JP2009210693A - Optical element holding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical element holding device that can hold the optical element on a holding member stably regardless of assembly accuracy. <P>SOLUTION: The optical element holding device includes: the annular holding member 1 disposed in contact with the face of the optical element 3 in its peripheral area; an annular spacer disposed in contact with the peripheral area of the optical element and supporting the optical element within the holding member in the direction of its optical axis; and a fixing member 2 having three projections. The three projections press the holding member via the spacer in the direction of the optical axis, thereby holding the optical element. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical element holding device that holds optical elements such as lenses, filters, and prisms, and is suitable for a lens barrel used in an imaging device such as a digital camera or a TV camera.

  2. Description of the Related Art Conventionally, many optical element holding devices that store and hold an optical element in a lens barrel have screws on the outer periphery of a holding member that holds the outer end (peripheral region) of the optical element on a seating surface provided on the entire circumference. It is fixed by an annular fixing member provided. An optical element holding device using such a method is known (see Patent Documents 1 and 2).

  The optical element holding device 38 described in Patent Document 1 is formed in an annular shape that is disposed on the periphery of the optical element 37 and an annular shape that is disposed on the upper surface side of the optical element 37. And a clamping member 42. The frame body 41 has three seats 44 that support the lower surface of the optical element 37. On the other hand, the clamp member 42 has a pressing portion on the lower surface thereof, and the pressing portion and the above-described seat 44 are disposed at the same phase position facing each other through the optical element 37.

Patent Document 2 discloses an exposure that includes a lens having three convex portions arranged on the same circumference at a pitch of 120 degrees and a lens holding member that supports the lens at three points via the three convex portions. An apparatus is disclosed.
JP 2005-266146 A JP 2002-267910 A

  Recently, in the field of broadcasting television lenses, HD has been advanced, and accordingly, higher imaging performance is required for the photographing optical system. Therefore, there is a demand for a more accurate fixing method than conventional optical element fixing methods.

  In Patent Document 1, the positioning accuracy of the clamp member is required, and in addition, when fixing a fixing member having three contact portions with a bolt, it is necessary to manage the tightening torque of the bolt with a good balance. . It is difficult to fix the lens with high accuracy without distortion.

  In Patent Document 2, three convex portions are provided on the optical element and supported by the lens holding member. However, the lens processing for forming the convex portion on the optical element is required, and it tends to be difficult to manufacture the optical element. there were.

  An object of the present invention is to provide an optical element holding device that can stably hold an optical element on a holding member regardless of assembly accuracy.

The optical element holding device of the present invention is
An annular holding member in contact with the surface of the optical element in the peripheral region;
A fixing member having three protrusions,
The three protrusions hold the optical element by pressing the optical element toward the holding member.

In addition, the optical element holding device of the present invention is
An annular holding member in contact with the surface of the optical element in the peripheral region;
An annular spacer that abuts a peripheral region of the optical element and supports the optical element in the optical axis direction in the holding member;
A fixing member having three protrusions,
The three protrusions hold the optical element by pressing the holding member in the optical axis direction via the spacer.

  According to the present invention, an optical element holding device capable of stably holding an optical element on a holding member regardless of assembly accuracy can be obtained.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

  The optical element holding device of the present invention includes an annular holding member that supports various optical elements such as a lens, a filter, and a prism, and an annular fixing member that fixes the optical element to the holding member while rotating. is doing.

  Three optical element contact portions for pressing and fixing the optical element in the optical axis direction are formed uniformly in the circumferential direction in the peripheral region of the fixing member.

  FIG. 1a is a cross-sectional view of Embodiment 1 of the optical element holding device of the present invention used in an imaging apparatus such as a digital camera or a TV camera. FIG. 1b is a schematic view of a part of the fixing member of FIG. 1a.

  In FIGS. 1a and 1b, reference numeral 3 denotes an optical element (lens). Reference numeral 1 denotes a lens barrel that is an annular holding member that supports the optical element 3 in the optical axis direction by contacting the optical element 3 at the periphery thereof. Reference numeral 1 a denotes a seating surface for holding the optical element 3 provided in the lens barrel 1. Reference numeral 1b denotes a female screw (female screw) portion provided on the lens barrel 1 which meshes with a male screw (male screw) portion 2d of a fixing member 2 as a press ring for fixing the optical element 3. Reference numeral 2 denotes a presser ring which is an annular fixing member, and presses the optical element 3 in the optical axis direction. Reference numerals 2a, 2b and 2c denote convex convex portions (protrusions and contact portions) provided in the peripheral region of the press ring 2 in the press direction of the optical element 3, and 120 in the circumferential direction (centered on the optical axis). Evenly arranged at every ° and in contact with the optical element. Reference numeral 2 d denotes a male thread portion provided on the presser ring 2. Reference numeral 2e denotes a rib provided on the presser ring 2, which suppresses deformation of the presser ring 2 (reducing the amount of deformation and improving the bending strength of the presser ring).

  In the above configuration, the lens barrel 1 holds the lens 3 on the entire circumference by the seating surface 1a. The lens 3 is fixed by screwing the male screw portion 2d of the presser ring 2 into the female screw portion 1b of the lens barrel 1, and the lens 3 comes into contact with the convex portions 2a, 2b, 2c of the presser ring 2 and moves in the optical axis direction (pressing direction). ) And is fixed in the holding member. As a result, the lens 3 is pressed at three positions (at intervals of 120 degrees) in the rotation direction by three convex portions arranged at equal intervals (angular intervals) in the rotation direction with respect to the optical axis Oa. Fix it. By fixing (supporting or holding) the lens in this way, astigmatism generated by this lens can be reduced. In particular, as compared with the case where the lens is fixed (supported and held) at two points, distortion caused by the fixation is reduced, and astigmatism caused by the distortion can also be reduced.

  In addition, the rib 2e on the inner peripheral portion of the fixing member 2 makes it difficult to transmit a deformation component due to a twist in the rotational direction that occurs during tightening to the contact portion with the lens 3. This facilitates stable holding.

  FIG. 8a is a schematic diagram showing a deformed shape of the lens 3 when the lens 3 is held by the optical element holding device of the present embodiment.

  In FIG. 8 a, 3 a, 3 b, 3 c are contact points where the fixing member 2 contacts the lens 3. These three contact points come into contact with the lens 3 at three positions around the periphery of the lens 3 (three equal positions in the circumferential direction around the optical axis of the lens), thereby reducing the amount of astigmatism generated. Reduced.

  FIG. 8b is a diagram showing the deformation state of the lens 3 of FIG. 8a by interference fringes corresponding to the lens surface 3d. As can be seen from FIG. 8 b, it can be seen that the generated astigmatism is small with respect to the light beam passing through the lens 3.

  2a and 2b are cross-sectional views of the optical element holding device when the contact portion of the fixing member of Example 1 with the optical element is expressed in another form (when viewed from the direction of the optical axis 0a) and the fixing member It is explanatory drawing.

  2A and 2B, the same members as those in FIGS. 1A and 1B are denoted by the same reference numerals. The same applies to the following embodiments.

  2a and 2b, 11 is a presser ring which is a fixing member. Reference numerals 11a, 11b, and 11c are convex portions (projections) that are provided on the presser ring 11 and project in the optical axis direction, and are uniformly arranged at intervals of 120 ° in the circumferential direction around the optical axis Oa. 11 d is a male thread portion provided on the presser ring 11. Reference numeral 1 denotes a lens barrel, and 3 denotes a lens, which is the same as in FIGS. 1a and 1b.

  In the above configuration, the lens barrel 1 holds the lens 3 on the entire circumference by the seating surface 1a. The lens 3 is fixed by screwing the male screw portion 11 d of the presser ring 11 into the female screw portion 1 b of the lens barrel 1. The lens 3 comes into contact with the convex portions 11a, 11b, and 11c of the presser ring 11 (arranged at intervals of 120 degrees in the circumferential direction around the optical axis) and is pressed in the optical axis direction. Thereby, it is possible to hold the lens 3 so that the influence on the astigmatism is small.

  In addition, you may provide the contact seal (a contact seal is stuck on the surface which faced the optical axis direction) mentioned later instead of the convex part as a contact part with the optical element of a presser ring. The same applies to each embodiment described later that does not use a contact seal.

  FIG. 3A is a cross-sectional view of Embodiment 2 of the optical element holding device of the present invention. FIG. 3b is an explanatory view of a part of the fixing member of FIG. 3a.

  3a and 3b, 4 is a presser ring which is a fixing member. 4a is a male thread portion provided on the presser ring 4, and 4b is a rib provided on the presser ring 4, which suppresses deformation of the presser ring 4. Reference numeral 5 denotes an annular spacer that connects the optical element 3 and the presser ring 4. 5a, 5b, and 5c are convex convex portions that are optical element contact portions provided in the peripheral region of the spacer 5, and are uniformly arranged at intervals of 120 ° in the circumferential direction. Reference numeral 1 denotes a lens barrel, and reference numeral 3 denotes a lens (optical element), which is the same as in FIGS. 1a and 1b.

  The presser ring 4 in this embodiment has a simple annular shape, and there is no optical element contact portion in the peripheral region.

  In the above configuration, the lens barrel 1 holds the lens 3 on the entire circumference by the seating surface 1a. By screwing the male screw portion 4a of the presser ring 4 into the female screw portion 1b of the lens barrel 1, the lens 3 is fixed via the spacer 5, and is pressed by contact with the convex portions 5a, 5b, 5c of the spacer 5. Thereby, the lens 3 is pressed in three places. Further, the rib 4b on the inner peripheral portion of the presser ring 4 makes it difficult to transmit a deformation component due to a twist in the rotational direction that occurs during tightening to the contact portion with the lens 3, thereby enabling stable holding. . With such a configuration, the same effect as in the first embodiment is obtained.

  4A and 4B are a cross-sectional view of the optical element holding device and an explanatory view of the spacer when the optical element contact portion of the spacer according to the second embodiment is expressed in another form.

  In FIGS. 4 a and 4 b, reference numeral 12 denotes an annular spacer that connects the optical element 3 and the presser ring 4. Reference numerals 12a, 12b, and 12c are convex portions that are optical element contact portions provided on the spacer 12 and protrude in the central direction of the optical axis Oa, and are uniformly arranged at intervals of 120 ° in the circumferential direction. Reference numeral 1 denotes a lens barrel, 3 denotes a lens, and 4 denotes a presser ring, which is similar to FIGS. 3a and 3b.

  In the above configuration, the lens barrel 1 holds the lens 3 on the entire circumference by the seating surface 1a. By screwing the male screw portion 4a of the presser ring 4 into the female screw portion 1b of the lens barrel 1, the lens 3 is fixed via the spacer 12, and is contacted by the convex portions 12a, 12b, and 12c of the spacer 12 and pressed in the optical axis direction. Is done. Thereby, the lens 3 is pressed in three places. In addition, the rib 4b on the inner peripheral portion of the presser ring 4 makes it difficult to transmit a deformation component due to a twist in the rotational direction that occurs during tightening to the contact portion with the lens 3. This facilitates stable holding. With such a configuration, the same effect as in the first embodiment is obtained.

  5a and 5b are a cross-sectional view of the optical element holding device and an explanatory diagram of the spacer when the optical element contact portion of the spacer of Example 2 is represented in another form.

  In FIGS. 5 a and 5 b, reference numeral 13 denotes a spacer that connects the optical element 3 and the presser ring 4. 13a, 13b, and 13c are convex portions that are optical element contact portions provided on the spacer 13, and are evenly arranged at intervals of 120 ° in the circumferential direction. 13d, 13e, and 13f are convex portions that are fixing member contact portions provided on the opposite side of the convex portions 13a, 13b, and 13c provided on the spacer 13 at the same phase as the convex portions 13a, 13b, and 13c. They are evenly arranged at intervals of 120 ° in the circumferential direction.

  That is, the convex portions 13d to 13f are opposed to the convex portions 13a to 13c. Reference numeral 1 denotes a lens barrel, 3 denotes a lens, and 4 denotes a presser ring, which is similar to FIGS. 3a and 3b.

  In the above configuration, the lens barrel 1 holds the lens 3 on the entire circumference by the seating surface 1a. By screwing the male screw portion 4a of the presser ring 4 into the female screw portion 1b of the lens barrel 1, the lens 3 is fixed via the spacer 13, and contacts with the convex portions 13a, 13b, and 13c of the spacer 13. The presser ring 4 comes into contact with the convex portions 13d, 13e, and 13f of the spacer 13 and is pressed in the optical axis direction. Thereby, the lens 3 is pressed in three places. In addition, the rib 4b on the inner peripheral portion of the presser ring 4 makes it difficult to transmit a deformation component due to a twist in the rotational direction that occurs during tightening to the contact portion with the lens 3. This facilitates stable holding. With such a configuration, the same effect as in the first embodiment is obtained.

  6a, 6b, and 6c are a cross-sectional view, an explanatory view of a spacer, and an explanatory view of a holding member (lens barrel) of Example 3 of the optical element holding device of the present invention in order.

  6a, 6b, and 6c, 6 is a lens barrel that is a holding member. 6a, 6b, and 6c are convex convex portions that hold the optical element 3 provided in the lens barrel 6, and are uniformly arranged at intervals of 120 ° in the circumferential direction. Reference numeral 6 d denotes a female screw provided in the lens barrel 6. A spacer 7 connects the optical element 3 and the fixing member 4. Reference numerals 7a, 7b, and 7c are convex portions that are optical element contact portions provided on the spacer 7, and are uniformly arranged at intervals of 120 ° in the circumferential direction. Reference numeral 8 denotes a positioning pin for aligning the phases of the convex portions 6a, 6b, 6c of the lens barrel 6 and the convex portions 7a, 7b, 7c of the spacer 7. The positioning pin 8 is engaged with the hole of the spacer 7 so that the spacer 7 can move in the optical axis direction. Reference numeral 3 denotes a lens, and reference numeral 4 denotes a presser ring, which is similar to FIGS. 3a and 3b. 4a is a male thread portion of the presser ring 4, 4b is a rib provided on the presser ring 4, and is the same as shown in FIGS. 3a and 3b.

  In the above configuration, the lens barrel 6 holds the lens 3 at three positions by the convex portions 6a, 6b, and 6c. By screwing the male threaded portion 4a of the presser ring (fixing member) 4 into the female threaded portion 6d of the lens barrel 6, the lens 3 is fixed via the spacer 7 and is contacted by the convex portions 7a, 7b, 7c of the spacer 7, and light It is pressed in the axial direction. At this time, since the convex portions 6a, 6b, 6c of the lens barrel 6 and the convex portions 7a, 7b, 7c of the spacer 7 are arranged in the same phase in the circumferential direction by the positioning pins 8, the lens 3 is arranged in the peripheral region. It is pressed at 3 places from both sides. Further, the rib 4b on the inner peripheral portion of the presser ring 4 makes it difficult to transmit a deformation component due to a twist in the rotational direction that occurs during tightening to the contact portion with the lens 3, and enables more stable holding. Thereby, the effect similar to Example 1 is acquired.

  7a and 7b are a cross-sectional view of an optical element holding apparatus according to a fourth embodiment of the present invention and an explanatory view of a fixing member.

  7a and 7b, reference numeral 14 denotes a presser ring which is a fixing member. Reference numeral 14 a denotes a male thread portion provided on the presser ring 14. Reference numeral 14b denotes a rib provided on the presser ring 14, which suppresses deformation of the presser ring 14.

  Reference numeral 15 denotes an optical element contact portion formed on the presser ring 14 that comes into contact with the peripheral region of the optical element 3. The optical element contact portion 15 is a contact seal made of resin or metal, and is bonded evenly at 120 ° intervals in the circumferential direction on the fixing surface side of the optical element 3 of the presser ring 14.

  The contact seal is made of the same material as the presser ring 14 or a different material.

  Reference numeral 1 denotes a lens barrel, and 3 denotes a lens, which is the same as shown in FIGS. 1a and 1b.

  In the above configuration, the lens barrel 1 holds the lens 3 on the entire circumference by the seating surface 1a. The lens 3 is fixed by screwing the male screw portion 14 a of the presser ring 14 into the female screw portion 1 b of the lens barrel 1. The lens 3 is contacted by a contact seal 15 bonded to the presser ring 14 and pressed in the optical axis direction. Further, the rib 14b on the inner peripheral portion of the presser ring 14 makes it difficult to transmit a deformation component due to a twist in the rotational direction that occurs during tightening to the contact portion with the lens 3, and enables more stable holding. Thereby, the effect similar to Example 1 is acquired.

  As described above, in each embodiment, the optical element held by the holding member that supports the optical element in the optical axis direction is fixed by the fixing member having an annular structure having three optical element contact portions. As a result, it is possible to minimize the occurrence of astigmatism in the passing light beam with a simple structure without requiring high assembly accuracy that occurs when the three fixing members are equally arranged in the circumferential direction.

  Alternatively, it is fixed by a fixing member through a spacer having a ring shape and three optical element contact portions formed in the peripheral region. Thereby, the same effect is obtained.

  For this reason, in each Example, the adjustment work for reducing astigmatism becomes unnecessary, and manufacture becomes easy. In addition, by reducing astigmatism, an imaging device such as a digital camera or a TV camera having high optical performance can be easily obtained.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist. For example, the convex portion as the optical element contact portion may be replaced with a contact seal in each embodiment.

Sectional drawing of the optical element holding | maintenance apparatus which concerns on Example 1 of this invention. Detailed view of the fixing member of FIG. Sectional drawing of a partial deformation | transformation of the optical element holding | maintenance apparatus of Example 1. FIG. Detailed view of the fixing member of FIG. 2a Sectional drawing of the optical element holding | maintenance apparatus which concerns on Example 2 of this invention. Detailed view of the spacer of FIG. 3a Sectional drawing of the partial deformation | transformation of the optical element holding | maintenance apparatus of Example 2. FIG. Detailed view of the spacer of FIG. 4a Sectional drawing of the partial deformation | transformation of the optical element holding | maintenance apparatus of Example 2. FIG. Detailed view of the spacer of FIG. 5a Sectional drawing of the optical element holding | maintenance apparatus which concerns on Example 3 of this invention. Detailed view of the contact portion of the spacer of FIG. 6a Detailed view of the holding member of FIG. Sectional drawing of the optical element holding | maintenance apparatus which concerns on Example 4 of this invention. Detailed view of the fixing member of FIG. The perspective view showing the deformation | transformation state of the optical element in this invention Interference fringes in the deformed state of the optical element in FIG. 8a

Explanation of symbols

1, 6: Lens tube (holding member)
2, 4, 11, 16, 14: Presser ring (fixing member)
3.9: Lens (optical element)
5, 7, 12, 13: Spacer 8: Positioning pin 15: Contact seal 10: Tool
0a: Optical axis
1a, 6a: Bearing surface
1b, 6d: Female thread
2d, 4a, 11d, 14a: Male thread
2a, 2b, 2c, 5a, 5b, 5c, 6a, 6b, 6c, 7a, 7b, 7c, 11a, 11b, 11c: Convex part (optical element contact part)
2e, 4b, 14b: Ribs
3a, 3b, 3c, 9a, 9b, 16c, 16d: Contact point
10a, 10b: Pin part
12a, 12b, 12c, 13a, 13b, 13c, 13d, 13e, 13f: Convex part (optical element contact part)
16a, 16b: Hole

Claims (7)

An annular holding member in contact with the surface of the optical element in the peripheral region;
A fixing member having three protrusions,
The optical element holding device, wherein the three protrusions hold the optical element by pressing the optical element toward the holding member. An annular holding member in contact with the surface of the optical element in the peripheral region;
An annular spacer that abuts a peripheral region of the optical element and supports the optical element in the optical axis direction in the holding member;
A fixing member having three protrusions,
The optical element holding device, wherein the three protrusions hold the optical element by pressing the holding member in the optical axis direction via the spacer.   A fixing member contact portion is formed at a position in the same phase as that of the three protrusions on a surface of the peripheral region of the spacer opposite to the surface on which the three protrusions are provided. The optical element holding device according to claim 2, wherein:   The optical element holding device according to claim 1, wherein the three protrusions are formed uniformly in a circumferential direction of the optical axis.   5. The optical element holding device according to claim 1, wherein the three protrusions are protrusions protruding in the optical axis direction. 6.   5. The optical element holding device according to claim 1, wherein the three protrusions are protrusions protruding in a circumferential direction around the optical axis. 6.   An imaging apparatus comprising the optical element holding device according to claim 1.