Display Panel Capacitor Structure for In-Display Fingerprint Sensing
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Solution Overview
Problem
Conventional fingerprint sensors using oxide thin film transistors, such as IGZO, have narrower sensitivity ranges, leading to worse recognition effects due to their inability to sense visible light with wavelengths between 400 to 760 nanometers, resulting in poor fingerprint recognition in display devices.
Innovation Solution
The implementation of an array substrate configuration that includes a first thin film transistor and a capacitor, where the photosensitive pattern in the capacitor senses light, enhancing the sensitometric characteristics of the thin film transistor, and using a second gate as a capacitor polar plate to decrease the thickness of the array substrate, thereby improving fingerprint recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxide thin film transistors (IGZO) are used in fingerprint sensors, then electron mobility and stability are improved, but sensitivity range is reduced leading to worse recognition effect
Solution Approach 1:
The patent combines oxide thin film transistors (for stability and electron mobility) with amorphous silicon photosensitive layers (for broad visible light sensitivity) into a hybrid structure. The oxide TFT serves as the switching transistor while the amorphous silicon layer serves as the photosensitive layer in the capacitor, merging the advantages of both materials to achieve both reliability and wide sensitivity range.
Solution Approach 2:
The invention uses composite material structure combining oxide semiconductor (IGZO) and amorphous silicon in the same device. The oxide layer provides stable electrical characteristics while the amorphous silicon photosensitive layer provides broad spectral response across visible wavelengths, creating a composite system that overcomes the limitations of either material alone.
2Manufacturing precision
If oxide thin film transistors are used, then manufacturing precision is improved, but fingerprint recognition effectiveness is reduced due to narrow sensitivity range
Solution Approach 1:
The patent merges oxide TFT technology (providing manufacturing precision and stability) with amorphous silicon photosensitive technology (providing broad light sensitivity for accurate fingerprint detection). The combination allows the device to maintain precise manufacturing characteristics while achieving effective fingerprint recognition across the visible spectrum.
3Device complexity
If conventional capacitor structure is used, then device complexity is maintained, but sensitivity range is limited
Solution Approach 1:
The patent makes the capacitor structure multi-functional by using amorphous silicon as the photosensitive layer that serves both as the capacitor dielectric and as the light-sensing element. This allows the same structure to provide both capacitive function and broad-spectrum photosensitivity, increasing adaptability without significantly increasing device complexity.
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 sensitometric characteristics of the thin film transistor, enhancing fingerprint recognition effectiveness and reducing the thickness of the array substrate, which simplifies manufacturing processes and improves display area and resolution.
Implementation Method 1
the photosensitive pattern in the capacitor senses light
Data Source
AI summary
A display panel, a manufacturing method thereof, and a display device are provided. Through a configuration of a capacitor in the display panel, where the capacitor is connected to a first thin film transistor, a photosensitive pattern in the capacitor senses light, such that when the light varies, a varying charge quantity of the photosensitive pattern in the capacitor varies current of the first thin film transistor, increasing a sensitometric characteristic of the first thin film transistor, and increasing fingerprint recognition effect, and a second gate is configured to be a capacitor polar plate, decreasing a thickness of an array substrate.