JP2001013390A - Lens frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens which can be positioned in a state where optical performance is hardly lowered even when the lens is shifted because fitting looseness exists between the lens and a lens frame. SOLUTION: This lens frame 11 is a lens supporting frame whose surface receiving the lens 1 is formed to be spherical in order to support and hold the lens 1 inside. When the lens frame 11 supports the lens 1 having two spherical surfaces 1a and 1c to be opposed, the center of the spherical surface 11b formed on the lens frame 11 is provided at the same place as the center of either spherical surface 1c of the lens 1, that is, the center O1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element,
More specifically, the present invention relates to a lens frame for holding a lens.

[0002]

2. Description of the Related Art Generally, when a plurality of lenses are arranged in a cylindrical lens barrel using a lens frame, the performance of an optical system is determined by not only the center accuracy of the lens frame in the design and the center accuracy of the lens but also each lens. When it is fixed in a frame, it is greatly affected by positioning accuracy such that its center is aligned on the optical axis. As a technique relating to an optical lens proposed in recent years, for example, Japanese Unexamined Patent Publication No.
According to the method of assembling a lens system taught in Japanese Patent Application Laid-Open No. 8710, a method has been proposed in which a lens is aligned on an optical axis by a “bell chuck method” and is enclosed in a resin and mounted in a lens barrel.

[0003] Further, a technique using a lens surface shape device and a frame material contacting the lens surface is disclosed in, for example, Japanese Patent Application Laid-Open No.
There is a lens holding mechanism as taught in Japanese Patent Application Laid-Open No. 8-158615, and this mechanism is a holding technique used to reduce the occurrence of lens aberration tilted with respect to the optical axis. It can be seen that such prior art has been addressed by improving the lens itself or the frame of the lens barrel for correct positioning of the lens.

[0004]

With the above-described improved technique, the "centering" step of the lens is unnecessary or simplified, and the assembly and the optical performance can be improved to some extent.
However, even in the assembling method disclosed in JP-A-59-68710, when the lens is correctly positioned on the lens frame, for example, the positioning is performed while supporting the lens on a predetermined spherical surface based on the conventional bell chuck method. Since the displacement is within a range of a predetermined play (fitting play) provided in the inner diameter of the lens frame, a shift of the center from the optical axis due to a mismatch between the lens frame and the lens surface is caused at this time. This has a significant effect on the performance degradation.

Also, in the lens holding mechanism disclosed in Japanese Patent Application Laid-Open No. 58-158615, so-called "parallel eccentricity" occurs in a direction perpendicular to the optical axis, and the eccentricity of the lens causes deterioration of the performance of the optical system. . As described above, conventionally, techniques for maintaining the initial alignment and the accuracy of its design,
No technique is taught for enabling easy positioning.

[0006] A normal optical lens has many of its major surfaces supported by a lens barrel with a spherical surface, but is supported by a part of the optical characteristic surface of the lens having a plurality of spherical surfaces (for example, an end surface near the lens periphery). In order to increase the mounting accuracy of the main optical characteristic surface (first spherical surface) that is important for performance, even if the position on the supported surface (support point) is slightly displaced within that surface, It is necessary to devise a method so that one spherical surface does not substantially deviate from the optical axis.

Accordingly, an object of the present invention is to provide a lens barrel which can be positioned with little reduction in optical performance even if the lens shifts within a certain range of the play between the lens and the barrel. Is to do.

[0008]

Means for Solving the Problems In order to solve the above problems and achieve the object, the present invention takes the following measures. According to the present invention, for example, when a lens is supported by the inside of a mirror frame formed of a spherical surface, the mounting accuracy of a main optical characteristic surface (first spherical surface or second spherical surface) of the lens is improved.
This defines the shape of a lens frame having the same center on the optical axis as the center of the first and second spherical surfaces, which can be supported so-called "coaxially".

That is, according to a first aspect of the present invention, there is provided a lens barrel characterized in that a surface for receiving and supporting the lens is a spherical surface for supporting and holding the lens. According to the second invention, there is proposed a lens barrel having a spherical shape for receiving one of the spherical surfaces of a lens having two spherical surfaces opposed to each other, and having a frame member for supporting and holding this lens. .

According to the third aspect, in order to support a circular lens having two spherical surfaces opposed to each other, the center of the spherical surface of the other spherical surface of the lens is received by receiving one of the spherical surfaces of the lens. A lens frame including an annular frame member having a lens receiving surface with a spherical surface centered on the center is proposed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The gist of the present invention will be described below in detail with reference to a plurality of embodiments. (First Embodiment) FIG. 1 illustrates a lens barrel 11 for holding a lens 1 according to a first embodiment of the present invention. A set of optical elements composed of a lens frame (hereinafter abbreviated as “mirror frame” or simply “frame”) 11 and lens 1
They are assembled and assembled so as to have "coaxiality" which passes through the center of one opening and has the same optical axis. That is, according to the sectional view at the time of assembly shown in FIG. 1, it can be seen that the lens 1 is in contact with and supported by the inner surface of the lens frame 11 and is fixed.

The frame 11 of the first embodiment has two optical characteristic surfaces (a surface having a predetermined radius: a first optical characteristic surface 1a and a surface having a predetermined radius: a second optical characteristic surface 1c). The lens 1 is attached such that a portion exposed to the opening has an effective diameter of the lens 1. In a set of optical elements composed of the lens 1 and the frame 11, the lens surfaces are arranged with a predetermined curvature and an effective diameter so as to face each other as two main optical characteristic surfaces. Is constituted by, for example, a spherical surface, and the center of the spherical surface is located at O1 on the optical axis.
The other surface provided opposite to the second optical characteristic surface 1c
The (first optical characteristic surface 1a) is also, for example, a spherical surface in this example, and has a large curvature such that the center thereof is not shown.

The spherical end 1b at the peripheral end of the first optical characteristic surface 1a forms a concave surface having a "ring shape" having a center coincident with the center of the spherical surface of one of the second optical characteristic surfaces 1c. It is in contact with the inner surface (support portion) 11b of the frame. However, the actual shape of the support portion 11b may not be a continuous concave surface, and although not shown, for example, a plurality of portions of this ring-shaped surface, that is, at equal intervals (for example, 12
The lens 1 may be formed so as to support the lens 1 at a plurality of locations (three locations) divided at every 0 °.

The curvature will be described in more detail.
1 has a center O on the optical axis.
1 is a concave spherical surface (surface of radius R1) having a radius R1 having 1. The concave lens surface (surface of radius R2: second optical characteristic surface) 1c having the same center O1 and radius R2 is designed to face the above-mentioned first optical characteristic surface 1a.
In other words, when the spherical end portion 1b of the lens 1 is brought into contact with the frame 11 with its corner (1b) being in contact with the inner surface 11b of the frame 11 in the frame 11, the lens 1 and the frame 11 are designed. Are designed to be substantially coaxially aligned.

An appropriate minute gap required for assembly is provided between the outer diameter portion of the lens 1 and the inner peripheral surface 11a of the frame.
Therefore, the position of the lens 1 is determined with variation within the range of the gap. However, at this time, if fine adjustment for more accurate alignment is necessary, the position may be slightly shifted while the spherical end portion 1b of the lens 1 is in contact with the inner surface 11b of the frame 11 that is a concave surface of the frame 11. it can. Lens 1
After the predetermined alignment is obtained by fine adjustment such as aligning the frame 11 and the frame 11 coaxially, an adhesive is injected into a gap between the inner peripheral surface 11a of the frame and the peripheral edge of the lens 1 to be integrally fixed. Become.

A frame 11 having a characteristic sectional shape as shown in FIG. 1 has an appearance as shown in FIG. 2, and when the lens 1 is mounted from the opening in the direction of the thick arrow, this lens 11 1 of the frame 1 passes through the inner peripheral surface 11a of the frame.
When the lens abuts on the inner surface 11b of the concave frame formed in the lens 1, the support point in contact with the lens 1 forms a ring shape continuously. As described above, when the lens 1 is received on the inner surface 11b of the frame, fine adjustment for aligning the axis with the optical axis of the optical system is performed when necessary, and the lens frame 11 is assembled. The lens 1 is integrated with the lens 1 as a frame for holding and fixing the lens 1 in a correct position.

(Function and Effect 1) According to the first embodiment, since the lens 1 is supported and held inside,
The frame 11 serving as a lens support frame is characterized in that the surface (frame inner surface 11b) receiving the light has a concave shape, for example. At this time, particularly, the frame 11 has two spherical surfaces 1a and 1c.
, Ie, one spherical surface 1a is a first optical characteristic surface protruding toward the frame inner surface 11b side, and the other spherical surface 1c is a second optical characteristic surface recessed toward the frame inner surface 11b side. Lens 1 is supported. In this case, the center of the spherical surface of the inner surface 11b of the frame 11 is designed to be at the same center O1 on the optical axis as the center of the spherical surface 1c as the second optical characteristic surface of the lens 1. Therefore, even if the lens 1 slightly moves in a state where the lens 1 is applied, the corner (spherical end 1b) is displaced only along the inner surface 11b of the frame that supports the corner.

That is, the spherical end 1b including the point to be supported
Is displaced about the same spherical center O1 as the spherical surface 1c as the second optical characteristic surface of the lens 1, so that at least the spherical surface 1c as the main second optical characteristic surface has its spherical center when following the displacement. O1 does not deviate from the optical axis, and substantially coaxiality can be maintained.

As described above, by designing the lens frame 11 to have a characteristic shape, when a fine adjustment is required for positioning during assembly, the "fitting play" between the lens 1 and the lens frame 11 provided in advance is required. Within the range of “amount”, even if the lens 1 to be mounted is slightly shifted from a predetermined design support point due to positioning or the like, it is possible to extremely reduce deterioration of optical performance. The movable range of the supported lens 1 is a frame inner surface 1 which is a ring-shaped concave surface provided on the inner surface of the lens frame 11.
1b, which is outside the lens aperture (effective diameter).

As described above, the center of the concave surface forming the inner surface 11b of the lens frame 11 according to the first embodiment substantially exists at the same position on the optical axis as the center O1 of the facing lens spherical surface 1c. According to the design that satisfies the geometrical conditions, the thrust position (that is, the position in the optical axis direction) generated when fine adjustment for positioning is possible in a structure having an initial play amount
, There is no eccentric component from the optical axis, so that the positioning does not adversely affect the accuracy of the optical system.

The method for manufacturing the lens frame 11 having the above-described shape is not the gist of the present invention, and thus a detailed description thereof is omitted. In the molding process.

Therefore, the symmetry of the frame 11 based on the design,
As long as the coaxiality is maintained within an allowable range by manufacturing, at least the main optical characteristic surface of the lens 1 and the lens frame 1 will be maintained even if some deviation occurs in the adjustment process in the positioning process of the lens 1.
Since the coaxiality with the inner surface 11b of the frame 1 is maintained, the basic optical characteristics are hardly affected.

(Second Embodiment) The lens frame illustrated below is an example in which a lens to be mounted has a shape characteristic corresponding to the shape different from that of the first embodiment. FIG. 3 shows a lens barrel (hereinafter simply referred to as “frame”) 12 as a second embodiment of the present invention, and the frame 12.
FIG. 2 is a sectional view showing a state in which the lens 2 supported by the lens 2 is integrated. FIG. 4 shows the appearance when the lens 2 is to be incorporated into the frame 12.

Frame 12 and lens 2 according to the second embodiment
Are assembled with the same optical axis passing through the center of the opening of the frame, and the lens 1 is brought into contact with the inner surface of the frame 12 and supported by the assembly as shown in FIG. Fixed. At this time, the lens 2 having the first optical characteristic surface 2a and the second optical characteristic surface 2c each having a predetermined radius is designed such that the portion exposed to the opening becomes the effective diameter of the lens. On the optical axis based on

In a set of optical elements composed of the lens 2 and the frame 12, these lens surfaces are arranged with a predetermined effective diameter so as to face each other as main optical characteristic surfaces. At least one of the surfaces (the second optical characteristic surface 2c) is, for example, a spherical surface, and the center of the spherical surface is located at O1 on the optical axis. The other surface (first optical characteristic surface 2a) opposite to the second optical characteristic surface 2c is a concave spherical surface as shown in the drawing, which is different from the first embodiment.

The spherical end 2b at the peripheral end of the first optical characteristic surface 2a has an inner surface (a ring-shaped convex surface having a center coincident with the center of the spherical surface of the second optical characteristic surface 2c). Support portion) 12b. The shape of the actual support portion 12b may not be a continuous convex surface, and may be a lens (not shown), for example, a ring-shaped surface portion, that is, a lens at a plurality of portions (three portions) divided at equal intervals (eg, every 120 °). 2 may be formed so as to support them.

To describe the curvature in detail, the frame inner surface 12b provided inside the frame 12 is a concave spherical surface having a center R1 on the optical axis and having a radius R1 (a surface having a radius R1). The convex lens surface (surface of radius R2: second optical characteristic surface) 2c having the same center O1 and radius R2 is designed to face the above-mentioned first optical characteristic surface 2a. Also,
When the corner (2b) of the spherical end portion 2b of the lens 2 abuts on the inner surface 12b of the frame 12 and is integrally applied to the frame 12, the pair of lenses 2 and the frame 1
2 are designed to be substantially coaxially aligned.

However, if fine adjustment for more accurate alignment is required, the position is slightly shifted while the spherical end 2b of the lens 2 is in contact with the inner surface 12b of the frame 12 which is a convex surface of the frame 12. be able to. Then, the lens 2 and the frame 12
When the alignment is obtained by fine adjustment such as coaxial adjustment, the adhesive is injected into the gap between the inner peripheral surface 12a of the frame and the peripheral edge of the lens 2 to perform integral fixing.

The frame 12 having the characteristic sectional shape as shown in FIG. 3 has the appearance as shown in FIG. 4, and when the lens 2 is mounted from the opening in the direction of the thick arrow, first, the lens 2 Of the spherical inner surface 1a passing through the wide inner peripheral surface 12a of the frame and forming a convex spherical surface formed in the frame 12.
When the contact point 2b contacts the lens 2, the support point in contact with the lens 2 forms a continuous ring. In this way, when the lens 2 is received on the inner surface 12b of the frame, the frame 2 is assembled by performing fine adjustment to match the axis on the optical axis of the optical system when necessary, and the frame 12 holds the lens 2. Then, it is integrated with the lens 2 as a frame to be fixed.

(Function and Effect 2) As described above, according to the second embodiment, in order to support and hold the lens 2 inside, the surface receiving the lens 2, that is, the inner surface 12b of the frame has, for example, a convex shape. Thus, a mirror frame as a lens support frame is realized. At this time, in particular, the first spherical surface 2a of the lens 2 having the two spherical surfaces 2a and 2c facing each other is the first optical characteristic surface concave toward the frame inner surface 12b, and the second spherical surface 2c is positioned on the frame inner surface 12b. When supporting the lens 2 having a shape that is a protruding second optical characteristic surface, the center of the spherical surface of the frame inner surface 12b that forms the spherical surface formed on the frame 12 is the second optical characteristic surface of the lens 2 to be mounted. Spherical surface 2c as
Is designed to be located at the same center O1 on the optical axis as the center of the spherical surface of the lens 2, so that even if the lens 2 is slightly moved in contact with the inner surface 12b of the frame, the corner (spherical end) of the lens 2 2b
Will be displaced only in the range along the frame inner surface 12b that supports it.

That is, the spherical end 2b including the point to be supported
Are displaced about the same spherical center O1 as the spherical surface 2c as the second optical characteristic surface of the lens 2, so that at least the spherical surface 2c as the main second optical characteristic surface is moved to the center of the spherical surface when following the displacement. O1 is not shifted from the optical axis, and coaxiality can be maintained.

As described above, also in the second embodiment, since the lens 2 is designed to have a characteristic shape in accordance with the surface of the lens 2 to be attached, even if fine adjustment is required for positioning during assembly, it is provided in advance. If the lens 2 is within the range of “fitting play” between the lens and the lens frame, even if the lens 2 is shifted from a predetermined design support point, the reduction in optical performance due to positioning can be reduced. Becomes

Further, according to the design which satisfies the geometrical condition that the center of the convex surface forming the frame inner surface 12b of the frame 12 substantially exists at the same position on the optical axis as the center O1 of the facing lens spherical surface 2c. Even if there is a displacement of the thrust position (position in the optical axis direction) that occurs when fine adjustment for positioning or the like is possible in a structure with a play, there is no eccentric component from the optical axis. Does not adversely affect the accuracy of the optical system. Therefore, if the symmetry of the frame based on the design and the coaxiality are kept within the allowable range by manufacturing, even if some deviation occurs in the adjustment in the lens positioning process, at least the main optical characteristic surface of the lens Since the coaxiality of the lens frame with the inner surface of the lens frame is maintained, the basic optical characteristics are hardly affected. That is, also in the second embodiment, the operation and effect substantially the same as the operation and effect 1 described above can be obtained.

(Modification) The first embodiment described above may be modified as follows. That is, the lens 1 (see FIG. 1) mounted on the lens barrel of the first embodiment described above is
The first optical characteristic surface 1a that is in contact with the lens is convex, but this characteristic surface may be concave, and even such a lens frame can be matched with the lens almost as it is. Further, for example, the shape of the details of the lens 1 may be appropriately changed depending on the optical device to be used, the combination of the optical elements, or the manufacturing method.

The above description has been made on the assumption that the lens support surface (frame inner surface) provided on the lens frame is a “spherical surface”. An approximate spherical surface having a predetermined shift,
The gist of the present invention can be similarly applied to a so-called “approximate spherical surface”. Usually, these are point-symmetric with respect to the optical axis regardless of whether they are spherical or aspherical. Basically, this aspherical or approximate spherical surface is a formula including the difference from the radius of a predetermined spherical surface and the displacement from the center of the spherical surface. It can be treated almost the same except for the design differences. In this case, effects equivalent to or higher than those of the above embodiments can be expected.

(Other Modifications) In addition, various modifications can be made without departing from the gist of the present invention.

Although the description has been given based on the plural embodiments and the modifications thereof, the present invention includes the following invention. (1) A lens supporting frame (mirror frame / holding frame) characterized in that a lens receiving surface for receiving the lens for supporting the lens is formed of a spherical surface.

(2) The lens support frame according to (1), wherein the lens support frame is formed in an annular shape. (3) The lens support frame according to (1), wherein the lens receiving surface is formed in an annular shape. (4) The lens support frame according to (1), wherein the lens receiving surface is formed as a convex spherical surface. (5) The lens support frame according to (1), wherein the lens receiving surface is formed as a concave spherical surface.

(6) A lens frame for supporting a lens having two spherical surfaces opposed to each other, having a spherical shape for receiving one of the spherical surfaces of the lens, and including a frame member for supporting the lens. A lens barrel characterized by the fact that:

(7) A lens frame for supporting a circular lens having two surfaces opposed to each other. The lens frame receives one of the surfaces of the lens to support the lens, and receives the other of the surfaces of the lens. It is possible to provide a lens barrel having an annular frame member having a lens surface having a shape centered on the center of the surface.

(8) In a lens barrel supporting a circular lens having two spherical surfaces opposed to each other, one of the spherical surfaces of the lens is received to support and fix the lens, and the other of the spherical surfaces is received. And a lens frame provided with an annular frame member having a spherical surface centered on the center of the spherical surface as a lens receiver.

(9) The curvature of the spherical surface is larger in the curved surface of the lens when the non-contacting main spherical surface of the two spherical surfaces of the lens is convex, while the curvature of the main spherical surface is concave. In some cases, the lens barrel according to (8), wherein the curved surface of the lens barrel has a larger curvature.

(10) In a lens frame for supporting a lens having a first optical characteristic surface and a second optical characteristic surface facing each other, the lens surface of the first optical characteristic surface or the second optical characteristic surface A lens frame, wherein a surface having the same center as the center is formed, and the surface has a ring-shaped surface for receiving and supporting the lens.

(11) The lens support frame according to (10), wherein the ring-shaped surface supporting the lens is a convex surface formed inside the lens frame. (12) The ring-shaped surface supporting the lens is a concave surface formed inside the lens barrel (1).
It is a lens support frame of 0).

(13) A lens support frame (mirror frame) characterized in that the surface for receiving the lens for supporting the lens is composed of an "aspheric surface" or an "approximate spherical surface".

(14) A lens frame for supporting and fixing a lens having two surfaces of "aspheric surface" or "approximate spherical surface" facing each other, and having the same curvature for receiving one surface of the lens. A lens barrel having an aspherical or approximate spherical shape and including a frame member that supports the lens can be provided.

(15) A lens frame for supporting and fixing a circular lens having two spherical surfaces opposed to each other. The lens frame receives one of an aspherical surface and an approximate spherical surface of the lens to support the lens. A lens barrel can be provided, comprising an annular frame member having an aspherical or approximate spherical surface centered on the surface center of the other surface of the lens as a lens receiver.

(16) The aspheric or approximate spherical surface is
(15) The lens barrel according to (15), wherein the center of the ring-shaped surface and the center of the other surface of the lens surface that abuts the surface are formed to coincide on the optical axis. It is.

(17) When one lens surface of a lens having two main optical characteristic surfaces is supported by a lens frame having a surface centered on a point on the same optical axis as the center of the lens surface, A lens frame can be provided in which the surface of the lens frame contacts a part of the lens surface to support the lens.

[0050]

As described above, according to the present invention, even if the supporting lens shifts due to the backlash between the lens and the lens frame, the optical performance is reduced little and positioning is possible. A lens barrel can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state in which a lens barrel as a first embodiment of the present invention holds a lens therein.

FIG. 2 is a perspective view showing the lens barrel of the first embodiment illustrated in FIG. 1 and a lens to be held by the lens barrel;

FIG. 3 is a sectional view showing a state in which a lens barrel as a second embodiment of the present invention holds a lens therein.

FIG. 4 is a perspective view showing a lens barrel of the second embodiment illustrated in FIG. 3 and a lens to be held by the lens barrel;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Lens, 1a ... Spherical surface (R1 surface: 1st optical characteristic surface), 1b ... Spherical end part (supported part), 1c ... Spherical surface (R2 surface: 2nd optical characteristic surface), 2 ... Lens, 2a ... spherical surface (R1 surface: first optical characteristic surface), 2b: spherical end (supported portion), 2c: spherical surface (R2 surface: second optical characteristic surface), 11: frame (lens frame of the first embodiment) ), 11a: inner peripheral surface of the frame, 11b: inner surface of the frame (concave surface: abutting portion including the lens support point), 12: ... frame (lens frame of the second embodiment), 12a: inner peripheral surface of the frame, 12b ... inner surface of the frame (convex surface: contact portion including lens support point).

Claims (3)

[Claims] 1. A lens barrel, wherein the surface for receiving and supporting the lens comprises a spherical surface. 2. A lens frame for supporting and holding a lens, comprising a frame member having a spherical shape for receiving one of the spherical surfaces of the lens having two spherical surfaces opposed to each other and supporting the lens. A lens frame. 3. A lens barrel for supporting and holding a lens, wherein for supporting the circular lens having two spherical surfaces opposed to each other, receiving one of the spherical surfaces of the lens and the other of the spherical surfaces of the lens. A lens frame comprising an annular frame member having a spherical surface centered on a spherical center of the spherical surface as a lens receiving surface.