WO2008056534A1

WO2008056534A1 - Lens cemera cone

Info

Publication number: WO2008056534A1
Application number: PCT/JP2007/070610
Authority: WO
Inventors: Hiromu Umeda
Original assignee: Konica Minolta Opto, Inc.
Priority date: 2006-11-09
Filing date: 2007-10-23
Publication date: 2008-05-15
Also published as: JP5146319B2; JPWO2008056534A1

Abstract

This invention provides a lens camera cone which can maintain good optical properties while maintaining environmental resistance. In this lens camera cone, an outer frame member is formed of “a crystalline plastic” having excellent environmental resistance. By virtue of this, even when a camera is exposed, for example, to ultraviolet light of the sun, rainfall, snowfall, and snow melting agents, in such a state that the camera is exposed outside a car, a lens part within the camera can be protected for a long period of time. On the other hand, an internal frame member is formed of “a noncrystalline (or) amorphous plastic” which has inferior environmental resisitance but has lower moisture absorption as compared with the outer frame member. Accordingly, even when the camera is used under highly humid conditions, the deformation of the internal frame member can be prevented to suppress the occurrence of a rickety state in the lens. Further, a construction may also be adopted in which the lens held in the internal frame member is formed of the same material as the internal frame member to render the coefficient of linear expansion of the lens identical to that of the internal frame member to suppress the occurrence of a rickety state in the lens.

Description

Specification

Lens barrel

Technical field

TECHNICAL FIELD [0001] The present invention relates to an imaging lens barrel, and more particularly to an in-vehicle lens barrel that is suitable for use in an environment that directly touches the outside air and has a large temperature and humidity change.

Background art

[0002] Imaging devices such as digital cameras and shooting in rainy weather are often protected by a cover, so the lens barrel that holds the lens is usually considered for environmental performance. There is little to be done. Therefore, the lens barrel is composed of one kind of material considering moisture absorption characteristics (see Patent Document 1).

Patent Document 1: Japanese Patent Laid-Open No. 2005-274633

Disclosure of the invention

Problems to be solved by the invention

[0003] Meanwhile, in recent years, a camera or the like that displays an image on the rear side or on the passenger seat side that supports the operation of the driver is mounted on the vehicle. Here, in-vehicle cameras are always exposed to the harsh environment of being exposed to the sun's ultraviolet rays, rainfall, snowfall, and snow melting agents. Therefore, it is conceivable that the lens barrel exposed to the outside world is composed of, for example, PPA (polyphthalamide) which is a “crystalline plastic” having excellent environmental performance. However, the forces S and PP A have relatively high hygroscopicity, so when used as a lens barrel, even if it is precisely adjusted during assembly, swelling deformation occurs when used in a high humidity environment. There is a risk of looseness between the holding lens and optical characteristics.

[0004] The present invention has been made in view of power and problems of the related art, and an object of the present invention is to provide a lens barrel capable of maintaining good optical characteristics while maintaining environmental performance. Means to solve the problem

[0005] The lens barrel of the present invention is a lens barrel that holds a plurality of lenses! /, And an outer frame member that supports at least a first lens group having a first lens closest to the subject, Outer frame And an inner frame member that supports the second lens group disposed behind the first lens group, and the first resin material forming the outer frame member includes the inner frame member. It is different from the second resin material to be formed.

[0006] According to the present invention, the first resin material forming the outer frame member is different from the second resin material forming the inner frame member. With respect to the outer frame member exposed to the outside world, the first resin material having environmental performance can be used to suppress the influence from the outside world and ensure durability, and also to hold the second lens group. With respect to the frame member, by using the second resin material having low hygroscopicity, it is possible to suppress the backlash of each lens constituting the second lens group by suppressing the deformation of the inner frame member.

[0007] The first resin material is preferably superior in environmental performance compared to the second resin material. Here, “environmental performance” means at least one of chemical resistance, high strength, and heat resistance.

[0008] Preferably, the outer frame member and the inner frame member are connected by screw connection!

[0009] If the first lens is made of glass, it is superior in environmental performance compared to a resin lens, so that the performance can be maintained even when exposed to the outside world.

[0010] The linear expansion coefficient of the material of the lens constituting the second lens group is equal to the linear expansion coefficient of the second resin material. ! /

The invention's effect

[0011] According to the present invention, it is possible to provide a lens barrel capable of maintaining good optical characteristics while maintaining environmental performance.

Brief Description of Drawings

FIG. 1 is a block diagram of an imaging apparatus 100.

2 is a cross-sectional view of the optical system 101. FIG.

FIG. 3 is a cross-sectional view of the optical system 101 which is a force in a modified example.

Explanation of symbols

[0013] 10 lens barrel

11 Outer frame member

11a Inner peripheral step l ib Inner circumference guide

11c Female thread

12 Inner frame member

12a 1st inner peripheral step

12b Second inner peripheral step

12b Male thread

12c Peripheral guide

12e 3rd inner circumference step

100 imaging device

101 optics

102 Solid-state image sensor

103 Conversion unit

104 Control unit

106 Timing generator

107 Image sensor driver

108 Image memory

109 Image processor

110 Image compression unit

111 Image recording unit

112 Display

113 Control section

L1 first lens

L2 second lens

L3 3rd lens

L4 4th lens

LS lens

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. See Figure 1 and Figure 2 A description will be given of an imaging apparatus 100 equipped with an embodiment of the present invention, in which a lens barrel is mounted. FIG. 1 is a block diagram of the imaging apparatus 100. The imaging apparatus 100 can be mounted on a vehicle in a form in which at least the optical system 101 is exposed to the outside.

As shown in FIG. 1, an imaging apparatus 100 includes an optical system 101, a solid-state imaging device 102, an A / D conversion unit 103, a control unit 104, a timing generation unit 106, and an imaging device driving unit. 107, an image memory 108, an image processing unit 109, an image compression unit 110, an image recording unit 111, a display unit 112 that is a display in a passenger compartment, and an operation unit 113.

The optical system 101 has a function of forming a subject image on the imaging surface of the solid-state imaging device 102. The solid-state imaging device 102 is an imaging device such as a CCD or CMOS, and photoelectrically converts incident light for each of R, G, and B and outputs an analog signal thereof. The A / D conversion unit 103 converts an analog signal into digital image data.

The control unit 104 controls each unit of the imaging apparatus 100. The control unit 104 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory). The control unit 104 cooperates with various programs read from the ROM and expanded in the RAM, and the CPU. Perform various processes.

[0018] Timing generation section 106 outputs a timing signal for analog signal output. The imaging element driving unit 107 performs scanning driving control of the solid-state imaging element 102.

The image memory 108 stores image data so as to be readable and writable. The image processing unit 109 performs various image processes on the image data. The image compression unit 110 compresses captured image data by a compression method such as JPEG (Joint Photographic Experts Group). The image recording unit 111 records image data on a recording medium such as a hard disk or a memory card set in a slot (not shown).

The display unit 112 is a color liquid crystal panel or the like, and can display image data after shooting, a through image before shooting, various operation screens, and the like. The operation unit 113 includes various operation keys for setting values, and outputs information input by the driver to the control unit 104.

Here, the operation of the imaging apparatus 100 will be described. Here, the case where the subject on the rear side of the vehicle is monitored (through image display) will be described. For example, when the vehicle equipped with the imaging device 100 selects the back gear to move backward, the solid-state imaging device 102 is The subject image on the rear side of the vehicle, which is scanned and driven by the timing generation unit 106 and the image sensor driving unit 107 and formed on the light receiving surface of the solid-state image sensor 102 via the optical system 101, is photoelectrically converted, and this output is output. An analog signal is output for one screen at regular intervals.

The analog signal is appropriately gain-adjusted for each RGB primary color component, and then converted into digital data by the A / D conversion unit 103. The digital data is subjected to color process processing including pixel interpolation processing and γ correction processing by the image processing unit 109, and a digital luminance signal Υ and color difference signals Cb, Cr (image data) are generated to generate an image. The signal is stored in the memory 108, and the signal is periodically read out to generate the video signal. The video signal is output to the display unit 112 and can be visually recognized by the driver.

[0023] This monitoring unit 112 functions as an electronic viewfinder in monitoring, and displays captured images in real time.

[0024] In such a monitoring state, still image data is acquired by the driver operating the button of the operation unit 113 or at the command of the in-vehicle computer at the timing at which still image shooting is desired. You can also In response to this, one frame of image data stored in the image memory 108 is read out and compressed by the image compression unit 110. The compressed image data is recorded on a recording medium by the image recording unit 111.

FIG. 2 is a cross-sectional view showing an example of the optical system 101 according to the present embodiment, and the lower half is omitted. The optical system 101 includes a lens unit LS and a lens barrel 10. The lens unit LS is a force that is arranged in the order of the negative first lens Ll, negative second lens L2, diaphragm S, positive third lens L3 from the subject side (left side in Fig. 2). it can. As a general in-vehicle optical system, it is preferable to use a wide-angle lens having a focal length of 38 mm or less in terms of 35 mm film.

The lens barrel 10 includes a hollow cylindrical outer frame member 11 and an inner frame member 12. The cylindrical outer frame member 11 is fixed to the inner peripheral step portion 11a on the subject side by caulking and fixing the flange portion of the first lens L1 closest to the subject side while being positioned in the optical axis direction and the optical axis orthogonal direction (adhesion) But good). The first lens L1 is made of glass. Further, the outer frame member 11 has an inner peripheral guide portion ib and a female screw portion 11c having a larger diameter than the inner peripheral guide portion ib on the inner periphery thereof. In the present embodiment, the first resin material forming the outer frame member 11 is environmental performance PPA (polyphthalamide), which is a “crystalline plastic” with excellent chemical resistance, high strength, and heat resistance, is used. In this example, the first lens L1 corresponds to the first lens group.

[0027] The cylindrical inner frame member 12 includes a first inner peripheral step portion 12a on the subject side and a second inner peripheral step portion 12b on the imaging element side having a smaller diameter. At the time of assembly, the flange portion of the third lens L3 inserted from the subject side is first clamped and fixed (it may be glued) in the state where it abuts against the second inner peripheral step portion 12b, and then the first inner portion from the subject side. Insert the outer periphery of the stop S into the circumferential step 12a and abut it, then abut the flange of the second lens L2 from above and fix it by crimping (adhesion may be used). As a result, the second lens L2 and the third lens L3 are positioned relative to the inner frame member 12 in the optical axis direction and the optical axis orthogonal direction. In the present embodiment, the second resin material forming the inner frame member 12 is made of PC (polycarbonate) having low hygroscopicity / “non-crystalline (or non-crystalline) plastic”. Yes. In this example, the second lens L2 and the third lens L3 correspond to the second lens group.

[0028] Furthermore, the inner frame member 12 has an outer peripheral guide portion 12c that engages with the inner peripheral guide portion l ib of the outer frame member 11, and a male screw portion 12d that is screwed into the female screw portion 11c. By fitting the inner peripheral guide portion l ib and the outer peripheral guide portion 12c, the outer frame member 11 and the inner frame member 12 are positioned in the direction perpendicular to the optical axis. In addition, by changing the screwing amount of the female screw portion 11c and the male screw portion 12d, the distance between the first lens L1 and the second lens L2 is adjusted, and the light receiving surface of the solid-state imaging element 102 is in focus. Images can be formed.

[0029] According to the present embodiment, since the outer frame member 11 is a PPA excellent in environmental performance with respect to the PC, it is exposed to the sun's ultraviolet rays, rainfall or snowfall, and a snow melting agent while being exposed outside the vehicle. Even when exposed to the like, the internal lens portion can be protected for a long period of time. In addition, since the first lens L1 located closest to the subject is made of glass, there is an advantage that it is excellent in weather resistance, which is difficult to be damaged.

[0030] On the other hand, the inner frame member 12 supporting the second lens L2 and the third lens L3 is inferior to PP A in environmental performance but has low hygroscopicity! Even when used in high humidity! / Situations, it is possible to suppress the deformation of the inner frame member 12 and to suppress the backlash of the second lens L2 and the third lens L3. Also, the second lens L2 and the third lens L3 are the same as the inner frame member 12. Since the linear expansion coefficient is equalized by forming the material, the amount of deformation can be equalized even when the temperature changes, so that the play of the second lens L2 and the third lens L3 can be suppressed. The first resin material forming the frame member 11 is not limited to the above-mentioned PPA, but may be PA-MXD6 (polyamide MXD6) which is “crystalline plastic”. In addition, the second resin material forming the inner frame member 12 is not limited to the above-mentioned PC, but “non-crystalline (or non-crystalline)

[0031] As a combination of the first resin material forming the outer frame member 11 and the second resin material forming the inner frame member 12, for example, PPA is used for the outer frame member 11, and PC is used for the inner frame member 12. Combination of PPA for outer frame member 11, combination of PAR for inner frame member 12, PA—MX D6 for outer frame member 11, PC combination for inner frame member 12, PA—MXD6, inner frame member for outer frame member 11 12 can be combined with PAR.

[0032] It should be noted that the outer frame member 11 and the inner frame member 12 can be coupled by a force S coupled by screwing of the threaded portion, not limited to this, but by adhesion, laser welding, or the like. Furthermore, although the optical system of the single focus lens has been described here, the inner frame member may be movable with respect to the outer frame member to form a focusing lens or a zoom lens.

FIG. 3 is a cross-sectional view of the optical system 101 according to the modification, and the lower half is omitted. In this modification example, the lens unit LS includes a negative first lens L1 (corresponding to the first lens group) from the subject side (left side in FIG. 3), a negative second lens L2, a positive third lens L3, Aperture S and negative fourth lens L4 (corresponding to the second lens group) are arranged in this order. Further, the inner frame member 12 forms a first inner circumferential step portion 12a, a second inner circumferential step portion 12b, and a third inner circumferential step portion 12e, which are sequentially reduced in diameter from the subject side. At the time of assembly, the flange portion of the fourth lens L4 inserted from the subject side is first crimped and fixed (adhesion is possible) in a state where it abuts against the third inner peripheral step portion 12e, and then the second side from the subject side. Insert the outer periphery of the stop S into the inner peripheral step 12b and fix it by abutting and tightening (adhesion may be used), and then insert the second lens L2 into the first inner peripheral step 12a from the subject side and thrust each other Clamp and fix the flange part by caulking (adhesion may be good! /). As a result, the second lens L2, the third lens L3, the stop S, and the fourth lens L4 are positioned relative to the inner frame member 12 in the optical axis direction. Since other configurations are the same as those in the above-described embodiment, the description thereof is omitted. In the above embodiment, the first lens group supported by the outer frame member 11 is composed of one lens, and the second lens group supported by the inner frame member 12 is composed of a plurality of lenses. The first lens group is composed of multiple lenses, the second lens group is composed of a single lens, and the first lens group and the second lens group are composed of multiple lenses. It may have been made. That is, the outer frame member 11 and the inner frame member 12 only need to support at least one lens. In addition, when the first lens group supported by the outer frame member 11 is composed of a plurality of lenses, it is preferable that the first lens L1 disposed closest to the subject is made of glass.

The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate. For example, in the above-described embodiment, the lens barrel used in the in-vehicle image pickup apparatus has been described as an example. However, the present invention is not limited to this, and the power to be used in an image pickup apparatus for a monitoring camera or a mobile phone is not limited. it can.

Claims

The scope of the claims

[1] A lens barrel that holds multiple lenses! /

An outer frame member that supports at least the first lens group having the first lens closest to the subject; and an inner frame member that is included in the outer frame member and supports the second lens group that is disposed behind the first lens group. A frame member,

The lens barrel, wherein the first resin material forming the outer frame member is different from the second resin material forming the inner frame member.

[2] The lens barrel according to claim 1, wherein the first resin material is superior in environmental performance compared to the second resin material.

[3] The lens barrel according to [1] or [2], wherein the outer frame member and the inner frame member are connected by screw connection.

[4] The lens barrel according to any one of claims 1 to 3, wherein the first lens is made of glass.

[5] The force according to any one of claims 1 to 4, wherein the linear expansion coefficient of the material of the lens constituting the second lens group is equal to the linear expansion coefficient of the second resin material. The lens barrel according to Item 1.