US-12620360-B2 - Display device including integrated optical sensors and sensing control circuitry

US12620360B2US 12620360 B2US12620360 B2US 12620360B2US-12620360-B2

Abstract

A display device including: a display panel including scan write lines, sensing lines, pixels respectively connected to the scan write lines, and optical sensors respectively connected to the scan write lines and the sensing lines; a scan driver configured to sequentially output scan write signals to the scan write lines in response to a scan control signal; a read-out circuit configured to receive light sensing signals of the optical sensors from the sensing lines in response to a first sampling signal; and a timing controller configured to control the scan driver and the read-out circuit, wherein an interval between pulses of the first sampling signal has a first horizontal period, and an interval between pulses of each of the scan write signals has a second horizontal period.

Inventors

Chul Kim

Assignees

SAMSUNG DISPLAY CO., LTD.

Dates

Publication Date: 20260505
Application Date: 20240513
Priority Date: 20220722

Claims (20)

1 . A display device, comprising: a display panel comprising scan write lines, sensing lines, pixels respectively connected to the scan write lines, and optical sensors respectively connected to the scan write lines and the sensing lines; a scan driver configured to sequentially output scan write signals to the scan write lines in response to a scan control signal; a read-out circuit configured to receive light sensing signals of the optical sensors from the sensing lines in response to a first sampling signal; and a timing controller configured to control the scan driver and the read-out circuit, wherein each of the optical sensors comprises: a photoelectric conversion element comprising an anode electrode and a cathode electrode connected to a driving voltage line; a first sensing transistor comprising a gate electrode connected to the anode electrode of the photoelectric conversion element; a reset transistor configured to connect a reset voltage line receiving a reset voltage to the anode electrode of the photoelectric conversion element in response to a reset signal separate from the scan write signals to reset the anode electrode to the reset voltage, the reset signal having a gate-on voltage; and a second sensing transistor configured to connect the first sensing transistor to a corresponding one of the sensing lines in response to a corresponding one of the scan write signals input thereto, wherein a source electrode of the first sensing transistor is configured to receive an initialization voltage from an initialization voltage line separate from the reset voltage line.
2 . The display device of claim 1 , wherein an interval between pulses of the first sampling signal corresponds to a first horizontal period, an interval between pulses of each of the scan write signals corresponds to a second horizontal period.
3 . The display device of claim 2 , wherein the first horizontal period is longer than the second horizontal period.
4 . The display device of claim 3 , further comprising a reset driver configured to output the reset signal for turning on each reset transistor of the optical sensors.
5 . The display device of claim 3 , wherein the read-out circuit comprises: an amplifier connected to the corresponding one of the sensing lines and comprising an operational amplifier; a sampling unit comprising a first sampling capacitor configured to hold a voltage of one of the light sensing signals in response to the first sampling signal; and an analog-digital (AD) converter configured to convert the held light sensing signal voltage into digital data.
6 . The display device of claim 5 , wherein each of the second sensing transistors is turned on in response to a corresponding one of the scan write signals to output a sensing signal voltage through the sensing line to which it is connected, and each of the sensing signal voltages is held in the first sampling capacitor in response to the first sampling signal.
7 . The display device of claim 6 , wherein the first sampling signal has a first period in which the first sampling capacitor is turned on and a second period in which the first sampling capacitor is turned off.
8 . The display device of claim 7 , wherein in the first period, the first sampling capacitor accumulates and holds at least two sensing signal voltages among the sensing signal voltages.
9 . The display device of claim 7 , wherein the first period is longer than the second horizontal period.
10 . The display device of claim 5 , wherein the sampling unit further comprises a second sampling capacitor configured to hold a noise voltage in response to a second sampling signal, and the second sampling signal and the first sampling signal are sequentially turned on.
11 . The display device of claim 10 , wherein an interval between pulses of each of the second sampling signals is equal to the first horizontal period.
12 . The display device of claim 2 , wherein the optical sensors comprise a first optical sensor and a second optical sensor, and the scan write lines comprise: a first scan write line configured to provide an nth scan write signal (n being a positive integer) to a first pixel among the pixels connected to the first optical sensor and the first optical sensor; and a second scan write line configured to provide an (n+1)th scan write signal to a second pixel among the pixels connected to the second optical sensor and the second optical sensor, wherein the second horizontal period between the nth scan write signal and the (n+1)th scan write signal is shorter than the first horizontal period of the first sampling signal.
13 . The display device of claim 2 , wherein the timing controller outputs the first sampling signal having a turn-on voltage during a first period in a first mode for detecting a fingerprint and having a turn-on voltage during a second period in a second mode for detecting a blood pressure, and the first period is shorter than the second period.
14 . The display device of claim 13 , wherein the first period is shorter than the second horizontal period.
15 . The display device of claim 14 , wherein the second horizontal period is shorter than the second period.
16 . A display device, comprising: a display panel comprising a pixel, a first optical sensor, and a second optical sensor; first scan write lines configured to provide a first scan write signal to the pixel and the first optical sensor; second scan write lines configured to provide a second scan write signal to the pixel and the second optical sensor; a scan driver configured to output the first scan write signal to the first scan write lines and the second scan write signal to the second scan write lines; a read-out circuit configured to receive a first light sensing signal from the first optical sensor through a first sensing line in response to a first sampling signal, and receive a second light sensing signal from the second optical sensor through a second sensing line; and a timing controller configured to output the first sampling signal to the read-out circuit, wherein the first sampling signal has a first horizontal period defining an interval between adjacent first sampling pulses, and a pulse width of each of the first scan write signal and the second scan write signal has a second horizontal period defining an interval between adjacent scan write pulses, the second horizontal period being different from the first horizontal period, wherein the timing controller is further configured to output a feedback reset signal to the read-out circuit prior to each first sampling signal, an interval between adjacent pulses of the feedback reset signal defining the first horizontal period, wherein a turn-on of the first sampling signal is maintained longer than the second horizontal period.
17 . The display device of claim 16 , wherein the first horizontal period is longer than the second horizontal period.
18 . The display device of claim 17 , wherein the first sampling signal has a first period having a turn-on voltage and a second period having a turn-off voltage, and the read-out circuit is configured to accumulate and receive the first and second light sensing signals in the first period.
19 . The display device of claim 18 , wherein the read-out circuit comprises: an amplifier connected to the first and second sensing lines and comprising an operational amplifier; a sampling unit comprising a first sampling capacitor configured to accumulate and hold voltages of the first and second light sensing signals during the first period of the first sampling signal; and an analog-digital (AD) converter configured to convert the held voltages of the first and second light sensing signals into digital data.
20 . An electronic device, comprising: a display panel comprising scan write lines, sensing lines, pixels respectively connected to the scan write lines, and optical sensors respectively connected to the scan write lines and the sensing lines; a scan driver configured to sequentially output scan write signals to the scan write lines in response to a scan control signal; a read-out circuit configured to receive light sensing signals of the optical sensors from the sensing lines in response to a first sampling signal; and a timing controller configured to control the scan driver and the read-out circuit, wherein the first sampling signal has a first horizontal period, and each of the scan write signals has a second horizontal period defining an interval between adjacent scan write pulses, wherein the first and second horizontal periods overlap each other and the first horizontal period is longer than the second horizontal period, wherein the timing controller is further configured to output a feedback reset signal to the read-out circuit prior to each first sampling signal, an interval between adjacent pulses of the feedback reset signal defining the first horizontal period, wherein a turn-on of the first sampling signal is maintained longer than the second horizontal period.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. patent application Ser. No. 18/109,330 filed on Feb. 14, 2023, which claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2022-0091208 filed on Jul. 22, 2022 in the Korean Intellectual Property Office, the disclosures of which are incorporated by reference herein in their entireties. 1. TECHNICAL FIELD The present disclosure relates to a display device. 2. DESCRIPTION OF THE RELATED ART A display device, which is an output device for displaying images, is currently used in various devices. For example, display devices are employed in various electronic devices such as smartphones, digital cameras, laptop computers, tablet personal computers (tablet PCs), navigation devices, and smart televisions. In the case of portable display devices such as smartphones, tablet PCs, and the like, various functions such as image capturing, fingerprint recognition, facial recognition, and the like are provided. Recently, methods have been developed to more easily obtain biometric information related to health characteristics of a user. For example, attempts have been made to replace a traditional blood pressure measuring device that uses an oscillometric method with a portable blood pressure measuring device. However, the portable blood pressure measuring device generally requires its own separate light source, sensor, and display, and it must be accompanied by the user's portable smartphone or tablet PC, which can be inconvenient. SUMMARY Embodiments of the present disclosure provide a display device capable of detecting light sensing signals at a high speed and at a frequency equal or similar to the driving frequency of an image display panel, and detecting pulse wave signals according to the light sensing signals without an error according to the frequency or the detection speed of the light sensing signals. According to an embodiment of the disclosure, there is provided a display device including: a display panel including scan write lines, sensing lines, pixels respectively connected to the scan write lines, and optical sensors respectively connected to the scan write lines and the sensing lines; a scan driver configured to sequentially output scan write signals to the scan write lines in response to a scan control signal; a read-out circuit configured to receive light sensing signals of the optical sensors from the sensing lines in response to a first sampling signal; and a timing controller configured to control the scan driver and the read-out circuit, wherein an interval between pulses of the first sampling signal has a first horizontal period, and an interval between pulses of each of the scan write signals has a second horizontal period. The first horizontal period is longer than the second horizontal period. Each of the optical sensors includes: a photoelectric conversion element including an anode electrode and a cathode electrode connected to a voltage line; a first sensing transistor including a gate electrode connected to the anode electrode of the photoelectric conversion element; a reset transistor configured to connect a reset voltage line to the anode electrode of the photoelectric conversion element in response to a reset signal; and a second sensing transistor configured to connect the first sensing transistor to a corresponding one of the sensing lines in response to the scan write signal input thereto. The display device may further include a reset driver configured to output the reset signal for turning on each reset transistor of the optical sensors. The read-out circuit includes: an amplifier connected to the corresponding one of the sensing lines and comprising an operational amplifier; a sampling unit comprising a first sampling capacitor configured to hold a voltage of one of the light sensing signals in response to the first sampling signal; and an analog-digital (AD) converter configured to convert the held light sensing signal voltage into digital data. Each of the second sensing transistors is turned on in response to a corresponding one of the scan write signals to output a sensing signal voltage through the sensing line to which it is connected, and each of the sensing signal voltages is held in the first sampling capacitor in response to the first sampling signal. The first sampling signal has a first period in which the first sampling capacitor is turned on and a second period in which the first sampling capacitor is turned off. In the first period, the first sampling capacitor accumulates and holds at least two sensing signal voltages among the sensing signal voltages. The first period is longer than the second horizontal period. The sampling unit further includes a second sampling capacitor configured to hold a noise voltage in response to a second sampling signal, and the second sampling signal and the first sampling signal are sequentially turned on. An interval between pulses of