Touchscreen display device and related method

• US 9,052,770 B2
• Filed: 01/09/2013
• Issued: 06/09/2015
• Est. Priority Date: 08/24/2012
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Hong, Won-ki, Nam, Seungho, Jang, Hyeonyong
• Primary Examiner(s): PATEL, PREMAL R
• Application Number:
  US13/737,676
• Publication Number:
  US 20140055406A1
• Time in Patent Office: 881 Days
• Field of Search: 345173-179, 178 1801- 1809
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/0428 by sensing at the edges of the touch surface the interruption of optical paths, e.g. an illumination plane, parallel to the touch surface which may be virtual sensing beam interruptions in a planar beam grid of an optical touch-screen G06F3/0421
• CPC Class Codes: G06F 3/0433 in which the acoustic waves are either generated by a movable member and propagated within a surface layer or propagated within a surface layer and captured by a movable member

Abstract

A display device includes a display element. The display device may include a touch substrate overlapping the display element and may overlap an external object when the external object provides a touch to the display device. The display device may include a first angle sensor disposed at a first corner of the touch substrate for determining a first touch angle related to the touch. The display device may include a second angle sensor disposed at a second corner of the touch substrate for determining a second touch angle related to the touch. The display device may include a force sensor disposed at the first corner of the touch substrate for determining a distance related to the touch. The display device may include a computation part configured to determine a touch coordinate associated with the touch based on the first touch angle, the second touch angle, and the distance.

Claims

1. A display device, comprising:

a display element configured to display images;

a touch substrate at which a touch is generated, wherein the touch substrate overlaps the display element;

a first angle sensor disposed at a first corner of the touch substrate for determining a first touch angle related to the touch;

a second angle sensor disposed at a second corner of the touch substrate for determining a second touch angle related to the touch;

a force sensor disposed at the first corner of the touch substrate corresponding to the first angle sensor for determining a distance from the force sensor to the touch; and

a computation part configured to determine a touch coordinate associated with the touch based on the first touch angle determined by the first angle sensor, the second touch angle determined by the second angle sensor, and the distance determined by the force sensor.

2. The display device of claim 1, wherein the force sensor is further configured to calculate a magnitude of a sensor force received at the force sensor, and wherein at least one of the force sensor and the computation part is further configured to calculate a magnitude of a touch force received at the touch point and related to the touch based on the distance and the sensor force.

3. The display device of claim 1, wherein the first angle sensor includes an infrared camera, and

wherein the infrared camera comprises a light output portion for outputting an output infrared light and a light input portion for receiving a reflected infrared light that is resulted from the output infrared light.

4. The display device of claim 1, wherein the force sensor comprises:

a sensor resistor having a resistance that is configured to vary according to a sensor force received at the sensor resistor;

a filter resistor having a constant resistance value and connected in series to the sensor resistor; and

a force sensing part connected to a node that is connected between the sensor resistor and the filter resistor,

wherein the sensor resistor and the filter resistor are configured for dividing a reference voltage to provide a division voltage at the node, and wherein the force sensing part is configured to determine the sensor force using a value of the a division voltage.

5. The display device of claim 4, wherein the force sensor senses an arrival time of a surface acoustic wave generated by the touch and the touch distance is calculated by:

D=v×

Δ

t

wherein D indicates the touch distance, v indicates a transfer speed of the surface acoustic wave, Δ

t indicates the arrival taken for the surface acoustic wave to reach the force sensor.

6. The display device of claim 1, wherein the first angle sensor overlaps the force sensor in a direction perpendicular to a surface of the touch substrate.

7. The display device of claim 1, further comprising:

a frame disposed on the touch substrate, having an opening, and including an inner wall for reflecting infrared light provided by at least one of the first angle sensor and the second angle sensor.

8. The display device of claim 7, wherein the frame includes a cavity, and wherein the first angle sensor is disposed inside the cavity.

9. The display device of claim 7, further comprising:

a reflection plate disposed at the inner wall for reflecting the infrared light.

10. The display device of claim 1, further comprising:

a supporter disposed at the second corner of the touch substrate, wherein a height of the supporter is equal to a height of the force sensor.

11. The display device of claim 1, wherein the computation part comprises:

a candidate coordinate calculator configured to calculate a first candidate coordinate related to the touch using two of the first touch angle, the second touch angle, and the distance, the candidate coordinate calculated being further configured to calculate a second candidate coordinate;

a coordinate calculator configured to select the touch coordinate from the first candidate coordinate and the second candidate coordinate using the remaining one of the first touch angle, the second touch angle, and the touch distance; and

a touch force calculator configured to calculate the touch force based on the touch distance and the sensor force.

12. The display device of claim 11, wherein the candidate coordinate calculator calculates the candidate coordinate by:

xy=(D·

cos(θ

),D·

sin(θ

))

wherein xy indicates the candidate coordinate, D indicates the touch distance, and θ

indicates the first touch angle.

13. The display device of claim 12, wherein the coordinate calculator is configured to select the touch coordinate from the first candidate coordinate and the second candidate coordinate using the second touch angle.

14. The display device of claim 11, wherein the candidate coordinate calculator calculates the candidate coordinate by:

15. The display device of claim 14, wherein the coordinate calculator is configured to select the touch coordinate from the first candidate coordinate and the second candidate coordinate using the distance.

16. The touch display device of claim 11, wherein the touch force calculator calculates the touch force by:

F1=F2×

(1+a·

D²)

wherein F1 indicates the touch force, F2 indicates the sensor force, a indicates a proportional constant, and D indicates the touch distance.

17. The display device of claim 1, comprising:

a base substrate, wherein the display element is disposed between the touch substrate and the base substrate, and wherein the force sensor is disposed between the touch substrate and the base substrate.

18. The display device of claim 17, wherein the first angle sensor is external to the touch substrate and overlaps the base substrate in a direction perpendicular to the base substrate.

19. The display device of claim 17, further comprising:

a polarization plate overlapping the touch substrate, wherein a space between the touch substrate and the polarization plate is filled with air.

20. The display device of claim 17, further comprising:

a reflection layer including a first portion disposed at and overlapping a first surface of the touch substrate and disposed between the touch substrate and the base substrate for reflecting a first part of an infrared light provided by the first angle sensor.

21. The display device of claim 20, wherein the reflection layer further includes a second portion perpendicular to the first portion and overlapping a second surface of the touch substrate for reflecting a second part of an infrared light provided by the first angle sensor.

22. A method for operating a display device, the method comprising:

sensing, using a first angle sensor disposed at a first corner of a touch substrate, a first touch angle related to a touch;

sensing, using a second angle sensor disposed at a second corner of the touch substrate, a second touch angle related to the touch;

determining, using a force sensor disposed at the first corner of the touch substrate corresponding to the first angle sensor, a distance from the touch to the force sensor;

determining, using the force sensor, a magnitude of a sensor force related to the touch and received at the force sensor;

determining, using a computation part, a touch coordinate related to the touch using the first touch angle sensed by the first angle sensor, the second touch angle sensed by the second angle sensor, and the distance determined by the force sensor; and

determining, using at least one of the computation part and the force sensor, a magnitude of a touch force related to the touch using the magnitude of the sensor force and the distance.

23. The method of claim 22, further comprising:

calculating a first candidate coordinate using the computation part and two of the first touch angle, the second touch angle, and the distance without using a remaining one of the first touch angle, the second touch angle, and the distance;

calculating a second candidate coordinate using at least the computation part; and

selecting the touch coordinate from the first candidate coordinate and the second candidate coordinate using the computation part and the remaining one of the first touch angle, the second touch angle, and the distance.