Hybrid sensing touchscreen apparatus capable of light touch sensing and physical touch sensing and method of driving the same

• US 9,256,317 B2
• Filed: 12/27/2013
• Issued: 02/09/2016
• Est. Priority Date: 12/28/2012
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Ahn, Seung-eon, Song, I-hun, Jeon, Yong-woo, Ahn, Ji-hoon, Lee, Seung-hyup
• Primary Examiner(s): Davis, David D
• Application Number:
  US14/141,785
• Publication Number:
  US 20140184570A1
• Time in Patent Office: 774 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• 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 3/042 by opto-electronic means
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: H01L 27/14678 Contact-type imagers
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2017/9606 using one electrode only per touch switch

Abstract

A touchscreen apparatus includes pixel rows including pixels configured to display an image, a touch-sensing unit configured to sense a physical touch, light-sensing unit configured to sense incident light, a first sensor gate line configured to provide a first gate signal for activating the light-sensing unit and resetting the touch-sensing unit, a second sensor gate line configured to provide a second gate signal for activating the touch-sensing unit and resetting the light-sensing unit, and a reset circuit configured to provide a common voltage to the pixels based on the operation of at least one of the light-sensing unit and the touch-sensing unit.

Claims

1. A touchscreen apparatus comprising:

pixel rows including pixels configured to display an image;

a touch-sensing unit configured to sense a physical touch and a light-sensing unit configured to sense incident light, the touch-sensing unit and the light-sensing unit being between two adjacent pixel rows and configured to operate based on first and second gate signals;

a first sensor gate line connected to the light-sensing unit and the touch-sensing unit and configured to provide the first gate signal for activating the light-sensing unit and resetting the touch-sensing unit;

a second sensor gate line connected to both the light-sensing unit and the touch-sensing unit and configured to provide the second gate signal for activating the touch-sensing unit and resetting the light-sensing unit; and

a reset circuit configured to provide a common voltage to the pixels based on the operation of at least one of the light-sensing unit and the touch-sensing unit.

2. The touchscreen apparatus of claim 1, further comprising:

a common electrode connected to the pixels.

3. The touchscreen apparatus of claim 2, wherein the reset circuit comprises:

a common voltage line;

a reset transistor configured to provide the common voltage to the pixels based on the operation of at least one of the light-sensing unit and the touch-sensing unit; and

a reset gate line configured to provide a third gate signal to the reset transistor,

wherein a gate of the reset transistor is connected to the reset gate line, a drain of the reset transistor is connected to the common voltage line, and a source of the reset transistor is connected to the common electrode.

4. The touchscreen apparatus of claim 3, wherein the common voltage line is configured to maintain a constant common voltage.

5. The touchscreen apparatus of claim 2, wherein the touch-sensing unit comprises:

a coupling capacitor connected between the common electrode and the second sensor gate line;

a source follower transistor configured to generate a sensing current corresponding to a voltage change of the common electrode;

a switch transistor configured to read the sensing current;

a reset transistor configured to initialize a voltage of the common electrode; and

a sensor data line configured to output the sensing current.

6. The touchscreen apparatus of claim 5, wherein a gate of the source follower transistor is connected to the common electrode, a source of the source follower transistor is connected to a drain of the switch transistor, and a drain of the source follower transistor is connected to the second sensor gate line.

7. The touchscreen apparatus of claim 5, wherein a gate of the switch transistor is connected to the second sensor gate line and a source of the switch transistor is connected to the sensor data line, and

wherein a gate of the reset transistor is connected to the first sensor gate line, a source of the reset transistor is connected to the common electrode, and a drain of the reset transistor is connected to the second sensor gate line.

8. The touchscreen apparatus of claim 1, further comprising:

display gate lines connected to the respective pixel rows to provide display gate signals for sequentially activating the pixel rows.

9. The touchscreen apparatus of claim 8, wherein each of the pixels includes a pixel cell and a driving transistor configured to switch the respective pixel cell on and off, a gate of the driving transistor being connected to the display gate line and a source of the driving transistor being connected to the respective pixel cell.

10. The touchscreen apparatus of claim 9, further comprising:

a display data line connected to a drain of the driving transistor.

11. The touchscreen apparatus of claim 8, wherein the touchscreen apparatus is configured to, after activating one of two display gate lines connected to two pixel rows which are adjacent to the light-sensing unit and the touch-sensing unit, sequentially activate the first sensor gate line, the second sensor gate line, and the other of the two display gate lines.

12. The touchscreen apparatus of claim 1, wherein the light-sensing unit comprises:

a light sensor transistor configured to generate a drain current in an off state according to an intensity of light;

a switch transistor configured to read the drain current in the off state of the light sensor transistor; and

a sensor data line configured to output the drain current.

13. The touchscreen apparatus of claim 12, wherein a gate of the switch transistor is connected to the first sensor gate line, a drain of the switch transistor is connected to a source of the light sensor transistor, and a source of the switch transistor is connected to the sensor data line, and

wherein a gate of the light sensor transistor is connected to the second sensor gate line and a drain of the light sensor transistor is connected to the first sensor gate line.

14. The touchscreen apparatus of claim 12, wherein the light-sensing unit comprises multiple light sensor transistors connected in parallel.

15. The touchscreen apparatus of claim 12, wherein the light sensor transistor is an oxide semiconductor transistor including a channel layer having an oxide semiconductor material.

16. A method of driving a touchscreen apparatus, the method comprising:

activating a first pixel row including pixels;

activating one of a light-sensing unit for sensing incident light and a touch-sensing unit for sensing a physical touch, the light-sensing unit and the touch-sensing unit being adjacent to the first pixel row, and resetting the other of the light-sensing unit and the touch-sensing unit;

resetting the activated one of the light-sensing unit and the touch-sensing unit and activating the reset other of the light-sensing unit and the touch-sensing unit; and

activating a second pixel row including additional pixels, the second pixel row being adjacent to the light-sensing unit and the touch-sensing unit,

applying a common voltage to the pixels when the first and second pixel rows are in an activated state, and prohibit providing the common voltage to the pixels when the light-sensing unit or the touch-sensing unit is in an activated state.

17. The method of claim 16, wherein the pixels in the first and second pixel rows are commonly connected to one common electrode.

18. The method of claim 17, further comprising:

applying a common voltage to a common voltage line, the touchscreen apparatus including a reset transistor connected between the common voltage line and the common electrode, and a reset gate line configured to provide a gate signal to the reset transistor; and

switching the reset transistor to provide the common voltage to the pixels in an activated state of the pixels and prohibit providing the common voltage to the pixels in the activated state of one of the light-sensing unit and the touch-sensing unit.

19. The method of claim 18, further comprising:

maintaining a constant common voltage; and

activating the reset gate line is activated in the activated state of the pixels to turn on the reset transistor and deactivating the reset gate line in the activated state of the light-sensing unit or the touch-sensing unit to turn off the reset transistor.

20. The method of claim 16, wherein the touchscreen apparatus comprises first and second sensor gate lines connected to the light-sensing unit and the touch-sensing unit,

the light-sensing unit is activated and the touch-sensing unit is reset in an activated state of the first sensor gate line, and

the touch-sensing unit is activated and the light-sensing unit is reset in an activated state of the second sensor gate line.