Matsushita Electric Industrial Co., Ltd.

Kouji Senda

Yutaka Nanno

Shin-itsu Takehashi

Hiroshi Tsutsu

An EL display deviceincludes a display portionhaving unit pixelsarranged in a matrix, a source line driver circuit, and a gate line driver circuit. Each of the unit pixelshas an EL element, a switching transistor Tr, a driver transistor Tr, and an auxiliary capacitor. The auxiliary capacitorhas electrodes, one connected to a gate electrode of the transistor Trand the other to a next gate line GL. The gate line driver circuitoutputs, via the next gate line GL, blanking signals for forcibly stopping a light-emitting state of the EL elements, within hold times in which the voltages written to the gate electrodes of the transistors Trare held. With such a configuration, a blanking period where the EL elements do not emit light, is inserted in one frame.

EL display device providing means for delivery of blanking signals to pixel elements

An active matrix liquid crystal display device has a plurality of unit pixels being arranged in a matrix configuration, each unit pixel being divided into a plurality of subpixels. Each of the subpixels has a subpixel electrode, a pixel transistor connected to the subpixel electrode, and a voltage controlling capacitor connected to the subpixel electrode. A voltage controlling capacitor line for supplying a compensation voltage signal is connected to the voltage controlling capacitor so that after the writing to the subpixel has been completed, the potential of the compensation voltage signal is varied to modulate the potential of the subpixel electrode to be a predetermined voltage, using the voltage controlling capacitor. Such combining of spatial dithering attained by a pixel-dividing technique and a capacitively-coupled driving method eliminates the need for digital-to-analog converter circuits, attains gray scale display based on a digital image signal, and achieves a reduction in power consumption.

Liquid crystal display device, electroluminescent display device, method of driving the devices, and method of evaluating subpixel arrangement patterns

A unit pixel () includes a plurality of current controlling elements (Tr&#x2013;Tr) having controlling terminal and connected to a single EL element (), and switching elements (Tr&#x2013;Tr) provided to the respective current controlling elements in order to switch between application and cutoff of a digital image signal with respect to the controlling terminals in accordance with the condition of a scanning signal. Each of the current controlling elements is controlled by a voltage of the digital image signal so as to take an OFF state for cutting off a supply of a driving current to the EL element or an ON state for supplying the EL element with a driving current corresponding to the voltage of the digital image signal, and a value of the current flowing in the EL element is the sum value of currents supplied from the respective current controlling elements in the ON state. Based on a combination of the current controlling elements in the ON state, the current supplied to the EL element is controlled to be a value corresponding to the gradation.

Active matrix EL display device and method of driving the same

The present invention provides a liquid crystal display device having a liquid crystal display portion, a gate driver circuit, a source driver circuit, and a power supply circuit, where the liquid crystal display portion includes unit pixels with pixel switching elements and pixel electrodes arranged in a matrix. The pixel switching elements are thin film transistors that are made of polycrystalline silicon semiconductor formed on an insulating substrate. The power supply circuit is a charge pump-type power supply circuit, is made of a polycrystalline silicon semiconductor, and is a built-in circuit integrally formed on an insulating substrate. With such a configuration, a liquid crystal display device that greatly reduces power consumption is realized.

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Nagaokakyo, Japan

Kouji Senda