Video image display device and control method

Abstract

To suppress the decrease in a sense of immersion and a sense of reality due to a movement of a part of a mechanism for showing a 3D video image to a user by a motor.SOLUTION: A video image display device that can be used by being mounted on a head part of a user includes: a display part; an eyepiece optical system that guides a video image displayed on the display part to a user; a motor that generates a driving force that moves at least one of the display part and the eyepiece optical system in a direction parallel to an optical axis of the eyepiece optical system; an output part that outputs an audio data related to the video image displayed on the display part; and control means of controlling a drive mode of the motor according to an output destination of the audio data by the output part.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an image display device that can be worn on a user's head. [Background technology]

[0002] Image display devices that can be worn on a user's head, such as head-mounted displays (HMDs), provide three-dimensional (3D) images to the user by displaying images rendered with binocular parallax on left-eye and right-eye display units. Such 3D imaging techniques using binocular parallax can impose a heavy burden on the user due to a convergence accommodation conflict caused by a mismatch between the convergence distance and accommodation distance between the two eyes. The convergence accommodation conflict is commonly referred to as a vergence accommodation conflict (VAC). An effective solution to this problem is to vary the accommodation distance (or focal length) of the display optical system, including the display unit. Patent Document 1 proposes a technology in which either the display or the eyepiece optical system is moved along the optical axis of the eyepiece optical system by the driving force of a motor.

[0003] Furthermore, the interpupillary distance between the left and right eyes varies from person to person, and if the distance between the left and right lenses does not correspond to the interpupillary distance, it can be difficult to see the displayed image in 3D. The interpupillary distance is commonly called the interpupilary distance (IPD). To solve this problem, it is effective to make the distance between the left and right of the display optical system, including the display unit, variable.

[0004] As described above, in order for a user to comfortably view 3D images in an image display device that can be worn on the user's head, it is effective to use a motor to move part of the mechanism that shows the 3D images to the user.

[0005] On the other hand, video display devices that can be worn on the user's head are expected to provide the user with a sense of immersion in a virtual reality space and a powerful sense of presence, but if sounds and vibrations unrelated to the video content the user is viewing are transmitted to the user, there is a risk that this sense of immersion and presence may be impaired. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 9-68670 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the technology described in the cited document 1 does not take into consideration the influence on the user of the driving noise and vibration of the motor when moving either the display or the eyepiece optical system.

[0008] Therefore, an object of the present invention is to provide an image display device that can suppress the reduction in the sense of immersion and realism caused by using a motor to move part of the mechanism for showing 3D images to the user. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the image display device of the present invention is an image display device that can be worn on a user's head and used, and is characterized by having a display unit, an eyepiece optical system that guides the image displayed on the display unit to the user, a motor that generates a driving force that moves at least one of the display unit and the eyepiece optical system in a direction parallel to the optical axis of the eyepiece optical system, an output unit that outputs audio data related to the image to be displayed on the display unit, and control means that controls the driving mode of the motor depending on the output destination of the audio data by the output unit. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an image display device that can suppress a decrease in the sense of immersion and realism caused by using a motor to move part of a mechanism for showing 3D images to a user. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view of an image display device that can be worn on a user's head and used according to an embodiment of the present invention; [Figure 2] 1 is a schematic diagram illustrating the configuration of a display and an eyepiece optical system of an image display device according to an embodiment of the present invention. [Figure 3] FIG. 3 is a schematic diagram illustrating the configuration of a mechanism (variable focus mechanism) included in the optical unit 7 that changes the distance A shown in FIG. [Figure 4] A schematic diagram of the main body 1 as seen from the user's side [Figure 5] FIG. 1 is a block diagram showing components related to motor control of a video display device according to a first embodiment; [Figure 6] FIG. 10 is a diagram illustrating the relationship between the settings of the audio output unit 21 and the drive modes of the motors 4 and 4′ in the first embodiment. [Figure 7] FIG. 10 is a block diagram showing components related to motor control of a video display device according to a second embodiment. [Figure 8] FIG. 10 is a diagram illustrating the relationship between the settings of the audio output unit 21 and the drive modes of the motors 4 and 4′ in the second embodiment. [Figure 9] FIG. 10 is a diagram illustrating the relationship between the settings of the audio output unit 21 and the drive modes of the motors 4 and 4′ in the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0013] FIG. 1 is a perspective view of an image display device, such as a head-mounted display (HMD), according to an embodiment of the present invention, that can be worn on a user's head. The image display device according to the embodiment of the present invention is composed of a main body unit 1 and a head-mounted unit 2. The main body unit 1 includes a display unit for displaying images and eyepiece optical systems for the left and right eyes, respectively, that realize a wide viewing angle for guiding the images displayed on the display units to the user. The main body unit 1 also includes various circuits for controlling the entire image display device. The head-mounted unit 2 includes a band for wearing on the user's head and a built-in speaker 24 (described below) that is positioned near the user's ear when the head-mounted unit 2 is worn on the user's head. The output method of the built-in speaker 24 is not particularly limited and may be air conduction or bone conduction. In FIG. 1, the Z direction corresponds to the direction in which the user views the display, the X direction corresponds to the left-right direction of the image viewed by the user (the left-right direction of the display), and the Y direction corresponds to the up-down direction of the image viewed by the user (the up-down direction of the display).

[0014] Fig. 2 is a schematic diagram of the display and eyepiece optical system of an image display device according to an embodiment of the present invention. As shown in Fig. 2, the main body 1 has an optical unit 7a equipped with a display 5a and an eyepiece optical system 6a for the left eye 3a, and an optical unit 7b equipped with a display 5b and an eyepiece optical system 6b for the right eye 3b. In Fig. 2, the optical units 7a and 7b have the same configuration, so in the following description, they will be referred to as the display 5, the eyepiece optical system 6, and the optical unit 7. For example, the display 5 is a liquid crystal panel or an organic EL panel, and the eyepiece optical system 6 is a lens.

[0015] Distance A in FIG. 2 indicates the distance between the display 5 and the eyepiece optical system 6. By changing distance A, the distance to the image in the virtual space that the user is viewing, i.e., the accommodation distance (or focal length), can be arbitrarily determined. Note that the method for changing distance A described below is to move the eyepiece optical system 6 in a direction parallel to the optical axis of the eyepiece optical system 6 using a motor, but it is also possible to move the display 5 in a direction parallel to the optical axis of the eyepiece optical system 6 using a motor. Alternatively, it is also possible to move each of the display 5 and the eyepiece optical system 6 in a direction parallel to the optical axis of the eyepiece optical system 6 using a motor.

[0016] Distance B in Figure 2 indicates the distance between the optical centers of the optical units 7. The smaller the difference between distance B and the user's interpupillary distance (the distance between the left eye 3a and the right eye 3b), the more accurately a stereoscopic image can be viewed. A method for changing distance B, which will be described later, is to use a motor to move each of optical units 7a and 7b in a direction perpendicular to the optical axis of the eyepiece optical system 6. However, it is also possible to use a motor to move only one of optical units 7a and 7b in a direction perpendicular to the optical axis of the eyepiece optical system 6.

[0017] FIG. 3 shows a YZ cross-sectional view, viewed from the X direction, of a schematic configuration diagram of the mechanism (variable focus mechanism) included in the optical unit 7 that changes the distance A shown in FIG. 2. The variable focus mechanism includes a motor 4 that generates a driving force to move the eyepiece optical system 6, a display 5, the eyepiece optical system 6, and a transmission member 8 that transmits the driving force of the motor 4 to the eyepiece optical system 6. While FIG. 3 depicts the eyepiece optical system 6 as a single lens, it may be a lens group consisting of multiple lenses, as long as at least one lens is moved by the motor 4 in a direction parallel to the optical axis of the eyepiece optical system 6 (the Sz direction). The eyepiece optical system 6 is connected to the motor 4 via the transmission member 8, and the driving force of the motor 4 is transmitted to it. However, the connection of the eyepiece optical system 6 to the motor 4 via the transmission member 8 can be performed using a known method, and detailed description thereof will be omitted. For example, a holding member that holds the eyepiece optical system 6 may be connected to a movable member (transmission member 8) engaged with the lead screw of the motor 4. A guide mechanism for moving the eyepiece optical system 6 in a direction parallel to the optical axis of the eyepiece optical system 6 may be provided. However, a detailed description thereof will be omitted since a well-known configuration may be used. For example, a guide bar extending parallel to the optical axis of the eyepiece optical system 6 may be inserted into a hole formed in a holder for holding the eyepiece optical system 6, and the eyepiece optical system 6 may be moved along the guide bar by the driving force of a motor. Note that while FIG. 3 illustrates a motor 4 having a lead screw, other driving methods for the motor 4 may be used. For example, a motor that uses a piezoelectric element to vibrate a vibrator to generate a driving force in the Sz direction or a motor that uses a coil and a magnet to generate a driving force in the Sz direction may be used. Also, in FIG. 3, the motor 4 is positioned below the eyepiece optical system 6 in the Y direction in the optical unit 7. However, the position of the motor 4 is not limited to the position illustrated in FIG. 3. The motor 4 may be positioned above the eyepiece optical system 6 in the Y direction as long as it moves integrally with the optical unit 7.

[0018] It is preferable that the relative distance between the display 5 and the eyepiece optical system 6 be changed in accordance with the distance in virtual space (virtual object distance) of an object that the user focuses on in the video displayed on the display 5. Therefore, in this embodiment, a process of repeatedly changing the relative distance between the display 5 and the eyepiece optical system 6 is performed even while the video content is being viewed, in accordance with instructions from the main body system control unit 20, which will be described later. The amount of change in the relative distance between the display 5 and the eyepiece optical system 6 can be calculated using a known method, and therefore a detailed description thereof will be omitted.

[0019] FIG. 4 shows a schematic diagram of the main body 1 as seen from the user's side, illustrating a mechanism (pupillary distance adjustment mechanism) for moving the optical units 7a and 7b relative to the main body 1 in a direction perpendicular to the optical axis of the eyepiece optical system 6 (the Sx direction). The optical unit 7a is the optical unit for the left eye, and the optical unit 7b is the optical unit for the right eye. The pupillary distance adjustment mechanism includes a motor 4' that generates a driving force to move the optical unit 7, the optical unit 7, and a base 9 on which the motor 4' is mounted. The motor 4' is connected to the optical unit 7 and the base 9, and the generated driving force moves the optical unit 7 in the Sx direction relative to the base 9. Note that while the configuration has been described in which the position of the base 9 relative to the main body 1 does not change even when the driving force of the motor 4' is generated, a configuration in which the position of the base 9 relative to the main body 1 changes when the driving force of the motor 4' is generated may also be adopted, as long as the distance B shown in FIG. 2 can be adjusted. Furthermore, the configuration for connecting the motor 4' to the optical unit 7 and the base 9 and the configuration for transmitting the driving force of the motor 4' to the optical unit 7 may be well-known configurations, similar to the variable focus mechanism described above, and therefore detailed description thereof will be omitted. A guide mechanism or the like for moving the optical unit 7 in the Sx direction may be provided, but a well-known configuration may be used, similar to the variable focus mechanism described above, and therefore detailed description thereof will be omitted. The drive method for the motor 4' may also be another well-known method, similar to the drive method for the motor 4. The position at which the motor 4' is located is not limited to a position below the eyepiece optical system 6, and the motor 4' may also be located above the eyepiece optical system 6. The following description will be given assuming that the motors 4 and 4' are driven by the same drive method, but different drive methods may also be used.

[0020] The relative distance between the optical units 7a and 7b in a direction perpendicular to the optical axis of the eyepiece optical system 6 preferably corresponds to the distance between the user's left and right eyes. Therefore, the interpupillary distance adjustment process, which changes the relative distance between the optical units 7a and 7b in a direction perpendicular to the optical axis of the eyepiece optical system 6, only needs to be performed once after the user puts on the image display device. However, if the user's posture changes significantly while wearing the image display device, the optical units 7a and 7b may move relative to each other. Therefore, in this embodiment, the interpupillary distance adjustment process is repeatedly performed to change the relative distance between the optical units 7a and 7b in accordance with instructions from the main body system control unit 20, even while the user is viewing video content. Since the amount of change in the relative distance between the optical units 7a and 7b can be calculated using a known method, detailed description thereof will be omitted. A known gaze detection sensor (not shown) may be included in the configuration to detect the positions of the user's left and right eyes.

[0021] Next, we will explain the relationship between the noise level and the speed at which the driven object is moved by the motors 4 and 4'. Generally, when a motor's driving force drives a driven object linearly, the noise level tends to increase as the driven object moves faster. For example, let's say that the motors 4 and 4' are stepping motors that convert rotary drive into linear drive using a lead screw. In this case, if the motor rotation speed is increased to increase the moving speed of the driven object, the noise generated by the motor itself will increase, as will the sound emitted by the linear drive converter. Even if the motor is not a stepping motor, but a voice coil motor using a coil and magnet, or an ultrasonic motor using a vibrator, the tendency for noise to increase as the moving speed of the driven object increases is the same.

[0022] Next, we will explain the relationship between the acceleration of the driven body caused by the motors 4 and 4' and the vibration level. Generally, when a driven body is driven linearly by the driving force of a motor, the vibration level tends to increase as the acceleration increases. The guide mechanism that guides the linear movement of the driven body supports the weight of the moving driven body, so the load on the guide fluctuates depending on the acceleration and deceleration of the non-driven body. The greater the acceleration, the greater the load, and when the load increases, large vibrations are likely to occur. For example, when a linear drive is reversed due to sudden deceleration and acceleration, the driven body tilts during the reversal, placing a large load on the guide mechanism and easily generating vibrations. The generated vibrations are propagated throughout the device via the components surrounding the guide mechanism. Such vibrations can occur not only in the guide mechanism but also in the transmission members that transmit the driving force of the motor to the driven body.

[0023] (First embodiment) FIG. 5 is a block diagram showing components related to motor control of the video display device according to the first embodiment of the present invention. The main system control unit 20 includes a processor, such as a CPU or MPU, and controls each block of the video display device by reading and executing programs stored in a ROM. The audio output unit 21 outputs audio data (provided as content information of the video content) related to the video displayed on the display 5 to the built-in speaker 24 of the video display device or to an external audio device 25 independent of the video display device. The external audio device 25 is, for example, earphones or headphones. When outputting audio data to the external audio device 25, the audio output unit 21 may use known wired or wireless communication. The audio output unit 25 may include at least one of a connector to which a cable for wired communication can be connected and a wireless communication module for wireless communication. The motor control unit 22 outputs control command values ​​to the motors 4, 4′ in accordance with instructions from the main system control unit 20. The volume setting unit 23 receives input from a volume setting unit 27, such as a volume button (not shown) of the video display device or a setting value on a volume input screen displayed on the display 5, and changes the volume value when playing audio data. Note that other methods for setting the volume may be used, and the volume setting means 27 may communicate with an operating device to acquire the results of operation of a button, lever, or the like provided on the operating device dedicated to the video display device. Alternatively, the volume setting means 27 may communicate with the external information terminal to acquire the volume value set on the external information terminal such as a smartphone or tablet terminal.

[0024] 5, the image displayed on the display 5 is controlled by the main system control unit 20. There are no particular limitations on the method for displaying the image on the display 5, and any known method may be used.

[0025] 6 is a diagram illustrating the relationship between the settings of the audio output unit 21 and the drive modes of the motors 4, 4′ in this embodiment. The settings of the audio output unit 21 include a setting (first setting) for outputting audio data to the built-in speaker 24 and a setting (second setting) for outputting audio data to an external audio device.

[0026] The drive modes include a normal drive mode (first drive mode) and a drive noise reduction mode (second drive mode). The drive noise reduction mode is a mode that can suppress drive noise associated with motor drive more than the normal drive mode and has a lower upper speed limit than the normal drive mode. When the setting is to output audio data to an external audio device, it is assumed that the user will watch video content with their ears covered by earphones or headphones. Therefore, sounds such as external noise other than audio data are less likely to reach the user's ears, and the drive noise of the motors 4, 4′ is less likely to interfere with the user's sense of immersion or realism. On the other hand, when the setting is to output audio data to the built-in speaker 24, it is assumed that the user will watch video content with their ears open to listen to sound from the built-in speaker 24 provided in the head-mounted unit 2. Therefore, sounds such as external noise other than audio data are more likely to reach the user's ears, and the drive noise of the motors 4, 4′ may interfere with the user's sense of immersion or realism.

[0027] Therefore, as shown in FIG. 6 , when audio data is set to be output to an external audio device, the motors 4, 4′ are driven in the normal drive mode because there is little need to suppress the drive noise of the motors 4, 4′. When audio data is set to be output to the built-in speaker 24, the motors 4, 4′ are driven in either the normal drive mode or the drive noise reduction mode because the impact of the motor drive noise varies depending on the playback volume of the video content being viewed. In this case, the motor control unit 22 may acquire information regarding the volume value from the volume setting unit 23, and set the motors to the drive noise reduction mode if the volume value indicated by the acquired information is equal to or less than a predetermined value, or set the motors to the normal drive mode if the volume value is greater than the predetermined value. Alternatively, the motor control unit 22 may acquire audio data from the audio output unit 21, and set the motors to the drive noise reduction mode if the volume indicated by the acquired audio data is equal to or less than a predetermined value, or set the motors to the normal drive mode if the volume indicated by the audio data is greater than the predetermined value. Alternatively, the drive mode may be set based on a combination of the volume value and the audio data. Alternatively, the drive mode may be set based on the user's intention, such as a user operation.

[0028] Alternatively, the user may be allowed to select whether or not the drive mode is to be set automatically in accordance with the setting of the audio output unit 21, and the drive mode may be set as described above only when the user selects automatic setting. In this configuration, when the user does not select automatic setting, the drive noise reduction mode may be set in accordance with the user's intention, such as a user operation, even when the setting is to output audio data to an external audio device.

[0029] When the drive noise reduction mode is set, the upper speed limit for the drive noise reduction mode is set to a value lower than the upper speed limit for the normal drive mode. The set value can be any value, such as 1 / 2 or 1 / 4 of the normal mode value in the drive noise reduction mode, or a value according to user operation. Alternatively, the upper speed limit can be set according to the volume of the audio data of the video content analyzed before playback, or the most recent volume can be obtained in real time during playback of the video content and the upper speed limit can be changed continuously.

[0030] Alternatively, the main body system control unit 20 may acquire various information to determine the drive mode of the motors 4, 4', and then transmit instructions to the motor control unit 22 according to the determined drive mode.

[0031] As described above, in this embodiment, the motor can be driven in a drive mode that suppresses the motor drive noise depending on the situation, thereby preventing a decrease in the sense of immersion and realism caused by using the motor to move part of the mechanism that shows the 3D image to the user.

[0032] In the above embodiment, when the output destination of the audio data is the built-in speaker, either the normal drive mode or the drive noise reduction mode is automatically set, and when the output destination of the audio data is an external audio device, the normal drive mode is set. That is, the drive mode of the motor that can be automatically set is made different depending on the output destination of the audio data. However, the drive mode of the motor that can be automatically set may also be made different depending on the output destination of the audio data. That is, when the output destination of the audio data is the built-in speaker, the drive noise reduction mode may be automatically set, and when the output destination of the audio data is an external audio device, the normal drive mode may be automatically set.

[0033] (Second embodiment) Next, a second embodiment of the present invention will be described, but detailed descriptions of the same parts as in the first embodiment will be omitted.

[0034] 7 is a block diagram showing components involved in motor control of the image display device according to this embodiment. Unlike the first embodiment, this embodiment sets the drive mode of motors 4, 4' according to the attitude of the image display device. An attitude detection unit 27 measures the amount of change in attitude of the image display device using an attitude sensor 28, which is provided on the main body 1 or the head-mounted unit 2 and has at least one of a gyro sensor and an acceleration sensor. A motor control unit 22 sets the drive mode of motors 4, 4' according to information indicating the detection result output from the attitude detection unit 27, and outputs a control command value.

[0035] 8 is a diagram illustrating the relationship between the settings of the audio output unit 21 and the drive modes of the motors 4, 4' in this embodiment. In this embodiment, as in the first embodiment, the settings of the audio output unit 21 include a setting (first setting) for outputting audio data to the built-in speaker 24 and a setting (second setting) for outputting audio data to an external audio device. In the first embodiment, when the setting is to output audio data to an external audio device, the drive sound of the motors 4, 4' is set to the normal drive mode because it is unlikely to interfere with the user's sense of immersion or realism.

[0036] However, even when the setting is such that audio data is output to an external audio device, mechanical vibrations caused by motor drive propagate, which may reduce the user's sense of immersion and realism.

[0037] Therefore, in this embodiment, a vibration reduction mode (third drive mode) can be set as a drive mode in addition to the normal drive mode and drive noise reduction mode described in the first embodiment. Vibration reduction mode 14 is a mode that can suppress mechanical vibrations caused by motor drive more than the normal drive mode, and is a mode in which the upper acceleration limit value is lower than that of the normal drive mode.

[0038] As shown in Figure 8, by making it possible to set not only the normal drive mode but also the vibration reduction mode when the setting is to output audio data to an external audio device, it is possible to prevent a decrease in the user's sense of immersion and realism when the setting is to output audio data to an external audio device.

[0039] In this embodiment, when audio data is set to be output to an external audio device, whether to set the normal drive mode or the vibration reduction mode is determined according to the attitude of the video display device. When the video display device is stationary, the user is likely to feel mechanical vibrations caused by motor drive, whereas when the video display device is moving, the user is unlikely to feel mechanical vibrations caused by motor drive. Therefore, the vibration reduction mode is set when the amount of change in the attitude of the detection signal output from the attitude sensor 28 is equal to or greater than a threshold value, or when the frequency of change in the amount of change in the attitude of the detection signal output from the attitude sensor 28 within a predetermined period is equal to or greater than a predetermined value. By setting the drive mode in this manner, it is possible to prevent a decrease in the user's sense of immersion and realism in a state where the user is likely to feel mechanical vibrations.

[0040] As in the first embodiment, the drive mode may be set according to the user's intention, such as a user operation. In this case, the vibration reduction mode may be set even when the setting is such that audio data is output to the built-in speaker 24.

[0041] When vibration reduction mode 14 is selected, the upper acceleration limit for vibration reduction mode is set to a value lower than the upper acceleration limit for normal mode. The set value may be any value, such as 1 / 2 or 1 / 4 of the value for normal mode in vibration reduction mode, or may be a value according to user operation. Alternatively, the upper acceleration limit may be set according to information indicating the posture detection results obtained by analyzing the output signal of posture sensor 28 during viewing, or information indicating the posture detection results in real time may be obtained during playback of video content and the upper acceleration limit may be changed continuously.

[0042] (Third embodiment) Next, a third embodiment of the present invention will be described. Detailed descriptions of the same parts as those of the first or second embodiment will be omitted. 9 is a diagram illustrating the relationship between the settings of the audio output unit 21 and the drive modes of the motors 4, 4' in this embodiment. In this embodiment, a vibration and drive sound reduction mode (fourth drive mode) can be set as the drive mode instead of the drive sound reduction mode and vibration reduction mode described in the first and second embodiments.

[0043] The vibration and drive noise reduction mode is a mode in which the upper speed limit and acceleration limit are lower than those in the normal drive mode in order to suppress mechanical vibration and drive noise caused by motor drive. In the vibration and drive noise reduction mode, the upper speed limit and acceleration limit can be set in the same manner as described in the first and second embodiments.

[0044] 9, the vibration and drive noise reduction mode can be set regardless of the setting of the audio output unit 21, but the influence of the drive noise differs depending on the setting of the audio output unit 21. Therefore, when the vibration and drive noise reduction mode is set when the setting is to output audio data to the built-in speaker 24, the upper speed limit value may be lower than when the vibration and drive noise reduction mode is set when the setting is to output audio data to an external audio device.

[0045] Furthermore, the conditions for setting the vibration / driving noise reduction mode may be the same as both the conditions for setting the drive noise reduction mode in the first embodiment and the conditions for setting the vibration reduction mode in the second embodiment. In this case, the vibration / driving noise reduction mode may be set when either the conditions for setting the drive noise reduction mode or the conditions for setting the vibration reduction mode are met, or the vibration / driving noise reduction mode may be set when both conditions are met.

[0046] Furthermore, the drive mode may be set in accordance with the user's intention, such as a user operation, as in the first and second embodiments.

[0047] As described above, in this embodiment, the motor can be driven in a drive mode that suppresses the motor's drive noise and mechanical vibration depending on the situation, thereby preventing a decrease in the sense of immersion and realism caused by using the motor to move part of the mechanism that shows the 3D image to the user.

[0048] In the above three embodiments, the setting of the drive modes of the motors 4 and 4' has been described, but the relative distance between the optical units 7a and 7b may not be changed while video content is being viewed. In other words, the motor 4' may not be driven while video content is being viewed, and the above-described drive mode setting may be applied only to the motor 4.

[0049] In the above three embodiments, examples have been described in which at least one of the display 5 and the eyepiece optical system 6 and at least one of the optical units 7a and 7b are moved by a motor as examples of moving part of a mechanism for showing a 3D image to a user. However, only at least one of the display 5 and the eyepiece optical system 6 may be moved by a motor, or only at least one of the optical units 7a and 7b may be moved by a motor. Alternatively, part of a mechanism other than those described above may be moved by a motor.

[0050] Furthermore, in the above three embodiments, the head mounted unit 2 is provided with the built-in speaker 24, but the main body 1 may be provided with the built-in speaker 24 instead.

[0051] Moreover, the various circuits that control the entire image display device may be included in either the main body 1 or the head-mounted unit 2.

[0052] In the above three embodiments, the terms normal drive mode and reduced mode are used to describe the relative levels of the upper speed limit and the upper acceleration limit, but either may be the normal drive mode. For example, a drive mode in which the upper speed limit and the upper acceleration limit are relatively low may be referred to as the normal drive mode, and a drive mode in which the upper speed limit and the upper acceleration limit are relatively higher than those in the normal drive mode may be referred to as the high drive mode.

[0053] (Other embodiments) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0054] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention.

[0055] The disclosure of this embodiment includes the following configuration. (Configuration 1) An image display device that can be worn on a user's head and used, A display unit; an eyepiece optical system that guides the image displayed on the display unit to a user; a motor that generates a driving force to move at least one of the display unit and the eyepiece optical system in a direction parallel to the optical axis of the eyepiece optical system; an output unit that outputs audio data related to the video to be displayed on the display unit; and a control means for controlling a drive mode of the motor in accordance with an output destination of the audio data from the output section. (Configuration 2) An image display device that can be worn on a user's head and used, a left-eye optical unit and a right-eye optical unit, each having a display unit and an eyepiece optical system that guides an image displayed on the display unit to a user; a motor that generates a driving force to move at least one of the left-eye optical unit and the right-eye optical unit in a direction perpendicular to the optical axis of the eyepiece optical system; an output unit that outputs audio data related to the video to be displayed on the display unit; and a control means for controlling a drive mode of the motor in accordance with an output destination of the audio data from the output section. (Configuration 3) The video display device according to configuration 1 or 2, wherein the control means automatically sets different drive modes for the motor depending on whether the audio data is output to a built-in speaker or an external audio device. (Configuration 4) The video display device according to configuration 3, wherein the control means sets a drive mode in which the upper speed limit value is lower when the output destination of the audio data is an internal speaker than when the output destination of the audio data is an external audio device. (Configuration 5) The video display device according to configuration 1 or 2, wherein the control means automatically sets different drive modes for the motor depending on whether the audio data is output to a built-in speaker or an external audio device. (Configuration 6) The video display device according to configuration 5, wherein the control means is capable of setting a drive mode in which the upper speed limit value of the motor is lower when the audio data is output to a built-in speaker than when the audio data is output to an external audio device. (Configuration 7) 7. The video display device according to configuration 5 or 6, wherein the control means is capable of setting two drive modes having different upper speed limits for the motor when the audio data is output to a built-in speaker. (Configuration 8) The video display device according to any one of configurations 5 to 7, characterized in that when the output destination of the audio data is a built-in speaker, the control means sets the drive mode of the motor according to the volume value when the audio data is played back. (Configuration 9) The video display device according to any one of configurations 5 to 7, characterized in that the control means sets the drive mode of the motor according to the volume indicated by the audio data when the output destination of the audio data is a built-in speaker. (Configuration 10) an attitude detection unit that detects the attitude of the image display device; The video display device according to any one of configurations 1 to 9, characterized in that the control means, when the output destination of the audio data is an external audio device, changes the drive mode of the motor that is automatically set in accordance with the detection result of the posture detection unit. (Configuration 11) The video display device according to any one of configurations 1 to 10, characterized in that the control means is capable of setting two drive modes with different upper acceleration limits for the motor when the output destination of the audio data is an external audio device. [Explanation of symbols]

[0056] 1 Main body 2 Head-mounted unit 3 eyes 4 motors 5. Display 6 Eyepiece optical system 7 Optical Unit 20 Main system control unit 21 Audio output section 22 Motor control unit 23 Volume setting section 24 Built-in speaker 25 External audio equipment 26 Volume setting section 27 Attitude detection unit 28 Attitude Sensor

Claims

1. An image display device that can be worn on a user's head and used, A display unit; an eyepiece optical system that guides the image displayed on the display unit to a user; a motor that generates a driving force to move at least one of the display unit and the eyepiece optical system in a direction parallel to the optical axis of the eyepiece optical system; an output unit that outputs audio data related to the video to be displayed on the display unit; and a control means for controlling a drive mode of the motor in accordance with an output destination of the audio data from the output section.

2. An image display device that can be worn on a user's head and used, a left-eye optical unit and a right-eye optical unit, each having a display unit and an eyepiece optical system that guides an image displayed on the display unit to a user; a motor that generates a driving force to move at least one of the left-eye optical unit and the right-eye optical unit in a direction perpendicular to the optical axis of the eyepiece optical system; an output unit that outputs audio data related to the video to be displayed on the display unit; and a control means for controlling a drive mode of the motor in accordance with an output destination of the audio data from the output section.

3. The video display device according to claim 1 or 2, characterized in that the control means automatically sets different drive modes for the motor depending on whether the audio data is output to a built-in speaker or an external audio device.

4. 4. The video display device according to claim 3, wherein the control means sets a drive mode in which the upper speed limit value is lower when the audio data is output to an internal speaker than when the audio data is output to an external audio device.

5. The video display device according to claim 1 or 2, characterized in that the control means automatically sets different drive modes for the motor depending on whether the audio data is output to a built-in speaker or an external audio device.

6. The video display device according to claim 5, characterized in that the control means is capable of setting a drive mode in which the upper speed limit value of the motor is lower when the audio data is output to a built-in speaker than when the audio data is output to an external audio device.

7. 6. The video display device according to claim 5, wherein the control means, when the audio data is output to a built-in speaker, makes it possible to set two drive modes having different upper speed limits for the motor.

8. 8. The video display device according to claim 7, wherein the control means sets a drive mode of the motor in accordance with a volume value when the audio data is to be output to a built-in speaker.

9. 8. The video display device according to claim 7, wherein the control means sets a drive mode of the motor in accordance with a volume indicated by the audio data when the audio data is output to a built-in speaker.

10. an attitude detection unit that detects the attitude of the image display device; 6. The video display device according to claim 5, wherein the control means changes the drive mode of the motor that is automatically set in accordance with the detection result of the attitude detection section when the audio data is output to an external audio device.

11. 11. The video display device according to claim 10, wherein the control means, when the audio data is output to an external audio device, makes it possible to set two drive modes having different upper acceleration limits for the motor.

12. a display unit, an eyepiece optical system that guides the image displayed on the display unit to a user, a motor that generates a driving force that moves at least one of the display unit and the eyepiece optical system in a direction parallel to the optical axis of the eyepiece optical system, and an output unit that outputs audio data of the video content to be displayed on the display unit. A control method for a video display device that can be worn on a user's head and used, comprising: A control method for a video display device, comprising controlling a drive mode of the motor in accordance with an output destination of the audio data from the output unit.

13. a left-eye optical unit and a right-eye optical unit each having a display unit and an eyepiece optical system that guides the image displayed on the display unit to a user; a motor that generates a driving force to move at least one of the left-eye optical unit and the right-eye optical unit in a direction perpendicular to the optical axis of the eyepiece optical system; and an output unit that outputs audio data of the video content to be displayed on the display unit. A control method for a video display device that can be worn on a user's head and used, comprising: A control method for a video display device, comprising controlling a drive mode of the motor in accordance with an output destination of the audio data from the output unit.

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