US 7,924,248 B2 · Drive method of EL display apparatus

Abstract

To provide a drive method capable of maintaining gradation display performance regardless of screen display brightness. Reference numeral 491R denotes a regulator used to control reference current for red (R). By adjusting a reference current for R linearly, it is possible to linearly vary a current flowing through a transistor 472a which constitutes a current mirror with a transistor 471R. This changes a current flowing through a transistor 472b which has received a current-based delivery from the transistor 472a in a transistor group 521a. This in turn causes changes to a transistor 473a in a transistor group 521b which constitutes a current mirror with the transistor 472b, resulting in changes to a transistor 473b which has received a current-based delivery from the transistor 473a. Thus, since drive current of the unit transistor 484 changes, programming current can be changed linearly. Reference numeral 491G denotes a regulator used to control reference current for green (G) and reference numeral 491B denotes a regulator used to control reference current for blue (B). By adjusting 491R, 491G, and 491B, it is possible to adjust white balance easily and change screen brightness easily. Besides, gradation display performance is maintained at any screen brightness.

Claims20

Dependent claims

A drive method of an EL display apparatus that comprises a display screen in which a plurality of pixels each of which includes an EL element are formed in a matrix, the drive method comprising:

weighting a video signal with respect to a color of respective of the plurality of pixels, said video signal generating a signal which is to be impressed to the respective pixels of the EL display apparatus,
aggregating said weighted video signal, and
setting a maximum value of current that flows in the EL element of said pixel or a maximum value of emission brightness of the EL element of said pixel to a greater value according as a result of said aggregating of said weighted video signal gets smaller than a predetermined value.

A drive method of an EL display apparatus that comprises a display screen in which a plurality of pixels each of which includes an EL element are formed in a matrix, the drive method comprising:

obtaining a value of current flowing in said display screen based on video data which is input in said EL display apparatus, wherein a value of current obtained in a first frame period is defined as a first value of current and a value of current obtained in a frame period other than said first frame period is defined as a second value of current,
setting a maximum value of current that flows in the EL element of said pixel or a maximum value of emission brightness of the EL element of said pixel when said obtained value of current is said first value of current more greatly than a maximum value of current that flows in the EL element of said pixel or a maximum value of emission brightness of the EL element of said pixel when said obtained value of current is said second value of current, in case that said first value of current is smaller than a predetermined value and is smaller than said second value of current.

A drive method of an EL display apparatus that comprises a display screen in which a plurality of pixels each of which includes an EL element and a driver transistor for supplying current to said EL element are formed in a matrix, wherein a multiplier of a gamma curve which converts input gradation data Di into output gradation data Do is defined as x,

the drive method comprising:
obtaining a value of aggregating video data based on video signal input to said EL display apparatus, wherein each of said aggregated values is defined as A and B respectively;
setting x of the multiplier of a gamma curve when said aggregated value is said B more greatly than x of the multiplier of a gamma curve when said aggregated value is said A, in case that said aggregated value B is greater than said aggregated value A;
and
wherein when said aggregated value is said A, a current which is to flow in a first EL element corresponding to a first input gradation data D1 is defined as IA, and when said aggregated value is said B, a current which is to flow in said first EL element corresponding to said first input gradation data D1 is defined as IB,
setting said IA more greatly than said IB.

3 more elements

Dependencies are inferred from the claim text.

Drive method of EL display apparatus

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Drive method of EL display apparatus

Life of this patent

Abstract

Claims20