Display apparatus, source driver and dispaly panel

• US 7,864,171 B2
• Filed: 10/30/2007
• Issued: 01/04/2011
• Est. Priority Date: 04/09/2003
• Status: Expired due to Fees

• Current Assignee: Collabo Innovations, Inc. (Wi-LAN Inc.)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Oomori, Tetsurou, Date, Yoshito
• Primary Examiner(s): TRAN, MY CHAU T
• Application Number:
  US11/976,953
• Publication Number:
  US 20080084411A1
• Time in Patent Office: 1,162 Days
• Field of Search: 345/76, 345/77, 345/82, 345/83, 345/84, 345/87, 345/88, 345/98, 345/99, 345/204, 345/690, 345/211, 345/212
• US Class Current: 345/212
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/0248 Precharge or discharge of column electrodes before or after applying exact column voltages
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• 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 3/3241 the current through the light-emitting element being set using a data current provided by the data driver, e.g. by using a two-transistor current mirror
• 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
• 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

An organic EL display apparatus includes: a display panel on which a plurality of pixel sections are provided; source drivers provided with pixel drivers, which includes current drivers for supplying drive currents to the pixel sections, registers for latching data signals and timing control units; signal lines for supplying the drive currents from the current drivers to the pixel sections. Each of the current drivers is controlled by the associated timing control unit to allow a current larger than or equal to a current which is set in accordance with the data signal to flow only during a given period in a current setting mode, so that the value of a current flowing in the pixel section reaches a target value in a short time.

Claims

1. A display apparatus, comprising:

a display panel provided with a pixel section including a light-emitting device driven by a current and with a signal line connected to the pixel section; and

a source driver for supplying a drive current to the pixel section via the signal line,

wherein the source driver includes;

a register for latching display data having N bits and for outputting the display data;

a current driver for outputting the drive current according to the display data input from the register;

voltage supplying means having an output impedance lower than that of the current driver;

a line for connecting the signal line and the voltage supplying means to each other;

a timing control unit for outputting a control signal; and

a short-circuit switch provided on the line and used for electrically connecting the signal line and the voltage supplying means to each other only during a given period in a current setting mode in accordance with the control signal.

2. The display apparatus of claim 1, wherein the voltage supplying means includes:

a dummy circuit including;

a dummy pixel section which is provided on the display panel, includes a TFT and a capacitance and is not used for a display;

a dummy signal line provided on the display panel and used for supplying a current to the dummy pixel section; and

a dummy pixel driver provided in the source driver, connected to the dummy signal line and including a dummy current driver for outputting a constant current during operation; and

a current amplifying buffer connected to the dummy current driver and used for outputting an output voltage of the dummy current driver to the signal line.

3. The display apparatus of claim 1, wherein the current driver is plural in number, and

the voltage supplying means is singular in number with respect to the plurality of current drivers.

4. The display apparatus of claim 1, wherein the voltage supplying means is a voltage-output D/A converter provided in a one-to-one correspondence with the current driver and capable of changing an output voltage of the D/A converter in accordance with the display data output from the register.

5. The display apparatus of claim 4, wherein the voltage-output D/A converter changes the output voltage of the D/A converter in accordance with the one or two most significant bits of the display data.

6. The display apparatus of claim 1, wherein the voltage supplying means is a line connected to an external power supply.

7. A source driver, comprising:

a register for latching display data having N bits and for outputting the display data;

a current driver having an output terminal for outputting the drive current according to the display data input from the register;

voltage supplying means having an output impedance lower than that of the current driver;

a line for connecting the output terminal of the current driver and the voltage supplying means;

a timing control unit for outputting a control signal; and

a short-circuit switch provided on the line and used for electrically connecting the line and the voltage supplying means to each other only during a given period in a current setting mode in accordance with the control signal.