Capacitive Ultrasonic Sensors and Display Devices Using the Same

• US 20090235750A1
• Filed: 03/24/2008
• Published: 09/24/2009
• Est. Priority Date: 03/24/2008
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: CHANG, Ming-Wei, GWO, Tsung-Ju, DENG, Hsu-Cheng
• Granted Patent: US 7,856,883 B2
• Time in Patent Office: Days
• US Class Current: 73/627
• CPC Class Codes: G06F 2203/04101 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/043 using propagating acoustic waves

Abstract

A capacitive ultrasonic device is capable of detecting an object and providing information regarding an orientation of the object. The capacitive ultrasonic device includes a power source configured to generate a voltage signal, an array of sensor elements, each of the sensor elements being configured to generate an ultrasonic wave during a first period of the voltage signal and detect whether a wave is reflected from the object during a second period of the voltage signal when the voltage signal is applied thereto, and a control unit configured to activate a first portion of the array of sensor elements through the power source, and activate a second portion of the array of sensor elements when at least one of the first portion of the sensor elements detects a wave reflected from the object.

Claims

1. A capacitive ultrasonic device capable of detecting an object and providing information regarding an orientation of the object, the capacitive ultrasonic device comprising:

a power source configured to generate a voltage signal;

an array of sensor elements, each of the sensor elements being configured to generate an ultrasonic wave during a first period of the voltage signal and detect whether a wave is reflected from the object during a second period of the voltage signal when the voltage signal is applied thereto; and

a control unit configured to activate a first portion of the array of sensor elements through the power source, and activate a second portion of the array of sensor elements when at least one of the first portion of the sensor elements detects a wave reflected from the object.

2. The capacitive ultrasonic device of claim 1, wherein the voltage signal includes an alternating-current (AC) component and a direct-current (DC) component during the first period, and includes the DC component during the second period.

3. The capacitive ultrasonic device of claim 1, wherein the control unit identifies whether the magnitude of a wave reflected from the object is greater than or equal to a threshold.

4. The capacitive ultrasonic device of claim 1, wherein the control unit identifies whether the magnitude of a wave reflected from the object is greater than or equal to a threshold for a predetermined period.

5. The capacitive ultrasonic device of claim 1, wherein the control unit is configured to identify a position of each of the first portion of the sensor elements and a distance between the each of the first portion of the sensor elements and the object if the each of the first portion of the sensor elements detects a wave reflected from the object.

6. The capacitive ultrasonic device of claim 5 further comprising a memory configured to store the position and distance related to the each of the first portion of the sensor elements.

7. The capacitive ultrasonic device of claim 5, wherein the control unit is coupled to a display driver and provides information regarding the position and distance related to the each of the first portion of the sensor elements to the display driver.

8. The capacitive ultrasonic device of claim 2, wherein the control unit is configured to change the magnitude of a DC component of the voltage signal.

9. A capacitive ultrasonic device capable of detecting an object and providing information regarding an orientation of the object, the capacitive ultrasonic device comprising:

a power source configured to generate a voltage signal including a direct-current (DC) component;

an array of sensor elements coupled to the power source, each of the sensor elements being configured to generate an ultrasonic wave with an effective distance when the voltage signal is applied thereto; and

a control unit configured to activate at least one of the array of sensor elements through the power source, and change the effective distance of the ultrasonic wave by changing the magnitude of the DC component of the voltage signal.

10. The capacitive ultrasonic device of claim 9, wherein the control unit is configured to identify a position of each of the at least one of the sensor elements and a distance between the each of the at least one of the sensor elements and the object if the each of the at least one of the sensor elements detects a wave reflected from the object.

11. The capacitive ultrasonic device of claim 9, wherein each of the sensor elements is configured to generate an ultrasonic wave during a first period of the voltage signal and detect whether a wave is reflected from the object during a second period of the voltage signal when the voltage signal is applied thereto.

12. The capacitive ultrasonic device of claim 11, wherein the voltage signal includes an alternating-current (AC) component and the DC component during the first period, and includes the DC component during the second period.

13. The capacitive ultrasonic device of claim 9, wherein the control unit is configured to identify whether the magnitude of a wave reflected from the object is greater than or equal to a threshold.

14. The capacitive ultrasonic device of claim 9, wherein the control unit is configured to identify whether the magnitude of a wave reflected from the object is greater than or equal to a threshold for a predetermined period.

15. The capacitive ultrasonic device of claim 10 further comprising a memory configured to store the position and distance related to the each of the at least one of the sensor elements.

16. The capacitive ultrasonic device of claim 9, wherein the control unit is configured to activate at least another one of the sensor elements when the at least one of the sensor elements detects a wave reflected from the object.

25. The capacitive ultrasonic device of claim 10, wherein the control unit is coupled to a display driver and sends to the display driver information on the position of the each of the at least one of the sensor elements and the distance between the each of the at least one of the sensor elements and the object.

17. A capacitive ultrasonic device capable of detecting an object and providing information regarding an orientation of the object, the capacitive ultrasonic device comprising:

a power source configured to generate a voltage signal including a direct-current (DC) component;

a capacitive ultrasonic sensor coupled to the power source, the capacitive ultrasonic sensor including an array of sensor elements each of which is configured to generate an ultrasonic wave with an effective distance when the voltage signal is applied thereto; and

a control unit configured to identify a position of each of the sensor elements and a distance between the each of the sensor elements and the object if the each of the sensor elements detects a wave reflected from the object.

18. The capacitive ultrasonic device of claim 17, wherein the voltage signal includes an alternating-current (AC) component and the DC component during a first period, and includes the DC component during a second period.

19. The capacitive ultrasonic device of claim 18, wherein each of the sensor elements is configured to generate an ultrasonic wave during the first period of the voltage signal and detect whether a wave is reflected from the object during the second period of the voltage signal when the voltage signal is applied thereto.

20. The capacitive ultrasonic device of claim 17, wherein the control unit identifies whether the magnitude of a wave reflected from the object is greater than or equal to a threshold.

21. The capacitive ultrasonic device of claim 17, wherein the control unit identifies whether the magnitude of a wave reflected from the object is greater than or equal to a threshold for a predetermined period.

22. The capacitive ultrasonic device of claim 17 further comprising a memory configured to store the position and distance related to the each of the sensor elements.

23. The capacitive ultrasonic device of claim 17, wherein the control unit is configured to activate a portion of the array of sensor elements after at least one of the sensor elements detects a wave reflected from the object.

24. The capacitive ultrasonic device of claim 17, wherein the control unit is configured to change the effective distance of the ultrasonic wave by changing the magnitude of the DC component of the voltage signal.

26. The capacitive ultrasonic device of claim 17, wherein the control unit is coupled to a display driver and sends to the display driver information on the position of the each of the at least one of the sensor elements and the distance between the each of the at least one of the sensor elements and the object.