JP2010145504A - Lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve space efficiency to reduce the size of a lens barrel by eliminating, in a lens caulking part, a structure for attaching a thin fixed diaphragm member for shielding unwanted light other than effective light beam by adhesion, welding or the like, and fixing the fixed diaphragm member while suppressing floating or wrinkling thereof as much as possible. <P>SOLUTION: In the lens barrel, the outer shape of a ring sheet-like metallic light shielding member which is colored to prevent reflection of light is formed to conform to the lens holding diameter of a lens holding frame. When a lens is caulked and fixed, the light shielding member is put on the lens, and the light shielding member surface is thermally caulked, whereby the lens and the light shielding member are simultaneously fixed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lens barrel that holds and fixes a lens to a lens holding frame by heat staking, a lens barrel having a light shielding member for blocking unnecessary light on the heat squeezing surface of the lens, and the lens barrel The present invention relates to an optical device provided.

In conventional lens barrels, harmful light rays outside the effective rays that cause flare and ghosts are covered by covering the periphery of the lens when the caulking part for holding and fixing the lens of the lens holding frame is caulked (unnecessary) A structure in which a light-shielding part that blocks light is integrally formed with the crimped part, or after holding and fixing the lens by crimping, the ring-sheet-shaped light shielding member is fixed to the holding frame by a fixing method such as adhesion or welding It is a structure to do. (For example, refer to Patent Document 1 and Patent Document 2.)
Patent registration No. 2803401 (2nd page, FIG. 2) Japanese Patent Laying-Open No. 2003-35860 (page 9, FIG. 3)

  In recent years, optical devices equipped with lens barrels are required to be further miniaturized in order to improve portability and ease of storage, and the distance between the lens groups of the lens barrel must be narrower. Has been.

  However, in the conventional light shielding structure for the lens caulking portion of the lens barrel, when the lens is thermally caulked to the lens holding frame, the light shielding portion that covers the lens periphery and blocks unnecessary light is replaced by the caulking portion. There is a structure that is integrally molded with. However, it is difficult to make the light-shielding portion thin in order to maintain the moldability and light-shielding property. Further, in the method of fixing the ring sheet light-shielding member to the holding frame by bonding or welding after holding and fixing the lens by heat caulking, a space having a shape for attaching the light-shielding member is required. Furthermore, it is necessary to secure a space in consideration of the floating and wrinkles of the light shielding member. An object of the present invention is to eliminate the structure for attaching a fixed diaphragm member having a small thickness for shielding unnecessary light outside the effective light beam by bonding or the like in the lens caulking portion, thereby allowing the fixed diaphragm member to float or wrinkle. By limiting and fixing as much as possible, space efficiency is improved and the lens barrel is downsized.

  In the present invention, the outer shape of the ring-shaped metal light-shielding member colored in order to prevent light reflection is made to coincide with the lens holding diameter of the lens holding frame, and the light-shielding member is placed on the lens when the lens is caulked. The lens surface and the light shielding member are fixed at the same time by heat-clamping the member surface.

  According to the present invention, there is no need for a structure space for fixing a light shielding member that blocks harmful light (unnecessary light) other than an effective light beam that causes flare or ghost by adhesion or welding, and the light shielding member is attached to the lens surface. It can be tightly fixed to. In addition, since the light shielding member is a metal material, the light shielding member is elastically deformed into a substantially frustoconical shape that is rotationally symmetric with respect to the optical axis along the curved surface of the lens by heat caulking, and the lens is attached to the holding frame with a spring. Can be fixed by force. Therefore, a small and thin lens that cannot set a high pressure for plastic deformation of the holding frame during caulking can be held without play. As described above, it is possible to reduce the size of the lens barrel having a fixed diaphragm for blocking unnecessary light in the caulking portion and the mounted optical apparatus.

  Examples of the present invention will be described below.

  FIG. 1 is an exploded perspective view showing a lens barrel of an embodiment of the present invention, and FIG. 2 is a sectional view. For the sake of explanation, some shapes are omitted.

  In this figure, 1 is a first group barrel, 2 is a second group barrel, 3 is a third group barrel, 4 is a fourth group barrel, 5 is an image sensor holding frame, 7 is a focus sensor, 8 is an iris unit, 9 is a zoom drive motor, 10 is a zoom rack, and 11 is a zoom sensor.

  Reference numeral 12 denotes a focus drive motor, 13 a focus rack, 14 screws, 15 a focus rack spring, 16 a zoom rack spring, and 17 a first guide bar.

  18 is a filter frame, 19 is a second guide bar, 20 is a filter frame rack, 21 is a filter frame rack spring, 22 is a filter frame drive motor, 23 is an infrared cut filter, 24 is an ND filter, 25 is a filter frame sensor, 26 is a dummy glass, and 27 is a light shielding mask.

  The zoom drive motor 9, the focus drive motor 12, and the filter frame drive motor 22 are stepping motors.

  The overall configuration of the lens barrel will be described with reference to FIGS. The first group barrel 1 includes a lens holding portion, and fixes and holds a first lens group (not shown) by adhesion or heat caulking.

  The second group barrel 2 holds a second lens group (not shown), the focus rack 13 and the focus rack rack spring 15 are attached to the attachment portion 2a, and the sleeve portion 2b and the U groove portion 2c are respectively provided to the first group barrel 1. Are guided by two guide bars 17 supported by the fourth group barrel 4. The second group barrel 2 is restricted by the guide from moving in directions other than the direction parallel to the optical axis. A focus rack 13 is screwed onto a shaft of a focus drive motor 12 attached to the first group barrel 1 with screws 14. With the above configuration, the second group barrel 2 is moved in the optical axis direction by the drive of the focus drive motor 12 to perform focusing. At this time, the reset position of the second group barrel 2 is defined by the focus sensor 7 attached to the first group barrel 1.

  The third group barrel 3 holds a third lens group (not shown), the zoom slack 10 and the zoom rack spring 16 are attached to the attachment portion 3a, and the sleeve portion 3b and the U groove portion 3c are the first guide bar. The movement in a direction other than the optical axis is regulated by the guide 17. The third group barrel 3 is driven by the zoom drive motor 9 by the guide and moves in the optical axis direction. A zoom rack 10 is screwed onto a shaft of a zoom drive motor 9 attached to the fourth group lens barrel 4 with screws 14. The zoom sensor 11 is a sensor that detects the position of the third group barrel 3, determines the amount of movement of the third group barrel 3 based on this signal, and zooms by moving the third group barrel 3.

  The iris unit 8 is fixed to the fourth group lens barrel 4 with screws 14, and adjusts the opening diameter on the optical axis by moving a built-in blade to adjust the amount of light entering the image sensor.

  The filter frame 18 has three openings, and only the infrared cut filter 23, the infrared cut filter 23, the ND filter 24, and the dummy glass 26 are attached to the openings.

  The filter frame 18 is guided so that the sleeve portion can be moved in a direction perpendicular to the optical axis by a second guide bar 19 held at both ends of the image sensor holding frame 5. Further, a filter frame rack 20 and a filter frame rack spring 21 are attached to the filter frame 18, and the filter frame rack 20 is screwed with a shaft portion of the filter drive motor 22, so that the shaft of the filter frame drive motor 22 rotates. Is driven in the guide direction. Reference numeral 25 denotes a filter frame sensor, which moves the filter frame 18 to a predetermined position by a signal from the filter frame sensor 25. Therefore, since the filter frame 18 moves in a direction perpendicular to the optical axis, the filter located on the light beam can be switched, and the wavelength of the light beam entering the image sensor can be adjusted. That is, for example, when shooting a bright subject in the daytime or the like, the infrared cut filter 23 or the opening to which the infrared cut filter 23 and the ND filter 24 are attached is positioned on the light beam to obtain an image with good color reproducibility. . On the other hand, in the case of an object with low illuminance such as at night, it is possible to increase the amount of light by placing the dummy glass 26 on the luminous flux and passing infrared light. The dummy glass 26 is used to match the optical path length with that when the infrared cut filter 23 is inserted.

  The light shielding mask 27 is fixed to the fourth group lens barrel 4 by heat caulking the light shielding mask surface together with a fourth lens group (not shown).

  Next, the light shielding mask 27 for blocking unnecessary light will be described.

  FIG. 3 is a front view of the light shielding mask 27. The light shielding mask 27 is fitted with the fourth lens group fitting diameter of the fourth group barrel 4 at the outer diameter portion 27a, and is filled with the thermoplastic material of the barrel by heat caulking to hold and fix the lens. It has a notch 27b.

  FIG. 4 is a cross-sectional view of the light-shielding mask 27 at a fitting portion 27a with the lens barrel in a state where the light-shielding mask 27 is caulked and fixed to the fourth lens barrel 4 together with the fourth lens group. Further, the light shielding mask is elastically deformed into a substantially frustoconical shape that is rotationally symmetric with respect to the optical axis along the lens curved surface, and shows a state in which the lens is spring-biased with respect to the holding frame.

  FIG. 5 is a cross-sectional view of the light shielding mask 27 in the cutout portion 27b of the light shielding mask 27 in a state where the light shielding mask 27 is caulked and fixed to the fourth group barrel 4 together with the fourth lens group. The state in which the thermoplastic material is filled and the lens is fixed is shown.

  FIG. 6 shows an electrical configuration of the camera body in the imaging apparatus of the present invention.

  Reference numeral 230 denotes a solid-state image sensor such as a CCD, and 224 denotes a drive source for the variable power lens unit L3, which includes a stepping motor 9. Reference numeral 222 denotes a drive source for the focusing lens group L2, and includes the stepping motor 12. Reference numeral 225 denotes a drive source for the filter group L5 including an infrared cut filter and a dummy glass, and includes a stepping motor 22.

  Reference numeral 223 denotes an aperture driving source, which includes a meter 8c. 228 is a zoom encoder for detecting the position in the optical axis direction of the variable power lens unit L3 as a variator, 226 is a focus encoder for detecting the position in the optical axis direction of the focusing lens unit L2, and 229 is a filter including an infrared cut filter It is an infrared cut filter encoder for detecting the optical axis orthogonal direction position of the group L5. These encoders respectively detect the absolute position of the zoom lens L3 and the focusing lens L2 in the optical axis direction and the absolute position of the filter group L5 including the infrared cut filter in the orthogonal direction of the optical axis. In the present invention, the zoom reset switch 11, the focus reset switch 7, and the filter frame reset switch 25, which are photo interrupters, are used.

  The zoom drive source 224, the focus drive source 222, and the filter drive source are not limited to stepping motors, and DC motors or vibration motors can be used to detect the positions of the second and third lens groups L2 and L3. Therefore, a detection method other than the encoder may be employed to detect the position of the filter group L5.

  When a stepping motor is used as a drive source as in the present invention, a method of counting the number of operation pulses input to the stepping motor after arranging a holding frame at a certain reference position is generally used.

  An aperture encoder 227 is known which has a Hall element disposed inside the meter 8c, which is an aperture drive source disposed outside the lens barrel, and detects the rotational positional relationship between the rotor and the stator.

  Two diaphragm blades 8a and 8b are driven by the diaphragm drive source 8c to adjust the light amount. In addition, an ND filter is attached to the aperture blade in order to prevent image quality deterioration due to small aperture diffraction.

  Or what drives this ND filter by another drive source is known.

  Reference numeral 231 denotes a camera signal processing circuit which performs predetermined amplification and gamma correction on the output of the CCD 230. The contrast signal of the video signal subjected to these predetermined processes passes through the AE gate 232 and the AF gate 233. That is, an optimum signal extraction range for determining exposure and focusing is set in this gate in the entire screen. There are cases where the size of the gate is variable or a plurality of gates are provided, but details thereof are not described here for simplicity.

  Reference numeral 234 denotes an AF signal processing circuit for AF (autofocus), which generates one or a plurality of outputs related to high-frequency components of the video signal. Reference numeral 236 denotes a zoom switch, and reference numeral 237 denotes a zoom tracking memory, which stores information on a focusing lens position to be taken in accordance with a subject distance and a zoom lens position when zooming. Note that a memory in the CPU may be used as the zoom tracking memory. Reference numeral 235 denotes a CPU.

  For example, when the photographer operates the zoom switch 236, the CPU 235 maintains a predetermined positional relationship between the variable power lens unit L3 and the focusing lens unit L2 calculated based on information in the zoom tracking memory 237. Drive control. That is, the zoom drive source 224 and the focusing drive source 222 are driven and controlled so that the absolute position in the optical axis direction of the third lens unit L3 obtained from the detection result of the zoom encoder 228 matches the calculated position. . Similarly, the zoom drive source 224 and the focusing drive source 222 are driven and controlled so that the absolute position in the optical axis direction of the focusing lens unit L2 obtained from the detection result of the focus encoder 226 matches the calculated position. is there.

  In the autofocus operation, the CPU 235 controls the focusing drive source 222 so that the output of the AF signal processing circuit 234 has a peak.

  Further, in order to obtain an appropriate exposure, the CPU 235 controls the aperture driving source 223 so as to obtain a predetermined value of the average value of the output of the Y signal that has passed through the AE gate 232 and an output predetermined value of the aperture encoder 227 to control the aperture diameter. Control. The filter driving source 225 is controlled to switch the filter L5 located on the light beam, thereby adjusting the wavelength range of the light beam entering the image sensor.

  In the above configuration, the ring sheet-shaped light blocking member that blocks unnecessary light on the lens crimping surface can be arranged and fixed efficiently without requiring a structure for adhesion or welding, and is not necessary on the lens crimping surface. A lens barrel having a light blocking member that blocks light can be reduced in size. In addition, an optical device using this lens barrel can be reduced in size.

  The present invention can be applied to, for example, a lens barrel or an optical device used in a 35 mm film photographic camera, a digital still camera, a video camera, or the like.

The exploded perspective view for explanation of the example of the present invention. Sectional drawing for description of this invention. The front view seen from the optical axis direction of the light shielding member which shows the Example of this invention. Sectional drawing of the lens-barrel fitting part in the crimping state of the light shielding member which shows the Example of this invention. Sectional drawing of the notch part in the crimping state of the light shielding member which shows the Example of this invention. 2 is a diagram showing an electrical configuration of a camera body in the imaging apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st group barrel 2 2nd group barrel 3 3rd group barrel 4 4th group barrel 5 Imaging element holding frame 7 Focus sensor 8 Iris unit 9 Zoom drive motor 10 Zoom rack 11 Zoom sensor 12 Focus drive motor 13 Focus rack 14 Screw DESCRIPTION OF SYMBOLS 15 Focus rack spring 16 Zoom rack spring 17 1st guide bar 18 Filter frame 19 2nd guide bar 20 Filter frame rack 21 Filter frame rack spring 22 Filter frame drive motor 23 Infrared cut filter 24 ND filter 25 Filter frame sensor 26 Dummy Glass,
27 Shading mask

Claims (5)

  In the lens barrel that holds and fixes the lens to the lens holding frame by heat caulking, a ring-shaped light shielding member for blocking unnecessary light is arranged on the heat caulking surface of the lens, and the lens barrel is fixed by heat caulking. A lens barrel having a fixed aperture.   The lens barrel according to claim 1, wherein the fitting diameter of the light shielding member with respect to the lens holding frame is the same as the fitting diameter for holding the lens.   The light-shielding member is a metal material, and by heat-clamping, the light-shielding member is elastically deformed into a substantially truncated cone shape that is rotationally symmetric with respect to the optical axis along the lens curved surface, and the lens is fixed to the holding frame with a spring bias. The lens barrel according to claim 1, wherein the lens barrel is formed.   The diameter which fits with the holding frame of a light-shielding member is filled with the thermoplastic material of the holding frame by heat caulking, and has a notch for holding and fixing the lens. The lens barrel according to Crab.   An optical apparatus using the lens barrel according to any one of claims 1 to 4.

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