JPH0617968B2 - Shooting optical system lens barrel - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel of a photographing optical system to be mounted on an interchangeable lens type camera, and in particular, it is characterized by improving electrical connection with a camera body side. The present invention relates to a lens barrel of a photographing optical system.

[Background of the Invention] Recent cameras are becoming more automated and equipped with an automatic exposure control device, an automatic focusing device, an automatic light control device, etc., so that various electronic circuits, motors, batteries, etc. are installed in the camera. There is.

In the interchangeable lens type camera equipped with the various devices as described above, since the motor and the electronic circuit are mounted not only on the camera body side but also on the photographing optical system lens barrel side, the camera body and the lens are separated from each other. The mount portion for connection is provided with electrical contacts or connection terminals for electrically connecting various devices in the camera body and various devices in the photographing optical system lens barrel to each other.

In the conventional lens-interchangeable camera, in order to reduce the number of connection terminals, the grounding wire and its connecting terminal of the photographing optical system lens barrel side motor and the grounding wire and its connecting terminal of the photographing optical system lens barrel side electronic circuit are shared. However, in the case of such a common ground wire / terminal system, a difference in ground potential occurs between the lens barrel side of the photographing optical system and the camera body side, which may lead to destruction of the electronic circuits of both. For example, when the ground potential of the electronic circuit on the camera body side is zero volt and the ground potential of the electronic circuit on the photographing optical system lens barrel side is 1 volt (when the contact resistance of the terminal is 1 Ω and the ground current flows 1 A). When a signal of high level 5V and low level zero volt is applied to the electronic circuit on the side of the photographing optical system barrel from the electronic circuit on the side of the camera body, the electronic circuit on the side of the photographing optical system barrel is set to 1 more than the ground potential. Since a low voltage is also applied to the volt, the electronic circuit on the side of the taking optical system lens barrel may malfunction or be destroyed by heat.

[Object of the Invention]

An object of the present invention is to provide a lens barrel of an image taking optical system improved so as not to cause the above-mentioned destruction.

[Outline of Invention]

In a lens barrel of an improved photographic optical system according to the present invention, a power source is built-in, a first electronic circuit which is fed by the power source and outputs an information signal, and a first electronic circuit from the power source.
And a second power supply terminal, and first and second power supply terminals.
Of a grounding terminal, a signal terminal for an information signal from the first electronic circuit, and a lens barrel of a photographic optical system mounted on a camera having a mount, the lens barrel being rotated with respect to the mount of the camera. A mounting portion to be mounted on the camera, a motor circuit including a motor that drives a movable member in the lens barrel, a second electronic circuit that controls the motor circuit based on a signal to an input terminal, and third and fourth And a terminal group including fifth, sixth and seventh terminals, wherein the third terminal serves as the first power supply terminal and the fourth terminal serves when the lens barrel is mounted on a camera. The second feeding terminal, the fifth terminal are connected to the first installation terminal, the sixth terminal is connected to the second ground terminal, and the seventh terminal is connected to the signal terminal. A terminal group disposed at a position, and the motor circuit is connected to the third circuit. 5, the second electronic circuit is connected between the fourth and sixth terminals, and the seventh terminal is connected to the input terminal of the second electronic circuit. It is characterized by being connected to. In the camera of the present invention having such a configuration, since the connection terminal for the power ground line and the connection terminal for the signal ground are not shared, the electronic circuit breakage or malfunction occurring in the lens interchangeable camera described later will not occur. I have no fear of getting up.

Example of Invention

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

In the figure, 1 is an electronic circuit mounted on the camera body,
Reference numeral 2 is a power source such as a battery which is also housed in the camera body, 3 is power from the power source 2, and the electronic circuit 1
And a constant voltage output circuit, which is a power source for the electronic circuit on the side of the taking optical system lens barrel, which will be described later, 4 is an analog switch for turning on and off power supply to a motor (described later) mounted on the side of the taking optical system lens barrel, and 5 is A lens mounting mount provided on the camera body, 6 is a lens mounting detection switch provided in the input signal line of the electronic circuit 1 and arranged in the vicinity of the lens mounting mount 5, and 7 operates the lens mounting detection switch 6. It is a lens attachment / detachment response member. The lens attachment / detachment response member 7 is a swing member pivotally attached to the back side of the lens mounting mount 5, and has two arm portions on both sides of the pivot attachment point, and one arm portion is a photographing optical system mirror. It is driven by being engaged with a part of the camera mounting mount on the cylinder side, and the other arm portion presses one switch piece of the lens attachment detection switch 6.

The lens mounting detection switch 6 has two switch pieces that are separated from each other when the lens is not mounted. In the lens mounted state, the two switch pieces contact each other and the input terminal of the electronic circuit 1 and the constant voltage output. The output terminal of the circuit 3 is connected.

Reference numeral 8 denotes a connection terminal block for wiring connection arranged in the lower inner peripheral area of the lens mounting mount 5. The connection terminal block 8 has a connection terminal (or an electrical contact) provided on the side of the taking optical system lens barrel. ) Are provided with a large number of connection terminals (or contact pins) P _{1 to} P ₇ . Each of these connection terminals P _{1 to} P ₇ is biased by a spring so as to project from the front surface of the terminal block 8 to the front side, and each connection terminal is on a printed wiring board attached to the camera body. Are respectively connected to the wirings L _{1 to} L ₇ .

The wiring L ₁ connected to the connection terminal P ₁ serves as a motor power supply line for supplying power from a power supply 2 in the camera body to a motor (described later) in the photographing optical system lens barrel. Is equipped with an analog switch 4.

The wiring L ₂ connected to the connection terminal P ₂ is connected to the lens mounting detection switch 6 and the input terminal of the electronic circuit 1. The wiring L ₃ connected to the connection terminal P ₃ is a power ground line (power ground line), and the wiring L ₃ is connected to the negative electrode of the power supply 2.

The wiring L ₄ connected to the connection terminal P ₄ is adapted to be connected to the ground wire of the electronic circuit on the lens side described later, and the wiring L ₄ together with the ground terminal of the electronic circuit 1 on the camera body side is connected to the power supply 2 Is connected to the negative electrode of.

The wirings L _{5 to} L ₇ connected to the connection terminals P _{5 to} P ₇ are signal lines for exchanging signals between the electronic circuit 1 on the camera body side and the electronic circuit on the photographing optical system barrel side. The wirings L _{5 to} L ₇ are connected to the signal terminals of the electronic circuit 1.

The lens barrel of the photographing optical system of the present invention, which is detachably attached to the camera body having the above-described configuration, includes a focusing drive motor 9 and a stationary unit that switches the power supply direction to the motor 9. A switch device and an electronic circuit 10 for controlling the motor 9 and for exchanging various signals with the electronic circuit 1 on the camera body side are mounted, and attached to and detached from a lens mounting mount 5 on the camera body side. A camera mounting mount (not shown) that is freely fitted is provided, and a connection terminal block 11 that is disposed in the lower inner peripheral area of the camera mounting mount and faces the connection terminal block 8 on the camera body side. ing.

On the connection terminal block 11 provided on the lens barrel side of the photographing optical system, as shown in the drawing, the connection terminals P _{1 to} P ₇ on the camera body side are provided.
Seven connections may contact terminals _P 8 _{to P 14} (or contact pins) are provided, these connection terminals _P 8 to P
Wiring _L 8 _{~L 14} are connected to each other in _14.

The wirings L ₈ and L ₁₀ are connected to the motor 9 via a static switch device described later, and the other wirings L ₉ and L ₁₀ are connected.
_{11 to} L ₁₄ are power lines for flowing a large current, and as will be described later, L ₈ is a motor power supply line, and L ₁₀ is a power ground line for grounding one pole of the motor 9. ing.

The wiring L ₉ connected to the connection terminal P ₉ serves as an electronic circuit power supply line for supplying a current to the lens side electronic circuit 10, and is connected to the power supply terminal of the electronic circuit 10 and the connection terminal P ₉ And P ₂ to be connected to the wiring L ₂ on the camera body side.

The wiring L ₁₁ is connected to the ground terminal of the electronic circuit 10 and is also connected to the wiring L ₄ on the camera body side via the connection terminals P ₁₁ and P _4.
A grounding line (signal ground line) on the lens barrel side of the photographic optical system is constructed.

The wirings L _{12 to} L ₁₄ are connected to the signal terminals of the electronic circuit 10 and separately connected to the connection terminals P _{12 to} P ₁₄ , respectively, and the connection terminal P ₁₂ on the lens barrel side of the photographing optical system.
Is adapted to be connected each respective separately to the wiring _L 5 ~L ₇ of the camera body side through the to P ₁₄ and the camera body side connection terminal _P 5 to P _7. That is, the wirings L _{12 to} L
Reference numeral ₁₄ is a signal line on the side of the taking optical system lens barrel.

The static switch device for switching the power supply direction to the motor 9 is composed of four transistors T _{1 to} T ₄ of two pairs of one NPN transistor and one PNP transistor. Are connected to one pole of the motor 9 and the other pair is connected to the other pole of the motor. The emitters of each pair of PNP transistors T ₁ and T ₂ are connected to the wiring L ₈ provided on the interchangeable lens side,
The wiring L ₈ is connected to the wiring L ₁ on the camera body side via the connection terminal P ₈ in the connection terminal block 11. (That is, the wiring L ₈ constitutes a power supply line for supplying electric power from the power supply 2 to the motor 9 together with the wiring L _1. ) One pole of the motor 9 is a paired PNP transistor T _1.
And NPN transistor T ₄ are connected to the respective collectors of the motor 9, while the other pole of the motor 9 is connected to the respective collectors of the paired PNP transistor T ₂ and NPN transistor T ₃ . Meanwhile, each pair of NPN transistors T ₃ and T
Each emitter of ₄ is connected to the wiring L ₁₀ . The wiring L ₁₀ is a power ground line provided on the interchangeable lens side, and the negative electrode side of the motor 9 is connected to the connection terminal P _10.
Is connected to the connection terminal P ₃ on the camera body side via the wire and is connected to the negative electrode of the power supply 2 via the wiring L ₃ on the camera body side.

The electronic circuit 10 includes each transistor T of the static switch device.
A control terminal for controlling _{1 to} T ₄ is provided,
The control terminals and the bases of the transistors T _{1 to} T ₄ are connected by signal lines M _{1 to} M ₄ . In addition, R ₁ ~
R ₄ is a resistance.

A feature of the lens barrel of the photographing optical system of the present invention is that the ground wire and the ground connection terminal of the motor 9, the ground wire for the electronic circuit, and the ground connection terminal are respectively provided as described above. However, the operation of the illustrated components will be briefly described below.

(i) When the shooting optical system lens barrel is not attached to the camera body.

When the photographing optical system lens barrel is not attached, the connection terminal block 11 on the photographing optical system lens barrel side is connected to the connection terminal block 8 on the camera body side.
Since they are separated from each other, the connection terminals P _{1 to} P ₇ and P _{8 of} both are
~ P ₁₄ are not in contact with each other. Further, as shown in the figure, the lens mounting detection switch 6 provided on the lens mounting mount 5 of the camera body has its two switch pieces separated from each other. Therefore, the input terminal of the electronic circuit 1 is connected to the negative electrode of the power source 2 via the pressure reducing resistor RPD, and a low level voltage close to the ground voltage is applied to the input terminal. Therefore, the analog switch 4 is turned off (open state) from the output terminal of the electronic circuit 1.
Since the high level voltage is generated, the analog switch 4 is turned off and the power supply 2 and the connection terminal P ₁ are cut off.

(ii) When the shooting optical system lens barrel is attached to the camera body.

When the photographic optical system lens barrel is mounted on the camera body, the camera mounting mount of the photographic optical system lens barrel is rotated clockwise with respect to the camera lens mounting mount 5 in the figure. The lens mounting / demounting response member 7 is rotated counterclockwise about its pivot point by the camera mounting mount, and as a result, one arm of the lens mounting / demounting response member 7 causes one of the lens mounting detection switch 6 Since the switch piece of 1 is pushed, both switch pieces of the detection switch 6 come into contact with each other and the switch 6 is turned on. Therefore, since the 5V output terminal of the constant voltage output circuit 3 is connected to the input terminal of the electronic circuit 1 through the switch 6, a high level (5V) input voltage is applied to the input terminal. Therefore, the voltage level of the output terminal of the electronic circuit 1 the analog switch 4 from "H" to convert the "L" is turned on, a connection terminal P ₁ is connected to the positive pole of the power source 2.

On the other hand, when the photographing optical system lens barrel is completely attached to the lens mounting mount 5 of the camera body, the connection terminal P on the camera side is attached.
₁ because to P ₇ is contact as illustrated to the connection terminals _P 8 _{to P 14} of the imaging optical system lens barrel side, the wiring _L 1 ~L ₇ of the camera body side wiring of the imaging optical system lens barrel side _{L 8} To L ₁₄ via the connection terminals P _{1 to} P _14, and as a result, the wiring connection as illustrated is completed. (However, in the attached drawings, the lens attachment detection switch 6 is shown in an open state, but the switch 6 is kept closed when the lens attachment is completed.) After the lens attachment is completed, the camera body A control signal relating to camera operation (mainly focusing operation) is sent from the electronic circuit 1 on the side to the electronic circuit 10 on the side of the photographing optical system via the wirings L _{5 to} L ₇ and L _{12 to} L ₁₄ and at the same time, the photographing optical system. A signal related to the motor 9 is sent from the electronic circuit 10 on the system barrel side to the electronic circuit 1 on the camera side through the same wiring. For example, the control signal from the electronic circuit 1 causes the electronic circuit 10 to set the signal level of the wiring M ₁ to “L” and, at the same time, the wiring M 1.
_If the signal level of ₃ is set to “H”, the transistors T ₁ and T ₃ become conductive, and a current flows in the motor 9 in the direction of i through the wiring L ₈ and the transistor T ₁ as shown by the arrow in the figure. The motor 9 is rotated in the forward direction, and the current passes through the transistor T ₃ and is connected to the wiring L ₁₀ , the connection terminals P ₁₀ and P.
₃ , and returns to the negative electrode side of the power source 2 through the wiring L ₃ .

Further, when a signal to reverse the motor 9 from the electronic circuit 1 to an electronic circuit 10 through the wiring L ₅ ~L ₇ is sent to the wiring M ₂ from the electronic circuit 10 "L" when the level of the signal is issued at the same time wiring the _{M 4} "H" level signal is issued (at this time, the signal level of the wires _{M 1} is "H", the signal level of the wiring _{M 3} are has become "L".), as a result, transistor When T ₂ and T ₄ are conducted, a current in the direction opposite to the arrow i shown in the drawing flows into the motor 9 from the transistor T ₂ and the motor 9 reversely rotates.

As described above, the outflow current from the motor 9 is the wiring L on the lens side regardless of whether the motor 9 is rotating normally or reversely.
₁₀ and the connection terminal P ₁₀ on the side of the photographing optical system, and further through the connection terminal P _{3 on the} camera body side and the wiring L ₃ on the camera body side to return to the negative electrode of the power supply 2. Since a contact resistance is generated between the connection terminals P ₁₀ and P ₃ (that is, a voltage drop is generated) when electricity is applied to the camera, the potential of the wiring L ₁₀ on the lens barrel side of the photographic optical system and the wiring L ₃ on the camera body side are reduced. Since an electric potential difference is generated between the electric potential (that is, the ground potential of the power supply 2), the actual ground potential of the motor 9 is considerably higher than the ground potential of the power supply 2. (For example, if the current flowing into the motor 9 is 1 amp, the connection terminal P
_If the contact resistance between ₃ and P ₁₀ is 1 ohm, the ground potential of the motor 9 will be 1 volt instead of zero volt. In the conventional lens barrel of the photographic optical system, the electronic circuit, the ground wire of the motor, and the grounding connection terminal are shared, so that the current flowing into the motor 9 causes the electronic circuit 10 on the lens barrel side of the photographic optical system.
The ground potential of the photographing optical system lens barrel side electronic circuit may rise above the signal potential when the ground potential of the photographing optical system barrel side electronic circuit fluctuates and the current flowing into the motor 9 is large. However, in the present invention, the signal ground wire and the connection terminal of the electronic circuit and the ground wire and the connection terminal of the motor are provided independently and independently of each other on both the lens barrel side of the photographing optical system and the camera body side. Therefore, the electronic circuit is not affected by the motor.

〔The invention's effect〕

As described above, according to the present invention, the electronic circuit on the side of the photographing optical system and the electronic circuit on the side of the camera body are destroyed by the electric current supplied to the motor mounted on the side of the photographing optical system. Provided is an improved lens barrel of photographing optics which is free from malfunction.

[Brief description of drawings]

The accompanying drawings are schematic diagrams showing the electrical connection of a lens barrel and a camera body of an improved photographing optical system according to the present invention in a coupled state. 1, 10 ... Electronic circuit, 2 ... Power supply, 3 ... Constant voltage output circuit, 4 ... Analog switch, 5 ... Mounting for mounting lens of camera body, 6 ... Lens mounting detection switch, 7 ... Lens Attachment / detachment response member, 8 ... Connection terminal block on camera body side, 9 ... Motor, 11 ... Connection terminal block on lens barrel side of photographing optical system

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication location G03B 13/36 (56) References JP-A-59-176732 (JP, A) JP-A-58- 83823 (JP, A) Mitsuru Mogi, "Troubleshooting Series ▲ ○ 2 ▼ Electronic Circuit Noise &Troubleshooting" CQ version (Sho 55.3.15) 9-11 Photo Industry June 1985 PP. 78-85 Asahi Camera July 1985 PP. 259 -265

Claims (1)

[Claims] 1. A first electronic circuit which has a built-in power supply, is connected between both output lines of the power supply, is fed by the power supply, and outputs an information signal from a signal output section; and a first electronic circuit from the power supply. Shooting optics mounted on a camera having first and second power supply terminals, first and second ground terminals for the power source, signal terminals for information signals from the first electronic circuit, and a mount. In a lens barrel of a system, a mounting portion that mounts the lens barrel on the camera by rotation with respect to the mount of the camera, a motor circuit including a motor that drives a movable member in the lens barrel, and a signal to an input terminal based on A second electronic circuit for controlling the motor circuit, and a terminal group including third, fourth, fifth, sixth, and seventh terminals, the first electronic circuit controlling the motor circuit when the lens barrel is attached to the camera. 3 terminal is the first power supply terminal A fourth terminal to the second power supply terminal, a fifth terminal to the first ground terminal, a sixth terminal to the second ground terminal, and a seventh terminal. A group of terminals arranged at positions respectively connected to the signal terminals is provided, the motor circuit is connected between the third and fifth terminals, and between the fourth and sixth terminals. A lens barrel of a photographic optical system, wherein the second electronic circuit is connected, and further the seventh terminal is connected to the input terminal of the second electronic circuit.