Semiconductor device, touch panel, and electronic device

• US 10,268,326 B2
• Filed: 06/16/2016
• Issued: 04/23/2019
• Est. Priority Date: 06/22/2015
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kobayashi, Hidetomo
• Primary Examiner(s): Chow, Van N
• Application Number:
  US15/183,922
• Publication Number:
  US 20160370898A1
• Time in Patent Office: 1,041 Days
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• 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 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2310/0286 Details of a shift registers arranged for use in a driving circuit
• CPC Class Codes: G09G 2310/0291 Details of output amplifiers or buffers arranged for use in a driving circuit
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A source line through which a video signal is transmitted also serves as a driving electrode of a touch sensor. To perform display, a video signal is transmitted to the source line. To sense the touch, a driving signal is transmitted to the source line. A circuit for transmitting the video signal and the driving signal to the source line has a structure in which a period for transmitting the driving signal is added in the wiring through which the digital video signal is transmitted and the output to the source line is switched by using a switching circuit. Alternatively, the circuit has a structure in which a period for transmitting the driving signal is added in a wiring through which a latch signal is transmitted and the output to the source line is switched.

Claims

1. A semiconductor device comprising:

a first wiring;

a second wiring;

a first circuit; and

a second circuit,

wherein the first wiring has a function of transmitting a video signal to a pixel,

wherein the first circuit is electrically connected to the second wiring,

wherein the first circuit has a function of sensing a change in capacitance between the first wiring and the second wiring,

wherein the second circuit is electrically connected to the first wiring,

wherein the second circuit is capable of switching between a function of outputting the video signal and a function of outputting a driving signal for sensing the change in capacitance, and

wherein the first circuit is configured to sense an information by the first wiring and the second wiring.

2. The semiconductor device according to claim 1,

wherein the second circuit comprises a shift register, a first latch circuit, a second latch circuit, a D/A converter circuit, a switching circuit, and a buffer circuit,

wherein the first wiring comprises n wirings, n being a natural number of 2 or more,

wherein the first latch circuit is electrically connected to j×

p third wirings, j and p each being a natural number of 2 or more,

wherein the third wirings have a function of transmitting a p-bit digital signal and a function of transmitting the driving signal, the p-bit digital signal being the video signal,

wherein the first latch circuit has a function of holding the digital signal from the third wirings on a j column basis in accordance with pulse signals from n/j columns output from the shift register,

wherein the second latch circuit has a function of holding the digital signal held in the first latch circuit in accordance with a latch signal,

wherein the D/A converter circuit has a function of generating an analog video signal in accordance with the digital signal held in the second latch circuit,

wherein the switching circuit has a function of switching between transmission of the video signal to the buffer circuit and transmission of the driving signal to the buffer circuit,

wherein the buffer circuit has a function of amplifying the video signal or the driving signal and outputting the amplified video signal or the amplified driving signal to the first wiring, and

wherein the driving signal from any one of the third wirings is transmitted to the first wiring on a j column basis.

3. The semiconductor device according to claim 1,

wherein the second circuit comprises a shift register, a first latch circuit, a second latch circuit, a D/A converter circuit, a switching circuit, and a buffer circuit,

wherein the first wiring comprises n wirings, n being a natural number of 2 or more,

wherein the first latch circuit is electrically connected to a third wiring,

wherein the third wiring has a function of transmitting a digital signal, the digital signal being the video signal,

wherein the first latch circuit has a function of holding the digital signal from the third wiring in accordance with a pulse signal output from the shift register,

wherein the second latch circuit is electrically connected to h fourth wirings, h being a natural number of 2 or more,

wherein the fourth wirings have a function of transmitting a latch signal for enabling holding of the digital signal held in the first latch circuit and a function of transmitting the driving signal,

wherein the D/A converter circuit has a function of generating an analog video signal in accordance with the digital signal output from the second latch circuit,

wherein the buffer circuit has a function of amplifying the video signal or the driving signal and outputting the amplified video signal or the amplified driving signal to the first wiring, and

wherein the driving signal from any one of the fourth wirings is transmitted to the first wiring on a n/h column basis.

4. The semiconductor device according to claim 1,

wherein the pixel comprises a liquid crystal element, and

wherein the second wiring is electrically connected to a common electrode.

5. The semiconductor device according to claim 1,

wherein the first circuit and the second circuit are provided in one integrated circuit.

6. The semiconductor device according to claim 1,

wherein the pixel comprises a transistor, and

wherein the first wiring and the second wiring are provided on a substrate side where the transistor is formed.

7. A touch panel comprising:

the semiconductor device according to claim 1; and

a display portion.

8. An electronic device comprising:

the touch panel according to claim 7; and

a control portion.

15. The semiconductor device according to claim 1, wherein the information is whether touch is performed.

9. A semiconductor device comprising:

a first pixel;

a signal output circuit configured to output a video signal to the first pixel through a first wiring; and

a signal sensing circuit electrically connected to a second wiring,

wherein the signal sensing circuit is configured to sense whether touch is performed by the first wiring and the second wiring.

10. The semiconductor device according to claim 9, wherein the signal sensing circuit is configured to sense whether touch is performed by reading a change in capacitance between the first wiring and the second wiring.

11. The semiconductor device according to claim 9,

wherein the signal output circuit comprises a shift register and a switching circuit.

12. The semiconductor device according to claim 9, wherein the signal output circuit and the signal sensing circuit are included in one integrated circuit.

13. A touch panel comprising:

the semiconductor device according to claim 9; and

a display portion.

14. An electronic device comprising:

the touch panel according to claim 13; and

a control portion.