JPH10307263A - Prism optical element and image observation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a very compact prism optical element capable of giving a clear observed image with little aberration and little distortion even at the wide angle of view. SOLUTION: A light beam emitted from a picture display element 7 is made incident on the 4th surface 6 of an ocular optical system 12, totally reflected to the side of the pupil 1 of an observer by the 3rd surface 5, reflected by the 1st surface 3 arranged just before the pupil 1, reflected to the side of the pupil 1 by the 2nd surface 4 and transmitted through the 1st surface 3 so as to be projected into the eyeball 15 of the observer with the position of the iris of the observer as an exit pupil 1. In the case of observing the picture of the external environment, the light beam from an object point in the external environment is made incident from the 3rd surface 5, transmitted through the 1st surface 3 and projected into the eyeball 15 of the observer. Assuming that the angle of the internal reflection of the optional light beam on the 3rd surface 5 is θr3 , sin<-1> (1/nd )<=θr3 <=60 deg. is satisfied. Provided that nd is the refractive index of the d-line of the medium of the optical system 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prism optical element and an image observation device, and more particularly to a head or face-mounted image display device capable of being held on the head or face of an observer.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 3-101709 discloses a conventional head or face-mounted image display apparatus. This image display device transmits a display image of an image display element as an aerial image by a relay optical system composed of a positive lens, and enlarges this aerial image by an eyepiece optical system composed of a concave reflecting mirror to enter an observer's eyeball. It is to project.

Another conventional type is disclosed in US Pat. No. 4,669,810. This apparatus forms an intermediate image from a CRT image via a relay optical system, and projects the intermediate image on an observer's eye by a combiner having a reflective holographic element and a hologram surface.

Further, another conventional image display device is disclosed in US Pat. No. 4,026,641. In this device, an image of an image display device is transmitted to a curved object surface by a transmission device, and the object surface is projected onto the air by a toric reflection surface.

Another conventional type of image display device is disclosed in US Pat. No. Re. 27,356.
This apparatus is an eyepiece optical system that projects an object plane onto an exit pupil by using a transflective concave mirror and a transflective plane mirror.

In addition, US Pat. No. 4,322,135
No. 4,969,724; European Patent No. 0,724;
Nos. 583 and 116A2 and JP-A-7-333551 are also known.

[0007]

However, in the image display device of the type that relays the image of the image display device as disclosed in Japanese Patent Application Laid-Open No. 3-101709 and US Pat. No. 4,669,810, the type of the eyepiece optical system Regardless, several lenses must be used as a relay optical system in addition to the eyepiece optical system, so the optical path length is long, the optical system becomes large, and the weight becomes heavy.

[0008] The head-mounted image display device is a human body,
In particular, since the device is worn on the head, if the amount of the device protruding from the face is large, the distance from the point supported by the head to the center of gravity of the device becomes longer, and the balance when worn becomes poor. Further, there is a possibility that the apparatus may hit an object when the apparatus is mounted, moved, rotated, or the like. That is, it is important that the head-mounted image display device is small and lightweight.
A major factor that determines the size and weight of this device is the configuration of the optical system.

However, if only a normal magnifying glass is used as the eyepiece optical system, the generated aberration is very large and there is no means for correcting it. Even if spherical aberration can be corrected to some extent by making the concave surface of the magnifying mirror aspherical, coma aberration, field curvature, etc. remain, so if the observation angle of view is increased, it cannot be a practical device. . Alternatively, when only a concave mirror is used as the eyepiece optical system, this is corrected not only by a normal optical element (lens or mirror) but also by a conductive element (fiber plate) having a surface curved in accordance with the generated field curvature. You must use the means of doing

Further, in a type such as US Pat. No. 4,026,641 in which an image of an image display device is projected onto an observer's eyeball using a toric reflecting surface, the field curvature caused by an eccentric toric reflecting surface. Is corrected by curving the object surface itself, it is difficult to use a so-called flat display such as an LCD (liquid crystal display element) as an image display element.

On the other hand, in a coaxial eyepiece optical system for projecting an object plane to an observer's pupil by using a semi-transmissive concave mirror and a semi-transmissive plane mirror as disclosed in US Pat. No. Re. 27,356,
Since two semi-transmissive surfaces are used, the brightness of the image is reduced to 1/16 even with the theoretical value. Further, since the curvature of field generated by the semi-transmissive concave mirror is corrected by bending the object plane itself, it is difficult to use a flat display such as an LCD (liquid crystal display element) as an image display element as described above. is there.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems of the prior art, and has as its object to provide a very small image which provides a clear and less distorted observation image even at a wide angle of view. An object of the present invention is to provide an observation device and a prism optical element used for the observation device.

[0013]

According to the present invention, there is provided a prism optical element comprising a plurality of surfaces sandwiching a medium having a refractive index (n) of more than 1 (n> 1). In the element, the prism optical element comprises:
A first surface having a combined effect of transmitting light rays into the prism optical element or emitting light rays from the inside of the prism optical element and internal reflection action inside the prism optical element; and A second surface having an internal reflection function inside the prism optical element and opposed to the first surface with the first surface interposed therebetween; and a second surface arranged at a position substantially close to the second surface and sandwiching the first surface and the medium. When the first surface has a function of causing a light ray to enter the inside of the prism optical element, the light ray is emitted from the inside of the prism optical element when the first face has an internal reflection action inside the prism optical element. When the first surface has the function of emitting light rays from inside the prism optical element, the light rays enter the prism optical element. Having a fourth surface and having a transmitting action such as those having a refractive index at the d-line of the medium n _d,
The angle of internal reflection of an arbitrary ray on the third surface is θ _r3
When a, is characterized in satisfying the _{^{sin -1 (1 / n d)}} ≦ θ r3 ≦ 60 ° ··· (1).

In the present invention, the second surface and the third surface are not limited to a configuration in which separately designed surfaces are arranged adjacent to each other. This also includes a case where the region surface acts as the second surface and another part of the surface acts as the third surface. At this time, since the light beam has a certain width, it goes without saying that there may be an overlap region that acts as both the second surface and the third surface.

One image observation apparatus according to the present invention is an image observation apparatus having an image forming means and an eyepiece optical system having an action of guiding an image formed by the image forming means to an observation eyeball. The system has a prism member having a surface configuration having at least three surfaces filled with a single medium having a refractive index (n) of greater than 1 (n> 1), and the prism member is formed of the image forming means. And has a function of internally reflecting light rays emitted from at least three times, and at least two of the at least three internal reflection actions are reflections by a total reflection action. At least one reflection of the at least two total reflection actions is performed by a surface of the prism member disposed on the observer side of the single medium, and the surface is formed of the prism member. It is formed in a curved shape having a function of correcting an aberration caused by internal reflection, further, at least in the at least three surfaces of the prism member 2
The at least two surfaces are opposed to each other so as to reduce distortion generated when observing the outside with the single medium therebetween so that the outside can be observed through one surface. Things.

According to another aspect of the present invention, there is provided an image observation apparatus comprising: an image forming unit; and an eyepiece optical system having an operation of guiding an image formed by the image forming unit to an observation eyeball. The optical system includes at least a prism member, and the prism member has at least four optically active surfaces having transmission or reflection optical functions in its surface configuration, and the four optically active surfaces and the other optically active surfaces. The refractive index (n) is larger than 1 in the area surrounded by the surface (n> 1)
The four optically active surfaces are configured by being embedded in a single medium.
A first surface having a transmitting action and a reflecting action and disposed on the observer's eyeball side, and disposed opposite to the first surface with the medium interposed therebetween and at least eccentric or inclined with respect to the observer's visual axis; A second surface having a reflection function disposed thereon;
And a second surface disposed opposite to the surface with the medium therebetween.
A third surface having a reflective action disposed substantially adjacent to the surface, one end of the third surface being substantially adjacent to the first surface, and the other end being the third surface;
A fourth surface disposed so as to be substantially close to the surface, wherein the prism member is configured so that at least the third surface has a total reflection effect, and the first surface, the simple substance medium, and the The first surface, the simple substance medium, and the third surface are configured so as to have an external observation function of observing the external world through the three surfaces.

Still another image observation device of the present invention is:
In an image observation device having an image forming unit and an eyepiece optical system having an action of guiding an image formed by the image forming unit to an observation eyeball, the eyepiece optical system includes at least a prism member, and the prism member includes: In the surface configuration, at least four optically active surfaces having a transmission or reflection optical effect are provided, and the refractive index (n) is larger than 1 between the four optically active surfaces ( n> 1) embedded in a single medium, wherein the four optically active surfaces have a transmissive action and a reflective action and are arranged on the observer's eyeball side; A second surface having a reflective action disposed opposite to the medium and disposed at least eccentric or inclined with respect to the observer's visual axis; and a second surface disposed opposite to the first surface with the medium interposed and Reflection placed almost adjacent to two surfaces And a fourth surface having one end substantially adjacent to the first surface and the other end substantially adjacent to the third surface, and at least the second surface. Alternatively, the prism member is configured so that the third surface has a total reflection effect, and the observer is positioned near an area where the second surface or the third surface having the total reflection effect causes the total reflection effect. A gaze detecting means having an action of detecting a gaze is arranged.

In the present invention, the second surface and the third surface are not limited to the configuration in which separately designed surfaces are arranged adjacent to each other, and a part of the surfaces may be formed by using one and the same surface. This also includes a case where the region surface acts as the second surface and another part of the surface acts as the third surface. At this time, since the light beam has a certain width, it goes without saying that there may be an overlap region that acts as both the second surface and the third surface.

Hereinafter, the configuration, operation, and effects of the prism optical element, the image observation device, and the image display device of the present invention will be described. In particular, in the description of the image observation apparatus and the image display apparatus, based on the inverse ray tracing that traces light rays from the observer's pupil position toward the image display element unless otherwise specified, from the viewpoint of design convenience of the optical system. Will be explained.

In this image observation apparatus, the light path from the image display element (image forming means) is internally reflected three times in the eyepiece optical system, so that the effect of folding the optical path is enormous. Optical system is realized. Furthermore, by making two reflections out of the three internal reflections as total reflections, the area of the reflection coating is extremely reduced, and a small, lightweight and low-cost eyepiece optical system has been successfully realized. . Further, by making two reflections out of the three reflections a total reflection, it is possible to reduce the generation of a ghost image due to the generation of unnecessary light or the decrease in contrast due to flare. Generally, in an optical system having an internal reflection filled with an optical medium having a refractive index larger than 1, the influence of unnecessary light due to light having a large exit angle from an image display element, reflection that is not a normal light path, and the like is a problem. Become. In the present invention, by using two total reflection surfaces, the number of reflection coating surfaces is reduced, so that unnecessary light other than the original light flux reaching the pupil from the image display element is transmitted through the two internal reflection surfaces, Unwanted light reaching the observer pupil is significantly reduced.

This operation will be described in detail with reference to FIG. FIG. 20 shows three surfaces 101 decentered with respect to the optical axis.
FIG. 5 is an enlarged view of a portion of the eccentric prism 12 where light from the image display element 7 is incident, in which a space formed by 102 and 103 is filled with a medium having a refractive index larger than 1.
Reference numeral 15 denotes an observer's eyeball, 101 denotes an incident surface, 102 denotes a reflection surface or a total reflection surface on the outside, and 103 denotes a refraction or reflection surface on the observer side. FIG. 20A shows a case where the reflection surface 102 is coated with a reflection coating, and FIG. 20B shows a case where the reflection surface 102 is a total reflection surface and is not coated with a reflection coating. In the case of FIG. 20A, light having a large exit angle emitted from the left side of the image display element 7 is incident on the incident surface 101 of the eccentric prism 12, is refracted, is reflected on the reflective coating-coated reflective surface 102, and is refracted. The light passes through 103 and enters the observer's eyeball 15. Therefore, the observer sees an unnecessary electronic image above the observer's field of view other than the image of the regular image display element 7 (hereinafter, electronic image), or a flare occurs above.

In the case of FIG. 20B, light having a large exit angle emitted from the left side of the image display element 7 is incident on the incident surface 101 of the eccentric prism 12 and is refracted. Since the incident angle is smaller than the critical angle, the light is transmitted. Therefore, this light is transmitted to the opposite side of the observer, and does not enter the observer's eyeball 15. That is, no ghost image or flare occurs.

The operation described above can be similarly produced on the total reflection surface in other than this example. The luminous flux in the beam path for observing a regular electron image is set to have an incident angle that is equal to or greater than the critical angle, and the luminous flux at an exit angle that may cause other ghosts or flares is less than the critical angle on the total reflection surface. This can be achieved by setting as follows. Further, by setting the total reflection surface to two surfaces, it is easy to obtain the above-described effect, and it is possible to provide a clear observation image with no ghost image for the observer and a decrease in contrast due to flare. Becomes

First, assuming that the prism optical element of the present invention is used as an eyepiece optical system (observation optical system) of an image observation apparatus or an image display apparatus, the prism optical element generates at least three internal reflections. Since the prism member is filled with a medium having a refractive index larger than 1, the eyepiece optical system can be made extremely thin by the above-mentioned folding effect of the optical path, and at least internal reflection occurs three times or more. With such a configuration, the effect of aberration correction becomes enormous, and it is possible to present a clear observation image to every corner of the screen. This will be described in detail below.

The main power of the prism optical element is given by the second surface which is a reflection surface. In this case, it is possible to reduce the occurrence of aberration because it can be configured with a larger radius of curvature than a refracting system having the same power. Then, the reflection surface on the outside world is divided into two different surfaces (the second surface and the third surface).
By dividing the light into surfaces, it is possible to set the reflected light in a preferred direction without depending on the curvature of each surface. Therefore, make the shape of the optical system along the observer's face,
The rear surface of the image display device can be arranged so as to face the observer. In particular, when the image display element requires a backlight such as an LCD, the backlight and the electric system are provided on the observer side, so that the entire image display device does not protrude forward and is minimized. it can.

In general, when the concave mirror is arranged eccentrically or inclined with respect to the optical axis, an eccentric aberration which does not occur in the coaxial system occurs. Also in the prism optical element of the present invention, when used in an image observation device or an image display device, since the second surface is eccentric or inclined with respect to the observer's visual axis, eccentric aberration occurs. In particular, even on the axis, the power in the direction along the plane including the optical path of the axial principal ray (tangential direction) and the direction perpendicular to the plane including the optical path of the axial principal ray including the visual axis (sagittal direction) are high. Due to the difference, astigmatism and coma occur. In order to correct these eccentric aberrations, at least one of at least four surfaces constituting the prism optical element is constituted by a surface having different powers in the tangential direction and the sagittal direction, that is, a rotationally asymmetric surface. This makes it possible to correct the eccentric aberration generated on the second surface.

Further, it is effective to form a plane having only one plane of symmetry. When the image display element is arranged on the observer's visual axis (on-axis principal ray), at least one surface constituting the eyepiece optical system is a surface having a plane of symmetry in the sagittal direction, so that the observer's eyeball is formed. On the other hand, a symmetric observation image can be projected. On the other hand, if the surface does not have a symmetrical surface in the tangential direction, the degree of freedom in the tangential direction increases, and the eccentric aberration occurring in the plane including the optical path of the axial chief ray is better corrected. It becomes possible.

When the above-mentioned eyepiece optical system is composed of at least four surfaces, the reflection of the first surface may be total reflection. By making the first surface, which is the surface located immediately before the observer's pupil, the total reflection, it is possible to make the region where the light beam is emitted from the eyepiece optical system overlap the internal reflection region. That is, two functions can be shared by one surface, and the eyepiece optical system can be made compact.

Further, since the effect of reducing ghost and flare by the above-mentioned total reflection surface can be obtained also on the first surface, a clearer observation image can be provided. Furthermore, since the reflective coating is only on the second surface, the manufacturability is improved, and a less expensive image display device can be realized.

[0030] In the above prim optical element, the refractive index n _d for the d-line of the medium, when the angle of internal reflection of any ray in the third surface and ^{_{θ r3, sin -1 (1 /}} n d ) ≦ θ _r3 ≦ 60 ° It is desirable to satisfy the following _expression (1). It is important to satisfy the expression (1). The lower limit sin ^-1 (1 /
By setting n _d ) or more, the internal reflection angle on the third surface becomes equal to or more than the critical angle, and an arbitrary light ray emitted from the image display element can be totally reflected on the third surface.

If the reflection angle on the third surface is too large, the prism optical element will be long in the direction perpendicular to the visual axis (tangential direction). In particular, in the case of an image display device having a wide angle of view, the first off-axis ray is reflected next.
It spreads too far to reach the surface, making it impractical. Therefore, it is desirable that an arbitrary light beam emitted from the image display element is set at 60 ° or less on the third surface, which is the upper limit of the expression (1).

Furthermore, it is desirable to be satisfy _{^{sin -1 (1 / n d)}} ≦ θ r3 ≦ 50 ° ··· (2). Since the third surface is a curved surface that is inclined or decentered with respect to the optical axis (on-axis principal ray), the smaller the reflection angle on this surface is, the smaller the occurrence of aberration due to eccentricity, particularly the generation of eccentric coma.
Therefore, any light beam emitted from the image display element is the third light beam.
It is desirable that the angle be set to 50 ° or less, which is the upper limit of the expression (2).

It is important that at least one surface constituting the prism optical element is flat in order to realize an inexpensive image display device. Since other surfaces can be defined based on at least one plane, mechanical design and manufacture of the optical system can be facilitated. As a result, the processing time can be shortened, the layout of the entire apparatus can be easily arranged, and the like, and significant cost reduction can be realized.

The same effect can be obtained by making at least one surface spherical. In this case, since it is easy to define the other surface with reference to at least one spherical surface, the layout of the entire apparatus is simplified, and the cost can be significantly reduced.

The refractive index n of the medium of the prism optical element
Is preferably greater than 1.3.

It will be apparent from the above description that the above-described prism optical element can be arranged inside the observation optical system to constitute the observation optical system.

In this case, the prism optical element can be arranged inside the objective lens, or can be arranged behind the objective lens, and inside the image erecting means having the function of erecting the object image formed by the objective lens. Can also be placed. In the latter, the prism optical element can have not only an image erecting function but also an eyepiece function.

Further, an image forming means composed of an LCD (liquid crystal display element) and a CRT disposed opposite to the fourth surface of the above prism optical element, or an image formation composed of an LCD or a CRT relayed by a relay optical system. Means for holding the prism optical element and the image forming means on the observer's face. Using the prism optical element of the present invention as a head mounted image display device that is incident on the head, is reflected on the third surface, is reflected on the first surface, is reflected on the second surface, and is emitted from the first surface. Can be.

In the present invention, the second surface and the third surface can be used as the same surface. In that case, since the number of physical surfaces can be reduced by one, the process can be simplified in optical design and prism production, which contributes to mass productivity and reduction in price. Furthermore, if a single surface is used so as to have both the second surface effect and the third surface effect, and the region where the light flux is internally reflected is partially overlapped, the size of the prism member can be reduced. Can be realized and is desirable.

According to another aspect of the present invention, there is provided an image observing apparatus having an image forming means and an eyepiece optical system having an action of guiding an image formed by the image forming means to an observation eyeball. The eyepiece optical system has a refractive index (n) of 1 between
At least 3 filled with a single medium larger than (n> 1)
A prism member having a surface configuration having three surfaces, wherein the prism member has an action of internally reflecting a light beam emitted from the image forming means at least three times, and has at least three internal reflection actions thereof. And at least one of the at least two total reflections is an observer of a single medium of the prism member. The surface is formed by a surface arranged on the side, and the surface is formed in a curved shape having a function of correcting aberration caused by internal reflection of the prism member, and at least three surfaces of the prism member 2
The at least two surfaces are opposed to each other so as to reduce distortion generated when observing the outside with the single medium therebetween so that the outside can be observed through one surface. Things.

In the image observation apparatus of the present invention, since the third surface 5 is a total reflection surface and has no reflection coating, the third surface 5
The external light transmitted through the first surface 3 reaches the observer's eyeball 15. Therefore, the outside world can be observed in a range α different from the observation range β of the electronic image. As described above, the fact that the observer can observe the external image and the electronic image for each partial region means that, for example, the observer observes the external environment in the upper region and simultaneously observes the electronic image in the lower region in the observer's field of view. That is what you can do. However, this partial area means, in any direction, such as up and down, left and right, if the observer can partially observe each,
It may be divided into areas. With such a function, the observer can recognize the outside world while wearing the image display device, so that it is possible to provide a safe image display device capable of preventing danger and responding to an emergency. Therefore, the range of applications as the image display device is expanded.

In this image forming apparatus, the image forming means includes an LCD, a C, and an LCD having an image forming screen opposed to the fourth surface.
It is an image display element such as an RT (it is not planned to be relayed by a relay optical system), and the second surface is desirably formed of a curved surface.

Also, in such an image forming apparatus, a holding member having an action of holding the image display element and the eyepiece optical system in front of the observer's eyeball is provided, and the prism member emits a light beam emitted from the image display element. The light enters from the fourth surface, the incident light beam is reflected by the third surface, the reflected light beam is reflected by the first surface, the reflected light beam is reflected by the second surface, and the reflected light beam is emitted from the first surface. With such a configuration, the head-mounted image display device can be configured.

In the above-described image observation apparatus, the prism member may be fixed at the same position in both observation of the image formed by the image forming means and observation of the external image. In that case, FIG. 7 below
It is desirable that the image from the image forming means and the external image can be observed for each partial area through the first surface and the third surface, as described with reference to FIG.

The prism member may be provided with switching means for switching between observation of an image formed by the image forming means and observation of an external image, and the prism member may be moved by the switching means.

That is, the first surface disposed immediately before the observer's eyeball of the eyepiece optical system and the third surface disposed on the outside world side and partially reflecting the principal ray are near the observer's visual axis. By moving the observer in this way, the observer can observe an external image around the visual axis when facing straight ahead, that is, near the center of the visual field, so that the observer can observe the external image in front of the observer's eyes while wearing the image display device. Since the outside world can be confirmed, an image display device that ensures safety can be realized.

Further, if the electronic image is displayed, the user can check the switching between the external image and the electronic image by moving or returning the eyepiece optical system, so that the range of applications can be expanded. Become.

In this case, the switching means changes the optical path from the prism member to the observer's eyeball when observing the image formed by the image forming means, from the prism member when observing and observing the external image. It is desirable that the prism member be moved so as to substantially coincide with the optical path reaching.

If the movement of the prism member is made to move in the direction along the plane including the optical path of the axial chief ray, the movement becomes linear, so that the layout of the moving mechanism and the entire apparatus becomes easy, and the cost is reduced. A simple image display device can be realized.

Further, if the prism member can be moved in the direction perpendicular to the visual axis, it goes without saying that the layout and moving mechanism of the entire apparatus are easy, and even after the eyepiece optical system is moved, the prism member can be moved to the front of the observer. Since the protrusion amount of the image display does not change, a small and compact image display device can be provided.

When the prism member is rotatable,
Because it is possible to observe the outside world by moving the prism member by the easy rotation mechanism of the prism member,
Since the mechanism itself is inexpensive, and furthermore, it is possible to confirm the outside world with both eyes by simultaneously rotating left and right, so that safety is enhanced and the layout of the apparatus can be realized with a simple configuration.

Further, another image observation apparatus of the present invention comprises:
In an image observation device having an image forming unit and an eyepiece optical system having an action of guiding an image formed by the image forming unit to an observation eyeball, the eyepiece optical system includes at least a prism member, and the prism member includes: In the surface configuration, at least four optically active surfaces having an optical effect of transmission or reflection are provided, and a refractive index (n) is defined between the four optically active surfaces and other surfaces. Greater than 1 (n
> 1) The four optically active surfaces are configured to be embedded in a single medium, and the four optically active surfaces have a transmissive action and a reflective action, and are disposed on the observer's eyeball side; A second surface having a reflective action, which is arranged to face the observer's visual axis at least eccentrically or inclined, and the second surface is arranged to face the first surface with the medium interposed therebetween; A third surface having a reflection function disposed substantially adjacent to the surface, and a fourth surface disposed such that one end is substantially adjacent to the first surface and the other end is substantially close to the third surface. And the prism member is configured so that at least the third surface has a total reflection effect.
The first surface, the simple substance medium, and the third surface are configured to have an external observation function of observing the external world through a surface, the simple substance medium, and the third surface. Is what you do. In the above description, surfaces other than the four optically active surfaces mean prism side surfaces or cut surfaces having no optical effect.

These image observation devices are configured so that the external world can be observed through a surface disposed immediately before the observer's eyeball and a surface disposed on the external side of the eyepiece optical system. This operation and effect will be described with reference to FIG.
FIG. 7 is a cross-sectional view of an eccentric prism 12 in which a space formed by four surfaces 3, 4, 5, and 6 decentered with respect to the optical axis is filled with a medium having a refractive index larger than 1. Is the observer's pupil, 2 is the observer's visual axis, 3 is the first surface of the eyepiece optical system 12, 4 is the second surface, 5 is the third surface, 6 is the fourth surface,
7 is an image display element, 12 is an eyepiece optical system, 15 is an observer's eyeball, 16 is an optical filter, and a ray path from the actual image display element 7 is a light ray emitted from the image display element 7,
The light enters the fourth surface 6 of the eyepiece optical system 12, is totally reflected by the third surface 5, is totally reflected by the first surface 3, is reflected by the second surface 4, passes through the first surface again, and passes through the first surface. An image is projected on the observer's eyeball 15 with the pupil 1 as an exit pupil.

In the image observation apparatus of the present invention, since the third surface 5 is a total reflection surface and has no reflection coating, the third surface 5
The external light transmitted through the first surface 3 reaches the observer's eyeball 15. Therefore, the outside world can be observed in a range α different from the observation range β of the electronic image. As described above, the fact that the observer can observe the external image and the electronic image for each partial region means that, for example, the observer observes the external environment in the upper region and simultaneously observes the electronic image in the lower region in the observer's field of view. That is what you can do. However, this partial area means, in any direction, such as up and down, left and right, if the observer can partially observe each,
It may be divided into areas. With such a function, the observer can recognize the outside world while wearing the image display device, so that it is possible to provide a safe image display device capable of preventing danger and responding to an emergency. Therefore, the range of applications as the image display device is expanded.

In this image forming apparatus, the image forming means includes a CLD, a CLD having an image forming screen opposed to the fourth surface.
It is an image display element such as an RT (it is not planned to be relayed by a relay optical system), and the second surface is desirably formed of a curved surface.

Further, in such an image forming apparatus, a holding member having an action of holding the image display element and the eyepiece optical system in front of the observer's eyeball is provided, and the prism member emits a light beam emitted from the image display element. The light enters from the fourth surface, the incident light beam is reflected by the third surface, the reflected light beam is reflected by the first surface, the reflected light beam is reflected by the second surface, and the reflected light beam is emitted from the first surface. With such a configuration, the head-mounted image display device can be configured.

In the above-described image forming apparatus, the surface disposed immediately before the observer's eyeball and the surface disposed on the external side of the eyepiece optical system are arranged at arbitrary positions of the two surfaces with respect to external light. It is desirable that the combined power at is approximately zero. When the combined power of the two surfaces with respect to the external light is substantially zero, the state of observing the external image becomes substantially the same as observing with the naked eye, and a more natural external world can be observed. Therefore, the outside world can be accurately recognized in the event of danger prevention or emergency, so that an extremely safe image display device can be provided.

In this case, the first surface and the third surface can be formed as curved surfaces, spherical surfaces, or flat surfaces. When the observer observes the external world, light rays from the external world are transmitted through the area of total internal reflection among the internal reflection planes arranged on the external world side and the refraction plane arranged just before the observer's eyeball. Is projected on the human pupil. Here, by making these two surfaces spherical rather than aspherical, there is no change in the curvature of each surface, so that it becomes easy to observe a more natural external image outside the axis. In addition, if the first surface disposed immediately before the observer's eyeball and the third surface disposed on the external side of the eyepiece optical system are flat, each surface has no power, so that a natural external world can be observed. further,
When the two surfaces are perpendicular to the observer's visual axis and are arranged parallel to each other, the observer simply observes the external world through a transparent plate, and thus observes a very natural external image. It becomes possible.

[0059] When in these, the combined power at any location between the surface which is disposed on the external side of the viewer side and the eyepiece optical system is disposed on the eyeball immediately before against external light and phi _t1, -0. 5 ≦ φ _t1 ≦ 0.5 (1 / mm) It is desirable to satisfy the following expression (3). Here, φ _t1 corresponds to the power φ _t1 (yz) in the plane including the axial chief ray and the power φ _t1 (xz) in the plane perpendicular to the plane. By satisfying the condition of equation (3), the magnification when external light is transmitted through the eccentric prism can be set to be close to unity.
You can observe the more natural outside world.

In the above-described image observation apparatus, the prism member may be fixed at the same position in both observation of the image formed by the image forming means and observation of the external image. Yes, in that case, FIG.
As described above, it is desirable that the image from the image forming unit and the external image can be observed for each partial region through the first surface and the third surface.

The prism member may be provided with switching means for switching between observation of an image formed by the image forming means and observation of an external image, and the switching means may move the prism member.

That is, the first surface disposed immediately before the observer's eyeball of the eyepiece optical system and the third surface disposed on the outside and partially reflecting the principal ray are near the observer's visual axis. By moving the observer in this way, the observer can observe an external image around the visual axis when facing straight ahead, that is, near the center of the visual field, so that the observer can observe the external image in front of the observer's eyes while wearing the image display device. Since the outside world can be confirmed, an image display device that ensures safety can be realized.

Further, if the electronic image is displayed, the user can check the switching between the external image and the electronic image by moving or returning the eyepiece optical system, so that the range of applications can be expanded. Become.

In this case, the surface arranged immediately before the observer's eyeball and the surface arranged on the outside of the eyepiece optical system are set so that the combined power of the two surfaces with respect to the outside light is substantially zero. It is desirable. An observer is able to observe a more natural external environment when the combined power of the two surfaces with respect to external light is substantially zero, to provide a very safe image display device capable of preventing danger and appropriately responding to an emergency. Can be.

[0065] Then, when the combined power at any location between the surface which is disposed on the external side of the viewer side and the eyepiece optical system is disposed on the eyeball immediately before against external light and phi _t2, -0.5 ≦ φ _t2 ≦ 0.5 (1 / mm) (4) Here, φ _t2 corresponds to the power φ _t2 (yz) in the plane including the axial principal ray and the power φ _t2 (xz) in the plane perpendicular to the plane. By satisfying the condition of the expression (4), the magnification when the external light passes through the eccentric prism can be set to near 1, so that
You can observe the more natural outside world.

In this case, the switching means changes the optical path from the prism member to the observer's eyeball when observing the image formed by the image forming means, from the prism member when observing and observing the external image. It is desirable that the prism member be moved so as to substantially coincide with the optical path reaching.

If the movement of the prism member is made to move in the direction along the plane including the optical path of the axial chief ray, the movement becomes linear, so that the layout of the moving mechanism and the entire apparatus becomes easy, and the cost is reduced. A simple image display device can be realized.

If the movement of the prism member can be moved in the direction perpendicular to the visual axis, it goes without saying that the layout and movement mechanism of the entire apparatus are easy, and even after the movement of the eyepiece optical system, the prism member can be moved to the front of the observer. Since the protrusion amount of the image display does not change, a small and compact image display device can be provided.

When the prism member is rotatable,
Because it is possible to observe the outside world by moving the prism member by the easy rotation mechanism of the prism member,
Since the mechanism itself is inexpensive, and furthermore, it is possible to confirm the outside world with both eyes by simultaneously rotating left and right, so that safety is enhanced and the layout of the apparatus can be realized with a simple configuration.

Still another image observation device of the present invention is:
In an image observation device having an image forming unit and an eyepiece optical system having an action of guiding an image formed by the image forming unit to an observation eyeball, the eyepiece optical system includes at least a prism member, and the prism member includes: In the surface configuration, at least four optically active surfaces having an optical effect of transmission or reflection are provided, and a refractive index (n) is defined between the four optically active surfaces and other surfaces. Greater than 1 (n
> 1) The four optically active surfaces are configured to be embedded in a single medium, and the four optically active surfaces have a transmissive action and a reflective action, and are disposed on the observer's eyeball side; A second surface having a reflective action, which is arranged to face the observer's visual axis at least eccentrically or inclined, and the second surface is arranged to face the first surface with the medium interposed therebetween; A third surface having a reflection function disposed substantially adjacent to the surface, and a fourth surface disposed such that one end is substantially adjacent to the first surface and the other end is substantially close to the third surface. And the prism member is configured so that at least the second surface or the third surface has a total reflection effect, and the second surface or the third surface having the total reflection effect is formed.
A gaze detecting means having an action of detecting the gaze of the observer is arranged near an area where a total reflection action of the surface occurs. Also in this case, the surfaces other than the four optically active surfaces mean prism side surfaces or cut surfaces having no optical effect.

The operation and effect when the image observation device is configured as an image display device will be described below. By arranging the line of sight detection means near the optical system, it is possible to detect the line of sight of the observer. Here, gaze detection will be described with reference to FIGS. FIG. 5A shows an image display comprising an eccentric prism 12 and an image display element 7 in which a space formed by three surfaces 3, 4, 6 decentered with respect to the optical axis is filled with a medium having a refractive index larger than 1. FIG. 5 (b) is a sectional view of the device, and FIG. 5 (b) shows an image formed by an eccentric prism 12 filled with a medium having a refractive index larger than 1 in a space formed by four surfaces 3, 4, 5, and 6 decentered with respect to the optical axis. FIG. 6 is a cross-sectional view of an image display device including a display element 7, and FIG.
The decentered prism 12 and the image display element 7 which fill the space formed by 6 with a medium having a refractive index larger than 1.
FIG. 1 is a cross-sectional view of another image display device comprising: 1 is an observer's pupil, 2 is an observer's visual axis, 3 is a first surface of the eyepiece optical system 12, 4 is a second surface, and 5 is The third surface, 6 is the fourth surface,
7 is an image display element, 9 is a visual axis detection optical system, 10 is a visual axis detector, 11 is illumination means, 12 is an eyepiece optical system, and 15 is an observer's eyeball.

FIG. 5A is a view in which the visual line detecting means 9 and 10 are arranged on the outside facing the observer's eyeball 15 with the eccentric prism of the eyepiece optical system 12 interposed therebetween. In this case, the image of the observer pupil 1 includes a first surface 3 disposed immediately before the observer pupil 1,
It is necessary that the light passes through the second surface 4 which is a reflection surface disposed on the external side of the eyepiece optical system 12 and is incident on the visual line detection means 9 and 10. However, since the second surface 4 arranged on the outside world side of the eyepiece optical system 12 is a reflective surface, it is coated with a reflective coating. In order to guide the image of the observer pupil 1 to the visual line detecting means 9 and 10, Part NC that does not have reflective coating on reflective surface
(A coating hole) is required, which adversely affects the image to be observed.

FIGS. 5B and 6 show an image display device which is an image observation device of the present invention. The third surface 5, which is a reflection surface disposed on the outside world side of the eyepiece optical system 12, is set so as to partially partially reflect. The total reflection portion reflects light from the image display element 7 even without the reflective coating, so that the reflective coating is not required.
The light passes through the total reflection portion of the first surface 3 disposed immediately before the observer pupil 1 and the third surface 5 disposed on the external side of the eyepiece optical system, and can be detected by the line-of-sight detection means 9 and 10. Therefore, it is possible to detect the line of sight without creating a coating hole on the reflecting surface of the eyepiece optical system 12 that adversely affects the observation of the electronic image.

In this case, it is desirable that the first surface of the decentered prism has a total reflection function. In this case, it is desirable that the line-of-sight detecting means is disposed at a position where the line-of-sight detecting means detects the line of sight of the observer through the total reflection area of the second surface or the third surface.

It is desirable to have illumination means for illuminating the observer's eyeball. Since this image display device can detect a brighter image than illuminating the observer's eyeball, it is possible to detect an accurate line of sight of the observer. Further, it is desirable that the illuminating means is provided outside the eyepiece optical system. FIG.
As shown in (a), when the lens is disposed between the observer's face and the eyepiece optical system 12, there is a fear that the lens may interfere with eyeglasses or the like. However, as shown in FIG. 5B, when the illuminating unit 11 is arranged outside the eyepiece optical system 12, the illuminating unit 11 can be arranged to avoid interference with the observer's face. Further, by arranging the illumination light from the illumination means 11 so as to pass through the total reflection part of the reflection surface of the eyepiece optical system 12, the observer pupil can be illuminated without forming a coating hole. Preferably, the means uses infrared light. Observing the electronic image means that the observer's pupil is immediately illuminated by the light of the image display element. In a line-of-sight detection unit that needs to capture a weak virtual image and perform image analysis, such as a corneal reflection method, it is necessary to eliminate a reflected image due to a light flux of an image display element whose irradiation light quantity changes every moment. Usually, the image display element is an LCD or the like, and the emitted light is in a visible wavelength range. Therefore, the influence of light from the image display element can be reduced by using infrared light for the illumination means.

Also in this case, a head-mounted image display device can be provided by providing a holding member having an action of holding the eyepiece optical system, the image forming means, and the visual line detection means on the observer's face.

Further, in the above-mentioned image observation apparatus, it is possible to have a positioning means for positioning the image forming means and the eyepiece optical system with respect to the observer's head.

Further, by providing a supporting means for supporting at least two sets of such an image observation device at a fixed interval, a stereoscopic image or the like can be observed with both eyes.

Next, an image display device according to the present invention is an image display device comprising: an image display device; and an eyepiece optical system for guiding an image formed by the image display device so that the image can be observed as a virtual image. System is at least 2
The space formed by the surfaces is filled with a medium having a refractive index greater than 1, and a first surface located immediately before an observer's eyeball and a second surface that is a reflection surface facing the first surface, An eccentric prism having at least one surface formed of a curved surface that is eccentric or inclined with respect to the observer's visual axis, and disposed outside the second surface; And an aberration correcting means having a function of correcting aberration caused by eccentricity generated on the surface.

In this image display apparatus, when observing an external image via a first surface located immediately before the observer's eyeball and a second surface which is a reflecting surface facing the first surface, the two surfaces are used. Is at least one surface eccentric or inclined with respect to the observer's visual axis, so that it is the same as observing the outside world through a lens having asymmetrical biased power with respect to the optical axis. Therefore, by arranging aberration correction means such as a Fresnel lens that cancels out the biased power toward the outside of the second surface, the observer can observe a more natural outside. Further, since the Fresnel lens is an extremely thin optical element, a small-sized image display device can be provided without increasing the size of the device.

In the present invention, the Fresnel lens is another optical element if the above-mentioned effects can be obtained, for example,
It may be replaced with a diffractive optical element, a holographic optical element, or the like.

When a Fresnel lens is used, the center of the annular zone of the Fresnel lens is in a plane including the optical path of the axial principal ray from the image display device, and the Fresnel lens includes the optical path of the axial principal ray. It is desirable that the eccentricity be perpendicular to the visual axis in the plane. If the Fresnel lens has an axially symmetric shape, it is excellent in manufacturability and cost can be reduced. By arranging a Fresnel lens having axially symmetric power in a plane including an optical path of an axial chief ray in an eccentric manner with respect to the visual axis, an aberration caused by eccentricity generated on the first surface and the second surface with respect to external light. Can be better corrected.

Further, the center of the annular zone of the Fresnel lens is on a plane including the optical path of the axial principal ray, and the Fresnel lens is arranged to be inclined with respect to the visual axis, and the inclination direction is the second plane. You may make it arrange | position in the direction which follows a surface shape. Arranging the Fresnel lens along the surface shape of the second surface means that the Fresnel lens is inclined with respect to the observer's visual axis. Therefore, it is possible to set a biased power that is asymmetric with respect to the optical axis, and the first surface and the second surface with respect to external light.
It is possible to better correct aberration caused by eccentricity occurring on the surface. Furthermore, the amount of projection to the observer and the space between the eyepiece optical system and the Fresnel lens are reduced, and a very compact image display device without waste can be provided.

According to another aspect of the present invention, there is provided an image forming apparatus comprising: an image display device; and an eyepiece optical system for guiding an image formed by the image display device so that the image can be observed as a virtual image. The system fills a space formed by at least three surfaces with a medium having a refractive index greater than 1, wherein the at least three surfaces are a refraction and internal reflection surface located immediately before an observer's eyeball, An external-side internal reflection surface facing the reflection surface and disposed on the external side of the eyepiece optical system, and a refraction surface to which a light beam emitted by the image display element is incident, at least one of the surfaces,
It is composed of a plane that is eccentric or inclined with respect to the observer's visual axis,
An eccentric prism having at least three internal reflections;
When observing the external world via the refraction and internal reflection surface located immediately in front of the observer's eyeball and the external world-side internal reflection surface, an external light having the effect of canceling the power generated on the two surfaces against the external light. The optical system comprises two optical elements, wherein the second optical element is arranged on the external side of the external-side internal reflection surface.

A first surface located immediately before the observer's eyeball;
When observing an external image via the second surface, which is a reflecting surface facing the first surface, at least one of the two surfaces is eccentric or inclined with respect to the observer's visual axis. It is the same as observing the outside world through a lens having different biased power depending on the height. Therefore, by arranging the second optical element having a function of canceling the biased power generated on the two surfaces with respect to the external light on the external side of the eyepiece optical system, the observer can obtain a more natural and wide external image. Can be observed. Therefore, danger prevention and emergency response can be performed, and a safe image display device can be provided.

In this case, the eyepiece optical system fills the space formed by the four surfaces with a medium having a refractive index greater than 1,
The first surface is a refracting surface and a reflecting surface located on the observer's eyeball side, the second surface is a reflecting surface facing the first surface, and the reflecting surface is opposed to the first surface and is adjacent to the second surface. A third surface, which is a surface, and a fourth surface, which is a refraction surface closest to the image display element, wherein at least one surface is decentered or inclined with respect to the observer's visual axis. It may be. When the eyepiece optical system is composed of four surfaces as described above, the external environment is recognized by the external light transmitted through the first surface and the second surface. In that case, by arranging the second optical element having a function of canceling out the biased power only in the region covering the second surface, it becomes possible to realize the additional function without increasing the size of the entire eyepiece optical system. .

Further, at least one second optical element is provided so that the outside world can be observed through the first surface, the second surface, and the second optical element, or the first surface, the third surface, and the second optical element. It is desirable to dispose it on the outer side of the second surface or the third surface. By disposing the second optical element having a function of canceling the biased power toward the outside of the second surface, a natural outside image can be observed in a region substantially the same as the region where the electronic image is observed. Similarly, by arranging the second optical element having a function of canceling the biased power toward the outside of the third surface, a natural outside can be observed even in a region different from the electronic image. Further, the two second optical elements are simultaneously moved to the second surface and the third surface.
By arranging it on the outer side of the surface, the observer can see the first surface and the second surface.
It is possible to observe all the external images transmitted through the surface and the first and third surfaces. Therefore, the angle of view of the external world is wider than the angle of view of the electronic image, and a natural and wide-range external image can be observed. This makes it possible to prevent danger and appropriately deal with emergencies, and to provide a very safe image display device.

The second optical element desirably has a function of simultaneously canceling the combined power of the first surface and the second surface or the combined power of the first surface and the third surface with respect to external light. A second optical element having a function of simultaneously canceling the combined power of the first surface and the second surface and the combined power of the first surface and the third surface with respect to external light is constituted by one optical element, and is disposed on the external side of the eyepiece optical system. Can observe a wide range of the outside world. The second optical element simultaneously cancels out the respective combined powers, so that the external image can be observed more naturally without a break. Therefore, it is possible to provide an image display device that can recognize a wide range of the external world with one optical element, is inexpensive, can prevent danger, responds to emergencies, and further enhances safety.

Further, in the above, it is possible to have a positioning means for positioning the image display element and the eyepiece optical system with respect to the observer's head. By having the positioning means for positioning the image display element and the eyepiece optical system with respect to the observer's head, the observer can observe a stable electronic image.

Further, the image display device and the eyepiece optical system are provided with support means for supporting the observer's head, and can be mounted on the observer's head. Having a support means for supporting the image display element and the eyepiece optical system with respect to the observer's head,
By being mounted on the observer's head, the observer can observe the electronic image in any observation posture and observation direction.

Further, it is possible to have a support means for supporting at least two sets of the image display device at a constant interval. By having the supporting means for supporting at least two sets at a fixed interval, it becomes possible for the observer to easily observe with both the left and right eyes. In addition, it is possible to enjoy a stereoscopic image by displaying images in which parallax is given to the left and right electronic images and observing them with both eyes.

The eyepiece optical system in the above-described image display device can be used as an image forming optical system. By configuring the image display surface in the eyepiece optical system as an image plane to form an image of an object at infinity, it can be used as an imaging optical system such as a finder optical system of a camera as shown in FIG. It is.

In the present invention, the second surface and the third surface can be used on the same surface. In that case, since the number of physical surfaces can be reduced by one, the process can be simplified in optical design and prism production, which contributes to mass productivity and reduction in price. Furthermore, if a single surface is used so as to have both the second surface effect and the third surface effect, and the region where the light flux is internally reflected is partially overlapped, the size of the prism member can be reduced. Can be realized and is desirable.

[0094]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments 1 to 17 of an image display device according to the present invention will be described below. In the configuration parameters of each embodiment described later, as shown typically in FIG. 1, the exit pupil 1 of the eyepiece optical system 12 is set as the origin of the optical system, and the optical axis 2 is used as the display center of the image display element 7 and the exit pupil. 1 is defined as a light beam passing through the center (origin) of
The direction in which light travels is the Z-axis direction, which is orthogonal to this Z-axis, passes through the center of the exit pupil 1, and the direction in which light rays are bent by the eyepiece optical system 12 is orthogonal to the Y-axis direction, the Z-axis, and the Y-axis. The direction passing through the center is the X-axis direction, the direction from the exit pupil 1 toward the eyepiece optical system 12 is the positive direction of the Z-axis, the direction from the optical axis 2 to the image display element 7 is the positive direction of the Y-axis. The direction forming the right hand system with the Y axis is defined as the positive direction of the X axis. In addition,
Ray tracing is performed by reverse ray tracing with the exit pupil 1 side of the eyepiece optical system 12 as the object side and the image display element 7 side as the image plane side.

The planes on which the amounts of eccentricity Y and Z and the amount of inclination θ are described are the origins of the optical system unless otherwise specified in the constituent parameters (described in Examples 6 and 9). Represents the amount of deviation from the exit pupil 1 in the Y and Z directions and the inclination angle of the center axis of the surface with respect to the Z axis. The tilt angle is positive in the counterclockwise direction. Further, when the reference plane is particularly described, the same shift amount and inclination angle from the top of the reference plane are shown.

In the configuration parameters to be described later, the surface interval of the coaxial portion is shown as the interval. In addition, the radius of curvature of the spherical surface, the refractive index of the medium, and the Abbe number are shown according to a conventional method.

FIGS. 1 to 4 and FIGS. 5 (b) to 17 are sectional views including the optical axis of the image display device according to the first to fourth and fifth to fifth embodiments of the present invention. 5 (b) to 11 and FIG.
In the embodiment of FIGS. 5 to 16, the space formed by the four surfaces 3, 4, 5, 6 decentered with respect to the optical axis is composed of an eccentric prism 12 filled with a medium having a refractive index larger than 1. Further, in the embodiment of FIG. 17, the space formed by the three surfaces 3, 4, 6 decentered with respect to the optical axis is constituted by an eccentric prism 12 filled with a medium having a refractive index larger than 1. In each figure, 1 is the pupil of the observer,
2 is the observer's visual axis, 3 is the first surface of the eyepiece optical system 12, 4 is the second surface, 5 is the third surface, 6 is the fourth surface, 7 is the image display element, 8
Is a Fresnel lens, 9 is a line-of-sight detection optical system, 10 is a line-of-sight detector, 11 is illumination means, 12 is an eyepiece optical system (eccentric prism), 13 and 14 are second optical elements, 15 is an observer's eyeball,
Reference numeral 16 denotes an optical filter, reference numeral 17 denotes a linear motor, reference numeral 18 denotes a protrusion provided on the optical element, reference numeral 19 denotes a guide (rail) provided on an exterior part, and actual light paths when observing an electronic image are shown in FIG. In the embodiments of FIGS. 1 to 4, 5 (b) to 11, and 15 to 16, light rays emitted from the electronic image of the image display element 7 face the image display element 7 of the eyepiece optical system 12. Incident on the fourth surface 6 which is a refracting surface, and is reflected toward the observer pupil 1 by the third surface 5 adjacent to the fourth surface 6 among the two surfaces 4 and 5 located on the opposite side of the observer face. And observer's pupil 1
Is reflected in the direction away from the observer's pupil 1 on the first surface 3 arranged immediately in front of the observer's pupil 1, and is arranged immediately before the observer's pupil 1 among the two surfaces 4, 5 located on the opposite side of the observer's face. Second face 4
Is reflected toward the observer's pupil 1 and transmitted through the first surface 3 to project the observer's iris position or the center of rotation of the eyeball into the observer's eyeball 15 as the exit pupil 1. In addition, Embodiment 17 of FIG.
In, the light beam emitted from the electronic image of the image display element 7 is incident on the fourth surface 6 which is the refraction surface facing the image display element 7 of the eyepiece optical system 12, and is located on the opposite side of the observer's face. In the region (third surface 5) adjacent to the fourth surface 6 of the second surface 4, which also serves as the third surface 5, the first surface 5 is reflected toward the observer pupil 1, and is disposed immediately before the observer pupil 1. The light is reflected on the surface 3 in a direction away from the observer pupil 1, and is reflected on the observer pupil 1 side in a region located on the opposite side of the observer face and far from the fourth surface 6 of the second surface 4,
The light passes through the first surface 3 and is projected into the eyeball 15 of the observer as the exit pupil 1 at the iris position of the observer or the center of rotation of the eyeball.

FIGS. 5B and 6 show an embodiment of the image display apparatus of the present invention having a line-of-sight detecting means.
The third surface 5, which is a reflection surface disposed on the outside world side of the eyepiece optical system 12, is set so as to partially partially reflect. The total reflection portion reflects light from the image display element 7 even without the reflection coating, so that the reflection coating is not required.
The illumination light from the light source 11 passes through the third surface 5 and the first surface 3 of the eyepiece optical system 12 to illuminate the observer's eyeball 15, and the light reflected therefrom is disposed immediately before the observer's pupil 1. First surface 3
And is transmitted through at least a part of the total reflection area of the third surface 5 located on the opposite side of the observer's face, guided to the visual axis detector 10 by the visual axis detection optical system 9, and observed by the observer's pupil. 1
An image is formed. Here, in order to reduce the influence of light such as an electronic image, an illumination 11 of infrared light or a detector 10 for detecting infrared light may be used. Further, the position of the illuminating means 11 may be any place other than the illustrated place as long as the observer's eyeball 15 can be illuminated.

FIG. 18 shows the eye-gaze detecting optical system 9 and the eye-gaze detector in the case of the eyepiece optical system 12 composed of three surfaces 3, 4, and 6 decentered with respect to the optical axis as in the seventeenth embodiment. 1
FIG. 2 is a cross-sectional view in the case where a similar line-of-sight detection unit including a light source 11 is provided. The actual ray path in the case of detecting the line of sight is the same as that in FIGS.

FIG. 7 shows an embodiment of the image display apparatus according to the present invention, in which an electronic image and an external image can be simultaneously observed by the eyepiece optical system 12. When observing an external image, the actual ray path is such that a ray from an object point in the external field enters from the third surface 5, passes through the first surface 3, and exits the iris position of the observer or the center of rotation of the eyeball. The pupil 1 is projected into the eyeball of the observer. Further, by disposing a neutral density filter or an optical element 16 for adjusting the amount of external light on the external side of the third surface 5, the observer can easily observe both or one of the electronic image and the external image. It is also possible. Further, the neutral density filter or the optical element 16 is set in the observation range α.
And β, the light amount of either the electronic image or the external image can be adjusted.

FIGS. 8 and 9 show the eyepiece optical system 1.
2 is an embodiment of another image display device of the present invention capable of observing an external image by moving the image display device 2. In FIG. 8, the eyepiece optical system 12 is moved in the negative Y direction with respect to the observer pupil from the electronic image observation position in FIG.
FIG. 9A shows the external image observation position shown in FIG.
By turning the eyepiece optical system 12 clockwise with respect to the observer pupil 1 from the electronic image observation position of FIG. Therefore, it becomes possible to observe the outside world in the visual axis direction of the observer through the eyepiece optical system 12. Light rays from an object point in the external world enter from the third surface 5,
The light passes through the first surface 3 and is projected into the eyeball of the observer as the exit pupil 1 at the iris position of the observer or the center of rotation of the eyeball. Further, in FIG. 8B, the observer can observe the electronic image in a region below the observer's visual axis 2. Here, the observation direction of the electronic image may be any direction since it differs depending on the arrangement and movement direction of the eyepiece optical system 12.

FIGS. 8C and 9C show examples of the moving mechanism of the eyepiece optical system 12. FIG. In any case, the eyepiece optical system 12 may be moved along the guide (rail) 19 provided on the exterior part by the linear motor 17 via the protrusion 18 provided on the optical element. In the case of FIG. 8C, the guide (rail) 19 is a straight line,
In the case of FIG. 9C, since the guide (rail) 19 is a circular arc, linear movement and rotation are performed, respectively.

In FIG. 19, in the case of the eyepiece optical system 12 composed of three surfaces 3, 4, and 6 decentered with respect to the optical axis as in the seventeenth embodiment, like the embodiment of FIG. An example is shown in which the eyepiece optical system 12 is moved in the negative Y direction with respect to the observer's pupil from the image observation position to become the external image observation position. The operation is the same as that of FIG.

FIGS. 10 to 14 show a Fresnel lens 8 serving as an aberration correcting means in an optical path for observing an external image.
1 is an embodiment of the image display device of the present invention in which is disposed. The actual ray path when observing an external image is as follows: light rays from an object point in the external world pass through the Fresnel lens 8, enter the eccentric prism from the second surface 4, pass through the first surface 3, and are observed. The iris position of the observer or the center of rotation of the eyeball is projected as an exit pupil 1 into the observer's eyeball. Here, the Fresnel lens 8 only needs to be arranged at a predetermined position when observing the external world. When the external world is not observed, the Fresnel lens 8 is disposed at another position by a moving mechanism such as up-down movement or rotational movement, Alternatively, it may be configured to be removable.

In FIGS. 10 to 14, in the cases of FIGS. 10 to 11, the eyepiece optical system (eccentric prism) 12
Is composed of four surfaces 3, 4, 5, and 6 decentered with respect to the optical axis, and follows the same ray path when observing an electronic image.
Is composed of an eccentric prism 12 in which a space formed by three surfaces 3, 4, and 6 decentered with respect to the optical axis is filled with a medium having a refractive index larger than 1, and an electron image is observed. The actual ray path is that the light beam emitted from the electronic image of the image display element 7 is the fourth surface (the third surface in order) which is the refraction surface facing the image display element 7 of the eyepiece optical system 12. 2), and is reflected in a direction away from the observer pupil 1 by the first surface 3 disposed immediately before the observer pupil 1, and a second surface 4 located on the opposite side of the observer face
Is reflected toward the observer's pupil 1 and transmitted through the first surface 3 to project the observer's iris position or the center of rotation of the eyeball into the observer's eyeball 15 as the exit pupil 1.

The eccentric prism 12 shown in FIG. 13 is composed of an eccentric prism 12 in which a space formed by three surfaces 3, 4, and 6 decentered with respect to the optical axis is filled with a medium having a refractive index larger than 1. The actual ray path when observing the electronic image is such that the rays emitted from the electronic image of the image display element 7 are the fourth surface (order) which is the refraction surface facing the image display element 7 of the eyepiece optical system 12. This is the third side)
At the second face 4 located on the opposite side of the face of the observer, is reflected toward the observer pupil 1 side, passes through the first face 3 and changes the iris position of the observer or the center of rotation of the eyeball to the exit pupil 1 Is projected into the eyeball 15 of the observer.

The eccentric prism 12 shown in FIG. 14 is composed of an eccentric prism 12 in which a space formed by two surfaces 3 and 4 decentered with respect to the optical axis is filled with a medium having a refractive index larger than 1. An actual ray path when observing an image is as follows. A ray emitted from an electronic image of the image display element 7 is incident on the first surface 3 which is a refraction surface facing the image display element 7 of the eyepiece optical system 12. The second face 4 located on the opposite side of the face of the observer reflects on the observer pupil 1 side, transmits through the first face 3, and sets the iris position of the observer or the center of rotation of the eyeball as the exit pupil 1. Is projected into the eyeball 15.

Next, FIGS. 15 and 16 show the first surface 3 and the external-side internal reflection surface which are located immediately before the observer's eyeball of the eyepiece optical system 12 in the optical path for observing the external image. When observing the outside through a certain second surface 4 or a third surface 5, the second optical element 13, which has a function of canceling the power generated on the two surfaces 3, 4 or 3, 5 against external light, 14 is an embodiment of the image display device according to the present invention in which 14 is arranged. When observing an external image, the actual light path is such that the light from the object point in the external environment is the second optical element 13 or another second optical element 14.
And enters the eccentric prism 12 from the second surface 4 or the third surface 5, passes through the first surface 3, and sets the iris position of the observer or the center of rotation of the eyeball as the exit pupil 1 in the observer's eyeball. Projected to

The present invention is shown in FIGS. 1 to 4 and FIGS.
The present invention is not limited to the optical system shown in FIG. 19, but can be applied to other known optical systems.

Among the constituent parameters of the following embodiments, the rotationally symmetric aspherical shape is given by the following equation, where R is the paraxial radius of curvature. The Z axis is the axis of the rotationally symmetric aspherical surface. ^{Z = (h 2 / R)} / [1+ {1- (1 + K) (h 2 / R 2)} 1/2] + Ah 4 + Bh 6 + Ch 8 + Dh 10 ··· (h 2 = x 2 + y 2) · (A) where Z is the amount of deviation from the tangent plane to the origin of the surface shape, K is the conic coefficient, and A, B, C, and D are quartic and 6, respectively.
Next, the 8th and 10th order aspherical coefficients.

The shape of the anamorphic surface is defined by the following equation. A straight line passing through the origin of the surface shape and perpendicular to the optical surface is the axis of the anamorphic surface. As an example, considering up to m = 4 (fourth-order term), it can be expressed by the following equation when expanded.

Z = (CX · x^Two+ CY ・ y^Two) / [1+ ｛1- (1 + K_x) CX^Two・ X^Two − (1 + K_y) CY^Two・ Y^Two｝^1/2 ] R₁｛(1-P₁) X^Two+ (1 + P₁) Y^Two｝^Two R_Two｛(1-P_Two) X^Two+ (1 + P_Two) Y^Two｝^Three R_Three｛(1-P_Three) X^Two+ (1 + P_Three) Y^Two｝^Four R_Four｛(1-P_Four) X^Two+ (1 + P_Four) Y^Two｝^Five ... (b) where Z is the deviation from the tangent plane to the origin of the surface shape
Quantity, CX is curvature in the X-axis direction, CY is curvature in the Y-axis direction, K_xIs
X-axis conical coefficient, K_yIs the Y-axis cone coefficient, R _mIs non
Spherical rotational symmetry component, P_mIs the aspheric term rotationally asymmetric component
is there. In the configuration parameters of the embodiment described later, R_x: Radius of curvature R in the X-axis direction_y: The radius of curvature in the Y-axis direction is used, and between the curvatures CX and CY, R_x= 1 / CX, R_y= 1 / CY.

The shape of the free-form surface is defined by the following equation. The Z axis of the definition is the axis of the free-form surface. As an example, if k = 7 (seventh-order term) is considered, it can be expressed by the following expression when expanded.

Z = C ₂ + C ₃ Y + C ₄ X + C ₅ Y ² + C ₆ YX + C ₇ X ² + C ₈ Y ³ + C ₉ Y ² X + C ₁₀ YX ² + C ₁₁ X ³ + C ₁₂ Y ⁴ + C ₁₃ Y ³ X + C ₁₄ Y ^{2 _{X 2 + C 15 YX 3 +}} C 16 X 4 + C 17 Y 5 + C 18 Y 4 X + C 19 Y 3 X 2 + C 20 Y 2 X 3 + C 21 YX 4 + C 22 X 5 + C 23 Y 6 + C 24 Y 5 X + C 25 Y 4 ^{_{X 2 + C 26 Y 3 X}} 3 + C 27 Y 2 X 4 + C 28 YX 5 + C 29 X 6 + C 30 Y 7 + C 31 Y 6 X + C 32 Y 5 X 2 + C 33 Y 4 X 3 + C 34 Y 3 X 4 + C 35 Y ² X ⁵ + C ₃₆ YX ⁶ + C ₃₇ X ⁷ (c) In the embodiment of the present invention, since the optical system is designed to be symmetric in the X direction, the coefficient of the X odd-number term is set to 0 ( Speaking of the above, C ₄ , C ₆ , C ₉ ‥‥ = 0).

In the constituent parameters described later, the term relating to the aspherical surface for which no data is described is zero. The refractive index for d-line (wavelength 587.56 nm) is shown. The unit of the length is mm.

Y including the optical axis 2 in Examples 1-4 and 5-17
FIGS. 1-4 and FIGS. 5 (b) -17
Shown in The observation angles of view of Examples 1 to 11, 13, and 14 were 30.0 ° for the horizontal angle of view, 22.72 ° for the vertical angle of view, and Example 12
The observation angle of view is 40.0 ° for the horizontal angle of view and 30.5 for the vertical angle of view.
3 °, the observation angle of view in Examples 15 and 16 was 35.
0 °, the vertical angle of view 26.60 °, and the pupil diameter was 4 mm in each of Examples 1 to 16.

The following Examples 1 to 6, 9 to 14, 1
7 shows the configuration parameters and the values of the conditional expressions. Embodiments 7 and 8 are the same as Embodiment 3 and will not be described. In addition, since the configuration parameters at the time of observing the image display elements of Examples 10 and 11 are the same as those of Example 5, the configuration parameters at the time of external observation are shown. The configuration parameters of the twelfth embodiment when observing the image display element are shown as a twelfth example (1), and the configuration parameters at the time of external observation are shown as a twelfth example (2).
In the table, "ASPH" indicates an aspherical surface, "ANAM" indicates an anamorphic surface, "SF" indicates a surface, and "REFL" indicates a reflective surface.

Example 1 Surface Number Curvature Radius Interval Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (pupil) 2 ASPH ∞ 1.5254 56.25 (1ST SF) K 0.0000 Y 18.114 θ 4.44 ° A 0.0000 Z 37.091 B 0.0000 ^{C 1.1599 × 10 -13 D 4.4930 ×} 10 -16 3 ANAM R y -142.541 1.5254 56.25 (2ND SF) R x -122.057 Y 3.041 θ -17.79 ° (REFL) K y -5.4587 Z 52.132 K x -0.2658 R 1 - 5.0900 × 10 ^-10 R ₂ 3.0528 × 10 ^-10 R ₃ 6.2600 × 10 ^-13 R ₄ 4.9434 × 10 ^-15 P ₁ -1.1948 × 10 ⁺¹ P ₂ 2.3791 × 10 ^-1 P ₃ 4.8713 × 10 ^-1 P ₄ ^{3.3074 × 10 -1 4 ASPH ∞ 1.5254} 56.25 (1ST SF) K 0.0000 Y 18.114 θ 4.44 ° (REFL) A 0.0000 Z 37.091 B 0.0000 C 1.1599 × 10 -13 D 4.4930 × 10 -16 5 ∞ 1.5254 56.25 (3RD SF) Y 18.114 θ 4.44 ° (REFL) Z 53.502 6 ANAM R y 47.391 Y 41.220 θ -55.16 ° (4TH SF) R x 86.005 Z 47.787 K y 1.9910 K x -0.1607 R 1 1.1694 × 10 -7 R 2 -2.2052 × 10 ^-10 R ₃ -1.8410 × 10 ^-11 R ₄ -4.2076 × 10 ^-14 P ₁ -6.280 _{4 P 2 -4.0710 P 3 4.2066 ×} 10 -1 P 4 5.1697 × 10 -1 7 ∞ Y 40.079 θ -25.63 ° ( image display _{surface) Z 38.041 (1) θ r3} = 43.85 ° (3) φ t1 ( yz) = 0 (1 / mm) φ _t1 (xz) = 0 (1 / mm).

Example 2 Surface Number Curvature Radius Interval Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (pupil) 2 Free-form surface 1.5000 55.55 (1ST SF) Y 8.738 θ -0.43 ° Z 38.294 3 Free-form surface 1.5000 55.55 (2ND SF) Y 0.000 θ -26.39 ° (REFL) Z 47.232 4 Free-form surface 1.5000 55.55 (1ST SF) Y 8.738 θ -0.43 ° (REFL) Z 38.294 5 Free-form surface 1.5000 55.55 (3RD SF) Y 28.900 θ 4.00 ° REFL) Z 51.503 6 Free-form surface 1.5000 55.55 (4TH SF) Y 37.094 θ -42.91 ° Z 43.146 7 Ｙ Y 39.222 θ -39.45 ° (image display surface) Z 41.032 Free-form surface C ₅ -4.3507 × 10 ^-4 C ₇ -8.3810 _{^{× 10 -3 C 8 -7.2046 × 10}} -5 C 10 -1.6070 × 10 -4 C 12 -5.7849 × 10 -7 C 14 -7.6285 × 10 -7 C 16 2.6344 × 10 -6 C 17 -7.4711 × 10 - ⁹ C ₁₉ -1.9337 × 10 ^-8 C ₂₁ 9.3990 × 10 ^-8 Free-form surface C ₅ -4.4979 × 10 ^-3 C ₇ -8.5757 × 10 ^-3 C ₈ -6.4211 × 10 ^-5 C ₁₀ -3.1176 × 10 ^-5 C ₁₂ 1.3495 × 10 ^-6 C ₁₄ 4.8979 × 10 ^-8 C ₁₆ -2.4 100 × 10 ^-8 C ₁₇ -4.2 204 × 10 ^-8 C ₁₉ -3.82 _{^{12 × 10 -8 C 21 -9.1979 ×}} 10 -9 free curved surface ^{_{C 5 -4.6997 × 10 -4 C 7}} -3.2125 × 10 -3 C 8 -8.6078 × 10 -5 C 10 -1.0181 × 10 -4 C 12 - 2.7246 × 10 ^-6 C ₁₄ 2.7277 × 10 ^-6 C ₁₆ 3.7002 × 10 ^-6 C ₁₇ -3.1103 × 10 ^-8 C ₁₉ 1.0092 × 10 ^-8 C ₂₁ 2.0 208 × 10 ^-7 Free-form surface C ₅ 3.6987 × 10 ^-3 C ₇ 8.3763 × 10 ^-3 C ₈ -8.9771 × 10 ^-4 C ₁₀ 5.0916 × 10 ^-6 C ₁₂ -5.7678 × 10 ^-5 C ₁₄ 4.5123 × 10 ^-7 C ₁₆ -2.3865 × 10 ^-6 (1) θ _r3 = 48.44 ° (3) φ _t1 (yz) = -0.0037 (1 / mm) φ _t1 (xz) = -0.0072 (1 / mm).

Example 3 Surface Number Curvature Radius Interval Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (pupil) 2 ∞ 1.5254 56.25 (1ST SF) Y -27.000 θ 0.00 ° Z 37.395 3 ANAM _Ry -143.929 _{1.5254 56.25 (2ND SF) R x} -123.293 Y -14.868 θ -28.80 ° (REFL) K y 0.3713 Z 42.871 K x -1.9942 R 1 2.1403 × 10 -8 R 2 9.6413 × 10 -13 R 3 6.3684 × 10 -14 R ₄ -1.2452 × 10 ^-17 P ₁ -3.9989 × 10 ^-3 P ₂ -3.0463 P ₃ 2.5677 × 10-1 P ₄ 4.2810 × 10-1 4 ∞ 1.5254 56.25 (1ST SF) Y -27.000 θ 0.00 ° (REFL ) Z 37.395 5 ∞ 1.5254 56.25 (3RD SF) Y 0.079 θ 0.00 ° (REFL) Z 53.539 6 ANAM _Ry 39.861 Y 44.498 θ -66.77 ° (4TH SF) R _x 62.319 Z 51.066 Ky _y 1.5656 K _x 4.2425 R ₁ 3.9064 × 10 ^-6 R ₂ 5.0520 × 10 ^-10 R ₃ 4.9921 × 10 ^-13 R ₄ -6.6158 × 10 ^-15 P ₁ -1.5408 × 10 ^-1 P ₂ 4.0979 P ₃ 1.6631 P ₄ 1.0506 7 Ｙ Y 42.800 θ -21.40 ° (image display surface) Z 38.475 (1) θ _r3 = 44.53 ° (3) φ _t1 ( yz) = 0 (1 / mm) φ _t1 (xz) = 0 (1 / mm).

Example 4 Surface Number Curvature Radius Interval Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (pupil) 2 ANAM R _y -242.348 1.5254 56.25 (1ST SF) R _x -159.768 Y 5.082 θ -3.86 ° _{K y 12.1104 Z 32.396 K x 4.7358} R 1 -2.5719 × 10 -10 R 2 -4.9792 × 10 -12 R 3 8.8695 × 10 -13 R 4 6.7191 × 10 -20 P 1 -1.8150 × 10 +1 P 2 -4.7838 _{P 3 -1.2978 P 4 -7.1284 3 ANAM} R y -119.562 1.5254 56.25 (2ND SF) R x -98.451 Y 27.149 θ -11.26 ° (REFL) K y -0.1186 Z 52.500 K x 0.7866 R 1 -1.6969 × 10 -9 ^{_{R 2 -6.2266 × 10 -11 R 3}} 8.5459 × 10 -16 R 4 8.0998 × 10 -16 P 1 -1.8331 P 2 -4.9789 × 10 -1 P 3 -2.3604 P 4 -9.6450 × 10 -1 4 ANAM R y -242.348 1.5254 56.25 (1ST SF) R x -159.768 Y 5.082 θ -3.86 ° (REFL) K y 12.1104 Z 32.396 K x 4.7358 R 1 -2.5719 × 10 -10 R 2 -4.9792 × 10 -12 R 3 8.8695 × 10 ^-13 R ₄ 6.7191 × 10 ^-20 P ₁ -1.8150 × 10 ⁺¹ P ₂ -4.7838 P ₃ -1.2978 P ₄ -7.1284 5 ANAM R _y -179.00 7 1.5254 56.25 (3RD SF) R x -231.111 Y 27.820 θ 1.74 ° (REFL) K y 2.2288 Z 47.835 K x -72.7188 R 1 6.1912 × 10 -8 R 2 -9.4470 × 10 -13 R 3 2.8064 × 10 -15 ^{_{R 4 2.0069 × 10 -18 P 1}} 2.0705 × 10 -2 P 2 6.7667 P 3 -5.5003 P 4 -4.0534 6 ANAM R y 72.293 Y 42.329 θ -42.24 ° (4TH SF) R x 39.167 Z 43.924 K y -1.0213 K _x -7.8305 R ₁ -7.5404 × 10 ^-7 R ₂ -5.8510 × 10 ^-10 R ₃ 5.8345 × 10 ^-13 R ₄ 1.5291 × 10 ^-15 P ₁ -1.2077 × 10 ^-1 P ₂ 2.1174 × 10 ^-2 P ₃ 2.9220 × 10 ^-1 P ₄ -1.4519 7 ∞ Y 42.878 θ -19.36 ° (image display surface) Z 30.211 (1) θ _r3 = 42.75 ° (3) φ _t1 (yz) = 0.0008 (1 / mm) ) Φ _t1 (xz) = − 0.001 (1 / mm).

Example 5 Surface Number Curvature Radius Interval Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (pupil) 2 -104.851 1.5254 56.25 (1ST SF) Y 2.540 θ -7.02 ° Z 33.527 3 ANAM R _y- 54.751 1.5254 56.25 (2ND SF) R x -62.006 Y -19.747 θ -48.21 ° (REFL) K y -1.3614 Z 30.166 K x 0.1944 R 1 2.4430 × 10 -10 R 2 -1.1189 × 10 -10 R 3 -2.4892 × 10 ^-16 R ₄ 1.9084 × 10 ^-22 P ₁ -2.7674 × 10 ⁺¹ P ₂ 5.3845 × 10 ^-1 P ₃ -4.1468 P ₄ 1.0048 × 10 ⁺¹ 4 -104.851 1.5254 56.25 (1ST SF) Y 2.540 θ -7.02 ° (REFL) Z 33.527 5 ANAM R y -8201.935 1.5254 56.25 (3RD SF) R x 1243.857 Y -37.497 θ 4.95 ° (REFL) K y 0.0000 Z 53.061 K x 0.0000 R 1 9.7227 × 10 -8 R 2 1.2246 × 10 ^-12 R ₃ -1.5956 × 10 ^-16 R ₄ 6.7677 × 10 ^-21 P ₁ 8.5858 × 10 ^-1 P ₂ -4.4664 P ₃ 1.9991 P ₄ 2.2019 6 46.674 Y 28.160 θ -29.19 ° 7 Ｙ Y 31.793 θ
-26.09 ° (image display surface) Z 35.135 (1) θ _r3 = 36.51 °.

Example 6 Surface Number Curvature Radius Interval Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (pupil) 2 ∞ Y 0.000 θ 20.00 ° (virtual surface) Z 0.000 3 ∞ 1.5254 56.25 (1ST SF) ( from the virtual plane) Y 0.000 θ 0.00 ° Z 40.495 4 ANAM R y -146.661 1.5254 56.25 (2ND SF) R x -131.067 ( virtual _{plane) (REFL) K y -0.1158 Y} -23.006 θ -32.35 ° K x -0.6570 Z 49.040 R ₁ 1.4710 × 10 ^-8 R ₂ 2.4181 × 10 ^-10 R ₃ 8.0445 × 10 ^-14 R ₄ -1.0655 × 10 ^-16 P ₁ -6.7968 × 10 ^-1 P ₂ 1.1524 × 10 ^-2 P ₃ 9.6151 × ^{_{10 -1 P 4 5.6260 × 10 -1}} 5 ∞ 1.5254 56.25 (1ST SF) ( virtual plane) (REFL) Y 0.000 θ 0.00 ° Z 40.495 6 ∞ 1.5254 56.25 (3RD SF) ( virtual plane) (REFL) Y 0.000 θ 0.00 ° Z 56.475 7 ANAM R y 70.881 ( virtual _{plane) (4TH SF) R x 99.816} Y 30.811 θ -80.98 ° K y 6.0488 Z 62.245 K x 7.1389 R 1 1.8385 × 10 -5 R 2 1.8499 × 10 - ¹⁰ R ₃ -3.4116 × 10 ^-12 R ₄ -7.2747 × 10 ^-15 P _{13 ^{.2623 × 10 -1 P 2 3.8697 P}} 3 9.0201 × 10 -1 P 4 1.1638 × 10 -1 8 ∞ Y 40.634 θ -2.65 ° ( image display _{surface) Z 30.403 (1) θ r3} = 46.70 ° (3 ) Φ _t1 (yz) = 0 (1 / mm) φ _t1 (xz) = 0 (1 / mm).

Example 9 Surface Number Curvature Radius Interval Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (pupil) 2 ∞ Y 0.000 θ 15.00 ° (virtual surface) Z 0.000 3 -221.433 1.5254 56.25 (1ST SF) (From virtual surface) Y 0.000 θ 0.00 ° Z 38.879 4 -106.803 1.5254 56.25 (2ND SF) (from virtual surface) (REFL) Y -16.310 θ -30.86 ° Z 48.157 5 -221.433 1.5254 56.25 (1ST SF) (virtual surface) From) (REFL) Y 0.000 θ 0.00 ° Z 38.879 6 -208.964 1.5254 56.25 (3RD SF) (from virtual surface) (REFL) Y 0.000 θ 0.00 ° Z 55.417 7 154.685 (from virtual surface) (4TH SF) Y 22.393 θ -20.71 ° Z 41.581 8 ∞ Y 39.534 θ -5.00 ° (image display surface) Z 27.732 (1) θ _r3 = 41.68 ° (3) φ _t1 (yz) = 0.00024 (1 / mm) φ _t1 ( xz) = 0.00024 (1 / mm).

Example 10 Surface Number Curvature Radius Interval Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (pupil) 2 -104.851 1.5254 56.25 (1ST SF) Y 2.540 θ -7.02 ° Z 33.527 3 ANAM R _y- 54.751 Y -19.747 θ -48.21 ° (2ND SF) R x -62.006 Z 30.167 (REFL) K y -1.3614 K x 0.1944 R 1 2.4430 × 10 -10 R 2 -1.1189 × 10 -10 R 3 -2.4892 × 10 - ¹⁶ R ₄ 1.9084 × 10 ^-22 P ₁ -2.7674 × 10 ⁺¹ P ₂ 5.3845 × 10 ^-1 P ₃ -4.1468 P ₄ 1.0048 × 10 ⁺¹ 4 ∞ 2.000 1.4922 57.50 (Fresnel lens first surface) Y 45.000 θ 0.00 ° Z 51.527 5∞ (Fresnel lens second surface) K 0.0000 A 2.0658 × 10 ^-6 B -4.2780 × 10 ^-10 C 3.2196 × 10 ^-14 D 2.1256 × 10 ^-18 .

Example 11 Surface Number Curvature Radius Interval Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (pupil) 2 -104.851 1.5254 56.25 (1ST SF) Y 2.540 θ -7.02 ° Z 33.527 3 ANAM R _y- 54.751 Y -19.747 θ -48.21 ° (2ND SF) R x -62.006 Z 30.166 (REFL) K y -1.3614 K x 0.1944 R 1 2.4430 × 10 -10 R 2 -1.1189 × 10 -10 R 3 -2.4892 × 10 - ¹⁶ R ₄ 1.9084 × 10 ^-22 P ₁ -2.7674 × 10 ⁺¹ P ₂ 5.3845 × 10 ^-1 P ₃ -4.1468 P ₄ 1.0048 × 10 ⁺¹ 4 ∞ 2.000 1.4922 57.50 (Fresnel lens first surface) Y 20.000 θ- 22.00 ° Z 53.527 5 ∞ (Fresnel lens second surface) K 0.0000 A 4.4111 × 10 ^-5 B -1.0534 × 10 ^-7 C 1.1649 × 10 ^-10 D -4.9416 × 10 ^-14 .

Example 12 (1) Surface Number Curvature Radius Interval Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (pupil) 2 Free-form surface 1.5254 56.25 (1ST SF) Y 13.983 θ 9.46 ° Z 33.974 3 Free-form surface 1.5254 56.25 (2ND SF) Y 4.596 θ -15.22 ° (REFL) Z 49.231 4 Free-form surface 1.5254 56.25 (1ST SF) Y 13.983 θ 9.46 ° (REFL) Z 33.974 5 Free-form surface Y 27.094 θ 79.39 ° (3RD SF) Z 35.215 6 ∞ Y 29.266 θ 46.34 ° (image display surface) Z 46.318 Free-form surface C ₅ -2.6152 × 10 ^-3 C ₇ -3.9706 × 10 ^-3 C ₈ -7.5434 × 10 ^-5 C ₁₀ -1.5120 × 10 ^-6 C _{12 ^{2.6572 × 10 -7 C 14 1.3359 ×}} 10 -6 C 16 1.7946 × 10 -7 C 17 -2.9881 × 10 -9 C 19 -3.0362 × 10 -9 C 21 -2.0258 × 10 -7 C 23 -3.8978 × 10 - ¹⁰ C ₂₅ 1.4986 × 10 ^-9 C ₂₇ -3.8974 × 10 ^-9 C ₂₉ -2.5 335 × 10 ^-9 C ₃₀ 4.3 101 × 10 ^-12 C ₃₂ -1.4923 × 10 ^-11 C ₃₄ 7.6026 × 10 ^-11 C ₃₆ -4.2410 × 10 ^-11 Free-form surface C ₅ -6.2524 × 10 ^-3 C ₇ -7.5944 × 10 ^-3 C ₈ -1.0605 × 10 ^-5 C ₁₀ 9.3276 × 10 ^-6 C ₁₂ 8.3882 × 10 ^-7 C ₁₄ -5.6861 × 10 ^-7 C ₁₆ -4.9904 × 10 ^-7 C ₁₇ -2.0403 × 10 ^-10 C ₁₉ -8.0184 × 10 ^-9 C ₂₁ -4.4196 × 10 ^-8 C ₂₃ 4.4149 × 10 ^-10 C ₂₅ 3.8 170 × 10 ^-10 C ₂₇ 8.4970 × 10 ^-11 C ₂₉ -2.8006 × 10 ^-10 C ₃₀ 1.3964 × 10 ^-12 C ₃₂ -1.7677 × 10 ^-10 C ₃₄ 3.3 220 × 10 ^-12 C ₃₆ 6.9401 × 10
⁻¹² free-form surface C ₅ −1.2 118 × 10 ⁻² C ₇ −3.7062 × 10 ⁻³ C ₈ −1.2290 ×
10 ^-4 C ₁₀ 9.9763 × 10 ^-4 C ₁₂ -8.0746 × 10 ^-5 C ₁₄ -3.8939 × 10 ^-5 C ₁₆ 2.6861 × 10 ^-5 C ₁₇ -1.7720 × 10 ^-6 C ₁₉ -3.4243 × 10 ^-6 C ₂₁ -3.5310 × 10 ^-7 C ₂₃ 1.2185 × 10 ^-7 C ₂₅ 1.0019 × 10 ^-7 C ₂₇ 1.4838 × 10 ^-7 C ₂₉ -5.3531 × 10 ^-8 .

Example 12 (2) Surface Number Curvature Radius Interval Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (pupil) 2 Free-form Surface 1.5254 56.25 (1ST SF) Y 13.983 θ 9.46 ° Z 33.974 3 Free-form Surface Y 4.596 θ -15.22 ° (2ND SF) Z 49.231 4 ∞ 2.000 1.4922 57.50 (Fresnel lens first surface) Y 45.982 θ -18.17 ° Z 65.000 5 ∞ (Fresnel lens second surface) K 0.0000 A 3.9372 × 10 ^-6 B -1.6979 × 10 ^-9 C 4.2377 × 10 ^-13 D -4.1829 × 10 ^-17 Free-form surface C ₅ -2.6152 × 10 ^-3 C ₇ -3.9706 × 10 ^-3 C ₈ -7.5434 × 10 ^-5 C ₁₀ -1.5120 × 10 ^-6 C ₁₂ 2.6572 × 10 ^-7 C ₁₄ 1.3359 × 10 ^-6 C ₁₆ 1.7946 × 10 ^-7 C ₁₇ -2.9881 × 10 ^-9 C ₁₉ -3.0362 × 10 ^-9 C ₂₁ -2.0258 × 10 ^-7 C _{23 ^{-3.8978 × 10 -10 C 25 1.4986 ×}} 10 -9 C 27 -3.8974 × 10 -9 C 29 -2.5335 × 10 -9 C 30 4.3101 × 10 -12 C 32 -1.4923 × 10 -11 C 34 7.6026 × 10 - ¹¹ C ₃₆ -4.2 410 × 10 ^-11 Free-form surface C ₅ -6.2524 × 10 ^-3 C ₇ -7.5944 × 10 ^-3 C ₈ -1.0605 × 10 ^-5 C ₁₀ 9.32 76 × 10 ^-6 C ₁₂ 8.3882 × 10 ^-7 C ₁₄ -5.6861 × 10 ^-7 C ₁₆ -4.9904 × 10 ^-7 C ₁₇ -2.0 403 × 10 ^-10 C ₁₉ -8.0184 × 10 ^-9 C ₂₁ -4.4 196 × 10 ^-8 C ₂₃ 4.4 149 × 10 ^-10 C ₂₅ 3.8 170 × 10 ^-10 C ₂₇ 8.4970 × 10 ^-11 C ₂₉ -2.8006 × 10 ^-10 C ₃₀ 1.3 964 × 10 ^-12 C ₃₂ -1.7677 × 10 ^-10 C ₃₄ 3.3 220 × 10 ^-12 C ₃₆ 6.9401 × 10 ^-12 .

Example 13 Surface Number Curvature Radius Interval Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (pupil) 2 Free-Form Surface 1.5163 64.15 (1ST SF) Y 0.000 θ 24.79 ° Z 35.567 3 Free-Form Surface 1.5163 64.15 ( 2ND SF) Y 5.402 θ -9.11 ° (REFL) Z 70.723 4 Free-form surface Y 21.138 θ -25.12 ° (3RD SF) Z 39.783 5 ∞ Y 23.963 θ -11.11 ° (image display surface) Z 34.441 Free-form surface C ₅ 6.8620 × 10 ^-3 C ₇ 7.4 153 × 10 ^-3 C ₈ 5.9417 × 10 ^-5 C ₁₀ 2.9033 × 10 ^-5 C ₁₂ -4.6823 × 10 ^-7 C ₁₄ 3.8 805 × 10 ^-6 C ₁₆ 5.0 284 × 10 ^-7 C ₁₇ 2.3 906 × 10 ^-8 C ₁₉ 7.1030 × 10 ^-8 C ₂₁ 2.8323 × 10 ^-8 Free-form surface C ₅ -3.7101 × 10 ^-3 C ₇ -4.1036 × 10 ^-3 C ₈ 4.2896 × 10 ^-6 C ₁₀ -8.4314 × 10 ^-6 C ₁₂ -8.1477 × 10 ^-8 C ₁₄ 1.1846 × 10 ^-6 C ₁₆ 2.8608 × 10 ^-7 C ₁₇ 8.8 332 × 10 ^-9 C ₁₉ 3.2284 × 10 ^-8 C ₂₁ 1.2745 × 10 ^-8 Free-form surface C ₅ 1.5613 × 10 ^-2 C ₇ 1.5901 × 10 ^-2 C ₈ 3.8223 × 10 ^-4 C ₁₀ -5.9546 × 10 ^-5 C ₁₂ -5.8106 × 10 ^-5 C ₁₄ -4.2859 × 10 ^-5 C ₁₆ -2. 2163 × 10 ^-5 C ₁₇ 1.1940 × 10 ^-6 C ₁₉ 2.0760 × 10 ^-6 C ₂₁ 1.0626 × 10 ^-6 .

Example 14 Surface Number Curvature Radius Interval Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (pupil) 2 Free-Form Surface 1.5163 64.15 (1ST SF) Y -10.123 θ 20.33 ° Z 43.489 3 Free-Form Surface 1.5163 64.15 (2ND SF) Y 1.103 θ -10.31 ° (REFL) Z 65.000 4 Free-form surface Y -10.123 θ 20.33 ° (1ST SF) Z 43.489 5 ∞ Y 17.608 θ -13.99 ° (image display surface) Z 30.846 Free-form surface C ₅ 1.0401 × 10 ^-2 C ₇ 8.6572 × 10 ^-3 C ₈ 9.8267 × 10 ^-5 C ₁₀ 2.0 456 × 10 ^-4 C ₁₂ -9.4226 × 10 ^-6 C ₁₄ 1.6262 × 10 ^-6 C ₁₆ 4.0506 × 10 ^-6 C ₁₇ 3.2669 × 10 ^-7 C ₁₉ 2.1072 × 10 ^-7 C ₂₁ 1.5355 × 10 ^-7 Free-form surface C ₅ -2.5798 × 10 ^-3 C ₇ -3.0708 × 10 ^-3 C ₈ -3.2024 × 10 ^-5 C ₁₀ -3.3909 × 10 ^-6 C ₁₂ 2.9430 × 10 ^-6 C ₁₄ 4.3427 × 10 ^-6 C ₁₆ 3.4981 × 10 ^-6 C ₁₇ -2.8763 × 10 ^-8 C ₁₉ 4.0895 × 10 ^-8 C ₂₁ 5.4666 × 10 ^-8 .

Example 17 Surface Number Curvature Radius Interval Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (pupil) 2 Free-form surface 1.5000 55.55 (1ST SF) Y 18.958 θ 7.69 ° Z 30.730 3 Free-form surface 1.5000 55.55 ( 2ND SF) Y 9.165 θ -13.84 ° (REFL) Z 48.107 4 Free-form surface 1.5000 55.55 (1ST SF) Y 18.958 θ 7.69 ° (REFL) Z 30.730 5 Free-form surface 1.5000 55.55 (2ND SF) Y 9.165 θ -13.84 ° (REFL) ) Z 48.107 6 Free-form surface 1.5000 55.55 (4TH SF) Y 34.128 θ -31.50 ° Z 30.758 7 ∞ Y 47.350 θ -34.92 ° (image display surface) Z 35.893 Free-form surface C ₅ -4.9463 × 10 ^-3 C ₇ -3.4912 × 10 ^-3 C ₈ 6.9477 × 10 ^-5 C ₁₀ 1.7114 × 10 ^-4 C ₁₂ 1.0830 × 10 ^-6 C ₁₄ -2.2541 × 10 ^-7 C ₁₆ 4.5 743 × 10 ^-6 C ₁₇ 6.1581 × 10 ^-8 C ₁₉ 4.7 667 × 10 ^-8 C ₂₁ -1.9359 × 10 ^-7 C ₂₃ -1.3 103 × 10 ^-10 C ₂₅ -7.7572 × 10 ^-10 C ₂₇ 7.0783 × 10 ^-10 C ₂₉ 5.3774 × 10 ^-9 C ₃₀ 4.7726 × 10 ^-12 C ₃₂ 1.3699 × 10 ^-11 C ₃₄ 7.4217 × 10 ^-11 C ₃₆ -1.3460 × 10 ^-10 Free-form surface C ₅ -5.9243 × 10 ^-3 C ₇ -5.4509 × 10 ^-3 C ₈ 3.4016 × 10 ^-5 C ₁₀ 7.9 633 × 10 ^-5 C ₁₂ -4.1470 × 10 ^-7 C ₁₄ 1.0233 × 10 ^-6 C ₁₆ 2.6471 × 10 ^-6 C ₁₇ 2.3016 × 10 ^-9 C ₁₉ 3.3 134 × 10 ^-8 C ₂₁ -1.6456 × 10 ^-8 C ₂₃ -1.3255 × 10 ^-10 C ₂₅ -4.9 215 × 10 ^-10 C ₂₇ -3.3070 × 10 ^-10 C ₂₉ 4.1802 × 10 ^-9 Free-form surface C ₅ 7.9798 × 10 ^-3 C ₇ 1.7546 × 10 ^-2 C ₈ -1.1020 × 10 ^-4 C ₁₀ 9.4392 × 10 ^-4 C ₁₂ -3.9282 × 10 ^-6 C ₁₄ -7.3326 × 10 ^-6 C ₁₆ -1.4273 × 10 ^-5 (1) θ _r3 = 46.48 °.

In the above embodiment, the above defined formula (a)
(B) and (c) are composed of an aspherical surface, an anamorphic surface, and a free-form surface, but are defined as Z defined by the following definition expression (d).
It is also possible to design a surface shape represented by an ernike polynomial and a free-form surface symmetrical in the X direction defined as in the following definition expression (e). In other words, it goes without saying that surfaces of any definition can be used.

As another definitional expression of a plane-symmetric free-form surface, Z
There is an ernike polynomial. The shape of this surface is defined by the following equation (d). The Z axis of the definition is Zerni
It is the axis of the ke polynomial. X = R × cos (A) Y = R × sin (A) Z = D ₂ + D ₃ R cos (A) + D ₄ R sin (A) + D ₅ R ² cos (2A) + D ₆ (R ² -1) + D ₇ ^{R 2 sin (2A) + D} 8 R 3 cos (3A) + D 9 (3R 3 -2R) cos (A) + D 10 (3R 3 -2R) sin (A) + D 11 R 3 sin (3A) + D 12 R 4 _{cos (4A) + D 13 (} 4R 4 -3R 2) cos (2A) + D 14 (6R 4 -6R 2 +1) + D 15 (4R 4 -3R 2) sin (2A) + D 16 R 4 sin (4A) + D 17 ^{R 5 cos (5A) + D} 18 (5R 5 -4R 3) cos (3A) + D 19 (10R 5 -12R 3 + 3R) cos (A) + D 20 (10R 5 -12R 3 + 3R) sin (A) + D 21 ( ^{5R 5 -4R 3) sin (3A} ) + D 22 R 5 sin (5A) + D 23 R 6 cos (6A) + D 24 (6R 6 -5R 4) cos (4A) + D 25 (15R 6 -20R 4 + 6R 2) _{cos (2A) + D 26 (} 20R 6 -30R 4 + 12R 2 -1) + D 27 (15R 6 -20R 4 + 6R 2) sin (2A) + D 28 (6R 6 −5R ⁴ ) sin (4A) + D ₂₉ R ⁶ sin (6A) (D) 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 free-form surface symmetrical in the X direction can be obtained by the above (c)
It can be defined as follows corresponding to the expression. _{Z = C 2 + C 3 Y} + C 4 | X | + C 5 Y 2 + C 6 Y | X | + C 7 X 2 + C 8 Y 3 + C 9 Y 2 | X | + C 10 YX 2 + C 11 | X 3 | + C 12 Y 4 ^{_{+ C 13 Y 3 | X |}} + C 14 Y 2 X 2 + C 15 Y | X 3 | + C 16 X 4 + C 17 Y 5 + C 18 Y 4 | X | + C 19 Y 3 X 2 + C 20 Y 2 | X 3 | + C ^{_{21 YX 4 + C 22 | X}} 5 | + C 23 Y 6 + C 24 Y 5 | X | + C 25 Y 4 X 2 + C 26 Y 3 | X 3 | + C 27 Y 2 X 4 + C 28 Y | X 5 | + C 29 X ^{_{6 + C 30 Y 7 + C}} 31 Y 6 | X | + C 32 Y 5 X 2 + C 33 Y 4 | X 3 | + C 34 Y 3 X 4 + C 35 Y 2 | X 5 | + C 36 YX 6 + C 37 | X 7 | (E) By the way, one set including the eyepiece optical system and the image display element as described above is prepared and configured for one eye mounting. Prepare a pair of left and right It may be configured for binocular mounting by supporting it at a distance. In this way, it can be configured as a stationary or portable image display device that can be observed with one eye or both eyes.

FIG. 21 (in this case, attachment to the left eye) shows a state where the camera is mounted on one eye, and FIG. 22 shows a state where the camera is mounted on both eyes. FIG.
In FIG. 22, reference numeral 31 denotes a display device main body. In FIG. 21, a support member is held in front of the left eye of the observer's face, and in FIG. 22, it is held in front of both eyes of the observer's face. Is fixed through the head. One end of the support member is joined to the display device main body 31, the left and right front frames 32 extending from the temple of the observer to the upper part of the ear, and the other end of the front frame 32 is joined to the side of the observer. From both the left and right rear frames 33 extending across the head (in the case of FIG. 21), or further, one end of each is joined one by one so as to be sandwiched between the other ends of the left and right rear frames 33, and observed. (In the case of FIG. 22).

In the vicinity of the joint of the front frame 32 with the rear frame 33, a rear plate 35 made of an elastic body and made of, for example, a metal plate spring is joined. The rear plate 35 is joined so that the rear cover 36, which carries one wing of the support member, is positioned behind the ear at a portion where the back cover of the observer is attached to the neck of the observer and can be supported (see FIG. 22). Case). A speaker 39 is mounted in the rear plate 35 or the rear cover 36 at a position corresponding to the ear of the observer.

A cable 41 for transmitting video / audio signals and the like from the outside is transmitted from the display device main body 31 through the top frame 34 (in the case of FIG. 22), the rear frame 33, the front frame 32, and the rear plate 35. Rear plate 3
5 or the rear cover 36 projects outward from the rear end. The cable 41 is connected to the video playback device 40.
It is connected to the. In the figure, reference numeral 40a denotes a switch and a volume adjusting unit of the video reproducing device 40.

The cable 41 may be jacked at the end 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. In addition, an antenna may be connected to receive an external signal by radio wave in order to reject an obstructive code.

Further, when the eyepiece optical system of the image display apparatus of the present invention is used as an imaging optical system, for example, a compact optical system Ob and a finder optical system Fi as shown in FIG. It can be used for the finder optical system Fi of the camera Ca. FIG. 24 shows a configuration diagram of an optical system when used as an imaging optical system. An objective optical system Lt can be configured by the front lens group GF, the aperture stop D, and the eyepiece optical system DS of the present invention disposed behind the aperture stop D. The image formed by the objective optical system Lt is erected by a four-time reflecting Porro prism P provided on the observer side of the objective system Lt, and can be observed by an eyepiece Oc.

Although the prism optical element, image observation device, and image display device of the present invention have been described based on several embodiments, the present invention is not limited thereto, and various modifications are possible. Any configuration may be made within the scope of the invention.

The above-described prism optical element and image observation apparatus of the present invention can be constituted, for example, as follows. [1] In a prism optical element formed by a plurality of surfaces sandwiching a medium having a refractive index (n) larger than 1 (n> 1), the prism optical element causes light rays to enter the prism optical element. Alternatively, a first surface having a combination of a transmitting action for emitting light rays from inside the prism optical element and an internal reflecting action inside the prism optical element, and the first face facing the first medium with the medium interposed therebetween. And a second surface having an internal reflection action inside the prism optical element, and disposed at a position substantially close to the second surface and opposed to the first surface with the medium interposed therebetween, inside the prism optical element. A third surface having an internal reflection action of
When the first surface has a function of causing light rays to enter the inside of the prism optical element, the first surface has a function of emitting light rays from the inside of the prism optical element, and the first surface emits light rays from the inside of the prism optical element. Having a fourth surface having a transmitting action such that a light ray enters the inside of the prism optical element, the refractive index at the d-line of the medium is n _d , and the arbitrary refractive index at the third face is n when the angle of internal reflection of light rays and theta _r3, the prism optical element and satisfies the _{^{sin -1 (1 / n d)}} ≦ θ r3 ≦ 60 ° ··· (1).

[0142] [2] In _{^{[1], sin -1 (1 / n d}} ) ≦ θ r3 ≦ 50 ° ··· prism optical element and satisfies the (2).

[3] In the above [1] or [2],
A prism optical element, wherein the reflection of the first surface is total reflection.

[4] Any one of the above [1] to [3]
9. The prism optical element according to item 1, wherein a refractive index (n) of a medium of the prism optical element is larger than 1.3 (n> 1.3).

[5] Any one of the above [1] to [3]
3. The prism optical element according to claim 1, wherein at least one surface constituting the prism optical element is flat.

[6] Any one of the above [1] to [5]
9. The observation optical system according to item 1, wherein the prism optical element is disposed inside the observation optical system.

[7] The observation optical system according to the above [6], wherein the prism optical element is disposed inside the objective lens.

[8] In the above item [6], the prism optical element is arranged behind the objective lens, and is arranged inside the image erecting means having the function of erecting the object image formed by the objective lens. A camera finder optical system, characterized in that:

[0149]

[9] The camera finder optical system according to [8], wherein the prism optical element has an eyepiece function as well as an image erecting function.

[10] In any one of the above items [1] to [5], the image forming means may be arranged so as to face the fourth surface of the prism optical element, and the prism optical element and the image forming means may be arranged as follows. A holding member having a function of holding the image on the observer's face, and a light beam emitted from the image forming means is incident on the fourth surface in the order of the optical path inside the prism optical element, and is incident on the third surface. Reflected, reflected at the first surface,
A head-mounted image display device, wherein the light is reflected by the second surface and emitted from the first surface.

[11] In an image observation apparatus having an image forming means and an eyepiece optical system having an action of guiding an image formed by the image forming means to an observation eyeball, the eyepiece optical system has a refractive index between them. (N) is greater than 1 (n> 1), the prism member having a surface configuration having at least three surfaces filled with a single medium, and the prism member is configured to at least emit a light beam emitted from the image forming means. It has a function of internally reflecting three times, and at least two of the at least three internal reflections are configured to be reflections by a total reflection, and the at least two total reflections are performed. At least one reflection in the reflection action is performed by a surface of the single element medium of the prism member which is arranged on the viewer side, and the surface is generated by internal reflection of the prism member. The at least two surfaces are formed of the single medium so as to be formed into a curved surface having a function of correcting aberrations, and that the external world can be observed through at least two of the at least three surfaces of the prism member. An image observation apparatus characterized by being arranged so as to reduce distortion generated when observing the outside world with the interposition therebetween.

[12] In an image observation apparatus having an image forming means and an eyepiece optical system having an action of guiding an image formed by the image forming means to an observation eyeball, the eyepiece optical system includes at least a prism member. The prism member has at least four optically active surfaces having a transmission or reflection optical effect in its surface configuration, and has a refractive index (n) between the four optically active surfaces. Are embedded in a single medium (n> 1) larger than 1; the four optically active surfaces have a transmitting effect and a reflecting effect and are arranged on a viewer's eyeball side; A second surface having a reflection function that is disposed to face one surface with the medium interposed therebetween and that is disposed at least eccentric or inclined with respect to the observer's visual axis;
A first surface, a third surface having a reflective action disposed opposite to the first surface with the medium interposed therebetween, and disposed substantially adjacent to the second surface, and having one end substantially adjacent to the first surface. And a fourth surface disposed so that the other end is substantially close to the third surface. At least the third surface is configured so that the third surface has a total reflection effect, and The first surface, the simple substance medium, and the third surface are configured to have an external observation function of observing the external world through one surface, the simple substance medium, and the third surface. Image observation device.

[13] In the above item [12], it is preferable that the image forming means is an image display element in which an image forming screen is arranged to face the fourth surface, and the second surface is formed by a curved surface. Characteristic image observation device.

[14] In the above item [13], there is provided a holding member having a function of holding the image display element and the eyepiece optical system in front of an observer's eyeball, and the prism member has
A light beam emitted from the image display element enters from the fourth surface, the incident light beam is reflected by the third surface, the reflected light beam is reflected by the first surface, and the reflected light beam is reflected by the second surface. And a reflected light beam is emitted from the first surface.

[15] In any one of the above items [12] to [14], in the external observation function, the combined power in at least a part of the first surface and the third surface is substantially zero. An image observation apparatus characterized by being formed as described above.

[16] An image observation apparatus according to any one of [12] to [15], wherein the first surface and the third surface are formed as curved surfaces.

[17] An image observation apparatus according to any one of [12] to [16], wherein the first surface and the third surface are formed as spherical surfaces.

[18] The image observation apparatus according to any one of [12] to [14], wherein the first surface and the third surface are formed as flat surfaces.

[0159] [19] In any one of [18] to the [12], to the synthesis of power at any location between the said first surface a third surface and phi _t1, -0.5 ≦ φ _t1 ≦ 0.5 (1 / mm) (3)

[20] In any one of the above items [12] to [19], the prism member may be used for observation of an image formed by the image forming means and observation of the external image. An image observation device characterized in that the image observation device is also formed so as to be fixed at the same position.

[21] The image observation apparatus according to the above [20], wherein an image from the image forming means and an external image can be observed for each partial area through the first surface and the third surface.

[22] In any one of the above items [12] to [19], the prism member has a switching means for switching between observation of an image formed by the image forming means and observation of the external image. The switching means is formed to have a function of moving the prism member.

[23] In the above item [22], the switching means may be configured such that an optical path from the prism member to an observer's eyeball when observing the image formed by the image forming means observes and observes the external image. An image observation apparatus characterized in that the prism member is moved so as to substantially coincide with an optical path from the prism member to an observer's eyeball when performing the operation.

[24] In the above item [22] or [23], the switching means is configured to move the prism member so as to be movable in a direction along a plane including an optical path of an axial principal ray. An image observation apparatus, characterized in that:

[25] In the above item [22] or [23], the switching means is configured to move the prism member so as to be movable in a direction perpendicular to a visual axis of an observer. Image observation device.

[26] The image observation apparatus according to the above [22] or [23], wherein the switching means moves the prism member so as to be rotatable.

[27] In an image observation apparatus having an image forming means and an eyepiece optical system having an effect of guiding an image formed by the image forming means to an observation eyeball, the eyepiece optical system includes at least a prism member. The prism member has at least four optically active surfaces having a transmission or reflection optical effect in its surface configuration, and has a refractive index (n) between the four optically active surfaces. Are embedded in a single medium larger than 1 (n> 1), the four optically active surfaces have a transmitting effect and a reflecting effect, and are disposed on the observer's eyeball side; A second surface having a reflection function that is disposed to face one surface with the medium interposed therebetween and that is disposed at least eccentric or inclined with respect to the observer's visual axis;
A first surface, a third surface having a reflective action disposed opposite to the first surface with the medium interposed therebetween, and disposed substantially adjacent to the second surface, and having one end substantially adjacent to the first surface. And a fourth surface arranged so that the other end is substantially close to the third surface. The prism member is configured such that at least the second surface or the third surface has a total reflection effect. Wherein an eye-gaze detecting means having an operation of detecting an observer's eye-gaze is arranged near an area of the second surface or the third surface having the total-reflection effect where the total-reflection effect is generated. Observation device.

[28] The image observation apparatus according to the above [27], wherein the prism member is configured so that the first surface has a total reflection effect.

[29] In the above [28], it is preferable that the line-of-sight detecting means is disposed at a position where the line-of-sight detecting means passes through the total reflection area of the second surface or the third surface and detects the line of sight of the observer. Characteristic image observation device.

[30] The image observation apparatus according to any one of [27] to [29], further comprising an illuminating means for illuminating the observer's eyeball.

[31] The image observation apparatus according to the above [30], wherein the illumination means uses infrared light.

[32] The head according to [31], further comprising a holding member having an action of holding the eyepiece optical system, the image forming means, and the visual line detecting means on the face of the observer. Part-mounted image display device.

[33] In any one of the above items [10], [14] to [26], [32], positioning means for positioning the image forming means and the eyepiece optical system with respect to the observer's head. An image observation device, comprising:

[34] In any one of the above items [10] and [14] to [26], [32] and [33],
An image observation apparatus, comprising: support means for supporting at least two sets of the image observation apparatus at a constant interval.

[35] The above [1] to [10] and [2]
7] In any one of the items [34] to [34], the second surface and the third surface optically act as separate surfaces, and are structurally formed by one surface. A prism optical element or a prism member.

[36] In the above item [35], in one of the surfaces constituting the second surface and the third surface, a region near the fourth surface acts as a third surface, and A prism optical element or a prism member, wherein a far region is configured to act as a second surface.

[37] In the above item [36], one of the surfaces constituting the second surface and the third surface is such that the central region also serves as both the second surface and the third surface. A prism optical element or a prism member.

[0178]

As is apparent from the above description, according to the present invention, an image which provides a clear observation image even in a very thin and small eyepiece optical system, has a small amount of unnecessary light, and a wide observation angle of view. An image display device as an observation device can be provided.

[Brief description of the drawings]

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

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

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

FIG. 4 is a sectional view of a monocular optical system of a head mounted image display device using an eyepiece optical system according to a fourth embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a monocular optical system of a head-mounted image display device using an eyepiece optical system according to a fifth embodiment of the present invention (b), in comparison with a modified example (a).

FIG. 6 is a cross-sectional view of a monocular optical system of a head mounted image display device using an eyepiece optical system according to a sixth embodiment of the present invention.

FIG. 7 is a sectional view of a monocular optical system of a head mounted image display device using an eyepiece optical system according to a seventh embodiment of the present invention.

FIG. 8 is a cross-sectional view of a monocular optical system of a head mounted image display device using an eyepiece optical system according to Example 8 of the present invention.

FIG. 9 is a sectional view of a monocular optical system of a head mounted image display device using an eyepiece optical system according to a ninth embodiment of the present invention.

FIG. 10 is a sectional view of a monocular optical system of a head mounted image display apparatus using an eyepiece optical system according to a tenth embodiment of the present invention.

FIG. 11 is a sectional view of a monocular optical system of a head mounted image display device using an eyepiece optical system according to an eleventh embodiment of the present invention.

FIG. 12 is a cross-sectional view of a monocular optical system of a head mounted image display device using an eyepiece optical system according to a twelfth embodiment of the present invention.

FIG. 13 is a cross-sectional view of a monocular optical system of a head mounted image display device using an eyepiece optical system according to a thirteenth embodiment of the present invention.

FIG. 14 is a sectional view of a monocular optical system of a head mounted image display device using an eyepiece optical system according to a fourteenth embodiment of the present invention.

FIG. 15 is a sectional view of a monocular optical system of a head mounted image display device using an eyepiece optical system according to Embodiment 15 of the present invention.

FIG. 16 is a sectional view of a monocular optical system of a head mounted image display device using an eyepiece optical system according to Embodiment 16 of the present invention.

FIG. 17 is a cross-sectional view of a monocular optical system of a head mounted image display device using an eyepiece optical system according to a seventeenth embodiment of the present invention.

FIG. 18 is a cross-sectional view of a case where a line-of-sight detection unit is provided in the eyepiece optical system as in the seventeenth embodiment.

FIG. 19 is a diagram illustrating a moving direction and a mechanism when the eyepiece optical system as in Embodiment 17 is converted from an electronic image observation position to an external image observation position.

FIG. 20 is a view for explaining an operation of removing unnecessary light by a total reflection surface in the present invention.

FIG. 21 is a diagram illustrating a state in which the image display device of the present invention is configured to be mounted on one eye.

FIG. 22 is a diagram illustrating a state in which the image display device of the present invention is configured to be mounted on both eyes.

FIG. 23 is a configuration diagram when an optical system according to the present invention is used as an imaging optical system.

FIG. 24 is a configuration diagram of an optical system when the optical system according to the present invention is used as an imaging optical system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Exit pupil position (observer pupil position) 2 ... Observer's visual axis (axial principal ray) 3 ... First surface of eyepiece optical system 4 ... Second surface of eyepiece optical system 5 ... Third surface of eyepiece optical system 6 Fourth surface of eyepiece optical system 7 Image display element 8 Fresnel lens 9 Line of sight detection optical system 10 Line of sight detector 11 Illumination means 12 Eyepiece optical system (eccentric prism) 13, 14 Second optical element DESCRIPTION OF SYMBOLS 15 ... Eyeball of observer 16 ... Optical filter 17 ... Linear motor 18 ... Projection part provided in the optical element 19 ... Guide (rail) provided in the exterior part 31 ... Display main body part 32 ... Front frame 33 ... Rear frame 34 ... top frame 35 ... rear plate 36 ... rear cover 39 ... speaker 40 ... video playback device 40a ... switch and volume adjustment unit 41 ... cable NC ... coating hole Ob ... shooting optical system Fi ... Zehnder optical system Ca ... compact camera GF ... front lens group D ... aperture stop DS ... eyepiece optical system (the present invention) Lt ... objective optical system P ... Porro prism Oc ... eyepiece

Claims (4)

[Claims] 1. The refractive index (n) is larger than 1 (n> 1).
1) A prism optical element formed by a plurality of surfaces sandwiching a medium, wherein the prism optical element causes a light ray to enter the prism optical element or emits a light ray from the prism optical element. And a first surface having a combination of an internal reflection function inside the prism optical element and a second surface having an internal reflection function inside the prism optical element which is disposed opposite to the first surface with the medium interposed therebetween. A third surface disposed at a position substantially close to the second surface and opposed to the first surface with the medium interposed therebetween and having an internal reflection action inside the prism optical element;
When the surface has the function of emitting light from inside the prism optical element when the surface has the function of causing light to enter the prism optical element, and when the first surface has the function of emitting light from the inside of the prism optical element, A fourth surface having a transmissive action such that a light ray is incident on the inside of the prism optical element, the refractive index of the medium at d-line is n _d , and the inside of any light ray on the third face is when the angle of reflection and theta _r3, the prism optical element and satisfies the _{^{sin -1 (1 / n d)}} ≦ θ r3 ≦ 60 ° ··· (1). 2. An image observation apparatus comprising: an image forming unit; and an eyepiece optical system having an action of guiding an image formed by the image forming unit to an observation eyeball, wherein the eyepiece optical system has a refractive index ( n) is greater than 1 (n> 1), the prism member having a surface configuration having at least three surfaces filled with a single medium, and the prism member is configured to emit at least three rays emitted from the image forming means. And at least two of the at least three internal reflections are reflected by the total reflection, and the at least two total reflections are performed. At least one reflection in the action is performed by a surface of the prism member disposed on the observer side of the unitary medium, and the surface causes aberration caused by internal reflection of the prism member. The at least two surfaces sandwich the unitary medium so that external observation can be performed through at least two of the at least three surfaces of the prism member. An image observation apparatus characterized by being arranged so as to reduce distortion generated when observing the outside world. 3. An image observation apparatus comprising: an image forming unit; and an eyepiece optical system having an action of guiding an image formed by the image forming unit to an observation eyeball, wherein the eyepiece optical system includes at least a prism member, The prism member is provided with at least four optically active surfaces having a transmission or reflection optical effect in its surface configuration, and has a refractive index (n) between the four optically active surfaces. The four optically active surfaces have a transmitting effect and a reflecting effect and are arranged on the observer's eyeball side, and the first optical operating surface is configured to be embedded in a single medium (n> 1) larger than 1 (n> 1). A second surface having a reflection function, which is disposed to face a surface with the medium interposed therebetween and is disposed at least eccentric or inclined with respect to the observer's visual axis, and faces the first surface with the medium interposed therebetween; Disposed and substantially adjacent to the second surface A third surface having a reflection action disposed, and a fourth surface disposed such that one end is substantially adjacent to the first surface and the other end is substantially close to the third surface, and The prism member is configured such that the third surface has a total reflection effect, and has an external observation effect that allows an external world to be observed through the first surface, the simple substance medium, and the third surface. An image observation apparatus comprising the first surface, the simple substance medium, and the third surface as described above. 4. An image observation apparatus comprising: an image forming unit; and an eyepiece optical system having an operation of guiding an image formed by the image forming unit to an observation eyeball, wherein the eyepiece optical system includes at least a prism member, The prism member is provided with at least four optically active surfaces having a transmission or reflection optical effect in its surface configuration, and has a refractive index (n) between the four optically active surfaces. The four optically active surfaces have a transmitting effect and a reflecting effect and are arranged on the observer's eyeball side, and the first optical operating surface is configured to be embedded in a single medium (n> 1) larger than 1 (n> 1). A second surface having a reflection function, which is disposed to face a surface with the medium interposed therebetween and is disposed at least eccentric or inclined with respect to the observer's visual axis, and faces the first surface with the medium interposed therebetween; Disposed and substantially adjacent to the second surface A third surface having a reflection action disposed, and a fourth surface disposed such that one end is substantially adjacent to the first surface and the other end is substantially close to the third surface, and The prism member is configured such that the second surface or the third surface has a total reflection effect,
An image observation apparatus, wherein a line-of-sight detecting means having an operation of detecting an observer's line of sight is arranged near an area of the second surface or the third surface having the total reflection effect where the total reflection effect is generated.