JP2016170203A - Image displaying apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image displaying apparatus capable, in spite of its compactness, of see-through displaying in which an image is superposed over a bright external scene on a large screen.SOLUTION: A picture displaying apparatus EG comprises a display element DP that displays an image IM and an observation optical system LE that projects and displays the image IM to an observer eye EY in a see-through way as a virtual image so that the image IM overlaps an external scene. The observation optical system LE comprises a light emitting optical system LN that emits the light of the image IM from a side of the observer eye EY to its front and a holographic optical element HO that reflects, by the diffraction effect of light, a light ray of a specific wavelength out of light rays from the light emitting optical system LN to the observer eye EY. The holographic optical element HO so reflects the light ray as to make the reflection angle of a main light ray AX emitted from the screen center of the display element DP smaller than the positive reflection angle.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image display device. For example, a two-dimensional image of a liquid crystal display (LCD) is projected and displayed on a viewer's eye using a holographic optical element (HOE). The present invention relates to a glasses-type image display device.

  Patent Documents 1 to 3 propose spectacle-type image display devices that display an image superimposed on an outside scene (that is, an external field of view). Since these image display devices are used hands-free, it is important to display information in an optimal situation for the user. On the other hand, it is necessary to meet not only the display image but also the desire to see the outside scene well. There is. The brightness of the outside scene is particularly important, and it is not preferable that the outside scene becomes dark for image display. In addition, the viewing distance of the display image is also important. Since the user looks near or looks far away, if the display is performed at an unbalanced distance at that time, it becomes impossible to observe the outside scene and the display with good overlay. Furthermore, the width of the display screen is also important. Since it is impossible to define where the user sees, it is preferable that images can be provided as much as possible.

JP 2014-59395 A JP 2013-73070 A US 6,353,503 B1

  As described above, it is difficult to simultaneously satisfy the requirements regarding the brightness of the outside scene, the viewing distance of the display image, and the size of the display screen. For example, when a half mirror is used as described in Patent Document 1, the brightness of the outside scene becomes half or less and the outside scene becomes dark. Further, in the case of a configuration that sequentially reflects the half mirror, the object distance needs to be infinite. When the object distance is set to a short distance, the images are not overlapped by the respective half mirrors, and as a result, they appear to be blurred.

  As described in Patent Document 2, in an image display device using a half mirror (intermediate layer), the brightness of the outside scene becomes half or less and the outside scene becomes dark. Further, in the method of inserting the reflecting surface so as to be sandwiched between the spectacle lens surfaces, the thickness of the spectacle lens is increased.

  As described in Patent Document 3, if the reflecting surface is simply formed of a hologram, there is no condensing power of the hologram, so that it is necessary to collect the condensing power on a curved surface. Further, since there is no deflection effect for shifting the angle, a thickness is required to reflect the light from the side of the glasses toward the eyes. Therefore, since the angle of view is limited, image display on a large screen is impossible.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an image display device capable of see-through display in which an image is superimposed on a bright outside scene on a wide screen while being compact. is there.

In order to achieve the above object, an image display device according to a first aspect of the present invention includes a display element that displays an image and an observation that projects and displays the image as a virtual image on a viewer's eye so that the image overlaps an outside scene. An image display device having an optical system,
The observation optical system emits light of the image from the side of the observer's eye toward the front, and the observer emits light having a specific wavelength by diffracting action from the light from the projection optical system. A holographic optical element that reflects toward the eye,
The holographic optical element performs reflection by the diffractive action so that the reflection angle of the principal ray emitted from the screen center of the display element is smaller than the regular reflection angle.

  An image display device according to a second aspect of the present invention is the glasses-type image display device according to the first aspect, comprising: a temple located on the side of the observer's eye; and a transparent substrate located in front of the observer's eye. The light projecting optical system is held by the temple, and the holographic optical element is held by the transparent substrate.

An image display device according to a third aspect of the invention is characterized in that, in the first or second aspect of the invention, the following conditional expression (1) is satisfied.
| Θ ′ | /θ≦0.2 (1)
However,
θ: incident angle,
θ ′: reflection angle,
The direction from the surface normal to the specular reflection side is positive, and the direction from the surface normal to the incident side is negative.

  The image display device of a fourth invention is characterized in that, in any one of the first to third inventions, a virtual image formed by the observation optical system is located at a finite distance with respect to an observer's eye. .

  The image display device of a fifth invention is characterized in that, in the fourth invention, the distance from the observer's eye to the virtual image formed by the observation optical system is 30 cm or more and 5 m or less.

  The image display device of a sixth invention is characterized in that, in any one of the first to fifth inventions, the holographic optical element has a condensing power by a diffraction action.

  According to a seventh aspect of the present invention, there is provided the image display device according to the sixth aspect, wherein the holographic optical element has a condensing power by concave reflection.

  An image display apparatus according to an eighth invention is characterized in that, in any one of the first to seventh inventions, an intermediate image is formed between the light projecting optical system and the holographic optical element.

  An image display device according to a ninth aspect of the invention is characterized in that, in any one of the first to eighth aspects of the invention, the image display device has a function of performing focusing by adjusting an interval from the display element to the light projecting optical system. And

  According to a tenth aspect of the present invention, in any one of the first to ninth aspects, the light projecting optical system is a non-axisymmetric optical system.

  In an image display device according to an eleventh aspect of the invention, in any one of the first to tenth aspects of the invention, the light projecting optical system generates chromatic aberration in a direction that cancels chromatic aberration generated in the holographic optical element. Features.

  According to the present invention, it is possible to realize an image display device capable of see-through display that is compact and has an image superimposed on a wide screen on a bright outside scene.

1 is a schematic cross-sectional view schematically showing a first embodiment of an eyeglass-type image display device. The optical block diagram of 1st Embodiment (Example 1) of a spectacles type image display apparatus. The optical block diagram of 2nd Embodiment (Example 2) of a glasses-type image display apparatus.

  Hereinafter, an image display device and the like according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is mutually attached | subjected to the part which is the same in each embodiment etc., and the corresponding part, and duplication description is abbreviate | omitted suitably.

  FIG. 1 shows a schematic cross-sectional structure of the image display device EG of the first embodiment as viewed from above. The image display device EG includes a display element DP (for example, LCD) for displaying the image IM, a light source LS (for example, LED (light emitting diode)) for illuminating the display element DP, and the image IM so as to overlap the outside scene. And an observation optical system LE that projects and displays the image IM as a virtual image on the observer eye EY in a see-through manner. The observation optical system LE diffracts light of a specific wavelength among the light projection optical system LN that emits the light of the image IM from the side of the observer eye EY toward the front, and the light from the light projection optical system LN. And a volume phase holographic optical element HO that reflects toward the observer eye EY. 1 is a diagram of a transmissive liquid crystal element, DP may be a reflective liquid crystal element, a digital micromirror device (DMD), or an organic EL display. Further, an illumination optical system constituted by a lens or a mirror may be disposed between the light sources LS and DP.

  Furthermore, since the image display device EG has a glasses-like form, temples 2a and 2b positioned on the side of the observer eye EY, transparent substrates 1a and 1b positioned in front of the observer eye EY, A bridge 3 that connects the transparent substrates 1a and 1b, the light projecting optical system LN is held by the temple 2a, and the holographic optical element HO is held by the substrate surface 1s of the transparent substrate 1a. The light source LS, the display element DP, and the light projecting optical system LN are housed in the housing 4, and the housing 4 is held by the temple 2a.

  The observer can hold the image display device EG in front of the eyes with the temples 2a and 2b in the same manner as normal glasses. The display element DP displays an image by modulating the illumination light from the light source LS. The image light emitted from the display element DP is projected forward by the light projecting optical system LN, then diffracted and reflected by the holographic optical element HO, and enters the pupil EP. Since the holographic optical element HO has a positive power (power: an amount defined by the reciprocal of the focal length), the image light is observed as a virtual image by being incident on the pupil EP of the observer eye EY. . In addition, external light (that is, light from an external scene) passes through the holographic optical element HO, and the display image is projected and displayed as a virtual image on the observer's eye EY as a virtual image so as to overlap the external visual field. Therefore, the observer can see the outside scene through the transparent substrates 1a and 1b while observing the image of the display element DP covered by the housing 4 as a virtual image.

  Speaking from the relationship between the holographic optical element HO as a combiner and image light, for example, a BGR-integrated LED with center wavelengths of 470 nm, 530 nm, and 640 nm is used as the light source LS, and the wavelength 470 nm ± 10 nm as the holographic optical element HO, It is preferable to use a light beam produced so as to diffract image light having a wavelength of 530 nm ± 10 nm and a wavelength of 640 nm ± 10 nm. Since the holographic optical element HO diffracts only light having a specific incident angle and specific wavelength, it hardly affects external light. Therefore, since external light passes through the transparent substrate 1a and the holographic optical element HO, the normal external environment can be seen.

  Although it is very difficult to construct an image display device in a small and limited structure called glasses, it is essential to achieve a reduction in size and thickness in a spectacle-type image display device worn on the head. In particular, if there is a heavy lens part (front side), the wearability is not good. Therefore, it is preferable that the display element and the light projecting optical system used for image projection are positioned as far back as possible. Therefore, in the image display device EG, the display element DP, the light projecting optical system LN, and the like are arranged on the temple 2a so that the center of gravity of the image display device EG is located on the rear side.

  And in order to improve mounting | wearability and implement | achieve size reduction and thickness reduction, the holographic optical element HO which utilized the diffraction effect effectively is used as a reflective optical element arrange | positioned in the front side. That is, in the image display device EG, the holographic optical element HO is diffracted so that the reflection angle of the principal ray (corresponding to the optical axis AX) emitted from the center of the display element DP is smaller than the regular reflection angle. It is characterized by performing reflection by action.

  In a spectacle-type image display device, when the lens portion is provided with a reflecting structure, if the projection optical system LN is on the side of the observer's eye EY, as shown in FIG. On the other hand, since the lens portion is inclined, the lens portion becomes thick, and it is difficult to increase the angle of view if the thickness is to be suppressed. Therefore, in the image display device EG, the reflection angle is largely shifted using the diffraction action of the holographic optical element HO. By shifting the reflection angle, it is possible to bend (that is, deflect) the optical path toward the pupil EP while being thin. In addition to the deflection effect of shifting the reflection angle, the holographic optical element HO has a feature suitable as a combiner that has high light transmittance, and its effective luminous transmittance is 80% or more.

  Therefore, it is possible to realize an image display device EG capable of see-through display that is compact and has an image superimposed on a wide screen on a bright outside scene. In addition, if the above characteristic holographic optical element HO is used, in an image display device such as an HMD (head mounted display) or HUD (headup display) other than the glasses type in which the light projecting optical system LN is held by the temple 2a. It is possible to obtain the above effect.

Regarding the deflected reflection by the diffractive action at the holographic optical element HO, it is desirable to satisfy the following conditional expression (1). More preferably, the upper limit is preferably 0.1. Thinning can be realized by reducing θ ′.
| Θ ′ | /θ≦0.2 (1)
However,
θ: incident angle,
θ ′: reflection angle,
The direction from the surface normal to the specular reflection side is positive, and the direction from the surface normal to the incident side is negative.

  If the conditional expression (1) is satisfied, the surface of the holographic optical element faces the pupil plane, so that it is possible to effectively reduce the thickness. Further, the incident angle θ when the holographic optical element surface faces the pupil surface is preferably 20 to 70 °. When the incident angle θ is set to 20 ° or more, the arrangement of the light projecting optical system LN and the like with respect to the temple 2a becomes easy. When the incident angle θ is set to 70 ° or less, it becomes easy to correct chromatic aberration caused by diffraction and non-axisymmetric aberration. More preferably, the upper limit is 45 degrees. A high-resolution display element can be used.

  The virtual image formed by the observation optical system LE is preferably located at a finite distance with respect to the observer eye EY, and the distance from the observer eye EY to the virtual image formed by the observation optical system LE is 30 cm or more and 5 m or less. It is further desirable. When the virtual image position of the display image is set to a finite distance, for example, the diopter during walking can be easily switched. Therefore, it is effective in improving the see-through overlap between the display image IM and the outside scene.

  It is preferable that the holographic optical element HO has a condensing power due to diffraction action, and it is further preferable that the holographic optical element HO has a condensing power due to concave reflection. In the image display device EG, the substrate surface 1s of the transparent substrate 1a is a concave curved surface, and the holographic optical element HO is disposed on the substrate surface 1s. In other words, the deflection reflection at the holographic optical element HO is performed only by the diffraction action, but the condensing reflection at the holographic optical element HO is performed by the diffraction power and the curved surface power.

  If condensing reflection is performed only on the concave surface, when a small display panel is used as the display element DP, the curvature of the concave surface becomes large, and there is a possibility that a bad effect such as distortion of the transmitted image may occur. Therefore, it is preferable to use a curved surface having a curvature similar to that of a spectacle lens in order to achieve a wide angle of view. Further, when the substrate surface 1s is configured as a flat surface, the condensing reflection at the holographic optical element HO is performed only by the diffraction power. That is, the condensing power is all borne by the holographic optical element HO. If condensing reflection is performed with only the diffraction power, it becomes difficult to correct chromatic aberration generated in the holographic optical element. In the image display device EG, it is possible to effectively reduce the chromatic aberration by placing a part of the condensing power of the holographic optical element HO on the curved surface. In the image display device EG, the holographic optical element HO is held on the substrate surface 1s of the transparent substrate 1a. However, the holographic optical element HO may be disposed in the transparent substrate 1a. Further, the holographic optical element HO may be disposed on the outer surface of the transparent substrate.

  In the image display device EG, a bright image display is possible by using the projection optical system LN in the observation optical system LE. In addition, the image plane can be arranged at a position where aberration can be corrected together with the holographic optical element HO, and a large angle of view can be realized by using a small display element DP. That is, it is desirable to form an intermediate image between the light projecting optical system LN and the holographic optical element HO. If the focal length of the holographic optical element HO is shortened in order to increase the angle of view, the display element DP needs to be arranged in the vicinity of the eyes. However, if an intermediate image is formed, the display element DP is in the vicinity of the observer eye EY. The angle of view can be increased without disposing the display element DP.

  The image display device EG preferably has a function of performing focusing by adjusting the distance from the display element DP to the light projecting optical system LN. When the distance from the display element DP to the light projecting optical system LN is adjusted by moving the whole or part of the light projecting optical system LN or the display element DP, the virtual image position of the display image IM with respect to the observer eye EY It is possible to adjust the focus, that is, diopter adjustment.

  Here, the specific optical configuration of the image display device EG will be described in more detail. 2 and 3 are optical configuration diagrams respectively corresponding to the observation optical systems LE constituting the first and second embodiments, and their optical arrangements, optical paths, and the like are shown by optical cross sections. These observation optical systems LE are composed of a light projecting optical system LN including a first lens L1, a second lens L2, and a third lens L3, and a holographic optical element HO in this order from the image IM side.

  In the first embodiment (FIG. 2), the light projecting optical system LN is an axially symmetric optical system, whereas in the second embodiment (FIG. 3), the light projecting optical system LN is non-axisymmetric optical. It is a system. In the first embodiment, the deflection reflection at the holographic optical element HO is performed only by the diffraction action, and the condensing reflection at the holographic optical element HO is performed by a combination of the diffraction power and the curved surface power. In the second embodiment, the deflection reflection at the holographic optical element HO is performed only by the diffraction action, and the condensing reflection at the holographic optical element HO is performed only by the diffraction power.

  In the case of the first embodiment (FIG. 2), the converging reflection at the holographic optical element HO is performed by the diffraction power and the curved surface power, so that the occurrence of chromatic aberration at the holographic optical element HO can be reduced. Is possible. In the case of the second embodiment (FIG. 3), since the condensing reflection at the holographic optical element HO is performed only by the diffraction power, the light projecting optical system LN cancels the chromatic aberration generated at the holographic optical element HO. It is configured to generate directional chromatic aberration. That is, the asymmetric chromatic aberration caused by the obliquely asymmetrical deflection reflection at the holographic optical element HO is caused by the free-form prism effect provided on the first and third lenses L1 and L3 of the light projecting optical system LN. It is possible to effectively correct by generating the lateral shift.

  Hereinafter, the configuration and the like of the image display apparatus embodying the present invention will be described more specifically with reference to the construction data of the examples. Examples 1 and 2 listed here are numerical examples respectively corresponding to the first and second embodiments described above, and the schematic sectional view (FIG. 1) showing the first embodiment corresponds to the corresponding implementation. The optical arrangement, optical path, etc. of Example 1 are shown, and the optical configuration diagrams (FIGS. 2 and 3) representing the first and second embodiments show the optical arrangement, optical path, etc. of the corresponding Examples 1 and 2. Each is shown.

  As construction data of each example, surface data 1, surface data 2, and various data are shown, and for example 2, free-form surface data is further shown. In the surface data 1 and 2, i (i = 1, 2, 3,...) Is a surface number. The position of the virtual image VP formed by the observation optical system LE is the first surface, the position of the pupil EP is the second surface, and the attachment surface of the holographic optical element HO is the third surface. Furthermore, the exit surface and the entrance surface of the third lens L3 are the fourth surface and the fifth surface, the exit surface and the entrance surface of the second lens L2 are the sixth surface and the seventh surface, and the exit surface of the first lens L1 and The incident surfaces are the eighth surface and the ninth surface. The tenth surface as the final surface is a display surface of the display element DP that displays the image IM. In the surface data 1, in order from the left column, the surface number i, the radius of curvature r (mm), the axial top surface distance d (mm), the refractive index nd for the d-line (wavelength 587.56 nm), and the Abbe number vd for the d-line. In the plane data 2, the arrangement data of the i-th plane is shown.

  The arrangement of the i-th surface is specified by each surface data of the surface vertex coordinates (x, y, z) and the rotation angle α in the surface data 2. The surface vertex coordinates of the i-th surface are the local orthogonal coordinate system (X, y, z) in the global orthogonal coordinate system (x, y, z) with the surface vertex as the origin of the local orthogonal coordinate system (X, Y, Z). Y, Z) is represented by the coordinates (x, y, z) of the origin (unit: mm), and the inclination of the i-th surface is represented by the rotation angle α around the X axis centering on the surface vertex. (Unit: °; counterclockwise with respect to the positive direction of the X axis is the positive direction of the rotation angle of the X rotation). However, the coordinate systems are all defined by the right-handed system, and the global orthogonal coordinate system (x, y, z) is an absolute coordinate system that matches the local orthogonal coordinate system (X, Y, Z) of the pupil EP. ing. Accordingly, the X direction and the Y direction are coordinate axis directions in an orthogonal coordinate system (X, Y, Z) in which the surface vertex of the i-th surface is the origin and the normal line at the surface vertex is the Z axis, and the x direction Is a direction perpendicular to the paper surface (up and down direction of the angle of view), and y direction is a vertical direction of the paper surface (left and right direction of the field angle).

Regarding the free-form surface data of the second embodiment, the i-th surface composed of a free-form surface (XY polynomial surface) is expressed by the following equation (FS) using a local orthogonal coordinate system (X, Y, Z) with the surface vertex as the origin. ). Free surface coefficients and the like are shown as free surface data. However, A (j, k) is expressed by X ^j · Y ^k . Note that the coefficient of the term not described is 0, and E−n = × 10 ⁻ⁿ for all data.
Z = (C0 · h ² ) / [1 + √ {1- (1 + K) · C0 ² · h ² }] + ΣΣ {A (j, k) · X ^j · Y ^k } (FS)

However, in the formula (FS),
Z: Displacement amount in the Z-axis direction at the position of height h (based on the surface vertex),
h: height in the direction perpendicular to the Z axis (h ² = X ² + Y ² ),
C0: curvature at the surface vertex (= 1 / r),
K: Conic constant,
A (j, k): j-th order of X, k-th order polynomial free-form surface coefficient of Y,
It is.

  As various data, diameter (mm) of pupil EP, angle of view (°) and screen size (mm) in Y direction (screen long side direction) and X direction (screen short side direction), deflection by holographic optical element HO The type of reflection / condensation / reflection, the incident angle of the screen center principal ray with respect to the holographic optical element HO (the principal ray emitted from the screen center of the display element DP, which corresponds to the optical axis AX in Examples 1 and 2). θ and reflection angle θ ′, the corresponding value of conditional expression (1), the thickness (μm) of holographic optical element HO, and exposure conditions are shown.

Example 1
Surface data 1
ir (mm) d (mm) nd vd
1 (VP) ∞ -1000.0
2 (EP) ∞ 25.0
3 (HO) -50.0000
4 (L3) -6.6604 3.0 1.5168 64.1
5 (L3) 283.3587 1.0
6 (L2) -3.3784 2.0 1.5168 64.1
7 (L2) -5.1918 2.0
8 (L1) 2.8963 2.0 1.5168 64.1
9 (L1) 1.9408 5.0
10 (IM) ∞

Surface data 2
ixyz α
1 (VP) 0 0.0000 -1000.0000 0.0000
2 (EP) 0 0.0000 0.0000 0.0000
3 (HO) 0 0.0000 25.0000 0.0000
4 (L3) 0 11.9034 0.3647 -25.7891
5 (L3) 0 13.2086 -2.3365 -25.7891
6 (L2) 0 13.6436 -3.2369 -25.7891
7 (L2) 0 14.5138 -5.0377 -25.7891
8 (L1) 0 15.3839 -6.8385 -25.7891
9 (L1) 0 16.2540 -8.6393 -25.7891
10 (IM) 0 18.4293 -13.1413 -25.7891

Various data pupil diameter: 3mm
Angle of view: Left and right direction (Y direction) ± 10 degrees, up and down direction (X direction) ± 6 degrees
Horizontal (Y direction) 3.44 mm x Vertical (X direction) 2.30 mm
Deflection and reflection at the HOE: diffraction effect only Condensation and reflection at the HOE: diffraction power + curved surface power HOE incident angle θ and reflection angle θ ′ with respect to the HOE
Incident angle θ: 25.7 degrees Reflection angle θ ′: 0 degrees Conditional expression (1): | θ ′ | / θ = 0
HOE thickness: 20μm
HOE exposure conditions Wavelength: R647nm, G532nm, B477nm
Parallel light Exposure from the right side in Fig. 2 (exposure from + Z direction to -Z direction)
Divergent light Exposure from the left side of Fig. 2 (exposure from -Z direction to + Z direction)
Divergence point of diverging light (surface vertex reference): (Y, Z) = (30 mm, −70 mm)
Blue: Argon ion laser (476.5 nm)
Green: Solid laser (532nm)
Red: Krypton ion laser (647.1 nm)

Example 2
Surface data 1
ir (mm) d (mm) nd vd
1 (VP) ∞ -1000.0
2 (EP) ∞ 25.0
3 (HO) ∞
4 (L3) -5.6885 3.0 1.5168 64.1
5 (L3) 11.8183 1.0
6 (L2) -33.4235 2.0 1.5168 64.1
7 (L2) 170.0732 2.0
8 (L1) 13.9679 2.0 1.5168 64.1
9 (L1) 10.6651 5.0
10 (IM) ∞

Surface data 2
ixyz α
1 (VP) 0 0.0000 -1000.0000 0.0000
2 (EP) 0 0.0000 0.0000 0.0000
3 (HO) 0 0.0000 25.0000 0.0000
4 (L3) 0 10.3786 1.8802 -17.3307
5 (L3) 0 11.2723 -0.9836 -17.3307
6 (L2) 0 11.5702 -1.9382 -17.3307
7 (L2) 0 12.1659 -3.8474 -17.3307
8 (L1) 0 12.7617 -5.7566 -17.3307
9 (L1) 0 13.3575 -7.6658 -17.3307
10 (IM) 0 14.8469 -12.4388 -27.7806

Fifth surface free-form surface data (XY polynomial)
K: -5.2207E + 00
Y: 6.7018E-01
X2: -7.9349E-02
Y2: -7.3470E-02
X2Y: -2.0431E-03
Y3: -1.2904E-03
X4: 9.5386E-05
X2Y2: -2.4057E-03
Y4: 4.7992E-04
X4Y: -5.2011E-04
X2Y3: 6.6944E-04
Y5: -1.1993E-04
X6: 3.5940E-07
X4Y2: 1.2389E-04
X2Y4: -3.3248E-05
Y6: 1.3616E-05

10th surface free-form data (XY polynomial)
K: -5.2111E-01
Y: -1.3557E + 00
X2: -1.7007E-02
Y2: 1.7092E-01
X2Y: 8.5501E-02
Y3: 1.9184E-02
X4: 4.6841E-03
X2Y2: -6.4199E-02
Y4: -2.0803E-02
X4Y: 5.7564E-05
X2Y3: 1.2288E-02
Y5: 4.1813E-03
X6: 4.7389E-04
X4Y2: 8.8947E-04
X2Y4: -4.0715E-04
Y6: -1.7996E-04

Various data pupil diameter: 3mm
Angle of view: Left and right direction (Y direction) ± 10 degrees, up and down direction (X direction) ± 6 degrees
Horizontal (Y direction) 4.08 mm x Vertical (X direction) 2.96 mm
Deflection and reflection at the HOE: Only diffraction action Condensation and reflection at the HOE: Only diffraction power The incident angle θ and the reflection angle θ '
Incident angle θ: 28.6 degrees Reflection angle θ ′: 0 degrees Conditional expression (1): | θ ′ | / θ = 0
HOE thickness: 30 μm
HOE exposure conditions Wavelength: R647nm, G532nm, B477nm
Parallel light Exposure from the right side in Fig. 3 (exposure from + Z direction to -Z direction)
Divergent light Exposure from the left side of Fig. 3 (exposure from -Z direction to + Z direction)
Divergence point of divergent light (surface vertex reference): (Y, Z) = (7.55 mm, −15.7 mm)
Blue: Argon ion laser (476.5 nm)
Green: Solid laser (532nm)
Red: Krypton ion laser (647.1 nm)

EG Image display device LE Observation optical system LN Projection optical system HO Holographic optical element DP Display element LS Light source IM Image AX Optical axis (principal ray emitted from the center of the screen)
1a, 1b Transparent substrate 1s Substrate surface 2a, 2b Temple 3 Bridge 4 Housing EP Pupil EY Observer eye

Claims (11)

An image display device comprising: a display element that displays an image; and an observation optical system that projects and displays the image as a virtual image on a viewer's eye so that the image overlaps an outside scene,
The observation optical system emits light of the image from the side of the observer's eye toward the front, and the observer emits light having a specific wavelength by diffracting action from the light from the projection optical system. A holographic optical element that reflects toward the eye,
The image display apparatus, wherein the holographic optical element performs reflection by the diffraction action so that a reflection angle of a principal ray emitted from a screen center of the display element is smaller than a regular reflection angle.   An eyeglass-type image display device comprising a temple located on the side of the observer's eye and a transparent substrate located in front of the observer's eye, wherein the light projecting optical system is held by the temple 2. The image display device according to claim 1, wherein the holographic optical element is held on the transparent substrate. The image display device according to claim 1, wherein the following conditional expression (1) is satisfied:
| Θ ′ | /θ≦0.2 (1)
However,
θ: incident angle,
θ ′: reflection angle,
The direction from the surface normal to the specular reflection side is positive, and the direction from the surface normal to the incident side is negative.   The image display apparatus according to claim 1, wherein a virtual image formed by the observation optical system is located at a finite distance with respect to an observer's eye.   The image display apparatus according to claim 4, wherein a distance from an observer's eye to a virtual image formed by the observation optical system is 30 cm or more and 5 m or less.   The image display apparatus according to claim 1, wherein the holographic optical element has a condensing power by a diffraction action.   The image display device according to claim 6, wherein the holographic optical element has a condensing power by concave reflection.   The image display device according to claim 1, wherein an intermediate image is formed between the light projecting optical system and the holographic optical element.   The image display device according to claim 1, wherein the image display device has a function of performing focusing by adjusting an interval from the display element to the light projecting optical system.   The image display apparatus according to claim 1, wherein the projection optical system is a non-axisymmetric optical system.   The image display apparatus according to claim 1, wherein the projection optical system generates chromatic aberration in a direction that cancels chromatic aberration generated in the holographic optical element.

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