Electronic device, method for driving the electronic device, electro-optical device, and electronic equipment

• US 20040108518A1
• Filed: 03/17/2003
• Published: 06/10/2004
• Est. Priority Date: 03/29/2002
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Jo, Hiroaki
• Granted Patent: US 6,806,497 B2
• Time in Patent Office: Days
• US Class Current: 257/200
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/0295 by monitoring each display pixel
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 2330/12 Test circuits or failure detection circuits included in a display system, as permanent part thereof
• CPC Class Codes: G09G 3/006 Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3283 in which the data driver supplies a variable data current for setting the current through, or the voltage across, the light-emitting elements
• CPC Class Codes: G09G 3/3291 in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements

Abstract

[Object] To provide an electronic circuit, electronic device, method of driving the electronic circuit, electrooptical device, and electronic equipment for detecting operational characteristics of the electronic circuit at a high precision.

[Solving Means] A pixel circuit 20 includes a switching transistor Q13 connected between a driving transistor Q11 and organic EL element 21, and detecting transistor Q14 for supplying a current detecting circuit 19a with a driving current output by the driving transistor Q11. A holding capacitor C1 is supplied with test data voltage Vdata by turning on a switching transistor Q12 with the switching transistor Q13 turned off. The current detecting circuit 19a is supplied with a driving current from the driving transistor through the detecting transistor Q14 by turning on the detecting transistor Q14 with the switching transistor Q13 turned off. The current detecting circuit 19a thus detects the driving current in response to the test data voltage Vdata.

Claims

1. An electronic device comprising a plurality of unit circuits, wherein each of the unit circuits comprises:

a first transistor,

a holding element for holding an electrical signal, supplied through the first transistor, as an amount of electricity,

a second transistor, the conduction state of which is controlled in accordance with the amount of electricity held by the holding element,

a driven element which is supplied with an amount of current responsive to the conduction state, and

a third transistor which is connected in series with the second transistor,

wherein the electronic device is connected through the third transistor to a tester which detects the amount of current.

3. An electronic device according to one of claims 1 and 2, further comprising a fourth transistor connected between the driven element and the second transistor.

4. An electronic device according to one of claims 1 through 3, wherein the driven element is a current driven element.

5. An electronic device according to claim 3, wherein at least the fourth transistor remains in an off state for a duration throughout which the tester performs a current detecting operation.

6. An electronic device according to claim 1, wherein the third transistor is arranged in each of the unit circuits.

7. An electronic device according to one of claims 1 through 6, comprising a memory circuit which stores a correction value to an electrical signal fed through the first transistor and determined by the tester.

8. An electronic device according to one of claims 1 through 7, wherein the tester detects a current flowing through a current passage containing the second transistor and wherein the current passage excludes the driven element.

2. An electronic device comprising a plurality of unit circuits, wherein each of the unit circuits comprises:

a first transistor,

a holding element for holding an electrical signal, supplied through the first transistor, as an amount of electricity,

a second transistor, the conduction state of which is controlled in accordance with the amount of electricity held by the holding element, and

a driven element which is supplied with an amount of current responsive to the conduction state,

wherein the second transistor is connected in series with the first transistor, and

wherein the electronic device is connected through the first transistor to a tester which detects the amount of current.

9. A driving method for driving an electronic device comprising a first transistor, a holding element for holding an electrical signal, supplied through the first transistor, as an amount of electricity, a second transistor, the conduction state of which is controlled in accordance with the amount of electricity held by the holding element, a driven element which is supplied with an amount of current responsive to the conduction state, and a third transistor connected in series with the second transistor, the driving method comprising:

a first step of holding the amount of electricity based on the electrical signal by turning on the first transistor, and

a second step of detecting the amount of current flowing through a current passage containing the second transistor and the third transistor with the third transistor turned on to electrically connect the second transistor through the third transistor to a tester for detecting the amount of current.

10. A driving method for driving the electronic device according to claim 9, wherein the current passage excludes the driven element.

11. An electrooptical device containing a plurality of pixel circuits, each pixel circuit arranged at an intersection of each of a plurality of scanning lines and each of a plurality of data lines,

wherein the pixel circuit comprises:

a first transistor, the conduction of which is controlled by a scanning signal supplied through a corresponding scanning line of the plurality of scanning lines,

a holding element which holds, as an amount of electricity, a data signal supplied through a corresponding data line of the plurality of data lines and the first transistor,

a second transistor, the conduction state of which is controlled by the amount of electricity held by the holding element,

an electrooptical element supplied with an amount of current responsive to the conduction state, and

a third transistor connected in series with the second transistor,

wherein each of the plurality of pixel circuits is connected through the third transistor to a tester which detects the amount of current.

13. An electrooptical device according to claim 11, wherein the third transistor is connected to the tester through the corresponding data line of the plurality of data lines.

14. An electrooptical device according to one of claims 11 through 13, wherein the tester comprising:

a current detecting circuit for detecting the amount of current,

a correction value calculating circuit for determining a correction value to the electrical signal based on the amount of current detected by the current detecting circuit, and

a memory circuit for storing the correction value to the pixel circuit,

wherein the electrical signal is corrected by the correction value.

15. Electronic equipment incorporating an electrooptical device according to one of claims 11 through 14.

12. An electrooptical device containing a plurality of pixel circuits, each pixel circuit arranged at an intersection of each of a plurality of scanning lines and each of a plurality of data lines,

wherein the pixel circuit comprises:

a first transistor, the conduction of which is controlled by a scanning signal supplied through a corresponding scanning line of the plurality of scanning lines,

a holding element which holds, as an amount of electricity, a data signal supplied through a corresponding data line of the plurality of data lines and the first transistor,

a second transistor, the conduction state of which is controlled by the amount of electricity held by the holding element, the second transistor connected in series with the first transistor, and

an electrooptical element supplied with an amount of current responsive to the conduction state,

wherein each of the plurality of pixel circuits is connected through the first transistor to a tester which detects the amount of current.