Semiconductor Energy Laboratory Co., Ltd.

Mai Osada

Shunpei Yamazaki

Jun Koyama

Mitsuaki Osame

Kazutaka Inukai

Yasuyuki Arai

Akira Tsunoda

There is provided a semiconductor device including a first pixel and a second pixel each including a transistor and an EL element including a pixel electrode electrically connected to the transistor. A ratio of a channel width (W) to a channel length (L) of the transistor in the first pixel is different from a ratio of a channel width (W) to a channel length (L) of the transistor in the second pixel.

Light-emitting device

There is provided a light emitting device in which low power consumption can be realized even in the case of a large screen. The surface of a source signal line or a power supply line in a pixel portion is plated to reduce a resistance of a wiring. The source signal line in the pixel portion is manufactured by a step different from a source signal line in a driver circuit portion. The power supply line in the pixel portion is manufactured by a step different from a power supply line led on a substrate. A terminal is similarly plated to made the resistance reduction. It is desirable that a wiring before plating is made of the same material as a gate electrode and the surface of the wiring is plated to form the source signal line or the power supply line.

Light emitting device and method of manufacturing the same

There is provided an EL light-emitting device with less uneven brightness. When a drain current of a plurality of current controlling TFTs is Id, a mobility is &#x3bc;, a gate capacitance per unit area is Co, a maximum gate voltage is Vgs, a channel width is W, a channel length is L, an average value of a threshold voltage is Vth, a deviation from the average value of the threshold voltage is &#x394;Vth, and a difference in emission brightness of a plurality of EL elements is within a range of &#xb1;n %, a semiconductor display device is characterized in that 

The present invention is intended to suppress power consumption of an EL display. In accordance with the brightness of an image to be displayed in a pixel portion, the contrast of the image is determined whether to be inverted or not, and the number of bits of the digital video signal to be input into the pixel portion is reduced, and the magnitude of a current to flow through the EL element is allowed to be maintained at a constant level even when a temperature of an EL layer changes by providing the EL display with another EL element to be used for monitoring a temperature.

Display device

The number of operation keys is normally on the order of 12 to 20, corresponding to numeral keys and specialized keys, even for a portable telephone device capable of sending signals to, and receiving signals from, the Internet. In order to input Japanese language characters, including kanji, and specialized characters as data, a complex operation is necessary for switching the input mode. With the present invention, display devices are formed in operation keys for inputting information to electronic devices such as portable information terminals, typically portable telephone devices, and information terminals, typically personal computer or stationary telephone devices. A user is able to recognize the operation keys by characters, symbols, and numerals displayed in the operation keys by the display devices. The user is able to recognize the operation keys even in a dark location in accordance with the present invention.

Electronic device and method of usage thereof

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.

Electro-optical device

There is provided an EL light-emitting device with less uneven brightness. When a drain current of a plurality of current controlling TFTs is Id, a mobility is &#x3bc;, a gate capacitance per unit area is Co, a maximum gate voltage is Vgs, a channel width is W a channel length is L, an average value of a threshold voltage is Vth, a deviation from the average value of the threshold voltage is &#x394;Vth, and a difference in emission brightness of a plurality of EL elements is within a range of &#xb1;n %, a semiconductor display device is characterized in that 

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Kanagawa, Japan

Mai Osada