JPH0448374B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a camera system comprising a camera body and an interchangeable lens.

[Conventional technology]

Modern cameras have become increasingly automated and are equipped with automatic exposure control devices, automatic focusing devices, automatic light control devices, etc., so various electronic circuits, motors, batteries, etc. are installed inside the camera.

In interchangeable lens cameras that are equipped with the various devices described above, motors and electronic circuits are installed not only on the camera body side but also on the lens side, so it is necessary to connect the camera body and lens. The mount portion is provided with an electrical circuit connection connector having electrical contacts, that is, connection terminals, for electrically connecting various devices inside the camera body and various devices inside the lens.

These connection terminals include terminals for supplying power and terminals for sending and receiving signals.
In particular, the terminal for supplying power has two terminals, one for supplying (+) side power and the other for supplying (-) side power. Regarding the (-) side power supply, it is also possible to use electrical connections other than contacts, such as a mount.
Regarding the (+) side power supply, it is common to have two systems: a power supply power supply for operating actuators such as motors, and a power supply power supply for operating electronic circuits for control and information communication. Each is connected to a separate terminal. The problem here is poor contact, or situations where only power is supplied and power to the control electronic circuit is not supplied, or is supplied intermittently during the process of attaching the lens to the camera. This is the case when it becomes. In such a state, malfunctions such as the motor starting to move may occur. In other words, the motor is ready to operate because only power is supplied, but the power to the control electronic circuit is incomplete, so a haphazard control signal is issued, ensuring normal operation of the motor. You will not be able to do it.

Similarly, problems can occur if the contacts are not making good contact or if the communication line of the electronic circuit on the camera side does not make complete contact with the communication line on the lens side during the installation process, and only power is supplied. be. In such a state, the control electronic circuit on the lens side will no longer correctly receive communication information from the camera side. As a result, a normal motor rotation command may be mistaken for a reverse rotation command, a stop command may not be received, and normal operation cannot be guaranteed. Similarly, if foreign matter such as conductive dust or water adheres to the communication line, the communication line may become short-circuited with the mount, or adjacent connection terminals may be short-circuited. In this case as well, the control electronic circuit on the lens side will receive communications from the camera side by mistake, and normal operation cannot be guaranteed for the same reason.

〔the purpose〕

The present invention solves the above-mentioned conventional drawbacks, and when an interchangeable lens is attached to a camera body,
After supplying power to the lens-side electric circuit for communication, performing digital communication between the camera body and the interchangeable lens, and determining that the connections between each terminal are normal,
To provide a camera system that can reliably prevent malfunctions by supplying power to a power supply terminal for enabling an in-lens motor to operate.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is an electronic circuit mounted on the camera body, 2 is a power source such as a battery that is also housed in the camera body, and 3 is a power source that is supplied with power from the power source 2, and the electronic circuit 1 and the lens described below. 4 is an analog switch that turns on and off the power supply to the motor mounted on the lens side (described later); 5 is a mount for mounting the lens on the camera body;
Reference numeral 6 denotes a lens attachment detection switch provided on the input signal line of the electronic circuit 1 and located near the lens attachment mount 5; and 7 a lens attachment/detachment responsive member for actuating the lens attachment detection switch 6. The lens attachment/detachment response member 7 is a swinging member pivotally attached to the back side of the lens attachment mount 5, and has two arms on both sides of the pivot point, one of which is used for attaching the lens to the camera. The other arm is adapted to press one switch piece of the lens attachment detection switch 6.

The lens attachment detection switch 6 has two switch pieces that are separated from each other when the lens is not attached, and when the lens is attached, the two switch pieces contact each other to connect the input terminal of the electronic circuit 1 and the constant voltage output. It is designed to be connected to the output terminal of circuit 3.

Reference numeral 8 denotes a connection terminal block for wiring connection arranged in the lower inner peripheral area of the lens mounting mount 5, and the connection terminal block 8 has a connection terminal block (or electrical contact point) provided on the lens side. A large number of contacting terminals (or contact pins) P ₁ to _{P 7} are provided. Each of these connection terminals P ₁ to _{P 7} is biased by a spring so as to protrude forward from the front surface of the terminal block 8, and each connection terminal is connected to a printed wiring attached to the camera body. wiring on board
Each is connected to _L1 to _L7 separately.

The wire L ₁ connected to the connection terminal P ₁ is from the power supply 2 inside the camera body to the motor inside the lens (described later).
This is a motor power supply line for supplying power to the motor, and is provided with the analog switch 4 as described above.

The wiring _L2 connected to the connection terminal _P2 is a power supply line for the lens 1c to which the lens attachment detection switch 6 and the input terminal of the electronic circuit 1 are connected. Further, the wiring L ₃ connected to the connection terminal P ₃ serves as a power ground line, and the wiring L ₃ is connected to the negative electrode of the power source 2 .

The wiring L ₄ connected to the connection terminal P ₄ is connected to the grounding wire of the electronic circuit on the lens side, which will be described later, and the wiring L ₄ is connected to the grounding terminal of the electronic circuit 1 on the camera body side as well as the power supply 2. connected to the negative terminal of

Wiring L ₅ ~ _{L 7} connected to connection terminals P ₅ ~ P ₇
is a signal line for transmitting and receiving signals between the electronic circuit 1 on the camera body side and the electronic circuit on the lens side, and each wiring _L5 to _L7 is connected to the signal terminal of the electronic circuit 1. .

The interchangeable lens, which is configured to be detachably attached to the camera body configured as described above, includes a focusing drive motor 9, a stationary switch device that switches the direction of power supply to the motor 9, and a stationary switch device that switches the direction of power supply to the motor 9. The camera mount is equipped with an electronic circuit 10 that performs control and exchanges various signals with the electronic circuit 1 on the camera body side, and is removably fitted to a lens mount 5 on the camera body side. mount (not shown), and a connection terminal block 11 that is disposed in the lower inner peripheral area of the camera attachment mount and faces the connection terminal block 8 on the camera body side.

The connection terminal block 11 provided on the interchangeable lens side has connection terminals on the camera body side as shown in the figure.
Seven connection terminals P ₈ to _{P 14} (or contact pins) that can contact P 1 to P ₇ are provided, and wiring L ₈ to L ₁₄ is connected to each _of these connection terminals P ₈ to _{P 14} . It is connected.

Wires L ₈ and L ₁₀ are connected to motor 9 via a static switch device, which will be explained later, and other wires
Compared to L ₉ and L ₁₁ to _{L 14} , it is a power line for flowing a large current, and as will be explained later, L ₈
is a motor power line, and _L10 is a power ground line for grounding one pole of the motor 9.

The wiring L ₉ connected to the connection terminal P ₉ serves as an electronic circuit power line for supplying power to the lens-side electronic circuit 10, and is connected to the power terminal of the electronic circuit 10 as well as the connection terminal P _9. It is connected to the wiring _L2 on the camera body side via P2 and _P2 .

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 .
It constitutes a ground line (signal ground line) on the interchangeable lens side of the electronic circuit 10.

The wires L ₁₂ to _{L 14} are connected to the signal terminals of the electronic circuit 10 and are also separately connected to the connection terminals P ₁₂ to P ₁₄ , and are also connected to the connection terminals P ₁₂ to P 14 on the lens side.
_P14 and connection terminals _P5 to _P7 on the camera body side to be separately connected to wires _L5 to _L7 on the camera body side, respectively. That is, the wiring L ₁₂ ~
_L14 is the signal line on the lens side.

Transmission data from the electronic circuit 1 is received by the electronic circuit 10 via the wiring L ₅ , connection terminal P ₅ , connection terminal P ₁₂ , and wiring L ₁₂ , and transmission data from the electronic circuit 10 is received through the wiring L ₁₃ and the connection terminal P ₁₃ , is received by the electronic circuit 1 via the connection terminal P ₆ and the wiring L ₆ .

Further, in order to synchronize serial communication with the electronic circuit 10, a clock pulse is transmitted from the electronic circuit 1 to the electronic circuit 10 via the wiring L ₇ , the connecting terminal P ₇ , the connecting terminal P ₁₄ and the wiring L ₁₄ .

The static switch device for switching the direction of power supply to the motor 9 consists of one NPN transistor and one
It consists of two sets of four transistors T ₁ to T ₄ paired with PNP transistors, one pair is connected to one pole of the motor 9, and the other pair is connected to the other pole of the motor. ing. Also, for each pair
The emitters 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 a connection terminal P ₈ in the connection terminal block 11 . (In other words, the wiring L ₈ and the wiring L ₁ constitute a power supply line for supplying power from the power source 2 to the motor 9.) One pole of the motor 9 is connected to a paired PNP transistor T ₁ . The other pole of the motor 9 is connected to the collector of each of the NPN transistors T ₄ , while the other pole of the motor 9 is connected to the collector of each of the NPN transistors T ₄ and the NPN transistor
T is connected to the collector of each of ₃ . on the other hand,
The emitters of each pair of NPN transistors T ₃ and T ₄ are connected to wiring L ₁₀ . Wiring _L10 is a power ground line provided on the interchangeable lens side, and connects the negative pole side of motor 9 to connecting terminal _P3 on the camera body side via connecting terminal _P10 , and also connects the wiring L on the camera body side. Power supply 2 through ₃
connected to the negative terminal of

The electronic circuit 10 is provided with a control terminal for controlling each transistor T ₁ to T ₄ of the static switch device, and each control terminal and each transistor T _{1 to} T 4 are connected to each other.
It is connected to each base of T ₄ by signal lines M ₁ to _{M 4} . Note that R ₁ to R ₄ are resistances.

Reference numeral 21 denotes a switch that is turned on, for example, by the first stroke of a shutter button (not shown). During the first stroke of the shutter button, the camera performs photometry, and the shutter speed and aperture value are displayed on an external display (not shown). Although only one switch is shown here, cameras have recently been proposed that display the shutter speed and aperture value on an LCD display, but in such cameras, it is necessary to press the shutter button in the first step. It is inconvenient for the user if the setting values etc. are not displayed on the LCD display, so some cameras are designed so that a switch is activated when some operating member is moved. Taking this into consideration, a plurality of switches may be provided instead of being activated by the first stroke of the shutter button as described above. _R5 connected to switch 21 is a pull-up resistor.

The operation of the illustrated components will be briefly explained below.

(1) When no lens is attached to the camera body.

When the lens is not attached, the connection terminal block 11 on the lens side is separated from the connection terminal block 8 on the camera body side, so the connection terminals P ₁ to P ₇ and P ₈ on both sides are connected to each other.
~ _P14 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 is in a state where two switch pieces are separated from each other. Therefore, the input terminal of the electronic circuit 1 is connected to the negative electrode of the power supply 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 a high level voltage is generated, the analog switch 4 is turned off, and the power supply 2 and the connection terminal _P1 are cut off.

() When a lens is attached to the camera body.

When attaching a lens to the camera body, the lens attachment mount is rotated clockwise in the figure with respect to the camera lens attachment mount 5, so the lens attachment/detachment responsive member 7 is rotated by the camera attachment mount of the lens. is rotated counterclockwise about its pivot point, and as a result, one switch piece of the lens attachment detection switch 6 is pushed by one arm of the lens attachment/detachment responsive member 7. , both switch pieces of the detection switch 6 come into contact with each other, and the switch 6 is turned on. Therefore, a voltage for operating the electronic circuit 10 is applied to the 5V output terminal of the constant voltage output circuit 3 via the switch 6 to the wiring L ₂ and the connection terminal P ₂ .

On the other hand, when the lens is completely attached to the lens mounting mount 5 of the camera body, the connection terminals P ₁ to _{P 7} on the camera side are in contact with the connection terminals P ₈ to _{P 14} on the lens side as shown in the figure. Therefore, the wirings L ₁ to _{L 7} on the camera body side are connected to the wirings L ₈ to _{L 14} on the lens side via the connection terminals P ₁ to _{P 14} , and as a result, the wiring connections as shown are completed. (However, although the lens attachment detection switch 6 is shown in the open state in the attached drawing, the switch 6 remains closed when the lens attachment is completed.) Command data is transmitted serially from the electronic circuit 1 on the camera side to the electronic circuit 10 on the lens side, and then the lens transfers the requested data to the camera side in accordance with this command data.

After the lens is attached, the electronic circuit 1 on the camera side sends 8-bit command data "φA" expressed in hexadecimal notation to the electronic circuit 10 on the lens side, and at the same time, the camera side sends invalid data from the lens side to the electronic circuit 10 on the lens side. φφ” is received. FIG. 3 is a timing chart showing this communication state. At the same time as transmitting "φA", the camera-side electronic circuit 1 outputs a clock pulse to the DCLK signal line for synchronizing the communication.

Next, the lens-side electronic circuit 10 determines the meaning of "φA" and outputs "AA" when the next communication synchronization clock pulse is output from the camera side. At this time, the camera side outputs invalid data "φφ" to the lens side. FIG. 4 is a timing chart showing this communication state.

When the camera side receives "AA", it assumes that communication is normal and generates a low level voltage from the output terminal of the electronic circuit 1 on the camera side, turns on the analog switch 4, and turns on the (+) of the power supply 2.
The side terminal and the connection terminal _P1 are electrically connected.

On the other hand, if the communication is not performed correctly and the electronic circuit on the camera side cannot correctly receive "AA", the high level voltage is continued from the output terminal of the electronic circuit 1 on the camera side and the analog switch 4 is turned off. The power supply 2 and the connection terminal _P1 are left unconnected. Although communication has been described above as 8-bit data, it is not limited to 8-bit data.

Communication between the camera and the lens will be explained in the same manner as above.

After the lens attachment is completed, control signals related to camera operations (mainly focusing operations) are sent from the electronic circuit 1 on the camera body side to the electronic circuit 10 on the lens side via wiring L ₅ to L ₇ and L ₁₂ to L ₁₄ . At the same time, a signal regarding the motor 9 is sent from the electronic circuit 10 on the lens side to the electronic circuit 1 on the camera side via the same wiring. The timing of communication is as described above, so it will be omitted, but for example, when the electronic circuit 10 changes the signal level of the wiring M ₁ to "L" by the control signal from the electronic circuit 1, the signal level of the wiring M ₃ changes simultaneously. When set to “H”, the transistor
_T1 and _T3 become conductive, and current flows into the motor 9 in the direction of arrow i as shown by the arrow through the wiring _L8 and the transistor _T1 , and the motor 9 is rotated in the forward rotation direction.
The current flows back to the negative electrode side of the power supply 2 through the transistor T ₃ , the wiring L ₁₀ , the connecting terminals P ₁₀ and P ₃ , and the wiring L ₃ .

Furthermore, when a signal to reverse the motor 9 is sent from the electronic circuit 1 to the electronic circuit 10 through the wiring L ₅ to L ₇ , at the same time as the signal of "L" level is sent from the electronic circuit 10 to the wiring M ₂ . “H” for wiring _M4
level signal is output (at this time, the signal level of the wiring _M1 is "H" and the signal level of the wiring _M3 is "L"), and as a result, the transistors _T2 and
A current in the direction opposite to the arrow 1 shown in the figure flows into the motor 9 from the transistor T ₂ to which T ₄ is conducting, causing the motor 9 to rotate in reverse.

A flowchart executed according to the present invention will be explained based on FIG. 2. First, in # _C1 , it is determined whether or not the state of the switch 21 has been changed. If there is no change, return to the starting position, but if there is a change, proceed. Next, # _C2 is for determining whether or not the lens has been completely attached. In FIG. If it is, proceed as is, and if it is off, power will not be supplied from power supply 2 to connection terminal _P1 . # _C3 connects “φA” expressed in hexadecimal notation while outputting the synchronous clock pulse to the connection terminal _P5 ,
It transmits to the lens side via _P12 and receives invalid data "φφ" at the same time, and # _C4 also outputs the synchronized clock pulse while transmitting data from the lens side via connection terminals _P13 and _P6 . The data is received by the camera body and invalid data is sent at the same time. # _C5 determines whether the received data is "AA" in hexadecimal notation, and if it is not "AA", the power supply 2 is not supplied to the connection terminal _P1 , but
If it is “AA”, proceed directly. # _C6 is for energizing the power supply 2 on the camera body side to the motor 9 on the lens side via the connection terminals _P1 and _P8 .

〔Effect of the invention〕

As explained above, according to the present invention, unless communication between the lens and the camera is properly performed, power is not supplied to the lens-side power terminal for supplying power to the lens-side motor. Even if an erroneous control signal is output from the motor control electronic circuit due to a poor contact in the communication line or a poor contact in the power supply line of the electronic circuit, it is now possible to completely prevent motor malfunction. Ta.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the state of electrical connection between an improved camera and an interchangeable lens according to the present invention, and FIG. 2 is a flowchart for implementing the present invention. Figures 3 and 4 are time charts. 1, 10...electronic circuit, 2...power supply, 3...constant voltage output circuit, 4...analog switch, 5...
Lens attachment mount on camera body, 6...Lens attachment detection switch, 7...Lens attachment/detachment response member, 8...Connection terminal block on camera body side, 9...
...Motor, 11...Connection terminal block on the interchangeable lens side,
21...Switch.

Claims (1)

[Scope of Claims] 1. A camera system comprising a camera body having a power supply device and an interchangeable lens configured to be detachably attached to the camera body, wherein the camera body has a first camera-side power terminal and a first camera-side power terminal. a second camera-side power terminal, a camera-side communication terminal for communication with the interchangeable lens, and a camera-side communication terminal for controlling power supply to at least the second camera-side power terminal and communicating with the interchangeable lens via the camera-side communication terminal; a camera-side electric circuit for performing communication, and the interchangeable lens is provided with a first lens-side power terminal connected to the first camera-side power terminal, and a second camera-side power terminal. The second lens-side power supply terminal is connected to the camera-side communication terminal, the lens-side communication terminal is connected to the camera-side communication terminal, and the first lens-side power supply terminal operates. a lens-side electric circuit that communicates with the camera-side electric circuit, and a motor that can be operated by receiving power from the second lens-side power terminal, and when the interchangeable lens is attached to the camera body. , supplying power only to the first camera-side power terminal to enable communication between the camera-side electric circuit and the lens-side electric circuit, and transmitting a specific digital signal from the camera-side electric circuit to the lens-side electric circuit. When a signal is communicated and a specific digital signal is communicated from the lens-side electric circuit to the camera-side electric circuit, the camera-side electric circuit is connected to the second camera-side power terminal. A camera system characterized by supplying power to the camera.