JPS5936205A - Automatic focusing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lens control method, for example, a lens control method suitable for driving a lens in automatic focusing and the like.

Conventionally, a method of servo-based AF has been proposed for this glaze AF, but incorrect distance measurement may occur during high-speed movement, especially when moving the lens at high speed or using a low-speed 5 sensor. Because of this, it was not possible to create a slow API.

A system that drives the lens by measuring the distance twice.
, the lens movement is exactly 1i'eed −
This makes it difficult to monitor the amount of movement, especially for cameras with interchangeable lenses. That is, it has been difficult to perform high-speed and stable control for interchangeable lenses that have lenses that move differently and have different driving forces. In addition, a special signal is required for controlling the lens end (mount), and especially when different control is required at the near end and infinity end, it is also possible to monitor the amount of movement including the error of the connection signal. Easy-to-use AF system that allows you to quickly focus and search when distance measurement is not possible at all.
stem f: It is possible to realize it.

Furthermore, it is possible to configure an easy-to-use system at the end so that such a selection is possible, for example, even when distance measurement is not performed over the entire area.

Hereinafter, one embodiment of the present invention will be described with reference to the attached drawing f.

In Fig. 1, 1 is a photographing lens, and the lens 1 is moved back and forth with respect to the optical axis 0 as shown by arrow 3 so that the image of the object is correctly formed on the intended imaging plane 2. However, in order to detect the focus, images at a position equivalent to the planned imaging plane 2 and positions before and after the image plane 2, for example at positions 4, 5, and 6, are converted into electrical signals using a sensor. By performing comparison processing, defocusing for the planned imaging plane 2 is performed.
to move and stop the lens 1.

Next, in FIG. 2, the images at positions 4, 5, and 6 mentioned above are converted into electrical signals by the sensor unit 11, and this is applied to the focus detection unit 12 to detect the amount of defocus. Focus and defocus are determined and the drive instruction unit 1:3 correctly determines 9. M has a configuration in which the driving amount for quick focusing is calculated and the driving system 15 is controlled by the driving control unit 14.

Next, an example of the focus detection unit 12 will be explained using the third (see 1). The sensors are arranged to look at the same area, and depending on the brightness (in order to stabilize 'u!L current is applied to generate a potential on the line 26 that becomes low depending on the brightness of the distance measurement area.This brightness signal is differentially amplified with the reference potential by the resistors 27 and 28 and sent to the line 30. A signal that goes high depending on the brightness is generated.This signal controls the constant current circuit 31, 32, 33, and the brighter the current, the more current is applied to the point 34, 35, 36, depending only on the visibility of each position. , brightness gives rise to unrelated beliefs.

In this way, the predetermined focal plane and the front and rear sharpness signals are transmitted through the amplifier 37.
．． Increased by 38.39 [IJ line 40.41.4]
2, it is possible to obtain sharpness signals in front of the intended focal plane, in front of the intended focal plane, and behind the intended focal plane, respectively.

Of these three signals, two signals on lines 40 and 42 are applied to a differential amplifier 43 to obtain the difference in sharpness between the images before and after the intended image forming plane, and at the same time, an addition amplifier 44 is applied to Calculate the sum of the sharpness of the image of the subject, give both of them to the divider 45, and divide the difference by the sum to normalize the sharpness of the subject's own image and calculate the sharpness of the image from the front and rear positions of the planned image plane. A signal proportional to the imaging position, that is, a defocus amount is output to the terminal 46.

At the same time, the comparator 47 outputs the polarity, ie, high when the front side is clearer, and low when the opposite side is defocused (ie, when the rear side is clearer) as the defocus direction. However, the above-mentioned defocus amount of the terminal 46 can only be determined as positive 1 to 1 when the imaging point is at the internal division point of the front and rear sensors 21.23, and If the image is significantly blurred, defocus cannot be determined correctly. For this purpose, a large value of the front and rear sharpness is determined on the line 52 using the diode 49,50 and the resistor 51, and this is compared with the signal on the line 41, that is, the sharpness signal to the planned focal plane using the comparator 53. When the sharpness on the planned focal plane is lower than the sharpness on the front and rear planes, that is, when the image plane is located at the internal division point of the front and rear sensors 21 and 23, in other words, when the sharpness of the terminal 46 When the defocus amount is a determined value, a high signal is output to the 54 terminal.

In addition, since the output of each sensor 21, 22, 23 may be uncertain in an extremely large overflow condition, in order to detect this, each sensor output is applied to a circuit consisting of diodes 55 to 57 and a resistor 58. The maximum clarity is determined, and this signal is compared with a reference value by a resistor 59°60 using a comparator 61.
If there is sufficient clarity, the output is set high, and the AND gate 62 sets the output high when only the direction is determined outside the above-mentioned range, and the terminal 63 is set when only the direction is determined. get high.

In addition, in the case of a large scale where the signal cannot be accurately obtained at all, the low output of the comparator 61 is inverted by the inverter 64 and a high level is output to the terminal 65 to distinguish that the signal is uncertain. It is structured in such a way as to encourage you.

In addition, when it is dark, the overall response becomes slow, so in order to stabilize the response, the brightness signal of the line 30 mentioned above is also used while driving the lens.
That is, since there are many things that can cause erroneous distance measurement during motor drive, a signal that goes high is applied to terminal 69 from the drive control unit (described later) during drive, and during that time the voltage controlled oscillator 67 is cleared to eliminate the erroneous strobe pulse. Try to prevent it from happening. In addition, when an accumulation type sensor such as a COD is used as the sensors 21 to 23, erroneous accumulation can be prevented by entering a new accumulation sequence when the drive signal goes low.

In any of the other embodiments of these signals, in a distance measuring device using an accumulation type sensor such as a COD, the pulse at the terminal 68 corresponds to the timing at which the distance measurement result is confirmed.

In addition, even with completely different distance measuring devices, such as the image shift method, there is a limited area in which the defocus can be calculated accurately, and if there is a large shift, the accuracy of the meter will decrease, and the image may become blurred, etc. If the focus is large (for example, in the case of a flat object), the calculation of the direction is no longer necessary, and a similar signal is generated.

Next, referring to FIG. 4, an example of the drive instruction unit 13 is shown as h1.
To clarify, in the same figure, the calculation timing signal from the focus detection unit 12 (if only the terminal 68 direction is confirmed, the confirmation signal (terminal 63 output) is sent to the terminal 103, and the direction No. 46 (terminal 48 output) is provided to terminal 104.

Further, in the case of an area in which = can be calculated, the determination signal (output from terminal 54) is obtained at terminal 1 ( ) 5, and the current defocus - (output from terminal 46) terminal 106 is obtained.

Of these, the defocus tW is converted into absolute I+U by an absolute value circuit 107, and further converted into a digital value by a converter 108. Here, when in focus, that is, within the AF (autofocus) convergence range, the absolute value is smaller than a certain value, so the comparator 1
11, the output is sent to the AND gate 112 together with the defocus value determination signal from the terminal 105. This AF convergence range may be widened by the aperture value of the lens, so in that case, the resistor By increasing the convergence level based on 109 and 110, it is possible to converge more quickly and complete AF, thereby eliminating meaningless convergence.

The above calculated values are taken in in synchronization with the strobe signal given to the terminal 101 mentioned above when each operation is determined, and AF' is performed. When a pulse is generated, a pulse is generated on line 15 as a signal update or a pulse to clock the D-latch 116 to capture new driving data. And if it is outside the AF convergence range mentioned above, that is,
When driving the lens, the signal on the line 113 mentioned above is inverted by the inverter 117, and the signal that goes high when a drive is requested is synchronized with the updated clock on the line 115 mentioned above, and when the signal is determined, it is sent to the terminal through the D-flip-flop 118. 119 and 120. The lens is driven by this NOI signal, and when the lens drive is finished, a high signal from the drive end signal terminal 121 or a high signal from the lens limit signal terminal 122, which will be described later, is sent to the 'tOR gate 12.
When the drive ends or when the drive goes to the limit, the signal that goes high by inputting the signal to the flip-flop 1
18 to stop driving and perform subsequent processing based on the next data.

Since the distance measurement data as described above is held in the launch 116 when each data is determined, it is necessary to drive the lens based on this data.

For example, if the defocus amount is also determined, the line 124 becomes high, and the output of the OR gate 125 also becomes high, opening the AND gate 126 (at this time, since the uncertainty signal at the terminal 102 is low, the signal at point 127 is also low. and
Therefore, D-7 Risopflots, B128 is clear line 1
Since 29 is also low, the AND gate 13o is closed) Information on the determined direction (sign) of the terminal 104 is given to the terminal 132 through the OR gate 131'fr, and the lens is instructed to be driven in this direction.

D flip-flop 133 is used to store the previous indicated direction and is clocked by the signal on line 115 mentioned above.

Now, if the instruction is in the same direction as the previous time, the exclusive OR gate 134 (exclusive OR) outputs a low signal to the line 135, regardless of the direction, so 1/2 of the input is output. Since the AND gate 137 is open due to the high level of the above-mentioned line 1240 signal (at this time, the AND gate is connected to the line 139 because the "direction only determination" of the terminal 103 is low).
(and the AND gate 140 is closed by the row of line 129 mentioned above)
The required defocus amount is instructed to the terminal 142 through the terminal 41f.

Note that the division circuits 136 and 143 output 1/2 of the input.
is configured so that the connection is shifted by 1-bit depending on the high level of the control terminal.

The D-flip-flop 133 and exclusive OR gate 134 reduce the current defocus instruction when the direction is different from the previous one, so that even if defocus is incorrectly or incorrectly instructed, it will converge. (1/2
This circuit is very effective because it can quickly converge without preventing oscillation. In other words, if the distance measurement result is in the opposite direction to the previous one,
Exclusive OR gate 13 regardless of its direction
The high output of No. 4 operates the divider circuits 136 and 143 to reduce the current drive requirement by half, thereby preventing oscillation near the in-focus point.

For example, if only the t and I-f direction is confirmed and the defocus instruction sound is not accurate, terminal 10!5 is bow and terminal 103 is high.
When the terminal 102 goes low, the input 124 goes low, the line 139 goes high, and the lines 127 and 129 go low, so a drive request is made in the nine directions based on a determination of a certain distance. Here, the ° direction is O due to the high of line 139.
The configuration is such that the output of the R gate 125 is set high, and the determined direction is outputted to the direction indicating terminal 132 through the AND gate 126, with the AN'D gate 130 closed, and further through the OR gate 13.1.

Further, the required amount of driving is determined by giving a code corresponding to 2u as a constant (which may be changed depending on the lens, etc.) using the constant setting device 144, and calculating the value that does not exceed the defocus range during driving. Piece circuit 143 J/C is used to prevent liftoff, and if the direction is the same as last time, the value remains as is.If the direction is different from the previous time, half the value is applied.N'D gate 138'
ff: The AND gates 137 and 140 remain closed, and the output is output as a motion amount to the terminal 142f through the OR gate 141.

If the direction is also uncertain, the terminal 105 is low, the terminal 103 is low, and the terminal 102 is -i, so that the line 124 is low, the line 139 is low, and the line 124 is low, the line 139 is low, and the
7 becomes high. If this direction is also indeterminate (I * constant), there is a possibility that it may occur due to a momentary accident (for example, camera shake),
When the focus is essentially uncertain, a search is performed over the entire area of the lens to adjust to a focal point that is significantly off. For this reason, starting a search operation due to flash blur etc. tends to be unstable in terms of usability, and starting a search operation - [KI4 The focus may move away from the fixed focus point and lose the focus point. The following stabilization circuit is used to prevent this.

That is, in the case of - times uncertainty, the flip-flop 128 is released from reset due to the high level of line 127, but line 12
9 does not go high, AND gates 126 and 130 are closed, so terminal 132 becomes low, and AND gates 137, 138, and I 40 are also closed, so OR.
A drive request amount of zero is output to the terminal 142 through the gate 141 so that the lens is not driven. However, if two or more consecutive hits are confirmed, the line 129 goes high by setting the flip-flop 128, and by opening the AND gate 140, the search lens drive constant from the constant setter 45 is set. ), the entire area is searched as quickly as possible, and the amount that does not miss the in-focus point, that is, does not pass through the direction discrimination range, is determined through the OR gate 140. Terminal 142 J: Outputs as a drive request amount and makes a drive request.

The direction is determined by a T-flip-flop 146 that is inverted by an end signal applied to a terminal 122, which will be described later, when the lens is driven to the limit for full-area sampling, and the indicated direction is determined by an AND gate 130 and an OR gate 1.
31 to the drive direction terminal 132. During a search, this flip-flop performs a search with a constant drive amount until the lens reaches a limit, and generates a signal that goes high at the limit terminal when a search is instructed, as described above.

Next, an example of the drive control unit 14 described above will be explained with reference to FIG.
Drive instruction it given to terminal 201 from <terminal 14
2 output) is applied to the terminal 202. This is a control unit that drives the lens in the drive direction indicated by the + direction signal (output of terminal 132) only while the drive signal (output of terminal 119) applied to terminal 203 is high.

The lens side has a motor as described later, which drives the lens to extend and retract.It also has a means for generating a pulse 2 signal in relation to the lens movement to monitor the movement of the lens. The phase of the pulse signal at the focus plane may change due to design or zooming, so the code for this is (focus movement amount)/(
1 pulse interval) is held by a resistor or variable resistor. A signal of (focus movement amount)/(one pulse interval) from the lens, which will be described later, is given to a terminal 204 and read out as a voltage related to the movement amount through a constant current circuit 205.

This voltage is passed through the A/D converter 206 to the line 207 (
The larger the amount of movement (for example, proportionally), the larger the code (for example, proportionally) is converted.

The conversion characteristics of the A/D converter 206 do not need to be linear, and can be set arbitrarily in relation to the lens side signal, but in this embodiment, the opening of this lens side signal is The amount of movement will be described later! It is used to prohibit Ih.

Now, in the unit 14 shown in FIG. 5, we will first explain the lens drive monitor circuit section.
A pulse-like signal corresponding to the driving of the lens is converted into a voltage signal by a resistor 209, and in order to pick up one side of the signal, a capacitor 210 and a resistor 211 are used to constantly change the high C pulse signal at a point 212. (falling to the GND level), a signal that becomes low for a moment d (cR time constant) is obtained, and is processed by the amplifier 213 as a change pulse. Diode 214 is provided to prevent point 212 from becoming an abnormally high voltage due to a reverse change. Further, the time constant provided by the resistor 211 and the capacitor 210 prevents chattering of the pulse generation source.

Next, to explain the arithmetic circuit section, the circuit section is connected to the terminal 20.
This circuit determines whether the lens has been moved by the required defocus amount of 1, and since the amount of movement per pulse interval is obtained on line 207, the movement t up to the present is stored in the D-flip-flop 215. Add this value to the movement M per pulse interval in the adder 216.
17 outputs the amount of movement when the next pulse comes and performs the requested movement! (signal at point 201) is compared with the magnitude comparator 218, and when the amount of movement when the next pulse arrives is greater than the requested movement amount, a high signal is output to the line 219, and the AND gate 220
is being driven, that is, when the terminal 203 is high, the terminal 221
A high full output is output to send a signal indicating that the movement has been completed by the required movement amount to the drive request circuit described above, causing the drive to stop and the next distance measurement to be performed. The above addition is performed using D-flip-flop 2.
15 is reset when the drive signal at the terminal 203 is low, that is, when it is not driven, and the content of the flip-flop 215 is updated by the output of the amplifier 13 for each pulse, and the amount of movement up to the same pulse is changed. are added in such a way that the addition results are reloaded.

By adding each pulse in this way, compared to first calculating the required number of pulses by multiplication and division, the configuration can be realized only by addition and subtraction, and since the time interval of the pulses is based on mechanical movement, there is enough time between the pulses. Since it can be calculated, it becomes possible to control movement more easily and easily than by first taking a long time to perform sophisticated calculations using multiplication and division.

Next, to explain the lens limit detection circuit section, first, when not driven, the terminal 203 is low, so the output line 223 of the inverting input OR gate 222 becomes high, and the frequency divider 224 is reset to R8 - the flip-flop 225 is reset. be done.

Therefore, the Q output of the flip-flop 225, ie, the end signal terminal 226 becomes low. -Terminal 20 when driving the blade
3 becomes NO, so that the output of the inverting input OR gate 222 remains unchanged unless the output from the amplifier 213 described above changes to low (that is, the pulse signal related to lens movement falls to the GND level). becomes low and the frequency divider 224 is cleared and starts counting pulses from the oscillator 227. This counter outputs a carry output on line 228 all high when it has counted only the side indicated by the signal at point 207. That is, even if a pulse is generated in connection with driving the lens, the carry output is output when the lens does not move beyond the specified extension even after a certain predetermined period of time has elapsed, that is, the pulse does not come, and the flip-flop 225 is set. terminal 22
6, outputs a high signal to indicate that it is a lens liquid. Of course, if a pulse comes within this fixed time, amplifier 2
Since the output of 13 changes to low, the inverting input OR gate 222 is turned off.

In this way, by detecting the lens limit based on the presence or absence of changes in lens-related pulse signals, one signal line for drive monitoring is sufficient, and depending on the type of lens, the interval between the generated pulses at the lens focus position can be adjusted. Even if the frequency is changed, the frequency division ratio of the frequency divider 224 is changed by the resistance cord of the terminal 204 mentioned above, so the lens limit detection ability can always be changed according to the defocus in terms of the focal plane, and therefore, depending on the lens. Even if the pulse interval changes, appropriate determination can be made accordingly.

This limit signal causes new sampling to be performed through the OR gate 123i in FIG. 4, and inversion in search mode is performed by the T-flip-flop 146 to search the entire area.

Next, to explain the lens driving force control circuit, this circuit compensates for differences in motor driving force, speed, etc. depending on the lens, and also for the aforementioned difference in lens-related pulse intervals. It is the circuit part of Nodame,
The output of the reference oscillator 230 is connected to the signal on the line 207 mentioned above,
That is, a variable frequency divider 2. ,． Terminal 23 by 38,1
2. A phase comparator with a phase-locked loop (with a low-pass filter on the output) generates a pulse corresponding to the expected pulse and period for a certain defocus margin.
233 along with the actual lens-related pulse that is the output of the amplifier 213, and generates a high output if the actual lens-related pulse is slower than the expected pulse, and a low output in the opposite case. Through amplifier 235V
By increasing or decreasing the power of the C, 1'υ motor and feeding back to the number that yields pulses similar to the expected pulses, the response speed may change depending on the lens, or the IJ mist detection circuit described above may malfunction. This prevents it from becoming difficult to use. The oscillator 236 has a short interval between lens-related pulses, and is a limiting oscillator with a phase-locked loop to prevent it from firing too quickly, making it difficult to distinguish it from chattering, and making it difficult to control. Comparing the lens-related pulse with the output pulse of this oscillator 236 in a phase comparator 237 (with a low pass filter at the output);
If the lens pulse is abnormally fast, its output is changed to npn-) through the resistor 238.
By turning on i, the speed control (control for constant movement of the focal plane) by the phase comparator 233 described above is restricted to prevent the lens pulse from malfunctioning due to abnormally rapid movement. That is, when the transistor 2390 is turned on, the amplifier 235
The 0 input is lowered, the motor power is limited and the speed is reduced, and different lenses are matched to the drive system.

Next, the motor drive ml+ circuit section will be explained. When the circuit section is not driven, the gate 21 is connected to the low level of the terminal 203.
The output of the inverter 242 is made high and the pnp-transistor 244 is turned off through the resistor 243.

The output of the OR gate 245 becomes high due to the low level of its inverting input, and turns on the +19, λ n-transistor 2-47'' (L-) through the resistor 246. Similarly, since the output of the AND gate 248 is low, the inverter 2
The output of 49 goes high, turning off pnp-transistor 251 through resistor 250.

The inverted input OR gate 252 outputs a high level due to the low level of its inverted input, and the output becomes high through the resistor 253 (n p n -).
Turn on transistor 254. As a result, the transistors 247 and 2540 are turned on and the diode 2 is turned on to prevent the transistor IJ1 from being damaged by the back electromotive force of the motor.
55-258, motor terminals 259 and 260 are short-circuited and a brake ('711 magnetic brake) is applied.

If the lens has not reached the above-mentioned limit, the Q output of the flip-flop 225 is low, so the NAND gate 2
The output of 60.261 is /S.

For example, if the 1Φ direction terminal 202 is No.
When 03 is set to NO and driven, AND gate 248
The output of the OR gate 252 goes high, the transistor 254 turns on, and the inverter 249
The transistor 251 is turned on due to the low output of . Also, since the output of APD gate 241 is low, the output of OR gate 245 is low, so transistor 24
7 is turned off, and since the output of inverter 242 is high, transistor 244 is also turned off. The output (positive) of this amplifier 235 is applied to a terminal 259, and a terminal 260 is grounded by a transistor 254 to drive the motor in the desired direction. If the limit is reached, the output of the NAND gate 262 becomes low, so that the drive is corrected.

When driving in the opposite direction, terminal 202 is low and terminal 203 is low.
Conversely, when the output of the AND gate 241 becomes high, the output of the OR gate 245 becomes high, which turns on the transistor 247, while the inverter 2
Since the output of 42 becomes low, the transistor 244
is also turned on, and O is also turned on due to the low output of AND gate 248.
Since the output of R gate 212 is also low, transistor 2
54- is off, and since the output of the inverter 249 is high, the transistor 251 is turned off. Therefore, the output (positive) of the amplifier 235 is given to the terminal 260,
Further, the terminal 259 is grounded when the transistor 247 is turned on, and the motor is driven in the opposite direction to that described above. If the limit is reached, the output of the NAND gate 26 becomes low, thereby stopping the drive. In both cases, when the drive is stopped due to the low drive terminal 203, the brake is applied as described above. A terminal 270 is a terminal for transmitting a monitor signal of the terminal 208 for limit determination, which will be described later.

Next, the drive system unit 15 will be explained with reference to FIG. The configuration shown in the figure corresponds to, for example, a conversion lens for a -eye reflex camera. In other words, the example shown in the figure is an example in which the photographing lens 301 is moved by the deceleration mechanism 302, 303f, and the motor 304 under the control of the terminals 305, 306, which not only extends the entire lens, but also moves the front lens and some lens groups. A similar focusing mechanism can be realized by movement. here,
a brush 307 interlocked with the lens 301 and grounded;
<The toothed electrode pattern 308 is configured so that the above-mentioned lens-related pulse can be output to the motor terminal 309 according to the movement of the lens, and the resistor 310 connects the entire terminal 311 to (defocus amount)/(1 pulse). Interval) code can be transmitted. This code makes it possible to change this resistance value in response to zooming, for example, and it is possible to compensate for focus movement by transmitting changes in lens movement amount and defocus rate due to zooming. 312 and 3
Reference numeral 13 denotes a top member for extending and retracting the lens. When the lens hits this member, the limit of movement +h is detected by the limit detection circuit in the drive control unit 14 shown in FIG. 5, and the limit is set by stopping the drive. This makes it possible to control the system without using any special switches or the like.

312 and 313 are mechanical limit members for extending and retracting the lens. Before hitting this member, SW 314 is opened on the infinity side to keep the movement monitor signal high, and SW 315 is closed on the close side. The moving monitor signal is always kept low, and the limit detection is performed by keeping the monitor signal unchanged at both ends, and the infinite end and the nearest end can be determined in one line based on whether it is high or low at that time.

As mentioned above, it is possible to adjust the focus, but with this alone, for example, the distance measurement range can be limited to a part of the entire movement.
It is impossible to do fC with the limit open side l (end processing), and for this reason another limit) SWe have to give limit polarity to the tar signal between the lens and the main body using a separate signal line. As shown in Fig. 7, the signal changes as a monitor signal in the intermediate region, and does not change at the end, but also has a polarity of high on the infinity side and low on the close side. This makes it possible to identify the edges.

FIG. 8 shows a circuit for determining the end portion of this reservoir.

(Drive instruction 22 in Figure 4) (1: The unit connected between l and the drive control unit in Figure 5) receives the drive signal from the 119 terminal in Figure 4 to the 401 terminal, and
The search signal from the terminal is received at the terminal 402. Also, ↓
The drive signal from the 32 terminal is received at the 403 terminal, and the 12
The termination signal to terminal 2 is output from the 464 terminal, the signal 'fr to the 121 terminal is output from the 405 terminal, and the signal 270 in Fig. 5 is output from the 405 terminal.
The monitor signal of 406 is received, and the signal of 221 is received by 4
07 terminal receives the 226 signal to the 408 terminal, 2
The signal to 02 is output from the 409 terminal, and the signal to 203 is output to the 410 terminal.

This is done by receiving the termination signal from the limit detection unit shown in FIG.
If the position is close to the inverter gate output high, it is 41/3.
The AND gate output of ζ is made high to perform end determination.

First, when the focus detection unit is driven after determining the direction, etc., the search terminal 403 is low, so the 414
, 415 are closed, and the inverter gate 416 makes this output high, and if there is no change in the pulse signal, the termination signal from the drive control unit described above causes the AND gate output 417 to go high. A borrow signal is generated through the OR gate, and the next distance measurement and adjustment are performed upon completion of driving. Further, the inverter gate 419 inverts the signal when the drive instruction circuit finishes driving, and outputs the signal D-420.
Store the state at the end of driving by counting 7 rip-flops.

The end signal when the direction is determined by this memory becomes infinity information and becomes high when the next drive IAb is made to the infinity side 402
The drive detection signal of the terminal is given to the AND gate of 421, and a signal that goes high when it collides with the infinity position based on the certain direction last time and is about to go to the infinity side next time is generated, and the 422 The LED 424 is lit through the OR gate 423 and the LED 424 is turned on to display an error when the distance is incorrectly measured as described above.

Conversely, when driving to the closest point, the low drive signal of 402 is passed through the inverter gate of 425 to invert it and the previous close end signal is passed through the AND gate of 426, so that the close end is still driven closer to the nearest point. When driving, a signal that goes high is obtained and 424 is displayed as described above.

At the same time, this signal is borrowed (B) to stop the drive.
orrow) or give it to the 404 terminal to drive! 1ilI(i
7 It is also possible to stop it.

In addition, in the case of search mode, as mentioned above, the high of the 403 terminal opens the AND gates of 414 and 415, and in relation to the drive direction terminal of 402, the high of the 402 terminal when driving in the infinite direction and the close f1111 & The I-kai sets the AND gate output of 415 to high, and also inverts the low of the 402 terminal when driving in the close direction with the inverter gate of 425, and in the case of infinite side, sets the AND gate output of 414 to high. do.

In other words, if you are at super infinity, beyond the AF range and are driving to the close side [7] and the time has run out, or if you are at close range or beyond the AF range and are driving to the infinity side. This corresponds to the case where the time has run out, and in this case, this is to prevent the search from returning outside this AF range, which appears to be the pure end position described above, and in these various cases, 427 or The upper gate obtains a high signal 7 in both of these states, and the AND gate of 428 sends this time-out signal to Bo through the OR gate of 418.
It is sent to the drive instruction unit as r r ow, and at the same time it is inverted to a low signal by the inverter gate 429 and the signal is sent to the drive instruction unit as 43.
The 0 AND gate is closed to prevent an inversion search regarding the end point by transmitting the end signal to the drive instruction unit.

Figure 9 shows an example of a lens, where a is a rotating helicoid part and a fixed part, as shown in Figure 10, a has a brush inside the rotating part, C has all its functions, and d has a GND on the fixed side. A conductive part is provided with a conductive part C, and a conductive part C is brought into contact with the FTC brush. e
It is constructed so that it appears at a point.

By kneading, the dough will form a shape as shown in Figure 7.

Also, mentioned above (7) ta enclosure designation sW (314r 315)
? By making it possible to set it arbitrarily, AF within that range can be easily realized.

As described above, the lens is only a single monitor signal,
Enables close and infinite judgment, Focus outside the range
Easy-to-use AF can be achieved with easy connection by enabling warnings and prohibitions, and returning to within the range if the camera is outside the range, and selecting and specifying the AF range that suits the subject.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram for explaining an example of a focus detection method of an automatic focus adjustment device to which the method of the present invention can be applied. FIG. 2 is a system block diagram showing a schematic configuration of each functional system of the automatic focus adjustment device to which the method of the present invention is applied, and FIG. 3 shows an example of the focus detection unit in FIG. 2. 4 is a block circuit diagram showing an example of the drive instruction unit in FIG. 2; FIG. 5 is a block circuit diagram showing an example of the drive control unit in FIG. 2; FIG. 6 is a block circuit diagram showing an example of the drive control unit in FIG. FIG. 3 is a schematic diagram showing an example of the drive system unit in FIG. 2; FIG. 7 is a diagram showing motor signals in the present invention. FIG. 8 is a block circuit diagram showing an example of a limit processing unit in the embodiment connected between units 13 and 14 in FIG. 2. 9 and 10 show the lens barrel in the example of FIG. 8,
In particular, the diagram shows a signal generation section. 1 ;301...Lens, 11...
...Sensor unit, 12...
Focus detection unit, 13... Drive instruction unit, 14... Drive control unit, 1
5... Drive system unit, 304...
...Motor, 213 ...... Multiplier, 215 ...... D-flip-flop,
216...Adder, 218...
. . . Size comparator, 220 . . . AND gate, 123 . . . OR gate, 118.
・・・・・・・・・D-Flip-flop Figure 7 ? Figure 4 Nearest cotton ← → ta l [J Saki

Claims (1)

[Claims] (1) An automatic focusing device characterized in that a lens is driven and controlled by processing a focus movement monitor signal and focus limit information on the same signal line.