JP2002162598A - Observation optical system and imaging optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an observation optical system or imaging optical system which can be made as small as, being usable for a portable telephone and portable information terminal as well as a virtual image observation apparatus of a head-worn type, is light in weight and bright, has moreover high resolution and is easily manufactured. SOLUTION: A prism 4 and a light transmitting plate 3 are arranged inclusively between a pupil plane 1 and an image plane 5. The light transmission plate 3 has holographic elements (HOEs) 61 to 64 on both surfaces respectively of an incident region and of an exit region, and totally reflect luminous fluxes >=10 times inside the light transmitting plate. The HOEs 61 and 62 are formed so as to respectively diffract the incident luminous fluxes, until the incident angles attain angles which exceed the total reflection critical angle of the light transmitting plate. HOEs 63 and 64 are formed so as to respectively diffract the luminous fluxes introduced to the exit region, until the incident angles attain the angles do not exceed the total reflection critical angle of the light transmitting plate. The prism 4 has a curved surface for correcting the eccentric aberrations of the luminous fluxes, emitted from the light transmitting plate 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an observation optical system and an imaging optical system, and more particularly, to an observation optical system and an imaging optical system which can be held on the head or face of an observer, or can be added to a portable telephone or a portable information terminal. The present invention relates to an optical system used for an image display device and an imaging device such as a camera.

[0002]

2. Description of the Related Art In recent years, an image display device, particularly an image display device of a type worn on the head or face, has been actively developed for the purpose of allowing individuals to enjoy a large-screen image. In recent years, with the spread of mobile phones and mobile information terminals, there has been an increasing need to view images and character data of mobile phones and mobile information terminals on a large screen.

As a light guide device that can be used as a part of such a device, a light guide device using a hologram has been conventionally proposed in Japanese Patent Application Laid-Open No. H5-224018. Also,
An image display device using a hologram is disclosed in
No. 022, JP-A-8-113059 and U.S. Pat. No. 4,711,512.

[0004]

However, Japanese Patent Laid-Open Publication No.
In the case of the light guide device described in Japanese Patent No. 24018, one HO
With the E element, the diffraction angle per HOE element is increased because the light is diffracted only once each in the incident area or the incident area and the emission area. For this purpose, it is necessary to reduce the pitch of the stripes in the HOE, the allowable vibration width at the time of exposure becomes small, the positional accuracy of the exposure optical system becomes strict, and the maximum allowable exposure of the photosensitive material for HOE exposure is performed. Manufacturing is difficult because higher frequencies are required.

In the case of the image display device described in JP-A-6-250022, one HOE element is used.
Since the light is diffracted only once each in the incident area and the emission area, the diffraction angle per HOE element becomes large, and it is difficult to manufacture. In addition, since the optical system of the image display device has a non-coaxial optical system, an eccentric aberration is generated. However, it is difficult to correct the generated eccentric aberration only with a small number of HOE surfaces. In addition, since the number of times of total reflection is as small as about two, in order to guide light over a long distance in the length direction of the light guide plate while keeping the light guide plate thin,
The thickness of the light guide plate must be increased. Further, the optical system of the image display device does not constitute a relay optical system, that is, does not form an intermediate image in the optical system. Can not get.

In the case of the image display device disclosed in Japanese Patent Application Laid-Open No. H8-113059 or US Pat. No. 4,711,512,
One HOE element is arranged in each of the incident area and the emission area.
Since diffraction is performed by the HOE element only every time,
It becomes necessary to increase the diffraction angle per OE element,
Difficult to manufacture. In addition, since the optical system is a non-coaxial optical system, eccentric aberration occurs. However, it is difficult to correct the generated eccentric aberration with only a small HOE surface. further,
In U.S. Pat. No. 4,711,512, total reflection is performed six times. At such a total number of times of reflection, light is guided over a long distance in the length direction of the light guide plate while keeping the light guide plate thin. Therefore, the thickness of the light guide plate must be increased. Furthermore, since the image display device is not a relay optical system, a wide viewing angle cannot be obtained if the image display device is configured using a smaller image display device.

Accordingly, the present invention provides a compact, lightweight, bright, high-resolution, and high-resolution device that can be used in portable telephones, portable information terminals, and head-mounted virtual image observation devices. It is an object of the present invention to provide an observation optical system or an imaging optical system that is easy to perform.

[0008]

An optical system according to the present invention is an optical system arranged between a pupil plane and an image plane, wherein the optical system includes at least a prism and a light guide plate. The light guide plate has holographic elements on both surfaces in the incident area and the exit area, and is configured to totally reflect the light flux 10 times or more inside the light guide plate from the incident area to the exit area, The holographic elements provided on both sides of the incident area of the light guide plate diffract light beams incident at a predetermined wavelength at predetermined positions, and the incident angle of the light beam is the total reflection critical angle of the light guide plate. The holographic elements formed so as to have an angle exceeding the angle and provided on both surfaces of the emission area of the light guide plate, the luminous flux guided from the incidence area to the emission area at a predetermined position, respectively. Each is diffracted, the incident angle of the light beam is an angle not exceeding the critical angle of total reflection of the light guide plate, and the light guide plate is formed so that the light beam is emitted from the light guide plate, and the prism is formed on at least one surface. It is characterized by having a curved surface for correcting eccentric aberration of the light beam emitted from the light guide plate.

Further, when the present invention is configured as an observation optical system, an image display element for displaying an image to be observed by an observer is arranged on the image plane, and an eyeball of the observer is located on the pupil plane. The exit pupil is formed as described above, and the luminous flux emitted from the image display element passes through the prism, enters the first region of the light guide plate, and is provided on the prism side of the light guide plate. Permeate the holographic element, is diffracted and reflected by the holographic element provided on the opposite side of the prism of the light guide plate, is diffracted and reflected by the diffractive element provided on the prism side of the light guide plate, Become an angle exceeding the total reflection critical angle of the light guide plate,
While being totally reflected 10 times or more inside the light guide plate, it heads toward the second region of the light guide plate, and is diffracted and reflected by the holographic element provided on the exit pupil side of the light guide plate in the second region. The light is diffracted and reflected by the holographic element provided on the opposite side of the light guide plate from the exit pupil, and has an angle that does not exceed the total reflection critical angle of the light guide plate. It is preferable that the light passes through the holographic element provided in the light guide plate and exits from the light guide plate to be guided to the exit pupil.

When the optical system of the present invention is configured as an image pickup optical system, an image pickup device for picking up an object image is arranged on the image plane, and the brightness of a light beam from the object is narrowed on the pupil plane. A brightness stop is arranged, and a light flux from an object that has passed through the brightness stop is incident on a second region of the light guide plate and passes through the holographic element provided on the object side of the light guide plate. The light guide plate is diffracted and reflected by the holographic element provided on the side opposite to the object, and the light guide plate is diffracted and reflected by the holographic element provided on the object side of the light guide plate. An angle exceeding the reflection critical angle, the light is directed toward the first region while being totally reflected 10 times or more inside the light guide plate, and the hollow provided on the prism side of the light guide plate in the first region Graphic element Diffracted and reflected, diffracted and reflected by the holographic element provided on the side of the light guide plate opposite to the prism, and transmitted through the diffraction element provided on the prism side and emitted from the light guide plate, It is preferable that the light is guided to the image pickup device via a prism.

The basic principle of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual diagram of an optical system according to the present invention, FIG. 2 is a principle explanatory view showing a reflection state of light incident on a light guide plate constituting the optical system according to the present invention, and FIG. It is a conceptual diagram for explaining the state where an intermediate image is formed inside the light guide plate. Note that, for convenience of explanation, it is assumed that ray tracing is performed from the right side of the figure.

As shown in FIG. 1, the optical system of the present invention has a light guide plate 3 and an eccentric prism 4 between a pupil plane 1 and an image plane 5. As shown in FIG. 2, the light guide plate 3 is provided with a first HOE (volume holographic element) and a second HOE as diffractive elements on both surfaces of an incident region of the base glass, and diffracts light on both surfaces of an emission region. A third HOE as an element,
Fourth HOEs are provided. Note that a transparent plastic may be used instead of the transparent glass as the base.

Here, the reflection state of the on-axis light of a predetermined wavelength incident on the second HOE provided on the light guide plate at an incident angle smaller than the critical angle in the light guide plate will be described.
This will be described using light that is perpendicularly incident on. 2nd HOE
Is vertically incident on the first HOE as it passes through the second HOE as it is. The first HOE has an angle selectivity so as to diffract and reflect the light incident at the first incident angle at the incident position Q1, and diffracts and reflects the incident light. Light diffracted and reflected by the first HOE is incident on the second HOE at a second angle of incidence. The second HOE has an angle selectivity so as to diffract and reflect light incident at the second incident angle at the incident position Q2, and diffracts and reflects the incident light.

The light diffracted and reflected by the second HOE has a third angle of incidence exceeding the critical angle with respect to the light guide plate, and is reflected by the first HOE.
It is incident on the OE. The first HOE totally reflects light incident at a third incident angle exceeding the critical angle at the incident position Q3. The totally reflected light similarly enters the second HOE at a third angle of incidence that exceeds the critical angle. The second HOE totally reflects light incident at a third incident angle exceeding the critical angle at the incident position Q4. The totally reflected light is thereafter guided to a predetermined position of the fourth HOE provided in the emission area by repeating the same total reflection on the base surface made of glass or plastic on both sides and the HOE provided on the base surface. .

The fourth HOE has an angle selectivity so as to diffract and reflect light incident at a predetermined position Qm at a third incident angle exceeding the critical angle, and diffracts and reflects this incident light. I do. The light diffracted and reflected by the fourth HOE has a fourth incident angle with respect to the light guide plate, and the third HOE
Incident on. The third HOE has an angle selectivity so as to diffract and reflect light incident at a fourth incident angle at the incident position Qn, and diffracts and reflects the incident light. The light diffracted and reflected by the third HOE is incident on the fourth HOE at a fifth incident angle below the critical angle with respect to the light guide plate (perpendicular in FIG. 2, that is, at an incident angle of 0 degree). The light guide plate is emitted through the 4HOE.

As described above, if the light is diffracted twice by the separate HOEs in the incident area of the light guide plate and is also diffracted twice by the separate HOEs in the exit area, the diffraction angle per one time does not increase. Only

Generally, a diffractive optical element having a large diffraction angle is
It is known that the pitch of the lattice structure provided inside the element becomes finer, which makes production difficult. In the optical system of the present invention,
As described above, since a plurality of HOE elements are arranged in each of the incident area and the emission area of the light guide plate, it is possible to suppress the diffraction angle per one time of the HOE element from becoming large, and it is possible to suppress the interference fringe in the HOE. Pitch can be increased. Further, the allowable vibration width at the time of exposure is reduced, and the positional accuracy of the exposure optical system is also reduced. Further, it is possible to use a photosensitive material for HOE exposure which has a lower maximum exposure frequency required.

The light guide plate as shown in FIG. 2 is configured as a decentered optical system in which a rotationally asymmetric optical action surface is disposed for miniaturization and the optical axis is bent. Since the HOE element having a rotationally asymmetric optical action is arranged to cause the light to be totally reflected, guided to a predetermined position, and emitted after the light is made incident, large eccentric aberrations will be generated as it is. Therefore, in the present invention, as shown in FIG. 1, an eccentric prism having a free-form surface on at least one surface is arranged outside the light guide plate so that eccentric aberration generated via the light guide plate can be corrected. I have.

If the number of total reflections inside the light guide plate is 10 or more as in the optical system of the present invention, the light guide plate is kept thin and light is guided over a long distance. be able to. Further, it is more preferable that the number of total reflections in the light guide plate is 20 or more,
It is more preferable that the number of times is equal to or more than the number of times.

It is preferable that the optical system of the present invention is configured as a relay optical system that forms an intermediate image in the light guide plate with the incident light beam. FIG. 3 shows a simplified concept of the relay optical system of the present invention. In FIG.
For convenience of explanation, one light guide plate is shown as having a light guide plate in an incident area and a light guide plate in an emission area, and total reflection of light rays is omitted. Further, the description will be made on the assumption that the axial light beam enters the upper right light guide plate. The axial luminous flux from the exit pupil incident on the light guide plate incident area is diffracted and reflected twice through the HOEs provided on both sides of the light guide plate incident light, and then forms an image at an intermediate image forming position on the way. The light enters the emission region of the light guide plate, is diffracted and reflected twice through the HOEs provided on both sides of the emission region of the light guide plate, exits from the emission region of the light guide plate, and enters the eccentric prism.

As described above, if the optical system of the present invention is configured as a relay optical system that forms an intermediate image of the incident light beam from the incident area to the emission area of the light guide plate, the optical system on the eyepiece side generates Can be corrected by the optical system closer to the image than the intermediate image position of the relay optical system, and the relay optical system projects a large image display element onto the intermediate image plane, which results in an apparently large image. It becomes optically equivalent to one using the display element in the eyepiece optical system. Thus, a wide viewing angle can be obtained even when a small image display element is used. On the other hand, if the image display device is configured with only the eyepiece optical system without configuring the relay optical system as in the above-described conventional optical system, in order to achieve a wide viewing angle of view, the power of the eyepiece optical system must be reduced. It is necessary to increase the magnification, that is, shorten the focal length, and increase the power of the eyepiece optical system. Therefore, configuring the optical system of the present invention by a relay optical system is useful for preventing these problems. As long as an intermediate image can be formed, any optical element such as a prism or a lens may be used to configure the relay optical system.

As described above, in the optical system of the present invention shown in FIG. 1, the light beam incident on the inside of the light guide plate 3 is repeatedly reflected at least twice in the incident area, and is repeatedly subjected to total reflection. After forming an image at the image position, the light is guided to the emission area while repeating total reflection. The light is diffracted and reflected at least twice in the emission area and emitted from the emission area.
The incident from the first surface 4 _1, the second surface 4 _2, is reflected by the third surface 4 _3, after emitted from the fourth surface 4 _4, is configured to image at the image plane position.

In the optical system of the present invention, the pupil diameter is set to PD (P
upil Diameter), eye relief ER
When (Eye Relief) is satisfied, it is preferable that the following conditional expression (1) is satisfied. 0.1 ≦ PD ≦ ER × 0.9 (1) When the pupil diameter PD becomes smaller than the lower limit and becomes small, it becomes difficult to observe and capture a high-resolution image due to the influence of diffraction. On the other hand, if the pupil diameter PD becomes larger than the upper limit, the pupil diameter becomes too large, and it becomes difficult to correct aberrations, and the optical system is further enlarged.

The optical system according to the present invention provides the following conditional expression (2):
It is more desirable to satisfy 1.0 ≦ PD ≦ ER × 0.6 (2) The meanings of the upper and lower limits of conditional expression (2) are the same as in conditional expression (1).

Further, the optical system according to the present invention provides the following conditional expression (3):
It is even more desirable to satisfy 1.0 ≦ PD ≦ ER × 0.3 (3) The meanings of the upper and lower limits of the conditional expression are the same as those of the conditional expression (1).

It is preferable that the optical system of the present invention satisfies the following conditional expression (4), where L is the distance from the incident position to the exit position of the axial chief ray in the light guide plate. 30.0 mm ≦ L ≦ 200.0 mm (4) If the distance L is less than the lower limit and the optical system such as an eccentric prism is provided on the light guide plate on the face side of the observer, the distance of the observer may be reduced. If the optical system interferes with the face, and if an optical system such as an eccentric prism is provided on the light guide plate on the side facing the observer's face, the optical system blocks see-through observation. I will. On the other hand, when the distance L is longer than the upper limit, the device becomes too large, the weight becomes heavy, and it becomes difficult to mount it on the head.

The optical system according to the present invention provides the following conditional expression (5):
It is more desirable to satisfy 35.0 mm ≦ L ≦ 140.0 mm (5) The meanings of the upper and lower limits of conditional expression (5) are the same as those of conditional expression (4).

Further, the optical system of the present invention provides the following conditional expression (6):
It is even more desirable to satisfy 40.0 mm ≦ L ≦ 70.0 mm (6) The meanings of the upper and lower limits of conditional expression (6) are the same as described above.

The optical system of the present invention is applicable to both cases where the pupil plane and the image plane are located on the same plane side of the light guide plate and where the pupil plane and the image plane are located with the light guide plate separated. It is possible.

The image display device used in the observation optical system of the present invention may be of either a transmission type or a reflection type.

In the optical system according to the present invention, when the image display device is constituted by the reflection type image display device, an illumination light source is provided, and the illumination light from the illumination light source is transmitted to the reflection type image display device. It is preferable that the light is guided to a display element, and further, the light flux reflected by the reflective image display element is guided to an incident area of the light guide plate.

Incidentally, in the optical system of the present invention, as shown in FIG. 2, the holographic fixture elements are provided separately in the incident area and the emission area on each side of the light guide plate. A holographic element is integrally formed on each side of the light guide plate from the incident area to the emission area, and the luminous flux in the area from the predetermined position of the incidence area to the predetermined position of the emission area is completely The light guide plate may be totally reflected 10 times or more at an angle exceeding the reflection critical angle.

Further, in the observation optical system of the present invention, an image pickup device is provided on the opposite side of the light guide plate from the exit pupil, and an image of an observer when an eyeball is located at the exit pupil position is provided. You may comprise so that it may image through a light plate.

In the optical system according to the present invention, the holographic element is a volume hologram (HO) as described above.
It is preferable to comprise E).

In the optical system according to the present invention, it is preferable that the light guide plate is formed in a planar shape. In addition,
The surface shape of the light guide plate may be formed in a curved shape.

In the present invention, if the light guide plate is formed in a curved shape having a curvature in one direction, the entire optical system can be further reduced in size.

Incidentally, the photosensitive material for a volume hologram element supplied in the form of a flat film can be relatively easily bent into a cylindrical shape, but can be bent in the X and Y directions.
It is difficult to machine into a base shape having a curvature in both directions at the same time. Therefore, if the plate surface of the light guide plate is formed in a planar shape and the volume hologram is arranged on the planar base, a configuration that can be easily manufactured can be obtained.

The volume hologram is attached to the base surface or embedded in the base surface so as to be flush with the base surface.

The surface of the prism for correcting the eccentric aberration is desirably a rotationally asymmetric surface such as a free-form surface in order to achieve rotationally asymmetric distortion correction and an optical system having good telecentricity. , A rotationally symmetric surface such as an anamorphic surface.

In the observation optical system of the present invention, the volume hologram is not limited to the above-mentioned reflection type HOE. For example, in FIG.
E or using a transmission type HOE for the fourth HOE in the emission area,
The light may be transmitted by diffraction.

Incidentally, these configurations of the optical system of the present invention are as follows.
As described above, application to not only the observation system but also the imaging system is possible. That is, in the observation optical system of the present invention, an image display element for displaying an image observed by an observer, and an exit pupil,
In the imaging optical system of the present invention, an imaging element that captures an object image,
And a brightness stop for reducing the brightness of the light beam from the object. And also in the imaging optical system,
It is preferable to adopt a configuration according to the observation optical system such as the above-mentioned conditional expression.

In addition, the optical system of the present invention is preferably covered with a dustproof member. With such a configuration, it is possible to prevent dust and the like from being enlarged and observed. In the light guide plate having a holographic element,
The dustproof member can prevent the holographic element from expanding due to the intrusion of moisture from the outside into the holographic element and changing the peak wavelength of diffraction. In this case, the dustproof member preferably includes a box body that covers the outside and a transparent cover that transmits light passing between the light guide plate and the pupil surface. In that case, the transparent cover
It may be constituted by a transparent member formed of glass or plastic or the like.

Further, an image display element, a main body in which any of the above-described observation optical systems according to the present invention is arranged as an eyepiece optical system, and an exit pupil of the observation optical system is held at an eyeball position of an observer. As described above, the head-mounted image display device can be configured to include the support member that supports the main body portion on the observer's head and the speaker member that provides sound to the observer's ear.

In this case, in the head mounted image display device, the main body includes an observation optical system for the right eye and an observation optical system for the left eye, and the speaker member includes a speaker member for the right ear. You may comprise so that it may have a speaker member for left ears.

Further, in this head-mounted image display device, the speaker member may be constituted by an earphone.

In the optical system according to the present invention, the prism passes through the center of the object point through the backward ray tracing in the observation optical system, the forward ray tracing in the imaging optical system, the exit pupil in the observation optical system, and the brightness in the imaging optical system. When a light ray passing through the center of the stop and reaching the center of the image plane is defined as an axial chief ray, if at least one reflecting surface is not decentered with respect to the axial chief ray, the incident ray of the axial chief ray is The reflected light rays pass through the same optical path, and the axial chief rays are blocked in the optical system. As a result, an image is formed only by the light flux whose central portion is shielded, and the center becomes dark or the image is not formed at the center at all. Therefore, an eccentric prism is used as the prism used in the present invention.

When the reflecting surface with power is decentered with respect to the axial principal ray, at least one of the surfaces constituting the prism member used in the present invention is a rotationally asymmetric surface. Is desirable. Among them, it is particularly preferable that at least one reflecting surface of the prism member is a rotationally asymmetric surface in terms of aberration correction.

It is necessary to decenter the optical system in order to bend the optical path and use the optical path of the common area redundantly.
However, if the optical system is an eccentric optical system in order to bend the optical path in this way, eccentric aberrations such as rotationally asymmetric distortion and rotationally asymmetric field curvature are generated. To correct this eccentric aberration, a rotationally asymmetric surface is used as described above.

It is desirable that the surface of the holographic element used in the present invention is a rotationally asymmetric surface for the same reason. The base surface on which the holographic element is provided is desirably a planar shape as described above. However, a cylindrical surface, a spherical surface, an aspheric surface, an anamorphic surface, a toric surface, a surface having only one symmetric surface, and a plane-symmetric free-form surface It may be formed in any of the shapes.

The rotationally asymmetric surface used in the present invention is:
It can be constituted by a plane-symmetric free-form surface having only one anamorphic surface, toric surface and symmetry surface. In addition,
Preferably, a free-form surface having only one plane of symmetry may be used.

In the present invention, the on-axis principal ray is traced by a ray that passes through the center of the exit pupil and reaches the center of the image display element in the observation optical system, and is traced by the reverse ray. Are defined by forward ray tracing with rays reaching the center of the image sensor through the center of the image sensor. Then, the axial chief ray moves from the center of the exit pupil or the aperture stop to the HO of the incident area of the light guide plate.
Let the optical axis defined by the straight line to intersect the E plane be Z
An axis, and an axis perpendicular to the Z axis and within an eccentric plane of each surface constituting the light guide plate is defined as a Y axis.
An axis orthogonal to the Z axis and orthogonal to the Y axis is defined as an X axis. The center of the exit pupil or the aperture stop is the origin of the coordinate system in the observation optical system or the imaging optical system of the present invention. Also, in the present invention, surface numbers are assigned by reverse ray tracing from the exit pupil to the image display element as described above, or by forward ray tracing from the aperture stop to the image pickup element, and the axial chief ray is the exit pupil. A direction from the aperture to the image display element or a direction from the aperture stop to the image sensor is the positive direction of the Z axis; the direction of the Y axis toward the image display element or the direction of the Y axis toward the image sensor is the positive direction of the Y axis; X that constitutes the right-handed system with the axis, Z axis
The direction of the axis is defined as the positive direction of the X axis. Here, the free-form surface used in the present invention is defined by the following equation (7). Note that the Z axis of the definition formula is the axis of the free-form surface.

[0052] (7) where the first term in the equation (7) is a spherical term, and the second term is a free-form surface term. In the spherical term, C is the curvature of the vertex, k is the conic constant (cone constant), and r = √ (X ² + Y ² ).

The free-form surface term can be expanded as in the following equation (8). (8) where C _j (j is an integer of 2 or more) is a coefficient.

The free-form surface is generally an XZ surface,
Although neither YZ plane has a symmetry plane, in the present invention, by setting all odd-order terms of X to 0, YZ
It is a free-form surface having only one symmetric surface parallel to the surface.
Such a free-form surface is, for example, 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, C 31, C 33, C 35 ··
It can be achieved by setting the coefficient of each term of 0 to 0.

By setting all odd-numbered terms of Y to 0, a free-form surface having only one symmetric surface parallel to the XZ plane is obtained. Such a free-form surface is, for example, 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, the coefficient of each term of C _34, C ₃₆ · · · can be achieved by zero.

Further, any one of the directions of the above-mentioned symmetry plane is defined as a symmetry plane, and the eccentricity in the direction corresponding thereto, 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 setting the eccentric direction of the optical system to the X-axis direction with respect to a symmetric plane parallel to the XZ plane, it is possible to effectively correct rotationally asymmetric aberrations caused by the eccentricity while improving productivity. It becomes possible.

Further, the above-mentioned definition equation (7) is obtained by
In the present invention, a rotationally asymmetric surface having only one plane of symmetry is used to correct rotationally asymmetric aberrations caused by eccentricity, and at the same time improve the manufacturability. But the above defined expression
It goes without saying that the same effect can be obtained for any other definition formula other than (7).

In the present invention, the shape of the reflecting surface provided on the prism member may be a plane-symmetric free-form surface having only one symmetric surface.

The shape of the anamorphic surface is given by the following equation.
Defined by (9). Note that a straight line passing through the origin of the surface shape and perpendicular to the optical surface is the axis of the anamorphic surface. ^{Z = (Cx · X 2 +} Cy · Y 2) / [1+ {1- (1 + Kx) Cx 2 · X 2 - (1 + Ky) Cy 2 · Y 2} 1/2] + ΣRn {(1-Pn) X 2 + (1 + Pn) Y ² ｝ ^{(n + 1)} (9)

Here, assuming that n = 4 (fourth-order term) as an example, the above equation (9) can be expressed by the following equation (10) when expanded. ^{Z = (Cx · X 2 +} Cy · Y 2) / [1+ {1- (1 + Kx) Cx 2 · X 2 - (1 + Ky) Cy 2 · Y 2} 1/2] + R1 {(1-P1) X 2 + ^{(1 + P1) Y 2}} 2 + R2 {(1-P2) X 2 + (1 + P2) Y 2} 3 + R3 {(1-P3) X 2 + (1 + P3) Y 2} 4 + R4 {(1-P4) X 2 + (1 + P4) Y ² ｝ ⁵ (10) where Z is the deviation from the tangent plane to the origin of the surface shape, Cx is the curvature in the X-axis direction, Cy is the curvature in the Y-axis direction, and Kx is the cone coefficient in the X-axis direction. , Ky are the Y-axis direction conical coefficients, Rn is the rotationally symmetric component of the spherical term, and Pn is the rotationally asymmetric component of the aspherical term. The radius of curvature Rx in the X-axis direction and the radius of curvature R in the Y-axis direction
y and the curvatures Cx, Cy have a relationship of Rx = 1 / Cx, Ry = 1 / Cy.

The toric surface includes an X toric surface and a Y toric surface, which are defined by the following equations (11) and (12), respectively. A straight line passing through the origin of the surface shape and perpendicular to the optical surface is the axis of the toric surface. The X toric surface is given by the following equation (1
Defined in 1). F (X) = Cx · X 2 / [1+ {1- (1 + K) Cx 2 · X 2} 1/2] + AX 4 + BX 6 + CX 8 + DX 10 ······ Z = F (X) + ( 1/2) Cy {Y ² + Z ² −F (X) ² } (11) The Y toric surface is defined by the following equation (12). F (Y) = Cy · Y ² / [1+ {1− (1 + K) Cy ² · Y ² ｝ ^1/2 ] + AY ⁴ + BY ⁶ + CY ⁸ + DY ¹⁰ ... Z = F (Y) + ( 1/2) Cx {X ² + Z ² −F (Y) ² } (12) where Z is the amount of deviation of the surface shape from the tangent plane to the origin, Cx is the curvature in the X-axis direction, and Cy is the Y-axis direction. The curvature, K is a conical coefficient, and A, B, C, and D are aspherical coefficients. Note that X
Axial radius of curvature Rx, Y-axis radius of curvature Ry and curvature C
x and Cy have a relationship of Rx = 1 / Cx and Ry = 1 / Cy.

The holographic element includes a relief hologram and a volume hologram. Relief-type holograms have low incident angle selectivity and wavelength selectivity, and diffract light at a specific incident angle and wavelength to form an image as the required order light. It has the property that it is diffracted in a state where the efficiency is reduced, and forms an image as unnecessary-order light. On the other hand, volume holograms have high incidence angle selectivity and wavelength selectivity, diffract only light of a specific wavelength and incident angle to form an image as a required order light, and most other light is assumed to be a zero order light. It has the property of being transmitted or reflected and making it difficult to image unnecessary order light. Therefore, if a reflection type volume hologram is used as the holographic element used for the first prism as in the present invention, it is possible to prevent the occurrence of image blur due to unnecessary order light, and to obtain a clear observation image.

The volume hologram (HOE), which is a holographic element in the present invention, is defined as follows. FIG. 36 is a principle diagram for defining the HOE in the present invention. First, ray tracing of a wavelength λ that enters and exits the HOE surface is performed by using an optical path difference function Φ ₀ on the HOE surface defined with respect to a reference wavelength λ ₀ = HWL.
It is given by the following equation (13). _{n d Q d · N = n} i Q i · N + m (λ / λ 0) ∇Ф 0 · N ...... (13) However, the normal vector of N is HOE surface, n _i (n _d) is incident side ( The refractive index Q _i (Q _d ) on the exit side is an incident (exit) vector (unit vector). M = HOR is the diffraction order of the emitted light.

The HOE is a two-point light source having a reference wavelength λ ₀ , that is, a point P ₁ = (HX1, HY1, HZ) as shown in FIG.
The object light with 1) as the light source, and the point P ₂ = (HX2, H
Y2, HZ2) are manufactured (defined) by interference of reference light with the light source as: Φ ₀ = Φ ₀ ^2P = n ₂ s ₂ · r ₂ −n ₁ · s ₁ · r ₁ Become. However, r ₁ (r ₂ ) is HO from point P ₁ (point P ₂ ).
The distance (> 0) to predetermined coordinates on the E-plane, n ₁ (n ₂ ) is the point P ₁ (point P ₂ ) of the medium on which the HOE is placed at the time of manufacture (at the time of definition).
Is the refractive index on the side where is arranged, s ₁ = HV1, and s ₂
= HV2 is a code that considers the traveling direction of light. This code indicates that the REA is a divergent light source (real point light source).
= + 1, and conversely, VIR = -1 when the light source converges (virtual point light source). As the definition of the HOE in the lens data, the refractive index n ₁ (n ₂ ) of the medium on which the HOE is placed at the time of manufacture (at the time of definition) is determined by the point P ₁ ( The refractive index on the side where the point P ₂ ) exists.

In a general case, the reference light and the object light when manufacturing the HOE are not necessarily spherical waves. The optical path difference function Φ ₀ of the HOE in this case is an additional phase term Φ ₀ represented by a polynomial.
^Poly (optical path difference function at reference wavelength λ ₀ )
(14). Φ ₀ = Φ ₀ ^2P + Φ ₀ ^Poly (14) where the polynomial is And can be generally defined as j = {(m + n) ² + m + 3n} / 2. Here, H _j is a coefficient of each term.

Further, for convenience of optical design, the optical path difference function Φ
₀ can be represented only by an additional term such as Φ ₀ = Φ ₀ ^Poly , thereby defining the HOE. For example, when the two-point light source P ₁ (point P ₂ ) is made coincident, the component Φ ₀ ^2P due to the interference of the optical path difference function Φ ₀ becomes zero. In this case, the optical path difference function is substantially composed only of the additional term (polynomial). Is equivalent to displaying. The above HOE
All descriptions are with respect to local coordinates with respect to the HOE origin.

The following is an example of configuration parameters defining the HOE. Surface number Curvature radius Interval Object surface ∞ 絞 り Aperture １００ 1002 150 -75 HOE: HV1 (s ₁ ) = REA (+1) HV2 (s ₂ ) = VIR (−1) HOR (m) = 1 HX1 = 0, HY1 = -3.40 × 10 ⁹ , HZ1 = -3.
40 × 10 ⁹ HX2 = 0, HY2 = 2.50 × 10 , HZ2 = -7.
04 × 10 HWL (λ ₀ ) = 544 H1 = −1.39 × 10 ⁻²¹ , H2 = −8.57 × 10 ⁻⁵ , H
3 = -1.50 × 10 ^-4

[0068]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the observation optical system and the image pickup optical system according to the present invention will be described below. The configuration parameters of the embodiment will be described later. In each embodiment, for example, as shown in FIG. 4, the axial principal ray 2 is moved from the center of the exit pupil 1 (or the aperture stop 14) (the center of rotation of the observer's eyeball) to the light guide plate 3, the prism 4, It is defined by a light beam reaching the center of the LCD 5 (or the imaging device 13) provided as an image display device. Then, the axial chief ray 2 is directed to the light guide plate 3
The optical axis defined by a straight line that intersects the exit pupil side surface is defined as a Z axis, and an axis orthogonal to the Z axis and within the eccentric plane of each surface constituting the prism 4 is defined as a Y axis. An axis orthogonal to the optical axis and orthogonal to the Y axis is defined as an X axis. The center of the exit pupil 1 (or the aperture stop 14) is set as the origin of this coordinate system. The direction in which the axial chief ray 2 travels from the exit pupil 1 (or the aperture stop 14) to the LCD 5 (or the image sensor 13) is defined as the positive direction of the Z axis, and the direction of the Y axis toward the LCD 5 (or the image sensor 13). Y-axis positive direction, Y
The axis, the Z axis, and the direction of the X axis forming the right-handed system are defined as the positive direction of the X axis.

In each embodiment, the light guide plate 3 and the prism 4
Is decentered in the YZ plane, and the only symmetrical plane of each rotationally asymmetric free-form surface provided in the light guide plate 3 and the prism 4 is the YZ plane.

With respect to the eccentric surface, the amount of eccentricity (X, Y, and Z in the X-axis direction, the Y-axis direction, and the Z-axis direction) at the top of the surface from the origin of the corresponding coordinate system, and the surface X axis and Y axis of the central axis (for a free-form surface, the Z axis of the above equation (7))
Tilt angles centered on the axis and the Z axis (α, β, γ, respectively)
(°)). In this case, α and β
Is positive in the positive direction of each axis, and positive in γ means clockwise in the positive direction of the Z axis. Others
The radius of curvature of the spherical surface, the spacing between the surfaces, the refractive index of the medium, and the Abbe number are given by conventional methods.

The shape of the surface of the free-form surface used in the present invention is defined by the above equation (7), and the Z axis of the definition expression is the axis of the free-form surface.

As another definitional expression of the free-form surface, Ze
There is an rnik polynomial. The shape of this surface is defined by the following equation (15). The Z axis of the definition equation (15) 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 is measured from the Y axis. Angle of rotation.

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) (15) In the above description, the plane is symmetric in the X direction. Here, D _m (m is an integer of 2 or more) is a coefficient.

The shape of a free-form surface that is a rotationally asymmetric surface can also be defined by the following equation (16). Its definition formula (16)
Is the axis of the rotationally asymmetric surface. _{Z = Σ n Σ m C nm} X n Y nm ...... (16) However, sigma _n is the n of sigma 0 to k, sigma _m is m the sigma represents 0 to n.

Further, a plane-symmetric free-form surface (a rotationally asymmetric surface having only one symmetric surface) is expressed by an equation representing the rotationally asymmetric surface.
When the symmetry caused by the symmetry plane is determined in the X direction, the odd-order term of X is set to 0 (for example, the coefficient of the X odd-order term is set to 0), and the symmetry caused by the symmetry plane is defined. When determining the sex in the Y direction, the odd-order term of Y may be set to 0 (for example, the coefficient of the Y-odd order term may be set to 0).

The shape of the rotationally symmetric aspherical surface is defined by the following equation (19). The Z axis in the definition equation (19) is the axis of the rotationally symmetric aspherical surface. _{Z = (Y 2 / R)} / [1+ {1-P (Y 2 / R 2)} 1/2] + A 4 Y 4 + A 6 Y 6 + A 8 Y 8 + A 10 Y 10 ··· ...... (19 Here, Y is a direction perpendicular to Z, R is a paraxial radius of curvature, P is a conic coefficient, and A ₄ , A ₆ , A ₈ , and A ₁₀ are aspherical coefficients.

In the embodiment of the present invention, the surface shape is represented by a free-form surface using the above equation (7).
It goes without saying that the same operation and effect can be obtained by using the equation (16).

[0078]

First Embodiment In the first embodiment , an observation optical system will be described. As an image display element, the size is 0.47 inch type in vertical and horizontal directions.
6mm x 7.2mm LCD with center diopter of -1.0D
You are using The observation angle of view is 25.
00 °, vertical total angle of view 18.88 °, pupil diameter (PD)
Is Φ1.5mm, eye relief (ER) is 18mm
It is. FIG. 4 is a YZ sectional view including the optical axis of the observation optical system according to the first embodiment of the present invention. The observation optical system according to the first embodiment is disposed between the image plane and the pupil plane, and includes at least the prism 4 and the light guide plate 3. On the image plane side, an LCD 5 is arranged as an image display element for displaying an image observed by an observer. Further, an exit pupil 1 is formed on a pupil plane for observing an observation image displayed on the LCD 5. In the following description of the embodiments, the surface number of the optical system is basically from the exit pupil 1 to the LCD.
5 is traced (reverse ray tracing), and the order of each surface of the prism is also represented in accordance with the reverse ray tracing.
Further, a light beam traveling in an optical path connecting the exit pupil 1 and the LCD 5 via the optical system is referred to as a first light beam.

[0079] prism 4 has a first surface 4 ₁ to the fourth surface 4 _4. The light guide plate 3, respectively both surfaces of the first and second regions, a volume hologram (HOE) 6 ₁ ~6 ₄ is provided. Further, the light guide plate 3 is configured to totally reflect the light flux between the first region and the second region ten times or more. In FIG. 4, the first region constitutes an incident region, and the second region constitutes an emission region.
HOEs 6 provided on both sides of the first region of the light guide plate 3
_{Numerals 1} and 6 ₂ are formed so that the light flux incident at a predetermined wavelength is diffracted and reflected, so that the light flux has an angle exceeding the total reflection critical angle of the light guide plate 3. Further, provided on both surfaces of the second region of the light guide plate 3 HOE 6 _3, 6 ₄ are a light beam incident at an angle exceeding the total reflection critical angle of the light guide plate 3 by causing respectively diffracted and reflected, the light guide plate 3 is formed so as to emit a light beam. Prism first surface 4 ₁ through 4 of 4
Surface 4 ₄ is composed of a free-form surface as a surface for correcting the decentering aberration of the light flux emitted from the light guide plate 3.

In the observation optical system of this embodiment, LC
First light beam emitted from D5 is incident transmitted through the fourth surface 4 ₄ inside the prism 4, the third surface 4 _3, second side 4 ₂
In is reflected, through the first surface 4 _1, and is emitted from the prism 4. Then, the first light flux, compared HOE 6 ₂ provided in the first region of the light guide plate 3 enters with an incidence angle of less than the critical angle.

[0081] HOE 6 ₂ light incident at the first angle of incidence below the critical angle to is transmitted as it is HOE 6 _2,
HOE6 incident on the _1. HOE 6 ₁ is configured with an angle selectivity so as to diffract and reflect light incident with a first incident angle in the incident position, diffracts and reflects the incident light. Light diffracted reflected by HOE 6 ₁ enters the HOE 6 ₂ with the second incident angle. HOE
6 ₂ is configured at an angle selectivity so as to diffract and reflect light incident with a second incident angle in the incident position, diffracts and reflects the incident light.

[0082] HOE 6 ₂ light diffracted reflected in the light guide plate 3
With a third angle of incidence exceeding the critical angle with respect to HO
Incident on the E6 _1. HOE 6 ₁ is totally reflects the light incident with a third incident angle exceeding the critical angle in the incident position. The totally reflected light is likewise with the third incident angle exceeding the critical angle, incident on the HOE 6 _2. HOE
6 _2, totally reflects the light incident with a third incident angle exceeding the critical angle at this position. Hereafter, the totally reflected light repeats the same total reflection at the interface with the outside of the glass or plastic base surface on both sides of the light guide plate 3 and forms an image once at a predetermined position in the middle thereof. It is led to HOE 6 ₄ predetermined positions provided on the second region.

[0083] HOE 6 ₄ is constituted by an angle selectivity so as to diffract and reflect light incident with a third incident angle exceeding the critical angle at a predetermined position, diffracts and reflects the incident light . Light diffracted reflected by HOE 6 ₄ is with a fourth incident angle with respect to the light guide plate and enters the HOE 6 _3. HOE 6 ₃ is configured to have angle selectivity so as to diffract and reflect light incident with a fourth incident angle at the incident position, diffracts and reflects the incident light. H
Enters the HOE 6 ₄ with an incidence angle of the 5 below the critical angle light diffracted reflected in OE6 ₃ for the light guide plate 3, HOE 6 ₄ emitted to the light guide plate 3 is transmitted through the exit pupil 1 It is led.

In the embodiments of the present invention, the description will be made as an observation optical system. However, an image pickup device 13 is arranged in place of the LCD 5 on the image plane of the observation optical system, and a pupil plane (the position of the exit pupil 1) is provided. By arranging the brightness stop 14 for reducing the brightness of the luminous flux from the object in), it is possible to configure an imaging optical system. In that case, the first area is an emission area,
The second area is the incident area. And the aperture 14
The light beam from an object passed through the is incident on the second region of the light guide plate 3, transmitted through the HOE 6 _4, after being diffracted and reflected by the HOE 6 _3, is diffracted and reflected by the HOE 6 _4, the total reflection of the light guide plate 3 The angle exceeds the critical angle, is totally reflected 10 times or more inside the light guide plate 3, and forms an image once at a predetermined position on the way to the first area, and the HOE in the first area
After being diffracted and reflected by _61, it is diffracted and reflected by the HOE 6 _2,
Transmitted through the HOE 6 ₁ emitted from the light guide plate 3. Light guide plate 3
Light beam emitted is incident on the inside of the prism 4 through the first surface 4 ₁ of the prism 4, are reflected by the second surface 4 _2, the third surface 4 _3, passes through the fourth surface 4 ₄ Then, the prism 4 is emitted and guided to the image sensor 14.

In addition, volume holograms include R, G, B
These three layers are bonded together so that a color image can be observed. Further, as shown in FIG. 4, the light guide plate 3 is formed to have a planar shape.
Further, the optical system of the present embodiment is configured such that the exit pupil 1 and the prism 4 are located on the same surface side of the light guide plate 3.

Next, numerical data of the first embodiment will be shown. In the numerical data, “FFS” indicates a free-form surface. FIG. 5 is an aberration diagram showing image distortion of the present embodiment, and FIG. 6 is an aberration diagram showing lateral aberration. In FIG. 5, the vertical axis indicates the image height in the X direction, and the horizontal axis indicates the image height in the Y direction. FIG.
Medium, (a) is the lateral aberration of the principal ray in the Y direction where the angle of view in the X direction is zero and the angle of view in the Y direction is zero, and (b) is the angle of view in the X direction and the angle of view in the Y direction are zero. Lateral aberration of the principal ray in the X direction,
(c) is the transverse aberration in the Y direction of the principal ray passing through the maximum angle of view in the X direction and zero in the X direction, and (d) is the principal ray passing through the maximum angle of view in the X direction and zero in the Y direction. Lateral aberration in the X direction, (e) is the lateral aberration in the Y direction of the principal ray passing through the maximum angle of view in the positive X direction and maximum angle of view in the negative Y direction, and (f) is the maximum angle of view in the X positive direction and the maximum angle of view in the negative Y direction (G) is the maximum angle of view in the positive X direction and the lateral aberration in the Y direction of the chief ray passing through zero in the Y direction,
(h) is the lateral aberration in the X direction of the principal ray whose X-direction maximum field angle and Y-direction field angle pass zero, and (i) is the principal ray passing through the X-positive maximum field angle and Y positive direction maximum field angle. Lateral aberration in the Y direction, (j) X direction lateral aberration of the principal ray passing through the X positive direction maximum field angle, Y positive direction maximum field angle, (k) X direction field angle is zero, Y positive direction maximum field angle (L) shows the lateral aberration in the X direction of the principal ray passing through the angle in the Y direction, and (1) showing the principal angle passing through the maximum field angle in the positive Y direction in the X direction.

Numerical Data 1 Pupil diameter: φ1.5 mm Horizontal total angle of view: 25.00 degrees Vertical front angle of view: 18.88 degrees Wavelength: 525 nm ER: 18 mm Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number HOE surface Object Surface ∞ -1000.00 1 Aperture surface 0.00 Eccentricity (1) 2 ∞ 0.00 Eccentricity (1) 3 ∞ 0.00 Eccentricity (2) 1.5163 64.1 4 ∞ 0.00 Eccentricity (3) 1.5163 64.1 5 反射 Reflective surface 0.00 Eccentricity (4) 1.5163 64.1 HOE [ 1] 6 ∞ 0.00 Eccentricity (4) 1.5163 64.1 7 ∞ 0.00 Eccentricity (5) 1.5163 64.1 8 反射 Reflective surface 0.00 Eccentricity (5) 1.5163 64.1 HOE [2] 9 ∞ 0.00 Eccentricity (5) 1.5163 64.1 10 反射 Reflective surface 0.00 eccentricity (4) 1.5163 64.1 11 反射 Reflective surface 0.00 eccentricity (5) 1.5163 64.1 12 ∞ Reflective surface 0.00 eccentricity (4) 1.5163 64.1 13 反射 Reflective surface 0.00 eccentricity (5) 1.5163 64.1 14 ∞ Reflective surface 0.00 eccentricity (4) 1.5163 64.1 15反射 Reflective surface 0.00 Eccentricity (5) 1.5163 64.1 16 反射 Reflective surface 0.00 Eccentricity (4) 1.5163 64.1 17 ∞ Reflective surface 0.00 Eccentricity (5) 1.5163 64.1 18 ∞ Reflective surface 0.00 Eccentricity (4) 1.5163 64.1 19 Reflective surface 0.00 Eccentricity (5) 1.5163 64.1 20 反射 Reflective surface 0.00 Eccentricity (4) 1.5163 64.1 21 ∞ Reflective surface 0.00 Eccentricity (5) 1.5163 64.1 22 反射 Reflective surface 0.00 Eccentricity (4) 1.5163 64.1 23 ∞ Reflective surface 0.00 Eccentricity (5 ) 1.5163 64.1 24 ∞ Reflective surface 0.00 Eccentricity (4) 1.5163 64.1 25 ∞ Reflective surface 0.00 Eccentricity (5) 1.5163 64.1 26 ∞ Reflective surface 0.00 Eccentricity (4) 1.5163 64.1 27 ∞ Reflective surface 0.00 Eccentricity (5) 1.5163 64.1 28 反射 Reflection Surface 0.00 Eccentric (4) 1.5163 64.1 29 ∞ Reflective surface 0.00 Eccentric (5) 1.5163 64.1 30 ∞ Reflective surface 0.00 Eccentric (4) 1.5163 64.1 31 反射 Reflective surface 0.00 Eccentric (5) 1.5163 64.1 32 ∞ Reflective surface 0.00 Eccentric (4) 1.5163 64.1 33 反射 Reflective surface 0.00 Eccentricity (5) 1.5163 64.1 34 ∞ Reflective surface 0.00 Eccentricity (4) 1.5163 64.1 35 ∞ Reflective surface 0.00 Eccentricity (5) 1.5163 64.1 36 ∞ Reflective surface 0.00 Eccentricity (4) 1.5163 64.1 37 反射 Reflective surface 0.00 Eccentricity (5) 1.5163 64.1 38 ∞ Reflective surface 0.00 Eccentricity (4) 1.5163 64.1 39 ∞ Reflective surface 0.00 Eccentricity (5) 1.5163 64.1 40 反射 Reflective surface 0.00 Eccentricity (4) 1.5163 64.1 41 ∞ Reflective surface 0.00 Eccentricity (5) 1.516 3 64.1 42 ∞ Reflective surface 0.00 Eccentricity (4) 1.5163 64.1 43 反射 Reflective surface 0.00 Eccentricity (5) 1.5163 64.1 44 ∞ Reflective surface 0.00 Eccentricity (4) 1.5163 64.1 45 ∞ Reflective surface 0.00 Eccentricity (5) 1.5163 64.1 46 反射 Reflective surface 0.00 Eccentricity (4) 1.5163 64.1 47 ∞ Reflective surface 0.00 Eccentricity (5) 1.5163 64.1 48 ∞ Reflective surface 0.00 Eccentricity (4) 1.5163 64.1 49 反射 Reflective surface 0.00 Eccentricity (5) 1.5163 64.1 HOE [3] 50 ∞ 0.00 Eccentricity (5 ) 1.5163 64.1 51 ∞ Reflective surface 0.00 Eccentricity (4) 1.5163 64.1 HOE [4] 52 ∞ 0.00 Eccentricity (4) 1.5163 64.1 53 ∞ 0.00 Eccentricity (5) 54 ∞ 0.00 Eccentricity (6) 55 ∞ 0.00 Eccentricity (6) 56 FFS [1] 0.00 Eccentricity (7) 1.5254 56.2 57 FFS [2] Reflective surface 0.00 Eccentricity (8) 1.5254 56.2 58 FFS [3] Reflective surface 0.00 Eccentricity (9) 1.5254 56.2 59 FFS [4] 0.00 Eccentricity (10) Image plane ∞ 0.00 Eccentricity (11)

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 = 0.00 Z = 18.00 α = 0.00 β = 0.00 γ = 0.00 Eccentricity [3 ] X = 0.00 Y = 0.00 Z = 19.00 α = 0.00 β = 0.00 γ = 0.00 Eccentricity [4] X = 0.00 Y = 0.00 Z = 19.00 α = 0.00 β = 0.00 γ = 0.00 Eccentricity [5] X = 0.00 Y = 0.00 Z = 18.00 α = 0.00 β = 0.00 γ = 0.00 Eccentricity [6] X = 0.00 Y = 40.77 Z = 15.00 α = 0.00 β = 0.00 γ = 0.00 Eccentricity [7] X = 0.00 Y = 40.77 Z = 14.50 α = 0.00 β = 0.00 γ = 0.00 Eccentricity [8] X = 0.00 Y = 40.56 Z = -3.51 α = -22.23 β = 0.00 γ = 0.00 Eccentricity [9] X = 0.00 Y = 30.83 Z = 6.19 α = -67.75 β = 0.00 γ = 0.00 Eccentricity [10] X = 0.00 Y = 50.78 Z = 6.33 α = -90.40 β = 0.00 γ = 0.00 Eccentricity [11] X = 0.00 Y = 53.78 Z = 6.33 α = -90.40 β = 0.00 γ = 0.00

HOE [1] HV1 = REA HV2 = REA HOR = 1 HX1 = 0.0 HY1 = 0.0 HZ1 = 0.0 HX2 = 0.0 HY2 = 0.0 HZ2 = 0.0 HWL = 525.00 H2 = 5.8145 × 10 ⁻¹ H3 = −2.0659 × 10 ^-2 H5 = -2.1538 x 10 ^-2 H7 = -7.77619 x 10 ^-3 H9 = 1.5407 x 10 ^-3 H10 = 2.5714 x 10 ^-4 H12 = -3.3393 x 10 ^-4 H14 = 1.6631 x 10 ^-5 H16 =- 2.7007 × 10 ^-5 H18 = 3.7914 × 10 ^-5 H20 = -1.2359 × 10 ^-5 HOE [2] HV1 = REA HV2 = REA HOR = 1 HX1 = 0.0 HY1 = 0.0 HX2 = 0.0 HY2 = 0.0 HZ2 = 0.0 HWL = 525.0 H2 = 4.9466 × 10 ^-1 H3 = 2.2801 × 10 ^-3 H5 = -1.1129 × 10 ^-3 H7 = 7.7762 × 10 ^-3 H9 = -1.5459 × 10 ^-3 H10 = -1.8260 × 10 ^-4 H12 = 4.6538 × 10 ^-4 H14 = -4.7170 x 10 ^-5 H16 = 1.9281 x 10 ^-5 H18 = -3.3546 x 10 ^-5 H20 = 1.5050 x 10 ^-5 HOE [3] HV1 = REA HV2 = REA HOR = 1 HX1 = 0.0 HY1 = 0.0 HZ1 0.0 HX2 = 0.0 HY2 = 0.0 HZ2 = 0.0 HWL = 525.0 H2 = -4.4001 × 10 -1 H3 = -1.6801 × 10 -2 H5 = -1.3627 × 10 -3 H7 = -5.1509 × 10 -4 H9 = 8.7899 × 10 ^-6 H10 = 1.8788 × 10 ^-4 H12 = 4.1180 × 10 ^-6 H14 = 1.6891 × 10 ^-7 H16 = 1.4042 × 10 ^-6 H18 = -1.3723 × 10 ^-7 H20 = -2.2827 × 10 ^-9 HOE [4] HV1 = REA HV2 = REA HOR = 1 HX1 = 0.0 HY1 = 0.0 HZ1 = 0.0 HX2 = 0.0 HY2 = 0.0 HZ2 = 0.0 HWL = 525.0 H2 = -5.2805 × 10 ^-1 H3 = 1.4959 × 10 ^-3 H5 = -1.0434 × 10 ^-3 H7 = 2.6027 x 10 ^-5 H9 = 8.2193 x 10 ^-6 H10 = -1.4081 x 10 ^-4 H12 = 3.9954 x 10 ^-6 H14 = 1.4860 x 10 ^-7 H16 = -2.66769 x 10 ^-6 H18 = 1.6153 × 10 ^-7 H20 = -4.8026 × 10 ^-9

FFS [1] C4 = -1.7627 × 10 ^-2 C6 = -3.2244 × 10 ^-2 C8 = -1.1610 × 10 ^-4 C10 = 2.4210 × 10 ^-4 C11 = 5.6144 × 10 ^-5 C13 = -2.6065 × 10 ^-5 C15 = -4.7726 x 10 ^-6 FFS [2] C4 = 7.3637 x 10 ^-3 C6 = 6.0065 x 10 ^-3 C8 = -1.3346 x 10 ^-4 C10 = -2.2866 x 10 ^-5 C11 = -3.5298 x 10 ^-6 C13 = 4.6769 × 10 ^-6 C15 = -9.8837 × 10 ^-7 FFS [3] C4 = -9.7613 × 10 ^-3 C6 = 1.6680 × 10 ^-2 C8 = -9.2368 × 10 ^-6 C10 = 2.1238 × 10 ^-3 C11 = -6.5985 × 10 ^-4 C13 = 3.0115 × 10 ^-5 C15 = 2.9208 × 10 ^-4 FFS [4] C4 = -2.0292 × 10 ^-2 C6 = -7.4393 × 10 ^-4 C8 = -6.7090 × 10 ^-4 C10 = -7.6222 × 10 ^-4 C11 = 1.6262 × 10 ^-3 C13 = 1.5184 × 10 ^-4 C15 = 1.9271 × 10 ^-3

[0091] Figure 7 shows the optical system of the second embodiment the second embodiment. FIG. 7 is a YZ sectional view including the optical axis of the observation optical system according to the second example.
In the optical system of the present embodiment, the light guide plate 3 is formed in a curved shape along the length direction. Also, the prism 4 has a second surface 4 ₂
When the surface shape of the third surface 4 ₃ to the planar shape, the surface shape of the first surface 4 ₁ and the fourth surface 4 ₄ are formed on the free-form surface. Other basic configurations are almost the same as those of the first embodiment.

[0092] The third embodiment of the optical system of the third embodiment the present invention shown in FIG. FIG. 8 is a YZ sectional view including the optical axis of the observation optical system according to the third example. The optical system of the present embodiment is configured such that the exit pupil 1 and the prism 4 are located with the light guide plate 3 therebetween. The prism 4 has a first surface 4 ₁ to the third surface 4 _3,
Face the first surface 4 ₁ has both a transmitting surface and the reflective surface, the second surface 4 ₂ reflective surface, the third surface 4 ₃ is configured as a transmitting surface.

[0093] Then, in this embodiment, the first light beam emitted from the LCD5 is incident on the inside of the prism 4 passes through the third surface 4 _3, reflected by the first surface 4 _1, the second surface 4 ₂ It is, through the first surface 4 _1, and is emitted from the prism 4. After that, the first light flux is applied to the H provided on the first region of the light guide plate 3.
To OE6 ₁ incident with an incidence angle of less than the critical angle.

[0094] HOE 6 ₁ light incident at the first angle of incidence below the critical angle to is directly transmitted through the HOE 6 _1,
Incident on the HOE6 _2. HOE 6 ₂ is configured at an angle selectivity so as to diffract and reflect light incident with a first incident angle in the incident position, diffracts and reflects the incident light. HOE 6 has light diffracted reflected by ₂ enters the HOE 6 ₁ with the second incident angle. HOE
6 ₁ is constituted by an angle selectivity so as to diffract and reflect light incident with a second incident angle in the incident position, diffracts and reflects the incident light.

[0095] HOE 6 ₁ light diffracted reflected in the light guide plate 3
At a third incident angle exceeding the critical angle with respect to the substrate surface made of glass or plastic. Less than,
Repeating total reflection similar at the interface between the external sides of the base surface of the light guide plate 3, and, to the middle of once imaged in a predetermined position of the HOE 6 ₄ provided in the second region at a predetermined position guide I will Other functions and effects are almost the same as those of the first embodiment.

[0096] A fourth embodiment of the optical system of the fourth embodiment the present invention in FIG. FIG. 9 is a YZ sectional view including the optical axis of the observation optical system according to the fourth example. In the optical system of the present embodiment, the HOEs 6 ₁ ′ and 6 ₂ ′ are integrally formed from the incident area to the emission area on each side of the light guide plate 3, and the HOEs 6 ₁ ′ and 6 ₂ ′ are formed from a predetermined position of the incidence area to the emission area. In the region up to the predetermined position, the light flux is configured to be totally reflected 10 times or more inside the light guide plate at an angle exceeding the critical angle for total reflection. Also,
In this embodiment, the HOE 6 ′ ₂ has an angle selectivity such that the light incident at the first incident angle is diffracted and transmitted at the incident position of the incident light from the prism 4, and the incident light is diffracted and transmitted. HOE 6 'at the second angle of incidence
₁ is configured to be incident.

The image display element 5 is constituted by a reflection type LCD. An illumination light source 7 is located near the prism 4.
Is provided. The prism 4 has two prisms 8,
9 are joined together with a half mirror 10 interposed therebetween, and the illumination light from the illumination light source 7 is reflected by the half mirror 10 to irradiate the reflective LCD 5, and the light beam reflected by the reflective LCD 5 is reflected by the half mirror 10. 10 and is guided to the incident area of the light guide plate 3. A light-blocking member 11 is provided on the pupil side surface of the prism 9 to prevent illumination light from the illumination light source 7 transmitted through the half mirror 10 from entering the observer's pupil and obstructing the observation. . At least one of the first surface 4 ₁ to the third surface 4 ₃ of the prism 4 is formed in the free-form surface. The other configurations, functions and effects are almost the same as those of the first embodiment.

Further, the prism used in the optical system of the present invention is not limited to the type of the embodiment described above, and a prism as shown in FIGS. 10 to 20 may be used.

In the case of FIG. 10, the prism P is
2, a second surface 33 and a third surface 34, and the first surface 32
Are the exit surfaces, the second surface 33 is the reflection surface, and the third surface 3
Numerals 4 are each configured as an incident surface. In the prism P, the light emitted from the LCD 36 is refracted on the third surface 34 and enters the prism, reflected on the second surface 33, refracted on the first surface 32 and emitted out of the prism, and exits the pupil. It is configured to form an image on the retina of the observer's eyeball (not shown) at the position 31.

In the case of FIG. 11, the prism P is
2, a second surface 33 and a third surface 34, and the first surface 32
Is a surface having both the first reflection surface and the emission surface,
The surface 33 is configured as a surface having both the third reflection surface and the incident surface, and the third surface 34 is configured as a second reflection surface. Then, the light emitted from the LCD 36 is refracted by the second surface 33 and enters the prism, and the first surface 3
After being reflected by the second surface 33, reflected by the third surface 34, reflected by the second surface 33, refracted by the first surface 32, and emitted out of the prism, the eyeball of the observer (not shown) at the position of the exit pupil 31. It is configured to form an image on the retina.

In the case of FIG. 12, the prism P is
2, a third surface 34, a third surface 34, and a fourth surface 35. The first surface 32 is an emission surface, the second surface 33 is a third reflection surface, and the third surface 34 is incident. The fourth surface 35 is configured as a first reflecting surface as a surface having both a surface and a second reflecting surface. The prism P is connected to the LCD 36
Is refracted on the third surface 34, enters the prism, is reflected on the fourth surface 35, is reflected on the third surface 34,
The light is reflected by the second surface 33, refracted by the first surface 32, exits outside the prism, and forms an image on the retina of an observer's eye (not shown) located at the exit pupil 31.

In the case of FIG. 13, the prism P is
2, a second surface 33, a third surface 34, and a fourth surface 35, wherein the first surface 32 is an emission surface, and the second surface 33 is at a different position on the same surface. The third surface 34 is a second reflection surface, and the fourth surface 3 is a third reflection surface.
5 are each configured as an incident surface. Then, after the light emitted from the LCD 36 is refracted by the fourth surface 35 and enters the prism, the light is reflected by the first reflection surface provided on the second surface 33, and is reflected by the third surface 34. The light is reflected by the third reflection surface provided on the second surface 33, refracted by the first surface 32, and emitted outside the prism, so that an image is formed on the retina of an observer's eye (not shown) at the position of the exit pupil 31. Is configured.

In the case of FIG. 14, the prism P is
2, a second surface 33, a third surface 34, and a fourth surface 35, the first surface 32 serving as an exit surface, and the second surface 33 serving as both an entrance surface and a second reflective surface. The third surface 34 is configured as a third reflective surface, and the fourth surface 35 is configured as a first reflective surface, as surfaces provided at different positions on the same surface with the fourth reflective surface. The prism P is connected to the LCD 36
Is refracted on the incident surface provided on the second surface 33, enters the prism, is reflected on the fourth surface 35, is reflected on the second reflecting surface provided on the second surface 33, and is reflected on the third surface. After being reflected at 34, the light is reflected at a fourth reflecting surface provided on the second surface 33, refracted at the first surface 32, and exits outside the prism. It is configured to form an image on it.

In the case of FIG. 15, the prism P is
2, a second surface 33 and a third surface 34, and the first surface 32
Is a surface provided with a first reflecting surface and a surface having both a third reflecting surface and an exit surface at different positions on the same surface.
The surface 33 is configured as a fourth reflective surface, and the third surface 34 is configured as a surface having both an incident surface and a second reflective surface. Then, after the light emitted from the LCD 36 is refracted by the incident surface provided on the third surface 34 and enters the prism, and reflected by the first reflecting surface provided on the first surface 32,
The first surface 32 is reflected by the second reflection surface provided on the third surface 34.
After being reflected on the third reflection surface provided on the first surface 32 and reflected on the second surface 33, the light is refracted on the exit surface provided on the first surface 32 and exits outside the prism. It is configured to form an image on the retina of the eyeball.

In the case of FIG. 16, the prism P is
2, a second surface 33 and a third surface 34, and the first surface 32
The second surface 33 is a fifth surface in which a surface having both an incident surface and a second reflection surface and a surface having both a fourth reflection surface and an emission surface are provided at different positions on the same surface. The third surface 34 is configured as a surface having both the first reflection surface and the third reflection surface. Then, after the light emitted from the LCD 36 is refracted by the incident surface provided on the first surface 32 and enters the prism, and is reflected by the first reflecting surface provided on the third surface 34, the prism P After reflecting on the second reflecting surface provided on the third surface 34 and reflecting on the third reflecting surface provided on the third surface 34, reflecting on the fourth reflecting surface provided on the first surface 32 and reflecting on the second surface 33 The light is refracted by the exit surface provided on the first surface 32, exits the prism, and forms an image on the retina of an observer's eye (not shown) located at the exit pupil 31.

In the case of FIG. 17, the prism P is the first surface 32.
, A second surface 33, a third surface 34, and a fourth surface 35,
The first surface 32 is a surface having both the second reflection surface and the emission surface, the second surface 33 is a third reflection surface, the third surface 34 is a first reflection surface, and the fourth surface 35 is incident. Each is configured as a surface. Then, after the light emitted from the LCD 36 is refracted on the fourth surface 35 and enters the prism and reflected on the third surface 34, the light emitted from the LCD 36 is reflected by the second surface 35 provided on the first surface 32.
After being reflected by the reflection surface of the first surface and reflected by the second surface 33, the light is refracted by the exit surface provided on the first surface and exits outside the prism, and the exit pupil 3
It is configured to form an image on the retina of the eyeball of an observer (not shown) at the position 1.

In the case of FIG. 18, the prism P includes a first prism P1 and a second prism P2. The first prism P1 includes a first surface 32, a second surface 33, and a third surface 3.
4 and a fourth surface 35, the first surface 32 is a surface having both the second reflection surface and the exit surface of the first prism P1, and the second surface 33 is a third reflection surface of the first prism P1. As the surfaces, the third surface 34 is configured as a first reflecting surface in the first prism P1, and the fourth surface 35 is configured as an incident surface in the first prism P1. The second prism P2 includes a first surface 41, a second surface 42, and a third surface 43.
And the first surface 41 is the first surface of the second prism P2.
The second surface 42 is configured as a second reflective surface in the second prism P2, and the third surface 43 is configured as an incident surface in the second prism P2, as a surface having both the reflective surface and the exit surface.

Then, the light emitted from the LCD 36 is refracted by the third surface 43 of the second prism P2, enters the prism, and is reflected by the first reflection surface provided on the third surface 43. After being reflected by the two surfaces 42, the light is refracted by the first surface 41 and exits outside the prism. Further, the light is refracted by the fourth surface 35 of the first prism P1, enters the prism, and is reflected by the third surface 34. After that, the light is reflected on the second reflection surface provided on the first surface 32, reflected on the second surface 33, refracted on the exit surface provided on the first surface 32, and exits outside the prism. It is configured to form an image on the retina of the eyeball of an observer (not shown).

In the case of FIG. 19, the prism P includes a first prism P1 and a second prism P2. The first prism P1 includes a first surface 32, a second surface 33, and a third surface 3.
4 and a fourth surface 35, the first surface 32 is a surface having both the second reflection surface and the exit surface of the first prism P1, and the second surface 33 is a third reflection surface of the first prism P1. As a surface, the third surface 34 is configured as a first reflecting surface in the first prism P1, and the fourth surface 35 is configured as an incident surface in the first prism P1. The second prism P2 includes a first surface 41, a second surface 42, and a third surface 43.
And a fourth surface 44, and the first surface 41 is
2, the second surface 42 is the second prism P
2, the third surface 43 is configured as a first reflective surface in the second prism P2, and the fourth surface 44 is configured as an incident surface in the second prism P2.

The light emitted from the LCD 36 is refracted by the fourth surface 44 of the second prism P2, enters the prism, is reflected by the third surface 43, is reflected by the second surface 42, The light is refracted by the first surface 41 and exits outside the prism. Further, the light is refracted by the fourth surface 35 of the first prism P1, enters the prism, is reflected by the third surface 34, and is provided on the first surface 32. After being reflected by the second reflection surface and reflected by the second surface 33, the light is refracted by the exit surface provided on the first surface 32 and exits outside the prism. It is configured to form an image on the retina.

In the case of FIG. 20, the prism P includes a first prism P1 and a second prism P2. The first prism P1 includes a first surface 32, a second surface 33, and a third surface 3.
4 and a fourth surface 35, the first surface 32 is a surface having both the second reflection surface and the exit surface of the first prism P1, and the second surface 33 is a third reflection surface of the first prism P1. As the surfaces, the third surface 34 is configured as a first reflecting surface in the first prism P1, and the fourth surface 35 is configured as an incident surface in the first prism P1. The second prism P2 includes a first surface 41, a second surface 42, and a third surface 43.
And a fourth surface 44, and the first surface 41 is
2, the second surface 42 is the second prism P
2, the third surface 43 is configured as a first reflective surface in the second prism P2, and the fourth surface 44 is configured as an incident surface in the second prism P2.

The light emitted from the LCD 36 is refracted by the fourth surface 44 of the second prism P2, enters the prism, is reflected by the third surface 43, is reflected by the second surface 42, The light is refracted by the first surface 41 and exits outside the prism. Further, the light is refracted by the fourth surface 35 of the first prism P1, enters the prism, is reflected by the third surface 34, and is provided on the first surface 32. After being reflected by the second reflection surface and reflected by the second surface 33, the light is refracted by the exit surface provided on the first surface 32 and exits outside the prism. It is configured to form an image on the retina. In addition,
19 and 20, the optical path connecting the third and fourth surfaces of the second prism P2 and the optical path connecting the first and second surfaces do not intersect in FIG. In FIG. 20, the configuration is different in that they intersect.

Next, the above-described observation optical system and imaging optical system according to the present invention include an observation device for observing an object image through an eyepiece, and an imaging device such as a CCD or a silver halide film which forms an object image and converts the image. It can be used as a photographing device that performs photographing by receiving light. Specifically, a microscope, a head-mounted image display device, an endoscope, a projector, a silver halide camera, a digital camera, a VTR camera, and an information processing device to which an observation optical system and an imaging optical system are added,
There are mobile phones. The embodiment will be exemplified below.

As an example, FIG. 21 shows a state in which a head-mounted image display device for binocular mounting is mounted on the head of an observer, and FIG. 22 (a) is a sectional view thereof. In this configuration, the observation optical system according to the present invention is used as an eyepiece optical system as shown in FIG. 22 (a), and a pair consisting of the eyepiece optical system 100 and the image display element 5 is prepared as a pair of left and right eyes. A portable image display device 102 such as a stationary or head-mounted image display device that can be observed with both eyes by being supported by a width distance is provided.

That is, in the image display device main body 102,
The observation optical system as described above is used as the eyepiece optical system 100, and the eyepiece optical system 100 is provided as a pair of left and right, and the image display element 5 composed of a liquid crystal display element is arranged on the image plane corresponding to them. Then, the image display device main body 102
As shown in FIG. 21, a temporal frame 103 is provided continuously to the left and right as shown in FIG.
02 can be held in front of the observer's eyes. In FIG. 22A, the observation optical system and the spectacle lens 15 are shown.
Are integrated into the main body of the image display device 102, but the image display device 102 may be configured without the lens 15 for glasses.

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
A playback device 106 such as a portable video cassette is connected to a display device main body 102 having a video playback device 105 via a video / audio transmission code 105.
06 is held at an arbitrary position such as a belt position as shown in the figure, so that video and audio can be enjoyed.
The reference numeral 107 in FIG. The image display device main body 10
2, electronic components such as a video processing circuit and an audio processing circuit are incorporated.

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.

As shown in FIG. 22B, the image display device main body 102 is constructed without incorporating the spectacle lens 15, and the supporting member 103 ′ connected to the image display device main body 102 is The frame 17 may be configured to be detachable. In this case, the speaker 104 in FIG. 22A may be attached to the support member 103 '. Further, as shown in FIG. 22C, the eyepiece optical system 100 and the image display element 5 are covered with the dustproof member 18 for each of the left and right eyes, and
May be connected to the frame 12 of the glasses 16.

Further, the observation 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. 23 shows a state where the camera is configured to be attached to one eye (in this case, attached to the left eye). In FIG. 23, reference numeral 111 denotes a light guide member configured by attaching holographic elements to both surfaces of a light guide unit made of glass or plastic, which is shown in the embodiment, and the light guide member 111 includes: A support member (not shown) provided at a lower portion of the display device main body 114 serves as a viewer 112.
Of the observer 112 in front of the left eye by being fixed via the ear 113 and the back of the head. In addition, as a configuration of a support member not shown, for example, a configuration described in JP-A-10-257581 can be used.

That is, the image display device according to the present embodiment is
In the case of the type supported only by the left ear of No. 12, the supporting member provided at the lower portion of the display device main body 114 is disclosed in
The "supporting portion, auxiliary supporting portion" described in Japanese Patent No. 257581 is configured to be curved from the upper base portion to the lower base portion of the ear shell of the left ear portion 113 of the observer 112. In this case, the earphone unit 115 which is a speaker
May be configured as a monaural type having only a left-ear earphone unit to which a cord 116 for transmitting an audio signal from the display device main unit 114 is connected, or in addition to the left-ear earphone unit, An earphone unit for the right ear connected to a cord (not shown) extending from 114 is attached to form a stereo type.

Further, the image display device of this embodiment is used for the observer 1
In the case of the type supported by the left and right ears of the display device 12, the support member provided at the lower portion of the display device main body 114 is disclosed in
With the "headband" described in US Pat.
In addition to providing “supporting parts, auxiliary supporting parts” that are formed by bending from the upper base part to the lower base part of the ear shell of the ear part on the left and right, adjust the “hook body” or the length By adding the configuration, it is possible to configure so that the size of the head and the position of the ear can be adapted to the alignment of the left and right ears of an observer different from each other. In this case, the cords respectively connected to the left and right earphone parts of the stereo type are connected to the “headband” or embedded inside the “headband”, and only the cord near the earphone part is exposed to the outside. It is desirable to configure as follows.

Further, the display device main unit 114 has a built-in CPU circuit and the like for enabling Internet connection and TV signal reception, and is provided with an antenna 119 for transmitting and receiving those signals.

Further, a cable 117 for transmitting video / audio signals and the like from outside extends from the display device main body 114 to the outside and is connected to the video reproducing device 118. In the figure, reference numeral 118a denotes a switch or a volume adjustment unit of the video playback device 118. Also, the cable 11
7 may be configured as a jack connectable to an existing video deck or the like. Further, in that case, the display device main unit 114 is used as a low-cost type device.
Omit the CPU circuit etc. and the antenna 119 that enable the Internet connection and TV signal reception built into the TV, and use this jack to connect to a TV radio reception tuner for TV viewing or to connect to a computer. You may be comprised so that the image of computer graphics, the image | video etc. from the internet may be received.

The display device main body 114 and the light guide member 1
An image forming unit 120 having a built-in image display element such as an LCD and a prism member, and a frame 121 that can be adjusted in position according to the size of the face of the observer are provided between the image forming device and the image forming device. The frame unit 121 has a built-in code for electrically connecting a CPU circuit built in the display device main unit 114 to an image display element such as an LCD. Further, the frame itself may be formed of an elastic body so that the position of the frame unit 121 can be adjusted, or the joint between the frame unit 121 and the display device main unit 114 may be formed of gears. 121 is the display device main body 11
4 may be made expandable and contractible.

FIGS. 24 to 26 are conceptual diagrams of a configuration in which the main components of the imaging optical system according to the present invention are incorporated in the objective optical system of the finder section of the electronic camera. 24 is a front perspective view showing the appearance of the electronic camera 40, FIG. 25 is a rear perspective view of the same, and FIG. 26 is a sectional view showing the configuration of the electronic camera 40.

In this example, the electronic camera 40 includes a photographing optical system 41 having a photographing optical path 42, a finder optical system 43 having a finder optical path 44, and a shutter button 4.
5, including a flash 46, a liquid crystal display monitor 47, etc.
When the shutter button 45 disposed on the upper part of the camera 40 is pressed, the photographing is performed through the photographing objective optical system 48 in conjunction therewith. An object image formed by the photographing objective optical system 48 is formed on the imaging surface 50 of the CCD 49 via a filter 51 such as a low-pass filter or an infrared cut filter.

The object image received by the CCD 49 is displayed as an electronic image on the liquid crystal display monitor 47 provided on the back of the camera via the processing means 52. In addition, a recording element 61 is disposed in the processing means 52, and can record a captured electronic image. Note that this recording element 6
1 may be provided separately from the processing means 52, or may be configured to perform recording and writing electronically using a floppy (registered trademark) disk or the like. Further, a silver halide camera in which a silver halide film is arranged in place of the CCD 49 may be configured.

Further, on the optical path 44 for the finder,
A finder objective optical system 53 is provided, and the finder objective optical system 53 includes a cover lens 54.
A positive lens group 57 whose position can be adjusted in the optical axis direction for focusing, a brightness stop 14, a light guide plate 3, and a prism 4 as shown in the embodiment of FIG. Also,
The cover lens 54 used as a cover member is
This is a lens group having negative power, and has an increased angle of view. The object image formed on the image plane 90 by the finder objective optical system 53 is formed on a field frame of a Porro prism 55 which is an image erecting member.

[0129] Incidentally, the field frame is separated between the first reflecting surface 56 ₁ and the second reflecting surface 56 ₂ of the Porro prism 55 is disposed therebetween. The Porro prism 55 is the first
From the reflecting surface 56 ₁ formed of the fourth reflecting surface 56 _4. An eyepiece optical system 59 for guiding the erect image to the observer's eyeball E is disposed behind the Porro prism 55.

In the camera 40 configured as described above, the finder objective optical system 53 can be configured with a small number of optical members, high performance and low cost can be realized, and the optical path itself of the objective optical system 53 can be bent. Therefore, the degree of freedom of arrangement inside the camera increases, which is advantageous in design.

Although the configuration of the photographing objective optical system 48 is not mentioned in the configuration of FIG. 26, the photographing objective optical system 48 is not limited to the refraction type coaxial optical system, but also includes two prisms of the present invention. Of course, it is also possible to use any type of imaging optical system consisting of 3 and 4.

FIG. 27 is a conceptual diagram showing a configuration in which the imaging optical system of the present invention is incorporated in the objective optical system 48 of the photographing section of the electronic camera 40, and the observation optical system of the present invention is incorporated in the eyepiece optical system 59 of the electronic camera 40. The figure is shown. In the case of this example, the imaging optical path 42
The photographing objective optical system 48 arranged above includes a cover member 65 made of a positive lens, and an imaging optical system made up of the light guide plate 3 and the prism 4 as shown in the third embodiment of the present invention. A filter 51 such as a low-pass filter or an infrared cut filter is disposed between the prism 4 and the CCD 49. An object image formed by the photographing objective optical system 48 is formed on an imaging surface 50 of the CCD 49. Is done.
The object image received by the CCD 49 is displayed as an electronic image on a liquid crystal display (LCD) 60 via the processing means 52. The processing means 52 includes a recording means 61 for recording an object image captured by the CCD 49 as electronic information.
Is also controlled. The image displayed on the LCD 60 is guided to the observer's eyeball E via the eyepiece optical system 59.

This eyepiece optical system 59 is used in the third embodiment of the present invention.
A light guide plate 3 having the same form as the observation optical system shown in FIG.
Prism 4 and cover lens 9 arranged on the exit pupil side
It consists of 1. A backlight 92 for illuminating the LCD 60 is provided behind the LCD 60. The objective optical system for photographing 48 may include another lens (a positive lens or a negative lens) as a component on the object side or the image side of the light guide plate 3 and the prism 4.

In the camera 40 thus configured, the photographing objective optical system 48 and the eyepiece optical system 59 can be composed of a small number of optical members, and high performance and low cost can be realized. The thickness in the direction perpendicular to the arrangement plane can be reduced.

In this embodiment, a positive lens is disposed as the cover member 65 of the photographing objective optical system 48, but a negative lens or a plane parallel plate may be used.

Here, without providing the cover member, the surface of the image pickup optical system according to the present invention which is disposed closest to the object can also be used as the cover member. In this example, the surface closest to the object is the incident surface of the light guide plate 3. However, since this incident surface is eccentrically arranged with respect to the optical axis, if this surface is arranged in front of the camera, the photographing center of the camera 40 is shifted from itself when viewed from the subject side. This is an illusion (similar to a general camera, it is usual to sense that the image is taken in the vertical direction of the incident surface), giving a sense of incongruity. Therefore, when the most object side surface of the imaging optical system is an eccentric surface as in this example, the cover member 65 (or
It is desirable to provide the cover lens 54) because it is possible to receive an image with the same feeling as an existing camera without feeling uncomfortable when viewed from the subject side. In addition, since the holographic element is provided on the incident surface of the light guide plate 3, it is preferable to provide the cover member 65 and the cover lens 91 in order to prevent a change in the diffraction peak wavelength due to invasion of moisture.

Next, FIG. 28 shows an image pickup optical system according to the present invention as an objective optical system 82 of an observation system of an electronic endoscope, and an observation optical system according to the present invention as an eyepiece optical system 87 of an observation system of an electronic endoscope. FIG. In this example, the objective optical system 82 and the eyepiece optical system 87 of the observation system use optical systems having substantially the same form as in the third embodiment. This electronic endoscope is shown in FIG.
As shown in FIG. 8A, an electronic endoscope 71, a light source device 72 for supplying illumination light, a video processor 73 for performing signal processing corresponding to the electronic endoscope 71, and an output from the video processor 73 Monitor 74 for displaying a video signal to be reproduced, a VTR deck 75 and a video disk 7 connected to the video processor 73 for recording video signals and the like.
6, a video printer 77 that prints out video signals as video, and a head-mounted image display (HMD) 78 as shown in FIG. 21, for example.
The distal end portion 80 of the insertion section 79 of the electronic endoscope 71 and the eyepiece section 81 are configured as shown in FIG.

The light beam illuminated from the light source device 72 passes through the light guide fiber bundle 88 and the illumination objective optical system 8.
9 illuminates the observation site. Then, light from this observation site is formed as an object image by the observation objective optical system 82 via the cover member 85. This object image is formed on the imaging surface of the CCD 84 via a filter 83 such as a low-pass filter or an infrared cut filter. Further, this object image is converted into a video signal by the CCD 84, and the video signal is directly displayed on the monitor 74 by the video processor 73 shown in FIG. And printed out from the video printer 77 as a video. The image is displayed on the image display element 5 (FIG. 21) of the HMD 78 and is displayed to the wearer of the HMD 78. At the same time, the video signal converted by the CCD 84 is displayed as an electronic image on the liquid crystal display element (LCD) 86 of the eyepiece section 81 via the image signal transmission means 93, and the displayed image is transmitted from the observation optical system of the present invention. Through the eyepiece optical system 87.

[0139] The endoscope thus configured can be configured with a small number of optical members, and can achieve high performance and low cost. In addition, since the objective optical system 80 is arranged in the longitudinal direction of the endoscope,
The above effect can be obtained without inhibiting the reduction in diameter.

Next, FIGS. 29 and 30 are conceptual diagrams showing a configuration in which the imaging optical system of the present invention is incorporated in a personal computer (hereinafter referred to as a personal computer) as an example of an information processing apparatus. 300 display screens 199
FIG. 30 is a front perspective view showing a state in which the personal computer 30 is opened.
FIG. 2 is a cross-sectional view of a display screen unit 199 showing a schematic configuration of a photographing optical system 303 and a monitor 302. In this embodiment, as the personal computer 300, a portable information terminal or a notebook-type or book-type personal computer that is particularly easy to carry is used.

As shown in FIGS. 29 and 30, the personal computer 30
Reference numeral 0 denotes a keyboard 301 for an operator to input information from the outside, an information processing device such as a CPU (not shown), a storage device such as a memory, a monitor 302 for displaying information to the operator, It has a photographing optical system 303 for photographing peripheral images.

Here, the photographing optical system 303 corresponds to the image pickup optical system of the present invention, and includes the prism 4 and the light guide plate 3 between the image plane and the pupil plane. On the image plane, a CCD 49 is arranged as an image pickup device for picking up an object image.
Prism 4 has a first surface 4 ₁ to the fourth surface 4 _4. The light guide plate 3 has a first region and a second region on both surfaces, respectively.
Volume hologram (HOE) 6 ₁ ~6 ₄ is provided. Further, the light guide plate 3 is configured to totally reflect the light flux between the second region and the first region ten times or more. In FIG. 30, the first region constitutes the emission region, and the second region constitutes the incident region.

The HOEs 6 ₃ and 6 ₄ provided on both sides of the second region of the light guide plate 3 diffract and reflect the light beams incident at a predetermined wavelength, respectively, so that the light beams become critical angles of total reflection of the light guide plate 3. It is formed so that it may become an angle exceeding. Also, H
The OEs 6 _{1 to} 6 ₄ are provided with a predetermined size near the right corner of the light guide plate 3 as viewed in FIG. Also,
HOEs 6 provided on both sides of the first region of the light guide plate 3
_1, 6 _2, a light beam incident at an angle exceeding the total reflection critical angle of the light guide plate 3 by causing respectively diffracted and reflected, the light beam from the light guide plate 3 is formed so as to be emitted. In the present embodiment, it provided in the second region of the light guide plate 3 HOE 6 ₄ plays a role as aperture stop squeezing the brightness of the light beam from the object, the incident surface is in the pupil plane. The first surface 4 ₁ to the fourth surface 4 ₄ of the prism 4 is formed by a free curved as a surface for correcting the decentering aberration of the light flux emitted from the light guide plate 3.

[0144] Then, in this embodiment, the incident light beam from the transmitted object the HOE 6 ₄ in the second region of the light guide plate 3 is, after being diffracted and reflected by the HOE 6 _3, it is diffracted and reflected by the HOE 6 _4, the light guide plate 3 , And is totally reflected 10 times or more inside the light guide plate 3, and forms an image once at a predetermined position on the way to the first region, and the first region after being diffracted and reflected by the HOE 6 ₁ in the region is diffracted reflected by HOE 6 _2, emitted from the light guide plate 3 is transmitted through the HOE 6 _1. The luminous flux emitted from the light guide plate 3 is
After entering the interior of the prism 4 through the first surface 4 ₁ of the prism 4, the second surface 4 _2, is reflected by the third surface 4 _3, passes through the fourth surface 4 _4, emits a prism 4 In a state where infrared light has been removed through the infrared cut filter 51, the CCD 4
9 and is imaged by the CCD 49.

The monitor 302 includes a light guide plate 3 and a transmissive L disposed on the rear side (right side in FIG. 30) of the light guide plate 3.
It comprises a CD 202 and a backlight 203. An image displayed on the transmissive LCD 202 by being illuminated from the back by the backlight 203 can be viewed through the light guide plate 3 by the observer. Note that the light guide plate 3 as a component of the monitor 302 also plays a role as a cover member for preventing intrusion of moisture and dust from the outside.

[0146] The upper edge 200 of the display screen unit 199 is formed with a width that does not shield the light beam incident area of the HOE 6 ₄ of the light guide plate 3 in the imaging optical system 303. The lower edge 201 of the display screen 199 is
And the prism 4 are provided, and have such a width as to cover a lower area portion of the monitor 302 which does not reach the LCD 202.

An object image received by the CCD 49 serving as an image pickup device is input to information processing means (not shown) provided in the personal computer 300, and is converted into an electronic image by the liquid crystal panel 202.
Is displayed in a partial area or the entire area of the monitor 302 via the. 29, as an example, shows a state in which the HOE 6 ₄ statue of the operator captured via the photographing optical system 303 than the incident area of the light provided is displayed as an image 305. The image information of the operator captured through the photographing optical system 303 is transmitted using information processing means, a communication cable, a communication means such as the Internet or a telephone, and the image 305 displayed on the personal computer is transmitted.
It is also possible to display the same image on a display screen of a communication destination personal computer or mobile phone from a remote place.

Next, a telephone, as another example of the information processing apparatus,
In particular, FIGS. 31 to 34 show examples in which the imaging optical system of the present invention is incorporated in a portable telephone which is convenient to carry. FIG.
Is a front view of the mobile phone 400, FIG. 32 is a side view of FIG. 31,
FIG. 33 is a sectional view showing the configuration of the monitor 404 and the photographing optical system 405, and FIG.
It is sectional drawing which shows a structure of.

As shown in FIG. 31, the portable telephone 400
A microphone unit 401 for inputting the voice of the operator as information, a speaker unit 402 for outputting the voice of the other party, an input dial 403 for the operator to input information, and a photographed image and telephone number of the other party Monitor 4 that displays information such as
04, an imaging optical system 405, an observation optical system 406, an antenna 412 for transmitting and receiving communication radio waves, and processing such as a CPU for performing processing such as data conversion of image information and character information, communication control, and control of input signals. As shown in FIG. 33, the optical system includes a prism 4 and a light guide plate 3 between an image plane and a pupil plane. On the image plane, a CCD 49 is arranged as an image pickup device for picking up an object image.
Prism 4 has a first surface 4 ₁ to the fourth surface 4 _4. The light guide plate 3 has a first region and a second region on both surfaces, respectively.
Volume hologram (HOE) 6 ₁ ~6 ₄ is provided. Further, the light guide plate 3 is configured to totally reflect the light flux between the second region and the first region ten times or more. In FIG. 33, the first region constitutes the emission region, and the second region constitutes the incident region.

The HOEs 6 ₃ and 6 ₄ provided on both sides of the second region of the light guide plate 3 diffract and reflect the light beams incident at a predetermined wavelength, respectively. It is formed so that it may become an angle exceeding. Also, H
The OEs 6 _{1 to} 6 ₄ are provided at predetermined positions at positions indicated by reference numerals 408 and 409 in the vicinity of the right corner in FIG. 31 of the light guide plate 3. The HOEs 6 ₁ , 6 ₂ provided on both sides of the first region of the light guide plate 3 diffract and reflect light beams incident at angles exceeding the total reflection critical angle of the light guide plate 3, respectively. 3 is formed so as to emit a light beam. Note that in the photographing optical system 405 of the present embodiment, provided in the second region of the light guide plate 3 HOE 6 ₄ plays a role as aperture stop squeezing the brightness of the light beam from the object, the incident surface pupil plane It has become. The first surface 4 ₁ to the fourth surface 4 ₄ of the prism 4 is formed by a free curved as a surface for correcting the decentering aberration of the light flux emitted from the light guide plate 3.

In the photographing optical system 405 of this embodiment,
In the second region of the light guide plate 3, the incident light beam from the object transmitted through the HOE 6 ₄ is, after being diffracted and reflected by the HOE 6 _3, is diffracted and reflected by the HOE 6 _4, it exceeds a total reflection critical angle of the light guide plate 3 At an angle, the light is totally reflected 10 times or more inside the light guide plate 3, forms an image once at a predetermined position on the way, and goes to the first region, and the HOE 6 in the first region.
After being diffracted and reflected at _1, it is diffracted and reflected by the HOE 6 _2, H
Through the OE6 ₁ emitted from the light guide plate 3. Light beam emitted from the light guide plate 3, after entering the interior of the prism 4 through the first surface 4 ₁ of the prism 4, the second surface 4 _2, the third surface 4 ₃
In is reflected, passes through the fourth surface 4 _4, emits a prism 4, through the infrared cut filter 51 is guided to the CCD 49 in a state where infrared light is removed, it is captured by the CCD 49.

The monitor 404 includes a light guide plate 3 and a transmissive L disposed on the rear side (right side in FIG. 33) of the light guide plate 3.
It comprises a CD 202 and a backlight 203. An image displayed on the transmissive LCD 202 by being illuminated from the back by the backlight 203 can be viewed through the light guide plate 3 by the observer as a real image. The monitor 40
The light guide plate 3 as a component of 4 also plays a role as a cover member for preventing intrusion of moisture and dust from the outside.

The object image received by the CCD 49 serving as the image pickup device is input to the information processing means 206 provided in the mobile phone 400, and is converted into an electronic image by the liquid crystal panel 20.
2 is displayed in a partial area or the entire area of the monitor 404. FIG. 31 shows, as an example, a state in which an image of the operator captured by the imaging optical system 405 is displayed. The object image received by the image sensor (CCD) 49 may be input to the processing unit 206 and then displayed on the monitor of the communication partner or on both monitors. To transmit an image to a communication partner, the information processing apparatus is provided with a signal conversion processing function of converting information of an object image received by the imaging device (CCD) 49 into a transmittable signal.

As shown in FIG. 34, the observation optical system 406 of this embodiment includes a prism 4 and a light guide plate 3 between an image plane and a pupil plane. On the image plane, a small LC is used as an image display element for displaying an image observed by the observer.
D204 is provided with a backlight 205 on the back side (the lower side in FIG. 34). An exit pupil is formed on the pupil plane. Prism 4 is the first
It has a surface 4 _one to the fourth surface 4 _4. The light guide plate 3 is provided with volume holograms (HOE) 6 ′ _{1 to} 6 ′ _{4 on} both surfaces of the first region and the second region, respectively. Further, the light guide plate 3 is configured to totally reflect the light flux between the second region and the first region ten times or more. In FIG. 34, the first region constitutes an incident region, and the second region constitutes an emission region.

The HOEs 6 ′ ₁ , 6 ′ ₂ provided on both sides of the first region of the light guide plate 3 diffract and reflect light beams incident at a predetermined wavelength, respectively, so that the light beams are totally reflected by the light guide plate 3. The angle is formed so as to exceed the critical angle. Further, HOs provided on both surfaces of the second region of the light guide plate 3 are provided.
E6 ′ ₃ and 6 ′ ₄ are formed so that the light fluxes incident at angles exceeding the total reflection critical angle of the light guide plate 3 are respectively diffracted and reflected, so that the light fluxes are emitted from the light guide plate 3. Also,
The HOEs 6 ′ _{1 to} 6 ′ ₄ are provided at predetermined positions at positions indicated by reference numerals 410 and 411 near the left corner of the light guide plate 3 in FIG. First surface 4 of prism 4
₁ to the fourth surface 4 ₄ is composed of a free-form surface as a surface for correcting the decentering aberration of the light flux emitted from the light guide plate 3.

[0156] Then, the observation optical system 406 of the present embodiment, a light beam emitted from the illuminated LCD204 backlight 205 is incident on the inside of the prism 4 transmits through the fourth surface 4 _4, 3 surface 4 _3, it is reflected by the second surface 4 _2,
Through the first surface 4 _1, and is emitted from the prism 4. Thereafter, the HOE 6 ′ ₂ provided in the first region of the light guide plate 3
Incident at an angle of incidence below the critical angle
After transmitting through 6 ′ ₂ and diffracted and reflected by HOE 6 ′ ₁ , H
The light is diffracted and reflected by the OE 6 ′ ₂ and has an angle exceeding the total reflection critical angle of the light guide plate 3, is totally reflected 10 times or more inside the light guide plate 3, and forms an image once at a predetermined position in the middle thereof. To the second area, where the HOE 6 ′ ₃
In after being diffracted and reflected, it is diffracted and reflected by the HOE 6 _'4,
The light passes through the HOE 6 ′ ₃ , exits from the light guide plate 3, and is guided to an exit pupil provided on the optical path of the monitor 404 passing through the HOE 6 ′ ₄ .

At this time, the small image formed by the small LCD 204 and the backlight 205 is enlarged and projected onto the eyeball E of the observer via the light guide plate 3, and the observer forms the image on the surface of the small LCD 204. The observed image is observed as a virtual image that is enlarged and projected.

When observing the magnified and projected image, the observer must bring the eyeball E closer to the exit pupil position formed by the light guide plate 3.
In addition to not being able to see the image of the LCD 203 displayed on most of the area of the LCD 4, the light of the image displayed on the LCD 203 rather prevents the observation optical system 406 from enlarging the image displayed on the small LCD 204. May be done. Therefore, in such a case, it is desirable that the CPU (processing means) 206 controls the amount of illumination light of the backlight 203 to be reduced or turned off. Also, if you do this,
Further, an effect of increasing power consumption can be expected.

Next, FIG. 35 shows a desirable configuration when a diffractive element such as a volume hologram is provided on the light guide plate with respect to the prism constituting the optical system according to the present invention. In the figure, an eccentric prism P is a prism 4 included in the observation optical system or the imaging optical system of the present invention. Now, the surface C of the diffraction element
If the first surface of the eccentric prism P is formed as a plane-symmetric free-form surface when the first surface of the decentered prism P is formed as shown in the drawing, the symmetric surface D is at least one of the sides forming the square of the surface C of the diffraction element. To be arranged in parallel with one,
Desirable for beautiful image formation.

Further, when the surface C of the diffraction element has four interior angles of approximately 90 °, such as a square and a rectangle, the plane of symmetry D of the plane-symmetric free-form surface is the same as that of the surface C of the diffraction element. It is preferable that the planes of symmetry D are arranged in parallel to two sides that are in a parallel relationship with each other, and that the plane of symmetry D coincides with the position where the plane C of the diffraction element is symmetrical left and right or up and down. With such a configuration, it is easy to obtain the accuracy of assembling when assembling into the device, which is effective for mass production.

Further, when a plurality of or all of the first, second, third and fourth optical surfaces constituting the decentered prism P are plane-symmetric free-form surfaces, It is desirable from the viewpoint of both design and aberration performance that the plurality of surfaces or the symmetrical surfaces of all surfaces are arranged on the same surface D.
It is desirable that the relationship between the symmetry plane D and the power plane of the diffraction element be the same as described above.

As described above, the optical system of the present invention
In addition to the features described in the claims, the following features are provided.

(1) In an observation optical system including the optical system according to claim 1, an image display element for displaying an image observed by an observer is arranged on the image plane, and the observer's eyeball is arranged on the pupil plane. Is formed so that the exit pupil is located, the light flux emitted from the image display element, after passing through the prism,
The holographic element which is incident on the first region of the light guide plate, is diffracted and transmitted by the holographic element provided on the prism side of the light guide plate, and is provided on the light guide plate on the side opposite to the prism Is diffracted and reflected at an angle exceeding the total reflection critical angle of the light guide plate, and heads toward the second region of the light guide plate while being totally reflected 10 times or more inside the light guide plate, In the region, the light is diffracted and reflected by the holographic element provided on the exit pupil side of the light guide plate, and is diffracted and reflected by the holographic element provided on the light guide plate on the side opposite to the exit pupil, and the light is guided by the light guide plate. An angle that does not exceed the critical angle of total reflection of the light plate, passes through the holographic element provided on the exit pupil side of the light guide plate, exits from the light guide plate, and is guided to the exit pupil. The observation optical system, characterized in that the configuration was.

(2) In the observation optical system including the optical system according to claim 1, an image display element for displaying an image observed by an observer is arranged on the image plane, and the observer's eyeball is arranged on the pupil plane. Is formed so that the exit pupil is located, the light flux emitted from the image display element, after passing through the prism,
The holographic element which is incident on the first region of the light guide plate, is diffracted and transmitted by the holographic element provided on the prism side of the light guide plate, and is provided on the light guide plate on the side opposite to the prism Is diffracted and reflected at an angle exceeding the total reflection critical angle of the light guide plate, and heads toward the second region of the light guide plate while being totally reflected 10 times or more inside the light guide plate, In the region, the light is diffracted and reflected by the holographic element provided on the side opposite to the exit pupil of the light guide plate, is diffracted and transmitted by the holographic element provided on the exit pupil side of the light guide plate, and An observation optical system, wherein the observation optical system is configured to emit light from a light plate and to be guided to the exit pupil.

(3) In the observation optical system including the optical system according to claim 1, an image display element for displaying an image observed by an observer is arranged on the image plane, and the observer's eyeball is arranged on the pupil plane. Is formed so that the exit pupil is located, the light flux emitted from the image display element, after passing through the prism,
The light enters the first region of the light guide plate, passes through the holographic element provided on the prism side of the light guide plate, and includes the holographic element provided on the opposite side of the light guide plate from the prism. The light is diffracted and reflected, and is diffracted and reflected by the diffraction element provided on the prism side of the light guide plate to have an angle exceeding the total reflection critical angle of the light guide plate, and is totally reflected 10 times or more inside the light guide plate While being directed toward the second region of the light guide plate, and in the second region, the light is diffracted and reflected by the holographic element provided on the opposite side of the light guide plate to the exit pupil, and the light exits the light guide plate. An observation optical system, wherein the observation optical system is configured to be diffracted and transmitted by the holographic element provided on the pupil side, to be emitted from the light guide plate, and to be guided to the exit pupil.

(4) In the image pickup optical system including the optical system according to claim 1, an image pickup device for picking up an object image is arranged on the image plane, and the brightness of a light beam from the object is narrowed on the pupil plane. A brightness stop is arranged, and a light beam from an object that has passed through the brightness stop is incident on a second region of the light guide plate, and is diffracted and transmitted by the holographic element provided on the object side of the light guide plate. It is diffracted and reflected by the holographic element provided on the opposite side of the light guide plate from the object, and has an angle exceeding the total reflection critical angle of the light guide plate,
The light guide plate faces the first region while being totally reflected 10 times or more inside, and is diffracted and reflected by the holographic element provided on the prism side of the light guide plate in the first region. The holographic element provided on the side opposite to the prism is diffracted and reflected, passes through the diffraction element provided on the prism side, emits from the light guide plate, and passes through the prism to the image sensor. An imaging optical system characterized in that the imaging optical system is configured to be guided to the imaging device.

(5) In the image pickup optical system including the optical system according to claim 1, an image pickup device for picking up an object image is arranged on the image plane, and the brightness of a light beam from the object is narrowed on the pupil plane. A brightness stop is arranged, and a light beam from an object that has passed through the brightness stop enters a second area of the light guide plate and is transmitted by the holographic element provided on the object side of the light guide plate. The light guide plate is diffracted and reflected by the holographic element provided on the side opposite to the object, and the light guide plate is diffracted and reflected by the holographic element provided on the object side of the light guide plate. Becomes an angle exceeding the reflection critical angle, heads toward the first region while being totally reflected 10 times or more inside the light guide plate, and is provided on the opposite side of the light guide plate from the prism in the first region. Holography The light is diffracted and reflected by the light guide element, diffracted and transmitted by the holographic element provided on the prism side of the light guide plate, emitted from the light guide plate, and guided to the image pickup device via the prism. An imaging optical system, characterized in that:

(6) In the image pickup optical system including the optical system according to claim 1, an image pickup device for picking up an object image is arranged on the image plane, and the brightness of a light beam from the object is narrowed on the pupil plane. A brightness stop is arranged, and a light flux from an object that has passed through the brightness stop is incident on a second region of the light guide plate and passes through the holographic element provided on the object side of the light guide plate. The light guide plate is diffracted and reflected by the holographic element provided on the side opposite to the object, and the light guide plate is diffracted and reflected by the holographic element provided on the object side of the light guide plate. Becomes an angle exceeding the reflection critical angle, heads toward the first region while being totally reflected 10 times or more inside the light guide plate, and is provided on the opposite side of the light guide plate from the prism in the first region. Holography It is configured to be diffracted and reflected by the element, diffracted and transmitted by the holographic element provided on the prism side of the light guide plate, emitted from the light guide plate, and guided to the image pickup device via the prism. An imaging optical system, characterized in that:

(7) The relay optical system according to any one of (1) to (6), wherein the relay optical system is configured so that an incident light beam forms an intermediate image inside the light guide plate. Optical system.

(8) When the pupil diameter is PD and the eye relief is ER, the following conditional expression (1) is satisfied: (2), (1) to (3), and (2). The observation optical system according to any one of the above (7), wherein 0.1 ≦ PD ≦ ER × 0.9 …… (1)

(9) When the pupil diameter is PD and the eye relief is ER, the following conditional expression (2) is satisfied: (2), (1) to (3), and (2). The observation optical system according to any one of the above (7), wherein 1.0 ≦ PD ≦ ER × 0.6 …… (2)

(10) Pupil diameter is PD and eye relief is ER
Wherein the following conditional expression (3) is satisfied: the observation optics according to any one of (2), (1) to (3), and (7) subordinate to claim 2. system. 1.0 ≦ PD ≦ ER × 0.3 …… (3)

(11) When the distance from the incident position of the axial chief ray to the exit position within the light guide plate is L,
The following conditional expression (4) is satisfied:
3. The optical system according to any one of the above (1) to (10). 30.0 mm ≦ L ≦ 200.0 mm (4)

(12) Assuming that the distance from the incident position of the axial chief ray to the exit position is L in the light guide plate,
The following conditional expression (5) is satisfied:
3. The optical system according to any one of the above (1) to (10). 35.0 mm ≦ L ≦ 140.0 mm (5)

(13) Assuming that the distance from the incident position of the axial chief ray to the exit position is L in the light guide plate,
The following conditional expression (6) is satisfied:
3. The optical system according to any one of the above (1) to (10). 40.0 mm ≦ L ≦ 70.0 mm (6)

(14) The pupil plane and the prism are located on the same plane side of the light guide plate.
To 3, and the optical system according to any one of the above (1) to (13).

(15) The pupil plane and the prism are located at positions separated by the light guide plate.
3. The optical system according to any one of the above (1) to (13).
Optical system.

(16) The image display device according to (2), wherein the image display device is a transmission type image display device.
(3) The observation optical system according to any one of (7) to (15), which is dependent on claim 2.

(17) The image display device according to (2), wherein the image display device is a reflection type image display device.
(3) The observation optical system according to any one of (7) to (15), which is dependent on claim 2.

(18) An illumination light source is provided, and the prism guides illumination light from the illumination light source to the reflection-type image display element, and further, the light flux reflected by the reflection-type image display element is reflected by the prism. (17) The observation optical system according to (17), wherein the observation optical system is configured to be guided to an incident area of the light guide plate.

(19) The holographic element is provided separately in an incident area and an emission area on each side of the light guide plate.
3. The optical system according to any one of the above (1) to (18).

(20) The holographic elements are integrally formed on each side of the light guide plate from the incident area to the emission area, and are formed from a predetermined position of the incidence area to a predetermined position of the emission area. The luminous flux in the area,
At an angle exceeding the critical angle for total reflection, 1
The optical system according to any one of claims 1 to 3, wherein the optical system is configured to perform total reflection zero or more times.

(21) An image pickup device is provided on the side opposite to the exit pupil with the light guide plate interposed therebetween, and when an observer is observing an image displayed on the image display device via the light guide plate. 3. An image of an observer is transmitted through the light guide plate so as to be imaged, wherein (1) to (3),
The observation optical system according to any one of (1) to (20), which is dependent on claim 2.

(22) The optical system according to any one of (1) to (21), wherein the light guide plate is formed in a planar shape.

(23) The optical system according to any one of (1) to (21), wherein the light guide plate is formed in a curved shape.

(24) The optical system according to any one of (1) to (23), wherein said holographic element is constituted by a volume hologram.

(25) The light beam emitted from the image display element is totally reflected at least 20 times inside the light guide plate, according to the above items (1) to (3),
The observation optical system according to any one of the above (7) to (24), which is dependent on claim 2.

(26) The light beam emitted from the image display element is totally reflected at least 30 times inside the light guide plate, according to the above (1) to (3),
The observation optical system according to any one of the above (7) to (24), which is dependent on claim 2.

(27) The light beam from an object that has passed through the aperture stop is totally reflected at least 20 times inside the light guide plate.
(6) The above (7), (11) to (3) dependent on claim 3
(15) The imaging optical system according to any one of (19), (20), and (22) to (24).

(28) The light beam from an object passing through the aperture stop is totally reflected at least 30 times inside the light guide plate.
(6) The above (7), (11) to (3) dependent on claim 3
(15) The imaging optical system according to any one of (19), (20), and (22) to (24).

(29) The prism according to any one of (1) to (28), wherein the curved surface for correcting the eccentric aberration is a free-form surface. Optical system as described.

(30) Claim 2, the above (1) to (3),
A main body incorporating the observation optical system according to any one of (7) to (26) and (29) according to claim 2, and an exit pupil of the observation optical system is held at an eyeball position of an observer. A head-mounted image display device comprising a support member for supporting the main body portion on the observer's head and a speaker member for giving sound to the observer's ear.

(31) In the head mounted image display device according to the above (30), the main body comprises an observation optical system for the right eye and an observation optical system for the left eye, and the speaker member is A head-mounted image display device comprising a right-ear speaker member and a left-ear speaker member.

(32) The head-mounted image display device according to the above (30) or (31), wherein the speaker member comprises an earphone.

[0195]

As described above, according to the present invention, a small, lightweight, bright, and high-resolution observation optics suitable for use in a portable telephone, a portable information terminal, and a head-mounted virtual image observation apparatus. System and an imaging optical system can be provided.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of an optical system according to the present invention.

FIG. 2 is a principle explanatory view showing a reflection state of light incident on a light guide plate constituting the optical system according to the present invention.

FIG. 3 is a conceptual diagram for explaining a state in which an axial ray is intermediately imaged inside a light guide plate in the configuration of FIG. 1;

FIG. 4 is a YZ sectional view including the optical axis of the optical system according to the first example of the present invention.

FIG. 5 is an aberration diagram illustrating image distortion of the first example.

FIG. 6 is an aberration diagram showing a lateral aberration in the first example.

FIG. 7 is a YZ sectional view including an optical axis of an optical system according to a second example of the present invention.

FIG. 8 is a YZ sectional view including an optical axis of an optical system according to a third example of the present invention.

FIG. 9 is a YZ sectional view including an optical axis of an optical system according to a fourth example of the present invention.

FIG. 10 is a diagram showing an example of a prism applicable to the prism member of the optical system according to the present invention.

FIG. 11 is a view showing another example of a prism applicable to the prism member of the optical system of the present invention.

FIG. 12 is a diagram showing still another example of a prism applicable to the prism member of the optical system of the present invention.

FIG. 13 is a view showing still another example of a prism applicable to the prism member of the optical system according to the present invention.

FIG. 14 is a diagram showing still another example of a prism applicable to the prism member of the optical system of the present invention.

FIG. 15 is a view showing still another example of a prism applicable to the prism member of the optical system of the present invention.

FIG. 16 is a view showing still another example of a prism applicable to the prism member of the optical system according to the present invention.

FIG. 17 is a diagram showing still another example of a prism applicable to the prism member of the optical system of the present invention.

FIG. 18 is a view showing still another example of a prism applicable to the prism member of the optical system according to the present invention.

FIG. 19 is a view showing still another example of a prism applicable to the prism member of the optical system of the present invention.

FIG. 20 is a diagram showing still another example of a prism applicable to the prism member of the optical system according to the present invention.

FIG. 21 is a diagram showing a state in which a head-mounted binocular image display device using the observation optical system of the present invention is mounted on the head of an observer.

FIG. 22 is a diagram of a head-mounted binocular image display device using the observation optical system of the present invention as viewed from above, and FIG.
Is a cross-sectional view of FIG. 17, (b) is a cross-sectional view showing a modification of (a),
(c) is a sectional view showing another modification of (a).

FIG. 23 is a diagram illustrating a state in which a head-mounted image display device for one eye mounting using the observation optical system of the present invention is mounted on the head of an observer.

FIG. 24 is a front perspective view showing the appearance of an electronic camera to which the imaging optical system and the observation optical system of the present invention are applied.

FIG. 25 is a rear perspective view of the electronic camera of FIG. 24;

26 is a cross-sectional view showing one configuration of the electronic camera in FIG.

FIG. 27 is a conceptual diagram of another electronic camera to which the imaging optical system and the observation optical system of the present invention are applied.

FIG. 28 is a conceptual diagram of an electronic endoscope to which the imaging optical system and the observation optical system of the present invention are applied.

FIG. 29 is a front perspective view showing a state in which a display screen of a personal computer having an imaging optical system of the present invention built therein is opened.

30 is a cross-sectional view of a display screen part showing a schematic configuration of a photographing optical system and a monitor of the personal computer of FIG. 29.

FIG. 31 is a front view of a mobile phone incorporating the imaging optical system of the present invention.

FIG. 32 is a side view of FIG. 31.

33 is a cross-sectional view showing a configuration of a monitor 404 and a photographing optical system 405 in the mobile phone of FIG.

34 is a cross-sectional view illustrating a configuration of a monitor 404 and an observation optical system 406 in the mobile phone of FIG.

FIG. 35 shows an example in which the prism constituting the optical system according to the present invention is H-shaped.
FIG. 3 is a diagram illustrating a preferred configuration when OEs are arranged.

FIG. 36 is a principle diagram for defining a HOE in the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 exit pupil 2 axial principal ray 3 light guide plate 4 prism 4 ₁ first surface 4 ₂ second surface 4 ₃ third surface 4 ₄ fourth surface 5, 202, 204 LCD 6 ₁ , 6 ₂ , 6 ₃ , 6 ₄ , 6 ₁ ′, 6 ₂ ′ Volume hologram (HOE) 7 Light source for illumination 8, 9 Prism 10 Half mirror 11 Shielding member 13 Image sensor 14 Brightness aperture 15 Lens for eyeglasses 16 Glasses 17 Frame 18 Dustproof member 40 Camera 41 Imaging Optical system 42 Optical path for photographing 43 Optical path for finder 44 Optical path for finder 45 Shutter 46 Flash 47 Liquid crystal display monitor 48 Objective optical system for photographing 49 CCD 50 Imaging surface 51 Filter 52 Processing means 53 Objective optical system for viewfinder 54 Negative lens group 55 Polo prisms 56 ₁ to 56 ₄ first to fourth reflecting surface 57 the positive lens group 59 eyepiece 60 liquid crystal display device ( CD) 61 Recording element 65 Cover member 71 Electronic endoscope 72 Light source device 73 Video processor 74 Monitor 75 VTR deck 76 Video disk 77 Video printer 78 Head mounted image display device (HMD) 79 Insertion section 80 Tip section 81 Eyepiece Unit 82 Observation objective optical system 83 Filter 84 CCD 85 Cover member 86 Liquid crystal display device (LCD) 87 Eyepiece optical system 88 Light guide fiber bundle 89 Illumination objective optical system 90 Image forming surface 91 Cover member 92, 203, 205 Backlight 93 image signal transmission means 100 eyepiece optical system 102 image display device (main body) 103 temporal frame 104 speaker 105 video / audio transmission code 106 playback device 107 adjustment unit 108 front frame 111 light guide member 112 observer 113 ear 114 display Main body section 115 Earphone section 116 Cord 117 Cable 117a Cable tip section 118 Video playback device 118a Switch, volume adjustment section 119, 412 Antenna 120 Image forming unit section 199 Display screen section 200 Upper edge section 201 Lower edge section 206 Information processing means Reference Signs List 300 personal computer 301 keyboard 302,404 monitor 303,405 photographing optical system 305 image 400 mobile phone 401 microphone section 402 speaker section 403 input dial 406 observation optical system P decentered prism C surface of diffractive element D plane symmetrical surface of free-form surface

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 5/32 G02B 5/32 H04N 5/64 511 H04N 5/64 511A

Claims (3)

[Claims] 1. An optical system disposed between a pupil plane and an image plane, wherein the optical system includes at least a prism and a light guide plate, and the light guide plate is provided on both surfaces in an incident area and an exit area, respectively. It has a holographic element, and is configured to totally reflect the light flux 10 times or more inside the light guide plate to reach from the incident region to the emission region, and is provided on both surfaces of the incident region of the light guide plate. The holographic element is formed such that light beams incident at predetermined positions at predetermined wavelengths are respectively diffracted, and an incident angle of the light beams is an angle exceeding a total reflection critical angle of the light guide plate, and the light guide plate is formed. The holographic elements provided on both sides of the emission region diffract light beams guided from the incident region to the emission region at predetermined positions, respectively, so that the incident angle of the light beam is the light guide plate. An angle not exceeding the critical angle for total reflection is formed so that a light beam is emitted from the light guide plate, and the prism is for correcting eccentric aberration of the light beam emitted from the light guide plate to at least one surface. An optical system having a curved surface. 2. An observation optical system including the optical system according to claim 1, wherein an image display element for displaying an image observed by an observer is arranged on the image plane, and an eyeball of the observer is arranged on the pupil plane. An exit pupil is formed so as to be located, and a light beam emitted from the image display element is incident on a first region of the light guide plate after passing through the prism, and is provided on the prism side of the light guide plate. Transmitted through the holographic element, is diffracted and reflected by the holographic element provided on the side of the light guide plate opposite to the prism, is diffracted and reflected by the diffraction element provided on the prism side of the light guide plate. The light guide plate has an angle exceeding the total reflection critical angle, and travels toward the second region of the light guide plate while being totally reflected 10 times or more inside the light guide plate. Light source Diffracted and reflected by the holographic element provided on the exit pupil side, diffracted and reflected by the holographic element provided on the side opposite to the exit pupil of the light guide plate, and sets the total reflection critical angle of the light guide plate. An observing optic, wherein the angle does not exceed, and the light is transmitted through the holographic element provided on the exit pupil side of the light guide plate, is emitted from the light guide plate, and is guided to the exit pupil. system. 3. An image pickup optical system including the optical system according to claim 1, wherein an image pickup element for picking up an object image is arranged on said image plane, and said pupil plane is used to reduce the brightness of a light beam from an object. A light beam from an object that has passed through the brightness stop is incident on a second region of the light guide plate, and passes through the holographic element provided on the object side of the light guide plate; Diffracted and reflected by the holographic element provided on the opposite side to the object of the light guide plate, and diffracted and reflected by the holographic element provided on the object side of the light guide plate,
It becomes an angle exceeding the total reflection critical angle of the light guide plate, heads toward the first region while being totally reflected 10 times or more inside the light guide plate, and in the first region, on the prism side of the light guide plate. Diffracted and reflected by the provided holographic element, diffracted and reflected by the holographic element provided on the side of the light guide plate opposite to the prism, and transmitted through the diffractive element provided on the prism side. An imaging optical system configured to emit light from the light guide plate and to be guided to the imaging device via the prism.