Abstract: Systems, apparatuses, and methods are described for determining a direction associated with a detected spoken keyword, forming an acoustic beam in the determined direction, and listening for subsequent speech using the acoustic beam in the determined direction.

Abstract: A LED based lighting apparatus is disclosed. The light engine used in the lighting apparatus may use printed circuit board and have a plurality of LED groups that are independently controllable by a control unit. The power supply input and return paths connected to each LED group may be implemented on different layers to allow a compact footprint that may be used with traditional fluorescent encasements with relatively little modification. The LEDs may comprise a subset of LEDs having a first colour and a subset of LEDs having a second colour different from said first colour intertwined on the light engine.

Abstract: A display device for a musical instrument includes a touch panel and a switcher. The touch panel is placed to be adjacent to an exterior member that constitutes appearance of the musical instrument. The switcher switches appearance of the touch panel between a first mode and a second mode in which the appearance of the touch panel is closer to appearance of the exterior member than in the first mode.

Abstract: A display apparatus includes a display panel, a gate driver, a data driver and an emission driver. The display panel includes a pixel. The gate driver outputs a data write gate signal having a corresponding active level and a data initialization gate signal having a corresponding active level to the pixel in a writing frame, outputs the data write gate signal not having the corresponding active level and the data initialization gate signal not having the corresponding active level to the pixel in a holding frame and outputs the data write gate signal having the corresponding active level and the data initialization gate signal not having the corresponding active level to the pixel in a writing compensation frame. The data driver outputs a data voltage to the pixel. The emission driver outputs an emission signal to the pixel.

Abstract: A display device includes: sub-pixels each including a memory block including memories; memory selection line groups each including memory selection lines electrically coupled to the memory blocks in the sub-pixels that belong to the corresponding row; a memory selection circuit configured to concurrently output memory selection signals to the memory selection line groups; a potential line; a conduction switch provided for at least one memory in the memory block on a one-to-one basis; and an operating-memory conduction circuit configured to output, to the conduction switch, an operation signal for determining whether to electrically couple or uncouple the potential line and the corresponding one memory. Each memory is capable of storing sub-pixel data therein when being coupled to the potential line. Each sub-pixel displays an image based on the sub-pixel data stored in one memory in the sub-pixel according to the memory selection line supplied with the memory selection signal.

Abstract: A projection device, a light source system and a projection method thereof are provided. A portion of the light-emitting units are controlled to provide a light beam as the first light beam. It is detected whether characteristic parameters of the light-emitting units providing the light beam reach a preset value. When the preset value is not reached, the light-emitting units providing the light beam are disabled, and the remaining light-emitting units are controlled to provide the back-up light beam as the first light beam. A portion of the first light beam is converted into a second light beam. The first light beam of which the wavelength is not converted and the second light beam are combined to generate an illumination beam. The illumination beam is converted into an image beam. The image beam is converted into a projection beam.

Abstract: A monitor device is provided for monitoring a lighting arrangement of lighting elements of unknown electrical load, and a driver using the monitoring arrangement. A set of duty cycles is applied to switches which control sub-sets of lighting elements thereby to create a desired light output. With this desired duty cycle setting, the current for an individual duty cycle period is monitored, in particular to detect variations in a current plateau level 5 within the individual duty cycle period. This is used to determine a power consumption of the lighting arrangement and to adjust the duty cycles as a function of the detected current. This avoids the need to probe the sub-sets of lighting elements individually in order to determine the nature of the load and its power consumption.

Abstract: A signal strength meter/indicator for use with an over-the-air broadcast television signal receiving antenna includes an input bandpass filter circuit, a first preamplifier circuit, a controllable variable attenuator circuit, a second preamplifier circuit, a splitter, an output bandpass filter circuit, a VHF/UHF filter circuit, a power detector circuit, a microcontroller and a display. The microcontroller, the controllable variable attenuator circuit, the second preamplifier circuit, the splitter, the VHF/UHF filter circuit and the power detector circuit together define an AGC circuit which adjustably controls the power level of an output signal provided to a television.

Abstract: Provided is a photoelectric sensor capable of enhancing display flexibility of a display section mounted on the photoelectric sensor and making this display flexibility contribute to improvement in user's operability. In a Run mode, a current value is displayed in large-sized numerals on a display section. When switching is made from the Run mode to a setting mode and letter information is to be displayed in the setting mode, a current value is displayed in relatively small-sized numerals at the corner (e.g., lower left) of the display section.

Abstract: A display device includes: a plurality of sub-pixels each including a memory block that includes a plurality of memories each of which is configured to store sub-pixel data; a plurality of memory selection line groups provided to respective rows and each including a plurality of memory selection lines electrically coupled to the corresponding memory blocks in the sub-pixels that belong to a corresponding row; a memory selection circuit configured to simultaneously output a memory selection signal to the memory selection line groups, the memory selection signal being a signal for selecting one from the plurality of memories in each of the memory blocks. In accordance with the memory selection lines supplied with the memory selection signal, the sub-pixels display an image based on the sub-pixel data stored in memories in the respective sub-pixels, the memories each being one of the plurality of memories in the corresponding sub-pixel.

Abstract: An electro-optical device includes a pixel circuit provided to correspond to an intersection of a scan line and a data line, a low potential line, and a high potential line. The pixel circuit includes a light emitting element, a first transistor, and a memory circuit including a first inverter, a second inverter, and a second transistor. The first transistor is disposed between an first input terminal of the first inverter and the data line. The second transistor is disposed between an second output terminal of the second inverter and the first input terminal. An first output terminal of the first inverter is electrically connected to an second input terminal of the second inverter. When the first transistor is in an ON-state, the second transistor is in an OFF-state.

Abstract: An electro-optical device includes a first scan line, a data line, and a pixel circuit provided at a position corresponding to intersections of the first scan line and the data line. The pixel circuit includes a light emitting element, a memory circuit, a first transistor, and a second transistor. The first transistor is electrically connected in series to the light emitting element, and a gate of the first transistor is electrically connected to the memory circuit. The second transistor is disposed between the data line and an input of a first inverter. The third transistor is disposed between an output terminal of a second inverter and the input of the first inverter. When the second transistor turns from an OFF-state to an ON-state, the third transistor is not in an ON-state.

Abstract: An electro-optical device includes a pixel circuit located at a position corresponding to an intersection of a scan line and a data line, a low potential line, and a high potential line. The pixel circuit includes a light emitting element, a first transistor, a memory circuit including a first inverter, a second inverter, and a second transistor, and a third transistor. The first transistor is disposed between an input of the first inverter and the data line. The second transistor is disposed between an output of the second inverter and the input. The third transistor and the light emitting element are disposed between the low potential line and the memory circuit. When the first transistor is in an ON-state, the second transistor and the third transistor are in an OFF-state.

Abstract: A local dimming system includes a mean estimation unit that estimates a mean value of an image; a PWM gain control unit that generates a PWM gain value according to the mean value; a spatial filter that performs on a plurality of the mean values in spatial domain to enhance a plurality of the PWM gain values, thereby generating enhanced PWM gain values; a scene change detection unit that detects scene change according to a histogram mean value generated by the mean estimation unit; a temporal filter that performs in temporal domain according to the enhanced PWM gain values and a result of scene change detection, thereby generating PWM values; a light shape imitation (LSI) unit that generates luminance gain according to the PWM value; and a pixel compensation unit that performs pixel compensation on the image according to the luminance gain, thereby resulting in a compensated image.

Abstract: A pixel circuit, a display panel, a display device and a driving method are disclosed. The pixel circuit includes: a light-emitting circuit including a plurality of light-emitting sub-circuits (111); and a compensation driving circuit including an output terminal and a driving transistor. The plurality of light-emitting sub-circuits are all electrically connected to the output terminal; and the compensation driving circuit is configured to receive a light-emitting data signal, compensate for a threshold voltage of the driving transistor, and drive any one of the plurality of light-emitting sub-circuits to emit light according to an output signal output by the output terminal.

Abstract: A control unit for a LED assembly includes a first and second LED unit, the LED units being serial connected. The LED assembly, in use, is powered by a switched mode power supply. The control unit being arranged to receive an input signal representing a desired output characteristic of the LED assembly, determine a first and second duty cycle for respective LED units associated with a nominal current of the switched mode power supply, for providing the desired output characteristic, determine the largest of the first and second duty cycles for respective LED units, determine a reduced current based on at least the largest of the duty cycles, adjust the first and second duty cycle for respective LED units based on the reduced current, and provide an output signal for the LED assembly and the switched mode power supply based on the adjusted first and second duty cycles and the reduced current for obtaining the desired characteristic.

Abstract: A display apparatus includes a first pixel, a second pixel, a light sensor, and a light shield. The first pixel has a first light-emitting device which includes a first emission layer that emits light in a first wavelength band in a first direction. The second pixel has a second light-emitting device which includes a second emission layer to emit light in a second wavelength band in a second direction different from the first direction. The second emission layer is below the first emission layer of the first light-emitting device. The light sensor senses light in the second wavelength band emitted from the second pixel and reflected by an object. The light shield is arranged along a light path incident to the light sensor.

Abstract: The present invention relates to an illumination control method and system for LED lamps, where the system comprises: a receiver module (1) configured to obtain a number of illumination levels (N) indicative of the light resolution of a LED lamp (6) and a duty cycle (D) associated with a desired light intensity for a LED lamp (6), a control module (2) comprising a control unit (7) configured to: generate a periodic signal with a period (T) and a duty cycle from the number of illumination levels (N) and the duty cycle (D), generate an illumination control signal (SCi) from the periodic signal for controlling the power supply of at least one LED lamp (6), and a power supply module (3) configured to power at least one LED lamp (6) according to the illumination control signal (SCi).

Abstract: Systems and methods of color data driving for light emissive visual display technology, and particularly to systems and methods for driving pixels with more than three primary color subpixels. Only a subset of the total number of subpixels per pixel are driven at any one time reducing the number of decoders/DACs. The decoders/DACs are coupled by a color decoder only to the active subpixels using a switching fabric.

Abstract: This disclosure provides systems, methods and apparatus for providing illumination. In one aspect, an etendue preserving optical coupling system configured to: receive incident light through an input aperture; and emit the incident light through an output aperture having an area smaller than an area of the input aperture is provided. The light output from the optical coupling system is coupled into a light receiving system including material having substantially the same refractive index as the refractive index of the material of the optical coupling system. The light receiving system includes a light guide configured to internally propagate the redirected light and to release light to illuminate the ambient environment.

Abstract: A dynamic random access memory includes a main body which has a substrate portion and a light-emitting portion and a transmission port, the substrate portion includes a board and a first coating layer, the board has a light-transmittable portion and a first face, the first coating layer is coated on the first face and has an emergent light-transmittable portion corresponding to the light-transmittable portion, and the substrate portion has a memory module. The transmission port is disposed on the substrate portion and electrically connected with the memory module. The electronic device includes the dynamic random access memory and further includes a shell portion. The shell portion is covered on two opposite lateral faces of the dynamic random access memory and at least shields the light-emitting portion, and the shell portion further has a second light-transmittable portion corresponding to the emergent light-transmittable portion.

Abstract: The invention relates to a power supply device (3) for supplying power to an electrical consumer (2) having a variable power consumption in a power distribution system (1), particularly in a DC power distribution system for lighting applications, wherein the power supply device (3) is output current controlled and is adapted to provide the output current depending on the power consumed by the electrical consumer (2). Since the output current is not constant, but controlled depending on the power consumed by the electrical consumer (2) being preferentially a lamp, the output current can be adapted to the actually consumed power, thereby allowing for an improved efficiency of distributing the power in the power distribution system (1). In particular, if less power is consumed by the electrical consumer (2), a lower output current can be provided, thereby reducing losses in cables and electrical connectors of the power distribution system.

Abstract: A ray of light 2 enters vertically to an incident surface 5a of a rod integrator 5, while another ray of light 4 enters obliquely to the incident surface 5a of the rod integrator 5. As a result, the outermost spread angle of the ray of light 4 after entering the rod integrator 5 coincides the outermost spread angle of the ray of light 2 after entering the rod integrator 5.

Abstract: A motor vehicle includes a control device and at least one lighting device which is controllable by the control device sequentially in at least two modes which illuminate surroundings of the vehicle differently. At least one camera captures at least two images of the differently illuminated surroundings of the vehicle. The at least two different images are processed by an image processing device for producing a processing result which is transmitted for control of a driver assistance system.

Abstract: A front-end lighting system for projection includes: a RGB three-color LED light source, configured to generate three monochromatic lights; a reflector, configured to perform a first light mixing operation on three monochromatic lights generated by the RGB three-color LED light source; a first group of relay lenses, configured to adjust a light path; and a compound eye field lens, configured to perform a second light mixing operation on the three monochromatic lights generated by the RGB three-color LED light source. The reflector includes a reflecting surface, and three monochromatic lights emitted by the RGB three-color LED light sources, after being reflected by the reflecting surface of the reflector, pass through the first group of relay lenses and the compound eye field lens in sequence.

Abstract: An illumination module includes a light source to output lamp light and a mixing light guide having a substantially rectangular cross-section. The mixing light guide includes a spatial homogenization section and an emission section. The spatial homogenization section includes a first end coupled to receive the lamp light having a first cross-section profile from the light source and a second end to deliver the lamp light with a second cross-section profile substantially conforming to the substantially rectangular cross-section of the mixing light guide. The emission section is adjacent to the second end. The emission section includes an emission surface through which the lamp light is emitted with a substantially uniform intensity profile. The emission surface faces a different direction than an input surface of the first end through which the lamp light is received into the mixing light guide.

Abstract: An LED driving method is provided. The method includes the steps of: receiving a brightness control signal, wherein the brightness control signal represents a duty cycle of an LED within a pulse width modulation cycle, and the duty cycle is indicated by a plurality of illuminating clocks; dividing the PWM cycle into a plurality of sub-PWM cycles; and equally distributing the illuminating clocks to each of the sub-PWM cycles.

Abstract: A thin film transistor (TFT) that includes a control electrode, a semiconductor pattern, a first input electrode, a second input electrode, and an output electrode is disclosed. in one aspect, the semiconductor pattern includes a first input area, a second input area, a channel area, and an output area. The channel area is formed between the first input area and the output area and overlapped with the control electrode to be insulated from the control electrode. The second input area is formed between the first input area and the channel area and doped with a doping concentration different from a doping concentration of the first input areas. The second input electrode makes contact with the second input area and receives a control voltage to control a threshold voltage.

Abstract: According to one embodiment, a display device includes a first insulating layer, a second insulating layer, a pixel electrode, a light emitting layer, an opposite electrode and a pixel circuit. The second insulating layer is provided on the first insulating layer. The pixel electrode is provided on the second insulating layer and light-transmissive. The light emitting layer is provided on the pixel electrode. The opposite electrode is provided on the light emitting layer. The circuit is provided between the first insulating layer and the second insulating layer, includes an interconnect supplied with a drive current, and is configured to supply the drive current to the pixel electrode. The circuit is connected to the pixel electrode. The interconnect has a first region overlaying the pixel electrode when projected onto a plane parallel to the first insulating layer. The interconnect has an opening in the first region.

Abstract: A display device includes a display panel, a driving circuit, and a connection terminal. The display panel includes a display area and a non-display area surrounding the display area and an electrode terminal disposed in the non-display area and extended in a direction. The driving circuit includes a signal terminal extended in the same direction as the electrode terminal and disposed adjacent to the electrode terminal. The connection terminal is disposed on the electrode terminal and the signal terminal to electrically connect the electrode terminal and the signal terminal.

Abstract: A light emitting system includes a light emitting device having a forward voltage, and an optical power control device. The optical power control device includes a control signal module and a current controller. The control signal module generates a control signal according to the forward voltage, and the current controller permits flow of a driving current through the light emitting device according to the control signal.

Abstract: A display that includes energy sensors within the display itself is disclosed. An Organic Light Emitting Diode (OLED) can be made to operate both as a light emitter and as an energy detector. When forward biased with an appropriate driving signal, the OLED emits light via electroluminescence, which can be used to make a portion of an image on the display. In another mode, the OLED can detect energy by converting incoming photons or energy into an electrical signal by the photoelectric effect. By operating OLEDs in the display in both emissive and sensing modes, energy that shines on the display, such as from an outside source can be detected at the same time an image is shown. Additionally, a display including OLEDs can detect light energy generated by the display itself.

Abstract: The invention relates to an LED electronic sign board capable of power-saving per pixel line, comprising: an LED display panel; a panel driver; a switching mode power supply that receives AC power, generates driving power required to operate the LED display panel and the panel driver and supplies power to the LED display panel and the panel driver; a black line extractor that analyzes an image signal which will be displayed on the LED display panel and extracts pixel lines which becomes black per LED module; and a main controller that controls the panel driver to display an image on the LED display panel according to the image signal, and that controls a switching signal for the operation of the switching mode power supply to shut off driving power that is supplied to the pixel lines extracted by the black line extractor from the switching mode power supply.

Abstract: The present invention provides an organic light emitting diode touch display panel including a substrate, a plurality of first electrodes and a plurality of second electrodes disposed on the substrate, a plurality of light emitting layers, a plurality of dielectric layers, a plurality of first electrode stripes, and a plurality of second stripes. Each light emitting layer is disposed on each first electrode, and each dielectric layer is disposed on each second electrode. Each first electrode stripe is disposed on the light emitting layers in each row, and each second electrode stripe is disposed on the dielectric layers in each row. Each first electrode, each light emitting layer and each first electrode stripe form an organic light emitting diode, and each second electrode, each dielectric layer and each second electrode stripe form a touch sensing capacitor.

Abstract: A light emitting diode (LED) driving circuit preventing light leakage issue. The LED driving circuit comprises an LED driver, a driving circuit module and a power supply. When an input voltage is much higher, a high frequency pulse width modulation signal is set to a low level to avoid a light leakage of the LED by turning off a metal oxide semiconductor field effect transistor (MOSFET), such that the input voltage is not limited by the light leakage of the LED. As a result, the input voltage can be increased sufficiently for further reducing a switching loss effectively.

Abstract: A device that may be used as a multi-color pixel is provided. The device has a first organic light emitting device, a second organic light emitting device, a third organic light emitting device, and a fourth organic light emitting device. The device may be a pixel of a display having four sub-pixels. The first device may emit red light, the second device may emit green light, the third device may emit light blue light and the fourth device may emit deep blue light. A method of displaying an image on such a display is also provided, where the image signal may be in a format designed for use with a three sub-pixel architecture, and the method involves conversion to a format usable with the four sub-pixel architecture.

Abstract: Disclosed is a power control device, which generates PWM signals corresponding to obtained voltage signals, and which performs PWM control of power to be supplied to a load. The power control device is provided with a sampling section that performs sampling of the voltage signals, and a duty factor updating section, which updates the duty factor of the PWM signals on the basis of the sampling results. The sampling section is prevented from performing sampling during a masking period which is set as the on-period or the off-period of the PWM signals.

Abstract: A circuit substrate including a base layer and a plurality of lead units arranged as an array is provided, wherein the base layer has a plurality of through grooves, and the lead units are disposed on the base layer. Each of the lead units includes a common terminal and at least three leads. The common terminal is capable of being divided into a plurality of electrodes connected with each other. The leads are extended outwards from the edge of the common terminal, and each of the leads is extended outwards from the edge of one of the electrodes. The through grooves expose the common terminals of the lead units.

Abstract: An organic light emitting diode (OLED) display includes: a switching thin film transistor including a switching gate electrode, a switching active layer, a switching source electrode, and a switching drain electrode; a driving thin film transistor including a driving gate electrode, a driving active layer, a driving source electrode, and a driving drain electrode; a capacitor including a first capacitor electrode and a second capacitor electrode; a scan line that is connected to the switching gate electrode of the switching thin film transistor; a data line that intersects the scan line and that is connected to the switching source electrode of the switching thin film transistor; a first power source line that is parallel to the data line and that is connected to the driving source electrode of the driving thin film transistor; a second power source line that is separated parallel to the data line and that is connected to the second capacitor electrode of the capacitor; and an organic light emitting diode tha

Abstract: A document recognition system and method, where images are represented as a collection of primitive features whose spatial relations are represented as a graph. Useful subsets of all the possible subgraphs representing different portions of images are represented over a corpus of many images. The data structure is a lattice of subgraphs, and algorithms are provided means to build and use the graph lattice efficiently and effectively.

Abstract: A computer including a microprocessor, a memory system, a bus system, and a single point indicator. The memory system includes an operating system stored therein. The bus system couples the memory system to the microprocessor. The single point indicator is coupled to the microprocessor and is capable of emitting a single point of light of substantially any wavelength in a visible spectrum. The computer also includes logic that determines a level of a selected operational parameter of the computer and logic that generates a corresponding wavelength of light emitted from the single point indicator. The corresponding wavelength of light corresponds to the level of the selected operational parameter. A method for indicating a level of a selected operational parameter of a computer is also disclosed.

Abstract: An apparatus includes a circuit branch electrically connected to a voltage rail and including a light emitting device connected in series with a drain of a dual gate transistor, a switching transistor configured to apply a data voltage to a first gate of the dual gate transistor in response to a scan signal, a capacitor connected between the first gate of the dual gate transistor and the drain of the dual gate transistor, and a conductor for supplying a control voltage to a second gate of the dual gate transistor. A method of operating the circuit is also described.

Abstract: A display for an ice rink, comprising a first layer of ice within a peripheral boundary of the ice rink. An array of hermetically sealed, multiple individual organic light emitting diodes are positioned within the peripheral boundary on top of the first layer of ice. A second layer of ice on top of the array has an internal side facing the array and an external surface on a side opposite the internal side. A power source operatively connected to the array provides power to the individual organic light emitting diodes in the array. The multiple individual organic light emitting diodes are selectively controllable such that graphic images can be displayed by using specific organic light emitting diodes selected from among the individual organic light emitting diodes in the array and the graphic images will be visible through the external surface of the second layer of ice.

Abstract: Systems and methods for realizing display drivers, especially OLED drivers having a high efficiency. With a single pass, using an algorithm based on simple equations based on gathered maximum display data, the driver can split an image to be displayed into multiple planes and tiles thus balancing peak current consumption. Furthermore the driver is able to optimize drive time periods in regard of many parameters.

Abstract: A light display is mounted on the spokes of a rotating bicycle wheel. The display includes a plurality of individual arrays of lights forming a set. The set of arrays are attached together into a single rigid light display apparatus attached to a spoke of the wheel at the tip of each array of lights. At least one sensors on the apparatus, senses the angular velocity and angular position of the rotating wheel. A microprocessor, is mounted on one of the arrays of lights and connected to the sensor, and is further connected to a shared electrical bus which traverses every array of lights. The shared electrical bus is formed by the electrical connection of all the arrays of lights in a line or loop topology. Each array of lights has at most two connection points to the shared electrical bus. The microprocessor modulates the plurality of arrays of lights via the shared electrical bus and without a direct connection to every array of lights.

Abstract: A display device including a display unit including first and second lines, light emitting elements and pixel circuits; a first drive unit sequentially applying a selection pulse to the first lines; and a second drive unit applying a signal pulse including first to third voltages to each of the second lines. Each of the pixel circuits includes a first transistor sampling the signal pulse, and a second transistor driving one of the light emitting elements. The first drive unit applies the selection pulse when the first voltage is being applied by the second drive unit, before a correction of a threshold voltage of the second transistor is initiated and within a period that the one of the light emitting elements is being turned out, and the first drive unit applies the selection pulse when the second voltage is being applied by the second drive unit.

Abstract: Representative embodiments of the disclosure provide a system and apparatus for controlling an intensity and spectrum of light emitted from a solid state lighting system. The solid state lighting system has a first emitted spectrum at full intensity and at a selected temperature, with a first electrical biasing for the solid state lighting system producing a first wavelength shift, and a second electrical biasing for the solid state lighting system producing a second, opposing wavelength shift. Representative embodiments provide for receiving information designating a selected intensity level and a selected temperature and providing a combined first electrical biasing and second electrical biasing to the solid state lighting system to generate emitted light having the selected intensity level and having a second emitted spectrum within a predetermined variance of the first emitted spectrum over a predetermined range of temperatures.

Abstract: The present invention is to provide an LCD unit, an LCD apparatus, and a method of setting a drive voltage of the LCD unit with a simple operation. The LCD unit includes a label pasted on a place of the LCD unit, wherein the label includes an information code, which is information-coded from a data of a drive voltage for achieving the best contrast in optical characteristics of the LCD unit. The best drive voltage to drive the LCD unit with the best contrast is thereby easily set.

Abstract: An organic light emitting display device includes a scan driver for supplying a first scan signal to a first scan line during a first period and a second period, a second scan signal to a second scan line during the second period, and a light emitting control signal to a light emitting control line during a period at least spanning the first and second periods. A data driver sequentially supplies data signals to an output line during the first period. A demultiplexer is electrically coupled to the output line, receives the data signals and supplies the data signals to data lines which are connected to pixels. Each pixel receives one of the data signals during the first period, compensates a threshold voltage of a driving transistor during the second period, and generates light with a brightness corresponding to the one of the data signals after the second period.

Abstract: A voltage equal to the threshold value of a TFT (106) is held in capacitor unit (109). When a video signal is inputted from a source signal line, the voltage held in the capacitor unit is added thereto and a resultant signal is applied to a gate electrode of the TFT (106). Even when a threshold value is varied for each pixel, each threshold value is held in the capacitor unit (109) for each pixel. Thus, the influence of a variation in threshold value can be eliminated. Further, holding of the threshold value is conducted by only the capacitor unit (109) and a charge does not move at writing of a video signal so that a voltage between both electrodes is not changed. Thus, it is not influenced by a variation in capacitance value.