Correcting brightness variations in organic electroluminescent panel

An OLED display having a correction circuit for producing corrected image data in response to the first image data and in response to correction data to correct for brightness unevenness due to TFT variations; a memory for storing first image data or correction data; a switch effective in first and second states in response to a function switching signal having first and second conditions, respectively; and circuitry for causing the switch to be in the first state to connect the memory to the image input signal interface and to provide the stored first image data to the panel as the second image data; and for causing the switch to be in the second state to connect the memory to the correction circuit, provide the stored correction data to the correction circuit, and provide the corrected image data to the panel as the second image data.