Abstract: A circuitry and a driving method thereof in which a reverse voltage is applied to a light emitting element to control the degradation thereof and improve reliability for a display device comprising a pixel circuit. A first power source line is connected to a signal line through a switching transistor and erasing transistor, and a current controlling transistor and driving transistor are connected in series between the first power source line and a light emitting element. An analog switch including first and second transistors whose gate electrodes are connected to the first and second power source lines respectively is provided. Further, a bias transistor whose gate electrode is connected to a third power source line, one of source and drain electrodes thereof is connected to the first power source line, and the other is connected to an output terminal of the analog switch and a scan line is provided.

Abstract: It is intended to provide a light-emitting device capable of suppressing an off-current of a switching transistor and luminosity irregularity of light-emitting elements of pixels otherwise caused by variation in characteristics of the driving transistors without increasing capacitance of a capacitance element and an element substrate. A potential of a gate of the driving transistor is fixed, and the driving transistor is operated in a saturation area, so that a current can be supplied thereto anytime. A current control transistor operating in a linear area is disposed serially with the driving transistor, and a video signal for transmitting a signal of emission or non-emission of the pixel is input to a gate of the current control transistor via a switching transistor.

Abstract: The present invention provides a circuit configuration for applying a reverse voltage (or a reverse bias) for enhancing the reliability by controlling the degradation of the light emitting element in a display device having a pixel circuit, and a method thereof. A reverse voltage is applied to a pixel circuit having at least a switching transistor connected to a signal line, a driving transistor connected to a light emitting element, and a current controlling transistor connected to the driving transistor in series. A reverse voltage applying circuit includes an analog switch or a clocked inverter, and a reverse voltage applying transistor which is turned ON when a reverse voltage is applied.

Abstract: The invention provides a light emitting device and an element substrate in which a luminance variation of light emitting elements among pixels due to variation in characteristics of driving transistors can be suppressed even without suppressing the off-current of a switching transistor low or increasing the capacitance of a capacitor. A gate of a first transistor is connected to a first scan line, and a gate of a second transistor is connected to a second scan line. A connection between a signal line and a gate of a third transistor is controlled by the first transistor. The second transistor and the third transistor are connected in series between a pixel electrode of a light emitting element and a power supply line. The signal line, the second scan line and the power supply line are disposed in parallel, while the first scan line is crossed with the signal line, the second scan line and the power supply line.

Abstract: A display device in which the influence of a parasitic capacitance or a wiring capacitance is suppressed without lowering OFF-current of a switching transistor or increasing the capacitance of a capacitor, and a driving method thereof using area gray scale display in particular. The display device of the invention comprises a plurality of sub pixels each including a driving transistor whose gate potential is fixed, and area gray scale display is achieved. Specifically, each of the sub pixels comprises, in addition to the driving transistor, a switching transistor, a current controlling transistor connected in series with the driving transistor, and a light emitting element.

Abstract: No need of lowering off-current of a switching transistor, fewer luminance variations of a light emitting element between pixels due to characteristic variations of a driving transistor, and less risk of steps due to increase in the number of wirings. A video signal for light emission or non-emission of a pixel is input to a gate of a current controlling transistor operated in a linear region, which is connected in series with the driving transistor, through a switching transistor. Since a voltage Vds between a source and a drain of the current controlling transistor is small, small changes in a voltage Vgs between a gate and a source thereof do not affect a current flowing in a load. The current flowing in the light emitting element is determined by the driving transistor operated in a saturation region, and a fixed potential is input to the gate thereof during light emission.

Abstract: The invention provides a light emitting device using transistors manufactured by the conventional process while reducing an area occupied by capacitors, whereby variations in luminance of light emitting elements caused by variations in gate voltage Vgs of the transistors are suppressed, and a luminance decay of the light emitting elements due to the degradation of light emitting materials and variations in luminance can also be suppressed.

Abstract: A latch circuit is disposed to an output terminal of the respective stages of a shift register circuit, when a pulse is shifted to a stage to which an output is wanted to be outputted, a latch pulse is inputted and held there until a subsequent pulse is inputted, when the pulse is shifted to a stage to which an output is wanted to be outputted in the next time, a latch pulse is again inputted, and thereby an output stage is switched. Thus, a period to be selected and a stage to be selected can be arbitrary selected by changing a latch pulse without changing a clock frequency.

Abstract: In order to provide a display device of high reliability in which an amount of moisture and oxygen, which are a factor for deteriorating a characteristics of a display device, entering from a sealing agent is reduced and its manufacturing method, the present invention has a sealing film. Accordingly, an interlayer insulating film including an organic material of the display device (panel) is no longer exposed to the atmosphere outside of the display device. Therefore, it becomes possible to prevent moisture and oxygen outside of the display device from entering inside of the display device through an insulating film and the like including a hygroscopic organic material. In addition, various degradations such as contamination of an inner part of the display device caused by moisture, oxygen and the like, the degradation of electric properties, a dark spot and shrink can be prevented, thus enhancing reliability of the display device.

Abstract: An object of the present invention is to provide a light emitting device that is able to suppress power consumption while a balance of white light is kept, without making a configuration of a power source circuit complicated. A power source potential corresponding to each color of a light emitting element is used as a higher electric potential of a video signal and an electric potential of a power source line in the case that a transistor for controlling a supply of electric current to the light emitting element is a p-channel TFT. Conversely, a power source potential corresponding to each color of a light emitting element is used as a lower electric potential of a video signal and an electric potential of a power source line in the case that a transistor for controlling a supply of electric current to the light emitting element is an n-channel TFT.

Abstract: The light-emitting element has a problem that reliability, heat-resisting stability and durability are low because of the deterioration in an organic compound layer. The TFT for driving the light-emitting element has a problem that variation readily occurs in its electrical characteristic due to the defects existing in grain boundaries. The present invention provides a light-emitting device by using the fact that, by applying to the light-emitting element a drive voltage having a polarity reverse to that in light emission during each constant period, the light-emitting element is improved in current-voltage characteristic. Furthermore, the present invention provides a light-emitting device made not dependent upon transistor characteristic, by controlling the amount of a current flowing through the light-emitting element.

Abstract: A driving method is provided which improves the duty ratio, which presents high image quality by securing a sufficient length of sustain (lighting) period when gray scales are increased in number, and which prolongs the lifetime of a light emitting element. One frame period has m (m is a natural number equal to or larger than 2) different sub-frame periods SF1, SF2, . . . , and SFm. The m different sub-frame periods SF1, SF2, . . . , and SFm each have an address period and a sustain period. Analog data signals are inputted to their respective light emitting elements in the address period. In the sustain period, the light emitting elements emit light in response to the analog data signals at n (n is a natural number equal to or larger than 2) levels of luminance for gray scale display.