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

• US 6,806,497 B2
• Filed: 03/17/2003
• Issued: 10/19/2004
• Est. Priority Date: 03/29/2002
• Status: Expired due to Term

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Jo, Hiroaki
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): HO, TU TU V
• Application Number:
  US10/388,810
• Publication Number:
  US 20040108518A1
• Time in Patent Office: 582 Days
• Field of Search: 257/59, 257/72, 345/212
• US Class Current: 257/59
• 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

The invention provides an electronic circuit, electronic device, method of driving the electronic circuit, electro-optical device, and electronic equipment to detect operational characteristics of the electronic circuit at a high precision. A pixel circuit includes a switching transistor connected between a driving transistor and organic EL element, and detecting transistor for supplying a current detecting circuit with a driving current output by the driving transistor. A holding capacitor is supplied with test data voltage Vdata by turning on a switching transistor with the switching transistor turned off. The current detecting circuit is supplied with a driving current from the driving transistor through the detecting transistor by turning on the detecting transistor with the switching transistor turned off. The current detecting circuit thus detects the driving current in response to the test voltage Vdata.

Claims

1. An electronic device usable with a tester, comprising:

a plurality of unit circuits, each of the unit circuits including;

a first transistor;

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

a second transistor having a conduction state that 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,

the electronic device being connectable through the third transistor to the tester which detects the amount of current.

3. The electronic device according to claim 1, further comprising a fourth transistor connected between the driven element and the second transistor.

4. The electronic device according to claim 1, the driven element being a current driven element.

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

6. The electronic device according to claim 1, the third transistor being arranged in each of the unit circuits.

7. The electronic device according to claim 1, further comprising a memory circuit which stores a correction value to an electrical signal fed through the first transistor and determined by the tester.

8. The electronic device according to claim 1, the tester detecting a current flowing through a current passage containing the second transistor, and the current passage excluding the driven element.

2. An electronic device usable with a tester, comprising:

a plurality of unit circuits, each of the unit circuits including;

a first transistors;

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

a second transistor having a conduction state that 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;

the second transistor being connected in series with the first transistor; and

the electronic device being connectable through the first transistor to the tester which detects the amount of current.

9. A driving method of driving an electronic device that includes a first transistor, a holding element to hold 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:

holding the amount of electricity based on the electrical signal by turning on the first transistor; and

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 to detect the amount of current.

10. The driving method for driving the electronic device according to claim 9, the current passage excluding the driven element.

11. An electro-optical device for use with a tester, comprising

a plurality of scanning lines;

a plurality of data lines; and

a plurality of pixel circuits, each pixel circuit being arranged at an intersection of each of the plurality of scanning lines and each of the plurality of data lines, each

pixel circuit including;

a first transistor having a conduction that 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 having a conduction state that is controlled by the amount of electricity held by the holding element,

an electro-optical element supplied with an amount of current responsive to the conduction state; and

a third transistor connected in series with the second transistor,

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

13. The electro-optical device according to claim 11, the third transistor being connected to the tester through the corresponding data line of the plurality of data lines.

14. The electro-optical device according to claims 11, the tester including:

a current detecting circuit to detect the amount of current,

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

a memory circuit to store the correction value to the pixel circuit,

the electrical signal being corrected by the correction value.

15. Electronic equipment, comprising:

the electro-optical device according to claim 11.

12. An electro-optical device for use with a tester comprising:

a plurality of scanning lines;

a plurality of data lines; and

a plurality of pixel circuits, each pixel circuit being arranged at an intersection of each of the plurality of scanning lines and each of the plurality of data lines,

the pixel circuit including;

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

an electro-optical element supplied with an amount of current responsive to the conduction state;

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