Display device, liquid crystal display device, electronic apparatus, and display device manufacturing method

• US 9,470,933 B2
• Filed: 01/16/2014
• Issued: 10/18/2016
• Est. Priority Date: 04/09/2008
• Status: Active Grant

• Current Assignee: Tianma Microelectronics Company Limited
• Original Assignee: NLT Technologies, Ltd.
• Inventors: Yanase, Jiro, Haga, Hiroshi
• Primary Examiner(s): Nguyen, Sang V
• Application Number:
  US14/157,089
• Publication Number:
  US 20140132859A1
• Time in Patent Office: 1,006 Days
• Field of Search: 349/148, 349/12, 345/174, 345/173
• US Class Current: 1/1
• CPC Class Codes: G02F 1/1343 Electrodes reflective electrodes G02F1/133553
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer

Abstract

To provide a low-cost display device which can accurately detect a position touched by a finger. A display device displays an image by having display elements capable of performing electro-optic responses formed between conductible first and second substrates, and detects a contact position touched by a contact body by having a conductive impedance surface formed on the second substrate side. The display device includes: linearization pattern sections formed on the first substrate, which include a plurality of electrodes capable of detecting electric currents on a conductive impedance surface; and a conductive member which electrically connects the linearization pattern sections with the conductive impedance surface on the second substrate.

Claims

1. A display device which displays an image, the display device comprising an electro-optic material between a thin film transistor substrate on which a thin film transistor is formed and a counter substrate, wherein

the counter substrate comprises a counter electrode of a first transparent conductive film,

a pixel area in which a plurality of pixel electrodes for supplying electric signals to the electro-optic material and a conducting film section near the pixel area are formed, together with the thin film transistor, on the thin film transistor substrate, the conducting film section comprising a second transparent conductive film that is disposed at an upper side of a metal layer, wherein a sheet resistance of the metal layer is lower than a sheet resistance of the second transparent conductive film,

a conductor is arranged in at least at a part of a peripheral area of the pixel area between the thin film transistor substrate and the counter substrate,

the conducting film section, the conductor, and the counter electrode of the first transparent conductive film to which electrostatic capacitance is formed due to a touch of a contact body are sequentially arranged from bottom to top in this order to be mutually connected electrically, and

the display device is configured to detect a contact position based on a change of the electrostatic capacitance of the counter electrode of the first transparent conductive film caused by the touch from the contact body and display an image on the counter electrode side of the first transparent conductive film.

2. The display device as claimed in claim 1, wherein the conductor is interposed between the thin film substrate and the counter substrate, and works as a sealing agent for sealing the electro-optic material.

3. The display device as claimed in claim 2, wherein the conductor is formed by being divided into a plurality of pieces.

4. The display device as claimed in claim 3, wherein the conductor is an anisotropic conductor.

5. The display device as claimed in claim 4, wherein the conductive film section comprises stacked layers of a plurality of conductive layers on the thin film transistor substrate.

6. The display device as claimed in claim 5, wherein the display device comprises a display drive period for displaying an image and a position detecting period for detecting a contact position regarding to drive the display device.

7. The display device as claimed in claim 6, further comprising a switching control device configured to perform switching controls such that the conducting film section is biased by a voltage source during the position detecting period.

8. The display device as claimed in claim 7, wherein the voltage source includes one of a common voltage potential (COM), a ground voltage potential (GND), or an alternating current (AC) voltage source.

9. The display device as claimed in claim 8, further comprising a detecting circuit configured to detect a current flown in the voltage source.

15. The display device as claimed in claim 4, further comprising a current detecting circuit configured to detect a current flown in the counter electrode via the anisotropic conductor and the conducting film section.

16. The display device as claimed in claim 15, further comprising an AC voltage source configured to apply AC voltage to the counter electrode via the anisotropic conductor and the conducting film section.

10. A display device which displays an image, the display device comprising an electro-optic material between a thin film transistor substrate on which a thin film transistor is formed and a counter substrate, wherein

the counter substrate comprises a counter electrode,

a pixel area in which a plurality of pixel electrodes for supplying electric signals to the elctro-optic material and a conducting film section near the pixel area are formed on the thin film transistor substrate,

a conductor is arranged in at least at a part of a peripheral area of the pixel area between the thin film transistor substrate and the counter substrate,

the conducting film section, the conductor, and the counter electrode are sequentially arranged from bottom to top in this order to be connected electrically,

the display device is configured to detect a contact position based on a change of an electrostatic capacitance caused by a contact from a contact body, and

the display device further comprises:

a voltage source configured to apply a voltage to the conducting film section,

a detecting circuit configured to detect a current flown in the voltage source, and

an impedance control device configured to control a first circuit part within the display area of the thin film transistor substrate to be in electrically higher impedance compared to that of a second circuit part that is outside the display area and control the first circuit part and the second circuit part to be in a non-conductive state, during the detecting period for detecting the contact position.

11. The display device as claimed in claim 10, wherein the impedance control device comprises:

a high-impedance switch part formed on wirings which connect the first circuit part with the second circuit part; and

a high-impedance control circuit which performs on/off controls of the high-impedance switch part.

12. A electronic apparatus comprising the display claimed in claim 11 loaded thereon.

13. A manufacturing method of a display device that displays an image, the display device configured to include an electro-optic material between a thin film transistor substrate on which a thin film transistor is formed and a counter substrate, the method comprising:

a first step of forming, together with the thin film transistor, a pixel area in which a plurality of pixel electrodes that supply electric signals to the electro-optic material are arranged, and simultaneously forming a conducting film section on the thin film transistor substrate, the conducting film section comprising a second transparent conductive film that is disposed at an upper side of a metal layer, wherein a sheet resistance of the metal layer is lower than a sheet resistance of the second transparent conductive film;

a second step of forming a counter electrode of a first transparent conductive film on the counter substrate;

a third step of arranging an anisotropic conductor in at least at a part of a peripheral area of the pixel area between the thin film transistor substrate and the counter substrate; and

a fourth step of sequentially arranging the conductive film section, the anisotropic conductor, and the counter electrode of the first transparent conductive film to which electrostatic capacitance is formed due to a touch of a contact body from bottom to top in this order to be mutually connected electrically.

14. The manufacturing method as claimed in claim 13, wherein the first step comprises photolithography or etching.