JP2007033958A - Lens driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent erroneous detection by a photosensor for detecting the position of a lens frame. <P>SOLUTION: The lens driving device is equipped with: a base 10 having an aperture part 11 through which subject light passes; lens frames 50 and 60 supported to freely move in an optical axis direction in front of the base 10; the photosensors 100 and 110 fixed on the base 10; pieces to be detected 56 and 66 formed in the lens frames 50 and 60; and a front cover 20 demarcating the moving space S of the lens frame in cooperation with the base 10. The base 10 or the front cover 20 has a separation wall 16 demarcating housing parts 14 and 15 housing the photosensors 100 and 110 separately from the moving space S of the lens frame, and the separation wall 16 has an inserting/pulling-out port 17 through which the pieces to be detected 56 and 66 are inserted in/pulled out from the housing parts 14 and 15. Thus, the entrance of stray light or the like is prevented, the erroneous detection by the photosensor is prevented and also a situation that the detected light by the photosensor reaches an imaging device to cause a ghost phenomenon is prevented. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lens driving device that reciprocates a lens in the optical axis direction, and more particularly to a lens driving device that includes an optical sensor such as a photo interrupter that detects the position of a lens frame.

  Conventional lens driving devices include a base having an opening for fixing an image sensor such as a CCD, and a plurality of lenses arranged in the optical axis direction and held in a lens barrel fixed in front of the base (subject side). Lens frame, an optical sensor having a light emitting element and a light receiving element fixed to the base, a detected piece provided on the lens frame to be detected by the optical sensor, and an object integrated with the lens frame on the subject side of the detected piece Equipped with a light-shielding cover, a drive mechanism that drives the lens frame in the optical axis direction, etc., and stray light of subject light entering the lens barrel from the front is blocked by the light-shielding cover to prevent erroneous detection of the optical sensor What was made is known (for example, refer patent document 1).

  However, in this lens driving device, since the light shielding cover is integrally provided on the lens frame, the lens frame becomes large, and the weight of the lens frame increases, which is preferable as a lens frame for which smooth movement is desired. Absent. In addition, since the optical sensor is disposed in the vicinity of the opening of the base, the detection light emitted from the light emitting element of the optical sensor toward the light receiving element is not limited to being received by the light receiving element. There is a risk that a ghost phenomenon will occur in the captured image by passing through the image sensor such as a CCD.

JP 2003-287666 A

  The present invention has been made in view of the above circumstances, and its object is to reduce stray light or other light sources while simplifying the structure, reducing the number of parts, reducing costs, downsizing, and the like. It is possible to prevent the light sensor from erroneously detecting the light from the light, etc., and also to prevent the detection light of the light sensor from entering the image pickup device such as a CCD and causing a ghost phenomenon, etc. An object of the present invention is to provide a lens driving device that can be driven and obtain a highly accurate captured image.

The lens driving device according to the present invention includes a base having an opening through which subject light passes, a lens frame that is supported in front of the base so as to be movable in the direction of the optical axis and holds the lens, an optical sensor fixed to the base, and an optical sensor A lens driving device comprising: a detected piece formed on the lens frame to be detected by the lens; a front cover that cooperates with the base to define a moving space of the lens frame, wherein the base It has the isolation wall which isolate | separates from a movement space and demarcates the accommodating part which accommodates an optical sensor, The said isolation wall is characterized by having an insertion / removal opening | mouth in which a to-be-detected piece can be inserted / removed with respect to an accommodating part.
According to this configuration, the detected piece of the lens frame moves closer to and away from the optical sensor disposed in the housing portion isolated from the movement space of the lens frame through the insertion / removal port of the isolation wall. Position detection is performed.
As described above, since the optical sensor is arranged in the housing part isolated from the moving space of the lens frame, stray light or light from other light sources can be prevented from entering the optical sensor, and the optical sensor can be erroneously detected. Detection can be prevented. Further, it is possible to prevent the detection light emitted from the light emitting side of the optical sensor from entering the image pickup device such as a CCD disposed behind through the opening of the base and causing a ghost phenomenon or the like.

The said structure WHEREIN: The structure currently formed as the recessed part open | released to the outer side of a base is employable.
According to this configuration, since the optical sensor can be attached to the concave portion (housing portion) from the outside with the base and the front cover assembled, the assembling property can be improved and the productivity can be increased.

The said structure WHEREIN: The structure currently formed in the slit shape extended in an optical axis direction can be employ | adopted for the insertion / extraction opening | mouth.
According to this configuration, when the detected piece enters the accommodating portion (close to the optical sensor) or exits from the accommodating portion (separated from the optical sensor), the insertion / removal port is formed in a slit shape, It is possible to more reliably prevent stray light or detection light from passing through the insertion / removal port.

In the above-described configuration, the insertion / removal port is formed to have an opening in the front in the optical axis direction, and the detection piece extends toward the rear in the optical axis direction so as to be able to enter the housing portion from the front opening. The structure currently formed can be employ | adopted.
According to this configuration, since the detected piece approaches and separates only from the front side in the optical axis direction with respect to the optical sensor arranged in the housing portion, the detection light emitted from the light emitting side of the optical sensor is particularly rearward. It can prevent as much as possible toward the opening part of the base located in.

In the above configuration, the photosensor may employ a configuration in which the light emitting side is arranged in a direction away from the opening of the base.
According to this configuration, the detection light emitted from the light emitting side of the optical sensor can be reliably prevented from going to the opening of the base (and the image pickup device disposed at the rear), and the ghost phenomenon and the like can be more reliably prevented. it can.

In the above configuration, the lens frame includes a plurality of lens frames arranged in the optical axis direction, the optical sensor includes a plurality of optical sensors corresponding to the plurality of lens frames, and the plurality of optical sensors in the optical axis direction. It is possible to adopt a configuration that is arranged adjacent to each other.
According to this configuration, it is possible to prevent the erroneous detection of the optical sensor or the ghost phenomenon of the image sensor as described above, and to arrange a plurality of optical sensors adjacent to each other in the optical axis direction. The size can be reduced, and the assembly of a plurality of optical sensors is facilitated.

  According to the lens driving device having the above-described configuration, the optical sensor erroneously detects stray light or light from other light sources while achieving simplification of the structure, reduction in the number of parts, cost reduction, size reduction, and the like. In addition, it is possible to prevent the detection light of the optical sensor from entering the image pickup device such as a CCD to cause a ghost phenomenon, etc., and the lens can be driven with high accuracy and smoothness, and a high-accuracy captured image can be obtained. A lens driving device can be obtained.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described with reference to the accompanying drawings.
1 to 4 show an embodiment of a lens driving device according to the present invention. FIG. 1 is an exploded perspective view of the device, FIG. 2 is a side view including a partial cross section of the device, and FIG. FIG. 4 is an enlarged cross-sectional view of an optical sensor portion of the apparatus.

  As shown in FIG. 1, this apparatus includes a base 10, a front cover 20 that is joined to the base 10 from the front F and holds the lens G 1, and a guide shaft 30 that is fixed to the base 10 and extends in the optical axis direction L. The rotation stop shaft 40, the lens frame 50 that holds the lens G2, the lens frame 60 that holds the lens G3, the lead screw 70 that moves the lens frame 50 in the optical axis direction L, the nut 71 and the motor 72, and the lens frame 60 are lighted. The position of the lead screw 80, the nut 81, and the motor 82 that are moved in the axial direction L, the coil spring 90 that biases the lens frame 50 and the lens frame 60 toward each other in the optical axis direction L, and the position of the lens frame 50 are detected. The optical sensor 100, the optical sensor 110 which detects the position of the lens frame 60, etc. are provided.

  As shown in FIGS. 1 and 2, the base 10 is formed in a case shape whose outer contour is substantially rectangular, and defines a part of a moving space S in which the lens frames 50 and 60 move in the optical axis direction L. The rear R has an opening 11 through which subject light passes, a mounting portion 12 to which an image sensor E such as a CCD is mounted behind the opening 11, a joint 13 that joins the front cover 20 at the front F, and an optical sensor. The housing portions 14 and 15 for housing 100 and 110, the separating wall 16 for separating the housing portions 14 and 15 from the moving space S of the lens frames 50 and 60, the insertion / removal port 17 formed in the separating wall 16 and the like are provided.

As shown in FIGS. 1 to 4, the accommodating portion 14 accommodates the optical sensor 100 that detects the position of the lens frame 50, is formed as a concave portion that opens to the outside, and is inserted by the isolation wall 16. The region excluding the outlet 17 is formed so as to be isolated from the moving space S of the lens frames 50 and 60.
As shown in FIGS. 1 to 4, the accommodating portion 15 accommodates the optical sensor 110 that detects the position of the lens frame 60, and is adjacent to the accommodating portion 14 in the optical axis direction L and outward. In addition to being formed as a concave portion to be opened, the isolation wall 16 is formed so that the region excluding the insertion / removal port 17 is isolated from the moving space S of the lens frames 50 and 60.
Thus, since the accommodating parts 14 and 15 are formed as the recessed part open | released outside, the optical sensors 100 and 110 can be easily attached or detached with respect to the base 10, and an assembly property improves. In addition, since the two accommodating portions 14 and 15 are arranged adjacent to each other in the optical axis direction L, it is possible to consolidate parts, contribute to downsizing of the apparatus, and the plurality of optical sensors 100 and 110. Easy assembly.

  As shown in FIGS. 1 to 4, the isolation wall 16 is molded so that the outer wall 10 a of the base 10 is recessed inward, and forms a wall surface of the recess (bottom surface of the recess) to at least the optical axis L. In the inward direction toward the opening 11, the accommodating portions 14 and 15 that accommodate the optical sensors 100 and 110 are isolated from the moving space S of the lens frames 50 and 60.

As shown in FIGS. 1 to 4, the insertion / removal port 17 is formed in a slit shape across the housing portions 14 and 15 so as to extend in the optical axis direction L with respect to the isolation wall 16. The detected pieces 56 and 66 of 50 and 60 are allowed to enter the accommodating portions 14 and 15 in a non-contact manner (close to the optical sensors 100 and 110) or to be removed from the accommodating portions 14 and 15 (separated from the optical sensors 100 and 110). ).
Thus, by forming the insertion / removal port 17 in a slit shape, stray light can be reliably prevented from entering the accommodating portions 14 and 15 from the moving space S, and the detection light of the optical sensors 100 and 110 moves. It is possible to reliably prevent the light from entering the space S and reaching the opening 11 (further, the image sensor E).

  As shown in FIGS. 1 and 2, the front cover 20 is formed in a case shape whose outer contour is substantially rectangular, and is joined to the joint portion 13 of the base 10 to cooperate with the base 10 to form a lens. The frames 50 and 60 are formed so as to delimit a moving space S that moves in the optical axis direction L, and a lens G1 is held on the front surface thereof.

  In order to guide the lens frame 50 and the lens frame 60 in the optical axis direction L, the two guide shafts 30 are formed in a columnar shape extending in the optical axis direction L as shown in FIGS. It is fitted to the base 10 and the other end is fitted to the front cover 20 to be firmly fixed.

  The rotation stop shaft 40 restricts the lens frame 50 and the lens frame 60 from rotating in a plane perpendicular to the optical axis L, and extends in the optical axis direction L as shown in FIGS. It is formed in a columnar shape, one end of which is fitted to the base 10 and the other end is fitted to the front cover 20 to be firmly fixed.

  As shown in FIG. 1, the lens frame 50 is disposed on the front side F (near the subject) in the optical axis direction L, and is formed at a position spaced radially from the holding portion 51 that holds the lens G2, and the holding portion 51. A cylindrical connecting portion 52 and a U-shaped connecting portion 53, a nut holding portion 54 that extends from the connecting portion 52 and holds the nut 71 in a non-rotatable manner, and extends from the connecting portion 52. And a latching piece 55 for latching one end 91 of the coil spring 90, a thin plate-like detected piece 56 formed extending from the connecting portion 53 in a direction perpendicular to the optical axis direction L, and the like. .

  As shown in FIG. 1, the lens frame 60 is disposed on the front side F (near the subject) in the optical axis direction L, and is formed at a position that is radially separated from the holding unit 61 that holds the lens G3. A cylindrical connecting portion 62 and a U-shaped connecting portion 63 formed from the connecting portion 62, and a nut holding portion 64 for holding the nut 81 in a non-rotatable manner and extending from the connecting portion 62. And a latch piece 65 for latching the other end 92 of the coil spring 90, a thin plate-like detected piece 66 formed extending from the connecting portion 63 in a direction perpendicular to the optical axis direction L, and the like. Yes.

The lead screw 70 is directly connected to the motor 72 and is rotationally driven, and is screwed into a nut 71 that is non-rotatably held by the lens frame 50. As the motor 72, a stepping motor or the like is employed.
The lead screw 80 is directly connected to the motor 82 and is driven to rotate, and is screwed into a nut 81 that is non-rotatably held by the lens frame 60. Note that a stepping motor or the like is employed as the motor 82.

  As shown in FIG. 1, the coil spring 90 exerts an urging force that draws in the optical axis direction L. One end 91 of the coil spring 90 is hooked on the hooking piece 55 of the lens frame 50, and the other end 922 is hooked on the lens frame 60. It is latched by the latching piece 65. Then, the coil spring 90 has a lens frame in the optical axis direction L so that the nut 71 and the nut holding portion 54 of the lens frame 50 are in close contact, and the nut 81 and the nut holding portion 64 of the lens frame 60 are in close contact. An urging force is exerted in a direction in which 50 and the lens frame 60 are brought close to each other.

As shown in FIG. 4, the optical sensor 100 includes a transmissive optical sensor (photo interrupter) having a light emitting element 101 that emits detection light and a light receiving element 102 that receives the detection light, and a detected piece 56 of the lens frame 50. By detecting the presence or absence of the lens, a predetermined position (here, an initial position) of the lens frame 50 is detected.
And the optical sensor 100 is fitted and attached to the accommodating part 14 of the base 10 from the outer side. As described above, since the optical sensor 100 is disposed in the accommodating portion 14 that is isolated from the moving space S by the isolation wall 16, stray light or light from other light sources is prevented from entering the optical sensor 100. It is possible to prevent erroneous detection of the optical sensor 100. Further, the detection light emitted from the light emitting side (light emitting element 101) of the optical sensor 100 is prevented from entering the image pickup element E such as a CCD disposed behind through the opening 11 of the base 10 to cause a ghost phenomenon or the like. it can.

As shown in FIG. 4, the optical sensor 110 includes a transmissive optical sensor (photo interrupter) having a light emitting element 111 that emits detection light and a light receiving element 112 that receives the detection light, and a detected piece 66 of the lens frame 60. By detecting the presence or absence of the lens, a predetermined position (here, an initial position) of the lens frame 60 is detected.
And the optical sensor 110 is fitted and attached to the accommodating part 15 of the base 10 from the outside. As described above, since the optical sensor 110 is disposed in the accommodating portion 15 that is isolated from the moving space S by the isolation wall 16, stray light or light from other light sources is prevented from entering the optical sensor 110. It is possible to prevent erroneous detection of the optical sensor 110. Further, the detection light emitted from the light emitting side (light emitting element 111) of the optical sensor 110 is prevented from entering the image pickup element E such as a CCD disposed behind through the opening 11 of the base 10 to cause a ghost phenomenon or the like. it can.

The light sensors 100 and 110 are arranged such that the light emitting elements 101 and 111 on the light emitting side are oriented in a direction away from the opening 11 of the base 10.
Thereby, it can prevent more reliably that the detection light which came out of the light emitting elements 101 and 111 of the optical sensors 100 and 110 heads for the opening part 11 (further, image sensor E arrange | positioned back) of the base 10, As a result, it is possible to more reliably prevent a ghost phenomenon or the like from occurring in the captured image of the image sensor E.

  Next, the operation of this apparatus will be briefly described. When the lens frame 50 and the lens frame 60 are in the initial positions (rest positions) retracted rearward R in the optical axis direction L, the optical sensors 100 and 110 are connected to the lens. It is detected with high accuracy that the frames 50 and 60 are located at the initial positions, that is, the lens frames 50 and 60 are at the control start reference positions without causing erroneous detection.

  When the lead screw 70 is rotated by the motor 72 from this initial position, the lens frame 50 moves in the optical axis direction L together with the nut 71, and the lead screw 80 is rotated by the motor 82. When moved, the lens frame 60 moves in the optical axis direction L together with the nut 81.

  At this time, the lens frame 50 (lens G2) and the lens frame 60 (lens G3) are relatively moved in the optical axis direction L by appropriately controlling the rotation amount and the rotation direction of the motor 72 and the motor 82. Performs zooming and focusing operations.

  5 to 9 show another embodiment of the lens driving device according to the present invention. FIG. 5 is an external perspective view of the device, FIG. 6 is an exploded perspective view of the device, and FIG. 7 is a front view of the device. FIG. 8 is a plan view of the apparatus, and FIGS. 9A and 9B are partial cross-sectional views of the apparatus. In this embodiment, the same components as those of the above-described embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIGS. 5 to 9, this apparatus includes a base 10 ′, a front cover 20, two guide shafts 30, two rotation-preventing shafts 40, a lens frame 50 ′, a lens frame 60 ′, and a lens frame 50 ′. The lead screw 70, nut 71 and motor 72 for moving in the optical axis direction L, and the lead screw 80, nut 81 and motor 82 for moving the lens frame 60 'in the optical axis direction L, and the lens frames 50' and 60 'for the optical axis, respectively. A coil spring 90 'biasing in one direction L, an optical sensor 100 for detecting the position of the lens frame 50', an optical sensor 110 for detecting the position of the lens frame 60 ', and the like are provided.

The base 10 ′ is formed thinner than the above-described embodiment, and includes an opening 11, a mounting portion 12, accommodation portions 14 ′ and 15 ′, an isolation wall 16 ′, an insertion / removal port 17 ′, and the like.
The accommodating portions 14 ′ and 15 ′ are formed as concave portions that are open to the outside, and are respectively disposed on both sides of the optical axis L for thinning.
The isolation wall 16 ′ isolates the accommodating portions 14 ′ and 15 ′ that accommodate the optical sensors 100 and 110 from the moving space S of the lens frames 50 ′ and 60 ′.
The insertion / removal port 17 ′ is formed so as to have an opening in the front F in the optical axis direction L, as shown in FIGS. 8 and 9A and 9B.

As shown in FIG. 6, the lens frame 50 ′ is disposed on the front side F (subject to the subject) in the optical axis direction L, and includes a holding part 51, a connecting part 52, a connecting part 53 ′, a nut holding part 54 ′, and a connecting part. A thin plate-like detection piece 56 ′ extending from the outside of 53 ′ toward the rear R in the optical axis direction L is provided.
As shown in FIG. 6, the lens frame 60 ′ is disposed on the front side F (subject to the subject) in the optical axis direction L, and includes a holding portion 61, a connecting portion 62, a connecting portion 63 ′, a nut holding portion 64 ′, and a connecting portion. A thin plate-like detection piece 66 ′ extending from the outside of 63 ′ toward the rear R in the optical axis direction L is provided.

  In other words, in this apparatus, the detected pieces 56 ′ and 66 ′ can enter the housing portions 14 ′ and 15 ′ from the insertion / removal port 17 ′ opened forward, so that the housing portions 14 ′ and 15 The detected pieces 56 ′ and 66 ′ are close to and separated from only the front side F in the optical axis direction L with respect to the optical sensors 100 and 110 arranged at ′. Thereby, in particular, it is possible to prevent the detection light emitted from the light emitting elements 101 and 111 of the optical sensors 100 and 110 from traveling toward the opening 11 of the base 10 'as much as possible.

  Also in this apparatus, as described above, in the optical sensors 100 and 110, the respective light emitting elements 101 and 111 on the light emitting side are arranged so as to be directed away from the opening 11 of the base 10 ′. Thereby, it is possible to more reliably prevent the detection light emitted from the light emitting elements 101 and 111 from going to the opening 11 of the base 10 ′ (and the imaging element E disposed behind), and as a result, the imaging element E It is possible to more reliably prevent a ghost phenomenon or the like from occurring in the captured image.

  In this embodiment, since the optical sensor 100 and the motor 72, and the optical sensor 110 and the motor 82 are respectively disposed on both sides of the optical axis L, the apparatus can be made thinner than the above-described embodiment.

  In the above embodiment, the case where the present invention is adopted in the configuration including the two lens frames 50 and 60 (50 ′ and 60 ′) moving in the optical axis direction L is shown, but the present invention is not limited to this. Alternatively, the present invention can be adopted in a configuration including one lens frame that moves in the optical axis direction L or three or more lens frames.

  As described above, the lens driving device of the present invention can prevent the erroneous detection of the optical sensor while achieving simplification of the structure, reduction of the number of parts, reduction of cost, miniaturization, etc. Since it can prevent the ghost phenomenon, it can be applied as a lens drive device for a portable ordinary digital camera or a silver salt film camera, as well as a lens drive device for a fixed camera or other lens optical system. Useful.

It is a disassembled perspective view which shows one Embodiment of the lens drive device which concerns on this invention. It is a side view including the partial cross section of the apparatus shown in FIG. It is sectional drawing which looked at the apparatus shown in FIG. 1 from the front. It is the expanded sectional view which expanded the area | region of the optical sensor of the apparatus shown in FIG. 1 partially. It is an external appearance perspective view which shows other embodiment of the lens drive device which concerns on this invention. It is a disassembled perspective view of the apparatus shown in FIG. It is sectional drawing which looked at the apparatus shown in FIG. 5 from the front. It is a front view except a part of apparatus shown in FIG. 5A and 5B show an operation state of the apparatus shown in FIG. 5, in which FIG. 5A is a partial cross-sectional view showing a state in which the lens frame is retracted backward, and FIG. 5B is a partial cross-sectional view showing a state in which the lens frame is extended forward. It is.

Explanation of symbols

10, 10 'Base 11 Opening portion 12 Mounting portion 13 Joint portion 14, 14', 15, 15 'Housing portion 16, 16' Separation wall 17, 17 'insertion / removal port 20 Front cover 30 Guide shaft 40 Anti-rotation shaft 50, 50 ', 60, 60' Lens frame 52, 53, 53 ', 62, 63, 63' Connecting portion 56, 66, 56 ', 66' Detected piece 70, 80 Lead screw 71, 81 Nut 72, 82 Motor 90, 90 'Coil spring L Optical axis direction E Image sensor

Claims (6)

A base having an opening through which subject light passes, a lens frame that is supported in front of the base so as to be movable in the direction of the optical axis and holds the lens, a light sensor fixed to the base, and detected by the light sensor Therefore, a lens driving device comprising: a detected piece formed on the lens frame; and a front cover that defines a moving space of the lens frame in cooperation with the base;
The base has an isolation wall that defines an accommodating portion that accommodates the optical sensor while being isolated from a moving space of the lens frame;
The isolation wall has an insertion / removal port through which the detected piece can be inserted into and removed from the housing portion.
A lens driving device. The accommodating portion is formed as a recess that opens to the outside of the base.
The lens driving device according to claim 1. The insertion / removal port is formed in a slit shape extending in the optical axis direction,
The lens driving device according to claim 1 or 2, wherein The insertion / removal port is formed to have an opening in the front in the optical axis direction,
The detected piece is formed to extend toward the rear in the optical axis direction so as to be able to enter the accommodating portion from the opening.
The lens driving device according to claim 1 or 2, wherein The light sensor is arranged with its light emitting side oriented in a direction away from the opening of the base,
The lens driving device according to claim 1, wherein The lens frame includes a plurality of lens frames arranged in an optical axis direction,
The photosensor includes a plurality of photosensors corresponding to the plurality of lens frames,
The plurality of optical sensors are disposed adjacent to each other in the optical axis direction.
The lens driving device according to claim 1, wherein the lens driving device is a lens driving device.

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