Fingerprint Imaging Row Driver Circuit for Faster Authentication
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Solution Overview
Problem
Fingerprint authentication methods using light-emitting and light-receiving elements are time-consuming, leading to stress for the user and requiring improvements in speed and accuracy.
Innovation Solution
A semiconductor device with a light-emitting unit and imaging unit, incorporating a shift register circuit and latch circuits with transistors containing metal oxide in the channel formation region, allows for high-speed and accurate authentication by varying the transmission rates of scan signals in different modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fingerprint authentication methods using light-emitting and light-receiving elements are used, then authentication accuracy is achieved, but authentication time becomes excessively long
Solution Approach 1:
The patent implements dynamic scanning by varying the scanning speed across different regions of the imaging unit. The scan signal transmission rate is adjusted based on the position being scanned, allowing faster authentication in less critical areas while maintaining high accuracy in important regions, thus resolving the contradiction between speed and accuracy
Solution Approach 2:
The imaging unit is divided into multiple scanning regions with different priority levels. The patent segments the authentication process into multiple stages, scanning different portions of the fingerprint at different speeds, which enables overall time reduction while preserving accuracy in critical segments
2Productivity
If high-speed authentication is implemented, then authentication time is reduced, but authentication accuracy may deteriorate
Solution Approach 1:
Different regions of the imaging unit are assigned different scanning rates based on their importance. Critical regions maintain high scanning rates for accuracy, while non-critical regions use lower rates for speed, creating a local quality differentiation that balances overall performance
Solution Approach 2:
The patent employs periodic scanning with variable periods across different regions. By implementing periodic scan signals with different frequencies in different areas, the system achieves high-speed authentication overall while maintaining accuracy in periodic cycles for critical regions
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 semiconductor device enables fast and reliable fingerprint authentication with high accuracy by optimizing signal transmission rates, reducing authentication time without compromising precision.
Implementation Method 1
a finger is irradiated with light from a light-emitting element and light reflected by the finger is detected by a light-receiving element
Data Source
AI summary
A semiconductor device capable of performing authentication in a short time can be provided. The semiconductor device includes a light-emitting unit and an imaging unit. The imaging unit includes a row driver circuit, and the row driver circuit includes first to m latch circuits (m is an integer greater than or equal to 2) and first to m register circuits. A first start pulse signal is input to a first latch circuit and second start pulse signals are input to first to m latch circuits. Scan signals output from the first to (m−1)-th register circuits are input to the second to m-th latch circuits, respectively. The first latch circuit has a function of outputting one of the first start pulse signal and the second start pulse signal to the first register circuit on the basis of data held, and the second to m-th latch circuits have a function of outputting one of the scan signal and the second start pulse signal to the second to m-th register circuits on the basis of data held.