Patent Publication Number: US-2022217325-A1

Title: Electronic device for displaying content and method of operation thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a Continuation based on and claims priority under 35 U.S.C. § 120 to PCT International Application No. PCT/KR2021/019040, which was filed on Dec. 15, 2021, and claims priority to Korean Patent Application No. 10-2021-0001015, filed on Jan. 5, 2021, in the Korean Intellectual Property Office, the disclosure of which are incorporated by reference herein their entirety. 
    
    
     BACKGROUND 
     One or more embodiments disclosed in this specification generally relate to an electronic device for displaying content and an operating method thereof 
     Virtual reality (VR) is a technology that generates and displays a virtual environment similar to a real environment, one where the user can interact with virtual objects. 
     Augmented reality (AR) is a technology that synthesizes virtual objects with the real environment and then displays the synthesized result. 
     An electronic device including a head mounted display (HMD) may display VR content or AR content in front of a user&#39;s eyes such that the user feels as if he/she is present in VR or AR environment. The electronic device may recognize an external environment viewed by the user and may provide the AR content reflecting the recognized result. The electronic device including the HMD may be implemented, for example, as a pair of glasses. 
     SUMMARY 
     A conventional VR or AR device provides high realism and immersion by implementing 3D stereoscopic effects. On the other hand, conventional VR devices or AR devices may cause issue for users. 
     For example, while users of VR devices or AR devices view content or after the users view content, the users may feel eye fatigue and headache. In severe cases, the users may feel visual fatigue enough to cause pain. Visual fatigue is the most frequent symptom when the users employ VR devices or AR devices, and urgently needs to be addressed. 
     For example, factors causing the visual fatigue may include the display, visual content, viewer characteristics, or viewing environment. For example, as the resolution or luminance of a display increases, eye fatigue may increase. Accordingly, the eye fatigue may be reduced by lowering the resolution or brightness of the display. 
     The conventional VR or AR device may increase the user&#39;s eye fatigue by uniformly displaying content without taking into account the user&#39;s eye fatigue. 
     According to an embodiment disclosed in the specification, an electronic device may include a camera module, a display that displays AR content or VR content including at least one object, at least one processor operatively connected to the camera module and the display, and a memory operatively connected to the at least one processor and storing the AR content or VR content. The memory may store one or more instructions that, when executed, cause the at least one processor to obtain eye tracking data by using the camera module, to determine an eye fatigue level based on the eye tracking data, and to select one mode between a first mode for changing a setting of the display and a second mode for changing both the setting of the display and an output setting of the AR content or VR content, depending on the eye fatigue level. 
     Furthermore, according to an embodiment disclosed in the specification, a method for operating an electronic device for displaying content may include obtaining eye tracking data by using a camera module, determining an eye fatigue level based on the eye tracking data, and selecting one mode between a first mode for changing a setting of a display and a second mode for changing both the setting of the display and an output setting of the content, depending on the eye fatigue level. 
     Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of certain embodiments of the present disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a block diagram of an electronic device in a network environment, according to an embodiment. 
         FIG. 2  is a diagram illustrating components of an electronic device, according to an embodiment. 
         FIG. 3  is a block diagram of an electronic device, according to an embodiment. 
         FIG. 4  is a block diagram of the electronic device, according to an embodiment. 
         FIG. 5  is a flowchart illustrating an operating method of an electronic device, according to an embodiment. 
         FIG. 6  is a flowchart illustrating an operating method of an electronic device, according to an embodiment. 
         FIG. 7  is a flowchart illustrating an operating method of an electronic device, according to an embodiment. 
         FIG. 8  is a diagram illustrating an example of changing a display setting of an electronic device, according to an embodiment. 
         FIG. 9  is a diagram illustrating an example of changing an output setting of content of an electronic device, according to an embodiment. 
         FIG. 10  is a diagram for describing an operation of changing an FOV of an electronic device, according to an embodiment. 
         FIG. 11  is a diagram illustrating a screen displayed on a display as an electronic device changes a FOV, according to an embodiment. 
         FIG. 12  is a flowchart illustrating an operating method of an electronic device, according to an embodiment. 
     
    
    
     With regard to description of drawings, the same or similar components will be marked by the same or similar reference signs. 
     DETAILED DESCRIPTION 
     According to certain embodiments disclosed in the specification, it is possible to provide an electronic device that reduces the user&#39;s eye fatigue by changing at least one of a setting of a display or an output setting of content based on the user&#39;s eye fatigue, and an operating method thereof. 
     Besides, various other effects directly or indirectly understood through the specification may be provided. 
       FIG. 1  is a block diagram illustrating an electronic device  101  in a network environment  100  according to various embodiments. Referring to  FIG. 1 , the electronic device  101  in the network environment  100  may communicate with an electronic device  102  via a first network  198  (e.g., a short-range wireless communication network), or at least one of an electronic device  104  or a server  108  via a second network  199  (e.g., a long-range wireless communication network). According to an embodiment, the electronic device  101  may communicate with the electronic device  104  via the server  108 . According to an embodiment, the electronic device  101  may include a processor  120 , memory  130 , an input module  150 , a sound output module  155 , a display module  160 , an audio module  170 , a sensor module  176 , an interface  177 , a connecting terminal  178 , a haptic module  179 , a camera module  180 , a power management module  188 , a battery  189 , a communication module  190 , a subscriber identification module (SIM)  196 , or an antenna module  197 . In some embodiments, at least one of the components (e.g., the connecting terminal  178 ) may be omitted from the electronic device  101 , or one or more other components may be added in the electronic device  101 . In some embodiments, some of the components (e.g., the sensor module  176 , the camera module  180 , or the antenna module  197 ) may be implemented as a single component (e.g., the display module  160 ). 
     The processor  120  may execute, for example, software (e.g., a program  140 ) to control at least one other component (e.g., a hardware or software component) of the electronic device  101  coupled with the processor  120 , and may perform various data processing or computation. According to one embodiment, as at least part of the data processing or computation, the processor  120  may store a command or data received from another component (e.g., the sensor module  176  or the communication module  190 ) in volatile memory  132 , process the command or the data stored in the volatile memory  132 , and store resulting data in non-volatile memory  134 . According to an embodiment, the processor  120  may include a main processor  121  (e.g., a central processing unit (CPU) or an application processor (AP)), or an auxiliary processor  123  (e.g., a graphics processing unit (GPU), a neural processing unit (NPU), an image signal processor (ISP), a sensor hub processor, or a communication processor (CP)) that is operable independently from, or in conjunction with, the main processor  121 . For example, when the electronic device  101  includes the main processor  121  and the auxiliary processor  123 , the auxiliary processor  123  may be adapted to consume less power than the main processor  121 , or to be specific to a specified function. The auxiliary processor  123  may be implemented as separate from, or as part of the main processor  121 . 
     The auxiliary processor  123  may control at least some of functions or states related to at least one component (e.g., the display module  160 , the sensor module  176 , or the communication module  190 ) among the components of the electronic device  101 , instead of the main processor  121  while the main processor  121  is in an inactive (e.g., sleep) state, or together with the main processor  121  while the main processor  121  is in an active state (e.g., executing an application). According to an embodiment, the auxiliary processor  123  (e.g., an image signal processor or a communication processor) may be implemented as part of another component (e.g., the camera module  180  or the communication module  190 ) functionally related to the auxiliary processor  123 . According to an embodiment, the auxiliary processor  123  (e.g., the neural processing unit) may include a hardware structure specified for artificial intelligence model processing. An artificial intelligence model may be generated by machine learning. Such learning may be performed, e.g., by the electronic device  101  where the artificial intelligence is performed or via a separate server (e.g., the server  108 ). Learning algorithms may include, but are not limited to, e.g., supervised learning, unsupervised learning, semi-supervised learning, or reinforcement learning. The artificial intelligence model may include a plurality of artificial neural network layers. The artificial neural network may be a deep neural network (DNN), a convolutional neural network (CNN), a recurrent neural network (RNN), a restricted boltzmann machine (RBM), a deep belief network (DBN), a bidirectional recurrent deep neural network (BRDNN), deep Q-network or a combination of two or more thereof but is not limited thereto. The artificial intelligence model may, additionally or alternatively, include a software structure other than the hardware structure. 
     The memory  130  may store various data used by at least one component (e.g., the processor  120  or the sensor module  176 ) of the electronic device  101 . The various data may include, for example, software (e.g., the program  140 ) and input data or output data for a command related thereto. The memory  130  may include the volatile memory  132  or the non-volatile memory  134 . 
     The program  140  may be stored in the memory  130  as software, and may include, for example, an operating system (OS)  142 , middleware  144 , or an application  146 . 
     The input module  150  may receive a command or data to be used by another component (e.g., the processor  120 ) of the electronic device  101 , from the outside (e.g., a user) of the electronic device  101 . The input module  150  may include, for example, a microphone, a mouse, a keyboard, a key (e.g., a button), or a digital pen (e.g., a stylus pen). 
     The sound output module  155  may output sound signals to the outside of the electronic device  101 . The sound output module  155  may include, for example, a speaker or a receiver. The speaker may be used for general purposes, such as playing multimedia or playing record. The receiver may be used for receiving incoming calls. According to an embodiment, the receiver may be implemented as separate from, or as part of the speaker. 
     The display module  160  may visually provide information to the outside (e.g., a user) of the electronic device  101 . The display module  160  may include, for example, a display, a hologram device, or a projector and control circuitry to control a corresponding one of the display, hologram device, and projector. According to an embodiment, the display module  160  may include a touch sensor adapted to detect a touch, or a pressure sensor adapted to measure the intensity of force incurred by the touch. 
     The audio module  170  may convert a sound into an electrical signal and vice versa. According to an embodiment, the audio module  170  may obtain the sound via the input module  150 , or output the sound via the sound output module  155  or a headphone of an external electronic device (e.g., an electronic device  102 ) directly (e.g., wiredly) or wirelessly coupled with the electronic device  101 . 
     The sensor module  176  may detect an operational state (e.g., power or temperature) of the electronic device  101  or an environmental state (e.g., a state of a user) external to the electronic device  101 , and then generate an electrical signal or data value corresponding to the detected state. According to an embodiment, the sensor module  176  may include, for example, a gesture sensor, a gyro sensor, an atmospheric pressure sensor, a magnetic sensor, an acceleration sensor, a grip sensor, a proximity sensor, a color sensor, an infrared (IR) sensor, a biometric sensor, a temperature sensor, a humidity sensor, or an illuminance sensor. 
     The interface  177  may support one or more specified protocols to be used for the electronic device  101  to be coupled with the external electronic device (e.g., the electronic device  102 ) directly (e.g., wiredly) or wirelessly. According to an embodiment, the interface  177  may include, for example, a high definition multimedia interface (HDMI), a universal serial bus (USB) interface, a secure digital (SD) card interface, or an audio interface. 
     A connecting terminal  178  may include a connector via which the electronic device  101  may be physically connected with the external electronic device (e.g., the electronic device  102 ). According to an embodiment, the connecting terminal  178  may include, for example, a HDMI connector, a USB connector, a SD card connector, or an audio connector (e.g., a headphone connector). 
     The haptic module  179  may convert an electrical signal into a mechanical stimulus (e.g., a vibration or a movement) or electrical stimulus which may be recognized by a user via his tactile sensation or kinesthetic sensation. According to an embodiment, the haptic module  179  may include, for example, a motor, a piezoelectric element, or an electric stimulator. 
     The camera module  180  may capture a still image or moving images. According to an embodiment, the camera module  180  may include one or more lenses, image sensors, image signal processors, or flashes. 
     The power management module  188  may manage power supplied to the electronic device  101 . According to one embodiment, the power management module  188  may be implemented as at least part of, for example, a power management integrated circuit (PMIC). 
     The battery  189  may supply power to at least one component of the electronic device  101 . According to an embodiment, the battery  189  may include, for example, a primary cell which is not rechargeable, a secondary cell which is rechargeable, or a fuel cell. 
     The communication module  190  may support establishing a direct (e.g., wired) communication channel or a wireless communication channel between the electronic device  101  and the external electronic device (e.g., the electronic device  102 , the electronic device  104 , or the server  108 ) and performing communication via the established communication channel. The communication module  190  may include one or more communication processors that are operable independently from the processor  120  (e.g., the application processor (AP)) and supports a direct (e.g., wired) communication or a wireless communication. According to an embodiment, the communication module  190  may include a wireless communication module  192  (e.g., a cellular communication module, a short-range wireless communication module, or a global navigation satellite system (GNSS) communication module) or a wired communication module  194  (e.g., a local area network (LAN) communication module or a power line communication (PLC) module). A corresponding one of these communication modules may communicate with the external electronic device via the first network  198  (e.g., a short-range communication network, such as Bluetooth™, wireless-fidelity (Wi-Fi) direct, or infrared data association (IrDA)) or the second network  199  (e.g., a long-range communication network, such as a legacy cellular network, a 5G network, a next-generation communication network, the Internet, or a computer network (e.g., LAN or wide area network (WAN)). These various types of communication modules may be implemented as a single component (e.g., a single chip), or may be implemented as multi components (e.g., multi chips) separate from each other. The wireless communication module  192  may identify and authenticate the electronic device  101  in a communication network, such as the first network  198  or the second network  199 , using subscriber information (e.g., international mobile subscriber identity (IMSI)) stored in the subscriber identification module  196 . 
     The wireless communication module  192  may support a 5G network, after a 4G network, and next-generation communication technology, e.g., new radio (NR) access technology. The NR access technology may support enhanced mobile broadband (eMBB), massive machine type communications (mMTC), or ultra-reliable and low-latency communications (URLLC). The wireless communication module  192  may support a high-frequency band (e.g., the mmWave band) to achieve, e.g., a high data transmission rate. The wireless communication module  192  may support various technologies for securing performance on a high-frequency band, such as, e.g., beamforming, massive multiple-input and multiple-output (massive MIMO), full dimensional MIMO (FD-MIMO), array antenna, analog beam-forming, or large scale antenna. The wireless communication module  192  may support various requirements specified in the electronic device  101 , an external electronic device (e.g., the electronic device  104 ), or a network system (e.g., the second network  199 ). According to an embodiment, the wireless communication module  192  may support a peak data rate (e.g., 20 Gbps or more) for implementing eMBB, loss coverage (e.g., 164 dB or less) for implementing mMTC, or U-plane latency (e.g., 0.5 ms or less for each of downlink (DL) and uplink (UL), or a round trip of lms or less) for implementing URLLC. 
     The antenna module  197  may transmit or receive a signal or power to or from the outside (e.g., the external electronic device) of the electronic device  101 . According to an embodiment, the antenna module  197  may include an antenna including a radiating element composed of a conductive material or a conductive pattern formed in or on a substrate (e.g., a printed circuit board (PCB)). According to an embodiment, the antenna module  197  may include a plurality of antennas (e.g., array antennas). In such a case, at least one antenna appropriate for a communication scheme used in the communication network, such as the first network  198  or the second network  199 , may be selected, for example, by the communication module  190  (e.g., the wireless communication module  192 ) from the plurality of antennas. The signal or the power may then be transmitted or received between the communication module  190  and the external electronic device via the selected at least one antenna. According to an embodiment, another component (e.g., a radio frequency integrated circuit (RFIC)) other than the radiating element may be additionally formed as part of the antenna module  197 . 
     According to various embodiments, the antenna module  197  may form an mmWave antenna module. According to an embodiment, the mmWave antenna module may include a printed circuit board, a RFIC disposed on a first surface (e.g., the bottom surface) of the printed circuit board, or adjacent to the first surface and capable of supporting a designated high-frequency band (e.g., the mmWave band), and a plurality of antennas (e.g., array antennas) disposed on a second surface (e.g., the top or a side surface) of the printed circuit board, or adjacent to the second surface and capable of transmitting or receiving signals of the designated high-frequency band. 
     At least some of the above-described components may be coupled mutually and communicate signals (e.g., commands or data) therebetween via an inter-peripheral communication scheme (e.g., a bus, general purpose input and output (GPIO), serial peripheral interface (SPI), or mobile industry processor interface (MIPI)). 
     According to an embodiment, commands or data may be transmitted or received between the electronic device  101  and the external electronic device  104  via the server  108  coupled with the second network  199 . Each of the electronic devices  102  or  104  may be a device of a same type as, or a different type, from the electronic device  101 . According to an embodiment, all or some of operations to be executed at the electronic device  101  may be executed at one or more of the external electronic devices  102 ,  104 , or  108 . For example, if the electronic device  101  should perform a function or a service automatically, or in response to a request from a user or another device, the electronic device  101 , instead of, or in addition to, executing the function or the service, may request the one or more external electronic devices to perform at least part of the function or the service. The one or more external electronic devices receiving the request may perform the at least part of the function or the service requested, or an additional function or an additional service related to the request, and transfer an outcome of the performing to the electronic device  101 . The electronic device  101  may provide the outcome, with or without further processing of the outcome, as at least part of a reply to the request. To that end, a cloud computing, distributed computing, mobile edge computing (MEC), or client-server computing technology may be used, for example. The electronic device  101  may provide ultra low-latency services using, e.g., distributed computing or mobile edge computing. In another embodiment, the external electronic device  104  may include an intemet-of-things (IoT) device. The server  108  may be an intelligent server using machine learning and/or a neural network. According to an embodiment, the external electronic device  104  or the server  108  may be included in the second network  199 . The electronic device  101  may be applied to intelligent services (e.g., smart home, smart city, smart car, or healthcare) based on 5G communication technology or IoT-related technology. 
     Hereinafter, structure and components of an electronic device according to an embodiment will be described with reference to  FIG. 2 . 
       FIG. 2  is a diagram  200  illustrating components of an electronic device  201 , according to an embodiment. According to an embodiment, the electronic device  201  may be worn on the user&#39;s head. For example, the electronic device  201  may be a pair of glasses, but is not limited thereto. According to an embodiment, the electronic device  201  as a pair of glasses may include a frame  203  formed along an edge of a display positioned to face the user&#39;s eyes when the user wears the electronic device  201 , and a temple (e.g., a first temple member  205  and a second temple member  207 ) hung on the user&#39;s ear and connected to the frame  203  so as to place the frame  203  in front of the user&#39;s eyes. According to an embodiment, the temple may include a hinge (e.g., a first hinge  261  and a second hinge  263 ) connecting the temple and the frame  203 . According to an embodiment, the frame  203  may include a first portion surrounding the first display  211  and a second portion surrounding the second display  213 . According to an embodiment, the frame  203  may include a bridge  209  connecting the first portion and the second portion. According to an embodiment, there may be a plurality of temples. For example, two temples may be connected to the first portion and the second portion, respectively. For example, the first portion may be connected to the first temple member  205  by the first hinge  261 . The second portion may be connected to the second temple member  207  by the second hinge  263 . The first temple member  205  and the second temple member  207  may be folded to overlap the frame  203  by the first hinge  261  and the second hinge  263 . 
     Referring to  FIG. 2 , the electronic device  201  according to an embodiment may include a display (e.g., the first display  211  and the second display  213 ) (e.g., the display module  160  of  FIG. 1 ), a transparent member (e.g., a first transparent member  215  and a second transparent member  217 ), a waveguide (e.g., a first waveguide  225  and a second waveguide  227 ), an input optical member (e.g., a first input optical member  221  and a second input optical member  223 ), a camera module (e.g., a first camera  231 , a second camera  233 , a third camera  235 , a fourth camera  237 , and a fifth camera  239 ) (e.g., the camera module  180  of  FIG. 1 ), an illumination (e.g., a first light emitting diode (LED)  241  and a second LED  243 ), a printed circuit board (PCB) (e.g., a first PCB  251  and a second PCB  253 ), a hinge (e.g., the first hinge  261  and the second hinge  263 ), a microphone (e.g., a first microphone  271 , a second microphone  273 , and a third microphone  275 ) (e.g., the input module  150  of  FIG. 1 ), a speaker (e.g., a first speaker  281  and a second speaker  283 ) (e.g., the sound output module  155  of  FIG. 1 ), and a battery (e.g., a first battery  291  and a second battery  293 ) (e.g., the battery  189  of  FIG. 1 ). 
     The display according to an embodiment may include the first display  211  and the second display  213 . For example, the display may include a liquid crystal display (LCD), a digital mirror device (DMD), a liquid crystal on silicon (LCoS) device, and an organic light emitting diode (OLED), or a micro light emitting diode (micro LED). 
     According to an embodiment, when the display is composed of one of LCD, DMD or LCoS, the electronic device  201  may include a backlight that emits light to a screen display area of a display. 
     According to an embodiment, when the display is composed of OLED or micro LED, the pixels of the display may generate light by themselves, and thus the electronic device  201  may provide the user with a virtual image having a specific quality or higher because a separate backlight is not needed. According to an embodiment, when the display is composed of OLED or micro LED, the separate backlight is unnecessary, and thus the weight of electronic device  201  may be reduced. 
     According to an embodiment, the transparent member may include the first transparent member  215  and the second transparent member  217 . For example, the transparent member may be formed of a glass plate, a plastic plate, or a polymer. According to an embodiment, the transparent member may be made transparent or translucent. According to an embodiment, the first transparent member  215  may be arranged to face the user&#39;s right eye. The second transparent member  217  may be arranged to face the user&#39;s left eye. 
     According to an embodiment, the electronic device  201  may be positioned at a location facing the user&#39;s right and left eyes. The electronic device  201  may include a transparent display, and may implement a screen display area on the display. 
     According to an embodiment, the waveguide may include the first waveguide  225  and the second waveguide  227 . According to an embodiment, the waveguide may deliver the light generated by the display (e.g., the first display  211  and/or the second display  213 ) to the user&#39;s eyes. For example, the first waveguide  225  may deliver the light generated by the first display  211  to the user&#39;s right eye, and the second waveguide  227  may deliver the light generated by the second display  213  to the user&#39;s left eye. For example, the waveguide may be made of glass, plastic or polymer, and may include a nanopattem (e.g., a grating structure having a polygonal or curved shape) formed therein or on one surface. According to an embodiment, light incident to one end of the waveguide may be propagated inside the waveguide by a nanopattem and may be provided to the user. For example, the waveguide formed of a free-form prism may provide the incident light to the user through a reflection mirror. 
     According to an embodiment, the waveguide may include at least one of at least one diffractive element (e.g., a diffractive optical element (DOE) or a holographic optical element (HOE)) or a reflective element (e.g., a reflective mirror). The waveguide may guide the display light emitted from an illumination to the user&#39;s eyes by using the at least one diffractive element or the reflective element. For example, the diffractive element may include an input optical member (e.g., the first input optical member  221  and the second input optical member  223 ) and/or an output optical member (not shown). The first input optical member  221  and/or the second input optical member  223  may be referred to as an “input grating area”. The output optical member (not shown) may be referred to as an “output grating area”. The input grating area may diffract or reflect light output from a light source (e.g., a micro LED) to deliver the light to a transparent member (e.g., the first transparent member  215  and/or the second transparent member  217 ) of a screen display unit. The output grating area may diffract or reflect the light delivered to the transparent member (e.g., the first transparent member  215  and/or the second transparent member  217 ) of the waveguide in a direction of the user&#39;s eyes. For example, the reflective element may include a total internal reflection (TIR) optical element or a TIR waveguide for TIR. The TIR may be referred to as “one manner” for guiding light. The TIR may mean that light (e.g., an image) is incident such that all of the light input through the input grating area is reflected from one surface (e.g., a specific surface) of the waveguide, and then all of the light is delivered to the output grating area. According to an embodiment, the light emitted from the display may be guided to the waveguide through the input optical member (e.g., the first input optical member  221  and the second input optical member  223 ). The light traveling inside the waveguide may be induced toward the user&#39;s eye through an output optical member. According to an embodiment, the screen display area may be determined depending on the light emitted toward the user&#39;s eyes. According to an embodiment, the first waveguide  225  and the second waveguide  227  may be referred to differently as a “screen display area.” According to an embodiment, the first waveguide  225  may be at least a partial area of the first display  211 . The second waveguide  227  may be at least a partial area of the second display  213 . In the embodiment shown in  FIG. 2 , each of the first waveguide  225  and the second waveguide  227  are implemented in a quadrangle as an example, but not limited thereto. 
     According to an embodiment, the electronic device  201  may include a first camera module (e.g., the first camera  231  and the second camera  233 ). The electronic device  201  may perform head tracking, hand detection and tracking, gesture recognition, and spatial recognition of three degrees of freedom (3 DoF) or six degrees of freedom (6 DoF) by using the first camera module. For example, the first camera  231  and the second camera  233  may be global shutter (GS) cameras having the same specifications and performance (e.g., same or similar angles of view, shutter speeds, resolutions, and/or the number of color bits). The electronic device  201  may support simultaneous localization and mapping (SLAM) technology by performing spatial recognition and/or depth information acquisition by using stereo cameras arranged on the left and right sides. According to an embodiment, SLAM technology may refer to the technology in which a mobile robot measures its location while moving around an unknown environment, and creates a map of the surrounding environment at the same time. In addition, the electronic device  201  may recognize the user&#39;s gesture by using the stereo cameras arranged on the left/right sides. The electronic device  201  may detect faster hand gestures and finer movements by using a GS camera that has distortion less than a rolling shutter (RS) camera. 
     According to an embodiment, the electronic device  201  may include a second camera module (e.g., the third camera  235  and the fourth camera  237 ). According to an embodiment, the electronic device  201  may detect and track a pupil by using the second camera module. For example, the electronic device  201  may position the center of the virtual image displayed on the display so as to correspond to the gaze direction of the pupil of a user wearing the electronic device  201 , by using pupil information obtained by the second camera module. According to an embodiment, the second camera module may include a camera for tracking a right eye (e.g., the third camera  235 ) and a camera for tracking a left eye (e.g., the fourth camera  237 ). The third camera  235  and the fourth camera  237  may be GS cameras having the same specifications and performance (e.g., an angle of view, a shutter speed, a resolution, and/or the number of color bits). According to an embodiment, the electronic device  201  may track the pupil&#39;s fast movement by using a GS camera without screen afterimage. 
     According to an embodiment, the electronic device  201  may include a third camera module (e.g., the fifth camera  239 ). According to an embodiment, the third camera module may be referred to as a high-resolution camera or a photo/video camera. According to an embodiment, the third camera module may be a high-resolution camera. For example, the third camera module may be a color camera, which includes auto focus (AF) and/or optical image stabilizer (OIS) functions and which is equipped with a plurality of functions for obtaining high-quality images. According to an embodiment, the third camera module may be a global shutter camera or a rolling shutter camera. 
     According to an embodiment, light elements may include the first LED  241  and the second LED  243 . For example, the electronic device  201  may provide auxiliary lighting for the first camera module (e.g., the first camera  231  and the second camera  233 ), the second camera module (e.g., the third camera  235  and the fourth camera  237 ), and/or the third camera (e.g., the fifth camera  239 ) by using the first LED  241  and the second LED  243 . For example, when the electronic device  201  captures the user&#39;s pupil by using the second camera module (e.g., the third camera  235  and the fourth camera  237 ), the electronic device  201  may easily detect the user&#39;s gaze by using the first LED  241  and the second LED  243  as the auxiliary lighting. For example, the first LED  241  and the second LED  243  may include an infrared (IR) LED having an infrared wavelength. Even in a dark environment or an environment where a plurality of lighting elements emit light that are mixed and incident or reflected, the electronic device  201  may easily detect a subject with a camera module, by using the first LED  241  and the second LED  243  as the auxiliary lighting. 
     According to an embodiment, the PCB may include the first PCB  251  and the second PCB  253 . According to an embodiment, the PCB may be positioned in a temple. For example, the first PCB  251  may be positioned in the first temple member  205 . The second PCB  253  may be positioned in the second temple member  207 . According to an embodiment, the PCB may include a flexible PCB (FPCB). According to an embodiment, the first PCB  251  and the second PCB  253  may deliver an electrical signal to another component (e.g., a camera module (e.g., the first camera  231  to the fifth camera  239 ), a display (e.g., the first display  211  and the second display  213 ), an audio module (e.g., the first speaker  281  and the second speaker  283 ), and/or a sensor module (not shown)) and another PCB through the FPCB. According to an embodiment, a communication circuit (e.g., the communication module  190  of  FIG. 1 ) of the electronic device  201 , a processor (e.g., the processor  120  of  FIG. 1 ), a memory (e.g., the memory  130  of  FIG. 1 ), and/or at least one sensor (e.g., the sensor module  176  of  FIG. 1 ) may be disposed on the first PCB  251  and the second PCB  253 . For example, each of the first PCB  251  and the second PCB  253  may be composed of a plurality of PCBs spaced from one another by an interposer. 
     According to an embodiment, the microphone may include the first microphone  271 , the second microphone  273 , and/or the third microphone  275 . According to an embodiment, the microphone may be positioned on the frame  203  or on the bridge  209 . In the embodiment of  FIG. 2 , the first microphone  271  and the second microphone  273  may be positioned on the frame  203 , and the third microphone  275  may be positioned on the bridge  209 . According to an embodiment, the first microphone  271 , the second microphone  273 , and the third microphone  275  may receive a voice input from a user wearing the electronic device  201 . 
     According to an embodiment, the speaker may include the first speaker  281  and/or the second speaker  283 . According to an embodiment, the speaker may be positioned in the temple. In the embodiment of  FIG. 2 , the first speaker  281  may be positioned on the first temple member  205 , and the second speaker  283  may be positioned on the second temple member  207 . According to an embodiment, the first speaker  281  and the second speaker  283  may provide a sound signal to a user wearing the electronic device  201 . 
     According to an embodiment, the sensor module (not shown) may include at least one of a proximity sensor, an illuminance sensor, an acceleration sensor, a gyro sensor, a touch sensor, or a biometric sensor. The sensor module may detect a physical state (e.g., a posture or a location) of the electronic device  201 , an external environment state (e.g., the brightness of an object adjacent to the electronic device  201  or the brightness around the electronic device  201 ), or a state (e.g., electrocardiogram (ECG) or electro-encephalography (EEG) of a user) of a user wearing the electronic device  201  and then may generate an electrical signal or data value corresponding to the sensed state. 
     According to an embodiment, the biometric sensor may include an electrode and an analog front end (AFE). For example, the electrode may be provided in each of the first temple member  205  and the second temple member  207 . The biometric sensor may obtain the user&#39;s biometric signal from a portion where the first temple member  205  and the second temple member  207  come into contact with the user&#39;s skin through the electrode. For example, the biometric signal may include ECG or EEG. According to an embodiment, the AFE may be a circuit including an instrumentation amplifier (IA), a base pass filter (BPF), a variable gain amplifier (VGA), and an analog-to-digital (A/D) converter having a successive approximation register (SAR) type. The AFE may convert an analog signal obtained through the electrode into a digital signal and may transmit the digital signal to a processor (e.g., the processor  120  of  FIG. 1 ) of the electronic device  201 . For example, the processor of the electronic device  201  may evaluate the activity of the sympathetic nervous system and the parasympathetic nervous system through R-R interval of ECG or spectrum analysis of ECG. The processor of the electronic device  201  may determine that eye fatigue increases as the activity of the sympathetic nervous system increases. As another example, the processor of the electronic device  201  may extract a power value for each frequency band through spectrum analysis of EEG, and may evaluate eye fatigue by using the extracted power value. 
     According to an embodiment, the battery may include the first battery  291  and the second battery  293 . According to an embodiment, the battery may be positioned in the temple. In the embodiment of  FIG. 2 , the first battery  291  may be positioned on the first temple member  205 , and the second battery  293  may be positioned on the second temple member  207 . According to an embodiment, the first battery  291  and the second battery  293  may power the electronic device  201 . According to an embodiment, the first battery  291  and the second battery  293  may also be charged by an external power source. 
     Hereinafter, components of an electronic device according to an embodiment will be described with reference to  FIG. 3 . 
       FIG. 3  is a block diagram  300  of an electronic device  301 , according to an embodiment. According to an embodiment, the electronic device  301  may be the electronic device  101  of  FIG. 1  or the electronic device  201  of  FIG. 2 . 
     Referring to  FIG. 3 , the electronic device  301  according to an embodiment may include the processor  120  (e.g., the processor  120  of  FIG. 1 ), the communication module  190  (e.g., the communication module  190  of  FIG. 1 ), the power management module  188  (e.g., the power management module  188  of  FIG. 1 ), the sensor module  176  (e.g., the sensor module  176  of  FIG. 1 ), the camera module  180  (e.g., the camera module  180  of  FIG. 1 , or the first camera  231  to the fifth camera  239  of  FIG. 2 ), the memory  130  (e.g., the memory  130  of  FIG. 1 ), and/or the display module  160  (e.g., the display module  160  of  FIG. 1 , or the first display  211  and the second display  213  of  FIG. 2 ). According to an embodiment, the electronic device  201  may be connected to a second power management module  331  through a connection terminal  330  (e.g., USB TYPE-C). 
     According to an embodiment, the electronic device  301  may be a wearable device capable of being worn on a part of the user&#39;s body. For example, the electronic device  301  may be worn on the user&#39;s head. In this case, the display module  160  of the electronic device may include an HMD. Hereinafter, it may be assumed that the electronic device  301  to be described is a wearable electronic device that is worn on the user&#39;s head and in which the HMD is located in front of the user&#39;s eyes when being worn. The direction in which the user faces when the user wears the electronic device  301  may be referred to as a first direction. The direction opposite to the first direction, toward the user, may be referred to as a second direction. 
     According to an embodiment, the processor  120  may control at least one other component (e.g., hardware or software components) by executing a program (e.g., the program  140  of  FIG. 1 ) stored in the memory  130 , and may perform various data processing or operations. The processor  120  may include a microprocessor or any suitable type of processing circuitry, such as one or more general-purpose processors (e.g., ARM-based processors), a Digital Signal Processor (DSP), a Programmable Logic Device (PLD), an Application-Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), a Graphical Processing Unit (GPU), a video card controller, etc. In addition, it would be recognized that when a general purpose computer accesses code for implementing the processing shown herein, the execution of the code transforms the general purpose computer into a special purpose computer for executing the processing shown herein. Certain of the functions and steps provided in the Figures may be implemented in hardware, software or a combination of both and may be performed in whole or in part within the programmed instructions of a computer. No claim element herein is to be construed under the provisions of 35 U.S.C. 112(f), unless the element is expressly recited using the phrase “means for.” In addition, an artisan understands and appreciates that a “processor” or “microprocessor” may be hardware in the claimed disclosure. Under the broadest reasonable interpretation, the appended claims are statutory subject matter in compliance with 35 U.S.C. § 101. 
     According to an embodiment, the processor  120  may provide a user with VR service or AR service. For example, the processor  120  may output virtual space including at least one object through the display module  160 . According to an embodiment, content including the virtual space displayed through the display module  160  and at least one object may be referred to as VR content. As another example, the processor  120  may output at least one virtual object through the display module  160  to real space corresponding to the FOV of the user wearing the electronic device  301  such that the at least one virtual object is added to the real space and then the user watches the at least one virtual object. According to an embodiment, content including the real space displayed through the display module  160  and at least one virtual object may be referred to as AR content. For example, the display module  160  may display content, which is generated by the electronic device  301  or received from another electronic device (e.g., the electronic device  102  or  104  of  FIG. 1 , or the server  108  of  FIG. 1 ) through the communication module  190 . According to an embodiment, the processor  120  may store the VR content or the AR content in the memory  130 . 
     According to an embodiment, the display module  160  of the electronic device  301  may include at least one display panel (e.g., a first display panel (e.g., the first display  211 ) and/or a second display panel (e.g., the second display  213  of  FIG. 2 )). For example, the display panel may be composed of a transparent element such that the user is capable of perceiving the real space through the display module  160 . According to an embodiment, the display module  160  may display at least one virtual object on at least part of the display panel such that the user wearing the electronic device  301  views the virtual object added to the real space. For example, the user&#39;s FOV may include an angle or range at which the user is capable of recognizing an object. 
     According to an embodiment, the sensor module  176  of the electronic device  301  may include a proximity sensor  321 , an illuminance sensor  322 , a gyro sensor  323 , and/or a biometric sensor  324 . According to an embodiment, the proximity sensor  321  may detect an object adjacent to the electronic device  301 . The illuminance sensor  322  may measure the degree of brightness around the electronic device  301 . According to an embodiment, the gyro sensor  323  may detect the posture and location of the electronic device  301 . For example, the gyro sensor  323  may detect whether the electronic device  301  is properly worn on the user&#39;s head. As another example, the gyro sensor  323  may detect a movement of the electronic device  301  or a user wearing the electronic device  301 . According to an embodiment, the biometric sensor  324  may measure the ECG and EEG of the user wearing the electronic device  301 . 
     According to an embodiment, the electronic device  301  may perform wireless communication with another electronic device (e.g., the electronic device  102  or  104  of  FIG. 1 ) through the communication module  190  (e.g., a wireless communication circuit). For example, the electronic device  301  may perform wireless communication with a portable electronic device (e.g., a smartphone). The electronic device  301  may be at least partially controlled by another external electronic device (e.g., a portable electronic device). For example, the electronic device  301  may perform at least one function under the control of another external electronic device. 
     According to an embodiment, the camera module  180  of the electronic device  301  may include a gesture camera  311  (e.g., the first camera  231  and the second camera  233  of  FIG. 2 ), an eye tracking camera  313  (e.g., the third camera  235  and the fourth camera  237  of 
       FIG. 2 ), a depth camera  315  (e.g., the first camera  231  and the second camera  233  of  FIG. 2 ), and/or a red-green-blue (RGB) camera  317  (e.g., the fifth camera  239  of  FIG. 2 ). 
     The gesture camera  311  may detect the user&#39;s movement. For example, at least one or more of the gesture cameras  311  may be positioned on the electronic device  301  and may detect the movement of the user&#39;s hand within a preset distance. The gesture camera  311  may include a simultaneous localization and mapping camera (SLAM camera) for recognizing information (e.g., a location and/or direction) associated with the surrounding space of the electronic device  301 . The gesture recognition area of the gesture camera  311  may be set based on the available shooting range of the gesture camera  311 . 
     According to an embodiment, the eye tracking camera  313  may detect and track the size, location, and movement of the user&#39;s pupil. According to an embodiment, the eye tracking camera  313  may include a plurality of cameras (e.g., the third camera  235  and the fourth camera  237  of  FIG. 2 ) corresponding to the user&#39;s left and right eyes, respectively. According to an embodiment, the processor  120  may determine the user&#39;s eye condition (e.g., fatigue) or gaze direction by using the eye tracking camera  313 . According to an embodiment, the processor  120  may determine the degree of eye fatigue based on at least one of eye flicker frequency, pupil adjustment speed, the degree of eye dryness, the degree of eye redness, or the degree of pupil tremor. 
     According to an embodiment, the depth camera  315  may measure the distance to an object positioned in front of the electronic device  301 . The depth camera  315  may include a time of flight (TOF) camera and/or a depth camera. According to an embodiment, the electronic device  301  may recognize one of the objects located in the gaze direction of the user by using the eye tracking camera  313  and may calculate depth, that is, a distance to the object, through the depth camera or may measure a distance to the object through the TOF camera. According to an embodiment, the RGB camera  317  may detect color-related information of an object and information about a distance from the object. 
     According to an embodiment, the gesture camera  311 , the eye tracking camera  313 , the depth camera  315 , and/or the RGB camera  317  included in the camera module  180  may be included in the electronic device  301 ; alternatively, some of the gesture camera  311 , the eye tracking camera  313 , the depth camera  315 , and/or the RGB camera  317  may be implemented as an integrated camera. For example, the depth camera  315  and the RGB camera  317  may be implemented as one integrated camera. 
     According to an embodiment, the gesture camera  311 , the depth camera  315 , and the RGB camera  317  may be arranged to capture an image in the gaze direction of the user&#39;s eyes. The eye tracking camera  313  may be arranged to capture the user&#39;s eyes. 
     The number and location of at least one camera (e.g., the gesture camera  311 , the eye tracking camera  313 , the depth camera  315 , and/or the RGB camera  317 ) included in the electronic device  301  illustrated in  FIG. 3  may not be limited thereto. For example, the number and location of at least one camera may vary based on a characteristic (e.g., shape or size) of the electronic device  301 . 
     According to an embodiment, the power management module ( 188 ,  331 ) may manage power supplied to the electronic device  301 . The power management module ( 188 ,  331 ) may include the first power management module  188 , which is directly connected to the processor  120  so as to supply power to the processor  120 , and the second power management module  331  that supplies power through the connection terminal  330  (e.g., TYPE-C). The second power management module  331  may be functionally connected to a battery  333  so as to manage more power. According to an embodiment, the electronic device  301  may drive at least one camera included in the camera module  180  by using the power supplied from the power management module ( 188 ,  331 ). The electronic device  201  may manage power consumption by adjusting display information provided through the display module  160  based on information obtained by using the at least one camera. 
     Hereinafter, components and operations of an electronic device according to an embodiment will be described with reference to  FIG. 4 . 
       FIG. 4  is a block diagram  400  of an electronic device  401 , according to an embodiment. According to an embodiment, the electronic device  401  may be the electronic device  101  of  FIG. 1 , the electronic device  201  of  FIG. 2 , or the electronic device  301  of  FIG. 3 . It is assumed that the electronic device  401  described below is a device capable of being worn on the user&#39;s head and may be the pair of glasses, for example, as shown in  FIG. 2 . 
     Referring to  FIG. 4 , the electronic device  401  according to an embodiment may include an eye tracking module  410 , a display  420  (e.g., the display module  160  of  FIGS. 1 and 3 , or the first display  211  and the second display  213  of  FIG. 2 ), a processor  430  (e.g., the processor  120  in  FIGS. 1 and 3 ), and a memory  440  (e.g., the memory  130  of  FIGS. 1 and 3 ). 
     According to an embodiment, the eye tracking module  410  may include a camera module  411  (e.g., the camera module  180  of  FIGS. 1 and 3 , or the first camera  231  to the fifth camera  239  of  FIG. 2 ). The detailed description of the camera module  411  is duplicative of the description given with reference to  FIGS. 1 to 3 , and thus the detailed disclosure will be simplified or omitted to avoid redundancy. According to an embodiment, the camera module  411  may capture the eye or pupil of the user wearing the electronic device  401 . According to an embodiment, the processor  430  to be described may obtain eye tracking data indicating states of the user&#39;s eyes based on an image captured by the camera module  411 . According to an embodiment, the processor  430  may obtain the eye tracking data for a specified period. 
     According to an embodiment, the display  420  may display content. The content may include, for example, VR content or AR content. According to an embodiment, the content may include at least one object. According to an embodiment, the object may include a virtual object. For example, the object may include text or image. Herein, the image may include static images and dynamic images. According to an embodiment, the object may include information in various forms capable of being perceived visually by the user. A detailed description of the display  420  is duplicative of the description given above with reference to  FIGS. 1 to 3 , and thus the detailed disclosure will be simplified or omitted to avoid redundancy. 
     According to an embodiment, the user may watch content output through the display  420 , and the user may feel eye fatigue due to viewing the content. 
     According to an embodiment, the processor  430  may be operatively or functionally connected to the camera module  411  and the display  420 . According to an embodiment, the processor  430  may determine an eye fatigue level based on the user&#39;s eye tracking data obtained by using the camera module  411 . According to an embodiment, the processor  430  may control a setting of the display  420  or an output setting of content, which is to be output on the display  420 , depending on the determined eye fatigue level. 
     According to an embodiment, the processor  430  may determine the eye fatigue level based on the eye tracking data. For example, the eye tracking data may include measurement values for a plurality of parameters. According to an embodiment, the plurality of parameters may be associated with eye fatigue and may include information indicating the state or movement of eyes or pupils. For example, the plurality of parameters may include at least one of eye flicker frequency, pupil adjustment speed, the degree of eye dryness, the degree of eye redness, or the degree of pupil tremor. 
     According to an embodiment, the processor  430  may classify the eye fatigue into a plurality of levels (e.g., level 1 to level n (‘n’ is a natural number of 2 or more)). According to an embodiment, the eye fatigue level may increase as the eye fatigue increases. According to an embodiment, the processor  430  may determine the eye fatigue level depending on a condition consisting of at least one parameter among the plurality of parameters or a combination of the at least two parameters among the plurality of parameters. According to an embodiment, the condition may include at least one parameter or a combination of at least two parameters, and may include a threshold range or threshold value for each parameter. A method in which the processor  430  determines an eye fatigue level will be described later in detail with reference to  FIG. 5 . 
     According to an embodiment, the processor  430  may determine the eye fatigue level by applying a weight for each parameter. According to an embodiment, the processor  430  may identify a weight for each parameter of the plurality of parameters. According to an embodiment, the weight for each parameter may be different for each user. The processor  430  may identify the weight for each parameter based on user identification information. According to an embodiment, the processor  430  may apply a weight for each parameter to at least one parameter. 
     According to an embodiment, the electronic device  401  may further include a sensor module  413  (e.g., the sensor module  176  of  FIGS. 1 and 3 ). According to an embodiment, the sensor module  413  may include a biometric sensor capable of measuring a biometric signal of the user wearing the electronic device  401 . The detailed description of the sensor module  413  or the biometric sensor is duplicative of the description given with reference to  FIGS. 1 to 3 , and thus the detailed disclosure will be simplified or omitted to avoid redundancy. According to an embodiment, the processor  430  may obtain a biometric signal by using the sensor module  413 . For example, the biometric signal may include at least one of ECG and EEG. According to an embodiment, the processor  430  may determine the user&#39;s eye fatigue level further based on the biometric signal measured by the sensor module  413 . For example, the processor  430  may analyze the ECG or EEG and may use the analysis result to determine the user&#39;s eye fatigue level. According to an embodiment, the ECG or EEG may be used as another parameter for determining the eye fatigue level. 
     According to an embodiment, the processor  430  may determine the eye fatigue level further based on usage history information of the electronic device  401 . According to an embodiment, the usage history information of the electronic device  401  may include at least one of the usage time of the electronic device  401 , the setting (e.g., illumination level) of the display  420 , or the type of application being executed. For example, as the usage time of the electronic device  401  increases, the user&#39;s eye fatigue may increase. For example, as the illuminance of the display  420  increases, the user&#39;s eye fatigue may increase. For example, if the displayed screen changes frequently or if the executing application (e.g., game application) has a lot of objects moving on the screen, the user&#39;s eye fatigue may increase. According to an embodiment, when the processor  430  is not capable of obtaining the user&#39;s eye tracking data or biometric signal, the processor  430  may determine the eye fatigue level based on the usage history information of the electronic device  401 . The processor  430  may determine the eye fatigue level more accurately by additionally taking into account the usage history information of the electronic device  401  to the user&#39;s eye tracking data or biometric signal. 
     According to an embodiment, the processor  430  may control a setting of the display  420  or an output setting of content, which is to be output on the display  420 , depending on the determined eye fatigue level. According to an embodiment, an item related to a setting of the display  420  may include at least one of a scan rate (unit: Hz) or brightness, but is not limited thereto. For example, the processor  430  may change the setting of the display  420  by changing at least one of the scan rate and brightness. According to an embodiment, an item related to an output setting of content to be output on the display  420  may include at least one of the number, sizes, locations, colors, or stereoscopic effect levels of objects output on the display  420 . For example, the processor  430  may change the output setting of content to be output on the display  420  by changing at least one of the number, sizes, locations, colors, or stereoscopic effect levels of the objects output on the display  420 . 
     According to an embodiment, the processor  430  may adjust the eye fatigue level based on content, which is to be output, from among content output to the display  420 . According to an embodiment, the content to be output may include at least part of content that is not yet output although the output is scheduled from among the content output on the display  420 . For example, the content to be output may include content including determined information to be displayed later on the display  420  such as execution of a game displaying a specified screen or playback a video. The processor  430  may predict a change in an eye fatigue level based on the content to be output. The processor  430  may reduce the increase in the actual eye fatigue level by attempting to adjust the eye fatigue level and predicting the change in the eye fatigue level. According to an embodiment, when it is predicted that the eye fatigue level currently determined by the processor  430  is 3, and the eye fatigue level after all pieces of content to be output is completely output is  7 . Accordingly, the processor  430  may change the eye fatigue level, which is determined as 3, into 5, and thus may change the setting of the display  420  so as to correspond to level 5. For example, the eye fatigue level determined by the processor  430  after all pieces of content to be output are output may be level 6, not level 7 thus predicted. 
     According to an embodiment, the memory  440  may store various data used by at least one component (e.g., the processor  430 , the camera module  411 , or the sensor module  413 ) of the electronic device  401 . For example, data may include software (e.g., a program) and input data or output data for instructions associated with the software. According to an embodiment, the memory  440  may store one or more instructions executable by the processor  430 . 
     Hereinafter, a method for determining an eye fatigue level by an electronic device according to an embodiment will be described with reference to  FIG. 5 . 
       FIG. 5  is a flowchart  500  illustrating an operating method of an electronic device, according to an embodiment. Operations of an electronic device to be described below may be performed by an electronic device (e.g., the electronic device  401  of  FIG. 4 ) or a processor (e.g., the processor  430  of  FIG. 4 ) of the electronic device according to an embodiment. 
     In operation  501 , the electronic device may identify an initial value of eye tracking data. According to an embodiment, the eye tracking data may be obtained by using a camera module (e.g., the camera module  411  of  FIG. 4 ) of the electronic device. The eye tracking data may include measurement values for a plurality of parameters related to a user&#39;s eye fatigue. For example, the plurality of parameters may include at least one of eye flicker frequency, pupil adjustment speed, the degree of eye dryness, the degree of eye redness, or the degree of pupil tremor. 
     According to an embodiment, an initial value of the eye tracking data may include a measurement value obtained as the electronic device first measures a plurality of parameters after the user wears the electronic device. For example, the initial value of the eye tracking data may include an average value during a specified time period from a point in time when the user wears the electronic device. According to another embodiment, the initial value of the eye tracking data may include a value preset as a value input by the user through an input module (e.g., the input module  150  of  FIG. 1 ) (e.g., a touch screen display) of the electronic device. 
     According to an embodiment, the initial value of the eye tracking data may include an average value determined based on the user&#39;s history information. For example, the user&#39;s history information may include information obtained by storing an average value during a specified time period during which the electronic device is worn for each user after the electronic device identifies the user. According to an embodiment, when identifying that a user wears the electronic device, the electronic device may identify the user. The electronic device may set the average value of the identified user as the initial value based on the user&#39;s history information. For example, the electronic device may identify the user through biometric authentication. 
     According to an embodiment, the electronic device may further include a communication module (e.g., the communication module  190  of  FIGS. 1 and 3 ). The electronic device may receive setting information and usage history information of an external electronic device (e.g., the electronic device  102  of  FIG. 1 , or the electronic device  104  of  FIG. 1 ) from the user&#39;s external electronic device (e.g., the electronic device  102  of  FIG. 1 , the electronic device  104  of  FIG. 1 , or the server  108 ) through the communication module. According to an embodiment, the electronic device and the external electronic device may include an electronic device in which the same user information is registered. According to an embodiment, the electronic device may set the initial value of eye tracking data based on setting information and usage history information of the external electronic device. 
     According to an embodiment, the setting information of the external electronic device may include an initial value of eye tracking data set for the external electronic device. For example, when the initial value of the user&#39;s eye tracking data is already set for another electronic device with respect to the same user, the electronic device may determine the initial value of the eye tracking data in the electronic device by using the initial value information set for the other electronic device. 
     According to an embodiment, the usage history information of the external electronic device may include at least one of usage time of the external electronic device, a setting of a display of the external electronic device, or a list of applications recently executed in the external electronic device. For example, when the user has a history of using the external electronic device before the user employs the wearable electronic device, the electronic device may set the initial value of the eye tracking data in the electronic device based on the usage history information of the external electronic device. 
     In operation  503 , the electronic device may calculate the amount of change compared to the initial value of the obtained eye tracking data. According to an embodiment, the electronic device may obtain eye tracking data at a specified time period. The electronic device may obtain measurement values for a plurality of parameters at a specified period. The measurement values for the plurality of parameters may increase or decrease as the user&#39;s eye fatigue increases. According to an embodiment, the electronic device may calculate the amount of change compared to the initial value of the measurement values for a plurality of parameters obtained at a specified period and then may calculate the amount of change compared to the initial value of the eye tracking data. 
     In operation  505 , the electronic device may determine the eye fatigue level depending on the amount of change. For example, the eye fatigue level may include a plurality of levels (e.g., level 1 to level n (‘n’ is a natural number of 2 or more)). According to an embodiment, the electronic device may determine the eye fatigue level depending on whether the amount of change is greater than or equal to a specified threshold value or whether the amount of change satisfies the specified threshold range for the eye fatigue level. For example, the electronic device may determine the eye fatigue level as the amount of change in eye tracking data increases. The amount of change in eye tracking data may be referred to as the amount of change compared to the initial value of a measurement value for a specific parameter (e.g., eye flicker frequency or pupil adjustment speed) to be described below. For example, the amount of change in eye tracking data may be a decrease or an increase in the measurement value for a parameter. According to an embodiment, as the eye fatigue level is higher, the threshold value or threshold range corresponding to the corresponding level may include a greater value. 
     According to an embodiment, the electronic device may determine the eye fatigue level depending on a condition consisting of at least one parameter among a plurality of parameters or a combination of at least two parameters. According to an embodiment, the condition may include at least one parameter or a combination of at least two parameters, and may include a threshold value or threshold range for each parameter. For example, a condition that the eye fatigue level is determined to be level k (V is a natural number between 1 and n) may include a first parameter (e.g., eye flicker frequency) and a second parameter (e.g., pupil adjustment speed), and may include a threshold value (or a threshold range) of the first parameter and a threshold value (or a threshold range) of the second parameter, which correspond to level k. According to an embodiment, as the amount of change compared to the initial value of the measurement value for each parameter is greater than or equal to a threshold value corresponding to each level or satisfies the threshold range corresponding to each level, the electronic device may determine the user&#39;s eye fatigue level as the corresponding level. For example, when the amount of change compared to the initial value of the measurement value for the first parameter is greater than the threshold value of the first parameter corresponding to level k, the amount of change satisfies the threshold range of the first parameter corresponding to level k. When the amount of change from the initial value of the measurement value for the second parameter is greater than the threshold value of the second parameter corresponding to level k, the amount of change satisfies a threshold range of the second parameter corresponding to level k. Accordingly, the electronic device may determine the eye fatigue level as level k. In the above-described embodiment, it is described that a condition for determining the eye fatigue level consists of a combination of two parameters. However, an embodiment is not limited thereto. 
     According to an embodiment, the electronic device may determine the eye fatigue level by applying a weight for each parameter. For example, the electronic device may apply a weight for each parameter by reducing a threshold value corresponding to the eye fatigue level of at least one parameter, but is not limited thereto. According to an embodiment, as the weight for any parameter increases, the electronic device may determine greater eye fatigue for the same amount of change. According to an embodiment, as the weight is high even though the amount of change is small, it may significantly affect the determination of the eye fatigue level. On the other hand, as the weight is low even though the amount of change is greater, it may not significantly affect the determination of an eye fatigue level. According to an embodiment, the eye flicker frequency and pupil adjustment speed among the plurality of parameters may have relatively high weights compared to other parameters. 
     In operation  505 , the electronic device may determine the eye fatigue level further based on a biometric signal obtained by using a biometric sensor (e.g., the sensor module  413  of  FIG. 4 ). According to an embodiment, the biometric signal may include ECG or EEG. According to an embodiment, the electronic device may use ECG or EEG as one of parameters for determining an eye fatigue level. According to an embodiment, the electronic device may apply a weight for each parameter to ECG or EEG. For example, the weights of ECG or EEG may be lower than the weight of a parameter included in the eye tracking data. 
     In operation  505 , the electronic device may determine the eye fatigue level further based on usage history information of the electronic device. According to an embodiment, the usage history information of the electronic device may include at least one of the usage time of the electronic device, the setting (e.g., illumination) of a display (e.g., the display  420  of  FIG. 4 ), or the type of an application being executed. For example, even though the amount of change in the user&#39;s eye tracking data or the change in the user&#39;s biometric signal is not great, when the usage time of the electronic device is long, the illumination of the display is high, or a lot of screen changes or a lot of movements within a screen are present, the electronic device may determine the user&#39;s eye fatigue level so as to be high. According to an embodiment, the electronic device may use the usage history information of the electronic device as one of parameters for determining an eye fatigue level. According to an embodiment, the electronic device may apply a relatively low weight to the usage history information of the electronic device compared to the user&#39;s eye tracking data or biometric signal. 
     In operation  507 , the electronic device may control at least one of a setting of a display and an output setting of content depending on the determined eye fatigue level. According to an embodiment, an item related to the setting of the display may include at least one of scan rate and brightness. An item related to the output setting of content may include at least one of the number, sizes, locations, colors, or stereoscopic effect levels of objects output to the display. For example, the electronic device may change at least one of the scan rate or brightness of the display depending on the eye fatigue level. As another example, the electronic device may change at least one of the number, sizes, locations, colors, or stereoscopic effect levels of objects output to the display depending on the eye fatigue level. 
     For example, as the display is brighter or the scan rate of the display is higher, the user&#39;s eye fatigue level may be higher. As the eye fatigue level is determined to be higher than a specific level, the electronic device may lower the brightness of the display or may lower the scan rate of the display. 
     In another example, as the number of objects output on the display increases or sizes of objects decreases, the user&#39;s eye fatigue level may be increased. As the eye fatigue level is determined to be higher than the specific level, the electronic device may reduce the number of objects displayed on the display or may increase sizes of the objects. As another example, when an object is positioned to disrupt user experience or the object has a layout that disturbs the user experience, such as when a main object is located at the edge of a screen and a sub-object is located at the center of the screen, the user&#39;s eye fatigue level may increase. As the eye fatigue level is determined to be higher than a specific level, the electronic device may change the locations or arrangement of objects displayed on a display in consideration of user experience. As another example, when the color of the object is not black and white, the user&#39;s eye fatigue level may be higher than that in a case of black and white. As the eye fatigue level is determined to be higher than the specific level, the electronic device may change the color of an object displayed to black and white or greyscale. As another example, as a stereoscopic effect level of an object is high, the user&#39;s eye fatigue level may increase. As the eye fatigue level is determined to be higher than the specific level, the electronic device may lower the stereoscopic effect level of an object displayed on a display. 
     According to an embodiment, the electronic device may change only the setting of the display, or may change both the setting of the display and an output setting of content. According to an embodiment, the electronic device may have a plurality of modes depending on whether it is changing the setting of the display or the output setting of content. For example, the mode in which the electronic device changes only the setting of the display may be referred to as a “first mode.” The mode in which the electronic device changes both the setting of the display and an output setting of content may be referred to as a “second mode”. 
     According to an embodiment, the electronic device may have various modes depending on an item for changing a setting or the number of items for changing the setting. 
     Hereinafter, a method in which the electronic device according to an embodiment selects one of a plurality of modes depending on an eye fatigue level will be described with reference to  FIG. 6 . 
       FIG. 6  is a flowchart  600  illustrating a method of operating an electronic device, according to an embodiment. Operations of an electronic device to be described below may be performed by an electronic device (e.g., the electronic device  401  of  FIG. 4 ) or a processor (e.g., the processor  430  of  FIG. 4 ) of the electronic device according to an embodiment. 
     In operation  601 , the electronic device may identify an eye fatigue level. According to an embodiment, the electronic device may determine the eye fatigue level depending on the process shown in  FIG. 5 . Alternatively, the electronic device may receive an eye fatigue level from a user via user input. The electronic device may identify the determined eye fatigue level or the input eye fatigue level. 
     In operation  603 , the electronic device may determine whether the identified eye fatigue level is greater than or equal to a first threshold value. For example, assuming that the eye fatigue level is from level 1 to level 10, the first threshold value may be one of 1 to 10. According to an embodiment, when it is determined that the eye fatigue level is greater than or equal to the first threshold value (“Yes”), the electronic device may perform operation  605 . When it is determined that the eye fatigue level is less than the first threshold value (“No”), the electronic device may perform operation  601 . According to an embodiment, the electronic device may perform operation  601  at a specified period. For example, when it is determined that the eye fatigue level is less than the first threshold value (“No”) in operation  603 , the electronic device may perform operation  601  after a specified time has elapsed. 
     In operation  605 , the electronic device may determine whether the eye fatigue level is greater than or equal to a second threshold value. For example, assuming that the eye fatigue level is from level 1 to level 10, the second threshold value may be one of 1 to 10. According to an embodiment, the second threshold value may be a value greater than the first threshold value. According to an embodiment, when it is determined that the eye fatigue level is greater than or equal to the second threshold value (“Yes”), the electronic device may perform operation  609 . When it is determined that the eye fatigue level is less than the second threshold value (“No”), the electronic device may perform operation  607 . According to an embodiment, when it is determined that the eye fatigue level is less than the second threshold value (“No”) in operation  605 , the eye fatigue level may be greater than the first threshold value and may be less than the second threshold value. 
     According to an embodiment, when the eye fatigue level is greater than or equal to the first threshold value and is less than the second threshold value, the electronic device may select a first mode (operation  607 ). When the eye fatigue level is greater than or equal to the second threshold value, the electronic device may select a second mode (operation  609 ). 
     In operation  607 , the electronic device may select the first mode. According to an embodiment, the first mode may be a mode in which only the setting of the display is changed from among the setting of the display and the output setting of content. For example, as the electronic device selects the first mode, the electronic device may lower the brightness of the display or may lower the scan rate of the display. 
     In operation  609 , the electronic device may select the second mode. According to an embodiment, the second mode may be a mode in which both the setting of the display and the output setting of content are changed. For example, as the electronic device selects the second mode, the electronic device may lower the brightness or scan rate of the display, and may reduce the number of objects or may increase sizes of objects, but is not limited thereto. 
     According to the above-described embodiment, as it is determined that the eye fatigue level is greater than or equal to the first threshold value, the electronic device may change an item related to the setting of a display. As it is determined that the eye fatigue level is greater than or equal to the second threshold value, the electronic device may change the item related to the output setting of the content in addition to changing the item related to the setting of a display. The electronic device may control the setting of a display or the output setting of content step by step depending on an eye fatigue level. The electronic device may reduce a speed, at which the user&#39;s eye fatigue is accumulated, by changing the setting of a display or the output setting of content depending on the eye fatigue level. 
     Hereinafter, a method of changing, by an electronic device according to an embodiment, a setting of a display or an output setting of content will be described with reference to  FIG. 7 . 
       FIG. 7  is a flowchart  700  illustrating a method of operating an electronic device, according to an embodiment. Operations of an electronic device to be described below may be performed by an electronic device (e.g., the electronic device  401  of  FIG. 4 ) or a processor (e.g., the processor  430  of  FIG. 4 ) of the electronic device according to an embodiment. 
     In operation  701 , the electronic device may identify an eye fatigue level. Operation  701  is the same as operation  601  of  FIG. 6 , and thus a detailed description thereof is omitted. 
     In operation  703 , the electronic device may determine whether the identified eye fatigue level is greater than or equal to a threshold value. Operation  703  may correspond to operation  603  to operation  605  in  FIG. 6 . According to an embodiment, when the eye fatigue level is less than a first threshold value, the electronic device may perform operation  701  again. When the eye fatigue level is greater than or equal to the first threshold value, the electronic device may perform operation  705 . According to an embodiment, when the eye fatigue level is greater than or equal to the first threshold value and is less than a second threshold value, the electronic device may select a first mode in which only the setting of a display (e.g., the display  420  in  FIG. 4 ) is changed. When the eye fatigue level is greater than or equal to the second threshold value, the electronic device may select a second mode in which both the setting of the display and the output setting of content are changed. 
     In operation  705 , the electronic device may determine whether to automatically set a specified setting value for each selected mode. According to an embodiment, the electronic device may provide a user with a user interface that allows the user to select automatic settings. The user may select the automatic settings through the provided user interface. Depending on receiving the user&#39;s selection input that selects automatic settings (“Yes”), the electronic device may perform operation  707  to operation  711 . Depending on receiving the user&#39;s selection input that does not select automatic settings (selecting a manual settings) (“No”), the electronic device may perform operation  713  to operation  717 . In the above-described embodiment, it is described that an electronic device receives a user input and then determines automatic settings, but is not limited thereto. The automatic settings may be determined by identifying a predetermined setting value for the automatic settings. 
     In operation  707 , the electronic device may identify the setting state of a display and the output setting state of content. According to an embodiment, the electronic device may identify the setting state of a display and the output setting state of content at a point in time when operation  701  is performed. For example, the electronic device may identify the brightness of the display and the scan rate of the display at a point in time when operation  701  is performed. For example, the electronic device may identify the number, sizes, locations, colors, or stereoscopic effect levels of objects output to the display at a point in time when operation  701  is performed. 
     In operation  709 , the electronic device may change at least one of the setting of a display and the output setting of content depending on the eye fatigue level. As the electronic device performs operation  703  based on the eye fatigue level identified in operation  701 , the electronic device may select one (e.g., the first mode or the second mode) of a plurality of modes. The electronic device may change at least one of a setting of a display or an output setting of content depending on the selected mode. According to an embodiment, the electronic device may change the setting of the display when selecting the first mode. For example, in the first mode, the electronic device may change at least one of brightness of the display or a scan rate of the display to an automatic setting value. According to an embodiment, the electronic device may change the output setting of the content displayed on the display when selecting the second mode. For example, in the second mode, the electronic device may change at least one of the number, sizes, locations, colors, or stereoscopic effect levels of objects output to the display to an automatic setting value. 
     According to an embodiment, the automatic setting value may include setting values of items related to the setting of the display or the output setting of the content, which are determined depending on the eye fatigue level. The automatic setting value may be stored in a memory (e.g., the memory  440  of  FIG. 4 ) of the electronic device. According to an embodiment, the electronic device may determine the automatic setting value based on history information including the change of the user&#39;s eye fatigue level according to a change in a setting item. 
     In operation  711 , the electronic device may render content based on the setting of the display and the output setting of the content and then may output an image generated by the rendering. According to an embodiment, the electronic device may render the content displayed on the display based on the setting of the display and the output setting of the content that are changed to the automatic setting value in operation  709 . The electronic device may generate a final image output to the display by rendering the content. The electronic device may output the generated final image to the display. 
     According to an embodiment, when the automatic setting is not selected, the electronic device may perform operation  713  to operation  717 . 
     In operation  713 , the electronic device may display a user interface (UI) indicating the setting state of the display and the output setting state of the content. For example, the electronic device may display the UI including information about the setting state of the display and the output setting state of the content on the display at a point in time when operation  701  is performed. For example, the user interface may include a current setting value and at least one component capable of changing a setting value for each item with respect to items related to the setting of the display or the output setting of the content. The electronic device may allow the user to directly change the setting of the display or the output setting of the content through the user interface. According to an embodiment, as the electronic device selects the first mode, the electronic device may provide the UI including only an item related to the setting of the display. As the electronic device selects the second mode, the electronic device may provide the UI including both an item related to the setting of the display and an item related to the output setting of the content. 
     In operation  715 , the electronic device may receive the user&#39;s setting input and then may change at least one of the setting of the display and the output setting of the content. For example, the electronic device may receive the user&#39;s setting input for changing at least one setting value of items related to the setting of the display and the output setting of the content through the UI. The electronic device may change at least one of the setting of the display and the output setting of the content based on the received setting input of a user. For example, the electronic device may change at least one of the setting of the display and the output setting of the content by changing a current setting value for each item output through the UI to a setting value entered by the user. 
     In operation  717 , the electronic device may render content based on the setting of the display and the output setting of the content and then may output an image generated by rendering. According to an embodiment, the electronic device may render the content displayed on the display based on the setting of the display and the output setting of the content that are changed to the setting value entered by the user in operation  715 . The electronic device may generate the final image output to the display by rendering the content and then may output the generated final image to the display. 
     Hereinafter, a relationship between a scan rate of a display and eye fatigue and a method in which an electronic device according to an embodiment changes the scan rate of the display depending on an eye fatigue level will be described with reference to  FIG. 8 . 
       FIG. 8  is a diagram  800  illustrating an example of changing a display setting of an electronic device, according to an embodiment. Operations of an electronic device to be described below may be performed by an electronic device (e.g., the electronic device  401  of  FIG. 4 ) or a processor (e.g., the processor  430  of  FIG. 4 ) of the electronic device according to an embodiment. 
     According to an embodiment, the scan rate of a display (e.g., the display  420  of  FIG. 4 ) may refer to the number of times that the display outputs screens per second or the number of screens output by the display per second. The unit of the scan rate of the display may be is Hertz (Hz). According to an embodiment, the scan rate may also be referred to as “screen refresh rate.” According to an embodiment, as the screen is refreshed, the display may flicker. 
     Referring to  FIG. 8 , motion blur effect may appear more strongly as the scan rate of the display is lower. For example, as the scan rate decreases to 120 Hz, 90 Hz, and 60 Hz, the motion blur effect may become more prominent. According to an embodiment, the motion blur may refer to a graphic effect in which afterimages occur when objects on the screen move. For example, the motion blur effect may occur when the user moves while wearing an electronic device or when changing his/her gaze. According to an embodiment, when the motion blur effect occurs prominently by a specific level or higher, the user may perceive the flicker of the screen, and thus the user may feel eye fatigue. For example, when the scan rate of the display is greater than 90 Hz, the user may not perceive the flicker. 
     According to an embodiment, the electronic device may increase the scan rate of the display, thereby reducing the motion blur effect and the user&#39;s eye fatigue. According to an embodiment, as it is determined that the user&#39;s eye fatigue level is greater than a specific level, the electronic device may reduce the speed at which the user&#39;s eye fatigue is accumulated by increasing the scan rate of the display. For example, the electronic device may set the scan rate of the display to 90 Hz or higher such that the user may feel less eye fatigue. 
     According to an embodiment, as the scan rate of the display is high, the battery consumption may increase. For example, the electronic device may determine the scan rate of the display in consideration of the battery consumption and the user&#39;s eye fatigue level. 
     Hereinafter, a relationship between the number or sizes of objects and eye fatigue, and a method in which the electronic device according to an embodiment changes the number or sizes of objects output to the display depending on an eye fatigue level will be described with reference to  FIG. 9 . 
       FIG. 9  is a diagram  900  illustrating an example of changing an output setting of content of an electronic device, according to an embodiment. Operations of an electronic device to be described below may be performed by an electronic device (e.g., the electronic device  401  of  FIG. 4 ) or a processor (e.g., the processor  430  of  FIG. 4 ) of the electronic device according to an embodiment. 
     A first screen  901  and a second screen  902  of  FIG. 9  show screens displayed on a display (e.g., the display  420  of  FIG. 4 ) of the electronic device, and indicate the same content (e.g., navigation content). 
     Referring to the first screen  901 , the electronic device may display a first object  911   a , a second object  912   a , a third object  913   a , a fourth object  914   a , and a fifth object  915   a  in a first area  910   a  of the display. For example, the first object  911   a  may be an object including current time information; the second object  912   a  may be an object including instantaneous fuel efficiency information; the third object  913   a  may be an object including average speed information; the fourth object  914   a  may be an object including remaining distance information; and, the fifth object  915   a  may be an object including arrival time information. The electronic device may display a sixth object  921   a , a seventh object  922   a , and an eighth object  923   a  in a second area  920   a  of the display. For example, the sixth object  921   a , the seventh object  922   a , and the eighth object  923   a  may be objects including the following path information. The sixth object  921   a  may include path information immediately following a current path; the seventh object  922   a  may include path information following the path included in the sixth object  921   a ; and, the eighth object  923   a  may include path information following the path included in the seventh object  922   a.    
     According to an embodiment, the electronic device may change the number or sizes of objects displayed on the display depending on the eye fatigue level. Hereinafter, it is assumed that the eye fatigue level identified by the electronic device in the second screen  902  is higher than the eye fatigue level in the first screen  901 . According to an embodiment, as the eye fatigue level increases, the electronic device may reduce the number of objects displayed on the display and may increase sizes of the objects displayed on the display. 
     Referring to the second screen  902 , the electronic device may display a first object  911   b  and a fifth object  915   b  in a first area  910   b . According to an embodiment, the electronic device may reduce the number of objects displayed in the first area  910   b  from five to two. According to an embodiment, the electronic device may determine the number of objects to be output on the display in consideration of the priority between the plurality of objects. For example, the electronic device may select the first object  911   b  and the fifth object  915   b , which are two objects having the highest priority among a plurality of objects displayed in the first area  910   b , and then may display the first object  911   b  and the fifth object  915   b  in the first area  910   b . In the same way, the electronic device may display only a sixth object  921   b  in a second area  920   b . According to an embodiment, the electronic device may reduce the number of objects displayed in the second area  920   b  from three to one. The electronic device may select the sixth object  921   b , which is an object having the highest priority among a plurality of objects displayed in the second area  920   b , and then may display the sixth object  921   b  in the second area  920   b.    
     According to an embodiment, the electronic device may increase the size of the object displayed in the first area  910   b  or the second area  920   b . According to an embodiment, the electronic device may reduce the amount of information thus provided by reducing the number of objects output on the display and increasing sizes of output objects, thereby providing improved visibility. The electronic device may reduce the amount of information provided on a screen and may increases the visibility of information, thereby reducing a speed at which the user&#39;s eye fatigue is accumulated. 
     Hereinafter, a method, in which an electronic device according to an embodiment changes an activated FOV depending on a user&#39;s eye fatigue level, will be described with reference to  FIG. 10 . 
       FIG. 10  is a diagram  1000  for describing an operation of changing an FOV of an electronic device, according to an embodiment. An electronic device  1001  according to an embodiment shown in  FIG. 10  may be the electronic device  401  of  FIG. 4 . Operations of the electronic device  1001  described below may be performed by the processor  430  of the electronic device  401 . 
     According to an embodiment, a camera module (e.g., the camera module  411  of  FIG. 4 ) of the electronic device  1001  may recognize a specific range based on a user&#39;s gaze direction  1011  when user wears the electronic device  1001 . The range may be referred to as a field of view (FOV). According to an embodiment, the electronic device  1001  may determine the gaze direction  1011  of the user by using a camera (e.g., the eye tracking camera  313  in  FIG. 3 ) that detects and tracks the location or movement of the user&#39;s eye or pupil. According to an embodiment, the electronic device  1001  may determine the gaze direction  1011  of the user based on a reference point  1010 . According to an embodiment, the reference point  1010  may be at least part of the electronic device  1001  corresponding to a center of both eyes of the user. For example, when the electronic device  1001  (e.g., the electronic device  201  of  FIG. 2 ) is a pair of glasses, the reference point  1010  may include a center of a bridge (e.g., the bridge  209  of  FIG. 2 ) connecting a first portion of a frame (e.g., the frame  203  in  FIG. 2 ), which surrounds a display (e.g., the first display  211 ) corresponding to a right eye, and a second portion of the frame (e.g., the frame  203  in  FIG. 2 ) surrounding a display (e.g., the second display  213 ) corresponding to a left eye. 
     According to an embodiment, the FOV recognized by the camera module of the electronic device  1001  may include a range that is horizontally spread by an arbitrary angle θ based on the gaze direction  1011  (0≤θ≤θ t ). For example, θ t  may mean the maximum angle corresponding to the maximum FOV recognizable by a camera module. 
     According to an embodiment, the electronic device may recognize objects within the 
     FOV recognized by the camera module. According to an embodiment, objects within the FOV recognized by the camera module may include real objects. According to an embodiment, the electronic device may provide information associated with the real object by overlapping a virtual object and the real object located within the FOV and displaying the overlapped result on a display. According to an embodiment, even though there is a virtual object mapped onto the actual object located out of FOV, the electronic device may omit the display of the virtual object or may display an alternative object. 
     According to an embodiment, as an eye fatigue level increases, the electronic device may reduce the FOV recognized by the camera module. According to an embodiment, as the FOV decreases, the number of objects located within the FOV may decrease. According to an embodiment, the electronic device displays a virtual object while the virtual object overlaps only an object located within the FOV. Accordingly, the amount of information displayed through a display may be reduced as the FOV decreases. As the eye fatigue level increases, the electronic device may reduce the FOV. Accordingly, the electronic device may reduce an amount of information provided to the user and may reduce the speed at which the user&#39;s eye fatigue is accumulated. 
     In the above-described embodiment, it is described that the electronic device reduces the FOV recognized by the camera module as the eye fatigue level increases, but an embodiment is not limited thereto. According to an embodiment, the electronic device may display information (e.g., a virtual object) about a specified FOV among FOVs recognized by the camera module. As the eye fatigue level increases, the electronic device may decrease a range of a specified FOV for displaying the information. 
     Hereinafter, a method in which an electronic device according to an embodiment constructs a screen depending on a user&#39;s eye fatigue level and a method in which an electronic device changes a constructed screen depending on a user interaction will be described with reference to  FIG. 11 . 
       FIG. 11  is a diagram  1100  illustrating a screen displayed on a display as an electronic device changes a FOV, according to an embodiment. Operations of an electronic device to be described below may be performed by the electronic device  1001  of  FIG. 10  (e.g., the electronic device  401  of  FIG. 4 ) or a processor (e.g., the processor  430  of  FIG. 4 ) of the electronic device  1001 .  FIG. 11  illustrates screens displayed on a display (e.g., the display  420  of  FIG. 4 ) of an electronic device. 
     In a first state  1101 , the electronic device may identify an eye fatigue level and may set a first FOV depending on the identified eye fatigue level. For example, the first FOV may include a range horizontally spread by θ 1  based on a user&#39;s gaze direction  1111 . The electronic device may recognize first objects  1115   a ,  1115   b ,  1115   c ,  1115   d ,  1115   e , and  1115   f , which are positioned within the first FOV. For example, the first objects  1115   a ,  1115   b ,  1115   c ,  1115   d ,  1115   e , and  1115   f  may include real objects present outside the electronic device. The electronic device may identify the first objects  1115   a ,  1115   b ,  1115   c ,  1115   d ,  1115   e , and  1115   f . Then, the electronic device may overlap second objects  1110   a ,  1110   b ,  1110   c ,  1110   d ,  1110   e , and  1110   f , which are mapped onto the first object  1115   a ,  1115   b ,  1115   c ,  1115   d ,  1115   e , and  1115   f , with the first object  1115   a ,  1115   b ,  1115   c ,  1115   d ,  1115   e , and  1115   f  and then may display the overlapped result. According to an embodiment, the second objects  1110   a ,  1110   b ,  1110   c ,  1110   d ,  1110   e , and  1110   f  may each be a virtual object, and may include information associated with the first objects  1115   a ,  1115   b ,  1115   c ,  1115   d ,  1115   e , and  1115   f . For example, when the first objects  1115   a ,  1115   b ,  1115   c ,  1115   d ,  1115   e , and  1115   f  are products for sale, the second objects  1110   a ,  1110   b ,  1110   c ,  1110   d ,  1110   e , and  1110   f  may include price information. 
     In a second state  1102 , the electronic device may identify an eye fatigue level, and may set a second FOV depending on the identified eye fatigue level. Hereinafter, it is assumed that the eye fatigue level identified in the second state  1102  is higher than the eye fatigue level identified in the first state  1101 . For example, the second FOV may include a range horizontally spread by θ 2  based on the user&#39;s gaze direction  1111 . According to an embodiment, as the eye fatigue level increases, the electronic device may decrease the FOV, and thus θ 2  may be smaller than θ 1 . The electronic device may recognize the first objects  1115   a ,  1115   b , and  1115   c , which are positioned within the second FOV. The electronic device may identify the first objects  1115   a ,  1115   b , and  1115   c . Then, the electronic device may overlap the second objects  1110   a ,  1110   b , and  1110   c , which are mapped onto the first object  1115   a ,  1115   b , and  1115   c , with the first object  1115   a ,  1115   b , and  1115   c  and then may display the overlapped result. The electronic device may identify the third objects  1115   d ,  1115   e , and  1115   f  positioned out of the second FOV. The electronic device may overlap fifth objects  1120   d ,  1120   e , and  1120   f , onto which an operation of outputting a fourth object (e.g.,  1110   d ) mapped onto the third objects  1115   d ,  1115   e , and  1115   f  is mapped, with the first objects  1115   a ,  1115   b , and  1115   c  and then may display the overlapped result. According to an embodiment, the fourth object may be a virtual object and may include information associated with the third objects  1115   d ,  1115   e , and  1115   f . According to an embodiment, the fifth objects may include virtual objects indicating that information (e.g., the fourth object) is capable of being displayed by a user interaction without directly displaying information (e.g., the fourth object). According to an embodiment, the operation of outputting the fourth object (e.g.,  1110   d ) may be mapped onto the fifth objects  1120   d ,  1120   e , and  1120   f . The electronic device may output the fourth object  1110   d  as the electronic device receives an input for selecting the fifth object  1120   d.    
     According to an embodiment, the electronic device may recognize a pointing object  1121  for pointing to an object output on a screen and a direction, in which the pointing object  1121  points, by using a camera module (e.g., the camera module  411  in  FIG. 4 ). The electronic device may select at least one object based on a direction pointed by the pointing object  1121 . For example, the electronic device may select the fifth object (e.g.,  1120   d ) based on the direction in which the pointing object  1121  points. The electronic device may receive a user input for selecting the fifth object (e.g.,  1120   d ). For example, the user input for selecting the fifth object may include a gesture input such as a gesture pointing to the fifth object by using the pointing object  1121 . 
     in a third state  1103 , the electronic device may output the fourth object  1110   d  as the electronic device receives a user input for selecting the fifth object (e.g.,  1120   d ). According to an embodiment, the electronic device may selectively display information by an additional user interaction without displaying information associated with the third objects  1115   d ,  1115   e , and  1115   f  positioned out of the second FOV. 
     Hereinafter, a method in which an electronic device according to an embodiment manages data associated with eye fatigue will be described with reference to  FIG. 12 . 
       FIG. 12  is a flowchart  1200  illustrating an operating method of an electronic device, according to an embodiment. Operations of an electronic device to be described below may be performed by an electronic device (e.g., the electronic device  401  of  FIG. 4 ) or a processor (e.g., the processor  430  of  FIG. 4 ) of the electronic device according to an embodiment. 
     In operation  1201 , the electronic device may identify a setting item that is changed in each mode. According to an embodiment, the electronic device may have a plurality of modes for changing at least one of a setting of a display or an output setting of content depending on an eye fatigue level. For example, a setting item related to the setting of the display may include at least one of brightness and scan rate of the display. A setting item related to the output setting of the content may include at least one of the number, sizes, locations, colors, or stereoscopic effect levels of objects output to the display. According to an embodiment, the setting item changed by the electronic device may be different for each mode. According to an embodiment, the electronic device may identify a setting item to be changed in each mode and a method in which a setting is changed for each item (e.g., the amount of change in a setting value for each item). For example, in a first mode, the electronic device may store a history of reducing the brightness of the display from eight to five in a memory (e.g., the memory  440  in  FIG. 4 ). 
     In operation  1203 , the electronic device may calculate the amount of change in the eye fatigue level according to a change in the setting item. The electronic device may calculate the amount of change in the eye fatigue level according to the change in the setting item by comparing the eye fatigue level, which is identified before the setting item is changed, with the eye fatigue level identified after the setting item is changed. 
     According to an embodiment, the eye fatigue level may increase in proportion to the usage time of the electronic device or the amount of content viewed by the user. For example, as compared to the usage time of the electronic device, the electronic device may reduce the speed, at which the eye fatigue level increases, by changing the setting item. For example, when the electronic device maintains an existing setting state, the eye fatigue level may increase by 3 after a specific time has elapsed. However, as the electronic device changes the setting state, the eye fatigue level identified after the same time has elapsed may increase by 1. According to an embodiment, as the change in the eye fatigue level is small, the change in the setting item is effective in reducing the user&#39;s eye fatigue. 
     According to an embodiment, together with change information including the changed setting item and the amount of change in a setting value, the electronic device may store the predicted amount of change in the eye fatigue level corresponding to the change information in the memory. 
     In operation  1205 , the electronic device may identify and store a setting item corresponding to the smallest amount of change in the eye fatigue level. According to an embodiment, the electronic device may identify change information corresponding to the smallest amount of change in the eye fatigue level among the stored change amount information of the eye fatigue level. The electronic device may separately store the identified change information (e.g., the changed setting item and the amount of change in a setting value) in a user database of the electronic device. 
     According to an embodiment, the user database may store an eye fatigue reducing method optimized for the user identified by the electronic device. According to an embodiment, the electronic device may change a setting item changed depending on the eye fatigue level and a setting value of the setting item based on data stored in the user database, thereby applying the eye fatigue reducing method optimized for the user. 
     According to an embodiment disclosed in the specification, an electronic device (e.g., the electronic device  101  of  FIG. 1 , the electronic device  201  of  FIG. 2 , the electronic device  301  of  FIG. 3 , the electronic device  401  of  FIG. 4 , or the electronic device  1001  of  FIG. 10 ) may include a camera module (e.g., the camera module  180  of  FIG. 1 , or the camera module  411  of  FIG. 4 ), a display (e.g., the display module  160  of  FIG. 1  or the display  420  of  FIG. 4 ) that displays AR content or VR content including at least one object, at least one processor (e.g., the processor  120  of  FIG. 1  or the processor  430  of  FIG. 4 ) operatively connected to the camera module and the display, and a memory (e.g., the memory  130  of  FIG. 1  or the memory  440  of  FIG. 4 ) operatively connected to the at least one processor and storing the AR content or VR content. The memory may store one or more instructions that, when executed, cause the at least one processor to obtain eye tracking data by using the camera module, to determine an eye fatigue level based on the eye tracking data, and to select one mode between a first mode for changing a setting of the display and a second mode for changing both the setting of the display and an output setting of the AR content or VR content, depending on the eye fatigue level. 
     According to an embodiment disclosed in the specification, the eye tracking data may include a measurement value for each of a plurality of parameters. The plurality of parameters may include at least one of an eye flicker frequency, a pupil adjustment speed, a degree of eye dryness, a degree of eye redness, or a degree of pupil tremor. 
     According to an embodiment disclosed in the specification, the instructions may cause the processor to obtain the eye tracking data at a specified period. 
     According to an embodiment disclosed in the specification, the instructions may cause the processor to identify an initial value of the eye tracking data, to calculate an amount of change by comparing the obtained eye tracking data with the initial value of the eye tracking data, and to determine the eye fatigue level depending on the amount of change. 
     According to an embodiment disclosed in the specification, the initial value may include an average value during a specified time period, an average value determined based on history information of a user of the electronic device, or a predetermined setting value. 
     According to an embodiment disclosed in the specification, the electronic device may further include a communication module (e.g., the communication module  190  of  FIG. 1 ). The instructions may cause the processor to identify a user of the electronic device, to receive setting information and usage history information of an external electronic device of the user, through the communication module, and to determine the initial value based on the setting information and the usage history information. 
     According to an embodiment disclosed in the specification, the instructions may cause the processor to identify a weight for each of the plurality of parameters, to apply the weight to at least one parameter among the plurality of parameters, and to determine whether the measurement value satisfies a condition for determining the eye fatigue level. The condition may include the at least one parameter or a combination of at least two parameters. 
     According to an embodiment disclosed in the specification, the electronic device may further include a sensor module (e.g., the sensor module  176  of  FIG. 1  or the sensor module  413  of  FIG. 4 ). The instructions may cause the processor to obtain a biometric signal by using the sensor module and to determine the eye fatigue level further based on the biometric signal. The biometric signal may include at least one of electrocardiogram (ECG) or electro-encephalography (EEG). 
     According to an embodiment disclosed in the specification, the instructions may cause the processor to determine the eye fatigue level further based on usage history information of the electronic device. The usage history information may include at least one of a usage time of the electronic device, the setting of the display, or a type of an application being executed. 
     According to an embodiment disclosed in the specification, the instructions may cause the processor to select the first mode when the eye fatigue level is greater than or equal to a first threshold value and is less than a second threshold value and to select the second mode when the eye fatigue level is greater than or equal to the second threshold value. 
     According to an embodiment disclosed in the specification, a first item associated with the setting of the display may include at least one of a scan rate or brightness. 
     According to an embodiment disclosed in the specification, a second item associated with the output setting of the AR content or the VR content may include at least one of a number, sizes, locations, colors, or stereoscopic effect levels of objects output to the display. 
     According to an embodiment disclosed in the specification, the instructions may cause the processor to reduce a field of view (FOV) recognized by the camera module as the eye fatigue level increases. 
     According to an embodiment disclosed in the specification, the instructions may cause the processor to output a second virtual object mapped onto a first real object positioned within the FOV and to output a fifth virtual object onto which an operation of outputting a fourth virtual object mapped onto a third real object positioned out of the FOV is mapped. 
     According to an embodiment disclosed in the specification, the instructions may cause the processor to output the fourth virtual object when a user input selecting the fifth virtual object is received. 
     According to an embodiment disclosed in the specification, the instructions may cause the processor to adjust the eye fatigue level based on the AR content or the VR content to be output on the display. 
     According to an embodiment disclosed in the specification, a method for operating an electronic device for displaying content may include obtaining eye tracking data by using a camera module, determining an eye fatigue level based on the eye tracking data, and selecting one mode between a first mode for changing a setting of a display and a second mode for changing both the setting of the display and an output setting of the content, depending on the eye fatigue level. 
     According to an embodiment disclosed in the specification, the selecting of the mode may include selecting the first mode when the eye fatigue level is greater than or equal to a first threshold value and is less than a second threshold value and selecting the second mode when the eye fatigue level is greater than or equal to the second threshold value. 
     According to an embodiment disclosed in the specification, a first item associated with the setting of the display may include at least one of a scan rate or brightness. 
     According to an embodiment disclosed in the specification, a second item associated with the output setting of the content may include at least one of a number, sizes, locations, colors, or stereoscopic effect levels of objects output to the display. 
     The electronic device according to various embodiments may be one of various types of electronic devices. The electronic devices may include, for example, a portable communication device (e.g., a smartphone), a computer device, a portable multimedia device, a portable medical device, a camera, a wearable device, or a home appliance. According to an embodiment of the disclosure, the electronic devices are not limited to those described above. 
     It should be appreciated that various embodiments of the disclosure and the terms used therein are not intended to limit the technological features set forth herein to particular embodiments and include various changes, equivalents, or replacements for a corresponding embodiment. With regard to the description of the drawings, similar reference numerals may be used to refer to similar or related elements. It is to be understood that a singular form of a noun corresponding to an item may include one or more of the things, unless the relevant context clearly indicates otherwise. As used herein, each of such phrases as “A or B,” “at least one of A and B,” “at least one of A or B,” “A, B, or C,” “at least one of A, B, and C,” and “at least one of A, B, or C,” may include any one of, or all possible combinations of the items enumerated together in a corresponding one of the phrases. As used herein, such terms as “1st” and “2nd,” or “first” and “second” may be used to simply distinguish a corresponding component from another, and does not limit the components in other aspect (e.g., importance or order). It is to be understood that if an element (e.g., a first element) is referred to, with or without the term “operatively” or “communicatively”, as “coupled with,” “coupled to,” “connected with,” or “connected to” another element (e.g., a second element), it means that the element may be coupled with the other element directly (e.g., wiredly), wirelessly, or via a third element. 
     As used in connection with various embodiments of the disclosure, the term “module” may include a unit implemented in hardware, software, or firmware, and may interchangeably be used with other terms, for example, “logic,” “logic block,” “part,” or “circuitry”. A module may be a single integral component, or a minimum unit or part thereof, adapted to perform one or more functions. For example, according to an embodiment, the module may be implemented in a form of an application-specific integrated circuit (ASIC). 
     Various embodiments as set forth herein may be implemented as software (e.g., the program  140 ) including one or more instructions that are stored in a storage medium (e.g., internal memory  136  or external memory  138 ) that is readable by a machine (e.g., the electronic device  101 ). For example, a processor (e.g., the processor  120 ) of the machine (e.g., the electronic device  101 ) may invoke at least one of the one or more instructions stored in the storage medium, and execute it, with or without using one or more other components under the control of the processor. This allows the machine to be operated to perform at least one function according to the at least one instruction invoked. The one or more instructions may include a code generated by a compiler or a code executable by an interpreter. The machine-readable storage medium may be provided in the form of a non-transitory storage medium. Wherein, the term “non-transitory” simply means that the storage medium is a tangible device, and does not include a signal (e.g., an electromagnetic wave), but this term does not differentiate between where data is semi-permanently stored in the storage medium and where the data is temporarily stored in the storage medium. 
     According to an embodiment, a method according to various embodiments of the disclosure may be included and provided in a computer program product. The computer program product may be traded as a product between a seller and a buyer. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read only memory (CD-ROM)), or be distributed (e.g., downloaded or uploaded) online via an application store (e.g., PlayStore™), or between two user devices (e.g., smart phones) directly. If distributed online, at least part of the computer program product may be temporarily generated or at least temporarily stored in the machine-readable storage medium, such as memory of the manufacturer&#39;s server, a server of the application store, or a relay server. 
     According to various embodiments, each component (e.g., a module or a program) of the above-described components may include a single entity or multiple entities, and some of the multiple entities may be separately disposed in different components. According to various embodiments, one or more of the above-described components may be omitted, or one or more other components may be added. Alternatively or additionally, a plurality of components (e.g., modules or programs) may be integrated into a single component. In such a case, according to various embodiments, the integrated component may still perform one or more functions of each of the plurality of components in the same or similar manner as they are performed by a corresponding one of the plurality of components before the integration. According to various embodiments, operations performed by the module, the program, or another component may be carried out sequentially, in parallel, repeatedly, or heuristically, or one or more of the operations may be executed in a different order or omitted, or one or more other operations may be added. 
     Certain of the above-described embodiments of the present disclosure can be implemented in hardware, firmware or via the execution of software or computer code that can be stored in a recording medium such as a CD ROM, a Digital Versatile Disc (DVD), a magnetic tape, a RAM, a floppy disk, a hard disk, or a magneto-optical disk or computer code downloaded over a network originally stored on a remote recording medium or a non-transitory machine readable medium and to be stored on a local recording medium, so that the methods described herein can be rendered via such software that is stored on the recording medium using a general purpose computer, or a special processor or in programmable or dedicated hardware, such as an ASIC or FPGA. As would be understood in the art, the computer, the processor, microprocessor controller or the programmable hardware include memory components, e.g., RAM, ROM, Flash, etc. that may store or receive software or computer code that when accessed and executed by the computer, processor or hardware implement the processing methods described herein. 
     While the present disclosure has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the present disclosure as defined by the appended claims and their equivalents.