JP5108966B2 - Image display device - Google Patents

Description

  The present invention relates to an image display device, and in particular, a bright image of a display element of a type that displays an image by reflected light such as a reflective liquid crystal display element can be observed through an eyepiece optical system that is small and suppresses light loss as much as possible. The present invention relates to an image display device such as a head-mounted display devised.

  In recent years, with the development of head-up displays and eyeglass-type displays, development of compact eyepiece optical systems has progressed, and eyepieces using thin and compact decentered prisms described in Patent Document 1, Patent Document 2, Patent Document 3, and the like. Optical systems have been proposed. These are compact eyepieces that have power on the reflecting surface and the optical path is folded. The rotationally asymmetric decentering aberration that occurs due to the decentered reflecting surface that has power is reduced to the anamorphic reflecting surface or one symmetric surface. Correction is performed using a rotationally asymmetric reflecting surface having a surface.

  As for a liquid crystal display element for displaying an observation image, a reflective liquid crystal display element has been developed for forming a brighter and easier to observe image, and the one disclosed in Patent Document 4 is disclosed as including its illumination form. Has been.

  Further, as an eyepiece optical system using a reflective image display element brighter than a transmissive type such as a reflective liquid crystal display element, one disclosed in Patent Document 5 is known.

  However, the eyepiece optical system disclosed in Patent Document 5 is heavy because all optical members must be made of glass, and the configuration itself has a large number of parts. Further, since the illumination light to the reflective image display element is incident with a considerably large inclination from the vertical direction of the image plane, the brightness is sacrificed.

  Thus, it is conceivable to illuminate from a direction substantially perpendicular to the display surface of the reflective image display element. Conventionally, however, as described in Patent Documents 6 and 7, 45 in the observation optical path. A light splitting element such as a tilted half mirror or polarizing beam splitter was inserted, and illumination light was introduced from a direction orthogonal to the observation optical path. In addition, in order to make the light beam striking the display surface of the reflective image display device close to vertical, a light converging element that makes the illumination light beam diverging from the light source unit a substantially parallel light beam has been used.

  Although it is different from the image display device, as a light source device such as an endoscope, a microscope, and a projection exposure device, a reflection surface made of a rotationally asymmetric curved surface having power is used to converge a light beam from a light emitting unit. This is proposed in Patent Document 8.

JP-A-7-333551 JP-A-8-50256 JP-A-8-234137 Japanese Patent Laid-Open No. 10-268306 US Pat. No. 5,771,124 JP-A-7-128614 JP 2000-81591 A JP 11-237553 A

  However, in an image display device using a reflective image display element, if an illumination beam is introduced by inserting a light splitting element such as a half mirror or a polarizing beam splitter inclined at 45 ° in the observation optical path, the optical axis of the light splitting element The thickness in the direction is about the same as the width of the light beam there, and a space for the light converging element is also required, and the optical system cannot be miniaturized.

  The present invention has been made in view of such problems of the prior art, and its purpose is to form the shape of the half mirror surface of the light splitting element for illuminating the display surface of the reflective image display element substantially perpendicularly. It is possible to reduce the thickness of the light splitting element in the direction of the optical axis by devising a device, to eliminate the light converging element, and to make the light source close to the light splitting element. An object of the present invention is to provide an illuminable image display device.

The image display device of the first invention of the present invention that achieves the above object includes a reflective image display means for displaying an image by reflecting an illumination light beam incident from the front side of a display surface on which an image for observation is formed, and A light splitting element that causes illumination light to enter the display surface of the reflective image display means, and an eyepiece optical system that guides an image displayed on the display surface of the reflective image display means to a pupil position where the eyeball of the observer should be positioned In an image display device comprising:
The light splitting element includes a transflective surface that separates an observation optical path and an illumination optical path, and the transflective surface is formed in a rotationally asymmetric curved shape that gives positive power to an illumination light beam from an illumination light source. It is characterized by being.

An image display device according to a second aspect of the present invention includes a reflective image display means for displaying an image by reflecting an illumination light beam incident from the front side of a display surface on which an image for observation is formed, and the reflective image display An image comprising: a light splitting element that causes illumination light to enter the display surface of the means; and an eyepiece optical system that guides the image displayed on the display surface of the reflective image display means to a pupil position where the eyeball of the observer should be positioned In the display device,
An illumination light source is disposed at a position closer to the light splitting element than a position conjugate with the pupil position via the eyepiece optical system, the reflective image display means, and the light splitting element. is there.

An image display device according to a third aspect of the present invention includes a reflective image display means for displaying an image by reflecting an illumination light beam incident from the front side of a display surface on which an image for observation is formed, and the reflective image display An image comprising: a light splitting element that causes illumination light to enter the display surface of the means; and an eyepiece optical system that guides the image displayed on the display surface of the reflective image display means to a pupil position where the eyeball of the observer should be positioned In the display device,
The light splitting element is formed of a prism member, and the illumination light source surface is inclined with respect to the illumination light incident surface of the prism member.

  Hereinafter, the reason and effect | action which take said structure in this invention are demonstrated.

  First, a principal ray is defined. A ray that emerges from the center of the reflective image display element and reaches the center of the pupil of the observer's eyeball is defined as a principal ray. This principal ray is extended in the opposite direction from the reflective image display element, exits the light source, is reflected by the transflective surface of the light splitting element, is incident on the center of the reflective image display element, is reflected by the display surface, and then A ray that coincides with the principal ray is also a principal ray.

Now, with respect to the first aspect of the present invention, in order to give the light splitting element that makes the illumination light incident on the display surface of the reflective image display means the role of the light converging element, the inclination acts as a concave reflecting surface instead of a flat surface. Consider using a light splitting surface (semi-transmissive reflecting surface or half mirror surface). As described above, when the reflecting surface is inclined and concave, an asymmetrical aberration occurs. To correct this, the reflecting surface is a rotationally asymmetric aspherical surface. Considering the normal of the light splitting surface at the point where the chief ray is incident on the light splitting surface consisting of this concave reflecting surface, this rotationally asymmetric surface is constructed symmetrically with respect to the plane containing this normal and the chief ray. It is normal to do. In consideration of the manufacturability, a rotationally asymmetric surface having two symmetry surfaces may be used as the split reflection surface.

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

₆₆
Z = cr ² / [1 + √ {1− (1 + k) c ² r ² }] + ΣC _j X ^m Y ^{n
j = 2}
... (a)
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 vertex k: conic constant (conical constant)
r = √ (X ² + Y ² )
It is.

The free-form surface term is
₆₆
ΣC _j X ^m Y ^{n
j = 2}
= C ₂ X + C ₃ Y
+ C ₄ X ² + C ₅ XY + C ₆ Y ²
+ C ₇ X ³ + C ₈ X ² Y + C ₉ XY ² + C ₁₀ Y ³
+ C ₁₁ X ⁴ + C ₁₂ X ³ Y + C ₁₃ X ² Y ² + C ₁₄ XY ³ + C ₁₅ Y ⁴
+ C ₁₆ X ⁵ + C ₁₇ X ⁴ Y + C ₁₈ X ³ Y ² + C ₁₉ X ² Y ³ + C ₂₀ XY ⁴
+ C ₂₁ Y ⁵
+ C ₂₂ X ⁶ + C ₂₃ X ⁵ Y + C ₂₄ X ⁴ Y ² + C ₂₅ X ³ Y ³ + C ₂₆ X ² Y ⁴
+ C ₂₇ XY ⁵ + C ₂₈ Y ⁶
+ C ₂₉ X ⁷ + C ₃₀ X ⁶ Y + C ₃₁ X ⁵ Y ² + C ₃₂ X ⁴ Y ³ + C ₃₃ X ³ Y ⁴
+ C ₃₄ X ² Y ⁵ + C ₃₅ XY ⁶ + C ₃₆ Y ⁷
・ ・ ・ ・ ・ ・
However, C _j (j is an integer of 2 or more) is a coefficient.

In general, the free-form surface does not have a symmetric surface in both the XZ plane and the YZ plane. However, in the present invention, by setting all odd-order terms of X to 0, the free-form surface is parallel to the YZ plane. This is a free-form surface with only one symmetrical plane. For example, in the above defining equation _{(a), C 2, C} 5, C 7, C 9, C 12, C 14, C 16, C 18, C 20, C 23, C 25, C 27, C 29, This is possible by setting the coefficient of each term of C ₃₁ , C ₃₃ , C ₃₅ .

Further, by setting all odd-numbered 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 , This is possible by setting the coefficient of each term of C ₃₄ , C ₃₆ .

  Further, any one of the directions of the symmetry plane is set 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, XZ By making the decentering direction of the optical system parallel to the plane parallel to the X-axis direction, it is possible to improve the manufacturability at the same time while effectively correcting the rotationally asymmetric aberration caused by the decentering. Become.

  The definition formula (a) is shown as an example as described above. In the present invention, the rotation generated by eccentricity by using a rotationally asymmetric surface having only one or two symmetry surfaces. It is characterized by correcting asymmetrical aberrations and improving the manufacturability at the same time, and it goes without saying that the same effect can be obtained for any other defining formula.

Now, consider the power (reflection power) of the rotationally asymmetric split reflection surface. The direction in the plane of symmetry is the Y direction, and the direction in the plane perpendicular to the Y direction is the X direction. Although the power differs in the Y direction and the X direction, they are assumed to be φ _y and φ _x , respectively. In addition, the size (screen size) of the reflective image display element is W _y and W _x with respect to the Y direction and the X direction.

First,
0.05 <φ _y × W _y <3 (1)
It is desirable that the surface satisfies the above conditions. Here, φ _y × W _y is a parameter corresponding to the numerical aperture in the Y direction, and when φ _y × W _y becomes the lower limit value 0.05 or less, the power of the divided reflection surface becomes too weak and the light source must be enlarged. It becomes impossible to illuminate and the optical system cannot be made small. On the other hand, if φ _y × W _y exceeds the upper limit of 3 or more, the power is too strong, the light source position becomes too close to the split reflecting surface and interferes with the observation optical path, and the aberration of the illumination optical system increases. Thus, the reflective image display element cannot be effectively illuminated.

This conditional expression (1) is
0.2 <φ _y × W _y <1.0 (1-1)
If this condition is satisfied, it will be more advantageous for miniaturization,
0.25 <φ _y × W _y <0.8 (1-2)
This is more desirable.

By the way, the relationship between φ _y × W _y and φ _x × W _x is
φ _y × W _y <φ _x × W _x (2)
It is desirable to satisfy the following conditions. If the condition (2) is not satisfied, the power balance is lost in the direction in which the illumination light is bent (Y direction) and the direction in which the illumination light is not bent (X direction), and uniform illumination becomes difficult.

In the examples below,
W _x W _y φ _x φ _y φ _x × W _x φ _y × W _y
Example 1 11.5 7.2 0.14 0.092 1.58 0.67
Example 2 7.2 7.2 0.058 0.039 0.41 0.28
Example 3 11.52 7.2 0.16 0.10 1.84 0.72
Example 4 11.52 7.2 0.16 0.10 1.84 0.72
It is.

  In addition, it is desirable that the split reflection surface is composed of a prism member provided on the bonding surface of two transparent members.

Next, the second invention of the present invention will be described. In the case of an arrangement in which illumination light is incident on the display surface of an image display means such as a reflective liquid crystal display element via a light splitting element, the illumination light source is usually a position conjugate with the pupil position where the observer's eyeball should be located. However, in order to make the optical system more compact, in the present invention, the optical system is arranged at a position closer to the light splitting element than its conjugate position.

  FIG. 1 is a cross-sectional view including the principal ray (optical axis) of the optical system of the image display apparatus of Example 1 described later, and the second invention will be described based on this. The optical system includes an exit pupil 1, an eyepiece optical system 3 including three decentered prisms 10, 20, and 30, a light splitting element 4 having a light splitting surface 40 that is a semi-transmissive reflection surface, A light source surface 6 is disposed on the reflection side (illumination light incident side) of the light splitting surface 40 of the light splitting device 4 and is a surface conjugate with the exit pupil 1. 7 is located.

The point where the optical axis (principal ray) 2 intersects the light splitting surface 40 is N, the point where the optical axis (chief ray) 2 intersects the surface 7 conjugate to the exit pupil 1 is P, the point where it intersects the light source surface 6 is L, and the optical path length NL is the optical path length. When the value divided by NP is α,
0.5 <α <0.9 (3)
It is desirable to arrange the light source surface 6 so as to satisfy the above.

  If α exceeds the lower limit value 0.5 of the condition (3), the light source position is too close to the observation optical path and interferes with the observation optical path. If α exceeds the upper limit of 0.9, the position of the light source is too far from the optical system of the image display device, and the optical system cannot be miniaturized.

This condition is
0.7 <α <0.8 (3-1)
It is still desirable.

In the examples below,
NP NL α
Example 1 15.18 11.82 0.78
Example 2 17.58 13.37 0.76
Example 3 13.19 11.41 0.87
Example 4 13.19 11.41 0.87
It is.

  Next, the third invention of the present invention will be described. In the case of an arrangement in which illumination light is incident on a display surface of an image display means such as a reflective liquid crystal display element via a light splitting element made of a prism member, the back ray tracing is performed from the observer's eyeball side (exit pupil), Consider a light beam reflected by a reflective image display element. For example, in FIG. 1, a light beam reflected by a concave light splitting surface 40 made of a free-form surface of a light splitting element 4 made of a prism member converges on a plane (incidence pupil) 7 conjugate to the exit pupil 1. Sometimes asymmetric aberrations occur. This is corrected by the rotationally asymmetric surface of the light splitting surface 40, but part of the aberration can be corrected by tilting the incident surface 43 of the prism member of the light splitting element 4 with respect to the optical axis 2. If the light source surface 6 is arranged in parallel to the inclined prism incident surface 43, the distribution of illumination light on the image display surface 5 becomes non-uniform. Therefore, in the third aspect of the invention, the light source surface 6 is slightly inclined with respect to the prism incident surface 43 so as to obtain light distribution uniformity.

The angle formed between the prism incident surface 43 and the light source surface 6 is β, and the distance between the prism incident surface 43 and the light source surface 6 is closer to the image display surface 5 of the prism incident surface 43 as shown in FIG. If β is defined as positive when
2 ° <β <30 ° (4)
It is desirable to satisfy.

As described above, when the angle of the prism incident surface 43 is determined so that the pupil aberration at the entrance pupil 7 is reduced, if β exceeds 2 ° which is the lower limit of the condition (4), the reflective image display surface 5 If the amount of illumination light is insufficient on the side close to the light source 6 and β exceeds the upper limit of 30 °, the amount of illumination light is insufficient on the side far from the light source 6 of the reflective image display surface 5.

This condition is
4 ° <β <18 ° (4-1)
It is still desirable.

In the examples below,
β
Example 1 15 °
Example 2 5 °
Example 3 20 °
Example 4 15 °
It is.

Conventionally, the chief ray 2 of the illumination light exiting from the center of the light source surface 6 is deflected at right angles by the light splitting element 4. In order to reduce the size of the optical system of the image display device, it is desirable to make the deflection angle larger than 90 ° so that the light source surface 6 is closer to the display surface 5 side. When this deflection angle is θ,
94 ° <θ <120 ° (5)
Those satisfying these conditions are advantageous for downsizing.

  If θ is less than 94 °, which is the lower limit of condition (5), there is almost no effect on downsizing. When θ exceeds the upper limit of 120 °, the light beam reflected by the portion near the image display surface 5 of the light dividing surface 40 interferes with the reflective image display element between the light source 6 and the light dividing surface 40. The light splitting element 4 cannot be downsized.

  It is even better if θ satisfies the following conditions.

100 ° <θ <115 ° (5-1)
More preferably, θ satisfies the following condition.

105 ° <θ <110 ° (5-1)
In the examples below,
θ
Example 1 108.2 °
Example 2 106.0 °
Example 3 108.2 °
Example 4 108.2 °
It is.

  In the image display device using the reflective image display element of the present invention, if there is a surface having a high reflectance between the light splitting element 4 and the image display surface 5, it becomes unnecessary light for the image. In order to reduce this, the light splitting element 4 and the cover glass 51 of the reflective image display element are joined using an optical adhesive having a refractive index matching function, and the reflectance is lowered by eliminating the air contact surface. , Unnecessary light can be reduced.

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

  In addition, the image display apparatus includes a pair of the above optical systems for the right eye and the left eye.

  In addition, the image display device includes an image display device configured to include a support unit that supports the viewer's head so that the image display device is positioned in front of the viewer's face.

  As is apparent from the above description, according to the present invention, in an image display apparatus using a reflective image display element, power is applied to the light dividing surface of the light dividing element that makes illumination light incident on the display surface of the reflective image display means. By reducing the thickness of the light splitting element in the optical axis direction, the light converging element can be omitted, uniform illumination is possible, and a compact image display device can be configured with a small number of parts. In addition, the aberration is determined only by the accuracy of the parts, and the accuracy when the image display apparatus is assembled becomes loose.

It is sectional drawing of the optical system of the image display apparatus of Example 1 of this invention. It is sectional drawing of the optical system of the image display apparatus of Example 2 of this invention. It is sectional drawing of the optical system of the image display apparatus of Example 3 of this invention. It is sectional drawing of the optical system of the image display apparatus of Example 4 of this invention. It is a figure which shows an example of the eccentric prism applicable to the prism of the eyepiece optical system of the image display apparatus of this invention. It is a figure which shows another example of the eccentric prism applicable to the prism of the eyepiece optical system of the image display apparatus of this invention. It is a figure which shows another example of the eccentric prism applicable to the prism of the eyepiece optical system of the image display apparatus of this invention. It is a figure which shows another example of the eccentric prism applicable to the prism of the eyepiece optical system of the image display apparatus of this invention. It is a figure which shows another example of the eccentric prism applicable to the prism of the eyepiece optical system of the image display apparatus of this invention. It is a figure which shows another example of the eccentric prism applicable to the prism of the eyepiece optical system of the image display apparatus of this invention. It is a figure which shows another example of the eccentric prism applicable to the prism of the eyepiece optical system of the image display apparatus of this invention. It is a figure which shows another example of the eccentric prism applicable to the prism of the eyepiece optical system of the image display apparatus of this invention. It is a figure which shows the state which mounted | wore the observer head with the image display apparatus for binocular mounting | wearing type | mold by this invention. It is sectional drawing of FIG. It is a figure which shows the state which mounted | wore the observer's head with the image display apparatus for single-eye mounting | wearing type by this invention.

  Examples 1 to 4 of the optical system of the image display device of the present invention will be described below. Although this embodiment will be described by back ray tracing, it can be used as an image display device by disposing a reflective image display element on the image plane and disposing the pupil of the observer's eyeball at the pupil position. The configuration parameters of this embodiment will be shown later.

In each embodiment, as shown in FIG. 1, the axial principal ray 2 leaves 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, and the light source surface. It is defined by the ray reaching the center of 6. The position along the axial principal ray 2 incident on the surface of the pupil 1 is defined as the Z axis, with the position where the axial principal ray 2 is incident on the pupil 1 surface being the origin of the optical surface constituting the optical system of the image display apparatus. A plane including the Z axis and the center of the image plane is defined as a YZ plane, a direction passing through the origin and orthogonal to the YZ plane, and a direction from the front side of the paper toward the back side is defined as the X axis positive direction. The axis constituting the Z-axis and the right-handed orthogonal coordinate system is taken as the Y-axis. FIG. 1 shows a coordinate system defined for the origin.

  In the first to fourth embodiments, the surface is decentered in the YZ plane of the coordinate system defined with respect to the center of the pupil 1, and the only symmetric surface of each rotationally asymmetric free-form surface is the YZ plane. It is said. For each eccentric surface, from the origin of the coordinate system determined for the center of the pupil 1, the amount of eccentricity of the surface top position of the surface (X-axis direction, Y-axis direction, Z-axis direction is X, Y, Z, respectively) and The X axis, Y axis, and Z axis of the center axis of the surface (Z axis in the above equation (a) for a free-form surface and the Z axis in equation (b) below for an aspherical surface) are the centers. Tilt angles (α, β, γ (°), respectively) are given. In this case, positive α and β mean counterclockwise rotation with respect to the positive direction of each axis, and positive γ means clockwise rotation with respect to the positive direction of the Z axis.

  Further, among the optical action surfaces constituting the optical system of the embodiment, when a specific surface and a subsequent surface constitute a coaxial optical system, a surface interval is given, and in addition, the refractive index of the medium, Abbe numbers are given according to idioms.

  Further, the shape of the surface of the free curved surface used in the present invention is defined by the equation (a), and the Z axis of the defining equation becomes the axis of the free curved surface.

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

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

  Note that terms relating to free-form surfaces and aspheric surfaces for which no data is described are zero. The refractive index is shown for d-line (wavelength 587.56 nm). The unit of length is mm.

  As another defining formula of the free-form surface, there is a Zernike polynomial given by the following equation (c). The shape of this surface is defined by the following equation. The Z axis of the defining formula becomes 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 is expressed by the rotation angle measured from.

x = R × cos (A)
y = R × sin (A)
Z = D ₂
+ D ₃ Rcos (A) + D ₄ Rsin (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 order to design an optical system symmetrical in the X-axis direction, D ₄ , D ₅ , D ₆ , D ₁₀₀ , D ₁₁ , D ₁₂ , D ₁₃ , D ₁₄ , D ₂₀ , D ₂₁ , D ₂₂ . Is used.

  The following definition formula (d) can be given as an example of other aspects.

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

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 expressed by a free-form surface using the above equation (a), but the same effect can be obtained by using the above equations (c) and (d). Needless to say.

  A YZ sectional view including the optical axis 2 of Example 1 of the present invention is shown in FIG. The half angle of view of the observation optical system of this example is 18 ° in the X direction and 11.5 ° in the Y direction, and the size of the reflective image display element is 11.5 × 7.2 mm.

  In this embodiment, the light splitting element includes an exit pupil 1, an eyepiece optical system 3 including decentering prisms 10, 20, and 30, and a light splitting surface 40 of a transflective surface in the order in which light passes from the object side. 4 is composed of a display surface 5 of a reflective image display element, and a light source surface 6 is disposed on the reflection side (illumination light incident side) of the light splitting surface 40 of the light splitting element 4 and is conjugate to the exit pupil 1. A flat surface 7 is located.

  The decentered prism 10 of the eyepiece optical system 3 includes 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 be reflected by the second surface 12. The second surface 12 reflects the light beam incident from the first surface 11 in the prism, and the third surface 13 emits the light beam reflected by the first surface 11 to the outside of the prism. The first surface 11 is the same optical action surface having both transmission and reflection effects.

  The decentered prism 20 of the eyepiece optical system 3 is composed of a first surface 21 to a third surface 23. The first surface 21 causes the light beam from the decentered prism 10 to enter the prism 20, and the second surface 22 is the first surface. The light beam incident from 21 is reflected inside 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 decentered prism 30 of the eyepiece optical system 3 includes a first surface 31 to a fourth surface 34. The first surface 31 causes the light beam from the decentered prism 20 to enter the prism 30, and the second surface 32 is the first surface. The light beam incident from 31 is reflected in the prism, and the third surface 33 reflects the light beam reflected by the second surface 32 in the prism so as to intersect the light beam incident on the second surface 32 from the first surface 31. The fourth surface 34 is configured to emit the light beam reflected by the third surface 33 to the outside of the prism.

  The eyepiece optical system 3 including the three decentered prisms 10 to 30 is an optical system that forms an intermediate image once.

  The light splitting element 4 is composed of a cemented prism member in which two transparent media 41 and 42 are joined, and has a light splitting surface 40 which is a semi-transmissive reflection surface on the joint surface. Through the cover glass 51 of the reflective image display element that passes through the dividing surface 40 and the image display element facing surface 45 and is bonded to the image display element facing surface 45, the display surface 5 of the reflective image display element is reached. The light beam reflected by the display surface 5 passes through the cover glass 51 and the image display element facing surface 45, is reflected by the light splitting surface 40, and exits from the illumination light incident surface 43 of the light splitting device 4 to the outside of the prism. To face 6. The image of the exit pupil 1 is formed on a plane 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 plane 7 conjugate with the exit pupil 1 is joined from the illumination light incident surface 43 of the light splitting element 4. The light enters the prism member, is reflected by the light splitting surface 40, becomes a substantially parallel light beam, exits from the image display element facing surface 45 to the outside of the cemented prism member, and passes through the cover glass 51 to display the display surface 5 of the reflective image display element. Illuminate approximately vertically. Display light from the display surface 5 of the reflective liquid crystal display element enters the joining prism member through the cover glass 51 from the image display element facing surface 45 of the light splitting element 4, and this time passes through the light splitting surface 40. 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 internally reflected by the second surface 32. Reflected, emitted from the first surface 31 to the outside of the prism 30, entered from the third surface 23 of the decentered prism 20 into the prism 20, internally reflected by the second surface 22, and emitted from the first surface 21 to the outside of the prism 20. Then, the light 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, is refracted by the first surface 11, and exits the prism 10. Enters the observer's eyeball at the position of exit pupil 1 To form an enlarged image of the displayed image of the reflection type liquid crystal display device.

  The second to fifth surfaces of the constituent parameters described later are prisms 10, the sixth to eighth surfaces are prisms 20, the ninth to twelfth surfaces are prisms 30, and the thirteenth surface. From the 14th surface to the 14th surface is the light splitting element 4 at the time of image display, the 14th surface to the 15th surface is the cover glass 51, the 15th surface is the display surface 5, and the 15th surface to the 16th surface. Is the cover glass 51, the seventeenth surface is the light dividing surface 40 as a reflecting surface, the eighteenth surface is the illumination light incident surface 43 of the light dividing element 4, the nineteenth surface is the light source surface 6, and the image The surface (20th surface) is a surface 7 conjugate with the exit pupil 1. Each surface from the second surface to the image surface (the twentieth surface) is represented by an amount of eccentricity with reference to the center of the exit pupil 1 of the first surface.

  A YZ sectional view including the optical axis 2 of Example 2 of the present invention is shown in FIG. The observation optical system of this example has a half field angle of 8.3 ° in the X direction and 8.3 ° in the Y direction, and the size of the reflective image display element is 7.2 × 7.2 mm.

  In this embodiment, in reverse ray tracing, in order of light passing from the object side, an eyepiece optical system 3 including an exit pupil 1, a decentered prism 10, a light splitting element 4 having a light splitting surface 40 of a semi-transmissive reflection surface, a reflective type A light source surface 6 is arranged on the reflection side (illumination light incident side) of the light splitting surface 40 of the light splitting element 4, and a surface 7 conjugate with the exit pupil 1 is formed of the display surface 5 of the image display element. To position.

  The decentered prism 10 of the eyepiece optical system 3 includes 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 be reflected by the second surface 12. The second surface 12 reflects the light beam incident from the first surface 11 in the prism, and the third surface 13 emits the light beam reflected by the first surface 11 to the outside of the prism. The first surface 11 is the same optical action surface having both transmission and reflection effects.

  The eyepiece optical system 3 including only the decentering prism 10 is an optical system that does not form an intermediate image.

  The light splitting element 4 is composed of a cemented prism member in which two transparent media 41 and 42 are joined, and has a light splitting surface 40 which is a semi-transmissive reflection surface on the joint surface. Through the cover glass 51 of the reflective image display element that passes through the dividing surface 40 and the image display element facing surface 45 and is bonded to the image display element facing surface 45, the display surface 5 of the reflective image display element is reached. The light beam reflected by the display surface 5 passes through the cover glass 51 and the image display element facing surface 45, is reflected by the light splitting surface 40, and exits from the illumination light incident surface 43 of the light splitting device 4 to the outside of the prism. To face 6. The image of the exit pupil 1 is formed on a plane 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 plane 7 conjugate with the exit pupil 1 is joined from the illumination light incident surface 43 of the light splitting element 4. The light enters the prism member, is reflected by the light splitting surface 40, becomes a substantially parallel light beam, exits from the image display element facing surface 45 to the outside of the cemented prism member, and passes through the cover glass 51 to display the display surface 5 of the reflective image display element. Illuminate approximately vertically. Display light from the display surface 5 of the reflective liquid crystal display element enters the joining prism member through the cover glass 51 from the image display element facing surface 45 of the light splitting element 4, and this time passes through the light splitting surface 40. Then, the light exits from the cemented prism member through its exit surface 44, enters the prism 10 from the third surface 13 of the decentered prism 10 of the eyepiece optical system 3, is totally reflected by the first surface 11, and is reflected by the second surface 12. This time, the light is refracted by the first surface 11 and exits from the prism 10, enters the observer's eyeball at the position of the exit pupil 1, and forms an enlarged image of the display image of the reflective liquid crystal display element.

  The second to fifth structural parameters described later are prisms 10, the sixth to seventh surfaces are the light splitting elements 4 during image display, and the seventh to eighth surfaces are cover glasses. 51, the eighth surface is the display surface 5, the eighth surface to the ninth surface is the cover glass 51, the tenth surface is the light splitting surface 40 as a reflecting surface, and the eleventh surface is the light splitting. The illumination light incident surface 43 of the element 4, the twelfth surface is the light source surface 6, and the image surface (13th surface) is a surface 7 conjugate with the exit pupil 1. Each surface from the second surface to the image surface (the thirteenth surface) is represented by an amount of eccentricity with reference to the center of the exit pupil 1 of the first surface.

  FIG. 3 shows a YZ sectional view including the optical axis 2 of Example 3 of the present invention. The observation optical system of this example has a half field angle of 16 ° in the X direction and 10.2 ° in the Y direction, and the size of the reflective image display element is 11.52 × 7.2 mm.

In this embodiment, the light splitting element includes an exit pupil 1, an eyepiece optical system 3 including decentering prisms 10, 20, and 30, and a light splitting surface 40 of a transflective surface in the order in which light passes from the object side. 4, a wobbling element 8 and a display surface 5 of a reflective image display element. A light source surface 6 is disposed on the reflection side (illumination light incident side) of the light splitting surface 40 of the light splitting element 4. A plane 7 conjugate to the pupil 1 is located.

  Here, the wobbling element 8 is formed by sequentially arranging a phase modulation element and a birefringent medium as disclosed in Japanese Patent Laid-Open No. 7-36054, and the display surface 5 of the image display element is set in a one-dimensional direction or 2 It is an element that achieves high resolution by wobbling in the dimensional direction (pixel shift, pixel shift), and is represented by a parallel plate in the constituent parameters described later. 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 formed of a cemented prism member in which two transparent media 41 and 42 are joined. The light splitting element 4 includes a light splitting surface 40 that is a semi-transmissive reflection surface on the joint surface. The wobbling element 8 that is transmitted through the light dividing surface 40 and the image display element facing surface 45 and is bonded to the image display element facing surface 45 and the cover of the reflective image display element that is bonded to the opposite side of the wobbling element 8 The light beam that has passed through the glass 51 reaches the display surface 5 of the reflective image display element and is reflected by the display surface 5 passes through the cover glass 51, the wobbling element 8, and the image display element facing surface 45, thereby splitting the light. The light is reflected by 40, emitted from the illumination light incident surface 43 of the light splitting element 4 to the outside of the prism, and reaches the light source surface 6. The image of the exit pupil 1 is formed on a plane 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 plane 7 conjugate with the exit pupil 1 is joined from the illumination light incident surface 43 of the light splitting element 4. The light enters the prism member, is reflected by the light splitting surface 40, becomes a substantially parallel light beam, exits from the image display element facing surface 45 to the outside of the cemented prism member, and is reflected through the wobbling element 8 and the cover glass 51. The display surface 5 is illuminated substantially vertically. The display light from the display surface 5 of the reflective 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 face 40 passes 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 secondly reflected. Reflected internally by the surface 32, exited from the first surface 31 to the prism 30, entered the prism 20 from the third surface 23 of the decentered prism 20, reflected internally by the second surface 22, and reflected from the first surface 21 to the prism 20, 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 is refracted by the first surface 11 and is refracted by the first surface 11. To the position of exit pupil 1 It enters that observer eyeball to form an enlarged image of the displayed image of the reflection type liquid crystal display device.

  The second to fifth surfaces of the constituent parameters described later are prisms 10, the sixth to eighth surfaces are prisms 20, the ninth to twelfth surfaces are prisms 30, and the thirteenth surface. From the 14th surface to the 14th surface is the light splitting element 4 at the time of image display, the 14th surface to the 15th surface is the wobbling element 8, the 15th surface to the 16th surface is the cover glass 51, and the 16th surface Is the display surface 5, the cover glass 51 is from the 16th surface to the 17th surface, the wobbling element 8 is from the 17th surface to the 18th surface, and the light splitting surface 40 as the reflection surface is the 19th surface. The 20th surface is the illumination light incident surface 43 of the light splitting element 4, the 21st surface is the light source surface 6, and the image surface (22nd surface) is the surface 7 conjugate with the exit pupil 1. Each surface from the second surface to the image surface (the 22nd surface) is represented by an eccentric amount with the center of the exit pupil 1 of the first surface as a reference.

  FIG. 4 shows a YZ sectional view including the optical axis 2 of Example 4 of the present invention. The observation optical system of this example has a half field angle of 18 ° in the X direction and 11.5 ° in the Y direction, and the size of the reflective image display element is 11.52 × 7.2 mm.

In this embodiment, in reverse ray tracing, the eyepiece optical system 3 including the exit pupil 1, the decentering prisms 10, 20, and 30, the wobbling element 8, and the light dividing surface 40 of the transflective surface are arranged in the order in which light passes from the object side.
And a light source surface 6 is disposed on the reflection side (illumination light incident side) of the light splitting surface 40 of the light splitting device 4. A plane 7 conjugate to the exit pupil 1 is located.

  In this embodiment, 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 splitting element 4 is composed of a cemented prism member in which two transparent media 41 and 42 are joined. The light splitting element 4 includes a light splitting surface 40 which is a semi-transmissive reflection surface on the joint surface. The wobbling element 8 is bonded to the surface 44. In the reverse ray tracing, the wobbling element 8, the exit surface 44, the light splitting surface 40, and the image display element facing surface 45 are transmitted and are bonded to the image display element facing surface 45. The light beam reflected by the display surface 5 passes through the cover glass 51 and the image display element facing surface 45 through the cover glass 51 of the reflective image display element. The light is reflected by the light splitting surface 40, exits from the illumination light incident surface 43 of the light splitting element 4, and reaches the light source surface 6. The image of the exit pupil 1 is formed on a plane 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 plane 7 conjugate with the exit pupil 1 is joined from the illumination light incident surface 43 of the light splitting element 4. The light enters the prism member, is reflected by the light splitting surface 40, becomes a substantially parallel light beam, exits from the image display element facing surface 45 to the outside of the cemented prism member, and passes through the cover glass 51 to display the display surface 5 of the reflective image display element. Illuminate approximately vertically. Display light from the display surface 5 of the reflective liquid crystal display element enters the joining prism member through the cover glass 51 from the image display element facing surface 45 of the light splitting element 4, and this time passes through the light splitting surface 40. From the exit surface 44 to the outside of the cemented prism member, through the wobbling element 8, through the fourth surface 34 of the decentered prism 30 of the eyepiece optical system 3, into the prism 30, and internally reflected by the third surface 33, Internally reflected by the second surface 32, emitted from the first surface 31 to the outside of the prism 30, entered from the third surface 23 of the decentered prism 20 into the prism 20, internally reflected by the second surface 22, and first surface 21. From the third surface 13 of the prism 10 into the prism 10, totally reflected by the first surface 11, reflected by the second surface 12, and then refracted by the first surface 11. 10 out of the exit pupil 1 It enters the observer's eyeball in the location, to form an enlarged image of the displayed image of the reflection type liquid crystal display device.

  The second to fifth surfaces of the constituent parameters described later are prisms 10, the sixth to eighth surfaces are prisms 20, the ninth to twelfth surfaces are prisms 30, and the thirteenth surface. From the 14th surface to the 14th surface is the wobbling element 8, the 14th surface to the 15th surface is the light splitting element 4 at the time of image display, the 15th surface to the 16th surface is the cover glass 51, the 16th surface Is the display surface 5, the 16th surface to the 17th surface is the cover glass 51, the 18th surface is the light dividing surface 40 as a reflecting surface, and the 19th surface is the illumination light incident surface of the light dividing element 4. 43, the 20th surface is the light source surface 6, and the image surface (21st surface) is the surface 7 conjugate with the exit pupil 1. Each surface from the second surface to the image surface (the 21st surface) is represented by an amount of eccentricity with reference to the center of the exit pupil 1 of the first surface.

The configuration parameters of Examples 1 to 4 are shown below. In the table below, “FFS” indicates a free-form surface, and “ASS” indicates an aspheric surface.
Example 1
Surface number Curvature radius Surface spacing Eccentric Refractive index Abbe number Object surface ∞ -1250.00
1 ∞ (Eye) Eccentricity (1)
2 ASS [1] Eccentricity (2) 1.4924 57.6
3 FFS [1] Eccentricity (3) 1.4924 57.6
4 ASS [1] Eccentricity (2) 1.4924 57.6
5 FFS [2] Eccentricity (4)
6 ASS [2] Eccentricity (5) 1.4924 57.6
7 ∞ Eccentricity (6) 1.4924 57.6
8 ASS [3] Eccentricity (7)
9 FFS [3] Eccentricity (8) 1.4924 57.6
10 FFS [4] Eccentricity (9) 1.4924 57.6
11 FFS [5] Eccentricity (10) 1.4924 57.6
12 FFS [6] 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 [7] Eccentricity (15) 1.4924 57.6
18 ∞ Eccentricity (16)
19 ∞ Eccentricity (17)
Image plane ∞ Eccentricity (18)
ASS [1]
R -55.44
K 2.1396 × 10 ^-1
A 3.9915 × 10 ^-6
B 2.2958 × 10 ^-9
C -3.1207 × 10 ^-12
ASS [2]
R 18.43
K 7.4067 × 10 ^-1
A 5.3964 × 10 ^-5
B 1.0832 × 10 ^-6
C -9.4725 × 10 ^-9
ASS [3]
R 17.33
K -1.7782
A -5.5187 × 10 ^-5
B -1.2987 × 10 ^-7
C -7.8713 × 10 ^-9
FFS [1]
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 [2]
C ₄ 2.2988 × 10 ^-2 C ₆ 8.7785 × 10 ^-3 C ₈ 5.5743 × 10 ^-4
C ₁₀ 4.1097 × 10 ^-4 C ₁₁ 2.4 130 × 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 [3]
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 [4]
C ₄ 3.9701 × 10 ^-3 C ₆ 2.9194 × 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 [5]
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 [6]
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 2.9510 × 10 ^-5
C ₂₁ 2.5078 × 10 ^-6
FFS [7]
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
Eccentricity (8)
X 0.00 Y 22.40 Z 45.39
α 174.59 β 0.00 γ 0.00
Eccentric (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
Eccentric (11)
X 0.00 Y 18.76 Z 51.08
α 89.86 β 0.00 γ 0.00
Eccentric (12)
X 0.00 Y 17.76 Z 50.70
α 89.58 β 0.00 γ 0.00
Eccentric (13)
X 0.00 Y 7.76 Z 50.62
α 89.58 β 0.00 γ 0.00
Eccentric (14)
X 0.00 Y 4.48 Z 50.60
α 89.58 β 0.00 γ 0.00
Eccentric (15)
X 0.00 Y 13.86 Z 50.67
α 125.47 β 0.00 γ 0.00
Eccentric (16)
X 0.00 Y 11.73 Z 56.98
α 169.38 β 0.00 γ 0.00
Eccentric (17)
X 0.00 Y 11.04 Z 58.73
α 154.38 β 0.00 γ 0.00
Eccentric (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 spacing Eccentricity Refractive index Abbe number Object surface ∞ -1000.00
1 ∞ (Eye) Eccentricity (1)
2 ASS [1] Eccentricity (2) 1.5254 56.2
3 FFS [1] Eccentricity (3) 1.5254 56.2
4 ASS [1] Eccentricity (2) 1.5254 56.2
5 FFS [2] Eccentricity (4)
6 ∞ Eccentricity (5) 1.5254 56.2
7 ∞ Eccentricity (6) 1.5 230 59.4
8 ∞ Eccentricity (7) 1.5 230 59.4
9 ∞ Eccentricity (6) 1.5254 56.2
10 FFS [3] Eccentricity (8) 1.5254 56.2
11 ∞ Eccentricity (9)
12 ∞ Eccentricity (10)
Image plane ∞ Eccentricity (11)
ASS [1]
R -175.89
K -4.2384 × 10 ¹
A -1.3242 × 10 ^-6
B 2.3803 × 10 ^-9
C -1.4058 × 10 ^-12
FFS [1]
C ₄ -7.0 300 × 10 ^-3 C ₆ -6.2313 × 10 ^-3 C ₈ 5.4996 × 10 ^-5
C ₁₀ 8.2785 × 10 ^-5 C ₁₁ 9.6861 × 10 ^-7 C ₁₃ 2.6608 × 10 ^-6
C ₁₅ 2.2262 × 10 ^-6 C ₁₇ -7.0463 × 10 ^-9 C ₁₉ 8.5 166 × 10 ^-8
C ₂₁ 2.5498 × 10 ^-8
FFS [2]
C ₄ -2.4081 × 10 ^-2 C ₆ -3.2942 × 10 ^-2 C ₈ 1.9668 × 10 ^-4
C ₁₀ 4.4387 × 10 ^-4 C ₁₁ 1.5508 × 10 ^-5 C ₁₃ 8.3803 × 10 ^-5
C ₁₅ 3.0133 × 10 ^-5 C ₁₇ -7.4980 × 10 ^-7 C ₁₉ -4.5423 × 10 ^-6
C ₂₁ -1.6514 × 10 ^-6
FFS [3]
C ₄ 8.3631 × 10 ^-3 C ₆ 4.2922 × 10 ^-3 C ₈ 7.0509 × 10 ^-4
C ₁₀ 2.9488 × 10 ^-4 C ₁₁ 5.6313 × 10 ^-5 C ₁₃ 2.5429 × 10 ^-5
C ₁₅ 6.0775 × 10 ^-5 C ₁₇ -2.1308 × 10 ^-5 C ₁₉ -3.0197 × 10 ^-6
C ₂₁ -7.2724 × 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 -2.98 Z 32.35
α 5.66 β 0.00 γ 0.00
Eccentricity (3)
X 0.00 Y 3.25 Z 42.53
α -14.81 β 0.00 γ 0.00
Eccentricity (4)
X 0.00 Y 17.32 Z 39.86
α 57.58 β 0.00 γ 0.00
Eccentricity (5)
X 0.00 Y 20.22 Z 39.33
α 49.52 β 0.00 γ 0.00
Eccentricity (6)
X 0.00 Y 27.82 Z 45.82
α 49.52 β 0.00 γ 0.00
Eccentricity (7)
X 0.00 Y 28.66 Z 46.53
α 49.52 β 0.00 γ 0.00
Eccentricity (8)
X 0.00 Y 23.34 Z 43.69
α 87.52 β 0.00 γ 0.00
Eccentric (9)
X 0.00 Y 30.30 Z 37.51
α 125.32 β 0.00 γ 0.00
Eccentricity (10)
X 0.00 Y 30.92 Z 37.00
α 120.32 β 0.00 γ 0.00
Eccentric (11)
X 0.00 Y 34.38 Z 34.62
α 125.32 β 0.00 γ 0.00.

(Example 3)
Surface number Curvature radius Surface spacing Eccentric Refractive index Abbe number Object surface
∞ -1000.00
1 ∞ (Eye) Eccentricity (1)
2 ASS [1] Eccentricity (2) 1.4924 57.6
3 FFS [1] Eccentricity (3) 1.4924 57.6
4 ASS [1] Eccentricity (2) 1.4924 57.6
5 FFS [2] 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 [3] Eccentricity (8) 1.4924 57.6
10 FFS [4] Eccentricity (9) 1.4924 57.6
11 FFS [5] Eccentricity (10) 1.4924 57.6
12 FFS [6] 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 [7] Eccentricity (16) 1.4924 57.6
20 ∞ Eccentricity (17)
21 ∞ Eccentricity (18)
Image plane ∞ Eccentricity (19)
ASS [1]
R -51.67
K 2.4332
A -8.3613 × 10 ^-7
B 2.3570 × 10 ^-8
C -1.8757 × 10 ^-11
FFS [1]
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 [2]
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 [3]
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 [4]
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 [5]
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 -4.3121 × 10 ^-7 C ₁₉ -1.2927 × 10 ^-6
C ₂₁ -9.1384 × 10 ^-7
FFS [6]
C ₄ -4.0255 × 10 ^-3 C ₆ 2.1274 × 10 ^-2 C ₈ -2.6302 × 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 [7]
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 2.1203 × 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
Eccentric (9)
X 0.00 Y 24.45 Z 57.19
α 151.80 β 0.00 γ 0.00
Eccentric (10)
X 0.00 Y 30.18 Z 52.34
α 104.83 β 0.00 γ 0.00
Eccentric (11)
X 0.00 Y 16.67 Z 52.53
α 88.31 β 0.00 γ 0.00
Eccentric (12)
X 0.00 Y 14.89 Z 50.48
α 88.35 β 0.00 γ 0.00
Eccentric (13)
X 0.00 Y 4.90 Z 50.19
α 88.35 β 0.00 γ 0.00
Eccentric (14)
X 0.00 Y 3.20 Z 50.14
α 88.35 β 0.00 γ 0.00
Eccentric (15)
X 0.00 Y 1.62 Z 50.10
α 88.35 β 0.00 γ 0.00
Eccentric (16)
X 0.00 Y 11.39 Z 50.38
α 124.25 β 0.00 γ 0.00
Eccentric (17)
X 0.00 Y 9.12 Z 56.68
α 173.24 β 0.00 γ 0.00
Eccentric (18)
X 0.00 Y 8.94 Z 58.17
α 153.24 β 0.00 γ 0.00
Eccentric (19)
X 0.00 Y 8.76 Z 59.66
α 173.24 β 0.00 γ 0.00.

Example 4
Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ -1000.00
1 ∞ (Eye) Eccentricity (1)
2 ASS [1] Eccentricity (2) 1.4924 57.6
3 FFS [1] Eccentricity (3) 1.4924 57.6
4 ASS [1] Eccentricity (2) 1.4924 57.6
5 FFS [2] 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 [3] Eccentricity (8) 1.4924 57.6
10 FFS [4] Eccentricity (9) 1.4924 57.6
11 FFS [5] Eccentricity (10) 1.4924 57.6
12 FFS [6] 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 [7] Eccentricity (16) 1.4924 57.6
19 ∞ Eccentricity (17)
20 ∞ Eccentricity (18)
Image plane ∞ Eccentricity (19)
ASS [1]
R -49.38
K 7.3241 × 10 ^-1
A -4.5432 × 10 ^-6
B 2.1489 × 10 ^-8
C -1.5676 × 10 ^-11
FFS [1]
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 [2]
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 [3]
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 [4]
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 [5]
C ₄ -1.4303 × 10 ^-2 C ₆ -1.5096 × 10 ^-2 C ₈ 4.7954 × 10 ^-5
C ₁₀ 2.6118 × 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 [6]
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 [7]
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
Eccentric (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
Eccentric (9)
X 0.00 Y 21.31 Z 58.89
α 144.17 β 0.00 γ 0.00
Eccentricity (10)
X 0.00 Y 28.58 Z 55.37
α 97.73 β 0.00 γ 0.00
Eccentric (11)
X 0.00 Y 15.06 Z 53.03
α 79.22 β 0.00 γ 0.00
Eccentric (12)
X 0.00 Y 14.26 Z 51.91
α 82.00 β 0.00 γ 0.00
Eccentric (13)
X 0.00 Y 12.58 Z 51.68
α 82.00 β 0.00 γ 0.00
Eccentric (14)
X 0.00 Y 2.67 Z 50.29
α 82.00 β 0.00 γ 0.00
Eccentric (15)
X 0.00 Y 1.11 Z 50.07
α 82.00 β 0.00 γ 0.00
Eccentric (16)
X 0.00 Y 9.11 Z 51.19
α 117.90 β 0.00 γ 0.00
Eccentric (17)
X 0.00 Y 6.15 Z 57.20
α 164.00 β 0.00 γ 0.00
Eccentric (18)
X 0.00 Y 5.65 Z 58.93
α 149.00 β 0.00 γ 0.00
Eccentric (19)
X 0.00 Y 5.32 Z 60.08
α 164.00 β 0.00 γ 0.00.

By the way, the single eccentric prisms 10 to 30 constituting the eyepiece optical system of the image display device of the present invention in the above embodiment are not limited to those having the number of internal reflections of 1 to 2 in the above embodiment, but various. An eccentric prism can be used. Examples thereof are shown in FIGS. In addition, it demonstrates by back ray tracing.

  In the case of FIG. 5, the prism P includes a first surface 112, a second surface 113, a third surface 114, and a fourth surface 115, and light incident through the pupil 111 is refracted by the first surface 112 and is prismatic. The light enters P, is internally reflected by the second surface 113, is internally reflected by the third surface 114, is incident on the fourth surface 115 and is refracted, and forms an image on the image surface 116.

  In the case of FIG. 6, the prism P includes a first surface 112, a second surface 113, a third surface 114, and a fourth surface 115, and light incident through the pupil 111 is refracted by the first surface 112 and is prismatic. Is incident on P, internally reflected by the second surface 113, again incident on the first surface 112, and then totally reflected, internally reflected by the third surface 114, incident on the fourth surface 115, and refracted. An image is formed on the image plane 116.

  In the case of FIG. 7, the prism P includes the first surface 112, the second surface 113, the third surface 114, and the fourth surface 115, and light incident through the pupil 111 is refracted by the first surface 112 and is prismatic. Incident P, internally reflected on the second surface 113, incident on the third surface 114, totally reflected, incident on the fourth surface 115, internally reflected, and incident again on the third surface 114, this time being refracted Then, an image is formed on the image plane 116.

  In the case of FIG. 8, the prism P is composed of the first surface 112, the second surface 113, and the third surface 114, and the light incident through the pupil 111 is refracted by the first surface 112 and enters the prism P. Internally reflected by the second surface 113, internally reflected by the third surface 114, again incident on the first surface 112, and then totally reflected, then incident again on the second surface 113, and then refracted. An image is formed on 116.

  In the case of FIG. 9, the prism P includes the first surface 112, the second surface 113, the third surface 114, and the fourth surface 115, and the light incident through the pupil 111 is refracted by the first surface 112 and is prismatic. Is incident on P, is internally reflected by the second surface 113, is incident on the third surface 114, is internally reflected, is incident again on the second surface 113, is internally reflected, is incident on the fourth surface 115, and is refracted. The image is formed on the image plane 116.

  In the case of FIG. 10, the prism P includes the first surface 112, the second surface 113, the third surface 114, and the fourth surface 115, and light incident through the pupil 111 is refracted by the first surface 112 and is prismatic. Is incident on P, is internally reflected by the second surface 113, is incident on the third surface 114, is internally reflected, is incident again on the second surface 113, is internally reflected, is incident on the fourth surface 115, and is internally reflected. Then, it is incident again on the second surface 113 and is refracted, and forms an image on the image surface 116.

  In the case of FIG. 11, the prism P includes the first surface 112, the second surface 113, and the third surface 114, and the light incident through the pupil 111 is refracted by the first surface 112 and enters the prism P, Internally reflected by the second surface 113, again incident on the first surface 112, and then totally reflected, then internally reflected by the third surface 114, incident on the first surface 112 three times, and totally reflected. Re-enters 114 and is refracted and forms an image on the image plane 116.

  In the case of FIG. 12, the prism P is composed of the first surface 112, the second surface 113, and the third surface 114, and the light incident through the pupil 111 is refracted by the first surface 112 and enters the prism P. Internally reflected by the second surface 113, again incident on the first surface 112 and then totally reflected, then internally reflected by the third surface 114, incident on the first surface 112 three times, totally reflected, and again third The light is incident on the surface 114 and internally reflected, and is incident on the first surface 112 four times and is refracted, and forms an image on the image surface 116.

The decentering prisms 10, 20, 30, and P shown in FIGS. 1 to 12 may be used alone as the eyepiece optical system 3, but as in the first embodiment, these decentering prisms 10, 20, 30, Two or more P may be used in combination as the eyepiece optical system 3. At this time, as in the first embodiment, the intermediate image may be formed once, the intermediate image may not be formed, or the intermediate image may be formed twice or more.

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

  First, FIG. 13 shows a state in which a head-mounted image display device for binocular mounting is mounted on the observer's head, and FIG. 14 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. 14 (the optical system of Example 2 is used), and the display optical system 100 and a reflective image display are used. As a portable image display device 102 such as a stationary or head-mounted image display device that can be observed with both eyes by preparing a pair of elements 101 on the left and right sides and supporting them separated by an eye radiant distance. It is configured.

  That is, the display device main body 102 uses the display optical system 100 as described above as an observation optical system, and the display optical system 100 is provided with a pair of left and right display systems. A reflective image display element 101 composed of elements is arranged. Then, as shown in FIG. 13, the display device main body 102 is provided with a temporal frame 103 as shown in the drawing that is continuous from the left and right, so that the display device main body 102 can be held in front of the observer's eyes. . In order to protect the first surface 11 (FIG. 2) of the prism 10 of the eyepiece optical system 100 of each image display device 102, the exit pupil of the eyepiece optical system 100 and the first surface 11 are protected as shown in FIG. A cover member 91 is disposed therebetween. As the cover member 91, any of a plane parallel plate, a positive lens, and a negative lens may be used.

  In addition, a speaker 104 is attached to the temporal frame 103 so that stereophonic sound can be heard along with image observation. In this way, the display device main body 102 having the speaker 104 is connected with a playback device 106 such as a portable video cassette via the audio / video transmission cord 105, so that the observer can attach the playback device 106 to the belt as shown in the figure. It can be held at an arbitrary position such as a place to enjoy video and audio. Reference numeral 107 in FIG. 13 denotes an adjustment unit such as a switch or a volume of the playback device 106. Note that electronic components such as video processing and audio processing circuits are built in the display device main body 102.

  The cord 105 may be attached to an existing video deck or the like with a jack at the tip. Further, it may be connected to a TV radio wave receiving tuner for TV viewing, or may be connected to a computer to receive computer graphics video, message video from the computer, or the like. In addition, in order to eliminate disturbing cords, an antenna may be connected and an external signal may be received by radio waves.

  Furthermore, the display optical system according to the present invention may be used for a one-eye head-mounted image display device in which an eyepiece optical system is disposed in front of either one of the left and right eyes. FIG. 15 shows a state in which the one-eye image display device is mounted on the observer's head (in this case, mounted on the left eye). In this configuration, a display device main body 102 comprising one set of the display optical system 100 and the reflective image display element 101 is attached to the front position of the corresponding eye of the front frame 108, and the front frame 108 is moved to the left and right. A temporal frame 103 as shown in the figure is provided continuously so that the display device main body 102 can be held in front of one eye of the observer. Other configurations are the same as those in FIG. 13, and a description thereof will be omitted.

By the way, in the head-mounted image display device for binocular or single-eye wearing according to the present invention as described above, in order to enable the external image to be observed simultaneously with the display image or the display image and the external image can be selectively observed. As shown in FIG. 14, the reflecting surface 12 facing the exit pupil of the decentering prism 10 constituting the display optical system 100 is a semi-transmissive reflecting surface, and is in contact with or slightly spaced from the semi-transmissive reflecting surface 12. It is desirable to arrange another decentering prism 80 that compensates for the declination angle or power due to 10 and allows the outside to be observed through the two decentering prisms 10 and 80. In that case, a shutter 81 such as a liquid crystal shutter that blocks or transmits external light indicated by a broken line is arranged on the incident side (the side opposite to the eyes of the observer) of another eccentric prism 80, and the shutter It is desirable that 81 be opened so that an external image can be observed (see-through), or a superimposed image of an external image and a display image can be observed, and the shutter 81 can be closed so that the display image of the display element 101 can be observed.

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

[1] Reflective image display means for displaying an image by reflecting an illumination light beam incident from the front side of a display surface on which an image to be observed is formed, and illumination light is incident on the display surface of the reflective image display means An image display device comprising: a light splitting element to be guided; and an eyepiece optical system that guides an image displayed on a display surface of the reflective image display unit to a pupil position where an eyeball of an observer should be positioned.
The light splitting element includes a transflective surface that separates an observation optical path and an illumination optical path, and the transflective surface is formed in a rotationally asymmetric curved shape that gives positive power to an illumination light beam from an illumination light source. An image display device characterized by comprising:

    [2] The image display apparatus according to [1], wherein the light splitting element is formed of a prism member, and the transflective surface is provided in a transparent medium having a refractive index of the prism member greater than 1.

[3] Reflective image display means for displaying an image by reflecting an illumination light beam incident from the front side of a display surface on which an image to be observed is formed, and illumination light is incident on the display surface of the reflective image display means An image display device comprising: a light splitting element to be guided; and an eyepiece optical system that guides an image displayed on a display surface of the reflective image display unit to a pupil position where an eyeball of an observer should be positioned.
An image display comprising: an illumination light source disposed at a position closer to the light splitting element than a position conjugate with the pupil position via the eyepiece optical system, the reflective image display means, and the light splitting element apparatus.

[4] The optical axis is a light beam that exits from the center of the illumination light source, reflects off the center of the display surface of the reflective image display means, and reaches the center of the pupil position, and the optical axis is the light of the light splitting element. When N is a point that intersects the dividing plane, P is a point that intersects the position conjugate with the pupil position, L is a point that intersects the illumination light source, and α is a value obtained by dividing the optical path length NL by the optical path length NP.
0.5 <α <0.9 (3)
4. The image display device as described in 3 above, wherein

    [5] The light splitting element includes a transflective surface as a light splitting surface, and the transflective surface is formed in a rotationally asymmetric curved surface shape that gives positive power to the illumination light beam from the illumination light source. 5. The image display device as described in 3 or 4 above.

[6] Reflective image display means for displaying an image by reflecting an illumination beam incident from the front side of a display surface on which an image to be observed is formed, and illumination light is incident on the display surface of the reflective image display means An image display device comprising: a light splitting element to be guided; and an eyepiece optical system that guides an image displayed on a display surface of the reflective image display unit to a pupil position where an eyeball of an observer should be positioned.
The image display device, wherein the light splitting element is formed of a prism member, and the illumination light source surface is inclined with respect to the illumination light incident surface of the prism member.

[7] An angle formed by the illumination light incident surface of the prism member and the illumination light source surface is β, and a distance between the illumination light incident surface and the illumination light source surface is close to the display surface of the illumination light incident surface. When we define that β is positive when it becomes narrower on the side,
2 ° <β <30 ° (4)
7. The image display device as described in 6 above, wherein

[8] The optical axis is a light beam that exits from the center of the illumination light source, reflects off the center of the display surface of the reflective image display means, and reaches the center of the pupil position, and the optical axis is the light of the light splitting element. N is a point that intersects the dividing plane, P is a point that intersects with the pupil position via the eyepiece optical system, the reflective image display means, and the light dividing element, and L is a point that intersects the illumination light source surface. When a value obtained by dividing the optical path length NL by the optical path length NP is α,
0.5 <α <0.9 (3)
8. The image display device as described in 6 or 7 above, wherein

    [9] The light splitting element includes a transflective surface as a light splitting surface, and the transflective surface is formed in a rotationally asymmetric curved shape that gives positive power to the illumination light beam from the illumination light source. 9. The image display device as set forth in any one of 6 to 8, wherein:

[10] When the deflection angle of the optical axis of the illumination light from the illumination light source by the light splitting element is θ,
94 ° <θ <120 ° (5)
10. The image display device as described in any one of 1 to 9 above, wherein:

    [11] The image display device as described in any one of [1] to [10], wherein a cover member of the reflection type image display means and the light splitting element are joined with an optical adhesive.

    [12] Wobbling the display surface of the reflective image display element in a one-dimensional direction or in a two-dimensional direction with an optical adhesive between the cover member of the reflective image display means and the light splitting element. 12. The image display device according to any one of 1 to 11 above, wherein a wobbling element is joined.

    [13] The wobbling element for wobbling the display surface of the reflective image display element in a one-dimensional direction or a two-dimensional direction is bonded to the eyepiece optical system side of the light splitting element with an optical adhesive. The image display device according to any one of 1 to 11.

  As is apparent from the above description, according to the present invention, in an image display apparatus using a reflective image display element, power is applied to the light dividing surface of the light dividing element that makes illumination light incident on the display surface of the reflective image display means. By reducing the thickness of the light splitting element in the optical axis direction, the light converging element can be omitted, uniform illumination is possible, and a compact image display device can be configured with a small number of parts. In addition, the aberration is determined only by the accuracy of the parts, and the accuracy when the image display apparatus is assembled becomes loose.

1 ... exit pupil 2 ... axial principal ray (optical axis)
3 ... eyepiece optical system 4 ... light splitting element 5 ... display surface 6 ... light source surface 7 ... plane conjugate to exit pupil (incidence pupil)
8 ... Wobbling elements 10, 20, 30 ... Decentered prisms 11, 21, 31 ... First surface 12, 22, 32 ... Second surfaces 13, 23, 33 ... Third surface 34 ... Fourth surface 40 ... Light splitting surface ( Transflective surface)
41, 42 ... Transparent medium 43 ... Illumination light incident surface 44 ... Emission surface 45 ... Image display element facing surface 51 ... Cover glass 80 ... Eccentric prism 81 ... Shutter 91 ... Cover member 100 ... Display optical system 101 ... Reflective image display Element 102: Image display device (display device body)
103 ... Temporal frame 104 ... Speaker 105 ... Audiovisual transmission code 106 ... Playback apparatus 107 ... Adjusting unit 108 ... Front frame 111 ... Pupil 112 ... First surface 113 ... Second surface 114 ... Third surface 115 ... Fourth surface 116 ... image plane P ... eccentric prism

Claims (1)

Reflective image display means for displaying an image by reflecting an illumination light beam incident from the front side of a display surface on which an image for observation is formed, and light splitting for making illumination light incident on the display surface of the reflective image display means In an image display device comprising: an element; and an eyepiece optical system that guides an image displayed on the display surface of the reflective image display means to a pupil position where an observer's eyeball should be positioned.
An image display comprising: an illumination light source disposed at a position closer to the light splitting element than a position conjugate with the pupil position via the eyepiece optical system, the reflective image display means, and the light splitting element apparatus.

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