Display device

A display device comprising:

• a housing;
• a flexible display panel, coupled to the housing, and is to display a reference image and an output image, the flexible display panel having an exposed area with a size that varies with movement of the flexible display panel in a first direction;
• a light receiving sensor to sense the reference image and to generate sensing data based on the reference image, the light receiving sensor being in the housing;
• and
• an area calculator to calculate the exposed area of the flexible display panel based on the sensing data, the area calculator connected to the light receiving sensor, wherein
• the flexible display panel includes a first display region to display the reference image and a second display region to display the output image,
• the first display region includes first to Nth dummy blocks,
• the reference image is to be displayed through the first to Nth dummy blocks,
• the first to Nth dummy blocks are sequentially arranged in a third direction opposite to the first direction,
• the first to Mth dummy blocks among the first to Nth dummy blocks are externally exposed from the housing, and the (M+1)th to Nth dummy blocks among the first to Nth dummy blocks are in the housing, wherein N≥2 and 2≤M<N,
• the reference image includes block reference images sequentially and respectively displayed by the first to Nth dummy blocks,
• the light receiving sensor is in the housing and faces the (M+1)th dummy block, the light receiving sensor to sense turning on of the (M+1)th dummy block to generate the sensing data, and
• the area calculator is to:
• count from 1 to M in synchronization with sequential turning on of the block reference images of the first to Mth dummy blocks,
• stop counting in response to the sensing data and calculate a previously counted number M as a block reference image displaying number, and
• calculate the exposed area based on the block reference image displaying number.