Image display unit with screen input function
View Patent ↗An image display unit with screen input function is provided, by which it is possible to input image data directly to a screen without decreasing numerical aperture of pixel. The image display unit comprises a light detecting TFT 61 receiving a light entering from a screen of a liquid crystal display panel, said light detecting TFT 61 is connected in series to a switching TFT 60 , which does not receive a light entering from the screen of the liquid crystal display panel. To a source electrode of the light detecting TFT 61 , a storage capacitor Cst and a pixel electrode of a liquid crystal element are connected. The liquid crystal element is represented by a capacitor C LC . A sensor control line 140 is connected to the gate electrode of the light detecting TFT 61 , and a gate line 120 is connected to the gate electrode of the switching TFT 60 . A data line 110 is connected to the drain electrode of the switching TFT 60 , and a storage line 150 is connected to one end of a storage capacitor Cst. An image signal is sent to a pixel electrode (ITO) of the liquid crystal element (C LC ). The light detecting TFT 61 transmits photoelectric current I sig generated by sensing the light to a sensor signal processing circuit (see FIG. 1 ) via the data line 110.
1. An image display unit with screen input function for inputting information by touching operation to a pixel area comprised of a plurality of pixels on a screen formed on a first insulating substrate, said image display unit comprising, for each of said plurality of pixels:
a first thin-film transistor shielded from projection of light coming from the direction of a pixel surface, and a second thin-film transistor connected in series with the first thin-film transistor and not shielded from projection of light coming from the direction of the pixel surface;
a gate electrode of said first thin-film transistor being connected to an associated gate line;
a gate electrode of said second thin-film transistor being connected to an associated sensor control line;
a drain electrode or a source electrode of said first thin-film transistor being connected to an associated data line; and
a storage capacitor having a first electrode connected to a source electrode or a drain electrode of said second thin-film transistor and to a first pixel electrode of said pixel,
wherein said second thin-film transistor is turned on by a sensing time selecting signal from said sensor control line during a period different from an image display period of said pixel, and photoelectric current generated by projection light sensing of said second thin-film transistor is accumulated as electric charge in said storage capacitor, and
wherein said accumulated electric charge is read out on said data line as light detecting current via said first thin-film transistor, and, after voltage conversion, said electric charge is provided as a detection signal of said touching operation.
2. The image display unit with screen input function according to claim 1 , wherein a second electrode of said storage capacitor is connected to a storage line.
3. The image display unit with screen input function according to claim 1 , further comprising a sensor signal processing circuit disposed outside said pixel area to generate a judging signal to judge whether said touching operation has occurred based on the detection signal of said touching operation.
4. The image display unit with screen input function according to claim 3 ,
wherein said judging signal is a bivalent signal, and
wherein said judging signal is sent to an upper control circuit of said image display unit to carry out an instruction based on coordinates of a touched site on the pixel area.
5. The image display unit with screen input function according to claim 1 , further comprising a changeover switch on the data line to change between a display signal and the detection signal of said touching operation.
6. The image display unit with screen input function according to claim 1 , wherein said sensor control line is commonly used by two of said pixels which are adjacent to each other in a direction of alignment of said gate line.
7. The image display unit with screen input function according to claim 1 , wherein said sensor control line for one pixel is also operative as a storage line for a different pixel.
8. The image display unit with screen input function according to claim 1 , wherein said period different from said image display period is a blanking period within a frame period.
9. The image display unit with screen input function according to claim 1 , further comprising a second insulating substrate attached to a main surface of said first insulating substrate, with a main surface thereof facing said main surface of said first insulating substrate,
wherein liquid crystal is sealed between said first insulating substrate and said second insulating substrate.
10. The image display unit with screen input function according to claim 9 , further comprising a counter electrode to generate an electric field on the main surface of said second insulating substrate between said first pixel electrode and said first insulating substrate,
wherein liquid crystal is sealed between said pixel electrode and said counter electrode.
11. The image display unit with screen input function according to claim 1 ,
wherein each said pixel includes a second pixel electrode, an organic EL light emitting layer being provided on an upper layer of the second pixel electrode, and
wherein the first pixel electrode is formed to cover said organic EL light emitting layer.
12. The image display unit with screen input function according to claim 11 , wherein said organic EL light emitting layer has different light emitting color portions for each of said plurality of pixels.
13. An image display unit with screen input function for inputting information by touching operation to a pixel area comprised of a plurality of pixels on a screen formed on a first insulating substrate, said image display unit comprising, for each of said plurality of pixels:
a first thin-film transistor shielded from projection of light coming from the direction of a pixel surface, and a second thin-film transistor connected in series with the first thin-film transistor and not shielded from projection of light coming from the direction of the pixel surface;
a gate electrode of said first thin-film transistor being connected to an associated gate line;
a gate electrode of said second thin-film transistor being connected to an associated sensor control line;
a drain electrode or a source electrode of said first thin-film transistor being connected to an associated data line;
a storage capacitor having a first electrode connected to a source electrode or a drain electrode of said second thin-film transistor and to a first pixel electrode of said pixel; and
an optical signal cumulative capacitor connected in parallel with said storage capacitor,
wherein said second thin-film transistor is turned on by a sensing time selecting signal from said sensor control line during a period different from an image display period of said pixel, and photoelectric current generated by projection light sensing of said second thin-film transistor is accumulated as electric charge in said storage capacitor,
wherein said accumulated electric charge is read out on said data line as light detecting current via said first thin-film transistor, and, after voltage conversion, said electric charge is provided as a detection signal of said touching operation, and
wherein a first electrode of said optical signal cumulative capacitor is connected between said first thin-film transistor and said second thin-film transistor, and a second electrode of said optical signal cumulative capacitor is connected to a storage line.