JP2003066365A - Optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively utilize a space by simplifying the structure of a free- form surface prism. SOLUTION: A mounting part 23 for fixing an element is formed in a bridge girder shape at both sides of a first optical surface 21a of a free-form surface prism 21, a boss 23a to be positioning when attached to a housing is provided projectingly, and a screw insertion hole 23b is also bored at an end part projecting toward a second optical surface 21b. In assembling these parts, positioning is performed by engaging and inserting the bosses 23a provided projectingly on the mounting parts 23 for fixing an element with/into recessed parts for positioning provided in the housing, and screws inserted into the screw insertion holes 23b are subsequently screwed into the housing to fix the free-form surface prism 21 to the housing. Space can be effectively utilized because the end parts of the mounting parts 23 are prevented from projecting toward side faces 21d that do not contribute to optical action.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an optical element for enlarging an image displayed on an image display element.

[0002]

2. Description of the Related Art Generally, in order to obtain good optical performance as an optical device using an optical element such as a prism, it is necessary to position and fix the optical element with high precision in a housing or other optical elements. is there.

An optical prism is a typical example of this optical element. Since this optical prism has few reference planes, various fixing methods have been conventionally proposed.

For example, the optical prism 1 shown in FIG.
A flange portion 1a is provided so as to project from two opposing surfaces that do not contribute to the optical action of the optical prism 1.
A screw insertion hole 1b is formed in the base plate, and a positioning pin 1c is provided on the rear surface.

On the other hand, the housing 2 in which the optical prism 1 is fixedly provided is provided with a joint surface 2a with which the flange portion 1a provided on the optical prism 1 abuts, and the screw insertion hole 1b of the joint surface 2a is provided. A screw hole 2b is screwed at a corresponding position, and a positioning recess 2c into which the positioning pin 1c is inserted is bored.

At the time of assembly, the back surfaces of the flange portions 1a projecting on both side surfaces of the optical prism 1 are brought into contact with the joint surfaces 2a provided on the housing 2 so as to project on the back surfaces of the flange portions 1a. The positioning pin 1c is inserted into the positioning recess 2c formed in the joint surface 2a to position the optical prism 1 in the housing 2, and the screw 3 inserted into the screw insertion hole 1b is attached to the joint surface 2a. The optical prism 1 is fixed to the housing 2 by being screwed into the screw hole 2b that is screwed.

In this case, as shown in FIGS. 32 and 33,
The flange portion 1a is cut to a position where the screw insertion hole 1b is halved, and on the other hand, a protruding portion 2d slightly lower than the plate thickness of the flange portion 1a is provided on the outer surface of the joint surface 2a of the housing 2. You may do it.

That is, in the configuration shown in FIGS. 32 and 33, when the flange portions 1a protruding on both sides of the optical prism 1 are fitted between the protrusion portions 2d of the housing 2, the flange portion 1a is inserted into the flange portion 1a. Half-threaded screw insertion hole 1b
A circular screw insertion hole is formed by the half-shaped screw insertion hole 2e formed on the inner surface of the protrusion 2d, and the screw 3 inserted through the screw insertion hole is screwed into the joint surface 2a of the housing 2. The optical prism 1 is screwed into the provided screw hole 2b to mount the optical prism 1 on the housing 2
Fixed to.

As described above, in FIGS. 32 and 33, since the flange portion 1a is formed in half, the shape of the flange portion 1a can be made smaller than that of the free curved surface prism 1 shown in FIG. Further, when the screw 3 is screwed, the screw head comes into contact with the protrusion 2d on the housing 2 side, and further tightening is prevented, so that the generation of internal stress on the optical prism 1 is suppressed, and the optical prism 1 is prevented. Can be prevented from being deformed.

Further, as shown in FIG. 34, a screw hole 2f is screwed on the side surface of the housing 2 and the side surface of the optical prism 1 is pressed by the tip of the set screw 3 screwed into the screw hole 2f. A technique of fixing the optical prism 1 to the housing 2 is also known.

According to this technique, it is not necessary to form a screw insertion hole for screwing in the flange portion 1a of the optical prism 1, so that the shape of the flange portion 1a can be further reduced. As a result, it is possible to reduce the size of the housing 2 that holds it, and thus to reduce the size of the entire device.

In this case, as shown in FIG. 35, a plate member 4 bent in a U-shape is inserted into the inner surface of the housing 2 and the side surface of the optical prism 1 is set via the side surface 4 a of the plate member 4. By pressing with the screw 3, the tip of the set screw 3 does not directly press the side surface of the optical prism 1, so that the internal stress generated in the optical prism 1 can be suppressed.

On the other hand, as shown in FIG. 36, the set screw 3
Is a sword set screw (3), a V groove 1d into which the tip of the sword set screw 3 is engaged is formed on the side surface of the optical prism 1, and the sword set screw 3 is screwed to the housing 2. Hole 2
By screwing into the f, the tip of the sword set screw 3 abuts on the slope of the V groove 1d formed on the side surface of the optical prism 1, and when further screwing in, the optical prism 1 is pulled in the abutting surface direction. It can be pressed and fixed to the housing 2. Reference numeral 2g is a pin which is inserted into a guide hole formed in the flange portion 1a and regulates the movement of the optical prism 1 in the width direction.

Further, as shown in FIG. 37, the optical prism 1
There is also known a technique in which an elastic fixing member 5 such as a spring is interposed between both side surfaces of and the inner surface of the housing 2.

According to this technique, the pressing force for fixing the optical prism 1 becomes constant, and the elastic fixing member 5 is elastically deformable even when the optical prism 1 expands or contracts due to a temperature change or the like. It is possible to prevent the generation of internal stress and prevent damage to the optical prism 1.

Also, an optical prism 11 as shown in FIG.
Is also known. The optical prism 11 is disclosed in, for example, Japanese Patent Laid-Open No. 9-73005. The optical prism 11 shown in the figure is used for an image observing device such as a head mounted display (HMD) that magnifies and observes an image displayed on a small image display element, and has a flat or curved light incidence. First optical surface 11a for use, a second optical surface 11b formed of a flat surface or a curved surface for totally reflecting the light beam incident on the element from the first optical surface 11a, and a light beam from the second optical surface 11b. A third optical surface 11c that reflects at least a part to the second optical surface 11b side,
Except for the first to third optical surfaces 11a to 11c, there are two flanges 11d for optical positioning, which are opposed to each other and do not perform optical action.
There is disclosed a technique in which the optical prism 11 is held via the d, and the optical prism 11 is held accurately without causing optical distortion.

[0017]

However, the above-mentioned conventional techniques have the following problems.

Optical prisms 1, 1 shown in FIGS. 31 and 38
1 is a flange portion 1b on the side surface of the optical prism 1, 11.
Since 11d is provided in a protruding manner, the dimension in the Y direction shown in the figure becomes large, which is an obstacle to realizing the miniaturization of the entire apparatus.

Further, the optical prism 1 shown in FIGS. 32 and 33.
Can restrain the fastening force at the time of screwing to a certain extent by the protrusion 2d formed on the housing 2 to prevent an unreasonable force from acting on the optical prism 1, but it should be completely prevented. It is difficult. As a result, if the dimensions, settings, and assembly conditions of each member are incorrect, the optical prism 1 is distorted,
There is an inconvenience that deterioration of optical performance is accelerated.

On the other hand, in each of the optical prisms 1 shown in FIGS. 34 to 36, the set screw 3 is used to fix the optical prism 1 to the housing 2 by directly pressing the side surface of the optical prism 1. However, the fastening force of the set screw 3 tends to cause an internal stress in the optical prism 1, which causes a problem that the optical performance is deteriorated. Further, since the optical prism 1 and the housing 2 have different expansion coefficients, there is a disadvantage that distortion is likely to occur when the optical prism 1 and the housing 2 are affected by a temperature change, and the optical performance is deteriorated.

In the optical prism 1 shown in FIG. 37, the elasticity of the elastic fixing member 5 fixes the side surface of the optical prism 1 to the inner surface of the housing. The influence due to the difference in expansion coefficient can be absorbed by the elastic deformation of the elastic fixing member 5, so that it is hardly affected by the temperature change, but when an external force such as vibration or impact is applied to the optical prism 1, There is a disadvantage that the elastic fixing member 5 is plastically deformed and the position of the optical prism 1 is easily displaced.

The present invention has been made in view of the above problems, and by effectively utilizing the space between the optical element and the housing, the overall size of the apparatus is reduced, and optically harmful distortion is generated. It is an object of the present invention to provide an optical element that can be fixed to a housing without causing it.

[0023]

In order to achieve the above object, the first optical element according to the present invention is an optical element for enlarging an image displayed on a small image display element, and is provided on the display surface of the image display element. A first optical surface which is substantially opposed to and captures an image, and a second optical surface which reflects a light ray incident from the first optical surface inside the element and finally emits a magnified image light ray to an eyeball of an observer. And one or more reflective optical surfaces that contribute to internal reflection at least once so that incident light from the first optical surface reaches the second optical surface, and side surfaces that do not contribute to optical action. In addition, an element fixing attachment portion is provided on any of the first and second optical surfaces and the reflection optical surface.

The second optical element is an optical element for enlarging an image displayed on a small-sized image display element, and a first optical surface which substantially opposes a display surface of the image display element to capture an image, and the first optical surface. The second optical surface that reflects the light ray incident from the first optical surface inside the element and finally emits a magnified image light ray to the eyeball of the observer, and the incident light from the first optical surface is the first optical surface. 2 has at least one reflection optical surface that contributes to the inside at least once so as to reach the optical surface 2, and a side surface that does not contribute to an optical action, and further includes an element fixing attachment portion, The mounting portion is characterized in that it is separated from the element by a groove formed in any two or more of the surfaces forming the element.

In this case, preferably 1) the first and second
At least one of the optical surface and the reflective optical surface has a shape symmetrical with respect to only one target surface.

2) The element fixing attachment portion is provided on a spacer portion formed in a cylindrical shape from the first optical surface toward the image display element.

3) At least a part of the spacer portion forms a guide portion in a direction substantially parallel to the optical axis incident on the first optical surface, and an element holding member for holding the image display element is the guide. It is characterized in that it is movable along the section.

4) The element fixing mounting portion is formed on a surface parallel or orthogonal to the optical axis incident on the first optical surface.

5) The device fixing mounting portion is formed on a surface parallel or orthogonal to the optical axis emitted from the second optical surface.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration diagram of an image observing apparatus, and FIG. 2 is a configuration diagram of a free-form surface prism. Reference numeral 21 in the figure is a free-form surface prism as an optical element injection-molded from a resin material, which is a first light-incident surface.
Optical surface 21a, a second optical surface 21b that partially acts as a reflection and refraction and transmission surface using total reflection, and a reflective optical surface 21c that is a third optical surface that performs semi-transmission or reflection are optically as a whole. Three optical surfaces 21a to 21c that operate
And a pair of side surfaces 2 facing each other that do not contribute to the optical action.
1d and. Here, the optical surfaces 21a to 21c are planes, spherical surfaces, aspherical surfaces, aspherical surfaces that are plane-symmetrical with respect to only one plane of symmetry, and the like.

The display surface of the small-sized image display element 22 is substantially opposed to the first optical surface 21a. When the image displayed on the image display element 22 is taken into the element from the first optical surface 21a of the free-form surface prism 21, the light flux based on this image is totally reflected by the second optical surface 21b. After that, the light is reflected and condensed by the reflective optical surface 21c, transmitted through the second optical surface 21b, and guided to the eyeball Uey of the observer.

At this time, due to the curvatures of the second optical surface 21b and the reflective optical surface 21c, the virtual image magnified in front of the observer is formed without forming the image displayed on the image display element 22 on the way. Display it.

The image display element 22 may be an EL (Electronic Luminescent) element, a plasma display, an LED (Light Emitting Diode) array, etc. in addition to the liquid crystal display element. In the case of adopting, the illumination element 22a for observing the image displayed on the liquid crystal display element with sufficient brightness is provided on the back surface thereof.

As another embodiment, like the free-form surface prism 21 'shown in FIG. 3, the light flux introduced into the inside of the element from the first optical surface 21a is the reflecting surface 21c which is the third optical surface.
To the fourth optical surface which is once reflected by the reflecting surface 21c, is totally reflected by the second optical surface 21b, and is further connected to the reflecting surface 21c which is the third optical surface, and has another defining surface. After the light is reflected and condensed by the barrel reflection optical surface 21c ′, the second
The light may be guided from the optical surface 21b to the eyeball Uey of the observer.

By the way, as shown by hatching in FIG. 2B, the effective luminous flux range on the first optical surface 21a is the same as the second optical surface 21b shown by hatching in FIG.
It is narrower than the effective light flux range of the reflection optical surface 21c shown by hatching in (d), and therefore, the entire prism width determined by the effective light flux ranges of the second optical surface 21b and the reflection optical surface 21c is used. is not. This also applies to the free-form surface prism 21 'according to another embodiment shown in FIG.

Therefore, despite such an optical surface,
In the area where the light flux does not actually pass, that is, in the area outside the effective light flux range shown by hatching in FIG. 2 (hereinafter referred to as “ineffective light flux range”), the element fixing mounting portion (hereinafter “mounting portion”)
Is provided, it is possible to effectively use the space between the free-form curved surface prism 21 and the housing in which the free-form surface curved prism 21 is fixed.

Hereinafter, a mode in which the mounting portion is provided in the invalid light flux range of the free-form surface prism 21 will be described for each embodiment with reference to the drawings of FIGS. 4 to 30.

Here, the outline of each embodiment will be described. In the first to ninth embodiments shown in FIGS. 4 to 15,
A mode in which a mounting portion is formed in the invalid light flux range of the first optical surface 21a of the free-form surface prism 21 is shown.

The tenth to sixteenth parts shown in FIGS.
The embodiment shows a mode in which a mounting portion is provided on the surface extended from the ineffective light flux range of the first optical surface 21a.

The seventeenth and eighteenth parts shown in FIGS.
The embodiment shows a mode in which the mounting portion is provided in the invalid light flux range of the second optical surface 21b or the reflective optical surface 21c.

First, the first embodiment of the present invention will be described with reference to FIG. In the present embodiment, both side surfaces 21 of the first optical surface 21a of the free-form surface prism 21 are formed.
In the invalid light flux range on the d side, mutually parallel mounting portions 23 are integrally formed in a bridge girder shape, and both ends thereof are projected to the second optical surface 21b side and the reflective optical surface 21c side.

Further, a boss 23a, which is engaged and positioned in a positioning recess formed on a mounting surface of a casing (not shown), is provided to project from both of the mounting portions 23, and the mounting portion 23 has A screw insertion hole 23b is formed in the tip portion protruding toward the second optical surface 21b.
A screw hole (not shown) is formed in the mounting surface of the housing corresponding to the screw insertion hole 23b. Further, the alternate long and short dash line in the figure indicates the eyeball Uey of the observer from the image display element 22.
It shows the optical axis leading to, and is common to the drawings starting from FIG.

According to this structure, the mounting portions 23 formed in the shape of bridge girders on both sides of the first optical surface 21a of the free-form surface prism 21 are mounted on the mounting surface (not shown) of the housing. At this time, the boss 2 protruding from the mounting portion 23
3a is inserted into a positioning recess formed in the surface to be mounted and positioned, and then a screw insertion hole is formed in the tip of the mounting portion 23 protruding toward the second optical surface 21b. The free curved surface prism 21 is fixed to the housing by screwing a screw inserted into the hole 23b from the lower side of the drawing into a screw hole that is screwed on the mounting surface.

As described above, in the present embodiment, since the mounting portion 23 is formed in the ineffective light flux range on the both side surfaces 21d side of the first optical surface 21a, the optical function is not hindered. Further, both ends of the mounting portion 23 are projected toward the second optical surface 21b and the reflective optical surface 21c side, and are not projected toward the side surface 21d side.
It is possible to effectively use the space between the housings where this is fixed.

In this case, the screw insertion hole 23b may be formed on the tip end side of the mounting portion 23 projecting to the reflection optical surface 21c side, or each optical surface 21b,
It may be formed on both ends of the protrusion 21c. Of course, each screw insertion hole 23 on the mounting surface of the housing
It is assumed that a screw hole is bored in a portion corresponding to b.

FIG. 5 shows a perspective view of a free-form surface prism according to the second embodiment of the present invention. In the first embodiment, both end portions of the mounting portion 23 have the optical surfaces 21b and 21c.
Although it is projected from the mounting portion 2 in the present embodiment,
3 is projected only from the second optical surface 21b side, and a screw insertion hole 23b is bored in the protruding tip portion.

Since the mounting portion 23 is projected only from the second optical surface 21b side, it is possible to further reduce the sizes of both the free-form surface prism 21 and the housing in which the free-form surface prism 21 is fixedly mounted. You can

FIG. 6 shows a perspective view of a free-form surface prism according to the third embodiment of the present invention. In the above-described second embodiment, the mounting portion 23 is projected to the second optical surface 21b side. However, in the present embodiment, the mounting portion 23 is projected only from the reflective optical surface 21c side and the tip portion thereof is provided. Since the screw insertion hole 23b is formed, the same effect as that of the second embodiment can be obtained.

FIG. 7 shows a perspective view of a free-form surface prism according to the fourth embodiment of the present invention. In the above-described first embodiment (see FIG. 5), the mounting portion 23 is attached to the first optical surface 21.
Although it is arranged substantially parallel to a, in the present embodiment, the mounting portion 23 is tilted in a direction orthogonal to the optical axis incident on the first optical surface 21a.

By making the mounting portion 23 orthogonal to the optical axis incident on the first optical surface 21a, the mounting portion 23 and the image display element 22 become parallel to each other, so that the free-form surface prism 21 and the image display element 22. When it is attempted to fix and to be fixed at optically correct positions via a common connecting member, the shape of this connecting member can be simplified. In this case,
The mounting portion 23 may be parallel to the optical axis incident on the first optical surface 21a.

FIG. 8 shows a perspective view of a free-form surface prism according to the fifth embodiment of the present invention. In the above-described fifth embodiment. Although the mounting portions 23 are arranged in a bridge girder shape on both sides of the first optical surface 21 a, in the present embodiment, the mounting portions 23 are arranged.
Is formed at a position one step lower on both sides of the first optical surface 21a, and the effect is the same as that of the fifth embodiment.

FIG. 9 shows a perspective view of a free-form surface prism according to the sixth embodiment of the present invention. In this embodiment,
A pair of mounting portions 23 that are parallel to each other extend upward in the figure from both ridges on the reflective optical surface 21c side within the invalid light flux range formed on both sides of the first optical surface 21a of the free-form surface prism 21. In addition, a boss 23a is provided on the rear surface (on the side of the reflective optical surface 21c) of the mounting portion 23.

In such a structure, the back surface (the reflection optical surface 21c side) of the mounting portion 23 of the free-form curved surface prism 21 is brought into contact with the mounting surface of the housing (not shown), and the boss protruding from the mounting portion 23 is provided. 23a is inserted into the positioning recess formed on the mounting surface and positioned, and then the screw inserted into the screw insertion hole 23b is screwed into the screw hole screwed on the mounting surface of the housing. Free-form surface prism 2
1 is fixed to the housing.

When the mounting surface of the housing faces the front surface side (second optical surface 21b side) of the mounting portion 23 of the free-form surface prism 21, the boss 23a is mounted on the mounting portion 2.
3 is provided so as to project from the front surface side of the housing 3, the front surface of the mounting portion 23 is brought into contact with the mounting surface of the housing for positioning, and is fixed to the screw insertion hole 23b by a screw inserted from the rear surface.

As described above, according to the present embodiment, the mounting portion 23 is attached to the first optical surface 21a of the free-form surface prism 21.
Since it is formed so as to extend upward from the drawing, the mounting portion 23 of the free-form curved surface prism 21 has the second optical surface 21.
The space can be effectively used without protruding outward from the b, the reflection optical surface 21c, or the side surface 21d. As a result, it is possible to reduce the size of the entire device including the housing in which the free-form surface prism 21 is fixedly installed.

In the above-described first to sixth embodiments, for example, the screw insertion hole 2 formed in the mounting portion 23, for example.
3b may be cut in half like the screw insertion hole 1b shown in FIG. Further, instead of the boss 23a, a positioning fitting hole portion may be formed, and a boss that fits into this positioning fitting hole portion may be provided on the mounting surface on the housing side.

10 and 11 show a seventh embodiment of the present invention. Here, FIG. 10 is a perspective view of the free-form curved prism, and FIG. 11 is a partial cross-sectional front view of the free-form curved prism fixed to the housing.

In this embodiment, the free-form surface prism 21 is used.
The first groove as a groove on the boundary line between the ineffective light flux range and the effective light flux range (see FIG. 2B) formed on both sides of the first optical surface 21a of the first optical surface 21a.
The slit 21e of the first side 21d
On the optical surface 21a side of the second slit 21f as a groove.
The slits 21e and 21f form the mounting portion 23 separately on the ridge portion formed by the first optical surface 21a and the side surface 21d of the free-form surface prism 21. The slits 21e and 21f may be formed when the free-form surface prism 21 is injection molded.

Further, the first optical surface 21 of the mounting portion 23
A boss 23a is provided on the a side, and the screw hole 23
c is screwed.

On the other hand, on the mounting surfaces 24a formed on both sides of the housing 24 in which the free-form curved surface prism 21 is fixedly mounted,
A positioning recess (not shown) for fitting the boss 23a is formed, and a screw insertion hole 24b is formed at a position corresponding to the screw hole 23c.

In such a structure, the free-form surface prism 2
When the mounting portion 23 provided in 1 is brought into contact with the mounted surface 24a provided in the housing 24, the boss 23a protruding from the mounting portion 23 is formed in the mounted surface 24a of the housing 24. It is positioned by fitting it into a positioning recess (not shown).

Next, the screw 3 inserted in the screw insertion hole 24b formed in the housing 24 is screwed into the screw hole 23c, and the free-form curved surface prism 21 is positioned and fixed to the housing 24.

As described above, in the present embodiment, since the mounting portion 23 is formed separately by forming the slits 21e and 21f in the free-form curved surface prism 21, no protruding portion is formed in the free-form curved surface prism 21 and the space is reduced. Can be effectively used, and the entire apparatus including the housing 24 can be downsized.

The mounting portion 23 is attached to the free-form surface prism 2
Since the main body 1 is separated via the slits 21e and 21f, the screw 3 is not directly observed by the observer through the second optical surface 21b, and the product quality can be maintained.

Further, since the slits 21e and 21f absorb the distortion generated when the mounting portion 23 is fixed to the mounting surface 24a of the housing 24, internal stress is not generated in the free-form curved surface prism 21, and the Performance can be guaranteed in the long run.

Further, FIGS. 12 and 13 show an eighth embodiment of the present invention. Here, FIG. 12 is a perspective view of the free-form curved prism, and FIG. 13 is a partial cross-sectional front view of the free-form curved prism fixed to the housing.

In the present embodiment, the free-form surface prism 21
The first counterbore groove is formed on the boundary line between the ineffective light flux range and the effective light flux range (see FIG. 2B) formed on both sides of the first optical surface 21a, or on the ineffective light flux range side of the boundary line. 21g is formed and the first optical surface 2 of the side surface 21d is formed.
A second counterbore groove 21h is formed on the side of 1a, and both counterbore grooves 21g and 21h are made to communicate in the free-form curved surface prism 21. In addition, these counterbores 21g, 21h
May be formed when the free-form surface prism 21 is injection molded.

On the other hand, on the mounting surfaces 24a formed on both sides of the housing 24 in which the free-form curved surface prism 21 is fixedly mounted,
Engage from the first counterbore groove 21g to the second counterbore groove 2
A locking claw portion 24c that engages with 1h is formed.

In such a configuration, the locking claw portions 24c formed on the mounting surface 24a of the housing 24 are formed on both sides of the first optical surface 21a of the free-form surface prism 21. Engage in the counterbore groove 21g and set the claw at the tip to the second position.
When hooked on the edge of the countersunk groove 21h, the mounting portion 23 is sandwiched by the claw portion formed at the tip of the locking claw portion 24c and the projection 24d formed on the mounting surface 24a.
The free curved surface prism 21 is fixed to the housing 24.

In this case, the housing 24 and the free-form surface prism 2
The positioning with respect to No. 1 is performed by forming a boss on one of the mounting portion 23 provided on the free-form curved surface prism 21 and the mounting surface 24a provided on the housing 24, and forming a positioning recess on the other. This is done by fitting with the recess for use. Alternatively, positioning may be performed by fitting the locking claw portion 24c and the first counterbore groove 21g. Alternatively, an abutting surface may be separately formed on at least one of the attachment portion 23 provided on the free-form surface prism 21 and the attached surface 24a provided on the housing 24, and the abutting surface may be used for positioning.

As described above, according to the present embodiment, the housing 24 and the free-form curved surface prism 21 can be connected and fixed to each other with one touch, so that the assembly is facilitated and the number of manufacturing steps can be reduced. In addition, since a fastening member such as a screw is not required at the time of assembly, the number of parts can be reduced. Furthermore, since the fastening member is not required, torque management at the time of fastening is not required, and the efficiency of assembly work can be realized.

Further, FIGS. 14 and 15 show a ninth embodiment of the present invention. Here, FIG. 14 is a perspective view of the free-form curved prism, and FIG. 15 is a partial cross-sectional front view of the free-form curved prism fixed to the housing.

In this embodiment, the free-form surface prism 21
A slit as a groove on the boundary line between the ineffective light flux range and the effective light flux range (see FIG. 2 (b)) formed on both sides of the first optical surface 21a, or slightly on the invalid light flux range side of this boundary line. 21j is formed, and the deepest part of this slit 21j is cut and formed in an L shape in the direction of the side surface 21d.

The slit 21j is formed when the free-form surface prism 21 is injection-molded. The mold used for this injection molding is the second optical surface 21 of the free-form surface prism 21.
The slit 21j is formed so as to be divided in the direction of b and the reflective optical surface 21c, and the slit 21j is formed along the dividing direction.

The structure of the housing 24 in which the free-form surface prism 21 is mounted is similar to that of the eighth embodiment described above, and the description thereof will be omitted.

In this structure, since the slit 21j is formed in the mold splitting direction of the molding die, the mounting portion 23 can be formed with high precision without complicating the shape of the free-form surface prism 21. Become.

FIG. 16 is a perspective view of the free-form surface prism according to the tenth embodiment of the present invention.

Free-form surface prism 25 shown in this embodiment
Forms flange portions 25a and 25b from the first optical surface 21a toward the second optical surface 21b and the reflective optical surface 21c, and the effective light flux range of the first optical surface 21a (see FIG. 2B).
(Refer to FIG. 3), an ineffective light flux range is formed, and a cylindrical spacer portion 26 extending in the direction of the image display element 22 is integrally formed from the ineffective light flux range. 22 is directly fixed.

According to such a configuration, the image display element 2
Since 2 is directly attached to the spacer portion 26 formed integrally with the free-form surface prism 25, the positional relationship between the image display element 22 and the first optical surface 21a of the free-form surface prism 25 is always constant. Therefore, good optical characteristics can be obtained.

Further, since the space from the image display element 22 to the first optical surface 21a is substantially sealed by the spacer portion 26 formed in a cylindrical shape, it is possible to prevent dust from entering and adhering to this space. it can.

In this case, the flange portions 25a, 25b
May be formed in parallel with the optical axis emitted from the second optical surface 21b. This makes it easy to adjust the position during assembly.

FIG. 17 is a perspective view of the free-form surface prism according to the eleventh embodiment of the present invention. The present embodiment is a modification of the tenth embodiment described above, and shows a mode in which a mounting portion 27 is formed on the spacer portion 26.

The mounting portion 27 has the first optical surface 21a.
Is formed on the end surface of the flange portion 25b extending from the side toward the reflection optical surface 21c side.
a is screwed.

With such a structure, the mounting portion 2 formed on the free-form curved surface prism 25 with respect to the casing (not shown)
7 is abutted, and a screw inserted through a screw insertion hole formed in the housing is screwed into the mounting portion 27 in a screw hole 27a.
And the free-form curved surface prism 25 is fixed to the housing.

In this case, as shown in FIG. 18, by making the mounting portion 27 a plane orthogonal to the optical axis emitted from the second optical surface 21b, the housing 24 can be positioned with respect to the mounted surface 24a. It will be easier.

Further, FIGS. 19 and 20 show a twelfth embodiment of the present invention. Here, FIG. 19 is a perspective view of the free-form surface prism, and FIG. 20 is a cross-sectional view of the free-form surface prism. The present embodiment is a modification of the eleventh embodiment described above, in which positioning pins 26a and 27b are projectingly provided on the end surface of the cylindrical spacer portion 26 and the mounting portion 27.

A fitting hole 28a is formed at a position corresponding to the positioning pin 26a of the element holding member 28 to which the image display element 22 is fixed in advance, while the mounting portion 25c abuts on the fitting hole 28a. A fitting hole 24e is formed in a position on the mounting surface 24a of the housing 24 corresponding to the positioning pin 27b.

According to this structure, the image display element 2
The fitting hole portion 28a formed in the element holding member 28 for preliminarily fixing 2 is assembled to the positioning pin 26a protruding from the end surface of the spacer portion 26 integrally formed with the free-form surface prism 25. Then, the element holding member 28 is positioned. After that, the positioning pin 26 a protruding from the back surface of the element holding member 28 is heated and heat-welded to fix the element holding member 28 to the spacer portion 26.

Further, the mounting portion 25 of the free-form surface prism 25
The positioning pin 27b protruding from the
The housing 24 and the free-form curved surface prism 25 are positioned by assembling into the fitting hole portion 24e formed in the mounting surface 24a. After that, the positioning pin 27b protruding from the back surface of the housing 24 is heated and heat-welded to the housing 24.
The free-form surface prism 25 is fixed to.

As described above, in this embodiment, the positioning bins 26a and 27b are heated so that the respective components are heat-welded, so that the assembly is facilitated and the work efficiency can be realized. In this case, since the positioning pins 26a, 27b are formed at positions sufficiently separated from the optically acting surface, the positioning pins 26a, 27b are
Heating 27b does not affect the optical performance.

21 to 23 show a thirteenth embodiment of the present invention. Here, FIG. 21 is a schematic exploded perspective view of an optical system centering on a free-form curved prism, FIG. 22 is a cross-sectional view of the free-form curved prism, and FIG. 23 is a cross-sectional view of a state in which an element holding member is attached to the free-form curved prism. .

In this embodiment, the free-form surface prism 25 is used.
The inner wall 26b of the spacer portion 26 integrally formed with
It is formed along a preset optical axis that connects the image display element 22 and the first optical surface 21a, and the inner size of the inner wall 26b is outside the element holding member 28 that holds the image display element 22. The size is formed so that it fits slidably,
By moving the element holding member 28 forward and backward along the inner wall 26b, the diopter can be adjusted.

That is, a support hole 26c is formed in one side (the side surface 25d side in the figure) of the spacer portion 26, and the shaft portion 30a of the dial type knob 30 is fitted into the support hole 26c. The dial type knob 30 is rotatably supported on the side surface of the spacer portion 26 by screwing the screw 31 inserted into the spacer portion 26 into the spacer portion 26 from the outside.

Also, the shaft portion 3 of the dial type knob 30.
0a is provided with a pin 30b protruding at a predetermined distance, and the spacer portion 26 is provided with an arc-shaped guide hole 26d that allows the pin 30b to swing.
On the other hand, on the side surface of the element holding member 28, a groove 28b into which the pin 30b is engaged is formed horizontally long. Further, a click mechanism 33 is interposed between the inner surface of the dial knob 30 and the side surface of the spacer portion 26 facing the inner surface. The click mechanism 33 includes a compression spring 33a mounted in a recess 26e formed in the spacer portion 26 and a click ball 33b supported by the compression spring 33a. The click ball 33b is provided on the inner surface of the dial type knob 30. A plurality of click grooves 33c that can be engaged with are radially formed.

In such a structure, when the dial type knob 30 rotatably attached to one side of the spacer portion 26 is rotated, the pin 30b protruding from the dial type knob 30 swings. Since the tip of the pin 30b is engaged with a groove 28b formed in a laterally long shape on the side surface of the element holding member 28, when the dial knob 30 is rotated, the pin 30b moves the groove 28b in the swinging direction. Press.

As a result, the element holding member 28 moves along the inner wall 26b of the spacer portion 26, and the image display element 22
The relative position between the first optical surface 21a and the first optical surface 21a is changed, and diopter adjustment is performed.

Also, the dial type knob 30 and the spacer portion 2
Since the click mechanism 33 is interposed between the side surface of 6 and the dial 6, there is a feeling of moderation when the dial type knob 30 is rotated. In addition, the click mechanism 33 rotates the dial type knob 30. The position after movement is retained.

As described above, in the present embodiment, since the image display element 22 can be moved along the optical axis, the diopter adjustment can be performed after the assembly, which is convenient. In addition, using the click mechanism 33, the dial type knob 3
Since the rotation angle of 0 is positioned stepwise,
Operability is good.

In this case, for example, a protrusion is formed on one of the inner wall 26b of the spacer 26 and the outer wall of the element holding member 28, and a guide groove is slidably engaged with the protrusion on the other. Alternatively, the element holding member 28 may be moved forward and backward along the optical axis direction by spline engagement between the ridge and the guide groove. Inner wall 26b of the spacer portion 26
And the outer wall of the element holding member 28 are spline-engaged with each other, so that the entire outer wall of the element holding member 28 is covered with the spacer portion 26.
Since it is not necessary to make sliding contact with the inner wall 26b, the molding is facilitated and the sliding resistance is reduced.

At this time, only one ridge portion is provided on one side, and the other surface on which the ridge portion slides and fits is not particularly grooved.
The same effect can be obtained even if only the surface accuracy is ensured. Further, on the outer wall surface of the spacer portion 26, the element holding member 2
By slidingly contacting the inner surface of the element 8, the element holding member 28
May be moved back and forth along the optical axis.

FIG. 24 shows a perspective view of a free-form surface prism according to the fourteenth embodiment of the present invention. In the present embodiment, a pair of parallel spacers 26 formed integrally with the free-form surface prism 25, which are parallel to each other and extend upward in the figure at a predetermined interval, are provided on the surface located on the second optical surface 21b side. The mounting portion 34 is integrally formed, and the mounting portion 34 extends in a direction orthogonal to the optical axis emitted from the second optical surface 21b. Reference numeral 34a is a mounting screw hole.

In this case, as shown in FIG. 25, a pair of mounting portions 34, which are parallel to each other, are provided on the image display element 22 and the first mounting portion 34.
You may make it extend in the direction along the optical axis which connects with the optical surface 21a.

FIG. 26 is a perspective view of the free-form surface prism according to the fifteenth embodiment of the present invention. In the present embodiment, the mounting portion 34 is formed on the bottom surface of the flange portion 25b that forms the bottom portion of the spacer portion 26 and extends from the first optical surface 21a to the reflective optical surface 21c side.

In this case, the mounting portion 34 is replaced by the spacer portion 2
It may be formed on the bottom surface of the flange portion 25a that constitutes the bottom portion of the No. 6 and extends in the direction from the first optical surface 21a to the second optical surface 21b. In addition, this mounting portion 34
By forming it in parallel with the optical axis emitted from the optical surface 21b, the position adjustment at the time of mounting becomes easy.

FIG. 27 is a perspective view of the free-form surface prism according to the sixteenth embodiment of the present invention. 15th mentioned above
In the embodiment, from the first optical surface 21a to the reflective optical surface 2
Although the mounting portion 34 is provided on the bottom surface of the flange portion 25b extending to the 1c side, in the present embodiment, the first optical surface 21a to the both side surfaces 21d constituting the bottom portion of the spacer portion 26 are provided.
The mounting portion 34 is formed on the bottom surface of the flange portion extending in the direction.

In this case, the mounting portion 34 is attached to the second optical surface 2
By forming it in parallel with the optical axis emitted from 1b, the position adjustment at the time of mounting becomes easy.

FIG. 28 is a perspective view of the free-form surface prism according to the seventeenth embodiment of the present invention. The present embodiment is a modification of the above-described sixth embodiment (see FIG. 9). That is, in the sixth embodiment, the pair of mounting portions 23 that are parallel to each other extend from both ridges on the reflecting optical surface 21c side in the invalid light flux range of the first optical surface 21a, but in the present embodiment, In the invalid light flux range of the reflection optical surface 21c, the projections are extended from both ridges on the first optical surface 21a side to the upper side of the drawing, and the same effect as that of the sixth embodiment can be obtained.

FIG. 29 is a perspective view of a free-form surface prism according to the eighteenth embodiment of the present invention. The present embodiment is a modification of the above-described third embodiment (see FIG. 6).

That is, in the third embodiment, a pair of mounting portions 23 parallel to each other are provided on the upper surface of the first optical surface 21a.
Although the bridge is formed in a bridge girder shape, in the present embodiment, the mounting portion 3
6 is made to project from the edge of the reflection optical surface 21c on the first optical surface 21a side in parallel with the optical axis emitted from the second optical surface 21b. The insertion holes 36a are formed at regular intervals.

Then, the upper surface or the bottom surface of the mounting portion 36 is brought into contact with a mounting surface (not shown) of the housing, and the screw inserted into the screw insertion hole 36a is screwed into the housing to form a free-form surface. The prism 21 is fixed to the housing.

In this case, as shown in FIG. 30, the mounting portion 36 may be projected in the direction of the second optical surface 21b.

As described above, according to this embodiment, the mounting portion 36 is projected from the first optical surface 21a toward the reflective optical surface 21c or the second optical surface 21b, and the side surface 21d is formed.
The free curved surface prism 21
The space between the housing and the housing on which the free-form surface prism 21 is fixed can be effectively used.

The present embodiment has been described based on the case where it is applied to the free-form surface prism shown in FIG. 1, but it can be similarly applied to the free-form surface prism as shown in FIG.

[0114]

As described above, according to the present invention,
Since the element fixing attachment part is not projected from the side surface that does not contribute to the optical action of the optical element, the structure is simplified and the space can be effectively used, and the overall size of the device can be reduced. it can.

Further, since the optical element can be fixed to the housing without causing any harmful optical distortion, no internal stress is generated in the optical element and the optical characteristics can be guaranteed for a long time.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image observation apparatus.

[Fig. 2] Configuration diagram of free-form surface prism

FIG. 3 is a schematic configuration diagram of an image observation apparatus according to another aspect.

FIG. 4 is a perspective view of a free-form surface prism according to the first embodiment.

FIG. 5 is a perspective view of a free-form surface prism according to a second embodiment.

FIG. 6 is a perspective view of a free-form surface prism according to a third embodiment.

FIG. 7 is a perspective view of a free-form surface prism according to a fourth embodiment.

FIG. 8 is a perspective view of a free-form surface prism according to a fifth embodiment.

FIG. 9 is a perspective view of a free-form surface prism according to a sixth embodiment.

FIG. 10 is a perspective view of a free-form surface prism according to a seventh embodiment.

FIG. 11 is a partial cross-sectional front view of the same in which the free-form surface prism is fixed to the housing.

FIG. 12 is a perspective view of a free-form surface prism according to an eighth embodiment.

FIG. 13 is a partially sectional front view of the same in which the free-form surface prism is fixed to the housing.

FIG. 14 is a perspective view of a free-form surface prism according to a ninth embodiment.

FIG. 15 is a partial cross-sectional front view of the same in which the free-form curved prism is fixed to the housing.

FIG. 16 is a perspective view of a free-form curved surface prism according to a tenth embodiment.

FIG. 17 is a perspective view of a free-form surface prism according to an eleventh embodiment.

FIG. 18 is a perspective view of a free-form surface prism according to the modification of FIG.

FIG. 19 is a perspective view of a free-form surface prism according to a twelfth embodiment.

FIG. 20 is a sectional view of the free-form curved prism of the same.

FIG. 21 is a schematic exploded perspective view of an optical system centering on a free-form surface prism according to a thirteenth embodiment.

FIG. 22 is a sectional view of the free-form curved prism of the same.

FIG. 23 is a sectional view showing a state where an element holding member is attached to the free-form surface prism.

FIG. 24 is a perspective view of a free-form surface prism according to a fourteenth embodiment.

FIG. 25 is a perspective view of a free-form surface prism according to a modification of FIG.

FIG. 26 is a perspective view of a free-form surface prism according to a fifteenth embodiment.

FIG. 27 is a perspective view of a free-form surface prism according to a sixteenth embodiment.

FIG. 28 is a perspective view of a free-form surface prism according to a seventeenth embodiment.

FIG. 29 is a perspective view of a free-form surface prism according to the eighteenth embodiment.

FIG. 30 is a perspective view of a free-form surface prism according to a modification of FIG.

FIG. 31 is an exploded perspective view of essential parts of a conventional image observation apparatus.

FIG. 32 is an exploded perspective view of a main part of an image observation apparatus according to another conventional mode.

FIG. 33 is a right side view, partly in section, of FIG. 32 in the same assembled state.

FIG. 34 is a perspective view of a main part of an image observation apparatus according to another conventional mode.

FIG. 35 is an exploded perspective view of the main part of the image observation apparatus of the same.

FIG. 36 is a right side view, partly in section of FIG.

FIG. 37 is a perspective view of a main part of an image observation apparatus according to still another aspect of the related art.

FIG. 38 is a perspective view of a conventional free-form surface prism.

[Explanation of symbols]

21,21'25 Free-form surface prism (optical element) 21a First optical surface 21b Second optical surface 21c, 21c 'reflective optical surface 21d side 21e, 21f Slit (groove) 21g, 21h counterbore 21j Slit (groove) 22 Image display device 23, 25c, 27, 34, 36 Element fixing attachment part 26 Spacer 26b Inner wall (guide part) 28 element holding member

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02B 25/00 H04N 5/64 511A H04N 5/64 511 G02B 7/18 A F term (reference) 2H043 AE07 AE22 BA01 2H087 KA14 KA23 RA06 RA41 TA01 TA04 TA05 TA06

Claims (7)

[Claims] 1. An optical element for enlarging an image displayed on a small image display element, comprising: a first optical surface that substantially opposes a display surface of the image display element to capture an image; A second optical surface that reflects an incident light ray inside the element and finally emits a magnified image light ray to an eyeball of an observer, and an incident light from the first optical surface is incident on the second optical surface. Any one of the first to second optical surfaces and the reflective optical surface having at least one reflective optical surface that contributes to internal reflection at least once and a side surface that does not contribute to an optical action. An optical element characterized in that a mounting portion for fixing the element is provided on the. 2. An optical element for enlarging an image displayed on a small image display element, comprising: a first optical surface which substantially opposes a display surface of the image display element to capture an image; A second optical surface that reflects an incident light ray inside the element and finally emits a magnified image light ray to an eyeball of an observer, and an incident light from the first optical surface is incident on the second optical surface. It has at least one reflection optical surface that contributes to internal reflection at least once, and a side surface that does not contribute to optical action, and further comprises an element fixing attachment part, wherein the element fixing attachment part is an element. An optical element characterized by being formed separately from the element by a groove formed in any two or more of the surfaces forming the element. 3. The at least one of the first and second optical surfaces and the reflective optical surface has a shape that is plane-symmetric with respect to only one target surface. The optical element described. 4. The element fixing attachment portion is provided on a spacer portion formed in a cylindrical shape from the first optical surface toward the image display element.
3. The optical element according to any one of 3 above. 5. At least a part of the spacer portion forms a guide portion in a direction substantially parallel to an optical axis incident on the first optical surface, and an element holding member that holds the image display element is the guide. The optical element according to claim 4, wherein the optical element is configured to be movable along the portion. 6. The element fixing mounting portion is formed on a surface parallel or orthogonal to an optical axis incident on the first optical surface. Optical element. 7. The element fixing mounting portion is formed on a surface parallel or orthogonal to an optical axis emitted from the second optical surface. Optical element.