Display device, method for driving the same, and head-mounted display apparatus

Abstract

A display device, a method for driving the display device, and a head-mounted display apparatus are provided. The display device includes: a driving frequency calculator configured to divide output image data into a center image, an intermediate image, and a peripheral image corresponding to a center field-of-view region, an intermediate field-of-view region, and a peripheral field-of-view region, respectively; calculating spatial frequencies of the central image, the intermediate image and the peripheral image; calculating critical flicker frequencies for the central field of view region, the intermediate field of view region and the peripheral field of view region based on the spatial frequency and based on the field of view of the central field of view region, the intermediate field of view region and the peripheral field of view region; and determine driving frequencies for the central field of view, the intermediate field of view, and the peripheral field of view based on the critical flicker frequency; and a display panel configured to display an image based on the output image data and based on the driving frequency.

Description

Technical Field

[0001] Embodiments relate to an electronic device, to a display device, to a method for driving a display device, and to a head-mounted display device including the display device. Background Art

[0002] A head mounted display (HMD) device refers to an electronic device that is worn on the user's head like glasses to allow the user to receive visual information through the electronic device. In accordance with the trend toward lighter and smaller electronic devices, various wearable electronic devices are being developed, and head mounted display devices are also widely used.

[0003] Since the head mounted display device is worn on the user's head, the head mounted display device can be operated close to the user's eyes. Recently, various methods capable of improving the quality of images provided by the head mounted display device and reducing the power consumption of the head mounted display device are being studied. Summary of the invention

[0004] The embodiment provides a display device with improved image quality and reduced power consumption.

[0005] The embodiment provides a method for driving a display device with improved image quality and reduced power consumption.

[0006] Embodiments provide a head mounted display device with improved image quality and reduced power consumption.

[0007] According to an embodiment, a display device may include: a driving frequency calculator, configured to: divide the output image data into a central image, an intermediate image, and a peripheral image corresponding to the central field of view area, the intermediate field of view area, and the peripheral field of view area, respectively; calculate the spatial frequencies of the central image, the intermediate image, and the peripheral image; calculate the critical flicker frequencies of the central field of view area, the intermediate field of view area, and the peripheral field of view area based on the spatial frequencies and based on the viewing angles of the central field of view area, the intermediate field of view area, and the peripheral field of view area; and determine the driving frequencies of the central field of view area, the intermediate field of view area, and the peripheral field of view area based on the critical flicker frequencies; and a display panel, configured to display an image based on the output image data and based on the driving frequencies.

[0008] The output image data may include the input image data on which foveated rendering was performed.

[0009] The display device may further include a visual field tester configured to measure a central visual field area, an intermediate visual field area, and a peripheral visual field area through a visual field test.

[0010] The visual field tester can be configured to: set the area including the gaze point as the central visual field area; set the area surrounding the central visual field area as the intermediate visual field area; and set the area of ​​the entire visual field area except the central visual field area and the intermediate visual field area as the peripheral visual field area.

[0011] The spatial frequency can be calculated by performing a Fast Fourier Transform (FFT) on the central image, the intermediate images, and the peripheral images.

[0012] The spatial frequency of the peripheral image may be smaller than the spatial frequency of the central image.

[0013] The critical flicker frequency can be calculated by using the temporal contrast sensitivity function.

[0014] The driving frequency of the central field of view area, the driving frequency of the intermediate field of view area and the driving frequency of the peripheral field of view area can be greater than or equal to the critical flicker frequency of the central field of view area, the critical flicker frequency of the intermediate field of view area and the critical flicker frequency of the peripheral field of view area, respectively.

[0015] The display device may further include a renderer configured to convert input image data into output image data by performing foveated rendering on the input image data.

[0016] According to an embodiment, a method for driving a display device may include: dividing output image data into a central image, an intermediate image, and a peripheral image corresponding to a central field of view area, an intermediate field of view area, and a peripheral field of view area, respectively; calculating the spatial frequencies of the central image, the intermediate image, and the peripheral image; calculating critical flicker frequencies of the central field of view area, the intermediate field of view area, and the peripheral field of view area based on the spatial frequencies and based on the viewing angles of the central field of view area, the intermediate field of view area, and the peripheral field of view area; determining driving frequencies of the central field of view area, the intermediate field of view area, and the peripheral field of view area based on the critical flicker frequencies; and displaying an image based on the output image data and based on the driving frequencies.

[0017] The method may also include generating output image data by performing foveated rendering on the input image data.

[0018] The method may also include measuring the central visual field area, the intermediate visual field area, and the peripheral visual field area by visual field testing.

[0019] The method may also include setting the area including the gaze point as the central visual field area; setting the area surrounding the central visual field area as the intermediate visual field area; and setting the area of ​​the entire visual field area except the central visual field area and the intermediate visual field area as the peripheral visual field area.

[0020] The spatial frequencies may be calculated by performing a Fast Fourier Transform (FFT) on the central image, the intermediate images, and the peripheral images.

[0021] The spatial frequency of the peripheral image may be smaller than the spatial frequency of the central image.

[0022] The critical flicker frequency can be calculated by using the temporal contrast sensitivity function.

[0023] The driving frequency of the central field of view area, the driving frequency of the intermediate field of view area and the driving frequency of the peripheral field of view area can be greater than or equal to the critical flicker frequency of the central field of view area, the critical flicker frequency of the intermediate field of view area and the critical flicker frequency of the peripheral field of view area, respectively.

[0024] The method may further include converting the input image data into output image data by performing foveated rendering on the input image data.

[0025] According to an embodiment, a head-mounted display device includes: a processor, configured to convert input image data into output image data; and a display device, configured to display an image based on the output image data, and includes: a driving frequency calculator, configured to: divide the output image data into a central image, an intermediate image, and a peripheral image corresponding to the central field of view area, the intermediate field of view area, and the peripheral field of view area, respectively; calculate the spatial frequencies of the central image, the intermediate image, and the peripheral image; calculate the critical flicker frequencies of the central field of view area, the intermediate field of view area, and the peripheral field of view area based on the spatial frequencies and based on the viewing angles of the central field of view area, the intermediate field of view area, and the peripheral field of view area; and determine the driving frequencies of the central field of view area, the intermediate field of view area, and the peripheral field of view area based on the critical flicker frequencies; and a display panel, configured to display the image based on the output image data and based on the driving frequencies.

[0026] The processor may be configured to generate output image data by performing foveated rendering on input image data.

[0027] In a display device, a method for driving a display device, and a head-mounted display device according to one or more embodiments, the critical flicker frequency of the central visual field area, the intermediate visual field area, and the peripheral visual field area can be calculated based on the spatial frequency of the central image, the intermediate image, and the peripheral image. In addition, the driving frequency of the central visual field area, the intermediate visual field area, and the peripheral visual field area can be determined based on the critical flicker frequency, so that the user can visually not recognize the flicker, and the image quality of the display device and the head-mounted display device can be improved. In addition, the driving frequency can be controlled for each visual field area, so that the power consumption of the display device and the head-mounted display device can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Illustrative, non-limiting embodiments will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings.

[0029] Figure 1 is a block diagram illustrating a display device according to one or more embodiments of the present disclosure.

[0030] Figure 2 is used to describe the Figure 1 A view of the output image data of the driving frequency calculator of the display device.

[0031] Figure 3 It is used to describe the Figure 1 A view of the visual field tester in the display device.

[0032] Figure 4 It is used to describe the Figure 1 A view of the operation of the controller in the display device.

[0033] Figure 5 It is shown that the Figure 1 A block diagram of a driving frequency calculator in a display device.

[0034] Figure 6 It is used to describe the Figure 5 A view of the image divider in the Drive Frequency Calculator.

[0035] Figure 7 It is used to describe the Figure 5 A view of the Spatial Frequency Calculator in the Drive Frequency Calculator.

[0036] Figure 8 and Fig. 9 It is used to describe the Figure 5 A view of the Critical Flicker Frequency Calculator in the Drive Frequency Calculator.

[0037] Fig.10 is a block diagram illustrating a display device according to one or more embodiments of the present disclosure.

[0038] Fig.11 is a flowchart illustrating a method for driving a display device according to one or more embodiments of the present disclosure.

[0039] Fig.12 is a block diagram illustrating a head mounted display device according to one or more embodiments of the present disclosure.

[0040] Fig.13 It shows the realization Fig.12 An example view of a head mounted display device. DETAILED DESCRIPTION

[0041] By referring to the detailed description and drawings of the embodiments, it is easier to understand the aspects of some embodiments of the present disclosure and the methods for implementing them. The described embodiments are provided as examples so that the present disclosure will be thorough and complete, and the aspects of the present disclosure will be fully conveyed to those skilled in the art. Therefore, redundant, irrelevant or unrelated to the description of the embodiments, or processes, elements and techniques that are not necessary for a person of ordinary skill in the art to fully understand the various aspects of the present disclosure can be omitted. Unless otherwise stated, throughout the drawings and written descriptions, the same reference numerals, characters or combinations thereof represent the same elements, and therefore, their repeated descriptions can be omitted.

[0042] The described embodiments may have various modifications and may be implemented in different forms, and should not be construed as being limited to the embodiments shown herein. The use of "can", "may", or "may not" when describing an embodiment corresponds to one or more embodiments of the present disclosure. The present disclosure encompasses all modifications, equivalents, and substitutes within the conceptual and technical scope of the present disclosure. In addition, each of the features of the various embodiments of the present disclosure may be partially or completely combined with each other, and various interlocks and drives are technically possible. Each embodiment may be implemented independently of one another, or may be implemented together in association.

[0043] For the purposes of this disclosure, when expressions such as "at least one of ... " or "any one of ... " or "one or more of ... " are after (before) a list of elements, they modify the entire list of elements, without modifying the individual elements in the list. For example, "at least one of X, Y, and Z" and "at least one of the group consisting of X, Y, and Z" can be interpreted as only X, only Y, only Z, any combination of two or more of X, Y, and Z (such as XYZ, XYY, YZ, and ZZ as examples), or any variation thereof. Similarly, the expression "at least one of A and B" may include A, B, or A and B. As used herein, "or" generally means "and / or", and the term "and / or" includes any combination and all combinations of one or more of the relevant listed items. For example, the expression "A and / or B" may include A, B, or A and B. Similarly, expressions such as “at least one of,” “a plurality of,” “one of,” and other prepositional phrases when preceding (preceding) a list of elements modify the entire list of elements and do not modify the individual elements of the list.

[0044] It will be understood that, although the terms "first", "second", "third", etc. can be used here to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms do not correspond to a specific order, position or priority, and are only used to distinguish an element, member, component, region, area, layer, part or part from another element, member, component, region, area, layer, part or part. Therefore, without departing from the spirit and scope of the present disclosure, the first element, first component, first area, first layer or first part described below can be referred to as the second element, second component, second area, second layer or second part. Describing an element as a "first" element may not require or imply the presence of a second element or other elements. The terms "first", "second", etc. can also be used here to distinguish elements of different categories or sets. For the sake of simplicity, the terms "first", "second", etc. can respectively represent "first category (or first set)", "second category (or second set)", etc.

[0045] The terms used herein are only used for the purpose of describing the embodiments and are not intended to limit the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms "one" and "one (kind / person)" are also intended to include plural forms, and the plural forms are also intended to include singular forms. It will also be understood that when the terms "comprising", "having", "including" and variations thereof are used in this specification, the stated features, wholes, steps, operations, elements and / or components are indicated, but the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their groups are not excluded.

[0046] When one or more embodiments can be implemented differently, a specific process order can be performed differently from the described order. For example, two processes described in succession can be performed substantially simultaneously or in an order opposite to the described order.

[0047] As used herein, the terms "substantially", "about", "roughly" and similar terms are used as approximate terms rather than as terms of degree, and are intended to take into account the inherent deviations of measured or calculated values ​​that will be recognized by those of ordinary skill in the art. For example, "substantially" may include a range of + / - 5% of the corresponding value. "About" or "roughly" as used herein include the stated values ​​and mean: within the acceptable deviation range of the particular value as determined by those of ordinary skill in the art, taking into account the measurement in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system). For example, "about" may mean within one or more standard deviations, or within ±30%, ±20%, ±10%, ±5% of the stated value. In addition, when describing embodiments of the present disclosure, the use of "may" refers to "one or more embodiments of the present disclosure."

[0048] In some embodiments, known structures and devices may be described in the accompanying drawings with respect to one or more functional blocks (e.g., block diagrams), units, and / or modules to avoid making various embodiments unnecessarily obscure. It will be understood by those skilled in the art that such blocks, units, and / or modules are physically implemented by logic circuits, separate components, microprocessors, hard-wired circuits, memory elements, line connections, and other electronic circuits. This can be formed using semiconductor-based manufacturing techniques or other manufacturing techniques. Blocks, units, and / or modules implemented by microprocessors or other similar hardware can be programmed and controlled using software to perform the various functions discussed herein, and they can be selectively driven by firmware and / or software. In addition, each block, unit, and / or module can be implemented by a combination of dedicated hardware or dedicated hardware that performs some functions and a processor (e.g., one or more programmed microprocessors and related circuits) that performs functions different from those performed by the dedicated hardware. In addition, in some embodiments, without departing from the scope of the present disclosure, blocks, units, and / or modules can be physically divided into two or more interacting separate blocks, units, and / or modules. Additionally, in some embodiments, blocks, units and / or modules may be physically combined into more complex blocks, units and / or modules without departing from the scope of the present disclosure.

[0049] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by those skilled in the art to which the present disclosure belongs. It will also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and / or this specification, and should not be interpreted in an idealized or overly formal sense, unless explicitly defined as such herein.

[0050] Figure 1is a block diagram illustrating a display device 100 according to one or more embodiments of the present disclosure. Figure 2 is used to describe the Figure 1 FIG. 1 is a view of the output image data IMD2 of the driving frequency calculator 150 in the display device 100 . Figure 3 It is used to describe the Figure 1 A view of the visual field tester 160 in the display device 100. Figure 4 It is used to describe the Figure 1 FIG. 1 is a view of an operation of the controller 140 in the display device 100 .

[0051] Reference Figure 1 , the display device 100 may include a display panel 110 , a scan driver 120 , a data driver 130 , a controller 140 , a driving frequency calculator 150 , and a visual field tester 160 .

[0052] The display panel 110 may include pixels PX. According to one or more embodiments, the pixels PX may include a first pixel configured to emit light having a first color, a second pixel configured to emit light having a second color, and a third pixel configured to emit light having a third color. For example, the first color, the second color, and the third color may be red, green, and blue, respectively.

[0053] The scan driver 120 may provide a scan signal SS to the pixel PX. The scan driver 120 may sequentially generate first to n-th scan signals SS corresponding to the first to n-th pixel rows, respectively, based on the first control signal CNT1 (where n is a natural number greater than or equal to 2). The first control signal CNT1 may include a scan clock signal, a scan start signal, and the like.

[0054] The data driver 130 may provide a data signal DS to the pixel PX. The data driver 130 may generate first to m-th data signals DS corresponding to the first to m-th pixel columns, respectively, based on the corrected image data IMD3 and the second control signal CNT2 (where m is a natural number greater than or equal to 2). According to one or more embodiments, the corrected image data IMD3 may include grayscale level values ​​corresponding to the pixels PX, respectively. The second control signal CNT2 may include a data clock signal, a horizontal start signal, a load signal, etc.

[0055] The controller 140 may control the operation (or driving) of the scan driver 120 and the operation (or driving) of the data driver 130. The controller 140 may generate a first control signal CNT1, a second control signal CNT2, and correction image data IMD3 based on the output image data IMD2, based on the control signal CNT, and based on the first to third driving frequencies DF1, DF2, and DF3. According to one or more embodiments, the output image data IMD2 may include gray level values ​​corresponding to the pixels PX, respectively. The controller 140 may convert the output image data IMD2 into correction image data IMD3. The control signal CNT may include a main clock signal, a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, and the like. The first driving frequency DF1 may be a driving frequency of the central field of view region VR1, the second driving frequency DF2 may be a driving frequency of the intermediate field of view region VR2, and the third driving frequency DF3 may be a driving frequency of the peripheral field of view region VR3.

[0056] The driving frequency calculator 150 may divide the output image data IMD2 received from the outside into a central image, an intermediate image, and a peripheral image corresponding to the central visual field area VR1, the intermediate visual field area VR2, and the peripheral visual field area VR3 of the user, respectively. The driving frequency calculator 150 may also calculate the spatial frequencies of the central image, the intermediate image, and the peripheral image. The driving frequency calculator 150 may also calculate the critical flicker frequencies of the central visual field area VR1, the intermediate visual field area VR2, and the peripheral visual field area VR3 based on the spatial frequencies and the viewing angles of the central visual field area VR1, the intermediate visual field area VR2, and the peripheral visual field area VR3. In addition, the driving frequency calculator 150 may determine the driving frequencies DF1, DF2, and DF3 of the central visual field area VR1, the intermediate visual field area VR2, and the peripheral visual field area VR3 based on the critical flicker frequencies. The first driving frequency DF1 may be a driving frequency at which flicker is not visually recognized in the central visual field area VR1, the second driving frequency DF2 may be a driving frequency at which flicker is not visually recognized in the intermediate visual field area VR2, and the third driving frequency DF3 may be a driving frequency at which flicker is not visually recognized in the peripheral visual field area VR3.

[0057] According to one or more embodiments, output image data IMD2 may be generated by performing foveated rendering on input image data. In other words, input image data may be converted into output image data IMD2 by performing foveated rendering on the input image data. Foveated rendering may be a technique for reducing the resolution of an area other than an area where a user is gazing (e.g., directly gazing), so that the size of image data may be reduced when foveated rendering is used.

[0058] According to one or more embodiments, Figure 2 As shown in , the output image data IMD2 may include a gaze point region R1, a mixed region R2, and a peripheral region R3. The gaze point region R1 may be a region that a user gazes at (e.g., directly gazes at), the mixed region R2 may be located outside the gaze point region R1, and the peripheral region R3 may be located outside the mixed region R2. The gaze point region R1 may have a high resolution, the mixed region R2 may have a medium resolution, and the peripheral region R3 may have a low resolution. Through foveated rendering, the resolution of the mixed region R2 may be lower than the resolution of the gaze point region R1, and the resolution of the peripheral region R3 may be lower than the resolution of the mixed region R2.

[0059] The visual field tester 160 can measure the central visual field area VR1, the intermediate visual field area VR2 and the peripheral visual field area VR3 by testing the visual field of the user. Figure 3 As shown in , the visual field tester 160 can set the area including the user's gaze point GP as the central visual field area VR1, can set the area surrounding the central visual field area VR1 as the intermediate visual field area VR2, and can set the area other than the central visual field area VR1 and the intermediate visual field area VR2 (for example, the area other than the central visual field area VR1 and the intermediate visual field area VR2 in the entire visual field area VR of the user) as the peripheral visual field area VR3.

[0060] According to one or more embodiments, the visual field tester 160 may perform a visual field test on the left and right eyes of the user by using a dynamic visual field measurement scheme, and may measure a central visual field area VR1, an intermediate visual field area VR2, and a peripheral visual field area VR3 for each of the left and right eyes of the user through the result of the visual field test. The visual field tester 160 may store the central visual field area VR1, the intermediate visual field area VR2, and the peripheral visual field area VR3 of the user in a storage unit such as a memory.

[0061] According to one or more embodiments, the driving frequency calculator 150 may receive the central visual field area VR1 , the intermediate visual field area VR2 , and the peripheral visual field area VR3 generated by the visual field test from the outside In this case, the visual field tester 160 may be omitted.

[0062] The controller 140 may control the operation of the scan driver 120 and the operation of the data driver 130 based on the output image data IMD2 and based on the first to third driving frequencies DF1, DF2, and DF3. Figure 4As shown in FIG. 1 , in the display area DA of the display panel 110, the central visual field area VR1 may be driven at a first driving frequency DF1, the intermediate visual field area VR2 may be driven at a second driving frequency DF2, and the peripheral visual field area VR3 may be driven at a third driving frequency DF3. Therefore, flicker may not be visually recognized in the image displayed by the display device 100, and the image quality of the display device 100 may be improved. In addition, because the central visual field area VR1, the intermediate visual field area VR2, and the peripheral visual field area VR3 are driven at driving frequencies DF1, DF2, and DF3 that are independent of each other, respectively, the power consumption of the display device 100 may be reduced.

[0063] Figure 5 It is shown that the Figure 1 1 is a block diagram of a driving frequency calculator 150 in a display device 100. Figure 6 Is used to describe Figure 5 FIG. 1 is a view of an image divider 151 of a driving frequency calculator 150 . Figure 7 Is used to describe Figure 5 FIG. 1 is a view of the driving frequency calculator 150 and the spatial frequency calculator 152 . Figure 8 and Fig. 9 Is used to describe Figure 5 FIG. 1 is a view of the critical flicker frequency calculator 153 of the driving frequency calculator 150.

[0064] Reference Figure 5 The driving frequency calculator 150 may include an image divider 151 , a spatial frequency calculator 152 , a critical flicker frequency calculator 153 , and a driving frequency determiner 154 .

[0065] The image divider 151 may divide the output image data IMD2 into a central image IMG1, an intermediate image IMG2, and a peripheral image IMG3. Figure 6 As shown in , the central image IMG1, the intermediate image IMG2, and the peripheral image IMG3 may correspond to the central visual field area VR1, the intermediate visual field area VR2, and the peripheral visual field area VR3 of the user, respectively. The central visual field area VR1, the intermediate visual field area VR2, and the peripheral visual field area VR3 may vary for each user. Therefore, typically, the gaze point area R1, the mixed area R2, and the peripheral area R3 of the output image data IMD2 may not match the central image IMG1, the intermediate image IMG2, and the peripheral image IMG3, respectively. However, for ease of description, the central image IMG1, the intermediate image IMG2, and the peripheral image IMG3 are described below as matching the gaze point area R1, the mixed area R2, and the peripheral area R3 of the output image data IMD2, respectively.

[0066] The spatial frequency calculator 152 may calculate a first spatial frequency CPD1 of the central image IMG1, a second spatial frequency CPD2 of the intermediate image IMG2, and a third spatial frequency CPD3 of the peripheral image IMG3. The spatial frequency may refer to the number of cycles of data included within a 1 degree field of view and may be referred to as cycles per degree (CPD).

[0067] According to one or more embodiments, the first spatial frequency CPD1, the second spatial frequency CPD2, and the third spatial frequency CPD3 may be calculated by performing Fast Fourier Transform (FFT) on the central image IMG1, the intermediate image IMG2, and the peripheral image IMG3, respectively. Figure 7 As shown in , a fast Fourier transform may be performed on the central image IMG1, the intermediate image IMG2, and the peripheral image IMG3 to obtain first Fourier data FFT1, second Fourier data FFT2, and third Fourier data FFT3 corresponding to the central image IMG1, the intermediate image IMG2, and the peripheral image IMG3, respectively. The first Fourier data FFT1, the second Fourier data FFT2, and the third Fourier data FFT3 may be analyzed to calculate a first spatial frequency CPD1, a second spatial frequency CPD2, and a third spatial frequency CPD3.

[0068] As the resolution of the image decreases, the spatial frequency of the image may gradually decrease. Because the resolution decreases in the direction from the gaze point region R1 to the mixed region R2 and then to the peripheral region R3, the resolution of the intermediate image IMG2 may be lower than the resolution of the central image IMG1, and the resolution of the peripheral image IMG3 may be lower than the resolution of the intermediate image IMG2. Therefore, the second spatial frequency CPD2 may be lower than the first spatial frequency CPD1, and the third spatial frequency CPD3 may be lower than the second spatial frequency CPD2.

[0069] The critical flicker frequency calculator 153 may calculate a first critical flicker frequency CFF1 of the central visual field area VR1, a second critical flicker frequency CFF2 of the intermediate visual field area VR2, and a third critical flicker frequency CFF3 of the peripheral visual field area VR3 based on the first to third spatial frequencies CPD1, CPD2, and CPD3 and the viewing angles of the central visual field area VR1, the intermediate visual field area VR2, and the peripheral visual field area VR3. The critical flicker frequency (CFF) may refer to a minimum frequency at which a user may not recognize flicker. In other words, when the driving frequency of the visual field area is greater than or equal to the critical flicker frequency of the visual field area, the user may not recognize flicker in the visual field area.

[0070] Figure 8The critical flicker frequency CFF[0.1] according to the viewing angle when the spatial frequency CPD is 0.1, the critical flicker frequency CFF[1.2] according to the viewing angle when the spatial frequency CPD is 1.2, and the critical flicker frequency CFF[2.0] according to the viewing angle when the spatial frequency CPD is 2.0 are shown.

[0071] Reference Figure 8 , the critical flicker frequency CFF may vary according to the spatial frequency CPD and the viewing angle. Even when the spatial frequency CPD is the same, the critical flicker frequency CFF may vary when the viewing angle varies, and even when the viewing angle is the same, the critical flicker frequency CFF may vary when the spatial frequency CPD varies. According to one or more embodiments, the viewing angle of the central field of view area VR1 may be approximately 0 degrees to approximately 15 degrees, the viewing angle of the intermediate field of view area VR2 may be approximately 15 degrees to approximately 45 degrees, and the viewing angle of the peripheral field of view area VR3 may be approximately 45 degrees or greater. In this case, when the spatial frequency CPD is 0.1, the second critical flicker frequency CFF2 may be greater than the first critical flicker frequency CFF1, and the third critical flicker frequency CFF3 may be less than the second critical flicker frequency CFF2.

[0072] Fig. 9 is a graph showing a temporal contrast sensitivity function (TCSF) of each of the central visual field area VR1 , the intermediate visual field area VR2 , and the peripheral visual field area VR3 .

[0073] Reference Fig. 9 According to one or more embodiments, the first to third critical flicker frequencies CFF1, CFF2, and CFF3 may be calculated by using a time contrast sensitivity function. The time contrast sensitivity function may represent the sensitivity of flicker in a field of view area relative to the frequency of the field of view area. In the time contrast sensitivity function, the minimum frequency at which the sensitivity becomes approximately 0 may be a critical flicker frequency. Therefore, the minimum frequency at which the sensitivity in the time contrast sensitivity function in the central field of view area VR1 becomes approximately 0 may be calculated as the first critical flicker frequency CFF1, the minimum frequency at which the sensitivity in the time contrast sensitivity function in the intermediate field of view area VR2 becomes approximately 0 may be calculated as the second critical flicker frequency CFF2, and the minimum frequency at which the sensitivity in the time contrast sensitivity function in the peripheral field of view area VR3 becomes approximately 0 may be calculated as the third critical flicker frequency CFF3.

[0074] The driving frequency determiner 154 may determine a first driving frequency DF1 of the central viewing area VR1 , a second driving frequency DF2 of the intermediate viewing area VR2 , and a third driving frequency DF3 of the peripheral viewing area VR3 based on the first to third critical flicker frequencies CFF1 , CFF2 , and CFF3 .

[0075] According to one or more embodiments, the first driving frequency DF1, the second driving frequency DF2, and the third driving frequency DF3 may be greater than or equal to the first critical flicker frequency CFF1, the second critical flicker frequency CFF2, and the third critical flicker frequency CFF3, respectively. Because the driving frequency is greater than or equal to the critical flicker frequency in each of the central visual field area VR1, the intermediate visual field area VR2, and the peripheral visual field area VR3, flicker may not be visually recognized in the central visual field area VR1, the intermediate visual field area VR2, and the peripheral visual field area VR3.

[0076] Fig.10 is a block diagram illustrating a display device 101 according to one or more embodiments of the present disclosure.

[0077] Reference Fig.10 , the display device 101 may include a display panel 110, a scan driver 120, a data driver 130, a controller 140, a driving frequency calculator 150, a visual field tester 160, and a renderer 170. In addition to the display device 101 further including the renderer 170, reference will be made to Fig.10 The display device 101 described can be used with reference to Figure 1 The display devices 100 described are substantially the same or similar. Therefore, redundant descriptions of the components will be omitted.

[0078] The renderer 170 may convert the input image data IMD1 into output image data IMD2 by performing foveated rendering on the input image data IMD1. The renderer 170 may convert the externally provided input image data IMD1 into output image data IMD2, and may provide the output image data IMD2 to the controller 140 and the driving frequency calculator 150.

[0079] Fig.11 is a flowchart illustrating a method for driving a display device according to one or more embodiments of the present disclosure.

[0080] Reference Figure 1 and Fig.11 According to the method for driving the display device 100, the visual field tester 160 may measure the central visual field area VR1, the intermediate visual field area VR2, and the peripheral visual field area VR3 by testing the visual field of the user (S110). Figure 3As shown in , the visual field tester 160 can set the area including the user's gaze point GP as the central visual field area VR1, can set the area surrounding the central visual field area VR1 as the intermediate visual field area VR2, and can set the area other than the central visual field area VR1 and the intermediate visual field area VR2 (for example, the area other than the central visual field area VR1 and the intermediate visual field area VR2 in the entire visual field area VR of the user) as the peripheral visual field area VR3.

[0081] Reference Fig.10 and Fig.11 , the renderer 170 may convert the input image data IMD1 into output image data IMD2 by performing foveated rendering on the input image data IMD1 ( S120 ). When the display apparatus 100 receives output image data IMD2 provided externally, the operation S120 of converting the input image data IMD1 into output image data IMD2 may be omitted.

[0082] Reference Figure 5 and Fig.11 , the image divider 151 of the driving frequency calculator 150 may divide the output image data IMD2 into a central image IMG1, an intermediate image IMG2, and a peripheral image IMG3 (S130). Figure 6 As shown in , the central image IMG1 , the intermediate image IMG2 , and the peripheral image IMG3 may correspond to the central visual field area VR1 , the intermediate visual field area VR2 , and the peripheral visual field area VR3 of the user, respectively.

[0083] The spatial frequency calculator 152 of the driving frequency calculator 150 may calculate a first spatial frequency CPD1 of the central image IMG1 , a second spatial frequency CPD2 of the intermediate image IMG2 , and a third spatial frequency CPD3 of the peripheral image IMG3 ( S140 ).

[0084] According to one or more embodiments, the first spatial frequency CPD1, the second spatial frequency CPD2, and the third spatial frequency CPD3 may be calculated by performing Fast Fourier Transform (FFT) on the central image IMG1, the intermediate image IMG2, and the peripheral image IMG3, respectively. Figure 7As shown in , a fast Fourier transform may be performed on the central image IMG1, the intermediate image IMG2, and the peripheral image IMG3 to obtain first Fourier data FFT1, second Fourier data FFT2, and third Fourier data FFT3 corresponding to the central image IMG1, the intermediate image IMG2, and the peripheral image IMG3, respectively. The first Fourier data FFT1, the second Fourier data FFT2, and the third Fourier data FFT3 may be analyzed to calculate a first spatial frequency CPD1, a second spatial frequency CPD2, and a third spatial frequency CPD3. According to one or more embodiments, the second spatial frequency CPD2 may be less than the first spatial frequency CPD1, and the third spatial frequency CPD3 may be less than the second spatial frequency CPD2.

[0085] The critical flicker frequency calculator 153 of the driving frequency calculator 150 can calculate a first critical flicker frequency CFF1 of the central visual field area VR1, a second critical flicker frequency CFF2 of the intermediate visual field area VR2, and a third critical flicker frequency CFF3 of the peripheral visual field area VR3 based on the first to third spatial frequencies CPD1, CPD2, and CPD3 and based on the viewing angles of the central visual field area VR1, the intermediate visual field area VR2, and the peripheral visual field area VR3 (S150).

[0086] According to one or more embodiments, the first to third critical flicker frequencies CFF1, CFF2, and CFF3 may be calculated by using a time contrast sensitivity function. Fig. 9 As shown in, the minimum frequency at which the sensitivity in the time contrast sensitivity function in the central visual field area VR1 becomes 0 can be calculated as the first critical flicker frequency CFF1, the minimum frequency at which the sensitivity in the time contrast sensitivity function in the intermediate visual field area VR2 becomes 0 can be calculated as the second critical flicker frequency CFF2, and the minimum frequency at which the sensitivity in the time contrast sensitivity function in the peripheral visual field area VR3 becomes 0 can be calculated as the third critical flicker frequency CFF3.

[0087] The driving frequency determiner 154 of the driving frequency calculator 150 may determine a first driving frequency DF1 of the central viewing area VR1, a second driving frequency DF2 of the intermediate viewing area VR2, and a third driving frequency DF3 of the peripheral viewing area VR3 based on the first to third critical flicker frequencies CFF1, CFF2, and CFF3 (S160).

[0088] According to one or more embodiments, the first driving frequency DF1 , the second driving frequency DF2 , and the third driving frequency DF3 may be greater than or equal to the first critical flicker frequency CFF1 , the second critical flicker frequency CFF2 , and the third critical flicker frequency CFF3 , respectively.

[0089] Reference Figure 1 and Fig.11 , the display panel 110 may display an image based on the output image data IMD2 and the first to third driving frequencies DF1, DF2, and DF3 (S170). Since the driving frequency is greater than or equal to the critical flicker frequency in each of the central visual field area VR1, the intermediate visual field area VR2, and the peripheral visual field area VR3, flicker may not be visually recognized in the central visual field area VR1, the intermediate visual field area VR2, and the peripheral visual field area VR3, and the image quality of the display device 100 may be improved. In addition, since the first to third driving frequencies DF1, DF2, and DF3 are determined independently of each other, the power consumption of the display device 100 may be reduced.

[0090] Fig.12 1 is a block diagram illustrating a head mounted display device 1000 according to one or more embodiments of the present disclosure.

[0091] Reference Fig.12 , a head mounted display (HMD) device 1000 may include a processor 1010, a memory device 1020, an input / output (I / O) device 1030, a power supply 1040, a sensing device 1050, and a display device 1060. The components of the head mounted display device 1000 are not limited to Fig.12 The components shown in FIG. 1 and the head mounted display device 1000 may have Fig.12 More or fewer components than shown in the .

[0092] The processor 1010 may perform specific calculations or tasks. The processor 1010 may control the overall operation of the head mounted display device 1000. According to one or more embodiments, the processor 1010 may be a microprocessor, a central processing unit (CPU), etc. The processor 1010 may be connected to other components through an address bus, a control bus, a data bus, etc. According to one or more embodiments, the processor 1010 may also be connected to an expansion bus such as a peripheral component interconnect (PCI) bus.

[0093] The processor 1010 can process the input image data (for example, Fig.10 IMD1) into output image data (e.g., Figure 1 According to one or more embodiments, the processor 1010 may generate output image data IMD2 by performing foveated rendering on input image data.

[0094] The memory device 1020 may store data suitable for the operation of the head mounted display device 1000. For example, the memory device 1020 may include: a non-volatile memory device (such as an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a flash memory, a phase change random access memory (PRAM), a resistive random access memory (RRAM), a nano floating gate memory (NFGM), a polymer random access memory (PoRAM), a magnetic random access memory (MRAM), or a ferroelectric random access memory (FRAM)); and / or a volatile memory device (such as a dynamic random access memory (DRAM), a static random access memory (SRAM), or a mobile DRAM).

[0095] The I / O device 1030 may include: input devices, including a camera or image input device configured to input image signals, a microphone or audio input device configured to input audio signals, a user input device configured to receive information from a user (for example, a touch key, a push key, a joystick, a wheel, etc.), etc.; and output devices, including an audio output device, a tactile module, an optical output device, etc. configured to generate outputs related to visual sensations, auditory sensations, tactile sensations, etc.

[0096] The power supply 1040 may supply power suitable for the operation of the head mounted display device 1000. The power supply 1040 may receive external power and internal power, and may supply power to each of the components included in the head mounted display device 1000. The power supply 1040 may be implemented as a built-in battery or a replaceable battery.

[0097] The sensing device 1050 may include at least one sensor configured to sense information about the peripheral environment of the head mounted display device 1000, information about the user of the head mounted display device 1000, etc. For example, the sensing device 1050 may include a velocity sensor, an acceleration sensor, a gravity sensor, an illumination sensor, a motion sensor, a fingerprint recognition sensor, an optical sensor, an ultrasonic sensor, a thermal sensor, etc.

[0098] The display device 1060 may be connected to other components via a bus or other communication link. The display device 1060 may display information processed by the head mounted display device 1000. The display device 1060 may correspond to Figure 1 The display device 100 or Fig.10 A display device 101 is provided.

[0099] Fig.13 It shows the realization Fig.12 000 .

[0100] Reference Fig.13, the head-mounted display device 1000 may include a display device 1060, a housing 1070, and a mounting component 1080. The head-mounted display device 1000 may be worn on the user's head to provide image information to the user. The display device 1060 may display an image based on the image data. The display device 1060 may provide an image to each of the left eye and the right eye of the user. The left-eye image corresponding to the user's left eye and the right-eye image corresponding to the user's right eye may be the same as or different from each other. The head-mounted display device 1000 may provide a two-dimensional image, a three-dimensional image, a virtual reality (VR) image, a 360-degree panoramic image, and the like through the display device 1060.

[0101] The display device 1060 may be a liquid crystal display device, an organic light emitting display device, an inorganic light emitting display device, a quantum dot light emitting display device, etc. The display device 1060 may be installed in the housing 1070 or may be coupled to the housing 1070. The display device 1060 may receive instructions through an interface unit provided in the housing 1070, etc.

[0102] The housing 1070 may be located in front of the user's eyes. The housing 1070 may store components configured to operate the head-mounted display device 1000. In addition, a wireless communication unit, an interface unit, and the like may be located in the housing 1070. The wireless communication unit may perform wireless communication with an external terminal to receive an image signal from the external terminal. For example, the wireless communication unit may communicate with an external terminal by using Bluetooth, radio frequency identification (RFID), infrared data association (IrDA), ZigBee, near field communication (NFC), wireless fidelity (Wi-Fi), ultra-wideband (UWB), and the like. The interface unit may connect the head-mounted display device 1000 to an external device. For example, the interface unit may include at least one of a wired / wireless headset port, an external charger port, a wired / wireless data port, a memory card port, a port configured to connect a device provided with an identification module, an audio I / O port, a video I / O port, or a headphone port.

[0103] The mounting member 1080 may be connected to the housing 1070 to fix the head mounted display device 1000 to the user's head. For example, the mounting member 1080 may be implemented as an elastic band, a hoop, or the like.

[0104] The display device according to the embodiment may be applied to a display device included in a head mounted display (HMD) device, a computer, a notebook computer, a mobile phone, a smart phone, a smart tablet, a PMP, a PDA, an MP3 player, and the like.

[0105] Although the display device, the method for driving the display device, and the head-mounted display device according to the embodiments have been described with reference to the accompanying drawings, the embodiments shown are examples and can be modified and changed by ordinary technicians in the relevant technical field without departing from the technical spirit described in the claims and the functional equivalents to be included therein.

Claims

1. A display device, comprising: a driving frequency calculator configured to: divide the output image data into a central image, an intermediate image, and a peripheral image corresponding to a central visual field area, an intermediate visual field area, and a peripheral visual field area, respectively; Calculating spatial frequencies of the central image, the intermediate image, and the peripheral image; calculating critical flicker frequencies of the central visual field area, the intermediate visual field area, and the peripheral visual field area based on the spatial frequencies and based on the viewing angles of the central visual field area, the intermediate visual field area, and the peripheral visual field area; and determining driving frequencies of the central visual field area, the intermediate visual field area, and the peripheral visual field area based on the critical flicker frequency; as well as The display panel is configured to display an image based on the output image data and based on the driving frequency.

2. The display device according to claim 1, wherein: The output image data includes input image data on which foveated rendering is performed. 3 . The display device according to claim 1 , further comprising a visual field tester configured to measure the central visual field area, the intermediate visual field area, and the peripheral visual field area through a visual field test.

4. The display device according to claim 3, wherein: The visual field tester is configured to: Setting the area including the fixation point as the central visual field area; Setting the area surrounding the central visual area as the intermediate visual area; as well as An area of ​​the entire visual field area except the central visual field area and the intermediate visual field area is set as the peripheral visual field area.

5. The display device according to claim 1, wherein: The spatial frequencies are calculated by performing a Fast Fourier Transform on the central image, the intermediate images, and the peripheral images.

6. The display device according to claim 1, wherein: The spatial frequency of the peripheral image is smaller than the spatial frequency of the central image.

7. The display device according to claim 1, wherein: The driving frequency of the central field of view area, the driving frequency of the intermediate field of view area, and the driving frequency of the peripheral field of view area are respectively greater than or equal to the critical flicker frequency of the central field of view area, the critical flicker frequency of the intermediate field of view area, and the critical flicker frequency of the peripheral field of view area. 8 . The display device according to claim 1 , further comprising a renderer configured to convert the input image data into the output image data by performing foveated rendering on the input image data.

9. A method for driving a display device, the method comprising: The output image data is divided into a central image, an intermediate image and a peripheral image corresponding to a central visual field area, an intermediate visual field area and a peripheral visual field area respectively; calculating the spatial frequencies of the central image, the intermediate images and the peripheral images; Calculating critical flicker frequencies of the central visual field area, the intermediate visual field area, and the peripheral visual field area based on the spatial frequency and based on the viewing angles of the central visual field area, the intermediate visual field area, and the peripheral visual field area; Determining driving frequencies of the central visual field area, the intermediate visual field area, and the peripheral visual field area based on the critical flicker frequency; as well as An image is displayed based on the output image data and based on the driving frequency.

10. A head-mounted display device, comprising: a processor configured to convert input image data into output image data; as well as A display device configured to display an image based on the output image data, and comprising: a driving frequency calculator configured to: divide the output image data into a central image, an intermediate image, and a peripheral image corresponding to a central field of view area, an intermediate field of view area, and a peripheral field of view area, respectively; calculate spatial frequencies of the central image, the intermediate image, and the peripheral image; calculate critical flicker frequencies of the central field of view area, the intermediate field of view area, and the peripheral field of view area based on the spatial frequencies and based on viewing angles of the central field of view area, the intermediate field of view area, and the peripheral field of view area; and determine driving frequencies of the central field of view area, the intermediate field of view area, and the peripheral field of view area based on the critical flicker frequencies; and The display panel is configured to display the image based on the output image data and based on the driving frequency.

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