JPH0690352B2 - Camera autofocus adjuster - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a subject or a part of a subject to be focused, that is, an object to be focused, whether or not the photographing lens is in focus, and is out of focus. Therefore, the present invention relates to an automatic focus adjustment device for a camera, which repeatedly detects a focus state such as in which direction and how much the shift is made, or a subject distance, and drives the photographing lens to a focus position in focus based on the detected value.

2. Description of the Related Art In such an automatic focus adjusting device, for example, a state in which reliable focus detection with a predetermined accuracy or higher is impossible due to a cause such as low contrast or brightness of an object to which the photographing lens is directed is predetermined. If it is continuously judged for more than time,
Regardless of whether or not the shooting lens is being driven, the shooting lens is forcibly driven a predetermined number of times back and forth over a predetermined range to scan the in-focus state and shoot at a position where reliable focus detection can be performed. Japanese Patent Laid-Open No. 58-63903 proposes a device for restarting the normal automatic focus adjustment operation when the lens arrives.

However, in this apparatus, when it is determined that normal focus detection is unreliable, the photographing lens is always driven, so that, for example, when the photographing lens is being driven toward the in-focus position, the focusing lens is focused. When something crosses in front of the object, or the state of the focused object changes relatively irregularly due to camera shake, the focus is temporarily determined to be undetectable. In that case, there is a disadvantage that the photographing lens is driven in a direction away from the in-focus position, and it may take a long time until the in-focus state is obtained.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention is as in the above-described conventional apparatus even when normal focus adjustment is temporarily impossible when the taking lens is driven toward the in-focus position. It is an object of the present invention to provide an automatic focus adjustment device for a camera that does not take a long time to achieve focus.

Means for Solving the Problems In order to achieve this object, the present invention provides an automatic camera including a forced scanning device for forcibly driving a photographing lens when normal focus detection with a predetermined accuracy or higher is impossible. In the focus adjustment device, a determination unit that determines whether the focus adjustment unit is driving the focusing lens, and a prohibition unit that inhibits the operation of the forced scanning device when it is determined that the focusing lens is being driven. It is characterized by the provision of.

Effect According to the present invention, the forced scanning is prohibited while the focus adjustment based on the previously detected focus detection result is performed,
Forced scanning is only allowed when no focus is being adjusted.

First Embodiment FIG. 1 is a circuit diagram showing an entire camera system to which the present invention is applied. In the figure, (BA) is a power supply battery,
From the line (+ E) directly connected to this power supply battery (BA), control microcomputer (hereinafter referred to as control microcomputer) (MC ₁ ), focus detection and focus adjustment microcomputer (hereinafter referred to as AF microcomputer) (MC ₂ ), display (DSP), buffer (BF), NOR circuit (NO ₀ ), (NO
₁ ), NAND circuit (NA ₁ ) and switch (S ₁ ), (S ₂ ),
(S ₄ ), (TSS), (ASS), (ISS), (MOSS), (UP
Power is supplied to the pull-up resistors (S) and (DOS).

(S ₁ ) is a photometric switch that is closed by pressing the shutter release button (not shown) in the first step. When this switch (S ₁ ) is closed, the output of the NOR circuit (NO ₁ ) becomes “Lo”.
falls to w ", the interrupt pin (i of the control microcomputer (MC ₁₎
The interrupt signal is input to t) and the operation of the control microcomputer (MC ₁ ) starts. (TSS) is a switch that is closed when changing the exposure time (hereinafter called Tv switch), (ASS) is a switch that is closed when changing the aperture value (hereinafter called Av switch), (ISS ) Is a switch that is closed when changing the film speed (ISO) (hereinafter referred to as Sv switch), (MO
SS) is a switch that is closed when changing the exposure control mode (hereinafter referred to as mode switch). When these switches are closed, the output of the NOR circuit (NO ₀ ) is "Low".
, Which causes the output of the NOR circuit (NO ₁ ) to fall to "Low", and in this case as well, the interrupt pin (it) is interrupted and the control microcomputer (MC ₁ ) starts operating.
(UPS) is a switch for increasing data (hereinafter referred to as UP switch), and (DOS) is a switch for decreasing data (hereinafter referred to as DOWN switch). (S ₂ ) is a release switch that is closed at the second step of pressing the shutter release button. (S ₄ ) is a terminal (EE) when the exposure control operation is completed, and a terminal when the exposure control mechanism is charged. It is a reset switch connected to (WE).

2 and 3 are flowcharts showing the operation of the control microcomputer (MC ₁ ). The operation of the camera system shown in FIG. 1 will be described below with reference to FIGS. First,
When the power supply battery (BA) is installed and the power supply from the power supply line (+ E) is started, the microcomputer (MC ₁ ) starts the operation from step # 100 in FIG. First, specify the input mode of each port of the microcomputer _{(P 20) ~ (P 43} ) on either input mode or output mode, the port output mode is designated, "High" or "Low" Set the initial value of. Then, the reference clock (STC to the AF microcomputer (MC _2), etc.
The reference clock (STCL) is not output from the terminal (STCLOU) for outputting L), the flag CDFF is reset, and the content of the mode register MOR is set to "0". here,
The flag CDEF is set when the calculation of the exposure control value is completed. Further, the content of the register MOR is data indicating the exposure control mode. If it is "0", it is the program exposure control mode (hereinafter referred to as P mode), and if it is "3", it is the exposure time priority diaphragm automatic control mode (hereinafter S mode). , "2"
Aperture priority exposure time automatic control mode (hereinafter referred to as A mode), "1" exposure time aperture manual setting mode (hereinafter referred to as M
It is called mode). Next, in step # 107, the film speed ISO100 (S
v = 5) data and set F5.6 as aperture value Avs.
(Av = 5) data, 1/60 sec as set exposure time Tvs
Set the data of (Tv = 6). Next, in step # 110, the exposure mode is P mode and the film sensitivity is ISO1.
00 is displayed on the display unit (DSP), the aperture value and exposure time are blanked, the internal counter of the microcomputer is prohibited from interrupting, and the operation is enabled by interrupting the terminal (it). Stop.

Metering switch (S ₁ ), Tv switch (TSS), Av switch (A
When either SS), Sv switch (ISS) or mode switch (MOSS) is closed, the terminal (i) of the control microcomputer (MC ₁ )
When an interrupt signal is input to t), the control microcomputer (MC ₁ ) starts the operation from step # 0 in FIG. First, in the step of # 0, the terminal (P ₃₀ ) is set to “Low” and the buffer (B ₃₀
The transistor (BT ₀ ) is made conductive via F) and power supply from the power supply line (+ V) is started. Next, the terminal (STCLO
U) to AF microcomputer (MC ₂ ), interface circuit (IN
F), sends the reference clock (STCL) to the motor control circuit (MCC). In the step of # 2, the contents of the counter for counter interruption in the microcomputer are reset, the counter interruption is permitted, the process proceeds to the step of # 3, and the data regarding the interchangeable lens is taken in.

The reading of data regarding the interchangeable lens will be described below with reference to FIG. The block (LE) surrounded by the one-dot chain line in the lower left of FIG. 1 is a circuit block in the interchangeable lens, and (COV) is like a telephoto converter lens mounted between the camera body and the interchangeable lens. , Converter circuit. Specific examples of these circuits are shown in FIG. Control microcomputer (MC _1), when reading the lens data is the "Low" terminals (P _28), the counter (CO ₀₎ of FIG. 4 through a line _{l 3, (CO 1),} (CO 2), (C
O ₃ ), T flip-flops (TF ₀ ) and (TE ₅ ) are released from the reset state. Next, the microcomputer (MC ₁ ) performs serial data input / output operation (hereinafter referred to as SIO), and the pin (SICK ₁ )
The eight serial clocks SICK are output from the counters, and the counters (CO ₀ ) and (CO ₂ ) count these clocks via the inverters (IN ₀ ) and (IN ₁ ). And the decorator (DE
₀ ) and (DE ₂ ) are pins (d ₀ ) to (d ₇ ) depending on the count value.
Sequentially set to "High", and circuits (AG ₀ ) to (AG ₇ ),
(AG ₁₀ ) to (AG ₁₇ ) are activated, and ROM (RO ₀ ) and (RO
The data from ₁ ) is sequentially output in serial from the lower bit through OR circuits (OG ₀ ) and (OG ₂ ). The Q output of the T flip-flops (TE ₀ ) and (TF ₅ ) is at the terminal (b ₂ ) at the rising edge of the eighth clock (falling edge of the inverter output).
Goes to "Low" and goes to "High", and goes to "Low" at the rising edge of the first clock of the next SIO. This Q
The counter (CO ₁ ) counts the falling edge of the output.

Table 1 shows the counter (CO ₃ ), decoder (DE ₃ ), RO in the lens (LE) when the interchangeable lens is a zoom lens.
The relationship between the address of M (RO ₁ ) and data, Table 2 shows the counter (CO ₁ ) and the decoder (DE) in the converter (COV).
₁ ) Indicates the interrelationship between the ROM (RO ₀ ) address, ROM (RO ₀ ) data, and the data output from the converter.

Table 3 shows the relationship between the address and data corresponding to Table 1 when the interchangeable lens mounted on the camera is a fixed focal length lens.

In these tables, all the check data are common to the interchangeable lens, and are used to check whether or not the interchangeable lens compatible with the system of this embodiment is properly attached to the camera body. Avo is the maximum aperture value (smallest aperture value) at the shortest focal length when the interchangeable lens used is a zoom lens whose aperture value changes according to the change in focal length. ,
Alternatively, a zoom lens has a fixed open aperture value if the aperture value does not change depending on the focal length. Avmax is the maximum aperture value, which is the maximum aperture value at the shortest focal length or the fixed maximum aperture value as in the case of the maximum aperture value. When the above three data are passed through the converter, the AND circuit (AN
₂ ) and the OR circuit (OR ₁ ), so it is sent to the camera as it is. In Tables 1 to 3, addresses and data represent ROM addresses and data, and output data represent converter data.

AFAvo is an open aperture value for automatic focus adjustment and detection. In the case of a fixed focus lens or a zoom lens whose aperture value does not change, the same data as the open aperture value is output. Further, in a zoom lens with a variable aperture value, data of the maximum aperture value (maximum maximum aperture value) at the longest focal length is output. This data is the serial addition circuit (ARC) of the converter (COV), and the data from the converter ROM (RO ₀ ) is 80H +
It is added with dAvc and output. Here, dAvc indicates the amount of change in the aperture value by mounting the converter (COV), and 80H indicates that the converter (COV) is mounted by setting "1" in the most significant bit of 1-byte data. It becomes a signal indicating that.

Next, 00H from the lens ROM (RO ₁ ), converter (COV)
The vignetting data of Avoc is output from the ROM (RO ₀ ).
The vignetting data indicates the limit aperture value at which the light flux incident on the camera body when the converter (COV) is mounted between the interchangeable lens and the camera body is vignetted by the converter. Therefore, when the converter is used, both vignetting data is added and the vignetting data Avoc is sent to the camera body.
To enter. If there is no converter, the data 00H from the lens is directly input to the camera circuit. Next, from the lens ROM (RO ₁ ), the conversion coefficient (kL) defined on the lens side among the conversion coefficients that converts the defocus amount calculated by the AF microcomputer (MC 2) into the rotation speed of the focus adjustment AF motor. Data is output. Here, the defocus amount is an amount indicating how much the image forming position by the lens of the portion of the subject to be focused is deviated from the planned focal plane, and is detected by the focus detection device in the camera body. To be done. The drive amount of the AF motor (automatic focus adjustment motor) required to drive the optical system for focus adjustment of the interchangeable lens varies depending on the interchangeable lens so that the defocus amount becomes zero. The coefficient for calculating the drive amount of the AF motor is called a conversion coefficient.
In the case of a zoom lens, the data of the conversion coefficient kL changes according to the focal length, so data corresponding to the address is output from the zoom code plate (FCP). In the converter, this data and the exchange coefficient kC by the converter from the ROM (RO ₀ ) are added and sent to the camera. This data is divided into a significant number part and an exponent part, and the data corresponding to each part is added in the converter. And this data is the actual value K in the AF microcomputer (MC ₂ ).
After being converted into L, the conversion coefficient KB and KL × KB in the camera body are calculated to calculate the conversion coefficient K of the entire system.

Next, the set or fixed focal length data fv (if the interchangeable lens is a zoom lens, the set focal length data, if it is a fixed focus lens, the fixed focal length data) is output, and is output in the converter (COV). COV) focal length change fvc data is added and sent to the camera body. Next, the lens outputs the data dAv of the difference between the aperture value at the shortest focal length and the aperture value at the set focal length (in the case of a zoom lens). In the converter, attach the converter to this data. The change in aperture value due to is added to dAvc and input to the camera body. In the camera body, Avo + dAv + dAvc is the open aperture value of the shooting optical system,
The minimum aperture value is Avmax + dAv + dAvc. If the converter (COV) is not attached, dAvc = 0, and if the zoom lens does not change the aperture value, dAv = 0.

Returning to the flowchart of FIG. 2, when the input of the lens data is completed, the photometric switch (S ₁ ) is pressed in step # 4.
If the photometric switch (S ₁ ) is closed, the process proceeds to step # 6, and if it is open, the process proceeds to step # 5. # The fifth step, by determining the input level of the terminal (P _23), if AF to determine (automatic focusing) mode or FA (automatic focus detection) mode, FA mode if # 6, AF mode # Go to 12 steps. This FA / AF discrimination is performed by switches (TSS), (ASS), (ISS), (MOSS), (UPS), (DO) other than the photometric switch (S ₁ ).
This is because when S) is closed and the control microcomputer (MC ₁ ) starts to operate, FA mode operation is performed and AF mode operation is not performed.

In step # 6, it is determined whether or not the check data is input from the lens. If the check data is not input, the lens is not mounted, so the AF or FA operation is not performed, and the process proceeds to step # 12. If the check data has been entered, move to step # 7 and AFAvo
Alternatively, AFAvo + dAvc is the defocus amount detection limit aperture value Avl for AF or FA (the limit aperture value at which a uniform light amount can be uniformly incident on the focus detection light-receiving part, for example, F5.6 (Av =
It is determined whether or not it is on the open side of 5), and since the defocus amount cannot be detected on the small aperture side, the AF and FA operations are not started and the process proceeds to step # 12. In the case of a zoom lens whose aperture value changes depending on the focal length, the reason why the maximum aperture value for AFAvo (the maximum aperture value at the longest focal length) is set is that the focal length varies from short focus to long focus. In order to prevent sudden stop of the AF or FA operation that was being performed because the open aperture value exceeded the limit aperture value and AF or FA became impossible while changing to In a zoom lens where a phenomenon occurs, AF and FA operations are prohibited from the beginning.

In the step of # 8, it is determined whether the lens of the terminal (P ₂₀ ) is “High” or “low”, that is, whether or not the operation of the AF microcomputer (MC ₂ ) is started. to step by sending an interrupt signal to the interrupt terminal (it ₁₎ the absence if the terminal (P ₂₀₎ deactivation AF microcomputer to Low to initiate (MC _2), the operation of the AF microcomputer (MC ₂₎ Let it start. Then A
F Data request D from microcomputer (MC ₂ ) to pin (P ₂₆ ).
Waits for TRQ to be input, and when it is input, the operation of subroutine I is performed.

In the subroutine I, desired data is serially transferred to the AF microcomputer (MC ₂ ) in response to the data request. First, a transform coefficient kL terminals (P ₂₅₎ as "High" SI
Set to the O register IOR and perform SIO operation. Then AFA
Register I for data with or without vo and converter (80H)
Set to OR to perform SIO operation. Next, it is determined whether or not the flag CDEF indicating that the calculation of the exposure control value is completed is set. If it is set, the exposure control value is calculated. SIO operation is performed by setting time Tvc and register IOR. On the other hand, when the flag CDEF is reset, the calculation of the exposure control value has not been completed, so AFAvo and Tv = 6 (1/60 sec)
Set and in the register IOR to perform SIO operation. After performing the SIO operation, return the pin (P25) to "Low".

In step # 12, Sv switch (ISS) and UP switch (U
ISO data is set according to the state of the PS) and DOWN switch (DOS), and in step # 20, it is determined whether or not the release switch (S ₂ ) is closed. If the release switch (S ₂ ) is closed, subroutine _{2 in} Fig. 3
Perform the operation of. On the other hand, if the release switch (S ₂ ) is open, in step # 21, the photometric output LMA input from the photometric circuit (LMC) in Fig. 1 to the analog input terminal (ANI).
N is AD converted based on the reference voltage VRAN input to the reference voltage input terminal (VRI) from the reference voltage source provided in the photometric circuit (LMC). Then, it is judged whether or not the data request signal is inputted from the AF microcomputer, and if it is inputted, the operation of the subroutine I is followed by the step of # 24, and if not inputted, the step immediately goes to the step of # 24.

In step # 24, the mode is set according to the states of the mode switch (MOSS), UP switch (UPS) and DOWN switch (DOS), and the process proceeds to the step corresponding to the contents of the mode register MOR. When the content of the mode register MOR is "0" and it is in the P mode, the operation in the P mode is performed in the step of # 29 and the process proceeds to the step of # 38. Next, the mode register MO
If the content of R is "2" and it is in A mode, Av in step 33.
The aperture value is set according to the states of the switch (ASS), UP switch (UPS), and DOWN switch (DOS), and the exposure calculation for the A mode is performed in step # 35 through step # 34. Move to step # 38. When the content of the mode register MOR is "3" and it is in S mode, in step # 31, Tv switch (TSS), UP switch (UPS), DO
The exposure time is set according to the state of the WN switch (DOS), the S mode is calculated in step # 37 via step # 32, and the process proceeds to step # 38. When the contents of the mode register MOR is 1 and the mode is M, the exposure time is set in step # 31 and the aperture value is set in step # 33.
In step # 36, the M mode calculation is performed and the process proceeds to step # 38.

Data Sv, Tvs, A in steps # 12, # 31, # 33 described above
For the setting of vs, first, Sv switch (ISS), Tv switch (TS
S), Av switch (ASS) and UP switch (UPS) or DOWN switch (DOS) is discriminated whether it is closed, and UP
If the switch (UPS) is closed, Sv setting is 1/3, Av
1/2 for setting, 1 for Tv setting, DOWN switch (DO
S) is closed, 1 / each for Sv, Av, Tv
Subtract 3,1 / 2,1. Then, it is determined whether each data exceeds the limit value, and if not, the data is left as it is, and if it exceeds, the limit value is set. In addition, these data changes can be made by UP switch (UPS) or D
If the OWN switch (DOS) remains closed, it will not be changed once it is changed, and once it is opened and closed again, the next change will be made. Also, when setting the mode, the mode switch (MOSS) and UP switch (UPS)
When is closed, 1 is added to the contents of the register MOR, and when a carry occurs, the contents of the register MOR becomes "0". That is, the mode of P → M → A → S is repeated. When the mode switch (MOSS) and the DOWN switch (DOS) are closed, 1 is subtracted from the contents of the register MOR, and the contents become "3" when a borrow comes out. That is, P ← M ← A ← S is repeated. In addition, even when switching the mode, the next mode switching is not performed unless the UP switch or the DOWN switch is opened once.

In step # 38, since the exposure control value has been calculated in the above steps, the flag CDEF is set and it is determined whether or not the release switch is ON. If it is ON, the process proceeds to subroutine II in FIG. 3, and if it is OFF, the display data is sent to the display unit (DSP), and the process proceeds to step # 42. Feed how this data is set to the terminal a (P ₂₇₎ "Low", may be performed an operation of SIO to set the display data in the register IOR.
In the step of # 42, it is determined whether the terminal ( _P37 ) is still "Low", and if it is "Low", the operation from # 2 is repeated. On the other hand, if the terminal ( _P37 ) is "High", it means that the switch has been opened, and the process will move to step # 43.
Determine whether the reset switch (S ₄ ) is ON and turn it ON (WE
If it is connected to the terminal), determine whether it is AF mode or FA mode. Then, in FA mode, it is possible to interrupt the terminal (it) and return to step # 3. On the other hand, in AF mode, the terminal (P
₂₁ ) is set to "Low" and the AF microcomputer operation stop signal AFSTP is sent, and the AF microcomputer waits for the AF end signal AFEN to be input. When AFEN signal is input, the terminal (P ₂₀₎ and (P ₂₁₎ and "High", reset switch (S ₄₎ to determine whether ON. And the reset switch (S ₄ ) is ON
If so, the process returns from step # 49 to step # 3. That is, switches (TSS), (ASS), (ISS), (MOSS),
(UPS), the (DOS) and the reset switch even all the terminal becomes OFF (P ₃₇₎ becomes "High" of (S1) (S ₄₎
If it is ON, the above-mentioned data reading, metering, and calculation display operations are repeated until the counter is interrupted. At this time, the operation of the AF microcomputer (MC ₂ ) also continues in FA mode, and in AF mode the terminal (P ₃₇ ) When it becomes "High", the operation of the AF microcomputer (MC ₂ ) is stopped.

If the reset switch (S ₄ ) is turned off when it is determined that the terminal (P ₃₇ ) is “High”, the AF microcomputer operation will start immediately regardless of whether AF mode or FA mode is selected. , Disable the counter interrupt in step # 51, enable the interrupt to the terminal (it), and wait for the AF microcomputer to input the signal STPOK to enable the operation stop.
When this signal is input, the flag CDEF is reset, the output of the reference clock STCL is prohibited, the transistor (BT ₀ ) is turned off, and the operation of the control microcomputer is stopped.

When it is determined that the terminal (P ₃₇ ) is High, and the reset switch (S ₄ ) is ON, the counter interrupts after a certain period of time (for example, 5 seconds), and the operation from step # 120 is performed. . In this case, if in FA mode, AF
Since the operation of the microcomputer (MC ₂ ) is continued, the operation of the AF microcomputer (MC ₂ ) is stopped and the process proceeds to step # 124. On the other hand, in the AF mode, the operation of the AF microcomputer (MC ₂ ) has already been stopped, so the process immediately moves to step # 124. Then, the counter interrupt is disabled, the interrupt terminal (it) is enabled, the AF stop enable signal STPOK signal is input, the reference clock STCL output is stopped, and the transistor (BT ₀ ) is turned off. Then, the flag CDEF is reset to stop the operation.

Next, the subroutine II will be described. In step # 80, it is determined whether or not the flag CDEF is set. In the reset state, the calculation of the exposure control value has not been completed, so the process returns to the main routine. If the flag CDEF is set and the exposure control value calculation is completed, the process moves to step # 81, the signal INREL indicating that the exposure control operation is in progress is output, and the AF microcomputer outputs A.
F Wait for the end signal AFEN signal to be input. And signal A
When FEN is input, it shifts to the actual exposure control operation. Table 4
Shows the relationship between the output of the terminals (P ₄₁ ), (P ₄₂ ), (P ₄₃ ), the output of the decoder driver (DEDR), the magnet that operates, and the operation of the camera.

In the exposure control operation, first, the release operation is performed to start the narrowing operation, and the time of τ ₀ is counted. At this time, a pulse is input from the aperture pulse output means (APC) to the internal event counter APCO via the terminal (CLI ₁ ) in conjunction with the aperture reduction operation, and the aperture stage number data Avc-Avo preset in this counter is output. Subtract one by one. Then, when the content of the counter APCO becomes "0", an interrupt occurs, the narrowing stop operation is performed in step # 88, and the process returns to this subroutine II. On the other hand, in Subretin II, when the counting of time τ ₀ ends, the mirror
The UP operation is performed and the time of τ ₁ is counted. Here, the narrowing operation is surely stopped during the time of τ ₀ + τ ₁ . Then, after the lapse of time T ₁ , the mirror UP is completed and the front curtain starts traveling. Then, after the time of 2 ^{- Tvc} elapses, the trailing curtain starts running and waits for the reset switch (S ₄ ) to turn off. When the reset switch (S ₄ ) is turned off, the signal INREL indicating that the exposure control is being performed is eliminated, the flag CDEF is reset, and the process returns to step # 42 of the main routine.

In FIG. 1, (MLMC) is a CCD which is composed of at least two sets of light receiving sections which receive the light transmitted through the taking lens (LE) and split by a known light splitting optical system. The interface circuit (INF) outputs a “High” pulse to the terminal (φR) when the terminal (P ₂ ) of the AF microcomputer (MC ₂ ) becomes “Low” to bring the charge storage section of the CCD to a predetermined voltage. . Then, when this pulse becomes "Low", the accumulation of charges according to the amount of light received by the light receiving element in the charge accumulating unit starts and the charge accumulation in the light receiving amount monitor unit of the CCD starts. Then, the interface circuit (INF) compares the monitor output AMO from the light receiving amount monitor of the CCD with the reference level, and when the monitor output reaches the reference level, the terminal (φT)
Output a transfer pulse to. Then, in the CCD, the charges accumulated in the charge accumulation unit are transferred to the transfer gate (analog shift register), and the light reception of each light receiving unit is performed based on the transfer pulse from the terminals (φ ₁ ) and (φ ₂ ) of the interface circuit. Signal ANO of the accumulated charge corresponding to the amount
It is output sequentially from O). Further, the interface circuit terminates the charge accumulation and outputs a transfer pulse to the terminal (φT), which is a signal indicating that the charge accumulation operation is completed.
Transmit INEN to AF microcomputer (MC ₂ ).

The interface circuit (INF) sequentially performs analog-to-digital conversion on the next input analog signal ANO, and the timing of inputting the analog-to-digital conversion data to the AF microcomputer (MC ₂ ) each time AD conversion is completed. outputs a pulse signal ADEN of indicating "Low", and inputs the a-D converter data bus input port of the AF microcomputer (MC ₂₎ through (ADD) (D _0). If the monitor output (AMO) does not reach the reference level when the accumulation time exceeds a certain time, the AF microcomputer (MC ₂ ) outputs a "Low" signal to forcibly stop the CCD charge accumulation operation. Outputs pulse INSTR and forcibly stops CCD accumulation operation. Then, the interface circuit amplifies the input signal ANO according to the level of the monitor output (AMO) when the integration is stopped in response to the stop of the accumulation operation, performs A-D conversion, and outputs the AF microcomputer (MC ₂ ).

(MCC) is a motor (MO) control circuit. First, the rotation of the motor (MO) is transmitted to a driven member in the converter via a transmission member (not shown), and further transmitted to a driven member in the interchangeable lens (LE) via the transmission member of the converter. Focusing of the optical system of the interchangeable lens (LE) is performed. Further, the rotation of the motor (MO) is transmitted to the encoder (ENCC), and a pulse corresponding to the rotation of the motor (MO) is output from the encoder. This pulse is input to the event counter in the AF microcomputer (MC ₂ ) via the terminal (CLI ₀ ), and the data of the planned rotation speed set in this event counter is subtracted according to the pulse. When the content of the event counter becomes "0", the event counter is interrupted. At this time, since the focusing optical system in the interchangeable lens has moved by the predetermined amount, the rotation of the motor (MO) is stopped or the high speed is switched to the low speed. Motor control circuit (MC
C) rotates the motor (MO) clockwise when the terminal (P ₄ ) of the AF microcomputer (MC ₂ ) becomes "Low", and rotates it counterclockwise when the terminal (P ₅ ) becomes "Low". P ₄ ) and (P ₅ ) are “Hig
The motor (MO) stops rotating when it reaches h ".
Motor (MO) is when terminal AF microcomputer (MC2) (P ₆₎ is "High" rotating at high speed, the terminal (P ₆₎ is "Lo
When w ", it is controlled to rotate at low speed.

The light emitting diode (RFL) is provided for rear pin display, the light emitting diode (IFL) is provided for focus display, and the light emitting diode (FEL) is provided for front pin display. Terminal (P7),
It is driven when (P8) and (P9) become "Low".
Also, (FLS) is a focus lock switch, and when this switch is closed, the motor (MO) stops and the photographic optical system is fixed at its focus position. When the switch (AMS) is connected to the terminal (AF), it is in AF mode, and when it is connected to the terminal (FA), it is in FA mode in which only the focus display is performed. The switch (SNS) is a single mode that operates the AF microcomputer (MC ₂ ) independently (for example, by incorporating the AF circuit in the interchangeable lens to make an AF lens, or when using a fixed lens type camera whose shooting lens is not interchangeable, It is connected to the terminal (SIN) when the circuit for built-in is built in, and also in the operation mode of the AF microcomputer (MC ₂ ) when checking the operation of the AF microcomputer. On the other hand, the first AF circuit
As shown in the figure, when the camera is used with the interchangeable lens attached, the switch (SNS) is connected to the AF microcomputer (MC ₂ ) via the terminal (NOM), and the AF microcomputer (MC ₂ ) is in normal mode. Do the operation in. Both the single-mode and normal-mode operation programs described above are prepared in the AF microcomputer (MC ₂ ), and one program is used depending on the state of the switch (SNS). This switch (SNS) is set to ON or OFF at the time of production, and the photographer cannot operate it.

Fig. 5 shows a circuit diagram when the circuit parts required for AF such as the above-mentioned AF microcomputer (MC ₂ ) are mounted in an interchangeable lens with an AF function. In this case, the switch (SNS) is connected to the terminal (SIN). The terminal _{(P 7), (P 9} ) ~ (P 11), (P 13)
The conversion coefficient data specific to this lens is input to (P ₁₆ ). That is, the data from the zoom code plate (FCP) corresponding to the focal length set is converted into the data of the transform coefficients via a decoder (DCC), the terminal _{(P 7), (P 9} ) ~ (P 11 ), is input to the _{(P 13) ~ (P 16} ). Furthermore, the display of the in-focus state, when in focus,
The buzzer (BZ) operates only for a certain period of time via the control circuit (SOC), and no visual display (LED) is provided. Furthermore, the operation of the AF microcomputer (MC ₂ ) starts immediately after power supply starts. Therefore, the function of the interrupt terminal (it ₁ ) is unnecessary and it is connected to the power supply via the pull-up resistor.
Also, since the AF operation stops when the power supply is stopped or the exposure control of the camera body starts, the interrupt terminal (it ₂ ) is not required and it is connected to the power supply. In addition, as described above, the lens (LE) data is temporarily transferred to the control microcomputer (M
Since it is not necessary to read serial data after passing through C ₁ ), the serial input terminal (SIIN ₀ ) should be connected to the clock input terminal (SIC
K ₀ ) is also connected to the power supply.

Next, the operation of the AF microcomputer (MC ₂ ) will be described with reference to the flowcharts shown in FIGS. AF microcomputer (MC ₂ ) is No.1 by power-on reset (power ON)
The operation starts from step. First of all, in the No. 1 step, all flags are cleared. Here, if each flag is set to be "0" in the initial setting, the initialization can be easily performed in this way. Next is No.2
Output data (CCD
Dark output) is set to "0". Next, in the step of No.3, read the signal from the single / normal switch (SNS) and if this is "High", proceed to No.9 as the single lens mode (single).
Initialize the input / output port when using No.9 and No.10 as single mode. Here, the input / output ports are all set to the input mode by the power-on reset when the power is turned on, and only the port used as the output mode needs to be set. Then, in the steps of No. 11 and No. 12, only the interrupt to the terminal (it ₃ ) is permitted and the step No. 36
Move to the integration routine of. Here, in the case of the single mode, the activation is performed by turning on / off the power switch. The only focusing mode is one-shot automatic focus adjustment (the lens position is fixed during AF operation once in focus). On the other hand, if it is determined to be "Low" in the step of No.3, the camera (normal) mode is set and the process proceeds to the step of No.4. Initialize the I / O port in steps No.4, No.5 and No.6, and interrupt the terminal (it ₁ ), terminal (it ₂ ) and terminal (it ₃ ) in steps No.7 and 8. After permitting, enter stop mode. Here, the stop mode is one function of the microcomputer itself and is a power saving mode in which the clock is stopped and the memory is held. Using this mode prevents you from consuming too much power. Further, the AF microcomputer (MC2) is configured to come out of the stop mode by being reset or receiving an interrupt. Although not shown in the flowchart, the control microcomputer also performs the power-on reset operation at the same time, and when it stops the operation, it outputs the AFSTP signal for stopping the AF operation.
When the AF microcomputer receives this signal, the AF microcomputer determines whether or not the operation can be stopped, and outputs the "Low" STPOK signal indicating that the operation can be stopped. Then, the control microcomputer stops the output of the reference clock STCL, and both microcomputers stop operating.

In normal mode, AF from the control microcomputer (MC ₁ ) side
When trying to start the microcomputer (MC ₂ ),
"come to output a signal AFSTA in. In this way .No.14 step proceeds to step from the AF microcomputer takes interrupt pin (it ₁₎ No.14, terminals (P _13)" w Hig
Set it to "h" and inform the control microcomputer (MC1) that the reference clock output to the AF microcomputer should not be stopped.
In the "Low" terminals (P ₁₄₎ in step informs the control microcomputer to the AF microcomputer begins to move. In the steps from No. 16 to No. 20, only the necessary interrupts to the pin (it ₂ ) and pin (it ₃ ) are permitted, and other interrupts are prohibited. In the No. 21 step, the after release flag AFRF indicating whether or not the release operation is performed is determined,
This determines whether the interrupt routine to this pin (it ₁ ) is an interrupt after release. Flag AFRF
If is “1”, there is an interrupt after release and the process proceeds to No. 22 and subsequent steps, which will be described later. No.2
If the flag AFRF = 0 is determined in step 1, No.
Go to step 27. From No.27, it is the first serial communication step to transfer data in series with the control microcomputer.

In the step No. 27, "0" is set to the serial data counter (k). Here, the number of data is “4”, and one data is 8 bits. Next, enable the serial communication interrupt in step No.29. Here, the serial interrupt is configured to issue an interrupt request when eight serial clocks SICK are input to the terminal (SICK ₀ ) and 8-bit serial data is input to the serial data register.
Next, at the step of No.30, the terminal (P ₁₆ ) is set to "Low", and a serial communication request DTRQ is issued to the control microcomputer (MC ₁ ). In response to this request, the control microcomputer (MC ₁ ) outputs a serial clock and data. At this time, the control microcomputer (MC ₁ ) outputs a “High” signal to the terminal (P ₂₅ ). This is a serial communication line display circuit (DSP)
This is because it is also used for communication with other parts such as a lens ROM and the like, so that a selection signal for each circuit is required so that data does not cause interference. Therefore, the control microcomputer (MC ₁ ) is AR
When performing serial communication with the microcomputer (MC ₂ ), set the pin (P ₂₅ ) to “High” and select the AF microcomputer (MC ₂ ). In the AF microcomputer (MC ₂ ), the above selection signal CSAF is "Low".
If the gate of the serial clock SICK is closed at the time of and the gate of the serial clock is opened only when the selection signal CSAF is "High", the communication data to other circuits will not be received.

As a request for serial communication, that all of the data by an interrupt After outputs a signal "Low" to the terminal (P ₁₆₎ is input wait step of No.31. Serial clock SIC
When eight K's are input, a serial interrupt occurs and N in Fig. 6 is entered.
Move in steps of o.225. In the step of No.225, the data input to the serial register is transferred to the register SDR (k), and in the step of No.226, the next register SDR (k) +1.
To set. To the terminal (P ₁₆₎ at No.227 of step "High"
Is output and the process returns to the routine of FIG. When this interrupt is entered four times, all the data is input and the value of the serial data counter (k) becomes "4". No.3 by this
Proceed from step 1 to step No. 32 to disable the serial interrupt and finish the serial communication. The No. 33 step receives the signal from the AF / FA selector switch (AMS), and if that signal is "High", it is AF mode and the focus mode flag FMF is "0". If it is "Low", it is FA mode. Set the flag FMF to "1". Then, the process proceeds to the integration routine after step No.36. In single mode, serial communication is not required, so proceed from step No. 12 to step No. 36.

In the step of No. 36, the low light flag LLF is cleared. This is set when the subject has low brightness and the CCD accumulation time reaches a predetermined maximum time. Next No.3
Set the event counter value to n ₁ in step 7.
This event counter is a subtraction counter that subtracts and counts the input pulse to the terminal (CLI ₀ ) at its falling edge. A pulse from the encoder circuit (ENCC) that monitors the rotation amount of the motor (MO) is input to this terminal (CLI ₀ ). In addition, the counter value n ₁ is used for moving amount correction in defocus measurement while the motor is being driven, and is not used in measurement when the motor (MO) is stopped. N
Go to step o.38 to reset the built-in timer,
Enable the timer interrupt in step No.39. Then, in the step of No. 40, the "Low" signal is output to the line terminal (P ₁ ) for a certain period of time and the interface circuit (IN
Let F) start CCD integration. Start the timer at step No.41 and start counting the integration time. In step No. 42, it is determined whether or not the integration end signal is input from the interface circuit (INF). This signal INEN becomes “Low” when the CCD charge storage amount reaches an appropriate value, indicating the end of integration. Therefore the signal IN
When EN is judged to be “Low”, the integration is completed and the process goes to No.49 through No.48. Signal INEN is "High"
In the case of, it is checked in step No.43 whether or not the timer has reached time t ₁ . This time t ₁ corresponds to the end detection time interval. If no pulse from the encoder circuit arrives during this time t ₁ , it is judged that the lens has reached the end, but the check is done in the end detection subroutine (No. 45) in step No. 45. Call (Fig. 11). In the step of No.43, the value of the timer is the time t ₁
The value of the timer proceeds to step No.44 is not equal to it is checked whether the reached maximum integration time t _2, when it reaches its time t ₂ proceeds to step Step No.46. If the timer value has not reached time t ₂ , No. 42
Return to step and repeat the above steps. In addition,
If the integration is completed before the timer counts the time t ₀ (t ₀ << t ₂ ), the subject has high brightness, and at this time, the flag HLF is set and the process proceeds to step No. 48.

If the longest integration time t ₂ is reached, the terminal (P ₂ ) is set to “Lo
Output "w" for a certain period of time and forcibly terminate the integration. No.47
In the step of, the low light flag LLF is set, the highlight flag HLF is reset, and the process proceeds to step No.49.
Disable the timer interrupt in step No.49, and stop the timer in step No.50. In the No. 51 step, set the counter value to n ₂ as in the No. 37 step. A value obtained by A / D converting the CCD output by the interface circuit after a fixed time from the end of integration is output as ADD. In step No.52, this ADD signal is sequentially fetched from the input port (D ₀ ) and stored in the memory at the falling edge of the timing signal ADEN to the terminal (P ₃ ).

When the data acquisition is completed, check the terminal (P ₁₂ ) and if it is "Low" in normal mode, proceed to No.54 step, and if it is "High" in single mode, proceed to No.55 step. In step No. 54, the value obtained by subtracting the dark output data corresponding to each CCD data is used as the dark output correction data.

Then, in step No. 56, the focus lock check subroutine of FIG. 6 is called. The focus lock check subroutine starts from step No.229. In the step of No.229, the focus mode is checked by the flag FMF, and if the focus mode is FA mode, the focus lock switch (FLS) is not checked and the process returns. In AF mode, proceed to No.230 and check the signal of the focus lock switch (FLS). When the signal from the switch (FLS) is "High", that is, when the focus is not locked, the process proceeds to No.236. When the signal of the switch (FLS) is "Low", it means that the focus is locked, and the process proceeds to No.231 step. In the step of No. 231, the flag FLF of the focus lock is checked and FLF is checked.
When = 1, the process does not proceed to No. 232 and subsequent steps and returns. If FLF = 0, go to step No. 232 and issue a stop signal to the motor (MO). Next, the motor flag MOF is cleared, the counter interrupt is prohibited, and the focus lock flag FLF is set. No.36 after performing the above processing
Return to step. When the focus lock switch (FLS) is "High", the focus lock flag FLF is checked in step No. 236, and when FLF = 0, the routine so far returns because it is not in the focus lock state. When FLF = 1, the focus lock state has been released, and the focus lock flag FLF is cleared in step No.237. Then it is determined whether or not a low contrast state by low contrast flag LCF ₀ in step Nanba238, low contrast flag LCF ₀ For low contrast state, LCF _1, LCF _2, L
Clear all CF ₃ and return to the initial state. Next No.24
At step 0, the display is erased and the process returns to step No.36. If it is determined in step No.238 that the contrast is not low, skip step No.239.
The display is erased at step No.240 and the process returns to step No.36.

Now, return to the main routine and proceed to step No. 57 to prepare for serial communication again. No.57 to No.59
The steps of No. 27 to No. 30 are the same. The request for serial communication is made here to capture variable data. The serial communication process is No. 6 below.
Handled by an interrupt during the calculation in step 0.
On the other hand, the process proceeds to step No.55 For single mode terminals (P ₁₂₎ is "High" in step No.53, terminal from the decoder circuit of FIG. 5 _{(DCC) (P 7),} (P 9 ) ~
Use (P ₁₁ ) and (P ₁₃ ) to (P ₁₆ ) to load the conversion coefficient K data and store it in the memory. And No.60
Go to step. In step No. 60, a predetermined calculation is performed based on the CCD data to calculate the defocus amount Δε and the defocus direction. In the step of No. 61, serial interrupt is prohibited, and it moves to the contrast judgment of No. 62.

If contrast is determined in step No. 62, N
o.63 and subsequent steps, if the contrast is normal,
Proceed to steps after No.93. If it is determined that the contrast is low, the flag No. FLF is used to check whether or not the focus lock state is set in the No. 63 step. If the focus lock state is set, the process proceeds to the No. 82 step. In steps No.82 to No.85, the low contrast flag LCF ₀ is set and the low contrast is displayed (RFL and LFL blinking, etc.), and the procedure returns to step No.36 for remeasurement. If it is determined in step No. 63 that the focus state is not reached, then move to step No. 64 and check the focusing mode this time. If the focusing mode is FA mode, proceed to No. 82 and subsequent steps. In AF mode, the motor (M
O) is driving or stopped.

First, in the case of the stopped state, the process proceeds to No. 66, and it is determined whether or not the low contrast scan is possible by the low contrast flag LCF ₃ (low contrast scan prohibition flag). Here, if the flag LCF ₃ is set, it means that the scan is in a prohibited state, and the process proceeds to No. 82 and subsequent steps. When the flag LCF ₃ is clear, the low contrast scan is permitted, and the process proceeds to No. 67 and subsequent steps. In steps No.67 to No.69, low contrast display and low contrast flag LCF ₀ are set. Low contrast flag L in step No. 70
Set CF ₁ (Low contrast scan flag). Next, in the step of No. 71, it is checked whether or not the subject has low brightness by the low light flag (LLF).
Set ₂ (reverse scan flag) and proceed to step No.76. This is a process for performing a low-contrast scan only in the retracting direction when the luminance is low, and is for retracting the lens to the ∞ position when the lens cap is attached. If it is determined that the brightness is not low in step No.71, the process proceeds to step No.72 to clear the low contrast flag LCF ₂ . Next, in the step of No.74, if the defocus direction is the rear pin, No.75 clears the drive direction flag DDF, and if it is the front pin, set the drive direction flag DDF in step No.76 and set the next step. Continue to No. 77. In No.77 step outputs "High" to the terminal (P _6), setting the rotational speed of the motor (MO) quickly. Then, in the step of No.78, set the motor flag MOF and No.7.
In step 9, the motor (MO) is energized according to the driving direction flag DDF described above, the scan mode is entered, and N
Return to step o.36.

If it is determined that the motor is being driven in step No.65, it is determined in step No.86 whether the drive is a low contrast scan drive or a normal drive, and if it is a low contrast scan, the end detection is performed. Return to step No. 36 to continue the low contrast scan. When the contrast becomes low from the normal state, No.87
Proceed to the following steps, and first stop the motor (MO) and clear the motor flag MOF. Then, the low contrast flag LCF ₀ is set, the low contrast is displayed, and the process returns to step No. 36 for remeasurement.

If it is determined that the contrast is not low in step No. 62, the process proceeds to step No. 93. In the No. 93 step, check the focusing mode, and in the FA mode, move to the No. 97 step. Check the low contrast flag LCF ₀ at No.97 step, so far in the case were low contrast, clear the low contrast flag LCF _0, clear the low contrast display
Go to step after No.106. If the AF mode is determined in step No. 93, the process proceeds to step No. 94. No.
Low contrast scan disable flag in step 94
Set LCF ₃ . Therefore, once the normal contrast is obtained, the low contrast scan is prohibited thereafter. Next, in step No. 95, low contrast flag LCF
_{By 0,} it is checked whether or not the contrast is low up to this point. In step No. 101, the motor (M
Stop energizing to O). Next, in step No.102, the motor flag MOF is cleared, in step No.103, the low contrast flags LCF ₀ , LCF ₁ , and LCF ₂ are cleared, and in the normal mode, the low contrast display is erased, and then remeasurement is performed. Therefore, return to step No.36.

If it is determined in step No. 95 that the contrast is not low, proceed to No. 96, check the focus lock flag FLF, and if the focus is not locked, set N.
Go to steps after o.121. If it is in focus lock state, do not go to the normal routine in AF mode,
Proceed to the FA mode routine after No. 106. In step No. 106, the focus width ZFA in FA mode is set. The focus width ZFA in FA mode is variable according to the maximum aperture value AFAv ₀ for AF. Here, ZFA = (AFAv ₀ + α) × β is set.
Here, α is a bias, β is an appropriate coefficient, and ZFA is a unit of μm. Next, in step No. 108, it is determined whether the defocus amount Δε is within the focusing width ZFA. If the defocus amount Δε is within the focus width ZFA, No.
If it exceeds the focusing width ZFA, proceed to step 119.

The steps after No. 119 are the processes within the focus range.
"High" is output to the terminal (P ₁₄ ) with and the control microcomputer (MC
Notify 1) that the subject is in focus. And No.120
At the step, the LED (IFL) that indicates the focus is turned on and the procedure returns to step No.36 for re-measurement. The steps after No.111 are the processing when the focus width is out of focus. In the step of No.111, "Low" is output to the terminal (P ₁₄ ) and the control microcomputer (MC1) is out of focus. Notify that terminal (P ₃ ) is "High"
Is output to clear the focus display. In step No.113, the focusing mode is determined. In AF mode, No.1
Go to step 15. It is only in the focus lock state that this routine is reached in AF mode, and the defocus display is erased and the procedure returns to step No. 36 for remeasurement. F
When in step A, the defocus direction is determined when the step No. 114 is reached and the LED (RFL) is lit for the rear pin (step No. 116) and the LED (FFL) is lit for the front pin. Then (step No.117), return to step No.36 for re-measurement.

When the process proceeds from step No. 96 to step No. 121 in Fig. 9, it is first determined whether or not the converter (COV) is installed. Information on converter (COV) installation is No. 7
It is sent from the control microcomputer by serial communication in the step No.31 in the figure. If the converter (COV) is not installed, proceed to step No.122 to convert coefficient
Determine if KL is less than the limit value K ₁ . This limit value K ₁ is a limit conversion coefficient value that makes it difficult to stop within the region of the minimum value b of the focus width when the stopping accuracy of the motor (MO) is taken into consideration. If it is determined in step No.122 that the conversion coefficient KL is larger than the limit value K _1, No.124
Go to step No. 126 and set the minimum value b to the focus width ZFA in AF mode and go to step No. 126. If the conversion coefficient KL is smaller than the limit value K _{1 in} the step of No. 122, the process proceeds to the step of No. 123 and the focus width ZFA is set to a value obtained by multiplying the photographing aperture value by a. Here, the value of coefficient a is ZFA
The value of is larger than the minimum value b so that it falls within the depth of focus. If the focus width is widened in this way, the movement of the lens can be smoothed even in a region where the drive control of the motor (MO) is difficult. If it is determined that the converter is installed in step No.121, the process proceeds to step No.125 and the value obtained by multiplying the photographic aperture value by the bias component C and the coefficient a is set as the focusing width ZFA. Set.
This is because when the converter (COV) is installed, the drive control of the motor becomes more difficult than in the case of step No. 123, so the bias component C is added.

After setting the focusing width, the defocus amount and the focusing width are converted into the pulse count of the encoder (ENCC) in step No. 126. A value Δn ′ obtained by converting the defocus amount into a pulse count number is calculated by multiplying the defocus amount Δε by the conversion coefficient KL on the lens side and the conversion coefficient KB on the camera body side. Similarly, the value ZAFC obtained by converting the focus width ZFA into the pulse count number is calculated by multiplying the focus width ZFA by the conversion coefficients KL and KB on the lens side and the body side. The conversion coefficient sent from the control microcomputer is the data kL divided into the effective number part and the exponent part, so it is necessary to convert it to the actual conversion coefficient KL.

Then proceed to step No. 127 to set the motor flag (MOF)
Whether the motor is being driven is determined by. When the motor is stopped, the process proceeds to step No. 128, and the defocus pulse count number Δn 'is set to the drive pulse number Δn, and the process proceeds to step No. 135. If the motor is being driven in step No.127, proceed to step No.131 to check the end detection. If it is not the end, proceed to No. 132 step and encoder count value at the end of calculation n ₃
Read. Then, in step No.133, the movement amount correction amount Δn ″ = n ₁ −n ₃ − (n ₁ −n ₂ ) / 2 is calculated, and in step No. 134, the movement amount is corrected and a new defocus is performed. The count number Δn = Δn′−Δn ″ is calculated. In step No.135, it is determined whether the defocus count number Δn is within the focus width count number ZAFC. If Δn is greater than ZAFC, proceed to step No.149, where Δn is less than ZAFC. In the case of, the focus state is set and the process proceeds to step No. 136. In step No.136, the power to the motor (MO) is stopped and N
Clear the motor flag MOF in step o.137.
Then, in step No. 138, the new defocus count Δn is stored as the previous defocus amount ΔnL. The Next, in the case of checking the terminal (P ₁₂₎ proceeds to step of NO.139 terminal (P ₁₂₎ is "High" proceed to step of NO.145 be a single mode. NO.145 terminal at step (P ₈₎ to "Low" output focus buzzer (BZ) for a predetermined time (step No.146, No.147) which in one measurement of the case of single mode is turned on The operation is completed, and at the step of No.148, the state of waiting for an interrupt signal is entered.

If the terminal (P ₁₂ ) is determined to be "Low" in the step of No.139, it is in the normal mode and proceeds to the step of No.140 to set the focus flag AFIFF and at the same time clear the first-out flag FOF. Te next steps, outputs "High" to the terminal (P _14), informs the control microcomputer that the state of focusing completion (MC _1). No.142, No.143
In step returns to No.36 step for again turns on the focus display LED (IFL) by outputting only the "Low" to the terminal (P ₈₎ measurements.

If Δn is larger than ZAFC in step No.135, go to step No.149 and output "Low" to the terminal (P ₁₄ ) to confirm that the AF microcomputer is not in focus. To the control microcomputer (MC ₁ ). Next No.150
If the motor flag MOF is set in step, proceed to step No.155 and store n ₃ as the previous defocus count number ΔnL. If the motor flag MOF is cleared in the step of No.150, it is in the stopped state and proceeds to the step of No.151. Here, the setting of the near zone near the focusing width will be described. First of all, there are two types of widths for the near zone. One is the width Nzn for distinguishing when entering the near zone from outside the near zone, and the width for distinguishing after following the subject at low speed after entering the near zone. Nzw (Nzw> Nzn), and Nzw is j times (j> 1) the pulse count number ZAFC corresponding to the focus width. On the other hand, Nzn is variable according to the calculated rotation amount. First, there is the maximum amount of rotation N ₁ from when the motor (MO) rotates at the highest speed to when it is stopped by being braked. Then, there is a maximum rotation amount N _{2 of} the motor (MO) from the stopped state to the maximum speed. When the calculated rotation amount Δn is Δn> N ₁ + N ₂ = X ₁ , the near focus zone Nzn should be N ₁ . On the other hand, when Δn <N ₁ + N ₂ , when N ₁ is set as Nzn, the motor (MO) is braked before reaching the maximum speed, and after reaching a certain low speed early, the focus position is set at a low speed. Since it is driven up to, there is a problem that it takes a long time to reach the focus position. This becomes a problem especially when Δn takes a value close to N ₁ . Therefore, when the defocus count number Δn is larger than X _{1 in} the step of No. 151, the maximum value N ₁ is set as the width Nzn of the near zone. (X ₁ > N ₁ ) Conversely, if Δn is smaller than X _{1, the} defocus count number Δ
Let d (d <1) times n be Nzn. In step No.154, the focus zone takes j (j <1) times the count number ZAFC as the width Nzw of the near zone for subject tracking (Nz
n <Nzw). Then, the focus flag AFIFF is determined, and if the flag is set, the process proceeds to step No.156. If the focus flag AFIFF is cleared, the first-out flag FOF is determined.If the first-out flag FOF is set, proceed to step No. 156.If the first-out flag FOF is cleared, the previous time is determined. The defocus count Δn of this time is stored as the defocus count number ΔnL of. In the step of No.156, it is judged whether or not the highlight flag HLF is set, and if it is reset, the step No.1
The process from No. 57 to No. 160 is not performed, and the process proceeds to the step of No. 159 to store the current defocus count number Δn as the previous defocus count number ΔnL, and proceeds to the step of No. 164.

No.157 when the highlight flag HLF is set
Go to step and the previous defocus count number △ nL
And the current defocus count number Δn, that is, the defocus count change amount Δ ² n is calculated, and this change amount Δ
^{When 2} n is smaller than the fixed amount L _{1, the} process proceeds to step No. 159 as in the case where the flag HLF is reset. If the amount of change Δ ² n is larger than the fixed amount L ₁ , proceed to step No. 160 to determine the first-out flag FOF, and
If OF is not set, proceed to step No. 161 and output a stop signal to the motor (MO). And No.1
Clear motor flag MOF in step 62, No.16
Set the first out flag FOF in step 3 and return to step No. 36 for remeasurement. If the first out flag FOF is already set in step No. 160, proceed to step No. 164. This amount of change △ ² n
The process of obtaining and comparing with a constant amount L ₁ is performed in order to avoid a quick response when a large defocus amount is erroneously calculated while following the subject.

In step No.164, the first out flag FOF is cleared and the focus flag AFIFF is cleared.
Next, in the step of No.165, check the near zone flag NZF. If the near zone flag NZF is set, N
To the step of o.170, if the near zone flag NZF is not set, proceed to the step of No.166. in this way,
According to the near zone flag NZF,
This is because once the vehicle enters the near zone, the following mode is set to widen the range in which the motor (MO) is driven at low speed. Therefore, in step No.166, the defocus count number Δn is compared with the narrower near zone count number Nzn, and in step No.170, the defocus count number Δn is compared with the wider near zone count number Nzw. To do. N
If it is determined in step o.166 or No.170 that the defocus count number Δn is smaller than the near zone count number, go to step No.167 and set the near zone flag.
Set the NZF. Then, in the No. 168 step, the terminal (P
₆ ) Outputs "Low" to the motor control circuit (MCC) to control the motor (MO) at low speed. And No.1
Proceed to step 69 to load the defocus count number Δn into the counter, and proceed to step No.175. If it is determined that the defocus count number Δn is larger than the near zone count number in the No.166 or No.170 step,
Go to step No.171 to clear the near zone flag NZF. Next, in the step of No. 172, set the terminal (P ₆ ) to “Hig
Output "h" to the motor (MO) to the motor control circuit (MCC)
Is controlled at high speed, and in the step of No.173, the defocus count number Δn to the near zone count number Nzn
Load the value obtained by subtracting into the counter and proceed to step No.175. In FIG. 10, steps No. 175 to No. 182 are processing when the lens is at the end. In step No.175, check the end flag TEF and check the end flag TEF.
If is not set, the lens is not at the end position and proceeds to step No.183. If the end flag is set, the lens is at the end position and the process proceeds to step No.176. In the step of No. 176, the defocus direction is discriminated, and if it is the front pin, proceed to the step of No. 177, and if it is the rear pin, proceed to the step of No. 178, and both check the end position flag TPF. Here, the end position flag TPF indicates the closest end when set, and the infinity end when clear. N
If the end flag TPF is cleared in step o.177, the lens cannot be retracted any further because the front focus state is set at the end at infinity, and the process proceeds to step No.180. When the end position flag TPF is set, the closest pin is in the front pin state and the lens is retracted, so the process proceeds to step No. 179 to drive the motor (MO). If the end position flag TPF is set in the step of No.178, it is in the rear pin state at the closest end, and the lens cannot be extended any further, and the process proceeds to the step of No.180. If the end position flag TPF is cleared, the lens is in the rear focus state at the infinity end, and the lens will be extended, so proceed to step No.179. In steps No.180 to No.182, all the in-focus and out-of-focus indications are erased, and the procedure returns to step No.36 for remeasurement. No.179
In the step, first clear the termination flag TEF, and then
Check motor flag MOF in step 183. If the motor flag MOF is set, the motor is already being driven and the process returns to step No.36 for remeasurement.

If the motor flag MOF is cleared in step No.183, the motor is in a stopped state, and proceed to step No.184 to set the motor flag MOF. Next No.18
The defocus direction is discriminated in step 5, and if it is the front pin, go to the step No. 186, and if it is the rear pin, go to the step No. 188. In step No.186, drive direction flag DD
Set F and clear drive direction flag DDF in No.188. Then, the terminal (P ₄₎ is a step of No.187 "Low"
Is output, and in the step of No.189, “Low” is output to the terminal (P ₅ ) and the motor (MO) is driven in each direction.
Next, at step No.190, wait until the speed of the motor (MO) becomes almost constant and then return to step No.36.

The steps after No. 191 are it ₃ interrupt processing routines. The it ₃ interrupt is an interrupt indicating a release request from the control microcomputer (MC ₁ ). No when it ₃ interrupt is accepted.
Go to step 191. The No.191 step to determine the terminal (P _12), "High" output to focusing buzzer "High" to the terminal (P ₈₎ proceeds to step No.192 a single mode in the case of ( BZ) to OFF. Then the terminal in steps of _{No.193 (P 4) (P 5} ) stops the motor (MO) in the both "High" and motor flag in steps of No.194
Clear the MOF. In this state, INR in step No.195
Wait for the EL signal to go "High" and return to step No.148. No.191 of the terminal at step (P ₁₂₎ is "Lo
If it is "w", it is the normal mode, and proceed to step No.196 to set the after release flag AFRF.
At the step of o.197, a "Low" pulse is output from the terminal (P ₂ ) for a certain period of time to end the CCD integration. No. 198
In step, store the display status in memory and proceed to No. 199 to output “High” to terminals (P ₇ ), (P ₈ ), and (P ₉ ), respectively, and erase the display. Next, proceed to step No. 200, output "High" to the pin (P ₁₆ ) to release the serial data communication request QTRQ, and disable serial interrupt in No. 201.
Then, in the step of No.202, "High" is output to the terminal (P14) to inform the control microcomputer (MC1) that the release may be started. In the step of No.203, "High" is output to the terminal (P13). Is output. Then go to step No.204 to reset the built-in timer. Start the timer in the step of No.205 and wait until the timer counts the predetermined time T ₀ in the step of No.206. When the timer count reaches T ₀ , a “Low” pulse is output to the terminal (P ₁ ) for a certain period of time in step No. 207, and the interface circuit (IN
Let F) start CCD integration. At the time of release start, the shutter that blocks the light from the CCD sensor (MLMC) is closed, and the light does not reach the CCD sensor.
Therefore, the integration here accumulates charges corresponding to the dark output. Further, when the timer count reaches T ₁ in step No. 208, the process proceeds to step No. 209.
In step No. 209, it is determined whether or not the shooting Tv value is larger than the limit value TvL. If the shooting Tv value is larger than the limit value TvL, the motor (MO) is not stopped and driving is continued. However, since the counter interrupt is permitted, the counter interrupt is accepted and the motor is stopped when the driving has been completed. The counter interrupt routine will be described later. The limit value TvL is a limit value that does not affect the exposure even if the taking lens moves. N
If the shooting Tv value is smaller than the limit value TvL in step o.209, proceed to step No. 210 to turn off the drive signal to the motor (MO) and stop the motor (MO). In addition, after the motor (MO) actually stops rotating due to "High" of the drive signals RRT and LRT, the values of timers T0 and T1 are set so that the leading shutter curtain starts (# 91 in Fig. 3) in the camera. Is set. Then, in step No. 211, the motor flag MOF is cleared. Then proceed to step No. 212 and wait until the timer count reaches T ₂ . When the count of the timer reaches T ₂ , go to the step of No. 213 and output “Low” to the terminal (P ₂ ) for a certain period of time to terminate the integration of the dark output. The CCD data for the output is captured and stored in memory. The above processing is performed to enter the interrupt waiting state.

The it ₂ interrupt is an AF stop interrupt from the control microcomputer (MC ₁ ), and its processing routine starts from step No. 216 in FIG. When the it ₂ interrupt is accepted, the process proceeds to step No.216. In step No.216, the drive signal to the motor is turned off and the motor is stopped. Then the terminal in steps of _{No.217 (P 7), (P} 8), respectively (P ₉₎ "Hi
Outputs High "" to a terminal (P16) in .No.218 the step of erasing the output to display the "gh, terminal proceeds to step .No.219 releasing a request for serial data communication (P ₂₎ Then, "Low" is output for a certain period of time to end the CCD integration (INSTP), then proceed to step No. 220 and proceed to terminals (it ₁ ), (i
Disable interrupts other than t ₃ ) and output “High” to the terminal (P ₁₄ ) at the step of No.221 to notify the control microcomputer (MC ₁ ) that automatic focus adjustment is completed. And No.222
In the step, clear all the flags that need to be cleared. Go to No. 223 and go to the terminal (P ₁₃ ).
"Low" is output to the power saving mode.

The counter interrupt processing routine is step No. 2 in Fig. 11.
It starts from 41, the counter countdown progresses, and when it reaches “0”, a counter interrupt request is generated, and No. 241
The process moves to step. In step No. 241, the drive signal to the motor (MO) is temporarily turned off. Next, in the step of No.242, check the near zone flag NZF and check the flag N.
If ZF is clear, proceed to step No. 243 to switch the motor rotation speed from high speed to low speed. Outputs "Low" in the No.243 terminal (P _6), causes the motor control circuit (MCC) to control the motor (MO) at a low speed. When the process proceeds to step No.244, the near zone count number Nzn is loaded to the counter, and the near zone flag NZF is set at step No.245. No.246 to No.248
In step checks the drive direction flag DDF, and then returns the driving motor (MO) outputs a "Low" to the terminal (P ₄₎ or a terminal (P ₅₎ depending on the direction.

If the near zone flag NZF is set in the step of No.242, it means that the vehicle has finished traveling for the necessary driving amount, and then proceeds to the step of No.249 to clear the motor flag MOF. Next, in step No.250, the AF focus flag AFIF
Set F. Next, proceed to the step of No. 251, identify the terminal (P ₁₂ ), and if it is "High", return to the step of No. 145 to perform the focusing process in the single mode. There in the normal mode in the case of terminal (P ₁₂₎ is "Low", to check the after-release flag AFRF proceeds to step of No.252. If the after release flag AFRF is set, the process directly returns. If clear, the process for focusing is performed and the process returns to step No.141.

The steps after No. 253 show the subroutine for end detection. First, in step No. 253, the value of the counter is read and stored in n '. Next, in step No.254, the counter value stored in memory at the time of the last end detection
Ln ′ is compared with the counter value n ′ read this time, and n ′
When Ln ′ is equal, the encoder (EN
Since no CC) pulse is output, the process returns to step No. 256 to perform the terminal processing. n'and
If Ln 'is not equal, the lens has not reached the end and n'is stored as Ln' and the process returns to the original routine.

The steps after No. 256 show the processing when the end is detected. In step No.256, the drive signal to the motor (MO) is turned off and the motor (MO) is stopped. Next, in step No.257, the low contrast scan flag LCF ₁ is checked. Set the end flag TEF in the step of No.258 and clear the motor flag MOF in the step of No.259. Next, in the step of No.260, check the driving direction flag DDF. If it is set, proceed to the step of No.261 and set the end position flag TPF.
Is cleared to the infinity end position. Drive direction flag DDF
If is cleared, proceed to step No. 262 to set the end position flag TPF and indicate the closest end. Then, check the terminal (P ₁₂ ) in step No.263,
In the case of terminal (P ₁₂₎ is "Low" is a normal mode No.
Willing terminal to 264 of step (P _7), for re-measurement to erase outputs the display of defocus direction "High" in (P ₉₎
Return to step No.36. In the case of terminal (P ₁₂₎ is "High" Back to the step of No.36 in a single mode.

Low contrast scan flag LC in step No.257
If F1 is set, low contrast scanning is in progress, and proceed to step No.265, check low contrast flag LCF ₂ this time, and if clear, proceed to step No.269 to perform reverse scan. Set the low contrast flag LCF ₂ and proceed to step No. 27 to invert the drive direction flag DDF. Next, from No. 271 to No.
In step 273, the drive direction flag DDF is discriminated and a drive signal is output to the motor (MO) according to the direction. Then, return to step No. 36 for re-measurement. If the low contrast flag LCF ₂ is set in the step of No.265, it means that the low contrast scan is completed.
Sets a low contrast flag LCF ₃ proceeds to step clears the motor flag MOF a low contrast flag LCF _1, LCF ₂ in step a low contrast scan prohibited No.267 in steps of clear and No.268 Return to No.36 step for re-measurement after showing the stopped condition.

In addition, after assembling the circuit in the state shown in FIG. 1, only the automatic focus adjustment section was operated independently for checking and adjustment of the automatic focus adjustment section. _The following steps may be added to the flowchart in ₂ ). Here, for checking and adjustment, it is assumed that a lens having a specific fixed focal length is used. No.21
Step flag AFRF of is set then the terminal (P ₁₂₎ to determine whether "High". Then, the terminal (P ₁₂₎ is transferred to the "Low" if No.27, "High" Interested modes since No.36 steps. When it is determined that the terminal (P ₁₂ ) is "High" in the step of No. 52, it is determined whether the input / output port (P ₇ ) is in the input mode or the output mode. If the terminal (P ₇ ) is in the input mode, the mode is the single mode in FIG. 5, and the process proceeds to step No.54. On the other hand, if the terminal (P ₇ ) is in output mode, the first
In the state shown in the figure, the check mode is set, and in this case, it is fixedly stored in the ROM in the microcomputer. Set the conversion coefficient of the above-mentioned specific lens for calculation and
Move to operation 0. Also, in the step of No.139, the terminal (P
_When it is determined that the "High" signal is being input to ₁₂ ), it is then determined whether the terminal (P ₇ ) is in the input or output mode. If it is the input mode, the single mode is selected. If the output mode is .145, go to step No. 141.

If the above steps are added, even in the state of FIG. 1,
The control microcomputer (MC
Regardless of ₁ ), the AF microcomputer (MC ₂ ) operates independently, and it is possible to check and adjust the operation only with the automatic focus adjustment section. In addition, in the step of No. 52, the terminal (P ₁₂ )
Is determined to be “High”, and the terminal (P ₇ ) is determined to be in output mode.
Output the CCD output data from the input / output port (not shown) or the serial data output terminal, then read the adjustment data and move to the No. 60 step. If (P ₁₂ ) is “High” and the terminal (P ₇ ) is in the output mode, the calculated defocus amount Δε can be output for checking / adjustment, so that checking / adjustment can be further performed. It will be easy.

In the steps # 4 to # 11 in the flow of FIG. 2 described above, the setting switches (TSS), (ASS), (IS
When S), (MOSS), (UPS), or (DOS) is operated, the AF microcomputer is activated only in FA mode, but instead, the following is also possible. Is. That is, when the control microcomputer is activated, the AF microcomputer is also activated at all times, and the lens drive may not be performed only when activated by the setting switch in the AF mode. Further, when the setting switch is activated in the AF mode, the display in the FA mode may be performed.

Also, as soon as it is determined in step No. 86 in FIG. 8 that the low contrast flag LCF ₁ has been reset,
You may return to the step of No. 36 and omit the steps of No. 87 to No. 92. With this configuration, when the contrast becomes suddenly low, the photographing lens is driven toward the in-focus position based on the detection result immediately before the low contrast, and the detection result immediately before the low contrast is obtained. If the low contrast disappears before reaching the in-focus position, the shooting lens is driven to the in-focus position based on the detection result when that happens, and the low-level contrast is reached until the in-focus position based on the detection result immediately before the low contrast is reached. If the contrast remains as it is, the taking lens is driven to the in-focus position based on the detection result immediately before the low contrast.

Table 5 shows each signal name of the AF microcomputer (MC ₂ ) and its contents.
Table 6 shows the contents of each flag shown in the flow charts of FIGS. 6 to 11.

EFFECTS OF THE INVENTION According to the present invention, when the focus detection result is unreliable, for example, when the contrast of a subject image is low, the focusing lens is forcibly driven over a predetermined range to have a forcible scanning means for searching for a reliable position. In the above, since the operation of the forced scanning means is prohibited while the focusing lens is being driven toward the in-focus position, the focusing lens is in the middle of approaching the in-focus position, for example, in front of the camera. Even if the focus detection result becomes temporarily unreliable due to something crossing or the camera vibrating due to camera shake, it is not forcibly driven and deviated from the in-focus position.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a camera system to which the present invention is applied, and FIG. 2 is a block (LE) of FIG.
Circuit diagram showing a concrete example of (COV), FIGS. 3 and 4 are flowcharts showing the operation of the control microcomputer (MC ₁ ) in FIG. 1, and FIG. 5 is a microcomputer (MC1) in FIG. FIG. 6 to FIG. 11 are flow charts showing the operation of the AF microcomputer (MC2) shown in FIGS. 1 and 5 when the (MC2) is operated independently. Is. LE: Photographic lens, MLMC; Light receiving part, MLC, MO; Driving means, No.60, No.135; Detection means No.62; Reliability judgment means No.72-80; Forced scanning means No.65; Drive judgment means

Continuation of front page Examiner Shuji Omoto (56) References JP-A-58-63903 (JP, A) JP-A-57-196219 (JP, A)

Claims (3)

[Claims] 1. A focus detecting means for detecting a focus state of a photographing lens, a focus position of a focusing lens of the photographing lens is calculated based on the focus detection result, and a focus adjustment for driving the focusing lens to the focus position. Means, repeating means for repeatedly performing the focus detection during the operation of the focus adjusting means, and when a focus detection result is obtained during the operation of the focus adjusting means, based on the newly obtained focus detection result, Update means for updating the focus position, reliability determination means for determining whether or not the detection result of the focus detection means is reliable, and the reliability determination means determines that the focus detection result is not reliable, Forced driving of the focusing lens within the shooting lens over a specified range to find a focusing lens position that provides reliable detection results. In the automatic focus adjusting device having a scanning means, it is determined that the drive determining means for determining whether or not the focusing lens driving operation by the focus adjusting means is in operation, and the focusing lens drive by the focus adjusting means is in operation. In this case, the operation of the forcible scanning means is prohibited, and when it is determined that the focusing lens drive by the focus adjusting means is not in operation, a control means for permitting the operation of the forcible scanning means is provided. Automatic focus adjustment device. 2. The reliability determining means determines that the detection result of the focus detecting means is unreliable when the contrast of the subject image formed by the photographing lens is lower than a predetermined level. An automatic focus adjusting device for a camera according to claim 1. 3. The stop means for stopping the focus adjusting operation when it is determined that the detection result of the focus detecting means is unreliable during the operation of the focus adjusting means, and the focus detection result in the stopped state. 3. The automatic focus adjusting device for a camera according to claim 1, further comprising a resuming means for resuming the operation of the focus adjusting means based on the above.