a first electrode of the fingerprint identification transistor being coupled to a second electrode of the photosensitive device. The display substrate further includes a gate insulating layer on a side of an active layer of the display thin film transistor and an active layer of the fingerprint identification transistor distal to the base substrate.