JP2011065059A - Lens device and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily perform zoom imaging in an enlargement imaging mode without causing upsizing of a lens device. <P>SOLUTION: The lens device includes a photographic optical system including a plurality of lens units L1 to L4, and zoom mechanisms 5 and 9 changing magnification of the photographic optical system by moving at least some of the plurality of lens units in an optical axis direction. The lens device has an ordinary imaging mode in which magnification is changed between a telephoto end and a wide end, and the enlargement imaging mode in which enlargement imaging is performed at a subject distance shorter than in the ordinary imaging mode. The zoom mechanism changes the magnification continuously from the wide end in the enlargement imaging mode. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a lens apparatus and an imaging apparatus capable of imaging at a high magnification.

An imaging apparatus such as a digital still camera or a video camera often has a zoom function, but a general-purpose imaging apparatus cannot obtain a high-magnification enlarged image of several hundred times.

  On the other hand, for the purpose of magnifying and observing the surface of a material or substance, there have been proposed imaging devices that can be added with dedicated imaging devices or magnification adapters.

  Patent Document 1 discloses an enlargement adapter that has an auxiliary lens having an enlargement magnification and enlarges a subject image to enter the image pickup apparatus.

Japanese Patent No. 3981376

However, when the magnifying adapter disclosed in Patent Document 1 is attached to the imaging device, the entire length of the imaging device including the magnifying adapter increases, making it difficult to handle the imaging device.

In order to capture a magnified image clearly, it is necessary to illuminate the subject brightly. However, the magnifying adapter disclosed in Patent Document 1 has an illumination unit provided behind the auxiliary lens. For this reason, the illumination efficiency of illumination light is low, and it cannot be expected to illuminate the subject brightly. Increasing the light emission luminance of the lighting unit or increasing the light utilization efficiency causes problems such as complication and increase in size of the lighting unit and increase in power consumption.
A first object of the present invention is to provide a lens apparatus and an imaging apparatus that can easily perform zoom imaging in an enlarged imaging mode without increasing the size.

  Furthermore, the present invention provides a lens apparatus and an imaging apparatus, wherein the object can be imaged while illuminating the subject brightly without increasing the complexity or size of the illumination unit and increasing the power consumption. Objective.

A lens apparatus according to an aspect of the present invention includes a photographing optical system including a plurality of lens units, and a zoom mechanism that changes the magnification of the photographing optical system by moving at least a part of the plurality of lens units in the optical axis direction. And have. The lens apparatus has a normal imaging mode in which the magnification is changed between the telephoto end and the wide end, and an enlarged imaging mode in which enlarged imaging is performed at a subject distance shorter than the normal imaging mode. The zoom mechanism is characterized in that the magnification is continuously changed from the wide end in the enlarged imaging mode.
Note that an illumination unit in which a plurality of light emitters are arranged in the direction around the optical axis of the photographing optical system may be disposed closer to the subject than the photographing optical system.

  An imaging device having the lens device and an imaging device that photoelectrically converts a subject image formed by the imaging optical system also constitutes another aspect of the present invention.

According to the present invention, zoom imaging in the enlarged imaging mode can be easily performed without increasing the size of the lens device or the imaging device. In addition, it is possible to take an image while brightly illuminating the subject without complicating or increasing the size of the illumination unit or increasing the power consumption.

1 is a cross-sectional view illustrating a configuration of a camera system that is an embodiment of the present invention. Sectional drawing which shows the modification of the camera system shown in FIG. The rear view which shows the mount provided in the lens-barrel unit in an Example. The front view which shows the structure of the illumination unit provided in the lens-barrel unit in an Example. The block diagram which shows the electric circuit structure of the camera system of an Example. The flowchart which shows the control processing of the illumination unit performed with the camera system of an Example. Sectional drawing which shows the structure of the lens-barrel unit in an Example. The figure which shows the cam curve of the lens-barrel unit in an Example. The figure which shows the zoom area | region in the lens-barrel unit in an Example.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a cross-section when the camera system according to the embodiment of the present invention is cut along a plane including the optical axis. The camera system (imaging device) includes a lens barrel unit 2 as a lens device and a camera body 1 to which the lens barrel unit 2 is detachably mounted.

  In the lens barrel unit 2, a photographing optical system for forming a subject image on the image sensor 3 disposed inside the camera body 1 is provided. The imaging element 3 is configured by a photoelectric conversion element such as a CCD sensor or a CMOS sensor.

The photographic optical system includes a first lens unit L1, a second lens unit L2, a third lens unit L3, and a fourth lens unit L4 in order from the subject side (object side). The first lens unit L1, the second lens unit L2, the third lens unit L3, and the fourth lens unit L4 have positive power (refractive power), negative power, positive power, and positive power, respectively. Note that the photographing optical system includes a diaphragm (not shown) for adjusting the amount of light.
The lens barrel unit 2 has a zoom operation ring 5 that is rotated (manually operated) by a user for a zoom operation for changing the focal length (magnification) of the photographing optical system. A zoom motor is provided in the lens barrel unit 2, and the zoom motor is operated in accordance with an operation of a zoom switch (see 53 in FIG. 5) provided in the camera body 1, and the zoom operation ring 5 is rotated by the zoom motor. You may make it make it.
Further, the illumination unit 13 in which a plurality of LED light emitters 4 are provided on a ring-shaped pedestal 10 at the most object side portion (front end) of the lens barrel unit 2, that is, at the object side from the photographing optical system. However, it is detachably mounted by screwing or using a stopper.
The illumination unit 13 illuminates a subject when the subject is magnified and taken close-up in a microscope mode (in other words, an enlarged imaging mode or a macro imaging mode) described later. On the other hand, in a normal image capturing mode (hereinafter referred to as a camera mode) for capturing a landscape or a person, the lens unit 2 is detached. The illumination unit 13 is movable in the optical axis direction according to a zoom operation.

A hood 14 is detachably attached to the outer periphery of the front end of the barrel unit 2 to prevent external light from entering the photographing optical system. By attaching the illumination unit 13 to the inside of the hood 14, the hood 14 and the illumination unit 13 can be integrally attached to and detached from the lens barrel unit 2.
The hood 14 moves in the optical axis direction in conjunction with the rotation of the zoom operation ring 5 in the microscope mode. This will be described later.
The cam cylinder 9 is connected to the zoom operation ring 5 and rotates around the optical axis with respect to the fixed cylinder 2 a of the lens barrel unit 2 together with the zoom operation ring 5.
Cam grooves 12a to 12d shown in FIGS. 8A, 8B, and 8C are formed in the cam cylinder 9. FIG. A cam follower 8a attached to the first lens barrel 21 holding the first lens unit L1 is engaged with the cam groove 12a, and a second lens barrel 22 holding the second lens unit L2 is engaged with the cam groove 12b. The attached cam follower 8b is engaged. Further, the cam follower 8c attached to the third holding frame 23 holding the third lens unit L3 is engaged with the cam groove 12c, and the fourth holding frame holding the fourth lens unit L4 is engaged with the cam groove 12d. The cam follower 8d attached to 24 is engaged.
When the cam cylinder 9 rotates, the first to fourth lens units L1 to L4 are moved in the optical axis direction by moving the respective cam followers by the cam grooves 12a to 12d, thereby changing the magnification of the photographing optical system. Is done. The zoom operation ring 5 and the cam cylinder 9 constitute a zoom mechanism. In this embodiment, the case where all the first to fourth lens units L1 to L4 are moved in the optical axis direction by the rotation of the cam cylinder 9 and the magnification is changed will be described. It is only necessary that at least a part of the units L1 to L4 move in the optical axis direction to change the magnification.
The lens barrel unit 2 of the present embodiment has a camera mode in which zooming is performed between the wide end and the telephoto end, and a microscope mode in which zooming is performed between the wide end (minimum magnification end) and the maximum magnification end. The microscope mode can perform enlarged imaging at a shorter subject distance than the camera mode.
A mount 6 shown in FIG. 3 is provided on the most camera-side portion (rear end portion) of the barrel unit 2. The lens barrel unit 2 is detachably attached to the camera body 1 by bayonet coupling the mount 6 to a mount (not shown) provided in the camera body 1.
A plurality of electrical contacts 6 a are provided on the mount 6, and power is supplied from the camera body 1 to the LED light emitter 4 of the illumination unit 13 through the electrical contacts 6 a and the internal wiring of the barrel unit 2. As shown in FIG. 2, it is also possible to provide a dedicated power supply contact 7 on the camera body 1 and supply power to the LED light emitter 4 of the illumination unit 13 via the cable 11. Moreover, it is also possible to supply electric power to the LED light emitter 4 through a cable from an interface (not shown) (for example, a USB terminal) provided in the camera body 1.
FIG. 4 shows the illumination unit 13 viewed from the subject side. The illumination unit 13 includes a ring-shaped pedestal 10 and LED light emitters 4 arranged at a plurality of locations (a plurality of locations around the optical axis of the photographing optical system) over the entire circumference of the pedestal 10. FIG. 4 shows an example in which W (white) LED emitters are arranged between R (red), G (green), and B (blue) LED emitters. However, this is an example, and the arrangement of the LED light emitters of each color may be other than this.

By operating an LED selection switch (52 in FIG. 5) provided on the camera body 1, it is possible to selectively emit LED light emitters of any color. As a result, the subject can be imaged with the color partially highlighted. For example, when the subject in the microscope mode is human skin, the subcutaneous tissue can be made to stand out by causing the R-color LED light emitter to emit light. In this case, by providing a polarizing filter at the front end of the barrel unit 2, light reflected from the surface of the skin can be blocked and the subcutaneous tissue can be imaged more clearly.
4 shows a case where the LED light emitters 4 are arranged in a row in the circumferential direction of the pedestal 10, but the LED light emitters 4 may be arranged in a plurality of rows in the circumferential direction of the pedestal 10. Good.
In the case of arranging in two rows, if the irradiation direction of the LED emitters in the inner row is parallel to the normal direction of the lens, it is possible to take an image of the reflected light from a deep place. In addition, by making the irradiation direction of the LED emitters in the outer row oblique to the normal direction of the lens, it is possible to take an image of reflected light from the surface of the subject. In particular, the shadow on the surface can be imaged by the light from the LED emitters in the outer row, and a stereoscopic image can be obtained.
In this way, a desired image can be taken by selecting the row and color of the LED light emitters to emit light.
If the illuminance is inadequate when the maximum magnification in the microscope mode is selected, select all the W LED light emitters in all rows and light them up, so that sufficient illuminance can be obtained for subjects in a narrow field of view. Can be given.

  In the microscope mode, an LED illuminator that emits light may be automatically selected according to the rotation position (that is, magnification) of the zoom operation ring 5. For example, the number of LED light emitters that emit light may increase as the magnification increases, so that the amount of illumination light increases and the subject is brightly illuminated. Note that the amount of illumination light can be changed by changing the voltage applied to the LED emitter. Further, the emission color (illumination color) may be switched according to the magnification so that an image of a tissue under the skin such as a subcutaneous blood vessel can be clearly captured.

FIG. 5 shows an electrical configuration of the camera system of the present embodiment. Here, an electrical configuration when the zoom operation ring 5 and the cam barrel 9 are driven by the zoom motor 65 is shown.
The image sensor 3 photoelectrically converts a subject image formed by the photographing optical system (the first to fourth lens units L1 to L4 and the diaphragm) and outputs an imaging signal. Reference numeral 59 denotes an A / D converter that converts an image signal (analog signal) output from the image sensor 3 into a digital signal. An image processing circuit 58 generates an image by performing various image processing on the digital image pickup signal output from the A / D converter 59.
A camera control unit 56 controls the operation of each unit of the camera body 1. The camera control unit 56 controls the zoom motor 65 and a diaphragm (not shown) through a lens system control unit 61 provided in the lens barrel unit 2.
52 is the LED selection switch described above, and 53 is the zoom switch described above. Reference numeral 60 denotes an imaging switch for performing an imaging operation (image recording operation). Reference numeral 54 denotes a display that is configured by an LCD or the like and displays an image generated by the image processing circuit 18 and other information. Reference numeral 55 denotes an interface between the camera control unit 56, the LED selection switch 52, the zoom switch 53, the imaging switch 60, and the display 54. A memory 57 stores an image generated by the image processing circuit 58 and other information.
When the zoom switch 53 is operated, the zoom motor is driven according to the operation time, the zoom operation ring 5 and the cam cylinder 9 are rotated via a drive transmission mechanism (not shown), and the position of each lens unit is controlled. The Thereby, the magnification of the photographing optical system in the camera mode and the microscope mode changes. These modes can also be selected by an operation not shown.
In the microscope mode, the time from when the zoom switch 53 is operated until the operation is canceled (the operation time and the magnification are associated with each other) or the zoom detected by a rotational position detector (not shown). Information on the rotational position of the operation ring 5 or the cam barrel 9 (that is, the magnification of the photographing optical system) is input to the camera control unit 56. The camera control unit 56 selects the LED light emitter 4 that emits light in the illumination unit 13 according to the operation time of the zoom switch 53 or the information on the rotation position of the zoom operation ring 5. Thereby, the following subject illumination suitable for the magnification of the photographing optical system is performed in the microscope mode.
Reference numeral 51 denotes an illumination control unit. When there is an LED selection instruction from the LED selection switch 52 in advance, the illumination control unit 51 turns on (lights) the LED light emitter 4 in response to receiving an illumination control signal from the camera control unit 56 in the microscope mode. / OFF and light emission color selection control. Each of the R, G, B, and W LED emitters may be caused to emit light alone, or for example, the R and G LED emitters may be lit to perform yellow illumination.
If the relationship between the magnification and the illumination condition (for example, light amount) is stored in the memory 57 in advance as a table, the camera control unit 56 corresponds to the magnification at that time according to the magnification in the zoom operation in the microscope mode. Based on the illumination light quantity stored in the memory 57, the illumination light quantity is adjusted via the illumination control unit 51. The adjustment of the amount of illumination light may be performed, for example, by turning on the ten LED light emitters 4 when the zoom magnification is high, and turning on the five LED light emitters 4 when the zoom magnification is low. . Note that the magnification information in this case is obtained by detecting the rotation positions of the zoom operation ring 5 and the cam barrel 9 as described above.
Further, the camera control unit 56 can determine from the position information of each lens unit obtained from the zoom operation ring 5 or the cam cylinder 9 or the zoom switch 53 that the camera mode has been changed to the microscope mode and vice versa. Based on this, ON / OFF of the LED light emitter 4 can be controlled through the illumination control unit 51. With this configuration, the LED light-emitting body 4 can be turned on when the camera mode is switched to the microscope mode without being turned on in the camera mode, and can be turned off in the opposite case.

  In the present embodiment, the case where the LED selection switch 52 and the zoom switch 53 are provided in the camera body 1 is described. However, these functions may be provided in the lens barrel unit 2.

  Next, control processing of the illumination unit 2 in the camera system of the present embodiment will be described using the flowchart of FIG.

First, in step S61, the camera control unit 56 determines whether or not the imaging switch 60 has been operated, that is, whether or not there has been an imaging instruction from the user. If there is no imaging instruction, the determination in step S61 is repeated, and if there is an imaging instruction, the process proceeds to step S62.
In step S62, the camera control unit 56 determines whether or not the zoom operation ring 5 or the zoom switch 53 has been operated, that is, whether or not there has been a zoom instruction from the user. If there is no zoom instruction, the determination in step S62 is repeated, and if there is a zoom instruction, the process proceeds to step S63.
In step S <b> 63, the camera control unit 56 determines whether or not the illumination condition corresponding to the zoom instruction is stored in the memory 57 in advance. The illumination condition corresponding to the zoom instruction is, for example, LED light emission that emits light when the illumination unit 13 (LED light emitter 4) is turned on when the camera mode is switched to the microscope mode, or when a low magnification zoom instruction is issued. The condition is that the body 4 is limited to reduce the amount of illumination light. If such illumination conditions are not stored, the present control process is terminated, and if stored, the process proceeds to step S64.
In step S64, the camera control unit 56 turns on the illumination unit 13 (LED light emitter 4) or adjusts the amount of illumination light through the illumination control unit 51 according to the illumination conditions.
In the next step S65, the camera control unit 56 determines whether or not the zoom instruction obtained in step S62 is a zoom instruction in the microscope mode. If the zoom instruction is not in the microscope mode, the control process is terminated. If the zoom instruction is in the microscope mode, the process proceeds to step S66.
In step S <b> 66, the camera control unit 56 determines whether there is a selection instruction from the LED selection switch 52. When there is no selection instruction, this control process is terminated, and when there is a selection instruction, the process proceeds to step S67.

In step S <b> 67, the camera control unit 56 turns on the LED light emitters 4 of the color or number corresponding to the selection instruction from the LED selection switch 52 through the illumination control unit 51. Then, this control process ends.
FIG. 7 shows the first to fourth lens units L <b> 1 to L <b> 1 at the (a) tele end in the camera mode, (b) the wide end in the camera mode, and (c) the maximum magnification end in the microscope mode. The positional relationship of L4 is shown.

In the camera mode, zooming is performed by moving the second to fourth lens units L2 to L4 in the optical axis direction from the wide end to the tele end. Further, focus adjustment is performed by the first lens unit L1 moving in the optical axis direction. This focus adjustment can be performed by moving the first lens barrel unit 21 back and forth through a gripping portion (not shown) without moving the zoom operation ring 5. The same applies to the microscope mode.
In zooming in the camera mode, the total length of the lens barrel unit 2 in the optical axis direction does not change.
Also in the microscope mode, zooming is performed by moving the first to fourth lens units L1 to L4 in the optical axis direction between the wide end (minimum magnification end) and the maximum magnification end. However, in zooming in the microscope mode, the lens barrel unit 2 extends toward the subject side from the minimum magnification end toward the maximum magnification end.
In this embodiment, the camera mode and the microscope mode can be switched by operating the zoom operation ring 5 or the zoom switch 53. Accordingly, it is possible to easily perform from normal imaging such as landscape imaging or person imaging in the camera mode to close-up enlarged imaging (macro imaging or microscope imaging) in the microscope mode.

FIG. 8 shows (a) a cam groove 5 a formed in the zoom operation ring 5, (b) a cam groove 12 a formed in the outer peripheral surface of the cam cylinder 9, and (c) an inner peripheral surface of the cam cylinder 9. The specific shape (cam curve) of the formed cam grooves 12b to 12d is shown.
A cam follower provided in the hood 14 is engaged with the cam groove 5 a formed in the zoom operation ring 5. The cam groove 5a does not move the hood 14 in the optical axis direction between the wide end W and the tele end T in the camera mode, and moves the hood 14 toward the subject side from the minimum magnification end W toward the maximum magnification end M in the microscope mode. It is formed so that it is moved (however, immediately before the maximum magnification end M, once moved slightly to the opposite side of the subject and then moved again to the subject).
As described above, the cam follower 8 a provided in the first lens barrel 21 is engaged with the cam groove 12 a of the cam tube 9. The cam groove 12a does not move the first lens barrel 21 (first lens unit L1) in the optical axis direction between the wide end W and the tele end T in the camera mode, and from the minimum magnification end W to the maximum magnification end in the microscope mode. The first lens barrel 21 is formed to move toward the subject side toward M.
As described above, the cam followers 8b to 8d of the second lens barrel 22, the third holding frame 23, and the fourth holding frame 24 of FIG. 1 are engaged with the cam grooves 12b to 12d of the cam barrel 9, respectively. The cam grooves 12b to 12d are formed between the second lens barrel 22 (second lens unit L2) between the wide end W and the tele end T in the camera mode and between the minimum magnification end W and the maximum magnification end M in the microscope mode. The third holding frame 23 (third lens unit L3) and the fourth holding frame 24 (fourth lens unit L4) are formed to move in the optical axis direction. Note that the cam grooves and followers for the third and fourth lens units L3 and L4 are each configured to be double. Further, as can be seen from the positional relationship at the wide end W, for example, the positional relationship of the cam followers corresponding to the respective cam grooves is shifted relative to the rotational direction.

Thus, the cam groove is continuous so that the operation in the microscope mode can be performed on the extension of the camera mode. In addition, the cam grooves for the third and fourth lens units L3 and L4 are symmetrical with respect to the wide end W. Therefore, in the microscope mode, the magnification is increased by moving the third and fourth lens units L3 and L4 in the same direction (subject direction) as the moving direction on the optical axis from the wide end to the tele end in the camera mode. Increase. In synchronism with this movement, the first lens unit L1 also moves in the same direction on the optical axis and approaches the subject.
In the microscope mode, when a zoom operation is performed through the zoom operation ring 5, a lens using a zoom mechanism is used so that the magnification can be changed while maintaining the positional relationship between the subject and the camera body 1 (image pickup device 3). It is also possible to adopt a unit moving configuration. Thereby, enlarged photographing can be performed with the camera body 1 fixed by a tripod or the like.
FIG. 9 shows the imaging range (zoomable range) in the camera mode and the microscope mode of the barrel unit 2 of the present embodiment. The vertical axis represents the subject distance, and the horizontal axis represents the focal length and the magnification. The hatched area indicates the imageable range. However, FIG. 9 is only an example showing the imageable range, and the imageable range of the lens apparatus of the present invention is not limited to this.
As shown in the figure, the lens barrel unit 2 can change the magnification by 5 times from the wide end to the tele end in the camera mode. On the other hand, in the microscope mode, it is possible to take an image at a subject distance shorter than that in the camera mode and continuously from 0.1 times (minimum magnification end) to 3 times (maximum magnification end) obtained at the wide end. The magnification can be changed.
In this embodiment, the work distance WD, which is the distance between the subject and the lens front end, can be increased to some extent even at the maximum magnification end in the microscope mode. Moreover, the depth of focus (depth of field) in the microscope mode is secured to some extent. Thereby, a three-dimensional object can be easily observed even at the maximum magnification end.
As described above, according to the present embodiment, zoom imaging in the microscope mode can be easily performed without increasing the size of the camera system (particularly the lens barrel unit 2). In particular, the transition from the camera mode to the microscope mode can be performed seamlessly, and the operation for the transition is simple.
Further, since the illumination unit 13 is disposed at the front end of the lens barrel unit 2 (subject side with respect to the first lens unit L1), the illumination unit 13 is not complicated, increased in size, or increased in power consumption. Microscopic imaging can be performed while brightly illuminating the subject.
Each embodiment described above is only a representative example, and various modifications and changes can be made to each embodiment in carrying out the present invention.
In this embodiment, the case where the lens apparatus is attached to and detached from the imaging apparatus will be described. However, the present invention can also be applied to an imaging apparatus in which the lens apparatus is provided integrally.

  It is possible to provide a lens apparatus and an imaging apparatus that can perform zooming during normal imaging and also perform zooming during enlarged imaging.

DESCRIPTION OF SYMBOLS 1 Camera main body 2 Lens barrel unit 3 Image pick-up element 4 LED light-emitting body 5 Zoom operation ring 9 Cam cylinder 13 Illumination unit 14 Hood L1-L4 Lens unit

Claims (8)

A lens apparatus having a photographing optical system including a plurality of lens units, and a zoom mechanism for changing a magnification of the photographing optical system by moving at least a part of the plurality of lens units in an optical axis direction;
The lens apparatus has a normal imaging mode in which the magnification is changed between a tele end and a wide end, and an enlarged imaging mode in which enlarged imaging is performed at a subject distance shorter than the normal imaging mode,
The zoom mechanism continuously changes the magnification from the wide end in the enlarged imaging mode.   2. The lens apparatus according to claim 1, wherein in the enlarged imaging mode, the magnification is changed by moving a subject-side lens unit that does not move in the normal imaging mode in the optical axis direction.   2. The lens apparatus according to claim 1, wherein in the enlargement imaging mode, focus adjustment is performed by moving a lens unit on a subject side in an optical axis direction without moving another lens unit. 2. The zoom mechanism according to claim 1, wherein the zoom mechanism increases the magnification by moving a specific lens unit from the wide end in the same optical axis direction as the movement direction for increasing the magnification in the normal photographing mode. Or the lens apparatus of 2   The lens apparatus according to claim 1, further comprising: an illumination unit provided on a subject side with respect to the photographing optical system, wherein a plurality of light emitters are arranged in a direction around an optical axis of the photographing optical system.   The lens apparatus according to claim 2, further comprising a control unit that turns on the illumination unit in response to switching from the normal imaging mode to the enlarged imaging mode.   The lens apparatus according to claim 3, wherein the control unit changes at least one of an illumination light amount and an illumination color of the illumination unit according to the magnification in the enlarged imaging mode. The lens device according to any one of claims 1 to 7,
An image pickup apparatus comprising: an image pickup device that photoelectrically converts a subject image formed by the photographing optical system.