Touch display module and electronic device using same
A touch display module utilizing touch recognition by ultrasound includes display unit on substrate, barrier layer on other side of the substrate, and an ultrasound fingerprint sensing unit on the barrier layer. An acoustic impedance of the display unit, the barrier layer, and the ultrasonic fingerprint sensing unit are not all the same, and the differences in impedances enable recognition of touches by analysis of reflected ultrasound. The disclosure also provides an electronic device using the touch display module.
1. A touch display module, comprising:
a display unit;
a barrier layer, the barrier layer being adhered to a surface of the display unit; and
an ultrasonic fingerprint sensing unit, the ultrasonic fingerprint sensing unit being adhered to a surface of the barrier layer away from the display unit;
wherein each of the display unit, the barrier layer, and the ultrasonic fingerprint sensing unit has a different acoustic impedance, and a value of the acoustic impedance of the barrier layer is between a value of the acoustic impedance of the display unit and a value of the acoustic impedance of the ultrasonic fingerprint sensing unit,
wherein the value of the sound impedance of the barrier layer is approximately a square root of a product of the acoustic impedance of the display unit and the acoustic impedance of the ultrasonic fingerprint sensing unit.
2. The touch display module of claim 1 , further comprising a display area, wherein part of the display unit is located in the display area, and the ultrasonic fingerprint sensing unit is located in the display area.
3. The touch display module of claim 1 , wherein the barrier layer comprises a conductive layer and an adhesive layer, the adhesive layer comprises a first adhesive layer and a second adhesive layer, and the conductive layer is between the first adhesive layer and the second adhesive layer.
4. The touch display module of claim 3 , wherein the display unit and the ultrasonic fingerprint sensing unit are bonded to the barrier layer by the adhesive layer.
5. The touch display module of claim 3 , wherein an acoustic impedance of the conductive layer is between an acoustic impedance of the first adhesive layer and an acoustic impedance of the second adhesive layer.
6. The touch display module of claim 3 , wherein the adhesive layer has an optical density greater than or equal to 4 and a Young's modulus greater than 3 MPa.
7. The touch display module of claim 3 , wherein the conductive layer is made of a conductive material, and a surface resistance of the conductive layer is less than 200 mΩ.
8. The touch display module of claim 1 , wherein the display unit comprise a substrate, the barrier layer is adhered to a surface of the substrate, a projection area of the barrier layer on the substrate is less than or equal to an area of the substrate, and a projection area of the ultrasonic fingerprint sensing unit on the substrate is less than or equal to a projection area of the barrier layer on the substrate.
9. An electronic device, comprising a main body and a touch display module in the main body, the touch display module, comprising:
a display unit;
a barrier layer, the barrier layer being adhered to a surface of the display unit; and
an ultrasonic fingerprint sensing unit, the ultrasonic fingerprint sensing unit being adhered to a surface of the barrier layer away from the display unit;
wherein each of the display unit, the barrier layer, and the ultrasonic fingerprint sensing unit has a different acoustic impedance, and a value of the acoustic impedance of the barrier layer is between a value of the acoustic impedance of the display unit and a value of the acoustic impedance of the ultrasonic fingerprint sensing unit,
wherein the sound impedance of the barrier layer is approximately a square root of a product of the acoustic impedance of the display unit and the acoustic impedance of the ultrasonic fingerprint sensing unit.
10. The electronic device of claim 9 , wherein the touch display module further comprising a display area, part of the display unit is located in the display area, and the ultrasonic fingerprint sensing unit is located in the display area.
11. The electronic device of claim 9 , wherein the barrier layer comprises a conductive layer and an adhesive layer, the adhesive layer comprises a first adhesive layer and a second adhesive layer, and the conductive layer is between the first adhesive layer and the second adhesive layer.
12. The electronic device of claim 11 , wherein the display unit and the ultrasonic fingerprint sensing unit are bonded to the barrier layer by the adhesive layer.
13. The electronic device of claim 11 , wherein an acoustic impedance of the conductive layer is between an acoustic impedance of the first adhesive layer and an acoustic impedance of the second adhesive layer.
14. The electronic device of claim 11 , wherein the adhesive layer has an optical density greater than or equal to 4 and a Young's modulus greater than 3 MPa.
15. The electronic device of claim 11 , wherein the conductive layer is made of a conductive material, and a surface resistance of the conductive layer is less than 200 mΩ.
16. The electronic device of claim 9 , wherein the display unit comprise a substrate, the barrier layer is adhered to a surface of the substrate, a projection area of the barrier layer on the substrate is less than or equal to an area of the substrate, and a projection area of the ultrasonic fingerprint sensing unit on the substrate is less than or equal to a projection area of the barrier layer on the substrate.