JP2005258238A - Omniazimuth type objective lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an omniazimuth type objective lens which is made lightweight thereby made low-cost and can be mass-produced. <P>SOLUTION: The omniazimuth type objective lens is equipped with: an object light incident surface 11a formed in annular and curved surface shape; a 1st reflection surface 12a formed in annular and curved surface shape so as to reflect the light passing through the incident surface 11a; and a 2nd reflection surface 13a reflecting the light reflected by the 1st reflection surface 12a so as to emit it. The objective lens is formed of a shell body 10 made of resin demarcating a prescribed space, and the shell body 10 is formed by bonding a 1st shell body unit 11 having the incident surface 11a, a 2nd shell body unit 12 having the 1st reflection surface 12a, and a 3rd shell body unit 13 having the 2nd reflection surface 13a. Thus, the cost of the objective lens is reduced in comparison with the cost of an objective lens formed of glass material, and the mass-production thereof is realized. Since the inside of the shell body is hollow, contraction deformation or shrinkage or the like after molding is prevented, then, dimensional accuracy is enhanced, and desired optical characteristic is obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an omnidirectional objective lens mounted on a camera or the like capable of photographing an omnidirectional subject, and in particular, an omnidirectional objective lens mounted on a monitoring camera or the like that captures and monitors all 360 degrees. About.

As a conventional camera (image capturing device) capable of photographing in all directions, as shown in FIG. 4, a camera composed of an omnidirectional objective lens 1, a relay lens 2, an image sensor 3, and the like is known. Yes. The omnidirectional objective lens 1 includes a peripheral light-transmitting surface 1a on which subject light is incident at a position off the central axis L, and a peripheral light-shielding surface 1b having a reflective surface that reflects subject light that has passed through the peripheral light-transmitting surface 1a. A central light shielding surface 1c having a reflective surface for reflecting the reflected light reflected by the peripheral light shielding surface 1b toward the relay lens 2, a central light transmitting surface 1d for passing the reflected light reflected by the central light shielding surface 1c, and the like are defined. Therefore, it is formed of a solid glass material (see, for example, Patent Document 1).
JP 2000-004383 A

  By the way, the conventional omnidirectional objective lens 1 has a problem that it is made of a glass material, is heavy, is expensive, and cannot be mass-produced at the same time. On the other hand, it is conceivable that the omnidirectional objective lens 1 is molded using a resin material instead of a glass material. However, if the omnidirectional objective lens 1 is formed into a solid shape, the thickness becomes thick, and distortion due to shrinkage, sink marks, etc. after molding. Or a nest etc. generate | occur | produce and there exists a problem that desired dimensional accuracy cannot be obtained.

  The present invention has been made in view of the above circumstances, and the object thereof is omnidirectional in which cost can be reduced, mass production is possible, dimensional accuracy is ensured, and desired optical characteristics are obtained. Is to provide a mold objective lens.

An omnidirectional objective lens according to the present invention includes an object light incident surface formed in a ring shape and a curved surface, a first reflection surface formed in a ring shape and a curved surface so as to reflect light passing through the incident surface, An omnidirectional objective lens comprising: a second reflecting surface that reflects the light reflected by the one reflecting surface to emit the light, wherein the incident surface, the first reflecting surface, and the second reflecting surface are in a predetermined space. It is characterized by being formed of a resin shell body that defines.
According to this configuration, since the incident surface, the first reflecting surface, and the second reflecting surface are formed by the resin shell, the cost can be reduced and mass production can be achieved as compared with the case of being formed by the glass material. In addition, since the inside of the shell is hollow, shrinkage deformation or sink after molding can be prevented to improve dimensional accuracy, and desired optical characteristics can be obtained.

In the above configuration, the shell may employ a configuration including a first shell unit that forms the incident surface and the second reflection surface, and a second shell unit that forms the first reflection surface.
According to this configuration, since the shell body is formed by the two parts of the first shell body unit and the second shell body unit, the shell body can be easily molded, and each can be formed with high accuracy. be able to.

In the above configuration, the shell includes a first shell unit that forms an incident surface, a second shell unit that forms a first reflective surface, a third shell unit that forms a second reflective surface, It is possible to adopt a configuration including:
According to this configuration, since the shell is formed by the three parts of the first shell unit, the second shell unit, and the third shell unit, the shell can be more easily molded, Can be formed with higher accuracy.

The said structure WHEREIN: The structure which the opening part which radiate | emits the light reflected by the 2nd reflective surface is formed in the 2nd shell unit is employable.
According to this configuration, since the internal space of the shell communicates with the external space through the opening, the atmosphere of the internal space of the shell and the external space can be made the same, and therefore due to the difference in atmosphere Changes in optical characteristics can be prevented.

The said structure WHEREIN: The structure by which the level | step-difference part for attachment is formed in the joining area | region of a 1st shell body unit and a 2nd shell body unit is employable.
According to this configuration, when this omnidirectional objective lens is attached to a case or the like, it can be easily attached because it can be positioned by this stepped portion.

In the above configuration, the incident surface is formed to have a negative angle that allows subject light from a direction closer to the first reflecting surface to be incident on a plane perpendicular to the central axis of the first reflecting surface and the second reflecting surface. It is possible to adopt the configuration.
According to this configuration, since subject light can be captured over a wide field of view, an omnidirectional objective lens suitable for an omnidirectional surveillance camera or the like can be obtained.

  According to the omnidirectional objective lens having the above configuration, the weight can be reduced, the cost can be reduced, mass production can be performed, dimensional accuracy can be ensured, and desired optical characteristics can be obtained.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described with reference to the accompanying drawings.
1 and 2 show an embodiment of an omnidirectional objective lens according to the present invention. FIG. 1 is a sectional view of the omnidirectional objective lens, and FIG. 2 is a surveillance camera equipped with the omnidirectional objective lens. FIG.

  As shown in FIGS. 1 and 2, the omnidirectional objective lens includes a shell 10 that is molded of a resin material and defines a predetermined space (cavity) inside. The shell 10 includes a first shell unit 11 that defines an incident surface 11a for subject light, and a second shell unit 12 that defines a first reflecting surface 12a that reflects light that has passed through the incident surface 11a. The third shell unit 13 that defines the second reflecting surface 13a that reflects the light reflected by the first reflecting surface 12a to be emitted is joined to each other.

  The first shell unit 11 is molded to a predetermined thickness with a transparent resin material, and has an annular and curved surface (for example, a spherical surface) so as to face 360 ° in all directions as shown in FIG. The object light incident surface 11a is defined on the surface thereof. The incident surface 11a can receive subject light entering from the direction of the angle θ close to the first reflecting surface 12a with respect to the plane S perpendicular to the central axis L of the first reflecting surface 12a and the second anti-slope 13a. It is formed so as to form a negative angle. In this way, by setting the negative angle θ, it is possible to capture subject light over a wide field of view.

The second shell unit 12 is molded to a predetermined thickness with a transparent or opaque resin material, and is substantially symmetrical with the first shell unit 11 as shown in FIGS. 1 and 2. In addition, it is formed in a curved surface (for example, a spherical surface), and the first reflecting surface 12a is defined on the inner surface thereof. The 1st reflective surface 12a reflects the light which passed the incident surface 11a toward the 2nd anti-slope 13a. The first reflecting surface 12a may be formed by performing a predetermined process such as film formation or coating after molding.
The second shell unit 12 defines a circular opening 12b that emits the light reflected by the second anti-slope 13a in a region centered on the central axis L, and the first shell unit 11 Is formed so as to define a mounting step 12c.
Thus, by providing the opening 12b, the atmosphere of the inner space and the outer space of the shell can be made the same, and therefore, the change in optical characteristics due to the difference in atmosphere can be prevented.

  The third core unit 13 is molded to a predetermined thickness with a transparent or opaque resin material, and faces the opening 12b of the second shell unit 12 as shown in FIGS. Thus, it is formed in a curved surface (for example, spherical surface) shape, and defines the second reflecting surface 13a on its inner surface. The second anti-slope 13a reflects the light reflected by the first reflecting surface 12a in a direction substantially along the central axis L so as to be emitted from the opening 12b, and passes through the relay lens 20 on the downstream side to the CCD 30 as an imaging device. The image is formed. The second anti-slope 13a may be formed by performing a predetermined process such as film formation or coating after molding.

  As described above, the first shell unit 11, the second shell unit 12, and the third shell unit 13 molded in each of the second shell 13, the center of the second anti-slope 13 a and the opening 12 b on the central axis L. In addition, the shells are joined to each other by an adhesive or the like so that the centers of the incident surface 11a and the first reflecting surface 12a are positioned to form a rotationally symmetric shell body with respect to the central axis L.

  Thus, since the omnidirectional objective lens 10 is formed of a resin shell having a cavity, it can be reduced in weight, cost can be reduced, and mass production can be achieved as compared with the case of being formed of a glass material. It becomes possible. Moreover, since this shell is formed by joining three shell units 11, 12, and 13 that are individually molded, it is possible to prevent shrinkage deformation or sink marks after molding and to increase the thickness of each shell unit. The dimensional accuracy can be increased and desired optical characteristics can be obtained.

The omnidirectional objective lens 10 is attached to an opening 41 of a cylindrical case 40 in which the relay lens 20 and the CCD 30 are arranged as shown in FIG. That is, the stepped portion 12c is abutted and positioned against the annular flange 41a of the case 40, and then firmly fixed using an adhesive or other fixing means. Thus, by providing the step part 12 c in the second shell unit 12, the step part 12 c can be used for positioning and can be easily attached to the case 40.
The omnidirectional objective lens 10, the relay lens 20, the CCD 30, and the case 40 form a surveillance camera capable of monitoring all directions. The surveillance camera is placed on various places for surveillance, for example, on a table in a conference table, or on the ceiling in the opposite direction.

FIG. 3 shows another embodiment of the omnidirectional objective lens according to the present invention. The same reference numerals are given to the same components as those in the previous embodiment, and the description thereof is omitted.
That is, as shown in FIG. 3, the omnidirectional objective lens is made of a shell body 10 'molded with a resin material and defining a predetermined space (cavity) inside. The shell 10 'reflects the first shell unit 11' that defines the incident surface 11a and the second reflection surface 11b of the subject light, and the second reflection surface 11b that reflects the light that has passed through the incident surface 11a. The second shell unit 12 that defines one reflective surface 12a is formed by joining together.

    The first shell unit 11 'is molded to a predetermined thickness with a transparent resin material, and has an annular and curved surface (for example, a spherical surface) so as to face 360 ° in all directions as shown in FIG. The object light incident surface 11a is defined on the surface thereof. A second reflecting surface 11b is defined on the inner surface of the region centered on the central axis L. The second anti-slope 11b reflects the light reflected by the first reflecting surface 12a in a direction substantially along the central axis L so as to be emitted from the opening 12b, and passes through the relay lens 20 on the downstream side to the CCD 30 as an image sensor. The image is formed. After the first shell unit 11 is molded, the second anti-slope 11b is formed by applying a predetermined process such as forming or coating a film that functions as a reflective surface.

  As described above, the first shell unit 11 ′ and the second shell unit 12 molded in each of the first shell unit 11 ′ and the second shell unit 12 on the center axis L are the center of the second anti-slope 11 b and the opening 12 b, the incident surface 11 a and the first shell unit 11. They are joined to each other by an adhesive or the like so that the center of the reflecting surface 12a is located, thereby forming a rotationally symmetric shell with respect to the central axis L.

  In this way, since the omnidirectional objective lens 10 'is formed of a resin shell having a cavity, the weight can be reduced, the cost can be reduced, and mass production can be achieved compared to the case of being formed of a glass material. Is possible. In addition, since the shell is formed by joining two individually molded shell units 11 'and 12, shrinkage deformation or sink marks after molding can be prevented and the respective thickness dimensions can be reduced. The accuracy can be improved, desired optical characteristics can be obtained, the number of parts can be reduced as compared with the above-described embodiment, the number of assembling steps can be reduced, and the management cost of parts can be reduced.

In the above embodiment, as the resin shells 10 and 10 ', three individually molded shell units 11, 12, and 13 or two shell units 11' and 12 are joined. You may employ | adopt what joins the shell unit shape | molded by the number of other than that, respectively.
In the above embodiment, in the second shell unit 12, the circular opening 12b is provided in the region through which the central axis L passes. However, the light transmitting surface may be formed by covering with a transparent resin material.
In the above embodiment, the case where the mounting step 12c is provided in the second shell unit 12 is shown, but it may be provided in the first shell units 11 and 11 '.

  As described above, the omnidirectional objective lens of the present invention can be applied to a monitoring camera for monitoring all directions, as long as it is a camera that is desired to shoot over a wide field of view. It can also be used in photographing cameras and other optical systems used for purposes other than monitoring.

It is sectional drawing which shows one Embodiment of the omnidirectional objective lens which concerns on this invention. It is sectional drawing of the surveillance camera provided with the omnidirectional objective lens shown in FIG. It is sectional drawing which shows other embodiment of the omnidirectional objective lens which concerns on this invention. It is sectional drawing which shows the conventional omnidirectional objective lens.

Explanation of symbols

10,10 Omnidirectional objective lens (shell)
11, 11 ′ First shell unit 11a Incident surface 11b Second anti-slope 12 Second shell unit 12a First reflective surface 12b Opening portion 12c Stepped portion 13 Third shell unit 13a Second reflective surface 20 Relay lens 30 CCD
40 Case 41 Opening 41a Annular flange L Center axis S Plane perpendicular to center axis

Claims (6)

An object light incident surface formed in a ring shape and a curved surface, a first reflection surface formed in a ring shape and a curved surface so as to reflect light passing through the light incident surface, and light reflected by the first reflection surface An omnidirectional objective lens comprising: a second reflecting surface that reflects to emit light;
The incident surface, the first reflecting surface, and the second reflecting surface are formed of a resin shell that defines a predetermined space.
An omnidirectional objective lens. The shell includes a first shell unit that forms the incident surface and the second reflection surface, and a second shell unit that forms the first reflection surface.
The omnidirectional objective lens according to claim 1, wherein: The shell includes a first shell unit that forms the incident surface, a second shell unit that forms the first reflective surface, and a third shell unit that forms the second reflective surface. ,
The omnidirectional objective lens according to claim 1, wherein: In the second shell unit, an opening for emitting the light reflected by the second reflecting surface is formed.
The omnidirectional objective lens according to claim 2 or 3, wherein: A stepped portion for attachment is formed in a joining region between the first shell unit and the second shell unit.
The omnidirectional objective lens according to claim 2, wherein the objective lens is an omnidirectional objective lens. The incident surface is formed so as to have a negative angle at which subject light from a direction closer to the first reflecting surface can enter a plane perpendicular to the central axis of the first reflecting surface and the second reflecting surface. ing,
An omnidirectional objective lens according to any one of claims 1 to 5, wherein:

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