JPH02139510A - Automatic focus adjusting device - Google Patents

Abstract

PURPOSE:To stop a photographic lens motor without overrunning an expected position even in the case of fast driving by driving the photographic lens motor at its full speed when an expected driving quantity is larger than a specific value, and varying a duty ratio and driving the motor when the expected driving quantity is smaller than the specific value. CONSTITUTION:The rotational position of a distance ring 9 is determined by converting the on-off signals of a 1st zone switch 38 and a 2nd zone switch 39 into Gray codes. Further, the quantity of rotation of the distance ring 9 is counted detected by counting on-off pulses of an ADR switch 40 by a specific counter. Then, a CPU compares the expected driving quantity with the specific value to drive the driving motor at its full speed when the driving quantity is larger than the specific value, and vary the duty ratio and drive the motor when the quantity is smaller than the specific value. Therefore, the motor can be stopped without overrunning the expected position even when the fast driving is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic focus adjustment device, and more particularly to an automatic focus adjustment device in a camera, which has a lens drive motor that drives a photographic lens according to the output of a focus detection means.

In this kind of conventional automatic focusing device, the photographing lens is driven at a constant speed by a lens driving motor. For this reason, if the drive speed of the motor is set high in order to perform a high-speed focusing operation, the planned stop position is likely to be exceeded, and if the drive speed is set to a low speed to avoid this, the focusing operation may take longer. There was a problem.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an automatic focusing device capable of controlling the motor to accurately stop at a predetermined position even if the driving speed of the motor is increased, in order to eliminate the above-mentioned conventional problems.

Hereinafter, the present invention will be explained based on illustrated embodiments.

1 to 4 are a perspective view, a rear view, a side view, and a schematic cross-sectional view of a lens barrel having an automatic focus adjustment device showing one embodiment of the present invention.

1 to 4, a zoom ring 2 is rotatably provided on a fixed frame 1 of a lens barrel, and pins 4 and 5 engaged with cam grooves of a cam barrel 3 are moved by the rotation of the zoom ring 2. It moves in the direction along the optical axis O. The pin 4 is implanted in the front group lens frame 6 and the cylindrical body 7 screwed together with the helicoid, and the pin 5 is implanted in the rear group lens frame 8. Therefore, when the zoom ring 2 is rotated, the front group lens frame 6 and the rear group lens frame 8 move along the optical axis O according to the shape of the cam groove so that the focal length changes from wide angle to telephoto. Front group lens frame 6
A distance ring 9 is screwed together with a helicoid screw, so that when the distance ring 9 is rotated, the front group lens frame 6 rotates and moves along the optical axis 0. At this time, fixed frame 1
The distance is displayed in an index window 18 provided in the outer cylinder 1a according to the rotation of the distance ring 9. An aperture ring 10 is provided near the rear end of the fixed frame l, and rotation of the aperture ring 10 causes an aperture stage setting lever 11 (see Figure 2) to rotate, thereby determining the number of aperture stages. . The aperture blades 12 provided in the rear group lens frame 8 are stopped down by an aperture lever 13, which is controlled by the camera.

A case 14 is provided integrally with the outer tube 1a of the fixed frame 1 at the lower part of the main body of the lens barrel. A mode selector switch 15 is provided on one outer surface of the case 14, and switching between P and F is possible by switching the switch 15.
, (power focus), OFF (power off),
SIN, AF (single autofocus), SEQ
, AF (Sea Fence Auto Focus) and BAT
.

Each mode of C (battery check) can be selected. An operation plate 17 having two upper and lower operation buttons 16A and 16B is provided between the case 14 and the outer tube 1a of the fixed frame 1 on the same outer surface, that is, at a middle height position that is easy to operate with this lens barrel. It is being Operation button 16A
, 16B, the mode changeover switch 15 is P,
When in position F, these buttons 16A, 16B
When pressed, it becomes an operation button for P, F, UP, which rotates the distance ring 9 toward the short distance side by a motor, and for P, F, and DN, which rotates it toward the long distance side, and the mode changeover switch 15 is set to SIN. , AF, SEQ, and AF, these buttons 16A.

16B is an operation button for AF 5TAT (focus start) which rotates the distance ring 9 to the focusing position, regardless of which button is pressed, and the operation buttons are shared between the PF mode and the AF mode. It has a simple operability and appearance.

An in-focus trigger socket 19 is provided on the opposite side surface of the case 14. The trigger socket 19 is connected to the photographing lens 2 of the front group lens frame 6 by rotating the distance ring 9.
This socket 19 is for taking out this goldfish signal to the outside when 0 reaches the in-focus position.A motor drive device or winder is connected to the same socket 19 by a cord, and the motor drive device, winder, etc. can be triggered by the goldfish signal. It looks like this. Further, a sound switch 21 is provided on the back of the case 14, and when the switch 21 is turned upward, the switch is turned on and various warnings are emitted by sound, and the warning sound is muted. If you wish to do so, switch to the lower silent side and turn off the switch. A signal pin 22 is provided on the mounting surface of the fixed frame 1 of the lens barrel to enable the camera to recognize the camera when it is attached to a dedicated camera and to transmit a release signal.

As shown in FIG. 4, a flexible substrate 26 having a motor 23, IC chips 24, 25, etc. is housed inside the case 14.

The motor 23 is meshed and connected to the outer periphery of the distance ring 9 through a gear train 27, and the rotation of the motor 23 rotates the distance ring 9, thereby driving the photographing lens 20. At a predetermined position above the rear part of the case 14, a focus sensor 28 made of a CcD is mounted on the flexible substrate 26. Light that passes through the photographing lens 2°, is reflected by the half mirror 3o of the prism 29, passes through the prism 29, and is further reflected by the reflection mirror 31 is guided to the light receiving surface of the focus sensor 28. The light receiving surface of this sensor 28 is located at a position conjugate with the film surface. Therefore, the rear aFJ distance is performed using TTL incident light.

Four brush-shaped contact pieces 32 to 35 are attached to the fixed rod 1 surrounded by the case 14, and the contact pieces are wired to the board 26. The contact pieces 32 to 35 are the fifth
As shown in FIG. 1, it comes into sliding contact with the rear outer periphery of the distance ring 9. A conductive pattern 37 is provided on the rear outer periphery of the distance ring 9.
is formed.

The conductive pattern 37 has two strips 37 as shown in the figure.
a, 37b, and a comb tooth portion 37c continuous to the band portion 37b. Contact pieces 32 to 35 are contact pieces for zone 1, zone 2, common, and ADR (address), respectively. Therefore, contact pieces 32 and 34, and 33 and 34 are contact pieces for zone 1, zone 2, common, and ADR (address), respectively. A second zone switch 38,39 is formed, and the contacts 35 and 34 form an ADH switch 40. Contact piece 32
34, when the distance ring 9 is at the rotational position corresponding to the intermediate distance zone, the contact pieces 32 to 35 each touch the strip portion 3 at a position Po of the conductive pattern 37, for example.
7a, insulating section 9a, and band-shaped section 37b.

It faces the comb tooth portion 37c. Since the contact pieces 34 and 35 always come into contact with the strip portion 37b and the comb tooth portion 37c when the distance ring 9 is rotated, the ADH switch 40 is turned on and off for each IADR when the distance ring 9 is rotated. The state of contact between the contact pieces 32 and 33 with the conductive pattern 37 differs depending on the rotational position of the distance ring 9, and when the distance ring 9 reaches the closest position, the contact pieces 32 and 3
3 is a position P on the conductive pattern 37 common to the contact piece 34.
Therefore, at the same position, the zone switch 38°3
9 are both on, and at the above position Po, the first zone switch 38 is on and the second zone switch 39 is off. Further, when the distance ring 9 is rotated to a position immediately before reaching the infinite position, the contact pieces 32 to 35 correspond to the position Pr, and the strip portion 37a is formed at the same position. do not have.

Therefore, both zone switches 38 and 39 are off at the same position. Further, when the distance ring 9 is rotated to the infinite position, the contact pieces 32 to 35 correspond to the position Poo,
Although the strip portion 37a is not present at the same position, the insulating portion 9
Since the conductive part 37d integrated with the strip part 37b is formed at the extended position of a, the first zone switch 3
8 is off, and the second zone switch 39 is on. As a result, the rotational position of the distance ring 9 can be gray-coded by the zone switch 38, 39, and the upper shift zone switch 38, 39 can be turned on by 0. If off is set to 1, the zone signal is (00) in the zone of the above-mentioned closest position Pn.
, in the zone at position Po (01).

In the zone of the far position Pr (11), the infinite position Po.

The rotational position state of the distance ring 9 can be determined by reading these signals. In this lens barrel, when the zone switch is in the zone of the above position Po, the rotation of the motor is maintained at a high speed state, and when the zone switch reaches the zone of the above position Pr from the same state, the motor is made to rotate at a low speed, and the rotation speed of the motor is set to a low speed, and the rotation speed of the motor is set to a low speed when the zone switch is in the zone of the above position Po.
The motor stops rotating when it reaches the zone. Further, the rotation of the motor also stops when the zone at the position Po reaches the zone at the position Pn. By slowing down the rotation of the motor in the zone of the far position Pr, the distance ring 9 smoothly stops in the infinite position P Cx3 zone,
It will stop just before colliding with the stopper. In addition,
Similarly to the above-mentioned far position P'', from the above-mentioned position Po to the close position P
Although the motor may be rotated at a low speed even before reaching the zone n, the frequency of use is particularly high at the infinite position Poo, and the effect is great.

Further, a brush-shaped contact piece 41 is provided on the outer periphery of the zoom ring 2 in a portion surrounded by the case 14.
As shown in an enlarged view in FIG. 6, a zoom information detector 42 is configured together with a conductive pattern 45 formed on a zoom substrate 44 that is integrated with the case 14. The conductive pattern 45 includes an integrated conductive part 45a that contacts the contact piece 41 and the zoom ring 2 regardless of the rotation angle, and a conductive part 45b that is divided into multiple parts in the moving direction so that the position can be determined according to the rotation angle. Each of the conductive parts 45b is composed of a resistive part 45c connected to each other by a resistor, and each of the conductive parts 45b is connected to the contact piece 45c.
The pattern is slanted so that either side can always come into contact with 1. This zoom information detector 42 is connected to the zoom ring 2
This is to ensure that the distance measurement is performed normally no matter what rotational position the zoom information detector 42 has.

The aperture ring 46 integrated with the aperture lever 13 has a shape shown in FIG.
As shown in A) and (B), when a substrate 48 having a conductive pattern 47 is integrally contained, and the aperture lever 13 is not narrowed down, as shown in FIG.
At least one of the fixed contact pieces 49 and 50 extending to the diaphragm lever 1 contacts the insulating portion of the board 48 to create a non-conducting state between the joint pieces 49 and 50.
3 is narrowed down even slightly, and the aperture ring 46 is adjusted to the position shown in Fig. 7 (
When rotated in the direction of the arrow as shown in B), the substrate 48
also moves together with the ring 46, so the contact piece 49.50
Both contact the conductive pattern 47 and become electrically conductive. That is, the contact pieces 49 and 50 constitute an aperture interlocking switch 51 for detecting the start of aperture reduction, and the switch 51
When this lens barrel is attached to the camera, it is possible to detect whether it is before or during shooting. The aperture interlocking switch 51 is used to prevent the photographic lens from being driven during release, and to prevent the necessary light from entering the focus sensor 28 when the aperture is closed, which can cause malfunctions. This is to do so.

In addition to the above-mentioned configuration, the lens barrel is configured to have various functions, which will be described in more detail with reference to the drawings from FIG. 8 onwards.

FIG. 8 is a circuit diagram of an electric circuit constructed inside the case 14 of the lens VT barrel. This electric circuit includes a power supply circuit 60, a CPU (central processing unit) 61, an oscillation circuit 62 externally attached to this CPU 61, and a CPU 61.
an A/D converter 63 connected to the A/D converter 63 via a pass line, the focus sensor 28 that sends a CCD output to the A/D converter 63, and an input terminal I2 of the A/D converter 63.
the zoom information detector 42 connected to the zoom information detector 42; the battery voltage detection circuit 64 connected to the input terminal 11 of the A/D converter 63; the motor drive circuit 65 connected to the output terminals 07 to 010 of the CPU 61; A switch circuit 66 connected to the input terminals 11 to I8 of the CPU 6
Warning display circuit 67 connected to output terminals 01 to 03 of 1
, a power holding circuit 68 connected to the output terminal 04 of the CPUGI, an in-focus trigger circuit 69 connected to the (I10) terminal of the CPU 61, a sound generation circuit 70 connected to the output terminal 05 of the CPU 61, and a power supply holding circuit 68 connected to the output terminal 04 of the CPU 61. The ADR switch circuit 71 is connected to the input terminal 11o of the ADR switch circuit 71.

The power supply circuit 60 includes a power switch 74, a battery 75, transistors 76 to 82, and a phototransistor 83.
, DC/DC converter 84, diodes 85, 86,
Capacitors 87-89, choke coil 90, resistor 92
-99 and switches 100-102. The terminal 103 is for guiding a release signal from the camera body, and corresponds to the signal pin 22 described above. terminal 1
04 is a terminal for supplying a power supply voltage of -5V to the CPU 61 and the circuit connected to this CPU 61; terminal 10;
5 is a terminal for supplying a power supply voltage of -3 to -4.5V to the motor drive circuit 65, battery voltage detection circuit 64, etc.

The operation of this power supply circuit 60 is as shown in the flowchart shown in FIG. The power switch 74 is linked to the mode changeover switch 15 shown in FIG. 1, and when the changeover switch 15 is changed to a mode position other than OFF, the power switch 74 is turned on. After this, transistor 78. When any of the switches 100 to 102 is turned on, the transistors 79 and 80 are turned on, the DC/DC converter 84 is activated, and a power supply voltage is generated at the terminals 104 and 105. The transistor 78 is turned on when a release signal is introduced from the camera to the terminal 103. The switch 100 is a switch that is turned on when the mode selector switch 15 is set to the BAT or C (battery check) mode position, and the switches 101 and 102 are the first switch.
These are switches that respectively operate in conjunction with the operation buttons 16A and 16B shown in the figure. Note that when the release signal from the camera is guided to the terminal 103, the transistor 76 is turned on, thereby turning on the transistor 78, but at this time, the transistors 81 and 82 are turned on,
A REL (release) signal is introduced to the input terminal I3 of the CPU 61.

When the power supply voltage is supplied to the CPU 61 from the power supply circuit 60, the CPU 61 is reset and then starts a program. At this time, in order to prevent the CPU 61 from malfunctioning due to noise when the power is turned on, the power holding circuit 68 is activated after a certain wait time. In the power supply holding circuit 68, when an "L" signal is issued from the output terminal 04 of the CPU 61 through the resistor 106, the transistor 107 is turned on, and the LED (light emitting diode) 109 of the photocoupler 108 emits light. LED
When 109 emits light, the phototransistor 83 of the power supply circuit 60 receives this light and turns on the phototransistor 83, which turns on the transistor 77. When transistor 77 is turned on, the initially turned on transistor 78 . Even when the switches 100 to 102 are turned off, the transistors 79 and 80 are kept on, and power continues to be supplied thereafter. Note that the power supply holding circuit 6
Reference numeral 116 in 8 is a resistance.

The oscillation circuit 62 includes a crystal oscillator 110° oscillation capacitors 111, 112 . It consists of a power-on reset capacitor 113. Further, the A/D converter 63 is connected between the CPU 61 and the I10 terminal by a pass line, and is operated by the system clock from the CPU 61. The A/D converter 63 supplies a signal corresponding to the focal length information from the zoom information detector 42 and a battery monitor voltage VBAT from the battery voltage detection circuit 64 to an input terminal 11.degree. I2 for A/D conversion. The battery voltage detection circuit 64 uses variable resistors 114 and 115 to set the voltage VBAT according to the battery 75. The A/D converter 63 A/D converts the output of the focus sensor 28, and sends a CCD drive clock and a CCD control signal to the focus sensor 28 to drive and control the sensor 28.

The motor drive circuit 65 is connected to the motor 23. transistor 1
17-124, diode 125, 128° resistance 127
138, and is driven and controlled by the output of the CPU 61. Describing the operation of this motor drive circuit 65, when the output terminals 07 and 09 of the CPU 61 go to the 'L' level, the transistors 117 and 124 are turned on, so the transistors 119 and 122 are turned on at this time, and the motor 23 is turned on. The distance ring 9 is rotated to the short distance side, and the output terminals 08, 0, . are set to "L".

When the level is reached, the transistors 118 and 123 are turned on, which turns on the transistors 120 and 121, and the motor 23 rotates in the opposite direction to the above, thereby rotating the distance ring 9 to the far side. Also, when the output terminals 08 and 09 both reach the 1V level while the motor 23 is rotating,
At this time, transistors 118 and 124 are turned on, transistors 120 and 122 are turned on, and the remoter 23 is braked. That is, at this time, a back electromotive force is applied between both terminals of the motor 23 by the transistor 120 and the diode 126, or the transistor 122 and the diode 125, and the motor 23 suddenly comes to a halt.

The switch circuit 66 is connected to the input terminal It of the CPU 61.
, I2, 14 to I8, respectively.
It consists of groups 1 to 147. Switches 141 and 142 are mode switches for determining each mode state other than OFF of the mode changeover switch 15 shown in FIG.
P and F by turning on and off switches 141 and 142
, , SIN, AF, SEQ, AF, BAT, C
The state of each mode is determined. Switches 143, 144
are switches that are respectively closed by operating buttons 16A and 16B shown in FIG. Further, the switches 145 and 146 are the first and second switches shown in FIG. 5, respectively. This is the second zone switch 38,39. Furthermore, the switch 147 is the aperture interlocking switch 5 shown in FIGS. 7(^) and (B) above.
It is 1.

The warning display circuit 67 includes transistors 151 to 153;
It consists of LEDs 154-156 and resistors 157-162. Each transistor 151-153 is connected to an output terminal o1. o2. When o3 reaches the "L" level, each of them turns on, and at this time, each of the LEDs 154 to 156 emits light and enters a display state. The first LED 154 displays a warning about subject movement, and when the subject is moving so fast that the focusing operation cannot follow the movement of the subject, this LED 154 emits light to warn the user. In addition, the second LED 155 is used to display a warning about the short distance limit, and when the photographic lens approaches the subject too close to the subject and distance adjustment becomes impossible, this LED 155
5 emits light. The third LED 156 is for displaying a low-contrast warning, and when the contrast of the subject is extremely reduced and it becomes difficult to adjust the distance M, this LED 156 emits light in the extreme contrast state. In addition, the first
．． When the second LEDs 154 and 155 are turned on at the same time, a low light warning is issued. That is, if the background is very dark and a sufficient amount of light does not enter the focus sensor 28, accurate focusing will not be possible. The second LEDs 154, 155 both illuminate to alert the user of this. In this way, the warning display circuit 67 displays four types of warnings using the three LEDs 154 to 156. These warning displays are internal displays that the user can see when looking through the camera's viewfinder.

The in-focus trigger circuit 69 includes a selector switch 164 and a transistor 165 connected to the terminal (Ilo) of the CPU 61. Resistors 166 to 168 and contact 19a of in-focus trigger socket 19 shown in FIG. 3 above,
19b. In-focus trigger socket 19
An in-focus trigger cord 170 is connected to the contacts 19a and 19b by insertion into the socket 19, so a motor trigger circuit 171 of the winder is connected via the trigger cord 170. Above selector switch 1
64 is a self-socket 19 on the top (when the trigger cord 170 is not inserted, it is switched to the contact 164a side, and when the trigger cord 170 is inserted, the changeover switch 164 is switched by the tip of the plug of the trigger cord 170. teeth,
The switch is switched to the contact 164b side, and the transistor 165 is connected to the terminal (Ilo). The switching state of this changeover switch 164 is detected next to C and PU 61. Therefore, when the winder is connected by the trigger code 170, the transistor 16
5 is turned on in the focused state, and at this time, when the LED 173 of the photocapsule 172 of the trigger code 170 emits light, the phototransistor 174 is turned on, and subsequently the transistors 175 and 176 are turned on, and the motor trigger circuit 171 of the winder is turned on. is activated, and the winder releases the shutter and winds the film. Note that the reference numeral 177 in the trigger code 170 is a resistor.

The sound generation circuit 70 includes a transistor 180. PCV (piezo ceramic vibrake) 181 and resistor 182,
It consists of 183. Transistor 180 is CPU6
When an "L" level signal is led from the output terminal 05 of the PCV 181, the PCV 181 is activated and generates a warning sound. This warning sound can also be prevented from sounding by using the sound switch 21 shown in FIG. 2 above. In this case, the sound switch 21 connected to the input terminal I9 of the CPU 61 is opened.

The ADR switch circuit 71 is the AD switch circuit 71 shown in FIG.
It consists of an R switch 40, a resistor of 185 to 187 degrees, an anti-chattering IL capacitor 188, and a waveform shaping comparator 189, and the output terminal of the comparator 189 is connected to the input terminal (2) of the CPU 61. The doujinshi terminal '10 is the ADR counter 1 configured in the CPU 61.
It has 90 input terminals. Therefore, when the distance ring 9 rotates, the ADR switch 40 is
When each DR is turned on and off, the ADR counter 190 counts the number of pulses (ADR) corresponding to the rotation angle of the distance ring 9, and the counter 190 detects the amount of rotation of the distance ring 9.

As described above, the main electric circuit inside the case 14 of the lens barrel is configured.

Next, a more detailed operation of the electric circuit of the lens barrel will be explained in accordance with a program installed in the CPU 61, with reference to the flowcharts shown in FIG. 10 and subsequent figures. First, when the mode selector switch 15 on the lens barrel is set to a mode other than OFF, the power switch 74 is turned on as described above, and at this time the CPU 61 is powered on as shown in FIG. The circuit goes into reset state,
As a result, the CPU 61 is initialized and all flags are cleared. After waiting to prevent malfunction until the power supply stabilizes, the power supply holding state is entered and the LED 109 of the power supply holding circuit 68 is turned on.

Thereafter, a system clock is supplied from the output terminal 06 of the CPU 61 to the input terminal I4 of the A/D converter 63. Thereafter, it is determined which mode has been selected by the mode changeover switch 15. By turning on and off the mode switches 141 and 142 of the switch circuit 66, the BAT and C modes are (00), the P and F modes are (01), and the SIN and AF modes are (10) and SE.
Q: AP mode is compatible with code (11), so BAT.

If in C mode, battery check BCHKl, P
, F, mode, power focus operation POWE
If the mode is R, SIN, or AF mode, the routine goes to AFSINl or SEQ for single AFL operation, and if it is AF mode, the routine goes to AFSEQ for sequence AF operation. The operation of each mode will be explained below.

(1) When in BAT, C (battery check) mode.

When in the BAT or C mode, the CPU 61 first performs the INBATT operation, as shown in FIG.

That is, the monitor voltage vB from the battery voltage detection circuit 64
The A/D converted result of AT is taken into the CPU 61. After this, the above voltage ■ and a certain constant voltage V
u , V L (V o > V L )BAT are compared, and if the voltage VBAT is higher than the voltage V11 that can be driven sufficiently, the sound generation circuit 70 emits a continuous sound, and if the voltage VBAT is lower than the voltage V11, If the voltage is higher than the minimum voltage VL for driving, an intermittent sound is generated. By listening to the sound generation state at this time, the user can know whether the voltage of the battery 75 is sufficient or whether it is time to replace the battery 75. The above monitor voltage v
When BAT is vBAT < vL, there is a risk of malfunction, so the power is turned off at this time. In this power-off, the level of the output terminal 04 of the CPU 61 becomes H, so that the power supply holding circuit 68 becomes inactive, and the LE
This is done when D109 stops emitting light.

(2) When in P, F, (power focus) mode.

When in the P, F mode, as is clear from FIG. 10, the routine goes to the POWER routine shown in FIG. 12, so the battery check BCHK2 operation is performed first. As shown in FIG. 16, this battery check BCHK2 operates by comparing the monitor voltage V and the voltage Vt after the INBATT operation.
"13^], ≦Vt, if BAT, the power is turned off as in the above BAT, C mode, and if vDAT > VL, the voltage vBAT and Vn are further compared, and "II > Vl) AT If there is, that is, if VBAT is Vll, set the DUTY flag to 1, and vII ≦vBAT.
If there is a problem, clear DUTY 7-7 and return.

Thereafter, returning to FIG. 12, it is determined whether or not the P, F, UP operation buttons 16A and the P, F, DN operation buttons 16B have been pressed. First, switch 143
(P, F, UP) is on, switch 144 (P, F
, DN) is off, the distance ring 9 rotates in the near direction, so it is determined whether the close range position Pn has been reached as shown in FIG. A determination is made as to whether or not this is the case. When the near limit is reached, a limit warning LMTALM shown in FIG. 15 is performed. The limit warning LMTALM is issued by the sound switch 21 as shown in the sound generation pcv2 routine in FIG.
is on, the output circuit 70 is activated and the PCV
181 emits a warning "bee beep" in the oscillation mode of oscillation 2, waits, and returns to A1. In this case, the above 8th
A warning display is also performed by emitting light from the LED 155 in the figure.

If the near limit has not been reached, the pronunciation P shown in Figure 33
When the CVI routine is entered and the sound switch 21 is turned on, the sound generation circuit 70 is activated and the PCV 18 is activated.
1 makes a "beep" sound in the manner of oscillation 1. If the sound switch 21 is off, no sound is produced and the process returns. After this, the direction flag is cleared and the motor drive MDRI
The routine moves to V1 (see Figure 27), where the motor is driven by IADR over a short distance, and after that, the count number N is set in the ADR counter 190, and then the switch 143 is turned on or off again. A determination is made. If it is off, it returns to A, and if it is on, after a wait, a count of (N-1) is performed, which becomes N
It is repeated until it becomes -0. If it becomes N-0, it is again determined whether the limit is near or not. That is,
If the switch 143 is turned off before it reaches N-0, it will return to Al, and even if it reaches N-0, the switch 143 will not turn off.
If continues to be on, the next near limit is determined. After this, if the near limit is reached, the above-mentioned limit warning LMTALM occurs, and if the near limit is not reached, the motor drive MDRIVI is followed by a wait, and then P and F.

While the UP is being performed, the motor drive MDRI V 1 is operated until reaching the near limit.

Now, to describe the operation of the motor-driven MDRI V1, as shown in FIG.
After HK2 is performed, it is determined whether the direction flag is 1 (infinite) or 0 (close). If the direction flag is 1, the far direction drive MDI routine (described later) is performed.
(See Figure 28). If the direction flag is 0,
It is determined whether the output of the ADR switch circuit 71 (hereinafter referred to as ADR output) is at H level. ADR output is low
If the level is at the near limit, the motor brake will be applied, but if the near limit has not been reached, after the near direction IADR drive MDSI (see Figure 29) operates,
Return to l1. If the ADR output is at H level, then the above MDSI operation is repeated until the ADH output reaches L level. When the ADR output reaches the L level, the motor brake is applied, and after a wait, the motor returns.

Regarding the near direction IADR drive MDSI, as shown in FIG. 29, first, the motor drive flag is inverted, and it is determined whether the motor drive flag is at H level or not. Assuming that the motor drive flag is currently at H level, for example,
The motor 23 is driven in the near direction, waits, and then turns off and returns. In Fig. 27, ADH
This MDSI operation is repeated until the output reaches the L level, so in the second operation, the motor drive flag goes to the L level and the motor is braked.

Then, it is determined whether the DUTY flag is 1 or 0, and if it is 1, then ■II>vBAT, so the motor is turned off after 2 waits, and if it is 0, ■II≦vBA
Since it is T, the motor is turned off after one wait.

That is, the on/off duty ratio of the motor is changed in accordance with the voltage of the battery 75 to vary the time during which the brake is applied. In the end, in the operation of MDRIVl in FIG. 12, the motor repeats on and off operations in the near direction in MDSI to drive for IADR.

In other words, by performing the above-mentioned operations, when the P, F, and UP pushbuttons 16A in FIG. , each time the operation is performed, a sound is generated in the form of oscillation 1. When the push button 16A is continuously pressed, the distance ring 9 will rotate continuously. When the near limit is reached, a sound is generated in the oscillation 2 mode to warn the user of the near limit, and at the same time, the motor is braked to stop the distance ring 9 from rotating.

Next, returning to FIG. 12 again, switch 143°144,
That is, when P, F, UP, P, F, and DN are all off, if the REL (release) signal is guided, it returns to AI, and if it is not guided, it becomes a power-off state. When switch 143 is off, switch 14
4 is on, the distance ring 9 rotates in the far direction, so the routine shifts to the infinite limit check FLCHKI shown in FIG.

In FLCHKI shown in FIG. 13, a long distance limit (hereinafter referred to as a long limit) is first determined. If the far limit is reached, the limit warning LMTALM is performed, but if the far limit is not reached, the PCVI operates to generate a sound in the oscillation 1 mode, and the direction flag is set to the infinite direction (1
).

After this, the program operation of the motor drive MDRIVI is started. The operation of MDRIVI at this time is the 28th
As shown in the figure, since this is a program operation of the sequential drive MDI, it is first determined whether or not the ADR output is at the L level. If the ADR output is at H level and has reached the far limit, brake operation BRK1 is performed, but if it has not reached the far limit, far direction IADR drive MDS2 is performed.
After the operation (see FIG. 30), the process returns to A12. ADR
When the output is H level, far direction IADR drive MD
After S2, when the ADH output becomes H level, it is determined whether or not the far limit is reached, and if it is the far limit, the brake operation BRKI is activated, but if it is not at the far limit, the ADR is activated.
The operation of MDS2 is performed until the output reaches the L level, and when the ADR output reaches the L level, the brake operation is performed.

In this way, after the above MDRIVI operation, A
A count number N is set in the DR counter 190. After this, if the switch 144 is off, it returns to A1, and if the switch 144 is on, it waits and returns to (N-1).
is counted, and this is repeated until it reaches N-0.

If N-0, as shown in FIG. 14, the far limit is determined, and if it is the far limit, the above LMTALM
If a warning is issued and the far limit has not been reached, as long as the switch 144 is on, the wait operation is repeated after MDRI V 1 until the far limit is reached.

Therefore, the pushbuttons IBB of P, F, and DN in Fig. 1
When operating , the distance ring 9 rotates by a small angle in the long distance direction when operated singly, and generates sound in the manner of oscillation 1 each time it is operated. When the push button 16B is kept pressed, the distance ring 9 will rotate continuously. When the far limit is reached, a sound is generated in the mode of oscillation 2 to warn the user of the far limit, and at the same time, the motor is braked to stop the distance ring 9.

Now, regarding the far direction IADR drive MDS2 in the far direction drive MDI, as shown in FIG. 30, like the near direction IADR drive MDSI, first, the motor drive flag is inverted, A determination is made. When the motor drive flag is at H level, the motor 23 is driven in the far direction, and after waiting, the motor 23 is turned off.

When the motor drive flag is at L level, the motor 23 is braked. At this time, if the DUTY flag is 1, the motor 23 is turned off after two waits, and if it is 0, the motor 23 is turned off after one wait. That is, even in the case of this continuous driving, the time during which the brake is applied differs depending on the state of the battery monitor voltage VB^.

(3) When in SIN, AF (single autofocus) mode.

In the SIN, AF mode, as is clear from FIG. 10, the AFSINI program operation shown in FIG. 17 is performed. In AFS INI, after battery check BCHK2, it is determined whether the REL signal is on or off, and if it is on, AFS IN2 as shown in FIG.
After the operation, the power is turned off, and if the REL signal is off, the AFSTAT pushbuttons 16A and 16B, that is, the switches 143 and 144 are off, the power is off, and the AFSTAT switches 143 and 144 are turned off. If any one of them is on, the power is turned off after the operation of AFS IN2.

The operation of AFS IN2 is as shown in FIG.
After the operation of AFSIN3 (see Figure 20), it is determined whether the LL (low light) flag is 1 or 0, and if it is low light (-1), ! First LED of notification circuit 67
154 and the second LED 155 are both turned on and a low light warning is displayed. If it is not low light (-0
), it is determined whether the AF status flag is 0 or not. If the AF status flag is not 0, that is, if any one of the short distance flag, subject movement flag, and low contrast flag is 1, the PCV2 warning operation is performed and the short distance warning, subject movement warning, and low contrast flag are activated. A contrast warning is issued by sound and the process returns. These warnings are also issued by the warning display circuit 67. If the AF status flag is 0, the PCVI
After the user is informed that the sound generation operation is normal, the process returns after the WIND operation.

The operation of WIND is as shown in Fig. 19.
or a motor drive device) is connected, an output that turns on the winder is generated.

Now, to describe the operation of AFSIN3 in FIG. 18, as shown in FIG. 20, after the RETRY flag is cleared, the AF small loop AF count number is set. Thereafter, after the AF status flag is cleared, routine AF operation for im distance is performed. As is clear from FIG. 31, this AF program operation involves loading the result of A/D conversion of the CCD output from the focus sensor 28 into the CPU 61 (INCCD), converting it into an algorithm, and performing a low contrast test. . After this, return to Figure 20, and if the contrast is low, subtract 1 from the AF small loop count and return to A5, repeat this process, and when the AF small loop count becomes 0, the low contrast warning display will be displayed. It is done.

This warning display is made by the LED 156. If the contrast is not low, the ADH operation shown in FIG. 32 is performed. As is clear from FIG. 32, this ADR operation involves loading the A/D conversion result from the zoom information detector 42 into the CPU 61 (INZOOM),
Taking this zoom factor into account, it is calculated how many ADRs the motor 23 (range ring 9) should be driven. If the ADR value calculated in this way is smaller than a certain maximum value MAX, the ADR value is
The DR value remains the same, but if the ADR value > MAX,
This ADR value is forcibly set to ADR value - MAX. After this, a comparison is made between the ADR value and the PCALL value. The PCALL value is a threshold for determining whether autofocus is used or the extremely accurate atll distance is in a steady state. If the amount of movement from focus is Δd, then the number of pulses required to move this Δd is the be. ADH<P
If it is CALL, the motor is driven by low-speed pulses by MDRIV8 shown in FIG. ADR≧PCA
If it is LL, the RETRY flag is 0 at the time of the first distance measurement calculation, so after the RETRY flag is set at this time, the process goes to A3 shown in Figure 21, where the current ADR value is stored, and the ADR value shown in Figure 24, which will be described later, is set. The motor is driven at high speed by MDRIV4. Then, subtract 1 from the AF small loop count number, return to A4, and adjust the AD based on the distance measurement AF again.
An R value is calculated. After this, the RETRY flag is set to 1, so go to SIN32. By repeating such operations, the current ADR value and the previous ADR value are compared at SIN32. If the current ADR value≧the previous ADR value, it means that the focusing operation of the photographing lens cannot follow the subject movement speed at this time, so a subject movement flag is set and a warning display of subject movement is performed. This warning display of subject movement is performed by emitting light from an LED 154 in a warning display circuit 67 in FIG.

If the current ADR value is less than the previous ADR[, then the current ADR value is memorized, and the above M
Repeat the operations below DRI V4.

Note that the determination of the warning display for subject movement is not necessarily limited to comparing the current ADR value and the previous ADR value as described above, but, for example, comparing the previous ADR value x (1/2) and the current ADR1ii. However, the ADR value this time is the previous AD
If the R value is not within 50%, the above warning may be displayed.

Here, to describe the motor low-speed pulse drive MDRIV8 in the routine of AFSIN3, the second
As shown in Figure 2, after performing battery check B CHK 2, it is determined whether the above ADR value is 0 or not. If the ADR value is -0, the AF status flag is cleared and the ADR value - Otherwise, ADR counter 1
Set the above ADR value to 90. After this, if the direction flag is 0 (close direction), the motor 23 is driven in the short distance direction, and if the direction flag is 1 (infinite direction), the FDR is driven.
It moves to the IVI routine and is driven in the far direction. By driving the motor 23, a hardware subtraction is performed from the ADR value set in the ADR counter 190 each time an IADH pulse from the ADR switch 71 is input. If the direction flag is 0 and the near limit is reached, motor 2
After the brake is applied to 3 and the ADR value becomes -0, the process returns to A7 and the AF status flag is cleared. At this time, if the ADR value is 0, the short distance flag of the AF status flags is set and the short distance #1 warning is displayed by the LED 155 of the warning display circuit 67.

When the direction flag is set to 1 and the mode shifts to FDRIVI (far direction drive), this FDRIVI is at the far limit, as shown in FIG. Return to A7 inside and A
The F status flag is cleared. If the far limit has not been reached, the motor is driven in the far direction, and after waiting, if the remaining ADR value is 5ADR or more, it returns to A9 in Fig. 22, and is driven further in the far direction, and the remaining 4AD
When reaching R, the motor is braked, and after a wait, A8 is reached. Then, the motor is driven in the far direction until the count ends, and the remaining ADR value is 2ADR, IAD
When reaching H, the brake is applied in the same way each time, and the motor is driven by low-speed pulses. Then, when the count of ADRli set in the ADR counter 190 ends, the motor brake is activated. After the wait, if the overshoot exceeds the predetermined position, the amount of overshoot is set in the ADR counter 190, the direction flag is inverted, and the motor drive of MDRIV8 is started again.

Furthermore, during the operation of MDRI V8, when the direction flag is 0 and the motor is driven in the near direction, A6 in FIG.
Then, as in the case of far-direction driving, the motor is driven in the near direction until the remaining ADR value reaches 4ADR, and when the remaining ADR value reaches 4ADR, the motor is intermittently braked and decelerated, and when the count ends, Stop at. At this time, if there is an overflow amount, the direction flag is similarly inverted and the MDR1
(2) Operation 8 is performed.

Regarding the operation of the motor-driven MDRIV4 in FIG. 21, as shown in FIG.
The value obtained by subtracting the P minus value from the R value is the ADR counter 19.
Set to 0. The P minus value is a value that is subtracted by 1,000 bales in consideration of overshoot. As a result, if the set value of the ADR counter 190 is not 0, the direction flag is determined, and when the direction flag is 0 (closest direction), the motor is driven in the near direction. The motor is driven in the near direction and the ADR counter 1
When the set value of 90 reaches O, the brake operation BRKI shown in FIG. 26 is performed, the motor 23 is braked, and the lens drive is stopped. Even if the set value of the counter 190 does not reach O, if it reaches the near limit, the motor is braked at this time as well. Also, when the direction flag is 1 (infinite direction), the far direction limit check DLEF
Shift to TI program operation.

The operation of the far direction limit check DLEFTI is as follows.
As shown in the figure, first, it is determined whether or not the far limit is reached, and if the far limit is reached, the brake BRKI is operated, or if the far limit is not reached, the low speed zone (position Pr in Figure 5) is performed. It is determined by the delay coded signals from the zone switches 38 (145) and 39 (146). If it is not in the low speed zone, the motor 23 is further driven in the far direction and returns to A10. When the low speed zone is reached, at this time the MDRI V 1 IADR shifts to the far direction drive, the motor 23 is braked, and after the wait, the Alo
Return to Then, the value set in the counter 190 is 0.
When the motor 23 becomes
rotation stops. Therefore, when the photographic lens is driven in the infinity direction and reaches the zone at the position Pr, the lens drive shifts from a high speed state to a low speed state and the brake is applied, resulting in a smooth stop state at the position Poa. .

(4) When in SEQ, AF (Sea fence autofocus) mode.

In the SEQ, AF mode, as is clear from FIG. 10, the AFSEQ routine shown in FIG. 35 is performed. In AFSEQ, battery check B
After CHK2, it is determined whether the REL signal is on or off, and if it is on, the operation shifts to AFSIN2 (see FIG. 18).

That is, in this SEQ and AF mode, when a release signal from the camera is input, SIN.

AF mode operation is performed. When the REL signal is off or after the above AFSIN2 operation is performed, the AF status flag is cleared and AFSTAT
When either of the switches 143, 144 is turned on, the operation of AFSIN3 (see FIG. 20) is performed. After this, it is checked whether all the AF status flags are cleared, that is, whether the low contrast, close distance, subject movement, and low contrast flags are cleared. If they are cleared, it is determined that the focus is OK. Then, the PCVI operation, that is, the sound of oscillation mode 1 is performed to notify the user that focusing has been performed, and the WIND operation is performed. After this, the process returns to A13, so while either the switch 143 or 144 is turned on, the focusing operation is performed continuously, and the sound is generated each time the focus is achieved, and if the winder is connected, Trigger output is sent sequentially to the winder.

When both the AFSTAT switches 143 and 144 are turned off, the above-mentioned focus OK check is performed, and if the focus is OK, it is determined whether the REL signal is on or off, and if the same signal is off, the power is turned off. leading to off. After turning off the switches 143 and 144, if the focus is not OK, the PCV2 operates, that is, the sound of oscillation mode 2 is performed to warn the user and the power is turned off.

As described above, according to the present invention, the following excellent effects are exhibited.

That is, in the present invention, when the scheduled driving amount of the photographing lens based on the output of the focus detection means is greater than or equal to a predetermined value, the photographic lens is driven at full speed up to the last minute, and when the expected driving amount is less than the predetermined value, the photographing lens is driven at full speed. Since the motor is driven at a duty ratio that changes according to the program, even if the motor drive speed is set to a high speed, it can be stopped reliably without exceeding the planned position. Therefore, it is possible to provide an automatic focus adjustment device that eliminates the conventional problems.

[Brief explanation of the drawing]

1 to 4 are respectively a perspective view, a back view, a side view, and a schematic cross-sectional view of a lens barrel having an automatic focus adjustment device showing one embodiment of the present invention, and FIG. 1 is a perspective view of the distance Mf'A, FIG. 6 is a perspective view of the zoom information detector in FIG. 4, and FIGS. 8 is a front view of the aperture interlocking switch before and during aperture operation, FIG. 8 is an electric circuit diagram of the lens barrel shown in FIG. 1 above, and FIG. 9 is an electrical circuit diagram of the lens barrel shown in FIG. 8 above. Flowchart showing the operation of the g supply circuit. FIGS. 10 to 35 are flowcharts showing the program operation of the CPU in FIG. 8 above. 15 (141, 142)...Mode selection switch (
Mode switch) 16A, 16B (143, 144)...Operation button 38.39...Zone switch (zone signal generating member) 20......Photography Lens 21...
......Sound switch 22.103...
...Signal pin 23 for release...
·motor

Claims (1)

[Claims] In an automatic focus adjustment device having a focus detection means and a lens drive motor that drives a photographing lens according to the output of the focus detection means, a first drive mode of full speed drive and a power-on of the motor are provided. The lens drive motor drive means has a second drive mode in which the brake is driven at a duty ratio that changes according to a predetermined program, and a scheduled drive amount of the photographic lens is predetermined based on the output of the focus detection means. drive control means for performing distance measurement again after executing the first drive mode until immediately before when the planned drive amount is equal to or greater than a predetermined value; and for executing the second drive mode when the planned drive amount is less than or equal to a predetermined value; An automatic focus adjustment device characterized by comprising the following.