Abstract: To provide an electronic device capable of bright image display. A pixel is structured such that a switching TFT and a current controlling TFT are formed on a substrate and an EL element is electrically connected to the current controlling TFT. A gate capacitor formed between a gate electrode of the current controlling TFT and an LDD region thereof holds a voltage applied to the gate electrode, and hence a capacitor (condenser) is not particularly necessary in the pixel, thereby making the effective light emission area of the pixel large.

Abstract: A simple DA converter circuit which reads in digital voltage value data and outputs analog current value data is provided. The DA converter circuit according to the invention can be applied, for example, to a data driver circuit of an AM-OLED display device. The DA converter circuit comprises a current output circuit comprising a plurality of drive transistors. Gate electrodes of the transistors are electrically connected to each other, and a switch is provided between the gate electrode and drain electrode of each drive transistor.

Abstract: To provide an electronic device capable of suppressing a luminous amount of an EL element and realizing a large number of gray-scale levels. The electronic device is characterized in that the luminescence of the EL element is controlled by a pair of EL driver TFTs, one of the pair of EL driver TFTs is controlled by one of the pair of switching TFTs and one of the pair of eliminating TFTs, the other of the pair of EL driver TFTs is controlled by the other of the pair of switching TFTs and the other of the eliminating TFTs, and gray-scale display is performed by controlling the luminescence time of the EL elements.

Abstract: A current-input light-emitting device of the invention converts a current corresponding to a given video signal to a voltage by passing the current between two nodes of four nodes of a multi-terminal transistor, converts the voltage to a current again by shorting the other two nodes different and supplies the current to a light-emitting element. A threshold-corrected, voltage-input light-emitting device shorts two nodes of four nodes of a multi-terminal transistor to write a threshold value voltage into a storage capacitor and to write a voltage corresponding to a given video signal into the storage capacitor. Next, the other two nodes are shorted, and the voltage of the two nodes is converted to a current. Then the current is supplied to a light-emitting element.

Abstract: The light emitting device according to the present invention is characterized in that a gate electrode comprising plurality of conductive films is formed, and concentration of impurity regions in an active layer are adjusted with making use of selectivity of the conductive films in etching and using them as masks. The present invention reduces the number of photolithography steps in relation to manufacturing the TFT for improving yield of the light emitting device and shortening manufacturing term thereof, by which a light emitting device and an electronic appliance are inexpensively provided.

Abstract: To provide a display device and its driving method free from lack of writing time, which usually accompanies an increase in size of a display device and enhancement in definition. Therefore, there is provided a display device and a driving method in which x (x is a natural number equal to or larger than 4) data lines are placed in each column to simultaneously supply video signals to x pixels through the x data lines. The present invention makes it possible to supply video signals to x pixels simultaneously as opposed to conventional dot sequential driving where a signal is supplied to one pixel at a time. Furthermore, a display device of the present invention and its driving method make it possible to supply video signals to (x×n) pixels at once as opposed to conventional linear sequential driving where only n pixels in the first to last (the last column is the n-th column) columns receive signals simultaneously.

Abstract: There is provided a light emitting device including a TFT having a high driving capacity (on current) and high reliability in a driver circuit and a TFT in which an off current is reduced in a pixel portion. In manufacturing the TFTs, after the TFT having an LDD region is formed, a part of a gate electrode is etched to form the TFT having GOLD region. Thus, the TFTs having required functions can be easily formed in the driver circuit and the pixel portion, respectively, on the same substrate.

Abstract: There is provided an electronic device in which the deterioration of the device is prevented and an aperture ratio is improved without using a black mask and without increasing the number of masks. In the electronic device, a first electrode (113) is disposed on another layer different from the layer on which a gate wiring (145) is disposed as a gate electrode, and a semiconductor layer of a pixel switching TFT is superimposed on the gate wiring (145) so as to be shielded from a light. Thus, the deterioration of the TFT is suppressed, and a high aperture ratio is realized.

Abstract: An EL display device capable of clear, multi-gradation color display, and an electronic device having the EL display device, are provided. Gradation display is performed in accordance with a time division driver method which controls by the amount of time an EL element formed in a pixel emits light, and the amount of time it does not emit light. Influence due to dispersion in the characteristics of electric current TFTs is prevented.

Abstract: There is provided a light emitting device which is bright and has low electric power consumption and high reliability. A triplet EL element 203 electrically connected to a current controlling TFT 102 is provided in a pixel portion 201. A luminescent material used for the triplet EL element 203 has a feature that EL is obtained by triplet excitation, and exhibits high luminous efficiency at a low operation voltage as compared with the prior art. Accordingly, the operation is made at the low operation voltage, so that the light emitting device which is bright and has low electric power consumption and high reliability can be obtained.

Abstract: To provide an electronic device capable of bright image display. A pixel is structured such that a switching TFT and a current controlling TFT are formed on a substrate and an EL element is electrically connected to the current controlling TFT. A gate capacitor formed between a gate electrode of the current controlling TFT and an LDD region thereof holds a voltage applied to the gate electrode, and hence a capacitor (condenser) is not particularly necessary in the pixel, thereby making the effective light emission area of the pixel large.

Abstract: A novel driving method for conducting gradation display is provided. Also, a signal line driver circuit is provided which includes a current source circuit having a small area. Further, miniaturization and reduction in size of a frame of a light-emitting device can be attained. A gate selection period is divided into plural periods, and a (writing) operation of writing a signal to a pixel having a transistor connected with a scanning line that is selected and a (reading) operation of reading a signal current into a current source circuit connected with a signal line connected with a scanning line that is not selected are performed simultaneously in each of the divided periods in the gate selection period. Therefore, the signal line driver circuit that includes a current source circuit having a small area is provided. Consequently, the miniaturization and reduction in size of the frame of the light-emitting device can be attained.

Abstract: There is provided an electronic device having high reliability and high color reproducibility. A pixel structure is made such that a switching FET (201) and an electric current controlling FET (202) are formed on a single crystal semiconductor substrate (11), and an EL element (203) is electrically connected to the electric current controlling FET (202). The fluctuation in characteristics of the electric current controlling FET (202) is very low among pixels, and an image with high color reproducibility can be obtained. By taking hot carrier measures in the electric current controlling FET (202), the electronic device having high reliability can be obtained.

Abstract: An EL display device free of a dispersion in the brightness caused by deterioration in the EL elements. The display device uses pixels of the current-controlled type to suppress a change in the current flowing through the EL elements caused by the deterioration in the EL elements. The display device further uses elements capable of short-circuiting or opening three nodes simultaneously. No bank is used for dividing the EL layers into separate colors. EL elements of the mixed junction type are used. A reverse bias voltage is applied to the EL elements at regular intervals. The display device suppresses dispersion in the brightness caused by the deterioration in the EL elements.

Abstract: An AM-OLED display device is provided in which dispersion in OLED element driver currents is sufficiently suppressed is taken as an objective. The present invention places a plurality of transistors into a parallel connection state during write-in of a data current into pixels, and places the plurality of transistors into a series connection state when light emitting elements emit light. As a result, even if dispersions exist between the plurality of transistors structuring a driver element within the same pixel, the influence of the dispersions can be greatly suppressed, and therefore irregularities in the brightness of emitted light across pixels, of an order such that it causes problems in practical use, can be prevented.

Abstract: To provide an electronic device capable of suppressing a luminous amount of an EL element and realizing a large number of gray-scale levels. The electronic device is characterized in that the luminescence of the EL element is controlled by a pair of EL driver TFTs, one of the pair of EL driver TFTs is controlled by one of the pair of switching TFTs and one of the pair of eliminating TFTs, the other of the pair of EL driver TFTs is controlled by the other of the pair of switching TFTs and the other of the eliminating TFTs, and gray-scale display is performed by controlling the luminescence time of the EL elements.

Abstract: There is provided an electronic device having high reliability and high color reproducibility. A pixel structure is made such that a switching FET (201) and an electric current controlling FET (202) are formed on a single crystal semiconductor substrate (11), and an EL element (203) is electrically connected to the electric current controlling FET (202). The fluctuation in characteristics of the electric current controlling FET (202) is very low among pixels, and an image with high color reproducibility can be obtained. By taking hot carrier measures in the electric current controlling FET (202), the electronic device having high reliability can be obtained.

Abstract: A current storing circuit capable of having a small area, a simple structure with the small number of devices, a low consumption current operation and high yield in manufacturing is provided. Applying the current storing circuit to the current-driving type of display device such as an OLED display device can improve the aperture rate of pixels and reliability of the display device as well as highly functionalize the display device. The invention is characterized by using a new semiconductor element in a shape of a transistor having plural drains or sources. When the semiconductor elements is used for both of a writing element and a driving element, reading in and storing a current value and outputting the current can be performed by only the two semiconductor elements, so that the area occupied by the devices would be easily reduced significantly.

Abstract: To provide an electronic device capable of suppressing a luminous amount of an EL element and realizing a large number of gray-scale levels. The electronic device is characterized in that the luminescence of the EL element is controlled by a pair of EL driver TFTs, one of the pair of EL driver TFTs is controlled by one of the pair of switching TFTs and one of the pair of eliminating TFTs, the other of the pair of EL driver TFTs is controlled by the other of the pair of switching TFTs and the other of the eliminating TFTs, and gray-scale display is performed by controlling the luminescence time of the EL elements.

Abstract: A switching element is provided, which is capable of short-circuiting or opening three or more nodes simultaneously, and in which the surface area occupied on a substrate can be reduced. The switching element of the present invention has an active layer, an insulating film contacting the active layer, a gate electrode contacting the insulating film, and three or more connection electrodes. The active layer has at least one channel forming region and three or more impurity doped regions, and the connection electrodes are each connected to a different impurity region. An impurity region contacting an arbitrary connection electrode contacts only one of the channel forming regions.