Abstract: A device for inspecting an organic light-emitting display apparatus includes a power supply unit, a power receiving unit, a wiring location sensing unit, and a control unit. The power supply unit applies an AC signal to each of wirings arranged in the organic light-emitting display apparatus. The power receiving unit senses an electrical signal from each of the wirings. The wiring location sensing unit senses a location of each of the wirings. The control unit determines whether each of the wirings has a defect based on the sensed electrical signal and information pertaining to each wiring type of the wirings.

Abstract: A display apparatus is provided. The display apparatus includes a substrate, a display panel on the substrate, and an encapsulation film sealing the display panel. The encapsulation film includes at least one organic layer and/or at least one inorganic layer and at least one pair of conductive layers.

Abstract: A system, apparatus and method for light diffusion and testing fixtures. The system includes remote derangement controls to test the operation of a battery backup system associated with a fixture. The light fixture may incorporate light diffusion features including back mounted light sources, channeled corners in a translucent material and/or pitted surfaces of a translucent material. The system may further include remote monitoring elements and/or sensors to evaluate proper operation of the light diffusion characteristics of a fixture during operation of the battery backup system.

Abstract: A new portable, self-contained device for testing the full cycle of trailer light modes without additional manual actuation by the user and for identifying where and what type of specific error occurred, if any are detected. The inventive device generally comprises a compact portable housing with a fixedly attached handle and a removable housing top. Within the compact portable housing is a self-contained, rechargeable 12 volt power source to power all functionality over a sustained period of time. Also within the compact portable housing is a light mode control means that allows the device to cycle through multiple light modes for testing, and an error detection analysis means that indicates where and what type of fault is detected.

Abstract: An apparatus to measure and collect data relating to properties of light for a plurality of light-producing devices comprises a rail having a longitudinal axis along which the plurality of light-producing devices is aligned. A measurement tool is mounted on the rail and moved under motor control to measure the data for each of the plurality of light-producing devices.

Abstract: The present disclosure provides a detection circuit for a display panel, comprising: a shorting bar, with connection lines for introducing a test signal or a control signal arranged thereon; a transistor array, the gates of which are connected to the connection lines for introducing the control signal, wherein the connection lines for introducing the test signal are connected with the data lines or the scanning lines of the display panel via the sources and the drains of transistors, under the control signal, and a component, arranged between the gates of the transistor array and the shorting bar, for further reducing or increasing a voltage or current of the gates so that the transistor array can be cut off reliably when the control signal is a signal enabling the transistor array to be cut off. The detection circuit can further reduce the channel length of the thus being advantageous for the design of the narrow frame.

Abstract: The disclosure provides a system and method for multi-functional online testing of semiconductor light-emitting devices or modules. The system comprises an electrical characteristic generating and testing equipment, one or more optical characteristic detecting and controlling equipments, an optical signal processing and analyzing equipment, one or more thermal characteristic detecting equipments, a central monitoring and processing computer, a multi-channel integrated drive controlling equipment, one or more multi-stress accelerated degradation controlling equipments, and one or more load boards. The present disclosure enables in-situ online monitoring and testing under accelerated degradation in a multi-stress accelerated degradation environment.

Abstract: In an emergency lighting apparatus, charging efficiency is increased by individually charging cells in a power storage unit. When a power failure or other situation occurs requiring the actual use of the emergency lighting device, the proper operation of the emergency lighting device is ensured. In particular, the disadvantage of additional wiring in a bulb-type lighting fixture and the disadvantage of grounding are addressed so that power can be continuously supplied to the emergency lighting device and the emergency lighting device functions properly.

Abstract: A nest (1) comprising, a fix part (3), and a movable part (5), wherein the fix (part 3) and movable part (5) are configured to cooperate so as to define a (pocket 7) which can receive at least a part of an electrical component (25), wherein the movable part (5) is moveable between a first position and a second position, wherein in the first position the pocket (7) is open so that at least part of the electrical component can be moved into the pocket (7), and in the second position the pocket (7) is closed so that the at least part of the electrical component (25) positioned in the pocket is secured within the pocket, wherein the nest (1) further comprises a biasing means (9) which is arranged to bias the movable part (5) towards its second position. There is further provided a nest assembly, a component handling assembly, and a table comprising said nest.

Abstract: Methods and systems to provide baseline measurements for aging compensation for a display device are disclosed. An example display system has a plurality of active pixels and a reference pixel. Common input signals are provided to the reference pixel and the plurality of active pixels. The outputs of the reference pixel is measured and compared to the output of the active pixels to determine aging effects. The display system may also be tested applying a first known reference current to a current comparator with a second variable reference current and the output of a device under test such as one of the pixels. The variable reference current is adjusted until the second current and the output of the device under test is equivalent of the first current. The resulting current of the device under test is stored in a look up table for a baseline for aging measurements during the display system operation.

Abstract: A test system and a method for testing a backlight unit of an electronic device are provided. The test system includes a selection unit, a backlight control unit, a display control unit, a determination unit and a count unit. The selection unit selects one mode of a number of modes and issues a command. The backlight control unit controls the backlight unit to adjust a luminous intensity. The display control unit controls the display unit to display a selection dialog window showing a number of options corresponding to the number of modes, and the options are displayed in random order. When an option is chosen, the determination unit determines whether the actual change of the luminous intensity of the backlight unit matches the command. The count unit counts a first counting value and a second counting value and determines whether the backlight unit is qualified.

Abstract: Techniques are disclosed for assessing the conditions of LEDs and power supplies of solid state lighting systems. The techniques can be used, for example, to measure the capacitance of an output capacitor C in a switch-mode power supply (SMPS), and to measure the condition of the LEDs being driven by that power supply. In some cases, this assessment can be implemented in a lighting controller that controls the lighting system, which may be configured to simultaneously determine C and the conditions of LEDs. In one example case, the techniques can be implemented, for instance, in a micro-controller operating the lighting system. A lighting system implementing the techniques can be periodically assessed so as to provide real-time diagnostic capability. Numerous example embodiments of SMPS LED lighting systems will be apparent in light of this disclosure.

Abstract: The present disclosure is directed to a method for detecting a failure in a signal light. In one embodiment, the method includes monitoring operation of one or more light emitting diodes (LEDs) of the signal light coupled to a constant current driver, detecting a short circuit in at least one of the one or more LEDs and signaling a failure in the signal light when the short circuit is detected.

Abstract: A current controlling circuit comprises a DC power source, an inductor, a N-channel Metal Oxide Semiconductor (NMOS), one or more LEDs connected in series, a first resistor and a switching arrangement. The positive terminal of the DC power source is connected to the inductor in series. The series of LED is connected in series with the inductor and the first resistor. According to an embodiment the switching arrangement comprises a second resistor, a first switch and a second switch. The second resistor is connected in series with the second switch and connected in parallel with the first switch. The switching arrangement is connected in series with the first resistor and the negative terminal of the DC supply.

Abstract: An organic light-emitting display panel includes a pixel unit connected to a plurality of scanning lines and a plurality of data lines, and including a plurality of pixels, a panel test unit connected to first ends of the plurality of data lines, and configured to output a panel test signal for testing the plurality of pixels, a plurality of data pads connected to second ends of the plurality of data lines, and an array test unit configured to selectively apply a plurality of array test signals to a pixel column of the pixel unit according to a plurality of array test control signals, and detect a signal output from the pixel column to which the plurality of array test signals are applied.

Abstract: Provided is an organic light emitting display panel. The organic light emitting display panel includes a pixel unit including a plurality of pixels I displaying mutually different colors, a plurality of data pads electrically connected to wirings extending from the data lines, each of the plurality of data pads being connected to corresponding data lines, respectively, and an array test unit applying an array test signal to the plurality of pixels of the pixel unit, and sensing a current outputted from the plurality of pixels. The array test unit includes an array test pad electrically connected to a plurality of data pads through a plurality of array test switches.

Abstract: A method for testing an array for a pixel circuit of an organic light emitting diode display, which includes a first transistor that transmits a driving current corresponding to a data signal to an organic light emitting diode according to a scan signal and at least one capacitor, uses an array test device having a control device and a driver. The method includes performing a first irradiation of electron beams to an exposed portion of a first electrode of the at least one capacitor before manufacturing of the organic light emitting diode is completed, calibrating the control device of the array test device based on secondary electrons output by the at least one capacitor, performing a second irradiation of electron beams to an anode of the pixel circuit, and detecting whether the first transistor is normally operated based on an output amount of secondary electrons output by the anode.

Abstract: An apparatus for inspecting a light emitting diode (LED) package is provided to inspect an LED to determine whether or not it is defective, and discard the LED when the LED is defective. The apparatus for inspecting an LED package includes: an inspection unit inspecting an LED through a visual inspection to determine whether or not the LED is defective; and a defective product rejection unit discarding the LED when the LED is determined to be defective on the basis of inspection results from the inspection unit among LEDs supplied from the inspection unit. Because the operation of inspecting LEDs and discarding a defective LED are automated and can be rapidly processed as a sequential process, productivity can be improved.

Abstract: Systems, methods, and devices are provided for detecting short circuits in a backlight assembly without a resistor-based current sensor. For example, an electronic display according to the present disclosure may include a display panel and a backlight assembly to illuminate the display panel. The backlight assembly may drive a backlight element to illuminate the display panel and may include backlight short-circuit detection circuitry. The backlight short-circuit protection circuitry may detect a feedback voltage associated with the backlight element and determine when a short circuit has occurred based at least in part on the feedback voltage.

Abstract: An inspection method including following steps is provided. A pixel array substrate including a plurality of pixel units is in contact with a photoelectric inspection device. A plurality of electrical signals is inputted to the pixel units of the pixel array substrate and the photoelectric inspection device. Based on an optical property of the photoelectric inspection device, the pixel units of the pixel array substrate are being examined on whether they are normal or not. Moreover, an inspection apparatus realizing the inspection method is also provided.

Abstract: A method of testing an organic light-emitting display panel, a mother substrate testing apparatus, and a method of testing a mother substrate are provided. The method of testing an organic light-emitting display panel includes operations of applying an electric field to an encapsulation layer of the organic light-emitting display panel and determining a defect of the organic light-emitting display panel.

Abstract: An electrical assembly and method for detecting failures in an LCD source driver is disclosed herein. A plurality of active channels are placed on the source driver which communicate electronically with an LCD. At least one dummy channel may be placed on the source driver which is driven with an original signal. A microprocessor may then receive the dummy channel and compare the received dummy channel signal to the original signal. An error message may be transmitted when the received dummy channel signal does not match the original signal. Alternatively, the source driver may be provided with a split active channel which is provided with an original signal that is split into an active split channel and a dummy split channel. While the active split channel is sent to the LCD, the dummy split channel is sent to the microprocessor for comparison with the original signal.

Abstract: According to one embodiment, a diagnostic device (8) for identifying a defect in an LED light string includes a probe (18) and a polarity selector switch (16). The LED light string includes a conductor provided within an insulation layer. The probe (18) is configured to penetrate the insulation layer and contact the conductor of an LED light string. The polarity selector switch (16) is electrically coupled to the probe (18) and configured to control the polarity of an electrical waveform provided to the probe (18).

Abstract: A system for determining the efficiency degradation of an organic light emitting device (OLED) in an array-based semiconductor device having an array of pixels that include OLEDs. The system determines the relationship between changes in an electrical operating parameter of the OLEDs and the efficiency degradation of said OLEDs, for at least one stress condition; measures a change in the electrical operating parameter of the OLEDs; determines the stress condition of at least one pixel or group of pixels in the semiconductor device; and uses the determined relationship and the determined stress condition to determine the efficiency degradation of the OLEDs corresponding to the measured change in the electrical operating parameter of the OLEDs.

Abstract: In one embodiment, a circuit arrangement for short-circuit detection in diodes comprises a first terminal (1a,b) for connection to a voltage source (PS), a second terminal (2a, 2b) for connection to a first current sink (CS1) and a third terminal (3) for supplying a potential signal (S1), wherein a first diode string (CH1) can be connected to the voltage source (PS) on the anode side and to the first current sink (CS1) on the cathode side, and wherein the third terminal (3) can be coupled to the cathode side of the first diode string (CH1) by means of a resistor (Rm).

Abstract: This specification relates to a method and a system for detecting light emitting diode (LED) short circuit in a plurality of LED strings or detecting matching among the plurality of LED strings, wherein one end of each of the plurality of LED strings is connected to a same output end of a power supply, and the other end is respectively connected to a corresponding switch. According to the present invention, first current of each of LED strings is obtained when the output end of the power supply outputs a first voltage; differences between the minimum of the first currents of LED strings and other first currents are calculated; the differences are compared with a comparing threshold; it is determined that the LED strings corresponding to the other currents for which differences are larger than the comparing threshold include short circuit or mismatch with the LED string corresponding to the minimum current. Accordingly, it is possible to reduce the number of pins and area of a control chip.

Abstract: An organic electroluminescence device is provided, which comprises: a lighting region, a wiring region, a bonding region and a wiring extending region (300), the lighting region comprises an anode, an organic functional layer, a cathode; the wiring region comprises wirings connecting the anode and cathode with a driving chip or a circuit board; the bonding region is a region in which the wirings connect with the driving chip or the circuit board; the ends of the wirings locate in the wiring extending region, the wirings in the wiring extending region are parallel with the wirings in the wiring region or form an angle with the wirings in the wiring region. A method for testing the organic electroluminescence device is also provided. With improving the wiring arrangement of the organic electroluminescence device, it is easier and more accurate to press bond a conductive adhesive tape and the wirings, and, the row wirings and the column wirings are protected from being shorted during screen testing.

Abstract: The present disclosure relates to a method for manufacturing an EL display apparatus including a light-emitting portion in which a light emitting layer is disposed between a pair of electrodes, a thin film transistor array device for controlling light emission of the light-emitting portion, and an EL display panel in which a plurality of pixels of colors of R, G, and B are disposed. After production of the EL display panel, an inspection step is performed to apply, to each of the pixels, a voltage which is preset for each of the colors of R, G, and B of the pixels, the voltage applied in the inspection step is a potential difference that is a reverse bias voltage opposite to an anode voltage and a cathode voltage during lighting, and the potential difference allows a faulty pixel to turn to a dead dot.

Abstract: Checking failures in transistors including driving transistors, switching transistors, and sampling transistors before light emitting elements are formed in a display device. I-V characteristics including threshold voltage of the driving transistor 10C in one pixel circuit can be detected. In a pixel circuit, the sampling transistor 10A and switching transistor 10D are made conductive and the signal potential is given to the gate electrode of the driving transistor 10C from the signal line DTCm. At this time, the current which flows between the drain electrode and source electrode of driving transistor 10C flows through the switching transistor 10D and a reference potential line Vref_r to a test point, and is measured by a current measuring device connected to the test point.

Abstract: Disclosed herein is a trailer light checking system for a vehicle for checking an electrical connection between the vehicle and a trailer comprising a plurality of exterior vehicle lights, the exterior vehicle lights including a left turn indicator light, a right turn indicator light and a brake indicator light, and further comprises a terminal connection configured to electrically connect each of the plurality of exterior vehicle lights to a respective trailer light. The trailer light checking system also comprises a vehicle controller having a trailer connection checking mode configured to check the terminal connection by simulating manual operation of each of the plurality of exterior vehicle lights according to a timed sequence, such that a respective trailer light will actuate in combination with the simulated manual operation of each of the plurality of exterior vehicle lights if the terminal connection and the respective trailer light are functioning correctly.

Abstract: An organic light emitting display and a driving method thereof, which can effectively detect degradation information of pixels in a display. An organic light emitting display includes a pixel unit and a degradation detector. The pixel unit has a plurality of pixels positioned at intersection portions of scan lines and data lines. The degradation detector divides the pixel unit into a plurality of first blocks each including a plurality of pixels, and detects degradation information for each second block including a plurality of first blocks. In the degradation detector, the second blocks are divided so that each second block shares one or more first blocks with another second block adjacent thereto.

Abstract: The invention relates to the operation of illuminants, in particular OLEDs. The invention relates to a method and a measuring instrument for determining the electrical properties of an OLED, the equivalent circuit diagram of which is composed of the parallel connection of an equivalent diode DE and an equivalent capacitance CE as well as an equivalent resistance RE that is connected in series to said parallel connection. The values for the equivalent resistance RE and the equivalent capacitance CE are determined at a different time than are the values for the equivalent diode DE.

Abstract: The present invention provides an LED lighting device and a method for verifying the device's lifespan. The LED lighting device includes multiple LED light sources, a controller configured to keep time for the LED lighting device's lifespan; a low voltage DC power source configured to supply power; a light intensity sensor configured to capture illuminance data; and a display terminal configured to display received data. Further, the controller records time keeping data based on the illuminance data captured by the light intensity sensor and sends the time keeping data to be displayed on the display terminal.

Abstract: A method and system of classifying predicted performance of HID lamps or light sources. A characteristic of each lamp or light source is measured after a relatively short time of operation of the lamp or light source. The measurement is placed into one of a plurality of classifications based on its relative value to other similar measurements. Each class is correlated to long term predicted performance of the lamp or light source.

Abstract: An inspection system is provided, which applies a forward or reverse voltage on a light-emitting device and measures a current thereof respectively before and after temperature rise, and determines whether the device fails according to the fact whether a current difference before and after the temperature rise is larger than a failure current determination value. Alternatively, the inspection system adopts a current applying device to apply a forward and reverse current on a light-emitting device and measures a voltage difference thereof respectively before and after temperature rise, and determines whether the device fails according to the fact whether a difference of the voltage differences before and after the temperature rise is larger than a failure voltage determination value. Alternatively, the inspection system adopts a predetermined inspecting step and a rapid inspecting step respectively to determine whether a light-emitting device fails.

Abstract: Disclosed is a method for testing a light-emitting device comprising the steps of: providing a light-emitting device comprising a plurality of light-emitting diodes; driving the plurality of the light-emitting diodes with a current; generating an image of the light-emitting device; and determining a luminous intensity of each of the light-emitting diodes; wherein the magnitude of the current is determined such that the current density driving each of the light-emitting diodes is smaller than or equal to 300 mA/mm2.

Abstract: The present invention discloses a lighting jig for testing a backlight module, comprising a switch unit and a delay unit; wherein the switch unit is connected to a power supply, and when the switch unit is in closed position, a power output terminal of the lighting jig is electrically connected to a power input terminal of the backlight module, a closing signal is generated at the same time, and the closing signal is output to the delay unit; and the delay unit is connected to the power supply, and outputs a delayed power signal to the power input terminal of the backlight module upon receipt of the closing signal output from the switch unit so as to delay the lighting up of the backlight module.

Abstract: An organic light emitting display device according to example embodiments includes a display unit, a test data line to which a test data voltage is applied during a sheet unit test, a test gate line to which a first voltage is applied during the sheet unit test and to which a second voltage is applied during a normal operation of the organic light emitting display device, a plurality of test transistors configured to selectively couple the test data line to a plurality of data lines in the display unit in accordance with a voltage provided by the test gate line, and at least one redundant element configured to maintain the test gate line at the second voltage during the normal operation even if the test gate line is damaged.

Abstract: Various embodiments provide a method for ascertaining a type of a gas discharge lamp using an electronic ballast for operating different types of gas discharge lamps, wherein the different types of gas discharge lamps differ in at least one operating parameter, wherein the method may include: a) preheating at least one filament in the gas discharge lamp for a predetermined preheating time; b) measuring a physical variable which is characteristic for the type of the gas discharge lamp at the end of the preheating time and providing the measurement value of said variable; and c) ascertaining the lamp type on the basis of the measurement value which is provided, wherein the preheating time is increased by a predetermined time period and the b) and c) are repeated if the lamp type in c) cannot be ascertained uniquely. Moreover, various embodiments provide an electronic ballast for operating at least two different types of gas discharge lamps which have at least one different operating parameter.

Abstract: A detection apparatus for light-emitting diode chip comprising a substrate with the function of photoelectric conversion and a probing device is disclosed. The substrate is designed to bear at least one light-emitting diode chip. The probing device comprises a power supply and at least two conductive elements. The two ends of the conductive elements are respectively electrically connected to the light-emitting diode chip and the power supply to enable the light-emitting diode chip to emit light beams. Some of the light beams are emitted from the light-emitting diode chip toward the substrate such that the light beams emitted by the light-emitting diode chip are converted into an electric signal by the substrate.

Abstract: A detection apparatus for light-emitting diode chip comprising a light-collecting apparatus having an opening, a bracing component and a probing device is disclosed. The bracing component is designed to bear at least one light-emitting diode chip. The probing device comprises a power supply and at least two flexible current-transporting elements. The two ends of the current-transporting elements are respectively electrically connected to the light-emitting diode chip and the power supply to enable the light-emitting diode chip to emit light beams. Besides, the detection apparatus for light-emitting diode chip of the present invention further comprises a thimble to push the light-emitting diode chip into the inside of the light-collecting apparatus via the opening such that the light beams emitted by the light-emitting diode chip are collected by the light-collecting apparatus.

Abstract: A defect detection method for an organic EL element having a first electrode, a second electrode, and a functional layer and a light-emission layer disposed between the electrodes, including: applying a first voltage, between the electrodes, that, when the organic EL element includes, between the electrodes, a defective portion that is a potential cause of non-light emission of the light-emission layer, reduces electrical resistance of a first portion, of the functional layer, corresponding to the defective portion and makes the organic EL element detectable as a dark spot, whose light-emission layer does not emit light; and after applying the first voltage, applying a second voltage between the electrodes and detecting whether or not the organic EL element is the dark spot, the second voltage, when the organic EL element does not include the defective portion, causing the light-emission layer to emit light.

Abstract: A light emitting element circuit includes a light emitting element (1), a current supply path to the light emitting element (1), a constant current circuit (2) that supplies a current to the light emitting element (1) via the current supply path, and an electric discharge path that discharges an electric charge accumulated at the light emitting element (1) and at a region connected between the both electrodes when the constant current circuit (2) stops a current supply to the light emitting element (1). A light emitting element failure detector (4) that detects a short-circuit of the light emitting element (1) in a light emitting element circuit includes a current instantaneous interruption circuit (5), a voltage detector (60), and a determiner (62).

Abstract: A light emitting element failure detector (4) includes a light emitting element (1), a constant current circuit (2) which supplies an electric current to the light emitting element (1), and an electric discharge path which discharges an electric charge such as the light emitting element (1). A light emitting element failure detector (4) further includes an instantaneous current interruption circuit (5) which instantaneously interrupts an electric current to the light emitting element (1) by a current supply path different from the electric discharge path, a diode (60), a DC power supply (61), and a current detector (62). The DC power supply (61) generates a direct-current reference voltage having a positive value lower than a voltage between the anode and cathode of the light emitting element (1) in a normal state. The DC power supply (61), the diode (60), and the current detector (62) which are connected in series constitute a parallel electric path of the light emitting element (1).

Abstract: A LED light source measuring instrument includes a shell portion and a test portion. The shell portion supports the test portion. The test portion includes an electrode seat, the electrode seat includes a first surface and a second surface opposite to the first surface. The first surface of the electrode seat provides two electrodes which electrically connect to the electrode plates of the LED light source for supplying power to the LED light source. The second surface of the electrode seat has a cooling device attached thereto for taking heat generated by the LED light source. A hole passing through the first surface and the second surface of the electrode seat is subjected to a vacuum, for automatically securing the electrode plates of the LED light source to the electrodes on the first surface of the electrode seat.

Abstract: In various embodiments, a method for calibrating a lighting device is provided. The lighting device may include at least one semiconductor light source. The method may include: determining a thermal power loss of the at least one semiconductor light source; determining an electrical power of the at least one semiconductor light source; and determining a light power of the at least one semiconductor light source from the electrical power and the thermal power loss.

Abstract: A system is provided. The system includes a light emitting diode and a monitoring module. The monitoring module is communicably coupled to the light emitting diode. The monitoring module is configured to receive one or more signals indicative of power consumption of the light emitting diode. Further, the monitoring module is configured to determine a condition of the light emitting diode based, at least in part, on the received signals.

Abstract: Disclosed herein is a method of detecting an LED failure in a series-connected string of LEDs using a parameter indicative of a voltage difference between a voltage across the string at a predetermined relatively high current and a voltage across the string at a predetermined relatively low current. The disclosure extends to controllers configured to detect an LED failure in a string of LEDs, to LED lighting units comprising such controllers, and to lighting subsystems, for instance automobile lighting subsystems.

Abstract: A method for detecting a leakage bright spot includes: providing a driving circuit of data lines and a gate drive of a gate side and connecting a terminal area of the gate side by conductive adhesive; dividing the terminal area of the gate side into a first area and a second area, turning on switches of pixel electrodes, and transmitting a driving signal to the data side; and detecting the leakage bright spot by optionally driving conductive terminals on the first area or the second area of the gate side. The present disclosure further provides a device for detecting a leakage bright spot.

Abstract: A system reads a desired circuit parameter from a pixel circuit that includes a light emitting device, a drive device to provide a programmable drive current to the light emitting device, a programming input, and a storage device to store a programming signal. One embodiment of the extraction system turns off the drive device and supplies a predetermined voltage from an external source to the light emitting device, discharges the light emitting device until the light emitting device turns off, and then reads the voltage on the light emitting device while that device is turned off. The voltages on the light emitting devices in a plurality of pixel circuits may be read via the same external line, at different times.