Sanyo Electric Co., Ltd.

Sanjo Electric Co., Ltd.

Yusuke Tsutsui

Makoto Kitagawa

Mitsugu Kobayashi

Hisao Uehara

Ryoichi Yokoyama

Takeo Yoshimura

Michiru Senda

Makoto Shimizu

Makoto Fujioka

Shoichiro Matsumoto

Kazuto Noritake

Masashi Mitsui

Yasuki Rai

Yasushi Marushita

Kenji Saiki

Hikaru Akutsu

Tamotsu Uekuri

There is provided a display device which enables both a full color moving image display (analog mode) and a shallow depth still image display (digital mode), and which achieves a significant reduction in the energy consumption of the display device system including the external LSI. Each of the pixel elements of the display device has two different display circuits corresponding to the respective display modes and a switching circuit for selecting one of them. When the digital mode is selected, the supply of the voltage power to the circuits not required to operate (a DA converter, a operational amplifier and a timing controller) under the mode is halted for reducing the consumption of the electric power by the display device.

Display device and its control method

Power consumption in an active matrix type liquid crystal display device having partial display function is reduced. In one frame period, a display area corresponding to first 80 horizontal periods, that is the first line through the 80th line, is set as a partial display area and a display area corresponding to the remaining 239 lines is set as a background display area. And a partial display area control signal ENBSC is set at a low level and an SC inversion drive is performed in the partial display area. The partial display area control signal ENBSC is fixed at a high level in the background display area and all of SC inversion control units corresponding to the background display area halt their operation.

Active matrix type liquid crystal display device

A display capable of rendering flickering hard to visually recognize, reducing power consumption and simplifying the structure of a circuit for negatively/positively reversing an image is provided. This display comprises a plurality of drain lines and a plurality of gate lines, a first pixel portion and a second pixel portion each including a subsidiary capacitor having a first electrode and a second electrode and a first subsidiary capacitance line and a second subsidiary capacitance line connected to the subsidiary capacitors of the first pixel portion and the second pixel portion respectively. The display also comprises a signal supply circuit supplying either a first signal or a second signal for negatively/positively reversing an image to the first subsidiary capacitance line of the first pixel portion when displaying the image while supplying either a third signal or a fourth signal for negatively/positively reversing the image to the second subsidiary capacitance line of the second pixel portion when reversing the image.

Liquid crystal display capable of making flicker difficult to be observed and reducing power consumption

In the active matrix display device with a DRAM as the retaining circuit, the voltage retained in the retaining circuit is set in the brightness saturation region, which is outside the region of the voltage used in the moving picture display mode. With the voltage in this region, the difference in the brightness will not be recognized even if the voltage decreases before the refreshing operation. This prevents flickering and improves the display quality.

Active matrix display device

A power supply circuit () for a display device such as a liquid crystal outputs a boosted supply voltage VDDduring normal operation, and generates a non-boosted supply voltage VDDhaving a voltage lower than that during the normal display operation by controlling the switches for switching the output within the power supply circuit () during a power save mode. The non-boosted supply voltage is supplied to the analog circuits of a driving circuit () so that the power consumption at the analog circuits is reduced. By controlling the switch for switching the output within the power supply circuit and the supply of the power supply clock, the circuit can be switched, in the power save mode, to either a mode where a lower supply voltage is generated or to a mode where the power supply is turned off.

Driving apparatus for display device

A liquid crystal display device has a liquid crystal panel, a DA converter for generating a common electrode signal to be applied to a common electrode of a liquid crystal, and a non-volatile memory for encoding an optimum value of the common electrode signal into an ID code and storing the ID code therein. The DA converter generates the optimum common electrode signal corresponding to the ID code read out from the non-volatile memory. A liquid crystal panel manufacturer ships the liquid crystal panel in which the optimum value of the common electrode signal is encoded into the ID code and stored in the non-volatile memory in an inspecting process. The assembling manufacturer using the liquid crystal panel can easily set the optimum value of the common electrode signal. Furthermore, the liquid crystal display device has a CPU decoding the ID code read out from the non-volatile memory. Alternatively, it is possible to supply a data of a value of the common electrode signal to a user of the liquid crystal. The user adjusts the common electrode signal generating circuit by using the data of the value of the common electrode signal.

Liquid crystal display device and adjusting method of the same

A mask circuit is provided in a display device having a plurality of pixels. The mask circuit supplies a video signal to each of the pixels in a partial display area selected based on a display area selection signal, and prevents the supply of the video signal to each of the pixels in a background display area. Accordingly, this display device displays an arbitrary pattern at an arbitrary position of the display panel of the display device. In addition, an inverting controlling circuit is provided for inverting the background display signal supplied to each of the pixels in the background display area for each frame. The power consumption of the display device can be reduced.

Display device

The display device of this invention has a pixel element electrodea plurality of drain signal linesfor supplying the digital image signals D&#x2013;D, a plurality of capacitance elements C&#x2013;Cwith weighed capacitance value corresponding to the digital image signals D&#x2013;Da refresh transistor RT for initializing the voltage of the pixel element electrodeto the voltage Vsc, and charge transfer transistors TT&#x2013;TTfor supplying the charge accumulated in the capacitance elements C&#x2013;Cto the pixel element electrode. An image is displayed by supplying the analog image signal corresponding to the digital image signals D&#x2013;Dto the pixel element electrode. The configuration of the peripheral circuits of the pixel element portion is simplified, leading to the reduction of the framing area of the panel.

A display device, under a digital display mode, performs writing of digital image signals into a static memory circuit while a power voltage of about 3V is applied to the static memory with a panel drive frequency reduced from 60 Hz to 20&#x2013;30 Hz. It is thus possible to output the digital image signal from a frame memory directly to a liquid crystal display panel without using a level shifter.

A display device has a power line providing a retaining circuit with a power voltage, which is also used as a storage capacitance line connected to one of the electrodes of a storage capacitor. The storage capacitance line is disposed parallel to gate signal lines in a pixel element of the device. The power line of two inverter circuits, which form the retaining circuit, extends in the direction perpendicular to the storage capacitance line and is connected to the storage capacitance line. This configuration helps to reduce the overall size of the display device.

A surface-pressure distribution sensor includes a plurality of unit detection elements placed in a sensor area of a substrate and a switch formed on the substrate. The sensor is configured to operate under an operation mode in which the unit detection elements are sequentially selected or a standby mode in which the unit detection elements are not selected. The sensor is also configured to alternate between the two modes. The switch is configured change the standby mode to the operation mode when the switch is operated on.

Surface-pressure distribution sensor and method for controlling operation thereof

The switching between the normal operation mode and the memory operation mode is achieved by disposing one retaining circuitfor a plurality of pixel elements (for example, 2 or 4 pixel elements). The retaining circuit, which is a SRAM, requires considerable circuit space. The sharing of one retaining circuit by a plurality of the pixel elements enables the reduction of the seeming 'number of the pixel elements' under the memory operation mode. This can lead to the size reduction of the pixel element, achieving the finer display under the normal operation mode. Also, the reduction in the number of the retaining circuits can further reduce the energy consumption under the memory operation mode, comparing to the case where the retaining circuitis disposed for each of the pixel elements.

Active matrix display device with shared retaining circuit

The display device of this invention has two types of DA converter for converting a digital image signal to an analog image signal; a first DA converter disposed in the peripheral area of a plurality of pixel elements and a second DA converter disposed within each of the pixel elements. The first DA converter converts the upper four-bit of a six-bit digital image signal and the second DA converter converts the remaining lower two-bit. This enables the simplification of the peripheral circuits of the pixel element, preventing size increase of the framing area of the display panel, while achieving the multiple-depth display with an increased number of the bits of the DA converter. In the display device with the built-in DA converter, the multiple-bit can be achieved while preventing the increase in the circuit size.

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Hashima, Japan

Yusuke Tsutsui