Self-luminescent display device having a temperature and light sensor for correcting image data and electronic apparatus thereof

• US 8,508,441 B2
• Filed: 04/02/2010
• Issued: 08/13/2013
• Est. Priority Date: 04/17/2009
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Kimura, Fusashi, Tsuda, Atsunari
• Primary Examiner(s): Nguyen, Chanh
• Assistant Examiner(s): Pham, Long D
• Application Number:
  US12/753,193
• Publication Number:
  US 20100265228A1
• Time in Patent Office: 1,229 Days
• Field of Search: 345/77, 345/81
• US Class Current: 345/77
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/029 by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

A self-luminescent display device includes a pixel unit in which a plurality of pixels including a self-luminescent pixel is arranged, an external light sensor which measures an external light intensity, a temperature sensor which measures an environmental temperature, an image correcting unit which corrects image data input to the image correcting unit on the basis of statistical data of the image data, a light adjusting unit which produces a light adjusting signal on the basis of a measurement signal of the external light sensor, a temperature control unit which produces a temperature correcting signal on the basis of a measurement signal of the temperature sensor, and a display control unit which produces a brightness correcting signal for correcting light emitting brightness of the pixels in the pixel unit on the basis of the light adjusting signal and the temperature correcting signal. The light emitting brightness of the pixels in the pixel unit is adjusted on the basis of the image data corrected by the image correcting unit and the brightness correcting signal.

Claims

1. A self-luminescent display device comprising:

a pixel unit in which a plurality of pixels including a self-luminescent pixel is arranged;

an external light sensor which measures an external light intensity;

a temperature sensor which measures an external environmental temperature;

an image correcting unit which corrects image data input to the image correcting unit on the basis of statistical data of the image data;

a light adjusting unit which produces a light adjusting signal on the basis of a measurement signal produced from the external light intensity by the external light sensor;

a temperature control unit which produces a temperature correcting signal on the basis of a measurement signal produced from the external environmental temperature by the temperature sensor;

an adjusting unit which changes, upon a duty ratio of a brightness correcting signal being as a pulse width modulation (PWM) signal is less than a certain duty ratio, the duty ratio of the brightness correcting signal being as the PWM signal to a value more than the certain duty ratio, the adjusting unit providing the image correcting unit with a brightness adjusting signal for compensating for an increase of the light emitting brightness of the pixels caused by the change of the duty ratio; and

a display control unit which produces a brightness correcting signal for controlling light emitting brightness of the pixels in the pixel unit on the basis of the light adjusting signal and the temperature correcting signal, wherein

the light emitting brightness of the pixels in the pixel unit is adjusted on the basis of the image data corrected by the image correcting unit and the brightness correcting, signal,

each of the pixels has a self-luminescent element, a driving transistor which provides the self-luminescent element with a driving current, and a light emitting control transistor which controls a period of time for which the self-luminescent element emits light,

the image correcting unit makes a brightness histogram of the input image data, the image correcting unit analyzing the brightness histogram, the image correcting unit correcting the image data provided to the pixels upon a brightness value of a whole image being more than a certain threshold so that brightness of the whole image decreases, and

the display control unit produces the brightness correcting signal as the PWM signal of a variable duty ratio on the basis of the external light intensity and the environmental temperature, the display control unit controlling an on/off state of the light emitting control transistor in the pixel by means of the brightness correcting signal as the PWM signal of the variable duty ratio.

2. The self-luminescent display device according to claim 1, wherein:

the self-luminescent element is an organic EL element.

3. An electronic apparatus comprising the self-luminescent display device according to claim 1.