Fingerprint Display Multiplexing Reset and Scan Lines

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Solution Overview

Problem

The integration of optical fingerprint sensors with liquid crystal display panels results in a reduced aperture ratio due to the additional reset and select lines required for fingerprint recognition, leading to decreased display brightness.

Innovation Solution

Multiplexing the display scan line with the reset line and using a method to sequentially drive the display and select lines for both display and fingerprint sensing, allowing for the elimination of one reset line per optical fingerprint pixel unit, thereby improving the aperture ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If additional reset line and select line are provided to drive the fingerprint sensor, then fingerprint recognition function is enabled, but the aperture ratio of the display panel is greatly reduced

Engineering Contradiction:

Improvefingerprint recognition functionVSAvoidaperture ratio

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent merges the reset line function with the display scan line function by connecting the reset end of the fingerprint pixel unit to the display scan line. This allows the display scan line to serve dual purposes: driving display pixels and providing reset signals to fingerprint pixels, thereby eliminating the need for separate reset lines and improving aperture ratio.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The display scan line is designed to perform multiple functions: it drives display pixel units during display operation and simultaneously serves as the reset line for fingerprint pixel units during fingerprint sensing operation. This multi-functionality reduces the total number of required lines and increases the aperture ratio.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If additional reset line and select line are provided to drive the fingerprint sensor, then fingerprint recognition function is enabled, but display brightness decreases

Engineering Contradiction:

Improvefingerprint recognition functionVSAvoiddisplay brightness

Core Design Contradiction:

Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

By combining the reset line function with the display scan line function, the patent reduces the number of additional lines required for fingerprint sensing. This minimizes the impact on display brightness while maintaining full fingerprint recognition functionality.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11475701B2Fingerprint display device and integration integrated circuit and method for driving the same

Publication Date: 2022.10.18 FOCALTECH ELECTRONICS LTD

AI summary

A fingerprint display device has plural pixel rows. Each pixel row of n pixel rows in the plural pixel rows has plural display pixel units and plural fingerprint pixel units, where n is an integer greater than 1. The n pixel rows are driven at least by corresponding n display scan lines and n select lines for performing display and fingerprint detection. Each fingerprint pixel unit has a reset end and a select end. The reset end of the fingerprint pixel unit of i-th pixel row among the n pixel rows is connected to a corresponding display scan line among the n display scan lines, and the select end of the fingerprint pixel unit of i-th pixel row among the n pixel rows is connected to a corresponding select line among the n select lines, where i is an index value between 1 and n.