Electronic eyeglasses

Abstract

To provide a technique of precisely measuring a distance in a wide range regardless of scenes in which an apparatus is being used.SOLUTION: Electronic eyeglasses have a variable focal lens with an index of refraction changed from for myopia to for hyperopia in response to an applied voltage, and includes: a controller for controlling application of voltages on the variable focal lens; and a short-distance sensor for measuring a short-distance range distant from the variable focal lens by less than a predetermined threshold value and outputting the distance to a target in the short-distance range as a distance measured value. The controller applies a voltage to the variable focal lens when the short-distance sensor outputs the distance measured value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to electronic glasses equipped with a distance measuring sensor.

Background Art

[0002] Among portable information processing terminals (portable information processing terminals, portable terminals) typified by smartphones, there are those equipped with a plurality of cameras on the same surface. For example, a wide-angle camera and an ultra-wide-angle camera. Using the images captured by each camera, AR (Augmented Reality) processing or the like for superimposing visual information on the real world is performed. For such AR processing, highly accurate distance measurement is essential.

[0003] As distance measuring sensors, there are technologies called TOF (Time Of Flight) and LiDAR (Light Detection and Ranging). For example, Patent Document 1 discloses a technology for mounting a plurality of homogeneous LiDARs on a vehicle such as an automobile.

[0004] Also, in a portable terminal, a distance measuring sensor is also used for recognizing gesture instructions. For example, Patent Document 2 discloses a technology for installing a distance measuring sensor at the center of the glasses portion in a head-mounted image display device for distance measurement.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the technology disclosed in Patent Document 1, a plurality of LIDARs of the same type are provided. However, the measurement range of LIDAR is limited depending on the sensors and methods used. When the measurement range and the usage scene of the obtained distance values are substantially limited, such as in the case of automobiles, there is no problem. However, in the case of mobile terminals, etc., the usage methods of users vary widely. In such a case, accurate measurement may not be possible depending on the distance to the object. Furthermore, in mobile terminals, etc., there are restrictions on the size and weight of the device, and sensors with a complex configuration or large sensors cannot be mounted.

[0007] The present invention has been made in view of the above points, and an object thereof is to provide a technology for accurately measuring a wide range of distances regardless of the usage scene of the device.

Means for Solving the Problems

[0008] The present invention is an electronic glasses including a variable focus lens whose refractive index is changed from a refractive index for hyperopia to a refractive index for myopia by applying a voltage, a control device for controlling the application of the voltage to the variable focus lens, and a short-distance sensor for measuring a short-distance range in which the distance from the variable focus lens is less than a predetermined threshold value and outputting the distance to an object included in the short-distance range as a measured distance value. The control device is characterized in that when the short-distance sensor outputs the measured distance value, a voltage is applied to the variable focus lens.

Effects of the Invention

[0009] According to the present invention, a wide range of distances can be accurately measured regardless of the usage scene of the device. Problems, configurations, and effects other than those described above will be clarified by the description of the following embodiments.

Brief Description of the Drawings

[0010]

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Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the same reference numerals in the drawings indicate the same functions and processes. In this embodiment, by providing the following technologies, high-precision distance measurement is enabled. This distance measurement technology contributes to "9. Build the foundation of industry and technological innovation" among the Sustainable Development Goals (SDGs) proposed by the United Nations.

[0012] <<First Embodiment>> The first embodiment of the present invention will be described. In this embodiment, a mobile terminal equipped with a plurality of cameras with different shooting distances on the same surface will be taken as an example for explanation. Hereinafter, in this embodiment, a smartphone will be taken as an example of the mobile terminal for explanation. The smartphone of this embodiment is equipped with a plurality of distance sensors with different measurable distance ranges (distance measurement ranges) on the same surface as the surface equipped with the plurality of cameras. Then, these distance sensors are selectively used according to the distance to the measurement target.

[0013] First, the outline of this embodiment and the appearance of the smartphone 100 will be described. FIG. 1(a) is a rear view of the smartphone 100, FIG. 1(b) is a front view, and FIG. 1(c) is a side view. Here, the description will focus on the configuration related to this embodiment.

[0014] The smartphone 100 includes a case 109 that houses each part of the smartphone 100 inside. In the following description, the up-down direction and the left-right direction are as shown in the drawing.

[0015] As shown in FIG. 1(a), the smartphone 100 includes a first camera 135, a second camera 136, a first distance sensor 155, and a second distance sensor 156 on the back side. Also, as shown in FIG. 1(b), a display 131, operation keys 121, etc. are provided on the front side. Here, the shooting range (shooting field of view 135v) of the first camera 135 is indicated by a dashed line.

[0016] Note that the display 131 is a touch screen that combines a display device such as a liquid crystal panel and a position input device such as a touch pad. It also functions as a viewfinder for the first camera 135 and the second camera 136.

[0017] Also, in the present embodiment, as shown in FIG. 1(a), the first distance sensor 155 and the second distance sensor 156 are respectively arranged at the same position in the longitudinal direction (vertical direction) of the smartphone 100, approximately, with the first distance sensor 155 corresponding to the first camera 135 and the second distance sensor 156 corresponding to the second camera 136.

[0018] The first distance sensor 155 is a medium-distance sensor with a medium distance as the ranging range. The second distance sensor 156 is a short-distance sensor with a short distance as the ranging range. The ranging ranges of the first distance sensor 155 and the second distance sensor 156 will be described with reference to FIG. 1(c).

[0019] As shown in this figure, the direction of the ranging center (ranging direction 155c) of the medium-distance sensor (first distance sensor 155) in the present embodiment is the same as the optical axis direction of the first camera 135, and the ranging direction 156c of the short-distance sensor (second distance sensor 156) is the same as the optical axis direction of the second camera 136. Thereby, the distance to the object in the image acquired by each camera can be accurately obtained.

[0020] [Hardware Configuration] Next, the hardware configuration of the smartphone 100 of the present embodiment will be described. FIG. 2 is a hardware configuration diagram of the smartphone 100 of the present embodiment.

[0021] As shown in this figure, the smartphone 100 includes a main processor 101, a system bus 102, a storage device 110, an operation device 120, an image processing device 130, an audio processing device 140, a sensor 150, a communication device 160, an expansion interface (I / F) 170, and a timer 180.

[0022] The main processor 101 is a main control unit that controls the entire smartphone 100 according to a predetermined program. The main processor 101 is implemented by a CPU (Central Processor Unit) or a microprocessor unit (MPU). The main processor 101 performs processing according to the clock signal measured and output by the timer 180.

[0023] The system bus 102 is a data communication path for performing data transmission and reception between the main processor 101 and each part within the smartphone 100.

[0024] The storage device 110 stores data necessary for processing by the main processor 101, data generated by the processing, and the like. The storage device 110 includes a RAM 103, a ROM 104, and a flash memory 105.

[0025] The RAM 103 is a program area when executing a basic operation program and other application programs. Also, the RAM 103 is a temporary storage area that temporarily holds data as needed when executing various application programs. The RAM 103 may be integrally configured with the main processor 101.

[0026] The ROM 104 and the flash memory 105 store each operation setting value of the smartphone 100, information of the user of the smartphone 100, and the like. These may store still image data, moving image data, etc. photographed by the smartphone 100. Further, it is assumed that the smartphone 100 can expand its functions by downloading a new application program from an application server via the Internet. At this time, the downloaded new application program is stored therein. The main processor 101 expands the new application program stored therein into the RAM 103 and executes it, whereby the smartphone 100 can realize various functions. Note that devices such as an SSD (Solid State Drive) and an HDD (Hard Disc Drive) may be used instead of these.

[0027] The operation device 120 receives an input of an operation instruction for the smartphone 100. In the present embodiment, it includes operation keys 121 such as a power key, a volume key, and a home key. Further, it includes a touch sensor 122 that receives an operation instruction by a touch pad. This touch sensor 122 is disposed on the display 131, which will be described later, as a touch panel. Note that the smartphone 100 of the present embodiment does not necessarily include all of these operation devices 120. The power key may be disposed, for example, on the upper surface, side surface, etc. of the case 109.

[0028] Further, an input of an instruction may be received via a keyboard or the like connected to the expansion interface 170, which will be described later. Further, an operation of the smartphone 100 may be received via a separate information processing terminal device connected by wired communication or wireless communication.

[0029] The image processing device 130 includes an image (video) processor, and includes a display 131, a first camera 135 that is a first image acquisition unit, a second camera 136 that is a second image acquisition unit, and a third camera 137. The third camera 137 is provided on the front side.

[0030] The display 131 is a display device such as a liquid crystal panel, etc., and presents the image data processed by the image processor to the user of the smartphone 100. In addition, when the mobile terminal is a head mounted display (HMD), the display 131 may be a transmissive type.

[0031] The images acquired by the first camera 135, the second camera 136, and the third camera 137 are processed by an image (video) signal processor or the main processor 101, and further, an object generated by the main processor 101, etc. is superimposed and output to the display 131.

[0032] The first camera 135 and the second camera 136 are rear cameras (out cameras) that acquire images around the smartphone 100. On the other hand, the third camera 137 acquires images in a direction different from that of the first camera 135 and the second camera 136. For example, it is a front camera (in camera) that photographs the user's face and eyes. In addition, when the mobile terminal is an HMD, the third camera 137 functions as, for example, a gaze detection sensor.

[0033] The audio processing device 140 includes an audio signal processor that processes audio, and includes a speaker 141 that is an audio output unit and a microphone 143 that is an audio input unit. The speaker 141 is disposed, for example, above the center of the front surface of the case 109 and at the lower rear of the display 131. The speaker 141 disposed at the upper front of the case 109 is a monaural speaker and is used during a voice call. The speaker 141 disposed at the lower rear of the case 109 is a stereo speaker and is used during video playback, etc. Further, the microphone 143 is disposed, for example, on the lower surface of the case 109.

[0034] Sensor 150 is a group of sensors for detecting the state of smartphone 100. In the present embodiment, it includes distance sensor 159 including the above-described two sensors (first distance sensor 155 and second distance sensor 156), GPS (Global Positioning System) receiver 151, gyro sensor 152, geomagnetic sensor 153, and acceleration sensor 154. These sensors detect the position, movement, inclination, azimuth, etc. of smartphone 100. Also, distance sensor 159 is a depth sensor and a ranging device for acquiring distance information from smartphone 100 to an object. Hereinafter, in this specification, when there is no need to particularly distinguish between first distance sensor 155 and second distance sensor 156, it is represented by distance sensor 159. Also, details of distance sensor 159 will be described later. Note that other sensors may further be provided.

[0035] Communication device 160 is a communication processor that performs communication processing. For example, it includes LAN (Local Area Network) communication unit 161, telephone network communication unit 162, and BT (Bluetooth (registered trademark)) communication unit 163. LAN communication unit 161 is connected to a wireless access point for Internet wireless communication by wireless communication to perform data transmission and reception. Telephone network communication unit 162 performs telephone communication (call) and data transmission and reception by wireless communication with a base station of a mobile phone communication network. BT communication unit 163 is an interface for communicating with an external device according to the Bluetooth standard. LAN communication unit 161, telephone network communication unit 162, and BT communication unit 163 each include an encoding circuit, a decoding circuit, an antenna, etc. Communication device 160 may further include an infrared communication unit or the like.

[0036] The expansion interface 170 is a group of interfaces for expanding the functions of the smartphone 100. In this embodiment, it includes a charging terminal, a video / audio interface, a USB (Universal Serial Bus) interface, a memory interface, etc. The video / audio interface performs functions such as input of video signals / audio signals from an external video / audio output device and output of video signals / audio signals to an external video / audio input device. The USB interface connects a keyboard and other USB devices. The memory interface connects a memory card and other memory media to perform data transmission and reception. The USB interface is arranged, for example, on the lower surface of the case 109.

[0037] In addition, it may also be provided with a fingerprint sensor arranged on the back surface of the case 109, an LED arranged above the front surface of the case 109 and the display 131, etc.

[0038] Note that the configuration example of the smartphone 100 shown in FIG. 2 includes many configurations that are not essential for this embodiment, but the effects of this embodiment will not be impaired even if these configurations are not provided.

[0039] [Functional Blocks] Next, the functional configuration of the smartphone 100 of this embodiment will be described. The smartphone 100 of this embodiment changes the distance sensor 159 to be used according to the distance of the measurement target. Regarding the functional configuration of the smartphone 100 of this embodiment, the description will focus on the configurations related to this embodiment.

[0040] FIG. 3 is a functional block diagram of the smartphone 100 of this embodiment. As shown in this figure, the smartphone 100 includes an overall control unit 211, a distance measurement control unit 212, a display control unit 218, and a distance value database (DB) 219. The distance measurement control unit 212 includes a distance sensor activation unit 213 and a distance signal processing unit 214. Each function is realized by the main processor 101 loading the program stored in the storage device 110 into the RAM 103 and executing it. Also, the distance value DB 219 is stored in the storage device 110.

[0041] The overall control unit 211 controls the operation of the entire smartphone 100. Also, the display control unit 218 controls the display on the display 131. In the present embodiment, the display is controlled using the distance value described later obtained under the control of the distance measurement control unit 212.

[0042] The distance measurement control unit 212 controls the distance measurement by the distance sensor 159. In the present embodiment, it controls the activation and driving of the first distance sensor 155 and the second distance sensor 156, and acquires a distance value (distance measurement value) as the distance to the object. In the present embodiment, this is achieved by controlling the distance sensor activation unit 213 and the distance signal processing unit 214.

[0043] The distance sensor activation unit 213 activates the first distance sensor 155 and the second distance sensor 156. In the present embodiment, when the smartphone 100 is activated or an instruction to activate the distance sensor is received from the user, first, the first distance sensor 155, which is a medium-distance sensor, is operated. And when an NG signal is received from the first distance sensor 155, the second distance sensor 156 is operated. The NG signal will be described later.

[0044] When the sensor signal (distance value) received from the first distance sensor 155 or the second distance sensor 156 is not an NG signal, the distance signal processing unit 214 outputs the sensor signal as the distance measurement value of the distance sensor 159. Also, the distance signal processing unit 214 stores the distance value in the distance value DB219 of the storage device 110 in association with, for example, the measurement time and the two-dimensional position.

[0045] [Distance Sensor] Here, the first distance sensor 155 and the second distance sensor 156 will be further described. In the present embodiment, as shown in FIG. 4(a), the first distance sensor 155 has a range (first ranging range 155d) in which the shooting distance 135d of the first camera 135 can be measured. The shooting distance and the ranging range include infinity. Also, as shown in FIG. 4(b), a first ranging area 155v including the shooting field of view 135v of the first camera 135 can be measured. As shown in FIG. 4(c), the second distance sensor 156 has a range (second ranging range 156d) in which the shooting distance 136d of the second camera 136 can be measured. Also, as shown in FIG. 4(d), a second ranging area 156v including the shooting field of view 136v of the second camera 136 can be measured.

[0046] The shooting field of view 135v of the first camera 135 and the first ranging area 155v of the first distance sensor 155 are pre-associated and stored in the storage device 110. Thereby, the distance value of the object corresponding to each pixel position of the first camera 135 can be calculated. The same applies to the second camera 136 and the second distance sensor 156.

[0047] To realize these, in the present embodiment, TOF-based LiDARs are used as the first distance sensor 155 and the second distance sensor 156. The TOF-based LiDAR emits laser light from a laser light source and measures the distance from the sensor to the object using the light reflected by the object.

[0048] The first ranging range 155d of the first distance sensor 155 is a medium distance from the smartphone 100, for example, in the range of 30 cm to 5 m from the smartphone 100. When the object is within the first ranging range 155d, the first distance sensor 155 outputs the distance value between the first distance sensor 155 and the object as a ranging value. On the other hand, when the object could not be measured at a closer distance than the first ranging range 155d, an NG value is output. In the case of a distance farther than the first ranging range 155d, it is assumed that the measurement was possible at 5 m or more.

[0049] The first distance sensor 155 is realized by, for example, a direct Time of Flight (TOF) type Light Detection And Ranging (LiDAR). The direct TOF method is a method of irradiating pulsed laser light and observing the time taken for reflection. According to the direct TOF method, it is possible to measure the distance to an object about 5 m ahead both indoors and outdoors.

[0050] Fig. 5(a) shows an overview of the first distance sensor 155. As shown in this figure, the first distance sensor 155 includes a light emitting unit 310 having a laser light source that emits laser light, and a light receiving unit 340 having a light receiving element that receives the laser light reflected by the object 329. The light emitting unit 310 irradiates pulsed laser light 351, and the light receiving element of the light receiving unit 340 receives the reflected light 352 by the object 329. In the first distance sensor 155, from this pulse time difference, the time required for the pulsed laser light to travel to and fro is calculated, and the distance is estimated.

[0051] The second ranging range 156d of the second distance sensor 156 is a short-distance range around the smartphone 100, for example, a range within 30 cm from the smartphone 100. When the object is within the second ranging range 156d, the second distance sensor 156 outputs the distance value between the second distance sensor 156 and the object as a ranging value. On the other hand, when the object is outside the second ranging range 156d, an NG value is output.

[0052] The second distance sensor 156 is realized by, for example, an indirect TOF type LiDAR. The indirect TOF method is a method of converting the phase difference of the frequency of light into a time difference and multiplying by the speed to calculate the distance to the target.

[0053] FIG. 5(b) shows an overview of the second distance sensor 156. As shown in this figure, the second distance sensor 156 includes a light emitting unit 310 that emits laser light, and a light receiving unit 340 that receives the laser light reflected by the object 329. In the second distance sensor 156, laser light (emitted light 353) having periodic pulses is irradiated from the light emitting unit 310, and the reflected light 354 is received by the light receiving unit 340. In the second distance sensor 156, the distance is estimated from the phase difference between the emitted light 353 and the reflected light 354.

[0054] Note that the first distance sensor 155 and the second distance sensor 156 are not limited to these. For example, any distance sensor that can measure a predetermined distance measurement range, such as obtaining the distance by machine learning the size of a subject from a millimeter wave radar or a camera image, may be used.

[0055] As described above, the first distance sensor 155 and the second distance sensor 156 each measure a first distance measurement region 155v and a second distance measurement region 156v, which are predetermined two-dimensional distance measurement regions. Hereinafter, an example of a distance measurement method for a two-dimensional distance measurement region of a LiDAR used as the first distance sensor 155 and the second distance sensor 156 will be described with reference to FIGS. 6(a) to 6(d).

[0056] As shown in FIG. 6(a), the light emitting unit 310 of the LiDAR includes a laser light source 311, a collimating lens 312, a condenser lens 313, and a MEMS (Micro Electro Mechanical Systems) element 314. The elements and optical components on the light receiving side are omitted.

[0057] The LiDAR collimates the light emitted from the laser light source 311 with the collimating lens 312 and condenses it with the condenser lens 313. Thereafter, the MEMS mirror 331 scans in a first axis and a direction orthogonal to the first axis, thereby detecting the distance to an object (object 329) within the range of the two-dimensional distance measurement region 320.

[0058] The configuration of the MEMS element 314 will be described with reference to FIG. 6(b). The MEMS element 314 includes a MEMS mirror 331 that reflects light, an inner coil 332 disposed on the outer periphery of the MEMS mirror 331, an inner torsion bar 333, an outer coil 334, and an outer torsion bar 335.

[0059] When an external magnetic field is applied and a current is passed through the inner coil 332, a torque (Lorentz force) that rotates the MEMS mirror 331 in the AA direction in the figure acts, and at the same time, the elastic force of the torsion spring by the inner torsion bar 333 acts in the opposite direction, and the MEMS mirror 331 vibrates in the AA direction within a predetermined angle range. Also, when a current is passed through the outer coil 334, a torque that rotates the inner coil 332 and the MEMS mirror 331 in the BB direction in the figure acts, and at the same time, the elastic force by the outer torsion bar 335 acts in the opposite direction, and the MEMS mirror 331 vibrates in the BB direction within a predetermined angle range.

[0060] As a result, as shown in FIG. 6(c), the LiDAR realizes a horizontal scan within a predetermined range (AA direction in the figure) and a vertical scan within a predetermined range (BB direction in the figure). During this time, by calculating the distance value at a predetermined time interval, as shown in FIG. 6(d), the distance values of each unit area in the range corresponding to the two-dimensional distance measurement area 320 are obtained.

[0061] By associating the distance value detection unit with the pixel positions of the first camera 135 and the second camera 136, the distance measurement result can be effectively used during image processing of the images captured by these imaging devices.

[0062] In this case, for example, the first data that associates the imaging field of view 135v of the first camera 135 with the first distance measurement area 155v and the second data that associates the imaging field of view 136v of the second camera 136 with the second distance measurement area 156v are stored in the storage device 110 in advance. Then, the distance signal processing unit 214 calculates the distance values of the areas corresponding to the pixel positions of the first camera 135 as needed, and obtains the distance values for each pixel of the image acquired by the first camera 135. The same applies to the image acquired by the second camera 136.

[0063] [Process Flow] Next, the flow of the distance measurement process by the distance measurement control unit 212 of the present embodiment will be described. FIG. 7 shows the process flow of the distance measurement process of the present embodiment. This process is started, for example, when an instruction to start distance measurement is received from the user or when the smartphone 100 is activated. Also, in the present embodiment, the distance measurement result is used together with the shooting results by each camera. Therefore, the distance measurement process may be started, for example, when the first camera 135 or the second camera 136 is activated.

[0064] And this process is repeatedly performed at a predetermined time interval. This time interval is set to be at least the time required to scan the distance measurement area 320 once.

[0065] Hereinafter, in the present embodiment, the case where the first distance sensor 155, which is a medium - distance sensor, is preferentially operated will be described as an example.

[0066] The distance sensor activation unit 213 starts the operation of the first distance sensor 155 (step S1101). Thereby, distance measurement by the first distance sensor 155 is performed (step S1102).

[0067] The distance signal processing unit 214 determines whether the first distance sensor 155 can measure the distance (step S1103). Here, it is determined whether the sensor signal received from the first distance sensor 155 is a distance value or an NG signal. In the present embodiment, distance measurement of the first distance measurement area 155v is performed. For example, it is determined using a sensor signal indicating the distance measurement result of a predetermined area (discrimination area) such as a predetermined range at the center of the first distance measurement area 155v. For example, if all the sensor signals in this discrimination area are NG values, it is determined that the measurement cannot be performed. The discrimination criteria are predetermined and stored in the storage device 110 or the like.

[0068] When it is determined that measurement is possible (S1103; Yes), the distance signal processing unit 214 stores the distance value, which is the sensor signal, in association with the acquisition time (step S1104) and ends the process. Note that information (position information) for specifying the position of the first distance measurement area 155v can be specified from the acquisition time by the scanning mechanism of the MEMS element 314. Therefore, it may be stored in association with the position information of the first distance measurement area.

[0069] On the other hand, when measurement is not possible (S1103; No), the distance sensor activation unit 213 stops the operation of the first distance sensor 155 and starts the operation of the second distance sensor 156 (step S1105). Thereby, distance measurement is performed by the second distance sensor 156 (step S1106).

[0070] The distance signal processing unit 214 determines whether measurement is possible with the second distance sensor 156 (step S1107). The determination method is the same as that for the first distance sensor 155.

[0071] When it is determined that measurement is possible (S1107; Yes), the process proceeds to step S1104. On the other hand, when measurement is not possible (S1107; No), the distance measurement control unit 212 performs NG processing (step S1108) and ends the process. Note that the NG processing is, for example, displaying a message indicating that distance value measurement is impossible on the display 131, outputting a predetermined sound from the speaker 141, or the like.

[0072] As described above, the smartphone 100 according to the present embodiment includes a distance measurement device (distance sensor 159) capable of measuring the first distance measurement range 155d and a second distance measurement range 156d different from the first distance measurement range 155d, and a processing unit (distance signal processing unit 214) that determines the distance to the object from the distance measurement result of the distance sensor 159 and outputs it as a distance measurement value.

[0073] As a result, in devices such as the smartphone 100, which are assumed to have various usage methods, it is possible to accurately measure distances around the device regardless of a single measurement range. That is, regardless of how the smartphone 100 is used, it is possible to accurately obtain the distance values within the shooting range of the camera of the smartphone 100. Of course, the first camera 135 and the second camera 136 may be switched in accordance with the switching of the distance sensor. Also, when the user selects the camera to be used, the first distance sensor 155 and the second distance sensor 156 may be switched according to that operation.

[0074] Further, the first measurement range 155d includes the shooting distance 135d of the first camera 135, and the second measurement range 156d includes the shooting distance 136d of the second camera 136. Therefore, according to the present embodiment, it is possible to accurately measure distances over the entire shooting range of the cameras provided in the device (smartphone 100) on which the distance sensor 159 is mounted.

[0075] And in the smartphone 100, various processes can be performed using the obtained distance values. For example, it is possible to accurately perform focusing during camera shooting, and also when performing virtual reality display, it is possible to accurately execute occlusion for grasping the front-back relationship between an object in the real space and a virtual object, and a more natural virtual reality display can be realized. In the present embodiment, for example, the display control unit 218 determines the front-back relationship between an object in the real space and a virtual object using the distance value, specifies the occlusion area, and performs display.

[0076] Also, the distance sensor 159 of the smartphone 100 according to the present embodiment includes a first distance sensor 155 that measures the first measurement range 155d and obtains a measurement value, and a second distance sensor 156 that measures the second measurement range 156d and obtains a measurement value. And it includes a distance sensor activation unit 213 that activates the second distance sensor 156 when a measurement value by the first distance sensor 155 cannot be obtained.

[0077] As described above, in this embodiment, first, the first distance sensor 155, which is a medium-distance sensor, is activated. If the measurement range of the first distance sensor 155 (first measurement range 155d) is not reached, the second distance sensor 156 is activated. In the case of the smartphone 100, since the medium-distance sensor is generally used frequently, by configuring it in this way, unnecessary use of the light-emitting device of the distance sensor 159 can be suppressed, and battery consumption can be suppressed.

[0078] Further, in this embodiment, the optical axis direction of the corresponding camera is aligned with the distance measurement direction of the distance sensor 159. Therefore, the distance value acquired by the distance sensor 159 can be accurately associated with the pixel value acquired by each camera. Thereby, the accuracy of augmented reality processing and the like can be improved.

[0079] Note that in the above embodiment, the first distance sensor 155 and the second distance sensor 156 are each activated by software to switch the distance sensor to be used, but the present invention is not limited to this. For example, a hardware switching switch may be provided, and the distance sensor to be used may be switched by outputting a switching instruction to the switching switch by software.

[0080] <Modification 1> In the above embodiment, first, the first distance sensor 155, which is a medium-distance sensor, is activated, but the present invention is not limited to this. For example, depending on the usage environment, the second distance sensor 156, which is a short-distance sensor, may be preferentially activated. Further, a configuration may be adopted in which the user can determine which one is preferentially activated.

[0081] Furthermore, both distance sensors may be activated simultaneously. The processing flow in this case is shown in FIG. 8. The trigger and execution frequency of this processing are the same as those of the distance measurement processing in the above embodiment.

[0082] The distance sensor activation unit 213 activates the first distance sensor 155 and the second distance sensor 156 (step S1201). Thereby, distance measurement is performed by both distance sensors (step S1202).

[0083] The distance signal processing unit 214 determines which distance value of the distance sensors to adopt (step S1203). Here, it discriminates using the sensor signals of the discrimination region obtained from both distance sensors. That is, it adopts the distance value of the side where the sensor signal of the discrimination region is not an NG signal.

[0084] The distance signal processing unit 214 stores the distance value obtained from the distance sensor determined to be adopted in association with the acquisition time (step S1204), and ends the processing.

[0085] By activating both sensors and performing the processing in this way, since sensor signals have already been obtained from both sensors at the point of determining which ranging result of the distance sensors to adopt, the processing speed is increased.

[0086] <Modification Example 2> Also, in the above embodiment, the ranging direction 156c of the second distance sensor 156, which is a short-distance sensor, is aligned with the optical axis direction of the second camera 136. However, the ranging direction 156c of the second distance sensor 156 is not limited to this. For example, as shown in Fig. 9(a), the ranging direction 156c of the second distance sensor 156 may be directed downward. That is, the second distance sensor 156 may be arranged in a direction where its ranging direction 156c has a predetermined angle θ with respect to the vertical direction.

[0087] When the mobile terminal is the smartphone 100, the range measured by the second distance sensor 156, which is a short-distance sensor, is often below the smartphone 100 such as in the hand. Also, in the second camera 136 for short-distance shooting, it is often the case that a QR code (registered trademark) is shot, and in order to read this QR code, it is often the case that the QR code is first aligned with the central part of the smartphone 100. Therefore, by directing the ranging direction 156c of the second distance sensor 156 downward, first the distance of the QR code is measured, and by aligning the position of the camera mounted on the upper part of the smartphone 100, the short distance can be accurately measured.

[0088] In the smartphone 100, first, the distance sensor 159 measures the distance to the shooting target, and depending on the result, it may be determined whether to activate the first camera 135 for shooting at a medium distance or the second camera 136 for shooting at a short distance. By configuring as in this modified example, in such a case, the smartphone 100 can accurately measure medium and short distances while being held in a substantially vertical manner. And based on the highly accurate measurement result, the camera to be activated can be determined. As a result, the probability of activating the desired camera increases, and the usability of the smartphone 100 is improved.

[0089] <Modified Example 3> Also, the arrangement of the second distance sensor 156 is not limited to the position in the above embodiment. For example, as shown in FIG. 9(b), it may be arranged below the smartphone 100. In this figure, an example of arranging it at the center of the lower part of the smartphone 100 is shown. As described above, since the range for distance measurement by the short-distance sensor is often downward, it is more reasonable.

[0090] Furthermore, at this time, as shown in FIG. 9(c), the distance measurement direction 156c of the second distance sensor 156 may be directed downward. For the same reason as above, the usability is improved.

[0091] <Modified Example 4> In the above embodiment, the case where the MEMS-based LiDAR is used for the distance sensor 159 has been described as an example. However, the distance sensor 159 is not limited to this method. For example, it may be a pattern emission method.

[0092] The configuration of the distance sensor 159 in the case of the pattern emission method is shown in FIG. 10. In the case of the pattern emission method, the distance sensor 159 includes a laser light source 311 and a diffraction grating 361. Components such as a collimating lens are omitted. In this method, the diffraction grating 361 diffracts the laser light incident on the diffraction grating 361 and changes it into various shapes and irradiation patterns 363. Then, in the light receiving unit 340 having a light receiving element, the distance of each point in the distance measurement area 320 is calculated from the time until the emitted light returns and the distortion of the irradiation pattern 363. By switching the spread angle of the irradiation pattern and the power of the irradiated laser by moving the positions of the lens and the diffraction grating (not shown), it is possible to switch the measurement range.

[0093] <Modification Example 5> In addition, in the above embodiment, the case where the mobile terminal is the smartphone 100 has been described as an example, but the mobile terminal is not limited to this. For example, it may be an HMD 100h.

[0094] An example of the arrangement of the first distance sensor 155 and the second distance sensor 156 in this case is shown in FIG. 11(a). As shown in this figure, for example, the first distance sensor 155 is installed at the end in the width direction of the upper frame of the lens (display). Also, the second distance sensor 156 is installed at the center of the upper frame.

[0095] In this case, the distance measurement direction 155c of the first distance sensor 155 and the distance measurement direction 156c of the second distance sensor 156 may be the same. Also, as shown in FIG. 11(b), the distance measurement direction 156c of the second distance sensor 156 may be downward, inclined at a predetermined angle from the vertical direction.

[0096] In the case of the HMD 100h, the distance measurement direction is substantially the user's line-of-sight direction. When looking at a short distance, the user's line-of-sight direction is often downward. Therefore, by setting the distance measurement direction 156c of the second distance sensor 156 downward, it is possible to detect the distance in a direction more along the user's line-of-sight direction.

[0097] Note that in the case of the HMD 100h and when the distance measurement direction of the second distance sensor 156 is arranged downward as shown in FIG. 11(b), the line-of-sight direction of the user may be detected, and accordingly, the distance sensor 159 to be used may be determined or changed.

[0098] For line-of-sight detection, for example, the shooting result of the third camera 137 which is an in-camera is used. The third camera 137 shoots the user's eyes, and the line-of-sight direction of the user is detected by analyzing the image by a conventional method. Then, when the line-of-sight direction of the user matches the distance measurement direction 156c of the second distance sensor 156 within a predetermined range, the distance measurement result of the second distance sensor 156 is used as a measured value (distance value).

[0099] <Modification Example 6> Note that when the mobile terminal is the HMD 100h, the second distance sensor 156 which is a proximity sensor may be arranged on the temple 108 of the glasses. The arrangement modes in this case are shown in FIGS. 12(a) and 12(b). This is for detecting an instruction by a gesture.

[0100] For example, as shown in FIG. 12(c), a gesture operation xyz coordinate system is defined, and the distance value of each unit area within the second distance measurement area 156v is measured by the second distance sensor 156 to detect a gesture operation.

[0101] Examples of menu displays in this case are shown in FIGS. 13(a) and 13(b). Here, the menu is displayed as if it is displayed in the depth direction (x-axis direction). Also, for example, the menu can be scrolled by moving a hand in the front-back direction (x-axis direction) on the side of the face. The menu display is controlled by the display control unit 218.

[0102] For example, when a menu located at the center position across the user's head is selected, the display mode (e.g., color) changes. The user can make a selection by bringing their hand closer in the direction of the Z-axis or by touching the touch sensor provided in the HMD100h. When the HMD100h receives a selection instruction from the user, it determines that the menu displayed at the center position across the head at that time has been selected and performs processing.

[0103] As a result, gestures as operations of the HMD100h can be performed on the side, and with gestures, the field of view is not obstructed and the usability can be improved. Also, by providing the above-described menu display as a new user interface, a display highly related to hand movements can be realized and the operability is improved.

[0104] At this time, as in the previous modification example, further, a second distance sensor 156 which is a proximity sensor may be arranged at the upper part of the front center.

[0105] <<Second Embodiment>> Next, a second embodiment of the present invention will be described. The smartphone 100 of the first embodiment includes a plurality of distance sensors 159 with different ranging ranges. On the other hand, the smartphone 100 of the present embodiment includes a distance sensor with a variable ranging range, and switches and uses the ranging range according to the distance to the target.

[0106] Hereinafter, the present embodiment will be described with a focus on configurations different from those of the first embodiment.

[0107] FIG. 14(a) is a rear view of the smartphone 100a, and FIG. 1(b) is a side view. Here, the description will focus on the configurations related to the present embodiment.

[0108] As shown in FIG. 14(a), the smartphone 100a includes a first camera 135, a second camera 136, and a variable distance sensor 157 on the rear side. Other external configurations are the same as those of the first embodiment.

[0109] In addition, in the present embodiment, as shown in FIG. 14(a), the variable distance sensor 157 is disposed at an intermediate position in the longitudinal direction (vertical direction) of the smartphone 100a between the first camera 135 and the second camera 136. Further, as shown in FIG. 14(b), the distance measurement direction 157c of the variable distance sensor 157 is the same as the optical axis direction of the camera.

[0110] The hardware configuration of the smartphone 100a of the present embodiment is shown in FIG. 15. In this figure, the same components as those in the first embodiment are denoted by the same reference numerals. As shown in this figure, the smartphone 100a of the present embodiment includes a variable distance sensor 157 as a distance sensor 159 instead of the first distance sensor 155 and the second distance sensor 156.

[0111] The variable distance sensor 157 is a distance sensor whose distance measurement range can be changed according to an instruction from the main processor 101. In the present embodiment, it is possible to switch between a medium distance sensing setting in which the medium distance is the distance measurement range (the scanning range is indicated by 157m in FIG. 14(b)) and a short distance sensing setting in which the short distance is the distance measurement range (the scanning range is indicated by 157s in FIG. 14(b)). The medium distance and the short distance are, for example, 30 cm or more and 5 m or less, and less than 30 cm, respectively, as in the first embodiment.

[0112] In each setting, the variable distance sensor 157 outputs a distance value when the distance to the object is within the set distance measurement range. On the other hand, when the distance to the object is outside the set range, an NG signal is output instead of the distance value.

[0113] FIG. 16 is a functional block diagram of functions related to the present embodiment of the smartphone 100a of the present embodiment. As shown in this figure, the smartphone 100a of the present embodiment includes an overall control unit 211, a distance measurement control unit 212, and a display control unit 218. The distance measurement control unit 212 includes a distance sensor activation unit 213, a distance measurement range switching unit 215, and a distance signal processing unit 214. In addition, a distance value DB 219 for storing the acquired distance value is provided. Since the components having the same names as those in the first embodiment have the same functions as those in the first embodiment, the description thereof is omitted here.

[0114] However, the distance sensor activation unit 213 of the present embodiment activates the variable distance sensor 157.

[0115] The ranging range switching unit 215 outputs an instruction to switch the ranging range of the variable distance sensor 157 to the variable distance sensor 157.

[0116] In the present embodiment, similar to the distance sensor 159 of the first embodiment, for example, a MEMS-based LiDAR is used. The ranging range is switched, for example, by changing the power of the laser light output from the laser light source 311. Specifically, when sensing a short distance, the emission power is suppressed compared to when sensing a medium distance. This is because when sensing a short distance, the amount of light increases and the light receiving element saturates. The emission power when sensing a medium distance and the emission power when sensing a short distance are determined in advance and stored in the storage device 110. Then, the ranging range switching unit 215 issues an output instruction to the variable distance sensor 157 (laser light source 311) to emit light with either emission power.

[0117] Note that the ranging range may be switched, for example, by changing the scanning range (157m, 1157s). Specifically, as shown in FIGS. 17(a) and 17(b), when sensing a short distance, the scanning range is widened compared to when sensing a medium distance. Specifically, the scanning angle (θm, θs) is changed. At a short distance, since the object appears large, the scanning range is widened as much as possible. As described above, the scanning range changes depending on the magnitude of the current flowing through the inner coil 332 and the outer coil 334 of the MEMS element 314. The magnitude of the current when sensing a medium distance and the magnitude of the current when sensing a short distance are determined in advance. Then, the ranging range switching unit 215 issues an instruction to the variable distance sensor 157 to flow either current.

[0118] Next, the flow of the distance measurement process by the distance measurement control unit 212 of the present embodiment will be described. FIG. 18 is the process flow of the distance measurement process of the present embodiment. This process is started by the same trigger as in the first embodiment. Also, the frequency of repetition is the same as in the first embodiment.

[0119] Hereinafter, in the present embodiment, it is assumed that the variable distance sensor 157 is initially set to the medium distance sensing setting.

[0120] The distance sensor activation unit 213 activates the variable distance sensor 157 and starts its operation (step S2101). As a result, distance measurement (distance measurement) at a medium distance is performed (step S2102).

[0121] The distance signal processing unit 214 determines whether the distance could be measured in the medium distance sensing setting (step S2103). The determination criterion is the same as in the first embodiment, that is, whether the sensor signal in a predetermined range of the distance measurement area 320 is a distance value or an NG value.

[0122] If it is determined that the measurement was successful (step S2103), the obtained distance value is saved (step S2104), and the process ends. Here, as in the first embodiment, the distance value is saved in association with the acquisition time (or the position information of the distance measurement area 320).

[0123] On the other hand, if it is determined that the measurement was not successful (S2103; No), the distance measurement range switching unit 215 switches the distance measurement range of the variable distance sensor 157. In the present embodiment, it is switched to the short distance sensing setting (step S2105). As a result, distance measurement is performed in the short distance sensing setting (step S2106).

[0124] Then, the distance signal processing unit 214 determines whether the distance could be measured in the short distance sensing setting (step S2107). If the measurement is successful, the distance measurement range is returned to the medium distance sensing setting (step S2109), and the process proceeds to step S2104.

[0125] On the other hand, if the measurement cannot be performed, the distance signal processing unit 214 performs NG processing (step S2108) as in the first embodiment, and ends the processing.

[0126] In the above embodiment, after the measurement in the short-distance sensing setting, the setting is returned to the medium-distance sensing setting, but this process may not be performed. In this case, the next measurement starts in the short-distance sensing setting. And when an NG value is obtained in step S2103 above, in step S2105, the setting is switched to the medium-distance sensing setting.

[0127] For example, when the repetition interval is short, etc., the measurement target does not change significantly. In such a case, there is a high possibility that it is the same measurement range as the previous time, and the processing can be performed efficiently.

[0128] As described above, the smartphone 100a of the present embodiment includes a distance sensor 159 that can widely measure distances around the smartphone 100a, similar to the first embodiment. Further, the distance sensor 159 can measure distances in a range, area corresponding to the shooting distance and shooting field of view of the camera included in the smartphone 100a. Therefore, the same effects as those of the first embodiment can be obtained.

[0129] Furthermore, the distance sensor 159 of the smartphone 100a of the present embodiment includes a variable distance sensor 157 capable of switching the measurement range between a first measurement range 155d and a second measurement range 156d, and a measurement range switching unit 215 that switches the measurement range of the variable distance sensor 157. And when the measurement range switching unit 215 sets the measurement range of the variable distance sensor 157 to the first measurement range 155d and no measurement value can be obtained, it switches the measurement range of the variable distance sensor 157 to the second measurement range 156d. Here, the switching between the two modes of medium distance and short distance has been described, but the measurement range may be switched in more stages.

[0130] Thus, in this embodiment, a variable distance sensor 157 capable of measuring a plurality of measurement ranges is provided. Therefore, in this embodiment, only one distance sensor is required, which can reduce costs. In addition, there are fewer restrictions on the arrangement of the distance sensor 159 within the smartphone 100a.

[0131] Also in this embodiment, similar to the first embodiment, a LiDAR using a pattern emission method may be used.

[0132] <Modification Example 7> In addition, in each of the above embodiments and modification examples, the resolution may be changed within the same measurement range. The resolution can be changed by controlling the rotation speed of the MEMS mirror 331 without changing the speed of the emission pulse. For example, FIG. 19(a) shows the state of a scan with normal resolution, and FIG. 19(b) shows the state of a high-resolution scan. As shown in these figures, the slower the rotation speed (vibration speed) of the MEMS mirror 331, the denser the scan can be performed, and the higher the resolution (higher definition) can be achieved.

[0133] For example, when the unevenness of the object is fine, or when the object is not a planar shape but is composed of thin rod-shaped parts, etc., the ranging control unit 212 is set to perform high-definition scanning and sensing, and controls the operation of the distance sensor 159.

[0134] <Modification Example 8> In addition, in each of the above embodiments and modification examples, it is assumed that the distance sensor 159 outputs an NG value when it is outside the measurement range. However, it is not limited to this. For example, when it is outside the measurement range, in order to indicate that it is outside the measurement range, the limit value of the measurement range may be shown. For each distance sensor 159, a range within which accurate distance measurement can be performed is determined in advance as the measurement range and stored in a storage device or the like.

[0135] In this case, for example, in the example of the first embodiment, in step S1103 of the distance measurement process, it is determined whether the distance value obtained by the first distance sensor 155 is within the distance measurement range of the first distance sensor 155. If it is within the distance measurement range of the first distance sensor 155, the process proceeds to step S1104. On the other hand, if it is a value outside the distance measurement range of the first distance sensor 155, the process proceeds to step S1105.

[0136] <Modification Example 9> Also, the distance sensor 159 in each of the above embodiments and modification examples may be applied to glasses (electronic glasses) having a variable focus lens. The electronic glasses 500 having a variable focus lens 530 include, for example, a liquid crystal panel 510 for performing diffraction on a part of the lens and a control device 520 for controlling the voltage applied to the liquid crystal panel 510, as described in International Publication No. 2013 / 088630 (Patent Document 3). An external view of the electronic glasses is shown in Fig. 20(a).

[0137] The variable focus lens 530 is a lens whose refractive index changes according to the applied voltage. For example, when a voltage is applied, it is set to have a refractive index for myopia (small refractive index), and when no voltage is applied, it is set to have a refractive index for hyperopia (large refractive index).

[0138] As shown in Fig. 20(b), the distance sensor 159 of the above embodiment or modification example is attached to the electronic glasses 500. The distance sensor 159 is attached, for example, to the upper center of the frame of the electronic glasses 500 above the variable focus lens 530.

[0139] In the case of the distance sensor 159 of the first embodiment, the first distance sensor 155 may be installed with its distance measurement direction facing the front direction of the electronic glasses 500, and the second distance sensor 156 for measuring a short distance may be installed with its distance measurement direction facing downward at a predetermined angle with respect to the front direction of the electronic glasses 500.

[0140] The control device 520 controls the voltage applied to the variable focus lens 530 according to the distance value from the distance sensor 159. Specifically, when receiving a distance value within a short distance range less than a predetermined threshold value, a voltage is applied to the variable focus lens 530. Thereby, the variable focus lens 530 has a refractive index for myopia.

[0141] That is, the distance sensor 159 calculates the distance to an object in the user's line-of-sight direction (the distance measurement direction of the distance sensor 159), and changes the refractive index of the variable focus lens 530 according to the distance.

[0142] In the example disclosed in Patent Document 3 above, various sensors are used to detect the inclination of the user's head. For example, when it is detected that the user has looked down to read a book, a voltage is applied to obtain a refractive index for myopia. Therefore, when looking at a nearby object without tilting the head, the refractive index for myopia is not obtained. Conversely, when going down the stairs and looking down while tilting the head, even in a situation where a refractive index for hyperopia is originally desired, it is changed to a refractive index for myopia.

[0143] According to this modification, since a voltage is applied to the variable focus lens according to the distance to an object in the user's line-of-sight direction, such a problem can be avoided, and an electronic glasses 500 with higher convenience can be provided. In addition, functions similar to those of the HMD100h in the fifth modification, such as an AR display function, may be further installed in this electronic glasses 500.

[0144] <Modification 10> In addition, in each of the above embodiments and modifications, the case where the distance measurement ranges are two types, medium distance and short distance, has been described as an example. However, it is not limited to this. There may be three or more distance measurement ranges. In this case, in the first embodiment, the number of distance sensors 159 corresponding to the number of steps of the distance measurement range is provided. Also, in the second embodiment, the distance measurement range can be changed in steps corresponding to the number of distance measurement ranges.

[0145] Also, in each of the above embodiments and modifications, the ranging range and ranging area of the distance sensor 159 are associated with the shooting distance and shooting field of view of the camera provided in the mobile terminal, but are not limited thereto. The ranging range and ranging area of the distance sensor 159 may be completely independent of the shooting distance and shooting field of view of the camera.

[0146] The present invention is not limited to the above-described embodiments and modifications, and includes various modifications. For example, the above-described embodiments and modifications have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Also, a part of the configuration of one embodiment or modification can be replaced with the configuration of another embodiment or modification. Also, the configuration of another embodiment or modification can be added to the configuration of one embodiment or modification. Furthermore, for a part of the configuration of each embodiment or modification, addition, deletion, or replacement with other configurations is possible.

[0147] Also, each of the above configurations, functions, processing units, processing means, etc. may be realized in hardware, for example, by designing a part or all of them with an integrated circuit. Also, each of the above configurations, functions, etc. may be realized in software by a processor interpreting and executing a program for realizing each function. Information such as a program, table, file, etc. for realizing each function can be placed in a memory unit, a recording device such as a hard disk, SSD (Solid State Drive), or a recording medium such as an IC card, SD card, DVD.

[0148] Also, control lines and information lines show those considered necessary for explanation, and not necessarily all control lines and information lines are shown on the product. In reality, it may be considered that almost all configurations are interconnected.

Description of Reference Numerals

[0149] 100: Smartphone, 100a: Smartphone, 100h: HMD, 101: Main processor, 102: System bus, 103: RAM, 104: ROM, 105: Flash memory, 109: Case, 110: Storage device, 120: Operating device, 121: Operation keys, 122: Touch sensor, 130: Image processing device, 131: Display, 135: First camera, 135d: Shooting distance, 135v: Shooting field of view, 136: Second camera, 136d: Shooting distance, 136v: Shooting field of view, 137: Third camera, 140: Audio processing device, 141: Speaker, 143: Microphone, 150: Sensor, 151: GPS receiver, 152: Gyro sensor, 153: Geomagnetic sensor, 154: Acceleration sensor, 155: First distance sensor, 155c: Distance measurement direction, 155d: First distance measurement range, 155v: First distance measurement area, 156: Second distance sensor, 156c: Distance measurement direction, 156d: Second distance measurement range, 156v: Second distance measurement area, 157: Variable distance sensor, 157c: Distance measurement direction, 159: Distance sensor, 160: Communication device, 161: LAN communication unit, 162: Telephone network communication unit, 163: BT communication unit, 170: Expansion interface, 180: Timer, 211: Overall control unit, 212: Distance measurement control unit, 213: Distance sensor activation unit, 214: Distance signal processing unit, 215: Distance measurement range switching unit, 218: Display control unit, 219: Distance value DB, 310: Emission unit, 311: Laser light source, 312: Collimating lens, 313: Condensing lens, 314: MEMS element, 320: Distance measurement area, 329: Object, 331: MEMS mirror, 332: Inner coil, 333: Inner torsion bar, 334: Outer coil, 335: Outer torsion bar, 340: Light receiving unit, 351: Pulse laser light, 352: Reflected light, 353: Emitted light, 354: Reflected light, 361: Diffraction grating, 363: Irradiation pattern, 500: Electronic glasses, 510: Liquid crystal panel, 520: Control device, 530: Variable focus lens

Claims

1. An electronic glasses comprising a variable focus lens whose refractive index is changed from a refractive index for farsightedness to a refractive index for nearsightedness by applying a voltage, a control device for controlling the application of the voltage to the variable focus lens, a short-distance sensor for measuring a short-distance range in which the distance from the variable focus lens is less than a predetermined threshold value, and outputting the distance to an object included in the short-distance range as a measured distance value, wherein the control device applies a voltage to the variable focus lens when the short-distance sensor outputs the measured distance value characterized by the electronic glasses.

2. The electronic glasses according to claim 1, wherein the short-distance sensor is installed such that its distance measurement direction is downward at a predetermined angle with respect to the front direction of the electronic glasses, and the control device applies a voltage to the variable focus lens according to the measured distance value when the short-distance sensor outputs the measured distance value characterized by the electronic glasses.

3. The electronic glasses according to claim 2, wherein the variable focus lens is set such that its refractive index decreases when a voltage is applied, and its refractive index increases when no voltage is applied characterized by the electronic glasses.

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