LIQUID CRYSTAL DISPLAY DEVICE WITH TOUCH PANEL

• US 20150091865A1
• Filed: 10/01/2014
• Published: 04/02/2015
• Est. Priority Date: 10/02/2013
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display Incorporated
• Inventors: FUNAYAMA, Yukihide
• Granted Patent: US 9,471,188 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• 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

Abstract

A liquid crystal display device with a touch panel includes: pixel electrodes which are disposed in each pixel disposed in a display region and to which a potential is applied depending on a gradation value; common electrodes which extend in one direction across the display region; detection electrodes which extend in a direction different from the one direction across the display region, form an electric capacitance with driving electrodes that are a part of the common electrodes , and detect a contact position on a panel; a liquid crystal layer that is formed by a liquid crystal composition in which an orientation is changed by an electric field formed by the pixel electrodes and the common electrodes; and a driving pulse output section that applies a driving pulse once to the driving electrodes for detecting contact within two successive horizontal synchronizing periods that are periods of display.

Claims

1. A liquid crystal display device with a touch panel comprising:

pixel electrodes that are a plurality of electrodes which are disposed in each pixel disposed in a display region and to which a potential is applied depending on a gradation value;

common electrodes that are a plurality of electrodes which extend in one direction across the display region;

detection electrodes that are a plurality of electrodes which extend in a direction different from the one direction across the display region, form an electric capacitance with driving electrodes that are a part of the common electrodes, and detect a contact position on a panel;

a liquid crystal layer that is formed by a liquid crystal composition in which an orientation is changed by an electric field formed by the pixel electrodes and the common electrodes; and

a driving pulse output section that applies a driving pulse once to the driving electrodes for detecting contact within two successive horizontal synchronizing periods that are periods of display.

2. The liquid crystal display device with a touch panel according to claim 1, further comprising:

a detection circuit that detects a touch by integrating a change in the potential of the detection electrodes on both of rising and falling of the driving pulse applied to the driving electrodes.

3. The liquid crystal display device with a touch panel according to claim 2,

wherein the detection circuit has a rising detection circuit that detects an electrical response in the detection electrodes on the rising of the driving pulse and a falling detection circuit that detects an electrical response in the detection electrodes on the falling of the driving pulse, and

wherein each of the rising detection circuit and the falling detection circuit has a comparator and a capacitance that is connected in parallel with the comparator.

4. The liquid crystal display device with a touch panel according to claim 1,

wherein the driving pulse output section generates the change in the potential of one of the rising and the falling of the driving pulse, after writing of the potential is completed with respect to the pixel electrodes depending on the gradation value.

5. The liquid crystal display device with a touch panel according to claim 1,

wherein the driving pulse output section generates the change in the potential of one of the rising and the falling of the driving pulse, before writing of a potential depending on the gradation value is completed with respect to the pixel electrodes while the potential depending on the gradation value is applied to the pixel electrodes.

6. The liquid crystal display device with a touch panel according to claim 1, further comprising:

a dummy electrode that detects noise;

a noise frequency detection section that detects a frequency of the noise detected by the dummy electrode; and

a frame frequency control section that sets a frame frequency based on the frequency detected by the noise frequency detection section.