JP2009069315A - Optical element assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To fixedly hold an optical element in a cylinder body while maintaining desired optical performance. <P>SOLUTION: An optical element assembly 10 has a lens 12 fixedly held in the cylinder body 20. The lens 12 has a projection 14 projecting in a direction orthogonal to an optical axis, at the outer peripheral part 16 thereof, and clamping pieces 28 which clamp the projection 14 of the lens 12 with a prescribed pressure from both sides in the direction of the optical axis are provided to the cylinder body 20. The projection 14 of the lens 12 is press-fit to the clamping piece 28 and is fixedly held. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical element assembly in which an optical element such as a lens is fixed in a cylinder.

  Many optical elements such as lenses are made of glass or synthetic resin. Therefore, it is difficult to directly attach such an optical element to an optical device with a fixture such as a bolt. For this reason, the optical element is mounted in advance on a casing or cylinder made of, for example, an elastic member by means such as press fitting or heat caulking, and the casing or cylinder is attached to the optical apparatus.

Conventionally, for example, a technique disclosed in Patent Document 1 is known as a lens assembly in which an optical element such as a lens is fixed inside a cylinder.
In Patent Document 1, a thin part is formed at the edge of one opening end of a lens barrel that holds a lens, and the lens is press-fitted into the thin part from the outside of the lens barrel using a press-fitting jig and assembled. Yes.
Japanese Patent Laid-Open No. 6-160685

  However, in Patent Document 1, the outer diameter of the lens and the inner diameter of the thin portion formed in the lens barrel must be processed with high accuracy. Otherwise, stress is generated inside the lens when the lens is pressed into the thin part of the lens barrel. In particular, when a compression force or the like is applied from a direction orthogonal to the optical axis of the lens, the lens is deformed. This deformation causes a problem that the lens cannot exhibit the desired optical performance.

  SUMMARY An advantage of some aspects of the invention is that it provides an optical element assembly capable of fixing and holding an optical element in a cylinder while maintaining desired optical performance.

In order to achieve the object, the invention according to claim 1
An optical element assembly in which an optical element is fixedly held in a cylinder,
The optical element has a protrusion protruding in a direction perpendicular to the optical axis on the outer periphery,
The cylindrical body has a clamping portion that sandwiches the projection of the optical element at a predetermined pressure from both sides in the optical axis direction on the inside,
The protrusion is press-fitted into the pinching portion and fixedly held.

The invention according to claim 2 is the optical element assembly according to claim 1,
The projection is characterized in that at least one of the two surfaces in the optical axis direction sandwiched by the clamping unit is formed into a curved surface.

The invention according to claim 3 is the optical element assembly according to claim 1 or 2,
A plurality of the optical elements fixed and held in the cylindrical body are provided, and the plurality of optical elements have a larger outer diameter in order from one direction.

The invention according to claim 4 is the optical element assembly according to any one of claims 1 to 3,
In a state where the protrusion is press-fitted into the pinching portion, an end surface of the protrusion in a direction orthogonal to the optical axis is not in contact with the inner peripheral surface of the cylindrical body.

The invention according to claim 5 is the optical element assembly according to any one of claims 1 to 4,
The cylinder is made of resin.

  According to the present invention, the optical element has a protrusion on the outer peripheral portion, and the cylindrical body has a pinching portion that sandwiches the protrusion from both sides, and the protrusion is press-fitted into the pressing portion and fixedly held. Thus, it is possible to obtain an optical element assembly in which the optical element is fixed and held in the cylinder while maintaining desired optical performance.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a plan view of the optical element assembly, and FIG. 2 is a sectional view taken along line II-II.

  The optical element assembly 10 includes a cylindrical body 20 and a lens 12 as an optical element fixedly held in the cylindrical body 20. The cylindrical body 20 has a substantially cylindrical shape (brown shape), and is made of a synthetic resin such as polycarbonate. However, the shape and material are not limited to this. For example, the cylindrical body 20 may be a rectangular cylinder, and the material may be made of metal. In the case of being made of metal, the amount of elastic deformation is smaller than that of synthetic resin, so the press-fitting allowance with the lens 12 needs to be reduced.

  As shown in FIG. 2, the inner side of the cylindrical body 20 has a stepped cross section from one end to the other end in the axial direction (OO axial direction). That is, the inner side of the cylindrical body 20 is larger in diameter than the opening 22 through the opening 22 and the stepped surface 23 substantially equal to the effective diameter of the lens 12 in order from one end in the axial direction (the lower end in FIG. 2). A lens fitting hole 24 substantially equal to the outer diameter (diameter of the outer peripheral portion 16 (see FIG. 3)) and a lens insertion hole 26 having a larger diameter than the lens fitting hole 24 are formed via a step surface 25. .

  On the inner peripheral surface of the lens insertion hole 26, three pressing pieces 28 as pressing parts are formed so as to protrude toward the axial center (OO) side. The pinching pieces 28 are formed at substantially equal intervals of a predetermined length along the circumferential direction.

  A predetermined gap h is formed between the pinching piece 28 and the step surface 25 in the axial direction (O-O axial direction). The lens 12 is press-fitted with a predetermined pressure between the pinching piece 28 and the step surface 25 and fixed. The lens 12 is fixedly held on the cylinder 20 so that the optical axis thereof substantially coincides with the axis (OO) of the cylinder 20.

FIG. 3 is a front view of the lens 12, and FIG. 4 is a cross-sectional view taken along IV-IV.
The lens 12 is a biconvex lens having optical function surfaces 12a and 12b having different curvature radii. This lens 12 has three protrusions 14 protruding in a direction perpendicular to the optical axis on a cylindrical outer peripheral portion 16. In the present embodiment, the three protrusions 14 are formed at substantially equal intervals of 120 °. The thickness of the projection 14 (thickness in the optical axis direction) is formed to be smaller than the thickness of the outer peripheral portion 16.

  Specifically, the dimensions of the lens 12 are, for example, the diameter φ of the outer peripheral portion 16 is φ = 15 mm, the protrusion amount s of the protrusion 14 is s = 1 to 2 mm, and the thickness h ′ of the protrusion 14 is h ′ = 1 mm ( +2 μm to +7 μm).

  This thickness h ′ is formed to be substantially equal to the gap h between the sandwiching piece 28 and the step surface 25 described above. However, h ′> h is formed so that the lens 12 can be press-fitted and fixed. Specifically, the gap h between the pinching piece 28 and the step surface 25 is formed as h = 1 mm (−0 to −5 μm). Thereby, the lens 12 is press-fitted between the pressing piece 28 and the step surface 25 and fixed.

  The lens 12 has a cylindrical body so that the optical axis of the lens 12 and the axis of the cylindrical body 20 coincide when the projection 14 is press-fitted between the pinching piece 28 and the stepped surface 25. 20 is fixedly held. For this purpose, the outer peripheral portion 16 of the lens 12 and the inner peripheral surface of the lens fitting hole 24 of the cylindrical body 20 are processed with high precision so that they can be fitted together. Further, the outer peripheral portion 16 of the lens 12 is processed (centered) with high accuracy so as to coincide with the optical axis.

  Further, the end surface 15 (see FIG. 4) in the direction orthogonal to the optical axis of the projection 14 in the state where the projection 14 of the lens 12 is press-fitted between the pinching piece 28 and the step surface 25 is a cylindrical body 20. This is not in contact with the inner peripheral surface 21 (see FIG. 2) and is not in contact with the inner peripheral surface 21 (see FIG. 2). This is because when the end surface 15 of the projection 14 comes into contact with the inner peripheral surface 21 of the cylindrical body 20, stress in a direction perpendicular to the optical axis is generated on the lens 12.

FIG. 5 is a view in the direction of the arrow V in FIG.
That is, the projection 14 of the lens 12 is formed such that the upper surface 14a of the upper surface 14a and the lower surface 14b on both sides in the optical axis direction press-fitted between the pinching piece 28 and the step surface 25 is a curved surface having a predetermined radius of curvature. The lower surface 14b is formed in a plane.

  Accordingly, as shown in FIG. 6, the protrusion 14 press-fitted between the pinching piece 28 and the step surface 25 has an upper surface 14 a that contacts the lower surface 28 a of the pinching piece 28, and a lower surface 14 b that faces the step surface 25. Abut. In this case, since the upper surface 14a is formed in a curved surface, the protrusion 14 smoothly moves in the direction of the arrow and is press-fitted while changing the inclination in small increments without being caught between the upper surface 14a and the lower surface 28a of the pressing piece 28. The Further, since the lower surface 28a of the protrusion 14 is formed into a flat surface, it is easy to make the optical axis of the lens 12 coincide with the axis of the cylindrical body 20 when the lens 12 is press-fitted.

In the present embodiment, a curved surface is formed on the upper surface 14a, but the present invention is not limited to this. For example, the upper surface 14a may be formed as a flat surface, and the curved surface may be formed as the lower surface 14b.
FIG. 7A is a front view of a press-fitting jig for the lens 12, and FIG. 7B is a side view thereof.

  The press-fitting jig 30 has a main body portion 32 and a grip portion 34. The main body 32 has a cylindrical shape, and three pins 36 arranged at substantially equal intervals of 120 ° in the circumferential direction protrude in the axial direction on one end face thereof. The grip part 34 is a part that the operator grips.

  In order to attach the lens 12 to the cylindrical body 20 using the press-fitting jig 30, the lens 12 is pinched by hand or tweezers so that the optical axis of the lens 12 is substantially parallel to the axial center of the cylindrical body 20. Hold. Next, the lens 12 is inserted into the lens insertion hole 26 of the cylindrical body 20. At this time, the lens 12 is appropriately rotated in the circumferential direction and moved so that the projection 14 of the lens 12 and the pressing piece 28 of the cylindrical body 20 do not interfere with each other. Then, the projection 14 of the lens 12 is placed on the step surface 25. In this state, the lens 12 can freely rotate in the circumferential direction while being placed on the step surface 25.

  Next, the grip portion 34 of the press-fitting jig 30 is gripped, and the three pins 36 are positioned so as to contact the side surface 14c or 14d (see FIG. 3) of the projection 14 of the lens 12. In this state, the press-fitting jig 30 is rotated clockwise or counterclockwise to apply a rotational force to the lens 12. Thereby, the projection 14 of the lens 12 is press-fitted with a predetermined pressure into the gap h between the pressing piece 28 and the stepped surface 25. In this case, as described above, the protrusion 14 is press-fitted into the gap h relatively smoothly because the upper surface 14a is formed in a curved surface.

FIG. 8 is a diagram illustrating a stress state applied to the lens 12 in the conventional example, and FIG. 9 is a diagram illustrating a stress state applied to the lens 12 in the present embodiment.
As shown in FIG. 8, in the conventional example, when the lens 12 is press-fitted into the cylindrical body 20, a radial force (compression force) P acts on the outer peripheral portion of the lens 12 from the cylindrical body 20 side. In this case, due to the acting force P, a stress (tensile stress) σ acts on the optical function surfaces 12a and 12b of the lens 12 in the direction of the arrow in the figure (optical axis direction). This stress σ is large on the outer diameter side of the lens 12 and small on the center side. For this reason, the lens 12 is deformed in the optical axis direction. This changes the optical performance.

  On the other hand, as shown in FIG. 9, in this embodiment, the tip end portion of the protrusion 14 of the lens 12 and the inner peripheral surface of the lens insertion hole 26 of the cylindrical body 20 are not in contact with each other. No radial force acts on the outer periphery of the lens 12 from the cylinder 20 side when pressed into the tube 20. A force (compression force) Q in the optical axis direction acts on the upper surface 14 a and the lower surface 14 b of the projection 14 of the lens 12 from the pinching piece 28 and the step surface 25 of the cylindrical body 20. Due to this force Q, a radial stress (tensile stress) σ ′ is generated in the lens 12. However, the stress σ ′ is small and the stress σ ′ is released as deformation in the outer diameter direction of the lens 12. For this reason, the optical performance is not affected.

According to the present embodiment, the projection 12 formed on the outer peripheral portion of the lens 12 is press-fitted between the pinching piece 28 formed on the cylindrical body 20 and the step surface 25, so that the lens 12 is cylindrical. 20 can be fixedly held. At this time, since an external force in a direction orthogonal to the optical axis does not act on the lens 12, the lens 12 is not deformed. For this reason, the lens 12 fixedly held can exhibit a desired optical performance.
[Modification]
FIG. 10A is a diagram showing a modification of the shape of the lens 12, and FIG. 10B is a sectional view taken along line XX. In addition, the same code | symbol is attached | subjected and demonstrated to the member which is the same as that of 1st Embodiment, or corresponds.

  In this embodiment, the lens 12 has three long arc-shaped projections 14 formed on the outer peripheral portion 16. The protrusions 14 are formed at substantially equal intervals of 120 ° along the circumferential direction. Moreover, the hole 18 is formed in the one end side of the circumferential direction of each protrusion 14 at the substantially equal intervals of 120 degrees along the circumferential direction. A recess may be formed in place of the hole 18.

  This hole 18 is used for fitting the three pins 36 of the press-fitting jig 30 and applying a rotational force when the lens 12 is press-fitted into the cylindrical body 20 using the press-fitting jig 30 (see FIG. 7). Is. This modification is the same as the first embodiment except that the protrusions 14 have a long arc shape and the holes 18 are formed in each protrusion 14.

According to this modification, since the protrusion 14 is formed long in the circumferential direction, the degree of freedom of the rotation angle when the lens 12 is press-fitted into the cylindrical body 20 can be increased. That is, when the protrusion 14 of the lens 12 is press-fitted between the pinching piece 28 on the cylindrical body 20 side and the stepped surface 25, the lens 12 does not come off the cylindrical body 20 even if the amount of rotation changes slightly. . Further, when the lens 12 is rotated and press-fitted into the cylindrical body 20, since the hole 18 is formed in the projection 14, the pin 36 of the press-fitting jig 30 is fitted into the hole 18 to securely fix the lens 12. Can be rotated.
[Second Embodiment]
FIG. 11 is a cross-sectional view when the present invention is applied to a lens barrel of an optical apparatus such as a camera or a microscope. In addition, the same code | symbol is attached | subjected and demonstrated to the member which is the same as that of 1st Embodiment, or corresponds.

The lens barrel 40 includes a cylindrical body 20 and a plurality (three) of lenses 12 ₁ , 12 ₂ , 12 ₃ . The cylinder 20 is made of a synthetic resin such as polycarbonate.
An opening 22 is formed in the cylindrical body 20 at the forefront portion on the subject side. Furthermore, like the tubular body 20 shown in FIG. 2, the lens insertion hole _{26 1,} 26 2, 26 _3, the stepped surface _{25 1,} 25 2, 25 _3, clamping flaked _{28 1,} 28 2, 28 ₃ respectively Is formed.

Further, the lenses 12 ₁ , 12 ₂ , and 12 ₃ have protrusions 14 ₁ , 14 ₂ , and 14 ₃ on the outer peripheral portion in the same manner as the lens 12 shown in FIG. These lenses 12 ₁ , 12 ₂ , and 12 ₃ are resin lenses having a glass transition temperature Tg of Tg = 140 ° C.

In the present embodiment, the lens outer diameters of the three lenses 12 ₁ , 12 ₂ , 12 ₃ held in the cylindrical body 20 change in order according to the distance from the subject. That is, the lens outer diameter increases in order as the distance from the subject increases.

Thus, when the lenses 12 ₁ , 12 ₂ , and 12 ₃ are assembled to the cylindrical body 20, the lenses 12 ₁ , the lens 12 ₂ , and the lens 12 ₃ are dropped into the cylindrical body 20 in ascending order of the lens outer diameter. Then, the protrusions 14 ₁ , 14 ₂ , and 14 ₃ of the respective lenses 12 ₁ , 12 ₂ , and 12 ₃ are formed on the stepped surfaces 25 ₁ , 25 ₂ , and 25 ₃ of the cylindrical body 20 and the pinching piece 28 ₁ by the method described above. , 28 ₂ , 28 _3, and press-fit between them.

The lenses 12 ₁ , 12 ₂ , 12 ₃ are fixed to the cylindrical body 20 by pressing the protrusions 14 ₁ , 14 ₂ , 14 ₃ and the outer peripheral portions 16 of the lenses 12 ₁ , 12 ₂ , 12 ₃ (FIG. 3). Reference) is performed in contact with the inner peripheral surfaces of the lens insertion holes 26 ₁ , 26 ₂ , and 26 ₃ .

According to the present embodiment, a plurality of lenses 12 ₁ , 12 ₂ , 12 ₃ can be press-fitted and fixed to one cylindrical body 20. In this case, since the lens _{12 1,} 12 2, 12 ₃ in the radial direction in the outer peripheral portion 16 of the force does not act, the internal stress in the lens _{12 1,} 12 2, 12 ₃ is not generated. In this way, it is possible to fix the lenses 12 ₁ , 12 ₂ , 12 ₃ in the cylindrical body 20 while maintaining desired optical performance.

It is a top view of an optical element assembly. It is sectional drawing which follows the II-II line same as the above. It is a front view of an optical element. It is sectional drawing which follows IV-IV same as the above. It is a V direction arrow directional view of FIG. It is explanatory drawing when the protrusion of an optical element is press-fitted between the pinching piece of a cylindrical body, and a level | step difference surface. FIG. 7A is a front view of a lens press-fitting jig, and FIG. 7B is a side view thereof. It is a figure which shows the stress state added to the optical element in a prior art example. It is a figure which shows the stress state added to the optical element in this embodiment. (A) is a figure which shows the modification of the shape of an optical element, (b) is the XX sectional drawing. It is sectional drawing when this invention is applied to the lens barrel of optical instruments, such as a camera and a microscope.

Explanation of symbols

10 Optical element assembly 12 Lens 12 ₁ , 12 ₂ , 12 ₃ Lens 12a, 12b Optical functional surface 14 Protrusion 14 ₁ , 14 ₂ , 14 ₃ Protrusion 14a Upper surface 14b Lower surface 14c Side surface 14d Side surface 16 Outer peripheral portion 18 Hole 20 Cylindrical body 22 opening 23 stepped surface 24 lens fitting hole 25 stepped surface _{25 1,} 25 2, 25 ₃ step face 26 lens insertion holes _{26 1,} 26 2, 26 ₃ lens insertion hole 28 interposed flaked _{28 1,} 28 2, 28 ₃ nip Pressure piece 28a Lower surface 30 Press-fit jig 32 Main body 34 Holding part 36 Pin 40 Lens barrel

Claims (5)

An optical element assembly in which an optical element is fixedly held in a cylinder,
The optical element has a protrusion protruding in a direction perpendicular to the optical axis on the outer periphery,
The cylindrical body has a clamping portion that sandwiches the projection of the optical element at a predetermined pressure from both sides in the optical axis direction on the inside,
An optical element assembly, wherein the protrusion is press-fitted into the clamping portion and fixedly held. 2. The optical element assembly according to claim 1, wherein at least one of the protrusions is formed into a curved surface among both surfaces in the optical axis direction to be clamped by the clamping unit. 3. The optical element set according to claim 1, wherein the optical element set includes a plurality of optical elements fixedly held in the cylindrical body, and the plurality of optical elements have an outer diameter that is sequentially larger than one direction. Solid. The end surface of the projection in a direction perpendicular to the optical axis is in non-contact with the inner peripheral surface of the cylindrical body in a state where the projection is press-fitted into the pinching portion. The optical element assembly according to any one of the above. The optical element assembly according to claim 1, wherein the cylindrical body is made of resin.