Abstract: It is an object of the present invention to provide a display device in which images can be seen under a dark place to intense external light. In the display device, display is performed by changing the gray scale number depending on external light intensity, and display modes can be switched depending on contents displayed on the screen. An analog mode and a digital mode are switched depending on external light intensity. In an analog digital switching circuit, when a video signal is an analog value, a signal is outputted to a pixel array without any change and, when the video signal is a digital value, the signal is outputted to a circuit that performs a digital operation such as a latch circuit. Consequently, display gray scales of a pixel are changed appropriately. Accordingly, a clear image can be displayed. For example, it is possible to ensure visibility in a wide range of a dark place or under indoor florescent light to outdoor sun light.

Abstract: A light-emitting element has a property that a resistance value (internal resistance) changes in accordance with an environmental temperature. It is an object to downsize a monitoring element which corrects an influence of variations in current value of the light-emitting element, which are caused by an environmental temperature change and a change with time. A pixel includes a plurality of sub-pixels, areas of light-emitting elements provided in the individual sub-pixels are made to be different from each other, and an area of a monitoring element is made to be the same as an area of the light-emitting element in any of the sub-pixels, thereby correcting light-emission of the pixel by the monitoring element.

Abstract: It is an object of the present invention to provide a display device in which images can be seen under a dark place to intense external light. In the display device, display is performed by changing the gray scale number depending on external light intensity, and display modes can be switched depending on contents displayed on the screen. An analog mode and a digital mode are switched depending on external light intensity. In an analog digital switching circuit, when a video signal is an analog value, a signal is outputted to a pixel array without any change and, when the video signal is a digital value, the signal is outputted to a circuit that performs a digital operation such as a latch circuit. Consequently, display gray scales of a pixel are changed appropriately. Accordingly, a clear image can be displayed. For example, it is possible to ensure visibility in a wide range of a dark place or under indoor florescent light to outdoor sun light.

Abstract: Semiconductor elements deteriorate or are destroyed due to electrostatic discharge damage. The present invention provides a semiconductor device in which a protecting means is formed in each pixel. The protecting means is provided with one or a plurality of elements selected from the group consisting of resistor elements, capacitor elements, and rectifying elements. Sudden changes in the electric potential of a source electrode or a drain electrode of a transistor due to electric charge that builds up in a pixel electrode is relieved by disposing the protecting means between the pixel electrode of the light-emitting element and the source electrode or the drain electrode of the transistor. Deterioration or destruction of the semiconductor element due to electrostatic discharge damage is thus prevented.

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: Semiconductor elements deteriorate or are destroyed due to electrostatic discharge damage. The present invention provides a semiconductor device in which a protecting means is formed in each pixel. The protecting means is provided with one or a plurality of elements selected from the group consisting of resistor elements, capacitor elements, and rectifying elements. Sudden changes in the electric potential of a source electrode or a drain electrode of a transistor due to electric charge that builds up in a pixel electrode is relieved by disposing the protecting means between the pixel electrode of the light-emitting element and the source electrode or the drain electrode of the transistor. Deterioration or destruction of the semiconductor element due to electrostatic discharge damage is thus prevented.

Abstract: The amplitude of a potential of a signal line is decreased and a scan line driver circuit is prevented from being excessively loaded. A light-emitting device includes a light-emitting element; a first power supply line having a first potential; a second power supply line having a second potential; a first transistor for controlling a connection between the first power supply line and the light-emitting element; a second transistor, which is controlled in accordance with a video signal, whether outputting the second potential applied from the second power supply line or not; a switching element for selecting either the first potential applied from the first power supply line or the output of the second transistor; and a third transistor for selecting whether the first potential or the output of the second transistor which is selected by the switch is applied to a gate of the first 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: A light emitting device is provided where an area occupied by capacitors is decreased, luminance variations of light emitting elements caused by characteristics variations or fluctuations of the gate voltage Vgs of driving TFTs can be suppressed. Each of multiple pixels includes a light emitting element, a first transistor for determining a current value supplied thereto, a second transistor for selecting emission/non-emission thereof according to video signals, a first power supply line, and a second power supply line shared by the multiple pixels. In addition, a compensation circuit is provided each of which includes a third transistor whose gate and drain are connected to the second power supply line, and a fourth transistor for controlling the connection between a third power supply line and the gate and drain of the third transistor.

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 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: 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: 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 invention provides a display device in which occurrence of a display defect called a ghost is prevented, and a driving method thereof, and a television set. According to the invention, a gate control signal (GWE) which has been one signal is divided into a first gate control signal (GWE1) and a second gate control signal (GWE2), or a pulse-width control signal (PWC) is used in addition to one gate control signal (GWE) which has been used, thereby preventing a period for outputting a video signal to a pixel by a source driver and a period for selecting a gate line by an erasing gate driver from overlapping each other. Then, video signal writing to a pixel where an erasing operation is performed is prevented, so that occurrence of the display defect called a ghost is prevented.

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.

Abstract: Outside light is received using a light sensor, and in accordance with the outside light intensity, each of a first display mode which expresses multiple gray scales and a second display-y mode which expresses a gray scale smaller in number than that in the first display mode is switched and used. The switching is controlled by a display controller based on data of the outside light intensity. Accordingly, the visibility can be ensured in a wide range of situations, from under a fluorescent lamp in a dark place or inside, to under sunlight outside. In the second display mode, frequencies of a start pulse and a clock pulse to be inputted to a source signal line driver circuit are reduced and a driving voltage is decreased by the display controller; accordingly, a frame period can be longer than that in the first display mode and power consumption can be reduced.

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: 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.