JP2003149591A - Display optical system, image display unit, and optical system and device for imaging - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a display optical system and imaging optical system have a wide angle of view by increasing the power of the optical system to constitute the display optical system or imaging optical system by using a small-sized image display element. SOLUTION: The display optical system which guides light from an original picture 10 to the eye of an observer or a projected surface is provided with a 1st optical system 30 having a 1st surface 31b, a 2nd surface 31C which reflects a center view angle main light beam made incident on the 1st surface again so that the light beam travels to the opposite side from the last time about the normal of the surface at its hit point, and a 3rd surface 31a which transmits light traveling from the original picture to the 1st surface and reflects the light returned from the 2nd surface to the 1st surface and then reflected to guide the light to the eye of the observer or the projected surface and a 2nd optical element 20 which guides the light from the original picture to the 3rd surface; and an air gap is provided between the 3rd surface and the projection surface of the 2nd optical system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display optical system suitable for an image display device such as a head mounted display or a projector for enlarging and displaying an original image displayed on an image display device or the like, and an imaging optical system suitable for the image pickup device. It is a thing.

[0002]

2. Description of the Related Art A head-mounted image display device (head-mounted display) which uses an image display device such as a CRT or LCD and enlarges an image displayed on the display device through an optical system is well known. Has been.

In the image display device such as the head mounted display, since these devices are mounted on the head, it is particularly required to reduce the size and weight of the entire device. Further, in consideration of weight balance, appearance and the like, it is preferable that the thickness is thin in the visual axis direction of the observer. Further, in order to give a powerful effect to the displayed enlarged image, a magnified image as large as possible is desired.

FIG. 15 shows an image display device using a conventional coaxial concave mirror. In the device, the display element 101
The light flux from the image displayed on the half mirror 102 is reflected by the half mirror 102 to enter the concave mirror 103, and the light flux reflected by the concave mirror 103 is guided to the eye E of the observer through the half mirror 102. The image displayed on the display element 101 is formed as a virtual image enlarged by the concave mirror 103. Thereby, the observer can observe the enlarged virtual image of the image displayed on the display element 101.

Further, for example, JP-A-7-333551, JP-A-8-50256, and JP-A-8-1603.
No. 40 and Japanese Patent Laid-Open No. 8-179238, an LCD as an image display element for displaying an image is disclosed.
There has been proposed an image display device that uses a (liquid crystal) and a thin prism as an observation optical system to reduce the thickness of the entire device.

FIG. 16 shows an image display device proposed in Japanese Patent Laid-Open No. 7-333551. In this device, the light emitted from the LCD 111 is incident on the incident surface 113 of the small decentering prism 112. Then, the total reflection surface 1 having a curvature formed on the prism 112.
The light flux is folded between the reflecting surface 115 and the reflecting surface 115, and then emitted from the eccentric prism 112 from the surface 114 and guided to the eye E of the observer. This enables the display device (LCD)
A virtual image of the image displayed on 111 is formed, and an observer observes this virtual image.

The reflecting surface 115 of the decentering prism 112 is composed of a decentered free-form surface composed of a decentered non-rotationally symmetric surface (a surface having a different optical power depending on the azimuth angle, a so-called free-form surface).

The type of optical system shown in FIG. 16 is characterized in that it is easier to make the entire apparatus thinner and to widen the angle of view of the observation field, as compared with the type using the conventional coaxial concave mirror shown in FIG. Have

[0009]

In recent years, LCDs, which are display elements for displaying images, have been made finer, and LCDs having the same number of pixels as the conventional ones but smaller in size than the conventional ones.
Etc. have been developed. Using such a downsized image display element is advantageous for downsizing the device,
In order to achieve the same angle of view as the conventional one, it is necessary to increase the magnification of the optical system.

In view of such a situation, Japanese Patent Laid-Open No. 10-1
Japanese Patent Laid-Open No. 53748 proposes an optical system in which a decentered prism and a relay lens system are combined and an intermediate image is once formed by the relay lens system and then an image displayed on a display element is guided to an observer. As a result, while having the characteristic of a thin type of the type shown in FIG. 16, the magnification is further improved and the angle of view is widened with respect to the LCD size.

Further, in order to further improve the optical performance as compared with the optical system proposed in Japanese Patent Laid-Open No. 10-153748, the internal reflection surface of the decentering prism is increased so that the intermediate image is formed only by the decentering prism. A type in which a second decentering prism is provided in the first decentering prism optical system, and the like in which the image is formed and the image is guided to an observer are disclosed in JP-A-2000-06.
6106, Japanese Patent Laid-Open No. 2000-105338,
JP 2000-131614 A, JP 2000-1
It is proposed in Japanese Patent Laid-Open No. 99853/2000, Japanese Patent Laid-Open No. 2000-227554 and Japanese Patent Laid-Open No. 2000-231060.

Generally, an optical system of the type that temporarily forms an intermediate image has a problem that the optical path length becomes long and the size of the apparatus becomes large. And using a dual-purpose surface that fulfills the reflection function,
We are aiming for miniaturization by devising ways such as intersecting the optical paths.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a display optical system that can achieve a wide display angle of view while using a small-sized display element, and a compact display optical system as a whole, and a compact image pickup optical system that can achieve a wide shooting angle of view. I am trying.

[0014]

In order to achieve the above-mentioned object, in the first invention of the present application, in the display optical system for guiding the light from the original image to the observer's eye or the projected surface, at least 3
A first optical system having two surfaces is provided, and the first optical system reflects at least a first surface having a reflecting action, and the light reflected by the first surface is reflected again toward the first surface. The light from the second surface and the original image is transmitted and made incident on the first optical system, and the light reflected from the second surface and returned to the first surface is reflected to the observer's eye or the projection surface. A second optical system which has a third surface for guiding and which guides light from the original image to the third surface is provided, and an air gap is provided between the third surface and the exit surface of the second optical system. The central angle-of-view principal ray that is re-incident on the first surface is reflected and travels to the opposite side to the normal of the surface on the hit point.

That is, in the first optical system, the first,
By making the light path substantially reciprocate between the second and third surfaces and returning the light path, it is possible to secure a long light path length in spite of the small optical system. Therefore, it is possible to achieve a wide display angle of view while using a small original image (an image displayed on the image display element or the like), and it is possible to reduce the size of the entire display optical system including the second optical system. .

By providing an air gap between the third surface of the first optical system and the exit surface of the second optical system,
Since a large number of optical surfaces can be secured and the degree of freedom in optical design can be increased, it is possible to improve the optical performance of the display optical system and further downsize it.

Incidentally, it is preferable to form an intermediate image of light in the display optical system (for example, a transparent body). That is, by adopting an intermediate image-forming type in which the intermediate image-forming surface of a small original image is enlarged and displayed, the degree of freedom in layout is increased, the original image can be displayed on a large screen, and the optical path length is considerably long. However, the display optical system can be made compact.

Further, by making the optical surfaces constituting the first optical system and the second optical system eccentric with respect to the incident light, it is possible to achieve further thinning and to give the optical surfaces a curvature. This makes it possible to eliminate unnecessary surfaces in the display optical system and achieve miniaturization. Furthermore, by making the optical surface a rotationally asymmetric surface (free-form surface), various aberrations can be corrected well, and if multiple rotational asymmetric surfaces (free-form surface) are adopted, the aspect ratio of the original image and the aspect ratio of the display image can be improved. It is possible to make them close to each other, and it is possible to obtain a high-quality display image.

The display optical system is a projection type image display device for enlarging and projecting an image on a projection surface such as a head mounted display (HMD) or a screen for an observer to wear on the head to observe the image. It is suitable for image display devices such as (projectors).

In the second invention of the present application, the imaging optical system for guiding the light from the subject to the imaging surface has a first optical system having at least three surfaces, and the first optical system is at least The first surface having a reflecting action, the second surface that reflects the light reflected by the first surface toward the first surface again, and the light that has entered the first optical system from the subject and A first optical system having a third surface for transmitting the light reflected back from the second surface to the first surface to the imaging surface side; and a second optical system for guiding the light emitted from the third surface to the imaging surface Optical system is provided, and the third surface and the incident surface of the second optical system are arranged with an air gap, and the central angle-of-view chief ray incident on the first surface again is on the hit point. With respect to the normal of the surface of, it is reflected on the side opposite to the previous time and proceeds.

That is, in the first optical system, the first,
By making light reciprocate between the second and third surfaces to fold the optical path, it is possible to secure a long optical path length even with a small optical system. Therefore, it is possible to achieve a wide shooting angle of view while the size of the entire imaging optical system including the second optical system is small.

Then, by providing an air gap between the third surface of the first optical system and the incident surface of the second optical system,
Since a large number of optical surfaces can be secured and the degree of freedom in optical design can be increased, it is possible to improve the optical performance of the image pickup optical system and further downsize it.

Incidentally, it is preferable to form an intermediate image of light in the image pickup optical system (for example, a transparent body). That is, by adopting an intermediate image formation type in which the intermediate image formation surface of the subject is reduced and guided to the image pickup surface, the degree of freedom in layout is increased, and it is possible to sufficiently reduce the object image having a wide angle of view and lead it to the image pickup surface. In addition, the image pickup optical system can be made compact even if the optical path length is considerably lengthened.

Further, by decentering the optical surface constituting the image pickup optical system with respect to the light, it is possible to further reduce the thickness, and by giving the optical surface a curvature, an unnecessary surface in the image pickup optical system. It is possible to eliminate the above and reduce the size. Furthermore, by making the optical surface a rotationally asymmetrical surface (free-form surface), various aberrations can be corrected well, and if multiple rotationally asymmetrical surfaces (free-form surface) are adopted, the aspect ratio of the subject and the aspect ratio of the captured image can be improved. It is possible to make them close to each other, and it is possible to obtain a high-quality photographed image.

The image pickup optical system is suitable for an image pickup apparatus such as a digital still camera or a video camera.

Further, in the first and second inventions, an optical surface is formed on the transparent body, and light is totally reflected by any one of the optical surfaces, so that the light quantity loss is reduced even with a long optical path length. It is possible.

In any of the display optical system and the image pickup optical system, it is preferable that the surface that reflects and returns light is a curved surface. If the folding reflection surface is a flat surface, the directions of the light rays of the peripheral image cannot be individually controlled at the time of reflection, so that the optical system becomes large. If the folding reflection surface is a rotationally asymmetric surface, the light ray direction of the peripheral image can be freely controlled, and therefore the size can be further reduced as compared with the case of a curved surface.

Further, the size of the display optical system and the image pickup optical system is influenced by forming the second surface (folded reflection surface) as a reflecting member different from the optical element having the first and second surfaces. Since the number of effective surfaces in the optical path can be increased without giving them, it is possible to increase the degree of freedom in design and improve the optical performance.

Further, by forming the reflecting member as a rear surface mirror having a transmitting surface and a reflecting surface, the transmitting surface can also be used as an optical surface, so that the imaging performance can be further improved without affecting the size of the optical system. You can

Further, by making the first optical system and the second optical system have positive power, it is possible to disperse the positive power in the entire optical system, so that aberration correction is facilitated and imaging performance is improved. Can be improved.

The above optical system, in other words, the first optical system
Angle with respect to the normal to the hit point of the central angle of view chief ray that first entered the surface of, and the normal to the hit point of the central angle of view chief ray that is reflected by the second surface and re-enters the first surface The reflection angle with respect to is the opposite sign. That is, the light reflected from the first surface
The surface of the first surface reflects the light so that it returns to the first light reflection area side (reflection area, near the reflection area, or near the reflection area), thereby effectively overlapping the light paths and reducing the long light path length. It is designed to be housed in the optical system of.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 shows a display optical system according to a first embodiment of the present invention. This display optical system includes an image display element (LC
D etc.) in order, a first optical system 30 having a positive optical power (1 / focal length) as a whole and a second optical system 20 having a positive optical power as a whole are provided. Is configured.

In the present embodiment, both the first optical system 30 and the second optical system 20 have a transparent body (hereinafter referred to as an optical element) 31, the inside of which is filled with an optical medium such as glass or plastic. An optical surface is formed on 21.

The light modulated and emitted by the image display element 10 is incident on the second optical element 21 from the surface 21a, and the surface 2a.
The second optical element 21 is reflected by 1b and transmitted through the surface 21c.
Inject. The light emitted from the second optical element 21 from the emission surface 21c passes through the surface 31a (third surface) and enters the first optical element 31.

Light incident on the first optical element 31 from the incident surface 31a is reflected by the surface 31b (first surface), and the surface 31c
The light is reflected back in the substantially opposite direction on the (second surface), and the surface 31b
At the hit point, the surface is re-reflected on the side opposite to the previous side with respect to the normal of the surface, reflected on the surface 31a,
The first optical element 31 passes through the
Be led to. The surface 31a is provided with a half mirror coating.

In this figure, as an example of the luminous flux emitted from the image display element 10, the exit pupil of the display optical system is emitted by exiting the center of the display surface of the image display element 10 (corresponding to the position of the observer's eye E).
The central ray of the central angle of view reaching the center of is indicated by a solid line.

By constructing the first optical element 31 and the second optical element 21 to have a positive optical power, the observer visually recognizes an enlarged image of the image displayed on the image display element 10. It becomes possible.

As shown in FIG. 1, by arranging the reflecting surface on the first optical element 31 so as to be decentered with respect to the central angle-of-view chief ray, the optical path is obliquely folded and the first optical element 31 is arranged. It has been made thinner.

At this time, at least one of the optical surfaces on the first optical element 31 is corrected in order to correct the decentering aberration caused by the decentered arrangement of the surface having optical power.
It is preferable that the two surfaces are rotationally asymmetrical surfaces (so-called free-form surfaces) having different optical powers depending on the azimuth angle.

In particular, a concave surface facing the eye E of the observer (that is, a convex surface facing the second optical system 20) which takes charge of the main power of the positive optical power as a whole of the first optical element 31. It is preferable from the viewpoint of aberration correction that the surface 31a having the shape is formed by a free-form surface.

More preferably, by forming all the optical surfaces on the first optical element 31 with free-form surfaces, better optical performance can be obtained. At this time, if each rotationally asymmetric surface has a plane-symmetrical shape in the direction perpendicular to the paper surface with the cross-section of the paper being the only plane of symmetry, processing and manufacturing can be facilitated as compared to the case where there is no symmetry. ,
preferable.

In the first optical element 31, the light is the surface 31
a → face 31b → face 31c → face 31b → face 31a (→ face 3
1b) in order, and the optical path up to that point is traced in reverse, with the reflection at the surface 31c as the boundary. Surface 31a → surface 31b → surface 31
The optical path to c is the forward path, and the surface 31c → the surface 31b → the surface 31a
Is called a return path, and a reciprocating optical path is formed by these outward and return paths. The surface 31c is referred to as a folded reflection surface.

In this way, by forming the reciprocating optical path in the first optical system 30 by using the surface 31c as a reflection reflecting surface,
The first optical element 31 is folded so as to overlap the optical path, and the space in the first optical element 31 is effectively used.
The first optical system 30 can be miniaturized with respect to the optical path length. Thereby, the entire display optical system including the second optical system 20 can be downsized.

By forming the reciprocating optical path, the first optical system 30 can be miniaturized, but since the optical surfaces are used redundantly, the degree of freedom in design is lowered, and the optical performance is lowered and the manufacturing is reduced. There is concern that the tolerance will decrease.

However, in this embodiment, the entrance surface 31a of the first optical element 31 and the exit surface 21 of the second optical element 21 are used.
By disposing c and c so as to face each other with an air layer (air gap) interposed therebetween, and by using separate surfaces instead of the bonding surface, the optically effective surface in the optical path can be determined without affecting the size of the optical system. We have increased the degree of freedom in design and improved optical performance.

Further, since the difference in the refractive index of the medium before and after the incidence on the surfaces 31a and 21c can be set to be large, the concave shape toward the eye E of the observer (the convex shape toward the second optical system 20). ) Has a surface 31a and the first optical system 3
Since the convex lens action upon incidence on the surface 21c having a convex shape toward 0 can be obtained with a small curvature while having the same optical power, the occurrence of aberration can be suppressed.

Further, if the reflection on the surface 31b is the total reflection, the light quantity loss is reduced, which is preferable. Further, if the reflected light flux is totally reflected at least in the area where the reflected light flux and the outgoing light flux are shared on the surface 31b, the degree of freedom in design can be increased as compared with the case where the entire reflected light flux is totally reflected. it can.

As described above, the reflection on the optical surface having both the transmitting function and the reflecting function is the total reflection, so that the light can be efficiently used.

Further, as shown by the dotted line in FIG. 1, the rays of light which are emitted from the center of the image display surface of the image display element 10 and reach both ends of the exit pupil of the display optical system are also surface 31a → surface 31b → surface 31c. → The surface 31b → the surface 31a (→ the surface 31b) and the same route as the central angle of view chief ray are traced. At this time, light rays from both ends intersect in the optical path of the first optical system 30, and an intermediate image of the image displayed on the image display element 10 is formed.

As a result, the degree of freedom in setting the display angle of view with respect to the display size of the image display element 10 is improved, and a wide angle of view (high-magnification display) is made possible. Further, in order to facilitate the so-called aberration correction of the so-called eyepiece optical system portion that guides the intermediate image to the observer's eye E as substantially parallel light, the intermediate image forming surface has a field curvature, astigmatism, and astigmatism in the eyepiece optical system portion. It may be formed so as to be appropriately curved, have an astigmatic difference, or be distorted in accordance with the situation in which distortion occurs.

Further, by forming the first optical element 31 and the second optical element 21 with materials having the same refractive index, the manufacture of these optical elements 31 and 21 becomes easy.

By configuring the display optical system as described above, it is possible to provide an image display device which displays an image displayed on the image display element 10 as a magnified image with good optical performance.

Further, by forming an image once in the display optical system, the degree of freedom in setting the display angle of view with respect to the display size of the image display element 10 is improved and a wide angle of view (high magnification display) is made possible. At the same time, the optical path length is increased accordingly. By forming a reciprocal optical path in the first optical element 31, the optical paths are overlapped and the total length of the display optical system is suppressed to be short, thereby forming a very compact display optical system. it can.

It should be noted that in the present embodiment, the reflected reflection on the surface 31c of the central ray at the central angle of view is drawn to be substantially vertical reflection, but the display optical system of the present invention is not limited to this configuration. .

(Second Embodiment) FIGS. 2 and 3 show a display optical system according to a second embodiment of the present invention. A first optical system 30 ', which constitutes the display optical system of the present embodiment,
30 "and the second optical system 20 ', 20" are different from those of the first embodiment.

In the display optical system shown in FIG. 2, the light emitted from the image display element 10 is transmitted from the surface 22a to the second optical system 2.
It is incident on the optical element (second optical element) 22 that constitutes 0 ′, is reflected by the surface 22b, is totally reflected by the surface 22a, and is surface 22c.
The second optical element 22 is emitted from. The light emitted from the second optical system 20 'from the emission surface 22c is first emitted from the surface 31a.
Transparent body (first optical element) 3 constituting the optical system 30 'of
Incident on 1.

The light incident on the first optical element 31 from the incident surface 31a is reflected by the surface 31b, reflected back by the surface 31c, re-reflected by the surface 31b, and reflected by the surface 31a.
The first optical element 31 is emitted from b and guided to the eye E of the observer.

In the display optical system shown in FIG. 3, the light emitted from the image display element 10 is refracted by the lenses 23, 24 and 25 of the second optical system 20 ″ and emitted from the emission surface 25a. The light enters the transparent body (first optical element) 31 of the first optical system 30 ″. The light incident on the first optical element 31 from the incident surface 31a is reflected by the surface 31b, reflected back by the surface 31c, re-reflected by the surface 31b, reflected by the surface 31a, and reflected by the surface 31b from the first optical element. 31 is emitted and guided to the observer's eye E.

In the display optical system shown in FIGS. 2 and 3,
In both of the first optical systems 30 'and 30 ", the surface 31a
→ surface 31b → surface 31c → surface 31b → surface 31a → surface 31b
The point that a round-trip optical path is formed is the same as in the first embodiment.

However, in FIG. 2, the central angle-of-view chief ray reflected by the surface 31b is reflected back at an angle θ with respect to the incident ray on the surface 31c, and is lower than the first reflection point of the surface 31b. It is different from the first embodiment in that it is re-reflected at a position.

Further, in FIG. 3, the central angle-of-view chief ray reflected by the surface 31b is reflected back at the surface 31c at an angle θ with respect to the incident ray, and is reflected more than at the first reflection point of the surface 31b. It is different from the first embodiment in that it is re-reflected at a high position.

As described above, the light rays may be incident and reflected at a predetermined angle θ before and after the folding reflection surface 31c. However, it is preferable that the angle θ satisfies | θ | <30 °. If this condition is not satisfied, the prism member 31 becomes large and it becomes difficult to reduce the size of the entire optical system.
Not preferable.

Further, the second optical system 20 'can be made smaller by folding the optical path by using the reflecting surface as shown in FIG. At this time, in order to correct the eccentric aberration generated by arranging the surfaces having optical power eccentrically, at least one of the optical surfaces constituting the second optical system 20 ′, 20 ″ is decentered. It is preferably composed of a rotationally asymmetric surface.

In order to increase the number of optical surfaces that contribute to aberration correction, the second optical system may be constructed by using two or more optical members including a reflecting surface.

Further, as shown in FIG. 3, the second optical system 20 ″ may be composed of only a refracting surface, and particularly the concave lens 2
By using No. 4, it becomes easy to correct chromatic aberration, and further improvement in imaging performance can be expected.

Further, by constructing the refracting surface with a free-form surface or a decentered rotationally symmetric aspherical surface, it becomes easy to correct decentering aberrations, and further improvement in imaging performance can be expected.

(Third Embodiment) FIG. 4 shows a third embodiment of the present invention.
1 illustrates a display optical system that is an embodiment. To facilitate understanding, the first optical system is shown in a simplified manner. The display optical system may be configured by combining each with the second optical system 20 shown in FIGS. 1 to 3.

The display optical system according to the present embodiment has the eye E of the observer.
From the side toward the image display element (LCD or the like) 10,
The first optical system 130 has a positive optical power (1 / focal length) as a whole, and the second optical system 120 has a positive optical power as a whole.

In this embodiment, the first optical system 130 is
An optical surface is formed on a transparent body (first optical element) 32 whose inside is filled with an optical medium such as glass or plastic.

The light modulated and emitted by the image display element 10 enters the second optical system 120 through the incident surface 20a,
The second optical system 20 is emitted from the emission surface 20b, and the surface 32a
Is incident on the first optical element 32.

The light incident on the first optical element 32 from the incident surface 32a (third surface) is reflected by the surface 32b (first surface) and reflected by the surface 32c (second surface). The light is reflected back at the upper part of 32b, re-reflected at the surface 32c, re-reflected at the surface 32b on the opposite side to the normal of the surface on the hit point, reflected at the surface 32a, and reflected at the surface 32b. The light passes through the transparent body 32 and is guided to the observer's eye E. A half mirror coating is applied to the surface 32a.

First optical system 130 and second optical system 1
By configuring 20 to have a positive optical power, the observer can visually recognize an enlarged image of the image displayed on the image display element 10.

In the first optical element 32, the light is the surface 32
a → plane 32b → plane 32c → plane 32b → plane 32c → plane 32
b → face 32a (→ face 32b) in order, and face 32
Following the reflection at b, the optical path up to that point is followed in reverse.

In this way, by forming the reciprocating optical path in the first optical system 130 by using the surface 32b as a reflection reflecting surface, the first optical system 130 with respect to the optical path length as in the first embodiment. Is downsized. Thereby, the entire display optical system including the second optical system 120 can be downsized.

The optical surface on the first optical element 32 is a rotationally asymmetric surface, and the exit surface 20 of the second optical system 120 is formed.
By providing an air layer (air gap) between b and the incident surface 32a of the first optical system 130, the optical performance is improved as described in the first embodiment.

(Fourth Embodiment) FIG. 5 shows a fourth embodiment of the present invention.
1 illustrates a display optical system that is an embodiment. To facilitate understanding, the first optical system is shown in a simplified manner. The display optical system may be configured by combining each with the second optical system 20 shown in FIGS. 1 to 3.

The display optical system according to the present embodiment has the eye E of the observer.
From the side toward the image display element (LCD or the like) 10,
The first optical system 230 has a positive optical power (1 / focal length) as a whole, and the second optical system 120 has a positive optical power as a whole.

In this embodiment, the first optical system 230 is
It is composed of a transparent body (optical element) 33 whose inside is filled with an optical medium such as glass or plastic, and a reflection mirror member 34.

The light modulated and emitted by the image display element 10 enters the second optical system 120 through the incident surface 20a,
The second optical system 120 is emitted from the emission surface 20b, and the surface 33
It is incident on the optical element 33 of the first optical system 230 from a.

From the entrance surface 33a (third surface) to the optical element 3
The light incident on the light source 3 (first optical system 230) is reflected by the surface 33b.
The light is reflected by the (first surface), the optical element 33 is emitted from the surface 33c, and the reflection surface 34a (second surface) of the reflection mirror member 34 is formed.
The light is reflected and reflected again at the surface 33c, enters the optical element 33 from the surface 33c again, and is reflected again on the surface 33b on the opposite side to the normal line of the surface on the hit point of the surface 33b. Is emitted through the optical element 33 and is guided to the eye E of the observer. A half mirror coating is applied to the surface 33a.

The second optical system 120 is constructed so as to have a positive optical power, and at least one of the optical surfaces constituting the first optical system 230 is made a curved surface to the first optical system 230. With the optical power of 1, the observer can visually recognize a magnified image of the image displayed on the image display element 10.

In the first optical system 230, the light is reflected on the surface 33.
a → plane 33b → plane 33c → plane 34a → plane 33c → plane 33
b → face 33a (→ face 33b) in order, and face 34
The optical path up to that point is traced in reverse, with the reflection at a as the boundary.

As described above, by forming the reciprocating optical path in the first optical system 230 by using the surface 34a as a reflection reflecting surface, the first optical system 230 can be moved with respect to the optical path length as in the first embodiment. It is becoming smaller. Thereby, the entire display optical system including the second optical system 120 can be downsized.

Further, the exit surface 20b of the second optical system 120
By providing an air layer (air gap) between the light incident surface 33a and the entrance surface 33a of the first optical system 230, the optical performance is improved as described in the first embodiment.

Further, in this embodiment, the first optical system 2
In 30, the reflection mirror member 34 including the folded reflection surface 34 a is formed as a member different from the transparent body 33,
The number of optical surfaces in the optical path is increased without affecting the size of the optical system, the degree of freedom in design is increased, and the optical performance is improved.

(Fifth Embodiment) FIG. 6 shows a fifth embodiment of the present invention.
1 illustrates a display optical system that is an embodiment. To facilitate understanding, the first optical system is shown in a simplified manner. The display optical system may be configured by combining each with the second optical system 20 shown in FIGS. 1 to 3.

The display optical system according to the present embodiment has the eye E of the observer.
From the side toward the image display element (LCD or the like) 10,
The first optical system 330 has a positive optical power (1 / focal length) as a whole, and the second optical system 120 has a positive optical power as a whole.

In this embodiment, the first optical system 330 is
It is composed of a transparent body (optical element) 35 whose inside is filled with an optical medium such as glass or plastic, and a reflection mirror member 36.

The light modulated and emitted by the image display element 10 enters the second optical system 120 through the incident surface 20a,
The second optical system 120 is emitted from the emission surface 20b, and the surface 35
It is incident on the optical element 35 of the first optical system 330 from a.

From the incident surface 35a (third surface) to the optical element 35
The light flux incident on the (first optical system 330) is reflected by the surface 35b, reflected by the surface 35c (first surface), emitted from the surface 35b to the optical element 35, and reflected by the reflecting surface 3 of the reflecting mirror member 36.
The light is reflected back at 6a (the second surface). And face 35
It is incident on the optical element 35 again from b, re-reflected on the surface 35c, re-reflected on the surface 35b on the opposite side to the normal of the surface on the hit point, and further reflected on the surface 35a, The light passes through the surface 35b, emerges from the optical element 35, and is guided to the eye E of the observer. A half mirror coating is applied to the surface 35a.

The second optical system 120 is constructed to have a positive optical power, and at least one of the optical surfaces constituting the first optical system 330 is used as a curved surface in the first optical system 330. By giving the positive optical power, the observer can visually recognize an enlarged image of the image displayed on the image display element 10.

In the first optical system 330, the light is on the surface 35.
a → face 35b → face 35c → face 35b → face 36a → face 35
The path b is passed through in the order of b → surface 35c → surface 35b → surface 35a (→ surface 35b), and the optical path up to that point is traced in reverse with the return reflection at the surface 36a.

As described above, by forming the reciprocating optical path in the first optical system 330 by using the surface 36a as a reflection reflecting surface, the first optical system 330 with respect to the optical path length as in the first embodiment. Is downsized. Thereby, the entire display optical system including the second optical system 120 can be downsized.

Further, the exit surface 20b of the second optical system 120
By providing an air layer (air gap) between the light incident surface 35a of the first optical system 330 and the first optical system 330, the optical performance is improved for the same reason as described in the first embodiment.

Further, in this embodiment, the first optical system 3
In 30, the reflection mirror member 36 including the folded reflection surface 36a is formed separately from the optical element 35, so that the number of optical surfaces in the optical path can be increased without affecting the size of the optical system, and the design can be freely performed. The optical performance is improved by increasing the degree.

In the fourth embodiment (FIG. 5) and the fifth embodiment (FIG. 6), the reflecting mirror members 34 and 3 are provided.
It is preferable that the reflecting surfaces 34a and 36a of No. 6 are curved surfaces from the viewpoint of increasing the number of image forming surfaces. further,
By making these reflecting surfaces 34a, 36a eccentric and rotationally asymmetric, it is possible to contribute to the correction of decentration aberrations generated in the optical elements 33, 35 and improve the optical performance.

Further, in the fourth embodiment, the reflecting mirror member 34 is a rear surface mirror as in the modification shown in FIG. 7, so that not only the reflecting surface 34a but also the transmitting surface 34b can be used as an optical surface. Therefore, the imaging performance can be further improved without affecting the size of the optical system.

Further, as in the modified example shown in FIG. 8, by configuring the reflection mirror member 34 with two or more optical elements, it becomes easy to correct chromatic aberration and further improve the imaging performance. .

The reflection mirror member 3 shown in FIGS.
The configuration of 4 ', 34 "can be applied to the reflection mirror member 36 used in the fifth embodiment.

Further, in the fourth and fifth embodiments, similarly to the first embodiment, the first embodiment is used in order to correct the eccentric aberration caused by arranging the surface having optical power in a decentered manner. It is preferable that at least one of the surfaces forming the optical systems 230 and 330 (optical elements 33 and 35) is a rotationally asymmetric surface.

Also in the third to fifth embodiments described above, as in the first embodiment, in the optical path of the first optical system,
By forming the intermediate image formation surface of the display surface of the image display element 10, a wide angle of view (high-magnification display) becomes possible.

In the optical element of the first optical system,
By making the reflection on the surface having both the transmissive action and the reflective action the total reflection, the light can be efficiently used.

Furthermore, also in the third to fifth embodiments, the return reflection of the central angle-of-view principal ray on the return reflection surface is not limited to the vertical reflection, and as shown in the second embodiment, the return reflection surface of the return reflection surface is not limited to the vertical reflection. The ray is at a certain angle θ before and after
May be incident and reflected.

By constructing the display optical system as in the above third to fifth embodiments, an image display device for displaying an image displayed on the image display element 10 as a magnified image with good optical performance is provided. can do.

Further, by forming an image once in the display optical system, the degree of freedom in setting the display angle of view with respect to the display size of the image display element 10 is improved and a wide angle of view (high magnification display) is possible. The first is that the optical path length increases with this.
By forming a reciprocating optical path in the optical system, the optical paths are overlapped, the overall length of the display optical system is suppressed to be short, and a very compact display optical system can be configured.

(Sixth Embodiment) FIG. 9 shows a sixth embodiment of the present invention.
1 illustrates a display optical system that is an embodiment. The display optical system of the present embodiment includes an image display element (LC
(D etc.) 10 in order, the first optical system 430 having a positive optical power (1 / focal length) as a whole and the second optical system 220 having a positive optical power as a whole.
And is configured.

In this embodiment, the first optical system 430 is
A transparent body (first optical element) 37 whose inside is filled with an optical medium such as glass or plastic;
The optical system 220 is also composed of a transparent body (second optical element) 26 filled with the same optical medium. The traveling paths of light in the first and second optical systems are the same as those shown in FIG.

In this embodiment, an air layer (air gap) is provided between the entrance surface (third surface) 37a of the first optical element 37 and the exit surface 26 of the second optical element 26. , First
The optical element 37 and the second optical element 26 are configured to be in contact with each other at a portion other than the entrance surface 37a of the first optical element 37 and the exit surface 26 of the second optical element 26 (outside the light ray effective range). is doing.

As a result, the dimensional error (manufacturing error) of the air layer can be suppressed to be small, and the deterioration of the optical performance due to the manufacturing error can be prevented.

An optical system similar to the display optical system of each of the embodiments described above can also be used as an image pickup optical system that guides light from a subject to the image pickup surface of an image pickup device such as a CCD.

For example, taking the optical system shown in the first embodiment as an example, the light passes through the first surface (31b) from the subject and enters the first optical system 30 (first optical element 31). The light is reflected by the third surface (31a) and is reflected by the first surface (31b).
Reflected on the second surface (the surface 31c) and then on the first surface (31b), it is re-reflected to the opposite side to the normal of the surface on the hit point, and the third surface Surface (31
The light a) is transmitted and guided to the second optical system 20. Then, the light incident on the second optical system 20 from the surface 21c is transferred to the surface 21b.
The light is reflected by, and is transmitted through the surface 21a to reach the image pickup element arranged in place of the image display element 10.

Also in this case, similarly to the display optical system, in the first optical system 30, the light path can be folded back and forth between the first, second and third surfaces, so that the optical path can be folded down. Even though it is an optical system, it can secure a long optical path length. For this reason, it is possible to achieve a wide shooting angle of view while being compact.

Further, an intermediate image formation type in which light is formed into an intermediate image in the image pickup optical system (for example, the first optical element 31), that is, the intermediate image formation surface of the object is reduced and guided to the image pickup surface. By doing so, the degree of freedom of layout increases,
It is possible to sufficiently reduce an object image having a wide angle of view and guide it to the imaging surface, and it is possible to configure the imaging optical system in a small size even if the optical path length is considerably long.

The merits of decentering the optical surface constituting the image pickup optical system with respect to light, giving the optical surface a curvature, and making the optical surface a rotationally asymmetric surface (free curved surface) are It is similar to the system.

Numerical examples of the above embodiments will be described below.

[Numerical Example 1] FIG. 10 shows an optical path sectional view of a numerical example of the first embodiment shown in FIG. In the figure, reference numeral 30 denotes a first optical system, which is composed of a prism-shaped transparent body (first optical element) 31 having three optical surfaces. S2, S4, S6 are the same surface, S
3, S7 are the same surface, and these two surfaces and S5 are the surfaces 31b, 31a, 31 described in the first embodiment, respectively.
Corresponds to c.

Reference numeral 20 is a second optical system, and here, S
The transparent body (second optical element) 21 is composed of the same medium and has three surfaces of 8, S9, and S10. These three surfaces are the surfaces 21 described in the first embodiment.
c, 21b, 21a. SI is the image display surface, S
Reference numeral 1 is an exit pupil S of the display optical system.

In this numerical example, the optical surfaces from S1 to S10 are rotationally asymmetrical surfaces and have a plane symmetric shape having the paper surface (yz section) as the only symmetric surface.

Note that x, y, and z in the figure are coordinate system definitions with the observer's visual axis direction as the z-axis, the direction perpendicular to the z-axis in the paper plane as the y-axis, and the direction perpendicular to the paper plane as the x-axis. Is.

Table 1 shows the optical data of Numerical Data Example 1. The leftmost item SURF in the optical data in Table 1 indicates the surface number. Also, X, Y, Z and A are the first
The center of the surface S1 is the origin (0, 0, 0), and the position of the surface apex of each surface (x, y, in the coordinate system in which the y-axis and the z-axis shown in the figure and the x-axis in the depth direction of the paper are taken). z) and the rotation angle a (unit: degree) about the x-axis with the counterclockwise direction as the positive direction on the drawing.

R is the radius of curvature. The term TYP represents the type of surface shape, SPH is a spherical surface, and FFS is a rotationally asymmetric surface according to the following equation.

[0122]

[Equation 1]

The numerical values next to FFS in the TYP column correspond to the aspherical surface coefficients k and ci (i = 1, 2, 3 ...) Described at the bottom of the table for the shape of the surface. It shows that the shape is rotationally asymmetric.

Nd and νd (however, indicated as vd in the table) respectively indicate the refractive index and the Abbe number at the d-line wavelength of the medium after that surface, and the change in the sign of the refractive index N at that surface. It shows that the light is reflected. When the medium is an air layer, only the refractive index Nd is displayed as 1.000,
Abbe number νd is omitted.

The items in the above table are the same in the following numerical examples.

[0126]

[Table 1]

As can be seen from Table 1, the light from the image display surface SI enters the second optical element 21 from S10 (surface 21a), is reflected by S9 (surface 21b), and is reflected by S8 (surface 21c).
And then the second optical element 21 is emitted. The light emitted from the exit surface (S8) of the second optical element 21 passes through S7 (surface 31a) and enters the first optical element 31 (first optical system 30), and S6 (surface 31b). Reflected by, reflected back by S5 (surface 31c), re-reflected by S4 (surface 31b), reflected by S3 (surface 31a), transmitted through S2 (surface 31b), and emitted from the first optical element 31. Then, it is guided to the exit pupil S1. The observer can observe the magnified image on the image display surface by placing his eyes at the exit pupil position.

Considering the numerical value having the dimension of length in the present numerical value example 1 as mm, the exit pupil diameter is φ6 mm,
Image display size 10mm x 7.5mm, horizontal approximately 5
It is a display optical system that displays an image in the positive infinity direction of the z axis at an angle of view of 0 ° and a vertical angle of about 39 °.

The optical system of this numerical example may be used as an image pickup optical system. In this case, the light from the subject at infinity in the negative direction of the z-axis passes through the diaphragm S1, enters the first optical element 31 from S2, is reflected by S3, S4, S5, and S6, and is reflected by S7 from the first. The optical element 31 is emitted. The light emitted from the first optical element 31 is guided to the second optical element 21, and forms an external (subject) image on the imaging surface SI via S8, S9, and S10.

[Numerical Example 2] FIG. 11 is an optical sectional view showing a numerical example of the second embodiment shown in FIG. 2. Optical data are shown in Table 2.

In the figure, reference numeral 30 'denotes a first optical system, which is composed of a prism-shaped transparent body (first optical element) 31 having three optical surfaces. S2, S4 and S6 are the same surface, S3 and S7 are the same surface, and these two surfaces and S5 are the surfaces 31b and 31 described in the second embodiment, respectively.
a, 31c.

Reference numeral 20 'denotes a second optical system, here S
It is composed of a transparent body (second optical element) 22 made of the same medium and having three surfaces of 8, S9 (same surface as S11) and S10. These three surfaces correspond to the surfaces 22c, 22a, 22b described in the first embodiment, respectively. S
I is the image display surface, and S1 is the exit pupil S of the display optical system.

In this numerical example, the optical surfaces from S1 to S11 are rotationally asymmetrical surfaces and have a plane symmetric shape having the paper surface (yz section) as the only symmetric surface.

Note that x, y, and z in the drawing are coordinate system definitions with the visual axis direction of the observer as the z axis, the direction perpendicular to the z axis in the paper surface as the y axis, and the direction perpendicular to the paper surface as the x axis. Is.

The light from the image display surface SI is S11 (surface 2
2a) to enter the second optical element 22, and S10 (Surface 2)
It is reflected by 2b), reflected by S9 (surface 22a), transmitted through S8 (surface 22c), and emitted from the second optical element 22.
The light emitted from the exit surface (S8) of the second optical system 20 ′ passes through S7 (the surface 31a) and then passes through the first optical element 31.
It is incident on the (first optical system 30 ′), reflected by S6 (surface 31b), reflected back by S5 (surface 31c), re-reflected by S4 (surface 31b), reflected by S3 (surface 31a). , S2
The first optical element 31 is emitted through the (surface 31b),
It is guided to the exit pupil S1.

The observer can observe the magnified image on the image display surface by placing his eyes at the exit pupil position.

[0137]

[Table 2]

Numerical Example 2 is a display optical system having substantially the same specifications as Numerical Example 1 when a numerical value having a dimension of length is considered as mm.

The optical system of this numerical example may be used as an image pickup optical system. In this case, the light from the subject at infinity in the negative direction of the z-axis passes through the diaphragm S1, enters the first optical element 31 from S2, is reflected by S3, S4, S5, and S6, and is reflected by S7 from the first. The optical element 31 is emitted. The light emitted from the first optical element 31 is guided to the second optical element 22 and forms an external (subject) image on the imaging surface SI via S8, S9, S10, and S11.

[Numerical Example 3] FIG. 12 is an optical sectional view showing a numerical example of the third embodiment shown in FIG. 4, and Table 3 shows optical data.

In the figure, reference numeral 130 denotes a first optical system, which is composed of a prism-shaped transparent body (first optical element) 32 having three optical surfaces. S2, S4, S6, S
8 is the same surface, S3, S9 are the same surface, S5, S7 are the same surface, and these three surfaces correspond to the surfaces 32b, 32a, 32c described in the third embodiment, respectively.

Reference numeral 120 denotes a second optical system, and here, S
It is composed of a transparent body (second optical element) 21 having the three surfaces 10, S11 and S12 and made of the same medium.
These three surfaces are the surfaces 2 described in the first embodiment of FIG.
1c, 21b, 21a. SI is the image display surface,
S1 is an exit pupil S of the display optical system.

In this numerical example, the optical surfaces from S1 to S12 are rotationally asymmetrical surfaces and have a plane symmetric shape having the paper surface (yz section) as the only symmetric surface.

Note that x, y, and z in the figure are coordinate system definitions with the visual axis direction of the observer as the z axis, the direction perpendicular to the z axis in the paper plane as the y axis, and the direction perpendicular to the paper plane as the x axis. Is.

The light from the image display surface SI is S12 (surface 2
1a) is incident on the second optical element 21 and S11 (Surface 2)
It is reflected by 1b), passes through S10 (surface 21c), and is emitted from the second optical element 21.

The light emitted from the exit surface (S10) of the second optical element 21 passes through S9 (the surface 32a) and enters the first optical element 32 (the first optical system 130), and S8 ( S6 (face 32b), S7 (face 32c), S6
The light is reflected back at (face 32b), re-reflected at S5 (face 32c), reflected at S4 (face 32b), and S3 (face 32a).
Is reflected by the first optical element 32, is transmitted through S2 (surface 32b), and is guided to the exit pupil S1.

The observer can observe the magnified image on the image display surface by placing his eyes at the exit pupil position.

[0148]

[Table 3]

Numerical Example 3 is a display optical system having substantially the same specifications as Numerical Example 1 when a numerical value having a dimension of length is considered as mm.

The optical system of this numerical example may be used as an image pickup optical system. In this case, the light from the object point at the infinity in the negative direction of the z-axis passes through the stop S1 and the first optical element 32.
Be led to. Then, the light enters the first optical element 32 from S2, is reflected at S3, is reflected at S4, is reflected at S5, and is reflected at S5.
After being reflected back at 6, the light is reflected at S7, reflected at S8, emitted from the first optical element 32 at S9, and guided to the second optical element 22. The light guided to the second optical element 22 forms an image on the imaging surface SI via S10, S11, and S12.

[Numerical Example 4] FIG. 13 is an optical sectional view showing another numerical example of the third embodiment shown in FIG.
The optical data are shown in Table 4.

In the figure, reference numeral 130 denotes a first optical system, which is composed of a prism-shaped transparent body (first optical element) 32 having three optical surfaces. S2, S4, S6, S
8 is the same surface, S3, S9 are the same surface, S5, S7 are the same surface, and these three surfaces correspond to the surfaces 32b, 32a, 32c described in the third embodiment, respectively.

Reference numeral 20 'denotes a second optical system, here S
The transparent body (second optical element) 22 is made of the same medium and has three surfaces 10, S11 (same surface as S13) and S12. These three surfaces correspond to the surfaces 22c, 22a, 22b described in the second embodiment of FIG.
SI is an image display surface, and S1 is an exit pupil S of the display optical system.

In this numerical example, the optical surfaces from S1 to S13 are rotationally asymmetrical surfaces and have a plane symmetric shape having the paper surface (yz section) as the only symmetric surface.

Note that x, y, and z in the figure are coordinate system definitions with the observer's visual axis direction as the z axis, the direction perpendicular to the z axis in the paper plane as the y axis, and the direction perpendicular to the paper plane as the x axis. Is.

The light from the image display surface SI is S13 (surface 2
2a) to enter the second optical element 22, and S12 (Surface 2)
2b), S11 (surface 22a), S10
The light passes through the (face 22c) and is emitted from the second optical element 22.

The light emitted from the exit surface (S10) of the second optical element 22 passes through S9 (surface 32a) and enters the first optical element 32 (first optical system 130), and S8 ( S6 (face 32b), S7 (face 32c), S6
The light is reflected back at (face 32b), re-reflected at S5 (face 32c), reflected at S4 (face 32b), and S3 (face 32a).
Is reflected by the first optical element 32, is transmitted through S2 (surface 32b), and is guided to the exit pupil S1.

The observer can observe the magnified image on the image display surface by placing his eyes at the exit pupil position.

[0159]

[Table 4]

Numerical Example 4 is a display optical system having substantially the same specifications as Numerical Example 1 when the numerical value having the dimension of length is considered as mm.

The optical system of this numerical example may be used as an image pickup optical system. In this case, the light from the object point at the infinite distance in the negative direction of the z-axis passes through the stop S1 and then the first optical system 130.
Be led to. Then, the light enters the first optical element 32 from S2, is reflected at S3, is reflected at S4, is reflected at S5, and is reflected at S5.
After being reflected back at 6, the light is reflected at S7, reflected at S8, emitted from the first optical element 32 at S9, and guided to the second optical element 22. The light guided to the second optical element 22 passes through S10, S11, S12, and S13, and the imaging surface S
Form an image on I.

[Numerical Example 5] FIG. 14 is an optical sectional view showing a numerical example of the fifth embodiment shown in FIG. 6, and optical data are shown in Table 5.

In the figure, reference numeral 330 denotes a first optical system, which is a prism-shaped transparent body (optical element) 3 having three optical surfaces.
5 and the reflection mirror member 36. S
2, S4, S6, S8 and S10 are on the same plane, S3 and S11
Is the same surface, S5 and S9 are the same surface, and these three surfaces are the surfaces 35b and 35 described in the fifth embodiment, respectively.
a, corresponding to 35c. Further, S7 corresponds to the surface 36a described in the fifth embodiment.

Reference numeral 120 denotes a second optical system, and here, S
The transparent body (second optical element) 22 is made of the same medium and has two surfaces S12 and S13. SI is an image display surface, and S1 is an exit pupil S of the display optical system.

In this numerical example, the optical surfaces from S1 to S13 are rotationally asymmetrical surfaces and have a plane symmetric shape having the paper surface (yz section) as the only symmetric surface.

Note that x, y, and z in the figure are coordinate system definitions in which the observer's visual axis direction is the z axis, the direction perpendicular to the z axis in the paper is the y axis, and the direction perpendicular to the paper is the x axis. Is.

The light from the image display surface SI passes through S13 of the second optical system 120, exits S12, passes through S11 (surface 35a), and passes through the optical element 35 of the first optical system 130.
Incident on. Then, the light is reflected by S10 (surface 35b), and S
The light is emitted from the optical element 35 while being reflected by 9 (surface 35c) and refracted by S8 (surface 35b).

The emitted light is reflected back at S7 (surface 36a), passes through S6 (surface 35b), and is again reflected by the optical element 35.
Incident on S5 (surface 35c) and reflected on S4 (surface 35c).
b), S3 (Surface 35a), S2 (Surface 3)
5b) and then exits the optical element 35 and is guided to the exit pupil S1.

The observer can observe the magnified image on the image display surface by placing his eyes at the exit pupil position.

[0170]

[Table 5]

Numerical Example 5 is a display optical system having substantially the same specifications as Numerical Example 1 when a numerical value having a dimension of length is considered as mm.

The optical system of this numerical example may be used as an image pickup optical system. In this case, the light from the object point at the infinity in the negative direction of the z-axis passes through the stop S1 and the first optical system 330.
Be led to. Then, the light enters the optical element 35 of the first optical system 330 from S2, is reflected at S3, is reflected at S4, and is reflected at S4.
The light is reflected at 5, passes through S6, and is emitted from the optical element 35. After that, the light is reflected back at S7 (reflection mirror member 36), passes through S8, enters the optical element 35 again, is reflected at S9, is reflected at S10, passes through S11, and exits the optical element 35. Then, it is guided to the second optical system 120. The light guided to the optical element 22 of the second optical system 120 forms an image on the image pickup surface SI of the image pickup element such as a CCD via S12 and S13.

In all the embodiments described above, when an arbitrary ray of the light flux passing through the first optical system is traced, the ray is first (1) on the first surface.
An optical path is set for the second reflection and the second reflection with one reflection angle as a reference and the other reflection angle with the opposite sign.

Specifically, for example, in the paper surface of FIG. 1, when the reflection angle in the first reflection (reflection on the surface 31b) is a positive sign (the reflected light exists in the counterclockwise direction in the paper surface of the normal line). ), The optical path is such that the reflection angle in the second reflection (re-reflection on the surface 31b) has a negative sign (when the reflected light exists in the clockwise direction on the paper surface of the normal line).

By taking such an optical path, the first
Since the light flux substantially reciprocates between the first surface and the second surface, it is possible to effectively utilize the space in the first optical system to earn an optical path length. Moreover, a small optical system can be realized even if the optical path length is long.

[0176]

As described above, according to the first invention of the present application, in the first optical system, the first, second and third optical systems are provided.
Since the light is substantially reciprocated between the surfaces of and the optical path is folded back, a long optical path can be ensured even though the optical system is small. For this reason, it is possible to achieve a wide display angle of view while using a small original image, and it is possible to reduce the size of the entire display optical system including the second optical system.

By providing an air gap between the third surface of the first optical system and the exit surface of the second optical system,
Since a large number of optical surfaces can be secured and the degree of freedom in optical design can be increased, it is possible to improve the optical performance of the display optical system and further downsize it.

If the light is formed into an intermediate image in the display optical system (for example, a transparent body), the degree of freedom in layout is increased, the original image can be displayed on a large screen, and the optical path length is considerably long. However, the display optical system can be made compact.

Further, according to the second invention of the present application, in the first optical system, since the light is substantially reciprocated between the first, second and third surfaces to return the optical path, the optical system is compact. Even though it is an optical system, it can secure a long optical path length. For this reason, it is possible to achieve a wide shooting angle of view while the size of the entire imaging optical system including the second optical system is small.

By providing an air gap between the third surface of the first optical system and the incident surface of the second optical system,
Since a large number of optical surfaces can be secured and the degree of freedom in optical design can be increased, it is possible to improve the optical performance of the image pickup optical system and further downsize it.

If light is formed as an intermediate image in the image pickup optical system (for example, a transparent body), the degree of freedom in layout is increased, and a subject image with a wide angle of view is sufficiently reduced and guided to the image pickup surface. In addition, the imaging optical system can be made compact even if the optical path length is considerably lengthened.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a display optical system that is a first embodiment of the present invention.

FIG. 2 is a display optical system (1) that is a second embodiment of the present invention.
Configuration diagram of.

FIG. 3 is a display optical system (2) according to a second embodiment of the present invention.
Configuration diagram of.

FIG. 4 is a configuration diagram of a display optical system that is a third embodiment of the present invention.

FIG. 5 is a configuration diagram of an image pickup optical system that is a fourth embodiment of the present invention.

FIG. 6 is a display optical system (1) which is a fifth embodiment of the present invention.
Configuration diagram of.

FIG. 7 is a configuration diagram of a modified example of the display optical system according to the fourth embodiment.

FIG. 8 is a configuration diagram of a modified example of the display optical system according to the fourth embodiment.

FIG. 9 is a configuration diagram of a display optical system that is a fifth embodiment of the present invention.

FIG. 10 is a sectional view of an optical system according to Numerical Example 1 of the present invention.

FIG. 11 is a sectional view of an optical system according to Numerical Example 2 of the present invention.

FIG. 12 is a sectional view of an optical system according to Numerical Example 3 of the present invention.

FIG. 13 is a sectional view of an optical system according to Numerical Example 4 of the present invention.

FIG. 14 is a sectional view of an optical system according to Numerical Example 5 of the present invention.

FIG. 15 is a configuration diagram of a conventional display optical system.

FIG. 16 is a block diagram of a conventional display optical system.

[Explanation of symbols]

30,30 ', 30 ", 130,230,330,43
0 first optical system 20, 20 ', 20 ", 120, 220 second optical system 10 image display element

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] December 19, 2002 (2002.12.
19)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

23. An image pickup apparatus comprising the image pickup optical system according to claim 22 .

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

Further, in order to further improve the optical performance as compared with the optical system proposed in Japanese Patent Laid-Open No. 10-153748, the internal reflection surface of the decentering prism is increased so that the intermediate image is formed only by the decentering prism. A type in which a second decentering prism is provided in the first decentering prism optical system, and the like in which the image is formed and the image is guided to an observer are disclosed in JP-A-2000-06.
6106, Japanese Patent Laid-Open No. 2000-105338,
JP 2000-131614 A, JP 2000-1
Japanese Patent No. 99853 and Japanese Patent Laid-Open No. 2000-227554.
And Japanese Patent Laid-Open No. 2000-231060.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0062

[Correction method] Change

[Correction content]

As described above, the light rays may be incident and reflected at a predetermined angle θ before and after the folding reflection surface 31c. However, it is preferable that the angle θ satisfies | θ | <30 °. If this condition is not satisfied, the first optical element 31 becomes large and it becomes difficult to make the entire optical system small, which is not preferable.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0067

[Correction method] Change

[Correction content]

(Third Embodiment) FIG. 4 shows a third embodiment of the present invention.
1 illustrates a display optical system that is an embodiment. To facilitate understanding, the first optical system is shown in a simplified manner. As the display optical system, the second optical system 20 shown in FIGS. 1 to 3 is used.
(20 ′, 20 ″) may be combined with each other.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0070

[Correction method] Change

[Correction content]

The light modulated and emitted by the image display element 10 enters the second optical system 120 through the incident surface 20a,
The second optical system 120 is emitted from the emission surface 20b, and the surface 32
It is incident on the first optical element 32 from a.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0076

[Correction method] Change

[Correction content]

(Fourth Embodiment) FIG. 5 shows a fourth embodiment of the present invention.
1 illustrates a display optical system that is an embodiment. To facilitate understanding, the first optical system is shown in a simplified manner. As the display optical system, the second optical system 20 shown in FIGS. 1 to 3 is used.
(20 ′, 20 ″) may be combined with each other.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0080

[Correction method] Change

[Correction content]

From the entrance surface 33a (third surface) to the optical element 3
The light incident on the light source 3 (first optical system 230) is reflected by the surface 33b.
The light is reflected by the (first surface), the optical element 33 is emitted from the surface 33c, and the reflection surface 34a (second surface) of the reflection mirror member 34 is formed.
Then, the light is reflected back from the surface 33c, is incident on the optical element 33 again from the surface 33c, and is reflected again on the surface 33b on the opposite side to the normal of the surface on the hit point. Is emitted through the optical element 33 and is guided to the eye E of the observer. A half mirror coating is applied to the surface 33a.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0086

[Correction method] Change

[Correction content]

(Fifth Embodiment) FIG. 6 shows a fifth embodiment of the present invention.
1 illustrates a display optical system that is an embodiment. To facilitate understanding, the first optical system is shown in a simplified manner. As the display optical system, the second optical system 20 shown in FIGS. 1 to 3 is used.
(20 ′, 20 ″) may be combined with each other.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0108

[Correction method] Change

[Correction content]

[0108] In this embodiment, an air layer (air gap) provided between the exit surface 26 a of the first entrance surface of the optical element 37 (third surface) 37a and the second optical element 26 However, the first optical element 37 and the second optical element 26 are placed in a portion other than the incident surface 37a of the first optical element 37 and the exit surface 26a of the second optical element 26 (outside the light ray effective range). It is configured to be in contact with each other.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Name of item to be corrected] 0123

[Correction method] Change

[Correction content]

The numerical value next to FFS in the TYP column is the aspherical coefficient whose surface shape is shown at the bottom of the table.
It shows that the shape is a rotationally asymmetrical shape corresponding to ci (i = 1, 2, 3 ...).

[Procedure Amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0124

[Correction method] Change

[Correction content]

Nd and νd (in the table, referred to as vd) respectively indicate the refractive index and the Abbe number at the d-line wavelength of the medium after that surface, and the change in the sign of the refractive index N d is the surface. Indicates that the light is reflected at. When the medium is an air layer, only the refractive index Nd is shown as 1.000 and the Abbe number νd is omitted.

[Procedure Amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0150

[Correction method] Change

[Correction content]

The optical system of this numerical example may be used as an image pickup optical system. In this case, the light from the object point at the infinity in the negative direction of the z-axis passes through the stop S1 and the first optical element 32.
Be led to. Then, the light enters the first optical element 32 from S2, is reflected at S3, is reflected at S4, is reflected at S5, and is reflected at S5.
After being reflected back at 6, the light is reflected at S7, reflected at S8, emitted from the first optical element 32 at S9, and guided to the second optical element 21 . The light guided to the second optical element 21 forms an image on the imaging surface SI via S10, S11, and S12.

[Procedure Amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0175

[Correction method] Change

[Correction content]

By taking such an optical path, the first
Since the light beam substantially reciprocates between the first surface and the second surface, it is possible to effectively utilize the space in the first optical system and obtain the optical path length. Moreover, a small optical system can be realized even if the optical path length is long.

[Procedure Amendment 14]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 11

[Correction method] Change

[Correction content]

FIG. 11

[Procedure Amendment 15]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 14

[Correction method] Change

[Correction content]

FIG. 14

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03B 21/00 G03B 21/00 G 21/14 21/14 Z H04N 5/64 511 H04N 5/64 511A ( 72) Inventor Tomomi Matsunaga 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kazutaka Inoguchi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Invention Person Hideki Morishima 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F-term (reference) 2H087 KA03 KA06 KA23 RA41 TA01 TA02 TA06

Claims (42)

[Claims] 1. A display optical system for guiding light from an original image to an observer's eye or a projection surface, comprising a first optical system having at least three surfaces, the first optical system comprising: At least a first surface having a reflecting action, a second surface that reflects the light reflected by the first surface toward the first surface again, and a light from the original image are transmitted to be incident on the first optical system. And has a third surface that reflects the light reflected from the second surface back to the first surface and guides it to the observer's eye or the projected surface, and the light from the original image is the third surface. Of the second optical system, and the third surface and the exit surface of the second optical system are arranged with an air space between them and are incident on the first surface again. A display characterized in that the central angle of view chief ray is reflected on the side opposite to the previous side with respect to the normal of the surface on the hit point and advances. Manabu system. 2. The first optical system reflects the light, which is transmitted through the third surface and is incident, on the first surface,
The surface is reflected by the first surface, the first surface is reflected, the third surface is reflected, and the first surface is transmitted and guided to the observer's eye or the surface to be illuminated. 1. The display optical system described in 1. 3. The first optical system reflects the light, which is transmitted through the third surface and is incident, on the first surface,
Reflected by the surface, reflected by the first surface, reflected by the second surface, reflected by the first surface, reflected by the third surface, transmitted through the first surface The display optical system according to claim 1, wherein the display optical system is guided to an observer's eye or a surface to be illuminated. 4. The display optical system according to claim 1, wherein an intermediate image of the original image is formed in the first optical system. 5. The display optical system according to claim 1, wherein each of the first and second optical systems has a positive optical power as a whole. 6. The third surface and the exit surface of the second optical system are surfaces that are convex toward each other, and the third surface and the exit surface of the second optical system are convex surfaces toward each other. Display optics. 7. The method according to claim 1, wherein at least one of the first to third surfaces has a curvature.
The display optical system according to any one of 1. 8. The display optical system according to claim 1, wherein at least one of the first to third surfaces is eccentric with respect to an incident light beam. 9. At least one of the first to third surfaces is a rotationally asymmetric surface.
9. The display optical system according to any one of items 1 to 8. 10. The display optical system according to claim 1, wherein the first to third surfaces are formed on a transparent body. 11. The first and third surfaces are formed on a transparent body, and the second surface is constituted by a reflecting member, according to any one of claims 1 to 9. The display optical system according to item. 12. The display optical system according to claim 11, wherein the reflecting surface of the reflecting member has a curvature and is decentered with respect to an incident light beam. 13. The display optical system according to claim 11, wherein the reflecting member is a rear surface mirror. 14. The light is totally reflected on any of the surfaces formed on the transparent body.
3. The display optical system according to any one of 3 above. 15. The display optical system according to claim 1, wherein the second optical system includes only a refracting surface. 16. The optical system according to claim 1, wherein the second optical system includes a refracting surface and a reflecting surface.
The display optical system according to any one of 1. 17. The display optical system according to claim 1, wherein an optical surface of the second optical system includes a rotationally asymmetric surface. 18. The display optical system according to claim 1, wherein the second optical system includes a concave lens. 19. The first and second optical systems each include a transparent body, and the transparent bodies are made of materials having the same refractive index. 19. The display optical system according to any one of items 1 to 18. 20. The optical member having the third surface of the first optical system and the optical member having the exit surface of the second optical system are in contact with each other outside a light ray effective range. The display optical system according to any one of claims 1 to 19. 21. An image display device comprising the display optical system according to any one of claims 1 to 20. 22. An imaging optical system for guiding light from a subject to an imaging surface, comprising: a first optical system having at least three surfaces, the first optical system having at least a reflecting action. A first surface, a second surface that reflects the light reflected by the first surface toward the first surface again, and a second surface that reflects the light that has entered the first optical system from the subject. A second optical system that guides the light emitted from the third surface to the image pickup surface, and has a third surface that transmits the light reflected back from the first surface to the image pickup surface side. , The third surface and the incident surface of the second optical system are arranged with an air gap, and the central angle-of-view chief ray incident on the first surface again is at the hit point. An imaging optical system that is characterized in that it advances toward the side opposite to the previous side with respect to the normal line of the surface. 23. The first optical system reflects the light incident through the first surface on the third surface, reflects the light on the first surface, and reflects the light on the second surface. 23. The image pickup optical system according to claim 22, wherein the image pickup optical system is reflected by the first surface, is reflected by the first surface, and is transmitted by the third surface. 24. The first optical system reflects the light, which is transmitted through the first surface and is incident, on the third surface,
Reflecting on the surface, reflecting on the second surface, reflecting on the first surface, reflecting on the second surface, reflecting on the first surface, and transmitting through the third surface. The imaging optical system according to claim 22. 25. An intermediate image of the subject is formed in an optical path from the light from the subject entering the first optical system to the exit from the second optical system. The imaging optical system according to any one of claims 22 to 24. 26. The image pickup optical system according to claim 22, wherein each of the first and second optical systems has a positive optical power as a whole. 27. The method according to claim 22, wherein the third surface and the incident surface of the second optical system are surfaces that are convex toward each other. Imaging optical system. 28. The image pickup optical system according to claim 22, wherein at least one of the first to third surfaces has a curvature. 29. The image pickup optical system according to claim 22, wherein at least one of the first to third surfaces is decentered with respect to an incident light ray. 30. At least one of the first to third surfaces is a rotationally symmetric surface.
The imaging optical system according to any one of 2 to 29. 31. The image pickup optical system according to claim 22, wherein the first to third surfaces are formed on a transparent body. 32. The first and third surfaces are formed on a transparent body, and the second surface is constituted by a reflecting member, according to any one of claims 22 to 30. The imaging optical system according to the item. 33. The imaging optical system according to claim 32, wherein the reflecting surface of the reflecting member has a curvature and is decentered with respect to an incident light beam. 34. The image pickup optical system according to claim 32, wherein the reflecting member is a rear surface mirror. 35. The light is totally reflected by any one of the surfaces formed on the transparent body.
The imaging optical system according to any one of 4 above. 36. The image pickup optical system according to claim 22, wherein the second optical system is composed of only a refracting surface. 37. The method according to claim 22, wherein the second optical system is composed of a refracting surface and a reflecting surface.
The imaging optical system according to any one of 5 above. 38. The image pickup optical system according to claim 22, wherein an optical surface of the second optical system includes a rotationally asymmetric surface. 39. The image pickup optical system according to claim 22, wherein the second optical system includes a concave lens. 40. The first and second optical systems are each configured to include a transparent body, and the transparent bodies are formed of materials having the same refractive index. 40. The image pickup optical system according to any one of items 39 to 39. 41. The optical member having the third surface of the first optical system and the optical member having the incident surface of the second optical system are in contact with each other outside the effective light ray range. The imaging optical system according to any one of claims 22 to 40. 42. An image pickup apparatus comprising the image pickup optical system according to claim 22.