JP2017009977A - Underwater photographing lens device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an underwater photographing lens device that can surely anchor a correction lens to a fixed position, and does not generate disadvantageous deformation of images due to the correction lens.SOLUTION: An underwater photographing lens device comprises: an interchangeable lens 2 that is mounted to a camera main body; a dome port 3 that has a dome-shaped light transmission surface, and is provided so that the light transmission surface covers a forward part of the interchangeable lens; one piece of a correction lens 4 that is arranged between th interchangeable lens 2 and the dome port 3, and corrects a peripheral aberration of an image formation plane; a first attachment member 5 that is mounted to the interchangeable lens 4 and serves a lens barrel; and a second attachment member 6 that serves as a lens presser attaching and anchoring the correction lens 4 to a prescribed position in cooperation with the first attachment member, and is anchored thereto to anchor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lens device mounted on a camera for use in underwater photography, and more particularly to an underwater photography lens device using a correction lens for correcting aberrations.

  In underwater photography, cameras are stored in a waterproof housing and carried underwater for photography. This camera is equipped with a dome port for waterproofing the front part. The dome port has a dome-shaped light transmission surface, which acts to provide pressure resistance and wide-angle shooting compatibility.

  On the other hand, optically, since the dome port acts as a lens, aberration may occur on the image forming surface, and the image may be blurred or blurred. In order to suppress such adverse aberrations, Patent Document 1 discloses that a correction lens is disposed between the interchangeable lens (zoom lens) of the camera and the dome port. The correction lens in Patent Document 1 is formed by using two convex lenses, and this acts to impart a positive refractive index to the optical path of the interchangeable lens.

Japanese Patent No. 4393099

  Patent Document 1 describes that the correction lens in which two convex lenses are combined is disposed between the interchangeable lens and the dome port. However, this Patent Document 1 has any structure. It is unclear whether the correction lens is provided between the interchangeable lens and the dome port, and if this is implemented, it is a cause of difficulty in the arrangement structure of the correction lens. In particular, it is not preferable that the correction lens be displaced on the optical path of the optical axis of each part, and it is desired to develop a structure for preventing the inadvertent displacement and securely maintaining the correction lens at a fixed position. ing. In Patent Document 1, two convex lenses are required and must be used in combination. Therefore, it is very difficult to obtain the same shape characteristics of the two convex lenses.

  The present invention has been made in consideration of such problems, and it is possible to reliably fix the correction lens at a fixed position, and without causing aged positional deviation with respect to the peripheral members, in addition, An object of the present invention is to provide a lens device for underwater photography that does not generate aberrations by adopting one correction lens.

  The underwater photographing lens device of the present invention has an interchangeable lens mounted on the camera body, a dome-shaped light transmission surface, and a dome port provided so that the light transmission surface covers the front of the interchangeable lens, One correction lens that is disposed between the interchangeable lens and the dome port and corrects peripheral aberrations of the image plane, a first attachment member that is attached to the interchangeable lens and serves as a lens barrel, and the first And a second mounting member serving as a lens holder for mounting and fixing the correction lens at a predetermined position in cooperation with the mounting member.

  In this case, the outer peripheral edge of the ring-shaped correction lens on the light incident surface side is formed with a notched lens corner in order to secure a large area on the outer periphery, and the ring-shaped lens is provided at the lens corner. When the lens pressing contact portions formed over the entire inner periphery of the press are combined and matched, the lens corner and the lens pressing contact portion have a wide surface contact structure around the entire periphery, and a mirror described later. In combination with the point contact portion with the barrel, a reliable composition of the correction lens can be realized. As will be described later, the correction lens is a single lens having a concave surface on the light incident surface side and a convex lens (convex meniscus lens) on the light output surface side.

  According to the present invention, the outer peripheral edge that is the lens corner on the light incident surface side of the correction lens is brought into contact with the lens pressing contact portion of the lens pressing that is the second mounting member, while the light emitting surface of the correction lens The outer peripheral side portion and the outer peripheral portion are inserted and arranged in the receiving portion of the lens barrel that is the first mounting member, and in this state, the lens presser that is the second mounting member is turned and tightened to fix the correction lens to the first position. 1 is securely fixed to a lens barrel which is an attachment member. The lens barrel as the first mounting member is attached to the interchangeable lens, and the correction lens is disposed at a fixed position between the interchangeable lens and the dome port. By adopting such a structure, the correction lens does not have a positional shift over time with each part in contact with the correction lens, and can be reliably fixed at a fixed position. Therefore, a phenomenon such as inconvenient image deformation in the correction lens. Will also disappear.

It is sectional drawing which shows the whole lens apparatus of one Embodiment of this invention. It is a side view which shows the arrangement | positioning relationship which arranged the interchangeable lens, correction | amendment lens, dome port, etc. in one Embodiment in the axial direction. It is sectional drawing which shows the attachment structure of the attachment member to an interchangeable lens. FIG. 4 is an enlarged sectional view of a part A in FIG. 3.

  1 to 4 show an underwater photographing lens device 1 (hereinafter referred to as a lens device 1) according to an embodiment of the present invention. FIG. 1 is an overall sectional view, and FIG. 2 shows an interchangeable lens and a dome port. It is a schematic side view which shows arrangement | positioning. As shown in FIG. 1, the lens device 1 includes an interchangeable lens 2, a dome port 3, a correction lens 4, and first and second attachment members 5 and 6. In this case, the first mounting member 5 is a lens barrel, and the second mounting member 6 is a lens holder.

  The interchangeable lens 2 is attached to a camera body (not shown) in a replaceable manner. In this case, the interchangeable lens 2 is a zoom lens, such as a focus lens, a variable power lens, an imaging lens, a color separation prism, and the like. A structure is generally constituted by a combination of optical members, and these optical members are arranged inside a casing.

The front side (left side in the figure) of the interchangeable lens 2 is the underwater subject side, and there is an interchangeable lens side threaded portion 7 inside the ring-shaped inner side of the opening on the front side, and this interchangeable lens side threaded portion 7. The lens barrel screw portion 8 of the lens barrel 5 is screwed as shown in the figure, and both can be attached to and detached from each other by the rotation of either the interchangeable lens side screw portion 7 or the lens barrel screw portion 8 side. (See FIG. 4).

  On the other hand, the dome port 3 is disposed so as to cover the front side (the left side in the figure) of the interchangeable lens 2. In this case, the dome port 3 is made of a transparent resin such as polycarbonate resin or acrylic resin, or a material such as glass. The whole is formed. Further, the dome port 3 has a dome shape, and a transmission portion capable of transmitting light covers the front of the interchangeable lens 2.

In this case, the dome port 3 is disposed so that the center of the dome coincides with the optical axis W of the interchangeable lens 2 and the correction lens 4 as shown in FIGS. A tip ring 10 is attached to the tip opening side of the intermediate ring 9 in which the interchangeable lens 2 is housed, and the outer peripheral edge of the dome port 3 is attached to the tip ring 10.

In this case, the intermediate ring 9 is for adjusting the length between the dome port 3 and the correction lens 4 and adopts a cylindrical shape extending in the optical axis W direction. And several intermediate rings 9 may be used as needed. The dome port 3 is firmly attached to a tip ring 10 fixed to the intermediate ring 9, thereby fixing the dome port 3. In this case, each attachment location of the dome port 3, the tip ring 10 and the intermediate ring 9 has a liquid-tight structure.

  The opening side (the left side in FIG. 4) of the lens barrel 5 is annular in the outer circumferential direction, and the space receiving portion 11 is cut out. When viewed in cross section, the space receiving portion 11 forms a staircase structure. The outer peripheral side portion 12 of the correction lens 4 is disposed in the receiving portion 11. Continuing from this staircase structure, a lens barrel opening screw 13 is screwed into the inner periphery of the tip opening (left side in FIG. 4) of the lens barrel 5. The lens holding screw portion 14 of the lens holder 6 (second mounting member) having a substantially trapezoidal cross section is screwed into the lens barrel opening screw 13.

The inner circumference of the lens holder 6 having a substantially trapezoidal cross section is composed of a flat top surface portion X, a slope portion Y following the flat top surface portion X, and a plane portion Z subsequent thereto. When the lens presser 6 is rotated, the lens pressing screw portion 14 is configured to move forward and backward by engaging the lens barrel opening screw portion 13 inwardly or outwardly.

Next, the correction lens 4 is attached between the lens barrel 5 and the lens presser 6 with the light incident surface side of the correction lens 4 set on the dome port 3 side and the light output surface side set on the interchangeable lens 2 side. In this case, the outer periphery of the edge on the light incident surface side of the correction lens 4 is formed with a lens corner H so as to be in surface contact with the inclined surface Y surface by so-called chamfering.

In other words, the outer peripheral surface of the slope portion Y and the outer peripheral surface of the lens corner H facing the same are processed so as to be parallel to each other and become a smooth surface, so that both surfaces can be evenly in surface contact. Surface processing. Similarly, it goes without saying that the outer peripheral surface of the flat portion Z and the outer peripheral surface of the outer peripheral portion 15 of the correction lens 4 are processed and formed so as to be in uniform surface contact. As a result, the surface at the outer periphery of the edge of the correction lens 4 can come into contact with the surface of the lens presser joint K of the lens presser 6 on the correction lens 4 side in a wide range.

As a result, the number of contact points on the surface increases, so that when the correction lens 4 is attached to the lens barrel 5, it does not loosen. In addition, the load on the correction lens 4 is not limited to a single point due to an increase in the number of contact points on the surface, and therefore it is possible to prevent cracking and chipping of the correction lens 4 that tend to occur at the extreme corners of the correction lens. .

The procedure for tightening and attaching the correction lens 4 of the present invention configured as described above to the lens barrel 5 by the lens presser 6 is as follows. First, the ring-shaped outer peripheral portion 15 of the correction lens 4 is installed in the receiving portion 11 of the lens barrel 5. Thereafter, the lens holding screw portion 14 of the lens holder 6 is screwed into the lens barrel opening screw 13.

When the lens retainer 6 is screwed and rotated in this state, the lens retainer 6 advances in the arrow Q direction. As a result, the inclined surface Y comes into contact with the lens corner H of the correction lens 4 at the outer peripheral surface, and when the repulsive force at this contact gradually increases, the outermost periphery of the outer peripheral portion 15 becomes stronger in the direction of the arrow E. Pressed.

As a result, the point where the outer peripheral portion 15 was point contact in the illustrated point contact portion G within the receiving portion 11 gradually becomes surface contact from the point contact, and at these points, a function just like a spring washer becomes a strong correction lens. 4 will be attached. This is because the surface composed of the topmost surface portion X, the inclined surface portion Y, and the flat surface portion Z has a structure in which the surface including the lens corner portion H is widely contacted by surface contact. Can be fixed.

In the case of the present invention, as described above and as shown in FIGS. 3 and 4, the correction lens 4 has a light incident surface side on the dome port 3 side and a concave concave shape, and the light output surface side is an interchangeable lens. Formed by one convex lens (convex meniscus lens) having a convex convex surface on the two sides. Therefore, it also acts to correct aberrations such as field curvature generated on the imaging surface of the camera body.

The present invention is not limited to the above-described embodiment, and it is also effective to make the outer peripheral portion 15 of the correction lens 4 black for preventing irregular reflection and loss of light, and various applications are possible without departing from the scope of the invention. Of course.

DESCRIPTION OF SYMBOLS 1 ... Lens apparatus, 2 ... Interchangeable lens, 3 ... Dome port, 4 ... Correction lens, 5 ... Lens barrel, 6 ... Lens presser, 7 ... Interchangeable lens side screw part, 8 ... Lens barrel screw part, 9 ... Intermediate ring, DESCRIPTION OF SYMBOLS 10 ... Tip ring, 11 ... Receiving part, 12 ... Outer peripheral side part, 13 ... Lens barrel opening screw, 14 ... Lens holding screw part, 15 ... Outer peripheral part, W ... Optical axis, X ... Topmost surface part, Y ... Slope part , K: Lens press contact portion, H: Lens corner, Z: Plane portion, G: Point contact portion

Claims (3)

An interchangeable lens attached to the camera body,
A dome port having a dome-shaped light transmission surface, the light transmission surface provided to cover the front of the interchangeable lens;
A correction lens that is disposed between the interchangeable lens and the dome port and corrects the peripheral aberration of the imaging plane;
A first attachment member mounted on the interchangeable lens and serving as a lens barrel;
A lens device for underwater photography, comprising: a second attachment member serving as a lens holder for attaching and fixing the correction lens at a predetermined position in cooperation with the first attachment member. An inner abutting portion is formed on the lens presser so that the corner flat surface portion on the incident surface side of the correction lens abuts by surface contact, and the vicinity of the outer peripheral portion on the exit surface side of the correction lens abuts on the lens barrel by line contact. The underwater photographing lens device according to claim 1, wherein a receiving portion is formed. 3. The lens device for underwater photography according to claim 1, wherein the correction lens is a single convex lens (convex meniscus lens) having a concave entrance surface and a convex exit surface.

Images