JPS63172227A - Auto-focusing device - Google Patents

Abstract

PURPOSE:To improve the maneuverability of the titled device at the time of using auxiliary light by executing the same operation as an one-shot mode independently of an AF operation mode at the time of using the auxiliary light, and when external light is turned to a bright state, restoring the current mode to the original mode. CONSTITUTION:When auxiliary light ALED is used due to a drop in the luminance of an object at the time of selecting a servo mode, the number of times of radiation is reached to the restricted number of times on the way of focusing in the continuous radiation state of auxiliary light based upon the control of the servo mode, the radiation of auxiliary light is inhibited and the maneuverability is remarkably lossed. Even if the servo mode of a camera is selected, a computer PRS executes the same control as the one-shot mode forcedly at the time of using auxiliary light, and when external light is turned to the bright state, the current mode is returned to the servo mode operation. Consequently, the maneuverability at the time of using the auxiliary light can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic focus adjustment device for a camera or the like, and particularly to an automatic focus adjustment device that uses auxiliary light.

[Conventional technology]

Conventionally, as a method for adjusting the focus of a camera, the light flux from the subject that has passed through the photographic lens is received by a charge storage type photoelectric conversion element such as a CCD and the charge is stored. A known method is to perform re-accumulation while illuminating the subject with auxiliary light, detect the focus state of the photographic lens from the output, and drive the photographic lens based on the detection result. Furthermore, in many cases, the number of times the auxiliary light is irradiated is limited to a finite number of times in order to protect the auxiliary light source and save power.

Furthermore, the camera focus adjustment device is used in a so-called "one-shot mode," in which once focus is achieved, the focus is not adjusted again until an external member is operated.
The so-called "servo mode 1" J, which continuously adjusts the focus regardless of the past focus state, is widely known.

However, when the user selects the servo mode and the fill light is used due to a drop in subject brightness, focus adjustment is performed continuously with the fill light illuminated according to the control of the servo mode. In the middle of the process, the number of irradiations mentioned above is reached and the auxiliary light irradiation is no longer performed, which has the disadvantage of significantly impairing operability.

The purpose of the present invention is to solve the above-mentioned problems, and its gist is to force the camera to perform the same control as the one-shot mode when using the auxiliary light even if the servo mode is selected. Furthermore, by returning to the servo mode operation when the outside light becomes brighter, it is possible to adjust the focus with improved operability when using the auxiliary light.

〔Example〕

FIG. 1 is a circuit diagram showing an embodiment of a camera equipped with a keyed focus device according to the present invention. In the figure, PR3 is a camera control device, for example, an internal ROM.

It is a chip microcomputer with RAM and A/D conversion functions, and it performs functions such as automatic exposure control function, automatic focus detection function, film winding, rewinding, etc. according to the program described later stored in ROM. is performing the following actions.

The microcomputer PR8 has a communication signal so.

SI and 5CLK are used to communicate with peripheral circuits and lenses, and to control the operation of each circuit and lens.

SO is the data signal output from PR3, SI is PR3
The data signal input to 5CLK is the signal So, SJ
This is the synchronization signal.

LCM is a lens communication buffer circuit, and when the camera is in operation, the lens power supply VL is applied to the lens, and the signal CLCM from the microcomputer PR3 is at a high potential level (hereinafter abbreviated as "H", and a low potential is 'L'). ''), it serves as a buffer for communication between the camera and the lens.

When the microcomputer PR8 sets the signal CLCM to "H" and sends out the predetermined data as an SO multiplied signal in synchronization with the 5CLK signal, the circuit LCM is designated and the SCLK signal is sent through the camera-lens junction. , SO-multiplied signals LCK and pCL are output to the lens. At the same time, the buffer signal of the signal DLC from the lens (the part surrounded by the dashed line) is outputted as the Sr signal, and the computer PR3 inputs the lens data as the Sr signal in synchronization with the SCLK signal.

SDR is a drive circuit for the line sensor device SNS for focus detection, and the signal C3DR from the computer PR3 is “
H'' (7), it is selected and controlled by the computer PR3 by the So, SI, and 5CLK signals.

The SNS is, for example, a pair of CCD line sensors CCD.

This is a sensor device including a CCD2. φ1. φ2 receives the clock CK from the computer PR3 and drives the drive circuit SD.
CCD driving clock generated by R, S I-1
is the line sensor CCD, a signal that transfers the charge accumulated in CCD2 to the transfer section, CL R is the line sensor CC
D, is a clear signal for clearing the accumulated charge in the CCD2, and each of these signals is formed by a drive circuit SDR controlled by a computer PR3.

The output signal O8 of the sensor device SNS is the clock φ1゜φ2
A sensor CCD, which outputs in chronological order in synchronization with.

It is an image signal accumulated in each power supply of CCD2, and CCD,
.

Each bit of the CCD2 is outputted and amplified by the amplifier circuit in the circuit SDR, and then sent to the computer P as an AO3 signal.
It is input to R8. The computer PR3 inputs the AO3 signal from the analog input terminal, synchronizes with the CK multiplied signal, and uses its internal A/D conversion function to sequentially store the signal at a predetermined address in the RAM after A/D conversion.

Same (the AGC signal which is the SNS output signal is the device SN
This is the output of the storage control sensor in S, is input to the circuit SDR, and is used to control the storage time of the sensors CCD, . . . CCD2.

The SPC is a photometric sensor that receives light through the photographic lens, and its output of 5 spc is input to the analog input terminal of the computer PR3, and after A/D conversion, it is used for automatic exposure control (
AE).

DDR is a switch sense and display circuit, which is selected when the signal CDDR from the computer PR3 is "H", and communication with the computer PR3 is controlled by the So, ST, and 5CLK signals.

That is, the switch state of the switch group SWS is changed based on the data sent from the computer PR3, and switches sw, , sw, which are linked to the release button, are turned on and off in conjunction with various operating members. to computer PR3.

MDRI and MDR2 are drive circuits for film feeding and shutter charging motors MTRI and MTR2, and signal M
] Execute forward/reverse rotation of the motor using F, MAR, M2F, and M2R.

MCI and MG2 are the magnets for starting the movement of the shutter front curtain and rear curtain, respectively, and the signals 5MG2, 5MG2. The amplifying transistors TRI and TR2 are energized, and the computer PR8 performs shutter control.

ALED is an auxiliary light source for projecting light onto the subject when the brightness is low, and the signal from the output terminal S A L of the microcomputer PR3 is
By setting it to H''', the drive transistor ATR is driven and auxiliary light is emitted via the optical system ALNS.
The LED is composed of, for example, a light emitting diode.

In addition, switch sense and display circuit DDR.

The motor drive circuits MDRI, MDR2, and shutter control are not directly related to the present invention, so detailed explanations will be omitted. Control circuit LP in the lens in synchronization with synchronization signal L CK
The signal DCL input to R3 is data of a command from the camera to the lens, and the operation of the lens in response to the command is determined in advance.

The control circuit LPRS analyzes input commands according to a predetermined procedure, performs focus adjustment and aperture control operations, and outputs DLC.
Various parameters of the lens (open F-number, focal length, defocus amount vs. extension amount coefficient, etc.) are output.

The example shows an example of a single lens that extends entirely, and when a focus adjustment command is sent from the camera, the focus adjustment motor L M T R is activated according to the drive amount and direction sent at the same time. On the other hand, signals LMF and LMR are sent out to drive motor LMR to move the optical system in the optical axis direction and perform focus adjustment. The amount of movement of the optical system is determined by the encoder circuit EN.
C signal 5ENC is monitored, and when the specified movement is completed, the signals LMF and LMR are set to "L".
” to control the motor LMTR.

When an aperture control command is sent from the camera, a known Stella Pink motor DMTR that is linked to the aperture mechanism is driven in accordance with the number of aperture stages sent at the same time. Furthermore, since the Stellar Pink Motor can be controlled in an open manner, it does not require an encoder to monitor its operation.

Next, the operation shown in FIG. 1 will be explained using FIGS. 2 to 4.

First, when a power switch (not shown) is operated, power is supplied to the microcomputer PR8, and the microcomputer PR3 executes a stored program.

FIG. 2 is a flowchart showing the overall flow of the above program. When the execution of the above-mentioned storage program is started, in step (002), the state of the switch SWI, which is turned on by the first step operation of the shutter button (not shown), is detected, and when the switch SWI is off, the state of the switch SWI is detected. At (005), all hooks inside the microcomputer PR3 are set to "o", and all variables to be described later are set to "'O".

The above steps (002) and (005) are performed by the switch S.
It is executed repeatedly until WI is turned on, and the switch SWI
When turned on, the process moves to step (003).

Step (003) is an AE control subroutine,
This AE subroutine performs a series of controls such as photometric calculation processing, exposure control, shutter charging after exposure, and film winding. The AE subroutine described above has no direct relation to the present invention, so a detailed explanation will be omitted, but its outline is as follows. As long as the switch SWI is on, photometry and exposure control calculations are performed each time this AE subroutine is executed. Also, when the second step interval operation of the shutter release button is performed and switch SW2 is turned on, the release operation is performed by interrupt processing, and the aperture is adjusted according to the exposure amount determined by the above exposure control calculation. After the exposure is completed, the shutter churn and film feeding operations are performed.

Assuming that the first step interval operation of the shutter hocun is now performed, the process moves to step (004) after photometry and arithmetic processing are performed in step (003). The above-mentioned interrupt operation is performed when the AE operation mode is so-called
・When in ``Manual mode,'' permission is granted after the first photometry is completed after the power switch is turned on, and
The AF operation mode is "one-shot mode". In other words, in the above-mentioned "servo mode" or "manual mode", release operation is possible at any time regardless of focus adjustment operation, and in "one-shot mode", focusing is detected. It is only then that the camera can be released. Furthermore, A.E.
The mode is selected by a mode switch (not shown), and in "one shot mode", once the focus is focused, the switch SWI
The AF operation is not performed again until it is turned off, and the AF operation is always performed in "servo mode".

In the AF sub-control step (004), the focus adjustment state of the photographic lens is detected and the photographic lens is driven so that it is in focus if it is in "one shot mode" or "servo mode", or it is driven to bring it into focus if it is in "manual mode". Displays only whether the camera is in focus or out of focus. Further, in the manual mode, AF sub-control using auxiliary light is not performed.

In the above-described flow, as long as the switch SWI is on, the AF sub-controls (003) and AF sub-controls (004) are alternately and repeatedly performed.

Step (O O 4.) is an AF control subroutine, and the AF control subroutine shown in FIG. 3 is executed.

Step (102): By shutter release operation,
Immediately after shooting one frame, it is determined whether or not the first AF sub-control is performed (it is determined whether film feeding was performed in the AF control subroutine that was performed immediately before), and the mode is set to "Continuous shooting mode". ” or not. When it is determined that step (102) has been performed for the first time after the end of shooting, it is assumed that ΔF is in continuous shooting mode, and step (102) is performed.
At step 103), all flags in the microcomputer PRS are set to "O", and "o" is set to all variables. As a result, the past AF sub-control status is initialized during the "continuous shooting mode", and in the next step (104), the continuous shooting mode flag FAF is set to 1 to remember that there is AF sub-control during continuous shooting, and in step (104), the AF sub-control status is initialized. 1.09). Further, in step (105), the set state of the flag PRMV is detected. The flag PRMV is a "lens drive flag", and if the previous AF sub-control lens drive has not been performed, the flag (105) is set to "0", the process moves to the flag (109), and the AF sub-control is performed again. Conversely, if the lens was driven last time, it is determined in the next step (106) whether or not the lens has stopped driving.

In step (106), as explained in FIG. 1, the microcomputer PRS controls the lens communication buffer circuit, LCM.

It communicates with the lens LNS via the in-lens control circuit LPRS, and checks the state of the lens by receiving a monitor signal. If the lens is not stopped now, the lens is being driven, so the AF control subroutine ends. Therefore, as long as the lens is in the driving state, the determination as to whether the lens has stopped is continued in step (106). In the present invention, the AF sub-control is not performed while the lens is being driven, and the AF sub-control is performed only when the lens is stopped, so the next step (
108), set PRMV to MO" and step (1
Proceed to 09).

Step (109): Determine the autofocus mode, and if it is manual mode, step (110)
(select "Manual" using a mode switch (not shown)). Step (110) is a subroutine for inputting image signals, and steps (111) and (112)
After executing the focus detection display subroutine in step (113), the AF sub-control subroutine is ended (
Each subroutine will be explained later).

If manual mode is not selected in step (109), select "one-shot mode" in step (114,).
Determine whether or not. If the one-shot mode is selected, the process proceeds to step (115), and the state of the focus flag JF is checked to determine whether it was in the "previously focused state" or not. Here A
If the F control mode is "1 one-shot mode" and "previously focused", the AF sub-control is terminated in step (]16). That is, in the one-shot mode, once the focus is achieved, new AF sub-control is not executed until the switch SWI is turned off. The above steps (
1] If the previous focus was not achieved in 5), proceed to the next step (117).
).

Step (117) Execute the image signal input subroutine. In the image signal input subroutine, first, the computer PR3 sets C3DR to H, selects the drive circuit SDR, and transmits the SO multiplied signal to the drive circuit SDR.

This is the SO multiplied signal accumulation start command at this time, and in response to this command, the drive circuit SDR transmits the CLR signal to the line sensor device SNS, clears the CCD line sensor sensor accumulation signal, and then causes the line sensor to perform the accumulation operation for the image. CCD line sensor CCD of device SNS, CCD2
The image light beams incident through the photographing lens are incident on each sensor CCD.

The image position on the CCD 2 is determined according to the focus state.

To explain in detail, when the subject is in focus, each sensor CCD
, , the same image pattern is projected at the same position on the CCD 2, and the CCD is in the front focus or back focus state.

The image pattern on the CCD 2 is projected at symmetrically shifted positions depending on the direction and amount of focus shift.

Therefore, by detecting the amount and direction of positional deviation between the image patterns on the CCD and the CCD 2, the direction and amount of out-of-focus can be detected.

After clearing the image signal, the image pattern projected to the position according to the focus state as described above is displayed at each COD.

The CCD 2 accumulates data for a predetermined period of time, and then the signal SH and the clock φ1. φ2 is the sensor device SNS
supplied to In addition, the accumulation time of the above image pattern is SNS
This is determined based on the output AGC of the storage control sensor in the storage control sensor.

As described above, the signal SH and the clock φ1. When φ2 is supplied, the image signals accumulated in each search of each sensor CCD, CCD2 from the output end of the sensor device SNS are sent out sequentially in time series as output O8,
The signal is amplified by the amplification circuit in the drive circuit SDR and is sequentially inputted to the analog input terminal of the computer PR3 as a signal AO3. The computer PR3 uses its internal A/D conversion function to A/D convert the signal AO3 and sequentially stores the digital image signals at predetermined addresses in the RAM in synchronization with the clock CK output by itself.

With the above operation, the image signal of each sensor corresponding to the image pattern on the sensor CCD, CCD2 is converted to RA as a digital value.
It will be stored in M.

First, in FIG. 4(a), subroutine step (20
When the image signal input in step 1) is called from the AF control routine, in step (202), the flag AUXMOD (a flag that is set to 1 if the previous auxiliary light mode was used)
It is determined whether or not the previous AF sub-control was "auxiliary light mode".

If it is not the auxiliary light mode, the process moves to step (207), and if it is the auxiliary light mode, the process moves to step (203).

Step (203): Determine whether or not the predetermined number of times the auxiliary light has been emitted has been completed using the flag AUXNOEM (a flag that is set to 1 when the emitted light has been emitted a predetermined number of times). If the predetermined number of times of light emitting has been completed, the process proceeds to step (207), but if not, the process proceeds to step (204).

Step (204): Determine whether or not focus was achieved under the previous auxiliary light projection using the flag AUXJF (a flag set to l when focusing in the auxiliary light mode). If it is in focus, the process moves to step (207) without emitting the auxiliary light, and if it is not in focus, the process proceeds to the next step (205), where the auxiliary light is turned on.

For this AUXJF, subroutine "Focus detection"
As will be explained in detail below, this flag AUXJF determines whether or not focus is achieved under the auxiliary light projection, and if AUXJF is 1
If flag AUXMOD is auxiliary light mode, flag A
The auxiliary light is not emitted even under the condition that the number of times UXNOEM is emitted is less than or equal to the predetermined number of times.

Step (205) Turn on the auxiliary light.

The output signal of the output terminal S A L of the microcomputer PR3 is 1"
By setting the current to the auxiliary light source ALED through the transistor ATR, the optical system A L N
Emission of the auxiliary light starts from S.

Step (206) Auxiliary light emission counter AUXCN
Count up T by one.

Step (207) Line sensor SNS for focus detection
Allow the device to start accumulating a light image. When the microcomputer PR3 sends a 1 accumulation start command to the sensor drive circuit SDR, the sensor drive circuit SDR sets the clear signal CLR to the photoelectric conversion element section of the sensor SNS to "O" to start charge accumulation.

Step (208): Accumulation time counter INTCNT
is initially set to the initial value 0.

Step (209) Reset the 1 ms timer counter of the accumulation time timer. The counter is microcomputer P
It uses the timer function of R3.

Step (2) 0) - This flag determines whether or not the sensor has finished accumulating. It is checked whether the signal INTEND from the sensor drive circuit SDR is "]".The sensor drive circuit SDR is connected to the line sensor SNS.
At the same time as the start of accumulation, the signal INTEND is set to ``0''.
and monitors the output AGC signal of the accumulation control sensor from the sensor SNS, and when the AGC signal reaches a predetermined level, the signal INTE from the sensor drive circuit SDR is
ND is set to '1'', and at the same time the sensor drive circuit S
The charge transfer signal SH from DR is set to “H” for a predetermined time,
Control is performed so that the charge in the photoelectric conversion element section in the sensor SNS is transferred to the CCD section.

Here, if the above accumulation is completed, step (2), 5
), and if the accumulation has not finished yet, proceed to step (
Proceed to 211).

Step ('211): Determine whether the ms timer has reached the accumulation time of 1 ms. ] If ms has not been reached, the process returns to step (210), and if 1 ms has already been reached, the accumulation time counter INTCNT is incremented by one in the next step (212).

Step (2) 3) Compare the contents of the flag INTCNT with a predetermined number MAXINT. MAXINT is 1m
is the longest accumulation time expressed in units of s, and is the maximum accumulation time expressed in units of s;
If NT is less than MΔXINT, the process returns to step (209) and the process waits again for the completion of accumulation. Here INTCN
When T matches the maximum accumulation time MAXINT, the accumulation is forcibly terminated in the next step (2] 4).

The end of this accumulation is sent from the microcomputer PR3 to the sensor drive circuit SD.
The process is completed by sending an "accumulation end command" to R. When the sensor drive circuit SDR receives an "accumulation end command" from the microcomputer PR3, it outputs the charge transfer signal SH.
is set at "Ize" for a predetermined period of time to transfer the charge in the photoelectric conversion section to the CCD section.

Step (2] 5): Flag AUX, MCD
Determine whether the mode is auxiliary light mode or not. The flag AUXMO
If D is in the auxiliary light mode, the projection of the auxiliary light is turned off in step (216). That is, the output terminal S of the microcomputer PR3
Set the A L signal to “0°” to disable the floodlight source ALED. Regarding step (216), there is no adverse effect even if this step is executed when the auxiliary light mode is not set, so steps (21, 5) and (2]6) may be omitted.

Step (217): A comparison is made between the accumulation time counter TNTCNT and a predetermined constant AUXINT. Above AUX
INT is the low luminance accumulation time expressed in accordance with the accumulation time, and when TNTCNT≧AUXINT, the low luminance flag L L F L G in step (219) is set to “1”.
", and when INTCNT is less than AUXTNT, the low luminance flag LLFLG is set to "0''.

In step (220), the A-
D conversion and storage into a predetermined address of the RAM are performed in the microcomputer PR8, and in step (221) the process returns to the main routine, ie, step (118).

Step (118): Determine whether or not it is continuous shooting mode using flag FAF.

When the flag FAF is 1, that is, in continuous shooting mode, the process moves to the next step (121), and when it is 0, the process moves to step (11).
Proceed to 9). The flowchart regarding the auxiliary light after step (119) is shown, and when the flag FAF is ], the process moves to step (121), so that no processing regarding the auxiliary light is performed for continuous shooting.

Step (]] 9) Determine whether or not it is the auxiliary light mode using the flag AUXMOD.

Flag ΔUXM if the previous AF sub-control auxiliary light mode
OD is 1, and the process moves to step (128). When the flag AUXMOD is 0, the process proceeds to step (120), and it is determined whether or not the brightness is low by checking the flag LL F L G. The flag L L F L G is the above-mentioned subroutine "
If the flag is set in the "image signal input" and is 1, that is, the brightness is low, the process moves to step (128), and if the brightness is not low, the process moves to step (] 2 ], ).

Steps (128) to (135) are an auxiliary light control flow at low brightness.

Step (128): This flag determines whether the auxiliary light unit is attached to the camera. Here, the determination is made by detecting the state of a switch (not shown) that is turned on when the auxiliary light unit is attached to the camera.

If the auxiliary light unit is not attached to the camera, the process moves to step (121) and the AUXMOD is set to “O”.
to cancel the auxiliary light mode.

If the auxiliary light unit is installed, step (1)
29) Set "P" in AUXMOD to set the auxiliary light mode.Here, in step (1) 9) above, set flag A.
The above step (1) is also performed when the UXMOD is in the auxiliary light mode.
, 29), but this is done for convenience of the program sequence progress of the present invention.

Step (130): Determine whether the counter AUXCNT is set to "O".
CNT is a variable that is counted in step (206) in the above-mentioned "image signal input" subroutine, and increases by one when an image signal is accumulated in the photoelectric conversion element under illumination of an auxiliary light. . Furthermore, this counter AU
XCNT is cleared in step (005) of the flowchart shown in FIG. 2 when the switch SWI is off, and is cleared in step (005) of the flowchart shown in FIG. Cleared in step (103).

Therefore, counter AUXCNT = "0" means that this is the first time in the sequence progress that the auxiliary light mode is in effect, and if it is the first time in the auxiliary light mode, the process advances to step (131) and the AF is activated by the current image signal input. Sub-control ends.

That is, the image signal input in step (117) is discarded, and a new image signal is input under the next AF sub-control auxiliary light projection. Therefore, it can be considered that the image signal input in step (117) was used only for determining brightness.

On the other hand, if the counter AUXCNT is not "0", then the auxiliary light mode has already been entered, so in step (132), the counter AUXCNT is compared with a predetermined constant AUXNUM.The AUX and NUM are the limited number of times the auxiliary light is emitted. ,
This counter AUXCNT is the light emission limit number of times AUXNUM.
When the value is less than 1, the process moves to step (122) and a "focus detection" subroutine is executed.

The counter AUXCNT is AUXCNT≧AUXNU
M (However, in the actual sequence, AUXC
NT>AUXNUM does not occur) The process moves to step (133).

Step (133): Determine whether or not the number of auxiliary light projections has been completed using the flag AUXNOEM. Flag AUX
In NOEM, the number of times the auxiliary light is emitted has already reached the predetermined constant AU.
When it is determined that the auxiliary light has been emitted three times, the number of times the auxiliary light has been emitted is completed, and the auxiliary light is not emitted any more. In other words, even if flag A and UXMOD are 1 in the subroutine for "image signal input" and the auxiliary light mode is in effect, if the flag AUXNOEM is 1 and the number of auxiliary light projections has been completed, the image signal is stored. The fill light will no longer be emitted.

In step (133), if the flag AUXNOEM indicates that the number of light projections has been completed, the process moves to step (134,).

Step (134): Determine whether the brightness is low based on the flag LLFLG.

As mentioned earlier, this flag L L F L G is a low brightness flag that is set in the "Image signal input" subroutine, and the number of light projections has been completed with the flag AUXNOEM.
Determining the brightness using the flags L L F I and G means determining the brightness in a state where the auxiliary light has already been emitted a predetermined number of times under the auxiliary light mode and is no longer emitted. be. Here, if the flag LLFLG is not low brightness, the process moves to step (12), ), sets the flag AUXMOD to 0'', cancels the auxiliary light mode, and proceeds to the next step (122). L L
If it is determined that FLG is not low brightness, when the brightness increases in the above-mentioned state, the auxiliary light mode is canceled and the normal mode returns, and the A and F control in the normal mode is restarted.

If the process moves to the above steps (12] and
), when the flag AUXMOD is not in auxiliary light mode,
This is when it is determined in the next step (120) that the flag LLFLG is 0, indicating that the brightness is not low. That is, when the camera is not in the AF sub-control auxiliary light mode and the subject brightness is not low, the process moves to step (121).

On the other hand, if the flag LLFLG is 1 and it is determined that the brightness is low, the process directly proceeds to the next step (122), ``focus detection''.

In the above flow, in step (133) the flag AU
Flag L only when XNOEM has completed the number of times the auxiliary light has been emitted.
LFLG determines whether the brightness is low or not.

The reason for this is that when detecting the brightness of the subject under fill light projection, the brightness of the subject increases by 1 due to the influence of the fill light, and the true brightness of the subject cannot be determined. When the number of times the auxiliary light is projected is less than a predetermined value, no determination is made as to whether the brightness is low or not.

Next, the focus detection subroutine in step (122) will be explained using FIG. 4(b).

Step (303): Using the flag AUXJF, it is determined whether or not the focus was achieved under auxiliary light projection in the past.

When the focus is under the auxiliary light, the step (
304).

Step (304): The state of the flag LL F L G is detected, and it is determined whether the brightness in the state where the auxiliary light is not emitted is low brightness or not. Here flag L L F L
When G is 1 and the brightness is low, the next step (305)
AF sub-control ends. On the other hand, the flag L L F L
When G is O and the brightness is not low, the subject brightness has increased, so the process proceeds to step (306), where the auxiliary light mode flag AUXMOD and the number of flashing completion flag AUXN are set.
OEM, clear the focus flag AUXJF to '0',
Furthermore, the auxiliary light counter flag AUXCNT is cleared to 0''.

The operations of steps (303) to (306) above will now be described in detail. If the flag AUXJF is 0, that is, the focus was previously achieved under the projection of the auxiliary light, this means that the current image signal is a signal in which the auxiliary light is not projected. That is, when it is determined in step (204) in the above-mentioned "image signal input" subroutine that the flag AUXJF is "]", the auxiliary light is not turned on. Therefore, the flag LLFLG determined in the above step (304) determines the brightness without the auxiliary light being emitted. This indicates that even though the image has been focused, the subsequent brightness is still low. In this state, that is, after focusing under the auxiliary light projection,
In step (305), the AF sub-control is not performed when the brightness is low, and the focus is maintained, and the operation is the same as the AF sub-control one-shot mode at this time.

On the other hand, if the flag LLFLG is 0 and it is determined that the brightness is not low, it means that the brightness without the fill light is no longer low after focusing with the fill light, and step ( In step 306), flags and counters related to the auxiliary light are cleared and AF sub-control is started again.

As described above, in the auxiliary light mode, the AF control mode operates in the one-shot mode or the servo mode, regardless of whether the AF control mode is operating in the one-shot mode or the servo mode.

In this case, when the subject brightness is low, as described above,
The one-shot mode continues, but the brightness of the subject changes depending on the surrounding situation, and when it is not low brightness, AF is activated.
When the control mode is ZARPO mode, the AF sub-control of Thermo-1 and AF is started again in a double sequence, and step (3) is started.
Proceed to 07).

Step (307) Defocus amount D of the photographing lens is determined from the image signal from the above-mentioned "image signal input" subroutine.
Perform the EF calculation.

Here, the amount and direction of deviation until in-focus are calculated as defocus-JiDEF based on the digital values corresponding to the image patterns of the sensors CCD and CCD2'' obtained in the image signal input subroutine described above.

The specific method of calculating this defocus amount is not directly related to the purpose of this application, so a detailed explanation thereof will be omitted. Therefore, by comparing and processing the digital values of each of the above-mentioned sensors corresponding to the pattern and determining the degree of coincidence of the data, the maximum deviation and direction of deviation from the in-focus state, that is, the defocus 1DEF can be determined. be.

Step (308): Compare the defocus amount DEF and the constant value JFFLD.

Here, when DEF>JFFLD, step (3
10), sets the focus flag JF to "0", completes the focus detection subroutine, and proceeds to step (123) in FIG.
).

On the other hand, when it is determined that JFFLD>DEF, the focus flag JF in step (309) is set to "1" and the process proceeds to step (312). Here, the above-mentioned J F F L D represents a constant focusing state.

Step (312): Determine whether or not it is the auxiliary light mode using the flag AUXMOD.

If flag AUXMOD is auxiliary light mode, step (3)
13), the flag AU was activated due to focusing under the auxiliary light.
XJF is set to "1", the focus detection subroutine is ended, and the process moves to "display" in step (123) in FIG.

Step (123): For "r display", refer to A above.
The F sub-control focus state is simply a function of displaying whether or not the focus state is in focus using a display member, so a description thereof will be omitted.

Step (124): Determine whether or not focus is achieved using flag JF.

Flag TF is a flag stored in the above-mentioned ``single focus detection'' subroutine, and when this flag JF determines the in-focus state, that is, when it is in focus, the AF is activated in step (127).
When the sub-control is completed and it is determined that the lens is not in focus, the process proceeds to step (125) and a lens drive subroutine is performed.

In the lens drive subroutine, the microcomputer PR3 outputs the signal C.
Set LCM to "1" to specify the buffer circuit LCM.

In addition, the lens driving amount is transmitted to the circuit LCM as an SO multiplied signal,
The SO multiplied signal is transmitted to the control circuit LPR3 as the DCL signal. The circuit L PRS sets the signal L M F or LMR to H in accordance with the amount of lens drive, causes the motor to rotate the MTR in a predetermined direction, and moves the photographic lens LNS in the optical axis direction. The amount of movement of this lens is determined by the encoder ENC, which outputs a signal 5ENC corresponding to the amount of movement.
It is compared with the signal representing the defocus etc. transmitted to the ENC and circuit LPR3, and when both signals match, the signal L is output.
MF and LMR are set to L, rotation of the motor LMTR is stopped, and lens driving is completed.

With the second operation, the lens moves by an amount corresponding to the defocus I, and the lens drive subroutine is completed, and step (
In step (126), the lens drive flag PRMV is set to "1", and in step (127), the AF sub-control is ended.

Next, the lens drive subroutine step (
401) will be explained in detail.

Step (4,02): Input "coefficient S of defocus amount vs. extension amount" from the photographic lens. The defocus amount is the aforementioned DEF, and the extension amount represents the amount of movement of the lens that performs focus adjustment in the optical axis direction.

The above coefficient S is 1 when the above photographing lens is a standard lens:
+i S = 1, and if the photographing lens is a zoom lens, the coefficient S changes depending on the zooming position.

Step (4,03): Input the feed-out amount PT■-■ corresponding to one tooth of the r encoder. When the lens that performs focus adjustment moves, a pulse is generated from the encoder in conjunction with this movement, and the projected scene PTH corresponding to the encoder l tooth represents the amount of movement of the lens per tooth.

Step (404): Previously detected defocus amount DE
F, and the coefficient S of the defocus amount vs. the amount of feedout described above.
In addition, an integer value FP representing the amount of movement of the focusing lens in terms of the number of teeth of the encoder is calculated by the following equation using the feed-out inertia PTH corresponding to one tooth of the encoder.

FP=DEFXS/PTH Step (,11,05): The integer value FP obtained in step (404) above is sent to the photographing lens as the lens drive amount to instruct lens drive, and in step (4-06) End lens driving.

As detailed above, after determining that the AF control is not in continuous shooting mode, if the subject brightness is determined to be low and the accumulation time in the sensor becomes long, the AF control is set to fill light mode.
Fill-in light is emitted, but when the subject brightness becomes bright even when the fill-in light is being emitted, it is generally considered that the fill-in light should be controlled to be centered. The amount of charge that accumulates in the storage section in the sensor in the state of In other words, when emitting the auxiliary light, the brightness is not monitored to determine whether to stop emitting the auxiliary light next time.In this state, the flag AUXNOEM is set to the predetermined auxiliary It is not determined whether the brightness of the object is low until the number of times of light projection is completed, and only after the completion of the predetermined number of times of light projection is completed, the flag L L is set in the next step (1, 34,).
FTG is used to determine whether the brightness is low or not.

Furthermore, after executing the image signal input subroutine in step (117), the flag F A F in step (118) is
Then, it is determined whether the photographing mode is a continuous photographing mode or not, and if it is a continuous photographing mode, the auxiliary light mode is canceled in step (121) and the focus detection subroutine is executed after returning to the normal mode.

In other words, when performing AF control in continuous shooting mode,
The storage time in the sensor storage unit is monitored during continuous shooting, and when the brightness of the subject decreases, the operation of storing the light in the sensor again with the auxiliary light emitted is not performed. The reason for this is to shorten the storage time by avoiding wasteful storage time due to re-storage in the sensor storage section. Also, if the fill light is emitted during continuous shooting, the fill light will continue to be emitted while the switch SWI is on, so if a light emitting diode is used as the fill light source, for example, This is because the amount of energy used exceeds the energy limit.

Furthermore, in the focus detection subroutine of step (301) in FIG. 4(b), the AF control inputs an image signal in servo mode, and in step (303), the flag AUXJF indicates that the focus was previously focused under the auxiliary light. If it is in focus, the flag LLFLG detects the brightness of the subject without the auxiliary light in the next step (304), but if it is determined that the brightness is low here, the next step step (305
) to enter one-shot mode without performing AF control.

This is so that even if it is determined that the brightness is low in the one-shot mode, when the auxiliary light is used, the AF control mode and one-shot mode are operated, and when the focus is focused, the in-focus state is fixed. By using the one-shot mode, it is possible to prevent the energy limit of the light emitting element from being exceeded as described above due to repeated projection of the auxiliary light in the servo mode. Furthermore, even if the servo mode is switched to the one-shot mode as described above, when the subject brightness increases and becomes brighter, AF control is performed again in the servo mode. (In the case of servo mode, image signals are continuously accumulated.

) In the embodiment, an LED is used as an auxiliary light source, but an electronic flash tube or a light bulb may also be used.

In the embodiment of the present invention, the subject brightness is detected based on the accumulation time of the sensor.
If an independent sensor such as Sadakawa is provided and the subject brightness is constantly detected using its output, brightness detection can be performed even while the auxiliary light is being set, and the effects of the present invention will be even more significant.

〔Effect of the invention〕

According to the present invention, when using the auxiliary light, the same operation as the one-shot mode is performed regardless of the AF operation mode, and the original mode is returned when the outside light becomes brighter. This enables automatic focus adjustment with improved operability when using an auxiliary light.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment to which a focus detection device according to the present invention is applied, and FIGS. 2, 3, and 4(a). (b) and (c) are explanatory diagrams showing a program for explaining the operation of the embodiment in FIG. 1;

Claims (2)

[Claims] (1) A light receiving section that receives the light flux from the subject that has passed through the photographic lens; a signal processing means that uses the output of the light receiving section to detect the focal state of the photographic lens; and based on the output of the signal processing means. a lens driving means for moving the photographing lens to a focused state by using the lens; a detecting means for detecting the brightness of the subject; an auxiliary light source for illuminating the subject; In an automatic focus adjustment device for a camera having a control means for controlling light emission, the automatic focus adjustment device has a first mode in which the operation is inactive after detection of a focus state, and a first mode in which the operation is inactive after detection of a focus state, and a first mode in which the operation is disabled regardless of a past focus state. An automatic focus adjustment device for a camera, having a second mode of operation, and comprising forcing means for forcing the automatic focus adjustment device into the first mode when the control means is activated. (2) Claim 1, characterized in that the operation of the forcing means is prohibited upon receiving a signal from the detection means.
The automatic focusing device for the camera described in Section 1.