AUO's full-screen fingerprint recognition technology

AUO exhibited a full range of cutting-edge display technologies at the 2019 SID Display Week in the United States from May 14 to 16, 2019, including the world's first full-screen optical in-cell fingerprint scanning LTPS display for smartphones, the world's smallest 4.2 mm through-hole design, and the in-cell touch LTPS display with the narrowest 1.0 mm bottom border.

AUO said that the 6-inch full-screen optical embedded fingerprint scanning LTPS display "announced" this time is the world's first fingerprint scanning technology that embeds an optical sensor in the LCD screen. It is equipped with AHVA and has full HD+ (1080 x 2160) and 403 PPI fine image quality. In addition, the full-screen fingerprint scanning area has a sensor resolution of 403 PPI and a fast response time of 30 ms, showing extremely accurate and smooth fingerprint sensing performance.

Generally speaking, the touch display panel and fingerprint recognition module of a smartphone are independent modules that are manufactured separately and then assembled together. Therefore, it is usually necessary to press the fingerprint on a specific fingerprint recognition area to achieve fingerprint recognition, such as the Home button of an Apple phone. In addition, this front-mounted fingerprint recognition module usually compresses the screen display area and reduces the screen-to-body ratio.

As mobile phone manufacturers continue to develop higher screen-to-body ratios, in order to perform fingerprint recognition throughout the entire screen to improve the integrity and screen-to-body ratio of the display device, AUO applied for an invention patent entitled "Fingerprint Recognition Module and Fingerprint Recognition Touch Display Using It" on May 24, 2019 (application number: 201910443473.1), and the applicant is AUO Optronics Corporation.

Based on the information currently disclosed by the patent, let us take a look at this full-screen fingerprint unlocking technology.

As shown in the figure above, it is a schematic diagram of the fingerprint recognition touch display invented in the patent. The fingerprint recognition touch display 100 includes a touch display panel 110, a controller 120 and a fingerprint recognition module 130. The touch display panel has a touch display area 112, and the controller is connected to the touch display panel to drive the fingerprint recognition module. The fingerprint recognition module is set in the touch display area to sense and recognize fingerprints.

The controller can control the partitioned driving of the fingerprint sensing electrodes in the fingerprint recognition module so that the fingerprint sensing electrodes in the corresponding area can sense the fingerprint of the finger in the fingerprint recognition mode. The fingerprint recognition module transmits the fingerprint sensing signal back to the controller for fingerprint recognition.

The above figure is a schematic diagram of a fingerprint recognition module, which includes a fingerprint sensor 131, a data input circuit 133, and a multiplexer array 141. The fingerprint sensor includes a plurality of fingerprint sensing electrodes 132. In order to drive the fingerprint sensor in different areas, the fingerprint sensing electrodes are divided into N groups, each group having M*Y fingerprint sensing electrodes.

For example, the fingerprint sensing electrodes are divided into 6 groups (N=6) in the short side direction of the fuselage, and each group has 180x1920 (M=180, Y=1920) fingerprint sensing electrodes. For each group of M*Y fingerprint sensing electrodes, the data input circuit is provided with N groups of M electrode wires in each group, which are independently connected to the corresponding groups of M rows of Y fingerprint sensing electrodes in each row.

As shown in the figure, the fingerprint sensing electrodes are divided into 6 groups, each group has 180 fingerprint sensing electrodes, and the data input circuit is formed with NxM electrode wires 134 and M data lines 135 arranged crosswise in the wiring area 114. The first electrode wire in each group is electrically connected to the first data line (Pin_1), the second electrode wire in each group is electrically connected to the second data line (Pin_2), and the Mth electrode wire in each group is electrically connected to the Mth data line (Pin_M), and they are arranged in sequence below the touch display area.

In addition, in order to achieve partitioned driving of the fingerprint sensor, the multiplexer array includes N switch circuits corresponding to N groups of electrode wires. Therefore, only one of the N switch circuits independently receives a connection signal (i.e., a pulse signal SP) to connect a group of electrode wires corresponding to this circuit, and the remaining N-1 switch circuits are in an open state.

The above is the touch display for full-screen fingerprint recognition invented by AUO. This fingerprint recognition module and the fingerprint recognition touch display using it can recognize fingerprints at any position in the touch display area without the need to set up an additional single-point fixed position fingerprint sensor. Therefore, the appearance will not be limited and the integrity of the display device can be improved, and the market demand for a high screen-to-body ratio can be met.