JPH1093889A - Head mount video display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow the viewer to view a display video image easily to see at a just front side or the like even when its head is turned by moving an imaginary image so as to avoid the imaginary image from tracing a change in the head direction when the head direction of the viewer is changed. SOLUTION: A moving lens 12L and a fixed lens 13L form a left eyepiece optical system 14L to lead a video image light of a left LCD11L to a left eye EL of a viewer on which an HMD(head mounted display) is mounted. A moving lens 12R and a fixed lens 13R form a right eyepiece optical system 14R to lead a video image light of a right LCD11R to a right eye ER of viewer. The viewer views an imaginary image of the displayed video image by viewing the LCD11L, 11R via the left right eyepiece optical systems 14L, 14R. The HMD1 detects a direction of the head of the viewer to move the moving lenses 12L, 12R in response to the detected head direction thereby moving the position of the imaginary image. In this case, the moving amount of the moving lenses 12L, 12R is adjusted so as not to cause a change in the absolute position of the imaginary image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head mounted image display apparatus, so-called HMD, and more particularly, to the position of an image observed according to the direction of the head of an observer wearing the HMD. Is related to the HMD.

[0002]

2. Description of the Related Art In recent years, an image display device having a display element and an eyepiece optical system and configured to be mounted on a head and used has been developed. This video display device is an HMD (Head Mou
It is being widely used as a display device for viewing images of a virtual reality system and personal viewing of television images.

In the virtual reality system, a left and right image with parallax is displayed, and a sensor for detecting the direction of the observer's head is provided on the HMD, and an image in a direction corresponding to the detected direction of the head is displayed. By doing so, it has a high sense of realism. The observer can observe the stereoscopic image, and simply rotate the head,
It is possible to view an image in a desired direction. In the case of television, a left and right image with parallax is not displayed, and a stereoscopic image cannot be observed. Further, since an image in a direction corresponding to the direction of the television camera is captured and displayed, the image displayed on the HMD and the direction of the observer's head are irrelevant.

It is desirable that the HMD be small and light in view of its usage form. For example, a small liquid crystal display (LCD) is used as a display element, and the image light of the LCD is enlarged by an eyepiece optical system to allow the observer to observe the image. There is a configuration in which projection is performed on the eye. In this configuration, the observer observes the virtual image by viewing the image on the LCD through the eyepiece optical system. There is an HMD having a simple configuration that does not include an eyepiece optical system for enlargement and directly observes a display image.

[0005] Even if the observer turns his head or changes his posture, the display element and the eyepiece optical system move with the observer's head, so that the positional relationship between the observer's head and the virtual image changes. do not do. For this reason, the observer always observes the image at a fixed position substantially directly in front. For example, the position of the image observed by the observer is the same regardless of whether the posture is upright and facing forward or lying down. In the virtual reality system, the displayed image changes depending on the direction of the head, but the position of the image is kept constant.

[0006] With the spread of HMD, eye strain due to the use of HMD is becoming a problem. This is mainly due to the fact that the image observation by the HMD requires an unnatural eye movement different from the observation of an object in daily life. Therefore, the distance from the eye to the image (a virtual image in the case of observing a virtual image with an eyepiece optical system), that is, the diopter is set according to the size of the image, and the left and right images having parallax for stereoscopic viewing are displayed. For example, proposals have been made to set the angle between the lines of sight of the eyes, that is, the convergence, in accordance with the parallax between the left and right images.

[0007]

However, eye fatigue due to the use of the HMD is not caused only by inappropriate setting of diopter and convergence. In the conventional HMD, the relative position between the image and the eye is fixed, which is one factor that causes an unnatural movement of the eye. If you rotate your head, the video will follow and move.To see the periphery of the displayed video, instead of turning your head, change the direction of your eyes. Only the gaze needs to be changed. At this time, if the displayed image is small, the amount of change in the line of sight is small, so there is no particular problem. However, if the image is displayed large, the line of sight must be changed greatly, and this burdens the eyes.

Further, even when a person intends to keep the head stationary, the head is slightly moving. Even when the stationary head is observed to observe a stationary object, the position of the stationary object entering the eyes is actually delicate. Has changed. In daily life, a person is accustomed to observing an object in such a state. However, in the HMD, since the image moves following the movement of the head, even if the head moves slightly, the image does not move. Therefore, an unnatural observation different from daily life is performed, which also causes eyestrain.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce eye fatigue when using an HMD due to the fact that the relative position of an image with respect to the observer's eyes is always constant regardless of the direction of the head.

[0010]

In order to achieve the above object, the present invention has a display means for displaying an image and an eyepiece optical system, and observes a virtual image of the image displayed on the display means by the eyepiece optical system. Detecting means for detecting the orientation of the observer's head, in a head-mounted image display device provided to the observer's eyes,
Changing means for changing the position of the virtual image with respect to the observer according to the orientation of the observer's head detected by the detection means.

The observer observes the display on the display means via the eyepiece optical system to observe a virtual image of the displayed image. The direction of the observer's head is detected by the detecting means. When the observer rotates the head, the display means and the eyepiece optical system rotate with the head, but the position of the virtual image observed by the observer is changed by the change means according to the detected head direction. You. Therefore, the relative position of the virtual image with respect to the eye changes depending on the direction of the head. When the direction of the head changes, the changing unit can change the relative position of the virtual image with respect to the eyes, for example, so as to cancel the change in the direction of the head.

In the above image display device, the changing means changes the position of the virtual image by displacing the eyepiece optical system. If the eyepiece optical system is displaced in the direction perpendicular to the optical axis of the eyepiece optical system, the direction of light incident on the observer's eye changes, and the virtual image moves in the direction perpendicular to the optical axis of the eyepiece optical system. . In this case, the position of the displayed image on the display means does not change.

[0013] The changing means may be configured to change the position of the virtual image by changing the display position of the image on the display means. If the display position of the video changes, the position of the virtual image also changes.

The detecting means detects the direction and the amount of deviation of the orientation of the observer's head from the reference direction, and the changing means detects the position of the virtual image in the direction opposite to the direction of the detected deviation. It is good to move by the amount of shift. The direction of the observer's head is detected as a deviation from the reference direction, and the position of the virtual image is moved so as to completely cancel the detected deviation. Therefore, the absolute position of the virtual image does not change, and the virtual image is perceived by the observer as an object that does not move, like an everyday stationary object. When the observer turns his or her head in that direction in an attempt to gaze at an area at the periphery of the visual field, the area comes to the center of the visual field. When the observer's head slightly moves, the relative position of the virtual image with respect to the eye changes by a small amount.

The detecting means detects the amount of deviation of the direction of the observer's head from the reference direction, and when the amount of deviation detected by the detecting means is less than a predetermined amount, the changing means detects the detected observer's head. Change the position of the virtual image according to the orientation of the head of
When the amount of displacement detected by the detecting means is equal to or more than a predetermined amount, the changing means sets the position of the virtual image to a predetermined position, and the detecting means sets the detected head direction of the observer as a reference direction. You may do so.

The direction of the observer's head is detected as a deviation from the reference direction, and the operation of the changing means changes depending on whether or not the amount of the deviation is equal to or more than a predetermined amount. When the amount of displacement is less than the predetermined amount, the changing means changes the position of the virtual image according to the detected orientation of the observer's head. At this time, as described above, the relative position of the virtual image with respect to the eye can be changed so that the absolute position of the virtual image does not change. When the amount of displacement is equal to or more than a predetermined amount, the changing means sets the position of the virtual image to a predetermined position regardless of the direction of the observer's head, and the detecting means sets the detected direction of the observer's head. Is the new reference direction. Thereafter, the detecting means detects a deviation of the head direction from the new reference direction, and the changing means sets the position of the virtual image based on a comparison result between the detected deviation amount and a predetermined amount.

Therefore, when the amount of rotation of the observer's head is small and less than a predetermined amount, the virtual image is moved from a predetermined position in accordance with the amount of rotation from the reference direction, and the amount of rotation of the head is large and the predetermined amount. In the above case, the reference direction is updated and the virtual image is reset to a predetermined position. The predetermined position is the position of the virtual image when the direction of the observer's head matches the reference direction, and is the reference position of the virtual image.
This reference position may be, for example, a position directly in front of the observer's eye.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an optical configuration of a first embodiment of the HMD of the present invention. The HMD 1 is a pair of left and right color liquid crystal display devices (LCD) for displaying images.
11L and 11R, a pair of left and right movable lenses 12L and 12R, and a pair of left and right fixed lenses 13L and 13R.
The ratio of the vertical and horizontal lengths of the display range of the LCDs 11L and 11R is 2:
3.

The movable lens 12L and the fixed lens 13L form a left eyepiece optical system 14L, and convert the image light of the left LCD 11L to H
The MD1 is guided to the left eye EL of the observer. Similarly, the movable lens 12R and the fixed lens 13R are connected to the right eyepiece optical system 1
4R, and the image light of the right LCD 11R is transmitted to the right eye ER of the observer.
Lead to. LCD via left and right eyepiece optical systems 14L, 14R
By viewing 11L and 11R, the observer observes a virtual image of the displayed image.

The left and right eyepiece optical systems 14L and 14R are set so that the size of the virtual image is larger than the size of the displayed image, so that the image can be enlarged and observed. LCD 11L, size of 11R, eyepiece optical system 14L,
14R magnification, LCD 11L, 11R and eyepiece optical system 14L,
The distance and the like of 14R are set so that the horizontal angle of view of the virtual image is 60 °, and the vertical angle of view of the virtual image is 42 ° from the ratio of the length and width of the display range. The left and right viewing angles are set to be at least twice the angle of view of the virtual image, that is, at least 120 ° in the horizontal direction and at least 84 ° in the vertical direction.

The left movable lens 12L is movable in any direction perpendicular to the optical axis of the fixed lens 13L, and the right movable lens 12R is similarly movable in any direction perpendicular to the optical axis of the fixed lens 13R. It can move in any direction. Movable lens 12
When L and 12R are not moving, the respective optical axes are set to coincide with the optical axes of the fixed lenses 13L and 13R. When the movable lenses 12L and 12R are moved, the optical axes AXL and AXR of the eyepiece optical systems 14L and 14R are tilted.
The position of the virtual image observed by the observer changes.

In the HMD 1 of the present embodiment, the direction of the observer's head is detected, and the movable lenses 12L and 12R are moved in accordance with the detected head direction to change the position of the virtual image. At this time, the moving amount of the movable lenses 12L and 12R is adjusted so that the absolute position of the virtual image does not change. For example, when the head is rotated upward by 20 ° in the vertical direction, the virtual image is moved downward by 20 ° in the vertical direction.

FIG. 2 shows an outline of the configuration from the detection of the head orientation to the change of the virtual image position. An HMD 1 is an angular velocity sensor 2 for detecting a horizontal rotational speed of the head.
1H and an angular velocity sensor 21V for detecting a vertical rotation speed. Further, the integrating circuits 22H and 22V integrate the detected angular velocities in the horizontal direction and the vertical direction, respectively, and determine the amount of rotation in the horizontal direction and the vertical direction.
It has.

Here, a vibrating gyroscope using piezoelectric ceramics is used as the angular velocity sensors 21H and 21V. The piezoelectric vibrating gyroscope detects a rotational motion and outputs a voltage linearly corresponding to the angular velocity. The direction of the rotational movement can be known from the sign of the difference between the output voltage when the piezoelectric vibrating gyroscope performs the rotational movement and the output voltage when the piezoelectric vibrating gyroscope is at rest, and the magnitude of the angular velocity can be known from the absolute value of the difference. The integration circuits 22H and 22V are provided with an angular velocity sensor 21H,
The quiescent output voltage is subtracted from the 21V output voltage and the difference voltage is integrated over time. In the integration result thus obtained, the absolute value indicates the amount of rotation of the head from the start of integration, and the sign indicates the rotation direction with respect to the direction of the head at the start of integration.

The outputs of the integrating circuits 22H and 22V are supplied to a microcomputer 23 for controlling the movement of the movable lenses 12L and 12R. Microcomputer 23
Calculates the rotation angle of the head by multiplying a given integration result by a constant for converting into an angle. The movable lenses 12L and 12R for preventing the absolute position of the virtual image from being changed from the calculated horizontal and vertical rotation angles of the head.
The movement direction and the movement amount of the are calculated.

The movable lenses 12L and 12R are moved by lens driving circuits 25L and 25R, respectively, and the movement amount of each lens is detected by lens movement amount detection circuits 26L and 26R. The microcomputer 23 monitors the outputs of the lens movement amount detection circuits 26L and 26R and moves the lenses by the lens driving circuits 25L and 25R in order to move the movable lenses 12L and 12R in the calculated directions by the calculated amount. Control. FIG. 3 schematically shows a configuration for movement of the lens and its detection.

Each of the lens driving circuits 25L and 25R has 2
It consists of two electromagnetic actuators 27H and 27V. The electromagnetic actuators 27H and 27V each have a permanent magnet fixed to the HMD1 main body and a coil fixed to a support member fixed to the movable lens. It is a moving coil type. The actuator 27H moves the movable lens in the horizontal direction (arrow X direction), and the actuator 27V moves the movable lens in the vertical direction (arrow Y direction). The amount of movement is adjusted by adjusting the amount of current flowing through the coil, and the movable lens can be moved in any direction in the XY plane perpendicular to the optical axis of the eyepiece optical system.

The lens movement detecting circuits 26L and 26R are respectively composed of two electromagnetic sensors 28H and 28V. Each of the electromagnetic sensors 28H and 28V has a permanent magnet fixed to the main body of the HMD 1 and a coil fixed to a support member fixed to the movable lens. A current corresponding to the moving distance of the movable lens flows through the coil in the magnetic field, and the amount of movement of the lens is known from this current. The electromagnetic sensors 28H and 28V detect the horizontal and vertical movement amounts, respectively. Movement of the movable lens in all directions in the XY plane is detected separately in horizontal and vertical directions.

The LCDs 11L and 11R are driven by LCD drive circuits 31L and 31R, respectively. A video signal is supplied to the LCD drive circuits 31L and 31R irrespective of the detection of the direction of the head and the control of the movement of the lens. Here, the video signals are individually supplied to the left and right LCD driving circuits 31L and 31R, and the left and right video signals photographed from different directions are supplied to the LCD driving circuits 31L and 31R.
1R can be supplied. Thereby, the left and right images having parallax are displayed on the LCDs 11L and 11R, and the images can be observed as a stereoscopic image.

When a single video signal is provided as in a television, the same video signal is
The power is supplied to the D drive circuits 31L and 31R. In this case, a stereoscopic image cannot be observed, but by observing the image with both eyes instead of one eye, eye fatigue is reduced.

In the HMD 1 having the above configuration, when the detected amount of rotation of the observer's head is 0, that is, when the head is oriented in the reference direction, the amount of movement of the movable lenses 12L and 12R is set in the horizontal direction. The virtual image is set to 0 in both the vertical direction and the virtual image is positioned directly in front of the observer's head. This position is called a reference position. The reference position is located at the center of the field of view in the left-right center and in the up-down center. When the detected amount of rotation of the head is not 0, that is, when the direction of the head is shifted from the reference direction, the position of the virtual image is shifted from the reference position according to the direction and amount of the shift.

FIG. 9 shows an example of the position of the virtual image in the visual field when the direction of the head coincides with the reference direction. In FIG. 9, FVL and FVR represent left and right visual fields, respectively, and IML and IMR represent left and right virtual images, respectively. (A) shows a state where the head is oriented in the reference direction, and the virtual images IML and IMR are located at the center reference positions of the visual fields FVL and FVR. In this state, the observer sees the virtual images IML and IMR directly in front.

(B) shows a state in which the observer tries to gaze at the lower right object and turns the head about 25 ° to the right and about 15 ° downward from the state of (a). , Virtual image IM
L and IMR have moved leftward and upward from the reference position. At this time, the relative position of the virtual image with respect to the observer's eyes has changed, but the absolute position of the virtual image with respect to the center of rotation of the head has not changed. Further, there is no change in the image display position on the LCDs 11L and 11R.

As described above, the position of the virtual image is changed so as to cancel the deviation according to the deviation of the head direction from the reference direction. Movable lens 1 for moving this virtual image
The movement amounts of 2L and 12R correspond one-to-one with the rotation amounts of the head. However, the two are not in a proportional relationship, and the movable lens 12
It is represented by a complicated trigonometric function involving the curvature and refractive index of L and 12R.

The movable range of the movable lenses 12L and 12R is such that the head is ±± both horizontally and vertically from the reference direction.
It is set so that it can follow even if it is turned up to 30 °. As described above, the horizontal angle of view of the virtual image is 60 °, and the rotation of the head by 30 ° in the horizontal direction is equivalent to moving the virtual image by half of the horizontal length. When the virtual image is moved from the reference position by this amount, one end in the horizontal direction is located at the left and right center of the virtual image at the reference position, and the virtual image exists in the right half or the left half in the visual field. Since the viewing angle in the horizontal direction is 120 ° or more, a virtual image can be observed at this time.

In the vertical direction, the angle of view of the virtual image is 42 °, and by the rotation of 21 ° from the reference direction of the head,
The virtual image moves to the upper half or the lower half in the field of view. Since the vertical viewing angle is 84 ° or more, no eclipse occurs at this time, and the entire area can be observed.

When the reference direction of the head is fixed and the position of the virtual image is always set in accordance with the deviation of the head direction from this reference direction, the observer can change the range in which the head direction can be changed. Will be limited. Therefore, when the direction of the head changes greatly enough to cause the blur, the virtual image is returned to the reference position, and the direction of the head at that time is set as a new reference direction. After that, the position of the virtual image is set according to the deviation of the head direction from the new reference direction.

More specifically, the virtual image position and the reference direction are reset when the head has turned 30 ° or more in the horizontal direction or 21 ° or more in the vertical direction. However, since the observer may change the orientation of the head momentarily,
The resetting is performed only when the rotation of the head over these angles is continuously detected for a predetermined time or more. A large rotation in a very short time is processed as usual, even if a partial area cannot be observed due to being shaken, and the movable lens 12L,
The virtual image is moved according to the amount of rotation within the movable range of 12R. The reference time for this determination may be set arbitrarily, and is 2 seconds here.

For this time measurement, the microcomputer 23 is provided with a timer 24. Further, a reset switch 29 is provided so that the virtual image position and the reference direction can be reset at any time according to the wishes of the observer.

FIG. 4 shows the flow of processing relating to the change of the virtual image position in the HMD 1. First, the integration circuits 22H, 22V
Is initialized, and the integrated value, that is, the detected amount of rotation of the head is set to 0 in both the horizontal and vertical directions (step # 10).
5). At the same time, the movable lenses 12L and 12R are set to the initial positions where the optical axes coincide with the optical axes of the fixed lenses 13L and 13R (# 110), and the left and right virtual images are set to the reference positions.
Next, the value of the flag is set to 0 (# 115), and the timer 2 is set.
4 is stopped (# 120).

The detection of the rotation of the head and the change of the virtual image position are repeatedly performed. The flag is used to store whether or not the detected rotation amount is equal to or more than a predetermined amount. The value is set to 1 when the amount is equal to or more than the fixed amount, and set to 0 when the amount is less than the predetermined amount. The timer 24 is started when a rotation amount equal to or more than a predetermined amount is detected, and is stopped when the rotation amount is less than the predetermined amount. The timer 24 is operating when the value of the flag is 1, and is stopped when the value of the flag is 0.

After the completion of the initialization processing, it is determined whether or not the observer has operated the reset switch 29 (# 12).
5). When the reset switch 29 is on, # 105
And the initialization process is performed. When the reset switch 29 is off, the outputs of the angular velocity sensors 21H and 21V are integrated by the integration circuits 22H and 22V (# 130), and the horizontal rotation amount RH and the vertical rotation amount RV of the head are determined from the integration results. It is calculated (# 135). Next, it is determined whether or not the calculated horizontal rotation amount RH and vertical rotation amount RV are equal to or greater than predetermined amounts RH0 and RV0, respectively (# 140). The predetermined amounts RH0 and RV0 are set to 30 ° and 21 °, respectively, as described above.

When the horizontal rotation amount RH is less than the predetermined amount RH0 and the vertical rotation amount RV is less than the predetermined amount RV0, the amount of movement of the movable lenses 12L and 12R in the horizontal and vertical directions is calculated. Then, by moving the movable lenses 12L and 12R by the calculated amount (# 150), the relative position of the virtual image with respect to the eye is changed. Then, the setting of the flag is determined (# 155). When the value is 0, the process returns to # 125. When the value of the flag is 1, the value of the flag is set to 0 (# 160), the operating timer 24 is stopped (# 165), and the process returns to # 125.

In the determination of # 140, when the horizontal rotation amount RH is equal to or more than the predetermined amount RH0, or when the vertical rotation amount RV is equal to or more than the predetermined amount RV0, the setting of the flag is determined (# 170). Here, the value of the flag becomes 0 when the rotation amount is less than the predetermined amount and when the rotation amount becomes more than the predetermined amount for the first time, and the value becomes 1 when the rotation more than the predetermined amount continues. If you are. When the flag value is 0, the flag value is set to 1 and the current detection result is stored (# 175), and the timer 24 is started (# 180).
Return to # 125.

When the value of the flag is 1, the elapsed time T from the time when the rotation amount becomes equal to or more than the predetermined amount is obtained from the output of the timer 24, and is compared with the predetermined time T0 (# 18).
5). The predetermined time T0 is set to 2 seconds as described above. When the elapsed time T is less than the predetermined time T0, #
Return to 125. If the elapsed time T is equal to or longer than the predetermined time T0, the process returns to step # 105 to perform an initialization process.

According to the above processing, when the rotation amount of the head exceeds the predetermined amount for a predetermined period of time, the reference direction is updated (# 105) and the virtual image is reset to the reference position (# 11).
0) is performed, and otherwise, the change of the virtual image position according to the detected rotation amount is continued. The observer can intentionally change the direction of the head largely and keep the state for a short time to update the reference direction and reset the virtual image to the reference position.

The predetermined time T0 may be set to 0 second, and when the amount of rotation of the head exceeds the predetermined amount, the reference direction may be updated immediately and the virtual image may be reset to the reference position. In this case, the timer 24 and the flag become unnecessary, and the processing flow is simplified. However, when the predetermined amounts RH0 and RV0 in the horizontal direction and the vertical direction are small, resetting of the virtual image to the reference position frequently occurs, and image observation may be troublesome. The predetermined amounts RH0, RV0 as in this embodiment
Is set to about 30 ° and 21 °, it is possible to avoid such unwanted resetting of the virtual image position.

FIG. 5 shows an optical configuration of a second embodiment of the HMD of the present invention. The HMD 2 has a pair of left and right LCDs 5.
1L, 51R, and a pair of left and right fixed lenses 53L, 53R
This is a configuration in which the movable lens is removed from the HMD 1 of the first embodiment. The fixed lenses 53L and 53R independently constitute left and right eyepiece optical systems. Therefore, the optical axes AXL and AXR of the eyepiece optical system are fixed.

As the LCDs 51L and 51R, the L of the HMD1 is used.
A CD having a larger display range than the CDs 11L and 11R is used, and the ratio of the length and width is 2: 3. The viewing angle is 120 ° in the horizontal direction and 84 ° in the vertical direction.
The display ranges of L and 51R are set so as to be exactly within the field of view. That is, the angle of view of the LCDs 51L and 51R is 120 ° in the horizontal direction and 84 ° in the vertical direction.

In the HMD 2, the LCDs 51L, 51R
Is not displayed in the entire display range, but an image is displayed in a part of the display range, and the position of the image in the display range is changed according to the detected orientation of the observer's head. The relative position of the virtual image with respect to the eyes EL and ER of the observer changes due to the change of the display position. The display position of the image is changed so as to cancel the change in the direction of the head, thereby preventing the absolute position of the virtual image from changing.

FIG. 6 shows an outline of a configuration from the detection of the orientation of the head to the change of the virtual image position. The HMD 2 includes angular velocity sensors 61H and 61H for detecting the rotational speed of the head.
V, and integrating circuits 62H, 6 for integrating the detected angular velocity
It has 2V. These configurations and functions are described in
It is the same as that of MD1. Outputs of the integration circuits 62H and 62V are given to a microcomputer 63 for controlling a display position of a video on the LCDs 51L and 51R.

The LCDs 51L and 51R are LCD
It is driven by drive circuits 71L and 71R. Also in the HMD 2 of the present embodiment, video signals are individually supplied to the left and right LCD drive circuits 71L and 71R in order to enable display of stereoscopic video. In addition, in order to change the image display position on the LCDs 51L and 51R according to the detected head orientation, the video signals supplied to the LCD drive circuits 71L and 71R are changed according to the head orientation.

For this purpose, two types of image memories and A / D
A converter is provided for each of the left and right video signals. The left video signal is A / D converter 65L, 1st
Is supplied to the LCD drive circuit 71L through the memory 66L and the second memory 68L, and the right video signal is supplied to the A / D converter 65R, the first memory 66R, and the second memory 68L.
It is supplied to the LCD drive circuit 71R via R. The A / D converters 65L and 65R digitize the video signal provided as an analog signal and store it in the memories 66L and 66R.

Each of the memories 66L and 66R has a storage capacity corresponding to a video signal for one field, and stores a video signal for one field using the entire area. Memory 6
8L and 68R have a storage capacity equivalent to four times the video signal for one field, and use one-fourth of the entire area.
The video signal of the field is stored. The storage in the memories 68L and 68R is controlled by the microcomputer 63 via the memory controllers 67L and 67R for managing the respective addresses.

The memories 66L, 66R and the memory 68L,
68R, the storage position of the video signal in the LCD 51L,
FIG. 7 shows the relationship between the image display positions in 1R. The entire storage area of the memories 68L and 68R corresponds to the entire display range of the LCDs 51L and 51R, and the image display positions on the LCDs 51L and 51R are determined by the image signal storage positions of the memories 68L and 68R. The angle of view of the displayed image is 6 in the horizontal direction.
0 ° and the vertical direction is 42 °, which is の of the angle of view of the entire display range of the LCDs 51L and 51R.

The microcomputer 63 includes an integrating circuit 6
The horizontal and vertical rotation amounts of the observer's head are calculated from the outputs of 2H and 62V, and the storage positions of the video signals in the memories 66L and 66R in the memories 68L and 68R are changed according to the calculated rotation amounts. Let it. Specifically, when the amount of rotation in the horizontal and vertical directions is 0, that is, when the head is facing the reference direction, as shown by the arrow A, the LCD 51
The video signal is stored in the storage area corresponding to the center of L, 51R. Further, for example, when the head is rotating to the lower right from the reference direction, as shown by the arrow B, the LCD 51
The video signal is stored in the storage area corresponding to the upper left of L and 51R. The storage position is calculated by a simple trigonometric function using only the rotation amount as a variable.

When the storage position is controlled in this way, the position of the virtual image appearing in the visual field can be determined in the same manner as in the first embodiment.
It becomes as shown in.

Since the horizontal and vertical angles of view of the LCDs 51L and 51R are 120 ° and 84 °, respectively, the amount of rotation of the head from the reference direction is within ± 30 ° in the horizontal direction and ± 21 ° in the vertical direction. If not, the memory 68
L and 68R can be stored without losing the video signal. Although the memories 66L, 66R, 68L, 68R are actually one-dimensional arrays, they can be handled as two-dimensional arrays as shown in the figure by address management.

Also in the HMD 2 of this embodiment, the virtual image position and the reference direction are reset when the state in which the head is rotated by a predetermined amount or more from the reference direction continues for a predetermined time. Specifically, a predetermined amount of 30 ° in the horizontal direction and 21 ° in the vertical direction at which all the video signals cannot be stored in the memories 68L and 68R and a part of the video is not displayed is set to a predetermined amount, and the predetermined time is 2 seconds. And In order to automatically reset the virtual image position and the reference direction, the microcomputer 6
3 is provided with a timer 64, and a reset switch 69 for manual resetting by the observer's intention.

FIG. 8 shows the flow of processing relating to the change of the virtual image position in the HMD 2. First, the integration circuits 62H and 62V
Is initialized to set the amount of head rotation to 0 (step # 20).
5) The image is displayed at the center of the LCDs 51L and 51R, and the left and right virtual images are set as reference positions (# 210). Next, the value of the flag is set to 0 (# 215), and the timer 24 is stopped (# 220). The functions of these flags and timers are the same as those in the processing of the first embodiment shown in FIG.

After the completion of the initialization processing, the operation of the reset switch 69 is determined (# 225). When the reset switch 69 is ON, the flow returns to # 205 to perform the initialization processing. When the reset switch 69 is off, the outputs of the angular velocity sensors 61H and 61V are integrated by the integration circuits 62H and 62V (# 230), and the horizontal rotation amount RH and the vertical rotation amount RV of the head are determined from the integration results. Calculate (# 23
5). Next, it is determined whether or not the calculated rotation amounts RH and RV are equal to or larger than predetermined amounts RH0 (30 °) and RV0 (21 °), respectively (# 240).

If the horizontal rotation amount RH is less than the predetermined amount RH0 and the vertical rotation amount RV is less than the predetermined amount RV0, an image position to be displayed on the LCDs 51L and 51R is calculated (# 245). Change the write address to the 68L, 68R in accordance with the calculated display position (#
250), change the display position of the video. Thereby, the relative position of the virtual image with respect to the eye changes. Next, the flag setting is determined (# 255). When the value is 0, the process returns to # 225, and when the value is 1, the flag value is set to 0 (# 26).
0), the running timer 64 is stopped (# 26)
5) Return to # 225.

In the determination of # 240, when the horizontal rotation amount RH is equal to or more than the predetermined amount RH0, or when the vertical rotation amount RV is equal to or more than the predetermined amount RV0, the setting of the flag is determined (# 270). When the value of the flag is 0, the value of the flag is set to 1 (# 275), the timer 64 is started (# 280), and the process returns to # 225. When the value of the flag is 1, the elapsed time T from when the rotation amount becomes equal to or more than the predetermined amount is obtained from the output of the timer 64, and is compared with the predetermined time T0 (2 seconds) (# 285). When the elapsed time T is shorter than the predetermined time T0, the process returns to # 225, and when the elapsed time T is longer than the predetermined time T0, the process returns to # 205.

In the above process, when the amount of rotation of the head exceeds the predetermined amount for a predetermined time, the reference direction is updated (# 205) and the virtual image is reset to the reference position (# 210).
In other cases, the change of the virtual image position according to the detected amount of rotation is continued. The observer can update the reference direction and reset the virtual image to the reference position by largely changing the direction of the head and keeping the state for a short time.

In the HMD 2 according to the present embodiment, the size of the displayed image is halved in both the horizontal and vertical directions with respect to the size of the entire display range. Is not limited to this value, and the ratio between the horizontal direction and the vertical direction may be set to different values. However, the ratio of the storage capacities of the memories 68L and 68R to the memories 66L and 66R needs to be equal to or greater than the area ratio of the entire display range to the display video.

The angle of view of the entire display range is set to 12 in the horizontal direction.
Although it is set to 0 ° and the vertical direction to 84 ° to make it the same as the viewing angle, as long as the entire display range is within the field of view, the angle of view and the viewing angle of the entire display range may be different values. May be set to another value. The predetermined amounts RH0 and RV0 for determining whether or not to reset the reference direction and the virtual image position may be set arbitrarily regardless of the size of the displayed image or the entire display range. .

In addition to the two angular velocity sensors 61L and 61R for detecting the horizontal rotation and the vertical rotation, a third angular velocity sensor for detecting the inclination of the head in the left-right direction is provided. The video displayed on the LCDs 51L and 51R may be rotated according to the tilt. The virtual image can be fixed by canceling the inclination of the head, and the observer can observe the image in the same manner as when viewing a stationary object.

It is also possible to adopt a configuration in which the displayed image is directly observed without passing through the eyepiece optical system. The observer observes the real image instead of the virtual image, but by changing the display position, the relative position of the real image with respect to the eye can be changed. However, in this case, it becomes necessary to make the display element considerably large, and it becomes difficult to form the HMD in a small size and light weight.

In a configuration in which a display image is enlarged and observed by an eyepiece optical system as in the HMD 2 of the present embodiment, an eyepiece is required, but the display element does not need to be too large. Can be reduced in size and weight. Moreover, the distance from the eye to the virtual image can be set to be equal to or greater than the distance from the eye to the display element, and the diopter can be set arbitrarily, which is more suitable for the purpose of reducing eye fatigue. .

[0070]

According to the video display device of the first aspect,
When the direction of the observer's head changes, the virtual image can be moved so that the virtual image does not follow the change in the direction of the head. Therefore, by turning the head, the observer can observe an arbitrary area of the displayed image at a position that is easy to observe, such as directly in front. This eliminates the need to rotate the eyeball to change the direction of the line of sight to gaze at the desired area, thereby reducing eye fatigue. In addition, it is also possible to change the relative position of the virtual image with respect to the eyes in accordance with the slight movement of the head to finely move the virtual image, whereby the movement of the eyeballs when the head is stationary and image observation is performed, Eye fatigue is further reduced.

According to the image display device of the present invention, it is possible to change the position of the image observed by the observer, that is, the virtual image, without generating the image to be displayed by a special method.
For example, shooting and display are performed in parallel to change the shooting range according to the direction of the head, and a wide range of images are recorded in advance and a part of the image is displayed according to the direction of the head. No complicated processing is required. Therefore, it is possible to simplify the entire configuration including a video generation device such as a camera for photographing.

Further, even when only a fixed video signal is given and a video cannot be changed in accordance with the direction of the head as in a television, the position of the image to be observed can be changed. There are no restrictions. Further, even if the displacement of the eyepiece optical system is slight, the course of the image light changes greatly and the position of the virtual image with respect to the eye changes greatly, so that it is possible to cope with a large change in the direction of the head.

The image display device according to the third aspect also has no restriction on the method of generating an image, and therefore its use is not limited. Further, it is only necessary to provide a circuit for changing a display position of an image, and a mechanical drive mechanism is not required. Therefore, the apparatus can be made small and lightweight. In addition, since the display position is changed at a very high speed by the electric processing, it is possible to quickly respond to the movement of the head.

In the image display device according to the fourth aspect, the absolute position of the virtual image does not change at all when the observer turns his / her head, so that the observer operates in exactly the same natural manner as when looking at a stationary object. To observe the image. Since the micromotion generated when the head is stationary appears as a micromotion of the virtual image, image observation when the head is stationary is also natural. Therefore, no burden is imposed on the eyes, and eye fatigue can be reduced.

According to the video display device of the fifth aspect, when the amount of change in the direction of the head becomes so large that the image cannot be observed, the image can be reset to a predetermined position. Images can always be observed regardless of the orientation of the head. Also, the position of the virtual image changes according to the direction of the head only when the amount of change in the direction of the head is within a certain range, and when the amount of change in the direction of the head exceeds a certain range, the virtual image is returned to the predetermined position. Since it is set, it is not necessary to turn the head in a certain direction to view the image at a certain position. Therefore, it is possible to observe an image in a free posture, and it is possible to reduce not only eye fatigue but also whole body fatigue.

[Brief description of the drawings]

FIG. 1 is a diagram showing an optical configuration of an HMD according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a circuit configuration from detection of a head direction to change of a virtual image position in the HMD according to the first embodiment;

FIG. 3 is a diagram showing a configuration for moving a movable lens of the HMD according to the first embodiment and detecting a moving amount thereof.

FIG. 4 is a flowchart illustrating a flow of a process of changing a virtual image position in the HMD according to the first embodiment.

FIG. 5 is a diagram illustrating an optical configuration of an HMD according to a second embodiment of the present invention.

FIG. 6 is a block diagram showing a circuit configuration from detection of a head direction to change of a virtual image position in the HMD according to the second embodiment.

FIG. 7 is a diagram illustrating a relationship between a storage position of a video signal in an image memory and a display position of a video on an LCD in the HMD according to the second embodiment.

FIG. 8 is a flowchart illustrating a flow of a process of changing a virtual image position in the HMD according to the second embodiment.

FIG. 9 is a diagram illustrating an example of a positional relationship between a visual field and a virtual image in the visual field in the HMD according to the first and second embodiments.

[Explanation of symbols]

 1 HMD 11L, 11R LCD (display means) 12L, 12R Movable lens (eyepiece optical system) 13L, 13R Fixed lens (eyepiece optical system) 21H, 21V Angular velocity sensor (detection means) 22H, 22V Integration circuit (detection means) 23 micro Computer 24 Timer 25L, 25R Lens drive circuit (change means) 26L, 26R Lens movement amount detection circuit 27H, 27V Electromagnetic actuator 28H, 28V Electromagnetic sensor 29 Reset switch 31L, 31R LCD drive circuit 2 HMD 51L, 51R LCD (display means) 53L, 53R Fixed lens (eyepiece optical system) 61H, 61V Angular velocity sensor (detection means) 62H, 62V Integration circuit (detection means) 63 Microcomputer 64 Timer 65L, 65R A / D converter 66L, 66R Image memory 67L, 67R Memory controller Roller 68L, 68R Image memory (change means) 69 Reset switch 71L, 71R LCD drive circuit (change means)

Claims (5)

[Claims] 1. A head-mounted image display device comprising a display means for displaying an image and an eyepiece optical system, wherein a virtual image of the image displayed on the display means is provided to an observer's eye by the eyepiece optical system. Detecting means for detecting the direction of the head of the observer, and changing means for changing the position of the virtual image with respect to the observer according to the direction of the head of the observer detected by the detecting means. Characteristic video display device. 2. The image display device according to claim 1, wherein the changing unit changes the position of the virtual image by displacing the eyepiece optical system. 3. The video display device according to claim 1, wherein the changing unit changes the position of the virtual image by changing a display position of the video on the display unit. 4. The detecting means detects the direction and amount of deviation of the orientation of the observer's head from a reference direction, and the changing means determines the position of the virtual image in a direction opposite to the direction of the detected deviation. 2. The image display device according to claim 1, wherein the image display device is moved by an amount corresponding to the detected deviation. 5. The detecting means detects an amount of deviation of the orientation of the observer's head from a reference direction, and when the amount of deviation detected by the detecting means is less than a predetermined amount, the changing means Changes the position of the virtual image according to the detected orientation of the observer's head, and when the amount of displacement detected by the detection unit is equal to or greater than the predetermined amount, the change unit changes the position of the virtual image. The image display device according to claim 1, wherein the image display device is set at a predetermined position, and the detection unit sets the detected orientation of the observer's head as a reference orientation.