Display apparatus that controls luminance irregularity and gradation irregularity, and method for controlling said display apparatus

• US 20050212787A1
• Filed: 03/21/2005
• Published: 09/29/2005
• Est. Priority Date: 03/24/2004
• Status: Abandoned Application

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Matsumoto, Shoichiro, Yamada, Kouiti, Noguchi, Yukihiro, Sekine, Satoru
• Application Number:
  US11/084,134
• Publication Number:
  US 20050212787A1
• Time in Patent Office: Days
• US Class Current: 345/204
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0852 being a dynamic memory with more than 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 2310/0218 with collection of electrodes in groups for n-dimensional addressing
• CPC Class Codes: G09G 2310/066 Waveforms comprising a gently increasing or decreasing portion, e.g. ramp
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• 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

In an active matrix display apparatus, the drive transistor to drive an OLED self-corrects the operation timing of the drive transistor. A correction transistor controls on and off of the self-correction. The drive circuit self-corrects the operation of the drive transistor by generating a luminance signal which is corrected based on a predetermined signal delivered temporarily and an operation threshold value. The current flowing to the OLED is controlled by gradually changing the voltage of luminance signal from a ramp signal line. After the luminance signal for one frame is inputted to each pixel, the same luminance signal for one frame is inputted to the each pixel in a reversed scanning direction. One frame period is divided into a plurality of subframe periods and the data control circuit inputs respectively the same luminance signal to each pixel in the plurality of subframe periods.

Claims

1. A display apparatus including a plurality of pixels arranged in a matrix, each of the plurality of pixels including:

an optical element of current-driven type;

a drive circuit of non-complementing type which drives said optical element based on a luminance signal and self-corrects a drive operation thereof;

a correction circuit which controls on and off of the self-correction of said drive circuit; and

a holding circuit which holds the luminance signal used in the drive operation,

wherein said drive circuit generates a luminance signal which is corrected based on a predetermined signal delivered temporarily and an operation threshold value of said drive circuit, and self-corrects the drive operation by driving said optical element based on the corrected luminance signal.

2. A display apparatus according to claim 1, each of the plurality of pixels further including a control circuit which controls drive of said optical element by said drive circuit, by gradually changing voltage of the luminance signal held in said holding circuit,

wherein said drive circuit self-corrects operation timing of said drive circuit.

3. A display apparatus according to claim 1, wherein said drive circuit performs self-correction by using an uncorrected luminance signal delivered temporarily as a predetermined signal.

4. A display apparatus according to claim 1, each of the plurality of pixels further including a power supply circuit which shuts off said drive circuit from a power supply line during a period at which the self-correction is being performed.

5. A display apparatus including a plurality of pixels arranged in a matrix, each of the plurality of pixels including:

an optical element of current-driven type;

a drive circuit which drives said optical element based on a luminance signal and self-corrects a drive operation thereof;

a power supply circuit, connected with said drive circuit, which controls power supply to said optical element via said drive circuit;

a write circuit, connected with said drive circuit, which controls input of the luminance signal to the pixel;

a correction circuit which connects and shuts off a path through which a signal that has flowed to said drive circuit is inputted to said drive circuit for performing self-correction;

a holding capacitance which holds a signal inputted to said drive circuit;

a control circuit which controls drive of said optical element by said drive circuit, by gradually changing voltage of the signal held by said holding capacitance; and

a reset circuit which connects and shuts off a path of drive current to said optical element,

wherein said drive circuit generates a luminance signal which is corrected based on a luminance signal delivered temporarily through said write circuit and an operation threshold value of said drive circuit, and self-corrects the drive operation by driving said optical element based on the thus corrected luminance signal,

wherein said power supply circuit shuts off power to said optical element via said drive circuit during a period at which the self-correction is being performed, and

wherein said reset circuit shuts off the path of drive current to said optical element during a period at which the self-correction is being performed.

6. A display apparatus controlling method, comprising:

delivering a predetermined signal to a drive circuit of non-complementing type which drives an optical element of current-driven type;

generating a luminance signal by correcting the predetermined signal flowing through the drive circuit with an operation threshold value of the drive circuit;

setting the corrected luminance signal in the drive circuit and holding the thus set corrected luminance signal;

shutting off flow of the predetermined signal to the drive circuit; and

supplying drive current to the optical element by gradually changing voltage of the luminance signal held in said setting and holding.

7. A display apparatus of active matrix type, including:

a plurality of pixels arranged in a matrix; and

a data control circuit which inputs a luminance signal to each of the plurality of pixels so that one frame is displayed a plurality of times in different scanning directions.

10. A display apparatus according to claim 7, wherein said data control circuit inputs an equal luminance signal to each pixel respectively in a plurality of subframe periods which are obtained by dividing one frame period.

8. A display apparatus of active matrix type, comprising:

a plurality of pixels arranged in a matrix;

a selection control circuit which selects a pixel line to which a luminance signal is to be inputted among the plurality of pixels; and

a data control circuit which sequentially inputs the luminance signal for each pixel contained in the pixel line selected by said selection control circuit,

wherein said data control circuit is such that after a luminance signal for one frame is inputted to each pixel, the same luminance signal for one frame is again inputted to the each pixel in a reversed scanning direction, in order for the luminance signal for one frame to be inputted a plurality of times for the each pixel.

11. A display apparatus according to claim 8, wherein said data control circuit reverses the scanning direction for the each pixel line selected.

9. A display apparatus, including:

a plurality of pixels arranged in a matrix;

a selection control circuit which selects a pixel line to which a luminance signal is to be inputted among the plurality of pixels; and

a data control circuit which sequentially inputs the luminance signal for each pixel contained in the pixel line selected by said selection control circuit,

each of the plurality of pixels including;

an optical element of current-driven type;

a drive circuit which drives the optical element based on a luminance signal which has been corrected according to an operating characteristic; and

a write circuit which controls write of the luminance signal,

wherein said data control circuit is such that after a luminance signal for one frame is inputted to each pixel, the same luminance signal for one frame is again inputted to the each pixel in a reversed scanning direction, in order for the luminance signal for one frame to be inputted a plurality of times for the each pixel.

12. A display apparatus controlling method, including:

first selecting sequentially a pixel line, to which a luminance signal is to be inputted, among a plurality of pixels arranged in a matrix;

inputting sequentially a luminance signal of one frame in a predetermined scanning direction for each pixel contained in the pixel line selected by said first selecting, every time the pixel line is selected in the first selecting;

correcting the inputted luminance signal based on an operating characteristic of a drive circuit included in the pixel;

second selecting sequentially the pixel line from the beginning, after completing said first selecting for all pixel lines contained in the plurality of pixels;

inputting sequentially the same luminance signal as said luminance signal of one frame in a scanning direction opposite to the predetermined scanning direction for each pixel contained in the pixel line selected by said second selecting, every time the pixel line is selected in the second selecting; and

correcting the inputted luminance signal based on an operating characteristic of a drive circuit included in the pixel.

13. A display apparatus using a time gradation system, the apparatus comprising:

an optical element of current-driven type;

a drive circuit which drives said optical element; and

a time control circuit which controls drive timing by said drive circuit according to a luminance signal inputted,

wherein said time control circuit controls emission start timing according to the luminance signal in a control of a first emission period which is any emission period among a plurality of emission periods for one luminance signal, and controls emission stop timing according to the luminance signal in a control of a second emission period which is any emission period different from the first emission period thereamong.

14. A display apparatus according to claim 13, wherein a difference caused in the emission start timing according to the luminance signal in the control of a first emission period and based on variation in an operation threshold of said time control circuit is cancelled by a difference caused in the emission stop timing according to the luminance signal in the control of a second emission period and based on variation in an operation threshold of said time control circuit.

15. A display apparatus according to claim 13, further comprising a drive control circuit which turns said drive circuit on in the first emission period when said time control circuit is turned on and which turns said drive circuit off in the second emission period when said time control circuit is turned on.

16. A display apparatus according to claim 13, wherein said time control circuit controls, in the control of the first emission period, the emission start timing by said drive circuit, by gradually changing voltage of a luminance signal indicative of the emission start timing whereas said time control circuit controls, in the control of the second emission period, the emission stop timing by said drive circuit, by gradually changing voltage of a luminance signal indicative of the emission stop timing.

17. A display apparatus according to claim 13, wherein said time control circuit is structured by a transistor and wherein said time control circuit controls, in the control of the first emission period, the emission start timing by said drive circuit, by gradually changing one of source voltage and drain voltage of the transistor whereas said time control circuit controls, in the control of the second emission period, the emission stop timing by said drive circuit, by gradually changing one of source voltage and drain voltage of the transistor.

18. A display apparatus, comprising:

a time control transistor which controls drive timing of an optical element according to a luminance signal inputted; and

a circuit which gradually changes one of source voltage and drain voltage of said time control transistor,

wherein said time control transistor controls emission start timing of the optical element in a control of a first emission period which is any emission period among a plurality of emission periods for one luminance signal, by gradually changing one of the source voltage and drain voltage thereof whereas said time control transistor controls emission stop timing of the optical element in a control of a second emission period which is any emission period different from the first emission period thereamong, by gradually changing one of the source voltage and drain voltage thereof.

19. A display apparatus controlling method, including:

inputting a luminance signal indicative of emission start timing of an optical element in a control of a first emission period which is any emission period among a plurality of emission periods for one luminance signal;

changing gradually voltage of the luminance signal indicative of the emission start timing;

turning a drive circuit on and starting emission of the optical element when a time control circuit which controls drive timing by the drive circuit is turned on by said changing gradually voltage of the luminance signal;

stopping the emission of the optical element with a predetermined timing;

inputting a luminance signal indicative of emission stop timing of the optical element in a control of a second emission period which is any emission period different from the first emission period among the plurality of emission periods;

starting emission of the optical element with a predetermined timing;

changing gradually voltage of the luminance signal indicative of the emission stop timing; and

turning the drive circuit off and stopping the emission of the optical element when the time control circuit is turned on by said changing gradually voltage of the luminance signal.