Electronic apparatus, electronic system, and driving method for electronic apparatus

• US 7,310,092 B2
• Filed: 04/22/2003
• Issued: 12/18/2007
• Est. Priority Date: 04/24/2002
• Status: Expired due to Fees

• Current Assignee: EL Technology Fusion Godo Kaisha
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Imamura, Yoichi
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): Shapiro, Leonid
• Application Number:
  US10/419,807
• Publication Number:
  US 20040108998A1
• Time in Patent Office: 1,701 Days
• Field of Search: 345/204, 345/55, 345/76, 345/36, 345/60, 345/78, 345/82, 345/90, 345/92, 345/99, 345/103, 345/208
• US Class Current: 345/204
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0861 with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
• CPC Class Codes: G09G 2310/0248 Precharge or discharge of column electrodes before or after applying exact column voltages
• CPC Class Codes: G09G 2320/0223 Compensation for problems related to R-C delay and attenuation in electrodes of matrix panels, e.g. in gate electrodes or on-substrate video signal electrodes
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 3/325 the data current flowing through the driving transistor during a setting phase, e.g. by using a switch for connecting the driving transistor to the data driver
• 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

Abstract

An electronic apparatus includes unit circuits provided with electronic devices, data lines connected to the unit circuits, a first output device to output, as a first output, a current or a voltage corresponding to an externally supplied data signal, a second output device to output, as a second output, a current or a voltage corresponding to the magnitude of the first output, and a selection supply device to select one of or both the first output from the first output device and the second output from the second output device and to supply the selected output to the data line. With this configuration, the image reproducibility in a low-luminance/low-grayscale display area of a display apparatus using EL devices is enhanced.

Claims

1. An electronic apparatus, comprising:

unit circuits including electronic devices;

data lines connected to the corresponding unit circuits;

a constant-current output circuit provided with a pair of D/A converters including a first output device and a second output device, the first output device outputs, as a first output, a current or a voltage corresponding to a data signal, the second output device outputs, as a second output, a current or a voltage that is higher than the first output;

a current booster circuit, as a load device, causing a boost current to flow into the data lines in cooperation with the constant-current output circuit; and

a selection supply device to select one of or both the first output from the first output device and the second output from the second output device, and to supply the selected output to the data line.

2. The electronic apparatus according to claim 1, the selection supply device including at least one switching device.

3. The electronic apparatus according to claim 1, the ratio between a current driving capacity of the unit circuit and a current driving capacity of the current booster circuit being substantially equal to the ratio between a current output capacity of the first output device and a current output capacity of the second output device.

4. The electronic apparatus according to claim 1, the current booster circuit being disposed at a distal end of the data line when viewed from the second output device.

5. The electronic apparatus according to claim 1, the current booster circuit receiving a current flowing in the data line when the selection supply device selects the second current from the second output device, and outputting the selected second current to the data line.

6. The electronic apparatus according to claim 1, the select supply device selecting only the first output from the first output device, and supplying the first output to the data line at least during a predetermined last period portion of an output period for which an output is supplied to the electronic device.

7. The electronic apparatus according to claim 1, the selection supply device selecting at least the second output from the second output device at least during a predetermined first period portion of an output period for which an output is supplied to the electronic device.

8. The electronic apparatus according to claim 1, the selection supply device selecting at least the second output from the second output device, and supplying the selected output to the data line at least during a predetermined first period portion of an output period for which an output is supplied to the electronic device, and the selection supply device selecting at least the first output from the first output device, and supplying the selected output to the data line at least during a predetermined last period portion of the output period.

9. The electronic apparatus according to claim 1, the selection supply device being able to supply the output from the first output device and the output from the second output device at substantially the same portion of the data line.

10. The electronic apparatus according to claim 1, the second output device outputting, as the second output, a current or a voltage corresponding to an externally supplied data signal.

11. The electronic apparatus according to claim 1, further including a plurality of output supply devices including the first output device, the second output device, and the selection supply device for one of the data lines, and while one of the output supply devices stores a current value or a voltage value based on the data signal, at least the other one of the output supply devices supplies an output to the data line.

12. The electronic apparatus according to claim 11, the current supply device setting two adjacent horizontal scanning periods of a plurality of horizontal scanning periods to be a period to supply an output to the data line, and setting the remaining of the plurality of the horizontal scanning periods to be a period to control the unit circuit.

13. The electronic apparatus according to claim 12, a predetermined number of the electronic apparatuses forming one set, and each of the electronic apparatuses storing a current value or a voltage value based on the corresponding data signal in a corresponding one of sub-periods obtained by dividing the horizontal scanning period by a predetermined number.

14. The electronic apparatus according to claim 1,

a pair of the unit circuits being connected to one of the data lines, and one of a pair of control lines to control the output of each of the electronic devices being connected to the corresponding unit circuit, and the other control line being connected to the other unit circuit;

and

control signals having inverted phase portions, which are close or adjacent to each other, being supplied to the corresponding control lines.

15. The electronic apparatus according to claim 14, pulses having a predetermined duty ratio being continuously output to the control lines.

16. The electronic apparatus according to claim 14, the pair of control lines being crossed for the corresponding adjacent unit circuits.

17. The electronic apparatus according to claim 14,

a predetermined number of the unit circuits forming a set;

and

the control signals supplied to adjacent sets of the unit circuits having inverted phases, which are close or adjacent to each other, for the adjacent sets of the unit circuits.

18. The electronic apparatus according to claim 1, the electronic devices being current driving devices.

19. The electronic apparatus according to claim 1, the electronic devices being electro-optical devices.

20. An electronic system, comprising:

the electronic apparatus set forth in claim 1.