JP2001125187A - Optical equipment system, optical equipment and accessory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that the transmission loss of power is large in the conventional power transmitting method of an electromagnetic induction system. SOLUTION: This optical equipment system is composed of optical equipment 1 and an accessory 9 attachable/detachable to/from the optical equipment, and transmits the power or a signal by the electromagnetic induction between the optical equipment and the accessory. In the system, the optical equipment and the accessory are provided with cores 7a and 13a formed of ferromagnetic material and coils 7c and 13c wound round the cores, and both cores are made to abut on each other when the accessory is attached to optical equipment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device system including an optical device such as a camera and an accessory such as a photographing lens. It is about.

[0002]

2. Description of the Related Art Normally, a power supply system of a camera having a replaceable lens has a structure in which a battery serving as a power supply is mounted on a camera body and a required power is supplied from the camera body to the lens side. At this time, power is transmitted and received via respective connection terminals provided near both mounts that couple the camera body and the lens.

[0005] As described above, when power is supplied by contact, a problem is an increase in contact resistance and leakage due to condensation or rain. An increase in the contact resistance value occurs when the surface of the connection terminal is worn by repeating the lens exchange many times. When the resistance value increases, power transmission is lost, and required power cannot be transmitted. In addition, leaks due to condensation or rain are likely to occur when the camera is used outdoors, and once it occurs, an overcurrent flows through the camera body and the lens circuit.

As a method for solving the above-mentioned problem of power transmission by contact, Japanese Patent Application Laid-Open No. 9-90462 proposes a non-contact power transmission method using the principle of electromagnetic induction. Specifically, an electromotive force is generated by electromagnetic induction in a secondary coil provided in the lens by energizing a primary coil provided in the camera, and this electromotive force is used as a power source on the lens side.

[0005]

However, the power transmission method proposed in the above publication has a problem that the power transmission loss may increase. That is, since the magnetic coupling between the primary side coil and the secondary side coil is performed without passing through the core material, a large amount of leakage magnetic flux may occur, which may cause a considerable transmission loss.

[0006] By the way, even in portable devices other than cameras, a method has been proposed in which electric power is transmitted from a charger having a primary coil or a power transmitter to a portable device having a secondary coil by using electromagnetic induction. .

However, in these proposals regarding portable devices, it is generally assumed that a charger or a power transmitter having a primary coil is used indoors.
It does not consider outdoor use where the environment changes drastically.
On the other hand, in the case of a camera, a camera having a primary coil,
Frequently, both accessories having a secondary coil are taken out and used at the same time outdoors, and it is necessary to improve the environmental resistance of both accessories and to improve the portability (that is, to reduce the size).

[0008]

According to the present invention, there is provided an optical apparatus comprising: an optical device; and an accessory which is detachable from the optical device. In an optical device system for performing power or signal transmission according to the present invention, a core formed of a ferromagnetic material and a coil wound around the core are provided for each of the optical device and the accessory, and the accessory is mounted on the optical device. Then, both cores are brought into contact with each other.

[0009] For example, a magnetically closed circuit is formed by abutting the two cores, and a frequency current is applied to a coil (primary coil) on the optical device side to make a coil (secondary coil) on the accessory side. An electromotive force is generated by electromagnetic induction, and this electromotive force is used as a power source on the accessory side.

This makes it possible to induce an electromotive force in the secondary coil in a state where there is no physical gap between the primary core and the secondary core. Power or signal transmission loss can be almost eliminated.

In the case where the optical device and the accessory are provided with a mount portion which serves as a joint surface with a counterpart when the accessory is mounted on the optical device, the contact surfaces of both cores are mounted. It is preferable to expose the portion. In this case, the contact surfaces of both cores are subjected to rust prevention treatment so that the core contact surfaces are not rusted by moisture or rainwater in the outside air, so that a stable contact state can always be maintained. Is preferred. Further, by forming the mount portion from a non-magnetic material, it becomes possible to confine the magnetic flux in both cores without waste when transmitting power or the like.

Further, the area of the contact surface of the core on the accessory side is made larger than the area of the contact surface of the core on the optical device side, so that the mounting error of each coil, the mechanical error of the mount, the optical device and the accessory It is preferable to eliminate the influence of the relative displacement generated between the primary side coil and the secondary side coil due to the mounting, etc., and to prevent an increase in transmission loss.

When the optical device is a camera body and the accessory is a photographic lens, the core and the coil on the camera body side are arranged along the outer surface of a mirror box in the camera and serve as a joint surface with the photographic lens. It is arranged so that it is almost within the optical axis projection area of the mount part, or the core and coil on the photographing lens side are almost fit within the optical axis direction projection area of the mount part, which is the joint surface with the camera body. Is preferred. Alternatively, the core and the coil on the camera body side and the photographing lens side are arranged such that the circuit plane formed by the magnetically closed circuit is substantially perpendicular to the photographing screen of the camera body and substantially parallel to the side of the photographing screen. Is preferred. Thus, it is possible to reduce the size of the camera body and the photographing lens.

[0014]

1 to 3 show a camera system comprising a camera body (optical device) and a taking lens (accessory) according to an embodiment of the present invention. FIG. 1 shows a state in which the taking lens is detached from the camera body, and FIG. 2 shows a state in which the taking lens is attached to the camera body. FIG. 3 shows a state in which the mount section of the camera body is viewed from the optical axis direction.

In these figures, reference numeral 1 denotes a main body of a single-lens reflex camera (hereinafter, referred to as a camera main body). 1
“a” is a grip formed on the side of the camera body 1. Reference numeral 15 denotes a battery housed in the grip 1a.

Reference numeral 2 denotes a mirror box disposed substantially at the center of the camera body 1. 2a are left and right side walls of the mirror box 2. Reference numeral 3 denotes a mount on the camera body fixed to the mirror box 2 and has an annular shape. Three
Reference numeral a denotes a lens bonding surface formed on the front surface of the mount 3, which is in close contact with a camera bonding surface 10 a formed on the mount 10 of the photographing lens 9 and serves as a mounting reference surface of the photographing lens 9. L is a photographing optical axis.

Reference numeral 3b denotes a mounting claw, and
By rotating the taking lens 9 with respect to the camera body 1 in a state in which the a
The photographing lens 9 is fixed to and detachable from the camera body 1 by engaging and disengaging from the side mounting claw 10b.

Reference numeral 4 denotes a reflection mirror provided inside the mirror box 2 so as to be movable forward and backward with respect to the photographing optical path. 5
Is a pentaprism, which is arranged above the mirror box 2. Photographing lens 9 attached to camera body 1
Is reflected by the reflection mirror 4 and guided to the pentaprism 5, and further passes through the pentaprism 5 to the photographer's eyes except for the viewfinder.

Reference numeral 6 denotes a rectangular shooting screen area on the film surface of the camera body 1, which is indicated by a broken line in the figure. Reference numeral 6a denotes left and right short sides of the photographing screen frame 6. 6b is a long side of the upper and lower sides of the photographing screen frame 6. The left and right short sides 6a and the left and right side walls 2a of the mirror box 2 are substantially parallel.

Reference numeral 7 denotes a primary coil unit for transmitting power. Reference numeral 7a denotes a core made of a ferromagnetic material, which is formed in a U-shape that opens toward the front surface of the camera body 1. 7b is a bobbin mounted on the core 7a. Reference numeral 7c denotes a primary coil wound around the bobbin 7b. The primary coil 7c is wound in a direction parallel to the left and right short sides 6a of the photographing screen 6.

That is, the core 7a and the primary coil 7c
Is the side wall surface 2 of the mirror box 2 as shown in FIG.
a, and are arranged so as to be substantially within the projected area of the mount 3 in the optical axis direction. This enables a space-saving arrangement of the primary side coil unit 7 without taking up unnecessary space in the camera body 1.

Reference numerals 7d and 7e denote end surfaces (contact surfaces) of the U-shaped core 7a. The core end surfaces 7d and 7e are arranged so as to be flush with the joint surface 3a of the mount 3, that is, exposed at the joint surface 3a. The core end faces 7d and 7e have a circular shape having a diameter "r". Further, the core end faces 7d and 7e are plated to a thickness of about several microns for rust prevention treatment. By performing such rust prevention treatment, rust on the core end surfaces 7d and 7e can be prevented without using a thick protective cover made of resin or the like, and a stable surface state can be maintained.

Reference numeral 8 denotes a camera body side optical communication device provided inside the mount 3. The optical transmission unit 8a is the camera body 1
The various information on the side is transmitted to the photographing lens 9 side by optical communication. The light receiving unit 8b receives various information from the photographing lens 9 by optical communication.

Reference numeral 11 denotes an optical system formed in the taking lens 10, and 12 denotes a rear end frame of the taking lens 9. The rear end frame 12 is formed in a rectangular shape in accordance with the photographing screen 6 of the camera body 1. 12a is the left and right short sides of the rear end frame 12,
12b is a long side of the upper and lower sides.

Reference numeral 13 denotes a secondary coil unit for receiving electric power. Reference numeral 13a denotes a core made of a ferromagnetic material, which is formed in a U-shape that opens toward the rear surface of the photographing lens 9. 13b is a bobbin mounted on the core 13b. 13c is a secondary coil wound around the bobbin 13b. The secondary coil 13c is wound in a direction parallel to the short side 12a of the rear end frame 12 of the photographing lens 9. That is, the core 13b and the secondary coil 13
“c” is arranged along the optical path in the photographing lens 9 and is arranged so as to be substantially within the projected area of the mount 10 in the optical axis direction. This enables a space-saving arrangement of the secondary coil unit 13 without taking up unnecessary space in the photographing lens 9.

Reference numerals 13d and 13e denote end surfaces (contact surfaces) of the U-shaped core 13a. These core end faces 13d, 13e
Are arranged so as to be flush with the joint surface 10a of the mount 10, that is, exposed at the joint surface 10a. The core end faces 13d and 13e have a circular shape with a diameter "R".

Here, the diameter "R" of the core end faces 13d and 13e and the core end face 7 on the camera body 1 side described above.
The diameter “r” of d and 7e has a relationship of R> r. That is, the core end face 13 on the secondary side that receives power
The area of d, 13e is changed to the core end face 7 on the primary side for transmitting power.
The area is set to be larger than the areas of d and 7e. As a result, the mounting errors of the coil units 7 and 13 and the mechanical errors of the mounts 3 and 10 or the camera 1 and the photographing lens 9
Even if the primary coil unit 7 and the secondary coil unit 13 are displaced relative to each other due to attachment of the primary coil unit 7 to the primary coil unit 7, the primary Core end surfaces 7d and 7e can be brought into contact, and all of the magnetic flux generated on the primary side can be transmitted to the secondary side without leakage.

The core end faces 13d and 13e are also plated to a thickness of about several microns for rust prevention treatment so that the core end faces 13d and 13e can maintain a stable surface state.

Reference numeral 14 denotes a lens-side optical communication device provided inside the mount 10. Information is transmitted to the light receiving unit 14a from the light transmitting unit 7a of the camera body 1 by optical communication. The light transmitting unit 14b transmits various information to the light receiving unit 8b of the camera body 1 by optical communication.

FIG. 2 also shows an electric circuit configuration in the camera system of the present embodiment. First, the circuit configuration of the camera body 1 will be described. Reference numeral 16 denotes a power supply circuit. The power supply circuit 16 receives a power from the battery 15 to generate a necessary output and supplies it to another circuit. Specifically, the power supply circuit 16 includes a load (circuit) in the camera (not shown).
And a necessary AC voltage or frequency voltage to the primary coil 7c.

Reference numeral 17 denotes a control circuit which receives necessary power from a power supply circuit 16. The control circuit 17 is connected not only to the optical communication device 7, but also to communication with other circuits and to devices such as sensors (not shown). Control the drive sequence.

Next, the circuit configuration of the photographing lens 9 will be described. Reference numeral 18 denotes a lens drive motor, and the optical system 1
By driving No. 1, focus adjustment is performed.

Reference numeral 19 denotes a power supply circuit. This power supply circuit 19
Is connected to a secondary coil 13c, and supplies a part of electric power supplied from the camera body 1 side to the lens drive motor 18 via the secondary coil 13c as described later.

Reference numeral 20 denotes a control circuit. This control circuit 20
The optical communication device 14 is connected to the, and communicates with other circuits, and controls a lens-side drive sequence in accordance with an output from a device such as a sensor (not shown).

Reference numeral 21 denotes a secondary battery, which can store electric power supplied from the camera body 1 side. Further, when the capacity of the battery 15 on the camera main body 1 side becomes equal to or less than a predetermined value, it is also possible to supply power from the secondary battery 21 to the camera main body 1 side. In this case, the coil unit 13 on the lens side is the primary coil unit, the camera body 1
Side coil unit 7 becomes the secondary side coil unit,
The power supply relationship is reversed.

In the camera system described above, when the camera body 1 and the photographing lens 9 are joined together with the joint surfaces 3a and 10a of the mounts 3 and 10 in close contact with each other, the core end surfaces 7d and 7e on the camera body 1 side and the lens The core end faces 13d and 13e on the side are in close contact with each other, and a magnetically closed circuit is formed. The circuit plane formed by the magnetically closed circuit is substantially perpendicular to the photographing screen frame 6 of the camera body 1 and the photographing screen 6
Is substantially parallel to the short side 6a.

In the above-described state, the power generated by the power supply circuit 16 on the camera body 1 is first transmitted to the primary coil 7c as an alternating current or a frequency signal having a predetermined frequency, whereby the primary coil 7c is transmitted to the primary coil 7c. A magnetic field is generated.
Since a magnetically closed circuit is formed by the core 7b and the core 13b, a voltage is induced in the secondary coil 13c by the principle of electromagnetic induction.

Since the voltage induced in the secondary coil 13c is an alternating current, the waveform is shaped by the power supply circuit 19 on the taking lens 9 side to be a direct current, and then supplied to a load such as the lens drive motor 18. .

Here, a boundary plane P exists between the primary coil unit 7 and the secondary coil unit 13,
Since the primary and secondary core end faces are in close contact with each other, the gap between the primary coil unit and the secondary coil unit is limited by the plating thickness applied to each core end face for rust prevention treatment. Since it is on the order of a few microns, there is almost no power transmission loss due to this gap.

On the other hand, when the photographing lens 9 is not mounted on the camera body 1, communication between the camera body side optical communication device 8 and the lens side optical communication device 14 becomes impossible, and it is determined that the camera body 1 is not mounted. You. At this time, power is not supplied from the power supply circuit 16 to the primary side coil 7c by the control circuit 17 of the camera body 1, so that safety is ensured and there is no wasteful power consumption, which is economical. .

In this embodiment, both the primary coil unit 7 and the secondary coil unit 13 are arranged so as to be substantially parallel to the short side 6a of the photographing screen frame 6 of the camera body 1. Space can be saved even if it is arranged so as to be substantially parallel to the long side 6b.

In this embodiment, the camera body 1
Although the case where the primary coil unit 7 for one photographing lens is provided has been described, a plurality of primary coil units may be provided in correspondence with various camera accessories having different power supply specifications.

In the present embodiment, power is transmitted from the camera 1 to the photographing lens 9 (or from the photographing lens 9 to the camera 1) via the coil units 7 and 13, and signal transmission other than power transmission is performed by the optical communication device 8 , And 14, the information may be transmitted between the camera and the taking lens using the same coil unit.

Further, in the present embodiment, the cores 7a, 13
a is fixed to the camera body 1 and the photographing lens 13 respectively, and each core end face is
Although the case where the same surfaces as those a and 10a are formed has been described, both cores are urged toward the camera and the photographic lens by a spring or the like in the contact direction with the opposing core to separate the camera and the photographic lens. Alternatively, each core end surface may slightly protrude from the joint surface of the mount. Thus, even if each coil unit has an installation error in the optical axis direction, both cores can be securely brought into close contact with each other when the photographing lens is mounted on the camera.

In the above embodiment, a camera system comprising a so-called silver halide camera body and a photographing lens has been described. However, the present invention relates to a camera system comprising a digital camera or a video camera and a photographing lens, and the like. Can be applied to the optical device system of
For example, in a camera system including a camera body and an external flash device (accessory), the flash device side on which a large number of batteries can be mounted may be used as a power supply source for the camera body side.

[0046]

As described above, according to the present invention,
When the accessory is mounted on the optical device, the core on the optical device and the core on the accessory side are brought into contact with each other, so that there is a physical gap between the core on the optical device and the core on the accessory side. As a result, transmission loss of power or the like from the optical device side to the accessory side can be almost eliminated.

Also, by applying a rust-preventive treatment to the contact surface of the core exposed on the mount portion or the like, the core contact surface is not rusted by moisture or rainwater in the outside air, and is always in a stable contact state. Can be maintained.

Further, by forming the mount portion from a non-magnetic material, magnetic flux can be confined in both cores without waste when transmitting electric power or the like.

Furthermore, if the area of the contact surface of the core on the accessory side is made larger than the area of the contact surface of the core on the optical device side, the mounting error of each core, the mechanical error of the mount, the optical device and the accessory It is possible to eliminate the influence of the relative displacement between the two cores due to the mounting of the core and the like, thereby preventing an increase in transmission loss.

When the optical device is a camera body and the accessory is a photographing lens, the core and the coil on the camera body side are arranged along the outer surface of the mirror box in the camera body and serve as a joint surface with the photographing lens. It is arranged so that it is almost within the optical axis projection area of the mount part, or the core and coil on the photographing lens side are almost fit within the optical axis direction projection area of the mount part, which is the joint surface with the camera body. Or the core and coil of the camera body and the photographic lens are arranged so that the circuit plane formed by the magnetically closed circuit is substantially perpendicular to the photographic screen of the camera body and substantially parallel to the side of the photographic screen. Then, the size of the camera body and the photographing lens can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view in a state where a camera body and a photographing lens according to an embodiment of the present invention are not mounted.

FIG. 2 is a schematic configuration diagram showing a connection state between the camera body and a photographing lens.

FIG. 3 is a front view of the periphery of a mount section of the camera body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Camera main body 2 Mirror box 3, 10 mount 6 Imaging screen frame 7, 13 Coil unit 7a, 13a Core 7c, 13c Coil 9 Imaging lens 15 Battery 16, 19 Power supply circuit 17, 20 Control circuit

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tetsuya Nishio 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H044 AE07 AJ05 AJ06 BE02 2H100 DD06 DD11 DD13 2H101 EE08 EE14 EE33 EE43 EE45 EE75 EE83

Claims (15)

[Claims] 1. An optical device system comprising: an optical device; and an accessory detachable from the optical device, and transmitting power or a signal by electromagnetic induction between the optical device and the accessory. And a core formed of a ferromagnetic material and a coil wound around the core are provided for each of the accessories, and the two cores are brought into contact with each other when the accessory is mounted on the optical device. An optical device system characterized by the above. 2. The optical apparatus system according to claim 1, wherein a magnetically closed circuit is formed by bringing the cores into contact with each other. 3. The method according to claim 1, wherein a frequency current is applied to one of the coils of the optical device and the accessory to generate an electromotive force by electromagnetic induction in the other coil, and the electromotive force is used as a power supply. The optical device system according to claim 1. 4. The optical device and the accessory each have a mount portion serving as a joint surface with a counterpart when the accessory is mounted on the optical device, and a contact surface between the two cores is provided. The optical device system according to claim 1, wherein the optical device system is exposed at each of the mount portions. 5. The optical device system according to claim 1, wherein said mount portions are formed of a non-magnetic material. 6. The optical device system according to claim 4, wherein a rust prevention treatment is applied to a contact surface between the two cores. 7. The optical device according to claim 1, wherein an area of an abutting surface of the accessory-side core is larger than an area of an abutting surface of the optical device-side core. Equipment system. 8. The optical device system according to claim 1, wherein the optical device is a camera body. 9. The optical device system according to claim 8, wherein the accessory is a taking lens. 10. A core and a coil on the camera body side are arranged along an outer surface of a mirror box in the camera body and substantially fit within a projection area in a direction of an optical axis of a mount portion serving as a joint surface with the accessory. The optical apparatus system according to claim 9, wherein: 11. The image pickup apparatus according to claim 9, wherein the core and the coil on the photographing lens side are arranged so as to be substantially contained within a projection area in an optical axis direction of a mount portion serving as a joint surface with the camera body. Or the optical apparatus system according to 10. 12. A magnetically closed circuit is formed by abutting the two cores with each other, and a core and a coil on the camera body side and the photographing lens side each have a circuit plane formed by the magnetically closed circuit, and the camera body is formed by the camera body. The optical apparatus system according to any one of claims 9 to 11, wherein the optical apparatus system is disposed so as to be substantially perpendicular to the photographing screen and substantially parallel to a side of the photographing screen. 13. At least one of the two cores is:
The optical device system according to claim 1, wherein the optical device system is urged in a contact direction with the other. 14. An optical device comprising a core and a coil for constituting the optical device system according to claim 1. Description: 15. An accessory comprising a core and a coil for constituting the optical apparatus system according to claim 1. Description: