Display device

Abstract

The display device may include a plurality of light-emitting elements provided in a plurality of subpixels and connected to a first power line, a reference current generation circuit connected to a third power line, and a plurality of light-emitting circuits provided in a plurality of subpixels and connected to the reference current generation circuit and the plurality of light-emitting elements. The reference current generation circuit and the plurality of light-emitting circuits may be commonly connected to a second power line, and the reference current generation circuit and the plurality of light-emitting circuits may be commonly connected to a measurement line.

Description

[Technical Field]

[0001] The examples relate to display devices. [Background technology]

[0002] The display market is growing year by year, and its range of applications is continuously expanding. Along with this expansion of applications, the resolution and characteristics of products are becoming more diverse.

[0003] As product specifications become more diverse, the methods for driving displays are also becoming more complex.

[0004] In the case of driver ICs used to drive display devices, they are designed to fit that specific purpose. Therefore, the range of applications for the design is limited, and a driver IC tailored to each product is required if necessary.

[0005] Conventional display devices employ various methods to ensure brightness uniformity. For example, internal compensation is performed by configuring light-emitting circuits in pixels (or subpixels), or external compensation is performed using specific methods.

[0006] On the other hand, the majority of the circuit configuration for the operation of the light-emitting circuit includes its own capacitors, ensuring constant current characteristics.

[0007] Figure 1 is a circuit diagram illustrating an existing light-emitting circuit.

[0008] As shown in Figure 1, the existing light-emitting circuit includes a drive transistor M1, a scan transistor M2, a sensing transistor M3, and a capacitor CSTG.

[0009] When the scan transistor M2 is turned on in response to the scan signal SCAN, the data signal VDATA is supplied to the drive transistor M1 via the scan transistor M2. The drive transistor M1 supplies a light-emitting current corresponding to the data signal VDATA to the light-emitting element ED, causing the light-emitting element ED to emit light.

[0010] The capacitor CSTG allows the light-emitting current to be supplied as a constant current to the light-emitting element ED.

[0011] When the sensing transistor M3 is turned on in response to the sensing control signal SEN, the light-emitting current flowing through the drive transistor M1 is detected as the sensing signal VSEN. The characteristics of the light-emitting circuit are calibrated or compensated using the sensing signal VSEN.

[0012] Meanwhile, the light-emitting circuit of an active matrix display device adjusts brightness by either applying the PWM (pulse width modulation) method itself, or using a PWM method that utilizes the PAM (pulse amplitude modulation) method. In such cases, a capacitor is necessarily provided inside each pixel (or sub-pixel).

[0013] When a light-emitting circuit is designed such that a capacitor is provided inside each pixel, constraints such as area restrictions may occur, or additional problems may arise due to the capacitor inside each pixel.

[0014] Meanwhile, for a light-emitting element such as an LED, brightness is determined by the value of the light-emitting current. Due to manufacturing characteristic differences or environmental differences, differences in the value of the light-emitting current may occur, or the efficiency of the light-emitting element may vary greatly. In such cases, it is troublesome that the brightness of the display must be adjusted to be constant outside the light-emitting circuit, for example by a controller or a display driving device, to align the brightness uniformity of the entire display screen. In addition, it becomes necessary to adjust the value of the light-emitting current to align the brightness between display screens, and no solution for resolving this issue has been proposed yet. Summary of the Invention Problem to be Solved by the Invention

[0015] An object of an embodiment is to provide a display device having a novel structure.

[0016] Another object of an embodiment is to provide a display device that provides a novel driving method.

[0017] Still another object of an embodiment is to provide a display device in which a capacitor is not provided in a light-emitting circuit.

[0018] Yet another object of an embodiment is to provide a display device that does not require a display driving circuit including a converter that converts digital data into analog data.

[0019] A further object of an embodiment is to provide a display device capable of efficiently measuring a reference current and / or a light-emitting current.

[0020] A still further object of an embodiment is to provide a display device with a simple circuit structure by using one measurement line.

[0021] Yet another object of an embodiment is to provide a display device capable of ensuring uniformity of light-emitting current between displays (or frames) and between blocks, that is, luminance uniformity.

[0022] The technical problems of the embodiments are not limited to those described in this section, and include those that can be understood from the description of the invention. Means for Solving the Problem

[0023] To achieve the aforementioned or other objective, according to one aspect of the embodiment, a display device including a plurality of subpixels includes a plurality of light-emitting elements provided in the plurality of subpixels and connected to a first power line, a reference current generating circuit connected to a third power line, and a plurality of light-emitting circuits provided in the plurality of subpixels and connected to the reference current generating circuit and the plurality of light-emitting elements, wherein the reference current generating circuit and the plurality of light-emitting circuits are commonly connected to a second power line, and the reference current generating circuit and the plurality of light-emitting circuits are commonly connected to a measurement line.

[0024] The reference current generation circuit may include a first transistor, a first control switch between the first transistor and the second power supply line, and a second control switch between the first transistor and the measurement line.

[0025] Each of the plurality of light-emitting circuits may include the first transistor of the reference current generation circuit, a first transistor constituting a mirror circuit, a first control switch between the first transistor and the second power supply line, and a second control switch between the first transistor and the measurement line.

[0026] The reference current generation circuit may include a third control switch connected to the first transistor for turning the reference current on and off.

[0027] Each of the plurality of light-emitting circuits may include a third control switch between the light-emitting element and the first transistor, a fourth control switch between the third power supply line and the first transistor, and a fifth control switch connected to the first transistor for turning the light-emitting current on and off.

[0028] In the light emission mode, the first and third control switches of the reference current generation circuit can be turned on, the second control switch can be turned off, the plurality of first control switches, the plurality of third control switches, and the plurality of fifth control switches of the plurality of light emission circuits can be turned on, and the plurality of second control switches and the plurality of fourth control switches can be turned off.

[0029] In the reference current measurement mode, the first control switch of the reference current generation circuit can be turned off, the second and third control switches can be turned on, and the fifth control switch of each of the plurality of light-emitting circuits can be turned off.

[0030] In the light emission current measurement mode, the first control switch of the reference current generation circuit may be turned off, the second and third control switches of the reference current generation circuit may be turned on, the first and fourth control switches of the light emission circuit to be measured among the plurality of light emission circuits may be turned off, the second, third and fifth control switches of the reference current generation circuit may be turned on, and the fifth control switch of the remaining light emission circuit among the plurality of light emission circuits may be turned off.

[0031] In the non-luminescent current measurement mode, the first control switch of the reference current generation circuit may be turned off, the second and third control switches of the reference current generation circuit may be turned on, the first and third control switches of the luminescent circuit to be measured among the plurality of luminescent circuits may be turned off, the second, fourth and fifth control switches of the luminescent circuit to be measured may be turned on, and the fifth control switch of the remaining luminescent circuit among the plurality of luminescent circuits may be turned off.

[0032] In the reference current measurement mode during light emission, the first control switch of the reference current generation circuit can be turned off, the second and third control switches can be turned on, and the first, third and fifth control switches of at least one of the plurality of light emission circuits can be turned on, while the second and fourth control switches can be turned off.

[0033] In the reference current measurement mode when no light is emitted, the first control switch of the reference current generation circuit can be turned off, the second and third control switches can be turned on, and the first, fourth and fifth control switches of at least one of the plurality of light-emitting circuits can be turned on, while the second and third control switches can be turned off.

[0034] In the light emission current measurement mode during light emission, the first and third control switches of the reference current generation circuit are turned on, the second control switch is turned off, the first and fourth control switches of at least one of the plurality of light emission circuits are turned off, and the second, third, and fifth control switches can be turned on.

[0035] In the non-light-emitting current measurement mode when no light is emitted, the first and third control switches of the reference current generation circuit are turned on, the second control switch is turned off, the first and third control switches of at least one of the plurality of light-emitting circuits are turned off, and the second, fourth, and fifth control switches can be turned on.

[0036] The display device may further include a current measuring circuit connected to the measurement line that measures at least one of a reference current or an illumination current, and a current control circuit that controls at least one of a voltage generating circuit or the reference current generating circuit based on the measured current. [Effects of the Invention]

[0037] The effects of the display device according to the embodiment are as follows:

[0038] According to at least one of the embodiments, since the light-emitting circuit does not have a capacitor, it is not subject to area constraints, which has the advantage of increasing the aperture ratio and improving brightness.

[0039] According to at least one of the embodiments, a display driver that includes a converter for converting digital data to analog data is not required, which has the advantage of simplifying the circuit structure, reducing the occupied area, and saving costs.

[0040] According to at least one of the embodiments, the light-emitting current for causing the light-emitting element to emit light is adjusted to be different, which has the advantage that precise brightness adjustment is possible at any time.

[0041] According to at least one of the embodiments, the advantage is that precise brightness adjustment is possible at any time by adjusting the reference current to be different.

[0042] According to at least one of the embodiments, the reference voltage for adjusting the reference current is adjusted to be different, which has the advantage that precise brightness adjustment is possible at any time.

[0043] According to at least one of the embodiments, by adjusting the reference voltage and reference current simultaneously, the number of different light-emitting currents increases, allowing for more precise brightness adjustment and enabling the realization of high-definition images.

[0044] According to at least one of the embodiments, brightness uniformity between displays (or frames) can be ensured by adjusting a reference voltage and / or reference current between displays (or frames).

[0045] According to at least one of the embodiments, in a plurality of blocks (or modules) each including a voltage generation circuit, a reference current generation circuit, and a plurality of light-emitting circuits, the reference voltage provided by the voltage generation circuit of each module and / or the reference current generated by the reference current generation circuit can be adjusted. This ensures brightness uniformity of the light-emitting current generated by the light-emitting circuits between modules.

[0046] According to at least one of the embodiments, various currents, namely the reference current, light-emitting current, and non-light-emitting current, can be measured via a measurement line commonly connected to the reference current generation circuit and the light-emitting circuit. By controlling (or compensating) the reference voltage and reference current to adjust based on these measured various currents, a more precise brightness uniformity can be ensured.

[0047] The additional scope of applicability of the examples will become apparent from the detailed description below. However, since various changes and modifications within the concept and scope of the examples will be clearly understood by those skilled in the art, the detailed description and specific examples, such as preferred examples, should be understood as merely illustrative. [Brief explanation of the drawing]

[0048] [Figure 1] Figure 1 is a circuit diagram illustrating an existing light-emitting circuit. [Figure 2] Figure 2 is a block diagram illustrating a display device according to the first embodiment. [Figure 3] Figure 3 is a block diagram illustrating a display device according to the second embodiment. [Figure 4]Figure 4 illustrates a display device according to a second embodiment operating in light emission mode. [Figure 5] Figure 5 illustrates a display device according to a second embodiment operating in reference current measurement mode. [Figure 6] Figure 6 illustrates a display device according to a second embodiment operating in light emission current measurement mode. [Figure 7] Figure 7 illustrates a display device according to a second embodiment operating in non-luminescence current measurement mode. [Figure 8] Figure 8 is a block diagram illustrating a display device according to the third embodiment. [Figure 9] Figure 9 illustrates a display device according to a third embodiment, which operates in a reference current measurement mode during light emission. [Figure 10] Figure 10 illustrates a display device according to a third embodiment, which operates in a reference current measurement mode when no light is emitted. [Figure 11] Figure 11 illustrates a display device according to a third embodiment, which operates in a light emission current measurement mode during light emission. [Figure 12] Figure 12 illustrates a display device according to a third embodiment that operates in a non-luminescent current measurement mode when no light is emitted.

[0049] The size, shape, and numerical values ​​of the components shown in the drawings do not necessarily match those of the actual components. Furthermore, even if the same component is shown with different sizes, shapes, and numerical values ​​in different drawings, this is merely one example on the drawing, and the same component can have the same size, shape, and numerical values ​​in different drawings.

[0050] The embodiments disclosed herein will be described in detail below with reference to the attached drawings, but identical or similar components will be given the same reference numeral regardless of the drawing reference numerals, and redundant descriptions will be omitted. The suffixes “module” and “part” used for components in the following description are given or used interchangeably to facilitate the writing of the specification and do not have any mutually distinguishing meaning or role in themselves. The attached drawings are provided to facilitate the understanding of the embodiments disclosed herein and do not limit the technical ideas disclosed herein. Furthermore, when it is said that an element such as a layer, region, or substrate is “on” another component, this includes elements that are directly on other elements or where other intermediate elements may exist between them.

[0051] In the following, "~module," "~part," etc., can be composed of "~circuit" or "integrated circuit." "~module," "~part," etc., can be used interchangeably with "~circuit" or "integrated circuit."

[0052] [First Embodiment]

[0053] Figure 2 is a block diagram illustrating a display device according to the first embodiment.

[0054] Referring to Figure 2, the display device according to the first embodiment may include a reference current generation circuit 110, a plurality of light-emitting circuits 130-1 to 130-N, a plurality of light-emitting elements 120-1 to 120-N, and so on.

[0055] The display device according to the first embodiment may include a display panel. The display panel may include multiple pixels. The display panel may include multiple subpixels SP-1 to SP-N. A single pixel may contain multiple subpixels SP-1 to SP-N. [Modes for carrying out the invention]

[0056] A display panel may include a display area containing multiple pixels and a non-display area excluding the display area. In a display panel, the light-emitting area may be the area corresponding to each of the multiple subpixels SP-1 to SP-N, and the non-light-emitting area may be the area between the multiple subpixels SP-1 to SP-N.

[0057] The voltage generation circuit 150, the reference current generation circuit 110, the multiple light-emitting circuits 130-1 to 130-N, and the multiple light-emitting elements 120-1 to 120-N may be provided on the display panel. The multiple light-emitting elements 120-1 to 120-N may be provided in the light-emitting region.

[0058] For example, the voltage generation circuit 150, the reference current generation circuit 110, and the multiple light-emitting circuits 130-1 to 130-N may each be individually implemented as integrated circuits (ICs).

[0059] As another example, the voltage generation circuit 150 and the reference current generation circuit 110 may be embodied as a single integrated IC. In such a case, the integrated IC may be provided in the light-emitting region or the non-light-emitting region. Multiple light-emitting circuits 130-1 to 130-N may each be provided in multiple subpixels SP-1 to SP-N together with multiple light-emitting elements 120-1 to 120-N. For example, the first light-emitting circuit 130-1 and the first light-emitting element 120-1 may be provided in the first subpixel SP-1.

[0060] As yet another example, the voltage generation circuit 150, the reference current generation circuit 110, and the multiple light-emitting circuits 130-1 to 130-N may be embodied as a single integrated IC. In such a case, the integrated IC is provided in the non-light-emitting region, and the multiple light-emitting elements 120-1 to 120-N may be provided in the multiple subpixels SP-1 to SP-N.

[0061] The drawing shows multiple subpixels SP-1 to SP-N arranged in a single row along the horizontal direction, but the multiple subpixels SP-1 to SP-N may also be arranged in a single row along the vertical direction or in a matrix configuration.

[0062] Multiple subpixels SP-1 to SP-N are electrically connected to a first power line 141, a second power line 142, and a measurement line 145. The first power supply voltage EVDD is supplied to the first power line 141, and the second power supply voltage EVSS may be supplied to the second power line 142. The first power supply voltage EVDD is a high potential voltage and may be greater than the second power supply voltage EVSS, which is a low potential voltage. The second power supply voltage EVSS may be, for example, grounded or 0V, but is not limited to these. The light emission current of at least one of the multiple light emission circuits 130-1 to 130-N of the multiple subpixels SP-1 to SP-N is measured via the measurement line 145.

[0063] Multiple subpixels SP-1 to SP-N may include multiple red subpixels, multiple green subpixels, and multiple blue subpixels. A unit pixel is formed by adjacent red, green, and blue subpixels. In the drawing, the first subpixel SP-1 may be a red subpixel, the second subpixel SP-2 may be a green subpixel, and the third subpixel SP-3 may be a blue subpixel, but this is not limited to them.

[0064] The first subpixel SP-1 can emit red light, the second subpixel SP-2 can emit green light, and the third subpixel SP-3 can emit blue light. Furthermore, the subpixels SP-1 to SP-N may further include multiple transparent subpixels that emit transparent light.

[0065] Each of the multiple subpixels SP-1 to SP-N may contain at least one or more light-emitting elements 120-1 to 120-N. For example, the first subpixel may contain at least one or more red light-emitting elements for emitting red light. For example, the second subpixel may contain at least one or more green light-emitting elements for emitting green light. For example, the third subpixel may contain at least one or more blue light-emitting elements for emitting blue light. The multiple light-emitting elements 120-1 to 120-N may include organic semiconductor light-emitting elements, inorganic semiconductor light-emitting elements, micro-LEDs (μ-LEDs), nano-LEDs, and the like.

[0066] Multiple light-emitting elements 120-1 to 120-N may be connected in common to the first power supply line 141. Each of the multiple light-emitting elements 120-1 to 120-N may be connected to a plurality of light-emitting circuits 130-1 to 130-N.

[0067] Multiple light-emitting circuits 130-1 to 130-N can drive multiple light-emitting elements 120-1 to 120-N of multiple subpixels SP-1 to SP-N to emit multiple colored lights.

[0068] Multiple light-emitting circuits 130-1 to 130-N may be connected in common to the second power supply line 142. Multiple light-emitting circuits 130-1 to 130-N may be connected in common to the third power supply line 143. Multiple light-emitting circuits 130-1 to 130-N may be connected in common to the measurement line 145.

[0069] Multiple light-emitting circuits 130-1 to 130N can generate light-emitting currents IEM1 to IEMN to supply to the corresponding light-emitting elements 120-1 to 120-N between the first power line 141 and the second power line 142. These light-emitting currents IEM1 to IEMN can also be referred to as drive currents, brightness currents, etc.

[0070] For example, in the first subpixel SP-1, the first light-emitting circuit 130-1 is electrically connected to the first light-emitting element 120-1 and can be driven to emit a first light-emitting current IEM1 from the first light-emitting element 120-1 so that at least the first color light is emitted from the first light-emitting element 120-1. For example, in the second subpixel SP-2, the second light-emitting circuit 130-2 is electrically connected to at least one or more second light-emitting elements 120-2 and can be driven to emit a second color light from the second light-emitting element 120-2 so that a second light-emitting current IEM2 is supplied from the second light-emitting element 120-2. In the third subpixel SP-3, the third light-emitting circuit 130-3 is electrically connected to the third light-emitting element 120-3 and can be driven to emit a third color light from the second light-emitting element 120-3 so that a third light-emitting current IEM3 is supplied from the third light-emitting element 120-3. For example, the first color light may be red light, the second color light may be green light, and the third color light may be blue light, but this is not a limitation.

[0071] On the other hand, multiple light-emitting circuits 130-1 to 130N can output light-emitting currents IEM1 to IEMN individually or simultaneously via the measurement line 145. The output currents IEM1 to IEMN can be measured by the current measurement circuit 170, which will be described later.

[0072] On the other hand, the reference current generation circuit 110 can generate a reference current IREF. The reference current generation circuit 110 may be connected in common to multiple subpixels SP-1 to SP-N.

[0073] The reference current IREF can be used to generate multiple light-emitting currents IEM1 to IEMN that flow through multiple subpixels SP-1 to SP-N. That is, the reference current IREF generated in the reference current generation circuit 110 is copied to the multiple subpixels SP-1 to SP-N, and light-emitting currents IEM1 to IEMN are generated in each subpixel SP-1 to SP-N. For example, a current mirroring scheme can be used in each subpixel SP-1 to SP-N to generate light-emitting currents IEM1 to IEMN corresponding to the reference current IREF. For this purpose, a current mirroring circuit may be configured by at least one transistor in the reference current generation circuit 110 and at least one transistor in each of the multiple light-emitting circuits 130-1 to 130-N. At least one transistor in the reference current generation circuit 110 is connected to a diode. The gate of at least one transistor in the reference current generation circuit 110 and the gate of at least one transistor in each of the multiple light-emitting circuits 130-1 to 130-N may be connected in common to a G node.

[0074] The reference current IREF and the light-emitting currents IEM1 to IEMN may be constant currents. A constant current means that a constant current flows even if the voltage across its terminals changes.

[0075] The light-emitting currents IEM1 to IEMN may correspond to the reference current IREF. The light-emitting currents IEM1 to IEMN may be the same as or greater than the reference current IREF. That is, multiple light-emitting circuits 130-1 to 130-N can generate light-emitting currents IEM1 to IEMN that are the same as or greater than the reference current IREF according to a predetermined ratio, i.e., the copy ratio.

[0076] The copy ratio may be determined by designing the aspect ratios of each transistor in the multiple light-emitting circuits 130-1 to 130-N to be different from the aspect ratio of the transistor in the reference current generation circuit 110.

[0077] For example, if the aspect ratio of the transistors in the light-emitting circuits 130-1 to 130-N is the same as the aspect ratio of the transistor in the reference current generation circuit 110, the copy ratio can be set to 1, and the light-emitting currents IEM1 to IEMN generated by the multiple light-emitting circuits 130-1 to 130-N can be the same as the reference current IREF. For example, if the aspect ratio of the transistors in the light-emitting circuits 130-1 to 130-N is greater than the aspect ratio of the transistor in the reference current generation circuit 110, the copy ratio will be greater than 1, and therefore the light-emitting currents IEM1 to IEMN generated by the light-emitting circuits 130-1 to 130-N will be greater than the reference current IREF.

[0078] Therefore, by freely designing the aspect ratio of each transistor in the multiple light-emitting circuits 130-1 to 130-N, the light-emitting currents IEM1 to IEMN required for the subpixel SP-1 to SP-N can be obtained accurately and easily.

[0079] According to the embodiment, by utilizing the copy ratio, the aspect ratio of the transistors in the reference current generation circuit 110 is designed to be smaller than the aspect ratio of the transistors in the light-emitting circuits 130-1 to 130-N, thereby enabling the reference current generation circuit 110 to generate a relatively small reference current IREF. This reduces the burden on generating a large reference current IREF, reduces the size of the reference current generation circuit 110, and saves power consumption. Furthermore, since the multiple light-emitting currents IEM1 to IEMN of the multiple light-emitting circuits 130-1 to 130-N have large values, the contrast ratio is improved, and high brightness can be achieved.

[0080] Meanwhile, the reference current generation circuit 110 is electrically connected to the third power supply line 143, the second power supply line 142, and the measurement line 145.

[0081] The third power line 143 may be connected in common to the reference current generation circuit 110 and the multiple light-emitting circuits 130-1 to 130-N. The second power line 142 may be connected in common to the reference current generation circuit 110 and the multiple light-emitting circuits 130-1 to 130-N.

[0082] The measurement line 145 may be connected in common to the reference current generation circuit 110 and the multiple light-emitting circuits 130-1 to 130-N.

[0083] Therefore, the reference current IREF generated by the reference current generation circuit 110 is measured via the measurement line 145, or the multiple light-emitting currents IEM1 to IEMN generated by the multiple light-emitting circuits 130-1 to 130-N are measured individually or simultaneously via the measurement line 145. If the light-emitting circuits 130-1 to 130-N are selected to be connected between the first power supply line 141 and the second power supply line 142, the light-emitting currents IEM1 to IEMN are generated in the light-emitting circuits 130-1 to 130-N.

[0084] Furthermore, non-luminescent currents generated by multiple light-emitting circuits 130-1 to 130-N are measured via the measurement line 145. When light-emitting circuits 130-1 to 130-N are selected to be connected between the third power supply line 143 and the second power supply line 142, non-luminescent currents are generated in the light-emitting circuits 130-1 to 130-N.

[0085] The third power supply voltage PVDD is supplied to the third power supply line 143. The third power supply voltage PVDD can be similar to the first power supply voltage EVDD as a high potential voltage. For example, the third power supply voltage PVDD may be smaller than the first power supply voltage EVDD, but is not limited to this.

[0086] Since the second power supply line 142 is commonly connected to the reference current generation circuit 110 and the multiple light-emitting circuits 130-1 to 130-N, the transistors of the reference current generation circuit 110 and the multiple transistors of the multiple light-emitting circuits 130-1 to 130-N that constitute the current mirror circuit can commonly use the second power supply voltage EVSS supplied to the second power supply line 142. Therefore, because the transistors of the reference current generation circuit 110 and the multiple transistors of the multiple light-emitting circuits 130-1 to 130-N are simultaneously affected by the IR drop associated with the second power supply voltage EVSS, they are not affected by the changes in the respective light-emitting currents IEM1 to IEMN of the multiple subpixels SP-1 to SP-N, thus preventing image quality defects.

[0087] On the other hand, each of the multiple light-emitting circuits 130-1 to 130-N uses digital data and program signals to adjust the ON interval (or light-emitting interval) of the light-emitting elements 120-1 to 120-N on a periodic (or frame) basis, enabling gradation expression for the image. Depending on the digital signal, it may be determined whether or not to supply the light-emitting currents IEM1 to IEMN generated by the light-emitting circuits 130-1 to 130-N to the light-emitting elements 120-1 to 120-N. For example, the digital data may include signals regarding the light emission / non-light emission of the light-emitting elements 120-1 to 120-N. For example, if the digital data is "1", the light-emitting currents IEM1 to IEMN generated by the light-emitting circuits 130-1 to 130-N are supplied to the light-emitting elements 120-1 to 120-N, allowing the light-emitting elements 120-1 to 120-N to emit light. For example, if the digital data is "0", the light-emitting current IEM1 to IEMN generated by the light-emitting circuits 130-1 to 130-N is not supplied to the light-emitting elements 120-1 to 120-N, and therefore the light-emitting elements 120-1 to 120-N do not emit light.

[0088] The program signal may include grayscale information as a control signal for writing input data. By determining that the width of the ON interval (or light emission interval) differs according to the grayscale information included in the program signal, images with different grayscales and brightness levels are displayed. For example, the larger the ON interval, the higher the grayscale level displayed. For example, by having the light-emitting elements 120-1 to 120-N emit light for the same subpixel in different ON intervals per frame, images with different grayscale levels per frame are displayed.

[0089] Therefore, whether or not the light-emitting elements 120-1 to 120-N emit light is determined according to the digital data, and the ON interval (light-emitting interval) of the light-emitting elements 120-1 to 120-N is adjusted according to the program signal, thereby displaying an image with the desired gradation and brightness.

[0090] In the drawing, the G node may be one node between the gate of the transistor of the reference current generation circuit 110 that constitutes the current mirror circuit and the gates of each of the transistors of the multiple light-emitting circuits 130-1 to 130-N.

[0091] A reference current IREF generated by the reference current generation circuit 110 generates a predetermined voltage at the G node via the transistor of the reference current generation circuit 110. This predetermined voltage generates multiple light-emitting currents IEM1 to IEMN in the transistors of the multiple light-emitting elements 120-1 to 120-N. In this case, as described above, by designing the aspect ratios of the transistors of the light-emitting elements 120-1 to 120-N to be the same as or different from the aspect ratios of the transistors of the reference current generation circuit 110, the same or different light-emitting currents IEM1 to IEMN are generated in each of the transistors of the multiple light-emitting elements 120-1 to 120-N based on the voltage on the G node.

[0092] On the other hand, in the embodiment, multiple subpixels SP-1 to SP-N may be driven simultaneously. That is, multiple subpixels SP-1 to SP-N are driven simultaneously within one frame, and the ON intervals of each light-emitting element 120-1 to 120-N of the multiple subpixels SP-1 to SP-N are adjusted so that images with different gradations are displayed on each subpixel SP-1 to SP-N.

[0093] On the other hand, as mentioned above, the reference current generation circuit 110 and the multiple light-emitting circuits 130-1 to 130-N may be commonly connected to the second power supply line 142 and also commonly connected to the measurement line 145.

[0094] As a first example, a reference current generation circuit 110 connected to the third power line 143 and the second power line 142 can generate a reference current IREF.

[0095] As a second example, multiple light-emitting circuits 130-1 to 130-N connected to the first power line 141 and the second power line 142 can generate multiple light-emitting currents IEM1 to IEMN.

[0096] As a third example, the reference current IREF generated by the reference current generation circuit 110 is output via the measurement line 145.

[0097] As a fourth example, multiple light-emitting currents IEM1 to IEMN generated by multiple light-emitting circuits 130-1 to 130-N may be output individually or simultaneously via the measurement line 145.

[0098] As a fifth example, the non-luminescent currents generated by the multiple light-emitting circuits 130-1 to 130-N are output via the measurement line 145.

[0099] On the other hand, in the embodiment, the reference current IREF, light-emitting currents IEM1~IEMN and / or non-light-emitting current output via the measurement line 145 are measured and can be used to control the reference current generation circuit 110 and / or a plurality of light-emitting circuits 130-1~130-N.

[0100] For this purpose, the display device according to the first embodiment may include a current measurement circuit 170, a current control circuit 180, and the like.

[0101] The current measurement circuit 170 is electrically connected to the reference current generation circuit 110 and a plurality of light-emitting circuits 130-1 to 130-N via the measurement circuit 145. The current measurement circuit 170 measures the reference current IREF, light-emitting currents IEM1 to IEMN and / or non-light-emitting current via the measurement circuit 145, and calculates the measurement result (Equations 3 to 6). M1 ~I M4 You can obtain ).

[0102] The current control circuit 180 can generate control signals (such as E11 and C21 in Figure 3) to control the reference current generation circuit 110 and / or multiple light-emitting circuits 130-1 to 130-N based on the reference current IREF, light-emitting currents IEM1 to IEMN, and / or non-light-emitting currents measured by the current measurement circuit 170. As will be described later, in response to one of these control signals (such as E11 and C21), a plurality of selection switches 156-1 of the voltage generation circuit 150 (150 in Figure 3) are selectively turned on to adjust the reference voltage VREF. Also, in response to another control signal (such as C21), a plurality of selection switches 112-1 of the reference current generation circuit 110 are selectively turned on to adjust the reference current IREF.

[0103] For example, if the voltage generation circuit 150, the current generation circuit 110, and the multiple light-emitting circuits 130-1 to 130-N are configured with a single drive IC (first IC), the current measurement circuit 170 and the current control circuit 180 may be configured with separate ICs (second ICs) from the first IC. Alternatively, the first IC and the second IC may be implemented as a single unit.

[0104] The current measurement circuit 170 can measure a reference current IREF, light-emitting currents IEM1 to IEMN, and / or non-light-emitting currents. For example, the current measurement circuit 170 can measure the reference current IREF, light-emitting currents IEM1 to IEMN, and / or non-light-emitting currents via the measurement circuit 150 during the production process of each first IC or during the display operation of the display device according to the first embodiment.

[0105] The current control circuit 180 can obtain, based on the measured reference current IREF, light-emitting currents IEM1 to IEMN and / or non-light-emitting current, the difference in reference current IREF or light-emitting current caused by characteristic differences between multiple first ICs that may occur during the production of multiple first ICs, as well as the difference in reference current IREF or light-emitting current that may occur in the driving environment or under specific conditions.

[0106] Furthermore, the current control circuit 180 can adjust the reference voltage VREF by controlling the voltage generation circuit 150 or adjust the reference current IREF by controlling the reference current generation circuit 110 based on control signals (E11, C21, etc.) that include compensation information based on the difference. This ensures uniformity of the currents between multiple first ICs, such as the reference current IREF and the light emission current, thereby improving image quality.

[0107] [Second Example]

[0108] Figure 3 is a block diagram illustrating a display device according to the second embodiment. Figure 3 illustrates the circuit configurations of the voltage generation circuit 150, the reference current generation circuit 110, and the first light-emitting circuit 130-1 of the first subpixel SP-1, as shown in Figure 2. The current measurement circuit 170 and the current control circuit 180 shown in Figure 2 may also be included in Figure 3. Figure 3 illustrates only the circuit configuration of the first light-emitting circuit 130-1 of the first subpixel SP-1 as shown in Figure 2. The circuit configurations of the second light-emitting circuits 130-2 to the Nth light-emitting circuits 130-N may be the same as the circuit configuration of the first light-emitting circuit 130-1. Therefore, the explanation for the circuit configurations of the second light-emitting circuits 130-2 to the Nth light-emitting circuits 130-N can be directly applied to the explanation for the circuit configuration of the first light-emitting circuit 130-1.

[0109] As shown in Figure 3, the voltage generation circuit 150 can provide a reference voltage VREF to the reference current generation circuit 110. The voltage generation circuit 150 is connected to the reference current generation circuit 110 via the X node. Therefore, the voltage generation circuit 150 can output the reference voltage VREF to the reference current generation circuit 110 via the X node. The reference current generation circuit 110 can generate a reference current IREF based on the reference voltage VREF.

[0110] The voltage generation circuit 150 may include a first transistor T31, a reference voltage regulation circuit, control switches 151-1, 151-2, and the like.

[0111] The first transistor T31 is connected to a diode; that is, the gate and drain of the first transistor are electrically connected. The first transistor T31 may include, but is not limited to, a PMOS transistor.

[0112] The reference voltage adjustment circuit is connected to the first transistor T31 and can adjust the reference voltage VREF. The reference voltage adjustment circuit may include a second transistor T32-1 and a selector switch 156-1. The second transistor T32-1 may be connected to a diode and may include a PMOS transistor.

[0113] The drawing shows one second transistor T32-1 and one selector switch 156-1, but multiple second transistors may be connected in parallel with each other, and multiple selector switches may be connected in series with multiple second transistors. Hereafter, T32-1 will be used as a reference numeral for multiple second transistors, and 156-1 will be used as a reference numeral for multiple selector switches.

[0114] The gates of multiple second transistors T32-1 may be connected in common. In this case, the multiple second transistors T32-1 can be turned on / off in response to the control signal E11. By selectively turning on the multiple second transistors T32-1, at least one of the multiple second transistors T32-1 is selected. The reference voltage VREF is adjusted using the selected at least one transistor T32-1 and the first transistor T31.

[0115] Multiple 2 transistors T32-1 in the reference voltage regulation circuit and multiple 2 transistors T22-1 in the reference current regulation circuit 115 can form a current mirror circuit.

[0116] The drawing shows one second transistor T22-1 and one selector switch 112-1, but multiple second transistors may be connected in parallel with each other, and multiple selector switches may be connected in series with multiple second transistors. Hereafter, T22-1 will be used as a reference numeral for multiple second transistors, and 112-1 will be used as a reference numeral for multiple selector switches.

[0117] The gates of the multiple second transistors T32-1 in the reference voltage regulation circuit and the gates of the multiple second transistors T22-1 in the reference current regulation circuit 115 may be connected in common to the X node.

[0118] In this case, a reference voltage VREF, regulated by at least one second transistor selected from multiple second transistors T32-1 and the first transistor T31, is output to the X node. At least one constant current is generated by at least one second transistor T22-1 selected from multiple second transistors T22-1. If the reference voltage VREF is regulated to be different, at least one constant current is also changed to be different.

[0119] On the other hand, each of the multiple selection switches 156-1 may be connected in series with each of the multiple second transistors T32-1. Each of the multiple selection switches 156-1 may include a third transistor T33-1. The third transistor T33-1 may include, but is not limited to, a PMOS transistor. For example, each of the multiple third transistors T33-1 may be connected in series with each of the multiple second transistors T32-1 between the third power supply line 143 and each of the multiple second transistors T32-1.

[0120] On the other hand, the first transistor T31 may have a predetermined diode voltage. Multiple second transistors T32-1 may have the same diode voltage as each other. Multiple second transistors T32-1 may have different diode voltages as each other. The diode voltage may be the threshold voltage of the second transistor T32-1, but is not limited to this.

[0121] Each of the multiple third transistors T33-1 is connected in series with each of the multiple second transistors T32-1, and a reference voltage VREF determined by at least one 2-1 transistor selected from the multiple second transistors T32-1 and the first transistor T31 in response to the selective turn-on of the multiple third transistors T33-1 is output via the G node. The reference voltage VREF may be generated by voltage distribution of the diode voltage of the first transistor T31 and the diode voltage of the selected at least one second transistor T32-1, but is not limited to this.

[0122] On the other hand, control switches 151-1 and 151-2 can control the on / off operation of the display. Control switches 151-1 and 151-2 can control the operation of the voltage generation circuit 150, the reference current generation circuit 110, and the light-emitting circuits 130-1 to 130-N, respectively.

[0123] The control switches 151-1 and 151-2 may include a first control transistor T41 and a second control transistor T42.

[0124] The first control transistor T41 is connected between the first transistor T31 and the fourth power supply line 144, and the second control transistor T42 is connected between the third power supply line 143 and the first transistor T31. The third power supply voltage PVDD is supplied to the third power supply line 143, and the fourth power supply voltage PVSS is supplied to the fourth power supply line 144. The third power supply voltage PVDD may be greater than the fourth power supply voltage PVSS. The second power supply voltage and the fourth power supply voltage PVSS may be grounded, i.e., 0V, but are not limited to this. The third power supply voltage PVDD may be less than the first power supply voltage.

[0125] The first control transistor T41 may include an NMOS transistor, and the second control transistor T42 may include a PMOS transistor. The gates of the first control transistor T41 and the second control transistor T42 may be connected in common.

[0126] For example, in response to a high-level control signal EC, the first control transistor T41 turns on and the second control transistor T42 turns off, thereby performing the display operation. In this case, a reference voltage VREF is output from the voltage generation circuit 150 to the X node, the reference current generation circuit 110 generates a reference current IREF based on the reference voltage VREF, and the first light-emitting circuit 130-1 generates a first light-emitting current IEM1 based on the reference current IREF. As a result, the first light-emitting element 120-1 emits light according to the first light-emitting current IEM1, and an image is displayed.

[0127] For example, in response to a low-level control signal EC, the first control transistor T41 turns off and the second control transistor T42 turns on, thereby stopping the display operation. In such a case, the voltage generation circuit 150 does not operate, so the reference voltage VREF is not output to the X node. As a result, the reference current IREF of the reference current generation circuit 110 and the first light-emitting current IEM1 of the first light-emitting circuit 130-1 are not generated, and therefore the image is not displayed.

[0128] Meanwhile, the reference current generation circuit 110 is connected to the first subpixel SP-1. The reference current IREF generated or regulated by the reference current generation circuit 110 is copied to the first subpixel SP-1, generating the first light-emitting current IEM1 in the first subpixel SP-1, which in turn allows the first light-emitting element 120-1 to emit light.

[0129] In the embodiment, the reference current generation circuit 110 may include a reference current adjustment circuit 115 that adjusts the reference current IREF. When the reference current IREF is adjusted by the reference current adjustment circuit 115, the first light-emitting circuit 130-1 can generate (or adjust) the first light-emitting current IEM1 using the adjusted reference current IREF. For example, if the reference current IREF is adjusted to be larger, the first light-emitting current IEM1 can be increased in accordance with the adjusted reference current IREF. For example, if the reference current IREF is adjusted to be smaller, the first light-emitting current IEM1 can be decreased in accordance with the adjusted reference current IREF.

[0130] The brightness of the first light-emitting element 120-1 may be determined by the first light-emitting current IEM1. That is, the larger the first light-emitting current IEM1, the higher the brightness of the first light-emitting element 120-1 can be. For example, the brightness of the first light-emitting element 120-1 may decrease due to differences in manufacturing characteristics or environmental differences, causing the first light-emitting current IEM1 to decrease. In such cases, the brightness of the first light-emitting element 120-1 can be increased by adjusting the reference current IREF in the reference current adjustment circuit 115 to increase the first light-emitting current IEM1 of the first light-emitting circuit 130-1.

[0131] The reference current control circuit 115 may include a constant current source 111-1 and a selector switch 112-1. Although the drawing shows one constant current source 111-1 and one selector switch 112-1, multiple constant current sources may be connected in parallel, and multiple selector switches may each be connected in series to multiple constant current sources. Hereafter, 111-1 is used as a reference numeral in the drawing to refer to multiple constant current sources, and 112-1 is used as a reference numeral in the drawing to refer to multiple selector switches.

[0132] Multiple constant current sources 111-1 may each be sources that generate a constant current. Multiple constant current sources 111-1 may be connected in parallel to each other between the third power supply line 143 and the first transistor T21.

[0133] Multiple constant current sources 111-1 and multiple selection switches 112-1 are electrically connected to each other. Multiple constant current sources 111-1 are selected by switching the multiple selection switches 112-1. Each of the multiple constant current sources 111-1 includes a second transistor T22-1, and each of the multiple selection switches 112-1 may include a third transistor T23-1. The second transistor T22-1 and the third transistor T23-1 may be PMOS transistors, but are not limited to them.

[0134] For example, multiple second transistors T22-1 may be connected in parallel to each other between the third power supply line 143 and the first transistor T21.

[0135] In such a case, the gates of multiple second transistors T22-1 may be connected in common. Multiple second transistors T22-1 can generate multiple constant currents based on a reference voltage VREF input to their gates. These multiple constant currents may be identical or different.

[0136] In this case, the generation of multiple constant currents may be determined according to the turn-on / turn-off of multiple selection switches 112-1.

[0137] Each of the multiple selection switches 112-1 may be connected in series with each of the multiple second transistors T22-1. Each of the multiple selection switches 112-1 may include a third transistor T23-1. The third transistor T23-1 may include, but is not limited to, a PMOS transistor.

[0138] For example, multiple third transistors T23-1 may be connected in series with multiple second transistors T22-1 between the third power supply line 143 and the first transistor T21. In such a case, multiple constant currents are generated in the multiple second transistors T22-1 in response to the turn-on of the multiple third transistors T23-1.

[0139] A reference current IREF is generated using at least one constant current selected from multiple constant currents. For example, the reference current IREF can be increased as the number of selected constant currents increases. The reference current IREF can be used to generate the first light-emitting current IEM1 in the first light-emitting circuit 130-1.

[0140] Multiple third transistors T23-1 can be turned on / off in response to multiple selection signals C21. Since the multiple third transistors T23-1 are PMOS transistors, each of the multiple third transistors T23-1 can be turned on when the multiple selection signals C21 are at a low level, and each of the multiple third transistors T23-1 can be turned off when the multiple selection signals C21 are at a high level.

[0141] The drawing shows four constant current sources 111-1 and four selector switches 112-1, but more constant current sources and selector switches may be provided.

[0142] On the other hand, the reference current generation circuit 110 may include a first transistor T21 and third control switches 113-1 and 113-2 connected to the first transistor T21.

[0143] The first transistor T21 is connected to a diode. That is, the gate and drain of the first transistor T21 may be connected in common. A reference current IREF determined by multiple constant currents generated by multiple constant current sources 111-1 can flow through the first transistor T21.

[0144] The first transistor T21 of the reference current generation circuit 110 can form a current mirror circuit with the first transistor T11 of the first light-emitting circuit 130-1. In this case, the gate of the first transistor T21 of the reference current generation circuit 110 and the gate of the first transistor T11 of the first light-emitting circuit 130-1 may be connected to a common G node.

[0145] The third control switches 113-1 and 113-2 are connected to the first transistor T21 and can control the on / off state of the reference current IREF. Turning the reference current IREF on means that the reference current IREF flows through the first transistor T21, and turning the reference current IREF off means that the reference current IREF does not flow through the first transistor T21.

[0146] The third control switch may include a third-first control switch 113-1 and a third-second control switch 113-2. The third-first control switch 113-1 is connected between the first transistor T21 and the second power supply line 142, and the third-second control switch 113-2 is connected between the reference current adjustment circuit 115 and the first transistor T21.

[0147] The third-first control switch 113-1 includes a sixth transistor T24, and the third-second control switch 113-2 may include a seventh transistor T25. The sixth transistor T24 may include an NMOS transistor, and the seventh transistor T25 may include a PMOS transistor.

[0148] The third-first control switch 113-1 and the third-second control switch 113-2 can be simultaneously turned on or off by control signals D1 and D2. For example, if control signal D1 is at a high level and control signal D2 is at a low level, both the third-first control switch 113-1 and the third-second control switch 113-2 can be turned on. For example, if control signal D1 is at a low level and control signal D2 is at a high level, both the third-first control switch 113-1 and the third-second control switch 113-2 can be turned off.

[0149] When the third-first control switch 113-1 and the third-second control switch 113-2 are open due to control signals D1 and D2, the reference current IREF does not flow through the first transistor T21, which can be interpreted as the reference current IREF being off. When the third-first control switch 113-1 and the third-second control switch 113-2 are closed due to control signals D1 and D2, the reference current IREF flows through the first transistor T21, which can be interpreted as the reference current IREF being on. The time interval during which the reference current IREF flows through the first transistor T21 can be defined as the on-interval. The time interval during which the reference current IREF does not flow through the first transistor T21 can be defined as the off-interval.

[0150] For example, the circuit may be divided into on-periods and off-periods according to its cycle. The period may be, for example, one frame, but is not limited to this. During the on-period, the third-first control switch 113-1 and the third-second control switch 113-2 are in the closed state, so the reference current IREF can flow through the first transistor T21. During the off-period, the third-first control switch 113-1 and the third-second control switch 113-2 are in the open state, so the reference current IREF does not flow through the first transistor T21.

[0151] On the other hand, the reference current generation circuit 110 may include a first control switch 116, a second control switch 117, and third control switches 113-1 and 113-2.

[0152] The first control switch 116 is connected between the first transistor T21 and the second power supply line 142, and the second control switch 117 is connected between the first transistor T21 and the measurement line 145.

[0153] The first control switch 116 may include a fourth transistor T26, and the second control switch 117 may include a fifth transistor T27. The fourth transistor T26 and the fifth transistor T27 may include, but are not limited to, NMOS transistors.

[0154] For example, the first control switch 116 can be turned on and the second control switch 117 can be turned off. In such a case, when the first transistor T21 is connected to the second power line 142 and the third control switches 113-1 and 113-2 are turned on, a reference current IREF is generated, which is determined based on at least one constant current generated by the reference current adjustment circuit 115.

[0155] As another example, the first control switch 116 can be turned off and the second control switch 117 can be turned on. In such a case, when the first transistor T21 is connected to the measurement line 145 and the third control switches 113-1 and 113-2 are turned on, the generated reference current IREF is output via the measurement line 145.

[0156] On the other hand, the first subpixel SP-1 may include a first light-emitting circuit 130-1 and a first light-emitting element 120-1. The first light-emitting element 120-1 may be included in the first light-emitting circuit 130-1.

[0157] The first light-emitting circuit 130-1 can drive the first light-emitting element 120-1 to emit light. To this end, the first light-emitting circuit 130-1 generates a first light-emitting current IEM1, and the first light-emitting element 120-1 can emit light due to the generated first light-emitting current IEM1. The first light-emitting current IEM1 may be a constant current.

[0158] The first light-emitting current IEM1 is generated in accordance with the reference current IREF adjusted by the reference current generation circuit 110. That is, if the reference current IREF increases, the first light-emitting current IEM1 can also increase.

[0159] The first light-emitting circuit 130-1 may include a first transistor T11, a fifth control switch SW11, SW12-1, SW12-2, etc.

[0160] The first transistor T11 of the first light-emitting circuit 130-1 is connected to the first light-emitting element 120-1. The first light-emitting element 120-1 and the first light-emitting circuit 130-1 may be connected in series between the first power supply line 141 and the second power supply line 142. For example, the anode electrode of the first light-emitting element 120-1 is electrically connected to the first power supply line 141, the cathode electrode of the first light-emitting element 120-1 is electrically connected to the drain of the first transistor T11, and the source of the first transistor T11 is electrically connected to the second power supply line 142.

[0161] The first transistor T11 can generate a first light-emitting current IEM1. The first light-emitting current IEM1 is generated based on a reference current IREF generated by a reference current generation circuit 110. The first transistor T11 can generate a first light-emitting current IEM1 corresponding to the reference current IREF generated by the reference current generation circuit 110. The first transistor T11 can generate a first light-emitting current IEM1 that is a copy of the reference current IREF. When the first light-emitting current IEM1 is generated by the first transistor T11, the first light-emitting element 120-1 can emit light with the first light-emitting current IEM1.

[0162] A current mirror circuit may be formed by the first transistor T21 of the reference current generation circuit 110 and the first transistor T11 of the first light-emitting circuit 130-1. In the current mirror circuit, a first light-emitting current IEM1 is generated in the first transistor T11 of the first light-emitting circuit 130-1 in accordance with the reference current IREF flowing through the first transistor T21 of the reference current generation circuit 110. At this time, the first light-emitting current IEM1 may be the same as the reference current IREF, or it may be larger.

[0163] In the embodiment, the first transistor T21 of the reference current generation circuit 110 and the first transistor T11 of the first light-emitting circuit 130-1 may be MOS transistors, but are not limited to this. The first transistor T21 of the reference current generation circuit 110 and the first transistor T11 of the first light-emitting circuit 130-1 may be MOS transistors of the same conductivity type. The first transistor T21 of the reference current generation circuit 110 and the first transistor T11 of the first light-emitting circuit 130-1 may be NMOS transistors, but are not limited to this.

[0164] The first transistor T21 of the reference current generation circuit 110 is connected to a diode, and the gate of the first transistor T21 of the reference current generation circuit 110 and the gate of the first transistor T11 of the first light-emitting circuit 130-1 may be commonly connected to the G node. In addition, the source of the first transistor T21 of the reference current generation circuit 110 and the source of the first transistor T11 of the first light-emitting circuit 130-1 may be commonly connected to the second power supply line 142.

[0165] In this case, the reference current IREF flowing through the reference current generation circuit 110 can be expressed by equation 1, and the first light-emitting current IEM1 flowing through the first light-emitting circuit 130-1 can be expressed by equation 2.

number

number

[0166] According to Equation 1, the voltage at the G node V G This is calculated. In other words, the first transistor T21 of the reference current generation circuit 110 may be a conversion element that converts the reference current IREF into the voltage of the G node.

[0167] The first transistor T11 of the first light-emitting circuit 130-1 may be a conversion element that converts the voltage at the G node into the first light-emitting current IEM1.

[0168] From equations 1 and 2, the process constants μ and C are found in the first transistor T21 of the reference current generation circuit 110 and the first transistor T11 of the first light-emitting circuit 130-1. ox and aspect ratio W D / L D , W E / L E If they are the same, the reference current IREF and the first light-emitting current IEM1 can be the same. In such a case, the reference current IREF is copied as is and generated as the first light-emitting current IEM1 in the first light-emitting circuit 130-1.

[0169] In contrast to this, in the first transistor T21 of the reference current generating circuit 110 and the first transistor T11 of the first light emitting circuit 130-1, the process constant μ, C ox are the same, but the aspect ratio W D / L D , W E / L E are different, the reference current IREF and the first light emitting current IEM1 will be different. For example, the aspect ratio W of the first transistor T11 of the first light emitting circuit 130-1 E / L E is larger than the aspect ratio W of the first transistor T21 of the reference current generating circuit 110 D / L D , the first light emitting current IEM1 can be larger than the reference current IREF. For convenience, the aspect ratio W of the first transistor T21 of the reference current generating circuit 110 D / L D is named a first aspect ratio, and the aspect ratio W of the first transistor T11 of the first light emitting circuit 130-1 E / L E can be named a second aspect ratio.

[0170] Therefore, by designing the first aspect ratio W D / L D to be small, a small reference current IREF is generated in the reference current generating circuit 110. This reduces the burden for generating the reference current IREF, reduces the size of the reference current generating circuit 110, and can save power consumption.

[0171] In addition, by designing the second aspect ratio W E / L E to be large, a large first light emitting current IEM1 is generated in the first light emitting circuit 130-1. Accordingly, the first light emitting element 120-1 emits light by the large first light emitting current IEM1, so that the contrast ratio is improved and high luminance can be implemented.

[0172] On the other hand, the fifth control switches SW11, SW12-1, and SW12-2 of the first light-emitting circuit 130-1 are connected to the first transistor T11 and can control the on / off state of the first light-emitting current IEM1. The fifth control switches SW11, SW12-1, and SW12-2 may include the fifth-first control switch SW11, the fifth-second control switch SW12-1, and the fifth-third control switch SW12-2. The fifth-first control switch SW11 may include an NMOS transistor, and the fifth-second control switch SW12-1 and the fifth-third control switch SW12-2 may include PMOS transistors, but are not limited to these.

[0173] The 5-1 control switch SW11 is connected between the first transistor T11 and the second power line 142, the 5-2 control switch SW12-1 is connected between the first light-emitting element 120-1 and the first transistor T11, and the 5-3 control switch SW12-2 is connected to the third power line 143. The gates of the 5-2 control switch SW12-1 and the 5-3 control switch SW12-2 may be connected in common.

[0174] The 5-1 control switch SW11 includes the 6th transistor T12-1, the 5-2 control switch SW12-1 includes the 7th transistor T13-1, and the 5-3 control switch SW12-2 may include the 8th transistor T13-2.

[0175] The sixth transistor T12-1 may be an NMOS transistor, and the seventh transistor T13-1 and the eighth transistor T13-2 may be PMOS transistors.

[0176] The 5-1 control switch SW11, the 5-2 control switch SW12-1, and the 5-3 control switch SW12-2 can be simultaneously turned on or off by control signals C11 and C12. The 5-2 control switch SW12-1 and the 5-3 control switch SW12-2 can be simultaneously turned on / off by control signal C12.

[0177] When the 5-1st control switch SW11 and the 5-2nd control switch SW12-1 are open due to control signals C11 and C12, the first light-emitting current IEM1 does not flow through the first transistor T11, which can be interpreted as the first light-emitting current IEM1 being turned off. When the 5-1st control switch SW11 and the 5-2nd control switch SW12-1 are closed due to control signals C11 and C12, the first light-emitting current IEM1 flows through the first transistor T11, which can be interpreted as the first light-emitting current IEM1 being turned on. The time interval during which the first light-emitting current IEM1 flows through the first transistor T11 can be defined as the on-interval. The time interval during which the first light-emitting current IEM1 does not flow through the first transistor T11 can be defined as the off-interval.

[0178] For example, the period may be divided into an ON section (or light-emitting section) and an OFF section (non-light-emitting section). The period may be, for example, one frame, but is not limited to this. During the ON section, the 5-1 control switch SW11 and the 5-2 control switch SW12-1 are in the closed state, so the first light-emitting current IEM1 flows to the first transistor T11 and the first light-emitting element 120-1 can emit light. During the OFF section, the 5-1 control switch SW11 and the 5-2 control switch SW12-1 are in the open state, so the first light-emitting current IEM1 does not flow to the first transistor T11 and the first light-emitting element 120-1 does not emit light.

[0179] For the sake of clarity, the ON period in which the reference current IREF flows through the first transistor T21 of the reference current generation circuit 110 may be named the first ON period, and the ON period in which the first light-emitting current IEM1 flows through the first transistor T11 of the first light-emitting circuit 130-1 may be named the second ON period.

[0180] If the third control switches 113-1 and 113-2 of the reference current generation circuit 110 are closed in response to control signals D1 and D2, the reference current IREF can flow through the first transistor T21 of the reference current generation circuit 110 during the first ON period. If the fifth control switches SW11, SW12-1 and SW12-2 of the first light-emitting circuit 130-1 are closed in response to control signals C11 and C12, the first light-emitting current IEM1 can flow through the first transistor T11 of the first light-emitting circuit 130-1 during the second ON period.

[0181] The second on-section may be contained within the first on-section. The width of the second on-section may be greater than the width of the first on-section. The rising time of the first on-section may be faster than the rising time of the second on-section, and the falling time of the first on-section may be slower than the falling time of the second on-section.

[0182] On the other hand, the first light-emitting circuit 130-1 may include digital storage. The digital storage can generate control signals C11 and C12 for switching the fifth control switches SW11, SW12-1, and SW12-2 of the first light-emitting circuit 130-1 using digital data and program signals.

[0183] In response to control signals C11 and C12, the fifth control switches SW11, SW12-1, and SW12-2 are turned on or off. When the fifth control switches SW11, SW12-1, and SW12-2 are closed during the second on-interval in response to control signals C11 and C12, a first light-emitting current IEM1 is generated in the first transistor T11, and the first light-emitting element 120-1 can emit light due to the generated first light-emitting current IEM1.

[0184] Since the fifth control switches SW11, SW12-1, and SW12-2 remain closed during the second ON period, the first light-emitting element 120-1 can emit light during the second ON period.

[0185] The second ON interval may, but is not limited to, be determined by a program signal. The program signal may include grayscale information for determining the second ON interval. This generates control signals C11 and C12 having a second ON interval based on the digital data and the program signal. For example, the larger the grayscale, the larger the second ON interval can be. Therefore, by changing the width of the second ON interval, an image with the desired grayscale can be displayed.

[0186] On the other hand, control signals D1 and D2 for maintaining the third control switches 113-1 and 113-2 of the reference current generation circuit 110 in a closed state during the first ON interval may be provided from an external source, such as a host, data processing device, processor, or controller.

[0187] In this embodiment, a constant current, the first light-emitting current IEM1, is generated in the first transistor T11 of the first light-emitting circuit 130-1 in response to the reference current IREF generated in the reference current generation circuit 110. At this time, the second ON interval is determined or adjusted based on digital data and program signals, and the first light-emitting element 120-1 emits light during the second ON interval, thereby displaying images with different gradations. For example, the longer the second ON interval, the higher the gradation of the displayed image.

[0188] On the other hand, the first light-emitting circuit 130-1 may include a first control switch 131-1, a second control switch 132-1, a third control switch 133-1, and a fourth control switch 134-1. The first to fourth control switches 131-1 to 134-1 can be turned on / off in response to the first control signal CSA to the fourth control signal CSD, respectively.

[0189] The first control switch 131-1 is connected between the first transistor T11 and the second power supply line 142, and the second control switch 132-1 is connected between the first transistor T11 and the measurement line 145.

[0190] The third control switch 133-1 is connected between the first light-emitting element 120-1 and the first transistor T11, and the fourth control switch 134-1 is connected between the third power supply line 143 and the first transistor T11.

[0191] The first control switch 131-1 may include a second transistor T14, and the second control switch 132-1 may include a third transistor T15. The third control switch 133-1 may include a fourth transistor T16, and the fourth control switch 134-1 may include a fifth transistor T17.

[0192] The second transistor T14 and the third transistor T15 may, but are not limited to, NMOS transistors. The second transistor T14 can be turned on in response to a high-level first control signal CSA. The third transistor T15 can be turned on in response to a high-level second control signal CSB.

[0193] The fourth transistor T16 and the fifth transistor T17 may, but are not limited to, PMOS transistors. The fourth transistor T16 can be turned on in response to a low-level third control signal CSC. The fifth transistor T17 can be turned on in response to a low-level fourth control signal CSD.

[0194] On the other hand, the first control switch 131-1 of the first light-emitting circuit 130-1 and the first control switch 116 of the reference current generation circuit 110 can be turned on or turned off simultaneously by the first control signal CSA. If the first control switch 131-1 of the first light-emitting circuit 130-1 and the first control switch 116 of the reference current generation circuit 110 are NMOS transistors, the first control switch 131-1 of the first light-emitting circuit 130-1 and the first control switch 116 of the reference current generation circuit 110 can be turned on simultaneously in response to a high level of the first control signal CSA.

[0195] The second control signal CSB can simultaneously turn on or turn off the second control switch 132-1 of the first light-emitting circuit 130-1 and the second control switch 117 of the reference current generation circuit 110. If the second control signal CSB is an NMOS transistor, the second control switch 132-1 of the first light-emitting circuit 130-1 and the second control switch 117 of the reference current generation circuit 110 can simultaneously turn on in response to a high level of the second control signal CSB.

[0196] For example, when the first control switch 131-1 is turned on and the second control switch 132-1 is turned off, the first transistor T11 is connected to the second power supply line 142, but is electrically disconnected from the measurement line 145. When the third control switch 133-1 and the fifth control switches SW11, SW12-1, and SW12-2 are turned on and the fourth control switch 134-1 is turned off, the first light-emitting circuit 130-1 generates the first light-emitting current IEM1.

[0197] As another example, the first control switch 131-1 is turned off and the second control switch 132-1 is turned on, connecting the first transistor T11 to the measurement line 145, but electrically disconnecting it from the second power supply line 142. In this case, the first light-emitting current IEM1 when light is emitted and the non-light-emitting current when light is not emitted are output via the measurement line 145. The first light-emitting current IEM1 may be the current used to emit light from the first light-emitting element 120-1. The non-light-emitting current may be the current generated in the first light-emitting circuit 120-1 between the third power supply line 143 and the second power supply line 142. The non-light-emitting current may be different from the first light-emitting current IEM1.

[0198] For example, when the third control switch 133-1 and the fifth control switches SW11, SW12-1, SW12-2 are turned on and the fourth control switch 134-1 is turned off, the first light-emitting current IEM1 generated by the first transistor T11 of the first light-emitting circuit 130-1 is output via the measurement line 145 between the first power line and the measurement line 145 in order to make the first light-emitting element 120-1 light up. For example, when the third control switch 133-1 is turned off and the fourth control switch 134-1 and the fifth control switches SW11, SW12-1, SW12-2 are turned on, the non-light-emitting current generated by the first transistor T11 of the first light-emitting circuit 130-1 is output via the measurement line 145 between the third power line 143 and the measurement line 145.

[0199] On the other hand, various currents can be measured by turning on / off the first control switches 116 and 2 control switches 117 of the reference current generation circuit 110 and the first control switches 131-1 to 4 control switches 134-1 of the first light-emitting circuit 130-1. These various currents can be measured by the current measurement circuit 170 (170 in Figure 2).

[0200] As a first example, the reference current IREF generated by the reference current generation circuit 110, as shown in equation 3, is measured as I M1 It is measured as follows. [Formula 3] I M1 =IREF

[0201] As a second example, as shown in Equation 4, while a specific light-emitting element is emitting light, the reference current IREF and the specific light-emitting current are measured as I M2 It is measured as follows. [Formula 4] I M2 =IREF+IEM#_ON

[0202] IEM#_ON can indicate the light-emitting current generated by a specific light-emitting circuit (out of multiple light-emitting circuits, 130-1 to 130-N in Figure 2) that is intended to be measured by emitting light from a specific light-emitting element.

[0203] For example, measurement result I M2This may be the sum of the reference current IREF and the specific light-emitting current, but is not limited to this.

[0204] As a third example, as shown in Equation 5, while a specific light-emitting element is not emitting light, the reference current IREF and the specific non-emitting current are measured as I M3 It is measured as follows. [Formula 5] I M3 =IREF+IEM#_OFF

[0205] IEM#_OFF indicates that a specific light-emitting element among multiple light-emitting circuits (130-1 to 130-N in Figure 2) could not be made to emit light, and that the non-emitting current generated by the specific light-emitting circuit being measured is being indicated.

[0206] For example, measurement result I M3 This may be the sum of the reference current IREF and the specific non-luminescent current, but is not limited to this.

[0207] For example, the measurement results I shown in each of equations 3 to 5. M1 , I M2 , I M3 By using this, the reference voltage adjustment circuit of the voltage generation circuit 150 and / or the reference current adjustment circuit 115 of the reference current generation circuit 110 are controlled, thereby adjusting the light emission currents IEM1 to IEMN of each light emission circuit 130-1 to 13-N. This ensures uniformity of current between multiple ICs (first ICs) and improves image quality.

[0208] Measurement results I shown in equations 3 to 5 M1 , I M2 , I M3 The process of obtaining this will be explained in detail with reference to Figures 5 to 7.

[0209] According to the embodiment, since the first light-emitting circuit 130-1 does not have a capacitor, it is not subject to area constraints, and the aperture ratio can be increased, thereby improving brightness.

[0210] According to the embodiment, since a display driver including a converter that converts digital data to analog data is not required, the circuit structure becomes simpler, the occupied area is reduced, and costs can be saved.

[0211] According to the embodiment, by adjusting the reference currents IREF to be different from each other, accurate brightness adjustment is possible at any time.

[0212] According to the embodiment, brightness adjustment between display screens is easily achieved by switching the multiple selection switches 112-1 provided in the reference current adjustment circuit 115.

[0213] According to the embodiment, a voltage generation circuit 150 can provide a plurality of different reference voltages VREF, and a reference current generation circuit 110 can generate a plurality of different reference currents IREF based on each of the plurality of reference voltages VREF. In such a case, a first light-emitting circuit 130-1 can generate a plurality of different first light-emitting currents IEM1 based on the plurality of different reference currents IREF.

[0214] For example, if the voltage generation circuit 150 is equipped with three selection switches 156-1, (2 3-1 ) = 7 different reference voltages VREF are provided. For example, if the reference current adjustment circuit 115 of the reference current generation circuit 110 is equipped with 4 selection switches 112-1, (2 4-1 ) = 15 different reference currents IREF are generated. In this case, each of the first light-emitting circuits 130-1 generates (7 × 15) = 105 different first light-emitting currents IEM1.

[0215] Therefore, by providing transistors T32-1, T33-1, T22-1, and T23-1 in each of the voltage generation circuit 150 and / or reference current generation circuit 110 so that the reference voltage VREF and / or reference current IREF can be adjusted, the desired brightness can be precisely obtained by a number of different first light-emitting currents IEM1, and the image quality can be dramatically improved.

[0216] In this embodiment, the measurement line 145 is connected to the reference current generation circuit 110 and a plurality of light-emitting circuits 130-1 to 130-N, and the reference current generated by the reference current generation circuit 110 and the plurality of light-emitting currents IEM1 to IEMN and non-light-emitting currents generated by the plurality of light-emitting circuits 130-1 to 130-N are measured. The voltage generation circuit 150 and the reference current generation circuit 110 are controlled using the currents measured in this way, thereby ensuring uniformity of the light-emitting current between displays and between blocks, i.e., brightness uniformity. Here, a block is a circuit configuration unit as shown in Figure 2, and a plurality of blocks may be provided in the display panel.

[0217] [Lighting Mode]

[0218] Figure 4 illustrates a display device according to a second embodiment operating in light emission mode.

[0219] As shown in Figure 4, the display operation is performed by switching the control switch, and the voltage generation circuit 150, the reference current generation circuit 110, and the light-emitting circuit are activated.

[0220] Specifically, in response to a high-level control signal EC, control switch 151-1 turns on and control switch 151-2 turns off, causing the voltage generation circuit 150 to operate. In response to the turning on / off of multiple selection switches 156-1 of the reference voltage regulation circuit, a threshold voltage of at least one second transistor T32-1 selected and a reference voltage VREF regulated by the first transistor T31 are output.

[0221] On the other hand, in order to operate in light emission mode, the first control switch 116 and the third control switches 113-1 and 113-2 in the reference current generation circuit 110 can be turned on, and the second control switch 117 can be turned off. In this case, the first transistor T21 of the reference current generation circuit 110 is electrically connected to the second power supply line 142, but disconnected from the measurement line 145. As a result, the reference current adjustment circuit 115 of the reference current generation circuit 110 generates a reference current IREF adjusted by at least one or more constant current sources 111-1 selected in response to the turning on / off of a plurality of selection switches 156-1 based on the adjusted reference voltage VREF.

[0222] Furthermore, the first light-emitting circuit 130-1 can turn on the first control switch 131-1, the third control switch 133-1, and the fifth control switches SW11, SW12-1, and SW12-2, while turning off the second control switch 132-1 and the fourth control switch 134-1. In this case, the first transistor T11 of the first light-emitting circuit 130-1 is electrically connected to the second power supply line 142, but disconnected from the measurement line 145. The first transistor T11 of the first light-emitting circuit 130-1 generates a first light-emitting current IEM1 corresponding to the reference current IREF generated in the reference current generation circuit 110, and supplies it to the first light-emitting element 120-1. As a result, the first light-emitting element 120-1 can emit light with the first light-emitting current IEM1.

[0223] Although not shown in the diagram, the first, third, and fifth control switches SW11, SW12-1, and SW12-2 of the second light-emitting circuit (130-2 in Figure 2) to the Nth light-emitting circuit 130-N may be turned on, while the second and fourth control switches may be turned off. As a result, the second to Nth light-emitting elements can emit light through the second to Nth light-emitting currents generated in the second to Nth light-emitting circuits 130-2 to the Nth light-emitting circuit 130-N, respectively.

[0224] [Reference current measurement mode]

[0225] Figure 5 illustrates a display device according to a second embodiment operating in reference current measurement mode.

[0226] As shown in Figure 5, the display operation is performed by switching the control switch, and the voltage generation circuit 150, the reference current generation circuit 110, and the first light-emitting circuit 130-1 are activated. As a result, the reference voltage VREF adjusted by the voltage generation circuit 150 is output via the X node, the reference current generation circuit 110 generates a reference current IREF adjusted using at least one constant current based on the reference voltage VREF, and the first light-emitting circuit 130-1 can generate a first light-emitting current IEM1 corresponding to the reference current IREF in order to emit light from the first light-emitting element 120-1.

[0227] On the other hand, in order to operate in reference current measurement mode, the first control switch 116 in the reference current generation circuit 110 can be turned off, while the second control switch 117 and the third control switches 113-1 and 113-2 can be turned on. In this case, the first transistor T21 of the reference current generation circuit 110 is electrically connected to the measurement line 145, but disconnected from the second power supply line 142. As a result, the reference current IREF is output from the reference current generation circuit 110 via the measurement line 145. The current measurement circuit 170 (170 in Figure 2) can obtain the reference current IREF as a measurement result via the measurement line 145, as shown in Equation 3.

[0228] Furthermore, the fifth control switches SW11, SW12-1, and SW12-2 can be turned off in the first light-emitting circuit 130-1. In this case, the first light-emitting element 120-1 and the third power supply line 143 are electrically disconnected from the second power supply line 142 and the measurement line 145, so the first light-emitting current and non-light-emitting current are not generated or output via the measurement line 145. At this time, the first control switches 131-1 to the fourth control switches 134-1 can be turned on or turned off.

[0229] Although not shown in the diagram, the fifth control switches SW11, SW12-1, and SW12-2 of the second light-emitting circuit (130-2 in Figure 2) to the Nth light-emitting circuit 130-N can be turned off. As a result, the second light-emitting current to the Nth light-emitting current and non-light-emitting current are not generated in each of the second light-emitting circuits 130-2 to the Nth light-emitting circuit 130-N, or they are not output via the measurement line 145.

[0230] [Emitting current measurement mode]

[0231] Figure 6 illustrates a display device according to a second embodiment operating in light emission current measurement mode.

[0232] As shown in Figure 6, the display operation is performed by switching the control switch, and the voltage generation circuit 150, the reference current generation circuit 110, and the first light-emitting circuit 130-1 are activated. As a result, the reference voltage VREF regulated by the voltage generation circuit 150 is output via the X node, the reference current generation circuit 110 generates a reference current IREF regulated by at least one constant current based on the reference voltage VREF, and the first light-emitting circuit 130-1 can generate a first light-emitting current IEM1 corresponding to the reference current IREF in order to emit light from the first light-emitting element 120-1.

[0233] On the other hand, in order to operate in light emission current measurement mode, the first control switch 116 in the reference current generation circuit 110 can be turned off, while the second control switch 117 and the third control switches 113-1 and 113-2 can be turned on. In this case, the first transistor T21 of the reference current generation circuit 110 is electrically connected to the measurement line 145, but disconnected from the second power supply line 142. As a result, the reference current IREF generated by the reference current generation circuit 110 is output via the measurement line 145.

[0234] Furthermore, in the first light-emitting circuit 130-1, the first control switch 131-1 and the fourth control switch 134-1 can be turned off, while the second control switch 132-1, the third control switch 133-1, and the fifth control switches SW11, SW12-1, and SW12-2 can be turned on. The first light-emitting circuit 130-1 may also be the light-emitting circuit to be measured. In this case, the first transistor T11 is connected to the measurement line 145, but is electrically disconnected from the second power supply line 142. As a result, the first light-emitting current IEM1 generated in the first light-emitting circuit 130-1 is output via the measurement line 145.

[0235] The remaining light-emitting circuits that are not being measured, namely the fifth control switches SW11, SW12-1, and SW12-2 of the second to the Nth light-emitting circuits, can be turned off. Therefore, the second to the Nth light-emitting currents and non-light-emitting currents are not generated in each of the second to the Nth light-emitting circuits 130-2 to the Nth light-emitting circuits 130-N, or they are not output via the measurement line 145.

[0236] As a result, the reference current IREF generated (or adjusted) by the reference current generation circuit 110 and the first light-emitting current IEM1 generated (or adjusted) by the first light-emitting circuit 130-1 are output via the measurement line 145. The current measurement circuit 170 (170 in Figure 2) can obtain the sum of the reference current IREF and the first light-emitting current IEM1 as a measurement result via the measurement line 145, as shown in Equation 4. In such a case, the first light-emitting current IEM1 generated by the first light-emitting circuit 130-1 is measured by subtracting the measurement result shown in Equation 3 from the measurement result shown in Equation 4. Such calculations may be performed in the current measurement circuit 170 (170 in Figure 2) or the current control circuit 180, but are not limited to these.

[0237] [Non-luminescent current measurement mode]

[0238] Figure 7 illustrates a display device according to a second embodiment operating in non-luminescence current measurement mode.

[0239] As shown in Figure 7, the display operation is performed by switching the control switch, and the voltage generation circuit 150, the reference current generation circuit 110, and the first light-emitting circuit 130-1 are activated. As a result, the reference voltage VREF regulated by the voltage generation circuit 150 is output via the X node, the reference current generation circuit 110 generates a reference current IREF regulated using at least one constant current based on the reference voltage VREF, and the first light-emitting circuit 130-1 can generate a first light-emitting current IEM1 corresponding to the reference current IREF in order to emit light from the first light-emitting element 120-1.

[0240] On the other hand, in order to operate in non-luminescent current measurement mode, the first control switch 116 in the reference current generation circuit 110 can be turned off, while the second control switch 117 and the third control switches 113-1 and 113-2 can be turned on. In this case, the first transistor T21 of the reference current generation circuit 110 is electrically connected to the measurement line 145, but disconnected from the second power supply line 142. As a result, the reference current IREF generated by the reference current generation circuit 110 is output via the measurement line 145.

[0241] Furthermore, in the first light-emitting circuit 130-1, the first control switch 131-1 and the third control switch 133-1 are turned off, while the second control switch 132-1, the fourth control switch 134-1, and the fifth control switches SW11, SW12-1, and SW12-2 are turned on. The first light-emitting circuit 130-1 may be the light-emitting circuit to be measured. In this case, the first transistor T11 is connected to the measurement line 145, but is electrically disconnected from the second power supply line 142. As a result, the non-emitting current INEM generated by the first transistor T11 of the first light-emitting circuit 130-1 is output via the measurement line 145 between the third power supply line 143 and the measurement line 145. At this time, the third control switch 133-1 is turned off, so the first light-emitting element 120-1 does not emit light.

[0242] The remaining light-emitting circuits that are not being measured, namely the fifth control switches SW11, SW12-1, and SW12-2 of the second to the nth light-emitting circuits, can be turned off. Therefore, the second to the nth light-emitting currents and the non-light-emitting current INEM are not generated or output via the measurement line 145 in each of the second to the nth light-emitting circuits 130-2 to the nth light-emitting circuits 130-N.

[0243] As a result, the reference current IREF generated (or adjusted) by the reference current generation circuit 110 and the non-emitting current INEM generated (or adjusted) by the first light-emitting circuit 130-1 are output via the measurement line 145. The current measurement circuit 170 (170 in Figure 2) can obtain the sum of the reference current IREF and the non-emitting current INEM as a measurement result via the measurement line 145, as shown in Equation 5. In such a case, the non-emitting current INEM generated by the first light-emitting circuit 130-1 is measured by obtaining the measurement result shown in Equation 3 from the measurement result shown in Equation 5. Such calculations may be performed in the current measurement circuit 170 (170 in Figure 2) or the current control circuit 180, but are not limited to these.

[0244] [Third Embodiment]

[0245] Figure 8 is a block diagram illustrating a display device according to the third embodiment.

[0246] The third embodiment is identical to the second embodiment (Figure 3), except that the first control switch 116 and the second control switch 117 of the reference current generation circuit 110 and the first control switch 131-1 and the second control switch 132-1 of the first light-emitting circuit 130-1 (and the remaining light-emitting circuits) are independently switched and controlled using individual control signals CSC-1, CSC-2, CSD-1, and CSD-2. In the third embodiment, the same drawing numbers are assigned to components having the same circuit structure and function as in the second embodiment (Figure 3), and their detailed descriptions are omitted.

[0247] As shown in Figure 8, the reference current generation circuit 110 may include a first control switch 116, a second control switch 117, a third control switch 113-1, 113-2, etc. The first light emission circuit 130-1 may include a first control switch 131-1, a second control switch 132-1, a third control switch 133-1, a fourth control switch 134-1, a fifth control switch SW11, SW12-1, SW12-2, etc.

[0248] The first control switch 116 and the second control switch 117 of the reference current generation circuit 110, and the first control switch 131-1, the second control switch 132-1, the third control switch 133-1, and the fourth control switch 134-1 of the first light-emitting circuit 130-1 can each be turned on / off independently.

[0249] The first control switch 116 and the second control switch 117 of the reference current generation circuit 110 can be independently turned on / off by the control signals CSE and CSF. The first control switch 116 of the reference current generation circuit 110 can be turned on in response to a high-level control signal CSE. The second control switch 117 of the reference current generation circuit 110 can be turned on in response to a high-level control signal CSF.

[0250] The first control switches 131-1, 2nd control switch 132-1, 3rd control switch 133-1, and 4th control switch 134-1 of the first light-emitting circuit 130-1 can be independently turned on / off by the control signals CSA, CSB, CSC, and CSD. In response to a high-level control signal CSA, the first control switch 131-1 of the first light-emitting circuit 130-1 can be turned on. In response to a high-level control signal CSB, the second control switch 132-1 of the first light-emitting circuit 130-1 can be turned on. In response to a high-level control signal CSC, the third control switch 133-1 of the first light-emitting circuit 130-1 can be turned on. In response to a high-level control signal CSD, the 4th control switch 134-1 of the first light-emitting circuit 130-1 can be turned on.

[0251] Thus, by utilizing a greater number of control signals—CSA, CSB, CSC, CSD, CSE, and CSF—compared to the second embodiment (Figure 3), a wider variety of current measurements becomes possible.

[0252] As an example, as mentioned above, the light-emitting current and non-light-emitting current generated in at least one of the multiple light-emitting circuits (130-1 to 130-N in Figure 2) are measured as shown in Equation 6. M4 It is measured as follows. [Formula 6] I M4 =IEM#

[0253] IEM# can indicate the light-emitting current or non-light-emitting current generated by at least one of the multiple light-emitting circuits 130-1 to 130-N.

[0254] For example, the light-emitting current and non-light-emitting current generated by a single light-emitting circuit are measured as I M4 It is measured as follows.

[0255] For example, the light-emitting current and non-light-emitting current generated by two or more light-emitting circuits are measured as I M4 It is measured as follows. In such cases, the measurement result I M4 This may be the sum of the light-emitting currents generated by two or more light-emitting circuits, or the sum of the non-light-emitting currents generated by two or more light-emitting circuits.

[0256] [Reference current measurement mode during illumination]

[0257] Figure 9 illustrates a display device according to a third embodiment, which operates in a reference current measurement mode during light emission.

[0258] As shown in Figure 9, the display operation is performed by switching the control switch, and the voltage generation circuit 150, the reference current generation circuit 110, and the first light-emitting circuit 130-1 are activated. As a result, the reference voltage VREF adjusted by the voltage generation circuit 150 is output via the X node, the reference current generation circuit 110 generates a reference current IREF adjusted using at least one constant current based on the reference voltage VREF, and the first light-emitting circuit 130-1 can generate a first light-emitting current IEM1 corresponding to the reference current IREF in order to emit light from the first light-emitting element 120-1.

[0259] On the other hand, in order to operate in the reference current measurement mode during light emission, the first control switch 116 in the reference current generation circuit 110 is turned off, and the second control switch 117 and the third control switches 113-1 and 113-2 can be turned on. In this case, the first transistor T21 of the reference current generation circuit 110 is electrically connected to the measurement line 145, but disconnected from the second power supply line 142. As a result, the reference current IREF is output from the reference current generation circuit 110 via the measurement line 145. The current measurement circuit 170 (170 in Figure 2) can obtain the reference current IREF as a measurement result via the measurement line 145, as shown in Equation 3.

[0260] Furthermore, in the first light-emitting circuit 130-1, the first control switch 131-1, the third control switch 133-1, and the fifth control switches SW11, SW12-1, and SW12-2 can be turned on, while the second control switch 132-1 and the fourth control switch 134-1 can be turned off. In this case, a first light-emitting current IEM1 is generated between the first power line and the second line, produced by the first transistor T11 of the first light-emitting circuit 130-1, in order to make the first light-emitting element 120-1 emit light.

[0261] Although not shown in the diagram, the first, third, and fifth control switches SW11, SW12-1, and SW12-2 of the second light-emitting circuit (130-2 in Figure 2) to the Nth light-emitting circuit 130-N may be turned on, while the second and fourth control switches may be turned off. As a result, the second to Nth light-emitting elements can emit light through the second to Nth light-emitting currents generated in the second to Nth light-emitting circuits 130-2 to the Nth light-emitting circuit 130-N, respectively.

[0262] As shown in Figure 9, even when the first light-emitting element 120-1 emits light normally due to the first light-emitting circuit 130-1, the reference current IREF generated by the reference current generation circuit 110 is measured.

[0263] [Reference current measurement mode when light is not emitted]

[0264] Figure 10 illustrates a display device according to a third embodiment, which operates in a reference current measurement mode when no light is emitted.

[0265] As shown in Figure 10, the display operation is performed by switching the control switch, and the voltage generation circuit 150, the reference current generation circuit 110, and the first light-emitting circuit 130-1 are activated. As a result, the reference voltage VREF regulated by the voltage generation circuit 150 is output via the X node, the reference current generation circuit 110 generates a reference current IREF regulated by at least one constant current based on the reference voltage VREF, and the first light-emitting circuit 130-1 can generate a first light-emitting current IEM1 corresponding to the reference current IREF in order to emit light from the first light-emitting element 120-1.

[0266] On the other hand, in order to operate in the reference current measurement mode during light emission, in the reference current generation circuit 110, the first control switch 116 is turned off, and the second control switch 117 and the third control switches 113-1, 113-2 can be turned on. In this case, the first transistor T21 of the reference current generation circuit 110 is electrically connected to the measurement line 145, but is disconnected from the second power supply line 142. Accordingly, the reference current IREF is output from the reference current generation circuit 110 via the measurement line 145. The current measurement circuit 170 (170 in FIG. 2) can obtain the reference current IREF as a measurement result via the measurement line 145, as shown in Mathematical Formula 3.

[0267] Further, in the first light emitting circuit 130-1, the first control switch 131-1, the fourth control switch 134-1, and the fifth control switches SW11, SW12-1, SW12-2 can be turned on, and the second control switch 132-1 and the third control switch 133-1 can be turned off. In this case, the non-emission current INEM is generated by the first transistor T11 of the first light emitting circuit 130-1 between the third power supply line 143 and the second power supply line 142. Since the third control switch 133-1 is turned off, the first light emitting element 120-1 does not emit light.

[0268] Although not illustrated, the second to N-th light emission currents or the non-emission current INEM are generated in each of the second light emitting circuit (130-2 in FIG. 2) to the N-th light emitting circuit 130-N, respectively.

[0269] As illustrated in FIG. 10, even if the first light emitting element 120-1 does not emit light due to the first light emitting circuit 130-1, the reference current IREF generated by the reference current generation circuit 110 is measured.

[0270] From the description of FIGS. 9 and 10, the reference current IREF is measured regardless of whether the first light emitting element 120-1 emits light by the first light emitting circuit 130-1. Accordingly, it can be understood that the reference current IREF is measured regardless of the light emission period or the non-light emission period of one cycle (or one frame).

[0271] [Measurement mode for emission current during light emission]

[0272] Figure 11 illustrates a display device according to a third embodiment, which operates in a light emission current measurement mode during light emission.

[0273] As shown in Figure 11, the display operation is performed by switching the control switch, and the voltage generation circuit 150, the reference current generation circuit 110, and the first light-emitting circuit 130-1 are activated. As a result, the reference voltage VREF adjusted by the voltage generation circuit 150 is output via the X node, the reference current generation circuit 110 generates a reference current IREF adjusted using at least one constant current based on the reference voltage VREF, and the first light-emitting circuit 130-1 can generate a first light-emitting current IEM1 corresponding to the reference current IREF in order to emit light from the first light-emitting element 120-1.

[0274] On the other hand, in order to operate in the reference current measurement mode during light emission, the first control switch 116 and the third control switches 113-1 and 113-2 in the reference current generation circuit 110 can be turned on, and the second control switch 117 can be turned off. In this case, the first transistor T21 of the reference current generation circuit 110 is electrically connected to the second line, but disconnected from the measurement power supply line. As a result, the reference current IREF is generated by the first transistor T21 of the reference current generation circuit 110 between the third power supply line 143 and the second power supply line 142.

[0275] Furthermore, in the first light-emitting circuit 130-1, the first control switch 131-1 and the fourth control switch 134-1 can be turned off, while the second control switch 132-1, the third control switch 133-1, and the fifth control switches SW11, SW12-1, and SW12-2 can be turned on. In this case, the first transistor T11 of the first light-emitting circuit 130-1 is connected to the measurement line 145, but is electrically disconnected from the second power supply line 142. As a result, the first light-emitting current IEM1 generated by the first transistor T11 of the first light-emitting circuit 130-1 is output via the measurement line 145 between the first power supply line and the second line in order to make the first light-emitting element 120-1 light up.

[0276] Although not shown in the diagram, the first and fourth control switches of at least one of the light-emitting circuits from the second light-emitting circuit (130-2 in Figure 2) to the Nth light-emitting circuit 130-N are turned off, and the second, third, and fifth control switches SW11, SW12-1, and SW12-2 are turned on, so that the light-emitting current generated by the light-emitting circuit is output via the measurement line 145.

[0277] As shown in Figure 11, even if the first light-emitting element 120-1 emits light normally due to the first light-emitting circuit 130-1, the first light-emitting current IEM1 generated by the first light-emitting circuit 130-1 is measured as shown in Equation 6. In this case, in Equation 6, IEM# can represent the first light-emitting current IEM1 generated by the first light-emitting circuit 130-1.

[0278] Two or more light-emitting currents generated simultaneously by two or more light-emitting circuits may be measured as a measurement result as shown in Equation 6. In this case, the measurement result may be the sum of the two or more light-emitting currents.

[0279] [Non-emission current measurement mode when no light is emitted]

[0280] Figure 12 illustrates a display device according to a third embodiment that operates in a non-luminescent current measurement mode when no light is emitted.

[0281] As shown in Figure 12, the display operation is performed by switching the control switch, and the voltage generation circuit 150, the reference current generation circuit 110, and the first light-emitting circuit 130-1 are activated. As a result, the reference voltage VREF regulated by the voltage generation circuit 150 is output via the X node, the reference current generation circuit 110 generates a reference current IREF regulated using at least one constant current based on the reference voltage VREF, and the first light-emitting circuit 130-1 can generate a first light-emitting current IEM1 corresponding to the reference current IREF in order to emit light from the first light-emitting element 120-1.

[0282] On the other hand, in order to operate in the reference current measurement mode during light emission, the first control switch 116 and the third control switches 113-1 and 113-2 in the reference current generation circuit 110 can be turned on, and the second control switch 117 can be turned off. In this case, the first transistor T21 of the reference current generation circuit 110 is electrically connected to the second line, but disconnected from the measurement power supply line. As a result, the reference current IREF is generated by the first transistor T21 of the reference current generation circuit 110 between the third power supply line 143 and the second power supply line 142.

[0283] Furthermore, in the first light-emitting circuit 130-1, the first control switch 131-1 and the third control switch 133-1 can be turned off, while the second control switch 132-1, the fourth control switch 134-1, and the fifth control switches SW11, SW12-1, and SW12-2 can be turned on. In this case, the first transistor T11 of the first light-emitting circuit 130-1 is connected to the measurement line 145, but is electrically disconnected from the second power supply line 142. As a result, the non-light-emitting current INEM generated by the first transistor T11 of the first light-emitting circuit 130-1 is output via the measurement line 145 between the third power supply line 143 and the second line.

[0284] Although not shown in the diagram, the first and fourth control switches of at least one of the light-emitting circuits from the second light-emitting circuit (130-2 in Figure 2) to the Nth light-emitting circuit 130-N are turned off, and the second, third, and fifth control switches SW11, SW12-1, and SW12-2 are turned on, so that the non-light-emitting current INEM generated by the light-emitting circuit is output via the measurement line 145.

[0285] As shown in Figure 9, even if the first light-emitting element 120-1 does not emit light due to the first light-emitting circuit 130-1, the non-emitting current INEM generated by the first light-emitting circuit 130-1 is measured as shown in Equation 6. In this case, in Equation 6, IEM# can represent the non-emitting current INEM generated by the first light-emitting circuit 130-1.

[0286] Two or more non-luminescent currents (INEM) generated simultaneously by two or more light-emitting circuits may be measured as a result of the equation shown in Formula 6. In this case, the measurement result may be the sum of the two or more non-luminescent currents (INEM).

[0287] As described above, the voltage generation circuit 150, the reference current generation circuit 110, the first light-emitting circuit 130-1, and the multiple light-emitting elements 120-1 to 120-N can be considered as one block (or module), and the display device or display panel according to the first embodiment may be composed of multiple blocks. As another example, the voltage generation circuit 150 may not be included in multiple blocks but provided separately. In such a case, the voltage generation circuit 150 can be connected in common to multiple blocks and provide a reference voltage VREF to each of the reference current generation circuits 110 of the multiple blocks.

[0288] By using the reference current IREF, luminescent current, or non-luminescent current INEM obtained through the various current measurement operations and methods described above, uniformity of luminescent current between displays and between blocks, i.e., brightness uniformity, can be ensured.

[0289] The detailed description above should not be interpreted restrictively in any way, but should be considered illustrative. The scope of the examples should be determined by a reasonable analysis of the attached claims, and all modifications within the equivalent scope of the examples are included within the scope of the examples.

Claims

1. In a display device containing multiple subpixels, Multiple light-emitting elements are provided in the aforementioned multiple subpixels and connected to a first power line, A reference current generation circuit connected to the third power line, The plurality of subpixels are provided with a plurality of light-emitting circuits connected to the reference current generation circuit and the plurality of light-emitting elements, Includes, The aforementioned reference current generation circuit and the plurality of light-emitting circuits are commonly connected to the second power supply line. The aforementioned reference current generation circuit and the plurality of light-emitting circuits are connected in common to the measurement line, forming a display device.

2. The aforementioned reference current generation circuit is The first transistor and A first control switch is placed between the first transistor and the second power supply line, The display device according to claim 1, further comprising a second control switch between the first transistor and the measurement line.

3. Each of the aforementioned multiple light-emitting circuits is: The first transistor of the reference current generation circuit and the first transistor constituting the mirror circuit, A first control switch is placed between the first transistor and the second power supply line, The display device according to claim 2, further comprising a second control switch between the first transistor and the measurement line.

4. The aforementioned reference current generation circuit is The display device according to claim 3, further comprising a third control switch connected to the first transistor for turning a reference current on and off.

5. Each of the aforementioned multiple light-emitting circuits is: A third control switch is placed between the light-emitting element and the first transistor. A fourth control switch is placed between the third power line and the first transistor, The display device according to claim 4, further comprising a fifth control switch connected to the first transistor for turning the light-emitting current on and off.

6. The display device according to claim 5, wherein in the light emission mode, the first control switch and the third control switch of the reference current generation circuit are turned on and the second control switch is turned off, the plurality of first control switches, the plurality of third control switches and the plurality of fifth control switches of the plurality of light emission circuits are turned on and the plurality of second control switches and the plurality of fourth control switches are turned off.

7. The display device according to claim 6, wherein in the reference current measurement mode, the first control switch of the reference current generation circuit is turned off, the second control switch and the third control switch are turned on, and the fifth control switch of each of the plurality of light-emitting circuits is turned off.

8. The display device according to claim 6, in the light emission current measurement mode, the first control switch of the reference current generation circuit is turned off, the second control switch and the third control switch are turned on, the first control switch and the fourth control switch of the light emission circuit to be measured among the plurality of light emission circuits are turned off, the second control switch, the third control switch and the fifth control switch are turned on, and the fifth control switch of the remaining light emission circuit among the plurality of light emission circuits is turned off.

9. The display device according to claim 6, in a non-luminescent current measurement mode, the first control switch of the reference current generation circuit is turned off, the second control switch and the third control switch are turned on, the first control switch and the third control switch of the luminescent circuit to be measured among the plurality of luminescent circuits are turned off, the second control switch, the fourth control switch and the fifth control switch are turned on, and the fifth control switch of the remaining luminescent circuit among the plurality of luminescent circuits is turned off.

10. The display device according to claim 6, in the reference current measurement mode during light emission, the first control switch of the reference current generation circuit is turned off, the second control switch and the third control switch are turned on, and the first control switch, the third control switch and the fifth control switch of at least one of the plurality of light emission circuits are turned on, and the second control switch and the fourth control switch are turned off.

11. The display device according to claim 6, in the reference current measurement mode when no light is emitted, the first control switch of the reference current generation circuit is turned off, the second control switch and the third control switch are turned on, and the first control switch, the fourth control switch and the fifth control switch of at least one of the plurality of light-emitting circuits are turned on, and the second control switch and the third control switch are turned off.

12. The display device according to claim 6, in the light emission current measurement mode during light emission, the first control switch and the third control switch of the reference current generation circuit are turned on, the second control switch is turned off, the first control switch and the fourth control switch of at least one of the plurality of light emission circuits are turned off, and the second control switch, the third control switch and the fifth control switch are turned on.

13. The display device according to claim 6, in a non-light-emitting current measurement mode when no light is emitted, the first control switch and the third control switch of the reference current generation circuit are turned on, the second control switch is turned off, the first control switch and the third control switch of at least one of the plurality of light-emitting circuits are turned off, and the second control switch, the fourth control switch and the fifth control switch are turned on.

14. A current measuring circuit connected to the aforementioned measuring line, which measures at least one of the reference current or the light-emitting current, The display device according to claim 1, further comprising a current control circuit that controls at least one of a voltage generation circuit or a reference current generation circuit based on the measured current.

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