Display device including biometric sensor and operating method thereof
A display device includes: a display panel including a first area having a first light transmissivity and a second area having a second light transmissivity higher than the first light transmissivity; a pressure sensor overlapping the first area; a light emitter overlapping the second area; a light receiver overlapping the second area and spaced from the light emitter; and a processor to control the light emitter and the pressure sensor, and to output a blood pressure signal on a basis of a pressure sensing signal from the pressure sensor and a light sensing signal from the light receiver.
1. A display device comprising:
a display panel including a first area having a first light transmissivity and a second area having a second light transmissivity higher than the first light transmissivity;
a pressure sensor overlapping the first area;
a light emitter overlapping the second area;
a light receiver overlapping the second area and spaced from the light emitter; and
a processor to control the light emitter and the pressure sensor, and to output a blood pressure signal on a basis of a pressure sensing signal from the pressure sensor and a light sensing signal from the light receiver.
2. The display device of claim 1 , wherein the pressure sensor comprises a pressure sensing module including:
pressure sensor units;
a transmission line to deliver a transmission signal to the pressure sensor units; and
receiving lines respectively corresponding to the pressure sensor units, to deliver received signals from the pressure sensor units as the pressure sensing signal.
3. The display device of claim 2 , wherein at least some of the pressure sensor units comprise:
a first electrode on a base substrate;
a second electrode on the base substrate and separated from the first electrode; and
a pressure sensing layer directly disposed on the first electrode and the second electrode.
4. The display device of claim 3 , wherein the first electrode is electrically connected to a corresponding receiving line of the receiving lines, and
the second electrode is electrically connected to the transmission line.
5. The display device of claim 3 , wherein
the first electrode comprises a first body unit and first branch units to extend from the first body unit in a first direction, and
the second electrode comprises a second body unit and second branch units to extend from the second body unit in an opposite direction to the first direction,
wherein the first branch units and the second branch units are alternately disposed in a second direction that intersects with the first direction.
6. The display device of claim 1 , wherein the processor comprises:
a first analog-to-digital converter to convert the pressure sensing signal to a digital pressure sensing signal;
a compensation unit to calculate a contact area on a basis of the digital pressure sensing signal, and to output a pressure-compensated signal in which the digital pressure sensing signal is compensated according to the contact area;
a second analog-to-digital converter to convert the light sensing signal to a digital light sensing signal; and
a blood pressure calculation unit to output the blood pressure signal on a basis of the pressure-compensated signal and the digital light sensing signal.
7. The display device of claim 6 , wherein the blood pressure calculation unit is configured to output a first control signal for the pressure sensor to sense a contact pressure of a user during a blood pressure measurement mode, and to output a second control signal for the light emitter to output light.
8. The display device of claim 6 , wherein the blood pressure calculation unit is configured to output, to the display panel, a message for requesting a magnitude of a contact pressure of a user to be gradually increased during a blood pressure measurement mode.
9. The display device of claim 6 , wherein the blood pressure calculation unit is configured to enter a blood pressure measurement mode, when the contact area is larger than a sensing requirement area.
10. The display device of claim 6 , wherein the compensation unit is configured to: reduce the digital pressure sensing signal by a prescribed ratio, when the contact area is larger than a first reference value, and increase the digital pressure sensing signal by a prescribed ratio, when the contact area is smaller than a second reference value.
11. The display device of claim 6 , wherein the blood pressure calculation unit is configured to sense a change in a light sensing level of the digital light sensing signal, while a contact pressure of a user gradually increases and thus a pressure sensing level of the pressure-compensated signal increases.
12. The display device of claim 11 , wherein the blood pressure calculation unit is configured to:
calculate the pressure sensing level, which corresponds to a point at which the light sensing level is a maximum, as a mean arterial pressure;
calculate the pressure sensing level of the pressure-compensated signal, which corresponds to a first ratio of the light sensing level corresponding to the mean arterial pressure, as a systolic blood pressure;
calculate the pressure sensing level, which corresponds to a second ratio of the light sensing level corresponding to the mean arterial pressure, as a diastolic blood pressure; and
output the blood pressure signal corresponding to each of the systolic blood pressure and the diastolic blood pressure.
13. The display device of claim 1 , wherein the light emitter comprises a first light emitting module and a second light emitting module separately disposed from each other.
14. The display device of claim 1 , wherein the pressure sensor has a shape substantially enclosing at least a portion of the light emitter and the light receiver.