Sanyo Electric Co., Ltd.

Koji Marumo

Masayuki Koga

Michiru Senda

Yukio Mori

Haruhiko Murata

Susumu Tanase

Keiichi Sano

Atsuhiro Yamashita

Kazunobu Mameno

Kenya Uesugi

Kuni Yamamura

A display device has: an RGB-RGBW conversion circuit that converts RGB signals fed thereto into RGBW signals; a display panel that has a plurality of dots each composed of four, namely R, G, B, and W, unit pixels and that displays an image based on the RGBW signals; a defect position specifier that specifies, if a unit pixel is found defective, a position of the defective pixel on the display panel; and a conversion rate controller that controls the rate at which, when the RGB signals are converted into the RGBW signals, the RGB signals are converted into a W signal according to the position of the defective pixel. If the defective pixel is a W pixel, the conversion rate for pixels adjacent thereto is made lower than the standard conversion rate set for the entire display panel.

Display device

When a selection TFT and a correction TFT are turned on, a data voltage of a data line is stored in a storage capacitor as a gate voltage of a driving TFT. After turning off the selection TFT, a voltage of a capacitor line SC falls, thereby turning on the driving TFT to supply a driving current to an organic EL element. The correction TFT is in the ON state before the capacitor line SC falls, and is turned off in the course of the fall of the line. Consequently, the capacitance of the correction TFT changes during the fall of the gate voltage, and the gradient of the gate voltage fall of the driving TFT is changed, thereby setting the gate voltage after the capacitor line SC falls in accordance with variation in threshold of the driving TFT. Particularly by disposing the driving TFT and the correction TFT adjacent to each other, the two TFTs are provided with the same properties to achieve effective correction.

Pixel circuit and display device

When a switching TFT is switched on, a data voltage on a data line is stored in a storage capacitor as a gate voltage of a driver TFT. In this state, a voltage on a pulse drive line is caused to fall. AMOS type capacity element having a second electrode connected to a reference voltage is connected to a gate of the driver TFT. The MOS type capacity element is in an ON state before a fall of the pulse drive line and becomes an OFF state during the fall, and a capacitance changes at the switching of ON state to the OFF state. Therefore, the slope of fall of the gate voltage changes, and the gate voltage after the fall on the pulse drive line can be corrected corresponding to the variation in the threshold values among driver TFTs.

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Gifu, Japan

Koji Marumo