Abstract: The display device of this invention has a pixel element electrode 80, a plurality of drain signal lines 61 for supplying the digital image signals D0–D2, a plurality of capacitance elements C0–C2 with weighed capacitance value corresponding to the digital image signals D0–D2, a refresh transistor RT for initializing the voltage of the pixel element electrode 80 to the voltage Vsc, and charge transfer transistors TT0–TT2 for supplying the charge accumulated in the capacitance elements C0–C2 to the pixel element electrode 80. An image is displayed by supplying the analog image signal corresponding to the digital image signals D0–D2 to the pixel element electrode 80. The configuration of the peripheral circuits of the pixel element portion is simplified, leading to the reduction of the framing area of the panel.

Abstract: 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 20–30 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: The switching between the normal operation mode and the memory operation mode is achieved by disposing one retaining circuit 110 for a plurality of pixel elements (for example, 2 or 4 pixel elements). The retaining circuit 110, 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 circuit 110 is disposed for each of the pixel elements.

Abstract: 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.

Abstract: 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.

Abstract: A driving circuit of a display device such as a liquid crystal generates power supply clocks (1 and 2) based on a system clock during the normal display operation which is not a power save mode. The generated power supply clocks are supplied, directly or after inversion, to the switches (SW1 through SW4 (and SW5 through SW8)) in a charge pump type power supply circuit (300) for switching the connection of capacitors (C1 and C2 (and C11 and C12)) in the power supply circuit (300). In this manner, supply voltages VDD2 and VDD3 which function as the driving power supply for a driving circuit (100) and a display panel (200) can be obtained at the power supply circuit (300) by boosting the input voltage Vin.

Abstract: A liquid crystal display apparatus includes a liquid crystal display panel having preset display characteristics, such as image brightness and contrast. A luminescent unit is optically connected with the display panel and provides light to the display panel in order to form an image on the display panel. The luminescent unit includes a light collector which collects ambient light and a light source, for generating light when the amount of ambient light is insufficient to generate a clear image. A control circuit is electrically connected to the display panel and automatically varies the preset display characteristics in accordance with the amount of ambient light collected by the light collector.

Abstract: A display device has a drain drive circuit, to which a horizontal output enable signal is applied in synchronization with a horizontal scanning signal. The enable signal allows the horizontal scanning signal to be supplied only to the gates of selected sampling transistors. Gate signal lines are also selected by a gate drive circuit. Accordingly, any set of arbitrary pixel elements in the display device are selected for rewriting the signal retained in the pixel elements.

Abstract: An input digital video signal is allotted by a first multiplexer (310) between regions of a display area to be driven in a dividing manner and is sequentially input to a first memory portion (30A) or a second memory portion (30B). Each of the first and second memory portions (30A and 30B) comprises an input-side line memory (32) composed of, for example, 400-stage input side shift register to which said digital video signal is sequentially input, and an output-side line memory (34) for receiving the data transferred in parallel from the input line memory (32) to serially output the stored data from a selected one of output portions (Out1-4) provided at the 320th, 256th or first stage FF34. The output portion of the memory (34) is thus selected by selectors (380A, 380B) in accordance with the number of pixels in the horizontal direction of the LCD panel, such that LCD panels having the different numbers of pixels can be driven with the same structure.

Abstract: In a display device, under a analog display mode, an analog image signal amplified by an analog amplifier is outputted to a liquid crystal display panel. Under an digital display mode, after being processed by a signal processing circuit, the digital image signal is outputted to the liquid crystal display panel through a DA converter and an amplifier. For writing a “white” image signal, the signal processing circuit converts the input digital signal so that all bits of the signal are a “1.” Also, for writing a “black” image signal, the signal processing circuit converts the input digital signal so that all bits of the signal are a “0.

Abstract: The supply voltage to a driving circuit (100) and LCD (200) generated by a power supply circuit (350) is controlled to be periodically turned on and off during a power save mode, using a timer circuit (260) or timer such as a counting circuit. In this manner, during the power save mode, the power consumption can be reduced by turning off the power supply, and, at the same time, the display can be periodically shown without any further manipulation. By suspending the output of the gate selection signals to the display panels before the control to turn off the power supply, the display immediately before the turn off operation can be maintained even after the power supply is turned off.

Abstract: 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 configure 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.

Abstract: RGB display data is sequentially divided and written into pixels of each of the RGB in a display device. The display device has a DA converter selecting and outputting one of plurality of the &ggr;-correction voltages based on the sequentially divided RGB display data, the &ggr;-correction voltage switching circuit selecting the &ggr;-correction voltage for each of the RGB by changing the first and second reference voltages for each of the RGB, and the switching circuit selectively supplying the output of the DA converter to the pixels of each of the RGB. The &ggr;-correction is individually performed for each of the RGB. The individual &ggr;-correction for each of the RGB can improve the reproducibility of colors without enlarging the circuit size.

Abstract: 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.

Abstract: 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.

Abstract: The active matrix display device of this invention operates under two operation modes: a normal operation mode in which the pixel element electrode sequentially receives the pixel element voltage in response to an image signal sequentially inputted and a memory operation mode in which display is made based on the data held by the retaining circuit. In this active matrix display device, at least a part of the retaining circuit is set for the predetermined voltage and functions as a storage capacitance element for holding the voltage between the pixel element electrode and the common electrode under the normal operation mode. In this configuration, it is possible to reduce the size of the storage capacitance element originally disposed, because at least a part of the retaining circuit works as the storage capacitance element. Therefore, as the size of the storage capacitance element gets smaller, the size of the pixel element can also be smaller, leading to the size reduction of the device as a whole.