JPS59204013A - Automatic focus control device of lens interchangeable type camera - Google Patents

Abstract

PURPOSE:To simplify a connecting mechanism, and to control a long focus lens by using one bi-directional electric signal line for the interface of a camera side and a lens side, opening and closing a power source of the lens side, and executing delivery of the signal of a CPU of the camera body side and the lens side. CONSTITUTION:A bayonet part is provided with connecting terminals such as a camera body side connecting terminal 27, lens side connecting terminal 29, etc. for outputting a signal, and through these connecting terminals, a linear electric signal is transferred from a CPU3 of the camera body side to a CPU35 of the lens side with regard to a time series of a command, a numerical data, etc. In the same way, the electric signal is transferred from the CPU35 of the lens side to the CPU3 of the camera body side, as well. In this way, the electric signal is transmitted and received by one line, therefore, a circuit having a bi-directional electric characteristic is used as an interface circuit; an interface circuit 12 and an interface circuit 37 are provided on the camera side and the lens side, respectively, and these interface circuits are connected to each other through the camera body side connecting terminal 27 and the lens side connecting terminal 29.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an automatic focus control system for an interchangeable lens camera: P'l
”, if you use iT, there is a control CP on the lens side.
l-J, Mork] - Live circuit, lens drive motor, etc. are arranged i, 4j The lens drive of the interchangeable lens is controlled by receiving and receiving signals from the lens side and the camera body (191 type canola). The present invention relates to an automatic focus control device.

An automatic focus control device is provided in which the lens of the interchangeable lens is driven by a motor built into the car body. However, in order to make the doll's interchangeable lens work without moving, it is necessary to use a motor with a large output. 2. There is a role 61-man J.

・A proposal has been made to incorporate a motor, etc. into such a lens to provide an automatic focusing system, part 1).

However, various controls other than automatic focus adjustment are also required on the camera body side, and when the focus detection sensor 4) is installed on the camera body side, control signal reception is required on the lens side and the camera body side. It must be passed or it becomes J:.

I' huge (J+ focus J!) For Section 11, it becomes necessary to exchange various signals, and it is necessary to provide a large number of one concubine point.

The object of the present invention is to provide an automatic focus adjustment camera of the above type, in which all signals related to focus adjustment between the CPU on the body side and the CPU on the lens side can be exchanged using a single signal line. An object of the present invention is to provide an automatic focus control device for a type camera.

In order to achieve the above object, an automatic focus control device for an interchangeable lens camera according to the present invention includes a start switch, a focus detection sensor, a camera temperature measurement CPU for control, and an interface circuit for transmitting and receiving signals controlled by the CPU. A lens-side interface circuit that is connected to the camera body side and the interface circuit provided with one connection line, a power hold circuit that holds a lens-side power supply circuit, a lens-side CPU for control, a mork drive circuit, and a lens. It consists of a drive motor, an encoder that detects and inputs the actual lens movement amount, and a lens provided with a terminal that allows the camera body to recognize that this lens has a lens drive motor. When it is determined that the lens attached to the camera body is of the above type, a command is sent to set the internorth circuit on the camera body side to output mode I- and turn on the lens side power supply, and Detection - 1) Reads the control margins regarding the direction and amount of movement of the lens from the sensor and judges them. 1.1, the lens-side CPU sets the lens-side inkjet circuit to reception mode 1ζ, and sets the control take to j:)1.1. Inserted, said motor drive circuit, Lenz jljt7 movement/seven-tater,
Detect and input the actual lens movement distance] Operate the encoder and based on the control data (after completing the lens drive, enter the lens side interface), set the circuit to the output mode and set the camera body to the output mode. A command indicating the end of the motor drive is sent to the side (7, j); 1) The CPU on the body side operates the focus detection sensor 1, and executes a command related to the direction and amount of movement of the lens. The Joro control data is read again, it is determined whether the take is within the i'1 content range, and if it is within the allowable range, the next control is entered.

Hereinafter, the present invention will be explained in more detail with reference to the drawings and the like.

FIG. 1 is a system block diagram of a camera controlled by a control circuit according to the present invention.

Although the control circuits are shown outside the camera body or lens for ease of understanding, the respective circuits are housed within the camera body or lens.

The bayonet part, which is the connection device between the camera body and the lens, has a connection terminal 27 on the camera body side for signal reception.
．． Connection terminals such as a lens side connection terminal 29 are provided.

Through these connection terminals, the CPU on the camera body side
3 transmits serial electrical signals in time series such as commands and numerical data to the CPU 35 on the lens side.

Similarly, from the CPU 35 on the lens side to the CPU on the camera body side.
The aforementioned electrical signal is also transmitted to U3. In order to transmit and receive electrical signals through a single line in this way, a circuit having bidirectional electrical characteristics is used as an interface circuit. An interface circuit 12 is provided on the camera side, and an interface circuit 37 is provided on the lens side. 27. Lens side connection θ1
1.1 children 29 are connected to each other.

On the lens side, there is a motor 20 for lens insertion having a drive output corresponding to the size of the lens).

The Tanabata 20 is driven by the output of the motor me 11 circuit 36 controlled by the CPU '35, and the float 1 (j
.

An engine 40 is provided to measure the amount of extension of the lens 15. The second encoder plate 39c;+: of this encoder is connected to the lens drive system through both gears.
i! i and can be rotated by an angle corresponding to the amount of lens drive of the lens drive system.

The encoder plate 39 of the Ninninota is equipped with a Siemens scute, and when the encoder plate 39 is rotating, intermittent light pulses from the LED are supplied to the phototransistor included in the photocoupler of the encoder 40 on the lens side. A low, high-level pulse signal appears at the output. By measuring this pulse, lens 1
Obtain data for the amount of 5 rolled out. In order to improve the reliability of the signal, the output signal of the phototransistor is waveform-shaped into a rectangular wave by the preamplifier 38 and then supplied to the input port of the CPU 35.

The lens side is provided with its own power supply 33 and a power hold circuit 34 that boosts the output voltage of this power supply 33 and holds this voltage according to a signal. Each of the circuits on the lens side receives an operating voltage from this power hold circuit 34.

Although not shown in this figure, a hinge is provided on the lens side to detect the limit of movement of the brush/lens in the infinite direction and the limit of movement of the lens in the close-up direction.

On the camera body side, the mirror 14 passes through the lens 15.
The focus detection sensor 6 is arranged from the point detection sensor 6 from which the point detection sensor 6 is arranged. C1) u 3 c is input.

This car body is a lens of a different type than the above-mentioned lens, but it also has an automatic focus adjustment lens that does not have a built-in motor and is not resistant to automatic focus adjustment when attached. The lens also has a configuration (4j) so that the detection results of the focus detection sensor 6 (1ii+) can be used.

Bar 1 no pole)) u path 2 is the voltage of power supply 1 on the car body side) - 'r'+' 1. E L/Hold this voltage and supply the operating voltage to each time j+'3 of the Kala body (jjll).

j:-1-ta-la-f) The above-mentioned power halt circuit +l'i'i 34 circuits are provided. Each circuit on the lens side is supplied with an operating voltage of 2LJ from this bar-no-bold circuit 34. )) When an autofocus rail lens that does not have a built-in rotor as mentioned above is installed, the CPU
3 controls the motor life circuit 4 to drive the motor 7.

The rotation of the motor 7 is transmitted via a gear train 8.9.10 to a coupler 11 which drives a lens drive mechanism on the lens side.

In order to detect this amount of drive, a side encoder 52 is used.
is provided.

Reference numeral 21 indicates a release button, and reference numerals 22 and 23 indicate first and second release contact pieces.

The operation of the first release contact piece 22 causes the automatic focus adjustment of the focus detection lens, and the operation of the second release contact piece 23 starts the automatic exposure adjustment and release operations on the condition that the automatic focus adjustment is completed.

When the automatic focusing lens with built-in motor is attached to the camera body, the CPU 3 on the camera body side controls both the rotational direction of the motor 20 on the lens side and the amount of lens drive (driving wheel converted into the number of pulses of the encoder 40). It is transmitted via the interface circuit 37, which is a directional circuit. When the CPU 35 on the lens side receives the data, it operates the motor drive circuit 36 to control the motor 20 while monitoring the amount of lens drive based on the output of the encoder 40 on the lens side.This point will be described in detail later. .

FIG. 2 is a circuit embodiment showing in detail the circuit portion of the device shown in FIG.

1f! 3 Turn on the main switch (MSWB) and press release (No. 22).
'Battery voltage or power halt on camera body side 1!
Old tb 2 (7) l) The voltage boosted by the c/dc conharc and stabilized by the constant voltage circuit is sent to CPU3.
fed to birds. In order to avoid power consumption of battery 1,
When CPU3 completes a series of sequential operations, the CPU3 boat)]24 turns the power off to High.
Generate l+iiA ``'j. As a result, the thyristor SCR of the power bold circuit 2 on the body side turns off G, and the voltage Δl!jVDDB (V on the body side
DD) is automatically blocked tt:li. Therefore, C
LIJ the power supply of PU3 itself.

The power connection of the circuit on the camera side is controlled by signals from the camera, provided that the photographer turns on the main SW (MSWL) on the camera side for 10 minutes. .

When the release SW on the camera side is pressed, the CPU 3 executes the command and generates a power-on signal (VL=H4gl+) at the terminal 29 on the lens side in the initial state. This signal is applied to the transistor T r 1 of the power bold circuit on the lens side via the diode DL. As a result, the transistor Tr2 is made conductive, the thyristor 5CRL is turned on, and the CPU 35 on the lens side is connected to the power source and starts control.

FIG. 3 is a flowchart for explaining the operation of the CPU 3 on the camera body side, and FIG. 4 is a flowchart for explaining the operation of the CPU 35 on the lens side.

FIG. 5 is an overall flowchart showing the program of FIG. 3 and the program of FIG. 4 together with the details omitted, and simply represents the gist of the present invention.

The programs shown in FIGS. 3 and 4 will be briefly explained in relation to FIG. 5.

The part shown in FIG. 3(A) is a block 1.0 that is generally used both when the focus is adjusted using the motor on the lens side and when the focus is adjusted using the motor on the body side. It is J-gram. List the major programs.

II Clam Start (Step 700) Determine the type of lens attached to the car body (Su-knob 702) When the lens attached to the Norapoti is a long focal length lens, send an L S RON signal to the lens side. do(
Steps 703 and 704) Indicate the current position from the focus detection sensor on the camera side (11
Importing the number, that is, measuring it (step 713):! :
l i:L! Focus determination to determine whether focus adjustment is necessary based on the l'l'l fixed result (steps 721 to 723)
The next control AE operation mode is executed when it is determined that the focus adjustment is completed in the step described above.
! ] 0) 7,; ;:;l-・5ii[1fj! Day, J! : After the above-mentioned focus determination (steps 721 to 72+1) is executed, if focus adjustment is necessary, each focus adjustment is executed again.

The part shown in FIG. 3(B) is mainly a program for driving the lens by the motor on the camera side.

(Step 724) is a step in which the program branches depending on whether a long focal length lens is attached (LMOTFLG=1).

(Steps 731 to 746) are a focus adjustment program by the motor on the camera body side when LMOTFLG=0.

(Steps 743 to 751) This is a display control program related to Hiromisoto Inchi.

When the execution of each program is completed, the process returns to step 706) before the measurement (step 713) in FIG. 3(A).

The part in FIG. 3(C) includes a program (steps 762 to 771) for exchanging data with the CPU on the lens side when (LMOTFLG=1.) and a program related to the limit switch.

The part shown in FIG. 4(A) is a data exchange program between the lens side and the camera body side, and corresponds to a part of FIG. 3(C).

The part shown in FIG. 4 (■3) is a lens drive unit driven by a lens-side motor, and its configuration is approximately the same as the part shown in FIG. 3 (B).

1, l:♀10 Before going into the explanation, constants related to control and the meanings of terms will be explained. FIG. 5 is a graph for explaining the meaning of constants.

All control constants are determined in units of one output pulse of the encoder 11.

(N) A movement value 1jjtJ that indicates how far the lens should be moved in terms of the output pulse of the encoder, (Nm) 1' which indicates whether to perform full drive or fine drive based on the above (N). Constant used when cutting.

If N≧Nrn, it is assumed that the amount of movement is large and the vehicle is set to full drive.

(Nstop) Full drive is performed and when the distance to the control target position reaches N5top, full drive is stopped and the 1/- key is applied. In other words, the constant is selected so that when N5top is reached during full drive, when full drive is stopped and the brake is applied, the lens will be at or near the control target position.

(No) Perform control and activate the distance measurement circuit to create a new (N)
A constant that determines that control has ended when (N) is smaller than (No), and a tolerance constant.

(ΔNo) A constant for expanding the allowable error range introduced when controlling the autofocus 11i1J at the infinity side movement limit of the lens.

Note that these constants are illustrated in FIG.

Operation Abbreviations and Definition of Terms ○LSW: Abbreviation for Limisoto Switch ○LSWFLG: Abbreviation for Limisoto Switch Flag In sequential control, it can generally be represented by a logic circuit composed of a combinational circuit and a sequential circuit.

When the logic circuit is in a certain state (S n-1) and an input signal is input, it moves to the next state (Sn) and outputs to the output (Zr+).

This means that the output is related to the past input array.

If the LSW (limit switch) is turned on in a state one step before the current sequential control state, LS
WFLG (Limitosutui Nochiflag) is secerated to 5 (,) implanted "]" (Present perfect wind ■NL S W: Closest side sushi) 1-Switch abbreviation JU1 side Ririmino 1-Switches is in the closest position This is a switch that turns on when the object is moved.

○N L, S~Il:'r-c: Abbreviation of closest limit switch flag 1-J When I-SW (closest limit switch) is turned on, record this state in 4.1. To do this, set CP tJ iJ: N L S W F L G to "1".

01・' L S W : Abbreviation of infinite side Rimi No 1-Sui Soji No 1! Il! The measurement limiter I switch is a switch that is turned on when the lens is moved to the infinite position.

○F L S W F L G: Abbreviation for infinite side limit switch flag When FLSW (infinite side limit switch) is turned on, the CPU uses FLS to memorize this state.
Set WFLG to “I”.

○FN: Abbreviation of flag indicating motor rotation direction If the rotation direction of the motor is in the infinite direction, FN = 0Nm If the rotation direction of the motor is in the close direction, FN = 10F S F L G
: Abbreviation of Focus 5tart Flag FSFL
G is set to "0" before performing a series of distance measurement and lens driving operations based on this distance measurement. Then, based on the distance measurement and this distance measurement (when the series of L-lens drive operations is performed one or more times, the parameter is set to 1". Therefore, the F
The state of SFLG=1 indicates that at least all lens positions have been adjusted to 1llilu.

○5IGI): Low approximately 5IGD of Signal Data, which indicates whether a long focal length lens is attached or not.
If you can read this, it means that a long focal length lens is attached.

○5NDCTB: A signal that controls the interface on the camera body side.SNDCTB=L sets the interface on the camera body side to the sending state, and the output is 100N.
I) Set the interface on the camera body side to the receiving state with CT B = H.

It is set to I7 before sending CMD (command), and set to H after sending it.

S li N D l I T 11 COIf
T ROL L 8T CAMERΔ 130DY
○S N D CT L Nilens (Shinzuki, who controls the interface by rule, sets the interface on the I/lens side to the sending state with 5 NDCTL = S N I) CT
When L = H, the lens side interface is accepted and the state G becomes difficult.

Set L before sending the command (CMD) and H after sending it.
It is said that

5ENII WITlI C0NTOIIOLL
AT LENSEOL M OT FL G
Flag shown as =1○I=S RON: Command i to turn on the lens side power supply;? 1. 'Jmanl')
The logical value of Lens 5source ON code is (0
00) ○ATEN: Command word (command) that notifies the output of the command code The logical value of the attention code is (
001) ORFD: Command word (command) that notifies the receiving side that preparations for receipt are complete Ready For Data
The logical value of the code is (010) ○Da AV L: A signal that transmits the moving direction DR and amount of the lens (see Figure 6B) Data Available ○DaACK: The receiving side has completed receiving the data. The logical value of the Data Acknowledged code is (100). ○FSWON: The logical value of the FARREST SW ON code is (100).
01*) If FARREST SW OFF *-〇FARR
If EST SW ON, *-1ONSWON:
Command word (command F') to notify the status of NSW NEA
ST S to RR and the logic value of the ION coat is 100 years old)
*-〇1 Juruhachi R11 [3ST If Sl/l is ON *-1 ■ I-MOTCONTEND: Command word (command) 1 that notifies the completion of control of the morph on the lens side, IEIIs MOTOII C0NTOIIOL
L END: logical value ε of r-l-; I: (11),
O) ■ + - p r): Command δ bar (command) to notify the power supply on the lens side to F I will not explain mainly the operations related to sending and receiving the cod between the camera body side and the lens side.
[J3 begins executing the instruction. and CPU3)
sets Baud 1-P26 to High.

However, when SNDCTB=High, Q2B of the interface circuit 12 (see Figure 2) becomes active, and the output of IB becomes floating, so the voltage of VB is applied to the CPU 3 board through Q2B. P
25.

This signal is called 5IGD.

VB is expressed by the following formula.

When setting the relationship RB >> RL, VB = RL - VDDB / (RB + RL) =
RL -VDDB /RB (1) From this, the relationship shown in Table 1 is established.

*1 For normal lenses, leave terminal 29 open.

In other words, the resistance of RL etc. is not increased on the lens side.

When a long focal length lens is attached to the camera body, even if the lens side is not powered on (VDDL = 0), the terminal voltage VL of the resistor RL on the lens side will be VL = Lo.
It becomes w.

CPU3 sets P26 to High and connects V through Q2B.
When reading the voltage of B, if it is Low, it can be determined that a long focal length lens is attached.

(Step 701) FSFLG is set to "'0" before carrying out a series of operations of distance measurement by the focus detection sensor and lens driving based on this distance measurement.

(Step 702) This is a step of determining whether a long focal length lens is attached.

Here, if the 5ICD is read as Low, it means that a long focal length lens is attached, so the process moves to (step 703).

(Step 703) Flag L M does not indicate that a long focal length lens is attached.
Set OTFLG=1.

Step 704) Outputs the LS RON command.

As mentioned above, the LSRON command has a logical value (OOO
) is a command from the camera body side CPU 3 to the lens side to instruct the lens side power to be turned on.

The waveform of this LSRON signal is shown in FIG. 6A.

The LSRON signal changes from Low to High, then goes High for a TON time (usually about 10m5), and then goes to Lay. After the Low state continues for (T+T/3) period and becomes High from Lotv, (2/3)XT
It becomes High for a period.

The CPU receiving the command is 5IGD High to L
5 IGD after T period based on the timing of becoming ow
Read the signal, if this voltage is Low, the logical value is “1”,
Also, if it is High, it is defined as a logical value “0”. LSR
Since the ON command has a logical value (000), it has the waveform A in FIG.

The CPU 3 outputs the LSRON signal when turning on the lens side power supply. If the time T is above, C on the lens side as described later.
It is sufficient to set the time to be a little longer than the time during which the PU 35 executes the read data.

If the time T is not short, the command transmission time will of course be shortened and the command can be transmitted at a high speed, so it is selected to be as short as possible in consideration of the data time. Especially L
The SRON command is characterized by becoming b when isc < 14 i during TON, and this H4gh signal passes through the diode 1"D L on the lens side to the transistor i"r.
1 has been applied. With this signal, transistor T
r 1 becomes conductive and transistor Tr2 is turned on.

When transistor Tr2 turns on, thyristor SCRL
A positive voltage is applied to I, however, SCRL turns on.

A voltage is applied to the input terminal of the D C,/l) C converter, producing a boosted voltage at its output. This voltage is stabilized to a constant voltage (VDDL) by a weight pressure circuit.

The lens side CI) U 35 starts executing the command.

(Step 801) After initializing each 110 on the lens side, the CPU;
5-1) Set 26 to SNDCTL=I-Iigh, and connect 021 of the interface circuit 37 (see Figure 2).
, activate.

(Step 802) The CPU 35 reads the 5ICD signal from the port P25.

If a logical value (000) is read from the waveform shown in FIG. 6A (step 802), it is determined in step 803 that it is an LSRON command and the process proceeds to the next step.

(Step 804) (Step 805) Lens side (
7) The CPU 35 waits until the next (ATTENCMD) attention command is input.

(Step 706) After transmitting the LSRON command in step 704, the CPU 3 on the camera side checks whether the LSW is on in this step.

(Step 707) to (Step 7o9) If it is determined in step 706 that the LSW is on, it is determined in this step which limit switch is on.

(Step 710) - (Step 711) F in that state
Cent LAG.

(Step 712) If LSW is off, NLSWFLG and NLSW
Clear both FI-G.

(Step 713) Shift the lens using the focus detection sensor 6 on the body side.
Find the exponent amount N.

(Step 714) Based on the distance measurement result in the step, the FLG is set without indicating the rotation direction of the lens morph.

(Step 715) If the focus is not automatic focus adjustment (a mode in which the lens is manually adjusted by referring to the display)
Determine whether it is the J focus adjustment mode.

If the mode is automatic focus adjustment, the process advances to step 716.

(Steps 716 to 723) Since these steps are not the gist of the present application, they will be explained together later. After executing these steps, step 72
Suppose you proceed to step 4.

(Step 724) Since the spherical focal lens is attached, L M OT F
It is cented at LG=1.

If LMOTFLG=0, the CPU on the camera body side
3, the adjustment of a normal autofocus lens that is not a long focus lens is performed (steps 730 to 751). Since the adjustment of this part is not the gist of the present invention, it will be described later.

If LMOTFLG is set to 1, the lens smoke control mode program (steps 760 to 771)
Proceed towards.

(Step 760) If FLSWFLG and NLSWFLG are not set (when the lens is not at the travel limit), step 76
Proceed to step 2.

(Step 762) Here, the CPU 3 sends the above-mentioned attention command (AT
TENCMD) (001) is output.

In this case, CPU3 sets port P26 to Low (5N).
Set DCTB=L, activate QIB, and then output ATTENCMD to port 1-P25.

And suddenly, SNDCTB = H4gh.

(Step 763) The Karaboti side receives the RD from the CPU 35 on the lens side.
Wait at the data leave to receive C.

At this time, the interface circuit 12 on the camera body side is set to input mode.

(Steps 804-805) Meanwhile, the CPU 35 on the current side is waiting at this step,
Load data from Karaboti.

Check if it is ΔT i"ENCMD (001) and check if it is ΔT i" IENCMD (001) in step 805.
).

(), RANOFU" 806) Lens side CI) U 35 sends 1 FI) CM D to ATTENCMD.

And just P26 boat output 5NDCT13
=II igb and sets the interface circuit 37 to input mode.

(Steps 763-764) The camera-side CPU 3 waits for a signal from the lens side (010) (7) RFDC
After loading the MD, proceed to the next step.

(Step 765) Set SNDCTB to Lo- and output DaAVLCMD and a data out signal.

This command and data out signal are It consists of a command "011" and a data section.

The first bit of the data portion is DR.

If DR=O, advance the lens towards close range and DR=1
Then, it is defined as proceeding in the infinite direction.

If the 11 bits following this bit are
The drive amount N on the lens side obtained in step 3 (corresponding to the number of pulse outputs of the encoder 40) is expressed in binary, and the first via t□ side is H.
igh n1ble, the last bit is Lownib
Define and arrange so that it is ble.

A parity bit is added at the end to increase the reliability of data transmission. The parity bit can be odd or even parity.

After outputting this command and data, proceed to the next step.

(Stage, 767-768) On the Karaboti side, set the lens to 5NDCTB-“High (D aA CK CM D from the beginning)
(Acknowledged command).

(Steps 807-809) The CPU 35 on the lens side waits at (Steps 807-808) and reads D a AV L CM D.

Then (step 809) the data output is 3;
8 L7j included.

This dataau I/Puno 1- contains information including the above-mentioned N.

(Steps 810 and 811) Check pari Ly of the data read in this step and output DaACKCMD. par i
If ERROR occurs as a result of the jy check, jump to the above-mentioned (step 806) and perform the RFDC again.
Output the MD to the camera side and output the CP on the camera body side.
Request U 3.

(Step 812) In this step, the command read in (Step 809) is analyzed, and if the binary from the command top bit to 3 bits is "0", 1", the bits below DR are decoded and the direction and drive amount are data is obtained and the process proceeds to step 813.

(Steps 813 to 843) These steps are steps in which the lens-side CPU 35 drives the lens-side motor 20 based on the data on the direction and drive amount.

The amount of lens extension is determined from the encoder 40 to the CPU 35.
When the control specified by the program is completed, the process moves to the next step 844).

The details of these steps are the same as the control on the camera body side, so they will be described in detail later.

(Step 844) When the control specified by the program is completed, a lens motor control end command LMOTCONTENDCMD (1110) indicating completion of lens side motor control is sent to the camera side CPU 3. Thereafter, the process returns to (step 804), and the CPU 35 waits for one step while accepting the next command.

(Steps 771 to 790) On the Karabody side, in this step, the LMO]”C
Wait for ONTBNDCMD (I L 1 0) and if this signal is confirmed, jump to (step 706), determine the distance measurement error, and if the predetermined control is performed,
The process advances to step 790, where necessary controls for camera photography such as automatic exposure J*I', I\, etc. are performed.

At the end of this necessary control (at the end of shooting), the Karaboti side performs a step not shown in the figure, which will be described later.
Output.

If the predetermined control is not performed, based on the new N (
Step 724) and subsequent steps described above are executed.

[(/ns(ill power down)]

In order to reduce power dissipation, the camera side CPU 3 executes the lens power down command after the camera side has finished shooting.
Output PDCMD (1 1 1 1).

The CPU 35 on the lens side reads this LPDCMD (steps 804 to 809).

Analyze step 8 with command analysis (step 812)
Proceed to step 50).

(Step 850), the CPU 35 sets P24 to High. Transistor Tr3 turns on and its collector voltage drops to LO-.

As a result, a negative voltage is applied to the anode of the thyristor SCRL, the thyristor SCRL is turned off, the transistor Tr2 is also cut off, and the power supply on the lens side is turned off.

It is expected that neither the first Lurie nor the second release will be operated even after a certain period of time has passed after the exposure control is completed.

In this case as well, it is necessary to cut off the power on the lens side. After completing the exposure control, the CPU 3 on the camera side, as described above,
LPDCMD (1 111) is output after a certain period of time has elapsed.

In this case as well, the power on the lens side is turned off in the same manner as described above.

To turn on the power to the lens side again, use the CPU 3 on the camera side.
It is sufficient to apply I-S RON CM D to the connection terminals 27 and 29 of the CPU 35.

In this way, the power on/off control on the lens side can be freely controlled by the CPU 3 on the camera side.

[Processing related to LSW on the car body side Fig. 3C] (Step 760) LSWF LG= 1 (Limit 5w1tch
is on), steps 780 to 785 are executed.

If NLSWFLG-1, FN = 1, the limit switch on the close side is turned on and the limit switch on the close side will change if driven to the close side, so the display indicating the limit on the close side is displayed in (step 784) after going through steps 780-782. Turn it on.

N L S W F i, G = O, F N =
A state of 0 means that the limit switch on the infinite side is on and driven toward the infinite side (step 780-7).
81) and then (step 783), the display indicating the limit on the infinity side is turned on.

NLSWFLG=1, FN=O state and NLSWF
Since the state of LG=0 and FN=1 is the case where you want to drive to the opposite side of the limit/throat switch that is on, in (step 785), set LSWFLG to -0 (step 762).
).

(Steps 762 to 768) The CPU 3 waits until it receives a control completion signal for the lens-side motor.

[Processing of glue on the lens side, etc.] As shown in Figure 4, if a command is received from the camera side, the lens side C
The PU 35 executes (steps 8.7 to 812), analyzes the command, and proceeds to the lens motor control mode (step 813).

(Step 813) The CPU 35 checks whether the limit switch is on and
If it is on, the process advances to step 815.

(Steps 815 to 818) Check whether the near or infinite mint switch is on.

(Step 818) If the close limit switch is on, NLSWFLG=
(Steps 819 to 8)
The process proceeds to step 40) for determination, and then proceeds to (step 843). (
The DR is decoded in the data received in step 809), and if DR=O, it is a command to rotate in the closest direction, so the process of setting 1='N=1 at the time of decoding is executed in advance. put.

(Step 843) Since FN=1, the process advances to (step 844).

Output the remote control signal and step 80
Jump to 4.

(Step 804) Waits for the next ATTENCMD (attention command) from the camera side.

(Step 841) If NLSWFLG=0, then (Step 841) FN=
1 is checked, and if the process continues in the infinite direction (step 844), sends LMOTCNTENDCMD (lens motor control end command) to the camera side (step 804) and waits for ATTENCMD (attention command).

If NLSWFLG = 0 and FN = 1, and NLSWFLG = 1 and FN = 0, rotation in the opposite direction to the direction of the limit switch that is on is instructed (Step 8
42), LSWFLG is set to O (step 820).

[Explanation of program related to distance measurement and in-focus point determination FIG. 3A] (Step 700) The power is turned on, and the CPU 3 starts executing commands.

(Step 700 1) Set FSFLAG=0 (!).

(Step 706) Check whether the limit switch LSW is in the on state.

(Step 712) If both NSW and FSW are off,
Cent N5WFLG=0, FSWFLG=0.

(Step 713) /l! +] In the distance routine, the lens extension lJl to the in-focus point is calculated, and the corresponding data on the number of pulses (N) of the bottom coupler of the encoder and the amount of motor driving force are obtained.

(), Step 7] 4) One stroke! ! Set II to 1"1' or 1 (motor drive direction flux) depending on whether the moving direction is the infinite direction or the close direction.

(Step 715) Determine whether or not it is a power source.
reactor. If it is AF mode 1 (step 716), proceed to step 716.
.

(So, U-) B 7'1fi) 1" SF 1. G is cPU when the second release is on
At step 700-1, the power is turned on and the program starts operating.
2) ゛So, F S F L at each step.
If C is 1°, then 1, after the 1st Lullies; t It is a shame that the series of operations of distance measurement and lens driving were performed more than once before this point.

In this case, the focus width of the lens is not widened and the routine jumps to step 720.

If FSFLG is 0'' in (step 716), the process advances to (step 717).

(Step 717) Check the shirt release (second release) SW. When the shirt release SW is turned on, it is assumed that the photographer wants to take a picture quickly (if the camera is in focus, he wants to release the shutter), and the process proceeds to step 719.

(Step 719) In this step, the tolerances are corrected.

The error No. that is always set takes into consideration the depth of field or depth of focus calculated from the aperture value information of the lens mentioned above.
Add the error for depth to .

It is preferable that this addition be made slightly smaller than the actual depth of field.

For example, the addition amount may be the same for F4 and above, and the same value may be used for F5.6 and F16.

If the shirt release SW is not turned on in (step 717), the focusing operation can be performed using a predetermined focusing width that corresponds to the accuracy at the aperture value (step 718).
Then, the above-mentioned FSFLG is set to 1 in order to prepare for the next focusing operation.

(Step 720) If L S W F L G = 0 (Step 7
Proceed to 21).

(Step 721) In this step, 5
Decide whether it is worth it or not.

If N is less than or equal to the allowable range NO, the process proceeds to step 790 to proceed to the exposure adjustment mode.

Add 31 of the tolerance range (error) with t (step 723)
If 1 or 1 is performed, the above No. is the value obtained by adding the error for the depth to the No. j'j' of (step 790).
;, '+Output adjustment--The probability of proceeding to shutter release increases.

N Z, ,: No is satisfied and enters the AE operation mode (step 790), and after completing a series of operations, 5t
Since the process returns to a (step 700), (step 721)
N shown in The value of is set to the initial state of the focusing width (accuracy) in the state of the aperture value.

If N is not less than the allowable range NO, the process proceeds to the next step (step 724).

[Explanation of the program that drives the lens with the motor on the camera body side (Figure 3B)) The second program is not the gist of the present invention, but it is almost the same as the program that drives the lens with the motor on the lens side. I'll explain first.

(Step 730) If LSWFLG=(l), proceed to (step 731).

(Step 731) In this step, L
Turn on the ED.

(Step 732) In this step, it is determined whether the motor is fully driven or slightly driven by comparing the amount of extension (N) to the focal position with a constant (Nm).

When the motor is fully driven, a continuous current is supplied to the motor, as shown in FIG. 8, and when the motor is slightly driven, an intermittent current is supplied.

If the amount of feeding is large and (N≧Nm) is established, the process proceeds to fully driving the motor (steer knob 733).

(Step 733) Use this knob to issue a command to fully drive the motor.

(Step 734) Considering the inertia of the motor, the brake is applied when the remaining number of pulses Nν becomes equal to a constant (Nstop), including the overrun from when the motor is braked until it comes to a complete stop. put on.

The remaining number of pulses Nv is determined by iq in step 713.
This is the number obtained by subtracting the number of output pulses from the encoder from N.

If Nv>N5top, the process advances to step 735.

(Step 735) This step is a step to determine whether the LSW is on or not.

If the LSW is not on, (step 733) - (step 734) (N v > N5top) -" (
A loop of steps 733)-(step 734) is executed to continue rotating the motor.

When Nv=Nstop is established in the loop (Step.

Proceed to step 736).

(Step 736) Turn off the motor drive and apply the brakes at the same time.

After a certain period of time has elapsed, the process proceeds to step 737.

(Step 737) Turn off the LED of the encoder and proceed as shown in FIG. 3A (Step 70
Returning to step 6), the focus determination program described above is executed.

If (N≧N m ) does not hold in step 732, the process proceeds to step 738 to finely drive the motor.

(Step 738) The motor is driven by an intermittent pulse current to start fine driving. and (step 739) - (step 74
0) → (step 738), the loop of (step 73
9) or (step 740) continues until the condition 'l is satisfied.

(Step 739) The lens is converged to the focal point by the fine driving loop, and N v
If ≦No, it means that focus matching has been established, and the process proceeds to step 736.

(Step 736) - (Step 737)
) The LED of the encoder is turned off, and the process returns to step 7 (IG) of FIG. 3, where the focus determination program described above is executed.

1j; 1 mentioned above is the case where the limit switch is not turned on while driving the lens, but (step 713
) The dust switch may be turned on by driving the motor based on N obtained in ).The following two cases are examples of this.

(2) In (step 739), Nv≦N is not established, and in (step 740), LSW is turned on.

(2) In (step 734), N v = N 5top is not established, and in (step 735), LSW ON is established.

Power! (Assume that the FLSW is turned on while the adjustment is being made in the limit direction.

In each of the above cases, the process proceeds to step 741).

(Step 741) Stop motor drive.

(Step 742) L S W F L G = 1 cent.

(Step 743) At this point, check which NLSW is turned on.

Since the control is on the infinite side, the information that FLSW is on is connected, so proceed to (steer knob 764).

(Step 764) Set NLSWFLG=OXFLSWFLC=1.

(Step 746) Slightly rotate the motor in the opposite direction (NR
).

This reverse direction rotation control is performed as described above (step 73).
8) Use the loop of - (step 739) → (step 740) - (step 738), and in (step 764) N L S W F L G - ○, F
On the condition that L S W F+-G = 1, the above (Ste knob 739) is Nb≧NR(y>
1:111 step and step '140)
is the step of returning to the above-mentioned step (if 'l is not added to 1flI5, remove the knob 738). However, Nb is the number of output pulses of the encoder after starting the reverse rotation.

(Slur, P738→739-740-738) When the predetermined reversal is completed and N b ≧NR is satisfied in the loop, the process proceeds to step 736.

+iii mentioned (step 736) - (step 737
) The LIE D of the encoder 1 is turned off, and the process returns to step 706 in FIG. 3, where the focus determination program described above is executed.

[Explanation of the 1-column that drives the lens with the motor on the lens side (Figure 4 B))
Since this program is the same as the program for driving the lens, the explanation will be omitted.

As explained above, the present invention uses one bidirectional electric signal line for the interface between the camera side and the lens side,
■ Turning the power on the lens side on and off ■ CP on the camera body side
The configuration is such that signals can be transferred between the U and the CPU on the lens side.

Therefore, it has become possible to control long focal length lenses with a simple connection mechanism.

[Brief explanation of drawings]

FIG. 1 is a system block diagram of an automatic focus control device for an interchangeable lens camera according to the present invention. FIG. 2 is a circuit diagram showing an embodiment of an automatic focus control device for an interchangeable lens camera according to the present invention. FIG. 3 is a flowchart showing the configuration of the CPU on the camera body side. FIG. 4 is a flowchart showing the configuration of the CPU on the lens side. FIG. 5 is a flowchart of the automatic focus control device according to the present invention (3rd
FIG. FIG. 6 is a waveform diagram showing command waveforms. FIG. 7 is a graph for explaining the constants used in the control shown in the flowchart. FIG. 8 is a waveform diagram showing electric/Jli waveforms when the motor is fully driven and when the motor is slightly driven. 1...Cara body side power supply 2...Cara body side power hold circuit; 3...
Camera body side CPU 4... Motor 1-541 circuit 5... Analog digital converter 6... Focus detection sensor 7... Camera body side motor 8, 9. 10... Gear train 11... Coupler I2... Camera body side interface circuit 13.
... Reflection mirror + 4 ... Main mirror 15 ... Lens 16 ...
- Helicoid 17, I8.19...Gear train 20...Camera body side drive motor 21...Release button 22.23-...Release contact piece 27.29...Connection terminal 33...Lens Side power supply 34... Cara body side power hold circuit 35...
・Lens side CPU 36...Motor drive circuit 37...Lens side interface circuit 38...Preamplifier 39...Encoder plate 40...Lens side encoder 50.51...Connection terminal 52...Camera body side encoder

Claims (1)

[Claims] Start-up sensor, focus detection sensor, control Karaboti side CI) U, controlled by the CPU (+: r ”
An interface circuit for the two receivers is provided on the camera body side, and a lens side inkcup is connected to the interface circuit with a connecting wire.
32B and an encoder that detects 32B and inputs C. and a lens provided with a terminal that allows the Karabotity side to recognize that the lens has a lens drive motor. ．．・When it is determined that the camera body is in the camera body, the interface circuit on the camera body side is set to the output mode, and a command is sent to turn on the I/Answer power supply, and control data regarding the direction and amount of movement of the lens is sent from the focus detection sensor. is read and judged, and if it is not within the allowable range, a data sending state is established, the power hold circuit holds the lens side power supply according to the command, and the lens side CPU sets the lens side interface circuit to reception mode. , read the control data,
The motor drive circuit, the lens drive motor, and the encoder that detects and inputs the actual lens movement amount are operated, and after the lens drive based on the control data is completed, the lens side interface circuit is set to the transmission mode and the lens side is transferred to the camera body side. The camera body side CPU operates the focus detection sensor, rereads the control data regarding the direction and amount of movement of the lens, and checks if the data is within the allowable range. An automatic focus control device for an interchangeable lens camera that is configured to determine whether or not the lens exists, and if it is within an allowable range, to proceed to the next control.