JP2017211410A - Optical unit and optical instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical unit in which bond strength is not decreased and an optical element is less deformed.SOLUTION: An optical unit 10A comprises: a lens 11; a frame 12A through which the lens 11 is inserted; a fitting part 12a which is arranged on an inner peripheral part of the frame 12A, and fitting with the lens 11 opposite a side face of a lens side face 11c; an adhesive storage part 12b which is arranged adjacent to the fitting part 12a in a direction along a central axial line of the lens side face 11c in the inner peripheral part of the frame 12A, and has a wider first gap radially from the lens side face 11c than a second gap radially between the lens side face 11c and the fitting part 12a; and an adhesive setting body 13 fastened on the surface of the adhesive storage part 12b and the lens side face 11c and coupling and fixing the adhesive storage part 12b and the lens side face 11c. The length of the fitting part 12a along the central axial line is shorter than the adhesion length along the central axial line of the adhesive setting body 13 in contact with the lens side face 11c.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an optical unit and an optical apparatus.

In an optical apparatus, an optical unit in which an optical element such as a lens is fixed to a frame is used. As a method for fixing the optical element and the frame, for example, it is known to use an adhesive such as a UV curable adhesive.
For example, in Patent Document 1, a chamfered portion that is opposed to the edge surface of the lens over 0.5 mm or more is formed at the tip of the holding member (frame), and the photocurable adhesive is between the chamfered portion and the edge surface of the lens. The holding structure of the optical component in which the lens is bonded is described.
For example, in Patent Document 2, a chamfered portion is formed at the tip of a lens barrel (frame), and a foam layer is formed between the side surface of the lens to be held and the inner peripheral surface including the chamfered portion of the lens barrel. It is described that the held lens is held.

JP 2001-33677 A JP-A-8-43700

However, the conventional optical unit as described above has the following problems.
According to the technique described in Patent Document 1, since the light-curing adhesive mixed with a light-shielding substance serves to shield the edge surface of the lens and adhere to the holding member, the adhesive is used for the lens. It is applied and cured over the entire edge surface.
Since the adhesive causes curing shrinkage at the time of curing, stress due to shrinkage of the cured body of the adhesive acts on the edge surface of the lens after the adhesive is cured. Since the stress at the edge surface of the lens causes internal distortion in the lens, the lens surface is distorted.
As a result, since the surface accuracy of the lens is deteriorated, there is a problem that the optical performance is likely to deteriorate.
Although it is conceivable to suppress distortion of the lens surface by reducing the amount of adhesive applied, if the amount of adhesive applied decreases too much, the adhesive strength decreases and impact resistance decreases. There is a problem.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical unit and an optical apparatus that can reduce distortion of an optical element without reducing adhesive strength.

  In order to solve the above problems, an optical unit according to a first aspect of the present invention is disposed on an optical element, a frame in which the optical element is inserted, and an inner periphery of the frame, and the optical element A fitting portion that is fitted to the optical element so as to face the side surface of the optical element, and is arranged adjacent to the fitting portion in a direction along a central axis of the side surface of the optical element, in an inner peripheral portion of the frame. And a first space between the side surface in the radial direction is wider than a second space between the side surface in the radial direction and the fitting portion, a surface of the adhesive housing portion, and the surface An adhesive cured body fixed to the side surface of the optical element and connecting and fixing the surface of the adhesive container and the side surface of the optical element; and the side surface of the optical element And the length along the central axis of the portion where the fitting portion faces in the radial direction But in the adhesive cured material, shorter than the length along the center axis of the attachment site where the are fixed to the portion of the side surface of the optical element facing the radial direction and the adhesive receiving portion.

  In the optical unit, the adhesive accommodating portion may include a tapered surface having an inclination angle with respect to the central axis of the fitting portion greater than 45 ° and 60 ° or less at a portion adjacent to the fitting portion. .

  In the optical unit, the adhesive container may include a curved surface having a curved cross section including the central axis at a portion adjacent to the fitting portion.

  In the optical unit, the fitting portion, the adhesive accommodating portion, and the adhesive cured body may each be formed along the entire circumference in the circumferential direction of the side surface of the optical element.

  In the optical unit, the inner peripheral portion of the frame is adjacent to the fitting portion in the axial direction, is positioned on the opposite side of the adhesive accommodating portion, and is third from the side surface of the optical element in the radial direction. An enlarged-diameter portion having a larger interval than the second interval may be formed.

  The optical apparatus of the 2nd aspect of this invention is equipped with the said optical unit.

  According to the optical unit and the optical apparatus of the present invention, there is an effect that the distortion of the optical element can be reduced without reducing the adhesive strength.

It is a typical front view which shows the structural example of the optical unit and optical apparatus of the 1st Embodiment of this invention. It is a typical side view showing the 1st example of composition of the optical unit of a 1st embodiment of the present invention. It is AA sectional drawing in FIG. It is an enlarged view of the B section in FIG. It is typical sectional drawing of the cross section containing the optical axis which shows the 2nd structural example of the optical unit of the 1st Embodiment of this invention. It is an enlarged view of the D section in FIG. It is typical sectional drawing of the cross section containing the optical axis which shows the principal part of the 3rd structural example of the optical unit of the 1st Embodiment of this invention. It is typical sectional drawing of the cross section containing the optical axis which shows the principal part of the 4th structural example of the optical unit of the 2nd Embodiment of this invention. It is typical sectional drawing of the cross section containing the optical axis which shows the principal part of the 5th structural example of the optical unit of the 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.

[First Embodiment]
An optical apparatus according to the first embodiment of the present invention will be described.
FIG. 1 is a schematic front view illustrating a configuration example of an optical unit and an optical apparatus according to the first embodiment of the present invention.

  As shown in FIG. 1, the microscope 1 (optical apparatus) of this embodiment includes a main body 2, a stage 3, objective lenses 5A and 5B (optical units), an eyepiece lens 7, a camera 8, and illumination devices 9A and 9B. Prepare.

  The main body 2 supports each member of the microscope 1. The main body portion 2 has a base portion 2 a disposed on the placement surface F. A column portion 2b is erected on the base portion 2a. The lens barrel support 2c extends in the horizontal direction from the upper end of the column 2b. The tip of the lens barrel support part c is opposed to the base part 2a above the base part 2a.

  The stage 3 places the test sample 4 so as to be movable in the horizontal direction and along the optical axis L of the microscope 1. The stage 3 is disposed on the base portion 2a.

The objective lenses 5A and 5B are optical units that connect images of the sample 4 to be examined. The objective lenses 5A and 5B have different magnifications. Each of the objective lenses 5A and 5B includes one or more lenses and a frame that holds the lenses. A fixing portion that is detachably fixed to a revolver 6 described later is provided at the end of each frame. As a specific example of the structure of the fixing portion, for example, a male screw can be cited.
A specific configuration centering on the lens and frame fixing structure in the objective lenses 5A and 5B will be described later.

The revolver 6 is disposed at a position facing the stage 3 on the lower surface of the lens barrel holding portion 2 c of the main body portion 2. The revolver 6 detachably holds a plurality of objective lenses. In the example shown in FIG. 1, objective lenses 5 </ b> A and 5 </ b> B are held by the revolver 6. The revolver 6 may simultaneously hold three or more objective lenses.
The revolver 6 can be rotated according to the operation of the operator. The revolver 6 positions the objective lens so that the optical axis of the objective lens attached to the revolver 6 is coaxial with the optical axis L of the microscope 1 at a plurality of rotational positions. In the example shown in FIG. 1, the objective lens 5 </ b> A is arranged coaxially with the optical axis L. In the following description, it is assumed that the objective lens 5A is used as the objective lens of the microscope 1.

The eyepiece 7 constitutes an eyepiece optical system for the user to observe the image of the objective lens 5A disposed on the optical axis L.
Although the eyepiece lens 7 has a lens configuration different from that of the objective lenses 5A and 5B, the eyepiece lens 7 may be configured by the optical unit of the present embodiment, similarly to the objective lenses 5A and 5B.

The camera 8 is a device portion that captures an image of the objective lens 5A disposed on the optical axis L. The camera 8 includes an imaging lens unit that includes a lens (not shown) and a frame that holds the lens, and an imaging element.
Although the imaging lens unit has a lens configuration different from that of the objective lenses 5A and 5B, the imaging lens unit may be configured by the optical unit of the present embodiment, similarly to the objective lenses 5A and 5B. That is, the camera 8 may be an optical device including the optical unit of the present embodiment.
An image signal of an image captured by the camera 8 is sent to an appropriate display device (not shown) and displayed on the display screen of the display device.

The illumination devices 9A and 9B are device portions that generate illumination light that illuminates the test sample.
The illumination light of the illumination device 9A is used for epi-illumination. The illumination light of the illumination device 9B is used for transmitted illumination.
Each of the lighting devices 9A and 9B includes a light source (not shown) and an illumination lens unit (not shown).
The illumination lens units of the illumination devices 9A and 9B are different in lens configuration from the objective lenses 5A and 5B, but may be configured by the optical unit of the present embodiment, similarly to the objective lenses 5A and 5B. That is, the illuminating devices 9A and 9B may be optical devices including the optical unit of the present embodiment.

Next, a configuration example of the optical unit 10 of the present embodiment will be described.
FIG. 2 is a schematic side view showing a first configuration example of the optical unit according to the first embodiment of the present invention. 3 is a cross-sectional view taken along the line AA in FIG. FIG. 4 is an enlarged view of a portion B in FIG.

In the microscope 1, at least the objective lenses 5A and 5B have the configuration of the optical unit 10 of the present embodiment. However, since the optical unit 10 according to the present embodiment is characterized by the fixing structure between the optical element such as a lens and the frame, the following description will focus on the fixing structure between the optical element alone and the frame.
When the objective lenses 5A and 5B are provided with a plurality of optical elements, it is only necessary to provide a fixing structure described below for each optical element.

  In this specification, when describing the relative position with respect to an axial member, a cylindrical member, or the like that can specify an axis such as the optical axis or the central axis, the direction along the axis is the axial direction, and the direction of circling around the axis is the circumferential direction. A direction along a line intersecting the axis in a plane orthogonal to the axis is referred to as a radial direction. In particular, the direction along the optical axis may be referred to as the optical axis direction.

A first configuration example of the optical unit 10 of the present embodiment will be described.
As shown in FIGS. 2 and 3, an optical unit 10A, which is a first configuration example of the optical unit 10, includes a lens 11 (optical element), a frame 12A in which the lens 11 is inserted, and the lens 11 fixed to the frame 12A. The cured adhesive 13 is provided.

As shown in FIG. 3, the lens 11 has a first lens surface 11a and a second lens surface 11b. A lens side surface 11c (side surface of the optical element) which is a cylindrical surface is formed on the outer peripheral portion between the first lens surface 11a and the second lens surface 11b. A center axis line (not shown) of the lens side surface 11c and the lens optical axis O of the lens 11 are coaxial.
In this configuration example, the lens 11 is a biconvex lens. For this reason, both the first lens surface 11a and the second lens surface 11b are convex surfaces.
The surface shapes of the first lens surface 11a and the second lens surface 11b are not particularly limited, and for example, a spherical surface, an aspheric surface, a free curved surface, or the like may be used.
As shown in FIG. 4, the outer diameter of the lens 11 (the outer diameter of the lens side surface 11c) is D _L , and the length of the lens side surface 11c in the axial direction is t.
Examples of the material of the lens 11 include glass, plastic, crystal, ceramics, and the like.

As shown in FIG. 4, the frame 12 </ b> A is a substantially cylindrical frame that houses the lens 11. An adhesive container 12b, a fitting part 12a, a lens receiving part 12c, and an opening 12d are provided along the axial direction from the first end E1 to the second end E2 on the inner peripheral part of the frame 12A. Arranged in order.
The shape of the inner peripheral surface of the frame 12A is a rotationally symmetric shape with the central axis C of the frame 12A as the center.
For example, the center axis C may be defined as a center axis of a fitting portion 12a described later, or may be defined as a center axis of the outer peripheral surface 12f of the frame 12A. In the present embodiment, the central axis of the fitting portion 12a and the central axis of the outer peripheral surface 12f are coaxial.
The frame 12A may be held by a cylindrical exterior material (not shown).
In the exterior material or frame 12 </ b> A (not shown), a fixing portion (not shown) with the revolver 6 is formed at the end in the axial direction.

The fitting portion 12 a is a cylindrical hole portion that is fitted to the lens 11 so as to face the lens side surface 11 c of the lens 11. The inner diameter of the fitting portion 12a is D _H (where D _H > D _L ).
Therefore, fitting gap delta (second distance) between the lens side surface 11c and the fitting portion 12a is 0 or more _and less D H -D _L.
The inner diameter _{D H} of the adhesive receiving portion 12b, the value of the difference _(D H -D _L) between the outer diameter _{D L} of the lens 11 is set such that the allowable value of less than eccentric error of the lens 11 in the optical unit 10A May be.
However, for example, when the tolerance value of the eccentricity error is small as in an optical unit used in a microscope, the value of ( _DH− D _L ) is larger than the tolerance value of the eccentricity error of the lens 11 in the optical unit 10A. Is set. In this case, the lens 11 is fixed to the frame 12A in a state where at least the radial position is adjusted within the range of the fitting gap Δ. In this state after the position adjustment, the lens 11 is positioned at the approximate center (including the center) of the fitting portion 12a, so that the fitting gap Δ is substantially equal (including the case where it is equal) over the entire circumference. .
In any case, the lens optical axis O of the lens 11 fixed to the frame 12A and the center axis C of the frame 12A are coincident within the range of the allowable eccentric error of the lens 11.

The adhesive accommodating portion 12b is disposed adjacent to the fitting portion 12a in the axial direction. In the present configuration example, the adhesive accommodating portion 12b has a tapered surface whose diameter increases toward the first end portion E1 from the end portion (see point d) of the fitting portion 12a near the first end portion E1 on the inner peripheral portion. It is the formed hole.
The adhesive accommodating portion 12b forms a circular opening when viewed from the direction along the central axis C at the first end E1 of the frame 12A.
In the cross section including the central axis C, between the adhesive accommodating portion 12b and the fitting portion 12a adjacent to each other in the axial direction, and the lens side surface 11c facing these, between the lens side surface 11c and the adhesive accommodating portion 12b. The first distance in the radial direction is wider than the second distance between the lens side surface 11c and the fitting portion 12a.
In this configuration example, since the inner peripheral surface of the adhesive accommodating portion 12b is a tapered surface, the first interval in the adhesive accommodating portion 12b is in the axial direction from the second end E2 toward the first end E1. , Increase linearly.
The inclination angle θ of the inner peripheral surface of the adhesive accommodating portion 12b with respect to the central axis C may be greater than 45 ° and 60 ° or less.

The lens receiving portion 12c is a stepped portion that supports the second lens surface 11b of the lens 11 in the optical axis direction. The lens receiving portion 12c protrudes radially inward from the fitting portion 12a, and the shape viewed from the lens optical axis O is annular.
In the center of the lens receiving portion 12c has an opening 12d extends through the optical axis has a smaller diameter of the through hole than the outer diameter D _L of the lens 11.
A corner portion 12e formed by intersecting the lens receiving portion 12c and the opening portion 12d is in contact with the second lens surface 11b of the lens 11 inserted into the fitting portion 12a.
In FIG. 4, the surface of the lens receiving portion 12 c is drawn as a plane orthogonal to the central axis C. However, the shape of the surface of the lens receiving portion 12c is not limited to a flat surface as long as the shape does not contact the lens 11 except for the corner portion 12e. For example, it may be a concave surface that is recessed toward the second end E2 or may be a protrusion that protrudes toward the first end E1.
Further, FIG. 4 illustrates an example of a corner portion in which two straight lines intersect in a cross section including the central axis C, but the corner portion 12e is not limited to such an edge shape. For example, the corner portion 12e may be formed in a tapered shape in which such an edge portion is chamfered, or may be formed in a shape in which the edge portion is chamfered.
In the following, an example will be described in which the lens receiving portion 12c has a plane orthogonal to the central axis C and the corner portion 12e is not chamfered in accordance with the shape shown in FIG.

Next, the positional relationship between each part of the inner peripheral surface of the frame 12A having such a configuration and the lens 11 will be described.
The second lens surface 11b of the lens 11 is positioned in the optical axis direction in the frame 12A by coming into contact with a corner portion 12e formed by intersecting the lens receiving portion 12c and the opening portion 12d.
The axial position coordinates (hereinafter simply referred to as position coordinates) of the inner peripheral surface of the frame 12A will be described with the lens receiving portion 12c as a reference and the direction from the second end E2 to the first end E1 as the positive direction. Any character representing position coordinates represents a number of 0 or more.
The position coordinates of the corner portion 12e and the point e of the end portion near the second end portion E2 of the fitting portion 12a are both zero.
Position coordinate of a point where the second lens surface 11b and the lens side surface 11c intersect is _{h A.}
The position coordinate of the point b where the first lens surface 11a and the lens side surface 11c intersect is h _A + t.
The position coordinate of the point d at the end of the fitting portion 12a near the first end E1 is h _A + α.
The position coordinates of the first end E1, which is the end near the first end E1 of the adhesive accommodating portion 12b, are h _A + α + δ.

For this reason, the lens side surface 11c of the lens 11 positioned in the axial direction by the corner portion 12e faces the end portion near the first end E1 of the fitting portion 12a in the radial direction within the range of the axial length α. doing.
The axial length α at which the lens side surface 11c and the fitting portion 12a face each other is preferably as short as possible within a range in which the lens side surface 11c can be positioned in the radial direction by the fitting portion 12a.
For example, the length α may be greater than 0 mm and 3 mm or less. The length α is more preferably greater than 0 mm and not greater than 0.1 mm.

The lens side surface 11c has a range of axial length δ (see FIG. 4 when δ <t−α) or a range of axial length t (not shown when δ ≧ t−α). It faces the adhesive accommodating portion 12b in the radial direction.
Whether δ <t−α or δ ≧ t−α can be appropriately selected. For example, if it is necessary to fix the cured adhesive 13 described later to the entire lens side surface 11c in the axial direction, δ ≧ t−α may be satisfied.

The material of the frame 12A is not limited as long as it can hold the lens 11 with high accuracy. For example, examples of the material of the frame 12A include a metal material such as an aluminum alloy and stainless steel, a plastic material such as polycarbonate, and ceramics.
The frame 12A may be manufactured by cutting, or may be manufactured by molding using a molding die.

The adhesive cured body 13 is a member that is fixed to at least the surface of the adhesive accommodating portion 12b and the lens side surface 11c, and connects and fixes the adhesive accommodating portion 12b and the lens side surface 11c.
The adhesive cured body 13 is formed by applying an appropriate adhesive between the adhesive accommodating portion 12b and the lens side surface 11c and then curing.
Examples of the curing type of the adhesive that can be used to form the adhesive cured body 13 include a UV curable adhesive, a visible light curable adhesive, a thermosetting adhesive, a moisture curable adhesive, and an anaerobic curing. Mold adhesives, mixed curable adhesives, solvent volatile adhesives, and the like.
Examples of the adhesive material that can be used to form the cured adhesive 13 include acrylic adhesives, epoxy adhesives, urethane adhesives, rubber adhesives, and the like.

Since these adhesives are all liquid, when they are applied between the lens side surface 11c and the adhesive accommodating portion 12b, they also enter between the lens side surface 11c and the fitting portion 12a to some extent.
For example, if the viscosity of the adhesive is too low, there is a risk of exceeding the limit held by the surface tension between the lens side surface 11c and the fitting portion 12a. In this case, a part of the adhesive hangs down to the lens receiving portion 12c through the fitting portion 12a, but there is no problem unless it adheres to the lens effective area of the second lens surface 11b.
In the present embodiment, since the inner peripheral surface of the frame 12A is formed so that the length α is as short as possible according to the shape of the lens 11, as shown in FIG. 4, the lens side surface 11c and the fitting portion 12a. In many cases, the adhesive cured body 13 also enters a portion where and are opposed to each other.

The size of the adhesive cured body 13 in the optical unit 10A needs to have a fixed area with the lens side surface 11c and a fixed area with the adhesive accommodating portion 12b and the fitting portion 12a at a portion facing the lens side surface 11c. It is determined in advance so as to obtain an area where the adhesive strength can be obtained.
For example, the adhesive strength is preferably 10 N or more.
For simplicity, fixation area required, the lens side surface 11c side of the frame 12A side will be described as a fixation area S _0, respectively.

Fixation area S of the cured adhesive body 13 may take greater than fixation area S ₀ required. However, when the fixing area S is increased, the volume of the adhesive cured body 13 is also increased, and the influence of stress due to curing shrinkage is increased. For example, since the lens used for the objective lenses 5A and 5B of the microscope 1 requires high surface accuracy on the lens surface, it is preferable to reduce stress due to curing shrinkage as much as possible. Therefore, fixation area S of the cured adhesive body 13 should not exceed much larger fixation area S _0.
The fixing area S is distributed substantially evenly in the circumferential direction of the lens 11. The dispersion method may be discretely dispersed in the circumferential direction or may be continuously dispersed.
Since the stress due to the curing shrinkage of the adhesive cured body 13 is generated at the site where the adhesive cured body 13 is fixed, it is more preferable that the adhesive is continuously dispersed in that the influence of the stress can be averaged in the circumferential direction. .
In the present embodiment, the fixed area S is uniformly distributed in the circumferential direction by continuously forming the cured adhesive 13 over the entire circumference of the lens side surface 11c.

For example, as in Patent Document 1 described above, conventionally, when an optical element is bonded and fixed to a frame, an adhesive is applied over the entire axial direction in the gap between the lens side surface and the fitting portion. This is because the gap between the fitting portion for positioning in the radial direction and the lens side surface is extremely narrow, so it is necessary to make the adhesive low in viscosity, and this low viscosity adhesive fits the lens side surface by capillary action. It is because it is sucked into the gap with the part.
Conventionally, in the configuration in which the end of the fitting portion is chamfered in the frame, the chamfered portion has a function as an introduction port because the adhesive is introduced into the narrow fitting gap.

Conventionally, the adhesive between the lens side surface and the fitting portion and the adhesive remaining on the chamfered portion are considered to have similar curing shrinkage characteristics because they are the same material. However, the present inventor has intensively studied the adhesion and fixing of a lens that requires high surface accuracy. The adhesive between the lens side surface and the fitting portion and the adhesive remaining on the chamfered portion are hardened and contracted. The inventors have found that there is a difference in characteristics and have arrived at the present invention.
According to the inventor's study, the adhesive that is cured in a narrow gap such as the lens side surface and the fitting portion, for example, in a wider space, such as an adhesive applied to the chamfered portion, It has been found that cure shrinkage is more pronounced than adhesives applied to have a wide free surface.

The reason for this is not fully understood, but the present inventor believes that at least the following factors are involved.
The first factor is the size of the space where curing occurs. When the curing of the adhesive occurs in a certain wide space, spatial variation is likely to occur in the curing. That is, even when a part of the adhesive begins to harden, there is an uncured part around the part that has started to harden. For this reason, the part which began to harden | cure can move according to the fluidity | liquidity of an uncured part, and the stress which should generate | occur | produce by one part hardening is relieve | moderated with the movement of the part which began to harden | cure.
On the other hand, for example, an adhesive applied to a narrow gap such as the lens side surface and the fitting portion has a small amount of uncured portion in the narrow gap range even if there is a variation in curing, The part that has started to harden is difficult to move. For this reason, the above-mentioned stress relaxation effect becomes smaller.
The second factor is the stress relaxation effect due to the free surface. When the curing starts, the adhesive in the vicinity of the fixing surface such as the side surface of the lens is cured while being restrained by the fixing surface. On the other hand, the adhesive has a greater degree of freedom of deformation because there is no subject to be bound in the vicinity of the free surface. For this reason, even if the adhesive in the vicinity of the free surface undergoes shrinkage deformation, the stress is relaxed by the deformation of the free surface according to the amount of shrinkage.

Therefore, in the present embodiment, the adhesive forming the adhesive cured body 13 is applied more between the lens side surface 11c and the adhesive accommodating portion 12b than between the lens side surface 11c and the fitting portion 12a. In this state, the adhesive cured body 13 is formed.
In order to fix the adhesive cured body 13 having the fixing area S to the lens side surface 11c, the axial length of the fixing portion 13a fixed to the lens side surface 11c needs to be γ.
When the adhesive enters the entire fitting gap between the lens side surface 11c and the fitting portion 12a, the length γ of the fixing portion 13a is the axial length of the portion facing the fitting portion 12a in the radial direction. It is the sum of α and the axial length β (where β ≦ δ) of the bonded portion where the adhesive accommodating portion 12b faces in the radial direction.
For example, when the adhesive does not enter the fitting gap as in the case where the adhesive has a high viscosity, β = γ may be set.
Further, in the present embodiment, the adhesive cured body 13 is formed by applying an adhesive so that β> α in the fixing portion 13a. Thereby, in the adhesive cured body 13, a region where stress relaxation is more likely to proceed in the curing process is surely increased.
The difference between the length β and the length α is preferably as large as possible. However, since the stress due to curing shrinkage does not occur at all between the lens side surface 11c and the adhesive accommodating portion 12b, the upper limit value of β is determined in advance by an experiment or the like for a decrease in surface accuracy of the lens 11 or the like. It is better to set the value appropriately.
For example, the length β may be β> α, and may be greater than 0 mm and 5 mm or less. The length β is more preferably greater than 0 mm and not greater than 0.3 mm.

The cured adhesive 13 is exposed between the lens side surface 11c and the adhesive accommodating portion 12b toward the opening at the first end E1 formed by the adhesive accommodating portion 12b, and the lens side surface 11c and the adhesive accommodating portion. A free surface portion 13b that is not fixed to 12b is formed.
The length of the free surface portion 13b in the radial direction is larger than the fitting gap Δ because the surface of the adhesive accommodating portion 12b is configured by a tapered surface whose diameter is expanded from the fitting portion 12a.
For example, when the free surface portion 13b is formed along a plane orthogonal to the central axis C, the length of the free surface portion 13b in the radial direction is the sum of the fitting gap Δ and β · tan θ. .

An example of how to assemble the optical unit 10A having such a configuration will be described.
First, the lens 11 is inserted into the fitting portion 12a of the frame 12A so that the second lens surface 11b contacts the corner portion 12e of the frame 12A. Thereby, in the frame 12A, the lens 11 is positioned in the radial direction and the axial direction.
Thereafter, an adhesive that forms the adhesive cured body 13 in the circumferential direction is applied between the adhesive accommodating portion 12b and the lens side surface 11c. In the present embodiment, the adhesive is evenly applied over the entire circumference in the direction of the lens 11.
By appropriately setting the application amount of the adhesive, the length in the axial direction of the bonded portion that is opposed to the adhesive accommodating portion 12b in the radial direction in the fixing portion 13a of the adhesive cured body 13 becomes β as described above. To. Since the size of the space between the lens side surface 11c and the adhesive accommodating portion 12b is known in advance, the application amount for obtaining the above-described length β is, for example, constant with the discharge amount from the dispenser that discharges the adhesive. Are in a relationship.
Thereafter, the cured adhesive 13 is formed by curing the adhesive.
This completes the assembly of the optical unit 10A.

  In the example of the assembly method described above, an example in which the adhesive is applied after the lens 11 is inserted into the frame 12A has been described. However, the adhesive may be applied to at least one of the lens 11 and the frame 12A before the lens 11 is inserted.

According to the optical unit 10A, in the fixing portion 13a of the adhesive cured body 13 used for fixing the lens 11, the adhesive is accommodated rather than the length (length α or less) of the portion facing the fitting portion 12a in the radial direction. The length (length β) of the portion facing the portion 12b in the radial direction is longer. As a result, the generation of stress due to curing shrinkage in the curing process of the adhesive cured body 13 is reduced.
In the optical unit 10 </ b> A, the lens 11 is fixed by the adhesive cured body 13, so that sufficient adhesive strength is provided. Furthermore, in the adhesive cured body 13, since the generation of stress acting on the lens side surface 11c due to curing shrinkage is small, distortion of the lens 11 can be suppressed. As a result, since the change of the surface accuracy of the first lens surface 11a and the second lens surface 11b of the lens 11 can be suppressed, the optical performance as the optical unit 10A becomes good.

  As described above, according to the optical unit 10A, it is possible to reduce the distortion of the lens 11 that is an optical element without reducing the adhesive strength.

Next, a second configuration example of the optical unit 10 of the present embodiment will be described.
FIG. 5 is a schematic cross-sectional view of the cross section including the optical axis showing a second configuration example of the optical unit according to the first embodiment of the present invention. FIG. 6 is an enlarged view of a portion D in FIG.

As shown in FIGS. 5 and 6, the optical unit 10B as the second configuration example includes a lens 14 (optical element), a frame 12B in which the lens 14 is inserted, and an adhesive that fixes the lens 14 to the frame 12B. And a cured body 13.
This configuration example is different from the lens 11 in that the lens 11 in the first configuration example is a biconvex lens, whereas the lens 14 is a meniscus lens.
The lens 14 may be a positive meniscus lens or a negative meniscus lens. When the lens 14 is a negative meniscus lens, the lens 14 is used in combination with a positive lens (not shown) as the objective lenses 5A and 5B.
The following description will focus on differences from the first configuration example.

  As shown in FIG. 5, the lens 14 has a first lens surface 14a made of a concave surface and a second lens surface 14b made of a convex surface. A lens side surface 11c similar to that of the first configuration example is formed on the outer peripheral portion between the first lens surface 14a and the second lens surface 14b.

The frame 12B is the same member as the frame 12A except that the second lens surface 14b of the lens 14 is placed and fixed. For this reason, except that the position coordinate h _B measured from the lens receiving portion 12c at the point a where the second lens surface 14b and the lens side surface 11c intersect in the lens 14 is different from h _{A in} the first configuration example, A configuration similar to that of the frame 12A is provided.

The adhesive cured body 13 in this configuration example is formed in the same positional relationship as the first configuration example with respect to the lens side surface 11c of the lens 14.
Such an optical unit 10B can be assembled in the same manner as the optical unit 10A of the first configuration example.
Since the optical unit 10B can suppress a change in surface accuracy of the first lens surface 14a and the second lens surface 14b by the adhesive cured body 13 just like the optical unit 10A, the optical performance as the optical unit 10B is good. It becomes.

  The meniscus lens, particularly the negative meniscus lens, has a longer length t in the axial direction of the lens side surface 11c than a biconvex lens. For this reason, when the entire lens side surface 11c is bonded and fixed, the distortion of the lens tends to be particularly large. However, according to the present configuration example, the fixing portion 13a is formed in the range of the required adhesive strength regardless of the axial length t of the lens side surface 11c, so that the distortion of the lens 14 is suppressed.

Next, the 3rd structural example of the optical unit 10 of this embodiment is demonstrated.
FIG. 7 is a schematic cross-sectional view including the optical axis showing the main part of the third configuration example of the optical unit according to the first embodiment of the present invention.

As shown in FIG. 7, the optical unit 10 </ b> C as a third configuration example includes a parallel plate-like ND filter 15 (optical element), a frame 12 </ b> C in which the ND filter 15 is inserted, and an ND filter. And an adhesive cured body 13 for fixing 15 to the frame 12C.
Although not particularly illustrated, the optical unit 10C is used as an observation optical system in combination with appropriate lenses (for example, the objective lenses 5A and 5B) constituting the objective optical system.
Since the ND filter 15 of the present configuration example is a parallel plate, unlike the lens 11 of the first configuration example placed on the corner portion 12e, the ND filter 15 is received in a planar shape by the lens receiving portion 12c. Is different from the lens 11.
The following description will focus on differences from the first configuration example.

  As shown in FIG. 7, the ND filter 15 has a first filter surface 15a and a second filter surface 15b that are parallel to each other. On the outer periphery between the first filter surface 15a and the second filter surface 15b, a filter side surface 15c (side surface of the optical element) similar to the lens side surface 11c of the first configuration example is formed.

The frame 12C is a member similar to the frame 12A except that the second filter surface 15b of the ND filter 15 is placed and fixed on the lens receiving portion 12c. Therefore, a position coordinate 0, measured from the second filter surface 15b and the filter side of 15c and meet point a lens receiving portion 12c of the ND filter 15, a h _A differs from the first configuration Except for this, it has the same configuration as the frame 12A.

The cured adhesive body 13 in this configuration example is formed in the same positional relationship with respect to the filter side surface 15c in the ND filter 15 as the lens side surface 11c in the first configuration example.
In the first configuration example, only the upper end portion of the fitting portion 12a faces the lens side surface 11c. However, in the present configuration example, the whole fitting portion 12a faces the filter side surface 15c. In the present configuration example, the lower end of the fitting gap between the filter side surface 15c and the fitting portion 12a is closed by the lens receiving portion 12c.
Such an optical unit 10C can be assembled in the same manner as the optical unit 10A of the first configuration example.
Since the optical unit 10C can suppress changes in the surface accuracy of the first filter surface 15a and the second filter surface 15b by the adhesive cured body 13 just like the optical unit 10A, the optical performance as the optical unit 10C is good. It becomes.

  As described above, according to the microscope 1 that uses the optical units 10A, 10B, and 10C of the present embodiment as, for example, the objective lenses 5A and 5B, or together with the objective lenses 5A and 5B, the optical unit having excellent optical performance. 10A enables high-precision observation.

[Second Embodiment]
An optical unit according to a second embodiment of the present invention will be described.
FIG. 8 is a schematic cross-sectional view including the optical axis showing the main part of the fourth configuration example of the optical unit according to the second embodiment of the present invention.

FIG. 8 shows an optical unit 20A that is a fourth configuration example of the optical unit 20 of the present embodiment.
The optical unit 20A includes a frame 22A instead of the frame 12B of the optical unit 10B of the second configuration example of the first embodiment.
Hereinafter, a description will be given centering on differences from the first embodiment.

The frame 22A includes a fitting portion 22a instead of the fitting portion 12a of the frame 12B of the second configuration example, and is configured by adding an enlarged diameter portion 22e.
Hereinafter, a description will be given centering on differences from the first embodiment.

The surface of the fitting portion 22a is a cylindrical surface having the same inner diameter as the fitting portion 12a of the second configuration example.
The fitting part 22a is sandwiched between the adhesive accommodating part 12b and the diameter-enlarged part 22e described later, which are adjacent in the axial direction. The axial length of the fitting portion 22a is equal to the length α of the frame 12B in the second configuration example. That is, in a cross section including the central axis C, a point where the adhesive accommodating portion 12b and the fitting portion 12a intersect is a point d, and a point where the fitting portion 12a and a diameter-enlarged portion 22e described later intersect is a point f. The length of the minute df is equal to α.

The fitting portion 22a of this configuration example is disposed at an appropriate position facing the lens side surface 11c of the lens 14 in the radial direction. That is, the position coordinates measured in the axial direction from the lens receiving portion 12c of the point f, or h _B, it is less than t-alpha. In the example shown in FIG. 8, as an example, the fitting portion 22 a is opposed to the lens side surface 11 c in the radial direction at an intermediate portion in the axial direction of the lens side surface 11 c.

The enlarged diameter portion 22e is disposed on the opposite side of the adhesive accommodating portion 12b in the axial direction at a portion adjacent to the fitting portion 22a in the inner peripheral portion of the frame 22A.
The enlarged diameter portion 22e has a shape in which the third interval between the lens side surface 11c of the lens 14 in the radial direction is wider than the fitting gap (second interval) between the lens side surface 11c and the fitting portion 22a. Is formed.
In the example shown in FIG. 8, the enlarged diameter portion 22e is configured by an inclined surface portion 22c and a cylindrical surface portion 22d arranged in this order from the first end E1 toward the second end E2.
The inclined surface portion 22c is a tapered surface that gradually increases in diameter from the fitting portion 22a toward the cylindrical surface portion 22d.
The cylindrical surface portion 22d has the same inner diameter as the maximum inner diameter of the inclined surface portion 22c and extends to the lens receiving portion 12c.
For this reason, the enlarged diameter part 22e comprises the recessed part in radial direction with respect to the fitting part 22a.

  The cured adhesive body 13 in the present embodiment is formed in the same manner as in the second configuration example except that the position in the axial direction with respect to the lens side surface 11c of the second configuration example in the first embodiment is shifted. ing.

The optical unit 20A having such a configuration is manufactured in the same manner as the optical unit 10B of the first embodiment.
However, when the adhesive forming the adhesive cured body 13 hangs down to the second end E2 side from the fitting gap between the lens side surface 11c and the fitting portion 22a, at least a part of the adhesive is along the inclined surface portion 22c. Move.
For this reason, when the surface area of an adhesive expands, dripping is easily stopped by surface tension. In addition, at least a part of the sagging adhesive is guided toward the cylindrical surface portion 22d farther from the lens side surface 11c via the inclined surface portion 22c, so that the sagging adhesive hardly adheres to the lens 14.

  The optical unit 20A of this configuration example manufactured in this way is exactly the same as the optical unit 10B of the second configuration example except that the formation position of the adhesive cured body 13 in the axial direction of the lens side surface 11c is different. An adhesive cured body 13 is formed. For this reason, the optical unit 20A can reduce the distortion of the lens 11 that is an optical element without reducing the adhesive strength, as in the second configuration example.

Next, a fifth configuration example of the optical unit 20 of the present embodiment will be described.
FIG. 9 is a schematic cross-sectional view including the optical axis showing the main part of the fifth structural example of the optical unit according to the second embodiment of the present invention.

As shown in FIG. 9, the optical unit 20B as the fifth configuration example includes a fitting portion 22b instead of the fitting portion 22a of the optical unit 20A according to the fourth configuration example.
The fitting portion 22b is formed by intersecting the adhesive accommodating portion 12b and the inclined surface portion 22c of the enlarged diameter portion 22e, and is configured by a mountain-shaped top portion in a cross section including the central axis C. The shape of the fitting portion 22b viewed from the axial direction is a circle having an inner diameter _DH .
The fitting portion 22b is an example in which the axial length of the fitting portion 22a of the fourth configuration example is zero.

Such an optical unit 20B is manufactured in the same manner as the optical unit 20A of the fourth configuration example.
According to the optical unit 20, the adhesive cured body 13 is formed only in a region sandwiched between the lens side surface 11c and the adhesive accommodating portion 12b. Since the fitting portion 22b has an axial length of 0, it does not contribute to the generation of stress due to the curing shrinkage of the adhesive cured body 13 at all. For this reason, compared with the said 4th structural example, generation | occurrence | production of the stress by the cure shrinkage of the adhesive agent hardening body 13 can be reduced further.
In the present configuration example, when the lens 14 moves in the radial direction, the fitting portion 22b comes into contact with the intermediate portion of the lens side surface 11c, so that the radial movement range of the lens 14 is reliably restricted. For this reason, even if the axial length of the fitting portion 22b is zero, the position of the lens 14 is restricted in the radial direction by the fitting portion 22b.
The fitting portion 22b does not contribute to the axial length of the fixing portion 13a, but the length β of the fixing portion 13a is not less than the length γ required for the bonding strength, so that the bonding strength is increased. There is no decline.
Therefore, the optical unit 20B can reduce the distortion of the lens 11 that is an optical element without reducing the adhesive strength.

  As shown in FIG. 1, the optical unit 20 of the present embodiment can be used as the objective lenses 5 </ b> A and 5 </ b> B in the microscope 1, for example, similarly to the optical unit 10 of the first embodiment.

In the above description of each embodiment, the optical unit of the optical unit is described as an example of an ND filter that is a biconvex lens, a meniscus lens, or a parallel plate. However, these optical elements are examples. The kind of optical element is not limited to these.
For example, the optical element may be a lens other than the above, for example, a biconcave lens, a plano-convex lens, a plano-concave lens, a Fresnel lens, a hologram element, or a parallel plate-shaped optical member including a filter other than the ND filter.
For example, the optical element may be a flanged lens. In this case, the cured adhesive body in the flange portion may be formed in the same shape as the third configuration example of the first embodiment.
Furthermore, the optical element may be an appropriately shaped prism, mirror, or the like.

In the description of each of the above-described embodiments, an example in which the surface of the adhesive accommodating portion is configured by a tapered surface has been described. However, the adhesive accommodating portion is configured by a tapered surface if the first interval with the side surface of the optical element is larger than the second interval between the side surface of the optical element and the fitting portion. It does not have to be.
For example, the adhesive accommodating part may be configured by a curved surface whose shape in a cross section including the central axis is a curved line such as an arc shape.
For example, the adhesive accommodating part may have a stepwise pseudo slope in the cross section including the central axis.
For example, the adhesive accommodating portion may be configured by a cylindrical surface whose first distance from the side surface of the optical element is a constant value larger than the second distance between the side surface of the optical element and the fitting portion. Good. Such a shape can be formed by, for example, counterboring.
For example, the adhesive container may have a configuration in which the various shapes described above are appropriately combined.

  In the above description of each embodiment, an example in which the optical element is circular when viewed from the axial direction has been described. However, the shape of the optical element viewed from the axial direction is not limited to a circular shape. For example, the shape of the optical element viewed from the axial direction may be an appropriate shape such as a D shape, a rectangular shape, or an elliptical shape. Correspondingly, the shape of the inner peripheral portion of the frame can be appropriately set according to the optical element.

  In the above description of each embodiment, an example in which the optical unit is a coaxial optical system has been described. However, the optical unit may be a decentered optical system.

  In the above description of each embodiment, an example in which the frame includes a lens receiving portion has been described. However, a configuration without the lens receiving portion is also possible. For example, when the optical element is bonded to the frame in the air, the lens receiving portion may not be provided.

In the description of the second embodiment, the example in which the enlarged diameter portion 22e is configured by the inclined surface portion 22c and the cylindrical surface portion 22d has been described. However, the shape of the enlarged diameter portion is larger than that of the fitting portion. If it is, it is not limited to this.
For example, the diameter-enlarged portion may be configured only by a tapered surface such as the inclined surface portion 22c.
For example, the diameter-enlarged portion may have a stepwise pseudo slope in the cross section including the central axis.
For example, the diameter-enlarged portion is a curved surface whose cross-sectional shape including the central axis C is other than a straight line, for example, a curved surface whose cross-sectional shape including the central axis C is a non-straight curved surface, for example, a curved surface such as an arc. It may be formed.

  Examples 1 to 7 of the above embodiments will be described together with Comparative Example 1.

[Example 1]
Example 1 is an example of the first configuration example of the first embodiment.
As the lens 11, a polished glass biconvex lens with D _L = 20 (mm) and t = 3 (mm) was used. The curvature radii of the first lens surface 11a and the second lens surface 11b were 25 mm and 20 mm, respectively.
As the material of the lens 11, S-FPL51 (trade name; manufactured by OHARA INC.) Was used.
In the frame 12A, the inclination angle θ of the adhesive accommodating portion 12b is 46 °, and the inner diameter of the fitting portion 12a is D _H = 20.02 (mm).
The axial length in which the lens side surface 11c and the fitting portion 12a face each other was α = 0.1 (mm).
The material of the frame 12A was brass.
As the adhesive that forms the cured adhesive 13, World Lock (registered trademark) 8802H (trade name; manufactured by Kyoritsu Chemical Industry Co., Ltd.), which is a UV curable adhesive, was used.
The optical unit 10A of Example 1 was manufactured by adhering the lens 11 to the frame 12A using a UV curable adhesive.
The viscosity of the UV curable adhesive was such that it entered the fitting gap between the lens side surface 11c and the fitting portion 12a, but not so much as to leak into the lens receiving portion 12c along the fitting portion 12a. . An LED light source was used for curing the UV curable adhesive, the illuminance was 50 mW / cm 2, and the irradiation time was 100 seconds.
The adhesive cured body 13 had β = 0.3 (mm).

[Examples 2 and 3]
Example 2 is different from Example 1 only in that the inclination angle of the adhesive accommodating portion 12b of the frame 12A is set to 60 °.
Example 3 is different from Example 1 only in that the adhesive cured body 13 is formed of Hisuper (registered trademark) 30 (trade name; manufactured by Cemedine Co., Ltd.), which is a thermosetting epoxy adhesive. Since the viscosity of the thermosetting epoxy adhesive was higher than the viscosity of the UV curable adhesive, it was unclear whether it entered the entire fitting gap between the lens side surface 11c and the fitting portion 12a.

[Example 4]
Example 4 is an example of the second configuration example.
As the lens 14, a polished glass concave meniscus lens with D _L = 18 (mm) and t = 4 (mm) was used. The curvature radii of the first lens surface 14a and the second lens surface 14b were 12 mm and 20 mm, respectively.
As a material of the lens 14, S-LAM54 (trade name; manufactured by OHARA INC.) Was used.
In the frame 12B, the inclination angle θ of the adhesive accommodating portion 12b is 46 °, and the inner diameter of the fitting portion 12a is D _H = 18.02 (mm).
The axial length in which the lens side surface 11c and the fitting portion 12a face each other was α = 0.1 (mm).
The adhesive cured body 13 was formed using the same UV curable adhesive as in Example 1 so as to have the same length β as in Example 1.

[Examples 5 and 6]
Examples 5 and 6 are examples of the fourth and fifth configuration examples, respectively.
The lens 14 has the same shape as that of the fourth embodiment.
In the frame 22A of Example 5, the inclination angle θ of the adhesive accommodating portion 12b was 46 °, and the dimensions of the fitting portion 22a were D _H = 18.02 (mm) and α = 0.1 (mm). .
In the frame 22B of Example 6, the inclination angle θ of the adhesive accommodating portion 12b was 46 °, and the dimensions of the fitting portion 22b were D _H = 18.02 (mm) and α = 0 (mm).
The adhesive cured body 13 was formed using the same UV curable adhesive as in Example 1 so as to have the same length β as in Example 1.

[Example 7]
Example 7 is an example of the third configuration example.
As the ND filter 15, a parallel plate made by Sigma Koki Co., Ltd. with D _L = 25 (mm) and t = 2 (mm) was used.
In the frame 12C, the inclination angle θ of the adhesive accommodating portion 12b is 46 °, and the dimensions of the fitting portion 12a are _DH = 25.02 (mm) and α = 0.2 (mm).
The adhesive cured body 13 was formed using the same UV curable adhesive as in Example 1 so as to have the same length β as in Example 1.

[Comparative Example 1]
Comparative Example 1 is the same as Example 1 except that α = 0.4 (mm).
That is, Comparative Example 1 is an example that does not satisfy β> α.

[Evaluation]
In each of Examples 1 to 7 and Comparative Example 1, the adhesive strength and the change in surface accuracy of the optical element before and after assembly were evaluated.
Adhesive strength was evaluated by applying a load of 10 N in the direction of the optical axis in the direction in which the prototype optical element was removed, and whether the optical element was removed from the frame.
For the evaluation of the change in distortion, the surface accuracy of each optical element before assembly is measured by a small laser interferometer KIF-201 (trade name; manufactured by Olympus Corporation), and the surface accuracy of the optical element after assembly is made the same. And ΔPV which is the PV value of the amount of change from the surface accuracy of the optical element before assembly to the surface accuracy after assembly.

[Evaluation results]
In the evaluation of the adhesive strength, none of the optical elements of Examples 1 to 7 and Comparative Example 1 was out of the frame. For this reason, the optical units of Examples 1 to 7 and Comparative Example 1 all had sufficient adhesive strength.

The ΔPVs of Examples 1 to 3 were 0.1λ, 0.08λ, and 0.13λ, respectively.
The surface accuracy of Example 2 was better than that of Example 1 having an inclination angle of 46 ° because the inclination angle of the adhesive accommodating portion 12b was 60 °.
In Example 3, the change in surface accuracy was larger than that in Example 1 due to the use of a thermosetting epoxy resin adhesive. However, since the surface accuracy was less than 0.2λ, the surface accuracy was good.
The ΔPVs of Examples 4 to 6 were 0.09λ, 0.09λ, and 0.08λ, respectively.
Examples 4 and 5 are common in that α = 0.1 (mm), and the change in surface accuracy is also the same.
On the other hand, in Example 6, since α = 0 (mm), the change in surface accuracy was even better than in Examples 4 and 5.
The ΔPV of Example 7 was 0.06λ.
Thus, the changes in surface accuracy of Examples 1 to 7 were all good.
On the other hand, ΔPV of Comparative Example 1 was 0.21λ and exceeded 0.20λ. For this reason, it was a level which cannot be used for the optical apparatus which requires high surface precision, such as a microscope, for example.

The preferred embodiments, configuration examples, and examples of the present invention have been described above, but the present invention is not limited to such embodiments, configuration examples, and examples. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit of the present invention.
Further, the present invention is not limited by the above description, and is limited only by the appended claims.

1 Microscope (optical equipment)
5A, 5B Objective lens (optical unit)
7 Eyepiece 8 Camera 9A, 9B Illumination device 10, 10A, 10B, 10C, 20, 20A, 20B Optical unit 11, 14 Lens (optical element)
11b, 14b Second lens surface 11c Lens side surface (side surface of optical element)
12A, 12B, 12C, 22A, 22B Frames 12a, 22a, 22b Fitting portion 12b Adhesive accommodating portion 12c Lens receiving portion 12e Corner portion 13 Adhesive cured body 13a Adhering portion 13b Free surface portion 15 ND filter (optical element)
15b Second filter surface 15c Filter side surface (side surface of optical element)
22e Expanded diameter portion C Center axis E1 First end E2 Second end L Optical axis O Lens optical axis Δ Fitting gap (second interval)

Claims (6)

An optical element;
A frame in which the optical element is inserted;
A fitting portion that is disposed on an inner peripheral portion of the frame and that is fitted to the optical element so as to face a side surface of the optical element;
The inner peripheral portion of the frame is disposed adjacent to the fitting portion in a direction along the central axis of the side surface of the optical element, and a first interval with the side surface in the radial direction is in the radial direction. An adhesive accommodating portion wider than a second distance between the side surface and the fitting portion;
An adhesive hardened body that is fixed to at least the surface of the adhesive accommodating portion and the side surface of the optical element, and connects and fixes the surface of the adhesive accommodating portion and the side surface of the optical element; ,
With
The length along the central axis of the portion where the side surface of the optical element and the fitting portion oppose each other in the radial direction is opposed to the adhesive accommodating portion in the radial direction in the cured adhesive body. Shorter than the length along the central axis of the bonded portion fixed to the side portion of the optical element,
Optical unit. The adhesive container is
The portion adjacent to the fitting portion includes a tapered surface having an inclination angle with respect to the central axis of the fitting portion of greater than 45 ° and 60 ° or less.
The optical unit according to claim 1. The adhesive container is
The portion adjacent to the fitting portion includes a curved surface having a curved section including the central axis.
The optical unit according to claim 1. The fitting portion, the adhesive accommodating portion, and the adhesive cured body are:
Each is formed along the entire circumference of the side surface of the optical element,
The optical unit of any one of Claims 1-3. In the inner periphery of the frame, adjacent to the fitting portion in the axial direction and positioned on the opposite side of the adhesive accommodating portion, a third distance from the side surface of the optical element in the radial direction is the second distance. An enlarged diameter part wider than the interval is formed,
The optical unit of any one of Claims 1-4. The optical unit according to claim 1 is provided.
Optical equipment.

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