Video display device, driving method of video display device and program thereof

Abstract

To provide a video display device that can alleviate accumulation of sickness or fatigue in a case where prolonged period video viewing is continued so as to mitigate a burden on a user while providing the user with a video having a three dimensional feel.SOLUTION: A video display device according to the present application solving the problem to be solved comprises: a first and a second video display units that respectively display a first and a second videos for a right eye and a left eye of a user; first and second display optical elements that respectively correspond to the first and the second video display units; and an actuator that changes a position of the display optical element. The video display device is characterized by changing the position of at least one of the first and second display optical elements by driving the actuator on the basis of a detection result of a physiological state or a psychological state of the user who is using the video display device.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a technique for adjusting visibility in a video display device.

Background Art

[0002] There are video display devices such as head-mounted displays that are worn on the user's head and used, and video display devices that are worn and used like glasses by the user. A display unit is arranged near the user's eyes, and parallax video display processing is performed for each of the user's left and right eyes. By the user visually recognizing the displayed parallax video, a three-dimensional effect for the object displayed in the parallax video can be obtained.

[0003] In this video display device, the user's line of sight is adjusted to the position of the stereoscopic video generated by the video displayed for each of the left and right eyes, but the focal position is adjusted to each of the left and right images on the display screen. This results in an unnatural state that cannot occur when visually recognizing a real object.

[0004] For example, when the user views an image of an object displayed as a parallax video, the user's convergence angle changes according to the position of the displayed object. At this time, based on the experience in the real space, the focal length of the lens changes according to the magnitude of the convergence angle. In this case, there is a possibility that the focal length of the lens and the visibility of the video display device do not match, the displayed parallax video is out of focus, and it may be difficult to view clearly, etc., and good visibility may not be ensured. Therefore, in the visibility adjustment of the video display device, it is desirable to change the visibility according to the depth information in the parallax video that determines the user's convergence angle by a method such as driving a lens in the device.

[0005] In Patent Document 1, by performing visibility adjustment for depth information according to the position of the user's fixation point when viewing a video, corresponding to individual differences and the usage state of the video display device, it is possible to reduce the discomfort during stereoscopic viewing.

Prior Art Documents

Patent Documents

[0006] Patent Document 1 Japanese Unexamined Patent Application Publication No. 2023-32278 Summary of the Invention Problems to be Solved by the Invention

[0007] However, even if the discomfort during stereoscopic vision is reduced by adjusting the visibility, when continuous video viewing is carried out for a long time, nausea and fatigue will accumulate due to the accumulation of changes in the user's physical condition and deviations in visibility adjustment. In particular, when a video in which an object displayed in a parallax video is displayed at a position in front of the user is viewed for a long time, it is known that a lot of nausea and fatigue occur. Users of video display devices have many opportunities for long-term viewing, such as games and live shows, and it is not pleasant for users to feel nausea and fatigue either.

[0008] Therefore, an object of the present invention is to provide a video display device that can reduce the burden on a user during long-term video viewing while providing a stereoscopic video with parallax to the user. Means for Solving the Problems

[0009] The video display device that achieves the above object includes first and second video display units that respectively display first and second videos for the user's right eye and left eye, first and second display optical elements respectively corresponding to the first and second video display units, and an actuator that changes the position of the display optical element, and is a video display device comprising: changing the position of at least one of the first and second display optical elements by driving the actuator based on the detection result of the physiological state or psychological state of the user during use of the video display device. Effects of the Invention

[0010] According to the video display device of the present invention, according to the state of intoxication or fatigue of the user during long-term video viewing, the burden on the user when displaying a stereoscopic video due to parallax can be reduced.

Brief Description of the Drawings

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Modes for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the embodiments, as an example of a video display device capable of performing stereoscopic display through a plurality of video display units each displaying a pair of videos having parallax via a plurality of display optical elements, a head-mounted display will be described.

[0013] The video display device of the present invention includes first and second video display units that respectively display first and second videos for the user's right eye and left eye. Further, it includes first and second display optical elements respectively corresponding to the first and second video display units, and an actuator that changes the position of the display optical elements. Then, by driving the actuator based on the detection result of the physiological or psychological state of the user during use of the video display device, at least one of the positions of the first and second display optical elements is changed.

[0014] Also, the following embodiments are typical configuration examples and are not limited to the description. Without departing from the spirit of the present invention, a video display device, a control method for the video display device, and a program thereof can be configured in a desired combination.

[0015] <First Embodiment> FIG. 1 is a diagram showing a schematic configuration of a video display device 100 according to the first embodiment of the present invention. The video display device 100 includes a video acquisition unit 101 and a display processing unit 102. The video acquisition unit 100 acquires a display video to be displayed on the video display unit 103 through an external device (not shown), a network, or the like. The display processing unit 102 performs processing such as adjusting the display magnification on the acquired video. The processed video is sent to and displayed on the video display units 103a and 103b. For example, the video is divided and displayed on each of the video display units 103a and 103b, but the configuration is not limited to this, and one screen may be divided into two regions, and the videos corresponding to the divided video display units may be displayed.

[0016] The image display device 100 includes first and second display optical elements corresponding to the left eye 201a and the right eye 201b, respectively. For example, the first display optical element can have a lens 104a, and the second display optical element can have a lens 104b. The images displayed on the image display units 103a and 103b are presented to the left eye 201a and the right eye 201b through the corresponding lenses 104a and 104b, respectively. As the lens, the convex lens shown in FIG. 1 can be used.

[0017] The lenses 104a and 104b are driven by actuators 105a and 105b and can move in the direction along the optical axes of the lenses (arrows 107a and 107b). In the present embodiment, although the optical axes 202a and 202b of the lenses 104a and 104b are described as passing through the centers of the image display units 103a and 103b and the left eye 201a and the right eye 201b, respectively, the present invention is not limited thereto.

[0018] FIG. 2 is an explanatory diagram schematically showing a state when lenses 104a and 104b are moved by actuators 105a and 105b. FIG. 2(a) is a diagram showing a state when lenses 104a and 104b are respectively moved close to image display units 103a and 103b. FIG. 2(b) is a diagram showing a state when lenses 104a and 104b are respectively moved close to left eye 201a and right eye 201b. A user of the image display device 100 visually recognizes virtual images 203a and 203b when viewing image display units 103a and 103b with his / her left eye 201a and right eye 201b through lenses 104a and 104b. Here, the positions of virtual images 203a and 203b in the directions of optical axes 202a and 202b with reference to the positions of left eye 201a and right eye 201b are defined as virtual image formation positions X. By changing the positions of lenses 104a and 104b, the virtual image formation position X can be changed. For example, as shown in FIG. 2(a), as lenses 104a and 104b approach image display units 103a and 103b, the virtual image formation position X approaches left eye 201a and right eye 201b. Conversely, as shown in FIG. 2(b), when lenses 104a and 104b approach left eye 201a and right eye 201b, the virtual image formation position X moves away from left eye 201a and right eye 201b. Thus, by moving lenses 104a and 104b by actuators 105a and 105b, the diopter can be changed.

[0019] In this embodiment, when the lenses 104a and 104b approach the image display units 103a and 103b, the virtual image formation position X approaches the left eye 201a and the right eye 201b. However, the present invention is not limited to this configuration. When the lenses 104a and 104b approach the image display units 103a and 103b, the virtual image formation position X may be configured to move away from the left eye 201a and the right eye 201b. Further, in order to change the diopter, a configuration in which the lenses 104a and 104b are moved by the actuators 105a and 105b is shown, but the present invention is not limited to the movement of the optical member. Further, as another configuration for moving the lenses 104a and 104b, for example, a liquid lens may be employed, and an embodiment in which the position of the interface composed of water and oil or the like is changed by an electric signal applied from the actuators 105a and 105b may be used. Further, since the image display device 100 typified by the head-mounted display is arranged and used in the vicinity of the user's ears, it is preferable to use an electromagnetic motor such as a vibration type actuator or a voice coil motor, which has high quietness, as the actuator for changing the diopter. Further, in FIGS. 1 and 2, the lenses 104a and 104b are represented by a single convex lens, but each of them may be a plurality of lenses, and a configuration in which the positions of the predetermined lenses are moved when the diopter is changed may be used.

[0020] Referring to FIG. 3, the parallax images 300 displayed on the image display units 103a and 103b will be described. FIG. 3 is an explanatory diagram of an example of an image. The parallax image 300 is composed of, for example, a left-eye image 301a displayed on the image display unit 103a corresponding to the left eye 201a and a right-eye image 301b displayed on the image display unit 103b corresponding to the right eye 201b.

[0021] In this embodiment, an example is shown in which the parallax video 300 is composed of the left-eye video 301a and the right-eye video 301b, but it is not limited thereto. For example, a configuration may be adopted in which display processing is performed by the display processing unit 102 based on three-dimensional data, and a parallax video is generated and displayed on each of the two video display units 103a and 103b. Further, a video captured by a camera mounted on the video display device 100 may be treated as at least a part of the parallax video 300. With such a configuration, it becomes possible to display a video in the form of an extended reality space on the video display device 1. For example, a parallax video 300 is created by superimposing a video captured by a camera mounted on the video display device 1 and a video based on three-dimensional data created in advance, and a composite video is displayed.

[0022] For example, as shown in FIG. 3(a), when the position where the user's line of sight intersects is exactly the same as the screen of the display video, the videos 301a and 301b in the display video appear to be in the same position as the video display unit 103. Further, as shown in FIG. 3(b), when the position where the videos 301a and 301b in the display video intersect the user's line of sight is in front of the video display unit 103, they appear to pop out with respect to the video display unit 103. Furthermore, as shown in FIG. 3(c), when the position where the videos 301a and 301b in the display video intersect the user's line of sight is behind the video display unit 103, the video appears to be much deeper in the screen with respect to the video display unit 103.

[0023] In this embodiment, the videos 301a and 301b each show one case, but it is not limited thereto. For example, a configuration in which a plurality of objects are displayed in a video captured by a camera may be adopted. In that case, line-of-sight detection means 106a and 106b as shown in FIG. 1 that can detect the line-of-sight directions of the user's left eye 201a and right eye 201b are mounted on the device, and processing is performed to treat the fixation point at which the user's line of sight is directed as the videos 301a and 301b. The line-of-sight detection means can use an infrared illumination unit and a line-of-sight detection camera, etc.

[0024] The diopter adjustment amount calculation unit 111 calculates the diopter adjustment amount based on the depth information at the position of the fixation point determined from the detection results by the line-of-sight detection means 106a and 106b. Based on the calculated diopter adjustment amount, the control unit 108 outputs a drive command to drive the actuators 105a and 105b to perform diopter adjustment. The diopter is adjusted by changing the respective intervals between the video display units 103a and 103b and the lenses 104a and 104b. For example, when the user changes the fixation point, the diopter adjustment by the line-of-sight detection means 106a and 106b is executed in real time.

[0025] Note that the control unit 108 is a so-called microcomputer and may be composed of electrical components such as an arithmetic unit (CPU), a memory for storing a program, and a memory as a work area where the program is developed. In that case, the control unit 108 plays a role of generating a signal having information for controlling the drive of the actuator 105.

[0026] FIG. 4 is a diagram for explaining the convergence angle of the eyeballs and the diopter when gazing at an object. FIG. 4(a) shows the state at the time of gazing in the real world, and FIG. 4(b) shows the state at the time of gazing in the video display device 100.

[0027] In FIG. 4(a), in the real world, the user is in a state of gazing at an object 401 located at a position separated by a distance A. The line of sight of the user's left eye 201a and the line of sight of the user's right eye 201b intersect on the object 401 to form an angle α. The angle α corresponds to the convergence angle when the user gazes at the object 401. Therefore, in the real world, the distance corresponding to the convergence angle α and the distance A corresponding to the diopter are always in a state of coincidence.

[0028] On the other hand, in FIG. 4(b), the video display device 100 is in a state where the user is gazing at an object 401 located at a distance A. The convergence angle α is the same as in the case of the real world shown in FIG. 4(a). The virtual image position 402 is the virtual image position when the user views the video display units 103a and 103b through lenses 104a and 104b (not shown), respectively. The virtual image position 402 is located at a distance B from the left eye 201a and the right eye 201b. By giving the convergence angle α to the virtual image position 402, the user visually recognizes as if he / she is actually at the object 401. However, unlike the real world, in the video display device 100, the distance corresponding to the convergence angle α does not match the distance B corresponding to the diopter. This is called the contradiction between convergence and diopter adjustment. If this state continues, the user's drunkenness and fatigue will increase.

[0029] Therefore, as shown in FIG. 4(c), the virtual image position 402 can be changed by changing the intervals between the video display units 103a and 103b and the lenses 104a and 104b (not shown). For example, when it is detected by the line-of-sight detection means that the user is gazing at the object 401, the interval between the display unit and the lens is changed so that the virtual image position 402 at the distance B becomes the distance A. Thereby, as shown in FIG. 4(a), the distance corresponding to the convergence angle and the distance corresponding to the diopter match, and by making it a more natural state, drunkenness and fatigue can be reduced. When changing the interval between the display unit and the lens, at least one of the display unit and the lens may be driven.

[0030] The state detection unit 109 in FIG. 1 detects the physiological state or psychological state of the user, and for example, detects the user's heartbeat, electrocardiogram, respiration, electrooculogram, skin potential, and center of gravity.

[0031] Regarding the heartbeat, the user's heartbeat is measured, the average value of the instantaneous heart rate, the respiratory component during heart rate variation, and the magnitude of the Mayer wave component during heart rate variation are determined, and at least one or more of these are used as the detection value.

[0032] Regarding the electrocardiogram, measure the electrocardiogram of the user, determine the high-frequency component (HF), low-frequency component (LF) of the heartbeat variation, or the ratio of HF to LF, which is the magnitude of a specific frequency component of the baseline variation of the electrocardiogram, and use at least one of these as a detection value.

[0033] Regarding respiration, measure the respiration frequency, magnitude of respiration, and irregularity of respiration of the user, and use at least one or more of these as a detection value.

[0034] Regarding the electrooculogram, measure the number of blinks, cumulative number, cumulative count, change rate, and blink interval of the user, and use at least one of these as a detection value.

[0035] Also, measure the center of gravity of the user and use the magnitude of the center of gravity fluctuation as a detection value.

[0036] Output the detection value detected by the state detection unit 109 to the state determination unit 110, and determine whether the user is drunk or fatigued by comparing the detection value with a previously recorded normal value, which is a predetermined value. Note that not just any one of the electrocardiogram, respiration, electrooculogram, skin potential, and center of gravity, but a combination of multiple ones can also be used to determine the physiological or psychological state.

[0037] In the case of skin potential, it is advisable to make the determination based on the magnitude of its resistance component. In the case of the center of gravity, it is advisable to make the determination based on the center of gravity fluctuation.

[0038] When it is determined that the user is drunk or fatigued, the control unit 108 drives the actuators 105a and 105b to move the lenses 104a and 104b toward the video display unit side to change the diopter. The state detection unit 109 and the state determination unit 110 do not necessarily have to be part of the video display device, and they can be configured to wirelessly transmit and receive signals so that signal transmission and reception are possible. Conversely, by adopting an integrated configuration with the video display device, the user of the head-mounted display can immediately utilize the state detection function without going through remote communication.

[0039] Referring to the flowchart of FIG. 5, the operation of the first embodiment will be described. The program corresponding to the flowchart of FIG. 5 is stored in the storage unit within the arithmetic processing unit. The control unit 108 indicates a CPU, a memory, etc., and each process shown in the flowchart of FIG. 5 is realized by the CPU expanding a predetermined program stored in the memory. The configuration of the control unit 108 can also adopt an integrated configuration with the video display device or not adopt it.

[0040] First, at S501, the state detection unit 109 is used to detect the physiological or psychological state of the user. Next, at S502, based on the detected value, the drunkenness and fatigue state of the user is determined. If the detected value is equal to or greater than the desired value, at S503, the movement amount is calculated so as to move the lenses 104a and 104b in a direction away from the video display units 103a and 103b, and at S504, the control unit 108 drives the actuators 105a and 105b. This movement amount may be determined according to the detected value, and the movement amount may be increased as the detected value increases and decreased as the detected value decreases. By doing so, it is possible to reduce drunkenness and fatigue by making it impossible to clearly see the displayed parallax video without focusing and reducing the amount of information entering the left eye 201a and the right eye 201b to relax the eye muscles.

[0041] In S502, when the detected value is less than or equal to the desired value, in S505, using the line-of-sight detection means 106a and 106b, the line-of-sight of each of the user's left eye 201a and right eye 201b is detected.

[0042] Next, in S506, the control unit 107 performs a process of determining a fixation point from the line-of-sight of the left eye 201a and the line-of-sight of the right eye 201b. When calculating the fixation point, the average value regarding the line-of-sight of the left eye 201a and the right eye 201b can be used.

[0043] Next, in S507, the diopter adjustment amount calculation unit 111 performs a process of calculating the diopter adjustment amount at the position of the fixation point of the video displayed on the video display units 103a and 103b. Specifically, the parallax between the video at the fixation point position of the left eye and the video at the fixation point position of the right eye is calculated, and the diopter adjustment amount is derived based on the depth information corresponding to this parallax. For example, by providing table data associating the parallax with the diopter adjustment amount, the diopter adjustment amount corresponding to the parallax can be calculated. Alternatively, the diopter adjustment amount calculation unit 111 may calculate the diopter adjustment amount from the parallax using a mathematical formula showing the relationship between the parallax and the diopter adjustment amount.

[0044] Next, in S508, based on the diopter adjustment amount calculated by the diopter adjustment amount calculation unit 111, the actuators 105a and 105b are driven by the control unit 108. As a result, an operation of changing the distance between the video display units 103a and 103b and the lenses 104a and 104b is performed. Since the above operations are performed every time the fixation point is changed, the diopter can be adjusted in real time to change the diopter.

[0045] FIG. 6 shows the detection values of the user's physiological or psychological state and the lens positions of the configuration in FIG. 1. As shown in FIG. 6, during the period from time t0 to t1, the fixation point is calculated from the line of sight detected by the line-of-sight detection means, and the diopter adjustment is performed in real time in the directions of arrows 107a and 107b according to the depth information of the fixation point. When the state detection value detected by the state detection unit exceeds a predetermined value at time t1, the actuators 105a and 105b are moved so as to bring the lenses 104a and 104b closer to the user side so as to move away from the video display units 103a and 103b. After that, when the detected value falls below a desired value at time t2, the fixation point is calculated again from the line of sight detected by the line-of-sight detection means, and the diopter adjustment is performed in real time in the directions of arrows 107a and 107b according to the depth information of the fixation point.

[0046] Note that, taking the reciprocal of this state detection value as the evaluation target, a configuration can be adopted in which the case where the reciprocal of the state detection value falls below a certain value is used as a criterion, and in this case, it is also synonymous with "exceeding a predetermined value".

[0047] In this embodiment, since the lens 104a corresponding to the left eye 201a and the lens 104b corresponding to the right eye 201b can be driven by independent actuators 105a and 105b, it is possible to cope with users with different left and right visual acuities. That is, a configuration can be adopted in which the position of at least one of the first and second display optical elements is changed.

[0048] According to this embodiment, while performing diopter adjustment according to the depth information of the fixation point of the line of sight, the actuators are driven so that the lenses 104a and 104b move away from the video display units 103a and 103b according to the user's drunkenness or fatigue state. As a result, the video displayed on the video display unit is visually recognized as being blurred, and by reducing the amount of information obtained by the user from the video, it is possible to reduce the accumulated drunkenness and fatigue due to long-term use.

[0049] Also, in the above example, it was described that the actuator is moved so that the video display unit and the lens move away from each other. However, the present invention is not limited to this, and the actuator may be moved so that the video display unit and the lens approach each other, and the same effect can be obtained. In this case, when the value detected by the state detection unit 109 exceeds a predetermined value, the lenses 104a and 104b are moved by the actuators 105a and 105b so as to approach the video display units 103a and 103b.

[0050] Note that, heretofore, the description has been made on the premise of a configuration in which the diopter adjustment is performed based on the depth information of the fixation point detected by the line-of-sight detection means 106a and 106b. However, the present invention is not limited to this, and the diopter adjustment may be manually performed in a configuration as shown in FIG. 7. FIG. 8 shows the detected values of the physiological or psychological state of the user and the lens positions of the configuration of FIG. 7. In the case of such a configuration, as shown in FIG. 8, at time t0, the user manually adjusts the diopter to the position adjusted according to the video being viewed, and this position is set as the reference position of the lens. When the value detected by the state detection unit exceeds a predetermined value at time t1, the actuator is moved so that the lens approaches the user side away from the display unit. Thereafter, when the detected value is below the desired value at time t2, the actuator is moved so as to return to the reference position of the lens manually adjusted at time t0, which is the same as that at time t0.

[0051] <Second Embodiment> In the first embodiment described above, the operation method of the actuators 105a and 105b driven by the control unit 108 using the value detected by the state detection unit 109 will be described. Since the principle, configuration, etc. are the same as those in the first embodiment, they will be omitted.

[0052] Referring to the flowchart of FIG. 9, the operation of the second embodiment will be described. The program corresponding to the flowchart of FIG. 9 is stored in the storage unit in the arithmetic processing unit. The control unit 108 indicates a CPU, a memory, etc., and each process shown in the flowchart of FIG. 9 is realized by the CPU expanding a predetermined program stored in the memory.

[0053] First, at S1001, the state detection unit 109 is used to detect the physiological or psychological state of the user. Next, at S1002, based on the detected value, the degree of drunkenness and fatigue of the user is determined. If the detected value is equal to or less than the desired value, at S1003, in the control unit 108, the maximum driving speeds of the actuators 105a and 105b are set to A (for example, 100 mm / s). If the detected value is greater than the desired value, at S1004, in the control unit 108, the maximum driving speeds of the actuators 105a and 105b are set to B, which is smaller than A (for example, 50 mm / s). By changing the maximum driving speed in this way, the amount of change in the focus on the user's image can be suppressed, and the eyes' attempt to follow a sudden change in focus can be reduced. As a result, even during long-term video viewing, by reducing the burden on the user, an increase or accumulation of drunkenness or fatigue can be reduced.

[0054] Next, at S1005, using the line-of-sight detection means 106a and 106b, the line of sight of each of the user's left eye 201a and right eye 201b is detected.

[0055] Next, at S1006, the control unit 108 performs a process of determining a fixation point from the line of sight of the left eye 201a and the line of sight of the right eye 201b. When calculating the fixation point, the average value regarding the lines of sight of the left eye 201a and the right eye 201b can be used.

[0056] Next, at S1007, the diopter adjustment amount calculation unit 111 performs a process of calculating the diopter adjustment amount at the position of the fixation point of the video displayed on the video display units 103a and 103b. Specifically, the parallax between the video at the fixation point position of the left eye and the video at the fixation point position of the right eye is calculated, and the diopter adjustment amount is derived based on the depth information corresponding to this parallax. For example, by providing table data associating the parallax with the diopter adjustment amount, the diopter adjustment amount corresponding to the parallax can be calculated. Alternatively, the diopter adjustment amount calculation unit 111 may calculate the diopter adjustment amount from the parallax using a mathematical formula showing the relationship between the parallax and the diopter adjustment amount.

[0057] Next, at S1008, based on the diopter adjustment amount calculated by the diopter adjustment amount calculation unit 111, the control unit 108 drives the actuators 105a and 105b. As a result, an operation is performed to change the distance between the video display units 103a and 103b and the lenses 104a and 104b. Since the above operation is performed every time the fixation point is changed, diopter adjustment can be performed in real time to change the diopter.

[0058] FIG. 10 shows the detection values of the physiological or psychological state of the user and the maximum driving speeds of the actuators 105a and 105b. As shown in FIG. 10, from time t0 to t1 when the value detected by the state detection unit 109 is less than a predetermined value, the maximum driving speeds of the actuators 105a and 105b are set to A. From time t1 to t2 when the value detected by the state detection unit 109 is greater than or equal to the predetermined value, the maximum driving speed is set to B which is smaller than the maximum driving speed A. From time t2 to t3 when the value detected by the state detection unit 109 is less than the predetermined value, the maximum driving speed is set to A again.

[0059] Note that although an example of changing the maximum driving speed has been shown here, it is not limited to this, and the control gain and control period may be changed in the same way to obtain a similar effect. The control gain is the ratio of the control output required to change the actuator by a certain amount. By reducing this ratio, the responsiveness can be suppressed, the amount of change in the focus on the user's video can be suppressed, and the eyes' attempt to follow a sudden change in focus can be reduced. As a result, even during long-time video viewing, by reducing the burden on the user, an increase or accumulation of drunkenness or fatigue can be reduced. The control period is the time interval for issuing commands in the control of the actuator. By widening this time interval, the update frequency can be suppressed, the amount of change in the focus on the user's video can be suppressed, and the eyes' attempt to follow a sudden change in focus can be reduced. As a result, even during long-time video viewing, by reducing the burden on the user, an increase or accumulation of drunkenness or fatigue can be reduced. Also, when the value detected by the state detection unit 109 is equal to or greater than a predetermined value, a plurality of the maximum driving speed, control gain, and control period may be changed simultaneously.

[0060] So far, an example has been shown in which the maximum driving speed, control gain, and control period are changed based on whether the detection value of the state detection unit 109 exceeds a predetermined value. However, it is not limited to this, and as shown in the flowchart of FIG. 11, the maximum driving speed, control gain, and control period may be changed according to the detection value. In this case, first, at S1201, the state detection unit 109 is used to detect the physiological or psychological state of the user. Next, at S1202, based on the detected value, the control unit 108 sets the maximum driving speed of the actuators 105a and 105b. For example, by providing table data associating the detection value of the physiological or psychological state with the maximum driving speed, the maximum driving speed can be calculated according to the detection value of the physiological or psychological state. Alternatively, the maximum driving speed may be calculated by a mathematical formula showing the relationship between the detection value of the physiological or psychological state and the maximum driving speed. By changing the maximum driving speed in this way, the amount of change in the focus on the user's video can be suppressed, and the eyes can be reduced from trying to follow a sudden change in focus. As a result, even during long-term video viewing, by reducing the burden on the user, an increase or accumulation of drunkenness or fatigue can be reduced, and the same effect as the above-described example can be obtained.

[0061] Note that the operations from S1203 to S1206 in FIG. 11 are the same as the operations from S1005 to S1008 in the flowchart of FIG. 9 described above, and thus the description is omitted.

[0062] FIG. 12 shows the detection value of the physiological or psychological state of the user and the maximum driving speed of the actuators 105a and 105b. As shown in FIG. 12, the maximum driving speed of the actuators 105a and 105b is set stepwise according to the value detected by the state detection unit 109.

[0063] Note that, although an example of changing the maximum driving speed has been shown here, the present invention is not limited to this, and the control gain and control period may be changed instead, and the same effect can be obtained. Further, when the value detected by the state detection unit 109 is equal to or greater than a predetermined value, a plurality of the maximum driving speed, control gain, and control period may be changed simultaneously.

[0064] As described above, the present invention has been described in detail based on its preferred embodiments. However, the present invention is not limited to these specific embodiments, and various forms within the scope not departing from the gist of the present invention are also included in the present invention. It is also possible to provide a control method for executing each of the above-described steps and a computer-readable non-transitory program for executing the control method.

[0065] For example, a program that realizes one or more functions of the above-described embodiments can be supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device can also read and execute the program to realize the functions. It is also possible to realize the functions by a circuit (for example, ASIC) that realizes one or more functions.

Explanation of Reference Numerals

[0066] 100 Video display device 101 Video acquisition unit 102 Display processing unit 103 Video display unit 104 Lens 105 Actuator 106 Line-of-sight detection means 107 Driving direction 108 Control unit 109 State detection unit 110 State determination unit 111 Depth information calculation unit 201a Left eye 201b Right eye 202 Optical axis 203 Virtual image

Claims

1. First and second video display units that respectively display first and second videos for the user's right and left eyes, First and second display optical elements respectively corresponding to the first and second video display units, An actuator that changes the position of the display optical element, and a video display device comprising: A video display device that drives the actuator based on a detection result of a physiological state or a psychological state of a user during use of the video display device, thereby changing the position of at least one of the first and second display optical elements.

2. The video display device according to claim 1, wherein when the detection result of the physiological state or the psychological state becomes equal to or greater than a predetermined value, the actuator is driven so that at least one of the first video display unit and the first display optical element, and the second video display unit and the second display optical element are in positions separated from each other.

3. The video display device according to claim 1, wherein when the detection result of the physiological state or the psychological state becomes equal to or greater than a predetermined value, the actuator is driven so that at least one of the first video display unit and the first display optical element, and the second video display unit and the second display optical element are in positions approaching each other.

4. The video display device according to any one of claims 1 to 3, further comprising first and second line-of-sight detection means for respectively performing line-of-sight detection related to the first and second video display units.

5. The video display device according to claim 4, configured to perform the line-of-sight detection without passing through the first and second display optical elements.

6. The video display device according to any one of claims 1 to 3, further comprising a calculation means for calculating a visual acuity adjustment amount corresponding to a parallax between the first video and the second video at a position of a fixation point acquired from the first and second line-of-sight detection means.

7. The video display device according to claim 6, wherein the video display device includes a control unit that outputs a drive command, and the control unit issues the drive command corresponding to the visual acuity adjustment amount to the actuator.

8. The video display device according to any one of claims 1 to 3, further characterized in that a control gain of the actuator is further changed according to a value of the detection result of the physiological state or the psychological state.

9. The video display device according to any one of claims 1 to 3, further comprising changing a control cycle of the actuator according to a value of a detection result of the physiological state or the psychological state.

10. The video display device according to any one of claims 1 to 3, further comprising changing a maximum driving speed of the actuator according to a value of a detection result of the physiological state or the psychological state.

11. The video display device according to claim 4, wherein the first and second line-of-sight detection means include an infrared illumination unit and a line-of-sight detection camera.

12. The video display device according to any one of claims 1 to 3, wherein a detection result of the physiological state or the psychological state is obtained based on at least one of a blink count, a cumulative count, a change rate, and a time interval between blinks according to an electrooculogram of a user of the video display device that has been measured.

13. The video display device according to any one of claims 1 to 3, wherein a detection result of the physiological state or the psychological state is obtained based on a magnitude or a ratio of a frequency component of a baseline fluctuation according to an electrocardiogram of a user of the video display device that has been measured.

14. The video display device according to any one of claims 1 to 3, wherein a detection result of the physiological state or the psychological state is obtained based on a magnitude of a resistance component according to a skin potential of a user of the video display device that has been measured.

15. The video display device according to any one of claims 1 to 3, wherein a detection result of the physiological state or the psychological state is obtained based on at least one of a respiratory frequency, a magnitude of respiration, and an irregularity of respiration of a user of the video display device that has been measured.

16. The video display device according to any one of claims 1 to 3, wherein a detection result of the physiological state or the psychological state is obtained based on a center-of-gravity fluctuation of a center of gravity of a user of the video display device that has been measured.

17. The video display device according to any one of claims 1 to 3, wherein a heart rate of a user of the video display device that has been measured is measured, and a detection result of the physiological state or the psychological state is obtained based on an average value of an instantaneous heart rate, a respiratory component during heart rate fluctuation, and a Mayer wave component during heart rate fluctuation.

18. The video display device according to any one of claims 1 to 3, wherein the display optical element is a lens.

19. The video display device according to any one of claims 1 to 3, wherein the actuator is an electromagnetic motor or a vibration type actuator.

20. A first and a second video display unit that respectively display first and second videos for a user's right eye and left eye, First and second display optical elements respectively corresponding to the first and second video display units, An actuator that changes the position of the display optical element, and a control method for a video display device comprising: A control unit, A step of obtaining a detection result of a physiological state or a psychological state of a user during use of the video display device, A control method for a video display device that executes a step of changing the position of at least one of the first and second display optical elements by driving the actuator based on the detection result.

21. A computer-readable non-transitory program that causes the control unit to execute each step described in claim 20.

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