JP2004145029A - Optical unit and imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical unit which makes a collapsible lens thinner, and to provide an imaging device having the optical unit. <P>SOLUTION: The collapsible optical unit allows a second group lens frame 13 to move along the light axis direction with respect to a fixing ring 15 and a back barrel 17 and is provided with a solid imaging element 24 on the rear of the second group lens frame 13. A retracting means 88 which allows an IR-cutting filter 91 to be linearly moved in an intersecting direction from the light axis L and retracts the filter 91 outside the light axis L when the optical unit collapses into barrel is disposed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a collapsible optical unit capable of moving an optical system between a use position and a storage position, and an imaging apparatus such as a digital still camera and a digital video camera equipped with the optical unit. By retracting the optical filter in the direction intersecting the optical axis during collapsing, an optical unit configured to realize a thin collapsible lens by, for example, inserting a lens frame or the like of a focus lens into the retracted space. The present invention relates to an imaging device including the optical unit.
[0002]
[Prior art]
2. Description of the Related Art In recent years, imaging devices such as digital still cameras and digital video cameras have been required to have improved portability and ease of use, and miniaturization of the entire device has been pursued. Also, miniaturization of lenses and lenses has been promoted. Furthermore, there is a strong demand for higher quality and higher resolution of the captured image, and even though the lens, which is a component of the optical system, is large, the drive mechanism is downsized to reduce the size of the optical lens barrel. Miniaturization may be required.
[0003]
Also, with respect to so-called collapsible lenses used in imaging devices such as digital still cameras and digital video cameras, miniaturization and thinning are demanded from the viewpoint of convenience of portability. Further, in an imaging device such as a digital still camera or a digital video camera, a solid-state imaging device such as a CCD or a CMOS receives an image of a subject formed by an optical system barrel, and photoelectrically converts the received light. And outputs digital data corresponding to the image of the subject.
[0004]
Here, a solid-state imaging device such as a CCD or a CMOS captures a geometric pattern (hair, striped pattern, tile pattern, or the like) finer than the periodic array of the imaging element in order to perform geometrically discrete sampling. There is a problem that a false color signal, moiré, and the like are generated, and an unnatural feeling is generated in the image. In order to remove the unnecessary high frequency components, blurring is generally performed by an optical low-pass filter. As described above, in the optical low-pass filter, various “bocus” means using a diffraction phenomenon, birefringence, spherical aberration, and the like have been proposed and implemented.
[0005]
In addition, since solid-state imaging devices such as CCDs and CMOSs generally have high sensitivity not only in visible light but also in the infrared region, correct color reproduction cannot be performed unless unnecessary infrared regions are blocked. An infrared cut filter is used to block this unnecessary infrared light. The infrared cut filter draws not only infrared light but also a gentle absorption curve from orange to red, and plays a role in adjusting color reproduction in the long wavelength region. Also plays. In addition to an absorption type using glass or plastic, there is a type of infrared cut filter that reflects transmitted infrared rays by multi-coating and cuts transmitted light.
[0006]
In an image pickup apparatus such as a general digital still camera and a digital video camera, an infrared cut filter is used in order to pursue high color reproducibility as described above (for example, see Patent Document 2). This infrared cut filter can be arranged in the optical path and can be removed from the optical path. In addition, by irradiating an object with infrared light using an infrared light or the like, a flash device such as a flash or a lighting device can be used even in a completely dark environment in which an image capturing device such as a normal digital still camera or a digital video camera cannot capture images. It is also possible to shoot without using a light emitting device such as ("Night Shot Function").
[0007]
In addition, the present applicant has recently proposed not only the above-described night shot function (infrared photographing function) but also framing in the dark and natural color by moving an infrared cut filter in and out of the optical axis of the lens in synchronization with focus. A function (“night framing function”) that makes image recording compatible with a computer has been developed. This is to capture an image with natural color reproduction by retracting the infrared cut filter outside the optical axis during framing.
[0008]
FIG. 5 is a perspective view showing the external appearance of a retracted position of a lens provided with a retractable lens, for example, when a digital still camera is not used, that is, a retracted position of the lens. FIG. 6 is a perspective view showing the state of use of the camera with the lens barrel extended, at a wide (wide angle) position or a tele (telephoto) position.
[0009]
7A, 7B and 7C and FIGS. 8A, 8B and 8C show conventional collapsible lenses. That is, FIGS. 7A, 7B, and 7C show external shapes of the optical unit of the retractable lens. FIG. 7A is a perspective view showing a retracted state, FIG. 7B is a perspective view showing a wide state, and FIG. 8A is a sectional view showing a lens storage position when not in use, FIG. 8B is a sectional view showing a wide (wide angle) position, and FIG. 8C is a sectional view showing a tele (telephoto) position. FIG. 9 is an exploded perspective view of the retractable lens.
[0010]
First, main functions of the digital still camera will be described with reference to FIGS. Reference numeral 1 denotes a camera main body of the digital still camera, and reference numeral 2 denotes a collapsible imaging lens unit provided on a front surface of one side of the camera main body 1. In the retracted state in FIG. 5A, the front lens surface of the imaging lens unit 2 is protected by the barrier 3. Further, on the front side of the camera body 1, a finder lens 4, a strobe 5, and an auto-focus auxiliary light receiving section 6 for detecting a distance to a subject are arranged. Reference numeral 7 denotes a finder window, 8 denotes a shutter button, and 9 denotes a mode switching knob.
[0011]
Next, a detailed configuration of the imaging lens unit 2 that is a retractable optical unit will be described with reference to FIGS. 7A, 7B, and 8A, 8B, and 8C. The collapsible optical unit shown here is of a type that does not allow nighttime photographing (a type not equipped with a night shot function).
[0012]
Reference numeral 10 denotes a first group lens frame that holds a plurality of lenses 11, and the first group lens frame 10 includes a plurality of cam pins 10 a that are fitted into first cam grooves 12 a of a cam ring 12. The first lens group frame 10 is formed of, for example, a black polycarbonate resin containing glass fiber, and has strength and light shielding properties.
[0013]
Reference numeral 13 denotes a second group lens frame that holds a plurality of lenses 13a. The second group lens frame 13 includes a plurality of cam pins 13b that are fitted into the second cam grooves 12b of the cam ring 12. The second lens frame 13 is formed of, for example, a black polycarbonate resin containing glass fiber, and has strength and light shielding properties. In addition, the second group lens frame 13 may constitute an iris shutter mechanism in some cases.
[0014]
The above-described cam ring 12 includes a gear portion 12c for rotationally driving within the inner diameter of the fixed ring 15 by the gear 14a of the gear unit 14, and a plurality of cam pins 12d fitted into the cam grooves 15a of the fixed ring 15. I have. The cam ring 12 is formed of, for example, a black polycarbonate resin containing glass fiber, and has strength and light shielding properties. The first cam groove 12a and the second cam groove 12b perform a zooming operation of moving the first group lens frame 10 and the second group lens frame 13 along the predetermined curve in the optical axis L direction.
[0015]
Reference numeral 16 denotes a linear guide ring, which is a member that moves in the direction of the optical axis L inside the fixed ring 15 integrally with the cam ring 12. The rectilinear guide ring 16 includes a plurality of guide grooves 16a for guiding the first group lens frame 10 in the optical axis direction and a plurality of guide grooves 16b for guiding the second group lens frame 13 in the optical axis direction. The straight guide ring 16 is formed of, for example, a black polycarbonate resin containing glass fiber, and has strength and light shielding properties.
[0016]
The fixed ring 15 is a member fixed to the rear barrel 17. The fixed ring 15 is formed of, for example, a black polycarbonate resin containing glass fiber, and has strength and light shielding properties.
[0017]
Reference numeral 18 denotes a third lens group frame holding a lens 19. The third group lens frame 18 is formed of, for example, a black polycarbonate resin containing glass fiber, and has strength and light shielding properties. The third lens group frame 18 is held movably in the optical axis direction with respect to the rear barrel 17, and is slightly displaced in the optical axis direction by a power source such as a stepping motor (not shown).
[0018]
The fixed ring 15, the barrier drive mechanism 20, and the gear unit 14 are fixed to the rear barrel 17. Also, an optical filter 22 composed of an optical low-pass cut filter or an infrared cut filter is elastically urged by a seal rubber 23 to a holding portion 21 which faces the third lens frame 18 in the rear barrel 17. Positioning is fixed. Further, a solid-state imaging device 24 such as a CCD or a CMOS is positioned and fixed to the rear lens barrel 17 behind the optical filter 22.
[0019]
The barrier drive mechanism 20 is a protrusion member for closing and driving the barrier 3 in conjunction with the collapse of the imaging lens unit 2. The gear unit 14 rotates the cam ring 12 via a gear 14a that meshes with the gear portion 12c. The gear ratio of the gear unit 14 is in a collapsed state → wide state → tele state and tele state → wide state → retracted state. It is determined so that sufficient driving force can be obtained in the range.
[0020]
Next, the operation of the above-described imaging lens unit 2 will be described.
In the operation between the collapsed state in FIG. 8A and the wide position in FIG. 8B, the cam ring 12 is driven by the gear 14a of the gear unit 14 meshed with the gear portion 12c by a drive source such as a DC motor. The cam pin 12d moves toward the subject along the optical axis L while rotating along the cam groove 15a of the fixed ring 15. At this time, the linear guide ring 16 moves in the direction of arrow A integrally with the cam ring 12.
[0021]
At the same time, the cam pin 10a of the first lens group 10 moves in the direction of arrow B along the first cam groove 12a of the cam ring 12 and the guide groove 16a of the linear guide ring 16. At the same time, the cam pin 13b of the second lens group frame 13 moves in the direction of arrow C along the second cam groove 12b of the cam ring 12 and the guide groove 16b of the rectilinear guide ring 16. With the above operation, the first lens group frame 10 and the second lens group frame 13 are optically at the wide position.
[0022]
8C, the cam ring 12 is driven by the gear unit 14. In this range, the cam pin 12d moves in the horizontal cam groove 15b of the cam groove 15a. Since the cam ring 12 does not move in the optical axis direction, the straight guide ring 16 does not move in the optical axis direction as shown by the arrow D. At this time, the cam pins 10a of the first lens group 10 move in the direction of the arrow E along the cam grooves 12a of the cam ring 12 and the guide grooves 16a of the linear guide ring 16.
[0023]
At the same time, the cam pins 13b of the second lens group frame 13 move in the arrow F direction along the cam grooves 12b of the cam ring 12 and the guide grooves 16b of the linear guide ring 16. With the above operation, the first lens group frame 10 and the second lens group frame 13 perform the zooming operation by optically moving between the wide position and the tele position. Note that, from the tele position to the wide position, and from the wide position to the retracted state, the cam ring 12 is rotated in the reverse direction by driving the gear 14a of the gear unit 14 in the reverse rotation.
[0024]
Here, when the first group lens frame 10 and the second group lens frame 13 perform the zooming operation, the third group lens frame 18 is minutely moved in the optical axis direction by another driving source (not shown) such as a stepping motor. To perform the focusing operation.
[0025]
In the retracted state of the conventional retractable lens having such a configuration, the thickness of the optical filter itself, such as an optical low-pass cut filter or an infrared cut filter, and the thickness of the portion where the optical filter is inserted and fixed, the third lens group frame. The range in which 18 can move in the direction of the solid-state imaging device 24 such as a CCD or CMOS is restricted. There is also a certain limit regarding the distance that can be brought closer between the third lens frame 18 and the second lens frame 13 and between the second lens frame 13 and the first lens frame 10.
[0026]
If the third lens group frame 18 is moved to a position where it comes into contact with the rear lens barrel 17 (the part where the optical filter is inserted and fixed), the third lens group frame 18 is moved between the second lens group frame 13 and the second lens group frame 13-1. Even if the lens frames 10 were brought close to contact with each other, the entire retracted length of the imaging lens unit 2 (retractable lens) could be reduced only to a certain limit.
[0027]
Further, the optical filter 22 is used as an optical filter in a state where the infrared cut filter is bonded to the optical low-pass filter, and is fixed to the rear barrel 17. Therefore, the infrared cut filter cannot be moved in and out of the optical axis, so that nighttime photographing cannot be performed.
[0028]
Next, with reference to FIGS. 10A, 10B, 10C, 11A, 11B, 12 and 13, an imaging lens which is a collapsible optical unit according to the prior art of a type capable of taking a picture at night (with a night shot function). The detailed configuration of the unit 2 will be described. This night shooting (night shot) is a technique that is made possible by putting an infrared cut filter on and off the optical axis. Since the configuration of the entire optical unit is the same as that of the retractable optical unit of the above-described type (without the night shot function) that cannot perform nighttime photographing, the same portions are denoted by the same reference numerals and description thereof will be omitted.
[0029]
As shown in FIGS. 12 and 13, the rear barrel 17 </ b> A is provided with a substantially rectangular parallelepiped casing 71 at a substantially central portion of a surface facing the fixed ring 15. Inside the casing 71, there is provided a filter housing portion 72 for disposing an optical filter (in this embodiment, an infrared cut filter 91) at an appropriate position in the optical axis direction of the lens. An opening 73 is provided on the front surface of the casing 71 corresponding to the filter housing section 72 so as to allow incident light from the object side to pass through the solid-state imaging device 24 such as a CCD or CMOS held by the rear barrel 17A. Is provided.
[0030]
On the upper surface of the casing 71, a retreat port 74 for retreating the infrared cut filter 91, which is a specific example of the optical filter stored in the filter storage portion 72, in a direction orthogonal to the optical axis L is provided. I have. A pair of guide portions 75, 75 for appropriately guiding the infrared cut filter 91 in a direction orthogonal to the optical axis when the infrared cut filter 91 moves by receiving power is provided on both sides of the retreat opening 74. Is provided.
[0031]
Further, a power source mounting portion 77 to which a power source 76 for generating power for moving the infrared cut filter 91 is mounted is provided at an oblique upper portion on one surface of the rear barrel 17A. As the power source 76, for example, a stepping motor can be applied, and a flange portion 76b for mounting to the power source mounting portion 77 is provided on the side where the rotating shaft 76a protrudes. The power source 76 is mounted on the rear barrel 17A by fixing the flange portion 76b to the power source mounting portion 77 with fixing means such as mounting screws. At this time, the rotating shaft 76a is inserted into the bearing hole 77a.
[0032]
A rotation pin 78 is integrally provided on a rotation shaft 76a of the power source 76 via an arm 78a. The rotation pins 78 are displaced by a predetermined distance from the rotation shaft 76a by the arm portions 78a and are made parallel to each other. Further, a fan-shaped gear 79 having a gear portion 79a provided on a part of the outer peripheral edge is attached to the tip of the rotating shaft 76a. At the center of the sector gear 79, an engagement hole 79b into which the rotation shaft 76a and the rotation pin 78 are inserted is provided. When the rotation shaft 76a and the rotation pin 78 are simultaneously engaged with the engagement holes 79b, the rotation of the rotation shaft 76a causes the sector gear 79 to rotate integrally.
[0033]
A pinion gear 80 rotatably supported by a pivot 76c provided on the flange portion 76b meshes with a gear portion 79a of the sector gear 79. An arm 80a is provided on a part of the outer periphery of the pinion gear 80, and a drive pin 81 protruding toward the power source 76 is attached to the arm 80a. The power source 76, the rotation pin 78, the sector gear 79, the pinion gear 80, and the drive pin 81 constitute a power transmission mechanism 83 for moving the filter holder 82.
[0034]
These sector gears 79 and the like are arranged between the rear barrel 17A and the power source 76, and are positioned and driven so as to obtain predetermined performance. Note that the power transmission mechanism 83 is not limited to the above-described gear train and the like, and for example, a cam mechanism, a link mechanism, and various other mechanisms capable of transmitting power can be used.
[0035]
The filter holder 82 holds the infrared cut filter 91 and moves the filter in a direction perpendicular to the optical axis L. The filter holder 82 has a U-shaped holding portion 82a to which the infrared cut filter 91 is mounted. . Protrusions 82b are provided on both outer surfaces on the opening side of the holding portion 82a to lock a mounting band 84 that closes the opening. Further, on the opposite side of the holding portion 82a of the filter holder 82, an elongated hole 82c into which the drive pin 81 is slidably engaged is provided.
[0036]
Further, on the side opposite to the opening side of the holding portion 82a of the filter holder 82, there is provided a guide protrusion 82d that is guided by the guide portion 75 of the casing 71 when the filter holder 82 is moved in a direction perpendicular to the optical axis L. . As a material of the filter holder 82, for example, it can be molded using a polycarbonate resin containing glass fiber, and has strength, light shielding properties, and mass productivity.
[0037]
The mounting band 84 is formed of an elastic member such as a rubber-like elastic body, and has a pair of engaging holes 84a that are engaged with the projections 82b. The attachment band 84 is provided with an urging portion 84b that elastically urges the infrared cut filter 91 to prevent the infrared cut filter 91 from falling off when the band is attached. By attaching the mounting band 84 to the opening side with the infrared cut filter 91 mounted on the holding portion 82a, the infrared cut filter 91 is positioned at a predetermined position and held by the filter holder 82.
[0038]
The method of holding the infrared cut filter 91 is not limited to the snap-fitting method using the mounting band 84, but may be a method using thermal caulking or an adhesive, or other various methods.
[0039]
Since the infrared cut filter 91 is held in the filter holder 82 and is moved in the direction orthogonal to the optical axis L, in the present embodiment, unlike the case of the conventional collapsible lens, the optical low pass cut filter 85 Are formed independently as separate members.
[0040]
The optical low-pass cut filter 85 is necessary for image recording of the image pickup apparatus even at nighttime photographing such as infrared photographing. Therefore, in the present embodiment, the solid-state imaging device 24 mounted in the center hole of the rear barrel 17A is disposed on the front side in the optical axis direction, and is positioned and fixed at a predetermined position.
[0041]
The power transmission mechanism 83 and the filter holder 82 constitute a moving mechanism 86 that moves the infrared cut filter 91 between a position on the optical axis and a position outside the optical axis. The moving mechanism 86 and the casing 71 constitute a retracting means 88 for linearly moving the infrared cut filter 22 from a predetermined position on the optical axis in the orthogonal direction and retracting the infrared cut filter 22 to a predetermined position outside the optical axis.
[0042]
The operation of the retracting means 88 will be briefly described as follows. First, a case where the infrared cut filter 91 is moved from a position on the optical axis to a position outside the optical axis will be described. First, the drive source 76 is driven to rotate the rotation shaft 76a and the rotation pin 78 in a predetermined rotation direction. Accordingly, the sector gear 79 integrated with the rotation shaft 76a and the like in the rotation direction is rotated by the same amount in the same direction. By the rotation of the sector gear 79, the pinion gear 80 meshed with the gear portion 79a is rotated in the opposite direction by the number of meshed teeth.
[0043]
When the drive pin 81 rotates about the pivot 76c, the drive pin 81 moves along the elongated hole 82c and moves the filter holder 82 in a direction to be pulled out from the filter housing portion 72. Accordingly, the filter holder 82 is guided by the guide portion 75 and moves in the direction orthogonal to the optical axis direction. As a result, the infrared cut filter 91 held by the filter holder 82 is linearly moved in the orthogonal direction from a predetermined position on the optical axis and moves to a predetermined position off the optical axis.
[0044]
On the other hand, when the infrared cut filter 91 is moved from a predetermined position outside the optical axis to a predetermined position on the optical axis, an operation reverse to the above-described retreat operation is performed, thereby moving the infrared cut filter 91 on the optical axis. Can be moved to a predetermined position.
[0045]
The rear end of the fixed ring 15 abuts on the front surface of the rear lens barrel 17A on which the infrared cut filter 91 and the like are mounted, and is fixed and integrated by fixing means such as mounting screws. The rear end of the fixed ring 15 is provided with a plurality of screw receiving portions 15c through which mounting screws are inserted, and the same number of recesses 17a are formed in the rear barrel 17A corresponding to the screw receiving portions 15c. Is provided. The fixed ring 15 is positioned with respect to the rear barrel 17A by fitting the respective screw receiving portions 15c into these concave portions 17a. By screwing in this state, the fixing ring 15 is tightened and fixed to the rear barrel 17A to be integrated.
[0046]
With the above configuration, this collapsible lens can execute the above-described “night shot function” and “night framing function”. That is, when the optical lens is used as an optical lens between the wide state shown in FIG. 10B and the tele state shown in FIG. "Night framing shooting" can be performed.
[0047]
11A and 11B illustrate an operation of putting the infrared cut filter 91 in and out, and FIG. 11A shows a state where the infrared cut filter 91 is set at a predetermined position on the optical axis, and FIG. This shows a state where it is completely moved out of the optical axis. In the same figure, the symbol H indicates the moving direction of the infrared cut filter 91.
[0048]
As a photographing apparatus provided with the retractable optical unit as described above, for example, there is one as disclosed in Japanese Patent Application Laid-Open No. H11-157,036. Patent Document 1 discloses an optical device such as a camera capable of moving an optical system between a use position and a storage position.
[0049]
This optical device is provided behind a first lens unit that forms the optical system, a first motor that drives the first lens unit, and a first lens unit that forms the optical system. A second lens unit, a second motor for driving the second lens unit, and the second lens unit in response to a storage instruction of the optical system, wherein the second lens unit is retracted. After the completion, retraction of the first lens unit is started, and the first and second motors are controlled so that the first lens unit is retracted into a space formed by the retraction of the second lens unit. It has a control means to perform.
[0050]
Further, as an image pickup apparatus provided with an infrared cut filter, for example, there is an image pickup apparatus as disclosed in Japanese Patent Application Laid-Open Publication No. H11-163873. Patent Document 2 discloses an image pickup apparatus having an image pickup device capable of picking up an image in a visible light region and an infrared light region.
[0051]
An image pickup apparatus having an image pickup device capable of picking up an image in a visible light region and an infrared light region, comprising: an infrared light cut filter that can be arranged in an optical path and can be removed from the optical path; A signal processing unit for performing signal processing on an image signal obtained from the element; a detection unit for detecting brightness when the image signal is captured; and determining whether an erroneous operation is performed based on a detection result of the detection unit. And control means for notifying the user of the erroneous operation.
[0052]
[Patent Document 1]
JP-A-2000-194046 (pages 3 to 5, FIG. 1 and the like)
[Patent Document 2]
JP-A-2000-261716 (page 2, FIG. 1)
[0053]
[Problems to be solved by the invention]
However, in the “collapse lens capable of taking a picture at night equipped with a night shot function” as described with reference to FIGS. In addition, there is a problem that the overall length of the lens at the time of collapsing becomes thicker as compared with "a collapsible lens that cannot be photographed at night without a night shot function".
[0054]
4A is a “collapsed lens without a night shot function (hereinafter referred to as“ X type ”), FIG. 4B is a“ collapsed lens according to the prior art with a night shot function (hereinafter referred to as “Y type”) ”, and FIG. 1 shows a collapsible lens according to the present invention having a night shot function (hereinafter referred to as “Z type”).
[0055]
As is clear from FIGS. 4A and 4B, when comparing the X-type retractable lens with the Y-type retractable lens, it became clear that the thickness T1 of the Y-type retractable lens was increased by the thickness of the retracting means 88.
[0056]
SUMMARY An advantage of some aspects of the invention is to provide an optical unit capable of further reducing the thickness of a retractable lens and an imaging apparatus including the optical unit. It is an object.
[0057]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the optical unit of the present application has at least one lens barrel movable along the optical axis direction with respect to the fixed barrel, and has an optical filter behind the lens barrel. The collapsible optical unit is characterized in that a retracting means is provided for moving the optical filter in a direction intersecting the optical axis and retracting the optical filter outside the optical axis when the optical unit is retracted.
[0058]
Further, the imaging apparatus including the optical unit of the present application includes a fixed lens barrel, at least one lens barrel movable along the optical axis direction with respect to the fixed lens barrel, and a lens barrel behind the lens barrel. A digital still camera equipped with a retractable optical unit having an optical filter disposed therein, and a retracting unit for retracting the optical filter in a direction intersecting the optical axis and retracting the optical filter when the optical unit is retracted, It is a camera device such as a video camera.
[0059]
In the above-described optical unit, when the lens barrel is retracted, the optical filter is retracted in a direction intersecting the optical axis, so that the lens frame of the lens barrel enters the retracted space. Therefore, it is possible to reduce the overall length of the collapsible lens of the optical unit, and to reduce the size.
[0060]
Further, in an imaging device including the optical unit of the present application, an optical unit that can be reduced in size can be used, so that the overall size and thickness of the imaging device can be reduced.
[0061]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of a collapsible optical unit and an imaging apparatus including the optical unit according to the present invention will be described below with reference to the drawings.
[0062]
1A, 1B, and 1C are cross-sectional views of a retractable lens according to the present invention. FIG. 1A shows a retracted position where the lens is not used, FIG. 1B shows a wide (wide-angle) position, and FIG. 1C shows a telephoto position. It shows each state of the position. FIG. 2 is an enlarged sectional view of FIG. 1A. FIGS. 3A and 3B are cross-sectional views for explaining the operation of inserting and removing the infrared cut filter.
[0063]
Here, the first group lens frame 10 holding a plurality of lenses 11 and the second group lens frame 13 holding a plurality of lenses 13a are rotated from the retracted position in FIG. 1A to the wide position in FIG. The respective operations when performing the zooming operation of moving from the wide position of 1B to the tele position of FIG. 1C and the reverse wide operation are the same as those described with reference to FIGS. 10A, 10B, and 10C.
[0064]
Also, a feature of the present invention is that, in the collapsed state of the optical unit, the optical filter including the optical low-pass cut filter and the infrared cut filter is retracted in the direction orthogonal to the optical axis L, and the retracted state is achieved. The entire length of the retractable lens can be reduced by inserting a third lens group frame such as a focus lens into the space.
[0065]
Hereinafter, the retracting mechanism of the optical filter will be described with reference to FIGS. 1A to 1C, 2 and 3A and 3B. In FIGS. 1A to 1C, 2 and 3A and 3B, the same components as those described in FIGS. 4A to 4C, FIGS. 8A to 8C, FIG. 9, 10A to 10C, and FIGS. The description is given with the same reference numerals.
[0066]
The collapsible lens (imaging lens unit) 90 according to the present embodiment has substantially the same overall configuration as the collapsible lens of “equipped with a night shot function capable of taking a picture at night” described with reference to FIGS. Therefore, here, the overall configuration will be briefly described, and differences will be described in detail.
[0067]
1A to 1C, reference numeral 10 denotes a first group lens frame that holds a plurality of lenses 11, and reference numeral 12 denotes a cam ring that supports the first group lens frame 10 movably in the optical axis direction. Reference numeral 13 denotes a second group lens frame that holds the plurality of lenses 13a, and reference numeral 16 denotes a straight guide ring that supports the second group lens frame 13 so as to be movable in the optical axis direction. Reference numeral 15 denotes a fixed ring that supports the cam ring 12 so as to be movable in the optical axis direction. The fixed ring 15 is integrally fixed to the front surface of the rear barrel 17.
[0068]
The rear lens barrel 17 holds an optical low-pass cut filter 85 and the solid-state imaging device 24, and a seal rubber 23 is interposed between the two. An infrared cut filter 91, which is a specific example of the optical filter, is disposed in front of the optical low-pass cut filter 85 so as to be linearly movable between on and off the optical axis L. Further, a lens 19 held by the third lens group frame 18B is arranged in front of the infrared cut filter 91 on the optical axis.
[0069]
The third-group lens frame 18B has the same configuration as the above-described third-group lens frame 18, but is downsized in the radial direction as long as the optical performance is not adversely affected, and the infrared cut filter 91 and the filter holder 82 It is preferable that the shape is such that it is easy to retract in the direction orthogonal to the optical axis L. In this case, it is also effective to provide a notch in the third lens frame 18B to avoid the filter holder 82 retracted in the direction orthogonal to the optical axis L.
[0070]
The configuration of the rear barrel 17B is the same as that of the above-described rear barrel 17A, except that the filter holder 82 is retracted in the direction orthogonal to the optical axis L and the third lens group frame 18B is moved in the direction of the solid-state imaging device 24 It is preferable to do the following in order to store the information. First, in order to retreat the filter holder 82 in a direction orthogonal to the optical axis L, the clearance of the retreat opening 74 is made larger than in the related art. Second, the opening 73 is made larger than before because the third lens group frame 18B is stored in a space formed after the filter holder 82 has been retracted in the direction orthogonal to the optical axis L. Usually, the opening 73 may also serve as a function of a fixed stop, but this function can be provided in another opening (for example, a portion where the optical low-pass cut filter 85 is fixed). Therefore, it is possible to increase the size of the opening 73 in terms of design.
[0071]
Next, the operation of the present embodiment will be described. In the state used as an optical lens from the wide state in FIG. 1B to the telephoto state in FIG. 1C, the infrared cutoff filter 91 is moved in and out of the optical axis L so that infrared shooting can be performed and infrared shooting can be performed. (See FIGS. 3A and 3B).
[0072]
In the collapsing operation of the collapsible lens 90, as shown in FIG. 1A, by supplying the power from the power source 76 to the filter holder 82 (arrow J), the infrared cut filter 91 is irradiated with light through the filter holder 82. It can be retracted in a direction perpendicular to the axis L. After that, the third group lens frame 18B is stored in the empty space where the infrared cut filter 91 is retracted in the direction orthogonal to the optical axis L (arrow I). As a result, the third group lens frame 18B is stored at a deeper position than in the related art, and is stored thinner.
[0073]
Further, since the third lens group frame 18B is stored thinner than before, the first lens group frame 10, the second lens group frame 13, and the rectilinear guide ring 16 are superimposed on the empty space along a predetermined cam curve. (Arrows A, B and C).
[0074]
As apparent from FIGS. 4A to 4C in which the relationship between the three types is compared, the total length of the Y-type retractable lens is increased by the thickness T1 of the retracting unit 88, as compared with the X-type retractable lens and the Y-type retractable lens. You can see that. On the other hand, comparing the Y-type collapsible lens with the Z-type collapsible lens, it can be seen that the total length of the Z-type collapsible lens is reduced by the thickness T2 despite the use of both infrared cut filters. Further, comparing the X-type retractable lens with the Z-type retractable lens, the total length of the Z-type retractable lens is reduced by the thickness T3 despite the addition of the infrared cut filter 22.
[0075]
According to the collapsible lens 90 according to the present embodiment, compared to the prior art or the conventional collapsible lens equipped with a night shot function and capable of shooting at night, a storage space is efficiently created and the space is utilized. To accommodate the lens frame (FIGS. 4A to 4C). Therefore, the overall length of the collapsible lens 90 was reduced and the thickness was reduced.
[0076]
Moreover, compared to the conventional collapsible lens that cannot be photographed at night without the night shot function, the infrared cut filter is retracted in the direction perpendicular to the optical axis L to efficiently create a storage space and save the space. Since it is used, the overall length of the collapsible lens 90 can be reduced and the thickness can be reduced.
[0077]
The present invention is not limited to the embodiment described above and shown in the drawings, and various modifications can be made without departing from the scope of the invention.
[0078]
For example, in the above embodiment, the infrared cut filter is retracted in a direction orthogonal to the optical axis. However, the retreat direction does not have to be a direction orthogonal to the optical axis. If the infrared cut filter can be moved in and out of the optical axis so as to function, for example, the infrared cut filter may be moved in an oblique direction, and the present invention is not limited to the direction in which the external cut filter is put in and out. Further, the mechanism for taking in and out the infrared cut filter is not limited to the above-described embodiment.
[0079]
Further, in the above embodiment, the rail-shaped guide portion 75 for allowing the infrared cut filter to be movable in the direction orthogonal to the optical axis is provided in the rear barrel. A drive guide means (for example, a flap method, a turning method, or the like) may be configured, or may be provided in a barrier drive mechanism or the like.
[0080]
Further, the lens configuration of the collapsible lens is not limited to the present embodiment, and the same applies to the driving method of the collapsible lens. As a driving source, not only a stepping motor but also an ultrasonic motor or a general DC motor can be used. Further, a gear unit is not always necessary, and for example, a direct drive by an ultrasonic motor or a linear motor may be used.
[0081]
The retractable structure of the retractable lens is not limited to a cam mechanism using a cam groove or a cam pin, but may be any mechanism that accommodates an optical lens system in a thin shape, such as a ball screw type, a rack and pinion type, and a linear type. Various mechanisms such as a motor type can be adopted.
[0082]
【The invention's effect】
As described above, according to the optical unit of the present application, since the optical filter is retracted in the direction intersecting the optical axis when the lens barrel is retracted, the lens frame of the lens barrel is placed in the retracted space. Therefore, the overall length of the retractable lens of the optical unit can be reduced and the size of the optical unit can be reduced.
[0083]
In addition, according to the imaging apparatus including the optical unit of the present application, since the optical unit that can be reduced in size is used, the imaging apparatus can be used as a camera device such as a digital still camera and a digital video camera, and The effect of reducing the size and thickness can be obtained.
[Brief description of the drawings]
1A and 1B show a retractable lens according to the present invention. FIG. 1A shows a retracted state in which the lens is stored when not in use, FIG. 1B shows a wide (wide angle) state, and FIG. 1C shows a tele (telephoto) state. FIG.
FIG. 2 is an enlarged sectional view of FIG. 1A.
FIGS. 3A and 3B are cross-sectional views illustrating an operation of putting and removing an infrared cut filter according to the present invention, wherein FIG. 3A is a state in which the filter is positioned on the optical axis, and FIG.
FIG. 4 is a comparison of the retracted state of the retractable lens according to the present invention and a conventional retractable lens, wherein FIG. 1A is a retractable lens without a night shot function, FIG. 1B is a conventional retractable lens with a night shot function, FIG. 1C is a sectional view showing a retractable lens according to the present invention having a night shot function.
FIG. 5 is an external perspective view of the digital still camera in which the optical unit is in a collapsed state.
FIG. 6 is an external perspective view of a digital still camera in which an optical unit is extended to a wide state or a tele state.
7A and 7B are external perspective views of the optical unit. FIG. 7A is a perspective view illustrating a collapsed state, FIG. 7B is a perspective view illustrating a wide state, and FIG.
8A and 8B show a conventional retractable lens without a night shot function. FIG. 8A is a sectional view showing a retracted state, FIG. 8B is a sectional view showing a wide state, and FIG.
FIG. 9 is an exploded perspective view showing the collapsible lens of FIG. 8;
10 shows a retractable lens having a night shot function according to the prior art, wherein FIG. 10A is a sectional view showing a retracted state, FIG. 10B is a sectional view showing a wide state, and FIG. 10C is a sectional view showing a telephoto state.
11A and 11B illustrate the operation of putting the infrared cut filter of the collapsible lens having the night shot function shown in FIG. 10 into and out, and FIG. 11A is a state in which the filter is positioned on the optical axis, and FIG. It is sectional drawing which respectively shows.
12 is an exploded perspective view of the retracting means of the infrared cut filter of the collapsible lens having the night shot function shown in FIG. 10 and viewed from the front side.
13 is an exploded perspective view of the retracting means of the infrared cut filter of the collapsible lens having the night shot function shown in FIG. 10 and viewed from the rear side.
[Explanation of symbols]
2, 70, 90: imaging lens unit (collapsed lens), 10: first group lens frame, 10a: cam pin, 12: cam ring, 13: second group lens frame, 15: fixed ring, 16: straight guide ring, 17 , 17A, 17B: rear lens barrel, 18, 18B: 3rd lens frame, 22: optical filter, 24: solid-state imaging device (imaging means), 71: casing, 72: filter housing, 73: opening, 74 ... Evacuation port, 75: guide portion, 76: power source, 82: filter holder, 83: power transmission mechanism, 85: optical low-pass cut filter (optical filter), 86: moving mechanism, 88: evacuation means, 91: infrared region Cut filter (optical filter)

Claims (6)

In a collapsible optical unit having at least one lens barrel movable along the optical axis direction with respect to the fixed barrel, and having an optical filter behind the lens barrel,
An optical unit, comprising: a retracting means for moving the optical filter in a direction intersecting the optical axis and retracting the optical filter outside the optical axis when the optical unit is retracted. The optical unit according to claim 1,
A filter holder provided on the fixed lens barrel and movably holding the optical filter between a position on the optical axis and a position off the optical axis; and the optical holder held by the filter holder. An optical unit, comprising: a moving mechanism for moving the filter between a position on the optical axis and a position off the optical axis. The optical unit according to claim 2,
The moving mechanism includes a filter frame that holds the optical filter, a power source that generates power for moving the filter frame, and a power transmission that transmits the power of the power source to the filter frame and moves the filter frame linearly. An optical unit comprising: a mechanism. The optical unit according to claim 1,
The optical unit, wherein the optical filter is an infrared cut filter and / or a low-pass cut filter. The optical unit according to claim 1,
An optical unit, wherein a lens frame of a focus lens enters a space where the optical filter is retracted. A fixed barrel, at least one lens barrel movable along the optical axis direction with respect to the fixed barrel, an optical filter disposed behind the lens barrel, and a collapsed optical unit A retraction means for moving the optical filter in a direction intersecting the optical axis and retracting the optical filter out of the optical axis, and a camera device such as a digital still camera or a digital video camera equipped with a retractable optical unit having An imaging device characterized by the following.

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