# US 2018/0025683 A1 · Display apparatus and method of operating the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0025683 A1 - Document ID: US20180025683A1 - Status: Published application - Kind: A1 - Application number: 15/459,657 - Filed: 2017-03-15 - Published: 2018-01-25 - Earliest claimed: 2016-07-22 - Assignees: Samsung Display Co., Ltd. - Applicants: Samsung Display Co., Ltd. - Inventors: HYUN-UK OH; Jl-TAE KIM - Web page: https://patentgrep.com/patent/US20180025683A1 ## CPC - G09G 3/3291: in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements - G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element - G09G 3/3258: with pixel circuitry controlling the voltage across the light-emitting element - G09G 2300/0408: Integration of the drivers onto the display substrate - G09G 2300/043: Compensation electrodes or other additional electrodes in matrix displays related to distortions or compensation signals, e.g. for modifying TFT threshold voltage in column driver - G09G 2300/0842: forming a memory circuit, e.g. a dynamic memory with one capacitor - G09G 2300/0861: with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes - G09G 2320/0238: Improving the black level - G09G 2320/0271: Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping - G09G 2320/0295: by monitoring each display pixel - G09G 2340/16: Determination of a pixel data signal depending on the signal applied in the previous frame - G09G 2360/16: Calculation or use of calculated indices related to luminance levels in display data - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract A display apparatus includes a display panel and a panel driver. The display panel includes a first pixel including a first organic light emitting diode (OLED). The panel driver applies a first voltage to an anode electrode of the first OLED while a first frame image is displayed on the display panel if a grayscale of the first frame image is lower than a first reference grayscale. ## Claims ### Claim 1 A display apparatus comprising: a display panel comprising a first pixel including a first organic light emitting diode (OLED); and a panel driver configured to apply a first voltage to an anode electrode of the first OLED while a first frame image is displayed on the display panel if a grayscale of the first frame image is lower than a first reference grayscale. ### Claim 2 (depends on 1) The display apparatus of claim 1, wherein the first voltage is an initialization voltage for resetting the first OLED. ### Claim 3 (depends on 2) The display apparatus of claim 2, wherein the first pixel further comprises: a first transistor connected between the anode electrode of the first OLED and a node receiving the initialization voltage, the first transistor having a gate electrode receiving a first initialization control signal. ### Claim 4 (depends on 3) The display apparatus of claim 3, wherein the panel driver comprises: a data driver configured to generate a first data signal based on image data corresponding to the first frame image; and an initialization controller configured to generate the first initialization control signal by checking the grayscale of the first frame image based on the first data signal. ### Claim 5 (depends on 4) The display apparatus of claim 4, wherein the initialization controller comprises: a comparator including a first input terminal receiving the first data signal, a second input terminal receiving a first reference signal corresponding to the first reference grayscale, and an output terminal outputting the first initialization control signal. ### Claim 6 (depends on 5) The display apparatus of claim 5, wherein when a voltage level of the first data signal is higher than a voltage level of the first reference signal, the initialization controller determines that the grayscale of the first frame image is lower than the first reference grayscale to activate the first initialization control signal, wherein the initialization voltage is applied to the anode electrode of the first OLED when the first initialization control signal is activated. ### Claim 7 (depends on 4) The display apparatus of claim 4, wherein the initialization controller is disposed on the display panel. ### Claim 8 (depends on 4) The display apparatus of claim 4, wherein the initialization controller is disposed within the data driver. ### Claim 9 (depends on 1) The display apparatus of claim 1, wherein the panel driver applies the first voltage to the anode electrode of the first OLED while the first frame image is displayed on the display panel if the grayscale of the first frame image is lower than the first reference grayscale and if a grayscale of a second frame image is higher than a second reference grayscale, wherein the first and second frame images are two consecutive images. ### Claim 10 (depends on 9) The display apparatus of claim 9, wherein the panel driver modifies the first frame image if the grayscale of the first frame image is lower than the first reference grayscale and if the grayscale of the second frame image is higher than the second reference grayscale. ### Claim 11 A method of operating a display apparatus comprising a display panel including a first pixel, the method comprising: comparing a grayscale of a first frame image displayed on the display panel with a first reference grayscale; and applying a first voltage to an anode electrode of a first organic light emitting diode (OLED) included in the first pixel while the first frame image is displayed on the display panel if a result of the comparing indicates the grayscale of the first frame image is lower than the first reference grayscale. ### Claim 12 (depends on 11) The method of claim 11, wherein the first voltage is an initialization voltage for resetting the first OLED. ### Claim 13 (depends on 12) The method of claim 12, wherein comparing the grayscale of the first frame image with the first reference grayscale comprises: generating a first data signal based on image data corresponding to the first frame image; and generating a first initialization control signal by comparing the first data signal with a first reference signal corresponding to the first reference grayscale. ### Claim 14 (depends on 13) The method of claim 13, wherein when a voltage level of the first data signal is higher than a voltage level of the first reference signal, it is determined that the grayscale of the first frame image is lower than the first reference grayscale to activate the first initialization control signal, wherein the initialization voltage is applied to the anode electrode of the first OLED when the first initialization control signal is activated. ### Claim 15 (depends on 11) The method of claim 11, further comprising: comparing a grayscale of a second frame image displayed on the display panel with a second reference grayscale, the first and second frame images being two consecutive images, wherein the first voltage is applied to the anode electrode of the first OLED while the first frame image is displayed on the display panel if the grayscale of the first frame image is lower than the first reference grayscale and if the grayscale of the second frame image is higher than the second reference grayscale. ### Claim 16 A display apparatus comprising: a display panel comprising a first pixel, the first pixel including: a first organic light emitting diode (OLED); and a first initialization circuit connected to the first OLED; and a panel driver configured to generate a first initialization control signal by comparing a grayscale of a first partial image displayed on the first pixel with a first reference grayscale, wherein when the first initialization control signal is activated, the first initialization circuit is enabled and applies an initialization voltage to the first OLED while the first partial image is displayed on the first pixel. ### Claim 17 (depends on 16) The display apparatus of claim 16, wherein the panel driver activates the first initialization control signal if the grayscale of the first partial image is lower than the first reference grayscale. ### Claim 18 (depends on 17) The display apparatus of claim 17, wherein the panel driver determines that the grayscale of the first partial image is lower than the first reference grayscale if a voltage level of a first data signal corresponding to the first partial image is higher than a voltage level of a first reference signal corresponding to the first reference grayscale. ### Claim 19 (depends on 16) The display apparatus of claim 16, wherein the panel driver generates the first initialization control signal by comparing the grayscale of the first partial image with the first reference grayscale, and by comparing a grayscale of a second partial image displayed on the first pixel with a second reference grayscale, wherein the first and second partial images are two consecutive images. ### Claim 20 (depends on 19) The display apparatus of claim 19, wherein the panel driver activates the first initialization control signal if the grayscale of the first partial image is lower than the first reference grayscale, and if the grayscale of the second partial image is higher than the second reference grayscale. ### Claim 21 (depends on 16) The display apparatus of claim 16, wherein the panel driver comprises: a data driver configured to generate a first data signal corresponding to the first partial image based on image data; and an initialization controller configured to generate the first initialization control signal by checking the grayscale of the first partial image based on the first data signal. ### Claim 22 (depends on 21) The display apparatus of claim 21, wherein the initialization controller comprises: a comparator including a first input terminal receiving the first data signal, a second input terminal receiving a first reference signal corresponding to the first reference grayscale, and an output terminal outputting the first initialization control signal. ### Claim 23 (depends on 21) The display apparatus of claim 21, wherein the initialization controller is disposed on the display panel. ### Claim 24 (depends on 21) The display apparatus of claim 21, wherein the initialization controller is disposed within the data driver. ### Claim 25 (depends on 16) The display apparatus of claim 16, wherein the first initialization circuit comprises: a first transistor connected between an anode electrode of the first OLED and a node receiving the initialization voltage, the first transistor having a gate electrode receiving the first initialization control signal. ### Claim 26 (depends on 25) The display apparatus of claim 25, wherein the initialization voltage is applied to the anode electrode of the first OLED. ### Claim 27 A display apparatus comprising: a display panel including a plurality of pixels; and a panel driver configured to modify a first frame image displayed on the display panel if a grayscale of the first frame image is lower than a first reference grayscale and if a grayscale of a second frame image displayed on the display panel is higher than a second reference grayscale, wherein the first and second frame images are two consecutive images. ### Claim 28 (depends on 27) The display apparatus of claim 27, wherein the panel driver increases the grayscale of the first frame image to a first grayscale if the grayscale of the first frame image is lower than the first reference grayscale and if the grayscale of the second frame image is higher than the second reference grayscale. ### Claim 29 (depends on 27) The display apparatus of claim 27, wherein the panel driver increases a grayscale of a first region in the first frame image to a first grayscale if the grayscale of the first region in the first frame image is lower than the first reference grayscale and if a grayscale of a first region in the second frame image is higher than the second reference grayscale, wherein the first region in the second frame image corresponds to the first region in the first frame image. ### Claim 30 (depends on 29) The display apparatus of claim 29, wherein the panel driver increases the grayscale of the first region in the first frame image to the first grayscale and increases a grayscale of a second region in the first frame image to a second grayscale if the grayscale of the second region in the first frame image is substantially equal to the first grayscale, wherein the second region in the first frame image is different from the first region in the first frame image, and wherein the second grayscale is higher than the first grayscale. ### Claim 31 A display apparatus comprising: a display panel comprising a pixel including a first transistor having a first non-gate electrode connected to a node receiving a first data signal and an organic light emitting diode (OLED); and a controller configured to receive a second data signal output by a second non-gate electrode of the first transistor, wherein the controller is configured to selectively disable the OLED based on how the second data signal compares to a first reference grayscale and a second reference grayscale that is higher than the first reference grayscale. ### Claim 32 (depends on 31) The display apparatus of claim 31, wherein the controller disables the OLED when a grayscale of the second data signal is less than the first reference grayscale during a first time and greater than the second reference grayscale during a second time. ### Claim 33 (depends on 32) The display apparatus of claim 32, wherein the pixel further comprises a second transistor connected between a node receiving a voltage configured to reset the OLED and an anode electrode of the OLED, and the controller applies a signal to a gate electrode of the second transistor to disable the OLED.