Signal processing device and method of operation thereof

Abstract

To provide an OLED display device to improve the expressiveness of dark areas of an input image.SOLUTION: A signal processing device for an Organic Light Emitting Diode (OLED) display may include: a memory configured to store a reference gray level which is a minimum level for turning on an OLED element provided in a pixel or subpixel; and a processor configured to obtain an input gray level corresponding to an input image signal, if the obtained input gray level is less than the reference gray level, generate a compensation level based on the input gray level and the reference gray level, obtain an output gray level based on the generated compensation level, and transmit an output image signal corresponding to the obtained output gray level to a timing controller.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a signal processing device, and more particularly to a signal processing device for an organic light emitting diode display device that can improve the expressiveness in an extremely low gray scale range. [Related Technology] This application claims priority under Article 4 of the Paris Convention based on Korean Patent Application No. 10-2024-0066962 (filing date: May 23, 2024; DAS: 092B), and the present invention is based on the disclosures in that Korean patent application. For reference, the contents of the specification, claims, and drawings of that Korean patent application are incorporated herein by reference. [Background technology]

[0002] A display device is a device that displays images for viewing by a user. For example, the display device may be a television (TV), a monitor, or a notebook computer that includes a liquid crystal display (LCD) or an organic light emitting diode (OLED) display.

[0003] In an OLED display device, in order to express very dark brightness, it is necessary to reduce the brightness of the light output by the OLED element of the corresponding pixel. However, since the brightness of the light output when the OLED element is turned on is brighter than the minimum brightness required by the industry, there is a problem that dark areas cannot be expressed.

[0004] In addition, the turn-on level required to turn on an OLED device varies from product to product, so the problem can occur in different degrees even within the same product. Summary of the Invention [Problem to be solved by the invention]

[0005] The objective of the present disclosure is to improve the rendition of dark areas of an input image in an OLED display device.

[0006] The objective of the present disclosure is to mitigate deviations in the gray levels at which OLED elements are turned on in products, even if the gray levels at which OLED elements are turned on are different. [Means for solving the problem]

[0007] A signal processing device for an organic light emitting diode (OLED) display according to an embodiment of the present disclosure may include (may include; may constitute; may be constructed; may be configured; may include; may contain; may contain) a memory that stores a reference gray level, which is a minimum level for turning on an OLED element provided in a pixel or subpixel, and a processor that acquires an input gray level corresponding to an input video signal, generates a compensation level based on the input gray level and the reference gray level if the acquired input gray level is lower than the reference gray level, acquires an output gray level based on the generated compensation level, and transmits an output video signal corresponding to the acquired output gray level to a timing controller.

[0008] A method for operating a signal processing device for an organic light emitting diode (OLED) display according to an embodiment of the present disclosure may include storing a reference gray level, which is a minimum level for turning on an OLED element provided in a pixel or a subpixel; acquiring an input gray level corresponding to an input image signal; if the acquired input gray level is lower than the reference gray level, generating a compensation level based on the input gray level and the reference gray level; acquiring an output gray level based on the generated compensation level; and transmitting an output image signal corresponding to the acquired output gray level to a timing controller. [One aspect of the present invention] In one aspect of the present invention, the following invention is proposed. [Claim 1] A signal processing device for an organic light emitting diode (OLED) display, comprising: a memory for storing a reference gray level; and a processor; The reference gray level is a minimum level for turning on an OLED element included in a pixel or subpixel, The processor: Obtaining an input gray level corresponding to an input video signal; If the acquired input gray level is less than the reference gray level, generating a compensation level based on the input gray level and the reference gray level; Obtaining an output gray level based on the generated compensation level; and a signal processing device configured to transmit an output video signal corresponding to the obtained output gray level to a timing controller; [Claim 2] The signal processing device of claim 1 , wherein the processor is further configured to compensate the input gray level with a 0 level or the reference gray level based on the generated compensation level. [Claim 3] The signal processing device of claim 2 , wherein the processor is configured to obtain a difference between the input gray level and the reference gray level as the compensation level. [Claim 4] If the acquired input gray level is less than the reference gray level, increasing the probability of converting the input gray level to the reference gray level as the difference between the input gray level and the reference gray level decreases; and The signal processing device according to claim 3 , configured to reduce the probability of converting the input gray level to the reference gray level as the difference between the input gray level and the reference gray level increases. [Claim 5] If the acquired input gray level is less than the reference gray level, The smaller the difference between the input gray level and the reference gray level, the more frequently the input gray level is converted to the reference gray level; and The signal processing device according to claim 3 , configured to: convert the input gray level to the reference gray level less frequently as the difference between the input gray level and the reference gray level increases. [Claim 6] When the pixel includes one OLED element, the processor: 2. The signal processing device of claim 1, configured to obtain the maximum value among red, green, blue and white data values ​​of the input video signal as the input grey level. [Claim 7] When an OLED element is provided for each of a red subpixel, a green subpixel, a blue subpixel, and a white subpixel that constitute the pixel, the processor 2. The signal processing device of claim 1, configured to obtain red, green, blue, and white data values ​​of the input video signal as the input gray levels, respectively. [Claim 8] 1. An OLED display device, comprising: A signal processing device according to claim 1; OLED panels containing multiple pixels; a data driver for outputting a data signal to the OLED panel; a gate driver that outputs a gate signal to the OLED panel; and a timing controller for transmitting a data driving signal to the data driver and a gate driving signal to the gate driver based on the output video signal. [Claim 9] 1. A method for operating a signal processing device for an organic light emitting diode (OLED) display, comprising: storing a reference gray level, which is a minimum level for turning on an OLED element included in a pixel or subpixel; obtaining an input gray level corresponding to an input video signal; generating a compensation level based on the input gray level and the reference gray level if the acquired input gray level is smaller than the reference gray level; obtaining an output gray level based on the generated compensation level; and transmitting an output video signal corresponding to the obtained output gray level to a timing controller. [Claim 10] 10. The method of claim 9, further comprising: compensating the input gray level with a 0 level or the reference gray level based on the generated compensation level. [Claim 11] 11. The method of claim 10, wherein generating the compensation level comprises obtaining a difference between the input gray level and the reference gray level as the compensation level. [Claim 12] If the acquired input gray level is smaller than the reference gray level, increasing the probability of converting the input gray level to the reference gray level as the difference between the input gray level and the reference gray level decreases; and 12. The method of claim 11, further comprising: when the acquired input gray level is smaller than the reference gray level, decreasing the probability of converting the input gray level to the reference gray level as the difference between the input gray level and the reference gray level increases. [Claim 13] If the acquired input gray level is smaller than the reference gray level, increasing the frequency of converting the input gray level to the reference gray level as the difference between the input gray level and the reference gray level decreases; and The method of claim 11 , further comprising: reducing the frequency of converting the input gray level to the reference gray level as the difference between the input gray level and the reference gray level increases. [Claim 14] 10. The method of claim 9, wherein acquiring the input gray level comprises acquiring, when the pixel is equipped with one OLED element, a maximum value among a red data value, a green data value, a blue data value, and a white data value of the input image signal as the input gray level. [Claim 15] 10. The method of claim 9, wherein the acquiring of the input gray level comprises acquiring a red data value, a green data value, a blue data value, and a white data value of the input video signal as the input gray level, respectively, when an OLED element is provided in each of a red sub-pixel, a green sub-pixel, a blue sub-pixel, and a white sub-pixel constituting the pixel. [Effects of the Invention]

[0009] According to the embodiment of the present disclosure, it is possible to eliminate the dropout phenomenon of the video signal that expresses dark brightness in the OLED display, thereby improving the expressiveness in the extremely low gray scale range that expresses dark brightness.

[0010] The OLED display device according to the embodiment of the present disclosure can intentionally degrade or drop an input image signal even in a section where the input gray level of the input image signal is smaller than the reference gray level, thereby eliminating visual artifacts that occur in discontinuous output sections.

[0011] In addition, even if the reference gray level differs for each OLED display device, the expressiveness of the extremely low gray range is improved based on the reference gray level, so mass production deviations can be alleviated. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a block diagram illustrating a configuration of a display device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram of a remote control device according to one embodiment of the present invention. [Figure 3] 1 shows an example of an actual configuration of a remote control device according to an embodiment of the present invention. [Figure 4] 10 illustrates an example of utilizing a remote control device according to an embodiment of the present invention. [Figure 5] 3 is a diagram illustrating the internal configuration of an organic light emitting diode (OLED) display when the display of FIG. 2 is realized by an OLED display. [Figure 6a] FIG. 6 is a diagram referred to in the description of the OLED display of FIG. 5. [Figure 6b] FIG. 6 is a diagram referred to in the description of the OLED display of FIG. 5. [Figure 7] 1 is a flowchart illustrating a method of operating an OLED display device according to an embodiment of the present disclosure. [Figure 8a] FIG. 1 is a diagram showing an output gray level when the input gray level is smaller than the reference gray level according to the prior art; [Figure 8b] FIG. 10 illustrates an output gray level when the input gray level is less than the reference gray level according to an embodiment of the present disclosure. [Figure 9] FIG. 4 is a diagram illustrating the operation of a signal compensator according to an embodiment of the present disclosure. [Figure 10] 10A to 10C are diagrams illustrating results of improved expressiveness in extremely low gradation regions as a result of application of an embodiment of the present disclosure. [Figure 11] FIG. 1 is a diagram illustrating the configuration of a signal processing device for an OLED display according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. The suffixes "module" and "section" used in the following description are given or mixed with each other for the sake of ease of description, and do not have any meanings or roles that are distinct from each other.

[0014] The display device according to an embodiment of the present invention is an intelligent display device that adds a computer support function to a broadcast receiving function, and may have an interface that is more convenient to use than a handwritten input device, a touch screen, or a spatial remote control, while also enhancing the broadcast receiving function. Furthermore, by supporting wired or wireless Internet functionality, the display device can connect to the Internet and a computer and perform functions such as e-mail, web browsing, banking, and games. A standardized general-purpose OS may be used for such various functions.

[0015] Therefore, the display device described in the present invention can perform various user-friendly functions by freely adding or removing various applications on a general-purpose OS kernel. More specifically, the display device may be, for example, a network TV, an HBB TV, a smart TV, an LED TV, an OLED TV, etc., and may also be applicable to a smartphone in some cases.

[0016] FIG. 1 is a block diagram showing the configuration of a display device according to an embodiment of the present invention.

[0017] Referring to FIG. 1, the display device 100 may include a broadcast receiving unit 130, an external device interface 135, a memory 140, a user input interface 150, a controller 170, a wireless communication interface 173, a display 180, a speaker 185, and a power supply circuit 190.

[0018] The broadcast receiving unit 130 may include a tuner 131 , a demodulator 132 , and a network interface 133 .

[0019] The tuner 131 can select a specific broadcast channel according to a channel selection command, and can receive a broadcast signal for the selected specific broadcast channel.

[0020] The demodulator 132 can separate the received broadcast signal into a video signal, an audio signal, and a data signal related to the broadcast program, and can restore the separated video signal, audio signal, and data signal into a form that can be output.

[0021] The external device interface 135 can receive and communicate to the controller 170 or memory 140 an application or list of applications in a nearby external device.

[0022] The external device interface 135 provides a connection path between the display apparatus 100 and an external device. The external device interface 135 can receive one or more of video and audio output from an external device connected to the display apparatus 100 wirelessly or via a wired connection, and transmit the video and audio to the controller 170. The external device interface 135 may include a plurality of external input terminals. The plurality of external input terminals may include an RGB terminal, one or more HDMI (High Definition Multimedia Interface: registered trademark) terminals, and a component terminal.

[0023] A video signal of an external device input via the external device interface 135 is output via a display 180. An audio signal of an external device input via the external device interface 135 can be output via a speaker 185.

[0024] The external device that can be connected to the external device interface 135 may be any one of a set-top box, a Blu-ray player, a DVD player, a game console, a sound bar, a smartphone, a PC, a USB memory, and a home theater, but these are merely examples.

[0025] The network interface 133 provides an interface for connecting the display device 100 to a wired / wireless network including the Internet network. The network interface 133 can transmit or receive data to or from other users or other electronic devices via the connected network or another network linked to the connected network.

[0026] In addition, some content data stored in the display device 100 can be transmitted to a selected user or a selected electronic device from among other users or other electronic devices pre-registered in the display device 100.

[0027] The network interface 133 can connect to a predetermined web page via the connected network or another network linked to the connected network, i.e., can connect to a predetermined web page via the network and transmit or receive data to or from a corresponding server.

[0028] The network interface 133 can receive content or data provided by a content provider or a network operator. That is, the network interface 133 can receive content and related information such as movies, advertisements, games, VOD, and broadcast signals provided by a content provider or a network operator via a network.

[0029] The network interface 133 can also receive firmware update information and update files provided by a network operator, and can transmit data to the Internet, a content provider, or a network operator.

[0030] The network interface 133 can select and receive a desired application from among applications that are open to the public via a network.

[0031] The memory 140 stores programs for signal processing and control within the controller 170, and can store signal-processed video, audio, or data signals.

[0032] The memory 140 can also temporarily store video, audio, or data signals input from the external device interface 135 or the network interface 133, and can store information about a predetermined image using a channel storage function.

[0033] The memory 140 can store an application or an application list input from the external device interface 135 or the network interface 133 .

[0034] The display device 100 can play content files (moving image files, still image files, music files, document files, application files, etc.) stored in the memory 140 and provide them to the user.

[0035] The user input interface 150 can transmit signals input by the user to the controller 170 or can transmit signals from the controller 170 to the user.

[0036] For example, the user input interface 150 can receive and process control signals such as power on / off, channel selection, screen setting, etc. from the remote control device 200 using various communication methods such as Bluetooth (registered trademark: the same applies below), UWB (Ultra Wideband), ZigBee, RF (Radio Frequency) communication method, or infrared (IR) communication method, or can process control signals from the controller 170 to send them to the remote control device 200.

[0037] In addition, the user input interface 150 can transmit control signals input from local keys (not shown) such as a power key, a channel key, a volume key, and a setting key to the controller 170 .

[0038] The video signal processed by the controller 170 can be input to the display 180 and displayed as an image corresponding to the video signal. In addition, the video signal processed by the controller 170 can be input to an external output device via the external device interface 135.

[0039] The audio signal processed in the controller 170 can be output as audio to a speaker 185. The audio signal processed in the controller 170 can also be input to an external output device via the external device interface 135.

[0040] In addition, the controller 170 can control the overall operation of the display device 100 .

[0041] In addition, the controller 170 can control the display device 100 according to user commands or internal programs input via the user input interface 150, and can connect to a network to download a user-desired application or application list into the display device 100.

[0042] The controller 170 controls the display 180 or speaker 185 to output the channel information selected by the user along with the processed video or audio signal.

[0043] In addition, the controller 170 causes a video signal or audio signal from an external device, such as a camera or video camera, input via the external device interface 135 to be output via the display 180 or speaker 185 in response to an external device video playback command received via the user input interface 150.

[0044] Meanwhile, the controller 170 can control the display 180 to display an image, for example, broadcast image input via the tuner 131, externally input image input via the external device interface 135, image input via the network interface unit, or image stored in the memory 140 can be controlled to be displayed on the display 180. In this case, the image displayed on the display 180 may be a still image or a moving image, and may be a 2D image or a 3D image.

[0045] In addition, the controller 170 may control the playback of content stored in the display device 100, received broadcast content, or externally input content, and the content may be in various forms such as broadcast video, externally input video, audio file, still image, connected web screen, and document file.

[0046] The wireless communication interface 173 can communicate with an external device via wired or wireless communication. The wireless communication interface 173 can perform short-range communication with the external device. For this purpose, the wireless communication interface 173 can be implemented using Bluetooth. TM The display device 100 may support short-range communication using at least one of the following technologies: 1) RFID (Radio Frequency Identification), 2) Infrared Data Association (IrDA), 3) Ultra Wideband (UWB), 4) ZigBee, 5) Near Field Communication (NFC), 6) Wireless Fidelity (Wi-Fi), 7) Wi-Fi Direct, and 8) Wireless Universal Serial Bus (Wireless USB). The wireless communication interface 173 may support wireless communication between the display device 100 and a wireless communication system, between the display device 100 and another display device 100, or between the display device 100 and a network in which the display device 100 (or an external server) is located, via a short-range wireless communication network. The short-range wireless communication network may be a wireless personal area network.

[0047] Here, the other display apparatus 100 may be a wearable device (e.g., a smart watch, smart glasses, or a head mounted display (HMD)) or a mobile terminal such as a smartphone, which can exchange data with (or link with) the display apparatus 100 according to the present invention. The wireless communication interface 173 can detect (or recognize) a wearable device that can communicate with the display apparatus 100 around the display apparatus 100.

[0048] Furthermore, if the detected wearable device is a device authenticated to communicate with the display device 100 according to the present invention, the controller 170 can transmit at least a portion of the data processed in the display device 100 to the wearable device via the wireless communication interface 173. Thus, a user of the wearable device can use the data processed in the display device 100 through the wearable device.

[0049] The display 180 can generate drive signals by converting the video signals, data signals, and OSD signals processed in the controller 170 or the video signals and data signals received at the external device interface 135 into R, G, and B signals, respectively.

[0050] Meanwhile, the display device 100 shown in FIG. 1 is merely one embodiment of the present invention, and some of the illustrated components may be integrated, added, or omitted depending on the specifications of the display device 100 actually implemented.

[0051] That is, two or more components may be combined into one component, or one component may be divided into two or more components, as necessary. Furthermore, the functions performed in each block are for the purpose of explaining the embodiments of the present invention, and the specific operations and devices thereof do not limit the scope of the present invention.

[0052] According to another embodiment of the present invention, the display device 100 may receive and play back images via a network interface 133 or an external device interface 135, unlike the illustration of FIG. 1, without including a tuner 131 and a demodulator 132.

[0053] For example, the display device 100 may be realized by separating it into a video processing device such as a set-top box for receiving broadcast signals or content via various network services, and a content playback device for playing back content input from the video processing device.

[0054] In this case, the operating method of the display device according to the embodiment of the present invention described below may be performed not only by the display device 100 as described with reference to FIG. 1, but also by any one of a video processing device such as a separate set-top box or a content playback device having a display 180 and a speaker 185.

[0055] Next, a remote control device according to an embodiment of the present invention will be described with reference to FIGS.

[0056] FIG. 2 is a block diagram of a remote control device according to an embodiment of the present invention, and FIG. 3 shows an example of the actual configuration of a remote control device 200 according to an embodiment of the present invention.

[0057] Referring first to FIG. 2, a remote control device 200 may include a fingerprint recognition device 210, a wireless communication circuit 220, a user input interface 230, a sensor 240, an output interface 250, a power supply circuit 260, a memory 270, a controller 280, and a microphone 290.

[0058] Referring to FIG. 2, a wireless communication circuit 220 transmits and receives signals to and from any one of the display devices according to the above-described embodiments of the present invention.

[0059] The remote control device 200 may include an RF circuit 221 capable of transmitting and receiving signals to and from the display device 100 according to an RF communication standard, and an IR circuit 223 capable of transmitting and receiving signals to and from the display device 100 according to an IR communication standard. The remote control device 200 may also include a Bluetooth circuit 225 capable of transmitting and receiving signals to and from the display device 100 according to a Bluetooth communication standard. The remote control device 200 may also include an NFC (Near Field Communication) circuit 227 capable of transmitting and receiving signals to and from the display device 100 according to an NFC communication standard, and a WLAN (Wireless LAN) circuit 229 capable of transmitting and receiving signals to and from the display device 100 according to a WLAN communication standard.

[0060] In addition, the remote control device 200 transmits a signal including information about the movement of the remote control device 200 to the display device 100 via the wireless communication circuit 220 .

[0061] Meanwhile, the remote control device 200 receives signals transmitted by the display device 100 via the RF circuit 221, and can transmit commands regarding power on / off, channel change, volume change, etc. to the display device 100 via the IR circuit 223 as necessary.

[0062] The user input interface 230 may be configured with a keypad, buttons, a touchpad, a touch screen, or the like. A user can operate the user input interface 230 to input commands related to the display device 100 to the remote control device 200. If the user input interface 230 includes hard key buttons, the user can input commands related to the display device 100 to the remote control device 200 by pushing the hard key buttons. This will be described with reference to FIG. 3.

[0063] 3, the remote control device 200 may include a plurality of buttons, including a fingerprint recognition button 212, a power button 231, a home button 232, a live button 233, an external input button 234, a volume control button 235, a voice recognition button 236, a channel change button 237, a confirm button 238, and a back button 239.

[0064] The fingerprint recognition button 212 may be a button for recognizing a user's fingerprint. In one embodiment, the fingerprint recognition button 212 is capable of a push operation and can receive a push operation and a fingerprint recognition operation.

[0065] The power button 231 may be a button for turning the power of the display device 100 on and off.

[0066] The home button 232 may be a button for moving to the home screen of the display device 100.

[0067] The live button 233 may be a button for displaying real-time broadcast programs.

[0068] The external input button 234 may be a button for receiving an external input connected to the display device 100 .

[0069] The volume control button 235 may be a button for adjusting the volume of the sound output by the display device 100.

[0070] The voice recognition button 236 may be a button for receiving a user's voice and recognizing the received voice.

[0071] The channel change button 237 may be a button for receiving a broadcast signal of a specific broadcast channel.

[0072] The confirmation button 238 may be a button for selecting a specific function, and the back button 239 may be a button for returning to a previous screen.

[0073] Referring again to FIG.

[0074] If the user input interface 230 includes a touch screen, the user can touch soft keys on the touch screen to input commands related to the display device 100 to the remote control device 200. The user input interface 230 may also include various types of input means that can be operated by the user, such as a scroll key or a jog key, and this embodiment does not limit the scope of the present invention.

[0075] The sensor 240 may include a gyro sensor 241 or an acceleration sensor 243 , and the gyro sensor 241 may sense information regarding the movement of the remote control device 200 .

[0076] For example, the gyro sensor 241 can sense information about the operation of the remote control device 200 based on the x-, y-, and z-axes, and the acceleration sensor 243 can sense information about the moving speed of the remote control device 200. Meanwhile, the remote control device 200 can further include a distance measurement sensor, thereby sensing the distance from the display 180 of the display device 100.

[0077] The output interface 250 can output a video or audio signal corresponding to an operation of the user input interface 230 or a signal transmitted from the display device 100 .

[0078] The user can recognize whether the output interface 250 is operating the user input interface 230 or controlling the display device 100 .

[0079] For example, the output interface 250 may include an LED 251 that lights up when the user input interface 230 is operated or a signal is sent or received from the display device 100 via the Bluetooth circuit 225, a vibrator 253 that generates vibrations, a speaker 255 that outputs sound, or a display 257 that outputs images.

[0080] In addition, the power supply circuit 260 supplies power to the remote control device 200, and cuts off the power supply if the remote control device 200 is not in operation for a predetermined period of time, thereby reducing power consumption.

[0081] The power supply circuit 260 can resume power supply when a predetermined key provided on the remote control device 200 is operated.

[0082] The memory 270 can store various types of programs, application data, etc. required for the control or operation of the remote control device 200 .

[0083] When the remote control device 200 transmits and receives signals wirelessly to and from the display device 100 via the RF circuit 221, the remote control device 200 and the display device 100 transmit and receive signals via a predetermined frequency band.

[0084] The controller 280 of the remote control device 200 can store and refer to information in the memory 270 about a frequency band that can wirelessly transmit and receive signals to and from the display device 100 paired with the remote control device 200 .

[0085] The controller 280 controls various matters related to the control of the remote control device 200. The controller 280 can transmit a signal corresponding to a predetermined key operation on the user input interface 230 or a signal corresponding to the movement of the remote control device 200 sensed by the sensor 240 to the display device 100 via the Bluetooth circuit 225.

[0086] Additionally, the microphone 290 of the remote control device 200 can pick up audio.

[0087] A plurality of microphones 290 may be provided.

[0088] Next, FIG. 4 will be described.

[0089] FIG. 4 illustrates an example of utilizing a remote control device according to an embodiment of the present invention.

[0090] FIG. 4( a ) illustrates an example in which a pointer 205 corresponding to the remote control device 200 is displayed on the display 180 .

[0091] The user can move or rotate the remote control device 200 up, down, left, right, and so on. A pointer 205 displayed on the display 180 of the display device 100 corresponds to the movement of the remote control device 200. Such a remote control device 200 may be called a spatial remote control because the corresponding pointer 205 moves and is displayed according to the movement in the 3D space as shown in the drawing.

[0092] FIG. 4(b) illustrates that when the user moves the remote control device 200 to the left, the pointer 205 displayed on the display 180 of the display device 100 also moves to the left correspondingly.

[0093] Information about the movement of the remote control device 200 sensed by the sensor of the remote control device 200 is transmitted to the display device 100. The display device 100 can calculate the coordinates of the pointer 205 from the information about the movement of the remote control device 200. The display device 100 can display the pointer 205 according to the calculated coordinates.

[0094] 4(c) illustrates an example in which, while pressing a specific button on the remote control device 200, the user moves the remote control device 200 away from the display 180. This allows the selected area on the display 180 corresponding to the pointer 205 to be zoomed in and enlarged.

[0095] Conversely, if the user moves the remote control device 200 closer to the display 180, the selected area in the display 180 corresponding to the pointer 205 may be zoomed out.

[0096] On the other hand, when the remote control device 200 moves away from the display 180, the selection area may be zoomed out, and when the remote control device 200 moves closer to the display 180, the selection area may be zoomed in.

[0097] In addition, recognition of up, down, left, and right movement can be eliminated when a specific button on the remote control device 200 is pressed. That is, when the remote control device 200 is moved away from or toward the display 180, up, down, left, and right movement is not recognized, and only forward and backward movement can be recognized. When a specific button on the remote control device 200 is not pressed, only the pointer 205 moves in response to up, down, left, and right movement of the remote control device 200.

[0098] On the other hand, the moving speed and direction of the pointer 205 can correspond to the moving speed and direction of the remote control device 200 .

[0099] Meanwhile, the term "pointer" as used herein refers to an object displayed on the display 180 in response to the operation of the remote control device 200. Therefore, the pointer 205 may be an object of various shapes in addition to the arrow shape shown in the drawings. For example, the pointer may be a concept including a point, a cursor, a prompt, a thick outline, etc. The pointer 205 may be displayed corresponding to a single point on either the horizontal or vertical axis on the display 180, or may be displayed corresponding to multiple points such as a line or a surface.

[0100] FIG. 5 is a diagram illustrating the internal configuration of an organic light emitting diode (OLED) display when the display of FIG. 2 is realized by an OLED display.

[0101] The OLED display 180-1 may include a panel 510, a first interface 530, a second interface 531, a timing controller 532, a gate driver 534, a data driver 536, a memory 540, a processor 570, and a power supply circuit 590.

[0102] The OLED display 180-1 receives a video signal Vd, a first DC power supply V1, and a second DC power supply V2, and can display a predetermined image based on the video signal Vd.

[0103] The first interface 530 in the OLED display 180-1 can receive the video signal Vd from the controller 170 and the first DC power supply V1.

[0104] The first DC power supply V1 may be used to operate the power supply circuit 590 and the timing controller 532 in the OLED display 180-1.

[0105] The second interface 531 can receive a second DC power supply (V2) from the external power supply circuit 190. The second DC power supply V2 can be input to a data driver 536 in the OLED display 180-1.

[0106] The timing controller 532 can output a data driving signal Sda and a gate driving signal Sga based on the video signal Vd.

[0107] For example, when the first interface 530 converts the input video signal Vd and outputs the converted video signal va1, the timing controller 532 can output the data driving signal Sda and the gate driving signal Sga based on the converted video signal va1.

[0108] The timing controller 532 can receive not only the video signal Vd from the controller 170 but also control signals, a vertical synchronization signal Vsync, and the like.

[0109] In addition to the video signal Vd, the timing controller 532 can output a gate drive signal Sga for operating the gate driver 534 and a data drive signal Sda for operating the data driver 536 based on control signals, a vertical synchronization signal Vsync, etc.

[0110] If the panel 510 has RGBW subpixels, the data drive signal Sda may be a data drive signal for driving RGBW subpixels.

[0111] The timing controller 532 can further output a control signal Cs to the gate driver 534 .

[0112] The gate driver 534 and the data driver 536 supply scanning signals and video signals to the panel 510 via the gate lines GL and the data lines DL, respectively, in response to the gate driving signal Sga and the data driving signal Sda from the timing controller 532. This causes the panel 510 to display a predetermined image.

[0113] The panel 510 may include an organic light-emitting layer, and a number of gate lines GL and data lines DL are arranged in a matrix to cross each pixel corresponding to the organic light-emitting layer in order to display an image.

[0114] The data driver 536 can output a data signal to the panel 510 based on the second DC power supply V2 from the second interface 531.

[0115] The power supply circuit 590 can supply various power sources to the gate driver 534, the data driver 536, the timing controller 532, and the like.

[0116] The processor 570 can perform various controls within the OLED display 180-1, such as controlling the gate driver 534, the data driver 536, and the timing controller 532.

[0117] 6a-6b are diagrams referred to in the description of the OLED display of FIG.

[0118] First, Figure 6a is a diagram illustrating a pixel in a panel 510. The panel 510 may be an organic light-emitting panel.

[0119] The panel 510 may include a plurality of scan lines Scan 1 to Scan n and a plurality of data lines R 1 , G 1 , B 1 , W 1 to Rm, Gm, Bm, and Wm intersecting the scan lines.

[0120] A pixel is defined at the intersection of a scan line and a data line in the panel 510. In the drawing, a pixel having RGBW sub-pixels SPr1, SPg1, SPb1, and SPw1 is shown.

[0121] Although Fig. 6a illustrates that one pixel has RGBW sub-pixels, one pixel may also have RGB sub-pixels, i.e., there is no limitation on the pixel element arrangement type.

[0122] FIG. 6b illustrates the circuit of any one of the sub-pixels in the pixel of the organic light-emitting panel of FIG. 6a.

[0123] The organic light-emitting sub-pixel circuit CRTm may be an active type, and may include a scan switching element SW1, a storage capacitor Cst, a drive switching element SW2, and an organic light-emitting layer OLED.

[0124] The scan switching element SW1 has a gate terminal connected to a scan line and is turned on by an input scan signal Vscan, and when turned on, transfers an input data signal Vdata to the gate terminal of the driving switching element SW2 or one end of the storage capacitor Cst.

[0125] The storage capacitor Cst is formed between the gate terminal and the source terminal of the driving switching element SW2 and stores a predetermined difference between the data signal level transmitted to one end of the storage capacitor Cst and the DC power supply (Vdd) level transmitted to the other end of the storage capacitor Cst.

[0126] For example, when a data signal has different levels according to a PAM (Pulse Amplitude Modulation) method, the power supply level stored in the storage capacitor Cst changes according to the level difference of the data signal (Vdata).

[0127] As another example, when the data signal has different pulse widths according to a Pulse Width Modulation (PWM) method, the power supply level stored in the storage capacitor Cst changes according to the difference in the pulse width of the data signal (Vdata).

[0128] The driving switching element SW2 is turned on by the power supply level stored in the storage capacitor Cst. When the driving switching element SW2 is turned on, a driving current IOLED proportional to the stored power supply level flows to the organic light emitting layer OLED, causing the organic light emitting layer OLED to emit light.

[0129] The organic light-emitting layer OLED includes an RGBW light-emitting layer EML corresponding to a subpixel, and may include at least one of a hole injection layer HIL, a hole transport layer HTL, an electron transport layer ETL, and an electron injection layer EIL, and may also include a hole blocking layer.

[0130] Meanwhile, all sub-pixels in the organic light-emitting layer OLED output white light, but green, red, and blue sub-pixels require separate color filters to achieve the desired colors. That is, green, red, and blue sub-pixels require separate green, red, and blue color filters, respectively. Meanwhile, white sub-pixels do not require separate color filters because they output white light.

[0131] In the drawings, the scan switching element SW1 and the drive switching element SW2 are exemplified as p-type MOSFETs, but n-type MOSFETs or other switching elements such as JFETs, IGBTs, or SICs can also be used.

[0132] FIG. 7 is a flowchart illustrating an operation method of a signal processing device of an OLED display device according to an embodiment of the present disclosure.

[0133] OLED display 180-1 of FIG. 5 may be referred to as an OLED display device.

[0134] In the following embodiment, a method for operating the signal processing device of the OLED display device 180-1 of Fig. 5 will be described. In particular, a device including the memory 540 and the processor 570 included in the OLED display device 180-1 may be named a signal processing device.

[0135] In the following embodiments, each of the pixels included in the panel 510 may include a red subpixel, a green subpixel, and a blue subpixel, or may include a red subpixel, a green subpixel, a blue subpixel, and a white subpixel.

[0136] In one embodiment, each pixel included in panel 510 may include as many OLED elements (or organic light-emitting layers) as the number of subpixels.

[0137] In another embodiment, each pixel included in the panel 510 may include one OLED element. In this case, the color of each sub-pixel may be expressed through a color filter. Typically, a large-sized OLED display may have one OLED element per pixel.

[0138] The processor 570 receives an input video signal (S701).

[0139] The processor 570 may receive an input video signal from the first interface 530. The first interface 530 may receive an input video signal from either the broadcast receiving unit 130 or the external device interface 135 of FIG.

[0140] The processor 570 obtains an input gray level corresponding to the input video signal (S703).

[0141] In one embodiment, the input gray level may be calculated based on the image data of the input image signal. The processor 570 may obtain the input gray level as one of levels 0 to 255 using the image data of the input image signal on an 8-bit basis.

[0142] Level 0 represents the darkest black, and level 255 represents the brightest white.

[0143] The gray level can indicate the degree of brightness of a pixel.

[0144] Alternatively, the range of gray levels may range from 0 to 2047 levels on an 11-bit basis.

[0145] In the following description, it is assumed that a pixel includes a red subpixel, a green subpixel, a blue subpixel, and a white subpixel.

[0146] The processor 570 can calculate the input gray levels of the input image signal using red, green, blue, and white data values ​​included in the image data of the input image signal. Each of the red, green, blue, and white data values ​​included in the image data is a gray level or can be converted to a gray level.

[0147] In one embodiment, the processor 570 may obtain the maximum value among the red data value, the green data value, the blue data value, and the white data value as the input gray level when the pixel comprises one OLED element.

[0148] In yet another embodiment, the processor 570 may obtain as the input gray level the average of the red data value, the green data value, the blue data value, and the white data value when the pixel comprises one OLED element.

[0149] In another embodiment, when a pixel has one OLED element, the processor 570 may calculate the input gray level by applying a weighting value to each of the red data value, green data value, blue data value, and white data value included in the image data.

[0150] In this case, the input gray level can be expressed as Wr*R+Wg*G+Wb*B+Ww*W, where R is the red data value, G is the green data value, B is the blue data value, and W is the white data value, and Wr, Wg, Wb, and Ww are weights for each sub-pixel. The weights can be values ​​that can be changed depending on the characteristics of the image.

[0151] In yet another embodiment, when each of the sub-pixels in a pixel comprises an OLED element, the processor 570 can obtain a red data value, a green data value, a blue data value, and a white data value as input gray levels for the sub-pixels.

[0152] In yet another embodiment, the processor 570 may obtain the maximum value among the red data value, the green data value, the blue data value, and the white data value as the input gray level when each of the subpixels included in the pixel includes an OLED element.

[0153] The processor 570 compares the acquired input gray level with the reference gray level (S705).

[0154] In one embodiment, the reference gray level may be the minimum level required to turn on an OLED element included in a pixel, and may be a digital signal level at which the minimum brightness of the panel 510 is represented.

[0155] The reference gray level may be 8 levels, but this is merely an example. The reference gray level may also vary depending on the OLED display device. That is, the reference gray level may vary depending on the product due to mass production variations.

[0156] The reference gray level may be a level at which the OLED element lights up when a video signal is applied to the pixel or sub-pixel. The reference gray level may be stored in memory 540.

[0157] The OLED element may be designated as the organic light-emitting layer OLED in Figure 6b. In order for the OLED element to be turned on and emit light, a current must flow through the OLED element.

[0158] The gray level required for current to flow through the OLED element may be the reference gray level, that is, when the gray level of the input image signal is equal to or higher than the reference gray level, current can flow through the OLED element.

[0159] If the input gray level of the input video signal is less than the reference gray level (S707), the processor 570 generates a compensation level based on the input gray level and the reference gray level (S709).

[0160] When the input gray level applied to a pixel is less than the reference gray level, the processor 570 can generate a compensation level based on the difference between the input gray level and the reference gray level.

[0161] The compensation level may be the 0 level or the difference between the reference gray level and the input gray level.

[0162] That is, if the input gray level of the input image signal is lower than the reference gray level, the processor 570 may determine that the gray level of the output image signal output to the timing controller 532 is 0 or the reference gray level.

[0163] The processor 570 may generate an output gray level by adding the compensation level to the input gray level, and may transmit an output image signal corresponding to the generated output gray level to the timing controller 532.

[0164] The processor 570 can generate an output gray level based on the following equation:

[0165]

number

[0166] where input gray is the input gray level and turn on gray is the reference gray level. n is a uniform random variable that can have a constant probability in all regions within [0, y]. P(x, y) can be the probability density function of the uniform random variable n.

[0167] The processor 570 may determine the output gray level minus the input gray level as the compensation level.

[0168] When the input gray level is smaller than the reference gray level, the closer the input gray level is to the reference gray level, the more likely the processor 570 will output the input gray level as the reference gray level. That is, when the input gray level is smaller than the reference gray level, the closer the input gray level is to the reference gray level, the more likely the processor 570 will convert the input gray level to the reference gray level. The conversion frequency may be the frequency at which an OLED element of a pixel or subpixel is turned on.

[0169] When the input gray level is smaller than the reference gray level, the processor 570 may reduce the probability of outputting the input gray level as the reference gray level as the input gray level becomes farther from the reference gray level. That is, when the input gray level is smaller than the reference gray level, the processor 570 may reduce the frequency of converting the input gray level to the reference gray level as the input gray level becomes farther from the reference gray level.

[0170] Assume the reference gray level is 8.

[0171] When the input gray level of the input video signal is 6, the processor 570 can obtain the probability of converting the gray level of the input video signal to the reference gray level as 6 / 8.

[0172] When the input gray level of the input video signal is 2, the processor 570 can obtain the probability of converting the gray level of the input video signal to the reference gray level as 2 / 8.

[0173] When the input gray level of the input image signal is converted to a reference gray level, a current can be applied to an OLED element provided in the corresponding pixel or sub-pixel.

[0174] That is, when the input gray level of the input image signal approaches the reference gray level, the OLED element provided in the corresponding pixel or sub-pixel can be turned on, thereby allowing the corresponding pixel or sub-pixel to output the minimum brightness.

[0175] FIG. 8a is a diagram showing the output gray level when the input gray level is less than the reference gray level according to the prior art, and FIG. 8b is a diagram showing the output gray level when the input gray level is less than the reference gray level according to an embodiment of the present disclosure.

[0176] 8a and 8b, it is assumed that the reference gray level is x1, which may be 8 levels, but this is merely an example value and may vary depending on the OLED display device.

[0177] 8a and 8b, if the input gray level of the input image signal is equal to or greater than the reference gray level (x1), the input gray level can be output to the timing controller 532 as is.

[0178] Referring to Figure 8a, when the input gray level of the input video signal is smaller than the reference gray level (x1), the conventional OLED display device adjusts the output gray level to 0. This is because the input gray level does not meet the minimum reference gray level required to pass current through the OLED element.

[0179] According to the prior art, the OLED element does not light up until the input gray level reaches the reference gray level, and when the input gray level reaches the reference gray level, the OLED element lights up, generating a discontinuous output.

[0180] This not only makes it impossible to correctly represent the video signal, but also causes large steps in discontinuous output sections, resulting in visually unnatural results.

[0181] 8b, even if the input gray level of the input image signal is lower than the reference gray level (x1), the OLED display device 180-1 according to the embodiment of the present disclosure can convert the input gray level to the reference gray level (x1) based on the degree to which the input gray level is close to the reference gray level (x1). A compensation level is added to the input gray level, so that the output gray level is converted to the reference gray level (x1).

[0182] The smaller the difference between the input gray level and the reference gray level (x1), the more frequently the input gray level is converted to the reference gray level (x1).

[0183] The greater the difference between the input gray level and the reference gray level (x1), the less frequently the input gray level is converted to the reference gray level (x1).

[0184] According to the embodiments of the present disclosure, the OLED element can be turned on even when the input gray level of the input video signal is less than the reference gray level.

[0185] That is, the OLED display device 180-1 according to the embodiment of the present disclosure can intentionally degrade or drop the input image signal even in a section where the input gray level of the input image signal is smaller than the reference gray level, thereby eliminating visual unnaturalness that occurs in discontinuous output sections.

[0186] Referring again to FIG.

[0187] The processor 570 transfers the output video signal based on the generated compensation level to the timing controller (T-CON 532) (S711).

[0188] The processor 570 may obtain an output gray level by applying a compensation level to an input gray level of the input image signal, and may transmit an output image signal having the obtained output gray level to the timing controller 532.

[0189] The timing controller 532 transfers the received output image signal to the data driver 536 to drive the OLED element of the corresponding pixel or sub-pixel.

[0190] If the input gray level is equal to or greater than the reference gray level (S707), the processor 570 of the OLED display device 180-1 transmits the input image signal to the timing controller 532 (S713).

[0191] If the input gray level of the input image signal is equal to or greater than the reference gray level, the processor 570 may determine that the minimum condition for turning on the OLED element included in the pixel or sub-pixel is satisfied.

[0192] The timing controller 532 transfers an input image signal received from the processor 570 to the data driver 536 to drive an OLED element included in a corresponding pixel or sub-pixel.

[0193] FIG. 9 is a diagram illustrating the operation of a signal compensator according to an embodiment of the present disclosure.

[0194] The processor 570 may include a signal compensator 900. The signal compensator 900 may be provided in a configuration separate from the processor 570.

[0195] The signal compensator 900 may receive the input gray levels of the input video signal from the processor 570 .

[0196] The signal compensator 900 may receive a turn-on gray level from the processor 570. The turn-on gray level may be a digital signal level at which the minimum brightness of a pixel or subpixel is represented. The turn-on gray level may be a reference gray level.

[0197] The signal compensator 900 can convert the input gray level to 0 or a turn-on gray level based on a data range.

[0198] The probabilistic distribution range may follow the probability density function P(x,y) of the uniform random variable n described in step S709.

[0199] The signal compensator 900 can adjust the compensation level according to a probability density function when the input gray level is less than the turn-on gray level, and the compensation level can be the difference between the input gray level and the reference gray level.

[0200] When the input gray level is smaller than the turn-on gray level, the signal compensator 900 may increase the probability or frequency of converting the input gray level to the reference gray level as the difference between the turn-on gray level and the input gray level decreases.

[0201] When the input gray level is lower than the turn-on gray level, the signal compensator 900 may reduce the probability or frequency of converting the input gray level to the reference gray level as the difference between the turn-on gray level and the input gray level increases.

[0202] FIG. 10 is a diagram illustrating the result of improving the expressiveness in the extremely low gradation range by applying the embodiment of the present disclosure.

[0203] (a) of FIG. 10 is an input image 1010, (b) of FIG. 10 is an output image 1030 output through a panel 510 according to conventional technology, and (c) of FIG. 10 is a compensated output image 1050 output after compensation for the extremely low grayscale region of the input image 1010 according to an embodiment of the present disclosure.

[0204] The first extremely low gray scale region 1011 of the input image 1010 can be converted into a second extremely low gray scale region 1031 of the output image 1030 that generates visual unnaturalness through the panel 510 and output.

[0205] This is because the input gray level for driving the OLED element in the extremely low gray scale region is not satisfied.

[0206] In contrast, referring to (c) of FIG. 10, when a compensation level is applied to the second extremely low gradation region 1031 according to an embodiment of the present disclosure, a compensated output image 1050 including a third extremely low gradation region 1051 having improved expressiveness compared to the second extremely low gradation region 1031 can be output through the panel 510.

[0207] As described above, according to the embodiment of the present disclosure, the phenomenon of missing video signals representing dark brightness in an OLED display can be eliminated, thereby improving the expressiveness of extremely low gray levels representing dark brightness.

[0208] In addition, even if the reference gray level differs for each OLED display device, the expressiveness of the very low gray level area is improved based on the reference gray level, so that mass production deviations can be alleviated.

[0209] FIG. 11 is a diagram illustrating the configuration of a signal processing device for an OLED display according to an embodiment of the present disclosure.

[0210] The signal processing device 1100 of the organic light emitting diode (OLED) display 180-1 may include a memory 540 that stores a reference gray level, which is a minimum level for turning on an OLED element provided in a pixel or subpixel, and a processor 570 that acquires an input gray level corresponding to an input image signal, generates a compensation level based on the input gray level and the reference gray level if the acquired input gray level is lower than the reference gray level, acquires an output gray level based on the generated compensation level, and transmits an output image signal corresponding to the acquired output gray level to a timing controller 532.

[0211] The processor 570 can compensate the input gray level with a 0 level or the reference gray level based on the generated compensation level.

[0212] The processor 570 may obtain the difference between the input gray level and the reference gray level as the compensation level.

[0213] When the acquired input gray level is smaller than the reference gray level, the processor 570 may increase the probability of converting the input gray level to the reference gray level as the difference between the input gray level and the reference gray level decreases, and may decrease the probability of converting the input gray level to the reference gray level as the difference between the input gray level and the reference gray level increases.

[0214] When the acquired input gray level is smaller than the reference gray level, the processor 570 may increase the frequency of converting the input gray level to the reference gray level as the difference between the input gray level and the reference gray level decreases, and may decrease the frequency of converting the input gray level to the reference gray level as the difference between the input gray level and the reference gray level increases.

[0215] When the pixel includes one OLED element, the processor 570 may obtain the maximum value among the red data value, the green data value, the blue data value, and the white data value of the input image signal as the input gray level.

[0216] When an OLED element is provided in each of the red sub-pixel, green sub-pixel, blue sub-pixel, and white sub-pixel constituting the pixel, the processor 570 may obtain the red data value, green data value, blue data value, and white data value of the input image signal as the input gray level, respectively.

[0217] The OLED display device 180-1 may include a signal processing device 1100, an OLED panel 510 including a plurality of pixels, a data driver 536 that outputs a data signal to the OLED panel 510, a gate driver 534 that outputs a gate signal to the OLED panel 510, and a timing controller 532 that transmits a data driving signal to the data driver 536 and transmits a gate driving signal to the gate driver 534 based on the output video signal.

[0218] According to one embodiment of the present disclosure, the above-described method may be implemented as processor-readable code on a program-recorded medium, examples of which include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device, etc.

[0219] The display device described above is not limited to the configurations and methods of the above-described embodiments, but may be configured by selectively combining all or part of each embodiment to allow for various modifications.

Claims

1. 1. A signal processing device for an organic light emitting diode (OLED) display, comprising: a memory for storing reference gray levels; and a processor; the reference gray level is a minimum level for turning on an OLED element included in a pixel or subpixel, The processor: Obtaining an input gray level corresponding to an input video signal; If the acquired input gray level is less than the reference gray level, generating a compensation level based on the input gray level and the reference gray level; Obtaining an output gray level based on the generated compensation level; and a signal processing device configured to transmit an output video signal corresponding to the obtained output gray level to a timing controller;

2. The signal processing device of claim 1 , wherein the processor is further configured to compensate the input gray level with a 0 level or the reference gray level based on the generated compensation level.

3. The signal processing device of claim 2 , wherein the processor is configured to obtain a difference between the input gray level and the reference gray level as the compensation level.

4. If the acquired input gray level is less than the reference gray level, increasing the probability of converting the input gray level to the reference gray level as the difference between the input gray level and the reference gray level decreases; and The signal processing device according to claim 3 , configured to reduce the probability of converting the input gray level to the reference gray level as the difference between the input gray level and the reference gray level increases.

5. If the acquired input gray level is less than the reference gray level, The smaller the difference between the input gray level and the reference gray level, the more frequently the input gray level is converted to the reference gray level; and The signal processing device according to claim 3 , configured to reduce the frequency of converting the input gray level to the reference gray level as the difference between the input gray level and the reference gray level increases.

6. When the pixel is provided with one OLED element, the processor 2. The signal processing device according to claim 1, configured to obtain the maximum value among red, green, blue and white data values ​​of the input video signal as the input gray level.

7. When an OLED element is provided for each of a red subpixel, a green subpixel, a blue subpixel, and a white subpixel that constitute the pixel, the processor 2. The signal processing device of claim 1, configured to obtain red, green, blue and white data values ​​of the input video signal as the input grey levels, respectively.

8. 1. An OLED display device, comprising: A signal processing device according to claim 1; an OLED panel including a plurality of pixels; a data driver that outputs a data signal to the OLED panel; a gate driver that outputs a gate signal to the OLED panel; and a timing controller for transmitting a data driving signal to the data driver and a gate driving signal to the gate driver based on the output video signal.

9. 1. A method of operating a signal processing device for an Organic Light Emitting Diode (OLED) display, comprising: storing a reference gray level, which is the minimum level for turning on an OLED element included in a pixel or subpixel; obtaining an input gray level corresponding to an input video signal; generating a compensation level based on the input gray level and the reference gray level if the acquired input gray level is smaller than the reference gray level; obtaining an output gray level based on the generated compensation level; and transmitting an output video signal corresponding to the obtained output gray level to a timing controller.

10. 10. The method of claim 9, further comprising: compensating the input gray level with a 0 level or the reference gray level based on the generated compensation level.

11. 11. The method of claim 10, wherein generating the compensation level comprises obtaining a difference between the input gray level and the reference gray level as the compensation level.

12. If the acquired input gray level is smaller than the reference gray level, increasing the probability of converting the input gray level to the reference gray level as the difference between the input gray level and the reference gray level decreases; and 12. The method of claim 11, further comprising: when an acquired input gray level is smaller than the reference gray level, decreasing a probability of converting the input gray level to the reference gray level as the difference between the input gray level and the reference gray level increases.

13. If the acquired input gray level is smaller than the reference gray level, increasing the frequency of converting the input gray level to the reference gray level as the difference between the input gray level and the reference gray level decreases; and The method of claim 11 , further comprising: reducing the frequency of converting the input gray level to the reference gray level as the difference between the input gray level and the reference gray level increases.

14. 10. The method of claim 9, wherein the step of acquiring the input gray level comprises: acquiring a maximum value among a red data value, a green data value, a blue data value, and a white data value of the input video signal as the input gray level when the pixel is provided with one OLED element.

15. 10. The method of claim 9, wherein the step of acquiring the input gray level comprises acquiring a red data value, a green data value, a blue data value, and a white data value of the input video signal as the input gray level, respectively, when an OLED element is provided in each of a red sub-pixel, a green sub-pixel, a blue sub-pixel, and a white sub-pixel constituting the pixel.

Images