JP2002090692A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device which is small-sized, has high performance, and is equipped with an ocular optical system capable of securing long actuation distance. SOLUTION: The ocular optical system 3 is provided with a 1st optical element 10, which has at least one reflecting surface and deflect the optical path sideward about the view axis 2 of an observer, a 2nd optical element 20 which has at least one reflecting surface and deflects the optical path deflected sideward by the 1st optical element away from the observer, and a 3rd optical element 30 which has at least one reflecting surface and deflects the optical path deflected by the 2nd optical element, almost in direction substantially opposite to the direction of the deflection by the 1st optical element in reverse tracking order; and the 2nd and 3rd optical elements constitute a relay optical system for an image displayed by an image display element 5, and the 1st and 3rd optical elements have positive power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device and, more particularly, to a method for displaying a bright image on a display device of a type that displays an image by reflected light, such as a reflection type liquid crystal display device, with a small size and a wide angle of view. The present invention relates to an image display device such as a head-mounted display that is devised so that observation can be performed through an eyepiece optical system that is suppressed as much as possible.

[0002]

2. Description of the Related Art In recent years, with the development of head-up displays and glasses-type displays, the development of compact eyepiece optical systems has been advanced.
An eyepiece optical system using a thin and compact eccentric prism described in Japanese Patent Application Laid-Open No. 50256/1996 and Japanese Patent Application Laid-Open No. 8-234137 has been proposed. These are compact eyepiece optical systems in which the reflecting surface has power and the optical path is folded, and the rotationally asymmetrical decentering aberration caused by the decentering reflecting surface having power is reduced by the anamorphic reflecting surface and one symmetrical one. The correction is performed using a rotationally asymmetric reflecting surface having a surface.

[0003] Further, regarding a liquid crystal display element for displaying an observation image, in order to form a brighter and easier-to-observe image,
A reflection type liquid crystal display element has been developed, and Japanese Unexamined Patent Application Publication No. 10-268306 discloses a type including the illumination mode.

An eyepiece optical system using two decentered prisms has also been proposed in Japanese Patent Laid-Open No. 2000-199853.

[0005]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open
In the image display device of 000-199853, since the two eccentric prisms extend in the direction perpendicular to the visual axis and are long, it is hard to say that the eyepiece optical system is downsized. In addition, since the distance (working distance: WD) between the image display element and the eccentric prism immediately before the image display element is short, when a reflective liquid crystal display element is used as the image display element, a light splitting element for introducing illumination light is arranged. Is difficult to do.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems of the prior art, and has as its object to provide an image having an eyepiece optical system which is compact, has a wide angle of view, has a high performance, and can secure a long working distance. It is to provide a display device.

[0007]

According to the present invention, there is provided an image display apparatus, comprising: an image display element; an image displayed on the image display element; An image display apparatus including an eyepiece optical system having a positive power as a whole, wherein the eyepiece optical system has at least one reflecting surface in the order of backward ray tracing from the exit pupil to the image display element. A first optical element that bends the optical path laterally with respect to the visual axis of the observer, and at least one reflecting surface, wherein the optical path bent laterally by the first optical element is bent in a direction away from the observer A second optical element, and at least one reflecting surface, wherein the optical path bent by the second optical element in a direction away from the observer is bent in a direction substantially opposite to the direction bent by the first optical element. ; And a third optical element, the second
The optical element and the third optical element constitute a relay optical system for an image displayed on the image display element, and at least the first optical element and the third optical element have positive power. Is what you do.

[0008] Hereinafter, the reason and operation of the above configuration in the present invention will be described.

First, an optical axis is defined. An axial principal ray passing through the center of the exit pupil and passing through the center of the image display element is defined as an optical axis.

FIG. 7 is a cross-sectional view including an optical axis of a first embodiment described later. The configuration of the optical system is considered starting from the observer's eyeball (exit pupil 1). A direction from the exit pupil 1 toward the eyepiece optical system 3 is defined as a direction A. On-axis chief ray 2 incident on eyepiece optical system 3
After the reflection and refraction at the first optical element 10, the light travels in a direction B that is substantially perpendicular to the direction A. Thereafter, the light is reflected and refracted by the second optical element 20 again, and travels in the direction A ′ substantially parallel to the direction A. Further, the light reaches the display surface 5 of the image display element in the direction C opposite to the direction B due to reflection and refraction at the second optical element 30. in this way,
By folding the axial principal ray 2 by using the reflection and refraction at the three optical elements 10, 20, 30 in the eyepiece optical system 3, the eyepiece optical system 3 can be made compact.

Here, in order to define each direction more strictly, the following is considered. The starting point and the ending point in each direction are the intersections of the axial principal ray 2 and the reflecting surface (however, the starting point in the A direction is the center of the exit pupil 1 and the ending point in the C direction is the display surface 5 of the image display element). It is the center.) Each direction is assumed to end when the axial principal ray 2 reaches the next reflection surface. A straight line connecting the starting point and the ending point in each direction is defined as a straight line defining the direction. In general, this direction does not coincide with the axial chief ray 2 (because there is a refractive surface in between). In an optical system having more than three reflecting surfaces, there is a direction of the axial chief ray 2 which does not belong to any of the directions defined above.

A more detailed description will be given based on Embodiment 1 in FIG. In this embodiment, the center of the exit pupil 1 is defined as P, and the intersection between the axial principal ray 2 and each surface is marked. The first refracting surface is point A, the next reflecting surface is point B, and the point that hits the first refracting surface again is point A '. At point A ', the light beam is totally reflected.
The prism of the first optical element 10 is emitted from the next refracting surface. Next, the point entering the prism of the second optical element 20 again is point D, the next total reflection surface is point E, the exit point of this second prism is point F, and the next prism is incident on the third optical element 30. The point is point G, the next reflecting surface is point H, the point reflecting one more time is point I, and the point emitting this prism is J.
Point. Next, the point incident on the illumination prism 4 is point K,
Let the emission point of the illumination prism 4 be point L and the center point of the image display surface 5 be point M.

Here, each direction is defined by a point P and a point B.
The straight line connecting the points is in the direction A, and the direction connecting the points A 'and E is B.
The direction connecting the points E and H is the direction A ', and the direction connecting the points I and M is the direction C.

In each of the following embodiments, the second optical element 2
The intermediate image forming position of the display surface 5 of the image display element by the 0 and the third optical element 30 is near the point D of the second optical element 20.

Here, the limitation on the folding direction of the folded optical system will be considered. It is desirable that the B direction and the C direction are substantially anti-parallel. Assuming that the angle formed between the B direction and the C direction is θ, θ is within 180 °. However, a straight line that defines the B direction and a straight line that defines the C direction are considered, and an intersection point Q between them is set. When the point Q is on the opposite side of the straight line defining the direction A ′ to the straight line defining the direction A (spread downward in FIG. 7), it is assumed to be smaller than 180 °, and on the same side as the straight line defining the direction A. It is assumed that the case where there is (spread upward in FIG. 7) is larger than 180 °.

In the structure of the present invention, it is desirable that the following condition is satisfied: 100 ° <θ <200 ° (1) When the upper limit of 200 ° to condition (1) is exceeded, the distance between the center of the image display element and the first optical element 10 becomes too short, causing interference between the image display element and the first optical element 10 to cause an image display device. Is difficult to configure. If the lower limit of 100 ° is exceeded, there will be too much space between the image display element and the first optical element 10 in the future, resulting in an increase in the size of the image display device.

More preferably, it is preferable to satisfy 120 ° <θ <180 ° (1-1).

More preferably, it is more preferable to satisfy the following condition: 150 ° <θ <170 ° (1-2).

In the embodiments described below, It is.

Incidentally, it is desirable that at least one reflecting surface of the first optical element is formed in a rotationally asymmetric curved surface shape giving a positive power. By causing the reflection surface to carry the positive power of the first optical element, the occurrence of chromatic aberration can be reduced. However, if the reflecting surface is formed as a concave inclined surface, asymmetric aberration occurs. To correct this, it is desirable to form the reflecting surface into a rotationally asymmetric curved surface. In general, the rotationally asymmetric surface is symmetric with respect to a plane including the normal line at the point of incidence of the axial chief ray and the axial chief ray. Considering its manufacturability, a rotationally asymmetric surface having two symmetric surfaces may be used as the reflection surface.

Here, the rotationally asymmetric surface used in the present invention is preferably a plane-symmetric free-form surface having only one or two symmetry surfaces. Here, the free-form surface used in the present invention is defined by the following equation (a). Note that the Z axis of the definition formula is the axis of the free-form surface.

[0022] Here, the first term of the equation (a) is a spherical term, and the second term is a free-form surface term.

In the spherical term, c: curvature of the vertex k: conic constant (conical constant) r = √ (X ² + Y ² ).

The free-form surface term is Here, C _j (j is an integer of 2 or more) is a coefficient.

The free-form surface generally includes an XZ plane,
Although neither YZ plane has a plane of symmetry, in the present invention, X
By setting all the odd-order terms of 0 to 0, the YZ plane and the flat
The free-form surface has only one line of symmetry plane. example
For example, in the above definition formula (a), C_Two, C_Five, C₇,
C₉, C₁₂, C₁₄, C₁₆, C₁₈, C₂₀, C_{twenty three}, C_{twenty five}, C
₂₇, C₂₉, C₃₁, C₃₃, C₃₅Set the coefficient of each term of ... to 0
It is possible by doing.

By setting all the odd-order terms of Y to 0, a free-form surface having only one symmetry plane parallel to the XZ plane is obtained. For example, in the above definition formula, C ₃ ,
_{C 5, C 8, C 10} , C 12, C 14, C 17, C 19, C 21, C
₂₃ , C ₂₅ , C ₂₇ , C ₃₀ , C ₃₂ , C ₃₄ , C ₃₆ ...

Further, one of the directions of the above-mentioned symmetry plane is defined as a symmetry plane, and the eccentricity in the corresponding direction, for example, the eccentric direction of the optical system with respect to the symmetry plane parallel to the YZ plane is in the Y-axis direction. By making the eccentric direction of the optical system the X-axis direction with respect to the symmetric plane parallel to the XZ plane, it is possible to effectively correct rotationally asymmetric aberrations caused by the eccentricity while improving the productivity. Becomes possible.

Also, the above-mentioned definition formula (a) is shown as one example as described above, and the present invention uses a rotationally asymmetric surface having only one or two symmetry surfaces to achieve eccentricity. The feature is that the generated rotationally asymmetric aberration is corrected, and at the same time, the manufacturability is improved, and it goes without saying that the same effect can be obtained for any other defined expressions.

For the same reason, it is preferable that at least one reflecting surface of the third optical element is formed to have a rotationally asymmetric curved surface giving a positive power.

Furthermore, in order to be able to satisfactorily correct decentering aberration, it is desirable that at least one refracting surface of the first optical element is formed in a rotationally asymmetric curved surface shape having power.

It is preferable that at least one refracting surface of the third optical element is formed in a rotationally asymmetric curved surface shape having power.

Furthermore, it is desirable that at least one refracting surface of the second optical element is formed in a rotationally asymmetric curved surface shape having power.

Here, the magnification of the relay optical system including the second optical element and the third optical element will be examined. When the magnification of the relay optical system increases, the working distance of the relay optical system on the image display element side relatively decreases, and when trying to secure the working distance, the entire relay optical system increases. The eyepiece optical system of the present invention forms an intermediate image once by a relay optical system, and further enlarges and observes the intermediate image with a first optical element of an observation optical system. However, the magnification in the relay optical system is small. Then, it is necessary to increase the magnification in the observation optical system, and the resolution required for the observation optical system is increased, so that it is difficult to configure the first optical element of the observation optical system. Therefore, it is desirable that the magnification of the relay optical system be around 1: 1. Therefore, when the magnification of the relay optical system is M, 0.5 <M <2.0 (2) More preferably, 0.8 <M <1.4 (2-1) Preferably, it is satisfied.

It is more preferable that the following condition is satisfied: 0.9 <M <1.2 (2-2).

In the examples described below, It is.

The distance (working distance) between the refracting surface of the third optical element closest to the image display element and the image display surface of the image display element is WD, and the diagonal length of the image display surface of the image display element is WD. Where D is 0.8, it is preferable that 0.8 <WD / D <1.5 (3) be satisfied.

If the lower limit of this conditional expression is smaller than 0.8,
There is not enough space for disposing a light splitting element for introducing illumination light on the image display surface. If the upper limit of 1.5 is exceeded, the optical system of the image display device cannot be made compact.

It is more preferable that the following condition is satisfied: 0.9 <WD / D <1.3 (3-1)

More preferably, it is more preferable to satisfy the following condition: 1.0 <WD / D <1.15 (3-2)

In the examples described below, It is.

In the present invention, one or more of the first optical element, the second optical element, and the third optical element are made of a medium whose refractive index (n) is larger than 1 (n> 1). Composed of the formed prism members,
An incident surface on which the light beam emitted from the optical element, the third optical element, and the image display device enters the prism, at least one reflecting surface for reflecting the light beam in the prism, and an emission surface for emitting the light beam out of the prism It is desirable to have a surface.

In particular, the prism member of the first optical element has an incident surface on which the light beam emitted from the second optical element enters the prism, a reflecting surface for reflecting the light beam reflected on the exit surface within the prism, It can be configured as an eccentric prism composed of an exit surface that reflects the light beam incident on the prism from the incident surface and emits the light beam reflected on the reflection surface to the outside of the prism.

The prism member of the third optical element has an incident surface on which the light beam emitted from the image display device enters the prism, and a first reflecting surface for reflecting the light beam incident on the prism from the incident surface. And a second reflecting surface that reflects the light beam reflected by the first reflecting surface; and an emission surface that emits the light beam reflected by the second reflecting surface out of the prism. It can be constituted as an eccentric prism in which the principal ray and the axial principal ray reflected from the second reflecting surface intersect in the prism member.

The prism member of the second optical element has an incident surface on which the light beam emitted from the third optical element enters the prism, and a reflecting surface for reflecting the light beam incident on the prism from the incident surface. And an exit surface for emitting the light beam reflected by the reflection surface to the outside of the prism.

Further, the second optical element and the third optical element are constituted by an integral prism member, so that the exit surface of the third optical element and the incident surface of the second optical element can be omitted.

Further, the first optical element and the second optical element are constituted by an integral prism member, so that the exit surface of the second optical element and the incident surface of the first optical element can be omitted.

Further, the first optical element, the second optical element, and the third optical element are constituted by an integral prism member, and the exit surface of the third optical element and the entrance surface of the second optical element are omitted, and the second optical element is omitted. The exit surface of the element and the entrance surface of the first optical element can be omitted.

The present invention includes an image display device configured to include the above optical system for the right eye or the left eye.

The present invention also includes an image display device comprising a pair of the above optical systems for the right eye and the left eye.

Further, the image display device includes an image display device having supporting means for supporting the observer's head so as to be located in front of the observer's face.

In the image display apparatus of the present invention, an image pickup device or an image pickup film is arranged at the position of the image display device by inverting the optical path, and object light is made to enter from the exit pupil side. It can also be configured as an optical system or an imaging device.

[0052]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments 1 to 3 of the optical system of the image display device according to the present invention will be described below. Although this embodiment will be described with reference to reverse ray tracing, it can be used as an image display device by arranging a reflective image display element on the image plane and arranging the pupil of the observer's eyeball at the pupil position. The configuration parameters of this embodiment will be described later.

In each embodiment, as shown in FIG. 1, the axial principal ray 2 exits the center of the object, passes through the center of the pupil 1, passes through the center of the display surface 5, and is reflected at the center of the display surface 5. , Light rays reaching the center of the light source surface 6. And the axial chief ray 2
Is defined as the origin of the optical surface constituting the optical system of the image display device, the direction along the axial principal ray 2 incident on the surface of the pupil 1 is defined as the positive Z-axis direction, And the plane including the image plane center as the YZ plane, passing through the origin and orthogonal to the YZ plane, the direction from the near side of the paper to the back side is defined as the positive X-axis direction, and the X-axis, Z-axis and right-hand orthogonal coordinates The axis constituting the system is the Y axis. FIG. 1 shows a coordinate system defined for the origin.

In the first to third embodiments, the surface is decentered in the YZ plane of the coordinate system defined for the center of the pupil 1, and the only symmetric surface of each rotationally asymmetric free-form surface is defined as Y −Z plane. For each eccentric surface, the amount of eccentricity (X, Y, and Z in the X-axis, Y-axis, and Z-axis directions) at the top of the surface from the origin of the coordinate system defined for the center of the pupil 1 and The center of the surface (the free-form surface is the Z-axis of the formula (a), and the aspheric surface is the Z-axis of the formula (b) described later) is centered on the X, Y, and Z axes. The inclination angles (α, β, γ (°), respectively) are given. In this case, the positive α and β mean counterclockwise with respect to the positive direction of each axis, and the positive γ means clockwise with respect to the positive direction of the Z axis.

In the case where a specific surface and a surface subsequent thereto constitute a coaxial optical system among the optically acting surfaces constituting the optical system of the embodiment, a surface interval is given, and in addition, a medium spacing is given. The refractive index and Abbe number are given according to a conventional method.

The shape of the surface of the free-form surface used in the present invention is defined by the above equation (a), and the Z-axis of the definition equation is the axis of the free-form surface.

The aspherical surface is a rotationally symmetric aspherical surface given by the following definition expression.

Z = (Y ² / R) / [1+ ｛1− (1 + K) Y ² / R ² ｝ ^1/2 ] + AY ⁴ + BY ⁶ + CY ⁸ + DY ¹⁰ +... (B) Is the optical axis (on-axis principal ray) where the traveling direction of light is positive, and Y is a direction perpendicular to the optical axis. Here, R is a paraxial radius of curvature, K is a conic constant, and A, B, C, D,... Are fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients, respectively.
The Z axis of this definition expression is the axis of the rotationally symmetric aspherical surface.

The term relating to a free-form surface or aspherical surface for which no data is described is zero. Regarding the refractive index,
The values for the d-line (wavelength 587.56 nm) are shown. The unit of the length is mm.

As another definition of the free-form surface, there is a Zernike polynomial given by the following expression (c).
The shape of this surface is defined by the following equation. The Z axis of the defining equation is the axis of the Zernike polynomial. The definition of the rotationally asymmetric surface is defined by polar coordinates of the height of the Z axis with respect to the XY plane, R is the distance from the Z axis in the XY plane, A is the azimuth around the Z axis, and the X axis It can be expressed by the rotation angle measured from.

X = R × cos (A) y = R × sin (A) Z = D ₂ + D ₃ R cos (A) + D ₄ R sin (A) + D ₅ R ² cos (2A) + D ₆ (R ² -1 ^{_{) + D 7 R 2 sin (}} 2A) + D 8 R 3 cos (3A) + D 9 (3R 3 -2R) cos (A) + D 10 (3R 3 -2R) sin (A) + D 11 R 3 sin (3A) + D ^{_{12 R 4 cos (4A) +}} D 13 (4R 4 -3R 2) cos (2A) + D 14 (6R 4 -6R 2 +1) + D 15 (4R 4 -3R 2) sin (2A) + D 16 R 4 sin (4A ^{_{) + D 17 R 5 cos (}} 5A) + D 18 (5R 5 -4R 3) cos (3A) + D 19 (10R 5 -12R 3 + 3R) cos (A) + D 20 (10R 5 -12R 3 + 3R) sin (A) ^{_{+ D 21 (5R 5 -4R 3}} ) sin (3A) + D 22 R 5 sin (5A) + D 23 R 6 cos (6A) + D 24 (6R 6 -5R 4) cos (4A) + D 25 (15R 6 -20R 4 ^{+ 6R 2) cos (2A)} + D 26 (20R 6 -30R 4 + 12R 2 -1) + D 27 (15R 6 -20R 4 + 6R 2) sin (2A) ^{_{D 28 (6R 6 -5R 4)}} sin (4A) + D 29 R 6 sin (6A) ····· ··· (c) In addition, to design an optical system symmetric with respect to the X-axis direction, D
_{4, D 5, D 6,} D 10 0, D 11, D 12, D 13, D 14, D
_20, D _21, D ₂₂ ... to use.

As another example, the following definition formula (d)
Is raised.

Z = ΣΣC _nm XY As an example, when k = 7 (seventh-order term) is considered, when expanded, it can be expressed by the following equation.

Z = C ₂ + C ₃ Y + C ₄ | X | + C ₅ Y ² + C ₆ Y | X | + C ₇ X ² + C ₈ Y ³ + C ₉ Y ² | X | + C ₁₀ YX ² + C ₁₁ | X ³ | + C ₁₂ Y ⁴ + C ₁₃ Y ³ | X | + C ₁₄ Y ² X ² + C ₁₅ Y | X ³ | + C ₁₆ X ⁴ + C ₁₇ Y ⁵ + C ₁₈ Y ⁴ | X | + C ₁₉ Y ³ X ² + C ₂₀ Y ² | X ^{_{3 | + C 21 YX 4 +}} C 22 | X 5 | + C 23 Y 6 + C 24 Y 5 | X | + C 25 Y 4 X 2 + C 26 Y 3 | X 3 | + C 27 Y 2 X 4 + C 28 Y | X 5 | ^{_{+ C 29 X 6 + C 30}} Y 7 + C 31 Y 6 | X | + C 32 Y 5 X 2 + C 33 Y 4 | X 3 | + C 34 Y 3 X 4 + C 35 Y 2 | X 5 | + C 36 YX 6 + C 37 | X ⁷ | (d) In the embodiment of the present invention, the surface shape is represented by a free-form surface using the above equation (a).
It goes without saying that the same operation and effect can be obtained by using the equation (d).

FIG. 1 is a YZ sectional view including the optical axis 2 according to the first embodiment of the present invention. The half angle of view of the observation optical system in this embodiment is 18 ° in the X direction and 11.5 ° in the Y direction, and the size of the reflective image display device is 11.5 × 7.2 mm.

In this embodiment, in the reverse ray tracing, the exit pupil 1, the decentered prisms 10, 20, and 3 are arranged in the order in which light passes from the object side.
Eyepiece optical system 3 composed of 0, light splitting surface 40 of a semi-transmissive reflecting surface
Light splitting element 4 provided with display, display surface 5 of reflective image display element
The light source surface 6 is disposed on the reflection side (illumination light incident side) of the light dividing surface 40 of the light dividing element 4, and a surface 7 conjugate to the exit pupil 1 is located.

The eccentric prism 10 of the eyepiece optical system 3 is composed of a first surface 11 to a third surface 13, and the first surface 11 allows a light beam from the object side to enter the prism 10 and the second surface 13.
The second surface 12 reflects the light beam reflected from the first surface 11 in the prism, and the third surface 13 reflects the light beam reflected from the first surface 11 into the prism. The first surface 11 is the same optically active surface having both a transmitting effect and a reflecting effect.

The eccentric prism 20 of the eyepiece optical system 3 is composed of a first surface 21 to a third surface 23. The first surface 21 allows the light beam from the eccentric prism 10 to enter the prism 20.
The second surface 22 is configured to reflect the light beam incident from the first surface 21 in the prism, and the third surface 23 is configured to emit the light beam reflected by the second surface 22 to the outside of the prism.

The eccentric prism 30 of the eyepiece optical system 3 is composed of a first surface 31 to a fourth surface 34. The first surface 31 allows the light beam from the eccentric prism 20 to enter the prism 30.
The second surface 32 reflects the light beam incident on the first surface 31 in the prism, and the third surface 33 intersects the light beam reflected on the second surface 32 with the light beam incident on the second surface 32 from the first surface 31. Thus, the light is reflected inside the prism, and the fourth surface 34 is configured to emit the light beam reflected by the third surface 33 to the outside of the prism.

The three decentered prisms 10 to 3
The ocular optical system 3 composed of an optical system 0 is a type of optical system that forms an intermediate image once by a relay optical system composed of an eccentric prism 30 and an eccentric prism 20. The intermediate image is a first surface of the eccentric prism 20. An image is formed near 21.

The light splitting element 4 comprises two transparent media 41 and 42
Are bonded to each other, and a light splitting surface 40 of a semi-transmissive reflecting surface is provided on the bonding surface. In the reverse ray tracing, the light passes through the light emitting surface 44, the light splitting surface 40, and the image display element facing surface 45. Then, the light reaches the display surface 5 of the reflection-type image display device via the cover glass 51 of the reflection-type image display device adhered to the image display device-facing surface 45, and the light beam reflected by the display surface 5 forms a cover glass. 51, the light passes through the image display element facing surface 45, is reflected by the light dividing surface 40, exits from the illumination light incident surface 43 of the light dividing element 4 to outside the prism, and reaches the light source surface 6. The image of the exit pupil 1 is formed on a surface 7 conjugate with the exit pupil 1 after the light source surface 6.

With such an arrangement, the illumination light from the light source surface 6 disposed closer to the light splitting element 4 than the surface 7 conjugate with the exit pupil 1 is irradiated by the illumination light incident surface of the light splitting element 4. 4
3 enters the joining prism member, is reflected by the light splitting surface 40, becomes a substantially parallel light beam, exits the joining prism member from the image display element facing surface 45, and passes through the cover glass 51 to display the reflective image display element. The surface 5 is illuminated almost vertically. The display light from the display surface 5 of the reflection type liquid crystal display element is transmitted through the cover glass 51 to the image display element facing surface 45 of the light splitting element 4.
From the light into the junction prism member.
Through the exit surface 44, exits the cemented prism member, enters the prism 30 from the fourth surface 34 of the decentered prism 30 of the eyepiece optical system 3, is internally reflected by the third surface 33, and is reflected by the second surface. 32, exits the prism 30 from the first surface 31, exits the prism 20 from the third surface 23 of the eccentric prism 20, and is internally reflected by the second surface 22 to form the first surface 21.
From the prism 20 to the third surface 1 of the prism 10
3, the light enters the prism 10, is totally reflected by the first surface 11, is reflected by the second surface 12, is then refracted by the first surface 11, exits the prism 10, and is observed at the position of the exit pupil 1. It enters the eyeball of the user and forms an enlarged image of the display image of the reflective liquid crystal display device.

The second to fifth surfaces of the constituent parameters described below are the prism 10, the sixth to eighth surfaces are the prisms 20, the ninth to twelfth surfaces are the prisms 30, The thirteenth to fourteenth surfaces are the light splitting elements 4 during image display, the fourteenth to fifteenth surfaces are the cover glass 51, the fifteenth surface is the display surface 5, and the first to the fifth surfaces.
The cover glass 51 extends from the fifth surface to the sixteenth surface.
Seventh surface is a light splitting surface 40 as a reflecting surface, eighteenth surface is an illumination light incident surface 43 of the light splitting element 4, nineteenth surface is a light source surface 6, and an image surface (20th surface) is emitted. Surface 7 conjugate with pupil 1. Each surface from the second surface to the image surface (the twentieth surface) is represented by the amount of eccentricity with respect to the center of the exit pupil 1 of the first surface.

FIG. 2 is a YZ sectional view including the optical axis 2 according to the second embodiment of the present invention. The half angle of view of the observation optical system of this embodiment is 16 ° in the X direction and 10.2 ° in the Y direction, and the size of the reflective image display device is 11.52 × 7.2 mm.

In this embodiment, in the reverse ray tracing, the exit pupil 1, the decentered prisms 10, 20, and 3 are arranged in the order in which light passes from the object side.
Eyepiece optical system 3 composed of 0, light splitting surface 40 of a semi-transmissive reflecting surface
And a display surface 5 of a reflective image display device. A light source surface 6 is provided on the reflection side (illumination light incident side) of the light division surface 40 of the light division device 4. A plane 7 that is arranged and conjugate to the exit pupil 1 is located.

Here, the wobbling element 8 is disclosed in
As shown in JP-A-36054, a phase modulation element and a birefringent medium are sequentially arranged, and the display surface 5 of the image display element is wobbled in one-dimensional direction or two-dimensional direction (pixel shift, pixel shift). ) To increase the resolution.
In the structural parameters described later, they are represented by parallel plates.

The eyepiece optical system 3 of this embodiment is the same as the eyepiece optical system 3 of the first embodiment.

The light splitting element 4 is composed of two transparent media 4
1 and 42 are bonded to each other, and are provided with a light splitting surface 40 of a semi-transmissive reflecting surface on the bonding surface. In the reverse ray tracing, the light emitting surface 44, the light splitting surface 40, and the image display element facing surface. 45, the wobbling element 8 adhered to the image display element facing surface 45 and the cover glass 51 of the reflection type image display element adhered to the opposite side of the wobbling element 8 to form a reflective image display element. The light flux reaching the display surface 5 and reflected by the display surface 5 is applied to the cover glass 51, the wobbling element 8, and the image display element facing surface 4.
5, is reflected by the light splitting surface 40, exits from the illumination light incident surface 43 of the light splitting element 4 to outside the prism, and reaches the light source surface 6. The image of the exit pupil 1 is formed on a surface 7 conjugate with the exit pupil 1 after the light source surface 6.

With such an arrangement, the illumination light from the light source surface 6 arranged closer to the light splitting element 4 than the surface 7 conjugate with the exit pupil 1 is irradiated by the illumination light incident surface of the light splitting element 4. 4
3, the light enters the junction prism member, is reflected by the light splitting surface 40, becomes a substantially parallel light beam, exits the junction prism member from the image display element facing surface 45, and is reflected through the wobbling element 8 and the cover glass 51. The display surface 5 of the image display device is illuminated substantially vertically. The display light from the display surface 5 of the reflection type liquid crystal display element enters the junction prism member from the image display element facing surface 45 of the light splitting element 4 via the cover glass 51 and the wobbling element 8, and this time the light splitting surface The light exits the cemented prism member from the exit surface 44 through the exit surface 40, enters the prism 30 from the fourth surface 34 of the decentered prism 30 of the eyepiece optical system 3, is internally reflected by the third surface 33, and Face 32
At the first surface 31, exits the prism 30 from the first surface 31, enters the prism 20 from the third surface 23 of the eccentric prism 20, internally reflects at the second surface 22, and exits the prism 20 from the first surface 21. And enters the prism 10 from the third surface 13 of the prism 10, is totally reflected by the first surface 11,
The light is reflected by the surface 12 and then refracted by the first surface 11 to exit the prism 10 and enter the observer's eyeball at the position of the exit pupil 1 to form an enlarged image of the display image of the reflective liquid crystal display device. I do.

The second to fifth surfaces of the constituent parameters described later are the prism 10, the sixth to eighth surfaces are the prisms 20, the ninth to twelfth surfaces are the prisms 30, The thirteenth to fourteenth surfaces are the light splitting elements 4 during image display, the fourteenth to fifteenth surfaces are wobbling elements 8, the fifteenth to sixteenth surfaces are cover glasses 51, The sixteenth surface is the display surface 5, the sixteenth to seventeenth surfaces are cover glasses 51, the seventeenth to eighteenth surfaces are wobbling elements 8,
The nineteenth surface is the light dividing surface 40 as a reflecting surface,
The surface is the illumination light incident surface 43 of the light splitting element 4, the twenty-first surface is the light source surface 6, and the image surface (the twenty-second surface) is the surface 7 conjugate with the exit pupil 1. Each surface from the second surface to the image surface (the twenty-second surface) is represented by the amount of eccentricity with respect to the center of the exit pupil 1 of the first surface.

FIG. 3 is a YZ sectional view including the optical axis 2 according to the third embodiment of the present invention. The half angle of view of the observation optical system of this embodiment is 18 ° in the X direction and 11.5 ° in the Y direction, and the size of the reflective image display device is 11.52 × 7.2 mm.

In this embodiment, the exit pupil 1, the decentered prisms 10, 20, 3 and
0, an eyepiece optical system 3, a wobbling element 8, a light splitting element 4 having a light splitting surface 40 of a transflective surface, and a display surface 5 of a reflection type image display element. A light source surface 6 is arranged on the reflection side (illumination light incident side) of the surface 40, and a surface 7 conjugate to the exit pupil 1 is located.

This embodiment is an example in which the wobbling element 8 is integrally bonded to the eyepiece optical system 3 side of the light splitting element 4 to prevent interface reflection.

The eyepiece optical system 3 of this embodiment is the same as the eyepiece optical system 3 of the first embodiment.

The light dividing element 4 is composed of two transparent media 4
1 and 42 are joined to each other, and are provided with a light splitting surface 40 of a semi-transmissive reflecting surface on the joint surface thereof, and a wobbling element 8 is adhered to an emission surface 44 of the light splitting element 4. In the reverse ray tracing, the cover glass 51 of the reflection type image display element which is transmitted through the wobbling element 8, the exit surface 44, the light dividing surface 40, and the image display element facing surface 45 and is adhered to the image display element facing surface 45 is removed. After that, the light reaches the display surface 5 of the reflection type image display device, and the light flux reflected by the display surface 5 is applied to the cover glass 51 and the image display device facing surface 4.
5, is reflected by the light splitting surface 40, exits from the illumination light incident surface 43 of the light splitting element 4 to outside the prism, and reaches the light source surface 6. The image of the exit pupil 1 is formed on a surface 7 conjugate with the exit pupil 1 after the light source surface 6.

With such an arrangement, the illumination light from the light source surface 6 disposed closer to the light splitting element 4 than the surface 7 conjugate with the exit pupil 1 is irradiated by the illumination light incident surface of the light splitting element 4. 4
3 enters the joining prism member, is reflected by the light splitting surface 40, becomes a substantially parallel light beam, exits the joining prism member from the image display element facing surface 45, and passes through the cover glass 51 to display the reflective image display element. The surface 5 is illuminated almost vertically. The display light from the display surface 5 of the reflection type liquid crystal display element is transmitted through the cover glass 51 to the image display element facing surface 45 of the light splitting element 4.
From the light into the junction prism member.
Through the exit surface 44 to exit the cemented prism member, pass through the wobbling element 8 and enter the prism 30 from the fourth surface 34 of the decentered prism 30 of the eyepiece optical system 3,
The light is internally reflected by the third surface 33, internally reflected by the second surface 32, and exits from the first surface 31 to the outside of the prism 30.
0 enters the prism 20 from the third surface 23 and the second surface 2
2, exits the prism 20 from the first surface 21, enters the prism 10 from the third surface 13 of the prism 10, is totally reflected by the first surface 11, is reflected by the second surface 12, and Are refracted by the first surface 11 and exit the prism 10 to enter the observer's eyeball at the position of the exit pupil 1 to form an enlarged image of the display image of the reflective liquid crystal display device.

The second to fifth surfaces of the constituent parameters described later are the prism 10, the sixth to eighth surfaces are the prisms 20, the ninth to twelfth surfaces are the prisms 30, The thirteenth to fourteenth surfaces are the wobbling elements 8, the fourteenth to fifteenth surfaces are the light splitting elements 4 for displaying an image, the fifteenth to sixteenth surfaces are the cover glass 51, The sixteenth surface is the display surface 5, the sixteenth to seventeenth surfaces are the cover glass 51, the eighteenth surface is the light splitting surface 40 as a reflection surface, and the nineteenth surface is the illumination of the light splitting element 4. The light incident surface 43, the twentieth surface is the light source surface 6, and the image surface (the twenty-first surface) is the surface 7 conjugate with the exit pupil 1. Each surface from the second surface to the image surface (the twenty-first surface) is represented by the amount of eccentricity with respect to the center of the exit pupil 1 of the first surface.

The following are the configuration parameters of the first to third embodiments. "FFS" in the following table is a free-form surface, "AS
S "indicates an aspherical surface. (Example 1) Surface number Curvature radius Surface interval Eccentricity Refractive index Abbe number Object plane ∞ -1250.00 1 ∞ (pupil) Eccentricity (1) 2 ASS Eccentricity (2) 1.4924 57.6 3 FFS Eccentricity ( 3) 1.4924 57.6 4 ASS Eccentricity (2) 1.4924 57.6 5 FFS Eccentricity (4) 6 ASS Eccentricity (5) 1.4924 57.6 7 ∞ Eccentricity (6) 1.4924 57.6 8 ASS Eccentricity (7) 9 FFS Eccentricity (8) 1.4924 57.6 10 FFS Eccentricity (9) 1.4924 57.6 11 FFS Eccentricity (10) 1.4924 57.6 12 FFS Eccentricity (11) 13 ∞ Eccentricity (12) 1.4924 57.6 14 ∞ Eccentricity (13) 1.5163 64.1 15 ∞ Eccentricity (14) 1.5163 64.1 16 ∞ Eccentricity (13) 1.4924 57.6 17 FFS eccentric (15) 1.4924 57.6 18 ∞ eccentricity (16) 19 ∞ eccentricity (17) image surface ∞ eccentricity (18) ASS R -55.44 K 2.1396 × 10 -1 A 3.9915 × 10 -6 B 2.2958 × 10 - ⁹ C -3.1207 × 10 ^-12 ASS R 18.43 K 7.4067 × 10 ^-1 A 5.3964 × 10 ^-5 B 1.0832 × 10 ^-6 C -9.4725 × 10 ^-9 ASS R 17.33 K -1.7782 A -5.5187 × 10 ^-5 B -1.2987 × 10 ^-7 C -7.8713 × 10 ^-9 FFS _{^{C 4 -1.3856 × 10 -2 C 6}} -1.3735 × 10 -2 C 8 -1.0414 × 10 -6 C 10 3.2479 × 10 -5 C 11 -2.2932 × 10 -6 C 13 -5.0980 × 10 -6 C 15 - 2.9220 × 10 ^-6 C ₁₇ -1.3012 × 10 ^-9 C ₁₉ -2.0877 × 10 ^-8 C ₂₁ 1.0984 × 10 ^-7 FFS C ₄ 2.2988 × 10 ^-2 C ₆ 8.7 785 × 10 ^-3 C ₈ 5.5743 × 10 ^-4 C ₁₀ 4.1097 × 10 ^-4 C ₁₁ 2.4130 × 10 ^-4 C ₁₃ 7.6633 × 10 ^-4 C ₁₅ -7.3274 × 10 ^-7 C ₁₇ 3.4372 × 10 ^-6 C ₁₉ -3.1331 × 10 ^-5 C ₂₁ -4.0687 × 10 _{^{-7 FFS C 4 -5.4349 × 10 -3}} C 6 -1.6790 × 10 -2 C 8 -1.9228 × 10 -3 C 10 -1.4828 × 10 -3 C 11 -8.2821 × 10 -5 C 13 -2.9887 × 10 - ⁴ C ₁₅ -1.6176 × 10 ^-4 C ₁₇ -9.8905 × 10 ^-6 C ₁₉ -1.7842 × 10 ^-5 C ₂₁ -7.3258 × 10 ^-6 FFS C ₄ 3.9701 × 10 ^-3 C ₆ 2.9 194 × 10 ^-3 C ₈ -5.4333 × 10 ^-5 C ₁₀ 1.9408 × 10 ^-4 C ₁₁ -1.4270 × 10 ^-6 C ₁₃ -1.1644 × 10 ^-5 C ₁₅ -9.9238 × 10 ^-6 C ₁₇ -6.3749 × 10 ^-7 C ₁₉ -1.1090 × 10 ^-6 C ₂₁ -8.1133 × 10 ^-7 FFS C ₄ -1.2730 × 10 ^-2 C ₆ -1.0195 × 10 ^-2 C ₈ -1.0071 × 10 ^-4 C ₁₀ 1.5580 × 10 ^-4 C ₁₁ 2.7477 × 10 ^-6 C ₁₃ 1.2945 × 10 ^-5 C ₁₅ 1.0149 × 10 ^-5 C ₁₇ -5.9775 × 10 ^-7 C ₁₉ -5.9311 × 10 ^-7 C ₂₁ 2.1818 × 10 ^-7 FFS C ₄ 5.4121 × 10 ^-3 C ₆ 2.4681 × 10 ^-2 C ₈ -2.2435 × 10 ^-3 C ₁₀ -5.2114 × 10 ^-4 C ₁₁ 2.3590 × 10 ^-5 C ₁₃ 1.3835 × 10 ^-4 C ₁₅ 2.4701 × 10 ^-4 C ₁₇ -6.3268 × 10 ^-8 C ₁₉ 2.9 510 × 10 ^-5 C ₂₁ 2.5078 × 10 ^-6 FFS C ₄ -2.2874 × 10 ^-2 C ₆ -1.5515 × 10 ^-2 C ₈ 6.0651 × 10 ^-4 C ₁₀ 2.6796 × 10 ^-4 C ₁₁ -3.0974 × 10 ^-5 C ₁₃ 2.3913 × 10 ^-5 C ₁₅ -3.7454 × 10 ^-5 C ₁₇ -5.8534 × 10 ^-6 C ₁₉ -4.5885 × 10 ^-6 C ₂₁ -3.4778 × 10 ^-6 Eccentricity (1) X 0.00 Y 0.00 Z 0.00 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 9.36 Z 30.67 α 12.82 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -0.89 Z 39.29 α -23.24 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 14.24 Z 35.02 α 68.23 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 16.56 Z 35.83 α 83.43 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y 24.62 Z 36.31 α 125.50 β 0.00 γ 0.00 Eccentricity (7) X 0.00 Y 23.36 Z 44.53 α 176.05 β 0.00 γ 0.00 Heart (8) X 0.00 Y 22.40 Z 45.39 α 174.59 β 0.00 γ 0.00 Eccentricity (9) X 0.00 Y 23.87 Z 58.07 α 153.85 β 0.00 γ 0.00 Eccentricity (10) X 0.00 Y 32.07 Z 52.58 α 108.38 β 0.00 γ 0.00 Eccentricity 11) X 0.00 Y 18.76 Z 51.08 α 89.86 β 0.00 γ 0.00 eccentricity (12) X 0.00 Y 17.76 Z 50.70 α 89.58 β 0.00 γ 0.00 eccentricity (13) X 0.00Y 7.76 Z 50.62 α 89.58 β 0.00 γ eccentricity (14) X 0.00 Y 4.48 Z 50.60 α 89.58 β 0.00 γ 0.00 Eccentricity (15) X 0.00 Y 13.86 Z 50.67 α 125.47 β 0.00 γ 0.00 Eccentricity (16) X 0.00 Y 11.73 Z 56.98 α 169.38 β 0.00 γ 0.00 Eccentricity (17) X 0.00 Y 11.04 Z 58.73 α 154.38 β 0.00 γ 0.00 Eccentricity (18) X 0.00 Y 10.78 Z 62.02 α 169.38 β 0.00 γ 0.00.

(Example 2) Surface number Curvature radius Surface distance Eccentricity Refractive index Abbe number Object plane ∞-1000.00 1 ∞ (pupil) Eccentricity (1) 2 ASS Eccentricity (2) 1.4924 57.6 3 FFS Eccentricity (3) 1.4924 57.6 4 ASS Eccentricity (2) 1.4924 57.6 5 FFS Eccentricity (4) 6 -470.07 Eccentricity (5) 1.4924 57.6 7 ∞ Eccentricity (6) 1.4924 57.6 8 18.57 Eccentricity (7) 9 FFS Eccentricity (8) 1.4924 57.6 10 FFS Eccentricity (9) 1.4924 57.6 11 FFS Eccentricity (10) 1.4924 57.6 12 FFS Eccentricity (11) 13 ∞ Eccentricity (12) 1.4924 57.6 14 ∞ Eccentricity (13) 1.5163 64.1 15 ∞ Eccentricity (14) 1.5163 64.1 16 ∞ Eccentricity (15) 1.5163 64.1 17 ∞ Eccentricity (14) 1.5163 64.1 18 ∞ Eccentricity (13) 1.4924 57.6 19 FFS Eccentricity (16) 1.4924 57.6 20 ∞ Eccentricity (17) 21 ∞ Eccentricity (18) Image plane ∞ Eccentricity (19) ASS R -51.67 K 2.4332 A -8.3613 × 10 ^-7 B 2.3570 × 10 ^-8 C -1.8757 × 10 ^-11 FFS C ₄ -1.4290 × 10 ^-2 C ₆ -1.4176 × 10 ^-2 C ₈ 1.7920 × 10 ^-5 C ₁₀ 4.7202 × 10 ^-5 C ₁₁ -2.7695 × 10 ^-6 C ₁₃ -6.0900 × 10 ^-6 C ₁₅ -3.8163 × 10 ^-6 C ₁₇ -2.1081 × 10 ^-8 C ₁₉ 4.1648 × 10 ^-8 C ₂₁ 1.2537 × 10 ^-7 FFS C ₄ -7.3719 × 10 ^-3 C ₆ -3.5314 × 10 ^-2 C ₈ 8.0476 × 10 ^-4 C ₁₀ -2.2967 × 10 ^-3 C ₁₁ 2.7243 × 10 ^-5 C ₁₃ 3.1563 × 10 ^-4 C ₁₅ 2.6656 × 10 ^-4 C ₁₇ -8.8980 × 10 ^-7 C ₁₉ -5.4431 × 10 ^-6 C ₂₁ 1.9723 × 10 ^-6 FFS C ₄ -1.0090 × 10 ^-2 C ₆ -3.3258 × 10 ^-2 C ₈ -5.3117 × 10 ^-4 C ₁₀ -6.2650 × 10 ^-4 C ₁₁ -1.1787 × 10 ^-5 C ₁₃ -1.0121 × 10 ^-4 C ₁₅ -1.0925 × 10 ^-4 C ₁₇ -7.2895 × 10 ^-6 C ₁₉ -2.1049 × 10 ^-5 C ₂₁ -1.9030 × 10 ^-5 FFS C ₄ 2.0590 × 10 ^-3 C ₆ -3.0456 × 10 ^-3 C ₈ 2.6221 × 10 ^-4 C ₁₀ 2.9679 × 10 ^-4 C ₁₁ -2.3378 × 10 ^-6 C ₁₃ -3.1006 × 10 ^-6 C ₁₅ 1.0119 × 10 ^-5 C ₁₇ -6.1910 × 10 ^-7 C ₁₉ -3.9797 × 10 ^{-6 _{C 21 -2.9181 × 10 -6 FFS C}} 4 -1.4942 × 10 -2 C 6 -1.4187 × 10 -2 C 8 6.1858 × 10 -5 C 10 2.1856 × 10 -4 C 11 -8.7827 × 10 -7 C 13 - 2.8865 × 10 ^-6 C ₁₅ 4.0624 × 10 ^-6 C ₁₇ -4.3 121 × 10 ^-7 C ₁₉ -1.2927 × 10 ^-6 C ₂₁ -9.1384 × 10 ^-7 FFS C ₄ -4.0255 × 10 ^-3 C ₆ 2.1274 × 10 ^-2 C ₈ -2.6 302 × 10 ^-3 C ₁₀ -3.3418 × 10 ^-3 C ₁₁ 1.0966 × 10 ^-5 C ₁₃ 1.5588 × 10 ^-4 C ₁₅ 4.1184 × 10 ^-4 C ₁₇ -1.7475 × 10 ^{-5 _{C 19 -1.8305 × 10 -5 C 21}} -2.1189 × 10 -5 FFS C 4 -2.7168 × 10 -2 C 6 -1.7403 × 10 -2 C 8 3.3242 × 10 -4 C 10 1.8083 × 10 -4 C 11 - 4.2453 × 10 ^-5 C ₁₃ 2.1 203 × 10 ^-5 C ₁₅ -3.4762 × 10 ^-5 C ₁₇ -5.2645 × 10 ^-6 C ₁₉ 6.0649 × 10 ^-8 C ₂₁ -7.7514 × 10 ^-7 Eccentricity (1) X 0.00 Y 0.00 Z 0.00 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 8.95 Z 30.66 α 13.61 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y 0.37 Z 39.39 α -20.44 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 14.51 Z 35.09 α 50.13 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 16.94 Z 36.49 α 80.10 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y 22.80 Z 35.93 α 129.49 β 0.00 γ 0.00 Eccentricity (7) X 0.00 Y 25.00 Z 41.92 α -165.94 β 0.00 γ 0.00 Eccentricity (8) X 0.00 Y 21.30 Z 43.60 α 179.91 β 0.00 γ 0.00 Eccentricity (9) X 0.00 Y 24.45 Z 57.19 α 151.80 β 0.00 γ 0.00 Eccentricity (10) X 0.00 Y 30.18 Z 52.34 α 104.83 β 0.00 γ 0.00 Eccentricity (11) X 0.00 Y 16.67 Z 52.53 α 88.31 β 0.00 γ 0.00 Eccentricity (12) X 0.00 Y 14.89 Z 50.48 α 88.35 β 0.00 γ 0.00 Eccentricity (13) X 0.00 Y 4.90 Z 50.19 α 88.35 β 0.00 γ 0.00 Eccentricity (14) X 0.00 Y 3.20 Z 50.14 α 88.35 β 0.00 γ 0.00 Eccentricity (15) X 0.00 Y 1.62 Z 50.10 α 88.35 β 0.00 γ 0.00 Eccentricity (16) X 0.00Y 11.39 Z 50.38 α 124.25 β 0.00 γ 0.00 Eccentricity (17) X 0.00 Y 9.12 Z 56.68 α 173.24 β 0.00 γ 0.00 Eccentricity (18) X 0.00 Y 8.94 Z 58.17 α 153.24 β 0.00 γ 0.00 Eccentricity (19) X 0.00 Y 8.76 Z 59.66 α 173.24 β 0.00 γ 0.00.

Example 3 Surface Number Curvature Radius Surface Distance Eccentricity Refractive Index Abbe Number Object Surface ∞ -1000.00 1 ∞ (pupil) Eccentricity (1) 2 ASS Eccentricity (2) 1.4924 57.6 3 FFS Eccentricity (3) 1.4924 57.6 4 ASS Eccentricity (2) 1.4924 57.6 5 FFS Eccentricity (4) 6 38.63 Eccentricity (5) 1.4924 57.6 7 ∞ Eccentricity (6) 1.4924 57.6 8 17.96 Eccentricity (7) 9 FFS Eccentricity (8) 1.4924 57.6 10 FFS Eccentricity (9) 1.4924 57.6 11 FFS eccentricity (10) 1.4924 57.6 12 FFS eccentricity (11) 13 ∞ eccentricity (12) 1.5163 64.1 14 ∞ eccentricity (13) 1.4924 57.6 15 ∞ eccentricity (14) 1.5163 64.1 16 ∞ eccentricity (15) 1.5163 64.1 17 ∞ eccentricity (14) 1.4924 57.6 18 FFS Eccentricity (16) 1.4924 57.6 19 ∞ Eccentricity (17) 20 ∞ Eccentricity (18) Image plane ∞ Eccentricity (19) ASS R -49.38 K 7.3241 × 10 ^-1 A -4.5432 × 10 ^-6 B ^{2.1489 × 10 -8 C -1.5676 × 10} -11 FFS C 4 -1.4755 × 10 -2 C 6 -1.4222 × 10 -2 C 8 2.1241 × 10 -5 C 10 6.9832 × 10 -5 C 11 -3.4264 × 10 - ⁶ C ₁₃ -7.9043 × 10 ^-6 C ₁₅ -5.2511 × 10 ^-6 C ₁₇ -1.5242 × 10 ^-8 C ₁₉ 6.2794 × 10 ^-8 C ₂₁ 1.3664 × 10 ^-7 FFS C ₄ 7.0756 × 10 ^-3 C ₆ -3.0049 × 10 ^-2 C ₈ 2.4938 × 10 ^-3 C ₁₀ 3.3990 × 10 ^-4 C ₁₁ -1.6790 × 10 ^-5 C ₁₃ 3.6129 × 10 ^-4 C ₁₅ 2.7244 × 10 ^-4 C ₁₇ -5.5578 × 10 ^-6 C ₁₉ -1.4474 × 10 ^-5 C ₂₁ -1.8818 × 10 ^-5 FFS C ₄ -4.0931 × 10 ^-3 C ₆ -3.3939 × 10 ^-2 C ₈ -8.9423 × 10 ^-4 C ₁₀ -8.0161 × 10 ^-4 C ₁₁ 1.0380 × 10 ^-5 C ₁₃ -1.0052 × 10 ^-4 C ₁₅ -1.4063 × 10 ^-4 C ₁₇ -6.0799 × 10 ^-6 C ₁₉ -1.8472 × 10 ^-5 C ₂₁ -1.7630 × 10 ^-5 FFS C ₄ 2.6279 × 10 ^-3 C ₆ -5.1566 × 10 ^-3 C ₈ 1.9361 × 10 ^-4 C ₁₀ 4.0746 × 10 ^-4 C ₁₁ -1.7992 × 10 ^-7 C ₁₃ -5.6199 × 10 ^-6 C ₁₅ -1.5344 × 10 ^-7 C ₁₇ -3.1243 × 10 ^-7 C ₁₉ -4.9444 × 10 ^-6 C ₂₁ -4.0163 × 10 ^-6 FFS C ₄ -1.4303 × 10 ^-2 C ₆ -1.5096 × 10 ^-2 C ₈ 4.7954 × 10 ^-5 C ₁₀ 2.6 118 × 10 ^-4 C ₁₁ 2.5974 × 10 ^-7 C ₁₃ 5.1685 × 10 ^-6 C ₁₅ 7.2799 × 10 ^-6 C ₁₇ -1.1364 × 10 ^-7 C ₁₉ -7.3233 × 10 ^-7 C ₂₁ -8.9366 × 10 ^-8 FFS C ₄ -3.8916 × 10 ^-3 C ₆ 3.3438 × 10 ^-2 C ₈ -9.4525 × 10 ^-4 C ₁₀ -2.3903 × 10 ^-3 C ₁₁ 5.1305 × 10 ^-5 C ₁₃ 1.7649 × 10 ^-4 C ₁₅ 1.6419 × 10 ^-4 C ₁₇ -4.4288 × 10 ^-6 C ₁₉ -4.9533 × 10 ^-6 C ₂₁ 6.4161 × 10 ^-6 FFS C ₄ -2.6649 × 10 ^-2 C ₆ -1.7207 × 10 ^-2 C ₈ 6.5022 × 10 ^-4 C ₁₀ 4.0 120 × 10 ^-4 C ₁₁ -4.3523 × 10 ^-5 C ₁₃ 2.4539 × 10 ^-5 C ₁₅ -3.5081 × 10 ^-5 C ₁₇ -6.6101 × 10 ^-6 C ₁₉ -1.3642 × 10 ^-6 C ₂₁ -1.9252 × 10 ^-6 Eccentricity (1) X 0.00 Y 0.00 Z 0.00 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 9.33 Z 30.86 α 12.62 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y 0.63 Z 39.36 α -20.96 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 14.81 Z 35.78 α 52.39 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 17.97 Z 33.43 α 74.78 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y 23.85 Z 37.23 α 124.04 β 0.00 γ 0.00 Eccentricity (7) X 0.00 Y 24.60 Z 44.19 α -177.49 β 0.00 γ 0.00 Eccentricity ( 8) X 0.00 Y 21.12 Z 45.44 α 170.38 β 0.00 γ 0.00 Eccentricity (9) X 0.00 Y 21.31 Z 58.89 Eccentricity (10) X 0.00 Y 28.58 Z 55.37 α 97.73 β 0.00 γ 0.00 Eccentricity Center (11) X 0.00 Y 15.06 Z 53.03 α 79.22 β 0.00 γ 0.00 Eccentricity (12) X 0.00 Y 14.26 Z 51.91 α 82.00 β 0.00 γ 0.00 Eccentricity (13) X 0.00 Y 12.58 Z 51.68 α 82.00 β 0.00 γ 0.00 Eccentricity 14) X 0.00 Y 2.67 Z 50.29 α 82.00 β 0.00 γ 0.00 Eccentricity (15) X 0.00 Y 1.11 Z 50.07 α 82.00 β 0.00 γ 0.00 Eccentricity (16) X 0.00 Y 9.11 Z 51.19 α 117.90 β 0.00 γ 0.00 Eccentricity (17) X 0.00 Y 6.15 Z 57.20 α 164.00 β 0.00 γ 0.00 Eccentricity (18) X 0.00 Y 5.65 Z 58.93 α 149.00 β 0.00 γ 0.00 Eccentricity (19) X 0.00 Y 5.32 Z 60.08 α 164.00 β 0.00 γ 0.00.

The lateral aberrations of Examples 1 to 3 are shown in FIG.
6 to FIG. In these lateral aberration diagrams, the numbers in parentheses indicate (horizontal angle of view, vertical angle of view), and indicate the lateral aberration at that angle of view.

By the way, the single eccentric prism 10 constituting the eyepiece optical system of the image display apparatus of the present invention of the above embodiment is described.
The number of prisms to 30 is not limited to the number of times of internal reflection of one or two times in the above embodiment, and various decentered prisms can be used. 8 to 11 show examples thereof. Note that description will be given of the reverse ray tracing.

In the case of FIG. 8, the prism P is
2, the second surface 113, the third surface 114, and the fourth surface 115. Light incident through the pupil 111 is refracted by the first surface 112, enters the prism P, and is internally reflected by the second surface 113. Then, the light is internally reflected by the third surface 114, is incident on the fourth surface 115, is refracted, and forms an image on the image surface 116.

In the case of FIG. 9, the prism P is
2, the second surface 113, the third surface 114, and the fourth surface 115. Light incident through the pupil 111 is refracted by the first surface 112, enters the prism P, and is internally reflected by the second surface 113. Then, the light enters the first surface 112 again, is totally reflected this time, and
The light is internally reflected by the surface 114, is incident on the fourth surface 115, is refracted, and forms an image on the image surface 116.

In the case of FIG. 10, the prism P is
The light incident through the pupil 111 is refracted by the first surface 112 and enters the prism P, is internally reflected by the second surface 113, and is reflected by the third surface 113. 114
Internally reflected again, is incident on the first surface 112 again and is now totally reflected, is again incident on the second surface 113 and is now refracted,
An image is formed on the image plane 116.

In the case of FIG. 11, the prism P is
2, the second surface 113, the third surface 114, and the fourth surface 115. Light incident through the pupil 111 is refracted by the first surface 112, enters the prism P, and is internally reflected by the second surface 113. Then, the light enters the third surface 114 and is internally reflected, and the second surface 113
Again, is internally reflected, enters the fourth surface 115, is refracted, and forms an image on the image surface 116.

The image display device according to the present invention as described above can be used, for example, as a head-mounted image display device. An example is shown below.

First, FIG. 12 shows a state in which the head-mounted image display device for binocular mounting is mounted on the observer's head, and FIG. 13 is a sectional view thereof. In this configuration, the optical system according to the present invention is used as a display optical system 100 as shown in FIG. 13 (the optical system of the first embodiment is used), and the display optical system 100 and a reflective image display are used. A portable image display device 1 such as a stationary or head-mounted image display device that can be observed with both eyes by preparing a pair of left and right pairs of elements 101 and supporting them at a distance from each other.
02.

That is, the display device main body 102 uses the above-described display optical system 100 as an observation optical system, and includes a pair of left and right display optical systems 100 corresponding to the display optical system 100. A reflective image display element 101 composed of a liquid crystal display element is arranged. Then, as shown in FIG. 12, the display device main body 102 is provided with a temporal frame 103 as shown in FIG. 12 so that the display device main body 102 can be held in front of the observer. . The eyepiece optical system 100 of each image display device 102
In order to protect the first surface 11 (FIG. 2) of the prism 10, a cover member 91 is arranged between the exit pupil of the eyepiece optical system 100 and the first surface 11, as shown in FIG. As the cover member 91, any of a parallel plane plate, a positive lens, and a negative lens may be used.

The speaker 1 is provided on the temporal frame 103.
04 is provided so that stereophonic sound can be heard together with image observation. Thus, the speaker 1
Since the playback device 106 such as a portable video cassette is connected to the display device main body 102 having the video signal 04 via the video / audio transmission code 105, the observer can attach the playback device 106 to an arbitrary portion such as a belt as shown in the figure. , So that the user can enjoy video and audio. Reference numeral 107 in FIG.
It is an adjustment unit for volume and the like. The display device main body 10
2, electronic components such as a video processing circuit and an audio processing circuit are incorporated.

Note that the cord 105 may have a jack at the tip so that it can be attached to an existing video deck or the like. Furthermore, it is connected to a tuner for TV radio wave reception,
It may be used for viewing, or may be connected to a computer to receive computer graphics images, message images from the computer, and the like. Also, in order to reject an obstructive code, an antenna may be connected to receive an external signal by radio waves.

Further, the display optical system according to the present invention may be used in a head mounted image display device for one eye in which an eyepiece optical system is disposed in front of one of the right and left eyes. FIG. 14 shows a state in which the image display device for one eye is mounted on the observer's head (in this case, mounted on the left eye). In this configuration, the display device main body 102, which is a combination of the display optical system 100 and the reflective image display element 101, is attached to the front frame 108.
The front frame 108 is provided with a temporal frame 103 as shown in the figure in the front frame 108 continuously to the left and right so that the display device main body 102 can be held in front of one eye of the observer. It has become. Other configurations are the same as those in FIG. 12, and a description thereof will be omitted.

The above-described image display device of the present invention can be configured, for example, as follows.

[1] An image display comprising an image display element and an eyepiece optical system having an overall positive power for projecting an image displayed on the image display element to an observer's eyeball and forming an exit pupil. In the apparatus, the eyepiece optical system includes at least one reflecting surface in the order of backward ray tracing from the exit pupil to the image display element, and a first optical path that bends an optical path laterally with respect to a visual axis of an observer. An optical element, comprising at least one reflecting surface, a second optical element for bending an optical path bent sideways by the first optical element in a direction away from an observer, and at least one reflecting surface, A third optical element for bending an optical path bent in a direction away from an observer by the second optical element in a direction substantially opposite to a direction bent by the first optical element;
The optical element and the third optical element constitute a relay optical system for an image displayed on the image display element, and at least the first optical element and the third optical element have positive power. Image display device.

[2] When the optical axis is defined by a ray passing through the center of the exit pupil and passing through the center of the image display element, the intermediate image position on the optical axis of the image displayed on the image display element is The above-mentioned 1 is characterized by being located between a reflection surface closest to the second optical element on an optical path of the first optical element and a reflection surface closest to the first optical element on an optical path of the second optical element. The image display device as described in the above.

[3] When the optical axis is defined by a light ray passing through the center of the exit pupil and passing through the center of the image display element, the light and the reflection surface closest to the second optical element on the optical path of the first optical element. An intersection with an axis, a straight line connecting an intersection of an optical axis with a reflection surface closest to the first optical element on an optical path of the second optical element, and an image display element on an optical path of the third optical element. When the angle between the closest intersection between the reflection surface and the optical axis and the straight line connecting the intersection between the image display element and the optical axis is θ, 100 ° <θ <200 ° (1) 3. The image display device according to the above item 1 or 2, wherein

[4] At least one of the first optical elements
4. The image display device according to any one of claims 1 to 3, wherein the two reflection surfaces are formed in a rotationally asymmetric curved surface shape giving positive power.

[5] At least one of the third optical elements
The image display device according to any one of claims 1 to 4, wherein the two reflection surfaces are formed in a rotationally asymmetric curved surface shape giving positive power.

[6] At least one of the first optical elements
Any one of the above items 1 to 5, wherein the two refracting surfaces are formed in a rotationally asymmetric curved surface shape having power.
An image display device according to the item.

[7] At least one of the third optical elements
Any one of the above items 1 to 6, wherein the two refracting surfaces are formed in a rotationally asymmetric curved surface shape having power.
An image display device according to the item.

[8] At least one of the second optical elements
Any one of the above items 1 to 7, wherein the two refracting surfaces are formed in a rotationally asymmetric curved surface shape having power.
An image display device according to the item.

[0112]

[9] When the magnification of the relay optical system is M, the following expression is satisfied: 0.5 <M <2.0 (2) apparatus.

[10] The third optical element has a refraction surface closest to the image display element side, and a distance between the refraction surface and the image display surface of the image display element is WD. When the diagonal length of the image display surface is D, 0.8 <WD / D <1.5 (3) is satisfied. apparatus.

[11] The first optical element is composed of a prism member formed of a medium having a refractive index (n) larger than 1 (n> 1), and the light beam emitted from the second optical element is transmitted through the prism. 11. An incident surface which is incident on the prism, at least one reflection surface which reflects the light beam inside the prism, and an exit surface which emits the light beam out of the prism. Image display device.

[12] The second optical element is composed of a prism member formed of a medium having a refractive index (n) greater than 1 (n> 1), and converts the light beam emitted from the third optical element into a prism. Any one of the above items 1 to 11, characterized in that it has an incident surface that enters the inside of the prism, at least one reflection surface that reflects the light beam inside the prism, and an exit surface that emits the light beam outside the prism. The image display device as described in the above.

[13] The second optical element is composed of a prism member formed of a medium having a refractive index (n) greater than 1 (n> 1), and the light beam emitted from the image display element is put into the prism. The light-receiving device according to any one of the above items 1 to 12, further comprising an incident surface on which the light enters, at least one reflecting surface for reflecting the light beam inside the prism, and an exit surface for emitting the light beam outside the prism. Image display device.

[14] The prism member of the first optical element reflects the light beam emitted from the second optical element into the prism and reflects the light beam reflected from the emission surface into the prism. 12. The image display device according to claim 11, wherein the image display device comprises: a surface; and an exit surface that reflects a light beam incident into the prism from the incident surface and emits the light beam reflected by the reflection surface to outside the prism.

[15] The prism member of the third optical element has an incident surface on which the light beam emitted from the image display element enters the prism, and a prism member for reflecting the light beam incident on the prism from the incident surface. A first reflection surface, a second reflection surface for reflecting the light beam reflected by the first reflection surface, and an emission surface for emitting the light beam reflected by the second reflection surface to the outside of the prism; 13. The image display device according to claim 12, wherein an axial principal ray incident on a surface and an axial principal ray reflected from the second reflecting surface intersect in the prism member.

[16] The prism member of the second optical element reflects an incident surface on which the light beam emitted from the third optical element enters the prism, and reflects the light beam incident on the prism from the incident surface. 14. The image display device according to the above 13, wherein the image display device comprises a reflection surface, and an emission surface for emitting the light beam reflected by the reflection surface to the outside of the prism.

[17] The second optical element and the third optical element are formed of an integral prism member, and the exit surface of the third optical element and the incident surface of the second optical element are omitted. The image display device according to any one of the above 11 to 16, wherein

[18] The first optical element and the second optical element are formed of an integral prism member, and the exit surface of the second optical element and the entrance surface of the first optical element are omitted. The image display device according to any one of the above 11 to 16, wherein

[19] The first optical element, the second optical element, and the third optical element are formed of an integral prism member, and the exit surface of the third optical element and the incident surface of the second optical element are omitted. 17. The image display device according to any one of claims 11 to 16, wherein an emission surface of the second optical element and an incidence surface of the first optical element are omitted.

[0123]

As is apparent from the above description, according to the present invention, it is possible to provide an image display apparatus having an eyepiece optical system which is small, has a wide angle of view, has a high performance, and can secure a long working distance. In particular, a head-mounted display capable of observing a bright image of a display element of a type that displays an image by reflected light such as a reflection type liquid crystal display element through an eyepiece optical system that is small, has a wide angle of view, and minimizes light loss. And the like can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical system of an image display device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of an optical system of an image display device according to a second embodiment of the present invention.

FIG. 3 is a sectional view of an optical system of an image display device according to a third embodiment of the present invention.

FIG. 4 is a diagram showing the lateral aberration of the first embodiment.

FIG. 5 is a diagram showing lateral aberrations in Example 2.

FIG. 6 is a diagram showing the lateral aberration of the third embodiment.

FIG. 7 is a diagram for explaining an intersection, a direction, a definition of a parameter θ, and the like between an optical surface and an axial principal ray.

FIG. 8 is a diagram showing an example of an eccentric prism applicable to the prism of the eyepiece optical system of the image display device of the present invention.

FIG. 9 is a diagram showing another example of the eccentric prism applicable to the prism of the eyepiece optical system of the image display device of the present invention.

FIG. 10 is a diagram showing another example of the eccentric prism applicable to the prism of the eyepiece optical system of the image display device of the present invention.

FIG. 11 is a diagram showing another example of the eccentric prism applicable to the prism of the eyepiece optical system of the image display device of the present invention.

FIG. 12 is a diagram showing a state in which the head-mounted image display device for binocular mounting according to the present invention is mounted on the observer's head.

FIG. 13 is a sectional view of FIG.

FIG. 14 is a diagram showing a state in which the head-mounted image display device for one-eye mounting according to the present invention is mounted on the observer's head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Exit pupil 2 ... On-axis chief ray (optical axis) 3 ... Eyepiece optical system 4 ... Light splitting element 5 ... Display surface 6 ... Light source surface 7 ... Surface (entrance pupil) conjugate to the exit pupil 8 ... Wobbling element 10, 20, 30 ... decentered prism 11, 21, 31 ... first surface 12, 22, 32 ... second surface 13, 23, 33 ... third surface 34 ... fourth surface 40 ... light dividing surface (semi-transmissive reflecting surface) 41 Reference numerals 42, transparent medium 43, illumination light incident surface 44, emission surface 45, image display element facing surface 51, cover glass 91, cover member 100, display optical system 101, reflective image display element 102, image display device (display) 103. Temporal frame 104. Speaker 105. Video and audio transmission code 106. Reproducing device 107. Adjusting unit 108. Previous frame 111. Pupil 112. First surface 113. Second surface 114. Third surface 115. 4 sides 11 6 ... Image plane P ... Eccentric prism

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/1335 G02F 1/1335 H04N 5/64 511 H04N 5/64 511A F-term (Reference) 2H087 KA07 KA24 LA12 RA06 RA45 TA01 TA02 TA05 TA06 2H088 EA10 HA21 HA23 HA28 MA07 2H091 FA14Z FA21X FA41X LA19 MA02

Claims (3)

[Claims] 1. An image display apparatus comprising: an image display element; and an eyepiece optical system having an overall positive power for projecting an image displayed on the image display element to an observer's eyeball and forming an exit pupil. In the first, the eyepiece optical system includes at least one reflecting surface in the order of backward ray tracing from the exit pupil toward the image display element, and the first eyepiece optical path is bent laterally with respect to a visual axis of an observer.
An optical element, at least one reflecting surface,
A second optical element that bends the optical path bent sideways by the optical element in a direction away from the observer, and an optical path that includes at least one reflecting surface and is bent by the second optical element in a direction away from the observer A third optical element that bends in a direction substantially opposite to the direction bent by the first optical element, wherein the second optical element and the third optical element are relays of an image displayed on the image display element. An image display device comprising an optical system, wherein at least the first optical element and the third optical element have a positive power. 2. When an optical axis is defined by a light ray passing through the center of the exit pupil and passing through the center of the image display element, an intermediate image position on the optical axis of an image displayed on the image display element is defined by the second position. 2. The optical device according to claim 1, wherein the reflective surface is located between a reflective surface closest to the second optical element on an optical path of one optical element and a reflective surface closest to the first optical element on an optical path of the second optical element. 3. The image display device as described in the above. 3. An optical axis defined by a light beam passing through the center of the exit pupil and passing through the center of the image display element, wherein a reflection surface closest to the second optical element on the optical path of the first optical element and an optical axis. , A straight line connecting the intersection of the reflection surface and the optical axis closest to the first optical element on the optical path of the second optical element, and the straight line connecting the intersection of the optical axis with the image display element on the optical path of the third optical element. When an angle between an intersection between the close reflection surface and the optical axis and a straight line connecting the intersection between the image display element and the optical axis is θ, 100 ° <θ <200 ° (1) The image display device according to claim 1, wherein the image display device is satisfied.