Patent ID: 8497854
Filing Date: 2013-07-30
Classification: G09G

Abstract:
1. a display drive apparatus for driving display pixels each having an optical element and a pixel drive circuit having a drive transistor including a first control terminal and a first current path, a diode connecting transistor including a second control terminal and a second current path, and a capacitive element, wherein a first end of the first current path is connected to the optical element, a supply voltage is applied to a second end of the first current path, a select signal is supplied to the second control terminal, a first end of the second current path is connected to the first end of the first current path, a second end of the second current path is connected to the second end of the first current path, and the capacitive element is provided between the first control terminal and the first end of the first current path, the display drive apparatus comprising: a select driver that supplies the select signal to the pixel drive circuit; a power supply driver that supplies the supply voltage to the pixel drive circuit; a detection voltage applying circuit that applies a predetermined detection voltage to the drive transistor of the pixel drive circuit; a voltage detecting circuit that detects a voltage value corresponding to a device characteristic unique to the drive transistor after a predetermined time elapses after the application of the detection voltage to the drive transistor by the detection voltage applying circuit; and a gradation designating signal generating circuit that generates a gradation designating signal based on an absolute value of a voltage component according to a gradation value of display data and a value, acquired by multiplying an absolute value of the voltage value detected by the voltage detecting circuit, by a constant set to a value of at least 1.05 and at most 1.11, and applies the gradation designating signal to the pixel drive circuit so that charges corresponding to the gradation designating signal are stored in the capacitive element; wherein: the power supply driver (i) sets a potential of the supply voltage to a first potential which sets the optical element in a non-operation state, when the detection voltage applying circuit applies the detection voltage and the voltage detecting circuit detects the voltage value and when the gradation designating signal generating circuit applies the gradation designating signal to the pixel drive circuit, and (ii) sets the potential of the supply voltage to a second potential, which differs from the first potential and sets the optical element in an operable state, when the optical element is operated in accordance with the gradation designating signal; the select driver (i) supplies to the pixel drive circuit the select signal with a potential of a selection level, which sets the diode connecting transistor in an on state, to set the drive transistor in a diode connected state when the detection voltage applying circuit applies the detection voltage and the voltage detecting circuit detects the voltage value and when the gradation designating signal generating circuit applies the gradation designating signal to the pixel drive circuit, and (ii) supplies to the pixel drive circuit the select signal with a potential of a non-selection level, which sets the diode connecting transistor in an off state and differs from the selection level, to release the diode connected state of the drive transistor when the optical element is operated in accordance with the gradation designating signal; and in the gradation designating signal generating circuit, the constant is set to a value that compensates for a change in the charges stored in the capacitive element, which change occurs due to the potential of the supply voltage changing from the first potential to the second potential and the potential of the select signal changing from the selection level to the non-selection level when the optical element is operated in accordance with the gradation designating signal.