Patent Publication Number: US-2022236566-A1

Title: Wearable device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit under 35 U.S.C. § 119(a) of Korean Patent Application No. 10-2021-0012365 filed on Jan. 28, 2021 in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes. 
     BACKGROUND 
     1. Field 
     The following description relates to a wearable device and, for example, a technology related to a secondary battery and a camera employed in a wearable device. 
     2. Description of Related Art 
     With the development of integrated circuit technology as well as display and battery technology, it has become possible to wear electronic devices as accessories in ways beyond simply carrying them. For example, smartwatches, smartglasses, and other items that have traditionally been in the realm of fashion or accessories have been manufactured to include processors, displays, and various sensors. 
     However, it is very important that a wearer not feel discomfort in daily life even if the wearer basically always wears the wearable device like clothes. For example, smartwatches are becoming more aesthetically pleasing and lightweight, like traditional wristwatches. If a wearable device is heavy or unpleasing in appearance, and the wearer is thus reluctant to use it, no matter how various and convenient functions the wearable device provides, the practical utility of the wearable device is inevitably low. 
     Since wearable devices may have a small size as compared with a smartphone, it may be difficult to insert a general battery in wearable devices. A battery using a liquid electrolyte has a high risk of electrolyte leakage, fire, and explosion. In particular, since wearable devices are often used in close contact with a user&#39;s body, safety devices are essential when using a liquid electrolyte battery, which has a negative effect on miniaturization of the battery. 
     In addition, due to the spatial limitations of the wearable devices, a space for mounting a camera in a wearable device may be insufficient, and even if a camera is mounted in the wearable device, the appearance of the wearable device may be negatively affected. 
     SUMMARY 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
     In one general aspect, a wearable device includes: a lens; a frame including a rim surrounding the lens and a temple extending from the rim; a reflection member altering a path of light incident from a side in front of the lens toward the lens; an image sensor collecting light reflected from the reflection member; and at least one camera lens disposed on a path of the light collected by the image sensor. 
     The reflection member may be at least partially disposed inside the rim, and the image sensor may be embedded in the frame. 
     The wearable device may further include at least one electronic component electrically connected to the image sensor and embedded in the temple. 
     The temple may be foldably coupled to the rim, the image sensor may be electrically connected to the at least one electronic component, and the at least one electronic component may be embedded in the temple through a flexible board. 
     The reflection member may be a part of the lens. 
     The lens may include a reflection surface configured to alter a path of light toward the image sensor. 
     The glass lens may further include a recess at least partially defined by the reflection surface. 
     The reflection member and the image sensor may be embedded in the rim. 
     The rim may include two rims, and the frame may further include a bridge connecting of the two rims. Any one or any combination of any two or more of the reflection member, the lens, and the image sensor may be embedded in the bridge. 
     The wearable device may further include a light guide prism. The light guide prism may be configured to reflect light incident to the light guide prism at least twice inside the light guide prism. 
     The wearable device may further include a wide-angle lens disposed on an object side of the reflection member. 
     The wearable device may further include: electronic components; and solid-state batteries configured to supply power to the electronic components. 
     Each of the solid-state batteries may include: a cathode; an anode; a body including a solid electrolyte layer disposed between the cathode and the anode; and a first external electrode and a second external electrode, the first external electrode being disposed on one surface of the body and connected to the cathode, and the second external electrode being disposed on another surface of the body opposite to the one surface of the body and connected to the anode. 
     The wearable device may further include battery cells each including at least one of the solid-state batteries. The battery cells may be configured to supply power to the electronic components, respectively. 
     The wearable device may further include a power manager electrically connected to the battery cells. The power manager may be configured to selectively discharge a battery cell among the battery cells that is allocated to an activated electronic component among the electronic components. 
     The wearable device may further include a power manager electrically connected to the battery cells. The power manager may be configured to preferentially charge a battery cell, among the battery cells, that has a low state of charge over a battery cell, among the battery cells, that has a high state of charge. 
     The wearable device may further include: a power manager electrically connected to the solid-state batteries; a main processor; and a lithium ion battery. The power manager may be configured to determine whether to discharge the lithium ion battery based on whether the main processor is activated. 
     In another general aspect, a wearable device includes: a lens; a frame surrounding the lens; a temple extending from the frame; electronic components; battery cells configured to supply power to the electronic components, respectively, each of the battery cells including at least one solid-state battery; and a power manager configured to selectively discharge a battery cell among the battery cells that is allocated to an activated electronic component among the electronic components. 
     The electronic components, the battery cells, and the power manager may be disposed in the temple. 
     The wearable device may further include a camera disposed in the frame. A battery cell, among the battery cells, may be configured to supply power to the camera. 
     The wearable device may further include a main battery. The power manager may be further configured to selectively discharge the main battery to charge a battery cell among the battery cells. 
     The power manager may be further configured to preferentially charge a battery cell, among the battery cells, that has a low state of charge over a battery cell, among the battery cells, that has a high state of charge. 
     The wearable device may further include: a main processor; and a main battery. The power manager may be further configured to determine whether to discharge the main battery based on whether the main processor is activated. 
     Other features and aspects will be apparent from the following detailed description, the drawings, and the claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  illustrates a wearable device, according to an embodiment. 
         FIG. 2  is a block diagram illustrating components included in the wearable device, according to an embodiment. 
         FIG. 3  illustrates a board disposed in a temple and electronic components mounted on the board, according to an embodiment. 
         FIG. 4  illustrates connection between a plurality of solid-state batteries and the electronic component, according to an embodiment. 
         FIG. 5  illustrates the solid-state battery, according to an embodiment. 
         FIG. 6  is a cross-sectional view taken along line I-I′ of  FIG. 5 . 
         FIG. 7  is a block diagram illustrating power management using the solid-state battery, according to an embodiment. 
         FIG. 8  is a flowchart illustrating a discharge of the solid-state battery corresponding to a used device, according to an embodiment. 
         FIG. 9  is a flowchart illustrating a charge of the solid-state battery based on a state of charge, according to an embodiment. 
         FIG. 10  is a flowchart illustrating selective use of a main battery based on an operation state of a processor, according to an embodiment. 
         FIG. 11  illustrates a circuit supplying power to the processor, according to an embodiment. 
         FIG. 12  is a flowchart illustrating a power supply method in which the main battery is used to assist the solid-state battery, according to an embodiment. 
         FIG. 13  illustrates first and second cameras mounted on the wearable device, according to an embodiment. 
         FIG. 14  illustrates a hinge connecting a rim and a temple of the wearable device, according to an embodiment. 
         FIG. 15A  illustrates a state in which a portion of a glass lens functions as a reflection member, according to an embodiment. 
         FIG. 15B  illustrates a state in which a portion of the glass lens functions as the reflection member, according to an embodiment. 
         FIG. 16A  is a cross-sectional view taken along line II-II′ of  FIG. 15A . 
         FIG. 16B  is a cross-sectional view taken along line III-III′ of  FIG. 15B . 
         FIG. 17  illustrates a state in which the first camera is disposed in an upper portion of the rim, according to an embodiment. 
         FIG. 18  illustrates a state in which the first camera is disposed at a bridge of the wearable device, according to an embodiment. 
         FIG. 19  illustrates a state in which two cameras are disposed on the bridge of the wearable device, according to an embodiment. 
         FIGS. 20A through 20D  illustrate various forms of a light guide prism, according to an embodiment. 
         FIG. 21  illustrates a lens additionally provided on the reflection member of the first camera, according to an embodiment. 
         FIG. 22  illustrates a state in which a subject positioned behind a wearer of the wearable device is displayed, according to an embodiment. 
         FIG. 23  illustrates gesture recognition using the wearable device, according to an embodiment. 
         FIG. 24  illustrates a state in which users located in different places share fields of view with each other, according to an embodiment. 
         FIG. 25  illustrates a keyboard input using a gaze of the wearer, according to an embodiment. 
         FIG. 26  illustrates a driver wearing the wearable device and a field of view of the driver, according to an embodiment. 
     
    
    
     Throughout the drawings and the detailed description, the same reference numerals refer to the same elements. The drawings may not be to scale, and the relative size, proportions, and depiction of elements in the drawings may be exaggerated for clarity, illustration, and convenience. 
     DETAILED DESCRIPTION 
     The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatuses, and/or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatuses, and/or systems described herein will be apparent after an understanding of the disclosure of this application. For example, the sequences of operations described herein are merely examples, and are not limited to those set forth herein, but may be changed as will be apparent after an understanding of the disclosure of this application, with the exception of operations necessarily occurring in a certain order. Also, descriptions of features that are known in the art may be omitted for increased clarity and conciseness. 
     The features described herein may be embodied in different forms, and are not to be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many possible ways of implementing the methods, apparatuses, and/or systems described herein that will be apparent after an understanding of the disclosure of this application. 
     Throughout the specification, when an element, such as a layer, region, or substrate, is described as being “on,” “connected to,” or “coupled to” another element, it may be directly “on,” “connected to,” or “coupled to” the other element, or there may be one or more other elements intervening therebetween. In contrast, when an element is described as being “directly on,” “directly connected to,” or “directly coupled to” another element, there can be no other elements intervening therebetween. 
     Herein, it is to be noted that use of the term “may” with respect to an embodiment or example, e.g., as to what an embodiment or example may include or implement, means that at least one embodiment or example exists in which such a feature is included or implemented while all examples and examples are not limited thereto. 
     As used herein, the term “and/or” includes any one and any combination of any two or more of the associated listed items. 
     Although terms such as “first,” “second,” and “third” may be used herein to describe various members, components, regions, layers, or sections, these members, components, regions, layers, or sections are not to be limited by these terms. Rather, these terms are only used to distinguish one member, component, region, layer, or section from another member, component, region, layer, or section. Thus, a first member, component, region, layer, or section referred to in examples described herein may also be referred to as a second member, component, region, layer, or section without departing from the teachings of the examples. 
     Spatially relative terms such as “above,” “upper,” “below,” and “lower” may be used herein for ease of description to describe one element&#39;s relationship to another element as shown in the figures. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, an element described as being “above” or “upper” relative to another element will then be “below” or “lower” relative to the other element. Thus, the term “above” encompasses both the above and below orientations depending on the spatial orientation of the device. The device may also be oriented in other ways (for example, rotated 90 degrees or at other orientations), and the spatially relative terms used herein are to be interpreted accordingly. 
     The terminology used herein is for describing various examples only, and is not to be used to limit the disclosure. The articles “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “includes,” and “has” specify the presence of stated features, numbers, operations, members, elements, and/or combinations thereof, but do not preclude the presence or addition of one or more other features, numbers, operations, members, elements, and/or combinations thereof. 
     Due to manufacturing techniques and/or tolerances, variations of the shapes shown in the drawings may occur. Thus, the examples described herein are not limited to the specific shapes shown in the drawings, but include changes in shape that occur during manufacturing. 
     The features of the examples described herein may be combined in various ways as will be apparent after an understanding of the disclosure of this application. Further, although the examples described herein have a variety of configurations, other configurations are possible as will be apparent after an understanding of the disclosure of this application. 
     An electronic device according to various embodiments herein may include at least one of, for example, a smartphone, a tablet personal computer (PC), a mobile phone, a video phone, an e-book reader, a desktop PC, a laptop PC, a netbook computer, a workstation, a server, a personal digital assistant (PDA), a portable multimedia player (PMP), an MP3 player, a mobile medical device, a camera, or a wearable device. According to various embodiments, the wearable device may include at least one of an accessory-type device (for example, a watch, a ring, a bracelet, an anklet, a necklace, glasses, contact lenses, or a head-mounted device (HMD)), a fabric- or clothes-integrated device (for example, electronic clothes), a body attached-type device (for example, a skin pad or tattoo), or an implantable device (for example, an implantable circuit). 
     Hereinafter, the electronic device according to an embodiment in the present disclosure will be described in detail with reference to the accompanying drawings. 
     Overall Configuration of Wearable Device 
       FIG. 1  illustrates a wearable device  1 , according to an embodiment.  FIG. 2  is a block diagram illustrating components included in the wearable device  1 , according to an embodiment. 
     The wearable device  1  may have a form of smartglasses, but is not limited thereto. Some or all of the components described herein may be applied to a wearable device having a different form according to another embodiment as well. 
     The wearable device  1  may have a form that a user can wear, such as glasses. The wearable device  1  may include a glass lens  130  disposed in front of the eyes of the user and a frame  105  to which the glass lens  130  is coupled. In this disclosure, the glass lens  130  may be referred to as a glass lens in order to distinguish the glass lens  130  from a first lens  151  and a second lens of first and second cameras  150  and  160 , respectively. However, the glass lens  130  is not limited to being made of a glass material and may be made of a polymer material, for example. The frame  105  of the wearable device  1  may include two rims  110  accommodating the glass lens  130  and a bridge  120  connecting the two rims  110 . The wearable device  1  may further include a temple  140  extending from the rim  110  and configured to be hung or otherwise supported on the ear of the wearer. 
     Herein, unless described otherwise, a side in front of the wearable device  1  or the glass lens  130  means a direction (that is, −X direction) in which a field of view of the wearer is directed when the wearer wears the wearable device  1 , and a side behind the wearable device  1  or the glass lens  130  means a direction (that is, +X direction) opposite to the direction in which the field of view of the wearer is directed when the wearer wears the wearable device  1 . Further, a lateral side of the wearable device  1  means the left side or the right side (that is, +Y or −Y direction). 
     According to an embodiment, the wearable device  1  may include at least one lens, an image sensor, and a reflection member configured to change a path of incident light toward the image sensor. The reflection member may be a part of the glass lens  130  or may be a member such as a prism or a mirror independent of the glass lens  130 . According to an embodiment, the image sensor may be disposed inside the frame  105 . For example, the image sensor may be embedded in the rim  110  surrounding the glass lens  130 . According to an embodiment, the image sensor may be oriented in a direction orthogonal or substantially orthogonal to a direction in which the glass lens  130  is oriented. For example, referring to  FIG. 1 , the glass lens  130  may have a light transmission surface facing the X direction, and a first image sensor  152  may have an image sensing plane facing the −Y direction. A second image sensor  162  may have an image sensing plane facing a +Z direction. A first reflection member  153  may be configured to make a path of light incident toward the eye of the user from the glass lens  130  (that is, in the +X direction) be directed in the Y direction. A second reflection member  163  may be configured to make a path of light incident toward the glass lens  130  from the eye of the user (that is, in the &#39; 1 X direction) be directed in the Z direction. According to an embodiment, a plurality of lenses may be arranged between the first or second reflection member  153  or  163  and the first or second image sensor  152  or  162 , respectively. The plurality of lenses may be arranged in a direction orthogonal or substantially orthogonal to the direction in which the glass lens  130  is oriented. According to an embodiment, the wearable device  1  may include one or more cameras, for example, a first camera  150  and a second camera  160 . According to an embodiment, the first camera  150  may include at least one first lens  151  configured to refract light, and the image sensor  152 . The first camera  150  may further include the first reflection member  153 . According to an embodiment, the second camera  160  may include at least one second lens configured to refract light, and the image sensor  162 . The second camera  160  may further include the second reflection member  163 . According to an embodiment, the first and second image sensors  152  and  162  may include any one or any combination of any two or more of a color image sensor, a monochrome image sensor, an ultraviolet sensor, an infrared sensor, and a thermal imaging sensor. According to an embodiment, the first and second cameras  150  and  160  may be configured to collect light incident through a part of a region surrounded by the rim  110 . The first or second reflection member  153  or  163  may be at least partially disposed in the rim  110  and may be visually recognized when the wearable device  1  is viewed from the side in front of the wearable device  1 . For example, a reflection surface of the first or second reflection member  153  or  163  may be disposed in the region surrounded by the rim  110 . That is, a part of light passing through the inside of the rim  110  may enter into the first camera  150  or the second camera  160  through the first reflection member  153  or the second reflection member  163 . According to an embodiment, the reflection surface (for example, a reflection surface  141  of  FIG. 15A ) configured to change a path of light is at least partially positioned inside the rim  110  when the wearable device  1  is viewed from the side in front of the wearable device  1  (that is, when viewed in the X direction). For example, referring to  FIG. 1 , the first or second reflection member  153  or  163  may be at least partially positioned inside the rim  110  when the wearable device  1  is viewed from the side in front of the wearable device  1  (that is, when viewed in the X direction). According to an embodiment, the first or second camera  150  or  160  may be at least partially accommodated in the frame  105 . According to an embodiment, any one or any combination of any two or more of the at least one lens first lens  151 , the at least one second lens, the image first image sensor  152 , the second image sensor  162 , the first reflection member  153 , and the second reflection member  163  may be accommodated in the rim  110 . 
     According to an embodiment, the first or second camera  150  or  160  may provide an image stabilization function or an automatic focusing function by moving, instead of the first lens  151  or the second lens, the first or second image sensor  152  or  162  in a direction orthogonal to an optical axis or an optical axis direction. An actuator configured to move the first or second image sensor  152  or  162  may include, for example, a voice coil motor, a shape memory alloy wire, a piezoelectric element, or the like. 
     According to an embodiment, the wearable device  1  may include the first camera  150  and the second camera  160  disposed adjacent to the rim  110 . The first camera  150  may move along the head of the wearer and capture an image of a subject positioned in front of the wearer. In this disclosure, the first camera  150  may be referred to as a head tracking camera. According to an embodiment, the second camera  160  may capture an image of the eye of the wearer and the wearable device  1  may determine a direction or a point to which the gaze of the wearer is directed by using the second camera  160 . In this disclosure, the second camera  160  may be referred to as an eye tracking camera. 
     According to an embodiment, the first or second camera  150  or  160  may include the first or second reflection member  153  or  163 . The first or second reflection member  153  or  163  may be configured to change a direction of light, and may be implemented by, for example, a prism or a mirror. As another example, the glass lens  130  may be partially machined to provide the reflection surface, and in this case, a portion of the glass lens  130  may provide a function similar to that of the first or second reflection member  153  or  163 . A more detailed description of the reflection surface of the glass lens  130  will be provided with reference to  FIGS. 15A to 16B . 
     Since the first or second camera  150  or  160  includes the first or second reflection member  153  or  163 , the first or second image sensor  152  or  162  need not be oriented in a direction in which image capturing is to be performed. That is, the first or second image sensor  152  or  162  may be oriented in various directions, and thus, the wearable device  1  may secure a sufficient degree of freedom in installing the camera. As a result, a camera having an excellent performance may be provided without impairing an appearance of the wearable device  1 . 
     According to an embodiment, the first reflection member  153  of the first camera  150  may reflect, toward the first image sensor  152 , light incident toward the wearer from the side in front of the wearable device  1 . As a result, an imaging surface  152   a  of the first image sensor  152  of the first camera  150  is not required to be oriented toward the side in front of the wearable device  1 , and may be oriented in various directions according to design convenience. For example, in a case in which the first reflection member  153  changes a direction of light incident from the side in front of the wearable device  1  by 90 degrees, the first image sensor  152  may be oriented toward the lateral side of the wearable device  1 . Unless otherwise described herein, a direction in which the first image sensor  152  is oriented means a direction that the imaging surface  152   a  of the first image sensor  152  faces. 
     According to an embodiment, the second reflection member  163  of the second camera  160  may change, toward the second image sensor  162 , a direction of light reflected from the eye of the wearer. For example, the second image sensor  162  may be disposed so that an imaging surface  162   a  is oriented upwardly (that is, in the +Z direction). As a result, the imaging surface  162   a  of the second image sensor  162  of the second camera  160  is not required to be oriented toward the eye of the wearer, and may be oriented in various directions according to design convenience. For example, in a case in which the second reflection member  163  changes a direction of light incident from behind the rim  110  by 90 degrees, the second image sensor  162  may be oriented toward an upper side of the wearable device  1 . 
     According to an embodiment, one first camera  150  and one second camera  160  are provided at the rims  110 , respectively. However, this is only an example. According to another embodiment, only one first camera  150  or one second camera  160  may be provided at the left side or the right side. For example, the first camera  150  and the second camera  160  may be provided on the left side of the wearable device  1 , and the camera does not have to be disposed on the right side. 
     The positions at which the first camera  150  and the second camera  160  are disposed are not limited to those illustrated in the drawings. For example, the first camera  150  may be disposed at the bridge  120  of the wearable device  1 , as illustrated in  FIG. 18 or 19 . As another example, the first camera  150  may be disposed at a lower side of the rim  110 , rather than being disposed at the upper side of the rim  110 . 
     Referring to  FIGS. 2 and 3 , according to an embodiment, the wearable device  1  may include various electronic components (for example, a processor  181 , a memory  182 , and a battery  190  including a solid-state battery  191  and a lithium ion battery  193 , for example). At least some of the electronic components may be accommodated in the temple  140  of the wearable device  1 . For example, at least some of the electronic components may be embedded in the temple  140 . A board  141  may be accommodated in the temple  140  of the wearable device  1 , and the electronic components may be mounted on the board  141 . According to an embodiment, the first or second image sensor  152  or  162  may be electrically connected to at least one electronic component accommodated in the temple  140 . 
     For example, the processor  181  may control at least one different component (for example, a hardware component or software component) of the wearable device  1  that is connected to the processor  181  by executing software (for example, a program), and may perform various data processes or operations. According to an embodiment, as at least a part of the data processing or operation, the processor  181  may load a command or data received from another component (for example, a sensor module  184  (which may also be referred to as a sensor device  184 ) or a communication module  185  (which may also be referred to as a communicator  185 )) on the memory  182 , may process a command or data stored in the memory  182 , or may store result data in the memory  182 . According to an embodiment, as shown in  FIG. 2 , the processor  181  may include a main processor  181   a  (for example, a central processing unit (CPU) or an application processor), and an auxiliary processor  181   b  (for example, a graphics processing unit (GPU), an image signal processor, a sensor hub processor, or a communication processor) that may be operated independently of or in cooperation with the main processor  181   a . Additionally or alternatively, the auxiliary processor  181   b  may be set to use low power as compared with the main processor  181   a  or to be specialized for a specific function. The auxiliary processor  181   b  may be implemented independently of the main processor  181   a  or may be implemented as a part of the main processor  181   a.    
     The auxiliary processor  181   b  may control at least some of functions or states related to at least one (for example, a display device  170 , the sensor module  184 , or the communication module  185 ) of the components of the wearable device  1 , instead of the main processor  181   a  while the main processor  181   a  is in an inactive state (for example, a sleep state), or in cooperation with the main processor  181   a  while the main processor  181   a  is in an active state (for example, an application execution state). According to an embodiment, the auxiliary processor  181   b  (for example, an image signal processor  181  or a communication processor  181 ) may be implemented as a part of another functionally related component (for example, the first or second camera module  150  or  160  or the communication module  185 ). 
     The memory  182  may store various data used by at least one component (for example, the processor  181  or the sensor module  184 ) of the wearable device  1 . Examples of the data may include software (for example, a program) and input data or output data for a command related thereto. The memory  182  may include a volatile memory and/or a non-volatile memory. The program may be stored as the software in the memory  182 , and may include, for example, an operating system, a middleware, or an application. 
     According to an embodiment, the wearable device  1  may include an input device  183 , as shown in  FIG. 2 . The input device  183  may include, for example, a touch sensor, a microphone, and a camera. The wearer may touch a portion of a surface of the wearable device  1  to execute a corresponding function. For example, in a case of listening to music, the wearer may play or stop music by touch interaction. The wearer may make a voice call by using a microphone or may issue an instruction to an artificial intelligence (AI) assistant. 
     The sensor module  184  may detect an operation state (for example, power or temperature) of the wearable device  1  or an external environment state (for example, a state of the wearer) and generate an electric signal or data value corresponding to the detected state. According to an embodiment, for example, the sensor module  184  may include any one or any combination of any two or more of 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, an illuminance sensor, a position sensor, or a GPS sensor. 
     The display device  170  may provide information to the outside (for example, the wearer) of the electronic device in a visible manner. The display device  170  may include, for example, a display, a hologram device, or a projector, and a control circuit for controlling the corresponding device. 
     The display may be a device that displays various contents such as an image, a video, a text, and music, an application execution screen including various contents, a graphic user interface (GUI) screen, and the like. The display may be implemented in various forms such as a liquid crystal display (LCD), a light emitting diode (LED) display, an organic light emitting diode (OLED) display, liquid crystal on silicon (LCoS), digital light processing (DLP), a quantum dot (QD) display panel, a micro electromechanical systems (MEMS) display, and an electronic paper display, but is not limited thereto. 
     According to an embodiment, the display may be provided as a screen provided at the projector and the glass lens  130 . An image projected from the projector may be reflected by the screen and visually recognized by the wearer. According to an embodiment, a prism may be provided between the projector and the screen. Light emitted the projector may be reflected inside the prism and reach the screen. For example, the screen may be formed of a transparent material, such that the screen does not block a front view regardless of whether or not an image is displayed. According to another embodiment, a transparent display may be directly provided on one side of the glass lens  130 . For example, an OLED panel does not require a separate light source, and thus has a relatively high transmission. Therefore, the OLED panel is suitable for being provided on one side of the wearable device  1 . 
     According to an embodiment, the wearable device  1  may include the communication module  185 . The communication module  185  functions to connect the wearable device  1  to an external device. As a result, the wearable device  1  may receive various types of information required for driving the wearable device  1 , update information for updating of the wearable device  1 , or the like through the communication module  185 . The communication module  185  may perform communication with an external device by various communication methods. Accordingly, the communication module  185  may include various communication modules such as a short-range wireless communication module and a wireless communication module. 
     Here, the short-range wireless communication module is, for example, a communication module that performs wireless communication with an external device located within a short range, such as a Bluetooth module or a Zigbee module. The wireless communication module is, for example, a module that is connected to an external network to perform communication according to a wireless communication protocol such as Wi-Fi or IEEE. In addition, the wireless communication module may further include a mobile communication module that performs communication by accessing a mobile communication network according to various mobile communication standards such as 3 rd  generation (3G), 3 rd  generation partnership project (3GPP), long term evolution (LTE), and 5 th  generation (5G). 
     An interface  189  may support one or more specified protocols that may be used for direct or wireless connection between the wearable device  1  and an external device. According to an embodiment, the interface  189  may include, for example, a high definition multimedia interface (HDMI), a universal serial bus (USB) interface, an SD card interface, or an audio interface. The interface  189  may include a connector through which the wearable device  1  may be physically connected to an external device. According to an embodiment, the connector may include, for example, an HDMI connector, a USB connector, an SD card connector, or an audio connector (for example, a headphone connector). 
     An audio module  187  (which may also be referred to as an audio converter  187 ) may convert a sound into an electric signal or may convert an electric signal into a sound. According to an embodiment, the audio module  187  may obtain a sound through the input device (for example, a microphone), or may output a sound through an audio output device or an external wearable device  1  (for example, a speaker or headphone) directly or wirelessly connected to the wearable device  1 . 
     The audio output device may output an audio signal to the outside of the wearable device  1 . The audio output device may include, for example, a speaker or a receiver. The speaker may be used on general purpose such as reproduction of multimedia or playback, and the receiver may be used to receive an incoming call. According to an embodiment, the receiver may be implemented independently of the speaker or may be implemented as a part of the speaker. According to an embodiment, the audio output device may be disposed at the temple  140  of the wearable device  1  and may thus be positioned near the ear of the wearer when the wearer wears the wearable device  1 . 
     A haptic module  188  (which may also be referred to as a haptic device  188 ) may convert an electric signal into a mechanical stimulus (for example, vibration or motion) or an electrical stimulus that may be recognized by the wearer through tactile sensation or movement sensation. According to an embodiment, the haptic module  188  may include, for example, a motor, a piezoelectric element, or an electric stimulation device. 
     According to an embodiment, the wearable device  1  may include at least one solid-state battery  191 . The solid-state battery  191  may be a secondary battery to which a solid electrolyte is applied. A battery to which the solid electrolyte is applied has various advantages compared to a battery to which a liquid electrolyte is applied according to the related art. 
     A lithium ion battery mainly used in a smart device includes a cathode, an anode, and a liquid electrolyte as a medium through which electrons may move between the cathode and the anode. The lithium ion battery further includes a separator provided between the cathode and the anode to prevent a contact between the cathode and the anode. On the other hand, the solid-state battery  191  may include the solid electrolyte instead of the liquid electrolyte, and the solid electrolyte may also serve as the separator. 
     Since the current lithium ion battery uses the liquid electrolyte, there is a risk of battery damage such as battery expansion due to a temperature change or leakage due to an external shock, and components or devices are needed to increase safety. On the other hand, the solid-state battery including the solid electrolyte is structurally rigid and is thus stable, and even when the electrolyte is damaged, the shape of the solid-state battery may be maintained, which enables further improvement of the safety. 
     Further, the solid-state battery has a higher energy density than that of the existing lithium ion battery. This is because, as the risk of explosion or fire disappears, safety-related components are omitted and components (for example, a cathode active material or an anode active material) that can increase the capacity of the battery can be provided in the place of the safety-related components. 
     A battery to which a solid electrolyte is applied outputs high power for its size. Therefore, the solid-state battery  191  may have excellent output efficiency even when the size of the solid-state battery  191  is small. Therefore, the degree of freedom in designing the structure of the wearable device  1  may be greatly improved. For example, the wearable device  1  having a small size may have a battery with a sufficient capacity without impairing device performance or appearance by applying the solid-state battery  191 . 
     The solid-state battery  191  may remove an unstable transient response generated at the moment when power is supplied to the electronic component or power is cut off. In general, a voltage may be dropped or raised at the moment when a single battery supplies power to multiple electronic components and supplies power a specific electronic component, and at the moment when power is cut off, which may result in damage of the electronic component or the battery. On the other hand, according to an embodiment, the solid-state battery  191  may prevent or significantly suppress a phenomenon that a voltage is momentarily dropped (or raised), which may contribute to an increase in lifetime of the battery or the electronic component. 
     According to an embodiment, one or more solid-state batteries  191  may be combined as one battery cell (for example, a battery cell  192  of  FIG. 4 ) and supply power to a specific electronic component. The battery cell formed of the one or more solid-state batteries  191  may provide various output voltages or charge capacities according to a manner in which the solid-state batteries  191  are connected. 
     According to an embodiment, the solid-state batteries  191  may be divided into two or more battery cells supplying power to a plurality of electronic components independently of each other. According to an embodiment, the wearable device  1  may include various electronic components and a plurality of battery cells (for example, the battery cells  192  of  FIG. 7 ) that are allocated to the electronic components, respectively, and each include at least one solid-state battery  191 . The battery cells may have different charge capacities. In this disclosure, the charge capacity may be an electric capacity or a charge amount that the battery cell may have, and may be a nominal capacity at 25° C. and 1 atmospheric pressure. A battery cell having a large charge capacity may be connected to a component that consumes a large amount of power, thereby facilitating power management. 
     According to an embodiment, operating voltages of the battery cells may be different from each other. In this disclosure, the operating voltage may be an average operating voltage in a case of the battery cell being discharged at a room temperature and a normal pressure, and may be a nominal voltage at 25° C. and 1 atmospheric pressure. For example, a battery cell corresponding to a required voltage of the electronic component provided in the wearable device  1  may be provided according to a manner in which the solid-state batteries are combined, which may reduce power consumed in a power circuit or the like. 
     According to an embodiment, the battery cells may be designed to have an operating voltage optimized for an environment in which a specific component, such as a display, is used. For example, the operating voltage of the battery cell directly connected to the application program processor  181  (AP) may be relatively high, and a battery cell having a general operating voltage may be applied as a battery cell connected to a main board  141 . In this case, the degree of freedom in designing the structure of the wearable device  1  is increased, and a process such as altering a voltage is minimized to significantly improve efficiency in using electricity. 
     Different capacities or operating voltages of the battery cells may be implemented by varying the number of solid-state batteries  191  included in each battery cell or varying a connection form of the solid-state batteries  191 . For example, in a case in which multiple solid-state batteries  191  having the same specification are connected in series, an output voltage is increased. As another example, as the number of connected batteries is increased, the capacity of the cell is increased. 
       FIG. 3  illustrates the board  141  provided in the temple  140  and the electronic components mounted on the board  141  according to an embodiment. 
     Referring to  FIG. 3 , the wearable device  1  may include the board  141  in the temple  140 , and the battery cell  192  including one or more solid-state batteries  191  may be mounted on a surface of the board  141  and/or inside the board  141 . 
     According to an embodiment, the solid-state battery may be disposed in any region of the board  141 . For example, after the processor  181 , an antenna module, or the like, is appropriately arranged on the board, and the solid-state batteries  191  may be disposed in the remaining space. Since each of the solid-state batteries  191  has a relatively small size, the remaining space of the board  141  may be efficiently filled with the solid-state batteries  191 . Accordingly, the size of the temple  140  may be kept relatively small, and the wearable device  1  may receive power necessary for driving (for example, a camera function, a display function, or an audio function) of the wearable device  1  from the solid-state batteries  191 . 
     According to an embodiment, the solid-state battery  191  may be disposed around the electronic component to which the solid-state battery  191  is allocated. For example, the solid-state batteries  191  may be mounted on or inside the board  141  and supply power to the surrounding electronic components. 
     In general, since each electronic component using one battery, the circuit board  141 , and an electric wiring, and the like are connected, an impedance varies due to a parasitic component, and finally, a voltage supplied to the electronic component may be decreased. According to an embodiment, the solid-state battery  191  is disposed close to the electronic component, which may significantly reduce a voltage loss resulting from the parasitic component such as the electric wiring. 
       FIG. 4  illustrates connection between the plurality of solid-state batteries  191  and the electronic component, according to an embodiment. 
     Referring to  FIG. 4 , multiple solid-state batteries  191  may be connected in series and in parallel to form one battery cell  192 , and the battery cell  192  may supply power to the processor  181 . In the illustrated embodiment, eight solid-state batteries  191  are connected in series and in parallel and supply power to the processor  181 . The illustrated embodiment is only an example, and according to other embodiments, the number, a connection method, or a power supply target of the solid-state batteries  191  may vary. 
       FIG. 5  illustrates a solid-state battery  300 , according to an embodiment.  FIG. 6  is a cross-sectional view taken along line I-I′ of  FIG. 5 . The solid-state battery  300  illustrated in  FIGS. 5 and 6  is an example of the solid-state battery  191  described with reference to  FIGS. 1 through 4 . 
     Referring to  FIGS. 5 and 6 , the solid-state battery  300  may include: a body  310  including a solid electrolyte layer  311 ; a cathode  321  and an anode  322  disposed such that the solid electrolyte layer  311  is interposed between the cathode  321  and the anode  322 ; a first external electrode  331 ; and a second external electrode  332 . The first external electrode  331  is disposed on one surface of the body  310  and is connected to the cathode  321 . The second external electrode  332  is disposed on the other surface of the body  310  opposite to the one surface and connected to the anode  322 . 
     According to an embodiment, the solid-state battery  300  may be mounted on the board  141  by using a method such as soldering, laser fusion, ultrasonic fusion, or a solder paste method. For example, the solid-state battery  300  may be soldered ( 342 ) on the board  141  so that the first and second external electrodes  331  and  332  are attached to conductive pads  341  disposed on the board  141 . 
     In an example, a cathode active material contained in the cathode  321  is not particularly limited as long as a sufficient capacity may be secured. For example, the cathode active material may include any one or any combination of any two or more of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, and lithium manganese oxide, but is not limited thereto, and all cathode active materials available in the corresponding technical field may be used. 
     The cathode active material may be, for example, a compound expressed by the following chemical formulae: LiaAl-bMbD 2  (0.90≤a≤1.8 and 0≤b≤0.5); LiaEl-bMbO2-cDc (0.90≤a≤1.8, 0≤b≤0.5, and 0≤c≤0.05); LiE2-bMbO4-cDc (0≤b≤0.5 and 0≤c≤0.05); LiaNi1-b-cCobMcDα(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05, and 0&lt;α≤2); LiaNi1-b-cCobMcO2-αXα(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05, and 0&lt;α&lt;2); LiaNi1-b-cC 0   b  McO2-αX2 (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05, and 0&lt;α&lt;2); LiaNi1-b-cMnbMcDα (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05, and 0&lt;α≤2); LiaNi1-b-cMnbMcO2-αXα (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05, and 0&lt;α&lt;2); LiaNi1-b-cMnbMcO2-αX2 (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05, and 0&lt;α&lt;2); LiaNibEcGdO2 (0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, and 0.001≤d≤0.1); LiaNibCocMndGeO2 (0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, and 0.001≤e≤0.1); LiaNiGbO2 (0.90≤a≤1.8 and 0.001≤b≤0.1); LiaCoGbO2 (0.90≤a≤1.8 and 0.001≤b≤0.1); LiaMnGbO2 (0.90≤a≤1.8 and 0.001≤b≤0.1); LiaMn2GbO4 (0.90≤a≤1.8 and 0.001≤b≤0.1); QO2; QS2; LiQS2; V2O5; LiV2O2; LiRO2; LiNiVO4; Li(3−f)J2(PO4)3 (0≤f≤2); Li(3−f)Fe2(PO4)3 (0≤f≤2); and LiFePO4. In the chemical formulae, A represents Ni, Co, or Mn, M represents Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, or a rare-earth element, D represents O, F, S, or P, E represents Co or Mn; X represents F, S, or P, G represents Al, Cr, Mn, Fe, Mg, La, Ce, Sr, or V, Q represents Ti, Mo, or Mn; R represents Cr, V, Fe, Sc, or Y, and J represents V, Cr, Mn, Co, Ni, or Cu. 
     The cathode active material may also be LiCoO2, LiMnxO2x (x=1 or 2), LiNi1-xMnxO2x (0&lt;x&lt;1), LiNi1-x-yCoxMnyO2 (0≤x≤0.5 and 0≤y≤0.5), LiFePO4, TiS2, FeS2, TiS3, or FeS3, but is not limited thereto. 
     The cathode  321  of the solid-state battery  300  according to this disclosure may selectively include a conductive material, a binder, and a cathode current collector. The conductive material is not particularly limited as long as it has conductivity without causing a chemical change in the solid-state battery  300 . For example, a conductive material including graphite such as natural graphite or artificial graphite, a carbon-based material such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, or thermal black, a conductive fiber such as a carbon fiber or a metallic fiber, carbon fluoride, metallic powder such as aluminum powder or nickel powder, a conductive whisker such as zinc oxide or potassium titanate, a conductive metal oxide such as titanium oxide, and a polyphenylene derivative, and the like may be used. 
     The content of the conductive material may be 1 to 10 parts by weight, for example, 2 to 5 parts by weight based on 100 parts by weight of the cathode active material. In a case in which the content of the conductive material is within the aforementioned range, a finally obtained electrode may have an excellent conductivity characteristic. 
     The binder may be used to improve a coupling force of the active material, the conductive material, and the like. The binder may include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, an ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluorinated rubber, and various copolymers, but is not limited thereto. The content of the binder may be 1 to 50 parts by weight, for example, 2 to 5 parts by weight based on 100 parts by weight of the cathode active material. In a case in which the content of the binder is within the aforementioned range, the active material layer may have a higher coupling force. 
     A porous material having a net structure or mesh structure may be used as the cathode current collector. For example, a porous metal plate formed of stainless steel, nickel, or aluminum may be used as the cathode current collector. However, the cathode current collector is not limited to the foregoing examples. Further, the cathode current collector may be coated with an oxidation-resistant metal or alloy coating film to prevent oxidation. 
     The cathode  321  applied to the solid-state battery  300  may be prepared in a manner in which a composition containing the cathode active material is directly applied onto the cathode current collector containing a metal such as copper and then dried. Alternatively, the cathode  321  may be prepared in a manner in which a cathode active material composition is cast on a separate support and hardened, and in this case, a separate cathode current collector does not have to be provided. 
     The anode  322  included in the solid-state battery  300  may contain a generally used anode active material. A carbon-based material, silicon, silicon oxide, a silicon-based alloy, a silicon-carbon-based material complex, tin, a tin-based alloy, a tin-carbon complex, a metal oxide, or a combination thereof may be used as the anode active material. The anode active material may include a lithium metal and/or a lithium metal alloy. 
     The lithium metal alloy may include lithium and a metal or metalloid that may be alloyed with lithium. For example, the metal or metalloid that may be alloyed with lithium may be Si, Sn, Al, Ge, Pb, Bi, Sb, a Si—Y alloy (Y is an alkali metal, an alkali earth metal, an element of Groups 13 to 16, a transition metal, a rare earth element, or a combination thereof except for Si), a Sn—Y alloy (Y is an alkali metal, an alkali earth metal, an element of Groups 13 to 16, a transition metal, a transition metal oxide such as lithium titanium oxide (Li4Ti5O12), a rare earth element, or a combination thereof except for Sn), and MnOx (0&lt;x≤2). Y may be Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, TI, Ge, P, As, Sb, Bi, S, Se, Te, Po, or a combination thereof. 
     Further, an oxide of the metal or metalloid that may be alloyed with lithium may be lithium titanium oxide, vanadium oxide, lithium vanadium oxide, SnO 2 , SiOx (0&lt;x&lt;2), or the like. For example, the anode active material may contain one or more elements selected from the elements of Groups 13 to 16 of a periodic table of the elements. For example, the anode active material may contain one or more elements selected from Si, Ge, and Sn. 
     The carbon-based material may be crystalline carbon, amorphous carbon, or a mixture thereof. The crystalline carbon may be graphite such as natural graphite or artificial graphite that are in an amorphous, plate, flake, spherical, or fibrous form. The amorphous carbon may be soft carbon (carbon sintered at a low temperature), hard carbon, a mesophase pitch carbide, sintered corks, graphene, carbon black, fullerene soot, a carbon nanotube, a carbon fiber, or the like, but is not limited thereto. 
     Silicon may be selected from Si, SiOx (0&lt;x&lt;2, for example, 0.5 to 1.5), Sn, SnO 2 , a silicon-containing metal alloy, and a mixture thereof. For example, the silicone-containing metal alloy may contain silicon and at least one of Al, Sn, Ag, Fe, Bi, Mg, Zn, In, Ge, Pb, or Ti. 
     The anode may be prepared by almost the same process as the cathode preparing process described above except that the anode active material is used instead of the cathode active material. 
     According to an embodiment, the solid electrolyte layer may be any one or any combination of any two or more of a garnet-type solid electrolyte layer, a NASICON-type solid electrolyte layer, a LISICON-type solid electrolyte layer, a perovskite-type solid electrolyte layer, and a LiPON-type solid electrolyte layer. 
     The garnet-type solid electrolyte layer may be a layer containing lithium lanthanum zirconium oxide (LLZO) represented by Li a La b Zr c O 12  such as Li 7 La 3 Zr 2 O 12 , and the NASICON-type solid electrolyte layer may be a layer containing lithium aluminum titanium phosphate (LATP) represented by Li 1+x Al x Ti 2−x (PO 4 ) 3  (0&lt;x&lt;1) in which Ti has been introduced into a Li 1+x Al x M 2−x (PO 4 ) 3 (LAMP) type compound (where 0&lt;x&lt;2, and M=Zr, Ti, or Ge), lithium aluminum germanium phosphate (LAGP) represented by Li 1+x Al x Ge 2−x (PO 4 ) 3  (0&lt;x&lt;1) such as Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3  into which an excessive amount of lithium has been introduced, and/or lithium zirconium phosphate (LZP) represented by LiZr 2 (PO 4 ) 3 . 
     In addition, the LISICON-type solid electrolyte layer may be a layer containing a solid solution oxide including Li 4 Zn(GeO 4 ) 4 , Li 10 GeP 2 O 12 (LGPO), Li 3.5 Si 0.5 P 0.5 O 4 , Li 10.42 Si(Ge) 1.5 P 1.5 Cl 0.08 O 11.92 , or the like, represented by xLi 3 AO 4 -(1−x)Li 4 BO 4  (A=P, As, V, or the like, and B═Si, Ge, Ti, or the like), and a solid solution sulfide including Li 2 S—P 2 S 5 , Li 2 S—SiS 2 , Li 2 S—SiS 2 —P 2 S 5 , Li 2 S—GeS 2 , or the like, represented by Li 4−x M 1−y M′ y ′S 4  (M=Si or Ge, and M′=P, Al, Zn, or Ga). 
     In an example, ionic conductivity of the solid electrolyte applied to the solid-state battery  300  may be 10 −3  S/cm or more. The ion conductivity may be a value measured at a temperature of 25° C. The ion conductivity may be 1×10 −3  S/cm or more, 2×10 −3  S/cm or more, 3×10 −3  S/cm or more, 4×10 −3  S/cm or more, or 5×10 −3  S/cm or more, and an upper limit of the ion conductivity is not particularly limited, but may be, for example, 1×100 S/cm. When using a solid electrolyte that satisfies the ion conductivity within the above ranges, the solid-state battery  300  may exhibit a relatively high output. 
     The solid-state battery  300  may include a cover portion (not illustrated). The cover portion may be disposed on a part of an outer surface of the body  310 . The cover portion may be formed of an insulating material, and may be formed by attaching a film such as a polymer resin or by applying a ceramic material on the body and then sintering the ceramic material. 
     In the solid-state battery  300 , the first external electrode  331  and the second external electrode  332  may be disposed on opposite surfaces of the body in a first direction (X direction). The first external electrode  331  may be connected to the cathode  321 , and the second external electrode  332  may be connected to the anode  322 . 
     The first external electrode  331  and the second external electrode  332  may contain a conductive metal and glass. The conductive metal may be, for example, one or more conductive metals of copper (Cu), nickel (Ni), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), lead (Pb), and alloys thereof, but is not limited thereto. In addition, the glass contained in the first external electrode  331  and the second external electrode  332  may have a composition in which oxides are mixed. The glass may be, for example, any one or any combination of any two or more of silicon oxide, boron oxide, aluminum oxide, transition metal oxide, alkali metal oxide, and alkaline earth metal oxide, but is not limited thereto. The transition metal may be any one of zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), and nickel (Ni), the alkali metal may be any one of lithium (Li), sodium (Na), and potassium (K), and the alkaline earth metal may be any one or any combination of any two or more of magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba). 
     A method of forming the first external electrode  331  and the second external electrode  332  is not particularly limited. For example, the body  310  may be dipped into a conductive paste containing the conductive metal and the glass, or the conductive paste may be printed on a surface of the body  310  by a screen-printing method or a gravure printing method to form the external electrodes. In addition, various methods such as applying the conductive paste on the surface of the body  310  or transferring a dry film formed by drying the conductive paste onto the body may be used, but the method of forming the first external electrode  331  and the second external electrode  332  is not limited thereto. 
     According to another embodiment, the solid-state battery  300  may include two or more cathodes  321  and two or more anodes  322 , and a plurality of cathodes  321 , a solid electrolyte layer, and a plurality of anodes  322  may be sequentially stacked. Referring to  FIG. 6 , the plurality of cathodes  321  and the plurality of anodes  322  may be arranged to face each other while having the solid electrolyte layer  311  interposed therebetween. The cathode  321  may be exposed from a first surface S 1  of the body  310 , and a portion of the cathode  321  exposed from the first surface S 1  of the body  310  may be connected to the first external electrode  331 . The anode  322  may be exposed from a second surface S 2  of the body  310 , and a portion of the anode  322  exposed from the second surface S 2  of the body  310  may be connected to the second external electrode  332 . As described above, in a case in which the plurality of cathodes  321  and the plurality of anodes  322  facing each other are included, the solid-state battery  300  may implement a high capacity, a high energy density, and/or a high current. 
       FIG. 7  is a block diagram illustrating power management using the solid-state battery  191 , according to an embodiment. 
     According to an embodiment, the wearable device  1  may include a power management unit (PMU)  186  (which may also be referred to as a power manager  186 ) and the battery cells  192 . 
     The power management unit  186  may perform management so that the battery  190  is charged or discharged with power necessary for operation of the wearable device  1 , and may transform power to be suitable for supply to the battery  190  when power is supplied. Here, the power management unit  186  may be implemented by a power management integrated circuit (PMIC), and may include the processor  181  controlling operations for power management, a resistor for current control, and the like. However, in this disclosure, detailed components of the power management unit  186  are not distinguished and collectively referred to as the “power management unit  186 ” for convenience of explanation. In this disclosure, a case in which the power management unit  186  performs a power control operation is described. However, this is for convenience of explanation, and the power control operation may be performed by a processor separate from the power management unit  186 . 
     The wearable device  1  may include the plurality of solid-state batteries  191 , and at least one solid-state battery  191  may be configured to supply power only to a specific electronic component. For example, some of the solid-state batteries  191  may supply power to the processor  181  and the others may supply power to a camera module. 
     As one or more solid-state batteries independently supplying power to each of the electronic components are provided, the wearable device  1  may stably supply power to each of the electronic components. Generally, in a case in which the wearable device  1  uses one battery, an operation of a specific electronic component may cause a change in voltage supplied to another electronic component, which is problematic. This is because a circuit connected to the battery is changed depending on activated electronic components, which changes an impedance of the entire circuit. Therefore, a separate circuit is required to solve such a problem. However, according to an embodiment in this disclosure, a specific solid-state battery  191  independently supplies power to a specific electronic component, and thus, power may be stably supplied to the corresponding electronic component regardless of power supply to another electronic component. 
     A single battery employed in the electronic device according to the related art provides a single output (for example, a single output voltage). Therefore, a power rectifying element or circuit (low dropout (LDO), boosting circuit, or the like) needs to be provided between the battery and the electronic components to appropriately provide power to each electronic component when supplying power to various electronic components. On the other hand, according to embodiments disclosed herein, the battery cells  192  each including at least one solid-state battery  191  may be independently allocated to the electronic components, and thus, an element for dropping a voltage need not be provided between the battery and the electronic components. For example, in a case of a general lithium ion battery, a low-voltage rectifying circuit needs to be additionally provided to drive an image sensor using power of 2.8 V, 1.8 V, or 1.2 V. On the other hand, the solid-state batteries  191  may be combined in series and/or in parallel according to an output value, and supply a voltage of 2.8 V, 1.8 V, or 1.2 V to the image sensor without the rectifying circuit. 
     Referring to  FIG. 7 , according to an embodiment, the wearable device  1  may include the battery cells  192  allocated to the electronic components (for example, the processor  181 , the display device  170 , the audio module  187 , a memory  182 , and the cameras  150  and  160 ), respectively. For example, the battery cells  192  may include a first battery cell  192 - 1 , a second battery cell  192 - 2 , a third battery cell  192 - 3 , a fourth battery cell  192 - 4 , a fifth battery cell  192 - 5 , and a sixth battery cell  192 - 6  allocated to the processor  181 , the communication module  185 , the display device  170 , the audio module  187 , the memory  182 , and the first and second cameras  150  and  160 , respectively. 
     Each of the battery cells  192  may include at least one solid-state battery  191 . Each of the battery cells  192  may include a plurality of solid-state batteries  191  connected in series or in parallel. Each of the battery cells  192  may provide an output suitable for an electronic component to which the corresponding battery cell  192  is allocated. For example, in a case in which the processor  181  requires a first voltage, the solid-state batteries  191  included in the first battery cell  192 - 1  may be combined so that the first battery cell  192 - 1  outputs the first voltage. In a case in which the first and second cameras  150  and  160  require a second voltage, the solid-state batteries  191  included in the sixth battery cell  192 - 6  may be combined differently from the solid-state batteries  191  included in the first battery cell  192 - 1  to provide the second voltage. 
     According to an embodiment, the wearable device  1  may further include an additional battery. For example, the wearable device  1  may include the lithium ion battery  193 . The lithium ion battery  193  may be used to assist or substitute for the solid-state batteries  191  or the battery cells  192 . For example, in a case in which the state of charge of the first battery cell  192 - 1  is low, the lithium ion battery  193  may supply power to the processor  181  together with the first battery cell  192 - 1 . As another example, in a case in which the first battery cell  192 - 1  is almost empty, the lithium ion battery  193  may supply power to the processor  181  instead of the first battery cell  192 - 1 . 
     According to an embodiment, the wearable device  1  may include a charging device  194 . The lithium ion battery  193  or the solid-state battery  191  may be charged by the charging device  194 . The charging device  194  may include, for example, a USB port. According to an embodiment, the solid-state battery  191  may be charged by the power management unit  186 , rather than being directly charged by the charging device  194 . For example, the power management unit  186  may discharge the liquid ion battery  193  to charge the solid-state battery  191 . According to an embodiment, the wearable device  1  may further include an auxiliary charging battery  195 . The auxiliary charging battery  195  may be charged by the charging device  194 . 
       FIG. 8  is a flowchart illustrating a discharge of the solid-state battery  191  corresponding to a used device, according to an embodiment. 
     According to an embodiment, the power management unit  186  may be configured to selectively supply power to the electronic components based on the activation of the electronic components. For example, referring to  FIG. 7 , the power management unit  186  may be configured to selectively discharge a battery cell that is allocated to an activated one of the electronic components among the plurality of battery cells  192 . Referring to  FIG. 8 , the power management unit  186  may supply power to a specific electronic component based on activation of a function related to the corresponding electronic component. In the wearable device  1 , the power management unit  186  may check a connected device in operation  211 , and in a case in which it is determined that the device is used in operation  213 , the wearable device  1  may supply power to the corresponding device by discharging the solid-state battery  191  allocated to the corresponding device in operation  215 . 
       FIG. 9  is a flowchart illustrating a charge of the solid-state battery  191  based on the state of charge, according to an embodiment. 
     According to an embodiment, the battery cells  192  may be individually charged or discharged. The power management unit  186  may collectively charge all the battery cells  192  or selectively charge some of the battery cells  192 . 
     Referring to  FIG. 9 , the power management unit  186  checks the state of charge of each battery cell  192  in operation  221 , and in a case in which an empty battery cell is found in operation  223 , the solid-state batteries  191  in the specific battery cell whose state of charge is low may be charged in operation  225 . According to another embodiment, the power management unit  186  may charge a specific battery cell in a case in which the state of charge of the corresponding battery cell is lower than a designated value. 
     According to an embodiment, the power management unit  186  may preferentially charge the battery cell  192  whose state of charge is low. For example, in a case in which, at a specific point in time, the state of charge of the battery cell  192  that is allocated to the processor  181  is 30%, and the state of charge of the battery cell  192  that is allocated to the first and second cameras  150  and  160  is 80%, the power management unit  186  may preferentially charge the battery cell  192  that is allocated to the processor  181 . The battery cell  192  may be charged at a relatively high speed by preferentially charging the battery cell  192  that needs to be charged. 
       FIG. 10  is a flowchart illustrating selective use of a main battery based on an operation state of the processor  181  according to an embodiment. 
     According to an embodiment, the wearable device  1  may further include the main battery (for example, the lithium ion battery  193  of  FIG. 2 ) in addition to the solid-state battery  191 . The main battery may have a higher capacity than that of the battery cell  192 . For example, the main battery may include the lithium ion battery  193 . As another example, the main battery may include a battery cell including a relatively large number of solid-state batteries  191 . 
     The power management unit  186  may operate the wearable device  1  by simultaneously or individually discharging the main battery and the battery cell  192 . Referring to  FIG. 10 , in operation  231  and operation  233 , the power management unit  186  may determine whether the processor  181  is in a low power mode (for example, a sleep mode or a standby mode) or in a normal operation mode, and may determine a battery for supplying power to the electronic components based on the determination result. For example, in a case in which the processor  181  is in the standby mode or the sleep mode, the power management unit  186  may supply power to each electronic component in operation  235 , by only using the solid-state battery  191 . As another example, in a case in which the processor  181  is in the normal operation mode, the power management unit  186  may supply power to each electronic component in operation  237 , by using the main battery. As another example, in a case in which the processor  181  is in the normal operation mode, the power management unit  186  may supply power to each electronic component in operation  237 , by using both the main battery and the solid-state battery  191 . 
       FIG. 11  illustrates a circuit supplying power to the processor  181 , according to an embodiment. 
     Referring to  FIG. 11 , according to an embodiment, the processor  181  may include a main processor  181   a  and an auxiliary processor  181   b . The auxiliary processor  181   b  consumes less power than the main processor  181   a , and in a case in which the wearable device  1  is in the standby mode or the sleep mode, the main processor  181   a  may be inactivated and only the auxiliary processor  181   b  may be activated. According to an embodiment, the power management unit  186  may be configured to determine whether to discharge the lithium ion battery  193  based on whether the main processor  181   a  is activated. In a case in which the wearable device  1  is in the standby mode or the sleep mode, the power management unit  186  may supply power to the auxiliary processor  181   b  by discharging the battery cell  192 . In a case in which the wearable device  1  is in the normal operation mode, both the lithium ion battery  193  and the solid-state battery  191  may supply power to the main processor  181   a  and the auxiliary processor  181   b . According to an embodiment, the use of the lithium ion battery  193  and the solid-state battery  191  may be switched depending on the operation mode of the processor  181 , thereby increasing lifetime and efficiency of the main battery. 
       FIG. 12  is a flowchart illustrating a power supply method in which the main battery (for example, the lithium ion battery  193  of  FIG. 7 ) is used to assist the solid-state battery  191 , according to an embodiment. 
     According to an embodiment, the power management unit  186  may be configured to determine whether to discharge the lithium ion battery  193  based on whether the processor (for example, the processor  181  of  FIG. 7 ) is activated. Referring to  FIG. 12 , according to an embodiment, the power management unit  186  may check a power consumption amount of the solid-state battery  191  that supplies power to a specific electronic component, in operation  241 , and may determine whether to additionally use the main battery to supply power to the corresponding electronic component based on the checked power consumption amount, in operation  243 . For example, in a case in which less load is applied to the processor  181 , and the power consumption amount of the solid-state battery  191  that is allocated to the processor  181  is thus not large, only the solid-state battery  191  that is allocated to the processor  181  may supply power to the processor  181  in operation  247 . As another example, in a case in which the wearable device  1  executes multiple functions, and a high load is applied to the processor  181 , the main battery may supply power to the processor  181  together with the solid-state battery  191  in operation  245 . 
     According to another embodiment, the power management unit  186  may check a power consumption amount of a specific solid-state battery  191 , and may determine whether or not to additionally use the main battery to charge the corresponding solid-state battery  191  based on the checked power consumption amount. For example, in a case in which a high load is applied to the processor  181 , the main battery may supply power to (that is, charge) the solid-state battery  191  while the solid-state battery  191  supplies power to the processor  181 . 
     According to an embodiment, the power management unit  186  may measure a discharge speed by monitoring the state of charge of each of multiple battery cells  192 , and determine whether or not the discharge speed exceeds a threshold value corresponding to the battery cell  192 . According to an embodiment, in a case in which it is determined that the discharge speed of the solid-state battery  191  exceeds a reference value, the power management unit  186  may charge the corresponding solid-state battery  191  by discharging the main battery or may control the main battery to supply power to a specific electronic component together with the solid-state battery  191 . 
     According to an embodiment, the power management unit  186  may control the battery cells  192  to supply or receive power to or from each other. For example, referring to  FIG. 7 , the first battery cell  192 - 1  that is allocated to the processor  181  and the sixth battery cell  192 - 6  that is allocated to the first and second cameras  150  and  160  may supply or receive power to or from each other. For example, in a case in which the state of charge of the first battery cell  192 - 1  is low, the power management unit  186  may control the corresponding battery cell  192 - 1  to receive power from the sixth battery cell  192 - 6  whose state of charge is high. As another example, in a case in which the state of charge of the first battery cell  192 - 1  is high, the power management unit  186  may control the corresponding battery cell  192 - 1  to charge the sixth battery cell  192 - 6  whose state of charge is low. 
     Hereinafter, the first and second cameras  150  and  160  disposed in the wearable device  1  will be described with reference to  FIGS. 13 through 22 . In a case in which a camera is disposed in the wearable device  1 , a thickness of the rim  110  or a thickness of a portion connecting the rim  110  and the temple  140  of the wearable device  1  may be increased by the size of the camera, which may impair the appearance of the wearable device  1 . 
     Particularly, since the image sensor that may obtain a high-resolution image has a relatively large size, in a case in which a camera is disposed so that the imaging surface of the sensor is oriented toward the side in front of the glasses, the appearance of the wearable device  1  is further impaired, the productivity of the wearable device  1  deteriorates, such that the wearer does not constantly use the wearable device  1  in daily life. 
       FIG. 13  illustrates the first and second cameras  150  and  160  mounted on the wearable device  1  (e.g., glasses) according to an embodiment.  FIG. 13  schematically illustrates the first and second cameras  150  and  160  and the electronic components provided on the left side (or one side) of the wearable device  1 , and the same or similar components may be provided on the right side (or the other side) of the wearable device. 
     Referring to  FIG. 13 , the wearable device  1  may include the first camera  150  disposed at the upper portion of the rim  110 . The first camera  150  may be configured to capture an image of the subject positioned in front of the wearable device  1 . That is, the first camera  150  may be configured to capture an image of the subject positioned in a direction in which the face of the wearer is oriented. 
     According to an embodiment, the first camera  150  may include the reflection member  153 , at least one first lens  151 , and the image sensor  152 . The image sensor  152  may be electrically connected to the board  141 , and a connector  142  may electrically connect the image sensor  152  and the board  141  to each other. The image sensor  152  may receive power through the connector  142 , and may transmit an image signal to another electronic component (for example, an image processor) mounted on the board  141 . 
     According to an embodiment, the reflection member  153  of the first camera  150  may change a direction of light incident from the side in front of the wearable device  1 , toward the imaging surface  152   a  of the image sensor  152 . For example, the reflection member  153  may reflect light incident from the side in front of the wearable device  1  in the +X direction toward the image sensor  152  in the +Y direction. Accordingly, the image sensor  152  may be disposed so that the imaging surface  152   a  is oriented toward the lateral side of the wearable device  1  (that is, in the Y direction). 
     According to an embodiment, the wearable device  1  may include the second camera  160  disposed at the lower portion of the rim  110 . The second camera  160  may be configured to capture an image of the eye of the wearer. The gaze of the wearer is changed depending on the direction of the eye, and the wearable device  1  may determine which direction or which point to which the gaze of the wearer is directed by using the second camera  160 . 
     According to an embodiment, the second camera  160  may include the reflection member  163  and the image sensor  162 . At least one second lens may be disposed between the reflection member  163  and the image sensor  162 . The image sensor  162  may be electrically connected to the board  141 , and a connector may electrically connect the image sensor  162  and the board  141  to each other. Although not illustrated, the connector may be accommodated in the rim  110  of the wearable device  1 , and may electrically connect the second camera  160  and the board  141  (or the electronic component mounted on the board  141 ) to each other. 
     According to an embodiment, the reflection member  163  of the second camera  160  may change a direction of light incident from behind the wearable device  1 , toward the image sensor  162 . For example, the reflection member  153  may reflect light incident from the side in front of the wearable device  1  in the −X direction toward the image sensor  152  in the −Z direction. Accordingly, the image sensor  152  may be disposed to be oriented toward the upper side of the wearable device  1  (that is, in the +Z direction). 
     According to an embodiment, the reflection member  153  or  163  may be partially opaque. For example, a surface (for example, a triangular side surface of the reflection member  153  or  163  in the illustrated embodiment) other than an incident surface, an emission surface, and a reflection surface of the reflection member  153  or  163  does not have to transmit light. For example, a side surface of the prism may be covered with an opaque material. 
       FIG. 14  illustrates a hinge connecting the rim  110  and the temple  140  of the wearable device  1 , according to an embodiment. 
     According to an embodiment, the temple  140  may extend from the rim  110  and may be hung on the ear of the user. The temple  140  may be foldably coupled to the rim  110 . Referring to  FIG. 14 , the temple  140  of the wearable device  1  may be foldably coupled to the rim  110  (or a portion  111  extending from one side of the rim  110 ). The temple  140  may be foldably mounted, thereby facilitating storage or carrying. For example, the temple  140  may be connected to the rim  110  through a hinge  143 . 
     According to an embodiment, as the temple  140  is folded and unfolded, an electrical path connecting the image sensor  152  and the board  141  may also be folded or unfolded. According to an embodiment, the connector  142  connecting the image sensor  152  and the board  141  to each other may be implemented by a flexible board  142  to prevent damage caused by folding or unfolding of the temple  140 . The flexible board  142  may be naturally folded by rotation of the temple  140 , such that the electrical connection between the image sensor  152  and the board  141  may be maintained. 
       FIG. 15A  illustrates a portion of the glass lens  130  that functions as the reflection member, according to an embodiment.  FIG. 15B  illustrates a portion of the glass lens  130 , that functions as the reflection member, according to an embodiment.  FIG. 16A  is a cross-sectional view taken along line II-II′ of  FIG. 15A .  FIG. 16B  is a cross-sectional view taken along line III-III′ of  FIG. 15B . 
     The reflection member  153  or  163  illustrated in  FIGS. 1, 13, 14 , and the like may be provided as a part of the glass lens  130 . The glass lens  130  may have a reflection surface  131  configured to fold a path of light incident toward the glass lens  130  toward the image sensor  152 . A separate coating layer may be applied on the reflection surface  131  to induce total reflection of light. Referring to  FIGS. 15A and 16A , the glass lens  130  may include the reflection surface  131 . The reflection surface  131  may be formed by machining a part of the glass lens  130 . A direction of light incident on the reflection surface  131  from the side in front of the wearable device  1  may be changed toward the image sensor  152 . That is, a direction of light incident from the side in front of the wearable device  1  may be changed toward the image sensor  152  without a separate reflection member (for example, the reflection member  153  or  163  of  FIG. 13 ). According to an embodiment, the reflection surface  131  of the glass lens  130  may have a curved surface or a flat surface. For example, the glass lens  130  may have the reflection surface  131  obliquely facing the imaging surface  152   a  of the image sensor  152 . 
     Referring to  FIGS. 15B and 16B , a back surface of the glass lens  130  may be partially machined to provide the reflection surface  131 . The glass lens  130  of  FIG. 15A  has a recess  132  disposed in a front surface thereof, whereas the glass lens  130  of  FIG. 15B  has the recess  132  disposed in a back surface thereof. 
     In the illustrated embodiment, the glass lens  130  is partially machined to form the reflection surface  131 . According to another embodiment, the reflection surface  131  may be provided by the reflection member  153  or  163  separate from the glass lens  130 , and the reflection member  153  or  163  may be seated on the glass lens  130 . For example, the glass lens  130  may have a recess  132  machined to correspond to the prism, and the prism may be seated in the recess  132  provided in the glass lens  130 . 
       FIG. 17  illustrates a state in which the first camera  150  is disposed at the upper portion of the rim  110 , according to an embodiment. 
     According to an embodiment, the first camera  150  of the wearable device  1  may be embedded in the rim  110 . For example, the first camera  150  may be embedded in a portion of the rim  110  that surrounds an upper portion of the glass lens  130 . For example, at least some of the reflection member  153 , at least one lens  151 , or the image sensor  152  may be embedded in a portion of the rim  110  that surrounds the upper portion of the glass lens  130  and extends in the Y direction. Referring to  FIG. 17 , the camera  150  may include the image sensor  152  whose imaging surface  152   a  is oriented toward the lateral side of the wearable device  1 . According to an embodiment, the imaging surface  152   a  of the image sensor  152  may have an aspect ratio other than 1, and in this case, the image sensor  152  may be disposed so that a short side  152   c  corresponds to a height of the image sensor  152  when the wearable device  1  is viewed from the side in front of the wearable device  1 . For example, the image sensor  152  may be disposed so that a long side  152   b  of the imaging surface  152   a  extends in the X direction and the short side  152   c  extends in the Z direction. 
     In a case in which the image sensor  152  is disposed so that the short side  152   c  corresponds to the height, the thickness of the first camera  150  may be decreased when viewed from the side in front of the wearable device  1 , which improves the appearance of the first camera  150 . As the thickness of the first camera  150  is decreased, the camera  150  may be accommodated in a portion of the rim  110 . Referring to  FIG. 17 , the camera  150  is accommodated in the upper portion of the rim  110 . The upper portion of the rim  110  may have a space for accommodating the first camera  150 , and the first camera  150  may be fitted into the space. 
     In a case in which the first camera  150  is accommodated in the upper portion of the rim  110 , at least the reflection member  153  of the first camera  150  may be exposed to the outside of the rim  110 . For example, the rim  110  may have an opening that is opened toward the side in front of the wearable device  1  at a position corresponding to the reflection member  153 , and light may enter the first camera  150  through the opening. According to an embodiment, a transparent cover may be disposed on the opening to prevent dust from being introduced or improve the appearance. 
     In the illustrated embodiment, the first camera  150  may be disposed in the rim  110  behind the glass lens  130 . In this case, a part of the first camera  150  may be visually recognized from the side in front of the wearable device  1  through the glass lens  130 . 
       FIG. 18  illustrates a state in which the first camera  150  is disposed at the bridge  120  of the wearable device  1 , according to an embodiment.  FIG. 19  illustrates a state in which two first cameras  150  are disposed at the bridge  120  of the wearable device  1 . 
     Referring to  FIG. 18 , the frame  105  of the wearable device  1  may include the bridge  120  connecting a pair of rims  110 , and the first camera  150  may be at least partially disposed at the bridge  120 . According to an embodiment, at least some of the reflection member  153 , the lens  151 , or the image sensor  152  may be embedded in the bridge  120 . For example, the reflection member  153  of the camera  150  may be disposed in an inner region surrounded by the rim  110  behind the left glass lens  130 , and the image sensor  152  or the lens  151  may be disposed behind the bridge  120 . The image sensor  152  may be disposed toward the side in the −Y direction (or the +Y direction), and the reflection member  153  may change a direction of light incident from the side in front of the wearable device  1  toward the image sensor  152 . According to an embodiment, as the image sensor  152  is disposed at the bridge  120 , an electrical wiring connecting the image sensor  152  to the board  141  in the temple  140  may be disposed in the rim  110 . According to an embodiment, the first reflection member  153  may be at least partially disposed in a region surrounded by the rim  110 . For example, the reflection surface of the first reflection member  153  may be positioned in the region surrounded by the rim  110 . 
     Referring to  FIG. 19 , according to an embodiment, two first cameras, a left camera  150 L and a right camera  150 R, may be disposed at the bridge  120 . A left image sensor  152 L of the left camera  150 L and a right image sensor  152 R of the right camera  150 R may be oriented in different directions. That is, imaging surfaces of the left and right image sensors  152 L and  152 R are oriented in different directions. For example, the imaging surface of the left image sensor  152 L may be oriented toward the left side, and the imaging surface of the right image sensor  152 R may be oriented toward the right side. 
     According to an embodiment, the left and right cameras  150 L and  150 R may share the board  141  on which the left and right image sensors  152 L and  152 R are mounted. For example, the left and right image sensors  152 L and  152 R may be disposed on one surface and the other surface of the board  141 , respectively. 
     Further, in a case in which the left and right image sensors  152 L and  152 R are disposed on opposite surfaces of one board  141 , the board  141  may be moved in a direction orthogonal to the optical axis, such that image stabilization of both of the cameras  150 L and  150 R may be implemented at once. 
     According to an embodiment, left and right reflection members  153 L and  153 R may be at least partially disposed in a region surrounded by the rim  110 . According to an embodiment, the left and right reflection members  153 L and  153 R that initially receive light in the left and right cameras  150 L and  150 R, respectively, may be spaced apart from each other. Therefore, the wearable device  1  may obtain information regarding a distance between the wearable device  1  and a subject positioned in front of the wearable device  1  by using the left and right cameras  150 L and  150 R. In the illustrated embodiment, the left and right cameras  150 L and  150 R may be partially visually recognized from the side in front of the wearable device  1  through the glass lens  130 . However, according to another embodiment, the left and right cameras  150 L and  150 R may be partially accommodated in the rim  110 . 
     Alternatively, a housing forming an external portion of the left and right cameras  150 L and  150 R may connect the rims  110  to each other to function as the bridge  120 . 
     In the first camera  150  and the left and right cameras  150 L and  150 R illustrated in  FIGS. 18 and 19 , the reflection members  153 ,  153 L, and  153 R may be replaced with a machined surface of the glass lens  130 , as illustrated in  FIGS. 16A and 16B . For example, in  FIG. 18 , the reflection members  153 ,  153 L, and  153 R may be replaced with the reflection surface (for example, the reflection surface  131  of  FIGS. 16A and 16B ) as a part of the glass lens  130 . 
       FIGS. 20A through 20D  illustrate various forms of a light guide prism, according to an embodiment.  FIG. 21  illustrates a lens  156  additionally disposed on the reflection member  153  of the first camera  150 , according to an embodiment. 
       FIGS. 20A through 20D  illustrate light guide prisms  154   a ,  154   b ,  154   c , and  154   d  through which light passing through the reflection member  153  additionally passes before reaching the image sensor  152 . 
     According to an embodiment, the light guide prism  154   a ,  154   b ,  154   c , or  154   d  may be configured to reflect light incident to the light guide prism  154   a ,  154   b ,  154   c , or  154   d  at least twice inside the light guide prism  154   a ,  154   b ,  154   c , or  154   d . According to an embodiment, the light guide prism  154   a ,  154   b ,  154   c , or  154   d  may have two or more reflection surfaces. Light reflected from the reflection member  153  may be sequentially reflected from the reflection surfaces in the light guide prism  154   a ,  154   b ,  154   c , or  154   d  and then reach the image sensor  152 . According to an embodiment, the light guide prism  154   a ,  154   b ,  154   c , or  154   d  may lengthen a path of the light. Therefore, the degree of freedom in designing disposition of the image sensor  152  may be further increased. For example, a distance between the reflection member  153  and the image sensor  152  may be freely increased by using the light guide prism  154   a ,  154   b ,  154   c , or  154   d.    
     According to an embodiment, the image sensor  152  may be disposed so as to form various angles with respect to the side in front of the wearable device  1  by using the light guide prism  154   a ,  154   b ,  154   c , or  154   d . For example, in the embodiments of  FIGS. 20A, 20B, and 20D , the image sensor  152  is disposed at an angle of about 45° with respect to the reflection surface of the reflection member  153 , and is oriented toward the lateral side of the wearable device  1 . On the other hand, referring to the embodiment of  FIG. 20C , the image sensor  152  may be disposed so as to be oblique with respect to both the lateral side of the wearable device  1  and the side in front of the wearable device  1 . For example, the image sensor  152  may be oriented at an angle of about 45° (or 135°) with respect to the side in front of the wearable device  1 . 
     Referring to the embodiment of  FIG. 20B , an additional lens  151  may be provided between the light guide prism  154   a ,  154   b ,  154   c , or  154   d  and the reflection member  153 . In the illustrated embodiment, the additional lens  151  is schematically illustrated. Two or more lenses may be disposed between the reflection member  153  and the light guide prism  154   a ,  154   b ,  154   c , or  154   d.    
     Referring to the embodiment of  FIG. 20D , a separate wide-angle lens  155  may be coupled to the reflection member  153 . As the wide-angle lens  155  is provided in front of the reflection member  153 , an angle of view of the camera may be increased. 
     Meanwhile, the embodiments illustrated in  FIGS. 20A through 20D  are only examples, and the form of the light guide prism  154   a ,  154   b ,  154   c , or  154   d  and the forms of the lenses  151  and  155  may vary according to other embodiments. 
     Referring to  FIG. 21 , the separate lens  156  may be coupled to the reflection member  153  according to an embodiment. Since the separate lens  156  is provided in front of the reflection member  153 , the angle of view of the camera may be increased. 
     The light guide prism  154   a ,  154   b ,  154   c , or  154   d  or the lens  155  or  156  described with reference to  FIGS. 20A through 21  may be similarly applied to the second camera  160  of  FIG. 13 . 
       FIG. 22  illustrates a state in which the wearable device  1  displays a subject positioned behind the wearer, according to an embodiment. 
     Referring to  FIG. 22 , the wearable device  1  may include the left and right cameras  150 L and  150 R that may capture an image of an area behind the wearer on the left side and the right side, respectively. The left camera  150 L may include the left reflection member  153 L, at least one left lens  151 L, and the left image sensor  152 L, and the right camera  150 R may include the right reflection member  153 R, at least one right lens  151 R, and the right image sensor  152 R. The left or right image sensor  152 L or  152 R may be disposed so as to be oriented toward the lateral side (that is, the left side or the right side) of the wearable device  1 , and the left or right reflection member  153 L or  153 R may be configured to reflect light incident from behind the wearer toward the left or right image sensor  152 L or  152 R. 
     According to an embodiment, the wearable device  1  may display, to the wearer, images of subjects  400  and  500  positioned behind the wearer, the image being captured by the left and right cameras  150 L and  150 R. For example, the wearable device  1  may include a screen  171  provided in the glass lens  130  and a projector that outputs an image on the screen  171 , and a rear view of the wearer may be displayed on the screen  171 . As another example, a transparent display may be provided in the lens of the wearable device  1  and the rear view may be directly output on the transparent display. 
     According to an embodiment, in a case in which the wearer walks on a street, the wearable device  1  may inform the wearer of an object positioned behind the wearer. Referring to  FIG. 22 , the left camera  150 L captures images of a vehicle  500  and a pedestrian  400  positioned behind the wearer, and an image  400 ″ including an image  500 ″ of the vehicle and an image of a part or whole of the pedestrian may be displayed on the left side screen  171 . According to an embodiment, the right camera  150 R captures images of the vehicle  500  and the pedestrian  400  positioned behind the wearer, and an image  400 ′ including an image  500 ′ of the vehicle and an image of a part or whole of the pedestrian may be displayed on the right side screen  171 . 
     According to an embodiment, the wearable device  1  may inform the wearer of a risk of approach of an object from behind by using the left and right cameras  150 L and  150 R. For example, the wearable device  1  may display a rearview image to inform the user of the risk when the vehicle  500  approaches the wearer from behind the wearer. The wearable device  1  may analyze an image obtained by each of the left and right cameras  150 L and  150 R to check a distance between the vehicle  500  and the wearer in real time, and in a case in which it is determined that the wearer may be in danger due to the vehicle  500 , the wearable device  1  may display a warning alarm to the user based on the determined result. 
       FIG. 23  illustrates gesture recognition using the wearable device  1 , according to an embodiment. 
     According to an embodiment, the wearable device  1  may execute a function of recognizing a gesture of the wearer through the first camera  150  and perform an operation based on the recognized gesture. The wearable device  1  may execute a function of recording a gesture G of the hand of the wearer performing an operation based on the gesture G. For example, when the wearer listens to the music through the wearable device  1 , the wearable device  1  may recognize a gesture in which the hand of the user moves upward or downward through the first camera  15 -, and turn down or up the volume of the music in response to the gesture. 
     According to an embodiment, the wearable device  1  may recognize a still image in addition to a moving object (for example, the hand of the wearer) through the camera. For example, the wearable device  1  may execute a function of recognizing a designated shape and performing an operation based on the recognized shape. For example, the wearable device  1  may recognize the shape of the finger of the wearer by using the first camera  150 , and execute a function corresponding to the recognized shape. As another example, in a case in which the wearer watches a QR code, the wearable device  1  may capture an image of the QR code by using the first camera  150 , and execute a function corresponding to the QR code. 
     According to another embodiment, the wearable device  1  may receive an input signal from another wearable device worn by the wearer. For example, in a case in which the wearer wears a smartwatch, the wearer may use a button or a touch screen of the smartwatch to control the function of the wearable device  1 . 
       FIG. 24  illustrates a state in which users located in different places share fields of view with each other, according to an embodiment. 
     According to an embodiment, the wearers of the wearable devices  1  may share field-of-view information. According to an embodiment, in a case in which a first user A wearing a first wearable device  1  is looking at a pedestrian  400  positioned in front of the first user A, the first wearable device  1  may capture an image of the pedestrian  400  by using the camera and transmit the image to a second wearable device  2  including a glass lens  230 , a first camera  250 , and a screen  271 . 
     For example, the first wearable device  1  may stream the captured image in real time through a communication circuitry. The second wearable device  2  may receive the image streamed by the first wearable device  1  and display a pedestrian image  400 ′ on the screen  271  of the second wearable device  2 . 
     The second wearable device  2  may also capture an image of a vehicle  500  positioned in front of the second wearable device  2  and transmit corresponding image information to the first wearable device  1 . The first wearable device  1  may display a vehicle image  500 ′ received from the second wearable device  2  on the screen  171 . Therefore, the first user A and a second user B may share the fields of view with each other. 
     As another example, in a case in which the first user A is watching a baseball game, and the second user B is watching a soccer game, the first user A may watch the soccer game that the second user B is watching, through the wearable device  1  while watching the baseball game, and the second user B may also watch the baseball game that the first user A is watching, through the wearable device  2  while watching the soccer game. 
       FIG. 25  illustrates a keyboard input using a gaze of the wearer, according to an embodiment. 
     According to an embodiment, the wearer may interact with the wearable device  1  only by using a gaze. According to an embodiment, the wearable device  1  may include the second camera  160  tracking the eye of the wearer, and the camera may measure a direction in which the eye of the wearer is directed. 
     The wearable device  1  may output a virtual keyboard  510  on a glass lens  130   a  (or a screen provided in the glass lens  130   a ) on one side, and the wearable device  1  may recognize a key of the virtual keyboard  510  to which the gaze of the wearer is directed by using the second camera  160 . The wearable device  1  may detect a direction in which the gaze of the wearer is directed, determine a key corresponding to the direction in which the gaze is directed, and execute a function corresponding to the key. For example, the wearable device  1  inputs an “H” key based on a determination that the user is watching the “H” key. In a case in which the “H” key is input, the wearable device  1  may display the input of the “H” key on a glass lens  130   b  on the left side (or a screen provided in the glass lens  130   b  on the left side). 
     According to an embodiment, the wearable device  1  may recognize a blink of the wearer as a kind of instruction. The wearable device  1  may determine whether or not the eye of the wearer blinks, how many times the eye of the wearer blinks, or how fast the eye of the wearer blinks by using the second camera  160 . For example, in a case in which the gaze of the wearer is fixed to a specific key and the eye of the wearer quickly blinks twice, the wearable device  1  may recognize that the specific key is clicked, and in a case in which the eye of the wearer does not blink, the wearable device  1  may recognize that no input is made. 
       FIG. 26  illustrates a driver wearing the wearable device  1  and a field of view of the driver, according to an embodiment. 
     According to an embodiment, the wearable device  1  may assist in driving. For example, the wearable device  1  may display a visual object  710  for guiding a route to a destination and vehicle state information  740  (for example, a remaining fuel amount, a state of charge of the battery, a speed, or an acceleration). 
     According to an embodiment, the wearable device  1  may display the visual guide  710  in addition to a front field of view actually viewed by the driver. For example, the wearable device  1  may superimpose the visual guide  710  on a route that the vehicle needs to follow to reach a destination. As another example, in a case in which a destination is within the field of the view of the driver, a visual object may be superimposed on the destination to help the driver be able to intuitively understand where the destination is located. 
     According to an embodiment, in a case in which the driver wears the wearable device  1 , the wearable device  1  may measure a distance between the vehicle of the driver and a vehicle  600  located in front of the vehicle of the driver. The wearable device  1  may include two cameras (for example, two first cameras  150  provided at both sides of the wearable device  1 ) oriented toward the side in front of the wearable device  1 , and a distance between the wearable device  1  and the preceding vehicle  600  may be measured by using the two camera. According to an embodiment, the wearable device  1  may provide various types of information to the driver based on information regarding a distance between the vehicle of the driver and another vehicle. For example, in a case in which a distance from the preceding vehicle rapidly decreases, the wearable device  1  may display a warning  730  that informs of a collision risk. 
     According to an embodiment, the wearable device  1  may measure a degree of alertness of the driver by using the second camera  160  and may issue a warning to the driver based on the measurement result. According to an embodiment, the wearable device  1  may monitor an interval or pattern of blinking of the eye of the driver through the second camera  160 , and may determine whether or not the driver dozes off while driving based on the monitoring result. The wearable device  1  may issue a warning to the driver by using various means in a case in which it is determined that the driver dozes off while driving. For example, a feedback may be made for the driver by a warning sound output from the audio output device provided in the wearable device  1  or a vibration generated using the haptic module  188  (see  FIG. 2 ). 
     According to an embodiment, in a case in which the driver does not keep his/her eyes forward, the wearable device  1  may issue a warning to make the driver keep his/her eyes forward. For example, the wearable device  1  may issue a warning to the driver based on a proportion of a time for which the driver keeps his/her eyes forward in a designated time interval. 
     According to an embodiment, the wearable device  1  may detect a posture of the face of the wearer. The wearable device  1  may detect movement of the head of the wearer through a head tracking camera (for example, the first camera  150  of  FIG. 1 ). When the wearer moves his/her head, an angle of a subject obtained by the first camera  150  may be changed accordingly, and the wearable device  1  may detect the movement of the head of the wearer by using the obtained angle of the subject. For example, the wearable device  1  may detect a motion that the head of the user is turned left and right, a motion in which the user nods his/her head, and the like. According to another embodiment, the wearable device  1  may detect how the head of the wearer is moved by using a motion sensor such as an acceleration sensor or a gyro sensor. 
     According to an embodiment, the wearable device  1  may detect a motion of the head of the user and execute a function corresponding to the motion. For example, in a situation where the wearable device  1  asks the wearer for agreement on any item, when the user nods his/her head, it may be determined that the user agrees on the item, and when the user turns his/her head left and right, it may be determined that the user does not agree on the item. As another example, the wearable device  1  may operate a display menu according to a motion of the head, or may adjust a display position according to an angle of the head. 
     According to an embodiment, the wearable device  1  may measure a depth of an object positioned in front of the wearable device  1  by using two cameras. Based on the same principle that two eyes of a human are spaced apart from each other and may determine a distance to a subject, the wearable device  1  may obtain information regarding the depth of the subject by using two cameras spaced apart from each other. 
     According to an embodiment, one of two head tracking cameras (for example, the first camera  150  of  FIG. 1 ) may be equipped with an RGB sensor, and the other one of the two head tracking cameras may be equipped with a monochrome sensor. In this case, the wearable device  1  may combine images obtained by two cameras, thereby improving image quality. 
     As set forth above, according to embodiments disclosed herein, various devices may be easily provided in a small space of a wearable device. For example, a battery or a camera provided in a wearable device according to the disclosure herein may contribute to improving the usability or appearance of the wearable device. 
     The input device  183 , the sensor module  184 , communication module  185 , the processor  181 , the main processor  181   a , the auxiliary processor  181   b , the memory  182 , the power management unit  186 , the display device  170 , the audio module  187 , the haptic module  188 , the interface  189 , the charging device  194 , the processors, and the memories in  FIGS. 1 to 26  that perform the operations described in this application are implemented by hardware components configured to perform the operations described in this application that are performed by the hardware components. Examples of hardware components that may be used to perform the operations described in this application where appropriate include controllers, sensors, generators, drivers, memories, comparators, arithmetic logic units, adders, subtractors, multipliers, dividers, integrators, and any other electronic components configured to perform the operations described in this application. In other examples, one or more of the hardware components that perform the operations described in this application are implemented by computing hardware, for example, by one or more processors or computers. A processor or computer may be implemented by one or more processing elements, such as an array of logic gates, a controller and an arithmetic logic unit, a digital signal processor, a microcomputer, a programmable logic controller, a field-programmable gate array, a programmable logic array, a microprocessor, or any other device or combination of devices that is configured to respond to and execute instructions in a defined manner to achieve a desired result. In one example, a processor or computer includes, or is connected to, one or more memories storing instructions or software that are executed by the processor or computer. Hardware components implemented by a processor or computer may execute instructions or software, such as an operating system (OS) and one or more software applications that run on the OS, to perform the operations described in this application. The hardware components may also access, manipulate, process, create, and store data in response to execution of the instructions or software. For simplicity, the singular term “processor” or “computer” may be used in the description of the examples described in this application, but in other examples multiple processors or computers may be used, or a processor or computer may include multiple processing elements, or multiple types of processing elements, or both. For example, a single hardware component or two or more hardware components may be implemented by a single processor, or two or more processors, or a processor and a controller. One or more hardware components may be implemented by one or more processors, or a processor and a controller, and one or more other hardware components may be implemented by one or more other processors, or another processor and another controller. One or more processors, or a processor and a controller, may implement a single hardware component, or two or more hardware components. A hardware component may have any one or more of different processing configurations, examples of which include a single processor, independent processors, parallel processors, single-instruction single-data (SISD) multiprocessing, single-instruction multiple-data (SIMD) multiprocessing, multiple-instruction single-data (MISD) multiprocessing, and multiple-instruction multiple-data (MIMD) multiprocessing. 
     The methods illustrated in  FIGS. 1 to 26  that perform the operations described in this application are performed by computing hardware, for example, by one or more processors or computers, implemented as described above executing instructions or software to perform the operations described in this application that are performed by the methods. For example, a single operation or two or more operations may be performed by a single processor, or two or more processors, or a processor and a controller. One or more operations may be performed by one or more processors, or a processor and a controller, and one or more other operations may be performed by one or more other processors, or another processor and another controller. One or more processors, or a processor and a controller, may perform a single operation, or two or more operations. 
     Instructions or software to control computing hardware, for example, one or more processors or computers, to implement the hardware components and perform the methods as described above may be written as computer programs, code segments, instructions or any combination thereof, for individually or collectively instructing or configuring the one or more processors or computers to operate as a machine or special-purpose computer to perform the operations that are performed by the hardware components and the methods as described above. In one example, the instructions or software include machine code that is directly executed by the one or more processors or computers, such as machine code produced by a compiler. In another example, the instructions or software includes higher-level code that is executed by the one or more processors or computer using an interpreter. The instructions or software may be written using any programming language based on the block diagrams and the flow charts illustrated in the drawings and the corresponding descriptions in the specification, which disclose algorithms for performing the operations that are performed by the hardware components and the methods as described above. 
     The instructions or software to control computing hardware, for example, one or more processors or computers, to implement the hardware components and perform the methods as described above, and any associated data, data files, and data structures, may be recorded, stored, or fixed in or on one or more non-transitory computer-readable storage media. Examples of a non-transitory computer-readable storage medium include read-only memory (ROM), random-access memory (RAM), flash memory, CD-ROMs, CD-Rs, CD+Rs, CD-RWs, CD+RWs, DVD-ROMs, DVD-Rs, DVD+Rs, DVD-RWs, DVD+RWs, DVD-RAMs, BD-ROMs, BD-Rs, BD-R LTHs, BD-REs, magnetic tapes, floppy disks, magneto-optical data storage devices, optical data storage devices, hard disks, solid-state disks, and any other device that is configured to store the instructions or software and any associated data, data files, and data structures in a non-transitory manner and provide the instructions or software and any associated data, data files, and data structures to one or more processors or computers so that the one or more processors or computers can execute the instructions. In one example, the instructions or software and any associated data, data files, and data structures are distributed over network-coupled computer systems so that the instructions and software and any associated data, data files, and data structures are stored, accessed, and executed in a distributed fashion by the one or more processors or computers. 
     While this disclosure includes specific examples, it will be apparent after an understanding of the disclosure of this application that various changes in form and details may be made in these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be considered in a descriptive sense only, and not for purposes of limitation. Descriptions of features or aspects in each example are to be considered as being applicable to similar features or aspects in other examples. Suitable results may be achieved if the described techniques are performed in a different order, and/or if components in a described system, architecture, device, or circuit are combined in a different manner, and/or replaced or supplemented by other components or their equivalents. Therefore, the scope of the disclosure is defined not by the detailed description, but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents are to be construed as being included in the disclosure.