Abstract: An electro-optical device having a plurality of pixels including a plurality of EL elements, wherein the electro-optical device provides a gray scale display by controlling a period of time at which the plurality of the EL elements emit light in one frame period; the plurality of the EL elements have a first electrode and a second electrode; the first electrode is held at a constant potential; and a potential of the second electrode changes in such a manner that a polarity of an EL driving voltage, which is a difference between the potentials applied to the first and second electrodes, is inverted for each one frame period.

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: To provide a self-luminous device capable of clear, multi-gray scale, color display and an electric machine provided with the same. Gray scale display is attained by a time division driving method in which an EL element (109) provided in a pixel (104) is controlled to emit light or not to emit light by means of time, thereby avoiding being affected by fluctuation in characteristic in current controlling TFTs (108).

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: A light emitting device is provided, in which a change of luminance of an OLED is suppressed and a desired color display can be stably performed even if an organic light emitting layer is somewhat deteriorated or an environmental temperature is varied. Separately from a pixel portion for displaying an image, a pixel portion for measuring a driving current of the OLED is provided in the light emitting device. The driving current is measured in the pixel portion for measuring the driving current of the OLED, and a value of the voltage supplied to the above two pixel portions from a variable power supply is corrected such that the measured driving current has a reference value. With the above-described structure, a reduction of the luminance accompanied with the deterioration of the organic light emitting layer can be suppressed. As a result, a clear image can be displayed.

Abstract: An object of the present invention is to provide a method for shortening a setting time of an analog current to be outputted in a DA converter circuit which reads in digital voltage value data and outputs analog current value data. The present invention can be used for a data driver circuit in an AM type OLED display device.

Abstract: [Object] The invention provides a current data amplifier circuit of which output current value is accurate even when transistors with large variation in electrical characteristics are used.

Abstract: A display device capable of displaying a picture of vivid colors maintaining a good balance of colors and a good balance of light-emitting brightnesses of the EL elements. The widths of the detour wirings supplying current to the power source feed lines are increased for those EL elements into which a current of a large density flows. This constitution decreases the wiring resistances of the detour wirings, decreases the potential drop through the detour wirings, and suppresses the amount of electric power consumed by the detour wirings.

Abstract: An active matrix light emitting device which is capable of clear color display of multiple gray scales is provided. The light emitting device has a pixel portion, and the pixel portion has a plurality of pixels. Each of the plurality of pixels has an EL element, a first EL driver TFT, a second EL driver TFT, a switching TFT, and an erasure TFT. The first EL driver TFT and the second EL driver TFT are connected in parallel.

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 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: An active matrix light emitting device which is capable of clear color display of multiple gray scales is provided. The light emitting device has a pixel portion, and the pixel portion has a plurality of pixels. Each of the plurality of pixels has an EL element, a first EL driver TFT, a second EL driver TFT, a switching TFT, and an erasure TFT. The first EL driver TFT and the second EL driver TFT are connected in parallel.

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: A light emitting device is provided, in which a change of luminance of an OLED is suppressed and a desired color display can be stably performed even if an organic light emitting layer is somewhat deteriorated or an environmental temperature is varied. Separately from a pixel portion for displaying an image, a pixel portion for measuring a driving current of the OLED is provided in the light emitting device. The driving current is measured in the pixel portion for measuring the driving current of the OLED, and a value of the voltage supplied to the above two pixel portions from a variable power supply is corrected such that the measured driving current has a reference value. With the above-described structure, a reduction of the luminance accompanied with the deterioration of the organic light emitting layer can be suppressed. As a result, a clear image can be displayed.

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: A self light emitting device in which pseudo contours are not easily generated, and a method of driving the self light emitting device, are provided. In order to prevent visualization of display irregularities such as pseudo contours, sub-frame periods are divided in order from the longest, and the sub-frame periods which have been divided (divided sub-frame periods) are distributed within the one frame period in order not to appear consecutively. Then, from among a plurality of divided sub-frames, data read in during the first divided sub-frame period is stored in memory of each pixel, and the stored data is read out during other divided sub-frame display periods and display is performed. Observation of display hindrances such as pseudo contours conspicuous in time division driving by a binary code method can thus be prevented in accordance with the above structure.

Abstract: A current data compression circuit of which output current value is accurate even when transistors with large variations in electrical characteristics are used. The current data compression circuit is an electronic circuit comprising a drive element including a plurality of transistors and a means for switching over a series connection state and a parallel connection state of the transistors. An inputted current is compressed for output by the current data compression circuit. Or, the current data compression circuit is an electronic circuit comprising a drive element including a plurality of transistors in which the transistors are used in parallel connection states when inputting current and in series connection states when outputting current.

Abstract: The present invention provides an inexpensive light emitting device and an inexpensive electric appliance. By reducing the number of photolithography steps in the fabrication of TFTs, the yield of the light emitting devices can be enhanced and the manufacturing period can be shortened. The present invention is substantially characterized in that a gate electrode is formed of a conductive film made of a plurality of layers and the concentration of impurity regions formed in the inside of an active layer can be adjusted by making use of the selection ratio at the time of etching these layers.

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 a 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.