JPS62264032A - Distance information output device of camera - Google Patents

Abstract

PURPOSE:To obtain an absolute distance of high precision by a simple operation of the counted output corresponding to a relative distance by providing a counting means, a reset means, a storage means, and an operating means to constitute a device as specified. CONSTITUTION:A counting means 1 which counts the relative distance in accordance with the motion of a photographic lens and a storage means 2 where peculiar data of the photographic lens required for conversion of the counted value of the counting means 1 to the absolute distance is stored are provided. Peculiar data stored in the storage means 2 and the counted value from the counting means 1 are operated in an operating means 4 to calculate the absolute distance. When the photographic lens reaches a reference position, the counted value of the counting means 1 is reset by a reset means 4. Thus, the counted output corresponding to the relative distance is subjected to the simple operation to obtain the absolute distance with a high precision in the constitution adapted to a system camera.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a camera distance information output device, more specifically,
The present invention relates to a distance information output device that can obtain absolute distance information for autofocus driving, etc. in a camera.

[Prior Art] Lens distance information output includes absolute distance information and relative distance information. Absolute distance information in autofocus is something that outputs a signal that corresponds to the distance itself, and relative distance information is information about how far the object deviates from the current distance. Relative distance information is
For example, distance information can be output using only comb-teeth electrodes, which has the advantage of simplifying the configuration as a distance information output device for interchangeable lenses, but for single-lens reflex cameras as system cameras, it is better to use absolute distance information. becomes convenient.

As a means of obtaining absolute distance information,
An absolute distance encoder that emits a bit gray code digital signal (see Japanese Unexamined Patent Publication No. 50-67650); A device in which detection is performed using a detection element (see Japanese Patent Application Laid-Open No. 108828/1983) is known. Both of the known means of ■ and ■,
Absolute distance detection is devised by using the output obtained by converting the movement of the lens distance ring, that is, by linking members directly to the distance ring.

[Problems to be solved by the invention] 1 However, the publicly known means of ■ and ■ above,
Since it is necessary to provide an absolute distance encoder, a detection element, etc. that occupy a relatively large space for each interchangeable lens barrel, the interchangeable lens barrel becomes large and expensive, and this is not desirable for users in terms of systematization. do not have.

The applicant first generated an address signal from a pulse generating means provided inside the interchangeable lens barrel, counted this signal using a CPU (processing unit) inside the interchangeable lens, and compared it with a distance code table to determine the absolute address signal. He proposed a device for calculating distance (Japanese Patent Application No. 134800/1982). Since this device uses a distance code table, it is necessary to provide a memory for the code table.

In view of these points, it is an object of the present invention to provide distance information for a camera that is suitable for a system camera and that obtains absolute distances with high accuracy by performing simple calculations on counting outputs according to relative distances. The purpose is to provide an output device.

[Means and effects for solving the problems] As shown in FIG. 1, the distance information output device for a camera according to the present invention is provided with a counting means 1 for counting the relative distance according to the movement of the photographing lens. In addition, a storage means 2 is provided for storing unique data of the photographing lens (absolute distance count, etc.) necessary for converting the count value of the counting means 1 into an absolute distance. The unique data stored in the above-mentioned counting means 1 and the count value from the counting means 1 are calculated by the calculating means 3 to calculate the absolute distance. When the photographing lens reaches the reference position, the count value of the counting means 1 is reset by the resetting means 4.

[Example] Hereinafter, an example in which the present invention is applied to an interchangeable lens camera having an autofocus (hereinafter abbreviated as AF) function will be described.

FIG. 2 is an overall block diagram mainly showing the power supply of the camera system to which the present invention is applied. Power battery 1
1 voltage vCc is DC/D when the power switch 12 is opened.
The voltage is boosted by the C converter 13, and the voltage between the lines g I is set to a constant voltage vDD of 0' 1 . Main CPU14 between lines 1o and 111
, Bipolar Road 15. Bipolar II circuit 16, strobe control circuit 17. A lens data circuit 18 and a data pack circuit 19 are connected, and a bipolar circuit 15
Power supply control is performed by signals from the power control circuit of the main CPU, and
Power supply control for the data pack circuit 19 is performed by a power control signal from the bipolar circuit 5.

Focus sensor 20. A/D converter 21. AF CPU
The AP block consisting of 22 is a power supply control transistor 2
Line g through 3. 9g1, and power supply control for this AF block is controlled by the main CPU 14.
This is done by controlling the transistor 23 on and off using a signal from the AF power control circuit.

The AF river PU 22 is a circuit for performing AF algorithm calculations, and is connected to an AF display circuit 24 that displays in-focus/out-of-focus. The main CPU 14 is a circuit for controlling sequences of the entire camera such as winding, rewinding, and exposure sequences, and is connected to a display circuit 25 for displaying other than the above-mentioned focus display. Bipolar ■Circuit 1
Reference numeral 5 denotes a circuit including various drivers necessary for camera sequences such as winding and rewinding motor control, lens drive, and shutter control, and is connected to an AF motor drive circuit 26, an AF auxiliary light circuit 27, and the like. The bipolar 1 circuit 16 is a circuit mainly responsible for photometry, and has a photometry element 28. The strobe control circuit 17 is for controlling the light emission of a built-in or external strobe 29. The lens data circuit 18 has an AF that differs for each interchangeable lens.

This is a circuit that stores unique lens data necessary for all light and other camera control. This lens data circuit 1
Among the lens data contained in Section 8, the data necessary for AF includes the lens magnification coefficient (zoom coefficient), macro identification signal, and absolute distance coefficients a and b.

These include power focus duty coefficient, AF accuracy threshold ETh, lens movement direction, and aperture F value.

The bipolar ■ circuit 15 monitors the state of the power supply voltage vDD, and when the power supply voltage drops below the specified voltage, it sends a system reset signal to the main CPU 14 to supply power to the bipolar ■ circuit 15 to data pack circuit 19, and Focus sensor 20° A/D converter 21 and A
The power supply to the AP block consisting of the FJTI CPU 22 is cut off. Power is supplied to the main CPU 14 even if the voltage is below the specified voltage.

FIG. 3 is a system diagram showing the transmission and reception of signals centered around the AF block. The AF CPU 22 and the main CPU 14 transmit and receive data via a serial communication line, and the direction of the communication is controlled by a serial control line. . The contents of this communication include unique lens data within the lens data circuit 18 and absolute distance information. In addition, from the main CPU 14, AFJ
The camera mode (AF single mode/AF sequence mode/power focus (hereinafter referred to as P
(abbreviated as F) mode/other mode) information is decoded through the model line.

Furthermore, A from the main CPU 14 to the AP CPU 22
FENA (AF enable) signal is AF.

This is a signal that controls the start and stop of each mode of the PF, and is transmitted from the AP CPU 22 to the main CPU.
EOFAF (end of AF) signal to 14 is AP,
This is a signal issued at the end of operation in PF mode to permit transition to the exposure sequence.

In addition, the bipolar circuit 15 decodes the AF motor control line signal from the AF CPU 22, and
Drives the F motor drive circuit 26. The AF motor (lens drive motor) is driven by the output of the AF motor drive circuit 26.
31 rotates, the slits 32 provided at equal intervals in the rotating member of the lens barrel rotate, and a photointerrupter 33 is formed in which a light emitting part 33a and a light receiving part 33b are arranged facing each other across the path of the slits 32. Count the slits 32. That is, the slit 32 and the photo interrupter 33
constitutes the lens movement amount detection section 34, and the address signal (count signal of the slit 32) issued from the movement amount detection section 34 is waveform-shaped and taken into the AFJIC CPU 22.

The sub lamp (hereinafter abbreviated as S lamp) signal sent from the AFm CPU 22 to the bipolar ■ circuit 15 is a signal that controls the AF auxiliary light circuit 27, and when the subject is low light (low brightness) and low contrast, the S lamp 2 is sent to the bipolar circuit 15.
Turn on 7a.

The AF display circuit 24 connected to the AF CPU 22 includes a focus display LED (light emitting diode) 2 that lights up when in focus.
4a and an LED 2 for displaying failure to focus, which lights up when it is impossible to focus.
4b. In addition, this AF CPU 22 has a clock oscillation? jr35. Reset capacitor 3
6 is connected.

Further, the AF CPU 22 and the A/D converter 21 exchange data via a pass line, and the direction of the data transmission is controlled by a pass line control signal. A sensor switching signal and a system clock signal are sent from the AF CPU 22 to the A/D converter 21. The A/D converter 21 is, for example, a C
A CCD drive clock signal and a CCD control signal are sent to the focus sensor 20 consisting of a CD, and the focus sensor 20
Read the D output and display the read analog value on the CCD.
The output is digitally converted and sent to the AP CPU 22.

Next, a flowchart of the program operation of the microcomputer centered on the AF block shown in FIG. 3 of the camera having the distance information output device of the present invention will be described. The AF block is connected to the main CP as shown in Figure 2.
By activating the AF power control circuit U14, the transistor 23 is turned on and the power supply voltage v
DD is supplied, thereby beginning execution of the power-on reset routine shown in FIG.

When this power-on reset routine is started, first, the AF block drive circuit is initialized in the subroutine 110 (Initialize). Specifically, the AF display circuit 24°, the AF motor drive circuit 26, the AP auxiliary light circuit 27, etc. are turned off, and the main CPU 1
Initialization of the serial communication line with 4 is performed.

Next, in the <mode read> subroutine, the main C
After reading the model line signal (mode signal) from the PU 14 and determining what lens drive mode to execute, a certain period of time passes through the ``timer'' routine, and then the mode is read through the ``mode read'' routine again. Reading the switching point. Then, the process returns to the first mode Φread until the mode switching is completed. mode Φ
The reason why the read> subroutine is passed through twice with the timer in between is to prevent reading errors at the time of mode switching.

When the mode has been reliably switched and the mode before and after the switch is the same, the mode after the switch is read and a transition is made to the subroutine for each mode. That is, the lens drive modes include lens reset>, <
PF (power focus)>, <AFS IN (A
There are the following modes: AF SEQ (AP sequence) and AFSEQ (AP sequence). When one of these modes is selected, the subroutine of the selected mode is executed, and then the above (I10 initialization) routine is executed. Return to

Lens Reset>, <PF>, <AFSIN>.

When none of the <AFSEQ> modes are selected and the <Other> mode is selected, this is treated as mere noise, and the above I10 initialization is performed in the <Timer> routine after a certain period of time. Return to

Here, the operation of the lens reset mode is to forcibly retract the lens to the infinity (oo) position, thereby changing the relative distance signal, that is, the 1llll distance output signal output from the focus sensor 20. This is an initialization operation for replacing the pulse movement number from the position at infinity (oo) with the number of pulses and converting it into an absolute distance signal, that is, an operation for clearing the absolute distance counter. When "lens reset" is selected, the I10 initialization operation is returned to, for example, after 5 ms has passed after the absolute distance counter is cleared.

Furthermore, the <PF> mode is a mode in which the distance ring of the lens is driven not manually but by the lens drive motor 31, and the focusing operation of the lens is performed using manual focusing or focus aid. More specifically, the PFUP (up) operation switch SW, which will be described later.

Turn on operation switch SW2 for PFDN (down).

When the lens is turned off, the lens is extended and retracted. Also, the operation of <AFSIN> mode is as follows:
This is a one-shot AF operation, and the focus is locked after the AF operation on the subject. Furthermore, <AF
SEQ> mode is continuous AP, and in this mode,
As long as the first stage of the release button continues to be operated, the AF operation will be performed continuously.

By the way, as operation switches for each mode of lens drive, four operation switches sw-5w4 are used, as shown in Table 1 below.

■ Table 1 (*Either “ON” or “OF” is acceptable) No. 1 shown in Table 1 above. Second operation switch SWl.

SW2 is commonly used in AF mode and PF mode, and the third operation switch SW3 is used for AF when it is off.
mode, PF mode is selected when it is on. 1st in AF mode. When the second operation switch SW and SW2 are both off, the lens reset mode is entered, and when both are on, the AFSEQ mode is entered, and the first operation switch SW
l is off.

When the second operation switch SW2 is on, the AFSIN mode is entered. 1st in PF mode. Second operation switch SW
1. When both SW2 are off or on, it is in stop mode, and when the first operation switch SWl is on, it is in PFUP (up) mode in which the motor rotates the distance #I ring toward the short distance side and extends the lens. ,
When the second operation switch SW2 is on, the lens enters the PFDN (down) mode in which the distance ring is rotated toward the long distance side to retract the lens. Further, the fourth operation switch Sv4 is A
There is no change whether it is on or off in any of the P modes, or whether it is on or off in the stop mode of the PF modes, but in the PF mode. When it is on, it is in HI (high speed) mode, and the lens drive motor 31 rotates at high speed to perform coarse movement of the distance ring. When it is off, it is in LO (low speed) mode, and the motor 31 (see Figure 3) rotates at low speed. A slight movement of the distance ring takes place.

Next, we will explain the operation of each lens drive mode in Figures 5 to 9.
This will be explained using the flowchart shown in the figure.

First, when the <AFSIN> mode is selected, the <AFSIN> routine shown in FIG. 5 is executed, and it is detected whether the AFENA signal from the main CPU 14 is at the "H" level (active). do. With the first operation of the release button, the AFENA signal becomes active, AF operation is started, and the <AFSIN2> subroutine is called. However, the second operation of the release button is accepted when the AF operation is completed, a focused state is obtained, and the exposure sequence is started. <AF
SIN2>, as described later, the C of the focus sensor 20
CD integration, distance measurement output calculation, lens driving, etc. are performed. The focus is the result of the AF operation of <AFS I N2 >.

Out of focus is displayed by monitoring the AP status flag after the <AFSIN2> operation. The F status flag is a low contrast flag (a flag set to "1" when the subject is in low contrast, hereinafter abbreviated as LC flag), a movement flag (when the subject is moving)
The flag that is set to 1" (hereinafter abbreviated as the M flag) and the closest approach flag (the flag that is set to 1' when the lens is extended beyond the closest distance, hereinafter abbreviated as the N flag). Focusing is possible when any of these flags is "0", and focusing is impossible if any of the above flags is set, so go to the results of monitoring the F status flags. If the AF status flag is "0", the LED 24a of the AF display circuit 24 indicates that the camera is in focus, and if the AP status flag is not "0", the LED 24b indicates that the camera is unable to focus. . If in focus, E
The OFAF signal is issued, the AF operation ends, and the main C
The PU 14 enters a state of waiting for the second operation of the release button, that is, the start of the exposure sequence. In other words, once focusing is completed, even if the AFENA signal is active, further lens operation is prohibited and the focus indicator LED
24a remains lit and the focus is locked. The AFENA signal from the main CPU 14 is “L”
” level (inactive), the process returns to the initial operation of the power-on reset flow shown in FIG.

While operating in the above <AFSIN> mode, <AFSIN2>
The program operation of the subroutine > is performed as shown in FIG. First, in order to compare the previous distance measurement calculation value (the previous output pulse of the focus sensor 20) and the current distance measurement calculation value (the current output pulse of the focus sensor 20),
The TRY (retry) flag is cleared, and the maximum number of distances of 7I-1 in a series of AF operations is set in the AF small loop counter. Thereafter, the maximum value of the CCD integration time is set in the ITIME register so that CCD 1i minutes is reliably performed at a certain brightness or higher. And A
The F status flag is cleared and the S lamp flag is also cleared. The operations in the flow up to this point complete the initialization operation before starting AF.

Thereafter, the lens read> routine is called, and after each lens data stored in the lens data circuit 18 is read out, the <AF> routine for distance measurement is called. In this <AF> subroutine, it is determined whether or not it is necessary to light the S lamp 27a during CCD integration. If it is necessary to light the S lamp 27a, the S lamp flag is set, and if it is not necessary, it is cleared. Ru. Further, a low light flag (a flag set to 1" when the subject is in low light, hereinafter abbreviated as LL flag) and LC flag are set or cleared.

゛ Now, after <AF> distance measurement operation, LL flag, LC
When all flags are cleared, the routine ``Pulse'' is called and the amount of lens drive is calculated. That is, in the routine of <this pulse>, the above <AF
In order to convert the AF (Al1 distance) calculation output value obtained in the above operation into a distance movement amount for each interchangeable lens, information such as the magnification coefficient is read from the lens data circuit 18, and the read magnification coefficient and the like are read from the lens data circuit 18. The number of pulses (address signals) corresponding to the amount of movement to the in-focus point is calculated from the AF calculation output value.

After that, the AF calculation output value (ERROR) is compared with the AP accuracy threshold ETh read from the lens data circuit 18, and the AF calculation output value (ERROR) is compared with the AP accuracy threshold ETh read from the lens data circuit 18.
) is larger than the AF accuracy threshold ETh, then
Proceed to (2) to determine the RETRY flag. In the first AF fishing operation, since the RETRY flag is "O", the number of drive pulses is saved after the RETRY flag is set. And after the second mouth, A
Since the RETRY flag is set in P operation,
The current number of drive pulses and the previous number of drive pulses are compared. At this time, if the number of pulses this time is smaller by the amount of movement than the number of pulses last time, it means that the lens drive has approached the in-focus point, so the next lens drive will focus even more on one point. It was decided that the pulse would be approaching, so the current pulse was saved in place of the previous pulse, and <MD
RIVAF> routine is called to drive the lens.

The purpose of comparing the previous pulse and the current pulse is to
The purpose is to prevent divergent behavior of the entire sequence. Possible ways to compare the two are (current pulse number); (previous pulse number X 0.5), or (current pulse number): (previous pulse number X 1.5). If the AF sequence system is likely to be in a divergent state, it is possible to perform AF fishing operation while the subject is moving, so in this case,
Immediately stop lens driving, set the M flag to prevent wasted AP operation, proceed to ■, and perform <5 DI described later.
SCNT>, <CALD I ST> routines are called.

After the lens is driven by <MDRIVAF>, the AF fishing operation apE distance count value 1 set in the AF small loop counter is subtracted. And as a result, A
If the value of the F small loop counter is not 0, the IT
Set the integration time in the IME register, and then set the AFE
The NA signal is active (that is, the first stage 11 of the release button
When the operation is on), it returns to 0 for the next AF fishing operation. In this way, each time the AP operation between 0 and 0 is repeated, the value of the AP small loop counter is decremented once, gradually approaching the in-focus point, until the value of the F loop counter reaches 0. Even if it becomes AP
If the calculated output value (ERROR) does not become smaller than the AF accuracy threshold ETh, it is determined that focusing is impossible and the M flag is set.

When the result of the AF operation between O and 0 becomes ERROR<ETh, that is, when the AP calculation output value (ERROR) falls within the focus error range, the AF status flag is cleared to indicate that the in-focus state has been reached. , <5DISCNT
>, calls the <CALDI ST> routine.

Here, after the <AF> operation described above, if the LL flag or LC flag is set, the state of the S lamp flag is tested. At this time, if the S lamp flag had been set to "11" in advance, the low light and low contrast state would have occurred even though the S lamp 27a was lit during the integration operation for AF. Therefore, in this case, the LC flag is tested again, and in the case of low contrast, only the lens NF (unable to focus) routine is called to actively display that the lens is unable to focus. In this routine, the lens is first extended to the closest position, and then moved to infinity (oo).
The user is actively notified of the inability to focus by moving the lens significantly. Note that the lens operation indicating inability to focus may be an operation of moving the lens from the infinite (oo) position to the closest position. In addition, in this lens NF>, an absolute distance counter is used to save the number of drive pulses (number of moving address signals) from the infinity (oo) position of the lens distance ring by hitting the infinity (oe+) position. is initialized. If the contrast is not low, it means that the AF calculation was performed even though the light was low, so in this case, the value returns to 0.

Also, if the S lamp flag was cleared in advance, it means that the S lamp 27a was previously off, so if the LL flag or LC flag is set, set the S lamp flag. , proceed to [F].

Therefore, the S lamp 27a will be lit in the second and subsequent AF operations.

In any case, at the end of the operation of <AFSIN2>, <5
After the routine DISCNT> is called and executed, <CALDIST> is called. <SD I
In the routine 5CNT>, the number of driving pulses from the infinite distance (oe3) position of the distance ring is set in the absolute distance counter. In the <CALD I ST> routine, from the number of pulses set in the above-mentioned absolute distance counter and the absolute distance coefficients a and b in the lens data circuit 18,
The absolute distance to the object is calculated, and the obtained absolute distance and the contents of the absolute distance counter are stored in the main CPU 1.
Sent to 4. The calculation of the absolute distance in <CALD I ST> will be described in detail later. <CALD IS
After T> is executed, AFSIN> as shown in FIG.
Returns to the position after the operation of <AFSIN2> in the flow of <AFSIN2>.

Next, in the flow shown in FIG. 4, <AFSEQ
> mode is selected, the <AF mode shown in Fig. 7 is selected.
SEQ> routine is called. This <AFSEQ
> Then, when the first step of the release button is activated,
After this, the first AF operation until the EOFAF signal becomes active is exactly the same as in the case of <AFSIN>. In other words, <AFSIN> is also <AF
SEQ> also performs the operation <AFS IN2>, and when focusing is not possible, the lens is actively driven abnormally and the user is notified.

By the way, in <AFSIN2>, as mentioned above, in low light and low contrast, the S lamp 27a is used to assist the δ-1 distance for AF operation, but in <AFSEQ> mode, If the S lamp 27a is used in the same way when AF operation is continued, the S lamp 27a will continue to emit light during the COD integral operation in <AF>, resulting in an increase in current consumption and an increase in S lamp 27a. Efficiency will decrease due to heat generated by the lamp 27a. Furthermore, if the lens is continuously driven abnormally when focusing is not possible, it will give the user a sense of anxiety.

Therefore, in <AFSEQ>, after one AF operation is executed and the EOFAF signal is set, the AFENA signal is determined, and if the same signal is active, the operation of the first stage of the release button is continued. <AFS>
The routine EQ2> is called. If the AFENA signal is inactive, it is assumed that the first stage of the release button has been turned off, and the second stage of the release button has been turned on, and the process returns. In <AFSEQ2>, as will be described later, CCD integration of the focus sensor 20, AF calculation, lens drive, etc. are performed, but the S lamp 27a is used to actively display the inability to focus due to abnormal lens drive and to measure the distance. is not lit either. And this <AF
As a result of the operation SEQ2>, the AP status flag is determined, and if the flag is 0, an in-focus display is performed, and if it is not 0, an in-focus display is performed. After the focus is displayed, an EOFAF signal is generated, and the exposure sequence can be started by operating the second stage opening of the release button. After this EOFAF signal is emitted, or after an indication that the focus is not possible is displayed, the AFENA signal test will begin again, so as long as the first stage of the release button is kept on, <AFSEQ2> AF centered on
! IJI works are performed continuously. And AFENA
When the signal becomes inactive, the process returns to the initial operation of the power-on reset flow shown in FIG.

Note that the EOFAF signal is cleared at I10 initialization (see FIG. 4) after CCD integration in the next AP operation or after return.

In the flowchart of the <AFSEQ> mode, the program operation of the <AFSEQ2> subroutine is performed as shown in FIG.

First, after the integration time is set in the ITIME register, the AP status flag is cleared and the S ramp flag is cleared. After this, the Lens Read subroutine is called and this is executed.

At this point, the lens data in the lens data circuit 18 is read out. Then, in the routine <AP>, after distance measurement is performed, the AF display circuit 24 is once turned off, and neither the in-focus display LED 24a nor the out-of-focus display LED 24b is lit. In other words, the AF display is not performed while the lens is being driven. Then -E
After clearing the OF A F signal, the LC flag is determined, and if the contrast is low, the process returns, and if the contrast is low, the ``delete pulse'' subroutine is called.

Note that even in low light, distance measurement calculations are possible if there is contrast, so the determination of the LL flag is intentionally omitted. As mentioned above, in Ku Pulse,
A lens data circuit 1 is used to convert the AF calculation output value obtained by the <AF> operation into a distance movement amount for each interchangeable lens.
The magnification coefficient is read from 8, and the number of drive pulses (number of addresses) is calculated from this and the AF calculation output value. Then, the AF calculation output value (ERROR) is compared with the AP accuracy threshold ETh, which is lens data, and if the ERROR is larger than the threshold ETh, <MDRIVAF> is called and the lens is driven to the in-focus position. will be carried out. After this, <5 DI
SCNT> is called and the absolute distance counter is set to the number of driving pulses based on the position renormalized to infinity (oo) of the lens, and then <CALD I ST
>, the number of driving pulses set in the absolute distance counter and the absolute distance coefficients a, b, which are lens data.
Once the absolute distance from and to the subject is calculated, the process returns. The calculated value of this absolute distance and the number of driving pulses set in the absolute distance counter are the main CP.
Sent to U14.

Furthermore, if the ERROR is smaller than the threshold ETh to the extent that it falls within the focus error range, the AF status flag is cleared and the process returns.

Next, in the flow shown in FIG. 4, if the mode <PF> is selected, the routine <PF> shown in FIG. 9 is called. In the routine of this PF〉,
First, the AFENA signal is determined, and if the signal is not active, it returns; if it is active, that is, if the first stage of the release button is on, the EO
By setting the FAF signal, the second stage operation of the release button is enabled. In other words, it is possible to shift to the exposure sequence at any time during PF. After that, the lens write/read> is called, and lens data such as the power focus duty coefficient in the lens data circuit 18 is read out, and then the state change flag is cleared. The power focus duty coefficient includes speed control coefficients for HI (high) speed and LO (low) speed for each lens. Status change flags include the DIFSP (speed change) flag, which is set when the speed changes, and the DIFMO flag, which is set when the mode changes.
There is a D (mode change) flag.

After this, Kumode Read> is called, and here,
The instructions for the lens rotation direction and lens drive speed are read, and the lens rotation direction UP (up) and DN (
(down) is set or cleared, and the SP (speed) flag is set or cleared. That is, the on/off state of the operation switch sw-5w4 regarding the lens drive mode shown in Table 1 is read. In this <PF> mode, the operation switch SW
3 is on, and the PFUP operation switch SW
When 1 is turned on, the lens rotation direction is the UP (lens extension) direction, and the PFDN operation switch S,
When W2 is turned on, the lens rotation direction is the DN (lens retraction) direction. Then, the SP flag is determined, and when the operation switch SW4 is turned on, this SP flag is set, and in this case, the pulse current that drives the lens drive motor 31 (see Figure 3) is The on/off duty ratio is set high,
The lens is extended or retracted at high speed. This is because the SP flag is cleared when the operation switch SW4 is off.

In this case, the duty ratio of the motor drive pulse current is set low and the lens is moved at a low speed.

After this, the %<PDRV> subroutine is called.

In <PDRV>, the motor 31 is turned on and off based on the duty ratio set above, and the lens is driven for one pulse. Next, the lens moves to infinity (o
o) Or, after determining whether or not the motor has hit the nearest limit position and stopped, if it has hit the limit position and stopped, apply a brake of about 100m5 to the motor and <SD I 5CNT > and set the absolute distance counter. Then, in this state, it waits while going around the mode change loop to see if there is any change in the mode signal.

In this mode change, changes in the state of the PFUP operation switch SW and PFDN operation switch SW2 (mode change) and the state change of the speed operation switch SW4 (speed change) are checked, and the mode change If there is a speed change, set the DIFMOD flag, and if there is a speed change, set the DIFMOD flag.
The P flag is set. And among these, DI
If the FMOD flag is set, this is determined and the process returns to [F].

On the other hand, in the case of normal power focus operation where the lens does not reach the limit position, the above motor is turned on and off in the <5PCTL> routine so that the lens drive speed becomes the determined coarse and fine movement speed. Fine-tune the off duty ratio. That is, speed adjustment by turning on and off the lens drive motor is performed by <PDRV> and <5PCTL>. After this, A F E N
Check the A signal, and if the signal is active, that is, the first operation of the release button is not turned on, and the mode change is called, and at this time, the speed has not been changed. If the DIFSP flag is set, it returns to [F] as it is, and if there is no speed change and the DIFMOD flag is set and a mode change is made, the brake is called and the motor is stopped. 5DISCNT> to set the absolute distance counter and return to [F]. If there is no speed change or mode change, it returns to <PDRV>, and as long as the first stage of the release button remains on, <PDRV>
The PF operation based on <5PCTL> is continued.

When the operation of the first stage opening of the release button is turned off, the AFEN
The A signal becomes inactive, that is, the end of the PF operation is instructed by the main CPU 14, the brake> is called to stop the motor, and the absolute distance counter is set at <5DISCNT>. Then, calculations are performed in <CALDI ST> from the contents of the set absolute distance counter, that is, the number of addresses moved from the infinite (oo) position and the absolute distance coefficients a and b in the lens data circuit 18. An absolute distance is calculated, and this calculated absolute distance information is sent to the main CPU 14.

After this <CALD I ST>, the process returns to the initial state of power-on reset.

Next, the above 6. The calculation formula for the absolute distance in <CALDI ST> in the flowchart shown in FIG.

The absolute distance counter is set with the number of pulses (address signal) that corresponds to the amount of movement of the lens from the infinity (oo) position, so if the amount of lens movement can be approximated as a linear function, the absolute distance can be obtained by calculation. becomes possible.

Here, when we investigated the relationship between the lens movement amount and the absolute distance for each interchangeable lens barrel, we found that lenses A and B appear on the logarithmic graph as shown in FIG.

It was found that C and D, except for the macro area of lens D, are represented by a -th straight line graph. That is, if the amount of lens movement is y and the distance is X, then fIogy-1α10gt
It is expressed by the formula: oX+β・<1)O. However, the amount of lens movement is based on the infinite position, and in the above equation (1), α, β>0. Taking the logarithm from both sides of the above equation (1) yields X″′, which includes the α-order function of X.Here,
If the amount of extension of the distance ring relative to the rotation angle is designed using a cam so that α■1, then the absolute distance can be calculated without error. However, in practice, it is difficult to design a cam that satisfies this formula, so when designing a lens, a simpler approximation formula is used: y = −+ c (3) Let us choose a hyperbola called -a. Here, in the above equation (3), y is the amount of lens extension from the infinity (oo) position, that is, the number of address signals saved in the absolute distance counter, and X is the absolute distance. −■
In this case, since y-0 (when the distance is infinite, the lens extension is 0), it can be approximated by the following equation (4) using C-O in the above equation (3).

y= (4)-a When this equation (4) is expressed logarithmically, it becomes Rogy=Nogb-Rog(x-a)-(5). This equation (5) is illustrated in FIG. 11. In other words, this equation (5) is! I ogy-D o
gt)-ffogx and x-a, and the curve portion changes as the value of a changes. In other words, the relationship between the absolute distance and the lens movement amount for each interchangeable lens can be approximated using the straight line portion and curved portion of equation (5) above. Note that in the above equation (5), a, b>0, and it is clear that the value of a is not larger than the closest distance of the lens. These a and b are absolute distance coefficients stored in the lens data circuit 18.

In order to actually find the absolute distance for the amount of lens movement from equation 5) above, it is necessary to determine the absolute distance coefficients a and b. Therefore, this absolute distance coefficient a.

To find b, please use Section 10 (1) for each lens barrel.
) to obtain the above equation (2). Then, based on this equation (2), next the above approximate equation (
Find the values of a and b in 4). That is, first of all, if you want to make the error 0 for example 3m as the distance used as the calculation standard, substitute x-3m into the above equations (2) and (4), and from both equations, Find the combination of a and b.

Then, from among these several combinations of a and b,
Furthermore, the error within the required distance range is minimized (a
, b). For example, from x-1m to x-
If a distance of up to 10 m is required, find a and b that will minimize the error between the two equations above.

Once a and b are determined in this way, the curve expressed by equation (5) is determined, and the absolute distance X can be determined from the value of y, that is, the number of addresses saved in the absolute distance counter. .

Characteristic lines based on actual a11 values for lenses B and D and the above (
The characteristic line obtained by approximating equation 5) is shown in FIG. 12. In addition, the characteristic line of one lens is divided into several regions, and the small parts with different a and b are divided into 8%, w-frz; r-1, fake; −
From the position to, predetermined values of a and b are selected, and the absolute distance can be calculated from the selected values of a and b and the address value saved in the absolute distance counter. for example,
In Fig. 12, the macro area of lens D is 1 of a and b.
Although it has been found fairly accurately from an approximation formula using a combination of two, it may also be found using a split approximation.

The absolute distance coefficients a and b are stored as lens data for each m barrel of interchangeable lenses, or each interchangeable lens is identified on the camera side and stored in the ROM in the AF CPU 22.
Predetermined absolute distance coefficients a and b are extracted from within. Note that the absolute distance coefficients a and b can be set to a-0 if some error is allowed, and it is also possible to determine the absolute distance using only b.

In this way, correct distance information from the camera to the subject can be obtained during AF and PF.

Furthermore, if it is necessary to take into consideration play in the drive system, backlash, etc., the absolute distance coefficients a and b may be determined in consideration of this. In this case, a considerable effect on backlash can be expected.

Next, an example for calculating the absolute distance with higher accuracy will be described.

Possible errors when calculating the absolute distance are:
The distance-pulse (address) quadratic relationship is expressed as V-b/
There may be an error when replacing with (x-a). Since this is a theoretical difference of 2%, the absolute distance coefficient a,
b divided into zones (multiple absolute distance coefficients a,
b).

However, in actual implementations, erroneous pulses may be generated due to play in the drive system (for example, backlash in drive system gears) or vibrations that occur when the lens hits the infinity position or the close position. etc. are possible. Therefore, some embodiments will be described in which the error between the drive system and the control system is minimized.

FIG. 13 shows the slit 32 as shown in FIG.
An embodiment is shown in which a lens movement amount detecting section 34 uses one photointerrupter 33 consisting of a light emitting section 33a and a light receiving section 33b with a passage in between. An LED drive circuit 41 that drives a light emitting section 33a consisting of an LED and a light receiving section 33
A waveform shaping circuit 42 for shaping the waveform of the output of the output signal b is provided in the bipolar ■ circuit 15 (see FIG. 3). A counter driving pulse discrimination circuit 43 shown enclosed by a two-dot chain line is also constructed within the bipolar ■circuit 15.

The counter drive pulse discrimination circuit 43 is provided with a motor direction discrimination circuit 44 for detecting from the voltage across the motor 31 whether the lens drive motor 31 is in a normal forward rotation state or a reverse rotation state. The motor direction determining circuit 44 includes four comparators 47 to 50, four Schmitt trigger inverters 51 to 54, and two four-man NAND gates 55 and 56. That is, to describe the configuration of this motor direction determination port 44, the non-inverting input terminal of the first comparator 47 and the inverting input terminal of the second comparator 48 are connected to one terminal of the motor 31, and the third
The non-inverting input terminal of the comparator 49 and the inverting input terminal of the fourth comparator 50 are connected to the other terminal of the motor 31. Also, 1st. third comparator 47,
49 is connected to a reference voltage setter 45 which provides a reference voltage vrefl, and the second. The non-inverting input terminal of the fourth comparator 48,50 is connected to a reference voltage setter 46 which provides a reference voltage "ref2.

Here, the reference voltage given to each of the comparators 47 to 5o is, for example, vref'lΦ2/3Vcc.

It is set to 1/3 Vcc in vref'2. Now, when the motor 31 rotates in the forward direction, the voltage at the one terminal of the motor 31 becomes VCC, so at this time, the outputs of the comparators 47 to 50 are respectively °H''.

1L"IIL" becomes "H", so the output of one Nantes gate 55 becomes "L" and the output of the other Nantes gate 56 becomes "H". Further, when the motor 31 is in reverse rotation, the voltage at the other terminal of the motor 31 is V
Since it becomes CC, in this case, comparators 47 to 50
Each output is “L”, “H”, “H”, “
The output of one Nant gate 55 becomes "H",
The output of the other Nant gate 56 becomes "Lo".

The pulse from the lens movement amount detecting section 34 due to the rotation of the motor 31 is waveform-shaped by the waveform shaping circuit 42, and then, at the falling edge, a well-known differential circuit consisting of inverters 57, 58, a resistor 59, a capacitor 60, and a Nandt gate 61 is applied. The address pulse is differentiated by the pulse generating circuit 62, and the differentiated address pulse is inputted through the inverter 63 to one input terminal of the low active OR gates 64 and 65. The absolute distance counter 66 counts up by the pulse input to the down address input terminal when the up address input terminal is "H", and counts up at the up address input terminal when the down address input terminal is "H". This is a type of counter that counts down by manually input pulses.

When the output of one of the Nant's gates 55 of the motor direction determining circuit 44 is "L", regardless of the input level of one of the OR gates 64, the AF CPU 22 (see FIG. The input terminal of the up address of the absolute distance counter 66 provided in (see) becomes "H", and the absolute distance counter 66 comes to function as an up counter. At this time, "H" of the other Nant gate 56 of the motor direction discrimination circuit 44 is detected.
Since the output of o is input to the other input terminal of the OR gate 65, the absolute distance counter 66 is input from this OR gate 65.
The address pulse is inputted to the down address input terminal of , and the absolute distance counter 66 performs a count-up operation.

Furthermore, when the output of the other Nantes gate 56 of the motor direction determining circuit 44 is "L", the absolute distance counter 66 is counted down through this OR gate 65 regardless of the human power level of one of the OR gates 65. The address input terminal becomes “Ho” and the absolute distance counter 6
6 comes to function as a down counter. At this time, the "H" output of one of the Nant gates 55 of the motor direction discrimination circuit 44 is input to the other input terminal of the OR gate 64, so the up address of the absolute distance counter 66 is input from this OR gate 64. The above address pulse is input to the terminal, and this absolute distance counter 66
A countdown operation is performed.

Here, when the motor 31 is braked or stopped, if both ends of the motor are grounded by the control system and the potential difference between both ends becomes 0, at this time, both outputs of the Nant gates 55 and 56 become "H". Therefore, the absolute distance counter 66
becomes inactive.

That is, in the embodiment shown in FIG.
If the drive system mechanism operates due to forced external force when the lens is stopped and a pulse is generated for the photo ink club 33, or even if the motor 31 reaches the end position of the lens and is braked, the lens When a pulse is generated due to hunting at the end, the absolute distance counter 66 does not perform a pulse counting operation.
This has the advantage of minimizing absolute distance errors.

Note that the motor direction determining circuit 44 uses four comparators 47 to 50, and for example, two comparators are used to convert the voltage vce across the motor 31 to one reference voltage V (-1/2ar It may also be compared with Vce). The reason why four comparators 47 to 50 are used in the embodiment described in - is to prevent the absolute distance counter 66 from malfunctioning even if the driving voltage of the motor 31 fluctuates due to noise. The potential of the high potential side terminal is 2/3Vc
Within the range of c-Vcc, and the potential of the low potential side terminal is 1/
Even if it fluctuates within the range of 3Vcc to ground (0),
The motor direction determination circuit 44 operates normally and determines the rotational direction of the motor 31. The terminal potential of the motor 31 is intermediate 1.
When it is in the range of /3Vcc to 2/3Vcc, there is a dead zone for determining the motor direction, and the absolute distance counter 66 does not operate.

Further, in the embodiment shown in FIG. 14, the LED drive circuit 71
Between the waveform shaping circuit 72 and the first photo-interrupter 74, there is a first photo-interrupter 74 consisting of a light-emitting part 74a and a light-receiving part 74b facing each other across the path of the slit 73, and also a light-emitting part 75.
a and a light receiving section 75b.
5 constitutes a lens movement amount detection section 76.

As shown in FIG. 15, the two photo ink club toughs 4° 75 of the lens movement amount detection unit 76 are connected to a slit 73 of a rotating member 77 in a lens barrel rotated by a motor.
When detecting the slit 73, the arrangement is such that the detected waveform of the slit 73 has a phase difference of 90°.

That is, the waveform-shaped output of the first photo-interrupter 75 is used as a physiognomic output.
The waveform shaped output is output as the B phase, but when the motor rotates normally, there is a phase difference of 90 @ between the A phase and B phase output waveforms as shown in FIG.

A counter driving pulse discrimination circuit 78 is connected to the waveform shaping circuit 72, and the absolute distance counter 92 counts via this pulse discrimination circuit 78. This pulse discrimination circuit 78 includes a capacitor 80.84 for delaying the A-phase output of the waveform shaping circuit 72, a resistor 81.15, a Schmitt trigger inverter 79,
82.86, a Nant gate 83.87 connected to the output terminal of this delay circuit and the B-phase output terminal of the waveform shaping circuit 72, and this Nant gate 83.8.
A Nant gate 88.8 connected between the output terminal of 7 and the up/down switching input terminal of the absolute distance counter 92.
9 R-S flip-flops (hereinafter referred to as R5-FF
) 90, and a Nant gate 91 connected between the output terminal of the Nant gate 83, 87 and the address input terminal of the absolute distance counter 92.

Next, the operation of the counter drive pulse discrimination circuit 78 will be described using time charts of signal waveforms of each part shown in FIGS. In this case, as shown in FIG. 17, the A-phase output S of the waveform shaping circuit 72 has a waveform that is 90° ahead of the B-phase output S6. At this time, A
The phase output S1 is inverted by the Schmitt trigger inverter 79, and passes through a time constant circuit consisting of a capacitor 80 and a resistor 81, resulting in a waveform S2. In addition, A phase output S
1, on the other hand, passes through a time constant circuit consisting of a capacitor 84 and a resistor 85 without being inverted, and becomes a waveform S 2 . Waveforms S2 and S3 are converted into waveform S4 by passing through Schmitt trigger inverters 82 and 86, respectively.
．． It becomes S5.

When this waveform S and the B-phase output S6 are input to the Nantes gate 83, the output waveform of the Nantes gate 83 becomes S, and the waveform S5 and the B-phase output S6 are input to the Nantes gate 83.
7, the output waveform of the Nant gate 87 is S
It becomes 8. Then, this waveform s7. s8 is R3-FF9
0, the output of R5-FF90 becomes “H”.
The waveform S7 and S8 are input manually to the Nandt gate 91, so that the waveform S7 and S8 of the same Nandt gate 9
The output becomes waveform S1o. Therefore, in this case, the absolute distance counter 92 performs a count-up operation at the falling edge of the waveform S1o.

Further, when the motor 31 is reversed, that is, when the lens moves toward the closest direction, the above-mentioned A
The phase output S 2 has a waveform that is delayed by a phase of 90 @ than the B-phase output S 6 . Therefore, in this case, the signal waveform of each part in the counter driving pulse discrimination circuit 78 becomes a waveform as shown in FIG. 18, and the absolute distance counter 92 is given a "Lo" waveform S9 to the up/down switching input terminal. Then, a countdown operation is performed at the falling edge of the waveform S18 input to the address input terminal.

In this way, in the embodiment shown in FIG. 14, the direction of the motor 31 is determined by shifting the phase between the A-phase output and the B-phase output from the lens movement amount detection section 76 of the two photointerrupters 74 and 75. At the same time, when the motor rotates forward, the falling edge of the A phase output generates an up pulse, and the rising edge generates a down pulse. Even if the lens hits an end at infinity or a close end and generates a return pulse due to hunting, this return pulse can be accurately counted.

In the embodiment shown in FIG. 14 above, the rising edge and falling edge of the physiognomic output S1 are used.
Next, in the embodiment shown in FIG. 19, the rising and falling edges of the A phase and the rising and falling edges of the B phase are used to generate up/down pulses four times as much as the conventional one address movement amount. A counter operation pulse discrimination circuit 94 is used.

This counter driving pulse discriminator circuit 94 is a lens movement amount detecting unit consisting of two photo ink club toughs 4.75 (see FIG. 15) whose phases are shifted by 90 degrees, as in the embodiment shown in FIG. 14 above. A D-type flip-flop (hereinafter referred to as D-FF) 96.97 is connected to the waveform shaping circuit 72 of 76 and is related to the physiognomic output of the waveform shaping circuit 72.
and D-FF98, 99 regarding the B-phase output, and these D-FFs.
- A clock pulse generator 10G for sending clock pulses to the FFs 96 to 99, and each output A (or '2v), A2 (or 'X2), and B of the D-FFs 96 to 99.
1 (or T1), B2 (or T2) are input 8
4-person NAND gates 101 to 108 and two low-active 4-person KOA gates 109.1 connected between the output terminals of these NAND gates and the up address input terminal and down address input terminal of the absolute distance counter 95.
10. Nantes Gate 101 above
108 and ORG) 109 and 110 form a 4-fold pulse multiplication circuit.

In the embodiment shown in FIG. "H" generated by the rising and falling edges of the phase and the rising and falling edges of the B phase.
“A pulse is input to the up address input terminal of the absolute distance counter 95 and the other four Nant gates 102.1
04°106.108 and one OR gate 110, the “L” level is input to the down address input terminal of the absolute distance counter 95. Therefore, at this time, the absolute distance counter 95 performs a count-up operation with four times the resolution as compared to the embodiment shown in FIG.

In addition, when the motor 31 is reversed (when the lens rotates toward the closest direction), the Nant gates 102, 104, 106,
108 and the OR gate 110 to the down address input terminal of the absolute distance counter 95, the "H° pulse generated by each rising and falling edge of the A phase and B phase is input, and the other Nant gates 101. 103° 105.1
07 and the OR gate 109, the "L2 level" is input to the up address input terminal of the absolute distance counter 95. Therefore, in this case, the absolute distance counter 95 also performs a countdown operation with four times the resolution. In the embodiment shown in the figure, since pulse counting is performed with high resolution, it is possible not only to compensate for hunting when the lens hits the end position at infinity or at close range, but also to compensate for the backlash of the drive system gear. Even for movements caused by backlash such as rush, the counting error can be sufficiently compensated by counting the pulses corresponding to this amount.Furthermore, as in the above embodiment, only the rising edge or falling edge of the A phase can be counted. As shown in FIG. 20, in a device that performs counting, if the rotation direction of the motor is different, the count value will have an error of the maximum epulse count in the same movement section, but in this embodiment, Since such errors can be reduced to 1/4 or less, extremely accurate absolute distance counting can be performed.

Although the embodiments described above are applied to an interchangeable lens camera, the same effect can be obtained even when the embodiment is applied to a fixed lens camera.

Further, the present invention can also be configured by a system that does not require feedback to the drive control system, that is, an oven loop control system in which the drive amount corresponds one-to-one to the drive signal.

FIG. 21 is a block system diagram comprehensively summarizing the absolute distance calculation system of the distance information output device of the present invention. The purpose of the present invention is to obtain the absolute distance X.

Absolute pressure R#x is absolute pressure,! The f calculation means 510 calculates x
It is obtained by calculating -(b/y)+a. a
, b is an absolute distance coefficient unique to the photographic lens used, and is inputted to the absolute distance calculation means 510 by the absolute distance introduction means 51.
1 is input. In the case of an interchangeable lens camera, these coefficients a and b are stored in the lens ROM of each lens or in an equivalent storage member, and the values are read out from the camera body to calculate the absolute distance. is efficient. In a fixed lens camera, the above coefficient a is naturally contained within the camera body.

It is sufficient to have b. In the case of an interchangeable lens camera, there are multiple coefficients a and b inside the camera body.
Depending on the recognition code of the lens used, etc., the predetermined coefficient a,
A system that selects b is also possible, but this is not efficient. If we consider coefficients a and b as integers, coefficient a becomes an integer greater than or equal to 0 in order to suppress the absolute distance error,
If backlash of the drive system is taken into account, it may take a negative value.

The coefficient is a positive integer that does not include 0.

Regarding the calculation of the number of pulses from the reference position, that is, the lens movement my, the optimum reference position is the infinite position or the closest position, as described in the above embodiment. At the reference position, y in the counting means 504 is reset by the reference signal generating means 512 accompanying the lens reset operation. Thereafter, the relative distance is counted by the counting means 504.

In the embodiment shown in FIG. 3, the feedback loop for driving the lens is realized using the photo ink clubber 33, but the lens movement amount detecting means 501 may be implemented using other elements such as a photo reflector or a hole. An element or a mechanical switch can also be used instead. In this case, feedback loop control is used for the lens drive system, and the address signal generating means 50 controls the lens drive after movement.
The absolute distance counter of the counting means 504 calculates the count value of the relative distance as y while monitoring the output of 3 and the like.

Here, when the lens is driven by oven loop control, as shown in FIG. 22, the lens drive motor 31A may be a stepping motor, an ultrasonic motor, etc.
Use a motor suitable for oven loop control. Then, this motor 31A is driven by a lens movement control signal based on the amount of deviation to the in-focus point, and the lens movement control signal itself is manually inputted from the lens movement control signal detection means 502 to the address signal generation means 503. The movement my can be determined by manually inputting information to the counting means 504 to count the relative distance. In this case, as is clear from a comparison between FIG. 3 and FIG. 22, the oven loop controllable lens drive motor 31A
is used, the address signal generating means 5
The drive amount monitor section 34 (see FIG. 3) consisting of the photo ink printer 33 in 03 is omitted. Therefore, the address signal from the bipolar circuit 15 is sent to the AF CPU 2.
Since there is no need for manual input to 2, the address signal line can also be omitted. That is, in this case, the address signal and direction signal from the address signal generating means 503 can be processed within the AF CPU 22.

Further, in the case where the address signal generating means 503 has a drive amount monitor section, that is, when the lens drive needs to be performed by feedback loop control, and in the case of 1-phase pulse control (see FIG. 13), A drive signal (for example, an infinity direction drive signal and a pulse input signal in a brake section or a motor power supply stop section that follows it are determined as an infinity drive signal, and a near direction drive signal and a pulse input signal in a brake section or motor power supply stop section that follows it). It is necessary to devise a way to determine the direction of the input signal (the input signal is determined as the closest drive signal).

When performing control using pulses of two or more phases (No. 14)
．． (see Fig. 19), a direction signal can be obtained by the pulse discrimination means and can be utilized.

Furthermore, it becomes possible to realize a resolution-oriented L means as shown in FIG. When a manual means of pulse control of two or more phases is used, the structure of the absolute distance counter is as shown in FIG.
It is possible to have a configuration as shown enclosed in . for example,
As shown in FIG. 14, one absolute distance counter 50
5 (92) may be used to switch between count-up and count-down using a direction signal.
Instead of using such an absolute distance counter, as shown in FIG. 23, an address counter 508 (120) and an absolute distance counter 509 (121) may be used. That is, in the embodiment shown in FIG. 23, when a drive signal is generated, the address counter 120 is reset and the address counter 120 starts counting address information.

Immediately before the drive mode changes, the counter value of the address counter 120 is added or subtracted from the counter content of the absolute distance counter 121 using the drive direction signal S9 (for example, addition in the closest direction and subtraction in the infinity direction). It is composed of

[Effects of the Invention] As described above, according to the present invention, a highly accurate absolute distance can be obtained by calculating the count output according to the relative distance from the photographic lens using a simple calculation formula. It can be made suitable for system cameras.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the basic configuration of the distance information output device of the present invention, FIG. 2 is a block diagram of an electric circuit mainly for power supply of a camera system to which the present invention is applied, and FIG. is a block system diagram showing the transmission and reception of signals centered on the AF block in Figure 2 above, and Figures 4 to 9 are one implementation of a program centered around the AF CPU shown in Figure 3 above. A flowchart showing an example, FIG. 10 is a characteristic diagram showing the relationship between the absolute distance and the amount of lens movement in each interchangeable lens barrel, and FIG. A diagram for explaining the approximate characteristic line of absolute distance. FIG. 12 is a characteristic diagram of a part of the lens barrel shown in FIG. 13 is an electric circuit diagram showing one embodiment of a pulse discrimination circuit for driving a counter for calculating absolute distance with higher accuracy. FIG. 14 is an electric circuit diagram showing another embodiment of a pulse discrimination circuit for driving a counter. An electric circuit diagram showing an example; FIG. 15 is a schematic diagram showing the configuration of the lens movement ffi detection section in FIG. 14; FIG. Figures 17 and 18 are time charts of phase output waveforms, and time charts of signal waveforms for each part of the circuit shown in Figure 14 when the motor rotates forward and reverse. An electric circuit diagram showing still another embodiment of the pulse discrimination circuit, FIG. 20 is a time chart for explaining the count error that occurs when the motor rotates forward and reverse, and FIG. 21 shows the distance information of the present invention. FIG. 22 is a block system diagram of the absolute distance calculation system of the output device, and FIG. 23 is a block system diagram corresponding to FIG. FIG. 15 is an electric circuit diagram corresponding to FIG. 14 showing the configuration of the embodiment.

Claims (1)

[Scope of Claims] Counting means for counting the relative distance according to the movement of the photographing lens; reset means for resetting the count value of the counting means when the photographing lens reaches a reference position; Distance information for a camera, comprising: a storage means for storing unique data of a photographing lens for converting a count value into an absolute distance; and a calculation means for calculating an absolute distance based on the unique data and the count value. Output device.