JPH08262317A - Automatic focus detecting device of camera - Google Patents

Abstract

PURPOSE: To improve the focusing rate, shorten the time required for range finding operation, and enable speedy photographing operation by selecting a reliable control signal out of control signals in determined order. CONSTITUTION: The quantities of received light accumulated as electric charges in line sensors 27 and 28 are sent as electric signals (small set signal) to a CPU 50 through quantization parts 39 and 30 and an arithmetic part 31. The CPU 50 has a function as a range finding operation means which obtains a range finding signal by performing range finding operation with small set signals from plural small areas, a function as a reliability judging means which judges the reliability of each obtained range finding signal in predetermined order as to plural small photodetection areas, and a function as a determining means which determines the range finding signal from a small photodetection area judged firstly to be reliable as a current range fiding signal. Further, a ROM is stored with data that are so programmed as to judge the reliability of the range finding signals in specific order.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a passive type automatic focus detection device mounted on a camera and utilizing external light.

[0002]

2. Description of the Related Art Conventionally, there is known a lens shutter type camera equipped with a passive type automatic focus detection device (hereinafter referred to as an AF device). In such a camera, a focus detection optical system, a pair of left and right line sensors that have a plurality of light receiving elements in a line and project a plurality of subject images relating to the same subject by the photographing optical system, and detection data of the line sensors And a calculation unit that detects the focal length based on the above.

In such a camera, it is known that a large number of light receiving elements of a line sensor are used as one light receiving area and a distance measurement operation is performed based on sensor data (distance information) obtained from this light receiving area. However,
In this way, the structure for performing distance measurement calculation using one light receiving area has only one opportunity for distance measurement calculation, and if a proper value cannot be obtained by one distance measurement calculation, focusing becomes impossible, You will miss a photo opportunity.

To alleviate this problem, the left and right line sensors are constructed by dividing a large number of light-receiving elements each into a plurality of blocks (small light-receiving regions), and a pair of small light-receiving regions corresponding to each line sensor is used. A camera that performs distance measurement calculation based on the obtained sensor data has also been proposed. However, this camera has a configuration in which a plurality of distance measurement values obtained based on sensor data from each small light receiving area are compared with each other to detect a maximum value corresponding to the closest distance, and focusing is performed based on the detected maximum value. Therefore, it is necessary to perform such a comparison operation of the respective distance measurement values each time the distance measurement is performed, which goes against the speedy shooting operation.

[0005]

SUMMARY OF THE INVENTION The present invention has been made on the basis of the awareness of the problems in the above-mentioned conventional cameras, and can provide a speedy photographing operation which can increase the focusing rate and shorten the time required for distance measurement calculation. It is an object of the present invention to provide an automatic focus detection device for a camera capable of performing the same.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a photographic optical system having a variable focal length; and optical axes which do not match the optical axis of the photographic optical system and are arranged at a distance of a base line from each other. A focus detection system including a pair of imaging lenses and a pair of line sensors for forming a subject image by the imaging lenses;
Each of the line sensors has a size facing the maximum angle of view of the photographing optical system, and the signal from the line sensor receives a plurality of different small light-receiving areas for receiving object images within different angles of view. In the automatic focus detection device of the camera used as the small set signal of the above, the distance measuring calculation means for performing the distance measuring calculation respectively by the small set signals from the plurality of small light receiving regions, and the distance measuring calculation means. Reliability determination means for determining the reliability of each distance measurement signal in accordance with a predetermined order for the plurality of small light receiving areas; Determining means for determining the distance measurement signal as the distance measurement signal at that time;
It is characterized by having.

The plurality of small light receiving areas are located on the first center of the line sensor and partially overlap the first light receiving area on both sides of the first light receiving area. With the second and third light receiving regions located,
For example, when the distance measurement signal by the second or third light receiving area is adopted, it becomes possible to focus on a position closer to the center of the subject.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to illustrated embodiments. 1 is a front view of a camera to which the present invention is applied, and FIG.
Is a rear view and FIG. 3 is a plan view. This camera 11 is A
This is a lens shutter type camera in which the optical axes of the focus detection optical system, the taking lens, and the finder optical system of the F device do not match.

As shown in FIG. 1, the camera 11 has a photographing lens (photographing optical system) 13 including a power zoom lens, a remote control light receiving section 14, a self-lamp 10, in a front portion thereof.
Metering window 15, AF auxiliary light projecting section 16, finder window 17,
It has a passive AF module (AF device) 18 and a stroboscopic light emitting section 19, and has a finder eyepiece window 24, a main switch 65, a zooming lever 21 and a back cover 22 at the rear.
have. A release button 20 and an external LCD display section 23 are provided on the upper surface of the camera 25.
A strobe switch 40, a mode switch 41, a date switch 42, a spot AF switch 43, and a drive switch 45 are provided around the CD display portion 23, and a macro switch 46 is provided behind the release button 20. The date switch 42 is used for the external LCD display unit 23.
Switch for changing the date display pattern, changing the imprinting pattern, and changing the date correction mode.
The date correction mode can be entered by pressing the date switch 42 for 3 seconds.

Next, a control system for executing various controls in the camera 11 will be described with reference to FIG.

A CPU 50 mounted on the camera 11 controls the operation relating to photographing in a centralized manner, and a RAM.
Each control operation is executed according to the program stored in 83.

The CPU 50 has a zoom motor drive circuit 5 for driving a zoom motor 51 for driving the taking lens 13.
3. A film motor drive circuit 54 for driving the film motor 52 for winding and rewinding the film, and a lamp drive circuit 55 for driving (lighting, blinking, and extinguishing) the red lamp 12a, the green lamp 12b, and the self lamp 12c are connected. ing. The red lamp 12a indicates whether or not strobe light emission is possible, and the green lamp 12b indicates whether or not AF is possible, both of which are provided near the viewfinder field. CPU5
0 also has an external LCD display section 23 for performing various displays,
Focus frame Fa, Fb,
Finder LCD display section 57 for displaying Fc, Fd, fa, fb, fc, fd (see FIG. 10), strobe circuit 58 for driving strobe light emitting section 19, passive AF module 18, AF auxiliary light projecting section 16, metering window 1
5 is connected to a photometric circuit 62 that calculates a photometric value based on the light received from Cds or the like inside 5 and a temperature detection circuit 63 that detects the temperature around the camera based on a signal from a sensor such as a thermistor.

The CPU 50 further includes a back cover switch 6
4, main switch 65, tele switch 66, wide switch 67, panorama switch 68, mode switch 4
1, a flash switch 40, a date switch 42, a drive switch 45, a spot AF switch 43, a photometric switch 74, a release switch 75, and a macro switch 46 are connected. The mode switch 41 is
It is a setting means for setting various modes related to photographing, and functions as a distance measurement mode setting means for setting, for example, a spot distance measurement mode and a multi distance measurement mode described later. The photometric switch 74 is turned on when the release button 20 is half pressed,
The release switch 75 is configured to be turned on when the release button 20 is fully pressed. The CPU 50 also turns on the DX information reading unit 77 that reads ISO information from the film cartridge, the lens information reading unit 78 that reads zoom information of the taking lens 13, and the 7-segment 80 of the external LCD display unit 23 based on the operation of the date switch 42. , Date LED driver circuit 7 that turns off the light and displays information
9. Film running detection circuit 8 for detecting film running
1, E ² PROM 82, RAM 83, and ROM 84 are connected.

The passive AF mounted on the camera 11
As shown in FIG. 5, the module 18 includes a pair of AF lenses (imaging lenses) 25 and 26 arranged at a distance of a base line.
And a pair of line sensors 27 and 28 for forming subject images by the AF lenses 25 and 26, respectively. Each of the line sensors 27 and 28 has the same shape, and has a large number of light receiving elements arranged in a row in the lateral direction so as to have a size that faces the maximum angle of view of the taking lens 13. The signals read from the line sensors 27 and 28 are used as a small set signal for each of a plurality of different small light receiving regions that receive subject images within different angles of view.

Now, referring to FIG. 6, description will be given of distance measurement by a general external light triangulation method using a pair of left and right line sensors 27 'and 28' (so-called triangulation). In the figure, when the distance from the line sensors 27 'and 28' and the AF lenses 25 'and 26' corresponding to them to the subject P (subject distance) is Lx, the subject distance Lx is the base line length B and the light reception. The distance x between the parts, the focal length f of the AF lenses 25 'and 26', the AF lens 2 in the line sensor 27 '
Distance XL between the optical axis of 5'and the light receiving portion, line sensor 28 '
Distance XR between the optical axis of the AF lens 26 'and the light receiving section
Can be obtained as follows. That is, B: (XL + XR) = Lx: f Therefore, Lx = Bf / (XL + XR)

In the present embodiment, the line sensor 2
The position of the light receiving element group in the small light receiving region where the small set signals 7 and 28 are to be obtained is changed by the CPU 50 in accordance with the focal length region information read from the RAM 83. This focal length area information is used by the lens information reading unit 78 during zooming.
It is written in the RAM 83 based on the information from the. Also,
The position of the light receiving element group in the small light receiving region is RO as set position information in each of four stages (see FIGS. 9 and 11) during the spot AF process and the multi AF process.
It is stored in M84.

Specifically, the line sensor 27 (28)
Has 128 light receiving elements arranged in a line, and as shown in FIG. 8, a small light receiving area consisting of 36 light receiving elements in the central portion is defined as a central light receiving area (first light receiving area) C The 36 small light receiving regions are defined as the left light receiving region L and the right light receiving region R, and the small light receiving region in which the central light receiving region C and the left light receiving region L overlap with each other in a predetermined relationship is a light receiving region LC (second A small light receiving region in which the central light receiving region C and the right light receiving region R overlap with each other in a predetermined relationship is set as a light receiving region (third light receiving region) RC. Each of the light receiving regions LC and RC is also composed of 36 light receiving elements. Incidentally, the reason why the light receiving regions are overlapped in a predetermined relationship in this way is as follows. That is, unless the light receiving element forming the light receiving area is shared by a certain portion, for example, when the image contrast is located only at the boundary between the two light receiving areas, there is no contrast in each light receiving area. This is because it becomes impossible to detect distance information.

The light receiving regions C, LC, RC, L and R are
In other words, the light receiving element group from which the small set signal is to be taken out when necessary is specified from the 128 light receiving elements, and the light receiving areas C ′, L of the subject shown in FIG. 7 are specified.
They correspond to C ', RC', L'and R ', respectively.
In addition, the number of light receiving elements of the line sensor 27 (28) is actually set to more than 128 so that a slight margin is left and right.

In this embodiment, the left and right line sensors 2
Light-receiving regions C and L each having five spots 7 and 28
The distance measurement performed by selectively utilizing the light receiving regions C, LC, RC of C, RC, L, R is hereinafter referred to as spot distance measurement.
Further, distance measurement performed by selectively utilizing all the light receiving regions C, LC, RC, L, and R is hereinafter referred to as multi-distance measurement.

As shown in FIG. 5, the line sensor 2
A plurality of subject images relating to the same subject are projected onto the respective sensors 7 and 28 at different positions on the sensors 27 and 28 via the corresponding AF lenses 25 and 26. The received light amounts accumulated as electric charges in the line sensors 27 and 28 are sent to the CPU 50 as electric signals (small set signals) via the quantizing units 29 and 30 and the calculating unit 31, respectively.

When the spot distance measurement mode is selected, the CPU 50 focuses on a plurality of stages (in this embodiment, the wide end to the tele end are divided into four steps at a predetermined pitch) of the taking lens 13 read from the RAM 83. Based on the position data of the small light receiving area read from the ROM 84 according to the distance area, the corresponding one is selected from the light receiving area positions of (a), (b), (c) and (d) of FIG. That is, after changing the relative positions of the light-receiving regions LC and RC with respect to the central light-receiving region C as shown in (a), (b), (c) and (d) of FIG.
A small set signal (distance information) from each of the selected light receiving areas is received via the calculation unit 31, and distance measurement calculation is performed based on this small set signal.

Further, when the multi-distance measurement mode is selected, the CPU 50 reads from the ROM 84 according to the focal length regions of a plurality of stages (4 stages similar to that for spot distance measurement) read from the RAM 83. Based on the position data of the small light receiving region, (a), (b) of FIG.
Corresponding ones are selected from the light receiving area positions of (c) and (d). That is, the light receiving area LC with respect to the central light receiving area C,
The relative positions of RC, L and R are shown in FIGS.
After changing as shown in (c) and (d), a small set signal from each selected small light receiving area is received via the arithmetic unit 31,
Distance measurement is performed based on this small set signal.

When selecting a small light receiving area in the spot distance measurement and the multi distance measurement, the position of the light receiving element group in each small light receiving area changes, but the number of elements for each light receiving element group is 36.
It is an individual, and it always changes.

As shown in FIG. 11, the finder field 47
Includes a pair of focus frames fa, fb, fc corresponding to (a), (b), (c) and (d) of FIG. 9 at the time of spot distance measurement from the wide end to the tele end.
fd is provided. Also, this focus frame f
On the outside of d, (a) of FIG.
A pair of focus frames Fa, Fb, Fc, and Fd corresponding to (b), (c), and (d) are provided.

At the time of spot distance measurement, the focus frame is
Light receiving areas C, LC, R in the line sensors 27, 28
9A, 9B of FIG. 9 in association with zooming,
When changing in the order of (c) and (d), fa, fb, f
Lighting and extinction are repeated in the order of c and fd. Further, during multi-distance measurement, in the focus frame, when the light receiving areas of the line sensors 27 and 28 change in the order of (a), (b), (c), and (d) of FIG. 10 due to zooming,
Fa, Fb, Fc, and Fd are sequentially turned on and off.
That is, in both spot distance measurement and multi-distance measurement,
The focus frame is widened on the tele side and narrowed on the wide side according to the changing focal length of the photographing lens 13. This compensates for the size deviation between the actual light receiving area and the focus frame, which cannot be eliminated only by switching the small light receiving area positions shown in FIGS. 9 and 10, and determines the size of the actual light receiving area at the current focal length. The photographer can feel it.

Next, the configuration of determining the sensor data from each light receiving area when distance measurement is performed using a plurality of light receiving areas, which is a feature of the present invention, will be described.

That is, the present camera 11 to which the present invention is applied.
Is a conventional problem that occurs when a large number of light receiving elements of a line sensor are used as one light receiving area, and a plurality of measurements based on sensor data from each light receiving area when the line sensor is divided into a plurality of small light receiving areas. It has a function to solve the conventional problems that occur when comparing distance values each time. In this embodiment, this function is configured to work only when the mode is switched to the spot distance measuring mode.

In order to realize such a function, in this embodiment, the CPU 50 is provided with a plurality of small light receiving regions C, LC, RC.
The function as a distance measuring calculation means for performing a distance measuring operation by each small set signal from the above and the reliability of each obtained distance measuring signal are determined by a plurality of small light receiving areas C, LC, R.
A function as a reliability determining means for determining C in a predetermined order, and a distance measuring signal from the small light receiving regions C, LC, RC that is initially determined to be reliable is determined as a distance measuring signal at that time. It has a function as a determining means. Further, the ROM 84 stores data programmed so that the CPU 50 determines the reliability of the distance measurement signal in the order of the central light receiving region C, the light receiving region LC, and the light receiving region RC. Details regarding these configurations will be described later with reference to the flowchart in FIG.

The above-mentioned function can be configured to work not only in the spot distance measuring mode but also in the multi distance measuring mode.

Next, the operation sequence of the camera having the above circuit configuration will be described with reference to the flow charts shown in FIGS. The operation is executed by the CPU 50 according to the program stored in the ROM 84.

First, when the main switch 65 is turned on and power is supplied to each circuit, the main routine shown in FIG. 12 is entered. In this main routine, first, information from each switch such as the photometric switch 74 is input (step S1). Then, the on / off of the back cover switch 64 is checked (S2). If the switch 64 is off, it is determined that the back cover 22 is closed and the process proceeds to S3. If the switch 64 is on, the back cover switch 64 is turned on. When it is determined that 22 is open, the process proceeds to S4. In S4, it is checked whether or not the loading is completed. If the loading is completed, the process proceeds to S3, and if not, the "loading process" subroutine is entered and the film loading is executed.

In S3, it is checked based on the zoom information from the lens information reading section 78 whether or not the taking lens 13 is in the lens storage position. If the taking lens 13 is in the storage position, the process proceeds to S7, and otherwise. If so, proceed to S6. In S7, it is checked whether or not the main switch 65 is turned on from off, and if it is turned on from off, it is determined that the camera 11 is in the initial movement, and the subroutine starting with the label of "lens wide movement processing" is entered to take a picture. The lens 13 is driven to the wide end, that is, the shooting start position. Also, the main switch 6
When 5 is turned off, the subroutine starts with the label "power down processing".

In S6, it is checked whether or not the main switch 65 is turned on, and if it is turned on, it is determined that the camera 11 is in the initial operation, and the date correction is canceled. That is, when the date switch 42 is held down for 3 seconds to enter the date correction mode (during date correction), the date correction is interrupted (released), and the corrected date is displayed on the external LCD display unit 23. If the date is not being corrected, the date is displayed with the date being canceled (as it is). After that, the subroutine starting with the label "lens storage processing" is entered (S1.
1, S12). If the main switch 65 is not turned on from the off state, it is checked whether the tele switch 66 is turned on or off by operating the zooming lever 21 (S10). As a result, if the tele switch 66 is turned on, the date switch 42 is further pressed for 3 seconds to check whether it is in the date correction mode (date correction) (S14). If not, S13. Proceed to.

If the date is being corrected in S14,
A subroutine starting with the label “correction addition processing” for adding the correction contents is entered, and otherwise, based on the zoom information from the lens information reading unit 78, the taking lens 13
Is checked at the tele end (S15). The "correction addition process" is for correcting the date display by adding the correction points set in the "date correction position change process" of S52 when the date is being corrected when the tele switch 66 is turned on. It is a subroutine.

If the taking lens 13 is at the telephoto end in S15, it is further checked whether the wide switch 67 is on or off (S13).
If 3 is not at the tele end, it is further checked based on the zoom information from the lens information reading unit 78 whether or not the taking lens 13 is in the macro position (S17). If it is in the macro position, the subroutine starting with the label "Tele end movement" is entered to move the taking lens 13 from the macro position toward the tele end, and if it is not in the macro position, "Tele zoom processing".
Enter the subroutine that starts with the label No. 13
Move from outside the macro position toward the tele end.

In S13, it is checked whether the wide switch 67 is turned on or off by the operation of the zooming lever 21, and if it is turned on, it is further checked whether or not the date is being corrected (S20). Proceed to S26. In S20, if the date is being corrected, the subroutine starting with the label "correction subtraction process" is entered (S22), and if not, it is further checked whether or not the taking lens 13 is set to the wide end. As a result, if the taking lens 13 is set to the wide end, the process proceeds to S26, and if not, the process proceeds to S23. "Corrected addition process"
Is displayed on the external LCD display unit 23, for example, when the wide switch 67 is turned on.
It is a subroutine for correcting "3" of "3" into another "2" or the like.

In S23, it is checked whether or not the taking lens 13 is in the macro position. If the taking lens 13 is in the macro position, the subroutine starting with the label "move wide end" is entered and the taking lens 13 is directed from the macro position to the wide end. If it is not in the macro position, a subroutine starting with a label of "zoom wide processing" is entered to move the taking lens 13 from a position other than the macro position toward the wide end (S24,
S25). In S26, the on / off state of the macro switch 46 is checked, and if the switch 46 is turned on, it is further checked whether or not the taking lens 13 is in the macro position (S28). If the switch 46 is not turned on, S27 is selected.
Proceed to. In S28, if the taking lens 13 is in the macro position, the process proceeds to S27, and if not, "macro move"
Enter the subroutine that starts with the label No. 13
Is moved toward the macro position (S29).

In S27, it is checked whether or not the drive switch 45 is turned on from off, and if it is turned on from off, the process proceeds to S31, and if not, the process proceeds to S30. S3
In step 1, it is checked whether or not the date is being corrected. If the date is being corrected, the process returns. If not, the subroutine starting with the label "drive setting process" is entered (S3
2). After exiting this subroutine, it is checked whether the drive switch 45 is on or off. If the switch 45 is turned off, the process returns. If it is turned on, it is checked whether the timer has timed up to a predetermined time of 3 seconds. As a result, if the time is up, the process proceeds to S35 to check the ON / OFF of the release switch 75, and if not, S33 is repeated. If the release switch 75 is turned on in S35, "lens wide movement processing" is performed.
Enter the subroutine beginning with the label of, and further enter the subroutine beginning with the label of "rewinding process" to rewind the film.

In S30, it is checked whether or not the mode switch 41 is turned on from off. If it is turned on from off, the process proceeds to S38, and if not, the process proceeds to S40. S38
Then, it is checked whether or not the date is being corrected. If the date is being corrected, the process returns. If not, the subroutine starts with the label of "mode setting process" (S39).
In this "mode setting process" subroutine, for example, among the light receiving areas C, LC, RC, L, R, the light receiving areas C, L
A spot distance measurement mode that is selectively used by using C and RC and a multi distance measurement mode that is selectively used by using all of the light receiving regions C, LC, RC, L, and R are set. Also S
At 40, it is checked whether or not the strobe switch 40 is turned on from off, and if it is turned on from off, the process proceeds to S42, and if not, the process proceeds to S41.

In S42, it is checked whether or not the date is being corrected. If the date is being corrected, the process returns. If not, the process proceeds to S43. In S43, it is checked whether or not the strobe non-light emission mode is set by the mode switch 41, and if it is set, the process returns. If not, the process returns to S43.
Proceeding to 44, the pre-flash setting is reversed.

While the date is being corrected, when the date display on the external LCD display unit 23 is displayed as, for example, 95_2_3, the date switch 42 is turned on to turn the correction position to "3", for example. Tele switch 6
By turning 6 on, this “3” can be corrected to “4”. In this case, first, it is checked whether or not the date switch 42 is turned on from OFF, and whether or not the date is being corrected. If the date is being corrected, "correction position changing process" is performed.
If it is not, the subroutine for setting the date is executed, and the subroutine for starting the label of "date display processing" is entered (S41,
S46-S48). After exiting from the "date display process" subroutine, check whether the date switch 42 is on or off. If the switch 42 is turned off, the process returns. If it is turned on, the timer has timed up to a predetermined time of 3 seconds. It is checked whether or not (S49, S50). If the 3-second timer is timed up, an initial set relating to date correction is executed and the process returns, and if not timed out, S49 is repeated.

In S45, it is checked whether the photometric switch 74 has been turned on from off. If it is turned on from off, the process proceeds to S54. If not, the process proceeds to S53. In S54, it is checked whether there is an error in loading,
If there is an error, the process proceeds to S53, and if not, it is checked whether or not the rewinding is completed (S55). And
If the rewinding is completed, the process proceeds to S53. If not, the subroutine starting with the label of "imaging process" is entered, and after exiting this subroutine, the process proceeds to S53 (S5).
6).

In S53, it is checked whether or not there is a strobe charging request, and if there is a request, the subroutine starts with the label "strobe charging process". If not, the subroutine starts with the label "power down process". Enter (S57, S58).

Next, the "photographing process" subroutine shown in step S56 will be described with reference to FIGS. When this subroutine is entered, first, ISO etc. is read from the loaded film putt through the DX information reading unit 77, the amount of charge in the battery is checked, and it is checked whether or not there is NG (S60-). S6
2). Then, if there is NG, the process returns, and if not, the subroutine starts with the label of "distance measurement" (S6).
3). After exiting this subroutine, the photometric circuit 6
The photometric calculation according to 2 is executed, and the AE calculation regarding the automatic exposure is executed (S64, S65).

In S67, it is checked whether or not the distance measurement value that can be used for photographing has been calculated (whether or not there is an error in the distance measurement calculation). If the distance measurement value does not exist (there is an error), the green lamp 12b. Blinks to inform the photographer that focusing is impossible (S71). If there is a distance measurement value (no error), it is determined whether or not the value is so close that focusing cannot be performed. Check further. As a result, if the subject is in such a short distance that the subject cannot be focused, the green lamp 12b is made to blink to inform the photographer to that effect (S71), and if not, the green lamp 12b is lit to inform the photographer. Notify that focusing is possible (S69).

In S70, it is checked whether or not the strobe is to be fired. If it is determined that the strobe is to be fired, FM calculation for calculating the amount of light emission and the like is executed, and then it is checked whether or not the strobe charge is OK. (S72, S73). If the charging is OK, the red lamp 12a is turned on via the lamp drive circuit 55 (S75), and if not, the red lamp 12a is blinked (S74).

In step S76, the subroutine starting with the label "switch input" is entered to input data of various switches, and then in step S77, it is checked whether the release switch 75 is on or off. And release switch 7
If 5 is turned on, the process proceeds to S78, and if not, S79.
Proceed to. In S79, it is checked whether the photometric switch 74 is on or off. If the photometric switch 74 is turned on, the process returns to S76 to repeat the "switch input" subroutine and the on / off check of the release switch 75, and turn off the red lamp 12a and the green lamp 12b which are otherwise lit or blinking.

In S78, it is checked whether or not the drive switch 45 has set the self mode, and if it is set, the "subroutine starting with the label of the self wait process is entered (S81), otherwise the process returns. "Self-wait processing" is a subroutine for releasing the shutter a few seconds after the release button 20 is pressed during self-timer shooting. "Self-wait processing"
After exiting the subroutine, in S82, it is checked whether or not the time waiting by the self-timer photographing is interrupted, and if it is interrupted, the process returns, otherwise the process proceeds to S83.

In S83, the self lamp 12c is turned on and the green lamp 12b and the red lamp 12a are turned off. Then, the photographing lens 13 is driven to a desired position, the self lamp 12c is turned off, a shutter mechanism (not shown) is driven to perform exposure, and the film after photographing is wound up one frame (S84 to S87). Here, it is checked whether or not the rewind is automatically set, and if it is automatically set, the rewind is executed (S88, S89), and if not, the process returns.

Next, the "distance measuring" subroutine shown in step S63 will be described with reference to FIG. First, the CPU 50 inputs the detection sensor data from the passive AF module 18, and checks whether or not the distance measuring mode to be executed is the multi distance measuring (S90, S9).
2). As a result, if multi-distance measurement is to be performed, a subroutine starting with the label "multi-AF processing" is entered (S
94), otherwise proceed to S93.

In S93, it is checked whether or not the distance measurement form to be executed is spot distance measurement. If spot distance measurement is to be performed, a subroutine starting with the label "Spot AF processing" is entered (S95), If not, the process proceeds to S96 to enter a subroutine starting with the label of "macro AF process".

Next, in step S95, "Spot A"
The "F process" subroutine will be described with reference to Fig. 18 and Fig. 19. In this subroutine, when the spot distance measurement mode is selected by the operation of the mode switch 41 in S39, the sensor start NO. DIV 0 to DIV 3 And ROM8
4. Reliability of the ranging signal obtained based on the small set signal from each of the light receiving regions C, LC, RC determined based on the data relating to the position of the small light receiving region corresponding to the focal length region stored in table 4 Gender (default (ranging N
G (that is, presence or absence of distance measurement impossible state)) is determined in a predetermined order for a plurality of small light receiving regions C, LC, and RC, and a small light receiving region first determined to be reliable (no default) This is for determining the distance measurement signal (distance measurement value) as the distance measurement signal at that time. As described above, in the present embodiment, in the case of the spot AF process, only the three small light receiving regions C, LC, RC located in the center of the screen and in the vicinity thereof are the targets of the reliability determination. The sensor start NO. “DIV0 to DIV3”, which is the focal length area information indicating the positions of the light receiving areas C, LC, and RC during the spot AF processing, is R based on the information from the lens information reading unit 78 during the zoom processing.
Written to AM83.

When this subroutine is entered, the CPU 50 first reads the sensor start NO. Of the light receiving area from the RAM 83 and checks whether or not this is DIV 0 ((a) in FIG. 9) (S130). And sensor start NO.
If it is judged to be DIV 0, this sensor start NO.
Information on DIV 0 R C_DIV 0, LC_DIV 0, RC_DIV 0
It is read from the OM 84 (S131).

Further, information C_DIV 0, LC_DIV 0, RC_DIV
Based on 0, the position of each light receiving area is determined as follows (S
132). That is, the central light receiving area C is set to C_DIV 0 to C_DIV.
0 + N-1 (N is the prescribed number of light receiving elements in each light receiving region C, LC, RC (36 in this embodiment)), and the light receiving region LC
Be LC_DIV0 to LC_DIV0 + N-1, and the light receiving region RC is
It is defined as RC_DIV0 to RC_DIV0 + N-1.

Thereafter, the arithmetic unit 31 of the passive AF module 18 sequentially sends the sensor data from the light receiving elements located in each of the determined light receiving areas to the CPU 50 based on the signal of the CPU 50. For example, in FIG. 9, when the CPU 50 requires the right light receiving region R from the ninth sensor data from the right of the 128 light receiving elements, it receives the signals 9 to 9 + N-1 related to the sensor start NO. From the CPU 50. The calculation unit 31 sequentially transmits the 9th to 9 + 35th (that is, 44th) sensor data to the CPU 50. And the CPU 50
In the subroutine of "default determination processing for each area" in S96, the presence or absence of default in each area is determined based on the sensor data (S133).

In S130, the sensor start N
If it is determined that O. is not DIV 0, the flow advances to S134 to check whether the sensor start NO. Is DIV 1 ((b) in FIG. 9). Then, if it is determined that it is DIV 1, information about sensor start NO. DIV 1 C_DIV 1, LC_DIV
1. Read RC_DIV1 from ROM 84 (S135).

Information C_DIV 1, LC_DIV 1, RC_DIV
Based on 1, the position of each light receiving area is determined as follows. That is, the central light receiving area C is C_DIV1 to C_DIV1 + N-1, and the light receiving area LC is LC_DIV1 to LC_DIV1 + N-1.
The light receiving regions RC are defined as RC_DIV1 to RC_DIV1 + N-1 (S136), and the "each region default determination process" subroutine is entered (S133).

In S134, the sensor start NO. Is DI
If it is judged that it is not V 1, the sensor start NO.
Checks whether it is DIV 2 ((c) in FIG. 9) (S137). And if it is judged to be DIV 2, RO
The information C_DIV 2, LC_DIV 2, RC_DIV 2 regarding the sensor start NO. DIV 2 stored in M84 is read (S13).
8).

Then, similarly to the above, the position of each light receiving region is determined as follows. That is, the central light receiving area C is
C-DIV 2+ N-1 and the light receiving area LC is LC_DIV2-LC_D
IV2 + N-1 and the light receiving area RC is RC_DIV2 to RC_DIV2
It is determined to be + N-1 (S139), and the subroutine of "each area default determination processing" is entered (S133).

In S137, the sensor start N
If it is judged that O. is not DIV 2, sensor start NO. D
Information on IV 3 ((d) in Fig. 9) C_DIV 3, LC_DIV
3. Read RC_DIV3 from ROM 84 (S140).

Then, the position of each light receiving area is determined as follows. That is, the central light receiving area C is set to C_DIV 3 to C_DIV 3+
N-1 and the light receiving area LC is LC_DIV3 to LC_DIV3 + N-1
Then, the light receiving area RC is defined as RC_DIV3 to RC_DIV3 + N-1 (S141), and the "each area default determination processing" subroutine is entered (S133).

In this "each area default judgment processing",
It is determined whether or not there is a default (distance measurement impossible state) in the light receiving region selected corresponding to the focal length region of the taking lens 13. Based on this determination, for example, a flag is set in a region having no default among the selected small light receiving regions. After this processing, the subroutine starting with the label "each area distance measurement calculation processing" is entered, and the distance measurement value in each light receiving area is calculated (S142). During this calculation, the central light receiving area C
CX, the distance measurement value of the light receiving area LC is LCX, and the distance measurement value of the light receiving area RC is RCX. The greater the distance measurement values are, the closer the subject is to the near side.

First, in S143, "0" is set to the reference distance measurement value X. Then, it is checked whether or not there is a default in each of the small light receiving regions C, LC, RC while looking at the flag set in S133. As a result, if there is no default in the central light receiving area C, the distance measurement value CX in the central light receiving area C is put into X as the distance measurement value used for the focusing operation (S145).

On the other hand, when it is determined that the central light receiving area C has a default, the CPU 50 further causes the light receiving area L
It is checked whether or not both C and RC have defaults (S146). As a result, if there is a default in both the light receiving areas LC and RC, it is determined that there is no distance measurement value and the processing returns to the "imaging processing" subroutine (S147). After it is determined in S67 that there is a distance measurement error, the green lamp 12b is turned on in S71. Flashes to inform the photographer that focusing is not possible.

If it is determined in S146 that neither the light receiving areas LC and RC have defaults, it is further checked whether or not both light receiving areas LC and RC have defaults. If there is no default in both the light receiving areas LC and RC, the distance measurement value LCX is set to the distance measurement value X.
Then, the distance measurement value X is compared with the distance measurement value RCX. As a result, if the distance measurement value RCX is larger than the distance measurement value X, the distance measurement value RCX is set as the closer distance side value.
Put it in and use it for focusing. If the distance measurement value RCX is not larger than the distance measurement value X, the distance measurement value X including the distance measurement value LCX is used as it is as the value for focusing.

On the other hand, in S148, the light receiving region L
If it is determined that both C and RC do not have defaults, it is first checked whether or not there is a default in the light receiving area LC, and if there is no default in this light receiving area LC, the distance measurement value LCX is given priority. Adopted (S152, S
153). If the light receiving area LC has a default, the distance measurement value RCX having no default is adopted (S154).

As described above, the CPU 50 sequentially checks each of the light receiving areas C, LC and RC to be used in the spot distance measurement, and when the light receiving area C first has an appropriate value (reliable value), this is checked. Adopt the value as the value used for focusing,
If an appropriate value does not appear in the light receiving area C, the light receiving area L
Check if there are defaults in C and RC. In this case, when there is a default in at least one of the light receiving areas LC and RC, it is first checked whether or not the distance measurement value of the light receiving area LC has a default. Then, when there is no default, the distance measurement value of the light receiving area LC is adopted, and when there is a default, the distance measurement value of the light receiving area RC is adopted, thereby selecting an appropriate distance measurement value that is not the default. Further, the light receiving area C has a default, and the light receiving area LC,
If there is no default in both RC, the larger one of the distance measurement values LCX, RCX in these light receiving regions LC, RC is adopted as the value for focusing.

As described above, according to the present automatic focus detection device, during spot distance measurement, the order of determination of reliability of the distance measurement value (distance measurement signal) (priority of determination) is the central light receiving area C,
Since the light receiving area LC and the light receiving area RC are set in this order (however, the light receiving areas LC and RC are prioritized only when one of them has a default), an error occurs in the distance measurement in the central light receiving area C. However, the distance measurement values of the next light receiving regions LC and RC can be promptly adopted. Therefore, it is possible to eliminate the unfocusable state as much as possible to increase the focusing rate, and it is possible to greatly reduce the inconveniences such as missing a photo opportunity due to being unable to focus, and further shortening the time required for distance measurement calculation. Therefore, it is possible to provide a speedy shooting operation.

Next, in step S94, "Multi AF
20 will be described with reference to FIGS. 20 and 21. Corresponding to the zooming position of the taking lens 13,
Sensor start NO. "DIV0 to DIV3" indicating the position of each light receiving area C, LC, RC, L, R (focal length area information)
Is written in the RAM 83 based on information from the lens information reading unit 78 during zoom processing in S10, S13, S26 and the like.

The "multi-AF processing" subroutine is S3.
When the multi-distance measurement mode is selected by operating the mode switch 41 in 9, sensor start NO. DIV 0 to DI
Each of the light receiving regions C, LC, RC determined based on V 3 and the data regarding the position of the small light receiving region corresponding to the focal length region, which is stored as table data in the ROM 84.
The reliability of the distance measurement value (whether or not there is a default) is determined for each of L and R, and of the distance measurement values in the reliable (non-default) light receiving area, the value at the shortest distance side within the focusable range. For determining the distance measurement value. When this subroutine is entered, first, in S90, the sensor start number of the light receiving area is read from the RAM 83, and this is the DIV.
It is checked whether it is 0 ((a) in FIG. 10). When the CPU 50 determines that the sensor start NO. Is DIV 0, the CPU 50 stores the sensor start N stored in the ROM 84.
O. Information about DIV 0 C_DIV 0, LC_DIV 0, RC_DIV
0, L_DIV 0, and R_DIV 0 are read (S102).

Then, in S103, the above information C_DIV
Based on 0, LC_DIV0, RC_DIV0, L_DIV0, R_DIV0, the position of each light receiving area is determined as follows. That is, the central light receiving area C is set to C_DIV0 to C_DIV0 + N-1 (N is the prescribed number of light receiving elements in each light receiving area C, LC, RC, L, R (36 in this embodiment)), light receiving area LC To LC_DIV0
~ LC_DIV0 + N-1 and set the light receiving area RC to RC_DIV0 to RC
_DIV0 + N-1 and the left light receiving area L is L_DIV0 to L_DIV
0 + N-1 and the right light receiving area R is R_DIV 0 to R_DIV 0+
Defined as N-1.

The arithmetic unit 31 of the passive AF module 18
On the basis of the signal from the CPU 50, based on the signal from the CPU 50, the sensor data from the light receiving element located in each of the light receiving regions thus determined is added to the CP data.
Send to U50 in order. The transmission of the sensor data to the CPU 50 is performed in the same manner as the above-described spot distance measurement.

In S90, the sensor start NO. Is DI
If it is determined that it is not V 0, the flow advances to S91 to check whether the sensor start NO. Is DIV 1 ((b) in FIG. 10). If it is determined to be DIV 1, ROM84
Information about sensor start NO. DIV 1 stored in C_
DIV 1, LC_DIV 1, RC_DIV 1, L_DIV 1, and R_DIV 1 are read (S104).

Then, in S105, the information C_DIV 1,
Based on LC_DIV1, RC_DIV1, L_DIV1, and R_DIV1, the position of each light receiving area is determined as follows. That is, the central light receiving area C is set to C_DIV 1 to C_DIV 1+ N-1, and the light receiving area LC
Be LC_DIV1 to LC_DIV1 + N-1, and the light receiving region RC is
RC_DIV1 to RC_DIV1 + N-1 and set the left light receiving area L to L_DI
V 1 to L_DIV 1+ N-1 and set the right light receiving area R to R_DIV 1
~ R_DIV 1 + N-1 is set, and the subroutine of "each area default judgment processing" of S96 is entered.

In S91, the sensor start NO. Is DI
If it is determined that it is not V 1, the process proceeds to S93, and it is checked whether or not the sensor start NO. Is DIV 2 ((c) in FIG. 10). If it is determined to be DIV 2, ROM 84
Information about sensor start NO. DIV 2 stored in C_
DIV 2, LC_DIV 2, RC_DIV 2, L_DIV 2 and R_DIV 2 are read (S 106).

Then, in S107, the positions of the respective light receiving regions are determined as follows, as described above. That is, the central light receiving area C is set to C-DIV 2 to C-DIV 2+ N-1, and the light receiving area LC
Be LC_DIV2 to LC_DIV2 + N-1, and the light receiving region RC is
RC_DIV2 to RC_DIV2 + N-1 and set the left light receiving area L to L_DI
V 2 to L_DIV 2+ N-1 and set the right light receiving area R to R_DIV 2
~ R_DIV 2 + N-1 is set, and the subroutine of "each area default judgment processing" of S96 is entered.

In S93, the sensor start NO. Is DI
If it is judged that it is not V 2, the information C_ regarding the sensor start NO. DIV 3 ((d) in FIG. 10) stored in the ROM 84.
DIV3, LC_DIV3, RC_DIV3, L_DIV3, and R_DIV3 are read (S94).

Then, in S95, the position of each light receiving area is determined as follows. That is, the central light receiving area C is changed to C_DIV
3 to C_DIV 3+ N-1 and the light receiving region LC is LC_DIV 3 to
LC_DIV3 + N-1 and the light receiving area RC is RC_DIV3 to RC_D
IV3 + N-1 and the left light receiving area L is L_DIV 3 to L_DIV 3
+ N-1 and the right light receiving area R is R_DIV 3 to R_DIV 3 + N-1
Then, the subroutine of "each area default judgment processing" of S96 is entered.

In S96, it is determined whether or not there is a default in the light receiving area selected corresponding to the focal length of the taking lens 13. Based on this determination, for example, a flag is set in a region having no default among the selected small light receiving regions. After this processing, the subroutine starting with the label "each area distance calculation processing" is entered (S97), and the distance measurement value in each light receiving area is calculated. In this calculation, the distance measurement value of the central light receiving area C is CX, the distance measurement value of the light receiving area LC is LCX, the distance measurement value of the light receiving area RC is RCX, the distance measurement value of the left light receiving area L is LX, and the right light receiving area R is The measured distance value of is RX. The greater the distance measurement values are, the closer the subject is to the near side.

First, in S98, "0" is set to the reference distance measurement value X. Then, the presence or absence of a default in each small light receiving area C, LC, RC, L, R is checked while looking at the flag set in S96, and the distance measurement value in the small light receiving area without default is compared with the distance measurement value X. Then, if it is larger than the distance measurement value X, the value is put into the distance measurement value X,
The distance measurement value X is further compared with the distance measurement values in other non-default small light receiving areas (S100, S101, S1).
08-S119). Then, in S67 of the main routine, it is determined whether or not the value finally obtained as the distance measurement value X has an error (whether it is smaller than 0). If it is smaller than 0, the distance measurement value is The green lamp 12b is flashed as a non-existence (that is, unfocusable) to notify the photographer of the fact (S71), and if it is greater than 0, it is checked whether the value indicates a short distance beyond which focusing is impossible. . As a result, if the value indicates a short distance that cannot be focused, the green lamp 12b is blinked (S71), and if not, the green lamp 12b is lit to notify the photographer that focusing is possible. (S69).

In this embodiment, the zoom lens (photographing lens 13) is used as the photographing optical system having a variable focal length, but a multifocal lens can be used instead of the zoom lens. In that case, the position of the light receiving element group in the small light receiving region where the small set signals of the line sensors 27 and 28 are to be obtained is
The multifocal lens can be set corresponding to each focal length that can be switched.

[0082]

As described above, according to the present invention, it is possible to select a reliable signal from a plurality of distance measurement signals in a predetermined order. It is possible to increase the focusing rate without it, and to greatly reduce the inconvenience of missing a photo opportunity such as being unable to focus, and also to shorten the time required for distance measurement calculation and provide speedy shooting operation. Becomes

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a camera to which the present invention is applied.

FIG. 2 is a rear view of the camera.

FIG. 3 is a plan view of the camera.

FIG. 4 is a system block diagram showing a control system of the present embodiment.

FIG. 5 is a schematic view showing a structure of a passive AF module of the same embodiment.

FIG. 6 is a schematic diagram for explaining distance measurement by a general external light triangle method using a pair of line sensors.

FIG. 7 is a schematic view showing the structure of a passive AF module of this embodiment.

FIG. 8 is a diagram showing a small light receiving area set in a line sensor used in the passive AF module.

FIG. 9 is a diagram showing the positions of the small light-receiving regions of the line sensor during spot distance measurement, which correspond to the focal length regions of the photographing lens divided into a plurality of stages.

FIG. 10 is a diagram showing the positions of the small light-receiving areas of the line sensor during multi-distance measurement, which correspond to the focal length areas of the photographing lens divided into a plurality of stages.

FIG. 11 is a diagram showing a focus frame whose range changes according to a change in the focal length of the taking lens.

FIG. 12 is a flowchart showing main processing in the present embodiment.

FIG. 13 is a flowchart showing a main process in the embodiment.

FIG. 14 is a flowchart showing a main process in the embodiment.

FIG. 15 is a flowchart showing a subroutine relating to shooting processing in the embodiment.

FIG. 16 is a flowchart showing a subroutine relating to shooting processing in the embodiment.

FIG. 17 is a flowchart showing a subroutine relating to distance measurement in the embodiment.

FIG. 18 is a flowchart showing a subroutine relating to spot AF processing in the embodiment.

FIG. 19 is a flowchart showing a subroutine relating to spot AF processing in the embodiment.

FIG. 20 is a flowchart showing a subroutine relating to multi-AF processing in the same embodiment.

FIG. 21 is a flowchart showing a subroutine relating to multi-AF processing in the embodiment.

[Explanation of symbols]

11 camera 13 shooting lens (shooting optical system) 18 passive AF module (focus detection system) 25 26 AF lens (imaging lens) 27 28 line sensor 29 30 quantizer 31 arithmetic unit 41 mode switch (distance measurement mode setting means) 50 CPU (distance measurement calculation means, reliability judgment means, determination means) 83 RAM 84 ROM C central light receiving area (first light receiving area) LC light receiving area (second light receiving area) RC light receiving area (third light receiving area) )

Claims (6)

[Claims] 1. An imaging optical system having a variable focal length; and a pair of imaging lenses having optical axes that do not coincide with the optical axis of the imaging optical system and arranged apart from each other by a baseline length, and each imaging lens. A focus detection system including a pair of line sensors on which a subject image is formed by each line sensor, each line sensor having a size that faces a maximum angle of view of the photographing optical system, and a signal from the line sensor In an automatic focus detection device for a camera used as a small set signal for each of a plurality of different small light receiving areas, which receives an object image within a different angle of view, the distance measurement calculation is performed using the small set signals from the plurality of small light receiving areas. A distance measurement calculation means for obtaining a distance measurement signal by performing
Reliability determining means for determining the reliability of each distance measuring signal by the distance measuring calculation means in a predetermined order for the plurality of small light receiving areas; this reliability determining means is first judged to be reliable. An automatic focus detection device for a camera, comprising: a determining unit that determines a distance measurement signal from a small light receiving area as a distance measurement signal at that time. 2. The plurality of small light receiving regions according to claim 1, wherein the first light receiving region is located substantially in the center of the line sensor, and the first light receiving region partially overlaps with the first light receiving region. An automatic focus detection device for a camera having second and third light receiving regions located on both sides of the light receiving region. 3. The reliability determination means according to claim 2, wherein the reliability of the distance measurement signal from the first light receiving area is first determined, and then the distance measurement signal from the second and third light receiving areas is determined. Automatic focus detection device for cameras to judge the reliability of the camera. 4. The method according to claim 2, wherein both sides of the first light receiving region partially overlap with each of the second and third light receiving regions and do not overlap with the first light receiving region. An automatic focus detection device for a camera further including fourth and fifth light receiving regions. 5. The spot distance measuring mode according to claim 4, wherein the first to third light receiving areas are selectively utilized among the first to fifth light receiving areas, and the first to fifth light receiving areas. An automatic focus detection device for a camera, further comprising distance measurement mode setting means for setting a multi-distance measurement mode performed by selectively utilizing all of the above. 6. The reliability determining means and the determining means according to claim 5, when the spot distance measuring mode is set by the distance measuring mode setting means, the distance measuring signals based on the first to third light receiving regions are detected. When the reliability is determined in a predetermined order and the first reliability is determined as the ranging signal, when the multi-ranging mode is set,
An automatic focus detection device for a camera, which determines the reliability of a distance measurement value for each of the fifth light-receiving areas and determines the closest one of the reliable values as a distance measurement signal.