Display apparatus

Abstract

This display apparatus may comprise: a plurality of light-emitting elements provided in a plurality of sub-pixels 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 sub-pixels 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 can all be connected to a second power line, and the reference current generation circuit and the plurality of light-emitting circuits can be all be connected to a measurement line.

Description

display device

[0001] The embodiment relates to a display device.

[0002] The display market is growing, and its range of applications is continuously expanding. Along with this expansion, product resolutions and features are diversifying.

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

[0004] Driver ICs used to drive display devices are designed specifically for their specific applications. Therefore, the design's application potential is limited, requiring a custom driver IC for each product.

[0005] Existing display devices employ various methods to ensure luminance uniformity. For example, internal compensation is performed by configuring a light-emitting circuit in each pixel (or subpixel), or external compensation is performed using a specific method.

[0006] Meanwhile, most of the circuit configurations for the operation of the light-emitting circuit have their own capacitors built into the light-emitting circuit, ensuring constant current characteristics.

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

[0008] As illustrated in Fig. 1, a conventional 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 the scan signal (SCAN), the data signal (VDATA) is supplied to the driving transistor (M1) via the scan transistor (M2). The driving transistor (M1) supplies a 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 the sensing control signal (SEN), the luminescence current flowing in the driving transistor (M1) is detected as a sensing signal (VSEN). The characteristics of the corresponding luminescence circuit are calibrated or compensated using the sensing signal (VSEN).

[0012] Meanwhile, the light-emitting circuit of an active matrix display device controls brightness using either pulse width modulation (PWM) itself or a PWM method utilizing pulse amplitude modulation (PAM). In these cases, a capacitor is necessarily included within each pixel (or subpixel).

[0013] If the light-emitting circuit is designed to have a capacitor inside every pixel, limitations such as area may arise, or additional problems may arise due to the capacitor inside each pixel.

[0014] Meanwhile, the luminance of light-emitting devices such as LEDs is determined by the value of the luminous current. Due to differences in manufacturing characteristics or environmental conditions, the value of the luminous current may vary, or the efficiency of the light-emitting device may vary significantly. In such cases, the luminance of the display must be constantly adjusted by an external device, such as a controller or display driver, outside the luminous circuit, thereby ensuring uniform luminance across the entire display screen, which is cumbersome. Furthermore, the value of the luminous current may need to be adjusted to match the luminance across display screens, but a solution to this problem has not yet been proposed.

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

[0016] Another object of the present invention is to provide a display device that provides a novel driving method.

[0017] Another object of the present invention is to provide a display device in which a capacitor is not provided in a light-emitting circuit.

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

[0019] Another object of the present invention is to provide a display device capable of efficiently measuring a reference current and / or a luminous current.

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

[0021] Another object of the present invention is to provide a display device capable of ensuring uniformity of luminous current, i.e., luminance uniformity, between displays (or frames) or between blocks.

[0022] The technical problems of the embodiment are not limited to those described in this article, but include those that can be understood through the description of the invention.

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

[0024] The above reference current generation circuit may include 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 include: a first transistor of the reference current generation circuit and a first transistor constituting a mirror 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 above reference current generation circuit may include a third control switch connected to the first transistor to turn on / off the reference current.

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

[0028] In the light-emitting mode, the first control switch and the third control switch of the reference current generating circuit may be turned on, the second control switch 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 may be turned off.

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

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

[0031] In the non-luminescent current measurement mode, the first control switch of the reference current generation circuit is turned off, the second control switch and the third control switch are turned on, the first control switch and the third control switch of 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 are turned on, and the fifth control switches of the remaining light-emitting circuits among the plurality of light-emitting circuits can be turned off.

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

[0033] In the reference current measurement mode in the non-luminous state, the first control switch of the reference current generation circuit may be turned off, the second control switch and the third control switch may be turned on, and the first control switch, the fourth control switch and the fifth control switch of at least one light-emitting circuit among the plurality of light-emitting circuits may be turned on, and the second control switch and the third control switch may be turned off.

[0034] In the luminescence current measurement mode during luminescence, the first control switch and the third control switch of the reference current generation circuit may be turned on, the second control switch may be turned off, the first control switch and the fourth control switch of at least one luminescence circuit among the plurality of luminescence circuits may be turned off, and the second control switch, the third control switch, and the fifth control switch may be turned on.

[0035] In the non-luminescent current measurement mode in the non-luminescent state, the first control switch and the third control switch of the reference current generation circuit may be turned on and the second control switch may be turned off, and the first control switch and the third control switch of at least one 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 may be turned on.

[0036] The display device may further include a current measuring circuit connected to the measurement line and measuring at least one of a reference current or a luminous current; and a current control circuit controlling at least one of a voltage generation circuit or the reference current generation circuit based on the measured current.

[0037] The effects of the display device according to the embodiment are 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 the brightness.

[0039] According to at least one of the embodiments, there is no need for a display driving device including a converter that converts digital data into analog data, which has the advantage of simplifying the circuit structure, reducing the occupied area, and reducing the cost.

[0040] According to at least one of the embodiments, there is an advantage in that the luminescence current for emitting light of the light-emitting element is adjusted differently, thereby enabling precise brightness control at any time.

[0041] According to at least one of the embodiments, there is an advantage that accurate brightness control is possible at any time by adjusting the reference current differently.

[0042] According to at least one of the embodiments, there is an advantage in that accurate brightness control is possible at any time by differently adjusting the reference voltage for controlling the reference current.

[0043] According to at least one of the embodiments, by simultaneously adjusting the reference voltage and the reference current, the number of different light-emitting currents increases, so that brightness adjustment becomes more precise and a high-quality image can be realized.

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

[0045] In at least one of the embodiments, in a plurality of blocks (or modules) each including a voltage generation circuit, a reference current generation circuit, and a plurality of light-emitting circuits, a reference voltage provided from the voltage generation circuit of each module and / or a reference current generated from the reference current generation circuit can be adjusted. Accordingly, uniformity of luminance of the light-emitting current generated from the light-emitting circuits between the modules can be secured.

[0046] In at least one of the embodiments, various currents, such as a reference current, a light-emitting current, and a non-light-emitting current, can be measured through a measurement line commonly connected to a reference current generation circuit and a light-emitting circuit. 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] Further scope of applicability of the embodiments will become apparent from the detailed description below. However, since various changes and modifications within the spirit and scope of the embodiments will be readily apparent to those skilled in the art, it should be understood that the detailed description and specific embodiments, such as preferred embodiments, are given by way of example only.

[0048] Figure 1 is a circuit diagram illustrating a conventional light-emitting circuit.

[0049] FIG. 2 is a block diagram illustrating a display device according to the first embodiment.

[0050] FIG. 3 is a block diagram illustrating a display device according to a second embodiment.

[0051] FIG. 4 illustrates a display device according to a second embodiment operating in a luminescent mode.

[0052] FIG. 5 illustrates a display device according to a second embodiment operating in a reference current measurement mode.

[0053] FIG. 6 illustrates a display device according to a second embodiment operating in a luminous current measurement mode.

[0054] FIG. 7 illustrates a display device according to a second embodiment operating in a non-luminous current measurement mode.

[0055] Fig. 8 is a block diagram illustrating a display device according to a third embodiment.

[0056] FIG. 9 illustrates a display device according to a third embodiment operating in a reference current measurement mode during light emission.

[0057] FIG. 10 illustrates a display device according to a third embodiment operating in a reference current measurement mode in a non-luminous state.

[0058] Fig. 11 illustrates a display device according to a third embodiment operating in a luminescence current measurement mode during luminescence.

[0059] FIG. 12 illustrates a display device according to a third embodiment operating in a non-luminous current measurement mode when not emitting light.

[0060] The sizes, shapes, and dimensions of components depicted in the drawings may differ from the actual components. Furthermore, even if the same components are depicted with different sizes, shapes, and dimensions across drawings, this is merely an example within the drawings, and the same components may have the same sizes, shapes, and dimensions across drawings.

[0061] Hereinafter, embodiments disclosed in the present specification will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or similar components will be given the same reference numbers and redundant descriptions thereof will be omitted. The suffixes 'module' and 'part' used for components in the following description are given or used interchangeably in consideration of the ease of writing the specification, and do not have distinct meanings or roles in themselves. In addition, the attached drawings are intended to make it easier to understand the embodiments disclosed in the present specification, and the technical ideas disclosed in the present specification are not limited by the attached drawings. In addition, when an element such as a layer, region, or substrate is referred to as existing 'on' another element, this includes that it may be directly on the other element or that other intermediate elements may exist therebetween.

[0062] Hereinafter, “~module”, “~part”, etc. may be composed of “~circuit” or “integrated circuit”. “~module”, “~part”, etc. may be used interchangeably with “~circuit” or “integrated circuit”.

[0063] [Example 1]

[0064] FIG. 2 is a block diagram illustrating a display device according to the first embodiment.

[0065] Referring to FIG. 2, the display device according to the first embodiment may include a reference current generation circuit (110), a plurality of light-emitting circuits (130-1 to 130-N), a plurality of light-emitting elements (120-1 to 120-N), etc.

[0066] A display device according to the first embodiment may include a display panel. The display panel may include a plurality of pixels. The display panel may include a plurality of subpixels (SP-1 to SP-N). A single pixel may include a plurality of subpixels (SP-1 to SP-N).

[0067] A display panel may include a display area including a plurality of pixels and a non-display area excluding the display area. In addition, in the display panel, the light-emitting area may be an area corresponding to each of the plurality of subpixels (SP-1 to SP-N), and the non-light-emitting area may be an area corresponding between the plurality of subpixels (SP-1 to SP-N).

[0068] 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 a light-emitting area.

[0069] For example, the voltage generation circuit (150), the reference current generation circuit (110), and the plurality of light-emitting circuits (130-1 to 130-N) can each be individually implemented as an IC.

[0070] As another example, the voltage generation circuit (150) and the reference current generation circuit (110) may be implemented as a single integrated IC. In this case, the integrated IC may be provided in a light-emitting area or a non-light-emitting area. A plurality of light-emitting circuits (130-1 to 130-N) may be provided together with a plurality of light-emitting elements (120-1 to 120-N) in a 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).

[0071] 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 a single integrated IC. In this case, the integrated IC may be provided in a non-light-emitting area, 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).

[0072] Although the drawing shows a plurality of subpixels (SP-1 to SP-N) arranged in a row along the horizontal direction, the plurality of subpixels (SP-1 to SP-N) may be arranged in a row along the vertical direction or in a matrix form.

[0073] A plurality of subpixels (SP-1 to SP-N) may be electrically connected to a first power line (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. A light emission current of at least one light emission circuit among a plurality of light emission circuits (130-1 to 130-N) of the plurality of subpixels (SP-1 to SP-N) may be measured through the measurement line (145).

[0074] The plurality of subpixels (SP-1 to SP-N) may include a plurality of red subpixels, a plurality of green subpixels, and a plurality of blue subpixels. A unit pixel may be formed by adjacent red subpixels, green subpixels, and blue subpixels. In the drawing, the first subpixel (SP-1) may be a red subpixel, the second subpixel (SP-2) may be a green subpixel, and the third subpixel (SP-3) may be a blue subpixel, but is not limited thereto.

[0075] The first subpixel (SP-1) can emit red light, the second subpixel (SP-2) can emit green light, and the third subpixel (SP-3) can emit blue light. In addition, the plurality of subpixels (SP-1 to SP-N) may further include a plurality of transparent subpixels that emit transparent light.

[0076] Each of the plurality of subpixels (SP-1 to SP-N) may include at least one light-emitting element (120-1 to 120-N). For example, a first subpixel may include at least one red light-emitting element for emitting red light. For example, a second subpixel may include at least one green light-emitting element for emitting green light. For example, a third subpixel may include at least one blue light-emitting element for emitting blue light. The plurality of light-emitting elements (120-1 to 120-N) may include an organic semiconductor light-emitting element, an inorganic semiconductor light-emitting element, a micro LED (hereinafter, μ-LED), a nano LED, or the like.

[0077] A plurality of light-emitting elements (120-1 to 120-N) may be commonly connected to a first power line (141). A 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.

[0078] A plurality of light-emitting circuits (130-1 to 130-N) can drive a plurality of light-emitting elements (120-1 to 120-N) of a plurality of subpixels (SP-1 to SP-N) to emit a plurality of color lights.

[0079] A plurality of light-emitting circuits (130-1 to 130-N) may be commonly connected to a second power line (142). A plurality of light-emitting circuits (130-1 to 130-N) may be commonly connected to a third power line (143). A plurality of light-emitting circuits (130-1 to 130-N) may be commonly connected to a measurement line (145).

[0080] A plurality of light-emitting circuits (130-1 to 130N) can generate light-emitting currents (IEM1 to IEMN) to be supplied to corresponding light-emitting elements (120-1 to 120-N) between a first power line (141) and a second power line (142). The light-emitting currents (IEM1 to IEMN) may be referred to as driving currents, luminance currents, etc.

[0081] For example, in the first subpixel (SP-1), the first light-emitting circuit (130-1) can 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) and drive at least the first light-emitting element (120-1) to emit a first color light. For example, in the second subpixel (SP-2), the second light-emitting circuit (130-2) can be electrically connected to at least one second light-emitting element (120-2) to supply a second light-emitting current (IEM2) to the second light-emitting element (120-2) and drive the second light-emitting element (120-2) to emit a second color light. In the third subpixel (SP-3), the third light-emitting circuit (130-3) is electrically connected to the third light-emitting element (120-3), and a third light-emitting current (IEM3) is supplied to the third light-emitting element (120-3) to drive the second light-emitting element (120-3) to emit a 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 this is not limited thereto.

[0082] Meanwhile, a plurality of light-emitting circuits (130-1 to 130N) can individually or simultaneously output light-emitting currents (IEM1 to IEMN) through the measurement line (145). The output currents (IEM1 to IEMN) can be measured by a current measuring circuit (170) to be described later.

[0083] Meanwhile, the reference current generation circuit (110) can generate a reference current (IREF). The reference current generation circuit (110) can be commonly connected to a plurality of subpixels (SP-1 to SP-N).

[0084] The reference current (IREF) can be used to generate multiple emission currents (IEM1 to IEMN) that flow to multiple subpixels (SP-1 to SP-N). That is, the reference current (IREF) generated in the reference current generation circuit (110) can be copied to the plurality of subpixels (SP-1 to SP-N), so that the light emission currents (IEM1 to IEMN) can be generated in each subpixel (SP-1 to SP-N). For example, the light emission currents (IEM1 to IEMN) corresponding to the reference current (IREF) can be generated in each subpixel (SP-1 to SP-N) using a current mirror method. To this end, a current mirror circuit can 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 emission circuits (130-1 to 130-N). At least one transistor of the reference current generation circuit (110) can be diode-connected. The gate of at least one transistor of the reference current generation circuit (110) and the gate of at least one transistor of each of the plurality of light emission circuits (130-1 to 130-N) can be commonly connected to the G node.

[0085] The reference current (IREF) and the emission current (IEM1 to IEMN) can be constant currents. Constant current can mean that a constant current flows even when the voltage applied to both terminals changes.

[0086] The luminescent current (IEM1 to IEMN) may be a current corresponding to the reference current (IREF). The luminescent current (IEM1 to IEMN) may be equal to or greater than the reference current (IREF). That is, the plurality of luminescent circuits (130-1 to 130-N) may generate luminescent currents (IEM1 to IEMN) equal to or greater than the reference current (IREF) according to a preset ratio, i.e., a radiation ratio.

[0087] By designing the aspect ratio of each transistor 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), the radiation ratio can be determined.

[0088] For example, when the aspect ratio of the transistors of the light-emitting circuits (130-1 to 130-N) is the same as the aspect ratio of the transistors of the reference current generating circuit (110), the radiation ratio is 1, and thus the light-emitting currents (IEM1 to IEMN) generated in the plurality of light-emitting circuits (130-1 to 130-N) can be the same as the reference current (IREF). For example, when the aspect ratio of the transistors of the light-emitting circuits (130-1 to 130-N) is greater than the aspect ratio of the transistors of the reference current generating circuit (110), the radiation ratio has a value greater than 1, and thus the light-emitting currents (IEM1 to IEMN) generated in the light-emitting circuits (130-1 to 130-N) can be greater than the reference current (IREF).

[0089] Accordingly, by freely designing the aspect ratio of each transistor of a plurality of light-emitting circuits (130-1 to 130-N), the light-emitting current (IEM1 to IEMN) required in the corresponding subpixel (SP-1 to SP-N) can be accurately and easily obtained.

[0090] According to an embodiment, by using a copy ratio, the aspect ratio of the transistors of the reference current generation circuit (110) is 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) can generate a relatively small reference current (IREF). Accordingly, the burden of generating a large reference current (IREF) is reduced, the size of the reference current generation circuit (110) is 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 brightness can be implemented.

[0091] Meanwhile, the reference current generation circuit (110) can be electrically connected to the third power line (143), the second power line (142), and the measurement line (145).

[0092] The third power line (143) can 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) can be commonly connected to the reference current generation circuit (110) and the plurality of light-emitting circuits (130-1 to 130-N).

[0093] The measuring line (145) can be commonly connected to the reference current generation circuit (110) and a plurality of light emitting circuits (130-1 to 130-N).

[0094] Accordingly, the reference current (IREF) generated in the reference current generation circuit (110) can be measured through the measurement line (145), or a plurality of light-emitting currents (IEM1 to IEMN) generated in a plurality of light-emitting circuits (130-1 to 130-N) can 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) can be generated in the light-emitting circuits (130-1 to 130-N).

[0095] In addition, non-luminous current generated from multiple light-emitting circuits (130-1 to 130-N) can 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-luminous current can be generated from the light-emitting circuits (130-1 to 130-N).

[0096] A third power supply voltage (PVDD) may be supplied to a third power supply line (143). The third power supply voltage (PVDD) is a high-potential voltage and may be similar to the first power supply voltage (EVDD). For example, the third power supply voltage (PVDD) may be lower than the first power supply voltage (EVDD), but this is not limited thereto.

[0097] 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) constituting the current mirror circuit and the plurality of transistors of the plurality of light-emitting circuits (130-1 to 130-N) can commonly use the second power voltage (EVSS) supplied to the second power line (142). Therefore, 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.

[0098] Meanwhile, the plurality of light-emitting circuits (130-1 to 130-N) may control the on period (or light-emitting period) of the light-emitting elements (120-1 to 120-N) by cycle (or frame) using digital data and program signals, thereby enabling grayscale expression of an image. Depending on the digital signal, it may be determined whether the light-emitting current (IEM1 to IEMN) generated in the light-emitting circuits (130-1 to 130-N) is supplied to the light-emitting elements (120-1 to 120-N). For example, the digital data may include 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 current (IEM1 to IEMN) generated in the light emitting circuit (130-1 to 130-N) is supplied to the light emitting element (120-1 to 120-N), so that the light emitting element (120-1 to 120-N) can emit light. For example, when the digital data is “0”, the light emitting current (IEM1 to IEMN) generated in the light emitting circuit (130-1 to 130-N) is not supplied to the light emitting element (120-1 to 120-N), so that the light emitting element (120-1 to 120-N) does not emit light.

[0099] The program signal is a control signal for writing input data and may include grayscale information, etc. According to the grayscale information included in the program signal, the width of the on-period (or light-emitting period) is determined differently, so that images having different grayscales or brightness can be displayed. For example, an image having a higher grayscale can be displayed as the on-period increases. For example, since the corresponding light-emitting elements (120-1 to 120-N) emit light in different on-periods on a frame-by-frame basis for the same subpixel, images having different grayscales on a frame-by-frame basis can be displayed.

[0100] Accordingly, whether or not the light-emitting elements (120-1 to 120-N) emit light is determined based on digital data, and by controlling the on period (light-emitting period) of the light-emitting elements (120-1 to 120-N) based on a program signal, an image having a desired gradation or brightness can be displayed.

[0101] In the drawing, the G node may be a node between the gate of the transistor of the reference current generation circuit (110) constituting the current mirror circuit and the gate of each transistor of the plurality of light-emitting circuits (130-1 to 130-N).

[0102] A predetermined voltage can be generated at the G node through the transistor of the reference current generation circuit (110) by the reference current (IREF) generated in the reference current generation circuit (110). A plurality of light-emitting currents (IEM1 to IEMN) can be generated in the transistors of the plurality of light-emitting elements (120-1 to 120-N) by the predetermined voltage. In this case, as described above, since the aspect ratio of the transistors of the light-emitting elements (120-1 to 120-N) is designed to be the same as or different from the aspect ratio of the transistors of the reference current generation circuit (110), the same or different light-emitting currents (IEM1 to IEMN) can be generated in the transistors of each of the plurality of light-emitting elements (120-1 to 120-N) based on the voltage on the G node.

[0103] Meanwhile, in the embodiment, a plurality of subpixels (SP-1 to SP-N) can be driven simultaneously. That is, a plurality of subpixels (SP-1 to SP-N) are driven simultaneously within one frame, and the on period of the light-emitting elements (120-1 to 120-N) of each of the plurality of subpixels (SP-1 to SP-N) is controlled so that images of different grayscale levels can be displayed on each of the subpixels (SP-1 to SP-N).

[0104] 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).

[0105] As a first example, a reference current generation circuit (110) connected to a third power line (143) and a second power line (142) can generate a reference current (IREF).

[0106] As a second example, a plurality of light-emitting circuits (130-1 to 130-N) connected to a first power line (141) and a second power line (142) can generate a plurality of light-emitting currents (IEM1 to IEMN).

[0107] As a third example, the reference current (IREF) generated in the reference current generation circuit (110) can be output through the measurement line (145).

[0108] As a fourth example, a plurality of light emitting currents (IEM1 to IEMN) generated from a plurality of light emitting circuits (130-1 to 130-N) can be individually or simultaneously output through the measurement line (145).

[0109] As a fifth example, non-luminous current generated in multiple light-emitting circuits (130-1 to 130-N) can be output through a measurement line (145).

[0110] Meanwhile, in the embodiment, the reference current (IREF), the luminous current (IEM1 to IEMN) and / or the non-luminous current output through the measurement line (145) can be measured and used to control the reference current generation circuit (110) and / or the plurality of luminous circuits (130-1 to 130-N).

[0111] To this end, the display device according to the first embodiment may include a current measurement circuit (170), a current control circuit (180), etc.

[0112] The current measuring circuit (170) can be electrically connected to the reference current generating circuit (110) and the plurality of light emitting circuits (130-1 to 130-N) through the measuring circuit (145). The current measuring circuit (170) measures the reference current (IREF), the light emitting current (IEM1 to IEMN) and / or the non-light emitting current through the measuring circuit (145), and outputs the measurement results (I of mathematical expressions 3 to 6). M1 Inland I M4 ) can be obtained.

[0113] The current control circuit (180) can generate control signals (such as E11, C21 in 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 current (IEM1 to IEMN) and / or the non-light-emitting current measured by the current measurement circuit (170). As will be described later, in response to one control signal (E11) of these control signals (such as E11, C21), the plurality of selection switches (156-1) of the voltage generation circuit (150) (150 in FIG. 3) can be selectively turned on, so that the reference voltage (VREF) can be adjusted. In addition, a plurality of selection switches (112-1) of the reference current generation circuit (110) can be selectively turned on in response to another control signal (C21) among the control signals (E11, C21, etc.), so that the reference current (IREF) can be adjusted.

[0114] For example, when a voltage generation circuit (150), a current generation circuit (110), and a 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.

[0115] The current measurement circuit (170) can measure the reference current (IREF), the luminous current (IEM1 to IEMN) and / or the non-luminous current. For example, the current measurement circuit (170) can measure the reference current (IREF), the luminous current (IEM1 to IEMN) and / or the non-luminous current through the measurement circuit (150) during the production process of each first IC or during the display operation of the display device according to the first embodiment.

[0116] The current control circuit (180) can obtain a difference in the reference current (IREF) or the luminescence current due to a difference in the characteristics of a plurality of first ICs that may occur during the production of the plurality of first ICs, or a difference in the reference current (IREF) or the luminescence current that may occur under a driving environment or specific conditions, based on the measured reference current (IREF), luminescence current (IEM1 to IEMN) and / or non-luminescence current.

[0117] In addition, the current control circuit (180) can control the voltage generation circuit (150) to adjust the reference voltage (VREF) or the reference current generation circuit (110) to adjust the reference current (IREF) based on control signals (E11, C21, etc.) including compensation information according to the difference. Accordingly, the uniformity of currents between the plurality of first ICs, for example, the reference current (IREF) or the light emission current, can be secured, thereby improving the image quality.

[0118]

[0119] [Example 2]

[0120] 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 configuration 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).

[0121] As illustrated in FIG. 3, the voltage generation circuit (150) can provide a reference voltage (VREF) to the reference current generation circuit (110). The voltage generation circuit (150) can be connected to the reference current generation circuit (110) via the X node. Therefore, the voltage generation circuit (150) can output the reference voltage (VREF) to the reference current generation circuit (110) via the X node. The reference current generation circuit (110) can generate a reference current (IREF) based on the reference voltage (VREF).

[0122] The voltage generation circuit (150) may include a first transistor (T31), a reference voltage control circuit, a control switch (151-1, 151-2), etc.

[0123] The first transistor (T31) may be diode-connected. That is, the gate and drain of the first transistor may be electrically connected. The first transistor (T31) may include a PMOS transistor, but is not limited thereto.

[0124] The reference voltage regulation circuit is connected to the first transistor (T31) and can regulate the reference voltage (VREF). The reference voltage regulation circuit may include a second transistor (T32-1) and a selection switch (156-1). The second transistor (T32-1) may be diode-connected and may include a PMOS transistor.

[0125] Although the drawing shows one second transistor (T32-1) and one selection switch (156-1), multiple second transistors may be connected in parallel with each other, and multiple selection switches may be connected in series with each of the multiple second transistors. Hereinafter, T32-1 may be used as a drawing symbol indicating multiple second transistors, and 156-1 may be used as a drawing symbol indicating multiple selection switches.

[0126] The gates of the plurality of second transistors (T32-1) may be commonly connected. In this case, the plurality of second transistors (T32-1) may be turned on / off in response to a control signal (E11). By selectively turning on the plurality of second transistors (T32-1), at least one 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 transistor (T32-1) and the first transistor (T31).

[0127] A plurality of second transistors (T32-1) of the reference voltage control circuit and a plurality of second transistors (T22-1) of the reference current control circuit (115) can form a current mirror circuit.

[0128] Although the drawing shows one second transistor (T22-1) and one selection switch (112-1), multiple second transistors may be connected in parallel with each other, and multiple selection switches may be connected in series with each of the multiple second transistors. Hereinafter, T22-1 may be used as a drawing symbol indicating multiple second transistors, and 112-1 may be used as a drawing symbol indicating multiple selection switches.

[0129] 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 control circuit (115) can be commonly connected to the X node.

[0130] In this case, the reference voltage (VREF) controlled by at least one second transistor selected from among the plurality of second transistors (T32-1) and the first transistor (T31) can be output to the X node. At least one constant current can be generated from at least one second transistor (T22-1) selected from among the plurality of second transistors (T22-1). When the reference voltage (VREF) is controlled differently, at least one constant current can also be changed differently.

[0131] 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 include a third transistor (T33-1). The third transistor (T33-1) may include 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) between the third power line (143) and the plurality of second transistors (T32-1), respectively.

[0132] 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 the threshold voltage of the second transistor (T32-1), but this is not limited thereto.

[0133] A plurality of third transistors (T33-1) are each connected in series to a plurality of second transistors (T32-1), so that in response to selective turning on of the plurality of third transistors (T33-1), a reference voltage (VREF) determined by at least one second-1 transistor selected from among the plurality of second transistors (T32-1) and the first transistor (T31) can be output through the G node. The reference voltage (VREF) can be generated by voltage-dividing the diode voltage of the first transistor (T31) and the diode voltage of the selected at least one second transistor (T32-1), but this is not limited thereto.

[0134] Meanwhile, the control switches (151-1, 151-2) can control the on / off of the display operation. The control switches (151-1, 151-2) can control the operation of the voltage generation circuit (150), the reference current generation circuit (110), and the operation of each of the light-emitting circuits (130-1 to 130-N).

[0135] The control switch (151-1, 151-2) may include a first control transistor (T41) and a second control transistor (T42).

[0136] A first control transistor (T41) may be connected between a first transistor (T31) and a fourth power line (144), and a second control transistor (T42) may be connected between a third power line (143) and the first transistor (T31). A third power voltage (PVDD) may be supplied to the third power line (143), and a 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.

[0137] The first control transistor (T41) may include an NMOS transistor, and the second control transistor (T42) may include a PMOS transistor. The gate of the first control transistor (T41) and the gate of the second control transistor (T42) may be commonly connected.

[0138] For example, in response to a high-level control signal (EC), the first control transistor (T41) may be turned on and the second control transistor (T42) may be turned off, thereby performing a display operation. In this case, a reference voltage (VREF) may be output from the voltage generation circuit (150) to the X node, the reference current generation circuit (110) may generate a reference current (IREF) based on the reference voltage (VREF), and the first light-emitting circuit (130-1) may generate a first light-emitting current (IEM1) based on the reference current (IREF). Accordingly, the first light-emitting element (120-1) may emit light by the first light-emitting current (IEM1), so that an image may be displayed.

[0139] For example, in response to a low-level control signal (EC), the first control transistor (T41) may be turned off and the second control transistor (T42) may be turned on, thereby stopping the display operation. In this case, since the voltage generation circuit (150) does not operate, the reference voltage (VREF) is not output to the X node. Accordingly, the reference current (IREF) of the reference current generation circuit (110) and the first emission current (IEM1) of the first emission circuit (130-1) are not generated, so that the image is not displayed.

[0140] Meanwhile, the reference current generation circuit (110) may be connected to the first subpixel (SP-1). The reference current (IREF) generated or controlled by the reference current generation circuit (110) is copied to the first subpixel (SP-1), so that the first light-emitting current (IEM1) is 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).

[0141] In an embodiment, the reference current generation circuit (110) may include a reference current adjustment circuit (115) that adjusts the reference current (IREF). When the reference current (IREF) is adjusted 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).

[0142] The luminance of the first light-emitting element (120-1) can 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) can increase. For example, the first light-emitting current (IEM1) may decrease due to differences in manufacturing characteristics or environmental differences, thereby lowering the luminance of the first light-emitting element (120-1). In this case, the reference current (IREF) is adjusted to increase in the reference current control circuit (115), thereby increasing the first light-emitting current (IEM1) of the first light-emitting circuit (130-1), thereby increasing the luminance of the first light-emitting element (120-1).

[0143] The reference current control circuit (115) may include a constant current source (111-1) and a selection switch (112-1). Although one constant current source (111-1) and one selection switch (112-1) are illustrated in the drawing, multiple constant current sources may be connected in parallel with each other, and multiple selection switches may be connected in series with each other to multiple constant current sources. Hereinafter, 111-1 may be used as a drawing symbol indicating multiple constant current sources, and 112-1 may be used as a drawing symbol indicating multiple selection switches.

[0144] 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 line (143) and the first transistor (T21).

[0145] A plurality of constant current sources (111-1) and a plurality of selection switches (112-1) may be electrically connected to each other. 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 include a second transistor (T22-1), and the plurality of selection switches (112-1) may each include a third transistor (T23-1). The second transistor (T22-1) and the third transistor (T23-1) may be PMOS transistors, but are not limited thereto.

[0146] For example, a plurality of second transistors (T22-1) may be connected in parallel between the third power line (143) and the first transistor (T21).

[0147] In this case, 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 the reference voltage (VREF) input to the gates. The plurality of constant currents may be the same or different.

[0148] At this time, the generation of multiple constant currents can be determined depending on whether multiple selection switches (112-1) are turned on / off.

[0149] A plurality of selection switches (112-1) may each be connected in series with a plurality of second transistors (T22-1). Each of the plurality of selection switches (112-1) may include a third transistor (T23-1). The third transistor (T23-1) may include a PMOS transistor, but is not limited thereto.

[0150] For example, a plurality of third transistors (T23-1) may be connected in series with a plurality of second transistors (T22-1) between the third power line (143) and the first transistor (T21), respectively. In this case, 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).

[0151] A reference current (IREF) can be generated using at least one constant current selected from among a plurality of constant currents. For example, as the number of selected constant currents increases, the reference current (IREF) can increase. The reference current (IREF) can be used to generate a first light emission current (IEM1) in the first light emission circuit (130-1).

[0152] The plurality of third transistors (T23-1) can 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) can 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) can be turned off.

[0153] The drawing shows four constant current sources (111-1) and four selector switches (112-1), but more constant current sources and selector switches may be provided.

[0154] Meanwhile, the reference current generation circuit (110) may include a first transistor (T21) and a third control switch (113-1, 113-2) connected to the first transistor (T21).

[0155] The first transistor (T21) can be diode-connected. That is, the gate and drain of the first transistor (T21) can be commonly connected. A reference current (IREF) determined by a plurality of constant currents generated from a plurality of constant current sources (111-1) can flow through the first transistor (T21).

[0156] The first transistor (T21) of the reference current generation circuit (110) can form a current mirror circuit with the first transistor (T11) of the first light-emitting circuit (130-1). In this case, the gate of the first transistor (T21) of the reference current generation circuit (110) and the gate of the first transistor (T11) of the first light-emitting circuit (130-1) can be commonly connected to the G node.

[0157] The third control switch (113-1, 113-2) is connected to the first transistor (T21) and can 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).

[0158] The third control switch may include a third-first control switch (113-1) and a third-second control switch (113-2). The third-first control switch (113-1) 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 control circuit (115) and the first transistor (T21).

[0159] The 3-1 control switch (113-1) may include a sixth transistor (T24), and the 3-2 control switch (113-2) may include a seventh transistor (T25). The sixth transistor (T24) may include an NMOS transistor, and the seventh transistor (T25) may include a PMOS transistor.

[0160] The 3-1 control switch (113-1) and the 3-2 control switch (113-2) can be turned on or off simultaneously by the control signals (D1, D2). For example, when the control signal (D1) has a high level and the control signal (D2) has a low level, both the 3-1 control switch (113-1) and the 3-2 control switch (113-2) can be turned on. For example, when the control signal (D1) has a low level and the control signal (D2) has a high level, both the 3-1 control switch (113-1) and the 3-2 control switch (113-2) can be turned off.

[0161] When the 3-1 control switch (113-1) and the 3-2 control switch (113-2) are in the open state by the control signals (D1, D2), the reference current (IREF) does not flow to the first transistor (T21), which may mean that the reference current (IREF) is turned off. When the 3-1 control switch (113-1) and the 3-2 control switch (113-2) are in the closed state by the control signals (D1, D2), the reference current (IREF) flows to the first transistor (T21), which may mean that the reference current (IREF) is turned on. The time period during which the reference current (IREF) flows to the first transistor (T21) may be defined as an on period. The time period during which the reference current (IREF) does not flow to the first transistor (T21) may be defined as an off period.

[0162] For example, it can be divided into an on period and an off period by period. A period can be, for example, one frame, but is not limited thereto. During the on period, since the 3-1 control switch (113-1) and the 3-2 control switch (113-2) are in a closed state, the reference current (IREF) can flow to the first transistor (T21). During the off period, since the 3-1 control switch (113-1) and the 3-2 control switch (113-2) are in an open state, the reference current (IREF) may not flow to the first transistor (T21).

[0163] Meanwhile, the reference current generation circuit (110) may include a first control switch (116), a second control switch (117), and a third control switch (113-1, 113-2).

[0164] The first control switch (116) can be connected between the first transistor (T21) and the second power line (142), and the second control switch (117) can be connected between the first transistor (T21) and the measurement line (145).

[0165] The first control switch (116) may include a fourth transistor (T26), and the second control switch (117) may include a fifth transistor (T27). The fourth transistor (T26) and the fifth transistor (T27) may include NMOS transistors, but are not limited thereto.

[0166] As an example, the first control switch (116) may be turned on and the second control switch (117) may be turned off. In this case, the first transistor (T21) may be connected to the second power line (142), and when the third control switch (113-1, 113-2) is turned on, a reference current (IREF) determined based on at least one constant current generated in the reference current control circuit (115) may be generated.

[0167] As another example, the first control switch (116) may be turned off and the second control switch (117) may be turned on. In this case, the first transistor (T21) may be connected to the measurement line (145), so that when the third control switch (113-1, 113-2) is turned on, the generated reference current (IREF) may be output through the measurement line (145).

[0168] Meanwhile, the first subpixel (SP-1) may include a first light-emitting circuit (130-1) and a first light-emitting element (120-1). The first light-emitting element (120-1) may also be included in the first light-emitting circuit (130-1).

[0169] The first light-emitting circuit (130-1) can drive the first light-emitting element (120-1) to emit light. To this end, the first light-emitting circuit (130-1) generates a first light-emitting current (IEM1), and the first light-emitting element (120-1) can emit light by the generated first light-emitting current (IEM1). The first light-emitting current (IEM1) can be a constant current.

[0170] The first luminescence current (IEM1) can be generated in response to the reference current (IREF) adjusted in the reference current generation circuit (110). That is, when the reference current (IREF) increases, the first luminescence current (IEM1) can also increase.

[0171] The first light-emitting circuit (130-1) may include a first transistor (T11), a fifth control switch (SW11, SW12-1, SW12-2), etc.

[0172] 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, the anode electrode of the first light-emitting element (120-1) may be electrically connected to the first power line (141), the cathode electrode of the first light-emitting element (120-1) may be electrically connected to the drain of the first transistor (T11), and the source of the first transistor (T11) may be electrically connected to the second power line (142).

[0173] The first transistor (T11) can generate a first light emission current (IEM1). The first light emission current (IEM1) can be generated based on a reference current (IREF) generated by a reference current generation circuit (110). The first transistor (T11) can generate a first light emission current (IEM1) corresponding to the reference current (IREF) generated by the reference current generation circuit (110). The first transistor (T11) can generate a first light emission current (IEM1) that is a copy of the reference current (IREF). When the first light emission current (IEM1) is generated by the first transistor (T11), the first light-emitting element (120-1) can emit light by the first light emission current (IEM1).

[0174] A current mirror circuit can 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, a first light-emitting current (IEM1) can 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) can be equal to or greater than the reference current (IREF).

[0175] 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.

[0176] The first transistor (T21) of the reference current generation circuit (110) is diode-connected, and the gate of the first transistor (T21) of the reference current generation circuit (110) and the gate of the first transistor (T11) of the first light-emitting circuit (130-1) can be commonly connected to the G node. In addition, the source of the first transistor (T21) of the reference current generation circuit (110) and the source of the first transistor (T11) of the first light-emitting circuit (130-1) can be commonly connected to the second power line (142).

[0177] In this case, the reference current (IREF) flowing in the reference current generation circuit (110) can be expressed by mathematical expression 1, and the first light emission current (IEM1) flowing in the first light emission circuit (130-1) can be expressed by mathematical expression 2.

[0178] [Mathematical Formula 1]

[0179]

[0180] [Equation 2]

[0181]

[0182] From mathematical expression 1, the voltage of node G (V G) can be produced. 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 the voltage of the G node.

[0183] The first transistor (T11) of the first light-emitting circuit (130-1) may be a conversion element that converts the voltage of the G node into a first light-emitting current (IEM1).

[0184] From mathematical expressions 1 and 2, the process constant (μ, C) in the first transistor (T21) of the reference current generation circuit (110) and the first transistor (T11) of the first light-emitting circuit (130-1) ox ) and aspect ratio (W D / L D , W E / L E ) are the same, the reference current (IREF) and the first emission current (IEM1) may be the same. In this case, the reference current (IREF) may be copied as is and generated as the first emission current (IEM1) in the first emission circuit (130-1).

[0185] In contrast, the process constant (μ, C) in the first transistor (T21) of the reference current generation circuit (110) and the first transistor (T11) of the first light-emitting circuit (130-1) ox ) are the same, but the aspect ratio (W D / L D , W E / L E ) are different, the reference current (IREF) and the first emission current (IEM1) may be different. For example, the aspect ratio (W) of the first transistor (T11) of the first emission circuit (130-1) E / L E ) is the aspect ratio (W) of the first transistor (T21) of the reference current generation circuit (110). D / L D ), the first emission current (IEM1) may be greater than the reference current (IREF). For convenience, the aspect ratio (W) of the first transistor (T21) of the reference current generation circuit (110) D / L D ) is named as the first aspect ratio, and the aspect ratio (W) of the first transistor (T11) of the first light-emitting circuit (130-1) E / L E ) can be named the second aspect ratio.

[0186] Therefore, the first aspect ratio (W D / L D ) is designed to be small, so that a small reference current (IREF) can be generated in the reference current generation circuit (110). Accordingly, the burden of generating the reference current (IREF) is reduced, the size of the reference current generation circuit (110) is reduced, and power consumption can be reduced.

[0187] Also, the second aspect ratio (W E / L E ) is designed to be large, so that a large first light-emitting current (IEM1) can 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 brightness can be implemented.

[0188] Meanwhile, the fifth control switch (SW11, SW12-1, SW12-2) of the first light-emitting circuit (130-1) is connected to the first transistor (T11) and can control on / off of the first light-emitting current (IEM1). The fifth control switch (SW11, SW12-1, SW12-2) may include a 5-1 control switch (SW11), a 5-2 control switch (SW12-1), and a 5-3 control switch (SW12-2). The 5-1 control switch (SW11) may include an NMOS transistor, and the 5-2 control switch (SW12-1) and the 5-3 control switch (SW12-2) may include PMOS transistors, but are not limited thereto.

[0189] The 5-1 control switch (SW11) may be connected between the first transistor (T11) and the second power line (142), the 5-2 control switch (SW12-1) may be connected between the first light-emitting element (120-1) and the first transistor (T11), and the 5-3 control switch (SW12-2) may be connected to the third power line (143). The gate of the 5-2 control switch (SW12-1) and the gate of the 5-3 control switch (SW12-2) may be commonly connected.

[0190] The 5-1 control switch (SW11) may include a 6th transistor (T12-1), the 5-2 control switch (SW12-1) may include a 7th transistor (T13-1), and the 5-3 control switch (SW12-2) may include an 8th transistor (T13-2).

[0191] The sixth transistor (T12-1) may include an NMOS transistor, and the seventh transistor (T13-1) and the eighth transistor (T13-2) may be PMOS transistors.

[0192] The 5-1 control switch (SW11), the 5-2 control switch (SW12-1), and the 5-3 control switch (SW12-2) can be turned on or off simultaneously by control signals (C11, C12). The 5-2 control switch (SW12-1) and the 5-3 control switch (SW12-2) can be turned on / off simultaneously by control signal (C12).

[0193] When the 5-1st control switch (SW11) and the 5-2nd control switch (SW12-1) are in an open state by the control signals (C11, C12), the first light emission current (IEM1) does not flow to the first transistor (T11), which may mean that the first light emission current (IEM1) is turned off. When the 5-1st control switch (SW11) and the 5-2nd control switch (SW12-1) are in a closed state by the control signals (C11, C12), the first light emission current (IEM1) flows to the first transistor (T11), which may mean that the first light emission current (IEM1) is turned on. The time period during which the first light emission current (IEM1) flows to the first transistor (T11) may be defined as an on period. The time period during which the first light emission current (IEM1) does not flow to the first transistor (T11) may be defined as an off period.

[0194] For example, it can be divided into an on section (or light-emitting section) and an off section (non-light-emitting section) by cycle. The cycle can be, for example, one frame, but is not limited thereto. During the on section, the 5-1st control switch (SW11) and the 5-2nd control switch (SW12-1) are in a closed state, so that the first light-emitting current (IEM1) flows to the first transistor (T11), so that the first light-emitting element (120-1) can light up. During the off section, the 5-1st control switch (SW11) and the 5-2nd control switch (SW12-1) are in an open state, so that the first light-emitting current (IEM1) does not flow to the first transistor (T11), so that the first light-emitting element (120-1) may not light up.

[0195] For convenience of explanation, the ON period in which the reference current (IREF) flows through the first transistor (T21) of the reference current generation circuit (110) may be named a first ON period, and the ON period in which the first light emission current (IEM1) flows through the first transistor (T11) of the first light emission circuit (130-1) may be named a second ON period.

[0196] When the third control switch (113-1, 113-2) of the reference current generation circuit (110) is in a closed state in response to the control signal (D1, D2), the reference current (IREF) can flow to the first transistor (T21) of the reference current generation circuit (110) during the first on-period. When the fifth control switch (SW11, SW12-1, SW12-2) of the first light-emitting circuit (130-1) is in a closed state in response to the control signal (C11, C12), the first light-emitting current (IEM1) can flow to the first transistor (T11) of the first light-emitting circuit (130-1) during the second on-period.

[0197] The second on-period may be included within the first on-period. The width of the second on-period may be greater than the width of the first on-period. The rising time of the first on-period may be faster than the rising time of the second on-period, and the falling time of the first on-period may be slower than the falling time of the second on-period.

[0198] Meanwhile, the first light-emitting circuit (130-1) may include digital storage. The digital storage may generate control signals (C11, C12) for switching the fifth control switches (SW11, SW12-1, SW12-2) of the first light-emitting circuit (130-1) using digital data and program signals.

[0199] In response to the control signals (C11, C12), the fifth control switch (SW11, SW12-1, SW12-2) can be turned on / off. When the fifth control switch (SW11, SW12-1, SW12-2) is in a closed state during the second on period in response to the control signals (C11, C12), the first light-emitting current (IEM1) is generated in the first transistor (T11), and the first light-emitting element (120-1) can emit light by the generated first light-emitting current (IEM1).

[0200] Since the fifth control switch (SW11, SW12-1, SW12-2) remains closed during the second on period, the first light-emitting element (120-1) can emit light during the second on period.

[0201] The second ON period may be determined by a program signal, but is not limited thereto. The program signal may include grayscale information for determining the second ON period. Accordingly, a control signal (C11, C12) having a second ON period can be generated based on digital data and the program signal. For example, the larger the grayscale, the larger the second ON period. Accordingly, by changing the width of the second ON period, an image having a desired grayscale can be displayed.

[0202] Meanwhile, a control signal (D1, D2) for maintaining the third control switch (113-1, 113-2) of the reference current generation circuit (110) in a closed state during the first on period may be provided from an external source, such as a host, a data processing device, a processor, a controller, etc.

[0203] According to an embodiment, a first light emission current (IEM1), which is a constant current, may be generated in the first transistor (T11) of the first light emission circuit (130-1) in response to the reference current (IREF) generated in the reference current generation circuit (110). At this time, a second on-period is determined or controlled based on digital data and a program signal, and the first light-emitting element (120-1) emits light during the second on-period, thereby allowing images having different grayscales to be displayed. For example, as the second on-period increases, an image having a higher grayscale may be displayed.

[0204] Meanwhile, the first light-emitting circuit (130-1) may include a first control switch (131-1), a second control switch (132-1), a third control switch (133-1), and a fourth control switch (134-1). The first 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.

[0205] The first control switch (131-1) can be connected between the first transistor (T11) and the second power line (142), and the second control switch (132-1) can be connected between the first transistor (T11) and the measurement line (145).

[0206] 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).

[0207] The first control switch (131-1) may include a second transistor (T14), and the second control switch (132-1) may include a third transistor (T15). The third control switch (133-1) may include a fourth transistor (T16), and the fourth control switch (134-1) may include a fifth transistor (T17).

[0208] The second transistor (T14) and the third transistor (T15) may include, but are not limited to, NMOS transistors. The second transistor (T14) may be turned on in response to a high-level first control signal (CSA). The third transistor (T15) may be turned on in response to a high-level second control signal (CSB).

[0209] The fourth transistor (T16) and the fifth transistor (T17) may include PMOS transistors, but are not limited thereto. The fourth transistor (T16) may be turned on in response to a low-level third control signal (CSC). The fifth transistor (T17) may be turned on in response to a low-level fourth control signal (CSD).

[0210] 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) can be turned on or 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) can be turned on simultaneously in response to the first control signal (CSA) of a high level.

[0211] The second control switch (132-1) of the first light-emitting circuit (130-1) and the second control switch (117) of the reference current generation circuit (110) can be turned on or off simultaneously by the second control signal (CSB). When 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 by the second control signal (CSB), the second control switch (132-1) of the first light-emitting circuit (130-1) and the second control switch (117) of the reference current generation circuit (110) can be turned on simultaneously in response to the second control signal (CSB) of a high level.

[0212] As an example, the first control switch (131-1) is turned on and the second control switch (132-1) is turned off, so that the first transistor (T11) is 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 switch (SW11, SW12-1, SW12-2) are turned on and the fourth control switch (134-1) is turned off, a first light emission current (IEM1) may be generated in the first light emission circuit (130-1).

[0213] 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) is connected to the measurement line (145) but may be electrically disconnected from the second power line (142). In this case, the first light emission current (IEM1) during light emission or the non-light emission current during non-light emission may be output through the measurement line (145). The first light emission current (IEM1) may be a current for emitting light from the first light emitting element (120-1). The non-light emission current may be a current generated in the first light emitting circuit (120-1) between the third power line (143) and the second power line (142). The non-light emission current may be different from the first light emission current (IEM1).

[0214] For example, when the third control switch (133-1) and the fifth control switch (SW11, SW12-1, SW12-2) are turned on and the fourth control switch (134-1) is turned off, the first light emission current (IEM1) generated in the first transistor (T11) of the first light emission circuit (130-1) between the first power line and the measurement line (145) can be output through the measurement line (145) to cause the first light emission element (120-1) to emit light. For example, when the third control switch (133-1) is turned off and the fourth control switch (134-1) and the fifth control switches (SW11, SW12-1, SW12-2) are turned on, the non-luminous 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) can be output through the measurement line (145).

[0215] Meanwhile, various currents can 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 can be measured by the current measuring circuit (170) (170 in FIG. 2).

[0216] As a first example, the reference current (IREF) generated in the reference current generation circuit (110) as in mathematical expression 3 is measured as a result (I M1 ) can be measured.

[0217] [Equation 3]

[0218] I M1 = IREF

[0219] As a second example, the reference current (IREF) and the specific luminous current are measured as a result (I) while a specific luminous element is emitting light, as in Equation 4. M2 ) can be measured.

[0220] [Equation 4]

[0221] IM2 = IREF + IEM#_ON

[0222] IEM#_ ON can indicate a light emitting current generated in a specific light emitting circuit that is to be measured by emitting a specific light emitting element among a plurality of light emitting circuits (130-1 to 130-N in FIG. 2).

[0223] For example, the measurement results (I M2 ) can be the sum of the reference current (IREF) and a specific luminous current, but is not limited thereto.

[0224] As a third example, the reference current (IREF) and the specific non-emitting current are measured as a result (I) while a specific light-emitting element is not emitting, as in Equation 5. M3 ) can be measured.

[0225] [Equation 5]

[0226] I M3 = IREF + IEM#_OFF

[0227] IEM#_OFF can represent a non-luminous current generated in a specific light-emitting circuit to be measured without a specific light-emitting element emitting light among multiple light-emitting circuits (130-1 to 130-N in FIG. 2).

[0228] For example, the measurement results (I M3 ) can be the sum of the reference current (IREF) and a specific non-luminous current, but is not limited thereto.

[0229] For example, the measurement results (I) shown in each of mathematical expressions 3 to 5 M1 , I M2 , I M3) is used to control the reference voltage control circuit of the voltage generation circuit (150) and / or the reference current control circuit (115) of the reference current generation circuit (110), thereby controlling the light emission current (IEM1 to IEMN) of each light emission circuit (130-1 to 13-N). Accordingly, the uniformity of current between a plurality of ICs (first IC) can be secured, thereby improving the image quality.

[0230] The measurement results shown in mathematical expressions 3 to 5 (I M1 , I M2 , I M3 ) is described in detail with reference to FIGS. 5 to 7.

[0231] According to the embodiment, since the first light-emitting circuit (130-1) is not equipped with a capacitor, it is not subject to area restrictions, and thus the aperture ratio can be increased, thereby improving the brightness.

[0232] According to an embodiment, a display driving device including a converter that converts digital data into analog data is not required, so that the circuit structure can be simplified, the occupied area can be reduced, and the cost can be reduced.

[0233] According to the embodiment, the reference current (IREF) is adjusted differently from each other, so that accurate brightness control is possible at any time.

[0234] According to an embodiment, brightness control between display screens is easily achieved by switching a plurality of selection switches (112-1) provided in a reference current control circuit (115).

[0235] According to an embodiment, a plurality of different reference voltages (VREF) may be provided in a voltage generation circuit (150), and a plurality of different reference currents (IREF) may be generated based on each of the plurality of reference voltages (VREF) in a reference current generation circuit (110). In this case, a first light-emitting circuit (130-1) may generate a first light-emitting current (IEM1) that is different from each other based on the plurality of different reference currents (IREF).

[0236] For example, if three selection switches (156-1) are provided in the voltage generation circuit (150), (2 3 -1) = Seven different reference voltages (VREF) can be provided. For example, if four selection switches (112-1) are provided in the reference current control circuit (115) of the reference current generation circuit (110), (2 4 -1)=15 different reference currents (IREF) can be generated. In this case, each of the first light-emitting circuits (130-1) can generate (7*15)=105 different first light-emitting currents (IEM1).

[0237] Accordingly, transistors (T32-1, T33-1, T22-1, T23-1) are provided to control the reference voltage (VREF) and / or the reference current (IREF) in each of the voltage generation circuit (150) and / or the reference current generation circuit (110), so that the desired brightness can be accurately obtained through a number of different first light-emitting currents (IEM1), and thus the image quality can be dramatically improved.

[0238] According to an embodiment, a measurement line (145) is connected to a reference current generation circuit (110) and a plurality of light-emitting circuits (130-1 to 130-N), so that a reference current generated by the reference current generation circuit (110) or a plurality of light-emitting currents (IEM1 to IEMN) or non-light-emitting currents generated by the plurality of light-emitting circuits (130-1 to 130-N) can be measured. Using the current measured in this way, the voltage generation circuit (150) or the reference current generation circuit (110) is controlled, so that uniformity of light-emitting current between displays or between blocks, i.e., uniformity of brightness, can be secured. Here, a block is a circuit configuration unit illustrated in FIG. 2, and a plurality of blocks can be provided on a display panel.

[0239] [Glow Mode]

[0240] FIG. 4 illustrates a display device according to a second embodiment operating in a luminescent mode.

[0241] As shown in Fig. 4, display operation is 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 can be operated.

[0242] Specifically, in response to a high-level control signal (EC), the control switch (151-1) is turned on and the control switch (151-2) is turned off, so that the voltage generation circuit (150) can be operated. In response to the plurality of selection switches (156-1) of the reference voltage adjustment circuit being turned on / off, the threshold voltage of at least one selected second transistor (T32-1) and the reference voltage (VREF) adjusted by the first transistor (T31) can be output.

[0243] Meanwhile, in order to operate in the luminous mode, the first control switch (116) and the third control switches (113-1, 113-2) of the reference current generation circuit (110) may be turned on and the second control switch (117) may be turned off. In this case, 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 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).

[0244] 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 switch (SW11, SW12-1, 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 case, 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 in 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) can emit light by the first light-emitting current (IEM1).

[0245] Although not shown, the first control switch, the third control switch, and the fifth control switch (SW11, SW12-1, SW12-2) of each of the second light-emitting circuits (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 emit light by the second light-emitting current to the Nth light-emitting current generated in each of the second light-emitting circuits (130-2) to the Nth light-emitting circuit (130-N).

[0246] [Reference current measurement mode]

[0247] FIG. 5 illustrates a display device according to a second embodiment operating in a reference current measurement mode.

[0248] As illustrated in Fig. 5, a display operation is 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) can be operated. Accordingly, the reference voltage (VREF) adjusted in the voltage generation circuit (150) is output through the X node, the reference current generation circuit (110) generates an adjusted reference current (IREF) using at least one constant current based on the reference voltage (VREF), and the first light-emitting circuit (130-1) can generate a first light-emitting current (IEM1) corresponding to the reference current (IREF) to emit light from the first light-emitting element (120-1).

[0249] Meanwhile, in order 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, 113-2) may be turned on. In this case, 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) (170 in FIG. 2) may obtain the reference current (IREF) as a measurement result through the measurement line (145), as shown in mathematical expression 3.

[0250] In addition, the fifth control switch (SW11, SW12-1, SW12-2) in the first light-emitting circuit (130-1) may be turned off. In this case, the first light-emitting element (120-1) or the third power line (143) is electrically disconnected from the second power line (142) or the measurement line (145), so that the first light-emitting current or non-light-emitting current is 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.

[0251] Although not shown, the fifth control switches (SW11, SW12-1, SW12-2) of each of the second light-emitting circuits (130-2 in FIG. 2) to the Nth light-emitting circuit (130-N) can 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 circuits (130-2) to the Nth light-emitting circuit (130-N).

[0252] [Luminous current measurement mode]

[0253] FIG. 6 illustrates a display device according to a second embodiment operating in a luminous current measurement mode.

[0254] As illustrated in Fig. 6, a display operation is 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) can be operated. Accordingly, the reference voltage (VREF) adjusted in the voltage generation circuit (150) is output through the X node, the reference current generation circuit (110) generates an adjusted reference current (IREF) using at least one constant current based on the reference voltage (VREF), and the first light-emitting circuit (130-1) can generate a first light-emitting current (IEM1) corresponding to the reference current (IREF) to emit light from the first light-emitting element (120-1).

[0255] Meanwhile, in order to operate in the luminescence 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, 113-2) may be turned on. In this case, 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).

[0256] 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, SW12-2) may be turned on. The first light-emitting circuit (130-1) may be a light-emitting circuit to be measured. In this case, 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).

[0257] The remaining light-emitting circuits that are not the measurement target, i.e., the fifth control switches (SW11, SW12-1, SW12-2) of each of the second light-emitting circuit to the Nth light-emitting circuit, can 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 circuits (130-2) to the Nth light-emitting circuit (130-N).

[0258] Accordingly, the reference current (IREF) generated (or adjusted) in the reference current generation circuit (110) and the first light emission current (IEM1) generated (or adjusted) in the first light emission circuit (130-1) can be output through the measurement line (145). The current measurement circuit (170) (170 in FIG. 2) can obtain the sum of the reference current (IREF) and the first light emission current (IEM1) as a measurement result through the measurement line (145), as shown in mathematical expression 4. In this case, the first light emission current (IEM1) generated in the first light emission circuit (130-1) can be measured by subtracting the measurement result shown in mathematical expression 3 from the measurement result shown in mathematical expression 4. This operation can be performed in the current measurement circuit (170) (170 in FIG. 2) or the current control circuit (180), but is not limited thereto.

[0259] [Non-luminescent current measurement mode]

[0260] FIG. 7 illustrates a display device according to a second embodiment operating in a non-luminous current measurement mode.

[0261] As illustrated in Fig. 7, a display operation is 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) can be operated. Accordingly, the reference voltage (VREF) adjusted in the voltage generation circuit (150) is output through the X node, the reference current generation circuit (110) generates an adjusted reference current (IREF) using at least one constant current based on the reference voltage (VREF), and the first light-emitting circuit (130-1) can generate a first light-emitting current (IEM1) corresponding to the reference current (IREF) to emit light from the first light-emitting element (120-1).

[0262] Meanwhile, in order to operate in a non-luminescent 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, 113-2) may be turned on. In this case, 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).

[0263] 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, SW12-2) may be turned on. The first light-emitting circuit (130-1) may be a light-emitting circuit to be measured. In this case, 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-luminous 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, the third control switch (133-1) is turned off, so the first light-emitting element (120-1) does not emit light.

[0264] The remaining light-emitting circuits that are not the measurement target, i.e., the fifth control switches (SW11, SW12-1, SW12-2) of each of the second light-emitting circuit to the Nth light-emitting circuit, can be turned off. Accordingly, the second light-emitting current to the Nth light-emitting current or the non-light-emitting current (INEM) are not generated or output through the measurement line (145) in each of the second light-emitting circuits (130-2) to the Nth light-emitting circuit (130-N).

[0265] Accordingly, the reference current (IREF) generated (or adjusted) in the reference current generation circuit (110) and the non-luminous current (INEM) generated (or adjusted) in the first light-emitting circuit (130-1) can be output through the measurement line (145). The current measurement circuit (170) (170 in FIG. 2) can obtain the sum of the reference current (IREF) and the non-luminous current (INEM) as a measurement result through the measurement line (145), as shown in mathematical expression 5. In this case, the non-luminous current (INEM) generated in the first light-emitting circuit (130-1) can be measured by changing the measurement result shown in mathematical expression 5 to the measurement result shown in mathematical expression 3. This operation can be performed in the current measurement circuit (170) (170 in FIG. 2) or the current control circuit (180), but is not limited thereto.

[0266]

[0267] [Example 3]

[0268] Fig. 8 is a block diagram illustrating a display device according to a third embodiment.

[0269] The third embodiment is identical to 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) are independently switched and controlled using individual control signals (CSC-1, CSC-2, CSD-1, CSD-2). In the third embodiment, components having the same circuit structure or function as those of the second embodiment (Fig. 3) are given the same drawing numbers, and detailed descriptions thereof are omitted.

[0270] As illustrated in Fig. 8, the reference current generation circuit (110) may include a first control switch (116), a second control switch (117), a third control switch (113-1, 113-2), etc. The first light-emitting circuit (130-1) may include a first control switch (131-1), a second control switch (132-1), a third control switch (133-1), a fourth control switch (134-1), a fifth control switch (SW11, SW12-1, SW12-2), etc.

[0271] The first control switch (116) and the second control switch (117) of the reference current generation circuit (110) and the first control switch (131-1), the second control switch (132-1), the third control switch (133-1) and the fourth control switch (134-1) of the first light-emitting circuit (130-1) can each be turned on / off independently.

[0272] The first control switch (116) and the second control switch (117) of the reference current generation circuit (110) can be independently turned on / off by control signals (CSE, CSF). The first control switch (116) of the reference current generation circuit (110) can be turned on in response to a high-level control signal (CSE). The second control switch (117) of the reference current generation circuit (110) can be turned on in response to a high-level control signal (CSF).

[0273] The first control switch (131-1), the second control switch (132-1), the third control switch (133-1), and the fourth control switch (134-1) of the first light-emitting circuit (130-1) can be independently turned on / off by control signals (CSA, CSB, CSC, CSD). The first control switch (131-1) of the first light-emitting circuit (130-1) can be turned on in response to a high-level control signal (CSA). The second control switch (132-1) of the first light-emitting circuit (130-1) can be turned on in response to a high-level control signal (CSB). The third control switch (133-1) of the first light-emitting circuit (130-1) can be turned on in response to a high-level control signal (CSC). In response to a high level control signal (CSD), the fourth control switch (134-1) of the first light-emitting circuit (130-1) can be turned on.

[0274] In this way, by using more control signals (CSA, CSB, CSC, CSD, CSE, CSF) compared to the second embodiment (Fig. 3), more diverse current measurements can be made possible.

[0275] As an example, as described above, the luminescent current or non-luminescent current generated in at least one luminescent circuit among a plurality of luminescent circuits (130-1 to 130-N in FIG. 2) is measured as a result (I) of mathematical expression 6. M4 ) can be measured.

[0276] [Equation 6]

[0277] I M4 = IEM#

[0278] IEM# may represent a luminescent current or non-luminescent current generated in at least one luminescent circuit among a plurality of luminescent circuits (130-1 to 130-N).

[0279] For example, the luminous current or non-luminous current generated in one luminous circuit is measured as a result (I M4 ) can be measured.

[0280] For example, the luminous current or non-luminous current generated from two or more luminous circuits is measured as a result (I M4 ) can be measured. In this case, the measurement result (I M4 ) may be the sum of luminescent currents generated from two or more luminescent circuits or the sum of non-luminescent currents generated from two or more luminescent circuits.

[0281] [Reference current measurement mode during light emission]

[0282] FIG. 9 illustrates a display device according to a third embodiment operating in a reference current measurement mode during light emission.

[0283] As illustrated in Fig. 9, a display operation is 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) can be operated. Accordingly, the reference voltage (VREF) adjusted in the voltage generation circuit (150) is output through the X node, the reference current generation circuit (110) generates an adjusted reference current (IREF) using at least one constant current based on the reference voltage (VREF), and the first light-emitting circuit (130-1) can generate a first light-emitting current (IEM1) corresponding to the reference current (IREF) to emit light from the first light-emitting element (120-1).

[0284] Meanwhile, in order to operate in the reference current measurement mode during light emission, the first control switch (116) in the reference current generation circuit (110) may be turned off and the second control switch (117) and the third control switches (113-1, 113-2) may be turned on. In this case, 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) (170 in FIG. 2) may obtain the reference current (IREF) as a measurement result through the measurement line (145), as shown in mathematical expression 3.

[0285] 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 switch (SW11, SW12-1, 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 case, a 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 and the second line to cause the first light-emitting element (120-1) to emit light.

[0286] Although not shown, the first control switch, the third control switch, and the fifth control switch (SW11, SW12-1, SW12-2) of each of the second light-emitting circuits (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 emit light by the second light-emitting current to the Nth light-emitting current generated in each of the second light-emitting circuits (130-2) to the Nth light-emitting circuit (130-N).

[0287] 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) can be measured.

[0288] [Reference current measurement mode when not illuminated]

[0289] FIG. 10 illustrates a display device according to a third embodiment operating in a reference current measurement mode in a non-luminous state.

[0290] As illustrated in Fig. 10, a display operation is 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) can be operated. Accordingly, the reference voltage (VREF) adjusted in the voltage generation circuit (150) is output through the X node, the reference current generation circuit (110) generates an adjusted reference current (IREF) using at least one constant current based on the reference voltage (VREF), and the first light-emitting circuit (130-1) can generate a first light-emitting current (IEM1) corresponding to the reference current (IREF) to emit light from the first light-emitting element (120-1).

[0291] Meanwhile, in order to operate in the reference current measurement mode during light emission, the first control switch (116) in the reference current generation circuit (110) may be turned off and the second control switch (117) and the third control switches (113-1, 113-2) may be turned on. In this case, 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) (170 in FIG. 2) may obtain the reference current (IREF) as a measurement result through the measurement line (145), as shown in mathematical expression 3.

[0292] 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, 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 case, a non-luminous 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.

[0293] Although not shown, the second light emitting circuit (130-2 in FIG. 2) to the Nth light emitting circuit (130-N) may generate the second light emitting current to the Nth light emitting current or may generate a non-light emitting current (INEM).

[0294] 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) can be measured.

[0295] From the description of FIGS. 9 and 10, the reference current (IREF) can be measured regardless of the emission of the first light-emitting element (120-1) by the first light-emitting circuit (130-1). From this, it can be seen that the reference current (IREF) can be measured regardless of the emission section or non-emission section of one cycle (or one frame).

[0296] [Measurement mode of luminescence current during luminescence]

[0297] Fig. 11 illustrates a display device according to a third embodiment operating in a luminescence current measurement mode during luminescence.

[0298] As illustrated in Fig. 11, a display operation is 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) can be operated. Accordingly, the reference voltage (VREF) adjusted in the voltage generation circuit (150) is output through the X node, the reference current generation circuit (110) generates an adjusted reference current (IREF) using at least one constant current based on the reference voltage (VREF), and the first light-emitting circuit (130-1) can generate a first light-emitting current (IEM1) corresponding to the reference current (IREF) to emit light from the first light-emitting element (120-1).

[0299] Meanwhile, in order to operate in the reference current measurement mode at the time of light emission, the first control switch (116) and the third control switches (113-1, 113-2) of the reference current generation circuit (110) may be turned on and the second control switch (117) may be turned off. In this case, the first transistor (T21) of the reference current generation circuit (110) may be electrically connected to the second line but may be disconnected from the measurement power line. 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).

[0300] 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, SW12-2) may be turned on. In this case, 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 and the second line to cause the first light-emitting element (120-1) to emit light may be output through the measurement line (145).

[0301] Although not shown, the first control switch and the fourth control switch of at least one light emitting circuit among the second light emitting circuit (130-2 in FIG. 2) to the Nth light emitting circuit (130-N) are turned off, and the second control switch, the third control switch, and the fifth control switch (SW11, SW12-1, SW12-2) are turned on, so that the light emitting current generated in the corresponding light emitting circuit can be output through the measurement line (145).

[0302] As illustrated in Fig. 11, even if the first light-emitting element (120-1) normally emits light by the first light-emitting circuit (130-1), the first light-emitting current (IEM1) generated in the first light-emitting circuit (130-1) can be measured as a measurement result as shown in mathematical expression 6. At this time, in mathematical expression 6, IEM# can represent the first light-emitting current (IEM1) generated in the first light-emitting circuit (130-1).

[0303] At the same time, two or more luminescent currents generated from two or more luminescent circuits may be measured as a measurement result as shown in mathematical expression 6. In this case, the measurement result may be the sum of two or more luminescent currents.

[0304] [Non-luminescent current measurement mode when not emitting light]

[0305] FIG. 12 illustrates a display device according to a third embodiment operating in a non-luminous current measurement mode when not emitting light.

[0306] As illustrated in Fig. 12, a display operation is 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) can be operated. Accordingly, the reference voltage (VREF) adjusted in the voltage generation circuit (150) is output through the X node, the reference current generation circuit (110) generates an adjusted reference current (IREF) using at least one constant current based on the reference voltage (VREF), and the first light-emitting circuit (130-1) can generate a first light-emitting current (IEM1) corresponding to the reference current (IREF) to emit light from the first light-emitting element (120-1).

[0307] Meanwhile, in order to operate in the reference current measurement mode at the time of light emission, the first control switch (116) and the third control switches (113-1, 113-2) of the reference current generation circuit (110) may be turned on and the second control switch (117) may be turned off. In this case, the first transistor (T21) of the reference current generation circuit (110) may be electrically connected to the second line but may be disconnected from the measurement power line. 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).

[0308] 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, SW12-2) may be turned on. In this case, 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-luminous current (INEM) generated in the first transistor (T11) of the first light-emitting circuit (130-1) between the third power line (143) and the second line may be output through the measurement line (145).

[0309] Although not shown, the first control switch and the fourth control switch of at least one light-emitting circuit among the second light-emitting circuit (130-2 in FIG. 2) to the Nth light-emitting circuit (130-N) are turned off, and the second control switch, the third control switch, and the fifth control switch (SW11, SW12-1, SW12-2) are turned on, so that the non-luminous current (INEM) generated in the corresponding light-emitting circuit can be output through the measurement line (145).

[0310] As illustrated in Fig. 9, even if the first light-emitting element (120-1) does not emit light by the first light-emitting circuit (130-1), the non-emission current (INEM) generated in the first light-emitting circuit (130-1) can be measured as a measurement result as shown in mathematical expression 6. At this time, in mathematical expression 6, IEM# can represent the non-emission current (INEM) generated in the first light-emitting circuit (130-1).

[0311] At the same time, two or more non-luminous currents (INEM) generated from two or more light-emitting circuits may be measured as a measurement result as shown in Equation 6. In this case, the measurement result may be the sum of two or more non-luminous currents (INEM).

[0312] 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) are one block (or module), and the display device or display panel according to the first embodiment may be composed of 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 case, the voltage generation circuit (150) may be commonly connected to the plurality of blocks to provide the reference voltage (VREF) to the reference current generation circuit (110) of each of the plurality of blocks.

[0313] Uniformity of luminous current between displays or blocks, i.e., luminance uniformity, can be secured by using the reference current (IREF), luminous current or non-luminous current (INEM) obtained by the various current measurement operations or methods described above.

[0314] The above detailed description should not be construed as limiting in any respect and should be considered illustrative only. The scope of the embodiments should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalency range of the embodiments are intended to be included within the scope of the embodiments.

Claims

1. In a display device including a plurality of subpixels, A plurality of light-emitting elements provided in the plurality of subpixels and connected to a first power line; A reference current generating circuit connected to the third power line; and A plurality of light-emitting circuits are provided in the plurality of subpixels and are connected to the reference current generation circuit and the plurality of light-emitting elements; The above reference current generation circuit and the plurality of light emitting circuits are commonly connected to a second power line, The above reference current generation circuit and the plurality of light emitting circuits are commonly connected to the measurement line, Display device.

2. In paragraph 1, The above reference current generation circuit is, 1st 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; Display device.

3. In paragraph 2, Each of the above plurality of light-emitting circuits is The first transistor of the above reference current generation circuit and the first transistor constituting the mirror 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; Display device.

4. In paragraph 3, The above reference current generation circuit is, A third control switch connected to the first transistor and configured to turn on / off the reference current; Display device.

5. In paragraph 4, Each of the above plurality of light-emitting circuits is A third control switch between the light emitting element and the first transistor; a fourth control switch between the third power line and the first transistor; and A fifth control switch connected to the first transistor and configured to turn on / off the luminescent current; Display device.

6. In paragraph 5, In the light-emitting mode, the first control switch and the third control switch of the reference current generating circuit are turned on and the second control switch is turned off, the plurality of first control switches, the plurality of third control switches and the plurality of fifth control switches of the plurality of light-emitting circuits are turned on and the plurality of second control switches and the plurality of fourth control switches are turned off. Display device.

7. In paragraph 6, In the reference current measurement mode, the first control switch of the reference current generation circuit is turned off, the second control switch and the third control switch are turned on, and the fifth control switch of each of the plurality of light-emitting circuits is turned off. Display device.

8. In paragraph 6, In the luminescence current measurement mode, the first control switch of the reference current generation circuit is turned off, the second control switch and the third control switch are turned on, the first control switch and the fourth control switch of the luminescence circuit to be measured among the plurality of luminescence circuits are turned off, the second control switch, the third control switch and the fifth control switch are turned on, and the fifth control switches of the remaining luminescence circuits among the plurality of luminescence circuits are turned off. Display device.

9. In paragraph 6, In the non-luminescent current measurement mode, the first control switch of the reference current generation circuit is turned off, the second control switch and the third control switch are turned on, the first control switch and the third control switch of the 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 are turned on, and the fifth control switches of the remaining light emitting circuits among the plurality of light emitting circuits are turned off. Display device.

10. In paragraph 6, In the reference current measurement mode at the time of light emission, the first control switch of the reference current generation circuit is turned off, the second control switch and the third control switch are turned on, and the first control switch, the third control switch and the fifth control switch of at least one light emission circuit among the plurality of light emission circuits are turned on, and the second control switch and the fourth control switch are turned off. Display device.

11. In paragraph 6, In the reference current measurement mode in the non-luminous state, the first control switch of the reference current generation circuit is turned off, the second control switch and the third control switch are turned on, and the first control switch, the fourth control switch and the fifth control switch of at least one light-emitting circuit among the plurality of light-emitting circuits are turned on, and the second control switch and the third control switch are turned off. Display device.

12. In paragraph 6, In the luminescence current measurement mode at the time of luminescence, the first control switch and the third control switch of the reference current generation circuit are turned on and the second control switch is turned off, the first control switch and the fourth control switch of at least one luminescence circuit among the plurality of luminescence circuits are turned off and the second control switch, the third control switch and the fifth control switch are turned on. Display device.

13. In paragraph 6, In the non-luminous current measurement mode in the non-luminous state, the first control switch and the third control switch of the reference current generation circuit are turned on and the second control switch is turned off, and the first control switch and the third control switch of at least one 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 are turned on. Display device.

14. In paragraph 1, A current measuring circuit connected to the above measurement line and measuring at least one of a reference current and a luminous current; and Further comprising a current control circuit that controls at least one of the voltage generation circuit and the reference current generation circuit based on the measured current; Display device.

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