Display apparatus

Abstract

A 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 the second power line, and the reference current generation circuit and the plurality of light-emitting circuits may be commonly connected to the measurement line.

Description

[Technical Field]

[0001] The embodiment relates to a display device.[Background Art]

[0002] The display market is growing and its application scope is continuously expanding. Along with the expansion of such application scope, the resolution and characteristics of products are becoming more diverse.

[0003] As the specifications of products are diversifying, the driving method for display is also becoming more complex accordingly.

[0004] In the case of a driving IC applied to drive a display device, it is designed accordingly. Therefore, the range of application for the design is limited, so that a driving IC suitable for each product is required when necessary.

[0005] In an existing display device, various methods are applied to secure luminance uniformity. For example, internal compensation is performed by configuring a light-emitting circuit in a pixel (or subpixel), or external compensation is performed in a specific manner.

[0006] Meanwhile, most of the circuit configurations for the operation of the light-emitting circuit have their own capacitors inside the light-emitting circuit, so that constant current characteristics are secured.

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

[0008] As illustrated in FIG. 1, the existing light-emitting circuit includes a driving 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 a scan signal SCAN, a data signal VDATA is supplied to the driving transistor M1 through the scan transistor M2. The driving transistor M1 supplies the light-emitting current corresponding to the data signal VDATA to the light-emitting element ED, so that the light-emitting element ED emits light.

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

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

[0012] Meanwhile, the light-emitting circuit of an active matrix display device adjusts brightness by applying a pulse width modulation (PWM) method itself or by using the PWM method utilizing a pulse amplitude modulation (PAM) method. In this instance, a capacitor is necessarily installed inside every pixel (or subpixel).

[0013] If the light-emitting circuit is designed so that a capacitor is installed inside every pixel, constraints such as area may occur or additional problems may occur due to the capacitor inside each pixel.

[0014] Meanwhile, the luminance of light-emitting elements such as LEDs is determined by the value of the light-emitting current. Due to differences in manufacturing characteristics or environmental differences, the value of the light-emitting current can differ or the efficiency of the light-emitting element can vary significantly. In this instance, there is the inconvenience of having to adjust the luminance of the display constantly from outside the light-emitting circuit, such as a controller or display driver, so that the luminance uniformity of the entire display screen must be matched. In addition, the value of the light-emitting current may need to be adjusted to match the luminance between display screens, but no solution has been proposed yet to solve this problem.[Disclosure][Technical Problem]

[0015] Another object of the embodiment is to provide a display device having a new structure.

[0016] Another object of the embodiment is to provide a display device providing a new driving method.

[0017] Another object of the embodiment is to provide a display device that does not have a capacitor in the light-emitting circuit.

[0018] Another object of the embodiment is to provide a display device that does not require a display driving circuit comprising a converter that converts digital data into analog data.

[0019] Another object of the embodiment is to provide a display device that can efficiently measure a reference current and / or a light-emitting current.

[0020] Another object of the embodiment is to provide a display device that can have a simple circuit structure by using one measurement line.

[0021] Another object of the embodiment is to provide a display device that can secure uniformity of light-emitting current between displays (or frames) or between blocks, i.e., luminance uniformity.

[0022] The technical problems of the embodiments are not limited to those described in this item and include those that can be understood through the description of the invention.[Technical Solution]

[0023] According to one aspect of the embodiment to achieve the above or other objects, a display device comprising a plurality of subpixels, comprising: a plurality of light-emitting elements provided in the 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 the plurality of subpixels and connected to the reference current generation circuit and the plurality of light-emitting elements, wherein the reference current generation circuit and the plurality of light-emitting circuits are commonly connected to a second power line, and wherein the reference current generation circuit and the plurality of light-emitting circuits are commonly connected to a measurement line.

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

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

[0026] The reference current generation circuit may comprise a third control switch connected to the first transistor to be on / off a reference current.

[0027] Each of the plurality of light-emitting circuits may comprise a third control switch connected between the light-emitting element and the first transistor; a fourth control switch connected between the third power line; and the first transistor and a fifth control switch connected to the first transistor to be on / off a light-emitting current.

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

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

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

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

[0032] In a reference current measurement mode when light-emitting, the first control switch of the reference current generation circuit may be turned off, the second control switch and the third control switch of the reference current generation circuit may be turned on, the first control switch, the third control switch and the fifth control switch of at least one or more light-emitting circuit among the plurality of light-emitting circuits may be turned on, and the second control switch and the fourth control switch of the at least one or more light-emitting circuit may be turned off.

[0033] In a reference current measurement mode when not light-emitting, the first control switch of the reference current generation circuit may be turned off, the second control switch and the third control switch the reference current generation circuit may be turned on, the first control switch, the fourth control switch and the fifth control switch of at least one or more light-emitting circuit among the plurality of light-emitting circuits may be turned on, and the second control switch and the third control switch of the at least one or more light-emitting circuit may be turned off.

[0034] In a light-emitting current measurement mode when light-emitting, the first control switch and the third control switch of the reference current generation circuit may be turned on, the second control switch of the reference current generation circuit may be turned off, the first control switch and the fourth control switch of at least one or more light-emitting circuit among the plurality of light-emitting circuits may be turned off, and the second control switch, the third control switch and the fifth control switch of the at least one or more light-emitting circuit may be turned on.

[0035] In a non-light-emitting current measurement mode when not light-emitting, the first control switch and the third control switch of the reference current generation circuit may be turned on, the second control switch of the reference current generation circuit may be turned off, the first control switch and the third control switch of at least one or more light-emitting circuit among the plurality of light-emitting circuits may be turned off, and the second control switch, the fourth control switch and the fifth control switch of the at least one or more light-emitting circuit may be turned on.

[0036] The display device may further comprise a current measurement circuit connected to the measurement line to measure at least one or more of a reference current or a light-emitting current; and a current control circuit configured to control at least one of the voltage generation circuit or the reference current generation circuit based on a measured current.[Advantageous Effects]

[0037] The effect of the display device according to the embodiment is described as follows.

[0038] According to at least one of the embodiments, there is an advantage in that the light-emitting circuit does not have a capacitor, so that it is not subject to area constraints, and thus the aperture ratio can be increased, thereby improving luminance.

[0039] According to at least one of the embodiments, there is an advantage that the circuit structure can be simplified, the area occupied can be reduced, and the cost can be reduced because a display driving device comprising a converter that converts digital data into analog data is not required.

[0040] According to at least one of the embodiments, there is an advantage that the light-emitting current for emitting the light-emitting element may be adjusted differently, so that accurate luminance adjustment is possible at any time.

[0041] According to at least one of the embodiments, there is an advantage that the reference current may be adjusted differently, so that accurate luminance adjustment is possible at any time.

[0042] According to at least one of the embodiments, there is an advantage that the reference voltage for adjusting the reference current may be adjusted differently, so that accurate luminance adjustment is possible at any time.

[0043] According to at least one of the embodiments, since the reference voltage and the reference current are adjusted simultaneously, the number of different light-emitting currents may increase, so that the luminance adjustment can be more precise, thereby implementing a high-quality image.

[0044] According to at least one of the embodiments, the reference voltage and / or the reference current may be adjusted between the displays (or frames), thereby ensuring luminance uniformity between the displays (or frames).

[0045] According to at least one of the embodiments, in a plurality of blocks (or modules) each comprising 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 of each module may be adjusted. Accordingly, luminance uniformity of the light-emitting current generated by the light-emitting circuit between the modules can be ensured.

[0046] According to at least one of the embodiments, the light-emitting current, and the non-light-emitting current, can be measured through a measurement line commonly connected to the reference current generation circuit and the light-emitting circuit, various currents, such as the reference current. By controlling (or compensating) the reference voltage and the reference current through the various currents measured in this way, more precise luminance uniformity can be secured.

[0047] Additional scope of applicability of the embodiments will become apparent from the detailed description that follows. However, since various changes and modifications within the idea and scope of the embodiments may be clearly understood by those skilled in the art, the detailed description and specific embodiments, such as preferred embodiments, should be understood as being given by way of example only.[Description of Drawings]

[0048] FIG. 1 is a circuit diagram illustrating an existing light-emitting circuit. FIG. 2 is a block diagram illustrating a display device according to a first embodiment. FIG. 3 is a block diagram illustrating a display device according to a second embodiment. FIG. 4 illustrates a display device according to the second embodiment operating in a light-emitting mode. FIG. 5 illustrates a display device according to the second embodiment operating in a reference current measurement mode. FIG. 6 illustrates a display device according to the second embodiment operating in a light-emitting current measurement mode. FIG. 7 illustrates a display device according to the second embodiment operating in a non-light-emitting current measurement mode. FIG. 8 is a block diagram illustrating a display device according to a third embodiment.

[56] FIG. 9 illustrates a display device according to the third embodiment that operates in a reference current measurement mode when light-emitting. FIG. 10 illustrates a display device according to the third embodiment that operates in a reference current measurement mode when not light-emitting. FIG. 11 illustrates a display device according to the third embodiment that operates in a light-emitting current measurement mode when light-emitting. FIG. 12 illustrates a display device according to the third embodiment that operates in a non-light-emitting current measurement mode when not light-emitting.

[0049] The sizes, shapes, dimensions, etc. of elements shown in the drawings can differ from actual ones. In addition, even if the same elements are shown in different sizes, shapes, dimensions, etc. between the drawings, this is only an example on the drawing, and the same elements have the same sizes, shapes, dimensions, etc. between the drawings.[Mode for Invention]

[0050] Hereinafter, the embodiment disclosed in this specification will be described in detail with reference to the accompanying drawings, but the same or similar elements are given the same reference numerals regardless of reference numerals, and redundant descriptions thereof will be omitted. The suffixes 'module' and 'unit' for the elements used in the following descriptions are given or used interchangeably in consideration of ease of writing the specification, and do not themselves have a meaning or role that is distinct from each other. In addition, the accompanying drawings are for easy understanding of the embodiment disclosed in this specification, and the technical idea disclosed in this specification is not limited by the accompanying drawings. Also, when an element such as a layer, region or substrate is referred to as being 'on' another element, this means that there can be directly on the other element or be other intermediate elements therebetween.

[0051] Hereinafter, "~module", "block", "~unit", etc. may be composed of "~circuit" or "integrated circuit". "~module", "block", "~ unit", etc. may be used interchangeably with "~circuit" or "integrated circuit".[First embodiment]

[0052] FIG. 2 is a block diagram illustrating a display device according to a first embodiment.

[0053] Referring to FIG. 2, the display device according to the first embodiment may comprise 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, etc.

[0054] The display device according to the first embodiment may comprise a display panel. The display panel may comprise a plurality of pixels. The display panel may comprise a plurality of subpixels SP-1 to SP-N. A plurality of subpixels SP-1 to SP-N may be included in one pixel.

[0055] The display panel may comprise a display region comprising a plurality of pixels and a non-display region excluding the display region. In addition, in the display panel, the emission region may be a region corresponding to each of the plurality of subpixels SP-1 to SP-N, and the non-emission region may be a region corresponding between the plurality of subpixels SP-1 to SP-N.

[0056] A voltage generation circuit 150, a reference current generation circuit 110, a plurality of light-emitting circuits 130-1 to 130-N, and a plurality of light-emitting elements 120-1 to 120-N may be provided in a display panel. The plurality of light-emitting elements 120-1 to 120-N may be provided in an emission region.

[0057] As an example, the voltage generation circuit 150, the reference current generation circuit 110, and the plurality of light-emitting circuits 130-1 to 130-N may each be individually implemented as an IC.

[0058] As another example, the voltage generation circuit 150 and the reference current generation circuit 110 may be implemented as an IC in which is unified into one. In this instance, the unified IC may be provided in an emission region or a non-emission region. The plurality of light-emitting circuits 130-1 to 130-N may be provided with the plurality of light-emitting elements 120-1 to 120-N in the plurality of subpixels SP-1 to SP-N, respectively. 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.

[0059] As another example, the voltage generation circuit 150, the reference current generation circuit 110, and the plurality of light-emitting circuits 130-1 to 130-N may be implemented as an IC in which is unified into one. In this instance, the unified IC is provided in a non-emission region, and the plurality of light-emitting elements 120-1 to 120-N may be provided in the plurality of subpixels SP-1 to SP-N.

[0060] The drawing illustrates a plurality of subpixels SP-1 to SP-N arranged in a row along the horizontal direction, but the plurality of subpixels SP-1 to SP-N may be arranged in a row along the vertical direction or in a matrix form.

[0061] The plurality of subpixels SP-1 to SP-N may be electrically connected to a first power line 141 141, a second power line 142, and a measurement line 145. A first power voltage EVDD may be supplied to the first power line 141, and a second power voltage EVSS may be supplied to the second power line 142. The first power voltage EVDD may be a high-potential voltage and may be higher than the second power voltage EVSS, which is a low-potential voltage. The second power voltage EVSS may be, for example, grounded or 0 V, but is not limited thereto. The light-emitting current of at least one or more light-emitting circuit among the plurality of light-emitting circuits 130-1 to 130-N of the plurality of subpixels SP-1 to SP-N may be measured through the measurement line 145.

[0062] The plurality of subpixels SP-1 to SP-N may comprise a plurality of red subpixels, a plurality of green subpixels, and a plurality of blue subpixels. A unit pixel may be configured by adjacent red subpixel, green subpixel, and blue subpixel. 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 are not limited thereto.

[0063] The first subpixel SP-1 may emit red light, the second subpixel SP-2 may emit green light, and the third subpixel SP-3 may emit blue light. In addition, the plurality of subpixels SP-1 to SP-N may further comprise a plurality of transparent subpixels that emit transparent light.

[0064] Each of the plurality of subpixels SP-1 to SP-N may comprise at least one or more light-emitting element 120-1 to 120-N. For example, a first subpixel may comprise at least one or more red light-emitting element for emitting red light. For example, a second subpixel may comprise at least one or more green light-emitting element for emitting green light. For example, a third subpixel may comprise at least one or more blue light-emitting element for emitting blue light. The plurality of light-emitting elements 120-1 to 120-N may comprise an organic semiconductor light-emitting element, an inorganic semiconductor light-emitting element, a micro LED (hereinafter, µ-LED), a nano LED, etc.

[0065] The plurality of light-emitting elements 120-1 to 120-N may be commonly connected to a first power line 141. The plurality of light-emitting elements 120-1 to 120-N may be connected to a plurality of light-emitting circuits 130-1 to 130-N, respectively.

[0066] The plurality of light-emitting circuits 130-1 to 130-N may drive the plurality of light-emitting elements 120-1 to 120-N of the plurality of subpixels SP-1 to SP-N to emit a plurality of color lights.

[0067] The plurality of light-emitting circuits 130-1 to 130-N may be commonly connected to a second power line 142. The plurality of light-emitting circuits 130-1 to 130-N may be commonly connected to a third power line 143. The plurality of light-emitting circuits 130-1 to 130-N may be commonly connected to the measurement line 145.

[0068] The plurality of light-emitting circuits 130-1 to 130N may generate light-emitting currents IEM1 to IEMN for supplying corresponding light-emitting elements 120-1 to 120-N between the first power line 141 and the second power line 142. The light-emitting currents IEM1 to IEMN may be referred to as driving currents, luminance currents, etc.

[0069] For example, in the first subpixel SP-1, the first light-emitting circuit 130-1 may be electrically connected to the first light-emitting element 120-1 to supply a first light-emitting current IEM1 to the first light-emitting element 120-1, so that the first light emitting element 120-1 may be driven to emit first color light. For example, in the second subpixel SP-2, the second light-emitting circuit 130-2 may be electrically connected to the second light-emitting element 120-2 to supply a second light-emitting current IEM2 to the second light-emitting element 120-2, so that the second light-emitting element 120-2 may be driven to emit second color light. In the third subpixel SP-3, the third light-emitting circuit 130-3 may be electrically connected to the third light-emitting element 120-3 to supply a third light-emitting current IEM3) to the third light-emitting element 120-3, so that the third light-emitting element 120-3 may be driven to emit third color light. 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 are not limited thereto.

[0070] Meanwhile, the plurality of light-emitting circuits 130-1 to 130N may individually or simultaneously output light-emitting currents IEM1 to IEMN through the measurement line 145. The output light-emitting currents IEM1 to IEMN may be measured by the current measurement circuit 170 to be described later.

[0071] Meanwhile, the reference current generation circuit 110 may generate the reference current IREF. The reference current generation circuit 110 may be commonly connected to the plurality of subpixels SP-1 to SP-N.

[0072] The reference current IREF may be used to generate the plurality of light-emitting currents IEM1 to IEMN flowing in the plurality of subpixels SP-1 to SP-N. That is, the reference current IREF generated by the reference current generation circuit 110 may be copied to the plurality of subpixels SP-1 to SP-N, so that the light-emitting currents IEM1 to IEMN may be generated in each of the subpixels SP-1 to SP-N. For example, in each subpixel SP-1 to SP-N, the light-emitting currents IEM1 to IEMN corresponding to the reference current IREF may be generated using the current mirror method. To this end, a current mirror circuit may be configured by at least one transistor of the reference current generation circuit 110 and at least one transistor of each of the plurality of light-emitting circuits 130-1 to 130-N. The at least one transistor of the reference current generation circuit 110 may be diode-connected. A gate of at least one transistor of the reference current generation circuit 110 and a gate of at least one transistor of each of the plurality of light-emitting circuits 130-1 to 130-N may be commonly connected to a node G.

[0073] The reference current IREF and the light-emitting currents IEM1 to IEMN may be constant currents. The constant current may mean that current consistently flows even when the voltage applied to both terminals changes.

[0074] The light-emitting currents IEM1 to IEMN may each be current corresponding to the reference current IREF. The light-emitting current IEM1 to IEMN may be equal to or greater than the reference current IREF. That is, the plurality of light-emitting circuits 130-1 to 130-N may generate light-emitting currents IEM1 to IEMN equal to or greater than the reference current IREF according to a preset ratio, that is, a copy ratio.

[0075] The copy ratio may be determined by designing the aspect ratio of each of the transistors of the plurality of light-emitting circuits 130-1 to 130-N differently with respect to the aspect ratio of the transistor of the reference current generation circuit 110.

[0076] For example, when the aspect ratios of the transistor of the light-emitting circuits 130-1 to 130-N is each equal to the aspect ratio of the transistor of the reference current generation circuit 110, the copy ratio is 1, and the light-emitting currents IEM1 to IEMN generated by the plurality of light-emitting circuits 130-1 to 130-N may be equal to the reference current IREF. For example, when the aspect ratio of the transistor of the light-emitting circuit 130-1 to 130-N is greater than the aspect ratio of the transistor of the reference current generation circuit 110, the copy ratio has a value greater than 1, so that the light-emitting current IEM1 to IEMN generated from the light-emitting circuit 130-1 to 130-N may be greater than the reference current IREF.

[0077] Therefore, since the aspect ratio of each of the transistors of the plurality of light-emitting circuits 130-1 to 130-N is freely designed, the light-emitting currents IEM1 to IEMN required in the corresponding subpixels SP-1 to SP-N can be accurately and easily obtained.

[0078] According to an embodiment, by using the copy ratio, the aspect ratio of the transistor of the reference current generation circuit 110 may be designed to be smaller than the aspect ratio of the transistors of the light-emitting circuits 130-1 to 130-N, so that the reference current generation circuit 110 may generate a relatively small reference current IREF. Accordingly, the burden of generating a large reference current IREF can be reduced, the size of the reference current generation circuit 110 can be reduced, and power consumption can be reduced. In addition, since the plurality of light-emitting currents IEM1 to IEMN of the plurality of light-emitting circuits 130-1 to 130-N have large values, the contrast ratio can be improved and high luminance can be implemented.

[0079] Meanwhile, the reference current generation circuit 110 may be electrically connected to the third power line 143, the second power line 142, and the measurement line 145.

[0080] The third power line 143 may be commonly connected to the reference current generation circuit 110 and the plurality of light-emitting circuits 130-1 to 130-N. The second power line 142 may be commonly connected to the reference current generation circuit 110 and the plurality of light-emitting circuits 130-1 to 130-N.

[0081] The measurement line 145 may be commonly connected to the reference current generation circuit 110 and the plurality of light-emitting circuits 130-1 to 130-N.

[0082] Accordingly, the reference current IREF generated from the reference current generation circuit 110 may be measured through the measurement line 145, or the plurality of light-emitting currents IEM1 to IEMN generated from the plurality of light-emitting circuits 130-1 to 130-N may be individually or simultaneously measured through the measurement line 145. When the light-emitting circuits 130-1 to 130-N are selected to be connected between the first power line 141 and the second power line 142, the light-emitting currents IEM1 to IEMN may be generated from the light-emitting circuits 130-1 to 130-N.

[0083] In addition, the non-light-emitting currents generated from the plurality of light-emitting circuits 130-1 to 130-N may be measured through the measurement line 145. When the light-emitting circuits 130-1 to 130-N are selected to be connected between the third power line 143 and the second power line 142, non-light-emitting current may be generated in the light-emitting circuits 130-1 to 130-N.

[0084] The third power voltage PVDD may be supplied to the third power line 143. The third power voltage PVDD may be a high-potential voltage and may be similar to the first power voltage EVDD. For example, the third power voltage PVDD may be lower than the first power voltage EVDD, but is not limited thereto.

[0085] Since the second power line 142 is commonly connected to the reference current generation circuit 110 and the plurality of light-emitting circuits 130-1 to 130-N, the transistor of the reference current generation circuit 110 and the plurality of transistors of the plurality of light-emitting circuits 130-1 to 130-N constituting the current mirror circuit may commonly use the second power voltage EVSS supplied to the second power line 142. Accordingly, since the transistor of the reference current generation circuit 110 and the plurality of transistors of the plurality of light-emitting circuits 130-1 to 130-N are simultaneously affected by the IR drop related to the second power voltage EVSS, they are not affected by the change in the light-emitting current IEM1 to IEMN of each of the plurality of subpixels SP-1 to SP-N, so that poor image quality can be prevented.

[0086] Meanwhile, the plurality of light-emitting circuits 130-1 to 130-N may adjust the on-section (or emission section) of the light-emitting elements 120-1 to 120-N by period (or frame) using digital data and program signals, respectively, so that it may be possible to express grayscale in images. Depending on the digital data, it may be determined whether the light-emitting currents IEM1 to IEMN generated in the light-emitting circuits 130-1 to 130-N are supplied to the light-emitting elements 120-1 to 120-N. For example, the digital data may comprise a signal regarding light-emitting / non-light-emitting of the light-emitting elements 120-1 to 120-N. For example, when the digital data is "1", the light-emitting currents IEM1 to IEMN generated in the light-emitting circuits 130-1 to 130-N may be supplied to the light-emitting elements 120-1 to 120-N, respectively, so that the light-emitting elements 120-1 to 120-N may emit light. For example, when digital data is "0", the light-emitting currents IEM1 to IEMN generated in the light-emitting circuits 130-1 to 130-N are not supplied to the light-emitting elements 120-1 to 120-N, respectively, so that the light-emitting elements 120-1 to 120-N do not emit light.

[0087] The program signal is a control signal for writing input data, and may comprise grayscale information, etc. According to the grayscale information included in the program signal, the width of the on-section (or the emission section) may be determined differently, so that an image having different grayscale or luminance can be displayed. For example, the larger the on-section, the higher the gray level image can be displayed. For example, since the corresponding light-emitting elements 120-1 to 120-N emit light in different on-sections for each frame for the same subpixel, an image having different grayscales for each frame may be displayed.

[0088] Therefore, whether or not the light-emitting elements 120-1 to 120-N emit light may be determined according to digital data, and an image having a desired grayscale or luminance may be displayed by adjusting the on-section (emission section) of the light-emitting elements 120-1 to 120-N according to the program signal.

[0089] In the drawing, the node G may be a node between the gate of the transistor of the reference current generation circuit 110 and the gate of each of the transistors of the plurality of light-emitting circuits 130-1 to 130-N constituting the current mirror circuit.

[0090] A predetermined voltage may be generated at the node G through the transistor of the reference current generation circuit 110 by the reference current IREF generated by the reference current generation circuit 110. A plurality of light-emitting currents IEM1 to IEMN may be generated in the transistors of the plurality of light-emitting elements 120-1 to 120-N by using the predetermined voltage. In this instance, as described above, the aspect ratios of the transistors of the light-emitting elements 120-1 to 120-N may be designed to be the same as or different from the aspect ratio of the transistor of the reference current generation circuit 110, so that the same or different light-emitting currents IEM1 to IEMN may be generated in the transistors of the plurality of light-emitting elements 120-1 to 120-N based on the voltage on the node G.

[0091] Meanwhile, in the embodiment, a plurality of subpixels SP-1 to SP-N may be driven simultaneously. That is, a plurality of subpixels SP-1 to SP-N may be driven simultaneously within one frame, and the on-sections of the light-emitting elements 120-1 to 120-N of the plurality of subpixels SP-1 to SP-N are adjusted, respectively, so that images with different grayscales may be displayed on the subpixels SP-1 to SP-N, respectively.

[0092] Meanwhile, as described above, the reference current generation circuit 110 and the plurality of light-emitting circuits 130-1 to 130-N may be commonly connected to the second power line 142 and also commonly connected to the measurement line 145.

[0093] As a first example, the reference current generation circuit 110 connected to the third power line 143 and the second power line 142 may generate the reference current IREF.

[0094] As a second example, a plurality of light-emitting circuits 130-1 to 130-N connected to the first power line 141 and the second power line 142 may generate a plurality of light-emitting currents IEM1 to IEMN.

[0095] As a third example, a reference current IREF generated by a reference current generation circuit 110 may be output through a measurement line 145.

[0096] As a fourth example, a plurality of light-emitting currents IEM1 to IEMN generated by a plurality of light-emitting circuits 130-1 to 130-N may be output individually or simultaneously through a measurement line 145.

[0097] As a fifth example, a non-light-emitting current generated by a plurality of light-emitting circuits 130-1 to 130-N may be output through a measurement line 145.

[0098] Meanwhile, in the embodiment, the reference current IREF, the light-emitting currents IEM1 to IEMN, and / or the non-light-emitting current output through the measurement line 145 may be measured and used to control the reference current generation circuit 110 and / or the plurality of light-emitting circuits 130-1 to 130-N.

[0099] To this end, the display device according to the first embodiment may comprise a current measurement circuit 170, a current control circuit 180, etc.

[0100] The current measurement circuit 170 may be electrically connected to the reference current generation circuit 110 and the plurality of light-emitting circuits 130-1 to 130-N through the measurement circuit 145. The current measurement circuit 170 may measure the reference current IREF, the light-emitting currents IEM1 to IEMN, and / or the non-light-emitting current through the measurement circuit 145, and obtain measurement results (I M1 to I M4 of the mathematical formulas 3 to 6).

[0101] The current control circuit 180 may generate control signals (such as E11, C21, etc. of FIG. 3) for controlling the reference current generation circuit 110 and / or the plurality of light-emitting circuits 130-1 to 130-N based on the reference current IREF, the light-emitting currents IEM1 to IEMN, and / or the non-light-emitting current measured by the current measurement circuit 170. As will be described later, the plurality of selection switches 156-1 of the voltage generation circuit 150 (such as 150 of FIG. 3) may be selectively turned on in response to one control signal E11 of these control signals (such as E11, C21, etc.), so that the reference voltage VREF may be adjusted. In addition, the plurality of selection switches 112-1 of the reference current generation circuit 110 may be selectively turned on in response to another control signal C21) of the control signals (such as E11, C21, etc.), so that the reference current IREF may be adjusted.

[0102] For example, when the voltage generation circuit 150, the current generation circuit 110 and the plurality of light-emitting circuits 130-1 to 130-N are configured as one driving IC (first IC), the current measurement circuit 170 and the current control circuit 180 may be configured as a separate IC (second IC) from the first IC. Alternatively, the first IC and the second IC may be implemented as one.

[0103] The current measurement circuit 170 may measure the reference current IREF, the light-emitting currents IEM1 to IEMN and / or the non-light-emitting current. For example, the current measurement circuit 170 may measure the reference current IREF, the light-emitting currents IEM1 to IEMN and / or the non-light-emitting current through the current measurement circuit 170 during the production process of each first IC or during the display operation of the display device according to the first embodiment.

[0104] The current control circuit 180 may obtain the difference in the reference current IREF or the light-emitting current due to the difference in the characteristics of the plurality of first ICs that may occur during the production of the plurality of first ICs, and / or the measured non-light-emitting current, or the difference in the reference current IREF or the light-emitting current that may occur under the driving environment or specific conditions based on the measured reference current IREF, the measured light-emitting currents IEM1 to IEMN.

[0105] In addition, the current control circuit 180 may control the voltage generation circuit 150 to adjust the reference voltage VREF or control the reference current generation circuit 110 to adjust the reference current IREF based on the control signals (E11, C21, etc.) comprising compensation information according to the difference. Accordingly, the uniformity of the current between the plurality of first ICs, for example, the reference current IREF or the light-emitting current, may be secured, so that the image quality can be improved.[Second embodiment]

[0106] FIG. 3 is a block diagram illustrating a display device according to a second embodiment. FIG. 3 illustrates the circuit configuration of each 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 illustrated in FIG. 2. The current measurement circuit 170 and the current control circuit 180 illustrated in FIG. 2 may also be included in FIG. 3. FIG. 3 illustrates only the circuit configuration of the first light-emitting circuit 130-1 of the first subpixel SP-1 in FIG. 2. The circuit configurations of the second light-emitting circuit 130-2 to the Nth light-emitting circuit 130-N may be identical to the circuit configuration of the first light-emitting circuit 130-1. Therefore, the description of the circuit configurations of the second light-emitting circuit 130-2 to the Nth light-emitting circuit 130-N may be applied as is to the description of the circuit configuration of the first light-emitting circuit 130-1.

[0107] As illustrated in FIG. 3, the voltage generation circuit 150 may provide a reference voltage VREF to the reference current generation circuit 110. The voltage generation circuit 150 may be connected to the reference current generation circuit 110 through a node X. Therefore, the voltage generation circuit 150 may output the reference voltage VREF to the reference current generation circuit 110 through the node X. The reference current generation circuit 110 may generate a reference current IREF based on the reference voltage VREF.

[0108] The voltage generation circuit 150 may comprise a first transistor T31, a reference voltage adjustment circuit, control switches 151-1 and 151-2, etc.

[0109] The first transistor T31 may be diode-connected. That is, a gate and a drain of the first transistor may be electrically connected. The first transistor T31 may comprise a PMOS transistor, but is not limited thereto.

[0110] The reference voltage adjustment circuit may be connected to the first transistor T31 to adjust the reference voltage VREF. The reference voltage adjustment circuit may comprise a second transistor T32-1 and a selection switch 156-1. The second transistor T32-1 may be diode-connected and may comprise a PMOS transistor.

[0111] Although the drawing illustrates one second transistor T32-1 and one selection switch 156-1, a plurality of second transistors may be connected in parallel with each other, and a plurality of selection switches may be connected in series with the plurality of second transistors. Hereinafter, T32-1 may be used as a drawing symbol indicating a plurality of second transistors, and 156-1 may be used as a drawing symbol indicating a plurality of selection switches.

[0112] The gates of the plurality of second transistors T32-1 may be connected in common. In this instance, the plurality of second transistors T32-1 may be turned on / off in response to the control signal E11. By selectively turning on a plurality of second transistors T32-1, at least one or more second transistor among the plurality of second transistors T32-1 may be selected. The reference voltage VREF may be adjusted using the selected at least one or more transistor T32-1 and the first transistor T31.

[0113] A plurality of second transistors T32-1 of the reference voltage adjustment circuit and a plurality of second transistors T22-1 of the reference current adjustment circuit 115 may form a current mirror circuit, respectively.

[0114] Although one second transistor T22-1 and one selection switch 112-1 are illustrated in the drawing, the plurality of second transistors may be connected in parallel with each other, and the plurality of selection switches may be connected in series to the plurality of second transistors, respectively. Hereinafter, T22-1 may be used as a drawing symbol indicating the plurality of second transistors, and 112-1 may be used as a drawing symbol indicating the plurality of selection switches.

[0115] The gates of the plurality of second transistors T32-1 of the reference voltage control circuit and the gates of the plurality of second transistors T22-1 of the reference current adjustment circuit 115 may be commonly connected to the node X.

[0116] In this instance, the reference voltage VREF adjusted by at least one or more second transistor selected from among the plurality of second transistors T32-1 and the first transistor T31 may be output to the node X. At least one or more constant current may be generated from at least one or more second transistor T22-1 selected from among the plurality of second transistors T22-1. When the reference voltage VREF is adjusted differently, at least one or more constant current may also be changed differently.

[0117] Meanwhile, the plurality of selection switches 156-1 may be connected in series with the plurality of second transistors T32-1, respectively. The plurality of selection switches 156-1 may each comprise a third transistor T33-1. The third transistor T33-1 may comprise a PMOS transistor, but is not limited thereto. For example, the plurality of third transistors T33-1 may be connected in series with the plurality of second transistors T32-1, respectively, between the third power supply line 143 and the plurality of second transistors T32-1.

[0118] Meanwhile, the first transistor T31 may have a predetermined diode voltage. The plurality of second transistors T32-1 may have the same diode voltage. The plurality of second transistors T32-1 may have different diode voltages. The diode voltage may be a threshold voltage of the second transistor T32-1, but is not limited thereto.

[0119] The plurality of third transistors T33-1 may be each connected in series with the plurality of second transistors T32-1, so that at least one or more second transistor selected from among the plurality of second transistors T32-1 and a reference voltage VREF determined by the first transistor T31 may be output through the node X in response to selective turning on of the plurality of third transistors T33-1. The diode voltage of the first transistor T31 and the diode voltage of the selected at least one or more second transistor T32-1 may be voltage-divided to generate the reference voltage VREF, but is not limited thereto.

[0120] Meanwhile, the control switches 151-1 and 151-2 may control on / off of the display operation. The control switches 151-1 and 151-2 may control the operation of the voltage generation circuit 150, the operation of the reference current generation circuit 110, and the operation of each of the light-emitting circuits 130-1 to 130-N.

[0121] The control switches 151-1 and 151-2 may comprise a first control transistor T41 and a second control transistor T42.

[0122] The first control transistor T41 may be connected between the first transistor T31 and the fourth power line 144, and the second control transistor T42 may be connected between the third power line 143 and the first transistor T31. The third power voltage PVDD may be supplied to the third power line 143, and the fourth power voltage PVSS may be supplied to the fourth power line 144. The third power voltage PVDD may be greater than the fourth power voltage PVSS. The second power voltage and the fourth power voltage PVSS may be grounded, i.e., 0 V, but are not limited thereto. The third power voltage PVDD may be less than the first power voltage.

[0123] The first control transistor T41 may comprise an NMOS transistor, and the second control transistor T42 may comprise a PMOS transistor. A gate of the first control transistor T41 and a gate of the second control transistor T42 may be commonly connected.

[0124] For example, the first control transistor T41 may be turned on and the second control transistor T42 may be turned off in response to a control signal EC of a high level, so that a display operation can be performed. In this instance, the reference voltage VREF may be output from the voltage generation circuit 150 to the node X, the reference current generation circuit 110 may generate the reference current IREF based on the reference voltage VREF, and the first light-emitting circuit 130-1 may generate the first light-emitting current IEM1 based on the reference current IREF. Accordingly, the first light-emitting element 120-1 may be emitted by the first light-emitting current IEM1, so that an image may be displayed.

[0125] For example, the first control transistor T41 may be turned off and the second control transistor T42 may be turned on in response to a control signal EC of a low level, so that the display operation may be stopped. In this instance, since the voltage generation circuit 150 is not operated, the reference voltage VREF may be not output to the node X. Accordingly, 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 may be not generated, so that an image may be not displayed.

[0126] Meanwhile, the reference current generation circuit 110 may be connected to the first subpixel SP-1. The reference current IREF generated or adjusted in the reference current generation circuit 110 may be copied to the first subpixel SP-1, so that the first light-emitting current IEM1 may be generated in the first subpixel SP-1, and the first light-emitting element 120-1 may emit light by the first light-emitting current IEM1.

[0127] In the embodiment, the reference current generation circuit 110 may comprise a reference current adjustment circuit 115 that adjusts the reference current IREF. When the reference current IREF is adjusted in the reference current adjustment circuit 115, the first light-emitting circuit 130-1 may generate (or adjust) the first light-emitting current IEM1 using the adjusted reference current IREF. For example, when the reference current IREF is adjusted to increase, the first light-emitting current IEM1 may increase in response to the adjusted reference current IREF. For example, when the reference current IREF is adjusted to decrease, the first light-emitting current IEM1 may decrease in response to the adjusted reference current IREF.

[0128] The luminance of the first light-emitting element 120-1 may be determined according to the first light-emitting current IEM1. That is, as the first light-emitting current IEM1 increases, the luminance of the first light-emitting element 120-1 may increase. For example, the first light-emitting current IEM1 may decrease due to differences in manufacturing characteristics or environmental differences, so that the luminance of the first light-emitting element 120-1 may be reduced. In this instance, the reference current IREF may be adjusted to increase in the reference current adjustment circuit 115, so that the first light-emitting current IEM1 of the first light-emitting circuit 130-1 may increases, thereby increasing the luminance of the first light-emitting element 120-1.

[0129] The reference current adjustment circuit 115 may comprise a constant current source 111-1 and a selection switch 112-1. Although the drawing shows one constant current source 111-1 and one selection switch 112-1, a plurality of constant current sources may be connected in parallel with each other, and a plurality of selection switches may be connected in series with each other to the plurality of constant current sources. Hereinafter, 111-1 may be used as a drawing symbol indicating the plurality of constant current sources, and 112-1 may be used as a drawing symbol indicating the plurality of selection switches.

[0130] The plurality of constant current sources 111-1 may each be a source that generates a constant current. The plurality of constant current sources 111-1 may be connected in parallel with each other between the third power supply line 143 and the first transistor T21.

[0131] The plurality of constant current sources 111-1 and the plurality of selection switches 112-1 may each be electrically connected. The plurality of constant current sources 111-1 may be selected according to the switching of the plurality of selection switches 112-1. The plurality of constant current sources 111-1 may each comprise a second transistor T22-1, and the plurality of selection switches 112-1 may each comprise a third transistor T23-1. The second transistor T22-1 and the third transistor T23-1 may be PMOS transistors, but are not limited thereto.

[0132] For example, the plurality of second transistors T22-1 may be connected in parallel between the third power supply line 143 and the first transistor T21.

[0133] In this instance, the gates of the plurality of second transistors T22-1 may be commonly connected. The plurality of second transistors T22-1 may generate a plurality of constant currents based on a reference voltage VREF input to the gates thereof. The plurality of constant currents may be the same or different.

[0134] At this time, the generation of the plurality of constant currents may be determined depending on whether the plurality of selection switches 112-1 are turned on / off.

[0135] The plurality of selection switches 112-1 may be connected in series with the plurality of second transistors T22-1, respectively. The plurality of selection switches 112-1 may comprise the third transistor T23-1, respectively. The third transistor T23-1 may comprise a PMOS transistor, but is not limited thereto.

[0136] For example, the plurality of third transistors T23-1 may be connected in series with the plurality of second transistors T22-1, respectively, between the third power line 143 and the first transistor T21. In this instance, a plurality of constant currents may be generated in the plurality of second transistors T22-1 in response to the turning on of the plurality of third transistors T23-1.

[0137] A reference current IREF may be generated using at least one or more constant current selected from among the plurality of constant currents. For example, as the number of selected constant currents increases, the reference current IREF may increase. The reference current IREF may be used to generate the first light-emitting current IEM1 in the first light-emitting circuit 130-1.

[0138] The plurality of third transistors T23-1 may be turned on / off according to the plurality of selection signals C21. Since the plurality of third transistors T23-1 are PMOS transistors, when the plurality of selection signals C21 are at a low level, each of the plurality of third transistors T23-1 may be turned on, and when the plurality of selection signals C21 are at a high level, each of the plurality of third transistors T23-1 may be turned off.

[0139] Although the drawing shows four constant current sources 111-1 and four selection switches 112-1, more constant current sources and selection switches may be provided.

[0140] Meanwhile, the reference current generation circuit 110 may comprise a first transistor T21 and third control switches 113-1 and 113-2 connected to the first transistor T21.

[0141] The first transistor T21 may be diode-connected. That is, a gate and a drain of the first transistor T21 may be commonly connected. The reference current IREF determined by the plurality of constant currents generated from the plurality of constant current sources 111-1 may flow through the first transistor T21.

[0142] The first transistor T21 of the reference current generation circuit 110 may form a current mirror circuit with a first transistor T11 of the first light-emitting circuit 130-1. In this instance, 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 node G.

[0143] The third control switches 113-1 and 113-2 may be connected to the first transistor T21 to control the on / off of the reference current IREF. The "on" of the reference current IREF may mean that the reference current IREF flows to the first transistor T21, and the "off" of the reference current IREF may mean that the reference current IREF does not flow to the first transistor T21.

[0144] The third control switch may comprise a third-first control switch 113-1 and a third-second control switch 113-2. The third-first control switch 113-1 may be connected between the first transistor T21 and the second power line 142, and the third-second control switch 113-2 may be connected between the reference current adjustment circuit 115 and the first transistor T21.

[0145] The third-first control switch 113-1 may comprise a sixth transistor T24, and the third-second control switch 113-2 may comprise a seventh transistor T25. The sixth transistor T24 may comprise an NMOS transistor, and the seventh transistor T25 may comprise a PMOS transistor.

[0146] The third-first control switch 113-1 and the third-second control switch 113-2 may be turned on or off simultaneously in response to the control signals D1 and D2. For example, when the control signal D1 has a high level and the control signal D2 has a low level, the third-first control switch 113-1 and the third-second control switch 113-2 may both be turned on. For example, when the control signal D1 has a low level and the control signal D2 has a high level, the third-first control switch 113-1 and the third-second control switch 113-2 may both be turned off.

[0147] When the third-first control switch 113-1 and the third-second control switch 113-2 are in an open state in response to the control signals D1 and D2, the reference current IREF does not flow to the first transistor T21, which may mean that the reference current IREF is "off". When the third-first control switch 113-1 and the third-second control switch 113-2 are in a closed state in response to the control signals D1 and D2, the reference current IREF flows to the first transistor T21, which may mean that the reference current IREF is "on". A time period during which the reference current IREF flows to the first transistor T21 may be defined as an on-section. A time period during which the reference current IREF does not flow to the first transistor T21 may be defined as an off-section.

[0148] For example, it may be divided into an on-section and an off-section for each period. A period may be, for example, one frame, but is not limited thereto. During the on-section, the third-first control switch 113-1 and the third-second control switch 113-2 may be in a closed state, so that the reference current IREF may flow to the first transistor T21. During the off-section, the third-first control switch 113-1 and the third-second control switch 113-2 may be in an open state, so that the reference current IREF may not flow to the first transistor T21.

[0149] Meanwhile, the reference current generation circuit 110 may comprise the first control switch 116, the second control switch 117, and the third control switches 113-1 and 113-2.

[0150] The first control switch 116 may be connected between the first transistor T21 and the second power line 142, and the second control switch 117 may be connected between the first transistor T21 and the measurement line 145.

[0151] The first control switch 116 may comprise a fourth transistor T26, and the second control switch 117 may comprise a fifth transistor T27. The fourth transistor T26 and the fifth transistor T27 may comprise NMOS transistors, but are not limited thereto.

[0152] As an example, the first control switch 116 may be turned on and the second control switch 117 may be turned off. In this instance, the first transistor T21 may be connected to the second power line 142, and when the third control switches 113-1 and 113-2 are turned on, a reference current IREF determined based on at least one or more constant current generated by the reference current adjustment circuit 115 may be generated.

[0153] As another example, the first control switch 116 may be turned off and the second control switch 117 may be turned on. In this instance, the first transistor T21 may be connected to the measurement line 145, and when the third control switches 113-1 and 113-2 are turned on, the generated reference current IREF may be output through the measurement line 145.

[0154] Meanwhile, the first subpixel SP-1 may comprise 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.

[0155] The first light-emitting circuit 130-1 may drive the first light-emitting element 120-1 to emit light. To this end, the first light-emitting circuit 130-1 may generate a first light-emitting current IEM1, and the first light-emitting element 120-1 may emit light by the generated first light-emitting current IEM1. The first light-emitting current IEM1 may be a constant current.

[0156] The first light-emitting current IEM1 may be generated in response to a reference current IREF adjusted by the reference current generation circuit 110. That is, when the reference current IREF increases, the first light-emitting current IEM1 may also increase.

[0157] The first light-emitting circuit 130-1 may comprise a first transistor T11, fifth control switches SW11, SW12-1, and SW12-2, etc.

[0158] The first transistor T11 of the first light-emitting circuit 130-1 may be 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 line 141 and the second power line 142. For example, an anode electrode of the first light-emitting element 120-1 may be electrically connected to the first power line 141, a cathode electrode of the first light-emitting element 120-1 may be electrically connected to a drain of the first transistor T11, and a source of the first transistor T11 may be electrically connected to the second power line 142.

[0159] The first transistor T11 may generate the first light-emitting current IEM1. The first light-emitting current IEM1 may be generated based on the reference current IREF generated by the reference current generation circuit 110. The first transistor T11 may generate the first light-emitting current IEM1 corresponding to the reference current IREF generated by the reference current generation circuit 110. The first transistor T11 may generate a first light-emitting current IEM1, which 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 may emit light by the first light-emitting current IEM1.

[0160] A current mirror circuit may be configured 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, the first light-emitting current IEM1 may be generated in the first transistor T11 of the first light-emitting circuit 130-1 in response to the reference current IREF flowing in the first transistor T21 of the reference current generation circuit 110. At this time, the first light-emitting current IEM1 may be equal to or greater than the reference current IREF.

[0161] 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 thereto. 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 thereto.

[0162] The first transistor T21 of the reference current generation circuit 110 may be diode-connected, and a gate of the first transistor T21 of the reference current generation circuit 110 and a gate of the first transistor T11 of the first light-emitting circuit 130-1 may be commonly connected to the node G. In addition, a source of the first transistor T21 of the reference current generation circuit 110 and a source of the first transistor T11 of the first light-emitting circuit 130-1 may be commonly connected to the second power line 142.

[0163] In this instance, the reference current IREF flowing in the reference current generation circuit 110 may be represented by mathematical formula 1, and the first light-emitting current IEM1 flowing in the first light-emitting circuit 130-1 may be represented by mathematical formula 2. IREF = μ ⋅ C ox ⋅ W D L D ⋅ V G − EVSS − V TH 2 2 IEM = μ ⋅ C ox ⋅ W E L E ⋅ V G − EVSS − V TH 2 2

[0164] From mathematical formula 1, the voltage V G of the node G may be calculated. That is, the first transistor T21 of the reference current generation circuit 110 may be a conversion element that converts the reference current IREF into a voltage of the node G.

[0165] The first transistor T11 of the first light-emitting circuit 130-1 may be a conversion element that converts a voltage of the node G into the first light-emitting current IEM1.

[0166] From mathematical formulas 1 and 2, when the process constant (µ and Cox) and the aspect ratio (W D / L D and W E / L E ) of the first transistor T21 of the reference current generation circuit 110 and the first transistor T11 of the first light-emitting circuit 130-1 are the same, the reference current IREF and the first light-emitting current IEM1 may be the same. In this instance, the reference current IREF may be copied as it is and generated as the first light-emitting current IEM1 in the first light-emitting circuit 130-1.

[0167] In contrast, when the process constants (µ and Cox) are the same 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 but the aspect ratios (W D / L D and W E / L E ) are different, the reference current IREF and the first light-emitting current IEM1 may be different. For example, when the aspect ratio (W E / L E ) of the first transistor T11 of the first light-emitting circuit 130-1 is greater than the aspect ratio (W D / L D ) of the first transistor T21 of the reference current generation circuit 110, the first light-emitting current IEM1 may be greater than the reference current IREF. For convenience, the aspect ratio (W D / L D ) of the first transistor T21 of the reference current generation circuit 110 may be named as a first aspect ratio, and the aspect ratio (W E / L E ) of the first transistor T11 of the first light-emitting circuit 130-1 may be named as a second aspect ratio.

[0168] Therefore, the first aspect ratio (W D / L D ) may be designed to be small, so that a small reference current IREF may be generated in the reference current generation circuit 110. Accordingly, the burden of generating the reference current IREF can be reduced, the size of the reference current generation circuit 110 can be reduced, and power consumption can be reduced.

[0169] In addition, the second aspect ratio (W E / L E ) may be designed to be large, so that a large first light-emitting current IEM1 may be generated in the first light-emitting circuit 130-1. Accordingly, since the first light-emitting element 120-1 emits light through the large first light-emitting current IEM1, the contrast ratio can be improved and high luminance can be implemented.

[0170] Meanwhile, the fifth control switches SW11, SW12-1 and SW12-2 of the first light-emitting circuit 130-1 may be connected to the first transistor T11 to control the on / off of the first light-emitting current IEM1. The fifth control switches SW11, SW12-1 and SW12-2 may comprise 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 comprise an NMOS transistor, and the fifth-second control switch SW12-1 and the fifth-third control switch SW12-2 may comprise PMOS transistors, but are not limited thereto.

[0171] The fifth-first control switch SW11 may be connected between the first transistor T11 and the second power line 142, the fifth-second control switch SW12-1 may be connected between the first light-emitting element 120-1 and the first transistor T11, and the fifth-third control switch SW12-2 may be connected between the first transistor T11 and the third power line 143. A gate of the fifth-second control switch SW12-1 and a gate of the fifth-third control switch SW12-2 may be commonly connected.

[0172] The fifth-first control switch SW11 may comprise a sixth transistor T12-1, the fifth-second control switch SW12-1 may comprise a seventh transistor T13-1, and the fifth-third control switch SW12-2 may comprise an eighth transistor T13-2.

[0173] The sixth transistor T12-1 may comprise an NMOS transistor, and the seventh transistor T13-1 and the eighth transistor T13-2 may be PMOS transistors.

[0174] The fifth-first control switch SW11, the fifth-second control switch SW12-1, and the fifth-third control switch SW12-2 may be turned on or off simultaneously in response to the control signals C11 and C12. The fifth-second control switch SW12-1 and the fifth-third control switch SW12-2 may be turned on / off simultaneously by the control signal C12.

[0175] When the fifth-first control switch SW11 and the fifth-second control switch SW12-1 are in an open state in response to the control signals C11 and C12, the first light-emitting current IEM1 does not flow to the first transistor T11, which may mean that the first light-emitting current IEM1 may be "off". When the fifth-first control switch SW11 and the fifth-second control switch SW12-1 are in a closed state in response to the control signals C11 and C12, the first light-emitting current IEM1 may flow to the first transistor T11, which may mean that the first light-emitting current IEM1 may be "on". A time period during which the first light-emitting current IEM1 flows to the first transistor T11 may be defined as an on-section. A time period during which the first light-emitting current IEM1 does not flow to the first transistor T11 may be defined as an off-section.

[0176] For example, it may be divided into an on-section (or emission section) and an off-section (non-emission section) for each period. A period may be, for example, one frame, but is not limited thereto. During the on-section, the fifth-first control switch SW11 and the fifth-second control switch SW12-1 may be in a closed state, so that the first light-emitting current IEM1 may flow to the first transistor T11, and thus the first light-emitting element 120-1 may emit light. During the off-section, the fifth-first control switch SW11 and the fifth-second control switch SW12-1 may be in an open state, so that the first light-emitting current IEM1 may noy flow to the first transistor T11, and thus the first light-emitting element 120-1 may not emit light.

[0177] For convenience of explanation, the on-section in which the reference current IREF flows to the first transistor T21 of the reference current generation circuit 110 may be named as a first on-section, and the on-section in which the first light-emitting current IEM1 flows to the first transistor T11 of the first light-emitting circuit 130-1 may be named as a second on-section.

[0178] When the third control switches 113-1 and 113-2 of the reference current generation circuit 110 are in a closed state in response to the control signals D1 and D2, the reference current IREF may flow to the first transistor T21 of the reference current generation circuit 110 during the first on-section. When the fifth control switches SW11, SW12-1, and SW12-2 of the first light-emitting circuit 130-1 are in a closed state in response to the control signals C11 and C12, the first light-emitting current IEM1 may flow to the first transistor T11 of the first light-emitting circuit 130-1 during the second on-section.

[0179] The second on-section may be included in 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.

[0180] Meanwhile, the first light-emitting circuit 130-1 may comprise digital storage. The digital storage may 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.

[0181] The fifth control switches SW11, SW12-1 and SW12-2 may be turned on / off in response to the control signals C11 and C12. In response to the control signals C11 and C12, when the fifth control switches SW11, SW12-1 and SW12-2 are in a closed state during the second on-section, the first light-emitting current IEM1 may be generated in the first transistor T11, and the first light-emitting element 120-1 may emit light by the generated first light-emitting current IEM1.

[0182] Since the fifth control switches SW11, SW12-1, and SW12-2 are kept closed during the second on-section, the first light-emitting element 120-1 may be emitted during the second on-section.

[0183] The second on-section may be determined by a program signal, but is not limited thereto. The program signal may comprise grayscale information for determining the second on-section. Accordingly, the control signals C11 and C12 having a second on-section may be generated based on digital data and the program signal. For example, the larger the grayscale, the larger the second on-section may be. Accordingly, by changing the width of the second on-section, an image having a desired grayscale may be displayed.

[0184] Meanwhile, 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-section may be provided from an external source, such as a host, a data processing device, a processor, a controller, etc.

[0185] According to an embodiment, a first light-emitting current IEM1, which is a constant current, may be generated from the first transistor T11 of the first light-emitting circuit 130-1 in response to the reference current IREF generated from the reference current generation circuit 110. At this time, a second on-section may be determined or adjusted based on digital data and a program signal, and the first light-emitting element 120-1 may emit light during the second on-section, so that images having different grayscales may be displayed. For example, as the second on-section increases, an image having a higher grayscale may be displayed.

[0186] Meanwhile, the first light-emitting circuit 130-1 may comprise 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 control switch 131-1 to the fourth control switch 134-1 may be turned on / off in response to the first control signal CSA to the fourth control signal CSD, respectively.

[0187] The first control switch 131-1 may be connected between the first transistor T11 and the second power line 142, and the second control switch 132-1 may be connected between the first transistor T11 and the measurement line 145.

[0188] The third control switch 133-1 may be connected between the first light-emitting element 120-1 and the first transistor T11, and the fourth control switch 134-1 may be connected between the third power line 143 and the first transistor T11.

[0189] The first control switch 131-1 may comprise a second transistor T14, and the second control switch 132-1 may comprise a third transistor T15. The third control switch 133-1 may comprise a fourth transistor T16, and the fourth control switch 134-1 may comprise a fifth transistor T17.

[0190] The second transistor T14 and the third transistor T15 may comprise, but are not limited to, NMOS transistors. The second transistor T14 may be turned on in response to a first control signal CSA of a high level. The third transistor T15 may be turned on in response to the second control signal CSB of a high level.

[0191] The fourth transistor T16 and the fifth transistor T17 may comprise PMOS transistors, but are not limited thereto. The fourth transistor T16 may be turned on in response to the third control signal CSC of a low level. The fifth transistor T17 may be turned on in response to the fourth control signal CSD of a low level.

[0192] Meanwhile, 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 may be turned on or turned off simultaneously by the first control signal CSA. When 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 may be turned on simultaneously in response to the first control signal CSA of a high level.

[0193] 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 may be turned on simultaneously or turned off simultaneously by the second control signal CSB. In the case where 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 are NMOS transistors, 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 may be turned on simultaneously in response to the second control signal CSB of a high level.

[0194] As an example, the first control switch 131-1 may be turned on and the second control switch 132-1 may be turned off, so that the first transistor T11 may be connected to the second power line 142, but may be 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 current IEM1 may be generated in the first light-emitting circuit 130-1.

[0195] As another example, the first control switch 131-1 may be turned off and the second control switch 132-1 may be turned on, so that the first transistor T11 may be connected to the measurement line 145 but may be electrically disconnected from the second power line 142. In this instance, the first light-emitting current IEM1 when emitting or the non-light-emitting current when not light-emitting may be output through the measurement line 145. The first light-emitting current IEM1 may be a current for emitting the first light-emitting element 120-1. The non-light-emitting current may be a current generated in the first light-emitting circuit 130-1 between the third power line 143 and the second power line 142. The non-light-emitting current may be different from the first light-emitting current IEM1.

[0196] For example, 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 current IEM1 generated in the first transistor T11 of the first light-emitting circuit 130-1 between the first power line 141 and the measurement line 145 may be output through the measurement line 145 to emit light in the first light-emitting element 120-1. 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 and SW12-2 are turned on, the non-light-emitting current generated in the first transistor T11 of the first light-emitting circuit 130-1 between the third power line 143 and the measurement line 145 may be output through the measurement line 145.

[0197] Meanwhile, various currents may be measured through the turning on / off of 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 to the fourth control switch 134-1 of the first light-emitting circuit 130-1. The various currents may be measured by the current measurement circuit (170 of FIG. 2).

[0198] As a first example, the reference current IREF generated in the reference current generation circuit 110 as in mathematical formula 3 may be measured as the measurement result (I M1 ). I M 1 = IREF

[0199] As a second example, the reference current IREF and the specific light-emitting current may be measured as the measurement result (I M2 ) while a specific light-emitting element is emitting as in mathematical formula 4. I M 2 = IREF + IEM # _ ON

[0200] IEM#_ON may represent the light-emitting current generated in a specific light-emitting circuit that is to be measured while emitting a specific light-emitting element among a plurality of light-emitting circuits (130-1 to 130-N in FIG. 2).

[0201] For example, the measurement result (I M2 ) may be the sum of the reference current IREF and the specific light-emitting current, but is not limited thereto.

[0202] As a third example, while a specific light-emitting element does not emit light, the reference current IREF and a specific non-emitting current may be measured as a measurement result (I M3 ) as in Equation 5. I M 3 = IREF + IEM # _ OFF

[0203] IEM#_OFF may represent a non-emitting current generated in a specific light-emitting circuit to be measured that a specific light-emitting element does not emit light among a plurality of light-emitting circuits (130-1 to 130-N in FIG. 2).

[0204] For example, the measurement result (I M3 ) may be the sum of the reference current IREF and a specific non-emitting current, but is not limited thereto.

[0205] For example, by using the measurement results (I M1 , I M2 , I M3 ) represented in each of Equations 3 to 5, the reference voltage control circuit of the voltage generation circuit 150 and / or the reference current adjustment circuit 115 of the reference current generation circuit 110 may be controlled, thereby adjusting the plurality of light-emitting currents IEM1 to IEMN of the plurality of light-emitting circuits 130-1 to 13-N. Accordingly, the uniformity of current between the plurality of ICs (the first IC) may be secured, so that the image quality can be improved.

[0206] The operation of obtaining the measurement results (I M1 , I M2 , I M3 ) represented in Equations 3 to 5 is described in detail with reference to FIGS. 5 to 7.

[0207] According to the embodiment, since the first light-emitting circuit 130-1 is not equipped with a capacitor, it is not subject to area constraints, so that the aperture ratio can be increased, thereby improving the luminance.

[0208] According to the embodiment, since a display driving device comprising a converter that converts digital data into analog data is not required, the circuit structure can be simplified, the occupied area can be reduced, and the cost can be reduced.

[0209] According to the embodiment, since the reference current IREF is adjusted differently from each other, accurate luminance adjustment is possible at any time.

[0210] According to the embodiment, luminance adjustment between display screens is easy through switching of a plurality of selection switches 112-1 provided in the reference current adjustment circuit 115.

[0211] According to the embodiment, a plurality of different reference voltages VREF may be provided in the voltage generation circuit 150, and a plurality of different reference currents IREF may be generated based on the plurality of reference voltages VREF, respectively, in the reference current generation circuit 110. In this instance, a first light-emitting circuit 130-1 may generate a first light-emitting current IEM1 that is different from each other based on a plurality of different reference currents IREF.

[0212] For example, when three selection switches 156-1 are provided in the voltage generation circuit 150, (2 3< -1) = 7 different reference voltages VREF may be provided. For example, when four selection switches 112-1 are provided in the reference current adjustment circuit 115 of the reference current generation circuit 110, (2 4< -1) = 15 different reference currents IREF may be generated. In this instance, each of the first light-emitting circuits 130-1 may generate (7*15) = 105 different first light-emitting currents IEM1.

[0213] Therefore, since the transistors T32-1, T33-1, T22-1 and T23-1 are provided to adjust the reference voltage VREF and / or the reference current IREF in the voltage generation circuit 150 and / or the reference current generation circuit 110, the desired luminance may be accurately obtained through a number of different first light-emitting currents IEM1, so that the image quality can be dramatically improved.

[0214] According to an embodiment, the measurement line 145 may be connected to the reference current generation circuit 110 and the plurality of light-emitting circuits 130-1 to 130-N, so that the reference current generated by the reference current generation circuit 110, the plurality of light-emitting currents IEM1 to IEMN generated by the plurality of light-emitting circuits 130-1 to 130-N or the non-light-emitting current may be measured. By using the current measured in this way, the voltage generation circuit 150 or the reference current generation circuit 110 may be controlled, so that the uniformity of the light-emitting current between displays or blocks, i.e., the uniformity of the luminance, may be secured. Here, the block may be a circuit configuration unit as illustrated in FIG. 2, and a plurality of blocks may be provided on the display panel.[Light-emitting mode]

[0215] FIG. 4 illustrates a display device according to a second embodiment operating in light-emitting mode.

[0216] As illustrated in FIG. 4, display operation may be performed according to the switching of the control switch, so that the voltage generation circuit 150, the reference current generation circuit 110, and the light-emitting circuit may be operated.

[0217] Specifically, in response to a control signal EC of a high level, the control switch 151-1 may be turned on and the control switch 151-2 may be turned off, so that the voltage generation circuit 150 may be operated. The threshold voltage of at least one or more second transistor T32-1 selected in response to the plurality of selection switches 156-1 of the reference voltage adjustment circuit being turned on / off and the reference voltage VREF adjusted by the first transistor T31 may be output.

[0218] Meanwhile, to be operated in the light-emitting mode, the first control switch 116 and the third control switches 113-1 and 113-2 in the reference current generation circuit 110 may be turned on and the second control switch 117 may be turned off. In this instance, the first transistor T21 of the reference current generation circuit 110 may be electrically connected to the second power line 142, but may be disconnected from the measurement line 145. Accordingly, the reference current adjustment circuit 115 of the reference current generation circuit 110 may generate a reference current IREF adjusted by at least one or more constant current source 111-1 selected in response to the plurality of selection switches 156-1 being turned on / off based on the adjusted reference voltage VREF.

[0219] In addition, 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 may be turned on, and the second control switch 132-1 and the fourth control switch 134-1 may be turned off. In this instance, the first transistor T11 of the first light-emitting circuit 130-1 may be electrically connected to the second power line 142, but may be disconnected from the measurement line 145. A first light-emitting current IEM1 corresponding to the reference current IREF generated by the reference current generation circuit 110 may be generated in the first transistor T11 of the first light-emitting circuit 130-1 and supplied to the first light-emitting element 120-1. Accordingly, the first light-emitting element 120-1 may emit light by the first light-emitting current IEM1.

[0220] Although not shown, the first control switch, the third control switch, and the fifth control switch SW11, SW12-1, and SW12-2 of the second to Nth light-emitting circuits ((130-2 to 130-N of FIG. 2) respectively) may be turned on, and the second control switch and the fourth control switch may be turned off. Accordingly, the second to Nth light-emitting elements may be emitted by the second to Nth light-emitting currents generated in the second to Nth light-emitting circuits 130-2 to 130-N, respectively.[Reference current measurement mode]

[0221] FIG. 5 illustrates a display device according to a second embodiment that operates in the reference current measurement mode.

[0222] As illustrated in FIG. 5, display operation may be performed according to the switching of the control switches, so that the voltage generation circuit 150, the reference current generation circuit 110, and the first light-emitting circuit 130-1 may be operated. Accordingly, the reference voltage VREF adjusted in the voltage generation circuit 150 may be output through the X node, the reference current generation circuit 110 may generate the reference current IREF adjusted using at least one constant current based on the reference voltage VREF, and the first light-emitting circuit 130-1 may generate the first light-emitting current IEM1 corresponding to the reference current IREF to emit light in the first light-emitting element 120-1.

[0223] Meanwhile, to operate in the reference current measurement mode, the first control switch 116 in the reference current generation circuit 110 may be turned off and the second control switch 117 and the third control switches 113-1 and 113-2 may be turned on. In this instance, the first transistor T21 of the reference current generation circuit 110 may be electrically connected to the measurement line 145, but may be disconnected from the second power line 142. Accordingly, the reference current IREF may be output from the reference current generation circuit 110 through the measurement line 145. The current measurement circuit (170 in Fig. 2) may obtain the reference current IREF as a measurement result through the measurement line 145, as shown in mathematical formula 3.

[0224] In addition, the fifth control switches SW11, SW12-1, and SW12-2 in the first light-emitting circuit 130-1 may be turned off. In this instance, the first light-emitting element 120-1 or the third power line 143 may be electrically disconnected from the second power line 142 or the measurement line 145, so that the first light-emitting current or the non-light-emitting current may be not generated or output through the measurement line 145. At this time, the first control switch 131-1 to the fourth control switch 134-1 may be turned on or off.

[0225] Although not shown, the fifth control switches SW11, SW12-1 and SW12-2 of the second light-emitting circuit (130-2 in FIG. 2) to the Nth light-emitting circuit 130-N may be turned off. Accordingly, the second light-emitting current to the Nth light-emitting current or the non-light-emitting current may be not generated or output through the measurement line 145 in the second light-emitting circuit 130-2 to the Nth light-emitting circuit 130-N, respectively.[Light-emitting current measurement mode]

[0226] FIG. 6 illustrates a display device according to the second embodiment operating in the light-emitting current measurement mode.

[0227] As illustrated in FIG. 6, display operation may be performed according to the switching of the control switch, so that the voltage generation circuit 150, the reference current generation circuit 110 and the first light-emitting circuit 130-1 may be operated. Accordingly, the reference voltage VREF adjusted by the voltage generation circuit 150 may be output through the node X, the reference current generation circuit 110 may generate the reference current IREF adjusted using at least one or more constant current based on the reference voltage VREF, and the first light-emitting circuit 130-1 may generate the first light-emitting current IEM1 corresponding to the reference current IREF to emit light from the first light-emitting element 120-1.

[0228] Meanwhile, to operate in the light-emitting current measurement mode, the first control switch 116 in the reference current generation circuit 110 may be turned off and the second control switch 117 and the third control switches 113-1 and 113-2 may be turned on. In this instance, the first transistor T21 of the reference current generation circuit 110 may be electrically connected to the measurement line 145, but may be disconnected from the second power line 142. Accordingly, the reference current IREF generated in the reference current generation circuit 110 may be output through the measurement line 145.

[0229] In addition, in the first light-emitting circuit 130-1, the first control switch 131-1 and the fourth control switch 134-1 may be turned off, and the second control switch 132-1, the third control switch 133-1, and the fifth control switches SW11, SW12-1, and SW12-2 may be turned on. The first light-emitting circuit 130-1 may be a light-emitting circuit to be measured. In this instance, the first transistor T11 may be connected to the measurement line 145, but may be electrically disconnected from the second power line 142. Accordingly, the first light-emitting current IEM1 generated in the first light-emitting circuit 130-1 may be output through the measurement line 145.

[0230] The fifth control switches SW11, SW12-1, and SW12-2 of each of the remaining light-emitting circuits that are not the measurement target, i.e., the second light-emitting circuit to the Nth light-emitting circuit, may be turned off. Accordingly, the second light-emitting current to the Nth light-emitting current or the non-light-emitting current are not generated or output through the measurement line 145 in each of the second light-emitting circuit 130-2 to the Nth light-emitting circuit 130-N.

[0231] Accordingly, the reference current IREF generated (or adjusted) in the reference current generation circuit 110 and the first light-emitting current IEM1 generated (or adjusted) in the first light-emitting circuit 130-1 may be output through the measurement line 145. The current measurement circuit (170 of FIG. 2) may obtain the sum of the reference current IREF and the first light-emitting current IEM1 as a measurement result through the measurement line 145, as represented in mathematical formula 4. In this instance, the measurement result represented in the mathematical formula 3 may be subtracted from the measurement result represented in the mathematical formula 4, so that the first light-emitting current IEM1 generated in the first light-emitting circuit 130-1 may be measured. This operation may be performed in the current measurement circuit (170 of FIG. 2) or the current control circuit 180, but is not limited thereto.[Non-light-emitting current measurement mode]

[0232] FIG. 7 illustrates a display device according to the second embodiment that operates in the non-light-emitting current measurement mode.

[0233] As illustrated in FIG. 7, display operation may be performed according to the switching of the control switch, so that the voltage generation circuit 150, the reference current generation circuit 110, and the first light-emitting circuit 130-1 may operate. Accordingly, the reference voltage VREF adjusted by the voltage generation circuit 150 may be output through the node X, the reference current generation circuit 110 may generate the reference current IREF adjusted using at least one or more constant current based on the reference voltage VREF, and the first light-emitting circuit 130-1 may generate the first light-emitting current IEM1 corresponding to the reference current IREF to emit light from the first light-emitting element 120-1.

[0234] Meanwhile, to operate in a non-light-emitting current measurement mode, the first control switch 116 in the reference current generation circuit 110 may be turned off and the second control switch 117 and the third control switches 113-1 and 113-2 may be turned on. In this instance, the first transistor T21 of the reference current generation circuit 110 may be electrically connected to the measurement line 145, but may be disconnected from the second power line 142. Accordingly, the reference current IREF generated in the reference current generation circuit 110 may be output through the measurement line 145.

[0235] In addition, in the first light-emitting circuit 130-1, the first control switch 131-1 and the third control switch 133-1 may be turned off, and the second control switch 132-1, the fourth control switch 134-1, and the fifth control switches SW11, SW12-1, and SW12-2 may be turned on. The first light-emitting circuit 130-1 may be a light-emitting circuit to be measured. In this instance, the first transistor T11 may be connected to the measurement line 145, but may be electrically disconnected from the second power line 142. Accordingly, the non-light-emitting current INEM generated in the first transistor T11 of the first light-emitting circuit 130-1 between the third power line 143 and the measurement line 145 may be output through the measurement line 145. At this time, since the third control switch 133-1 is turned off, the first light-emitting element 120-1 does not emit light.

[0236] The fifth control switches SW11, SW12-1, and SW12-2 of each of the remaining light-emitting circuits that are not the measurement target, i.e., the second light-emitting circuit to the Nth light-emitting circuit, may be turned off. Accordingly, the second light-emitting current to the Nth light-emitting current or the non-light-emitting current INEM may be not generated in each of the second light-emitting circuit 130-2 to the Nth light-emitting circuit 130-N, or may be not output through the measurement line 145.

[0237] Accordingly, the reference current IREF generated (or adjusted) in the reference current generation circuit 110 and the non-light-emitting current INEM generated (or adjusted) in the first light-emitting circuit 130-1 may be output through the measurement line 145. The current measurement circuit (170 of FIG. 2) may obtain the sum of the reference current IREF and the non-light-emitting current INEM as a measurement result through the measurement line 145, as represented in mathematical formula 5. In this instance, the non-light-emitting current INEM generated in the first light-emitting circuit 130-1 may be measured by subtracting the measurement result represented in mathematical expression 3 from the measurement result represented in mathematical expression 5. This operation may be performed in the current measurement circuit (170 in FIG. 2) or the current control circuit 180, but is not limited thereto.[Third embodiment]

[0238] FIG. 8 is a block diagram illustrating a display device according to a third embodiment.

[0239] The third embodiment is the same as the second embodiment (FIG. 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 as well) may be independently switching-controlled using individual control signals CSC-1, CSC-2, CSD-1, and CSD-2. In the third embodiment, the same reference numerals are given to components having the same circuit structure or function as those of the second embodiment (FIG. 3), and detailed descriptions thereof are omitted.

[0240] As illustrated in FIG. 8, the reference current generation circuit 110 may comprise a first control switch 116, a second control switch 117, a third control switches 113-1 and 113-2, etc. The first light-emitting circuit 130-1 may comprise a first control switch 131-1, a second control switch 132-1, a third control switch 133-1, a fourth control switch 134-1, and fifth control switches SW11, SW12-1, and SW12-2, etc.

[0241] 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 may be independently turned on / off.

[0242] The first control switch 116 and the second control switch 117 of the reference current generation circuit 110 may be independently turned on / off in response to the control signals CSE and CSF. In response to a control signal CSE of a high-level , a first control switch 116 of the reference current generation circuit 110 may be turned on. In response to a control signal CSF of a high-level , a second control switch 117 of the reference current generation circuit 110 may be turned on.

[0243] 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 may be independently turned on / off in response to the control signals CSA, CSB, CSC, and CSD. The first control switch 131-1 of the first light-emitting circuit 130-1 may be turned on in response to a control signal CSA of a high-level. The second control switch 132-1 of the first light-emitting circuit 130-1 may be turned on in response to a control signal CSB of a high-level. The third control switch 133-1 of the first light-emitting circuit 130-1 may be turned on in response to a control signal CSC of a high-level. The fourth control switch 134-1 of the first light-emitting circuit 130-1 may be turned on in response to a control signal CSD of a high-level.

[0244] In this way, more diverse current measurements may be possible by using more control signals CSA, CSB, CSC, CSD, CSE, and CSF than in the second embodiment (FIG. 3).

[0245] As an example, as described above, the light-emitting current or the non-light-emitting current generated in at least one or more light-emitting circuit among the plurality of light-emitting circuits (130-1 to 130-N of FIG. 2) may be measured as the measurement result (I M4 ) as in the mathematical formula 6. I M 4 = IEM #

[0246] IEM# may represent the light-emitting current or the non-light-emitting current generated in at least one or more light-emitting circuit among the plurality of light-emitting circuits 130-1 to 130-N.

[0247] For example, the light-emitting current or the non-light-emitting current generated in one light-emitting circuit may be measured as a measurement result (I M4 ).

[0248] For example, the light-emitting current or the non-light-emitting current generated in two or more light-emitting circuits may be measured as a measurement result (I M4 ). In this instance, the measurement result (I M4 ) may be the sum of light-emitting currents generated in two or more light-emitting circuits or the sum of non-light-emitting currents generated in two or more light-emitting circuits.[Reference current measurement mode when light-emitting]

[0249] FIG. 9 illustrates a display device according to the third embodiment that operates in a reference current measurement mode when light-emitting.

[0250] As illustrated in FIG. 9, the display operation may be performed according to the switching of the control switch, so that the voltage generation circuit 150, the reference current generation circuit 110, and the first light-emitting circuit 130-1 may be operated. Accordingly, the reference voltage VREF adjusted by the voltage generation circuit 150 may be output through the node X, the reference current generation circuit 110 may generate the reference current IREF adjusted using at least one or more constant current based on the reference voltage VREF, and the first light-emitting circuit 130-1 may generate the first light-emitting current IEM1 corresponding to the reference current IREF to emit light from the first light-emitting element 120-1.

[0251] Meanwhile, to operate in the reference current measurement mode when light-emitting, the first control switch 116 in the reference current generation circuit 110 may be turned off, and the second control switch 117 and the third control switches 113-1 and 113-2 may be turned on. In this instance, the first transistor T21 of the reference current generation circuit 110 may be electrically connected to the measurement line 145, but may be disconnected from the second power line 142. Accordingly, the reference current IREF may be output from the reference current generation circuit 110 through the measurement line 145. The current measurement circuit (170 of FIG. 2) may obtain the reference current IREF as a measurement result through the measurement line 145, as represented in mathematical formula 3.

[0252] In addition, 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 may be turned on, and the second control switch 132-1 and the fourth control switch 134-1 may be turned off. In this instance, the first light-emitting current IEM1 generated in the first transistor T11 of the first light-emitting circuit 130-1 may be generated between the first power line 141 and the second power line 142 to emit light from the first light-emitting element 120-1.

[0253] Although not illustrated, the first control switch, the third control switch, and the fifth control switches SW11, SW12-1, and SW12-2 of each of the second light-emitting circuit (130-2 in FIG. 2) to the Nth light-emitting circuit 130-N may be turned on, and the second control switch and the fourth control switch may be turned off. Accordingly, the second light-emitting element to the Nth light-emitting element may be emitted by the second light-emitting current to the Nth light-emitting current generated in each of the second light-emitting circuit 130-2 to the Nth light-emitting circuit 130-N.

[0254] As illustrated in FIG. 9, even if the first light-emitting element 120-1 normally emits light by the first light-emitting circuit 130-1, the reference current IREF generated by the reference current generation circuit 110 may be measured.[Reference current measurement mode when not light-emitting]

[0255] FIG. 10 illustrates a display device according to the third embodiment that operates in the reference current measurement mode when not light-emitting.

[0256] As illustrated in FIG. 10, display operation may be performed according to the switching of the control switch, so that the voltage generation circuit 150, the reference current generation circuit 110, and the first light-emitting circuit 130-1 may operate. Accordingly, the reference voltage VREF adjusted by the voltage generation circuit 150 may be output through the node X, the reference current generation circuit 110 may generate the reference current IREF adjusted using at least one or more constant current based on the reference voltage VREF, and the first light-emitting circuit 130-1 may generate the first light-emitting current IEM1 corresponding to the reference current IREF to emit light from the first light-emitting element 120-1.

[0257] Meanwhile, to operate in the reference current measurement mode when not light-emitting, the first control switch 116 in the reference current generation circuit 110 may be turned off and the second control switch 117 and the third control switches 113-1 and 113-2 may be turned on. In this instance, the first transistor T21 of the reference current generation circuit 110 may be electrically connected to the measurement line 145, but may be disconnected from the second power line 142. Accordingly, the reference current IREF may be output through the measurement line 145 in the reference current generation circuit 110. The current measurement circuit (170 in FIG. 2) may obtain the reference current IREF as a measurement result through the measurement line 145, as represented in mathematical formula 3.

[0258] In addition, 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, and SW12-2 may be turned on, and the second control switch 132-1 and the third control switch 133-1 may be turned off. In this instance, a non-light-emitting current INEM may be generated in the first transistor T11 of the first light-emitting circuit 130-1 between the third power line 143 and the second power line 142. Since the third control switch 133-1 is turned off, the first light-emitting element 120-1 does not emit light.

[0259] Although not illustrated, the second light-emitting current to the Nth light-emitting current or the non-light-emitting current INEM may be generated in each of the second light-emitting circuit (130-2 of FIG. 2) to the Nth light-emitting circuit 130-N.

[0260] As illustrated in FIG. 10, even if the first light-emitting element 120-1 does not emit light by the first light-emitting circuit 130-1, the reference current IREF generated by the reference current generation circuit 110 may be measured.

[0261] From the description of FIG. 9 and FIG. 10, the reference current IREF may be measured regardless of the light-emission of the first light-emitting element 120-1 by the first light-emitting circuit 130-1. From this, it may be seen that the reference current IREF may be measured regardless of the emission section or non-emission section of one period (or one frame).[Light-emitting current measurement mode when light-emitting]

[0262] FIG. 11 illustrates a display device according to the third embodiment that operates in the light-emitting current measurement mode when light-emitting.

[0263] As illustrated in FIG. 11, the display operation may be performed according to the switching of the control switch, so that the voltage generation circuit 150, the reference current generation circuit 110, and the first light-emitting circuit 130-1 may be operated. Accordingly, the reference voltage VREF adjusted by the voltage generation circuit 150 may be output through the node X, the reference current generation circuit 110 may generate the reference current IREF adjusted using at least one or more constant current based on the reference voltage VREF, and the first light-emitting circuit 130-1 may generate the first light-emitting current IEM1 corresponding to the reference current IREF to emit light from the first light-emitting element 120-1.

[0264] Meanwhile, to operate in the light-emitting current measurement mode when light-emitting, the first control switch 116 and the third control switches 113-1 and 113-2 in the reference current generation circuit 110 may be turned on and the second control switch 117 may be turned off. In this instance, the first transistor T21 of the reference current generation circuit 110 may be electrically connected to the second power line 142, but may be electrically disconnected from the measurement line 145. Accordingly, the reference current IREF may be generated in the first transistor T21 of the reference current generation circuit 110 between the third power line 143 and the second power line 142.

[0265] In addition, in the first light-emitting circuit 130-1, the first control switch 131-1 and the fourth control switch 134-1 may be turned off, and the second control switch 132-1, the third control switch 133-1, and the fifth control switches SW11, SW12-1, and SW12-2 may be turned on. In this instance, the first transistor T11 of the first light-emitting circuit 130-1 may be connected to the measurement line 145, but may be electrically disconnected from the second power line 142. Accordingly, the first light emitting current IEM1 generated in the first transistor T11 of the first light emitting circuit 130-1 between the first power line 141 and the measurement line 145 to emit light from the first light emitting element 120-1 may be output through the measurement line 145.

[0266] Although not illustrated, the first control switch and the fourth control switch of at least one or more light-emitting circuit among the second light-emitting circuit (130-2 of FIG. 2) to the Nth light-emitting circuit 130-N may be turned off, and the second control switch, the third control switch, and the fifth control switches SW11, SW12-1, and SW12-2 may be turned on, so that the light-emitting current generated in the corresponding light-emitting circuit may be output through the measurement line 145.

[0267] As illustrated in FIG. 11, even if the first light-emitting element 120-1 is normally emitted by the first light-emitting circuit 130-1, the first light-emitting current IEM1 generated by the first light-emitting circuit 130-1 may be measured as a measurement result as represented in mathematical formula 6. At this time, in mathematical formula 6, IEM# may represent the first light-emitting current IEM1 generated by the first light-emitting circuit 130-1.

[0268] At the same time, two or more light-emitting currents generated by two or more light-emitting circuits may be measured as a measurement result as represented in mathematical formula 6. At this time, the measurement result may be the sum of two or more light-emitting currents.[Non-light-emitting current measurement mode when not light-emitting]

[0269] FIG. 12 illustrates a display device according to the third embodiment that operates in a non-light-emitting current measurement mode when not light-emitting.

[0270] As illustrated in FIG. 12, the display operation may be performed according to the switching of the control switch, so that the voltage generation circuit 150, the reference current generation circuit 110, and the first light-emitting circuit 130-1 may be operated. Accordingly, the reference voltage VREF adjusted by the voltage generation circuit 150 may be output through the node X, the reference current generation circuit 110 may generate the reference current IREF adjusted using at least one or more constant current based on the reference voltage VREF, and the first light-emitting circuit 130-1 may generate the first light-emitting current IEM1 corresponding to the reference current IREF to emit light from the first light-emitting element 120-1.

[0271] Meanwhile, to operate in the non-light-emitting current measurement mode when not light-emitting, the first control switch 116 and the third control switches 113-1 and 113-2 in the reference current generation circuit 110 may be turned on and the second control switch 117 may be turned off. In this instance, the first transistor T21 of the reference current generation circuit 110 may be electrically connected to the second power line 142, but may be electrically disconnected from the measurement line 145. Accordingly, the reference current IREF may be generated in the first transistor T21 of the reference current generation circuit 110 between the third power line 143 and the second power line 142.

[0272] In addition, in the first light-emitting circuit 130-1, the first control switch 131-1 and the third control switch 133-1 may be turned off, and the second control switch 132-1, the fourth control switch 134-1, and the fifth control switches SW11, SW12-1, and SW12-2 may be turned on. In this instance, the first transistor T11 of the first light-emitting circuit 130-1 may be connected to the measurement line 145, but may be electrically disconnected from the second power line 142. Accordingly, the non-light-emitting current INEM generated in the first transistor T11 of the first light-emitting circuit 130-1 between the third power line 143 the measurement line 145 may be output through the measurement line 145.

[0273] Although not shown, the first control switch and the fourth control switch of at least one or more light-emitting circuit among the second light-emitting circuit (130-2 of FIG. 2) to the Nth light-emitting circuit 130-N may be turned off, and the second control switch, the third control switch, and the fifth control switches SW11, SW12-1, and SW12-2 may be turned on, so that the non-light-emitting current INEM generated in the corresponding light-emitting circuit may be output through the measurement line 145.

[0274] As illustrated in FIG. 12, even if the first light-emitting element 120-1 does not emit light by the first light-emitting circuit 130-1, the non-light-emitting current INEM generated by the first light-emitting circuit 130-1 may be measured as a measurement result as represented in mathematical formula 6. At this time, in mathematical formula 6, IEM# may represent the non-light-emitting current INEM generated by the first light-emitting circuit 130-1.

[0275] At the same time, two or more non-light-emitting currents INEM generated by two or more light-emitting circuits may also be measured as a measurement result as represented in mathematical formula 6. At this time, the measurement result may be the sum of two or more non-light-emitting currents INEM.

[0276] In the above, the voltage generation circuit 150, the reference current generation circuit 110, the first light-emitting circuit 130-1, and the plurality of light-emitting elements 120-1 to 120-N may be one block (or module), and the display device or display panel according to the first embodiment may be configured as a plurality of blocks. As another example, the voltage generation circuit 150 may not be included in the plurality of blocks but may be provided separately. In this instance, the voltage generation circuit 150 may be commonly connected to the plurality of blocks, and the reference voltage VREF may be provided to the reference current generation circuit 110 of each of the plurality of blocks.

[0277] The uniformity of the light-emitting current between displays or between blocks, i.e., the luminance uniformity, may be secured by using the reference current IREF, the light-emitting current or the non-light-emitting current INEM obtained by the various current measurement operations or methods described above.

[0278] The above detailed description should not be construed as limiting in all respects and should be considered illustrative. The scope of the embodiment should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent range of the embodiment are included in the scope of the embodiment.

Claims

1. A display device comprising a plurality of subpixels, comprising: a plurality of light-emitting elements provided in the 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 the plurality of subpixels and connected to the reference current generation circuit and the plurality of light-emitting elements, wherein the reference current generation circuit and the plurality of light-emitting circuits are commonly connected to a second power line, and wherein the reference current generation circuit and the plurality of light-emitting circuits are commonly connected to a measurement line.

2. The display device of claim 1, wherein the reference current generation circuit comprises: a first transistor; a first control switch between the first transistor and the second power line; and a second control switch between the first transistor and the measurement line.

3. The display device of claim 2, wherein each of the plurality of light-emitting circuits comprises: a first transistor constituting a mirror circuit with a first transistor of the reference current generation circuit; a first control switch between the first transistor and the second power line; and a second control switch between the first transistor and the measurement line.

4. The display device of claim 3, wherein the reference current generation circuit comprises: a third control switch connected to the first transistor to be on / off a reference current.

5. The display device of claim 4, wherein each of the plurality of light-emitting circuits comprises: a third control switch connected between the light-emitting element and the first transistor; a fourth control switch connected between the third power line and the first transistor and a fifth control switch connected to the first transistor to be on / off a light-emitting current.

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

7. The display device of claim 6, wherein in a 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 of the reference current generation circuit are turned on, and the fifth control switches of the plurality of light-emitting circuits are turned off.

8. The display device of claim 6, wherein in a light-emitting 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 of the reference current generation circuit are turned on, the first control switch and the fourth control switch of a light-emitting circuit to be measured among the plurality of light-emitting circuits are turned off, the second control switch, the third control switch and the fifth control switch of the light-emitting circuit to be measured are turned on, and the fifth control switches of the remaining light-emitting circuits among the plurality of light-emitting circuits are turned off.

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

10. The display device of claim 6, wherein in a reference current measurement mode when light-emitting, the first control switch of the reference current generation circuit is turned off, the second control switch and the third control switch of the reference current generation circuit are turned on, the first control switch, the third control switch and the fifth control switch of at least one or more light-emitting circuit among the plurality of light-emitting circuits are turned on, and the second control switch and the fourth control switch of the at least one or more light-emitting circuit are turned off.

11. The display device of claim 6, wherein in a reference current measurement mode when not light-emitting, the first control switch of the reference current generation circuit is turned off, the second control switch and the third control switch the reference current generation circuit are turned on, the first control switch, the fourth control switch and the fifth control switch of at least one or more light-emitting circuit among the plurality of light-emitting circuits are turned on, and the second control switch and the third control switch of the at least one or more light-emitting circuit are turned off.

12. The display device of claim 6, wherein in a light-emitting current measurement mode when light-emitting, the first control switch and the third control switch of the reference current generation circuit are turned on, the second control switch of the reference current generation circuit are turned off, the first control switch and the fourth control switch of at least one or more light-emitting circuit among the plurality of light-emitting circuits are turned off, and the second control switch, the third control switch and the fifth control switch of the at least one or more light-emitting circuit are turned on.

13. The display device of claim 6, wherein in a non-light-emitting current measurement mode when not light-emitting, the first control switch and the third control switch of the reference current generation circuit are turned on and the second control switch of the reference current generation circuit is turned off, the first control switch and the third control switch of at least one or more light-emitting circuit among the plurality of light-emitting circuits are turned off, and the second control switch, the fourth control switch and the fifth control switch of the at least one or more light-emitting circuit are turned on.

14. The display device of claim 1, further comprising: a current measurement circuit connected to the measurement line to measure at least one or more of a reference current or a light-emitting current; and a current control circuit configured to control at least one of the voltage generation circuit or the reference current generation circuit based on a measured current.

Images