JPH04179909A - Optical system for lens barrel - Google Patents

Abstract

PURPOSE:To prevent the posture of an image from being changed by positioning an incident optical axis on a 1st optical element, an outgoing optical axis from a 3rd optical element and 1st and 2nd reflected optical axes, on the same plane. CONSTITUTION:This system is provided with the 1st optical element 6 which bends the course of a light beam having the incident optical axis AI, which passes through an objective lens 5 and is made incident, at right angle, a 2nd optical element 7 which bends the course of the incident light beam from the 1st optical element 6 at right angle twice and projects the light beam in a parallel and opposite direction to the incident light beam at a position where the optical axis is misaligned, and the 3rd optical element 8 which bends the incident light beam from the element 7 at right angle to project as the light beam having the outgoing optical axis A0. When the incident optical axis AI and the outgoing optical axis A0 are parallel and in the same direction, the incident optical axis AI, the outgoing optical axis A0 and the 1st reflected optical axis A1 and the 2nd reflected optical axis A2 are made to position on the same plane. Thus, the nearly same height of an eye point is obtained at the same angle of depression or at a smaller angle, and the posture of the image is not changed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical system for a lens barrel in a microscope or the like, in which the inclination angle of the lens barrel can be changed.

[Conventional technology]

2. Description of the Related Art Conventionally, there is a microscope that is capable of changing the inclination angle of a lens barrel, that is, the inclination angle of an eyepiece optical axis, as described in, for example, Japanese Unexamined Patent Publication No. 195602/1983. This microscope has two rotational axes for three optical elements that coincide with the reflection optical axis between the two optical elements, and by linking the rotational movements of multiple optical elements, an erected image can be created. This allows the tilt angle of the lens barrel to be changed without changing the posture.

Furthermore, an optical system for a lens barrel of a microscope having the same basic configuration as this microscope is described in Japanese Patent Application Laid-Open No. 60-91322. This optical system is shown in Figure 6 (al, (b)).
In the figure, the triangular prism 1 has an incident optical axis a1 that enters from below through an imaging lens (not shown).
The trapezoidal prism 2 is bent at a right angle and set as the first reflection optical axis al.
make it incident on the In the trapezoidal prism 2, the first reflected optical axis al
is bent at a right angle in a prism to form a second reflection optical axis a2, and further bent at a right angle to form a third reflection optical axis a3 parallel to and in the opposite direction to the first reflection optical axis al. (second triangular prism) 3. In the binocular eyepiece unit 3, the luminous flux of the third reflected optical axis al is split into two parts, bent at a right angle, and guided to the respective eyepieces as an output optical axis a0.

Further, the first and third reflection optical axes a1+83 are each formed by a trapezoidal prism 2. It constitutes the rotation axis of the binocular eyepiece unit 3, and gears having the same effective diameter are fixed to the triangular prism l and the binocular eyepiece unit 3, respectively, and are meshed with each other. Therefore, when the trapezoidal prism 2 is rotated by a certain angle with respect to the triangular prism l, the binocular eyepiece unit 3 is rotated by an equal angle in the same direction with respect to the trapezoidal prism 2. Then, an incident optical axis a, and an exit optical axis a. are parallel and in the same direction, and the first to third reflection optical axes a1. H
a 2 + a 3 is the incident optical axis al and the exit optical axis a0
(see FIG. 6 (al)).

Therefore, under the above-mentioned configuration, when trying to change the inclination angle of this lens barrel optical system from the position where the exit optical axis a is horizontal as shown in FIG. 6 (bl solid line), for example, When the trapezoidal prism 2 is rotated by an angle α around the first reflection optical axis al, the binocular eyepiece unit is also rotated by an equal angle with respect to the trapezoidal prism 2 around the third reflection optical axis al, resulting in an angle of 2α.
The angle of inclination will change.

[Problem to be solved by the invention]

By the way, in the above-mentioned lens barrel optical system, by shortening the optical path length, there is no need for extension using a lens relay system even when the distance from the imaging lens or objective lens to the image is short. Since the eyepiece eyepoint and the rotation axis for changing the tilt angle, that is, the reflection optical axis al+a3 are close to each other, considering that another effect of changing the optical axis tilt angle is the elevation of the eyepoint. There is a problem in that the lifting stroke becomes small and a sufficient stroke cannot be obtained.

In addition, the above-mentioned lens barrel optical system is inconvenient because the height of the eye point relative to the position is considerably lower when installed on the microscope body, compared to a fixed tilt angle lens barrel that has a declination prism and a binocular eyepiece unit. be.

In other words, when changing the lens barrel of a microscope from a fixed tilt angle lens barrel to the variable tilt angle lens barrel described above, the depression angle must be considerably increased in order to obtain the same eye point height as the fixed tilt angle lens barrel. It gets bigger. Furthermore, even if a microscope with a fixed tilt angle barrel and a microscope with a variable tilt angle barrel like the one described above are placed side by side on the same desk, the examination posture will change considerably if they are used alternately. . Generally, when the angle of depression increases to an extent exceeding 45°, the observer is forced to turn his or her head downward, making it difficult to use the device.

Furthermore, regarding the posture (vertical relationship) of the observed image, a fixed tilt angle lens barrel results in an inverted image, whereas the above-mentioned variable tilt angle lens barrel results in an erect image, which reverses the scanning operation of the specimen. However, it has the disadvantage that it is inconvenient when attaching or changing the lens barrel.

In view of these problems, the present invention makes it possible to obtain the same eyepoint height with the same or smaller depression angle when used as a replacement for a normal fixed tilt angle lens barrel. Another object of the present invention is to provide an optical system for a lens barrel whose tilt angle is variable so that the attitude of the image does not change.

[Means to solve the problem]

The optical system for a lens barrel according to the present invention includes a first optical element that reflects an incident angle at a right angle to form a first reflected optical axis, and a first optical element that bends the first reflected optical axis twice at right angles to produce a first reflected light. a second optical element having a second reflective optical axis parallel to and in the opposite direction to the axis and rotatable about the first reflective optical axis; and a second optical element that reflects the second reflective optical axis at right angles to serve as an exit optical axis. and a third optical element rotatable around the second reflective optical axis; a first bidirectional member rotatable around the first reflective optical axis and fixed to the first optical element; a second gear member that is rotatable about the second reflective optical axis, is fixed to the third optical element, meshes with the first and both members, and has the same diameter as the first and both members; When the incident optical axis and the exit optical axis are parallel and in the same direction,
It is characterized in that the incident optical axis, the exit optical axis, the first reflected optical axis, and the second reflected optical axis are located on the same plane.

[For production]

When changing the inclination angle, when the second optical element is rotated by an angle α relative to the first optical element, the second gear member rotates at the same angle while revolving at an angle α relative to the first and both gear members, so that the third The optical element rotates by an angle α in the same direction with respect to the second optical element, resulting in a change in the angle of inclination 2α, and the lifting stroke of the eyepoint at this time is relatively large. Also, even when used as a replacement for a regular fixed tilt angle lens barrel, the eyepoint height can be maintained at the same level with the same or smaller depression angle than the fixed tilt angle lens barrel. At the same time, the posture of the statue does not change.

〔Example〕

Hereinafter, the present invention will be described in detail according to illustrated embodiments.

First, in FIG. 1, 5 is an objective lens (or imaging lens) of a microscope (not shown), and 6 is a first optical element that bends the course of the light beam having the incident optical axis a1 that has passed through the objective lens 5 at a right angle. as a prism, 7 is the first optical element 6
as a second optical element which is placed on the side of the first optical element 6 and bends the path of the incident light ray from the first optical element 6 at right angles twice to emit the light beam parallel to and in the opposite direction to the incident light ray at a position where the optical axis is shifted. In the prism, A is a reflection optical axis that is the center of rotation of the second optical element 7 with respect to the first optical element 6, and A2 is a reflection optical axis formed by bending the reflection optical axis A1 at a right angle in the second optical element 7. , 8 are disposed facing a part of the second optical element 7 and bend the incident light beam from the second optical element 7 at right angles to form an exit optical axis A. The third optical element A3, which emits a light beam having , is a reflection optical axis that is the center of rotation of the third optical element 8 with respect to the second optical element 7.

Reference numeral 9 indicates an optical axis A of light emitted from the third optical element 8. A beam splitting prism divides the incident light into a left-eye visual system light beam and a right-eye visual system light beam, 10 is a prism that bends the left-eye visual system light beam at right angles and guides the light beam to an eyepiece (not shown), and 11 is a right-eye optical system beam splitting prism. These prisms bend the visual system light beam at right angles and guide the light beams to the eyepiece lenses (not shown), and these prisms constitute the binocular eyepiece section 12 and rotate together with the third optical element 8 .

Basically, when the second optical element 7 is rotated about the reflection optical axis A1, the third optical element 8 is also rotated together.

Moreover, in the present invention, the first to third optical elements 6°7.8 are mounted so as to satisfy the conditions i) and ii) shown below.

i) When the second optical element 7 is rotated by a certain angle with respect to the first optical element 6, the third optical element 8 is rotated by an equal angle in the same direction with respect to the second optical element 7.

Alternatively, the first optical element 6 and the third optical element 8 are rotated at equal angles in opposite directions with respect to the second optical element 7.

ii) When the incident optical axis A+ to the first optical element 6 and the output optical axis Ao from the third optical element 8 are parallel and in the same direction, these optical axes A+, Ao and the reflected optical axis AH, the reflected light The axis A2 and the reflection optical axis A are located on the same plane.

Regarding the above condition i), in FIG. 1, the reflective surface of the first optical element 6 and one reflective surface of the second optical element 7 are in opposing positions, and Since the surface and the reflective surface of the third optical element 8 are in opposing positions,
Even if the attitude of the image changes by rotating the second optical element 7 by a certain angle, the rotation of the image can be suppressed by rotating the third optical element 8 by the same angle with respect to the second optical element 7. . Therefore, the inclination angle of the binocular eyepiece 12, that is, the lens barrel, can be changed without changing the posture of the image.

FIG. 2 shows its specific configuration.

Figure (a) is a plan view of each optical element 6 to 8, and figure (b) is a figure (
It is an explanatory diagram showing the connection of gears seen from the front direction with respect to a), 14 is a first gear concentric with the reflection optical axis A1 and fixedly arranged on the first optical element 6, and I5 is the reflection optical axis. A
, and is fixedly disposed on the third optical element 8, meshes with the first gear 14, and has the same effective diameter as the first gear 14.

This embodiment is constructed as described above, and its operation will be explained based on FIGS. 2 and 3. Furthermore, Figure 3 (al
In Figure (a), the second optical element 7 is represented by a three-dot chain line, and in Figure (a), FC+, the first and second gears 14, 15
is omitted.

In FIG. 3(a), the optical system for a lens barrel according to this embodiment, indicated by a two-dot chain line, has optical axes A, AO, A, A2, . A3 is in the position, and the eye point is at the highest position. In order to change the inclination angle from this state, the second optical element 7 is set to reflect the optical axis A with respect to the first optical element 6.

When rotated by an angle α around , the second gear 1 shown in FIG.
5 rotates at the same angle while revolving at an angle α with respect to the first gear 14, the third optical element 8 (and binocular eyepiece unit 12)
is inclined at an angle α with respect to the second optical element 7 fa)
The position shown by the solid line is reached. In this state, the third optical element 8 is in a position inclined at an angle of 2α with respect to the first optical element 6.

At this time, if α=45°, the inclination angle of the lens barrel, that is, the exit optical axis A. is in a horizontal position. On the other hand, if the optical system of a normal fixed-angle lens barrel is shown in FIG. It will pass through section 12 with the same angle of depression. Comparing the eye point with a horizontal tilt angle in this example (see Figure 3 (al)) and the eye point with a fixed tilt angle lens barrel (see Figure 3 (b)), it is found that the height is approximately the same. Therefore, when observing by replacing the lens barrel according to this embodiment with the fixed tilt angle lens barrel, or alternately observing each microscope to which these lens barrels are attached, the eye point will be approximately the same. Moreover, the lens barrel according to this embodiment has a smaller angle of depression.

Then, as shown in FIG. 3(C), when the second optical element 7 is rotated upward at an angle β from the horizontal position, the third optical element 8 and the binocular eyepiece 12 are moved in the same direction at an angle 2β. It will rotate. In this case, because the reflection optical axis A is structurally always located above the reflection optical axis A (see drawing),
The lifting stroke of the eyepoint when changing the inclination angle becomes considerably larger compared to the above-mentioned prior art.

In this embodiment, the image is rotated by tilting the second optical element 7 at an angle α or β with respect to the first optical element 6, but the third optical element 8 that receives this reflected light also tilts at an angle α or β in the same direction. Although it is tilted by β, the attitude of the image reflected by the third optical element 8 does not change. Therefore, in the binocular eyepiece section 12, the image of the objective lens 5 is maintained in an inverted position regardless of the change in the inclination angle. Therefore, an image in the same direction as the fixed tilt angle lens barrel can be obtained.

If the angle α exceeds 45@ in FIG. 3 (a) J, the rotation angle of the third optical element 8 with respect to the first optical element 6 will exceed 90 degrees, and the angle of depression will become negative, so the speculum posture will change. becomes significantly worse. Therefore, it is preferable that the angle α≦45°.

As described above, according to this embodiment, it is possible to increase the vertical stroke of the eyepoint when changing the inclination angle of the lens barrel. In addition, when the variable tilt angle lens barrel according to this embodiment is used interchangeably with the fixed tilt angle lens barrel, or when two microscopes each equipped with both lens barrels are placed side by side and observed alternately,
In order to obtain the same eyepoint height, this example requires a smaller depression angle than a fixed tilt angle lens barrel, so the examination posture does not change much and the degree to which the head is turned downward is small, making observation easier. . Moreover, since the posture of the image does not change, observation is easy in this respect as well, and the scanning operation of the specimen is convenient because it does not reverse.

Regarding the optical system of this embodiment, if the distance to the image of the objective lens 5 is 160 + o + n or more and the number of fields of view is about 23 or less, it can be configured only with prisms without extending the image with a relay lens. .

Next, FIG. 4 shows a first modification of the present invention,
A polarizing prism 17 is disposed on the incident side of the first optical element 6 to reflect the light beam so that the incident optical axis A1 has a predetermined angle. Therefore, in the case of this embodiment, each optical axis A + 1 A o + A1 . that satisfies condition ii). The plane containing A2 and As will also be configured at a predetermined angle. or,
A beam splitting prism 9 of the binocular eyepiece 12 is arranged as the third optical element 8.

FIG. 5 shows a second modification of the present invention, in which the optical path length becomes longer by arranging the deflection prism 17 in front of the first optical element 6, so a lens relay system is arranged to change the image. It is stretched.

That is, FIG. 5(a) shows an optical system in which the relay lens is omitted, and FIG. 5(b) shows the optical system in which the first to third optical elements 6.
FIG. 7.8 is a plan view showing the relay lens group. In the figure, 18 is a convex lens placed between the first and second optical elements 6°7, 19 is a concave-convex lens placed between the second and third optical elements 7 and 8, and 20 is a concave-convex lens between the concave-convex lens 19 and the third optical element. This is a convex lens placed between the optical elements 8.

According to this configuration, since the concave-convex lens 19 and the like are arranged in front of the inverted image, the image is enlarged and the image formation position can be moved away. Therefore, even if the optical path length becomes long, the image can be stretched without forming an intermediate image (the image can be stretched as an inverted image).

Incidentally, the binocular eyepiece section 12 may be of either a zigzag type or a jeep-tooth type.

Further, although the above-described embodiment relates to a binocular section, it goes without saying that it can also be applied to a single observation lens barrel. Further, mirrors may be used instead of prisms as the first to third optical elements 6, 7.8. Furthermore, the arrangement of the relay lenses is not limited to the above-mentioned embodiments, and can be modified in various ways.

In addition, the first gear 14. The second gear 15 is a first tooth member,
It constitutes the second tooth force member.

〔Effect of the invention〕

As described above, in the optical system for a lens barrel according to the present invention, the optical axis of incidence on the first optical element, the optical axis of exit from the third optical element, and the first and second reflective optical axes are located on the same plane. Since the eye point is configured to be able to change the tilt angle, it is possible to increase the vertical stroke of the eye point when changing the inclination angle. In addition, compared to a normal fixed tilt angle lens barrel, it is possible to obtain the same eye point height with the same or smaller depression angle, and the image attitude does not change, which is an important practical advantage.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of each optical element in an embodiment of the optical system for a lens barrel according to the present invention, and Figure 2 (al is the configuration of each optical element, (b) is a diagram of each gear corresponding to figure fa). Figures showing the positional relationships, Figure 3 (al is a diagram of the optical system showing changes in the tilt angle for the example, (b) is a diagram showing the optical system of a fixed tilt angle lens barrel, (C) is a diagram for the example FIG. 4 is a diagram showing the positional relationship of each optical element for the first modification of the present invention, and FIG. 5(a) is for the second modification of the present invention. Figure 4 is similar to Figure 4, (b) is a diagram showing the main optical system, and Figure 6 is a diagram showing the conventional technology, where (a) is the optical system and (b) is a diagram with a different tilt angle. It is a diagram showing the positional relationship of each optical element at the time. 6...first optical element, 7... second optical element, 8
...Third optical element, 14...First gear, I5.
...Second gear. (a) Figure 4 Figure 5 (a) Procedural amendment (voluntary) July 9, 1991 1, Case description Patent Application No. 2-308191 2, Name of invention Optical system for lens barrel 4 , representative
People Address: 19, Shinbashi 5, Minato-ku, Tokyo 105 Phone: Tokyo (
3432) 4576 5. Detailed description of the invention and scope of claims in the specification subject to amendment. 6. Contents of the amendment (11 Claims are corrected as attached. (2) "Rotating" in the second line of page 7 of the specification is deleted. (3) 9 of page 11 of the specification "Second optical element 7" in row
Insert the optical axis AtJ after "." (4) From page 15, line 19 of the specification to page 16, line 3, [
You can stand in front of an inverted statue. '' is corrected to ``Because it forms an intermediate image, it becomes an erect image. a second optical element whose reflective optical axis is bent twice at right angles to form a second reflective optical axis parallel to and opposite to the first reflective optical axis, and which is rotatable about the first reflective optical axis; a third optical element that reflects a second reflected optical axis at right angles to serve as an output optical axis and is rotatable about the second reflected optical axis; and a first optical element that is rotatable about the first reflected optical axis. a first gear member that is fixed to the second gear member; and a first gear member that is rotatable about the second reflective optical axis and is fixed to the third optical element, that meshes with the first gear member and is the same as the first gear member. a second gear member having a diameter, and when the input optical axis and the output optical axis are parallel and in the same direction, the input optical axis, the output optical axis, the first reflected optical axis and the second An optical system for a lens barrel in which two reflective optical axes are located on the same plane.

Claims (1)

[Claims] A first optical element that reflects an incident optical axis at right angles to form a first reflected optical axis; and a first optical element that bends the first reflected optical axis twice at right angles to form the first reflected optical axis. a second optical element having a parallel and oppositely directed second reflective optical axis and rotatable about the first reflective optical axis; a third optical element rotatable about the second reflective optical axis; a first gear member rotatable about the first reflective optical axis and fixed to the first optical element; a second gear member that is rotatable about the second reflective optical axis, is fixed to the third optical element, meshes with the first gear member, and has the same diameter as the first gear member; When the input optical axis and the output optical axis are parallel and in the same direction, the input optical axis, the output optical axis, the first reflected optical axis, and the second reflected optical axis are positioned on the same plane. Optical system for the lens barrel.