Display Driving Circuit Fingerprint Detection via High-Frequency Light Emission
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Solution Overview
Problem
Conventional fingerprint detection units in display products suffer from inaccurate fingerprint detection due to deteriorated switching TFTs and adverse effects on the display panel's aperture ratio, as they require multiple switching transistors that can be turned on or off erroneously, affecting performance.
Innovation Solution
A display driving unit circuit with a pixel driving circuit and a light-emission control signal generation circuit that operates in different modes for display and fingerprint detection, using a square-wave light-emission control signal with frequencies greater than 1000 Hz to enable fingerprint detection without additional switching transistors, thereby improving detection accuracy and aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If switching TFTs are used in conventional fingerprint detection units, then fingerprint detection can be achieved, but the detection accuracy deteriorates due to erroneous switching and the aperture ratio is adversely affected
Solution Approach 1:
The patent removes the switching TFT component from the fingerprint detection unit. Instead of using switching TFTs to control light emission, the invention uses a light emission control signal that directly controls the light emitting diode without requiring switching transistors, thereby eliminating the reliability issues associated with switching TFT performance deterioration
Solution Approach 2:
The light emitting diode serves dual functions: display function during normal operation and fingerprint detection function during detection mode. The same light emitting component is used for both purposes, eliminating the need for separate switching TFTs and achieving multi-functionality with reduced component count
2Ease of operation
If switching TFTs are used in fingerprint detection units, then light emission can be controlled, but the aperture ratio of the display panel is adversely affected
Solution Approach 1:
The switching TFT components are extracted and removed from the display structure. The light emission control is achieved through control signals rather than physical switching transistors, thereby increasing the aperture ratio by eliminating the area occupied by switching components
Solution Approach 2:
The light emitting diode performs both display and fingerprint detection functions, eliminating the need for additional switching TFTs that would reduce aperture ratio. The same structural elements serve multiple purposes, maximizing the usable display area
3Measurement precision
If high-frequency light emission is used for fingerprint detection, then detection accuracy is improved, but the light may be perceived by the human eye
Solution Approach 1:
The light emitting diode emits light in periodic pulses at high frequency during fingerprint detection. This periodic emission at frequencies above human visual perception threshold enables accurate fingerprint detection while preventing visible flicker or discomfort to users
Solution Approach 2:
The frequency parameter of the light emission is changed to exceed the human visual perception threshold (>1000 Hz) during fingerprint detection mode. By adjusting the emission frequency parameter, the system achieves both high detection accuracy and user comfort
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 enables accurate fingerprint detection without affecting the normal display, as the high-frequency light emission is not perceived by the human eye and improves the accuracy of fingerprint recognition while maintaining the display panel's aperture ratio.
Implementation Method 1
the pixel driving circuit controls the pixel to emit light having a frequency equal to the first frequency... and the pixel driving circuit controls the pixel to emit light having a frequency equal to the second frequency
Implementation Method 2
Each photovoltaic conversion element is arranged at a position corresponding to a non-light-emission region, coupled to a fingerprint current read line, and configured to convert a received optical signal into a fingerprint current signal
Data Source
AI summary
A display driving unit circuit, a driving method, a display driving circuit and a display device are provided. The display driving unit circuit includes a pixel driving circuit and a light-emission control signal generation circuit. The light-emission control signal generation circuit is coupled to the pixel driving circuit. The pixel driving circuit is to drive a pixel to emit light. The light-emission control signal generation circuit is to supply a display light-emission control signal to the pixel driving circuit at a display stage to enable the pixel in a displaying mode and supply a fingerprint detection light-emission control signal to the pixel driving circuit at a fingerprint detection stage to enable the pixel in a fingerprint detection light-emission mode at the fingerprint detection stage. The display stage and the fingerprint detection stage are different time periods.