JP2010145561A - Head mount display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure a laterally wide external visual field while adjusting the eye width by a small structure. <P>SOLUTION: Each optical pupil E<SB>R</SB>/E<SB>L</SB>of image display units 1R/1L includes an obliquely flattened shape in which the long axial direction is inclined at an angle smaller than 90° to the eye width direction within a vertical section facing a face including the center of each optical pupil E<SB>R</SB>/E<SB>L</SB>. Thus, an image display 1 is vertically moved by a drive mechanism 9, whereby the pupils of an observer are located in positions differed in the eye width direction within the vertical section to observe image, and the eye width adjustment is easily performed. Since the drive mechanism 9 drives both the right and left optical units in the same direction (upward or downward), the eye width adjustment mechanism is reduced in size, compared with a conventional structure adapted to laterally drive the units in mutually opposite directions. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a head mounted display (hereinafter also referred to as an HMD) for observing an image by positioning an image display device in front of an observer's eyes.

  In an HMD that observes images with both eyes, a virtual image of an image displayed on each display unit is observed by positioning the viewer's eyes at the position of each optical pupil formed by each display unit. Can do. At this time, the eye width of the observer varies from observer to observer, and the size of each optical pupil is limited. Therefore, in order for a plurality of observers with different eye widths to observe images well, It is necessary to adjust the position of the eye width direction. In this regard, for example, in the apparatus of Patent Document 1, the eye width adjustment is performed by providing an eye width adjusting mechanism that moves the positions of the left and right eyepieces in the eye width direction. For example, in the apparatus of Patent Document 2, the eye width adjustment is performed by moving the left and right display units in the eye width direction by the eye width adjusting mechanism.

JP-A-5-276467 JP 2003-307701 A

  However, in the conventional eye width adjustment mechanism, the movement direction of the left and right optical systems or units is the eye width direction, and the left and right directions are opposite to each other. In order to ensure a large amount of movement, the eye width adjustment mechanism must be enlarged, and the entire apparatus is enlarged. Moreover, if the eye width adjustment mechanism arrange | positioned between both eyes like patent document 2 is large, it will become impossible to ensure the external field visual field of the left-right direction widely.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to adjust the eye width with a small configuration and to ensure a wide external field of view in the left-right direction. It is to provide a small HMD.

  The HMD of the present invention includes a video display device and support means for supporting the video display device in front of an observer's eye, and the video display device displays a video image and video light from the display device. A head-mounted display including a reflective optical element that reflects the light to the optical pupil and the optical pupil is in a vertical section facing the face including the center of the optical pupil, the major axis direction being the width direction of the eye And the support means includes a drive means for moving the video display device in a direction perpendicular to the eye width direction within the plane. It is characterized by.

In the HMD of the present invention, when the relative angle between the major axis direction of the optical pupil and the eye width direction is θ,
0 ° <θ <45 °
It is desirable that

  In the HMD of the present invention, the driving means includes a nose pad that contacts the observer's nose and a nose pad driving unit that moves the nose pad up and down (perpendicular to the eye width direction). Also good.

  In the HMD of the present invention, the reflection optical element may be a volume phase type reflection type hologram optical element.

In the HMD of the present invention, an axis optically connecting the center of the display surface of the display element and the center of the optical pupil is an optical axis, and the optical axis incident on the hologram optical element from the display element side is When the surface including the optical axis emitted to the optical pupil side is an optical axis incident surface, when the relative angle between the vertical plane perpendicular to the eye width direction and the optical axis incident surface is α,
0 ° <α <90 °
It may be.

In the HMD of the present invention,
0 ° <α <45 °
It is desirable that

  In the HMD of the present invention, the image light from the display element may be light including at least one of red, green, and blue wavelength regions.

  In the HMD of the present invention, the video display device further includes an optical member that totally reflects and guides the video light from the display element, and the hologram optical element guides the inside of the optical member. The image light from the display element that is illuminated may be diffracted and reflected and guided to the optical pupil.

  In the HMD of the present invention, the hologram optical element has an axially asymmetric positive optical power, and may constitute at least part of an eyepiece optical system that guides image light from the display element to an optical pupil. Good.

  In the HMD of the present invention, the video display device includes a left-eye display unit and a right-eye display unit corresponding to the left and right eyes of the observer, and both the display units are each configured to display the display. It is desirable that the optical pupils of the display units are symmetrical with respect to a plane perpendicular to the eye width direction.

  According to the present invention, since the optical pupil has an obliquely flat shape, the image display device is moved vertically by the driving means (in the vertical section facing the face including the center of the optical pupil, perpendicular to the eye width direction (left-right direction)). By moving the image in the direction), it is possible to observe the video with the observer's pupil positioned at different positions in the eye width direction. That is, the eye width in the left-right direction can be adjusted by moving the apparatus up and down, and the eye width can be easily adjusted. Further, for example, even when a display unit is provided for both eyes, it can be configured to drive in the same direction (upward or downward) on both the left and right sides, so that the drive means can be reduced in size compared to the left and right drive. Therefore, the eye width can be adjusted with a small configuration, and the apparatus can be miniaturized.

  In addition, since the driving means of the present invention can be downsized as described above compared to the conventional left-right driving eye width adjustment mechanism, even if the driving means is arranged between both eyes, the left-right field of view is the driving means. A wide external field of view can be secured in the left-right direction without being blocked.

  An embodiment of the present invention will be described below with reference to the drawings.

(About video display device)
First, a video display device provided in the HMD of this embodiment will be described. FIG. 2 is a cross-sectional view showing a schematic configuration of the video display device 1. The video display device 1 includes a left-eye video display unit 1L (left-eye display unit) corresponding to the left and right eyes of an observer, and a right-eye video display unit 1R (right-eye display unit). Has been. Each of the video display units 1R and 1L includes a video display unit 11 and an eyepiece optical system 21. The video display unit 11 includes a light source 12, a unidirectional diffuser plate 13, a condenser lens 14, and an LCD 15.

  Here, for convenience of explanation below, directions are defined as follows. First, an axis that optically connects the center of the display surface of the LCD 15 and the center of the optical pupil E (exit pupil, observation pupil) formed by the eyepiece optical system 21 is an optical axis. Then, a surface including an optical axis incident from the LCD 15 side and an optical axis emitted from the optical pupil E side with respect to a hologram optical element (HOE) constituting an optical element 24 described later of the eyepiece optical system 21 Axis incidence surface. At this time, the direction of the optical axis emitted from the HOE to the optical pupil E side is defined as the Z direction, and the direction perpendicular to the Z direction within the optical axis incident surface is defined as the Y direction. A direction perpendicular to the Y direction and the Z direction (that is, a direction perpendicular to the optical axis incident surface) is defined as an X direction.

  In the present embodiment, as will be described later, the video display units 1R and 1L are arranged to be inclined with respect to a vertical plane perpendicular to the viewer's eye width direction. Is at a predetermined angle with the vertical plane. Accordingly, when the observer wears the HMD, the eye width direction forms a predetermined angle with the X direction, and the vertical direction perpendicular to the eye width direction forms a predetermined angle with the Y direction.

  The light source 12 is configured by an integrated LED of red (R), green (G), and blue (B) that emits light in three wavelength bands whose center wavelengths are 635 nm, 520 nm, and 465 nm, for example. The RGB light emitting units of the light source 12 are arranged side by side in the X direction.

  The unidirectional diffuser plate 13 diffuses illumination light from the light source 12, but the degree of diffusion differs depending on the direction. More specifically, the unidirectional diffusion plate 13 diffuses incident light by about 40 ° in the direction (X direction) in which the RGB light emitting portions of the light source 12 are arranged, and in the direction perpendicular thereto, the incident light is reduced by about 40 °. Spread 0.2 °. The condenser lens 14 is an illumination optical system that condenses the light diffused by the unidirectional diffusion plate 13. The condenser lens 14 is disposed so that the diffused light efficiently forms the optical pupil E.

  The LCD 15 is a display element that displays an image by modulating light from the light source 12 on a pixel-by-pixel basis based on the image signal. For example, the LCD 15 includes a transmissive liquid crystal display element. In the present embodiment, since the video display units 1R and 1L are inclined with respect to the vertical plane, the top and bottom and the left and right of the video (virtual image) observed at the position of each optical pupil E are between the video display units 1R and 1L. In order to make them the same, each LCD 15 is arranged so as to rotate around the center of the display surface.

  On the other hand, the eyepiece optical system 21 guides the image light from the LCD 15 to the optical pupil E, and transmits the external light to the optical pupil E so that the external image is displayed together with the virtual image of the display image at the position of the optical pupil. Let them see through. The eyepiece optical system 21 includes a cemented prism (a cemented optical member), and configures a telecentric optical system. Specifically, the eyepiece optical system 21 is formed by joining an eyepiece prism 22 and a deflection prism 23, which are optical members, with an optical element 24 interposed therebetween.

  The eyepiece prism 22 and the deflection prism 23 are joined with an adhesive. The eyepiece prism 22 is formed in a shape in which the lower end portion of the parallel plate is wedge-shaped and the upper end portion is thickened, and guides the image light from the LCD 15 by totally reflecting it internally. The eyepiece prism 22 has surfaces 22a, 22b, and 22c. The surface 22a is an incident surface on which image light from the image display unit 11 is incident, and the surfaces 22b and 22c are surfaces facing each other. Among these, the surface 22b is a total reflection surface and an emission surface.

  The deflection prism 23 is configured to be a substantially parallel flat plate integrally with the eyepiece prism 22 by forming the upper end portion of the parallel plate along the lower end portion of the eyepiece prism 22. When the deflecting prism 23 is not joined to the eyepiece prism 22, the external light is refracted when it passes through the wedge-shaped lower end of the eyepiece prism 22, so that the external field image observed through the eyepiece prism 22 is distorted. However, the deflection prism 23 is joined to the eyepiece prism 22 to form an integral substantially parallel plate, whereby the deflection when the external light passes through the wedge-shaped lower end of the eyepiece prism 22 is canceled by the deflection prism 23. Can do. As a result, it is possible to prevent distortion in the external image observed through the see-through.

  The optical element 24 is a reflective optical element that reflects the image light from the LCD 15 guided inside the eyepiece prism 22 and guides it to the optical pupil E, and is composed of, for example, a volume phase type reflective HOE. This HOE diffracts light in three wavelength bands, for example, 465 ± 10 nm, 520 ± 10 nm, and 635 ± 10 nm, which are incident at a specific incident angle. The optical element 24 is attached to the inclined surface at the lower end of the eyepiece prism 22, and as a result, is sandwiched between the eyepiece prism 22 and the deflection prism 23. By forming the HOE between the two transparent members (the eyepiece prism 22 and the deflection prism 23), the HOE does not come into contact with the outside air, so that the optical performance can be kept stable.

  With such a configuration of the video display units 1R and 1L, the light emitted from the light source 12 of the video display unit 11 is diffused by the unidirectional diffusion plate 13, condensed by the condenser lens 14, and incident on the LCD 15. To do. The light incident on the LCD 15 is modulated for each pixel based on the video signal and is emitted as video light. At this time, the image itself is displayed on the LCD 15.

  The image light from the LCD 15 enters the eyepiece prism 22 of the eyepiece optical system 21 from its upper end surface (surface 22a), is totally reflected a plurality of times by the two opposing surfaces 22b and 22c, and enters the optical element 24. To do. The light incident on the optical element 24 is reflected there, exits through the surface 22b, and reaches the optical pupil E. At the position of the optical pupil E, the observer can observe an enlarged virtual image of the image displayed on the LCD 15.

  On the other hand, the eyepiece prism 22, the deflection prism 23, and the optical element 24 transmit almost all the external light, so that the observer can observe the external image. Therefore, the virtual image of the image displayed on the LCD 15 is observed while overlapping with a part of the external image. From the above, it can be said that the optical element 24 functions as a combiner that guides the video (video light) and the external image (external light) provided from the video display unit 11 simultaneously to the eyes of the observer.

  As described above, the eyepiece optical system 21 includes the optical element 24 composed of a volume phase type and a reflection type HOE. Volume phase type reflection type HOE has high diffraction efficiency, and the half-value wavelength width of the diffraction efficiency peak is narrow. Therefore, a bright image can be observed by using such a HOE and adopting a configuration in which the image light from the LCD 15 is diffracted and reflected by the HOE and guided to the optical pupil E. Moreover, since the transmittance of external light is increased, a bright external image can be observed.

  In addition, since the video light is guided using total reflection in the eyepiece prism 22, the thickness can be reduced to the same level as that of a normal spectacle lens (for example, about 3 mm), and the eyepiece prism 22 can be made compact. While being able to be lightweight, the transmittance of external light becomes high and the external environment can be observed well. Further, the LCD 15 can be arranged on one end side of the eyepiece optical system 21, that is, it can be arranged around the visual field, and a wide external field viewing angle can be secured.

  Further, the HOE has an axially asymmetric positive optical power for enlarging the image displayed on the LCD 15 and constitutes at least a part of the eyepiece optical system 21, so that the eyepiece optical system 21 can be reduced in size. While configuring, it is possible to increase the degree of freedom of arrangement of each optical member constituting the apparatus, to reduce the size and weight of the apparatus, and to observe an image with good aberration correction.

  Further, as described above, since the optical element 24 is composed of a volume phase type reflection type HOE that diffracts only light having a specific wavelength at a specific incident angle, the image light from the LCD 15 is deflected by the eyepiece prism 22. The external light transmitted through the prism 23 and the optical element 24 is not affected. Therefore, the observer can observe the external image clearly and normally through the eyepiece prism 22, the deflection prism 23, and the optical element 24 while observing the virtual image of the display image on the LCD 15 through the optical element 24. it can.

  The optical element 24 embedded in the reflection surface of the eyepiece optical system 21 may be a half mirror, a multilayer film, or the like, but it is more preferable to use the above-described volume phase type reflection type HOE. Since the volume phase type and reflection type HOE have both high wavelength selectivity and angle selectivity, they have a diffractive reflection effect only on light in a limited wavelength range. HOE can be effectively used as a combiner element that synthesizes transmitted light of other wavelengths.

  As a hologram photosensitive material for producing HOE, a photopolymer, a silver salt material, gelatin dichromate, or the like can be used. Among them, it is desirable to use a photopolymer that can be easily manufactured by a dry process.

(About the shape of the optical pupil)
In the present embodiment, the optical pupils E of the video display units 1R and 1L each have an obliquely flat shape in a vertical cross section that faces the viewer's face, including the center of each optical pupil E. . Hereinafter, the reason why such a shape is obtained will be described. First, the reason why the optical pupil E has a flat shape will be described.

  FIG. 3A is an explanatory diagram schematically showing the optical path of the reproduction light beam (image light beam) in the optical axis incident plane, and FIG. 3B is the optical pupil E during reproduction (image observation). It is explanatory drawing which shows the shape of this. In FIGS. 3A and 3B, it is assumed that the optical axis incident surface and the vertical surface perpendicular to the eye width direction coincide with each other. Therefore, the vertical plane includes the optical axis connecting the center of the optical element 24 (HOE) and the center of the optical pupil E.

  An optical element 24 made of HOE is disposed at an angle φ (°) from the vertical direction on the optical axis incident surface, and image light is incident on the optical element 24 from above, and the optical element 24 moves in the pupil direction. When reflected, the optical pupil E has an oblong shape that is long in the direction perpendicular to the optical axis incident surface (left-right direction). This is because the characteristics of the HOE (wavelength selectivity and angle selectivity) and the wavelength range of the image light are limited. More details are as follows.

  FIG. 4A is an explanatory view schematically showing an optical path of an exposure light beam when exposing the hologram photosensitive material 24a for producing a HOE as a combiner, and FIG. 4B is produced by the above exposure. It is explanatory drawing which shows typically the optical path of the reproduction | regeneration light beam (video light beam) at the time of reproducing | regenerating using the made HOE (optical element 24). As shown in FIG. 4A, the optical element 24 includes the exposure light beam 1 (wavelength λa) in the same direction as the direction from the optical element 24 toward the display element (LCD 15), and the direction from the optical pupil E toward the optical element 24. Is produced by exposing the hologram photosensitive material 24a using the exposure light beam 2 (wavelength λa) in the same direction as in FIG.

  On the other hand, at the time of reproduction, as shown in FIG. 4B, the reproduction light beam (video light beam) from the display element opposite to the exposure light beam 1 is incident on the optical element 24 and is diffracted and reflected in the direction of the optical pupil E. The Here, when the light at the center of the screen of the display element is considered, light having the same wavelength as the exposure light beam 2 is diffracted and reflected by the optical element 24 at the center of the optical pupil E equal to the point light source position of the exposure light beam 2. However, the angle difference with the exposure light beam 2 becomes large at a position shifted in the vertical direction from the center of the optical pupil E, and the wavelength of the light incident upon being diffracted and reflected by the optical element 24 is different from that of the exposure light beam 2.

  In other words, for image light that is incident on a position that is vertically displaced from the center of the pupil in a vertical cross section that faces the face including the center of the optical pupil E, the exit direction of the image light from the optical element 24 is the exposure light beam 2. The angle difference in the optical axis incident plane deviating from the incident direction is large, and the wavelength shift becomes large. On the other hand, with respect to the image light incident at a position shifted in the left-right direction from the pupil center in the vertical cross section, the optical axis incidence where the emission direction of the image light from the optical element 24 deviates from the incident direction of the exposure light beam 2. The angle difference in the plane is small and the wavelength shift is small.

And since the image light is generally composed of light in a limited wavelength range, the vertical direction in which the angle difference that the emission direction of the image light deviates from the incident direction of the exposure light beam is increased due to the influence of the wavelength range. However, the optical pupil E becomes smaller than that in the left-right direction, resulting in a horizontally elongated pupil shape. Note that the image light in the limited wavelength range can be obtained by the following (1) or (2) or the like, and by combining the image light thus obtained and the optical element 24, an elongated optical pupil is obtained. E can be obtained.
(1) A light source having a relatively narrow wavelength range such as an RGB LED is used as the light source 12.
(2) Even when the light source 12 having a wide wavelength range such as a white LED is used, a liquid crystal display element having a color filter is used as the LCD 15 to limit the transmission wavelength range of the RGB color filter.
Note that the image light only needs to be composed of light in a limited wavelength range, and may be composed only of light in any one of the RGB wavelength ranges. That is, it can be said that the image light from the LCD 15 may be light including at least one of the RGB wavelength ranges.

  The fact that the optical pupil E has a horizontally long shape can be understood more easily by referring to the following specific calculation model.

<Calculation model conditions>
-HOE which comprises the optical element 24 is a plane.
The HOE is arranged so as to be inclined by 30 degrees with respect to the vertical direction within the optical axis incident surface.
The HOE is manufactured using parallel light incident at an incident angle of 30 degrees with respect to the normal of the HOE and parallel light reflected at a reflection angle of −30 degrees with respect to the normal.
The distance between the center of the HOE and the optical pupil E is 15 mm.
The exposure laser wavelength when producing the HOE is Kr ⁺ 647.1 nm.
The shrinkage of the hologram photosensitive material is 2% in the thickness direction.
・ HOE diffraction half width is not considered.
Calculate the incident wavelength at positions shifted by ± 1.5 mm in the vertical direction from the center of the optical pupil E.
The reproduction light source is an RGB three-color / one-chip LED. For example, the emission peak wavelength of R is 635 nm and the half-value intensity is 20 nm.

  FIG. 5A is an explanatory diagram showing diffraction peak wavelengths of light rays incident on the center of the optical pupil E and the upper and lower ends of ± 1.5 mm therefrom, and FIG. 5B shows the intensity distribution of the reproduction light source. It is explanatory drawing shown. Under the above calculation model conditions, as shown in FIG. 5A, the wavelength of the image light beam incident on the center of the optical pupil E is 635 nm, and the light beam is incident on a position ± 1.5 mm above and below the center of the optical pupil E. The wavelengths of the image rays are 665 nm and 593 nm, respectively. Further, under the above model conditions, the half-value wavelength width of the emission intensity is 625 to 645 nm for the R illumination light shown in FIG. That is, the half-value wavelength width of the R illumination light is narrower than the wavelength range of 593 to 665 nm necessary for forming the optical pupil E of ± 1.5 mm above and below. Therefore, the vertical size of the optical pupil E is limited to 3 mm or less. On the other hand, since the difference in the incident angle of the image light is small in the left-right direction of the optical pupil E, a pupil size sufficiently larger than 3 mm (for example, 8 mm) can be secured. As a result, the optical pupil E has a horizontally long flat shape. It becomes.

  In order to make each optical pupil E of the video display units 1R and 1L have an oblique flat shape, the video display units 1R and 1L may be rotated. FIG. 6 shows a front view before and after rotation of the video display unit 1L of the present embodiment and a schematic explanatory view of a pupil shape. By tilting the optical axis incident surface Q of the image display unit 1L by an angle α smaller than 90 degrees with respect to the vertical plane P perpendicular to the eye width direction, a horizontally long optical pupil E corresponding to the left eye of the observer. Is an obliquely flat shape in which the major axis direction is inclined by an angle θ (= α) with respect to the eye width direction. Similarly, by tilting the optical axis incident surface of the video display unit 1R by an angle α smaller than 90 degrees with respect to the vertical plane, the horizontally long optical pupil corresponding to the right eye of the observer has the long axis direction of the eye. An oblique flat shape inclined by an angle θ (= α) with respect to the width direction is obtained.

At this time, from the rotation direction of the optical axis incident surface of one video display unit (for example, video display unit 1R) from the vertical plane and from the vertical plane of the optical axis incident surface of the other video display unit (for example, video display unit 1L). By reversing the rotation direction, the optical pupils E of the video display units 1R and 1L are symmetrical with respect to the vertical plane P ₀ (see FIG. 1C) perpendicular to the eye width direction. . In this embodiment, assuming that the optical pupils of the video display units 1R and 1L are E _R and E _L , respectively, as shown in FIG. 7, the interval between the upper ends of the optical pupils E _R and E _L is the interval between the lower ends. The video display units 1R and 1L are arranged so as to be rotated in opposite directions so as to be narrower. Thereby, it can be easily avoided that the video display units 11 of the video display units 1R and 1L are too close to each other and interfere with each other.

If the video display units 11 do not interfere with each other, the video display units 1R and 1L are moved in opposite directions so that the distance between the upper ends of the optical pupils E _R and E _L is wider than the distance between the lower ends. You may arrange | position by rotating.

As described above, the relative angle between the vertical plane perpendicular to the eye width direction and the optical axis incident surface of the HOE is α (°).
0 ° <α <90 °
By satisfying the above, it becomes possible to easily form an obliquely flat optical pupil E by the wavelength selectivity of the HOE and the wavelength limitation of the image light. In particular,
0 ° <α <45 °
In this case, an oblique optical pupil E that is long in the eye width direction can be formed. Therefore, when the video display device 1 to be described later moves in the vertical direction, a large eye in the eye width direction with a small amount of movement in the vertical direction. The width adjustment amount can be taken.

  Further, the image light from the LCD 15 is light including at least one of the RGB wavelength ranges, and the wavelength range of the image light is limited. Therefore, such image light is transmitted through the HOE having wavelength selectivity. By guiding to the optical pupil E, the shape of the optical pupil E can be surely flattened.

  In the present embodiment, the optical pupil E has a flattened elliptical shape. However, such a shape can concentrate light rays in a necessary region as compared with a rectangular shape, for example. Light utilization efficiency is increased, and a bright image can be observed at the position of the optical pupil E.

(About HMD and eye width adjustment)
Next, an HMD provided with the above-described video display units 1R and 1L and eye width adjustment in the HMD will be described. FIG. 1A is a plan view showing a schematic configuration of the HMD according to the present embodiment, FIG. 1B is a front view of the HMD, and FIG. 1C is a side view of the HMD. is there. The HMD has a video display device 1 and support means 2 for supporting it, and as a whole has an appearance like general glasses. The HMD has a symmetrical shape in the left and right eye width directions.

  The video display device 1 allows an observer to observe an external image as a see-through, displays an image, and provides it to the observer as a virtual image, and includes the video display units 1R and 1L described above. In the video display units 1R and 1L shown in FIG. 1B, the portions corresponding to the right eye lens and the left eye lens of the spectacles are configured by bonding the eyepiece prism 22 and the deflection prism 23 (both see FIG. 2). Has been.

  The support means 2 supports the video display units 1R and 1L in front of the right and left eyes of the observer, and includes a bridge 3, a frame 4, a temple 5, a nose pad 6, a cable 7, And a nose pad drive unit 8. The frame 4, the temple 5, the nose pad 6, and the cable 7 are provided as a pair on the left and right sides. However, in order to distinguish between the left and right, the right frame 4R, the left frame 4L, the right temple 5R, the left temple 5L, the right It is expressed as a nose pad 6R, a left nose pad 6L, a right cable 7R, and a left cable 7L.

  The bridge 3 connects the video display units 1R and 1L and supports the nose pad drive unit 8. The right temple 5R is rotatably supported by the right frame 4R, and is connected to the video display unit 1R (on the side opposite to the connection side to the bridge 3) via the right frame 4R. Similarly, the left temple 5L is rotatably supported by the left frame 4L, and is connected to the video display unit 1L (on the side opposite to the connection side to the bridge 3) via the left frame 4L. . The nose pad 6 is a part that comes into contact with the nose of the observer and is supported by the nose pad driving unit 8.

  The cable 7 is a wiring for supplying an external signal (for example, a video signal, a control signal) and power to the video display units 1R and 1L. The right cable 7R is provided along the right temple 5R and the right frame 4R and connected to the video display unit 1R, and the left cable 7L is provided along the left temple 5L and the left frame 4L, and the video display unit. 1L is connected.

  The nose pad drive unit 8 moves the nose pad 6 in the vertical direction perpendicular to the eye width direction. Here, FIGS. 8A and 8B are cross-sectional views showing a schematic configuration of the nose pad drive unit 8, and show a state in which the nose pad 6 is positioned below and above, respectively. The nose pad drive unit 8 includes a rail 8a (guide member) extending in the vertical direction and a knob 8b (fixed portion). The nose pad 6 can be fixed at a predetermined position in the vertical direction by sliding the nose pad 6 in the vertical direction along the rail 8a and rotating the knob 8b. Thereby, the video display device 1 (video display units 1R and 1L) supported by the support means 2 can be moved in the vertical direction relative to the nose pads 6. Therefore, the above-described nose pad 6 and the nose pad drive unit 8 drive the image display device 1 in the vertical direction perpendicular to the eye width direction within the vertical cross section facing the face including the center of the optical pupil E. 9 (drive means) can be said to be configured. In addition, the sliding part with the rail 8a in the nose pad 6 is formed in the shape which prevents the nose pad 6 from coming off from the rail 8a.

When the observer uses the HMD, the right temple 5R and the left temple 5L are brought into contact with the right and left heads of the observer, and the nose pad 6 is put on the nose of the observer so as to wear general glasses. The HMD is attached to the observer's head. In this state, when the video is displayed on the video display units 1R and 1L, and the observer's right and left eyes are positioned at the positions of the optical pupils E _R and E _L , the viewer can view the video display units 1R and 1L. Each 1L display image can be observed as a virtual image with the right eye and the left eye, respectively, and an external image can be observed through the video display units 1R and 1L.

  Thus, since the video display apparatus 1 is supported in front of the observer's eyes by the support means 2, the observer can observe the video provided from the video display apparatus 1 in a hands-free manner. In addition, since the observation direction of the observer is determined in one direction, there is an advantage that the observer can easily search for a display image even in a dark environment.

Further, as described above, the optical pupils E _R and E _L of the video display units 1R and 1L are respectively in the long axis direction within the vertical cross section facing the face including the center of each of the optical pupils E _R and E _L. Has an oblique flat shape inclined at an angle θ (see FIG. 6) smaller than 90 degrees with respect to the eye width direction. Therefore, by moving the image display device 1 in the vertical direction by the drive mechanism 9, it is possible to observe the image by locating the observer's pupil at different positions in the eye width direction in the vertical section. That is, the eye width can be adjusted by moving the video display device 1 up and down.

For example, in FIG. 7, when the eye distance is D ₁ , D ₂ , D ₃ (unit is mm) and D ₁ > D ₂ > D ₃ , the observer with the eye distance D ₁ is for the right side. positions the right eye position R ₁ of the lower end of the optical pupil E _R, by positioning the left eye position L ₁ of the lower end of the optical pupil E _L for the left eye, it is possible to observe the image. Also, the observer's eye width distance D ₂ may be positioned to the right eye position R ₂ of the center of the optical pupil E _R for right and left eye positions L ₂ central optical pupil E _L for the left eye by positioning, image can be observed, the observer's eyes wide distance D ₃ is to position the right eye position R ₃ of the upper end of the optical pupil E _R for right, the optical pupil E for the left eye _An image can be observed by positioning the left eye at the position L ₃ at the upper end of L.

As described above, in the present embodiment, the optical pupil E (E _R · E _L ) has an obliquely flat shape in the vertical cross section. Therefore, by moving the video display device 1 in the vertical direction by the drive mechanism 9, It is possible to observe the video by locating the observer's pupil at different positions in the eye width direction, and the eye width can be easily adjusted. Further, since the drive mechanism 9 drives both the left and right optical units in the same direction (upward or downward), the eye width adjustment mechanism (drive mechanism) is compared with a conventional configuration that drives in the left-right direction and in the opposite directions. 9) can be reduced in size. Therefore, the eye width can be adjusted with a small configuration, and the entire apparatus can be downsized.

  Further, since the drive mechanism 9 can be reduced in size, a wide external field of view can be secured in the left-right direction even if the drive mechanism 9 is disposed between both eyes. Furthermore, since the drive mechanism 9 moves the left and right optical units simultaneously in the vertical direction, the drive mechanism 9 can be made smaller than in the case where the optical units are moved separately.

  Further, the relative angle θ between the major axis direction of the optical pupil E and the eye width direction in the vertical cross section shown in FIG. 6 is preferably 0 ° <θ <45 °. In this case, since the optical pupil E elongated in the eye width direction is an oblique pupil rotated by an angle of 45 ° or less, the adjustment amount of the left and right eye width can be increased with a small amount of movement in the vertical direction. Therefore, it is possible to further reduce the size of the drive mechanism 9 that is the eye width adjustment mechanism as compared with the case where a vertically long oblique pupil is formed as in the case of 45 ° <θ <90 °.

Further, as shown in FIG. 7, the optical pupils E _R and E _L of both the video display units 1R and 1L are formed symmetrically in the left-right direction, that is, a plane perpendicular to the eye width direction (see FIG. 1 (b) vertical plane P ₀ ). In this case, since the distance between the two optical pupils E _R and E _L becomes narrower (or wider) as it goes upward, the eye width adjustment can be performed by moving the image display device capable of binocular display in the vertical direction. Can be performed reliably.

  In addition, the nose pad 6 constituting the drive mechanism 9 is simply brought into contact with the observer's nose and can be easily downsized. The nose pad drive unit 8 can also be downsized by adopting the vertical drive of the nose pad 6. . That is, the nose pad drive unit 8 can drive the video display units 1R and 1L in the same direction (up or down) by simply sliding the nose pad 6 in the vertical direction. In addition, the nose pad drive unit 8 can be reduced in size as compared with the conventional eye width adjustment mechanism that drives in opposite directions. Therefore, a small drive mechanism 9 can be reliably realized by such a small nose pad 6 and nose pad drive unit 8. Furthermore, by adopting a configuration in which the eye width is adjusted by moving the nose pad 6 up and down, the pupil positions of both eyes of the observer can be adjusted at the same time, and the eye width can be easily adjusted.

  In the above, the eye width adjustment in the HMD capable of observing an image with both eyes has been described. However, the above-described configuration of the present invention can also be applied to an HMD that observes an image with one eye. That is, in an HMD that observes an image with one eye, it is possible to form an optical pupil E having a flat shape obliquely and adjust the pupil position for each observer with different eye widths by moving the image display device 1 up and down. .

  The present invention can be used for a head-mounted image display device.

(A) (b) (c) is the top view, front view, and side view which respectively show the structure of the outline of HMD which concerns on one Embodiment of this invention. It is sectional drawing which shows the schematic structure of the video display apparatus with which said HMD is provided. (A) is explanatory drawing which shows typically the optical path of the reproduction | regeneration light ray (video light ray) in an optical axis entrance plane, (b) is explanatory drawing which shows typically the shape of the optical pupil at the time of reproduction | regeneration. is there. (A) is explanatory drawing which shows typically the optical path of the exposure light beam when exposing a hologram photosensitive material, (b) is the reproduction light beam (image | video) when reproducing | regenerating using HOE produced by the said exposure. It is explanatory drawing which shows typically the optical path of a light ray. (A) is explanatory drawing which shows the diffraction peak wavelength of the light ray which injects into the center and upper and lower ends of an optical pupil, (b) is explanatory drawing which shows intensity distribution of a reproduction | regeneration light source. It is the front view before and behind rotation of one video display unit of the said video display apparatus, and typical explanatory drawing of a pupil shape. It is explanatory drawing which shows the shape of each optical pupil of the video display unit of right and left of the said video display apparatus. (A) And (b) shows the schematic structure of the nose pad drive part with which said HMD is provided, Comprising: It is sectional drawing which shows the state in which a nose pad is located below and above, respectively.

Explanation of symbols

1 video display device 1R video display unit (right eye display unit)
1L video display unit (display unit for left eye)
2 Support means 6 Nose pads (drive means)
8 Nose pad drive unit (drive means)
8a rail (nose pad drive part)
8b Knob (nose pad drive unit)
9 Drive mechanism (drive means)
15 LCD (display element)
21 Eyepiece optical system 22 Eyepiece prism (optical member)
24 Optical elements (reflection optical elements, hologram optical elements)
E Optical pupil

Claims (10)

A video display device;
Supporting means for supporting the video display device in front of the observer's eyes,
The video display device is
A display element for displaying an image;
A head-mounted display comprising a reflective optical element that reflects image light from the display element and guides it to an optical pupil,
The optical pupil has an oblique flat shape in which the major axis direction is inclined at an angle smaller than 90 degrees with respect to the eye width direction in a vertical cross section facing the face including the center of the optical pupil,
The head-mounted display, wherein the support means includes drive means for moving the video display device in a direction perpendicular to the eye width direction within the plane. When the relative angle between the major axis direction of the optical pupil and the eye width direction is θ,
0 ° <θ <45 °
The head mounted display according to claim 1, wherein:   The head mount according to claim 1, wherein the driving unit includes a nose pad that contacts an observer's nose and a nose pad driving unit that moves the nose pad up and down. display.   2. The head mounted display according to claim 1, wherein the reflection optical element is a volume phase type reflection type hologram optical element. The optical axis is an axis that optically connects the center of the display surface of the display element and the center of the optical pupil, and the optical axis that is incident on the hologram optical element from the display element side and the optical pupil side. When the surface including the optical axis to be emitted is the optical axis incident surface,
When the relative angle between the vertical plane perpendicular to the eye width direction and the optical axis entrance plane is α,
0 ° <α <90 °
The head-mounted display according to claim 4, wherein 0 ° <α <45 °
The head mounted display according to claim 5, wherein   The head-mounted display according to any one of claims 4 to 6, wherein the image light from the display element is light including at least one of a wavelength range of red, green, and blue. The image display device further includes an optical member that guides the image light from the display element by totally reflecting the light inside.
8. The head mounted display according to claim 4, wherein the hologram optical element guides the image light from the display element guided through the optical member to the optical pupil by diffracting and reflecting the image light. .   The hologram optical element has positive axially asymmetric optical power, and constitutes at least a part of an eyepiece optical system that guides image light from the display element to an optical pupil. The head mounted display in any one of 4 to 8. The video display device includes a left-eye display unit and a right-eye display unit corresponding to the left and right eyes of the observer,
Each of the display units includes the display element and the reflective optical element,
10. The head mounted display according to claim 1, wherein each of the optical pupils of both the display units has a symmetrical shape with respect to a plane perpendicular to the eye width direction.

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