The application claims priority to Korean Patent Application No. 10-2020-0064181, filed May 28, 2020, and all the benefits accruing therefrom under 35 U.S.C. § 119, the content of which in its entirety is herein incorporated by reference.

BACKGROUND

1. Field

Embodiments of the invention relate to a display device and a driving method thereof.

2. Description of the Related Art

With the development of information technology, display devices, which are a connection medium between users and information, have been widely used. Such display devices may include a liquid crystal display device, an organic light emitting display device, a plasma display device, and the like.

A display device may include a plurality of pixels and display an image (frame) through a combination of light emitted from the pixels. When a plurality of different images are continuously displayed, a user may recognize the images as a moving image. In addition, when a plurality of identical images are continuously displayed, the user may recognize the images as a still image.

SUMMARY

In a display device, when a still image is displayed for a long time or when a part of a moving image such as a logo is displayed for a long time with a same luminance, pixel deterioration and afterimages may occur. Accordingly, in a display device, grayscales of the logo may be corrected to prevent the afterimages. However, it may be difficult to accurately specify pixels corresponding to the logo.

Embodiments are directed to a display device and a driving method thereof for effectively preventing afterimages by accurately specifying pixels corresponding to a logo.

An embodiment of a display device according to the invention includes: pixels; an image converter which generates a second image by correcting grayscales of a logo among a first image for the pixels; and a data driver which provides data voltages corresponding to the second image to the pixels. In such an embodiment, the image converter generates first accumulated data by accumulating first map data corresponding to a logo area larger than the logo among the first image during a plurality of frame periods, generates second accumulated data by scaling the first accumulated data every refresh cycle, generates third accumulated data by initializing values smaller than a first threshold value among the second accumulated data to be a background value, and specifies pixels corresponding to the logo based on second map data corresponding to the third accumulated data.

In an embodiment, the image converter may include a logo detector which detects the logo area among the first image, and the logo detector may generate the first map data in which pixels identified as the logo among the logo area are indicated as a first binary level and pixels identified as a background among the logo area are indicated as a second binary level.

In an embodiment, the image converter may further include a memory and a data accumulator which generates the first accumulated data, and the data accumulator may generate the first accumulated data by accumulating the first map data in memory data received from the memory.

In an embodiment, the data accumulator may generate the first accumulated data by adding the first map data to the memory data.

In an embodiment, the data accumulator may generate first compensation map data by applying an increase amount to the first binary level of the first map data and applying a decrease amount to the second binary level, and generate the first accumulated data by adding the first compensation map data to the memory data.

In an embodiment, the increase amount may be greater than the decrease amount.

In an embodiment, the image converter may further include a scaler which generates the second accumulated data by down-scaling the first accumulated data every refresh cycle, and the refresh cycle may correspond to p frame periods, and p may be an integer greater than 1.

In an embodiment, a resolution of unit data corresponding to each pixel among the memory data in the memory may be smaller than p.

In an embodiment, the image converter may further include a cut-off unit which generates the third accumulated data by initializing the values smaller than the first threshold value among the second accumulated data to be the background value, and the background value may be the same as the second binary level.

In an embodiment, the memory may store the third accumulated data as the memory data.

In an embodiment, the image converter may further include a logo determining unit which generates the second map data, and the logo determining unit may generate the second map data by replacing values greater than a second threshold value among the third accumulated data with the first binary level and replacing values less than the second threshold value among the third accumulated data with the second binary level.

In an embodiment, the image converter may further include a grayscale converter which generates the second image by specifying the pixels corresponding to the logo based on the second map data and converting grayscales of specified pixels among the first image, and the grayscale converter may specify pixels corresponding to the first binary level among the second map data as the pixels corresponding to the logo.

In an embodiment, the grayscale converter may generate the second image by reducing grayscales of the pixels corresponding to the logo among the first image.

An embodiment of a driving method of a display device according to the invention includes: generating first accumulated data by accumulating first map data corresponding to a logo area larger than a logo among a first image during a plurality of frame periods; generating second accumulated data by scaling the first accumulated data every refresh cycle; generating third accumulated data by initializing values smaller than a first threshold value among the second accumulated data to be a background value; specifying pixels corresponding to the logo based on second map data corresponding to the third accumulated data; and generating a second image by correcting grayscales of specified pixels corresponding to the logo among the first image.

In an embodiment, the driving method may further include generating the first map data in which pixels identified as the logo among the logo area are indicated as a first binary level and pixels identified as a background among the logo area are indicated as a second binary level.

In an embodiment, the generating the first accumulated data may include generating first compensation map data by applying an increase amount to the first binary level of the first map data and applying a decrease amount to the second binary level, and generating the first accumulated data by adding the first compensation map data to the memory data, where the increase amount may be greater than the decrease amount.

In an embodiment, the refresh cycle may correspond to p frame periods, where p may be an integer greater than 1. In such an embodiment, a resolution of unit data corresponding to each pixel among the memory data may be smaller than p.

In an embodiment, the background value may be the same as the second binary level, and the driving method may further include storing the third accumulated data as the memory data.

In an embodiment, the driving method may further include generating the second map data by replacing values greater than a second threshold value among the third accumulated data with the first binary level and replacing values less than the second threshold value among the third accumulated data with the second binary level.

In an embodiment, the generating the second image may include reducing the grayscales of the specified pixels corresponding to the logo among the first image.

