Display device

• US 9,626,037 B2
• Filed: 06/17/2015
• Issued: 04/18/2017
• Est. Priority Date: 06/30/2009
• Status: Expired due to Fees

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display Incorporated
• Inventors: Ishizaki, Koji, Noguchi, Kouji, Nakanishi, Takayuki, Teranishi, Yasuyuki, Takeuchi, Takeya
• Primary Examiner(s): Haley, Joseph
• Assistant Examiner(s): Iluyomade, Ifedayo
• Application Number:
  US14/741,620
• Publication Number:
  US 20150286337A1
• Time in Patent Office: 671 Days
• Field of Search: None
• 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 2203/04112 Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
• CPC Class Codes: G06F 2218/04 Denoising
• 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 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact
• CPC Class Codes: G09G 2310/0248 Precharge or discharge of column electrodes before or after applying exact column voltages
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2310/0262 The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data electrodes
• CPC Class Codes: G09G 2320/0204 Compensation of DC component across the pixels in flat panels
• CPC Class Codes: G09G 2320/0209 Crosstalk reduction, i.e. to reduce direct or indirect influences of signals directed to a certain pixel of the displayed image on other pixels of said image, inclusive of influences affecting pixels in different frames or fields or sub-images which constitute a same image, e.g. left and right images of a stereoscopic display
• CPC Class Codes: G09G 2320/0219 Reducing feedthrough effects in active matrix panels, i.e. voltage changes on the scan electrode influencing the pixel voltage due to capacitive coupling
• CPC Class Codes: G09G 2320/029 by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
• CPC Class Codes: G09G 3/36 using liquid crystals
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3655 Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors
• CPC Class Codes: G09G 3/3659 the addressing of the pixel involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependant on signal of two data electrodes
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers

Abstract

A display device includes: a display functional layer that can change display for each pixel in accordance with an application voltage; a plurality of driving electrodes separately disposed in one direction; a plurality of pixel signal lines to which pixel signals used for applying the application voltage to the display functional layer in accordance with an electric potential difference from the display reference electric potential are applied; a plurality of detection electrodes that are separately disposed in a direction other than the one direction, are coupled with the driving electrodes as electrostatic capacitance, generate detection electric potentials in response to the detection driving signal, and change the detection electric potential in accordance with approach of a detection target object; and a pixel signal control unit that controls the pixel signals so as to include pixel signals having different polarities during the display period.

Claims

1. A display device comprising:

a display functional layer that can change display for each pixel in accordance with an application voltage;

a plurality of driving electrodes, disposed in a first direction so as to be separated from one another, to which a display reference electric potential maintained at a constant level is applied during a display period in which display is performed in a pixel arrangement along the first direction and to which a detection driving signal is applied when detection scanning is performed by changing the display reference electric potential to another electric potential;

a plurality of pixel signal lines to which pixel signals used for applying the application voltage to the display functional layer in accordance with an electric potential difference from the display reference electric potential are applied;

a plurality of detection electrodes that are disposed so as to be separated from one another in a direction other than the first direction, are coupled with the plurality of the driving electrodes as electrostatic capacitance, generate detection electric potentials in response to the detection driving signal that is applied to at least one driving electrode; and

a pixel signal control unit that controls the plurality of pixel signals applied to the plurality of pixel signal lines so that pixel signals in one display period have at least one pulse whose polarity is inverted and that the pixel signals before being inverted and the pixel signals after being inverted have the same electric potential differences as the display reference electric potential.

2. The display device according to claim 1,

wherein the inside of one pixel is divided into two areas, and a pixel electrode and a switching device are disposed in the areas, and

wherein the pixel signal control unit controls polarity control and supply timings of the pixel signals and opening or closing of the switching device such that the same pixel signal is supplied from one pixel signal line to the two areas inside the same pixel with opposite polarities.

3. The display device according to claim 1,

wherein the inside of one pixel is divided into two areas, and each of the areas is configured so as to be able to maintain different pixel signals, and

wherein the pixel signal control unit controls polarity control of the pixel signals and discharge timings for two different pixel signal lines adjacent to each other such that the same pixel signal is supplied from the two different pixel signal lines to the two areas inside the same pixel with opposite polarities.

4. The display device according to claim 1, wherein the pixel signal control unit controls the pixel signals having opposite polarities so as to be simultaneously discharged to a plurality of pixel signal lines when an operation of supplying the pixel signal to one pixel electrode inside one pixel through a switching device is performed for a plurality of pixels in a parallel manner.

5. The display device according to claim 1, wherein the pixel signal control unit controls the number of the pixel signals having the positive polarity with respect to a center electric potential to be the same as the number of the pixel signals having the negative polarity with respect to the center electric potential within the fixed display period.

6. The display device according to claim 1, wherein the pixel signal control unit controls the polarities of the pixel signals of adjacent pixels so as to be inverted within the fixed display period.

7. The display device according to claim 6, wherein the pixel signal control unit controls the polarities of the pixel signals that are adjacent to each other in a row direction and a column direction so as to be inverted between the fixed display period and another fixed display period next thereto.

8. The display device according to claim 7, wherein the pixel signal control unit controls dot-inversion driving in which the polarity of the pixel signal of the same pixel is inverted between a display period of one screen and a display period of another screen next thereto.

9. The display device according to claim 1, wherein the display functional layer is a liquid crystal layer.

10. The display device according to claim 1,

wherein the plurality of detection electrodes are disposed on a display surface side of the display functional layer,

wherein the plurality of driving electrodes are disposed on a side of the display functional layer that is opposite to the display surface, and

wherein a plurality of pixel electrodes, separated for each pixel, that apply the application voltage to the display functional layer with respect to an electric potential of a corresponding driving electrode used as a reference for each pixel when the pixel signal is supplied are disposed between the display functional layer and the plurality of driving electrodes.

11. The display device according to claim 1, wherein the number of the inverted pulses is equal to the number of not-inverted pulses.

12. The display device according to claim 1, wherein the pixel signal control unit is configured to control the plurality of pixel signals applied to the plurality of pixel signal lines so that pixel signals in 1 H display period have at least one pulse whose polarity is inverted with respect to the display reference electric potential from another pulse in the 1 H display period, while the display reference electric potential is maintained at the constant level in the 1 H display period.

13. The display device according to claim 12, wherein the detection scanning is performed in a period that is different from the 1 H display period.

14. The display device according to claim 1, wherein two pulses of pixel signals, which include a pixel signal before being inverted and a pixel signal after being inverted, are simultaneously applied to a same pixel signal line.