JPS63172216A - Automatic focus detector - Google Patents

Abstract

PURPOSE:To execute accurate focus detection by executing the temperature compensation of a defocused value obtained from an interval between images on an image pickup element array in accordance with an interval between lenses in an image reformation lens body corresponding to each image pickup element array. CONSTITUTION:The lens interval Dd2 between at least a pair of image reforming lenses d2 is different from lens intervals Dd1, Dd3 of other pairs of image reforming lenses d1, d3 and changes in the lens intervals at the time of generating a change in temperature are different. A temperature compensating means 3 calculates the temperature compensating values DELTAepsilon1'-DELTAepsilon3' of defocused values in respective focus detecting means in accordance with a detecting temperature (t) based upon a temperature detecting means 2 and the lens intervals Dd1-Dd3 of respective pairs d1-d3 of image reforming lenses. Defocused values DELTAepsilon1-DELTAepsilon3 calculated by a 1st calculating means 1 are compensated at their temperature by a 2nd calculating means 4 based on the temperature compensating values DELTAepsilon1'-DELTAepsilon3'.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic focus detection device having a plurality of focus detection areas.

(Prior Art) Conventionally, as shown in FIG. 4(a), an image formed by a photographing lens a is captured by a pair of re-imaging lenses d1, which are arranged in a row of image sensors e, with first and second arrays above. A focus detection device is widely used that detects the focus adjustment state of the photographic lens a by detecting the interval between the first and second images using the image sensor array e1.

In such a focus detection device, in-focus occurs when the interval between the first and second images on the image sensor array e1 is a predetermined length, front focus occurs when the interval is shorter than the predetermined length, and rear focus occurs when the interval is longer than the predetermined length. The amount of deviation from the in-focus position is determined and output as a defocus amount. The distance Del between the first and second images on the image sensor array e1 changes in response to a change in the lens distance D d + of the re-imaging lens pair d1. Therefore, for example, when a plastic lens is used as the re-imaging lens pair d, the lens distance Dd+ changes due to temperature change, and the distance De+ between the first and second images on the image sensor array e1 changes. Therefore, the amount of defocus also changes. Therefore, it has been proposed to detect the temperature of the focus detection device and correct the defocus amount according to the detected temperature (see Japanese Patent Laid-Open No. 60-235110).
.

(Problems to be Solved by the Invention) As shown in Figure 5, there is a horizontally long focus detection area (A) in the center of the photographic screen, and vertically long focus detection areas (B) and (C) on both sides.
When performing automatic focus detection in three areas with
The above three focus detection areas (A) and (B).

CCD image sensor array e2 + "I corresponding to (C)
+e:l is constructed on one chip as shown in FIG. In this CCD chip, the length of the CCD image sensor array el, e3 corresponding to the focus detection area (B) or (C) on both sides of the screen is determined by the length of the focus detection area (A>
By making the length shorter than the length of the CCD image sensor array e2 corresponding to the CCD image sensor array e2, the focus detection module can be made smaller by this difference in length, and the time for data dump from the CCD image sensor array el+e:l can be shortened. It is thought that it can be done. For this purpose, as shown in FIG. 2, the lens distances Dd, , Dd of the re-imaging lens pairs d, , d3 on both sides are made shorter than the lens distance Dd2 of the central re-imaging lens pair d2. , correspondingly, the required CCD image sensor array el+e
It is sufficient to decide the number of elements of 3. However, if a temperature rise occurs in such a case, each re-imaging lens pair cll, d
2. Even if d3 is made of the same material, the amount of change in the image distance due to temperature rise will be different due to the difference in the lens distance. Also, each re-imaging lens pair cL, d2. d3
If they are not made of the same material, the thermal expansion coefficients are not the same, so the amount of change in the image interval due to temperature rise will also differ for each focus detection area.

The present invention has been made in view of these points, and an object of the present invention is to provide information on each focus detection area even if the lens spacing of the re-imaging lens pair is not the same for a plurality of focus detection areas. An object of the present invention is to provide an automatic focus detection device that enables temperature compensation of the amount of defocus.

<Means for Solving the Problems> In order to achieve the above object, in the automatic focus detection device according to the present invention, as shown in FIG.
The image formed by a pair of re-imaging lenses cl, ,
d2. Image sensor rows e+ and e arranged in a line by d3
2. e2 as the first and second images, and the image interval between the first and second images is set to the image sensor arrays el, e2, e.
, a plurality of focus detection units are provided to detect the focus adjustment state of the photographing lens a by detecting the focus adjustment state of the photographing lens a by detecting the output of the lens a, and the lens interval Dd2 of at least one pair of reimaging lenses d2 is different from that of the other reimaging lens pairs d, , d, lens spacing Dd,.

This is a focus detection device different from the Dd3, and as shown in FIG. Focus amount Δε1. Δε2゜Δ
A first calculation means (1) for calculating ε3, and a pair of re-imaging lenses cL, d2. temperature detection means (2) for detecting the temperature t in the vicinity of di; and the temperature t detected by the temperature detection means (2) and the lens distance Dd, , Dd2 of each re-imaging lens pair d, , d, , d3. ．． Temperature compensation amount Δε8°, Δε2 of defocus amount for each focus detection area according to Dd3
'.

Temperature compensating means (3) for calculating Δε3° and defocus amount Δε1. obtained by first calculation means (1). Δε2,
Δε3 and temperature compensation amount Δ obtained by temperature compensation means (3)
Temperature-compensated defocus amount Δε, +Δε,′, Δε2+Δε2′, Δε from ε1゛, Δε2′, Δε3°
3+Δε3'.

However, the symbols etc. in the above structure are described for explanation purposes and are not intended to limit the scope of the present invention.

(Function) In the present invention, at least one pair of re-imaging lenses d2
The lens distance Dd2 is another re-imaging lens pair d,.

The lens spacings D d + and D d d are different from each other, and the amount of change in the lens spacing when a temperature change occurs is different. The temperature t detected by the temperature detection means (1) and each re-imaging lens pair d+, d2. d3 lens spacing D d,
, D d2. D d.

The temperature compensation amount Δε,′, Δε2°, Δε,° of the defocus amount for each focus detection area is determined by the temperature compensation means (3
) is determined by The defocus amount ΔεhΔε2 calculated by the first calculation means (1). Δε3 is the second
In the calculation means (4), the temperature compensation amount Δε1°,
The temperature is compensated by Δε2'' and Δε3'.

Note that the temperature detected by the temperature detection means (2) is determined by each re-imaging lens pair d+, d2 . ds temperature 1. ．． Although it is convenient to detect only the temperature t at one location, considering that 12.13 are approximately the same, each re-imaging lens pair d, d2 . d
3 temperature 1. ．． 1. ．． 13 may be detected individually.

Furthermore, it goes without saying that the number of focus detection areas is not limited to three, and may be any number greater than or equal to two.

(Example) Examples of the present invention will be described below.

FIG. 2 is a perspective view showing a schematic configuration of an automatic focus detection device according to an embodiment of the present invention. In the figure, a is a photographing lens, and b is a focal plane. b' is a field stop arranged near the focal plane, and has a rectangular opening b1'.

b2", b3'. CI + (" 21
e3 is a condenser lens, d, , d2. d is a pair of re-imaging lenses, and el +62 +23 is a CCD image sensor array arranged at the focal plane of the re-imaging lens. f is an aperture mask and has an oval opening fl+f2. It has f+. The image whose field of view is limited by the rectangular aperture b"1 passes through the condenser lens c1 and is projected as two images onto the CCDCD image sensor array by the re-imaging lens pair d. Field stops b2' and b3 '' image is similarly formed by the condenser lens c2+03 and reimaging lens pair d2. The image is projected onto the CCD image sensor array e2+e3 by d3.

Here, the re-imaging lens pair cL, d2. Let the respective lens intervals of ds be Ddl, Dd2. Let it be Dcl. In this embodiment, all two CCDCD image sensor rows arranged in the X direction are
The length of the CCD image sensor array el+e3 arranged in the direction is set short, thereby reducing the area of the CCD image sensor array and the total 8 hours required for data output.

This will be explained with reference to FIGS. 3(a) and 3(b). C.C.
The D image sensor array is not only created in the required number (hatched area), but also created as a line including the white area that is not shaded. Therefore, for example, when the number of required elements is (number of e2)>(number of el), the interval between the re-imaging lens pair d, and the central CCDCD imaging element array 2 imaging lens pair d2 are If the spacing is the same, the CCDC image sensor array will look like the solid line in Figure 3(a),
Comparing the two upper rows of CCDCD image pickup elements in the center indicated by the dashed line, the number of useless COD pixels increases and the size also increases.

Furthermore, when inputting data, the portions shown in white must also be entered, so it takes a long time to input the data. However, in this case, since the image interval is the same as that of the upper two rows of CCDCD image pickup elements in the center, the amount of defocus per pitch for each region is the same, and no correction is necessary.

FIG. 3(b) shows a pair of re-imaging lenses d, in order to shorten the image interval.
The distance between the lenses is shortened, and as a result, C
OD waste is reduced and downsizing can be achieved. In addition, the input time for data input is also shortened. Furthermore, it is possible to downsize the imaging optical system. However, in this case, since the image interval for the same amount of defocus is different from that on the central CCDCD image sensor row, correction for this is required.

From the above, the re-imaging lens pairs d, d2. The distance between each lens of d3 is Dd2≧D d, = D d3, and C
It is desirable to design the basic image interval of the images formed on the CD image sensor array el+e'l to be short on the CCDC CD image sensor array 2, and to correct the image interval.

FIG. 4(a) shows the lens distance of the re-imaging lens pair d1 as Dd.
, and the interval between the images that are imaged one above the CCDCD image sensor array at the time of focusing is De.

FIG. 4(b) shows the lens distance of the re-imaging lens pair d2 as Dd.
2, and the interval between the two images on the CCDCD image sensor array at the time of focusing is De2. Similarly to Fig. 2, a is the imaging lens, b is the focal plane, d, , d2 are the re-imaging lens pair, and e+, e2 are C on the re-imaging lens focal plane.
This is a CD image sensor array, and this CCD image sensor array el+e
The image projected onto 2 is photoelectrically converted and used for focus detection.

In this way, when the lens distances Dd, , Dd2 of the re-imaging lens pair d, , , d2 are set separately, the values of the image distance increase/decrease ΔDel+ΔDe2 are different for the same amount of defocus. Furthermore, even when the pair of re-imaging lenses d1 and d3 are created with the same design so that D d+ = D d*, the actual values will vary due to work. Furthermore, the pitch interval of the CCD image sensor array itself may vary.

Therefore, it is desirable to set the distance measurement detection sensitivity (defocus amount per pitch) for each region.

Also, due to the temperature rise, these re-imaging lens pairs d3. d
2. Lens spacing of d3 D d + , D d 2 ,
D d :l varies, even if the reimaging lens vs. dl,
d2. Even if d3 is made of the same material with the same coefficient of thermal expansion, the lens distances D d + and D d 2 at room temperature
, D d3 are different, the change in lens spacing ΔDT(L, ΔDTd2.ΔDTd3) due to temperature rise is different, and the change in image spacing due to the change in lens spacing ΔDT(L, ΔDTd2.ΔDTd3 is different)
DTe + +ΔD7e2. The values of ΔDTe3 will be different. In particular, when a plastic lens is used, thermal expansion due to temperature becomes noticeable. Therefore,
It is desirable to set a temperature compensation coefficient for each region.

Furthermore, the optical system module and the CCD image sensor are adhesively bonded while adjusting their positions during the manufacturing process. On this occasion,
If an error occurs in the parallelism between the two, as shown in FIG. 4(c), even if the re-imaging lens pair d+ and d3 are manufactured in exactly the same way, the basic image distance Den will change.

A difference occurs in De3. In order to compensate for such differences,
It is desirable to set a different Z-axis adjustment amount for each focus detection area and each block.

FIG. 5 shows a viewfinder display of a camera using the focus detection device of this embodiment. In this example, three areas (A
), (B), and (C) can be subjected to focus detection. The rectangular frame indicated by the dotted line in the figure is displayed to show the photographer the area where focus detection is being performed. placed in position. The display of this focus detection area is based on automatic focus detection (hereinafter referred to as AF).
It is possible to switch between FA (Focus Aid) and only focus detection without lens drive (hereinafter referred to as FA (Focus Aid)).
A small frame is displayed during FA. The details will be described later. (L a) shown outside the shooting screen (S),
The display of (L 1]) and (L c> indicates the focus detection state; when in focus, it is (L +)), and when the front focus is (L
a), (Lc) lights up when the rear focus is achieved, and both (La) and (Lc) blink when the focus cannot be detected.

FIG. 6(a) shows the CCD used in this focus detection device.
The light receiving section (hereinafter referred to as a CCD including the light receiving section, storage section, and transfer section) is shown. Each area (A) in Figure 5,
For (B) and (C), a reference part and a reference part are respectively provided, and one side of each reference part in the longitudinal direction is used to control the integration time to the storage part of the CCD. Light receiving elements (MA), (MB), and (MC) for monitoring are provided. The number of pixels in the standard and reference parts of each area (A), (B), and (C) is (44, 52) in area (A),
(34°44) in region (B), <34 in region (C)
．． 44 >.

These are all formed on one chimp.

In the focus detection device of this embodiment, the reference portion of the CCD in the three regions described above is divided into a plurality of parts, and the divided reference part and all of the reference parts are compared to perform focus detection. In each area, among the focus detection results obtained by dividing, the data of the rearmost focus is used as the focus detection data of each area, so that the most recent subject from the camera is focused on the subject from focus 1, and then the data of the focus detection data of each area is Among them, the data of the rearmost focus is used as the camera's focus detection data.

The range to be divided and the defocus range of the divided area are shown in FIG. 7, FIG. 8, and FIG. 6 (1), and will be explained. FIG. 7 is an enlarged view of the focus detection area on the photographic screen shown in FIG. Focus detection area (A), (B
) and (C) are the areas of the reference portion shown in FIG. 6(a). In addition, in FIG. 7, the numerical values shown in each area indicate the number of differences obtained by taking the difference data of every third COD pixel shown in FIG. Alternatively, you may place one. However, in this case, the above values will be different.) Therefore, the number of reference parts and reference parts in each region (X.

Y) is (40,48) in area (A), (40, 48) in area (B), (
In C), it becomes (30, 40). As for the division in each area, in area (A) it is divided into three, starting from the leftmost difference data (1-20), (11-30), (21-40),
Let them be (A 1 ), (A 2 ), and (A 3 ), respectively. In areas (B) and (C), the difference data at the top end is (1
~20) and (11~30), respectively (B 1
), (B 2 ), (CI ), and (C2).

In this phase difference method focus detection, when the images of the reference part and the reference part match, when the image interval is larger than a predetermined number, the rear focus is on, and when it is smaller than the front focus, the image is in focus at the predetermined number. Therefore, in the defocus range of the divided regions, the region far from the optical center of each region has the rear pin side.

To give a concrete explanation based on FIG. 6 (1) which shows the difference data after taking it, FIG. 6 (b) shows the reference part and the reference part of the area (A), Consider the defocus range of area (A2). At this time, focus is achieved when the 15th - 15 = 34th image from the left end matches the image of the area (A2) in the reference section. From this, when the images match to the left of the reference part, it becomes front focus, and at this time, the maximum number of front focus deviation data (hereinafter referred to as deviation pitch) is 14, and when the images match to the right of the reference part, it becomes back focus, and this Then, the maximum rear pin deviation pitch is 14. The same is true for the divided defocus ranges in each of the other areas, and this is shown in Figure 8. Area (A1)
In this case, the front pin side deviation pitch is 4, the rear pin side deviation pitch is 24, and in area (A3), the front pin side deviation pitch is 24,
The rear pin side deviation pitch is 4. For regions (B) and (C), in region (B 1 ) and (CI >, the front pin side deviation pitch is 5, the rear pin side deviation pitch is 15, and the area (B
2>, (C2>, the front pin side deviation pitch is 15, and the rear pin side deviation pitch is 5.

FIG. 10 shows the circuit configuration used to perform focus detection and focus adjustment. (μC) is a microcomputer (hereinafter referred to as microcomputer) that performs calculations and controls necessary for focus detection and focus adjustment.

(DISPI) is the display part that displays the focus detection area in the photographing screen (S) of the viewfinder white coat display shown in Figure 5, and (DISPn) is the display part that displays the focus detection area in the viewfinder display shown in Figure 5. (S) A display unit that displays the outside focus state. (TEMPDET) is a temperature detection device that measures temperature with a temperature detection element (not shown, e.g. a thermistor) placed near the re-imaging lens pair inside the camera. (MOC) is used for focus adjustment. A motor control device that controls the motor; (M) is a motor for adjusting its focus; (ENC) is an encoder that detects the rotation of the motor (M); (LE) is a circuit in an interchangeable lens (not shown); , stores data necessary for focus adjustment.

(L E A), (L E B ), and (L E C) are the areas (A), (B), and (L E C) shown in FIG. C) are light emitting diodes that irradiate near-infrared light, respectively. (F 1
), (F 2 ), and (F 3 ) are filters provided to form a specific pattern on the subject;
l) is a random pattern of vertical stripes, (F2), (F3)
A random pattern of horizontal stripes is formed respectively. (
Trl) to (Tr3) are each light emitting diode (LEA)
This is a transistor for driving ~(LEC).

Next, a CCD control circuit used for focus detection will be explained. (CKTA), (CKTB), and (CKTC) are control circuits corresponding to each set of CCDs (reference section and reference section) shown in FIG. 6(a), and each circuit performs the same function. Since they have the same configuration, only (CKTA) will be described in detail in the circuit diagram, and detailed illustrations and explanations of other circuits will be omitted.

Note that signal lines with external circuits such as microcontrollers (μC) are described for all circuits (CKTA) to (CKTC).

First, in the control of the CCD, the integration time of the light receiving section and the accumulation section of the CCD will be explained. In the circuit (CKTA), (MA) is the light receiving part for the monitor mentioned above, (C1) is the capacitor for integration, and (SA) is the switch for controlling the integration, which handles one-shot integration from the microcontroller (μC). After being turned on and then turned off by the start signal,
Integration begins. (B1) is a buffer circuit that buffers the voltage of the capacitor (C1), and (COMPI) is a comparator that compares the integrated voltage with a reference voltage (Vref) and outputs an integration end signal. (ORI) inputs the integration end signal from the comparator (COMPI) or microcontroller (μC), and one-shot circuit (O3l)
This is an OR circuit that outputs a signal to One-shot circuit (
○Sl) is a one-shot signal (
IED), the data in the storage section is transferred to the CCD shift register, and the integration is completed. (B2) is a buffer for buffering the voltage of the capacitor (C1) obtained via the buffer (B1), and (M D E )
is a monitor data creation circuit that inputs the voltage signal from this buffer (B2) and creates digital data for AGC that determines the amplification factor of the shift register signal according to the voltage. The data is latched using the one-shot signal. In addition, each of the light receiving elements of the CCD is the above-mentioned monitor light receiving element (MA).
, a capacitor (C1), and a switch (SA), and integration is started by a signal from the terminal (○P11) of the microcomputer (μC).

Next, the operation until the data transferred to the CCD shift register is input to the microcomputer (μC) will be explained. C.C.
The data transferred to the D shift register is passed through an AND circuit (
Tarock φ1 sent via ANI) is held in the CCD shift register until it is input to the CCD shift register. When this clock is input, data is sequentially output in synchronization with this clock and sent to the microcontroller (μC). A gain control circuit (A G C: A
autoGa1n Control). This gain control circuit (AGC) is used to increase the analog signal (DTA) output from the shift register to a predetermined value or higher. The gain is X2. X4. Only X8 is used, and the gain is determined by the gain signal from the microcomputer (μC) (signal from the output terminal (Ot3)). Data whose gain is controlled by the gain control circuit (A c, c ) is converted into digital data by an A/D conversion circuit (A/D), and the microcomputer (μC) inputs this converted digital data. The AND circuit (AN
2) is the comparator (COMPI) of the circuit (CKTA).
> signals and circuits (CTKB), (CKTC)
Input the signal of the comparator (not shown, which works in the same way as COMPI) to the microcontroller (μC), and
An integration end signal indicating that the integration operation for D has ended is output.

Next, the switches (Sl) to (B5) will be explained.

(Sl) is a normally open switch that is turned ON when the release button (not shown) is pressed on the first stroke;
At N, focus detection, which will be described later, is started.

(B2) is a state changeover switch that switches between AF and FA, and when it is ON, it is AF, and when it is OFF, it is FA.

(B3) is a lens end detection switch that is turned ON when each end is reached when the lens is extended or retracted. (B4) detects whether it is in the vertical position or not, and whether it is in the vertical a position or the vertical position, and when the area (B) is on the lower side in the viewfinder display in Fig. 5, the switch is turned on to the a side. , when the area (C) is on the lower side, the switch is turned on to the 1] side.

The configuration of the switch (S4) for this purpose is shown in FIG.
P) is made of a conductor and is a kind of pendulum with a weight attached to the bottom (however, it is necessary to increase the friction so that it does not swing accidentally), and the other end is grounded to G N D. It is. The shaded areas (E a) and (E b) are electrodes, which are normally pulled up to the "11" level by the power supply ■ via a resistor. ), (E13>, when it comes into contact with
Pull town to "L" level.

Returning to Figure 10, the switch (S5) is for continuous AP mode, which adjusts the focus by following the movement of the subject even after focusing, and one-shot AF mode, which stops the focus adjustment once the target subject is in focus. This is a state changeover switch that switches between the two modes, and when turned on, the continuous AP mode is activated.

The operation of the focus detection and focus adjustment device constructed as described above will be explained with reference to the flowcharts of the microcomputer (μC) shown in FIG. 11 and subsequent figures.

When the switch (Sl) is turned on, a signal that changes from the rH level to the "L" level is input to the interrupt input terminal (INTI) of the microcomputer (μC), thereby causing the microcomputer (μC) to Execute the interrupt processing (■NTSI) shown in FIG. First, the microcomputer (μC) resets all flags and variables used, and inputs a conversion coefficient for converting the amount of defocus into the number of revolutions of the motor from the lens (steps #5 and #7). And the output terminals (OR3>, (OR3
) and (OR3) are set to "H" level, the transfer section is activated in order to eliminate the charge accumulated in the COD shift register, which is the storage section and transfer section of the CCD, before the operation of the microcomputer (μC). An empty transfer is performed (this is called CCD initialization) (step #10). In addition, clock φ1
Although not shown in the figure, after entering the flow of this interrupt, it continues to operate without stopping.

Next, the microcomputer (μC) determines whether or not it is in AF mode based on the signal level of the input terminal (IF5), and if it is in AF mode, it proceeds to step #25 and selects the
In order to display the focus detection area of P, a signal is output from the output terminal (Otl) to the display unit (DISPI), and step #3
Go to 0. On the other hand, if the FA mode is determined, the display section (DIS) displays the FA focus detection area shown in FIG.
PI) and proceeds to step #50.

The reason why the focus detection area is changed between the AP mode and the FA mode, and in particular, the focus detection area is limited to the center in the FA mode, is as follows.

Generally, when using the FA mode, the photographer focuses on a specific subject on the shooting screen while visually checking the viewfinder. In this case, if a focus detection area is set for a wide field of view in the FA mode, the focus detection value will shift due to objects other than the main subject (the subject to be photographed) included in the field of view. Such a phenomenon is more likely to occur as the focus detection area becomes wider. This is especially true when performing focus detection operations for a large number of areas as in this embodiment. For example, in this embodiment, although it is desired to focus on a relatively distant subject in area (A>), in area (B) or area (C)
If there is a subject relatively close to , focus detection information for this close subject will be displayed. Therefore, in order to prevent such a phenomenon, the focus detection area is limited to only the area (A>) in order to make the focus detection area relatively small. The display of the area should be made smaller to accommodate this.On the other hand, in AF mode, the focus detection area is wide, so you can solve the above problem, that is, if you want to focus on the subject in area (A), Although the problem of focusing on a relatively close subject in area B) or area (C) remains, on the other hand, focus detection can be performed over a wide range, so
Another advantage is that you can freely compose your shots.

Returning to the flowchart in Fig. 11, in the AF mode, after displaying the area, the microcomputer (μC) sends an auxiliary light flag (auxiliary light flag) indicating a request to emit the auxiliary light when it is dark and the focus cannot be detected. It is determined whether the auxiliary light flag (Auxiliary light F) is set (Step #30). If the auxiliary light flag (Auxiliary light F) is not set, the process proceeds to Step #50; If it is set, proceed to the flow from step #35 onwards in order to emit the auxiliary light.There are two types of auxiliary light emission in this embodiment.One is to emit three auxiliary lights with the lens stopped. As mentioned above, these three auxiliary lights are auxiliary lights for each area.The other is to drive the lens when all three auxiliary lights are emitted or the focus cannot be detected. While doing so, at a predetermined timing, only the auxiliary light corresponding to area (A) is illuminated to search for a subject whose focus can be detected.

The reason why the control for lighting the auxiliary lights is different in this way is that in a device that uses batteries as a power source, such as a camera, if three auxiliary lights are lit while driving the lens drive motor, one light emitting diode Number of hits 101oA ~ 1
This is because the current of 00IIIA is consumed, which puts a heavy burden on the battery, leading to a drop in voltage and possibly causing malfunction of the circuit. Focus detection, which particularly requires precision, does not malfunction due to voltage fluctuations or voltage drops, but it does tend to cause variations in detection data, which does not adversely affect detection accuracy. The same is true when there is a photometric circuit, and the luminance data of the photometric circuit tends to vary. In order to reduce these malfunctions and data variations, only the auxiliary light corresponding to area (A) is illuminated when driving the lens.

This also helps reduce current consumption.

In step #35 of FIG. 11, it is determined whether a flag (3BEF) indicating that three auxiliary lights are to be emitted is set, which is set when the lens drive is stopped and reset when the lens drive is started. is set, the output terminals (OP 8 ), (OP 9 ),
(OPI0) is set to rH, the three light emitting diodes (LEA), (LEB), and (LEC) emit auxiliary light (step #40), while the flag (38EP
) is not set, the output terminal (OPIO
) only to the rHJ level, and the light emitting diode (LEA) corresponding to the area (A>) emits light (step #45).
, after controlling both light emitting diodes to emit light, step #
Go to 50.

In step #50, the microcomputer (μC) outputs a one-shot signal from the output terminal (OPII) to start integration to the CCD. Next, reset and start the timer for measuring the integral time, and set the auxiliary light flag (auxiliary light F).
is set (step #55)
, 60). When the auxiliary light flag (auxiliary light F) is not set, that is, when the auxiliary light is not emitted, the process advances to step #95, and the input terminal (
The determination is made based on the signal level of IF6). If it is in AP mode, proceed to step #100, and determine whether a signal indicating that integration in the entire area has been completed is input from the AND circuit (AN2), and if not, 20 m5e
Determine whether c has elapsed (step #110), 2
If 0 m5ec has not elapsed, the process returns to step #95 and continues integration. If 20 m5ec has elapsed, the output terminal (OPI) outputs a positive level signal and proceeds to step #120 to end the integration in all regions (direct step #115). At step #100, when the integration over the entire region is completed, proceed to step #120,
Let's move on to focus detection calculations. If it is determined in step #95 that the mode is FA mode, the microcomputer (μC) determines whether the integration of area (A) has been completed based on the signal level of the input terminal (IPI) (step #105). If so, proceed to step #120. On the other hand, if the integration of region (A) has not been completed, the process proceeds to step #110;
The same control as above is performed.

When the auxiliary light is emitted, the auxiliary light flag (auxiliary light F) is set in step #60, so the process advances to step #65. Here, wait for 20m5ec to elapse, and when 20m5ec has elapsed, proceed to step #70 and check the input terminal (IF5) to see if the integration of the entire area has been completed.
Determine by. Here, even when the auxiliary light is emitted, 2Qmse
The reason for determining whether the integration of the entire area has been completed by c is as follows. In the embodiment, continuous AP is performed using the auxiliary light mode. Therefore, when following a moving subject and performing AP, the shooting scene may change and an initially dark area may become brighter, eliminating the need to use the auxiliary light. Not continuously emitting the auxiliary light in such a case is a waste of power, and the purpose is to eliminate this.

Therefore, when the completion of integration for the entire area is detected at step #70 by the input terminal (IF5), the flag (LLF) indicating darkness is reset (step #75), and the process proceeds to step #90. If it is determined in step #70 that the integration of the entire area has not been completed, step #80
Wait for m5ec to elapse, and after 3 Q +n5ec have elapsed, the integration end signal is sent to the output terminal (O
PI) and complete the integration (20m5ec~
In some cases, the integration of the entire area is completed within 80 m5ec), and in step #90, the terminal (○P 10), (O
R3>, (OR3) is set to "L" level to serve as an auxiliary light emission stop signal, and auxiliary light emission is stopped.

Next, the microcomputer (μC) stops the timer (step #120) and executes data input (data dump). This data dump subroutine is shown in FIG. 23 and will be explained. First, in order to make the output of analog data in area (A) more than a predetermined value, the AGCA data is transferred to the circuit (
G
C') (steps #3000, 3005>).

In order to input data from the transfer section of area (A), the microcomputer (μC) connects terminals (OR3) and (OR2) to r
r-i, rubel, and analog switches (ASI), respectively.
) is turned on, and the AND circuit (ANI) is set to a signal passing state (steps #3010 and #3015). Then, the microcomputer (μC) starts inputting data in area (A) (
Step #3020). When you have finished inputting the required number of data, stop data input and connect terminals (OR3) and (OR5).
is set to "L" level, the AND circuit (ANI) is set to a signal passage blocking state, and the analog switch (ASI) is set to OFF (steps #3025 to #3040).

Hereinafter, similar operations are performed in area (B) and area (C). Although the control signals and input/output data are different, the operations are similar, so the explanation will be omitted. Steps #3045 to #31
25). When the data input for areas (B) and (C) is completed, the process returns.

Returning to the flow shown in Figure 11, after completing the data input for all areas, the microcomputer calculates the difference data for every third area for each area (A), (B), and (C) for both the standard part and the reference part. , memorize this (steps #1, 30 to #140
). Note that the data for which the above differences have not been taken is also saved separately. A register (J
-30 is assigned to AR), (JBR), and (JCR) (steps #145 to #155). With this value,
(-) indicates the front focus side, and 30 is a value that cannot be taken by this detection device, and is used for later determination of the distance of the subject.

Next, a flag (LCF) indicating that focus cannot be detected is set (step #160). This flag (LCF) is reset when focus detection is possible during focus detection, which will be described later. Next, the microcomputer (μC) registers (DAR,) and (DBR) for storing the amount of differential in each area.
>, -KE is stored in (DCR) (steps #165 to #175). Here, -KE indicates a value that cannot be obtained by this detection device on the front focus side, and is used when detecting the subject closest to the camera (details will be described later).

Next, the microcomputer (μC) proceeds to the flow shown in FIG. 12 and performs focus detection calculations for area (A).

First, a focus detection calculation is performed for the area (A1) shown in FIG. 7 within the area (A). The microcomputer (μC) is in the area (A
1) Detect the peak value PAL from the raw data (data before taking the difference data) (step #180), and determine whether this peak value PAL is larger than the predetermined value KP (step #180).
Step #185). When the peak value PAL is larger than the predetermined value KP, it is determined that the data is reliable for performing focus detection, and the process proceeds to step #190, where the contrast CAI of the reference portion of the area (A1) is calculated as CA 1 = Σl ai-a -i+11i = 1 (step #190), in the above equation,
a indicates the difference data of the reference part. 1 is the order of the number of strokes from the left of the difference data. Then, it is determined whether this value CAI is larger than a predetermined value KC, that is, whether the contrast is sufficient for focus detection (step #195).

When the contrast value CAL is larger than the predetermined value KC, it is determined that the data is sufficient for focus detection, and the process proceeds to step #200.

In step #200, it is determined whether or not focus detection is disabled and the mode is for searching for a focus detectable area while driving the lens (hereinafter referred to as low-contrast search). When it is not in this low con- search mode, that is, when the low con- search flag (LC3F) is not set, correlation calculation is performed in step #205 based on the following equation.

a indicates the difference data of the reference part, and a' indicates the difference data of the reference part. i is the order of the number of strokes from the left of the differential data. j
is the number by which the reference part is shifted.

If it is determined in step #200 that a low contrast search is in progress, the process proceeds to step #210, where the lens moving direction is determined, and if the flag (MMBF) is not set and does not indicate the retracting direction, that is, in the lens extending direction. If yes, proceed to step #205, perform the above correlation calculation,
When the flag (MMBF) is set, that is, when the lens renormalization direction is set, the process proceeds to step #215, and a correlation calculation is performed. The correlation calculation in step #215 differs from step #205 in the number of relative shifts.

The reason for this will be explained below based on FIG.

As shown in FIG. 8, each divided area (Al).

For (A2> and (A3)), the defocus range (shift pitch amount) is different based on the in-focus point. For example, in area (A1), the front focus side is 4 pitches and the rear focus side is 24 pitches. In such a case, considering the above-mentioned low-contrast search, first of all, when the lens is extended, the lens is extended to search for the subject on the back focus side (close distance side), so the subject is not in the back focus. If it exists on the front pin side, it can be detected. Therefore, it is necessary to shift it over the entire area of the reference part. Although not necessarily necessary, the subject may be detected due to changes in the subject or changes in external light, so approximately 4 pitches are left as the range for correlation calculation.

On the other hand, in the case of a low-contrast search in which the lens is retracted, the lens is retracted to search for a subject on the front focus side (far side), so it is sufficient to perform a correlation calculation with the reference part of the part that has the front focus. Therefore, in this case, it is j-5 when in focus, so the shift amount can be 1 to 4, but for the same reason as above, 4 pitches from 6 to 9 are added to give a margin, resulting in a total shift of 9 pitches. I do. As a result, the calculation time during the time-consuming low-contrast search can be shortened as much as possible, the interval between focus detection calculations can be shortened, and the detection capability can be improved.

Returning to Figure 12, after completing the correlation calculation, the microcomputer (μC
) obtains the minimum correlation value (maximum correlation degree) among those obtained by shifting (step #220), and performs an interpolation operation to find the true minimum value from this arithmetic correlation value (step #220). #225).

This subroutine is shown in FIG. 24 and will be explained as follows. ), MA 1 (j+ 1 ) (this is MA(j+
1) is used to find X as the correction amount from the shift amount j, and this is added to the above-determined j to find the true shift amount (steps #3200 to 3210).

However, regarding interpolation calculations, this is not the gist of this application, so
Explanation will be omitted. ) Find the minimum correlation value MA(j) at this time from the true shift amount j found by interpolation calculation, set this as YM, and return (step #3215, 3
220).

Returning to FIG. 12, the obtained YM is normalized by the contrast CA1, and it is determined whether this value is smaller than a predetermined value KY (step 8230). If the data is smaller than the predetermined value KY, it is reliable data and the focus can be detected.
Step #2 to reset the low contrast flag (LCF)
35), subtract 5 (shift number at the time of focusing) from the obtained j to obtain the amount of back focus after focusing (step #240>, and determine whether this j is larger than 17 (step #24)
5>.

The reason for this determination is that in this embodiment, the focus is set on the closest distance among the detected areas (areas (A), (B), (C) and each divided area) as described above. As can be seen from Figure 8, the divided area (A1)
If the rear pin side exceeds 15, the rear pin is the largest compared to other areas, and it is useless to perform calculations in other areas, so j is determined in order to avoid this waste. Now, the judgment for j is j>17, but as you can see from the above, in reality, j>15 is sufficient, and j>1
The reason why it is set to 7 is because it is a value that includes variations, so it may be 16 or a little over 15.

In step #245, when j is larger than 17, the area (
The defocus amount Δε is determined by multiplying j by the defocus amount SA per pitch in A) (step #260).

The amount of defocus per pitch is determined by the optical system and position m
It is a constant that changes from region to region. Therefore, this data may be prepared for each camera and stored in, for example, an E2PROM (electrically programmable and erasable ROM).

Next, the detected temperature is input from the temperature detection circuit of the microcomputer (μC) (step #270), and the reference defocus correction amount Δε(1) for changes in the focus detection optical system due to temperature is determined from the memory table (not shown). , and since the change in defocus amount differs for each region, the coefficient 1 (A) corresponding to the region (A) is read out from the memory table and multiplied by the reference defocus amount to calculate the corrected defocus amount Δε′ for the temperature t. (Step #275).Next, the correction amount △εA is calculated to correct the error in the optical axis direction during assembly for each region.
(Z), the above-mentioned temperature correction amount Δε", and defocus amount Δε to find the correct defocus amount, and store this in the register (DAR>) (step #280
, 282). Then, it is determined whether it is in AF mode, and the AP
If it is the mode, the process proceeds to the flow of "AP calculation" to perform lens drive control, and if it is the FA mode, the process proceeds to the flow of "display control" to display focus detection (step #285>).

In step #185, the peak value PAL is set to a predetermined value K.
When contrast CAL is below P, or when contrast CAL is below a predetermined value KC in step #195, or when standard value YM/CAL is above a predetermined value KY in step #230, the respective obtained data is in focus. A focus detection calculation is performed on a region (A2) obtained by dividing the region (A) as an unreliable object for detection. Step #245
When j is 17 or less, store this in a register (JAR)
Then, the process proceeds to focus detection calculation for area (A2).

The focus detection calculation in this area (A2) is almost the same as the focus detection calculation in the area (A1), as shown in FIG. 13, so the different parts will be mainly explained. In steps #290 to #35o, various data, that is, peak value data PA2. Contrast data CA2. The standard value YM/CA2 is different and steps #320 to 33
0 is different.

It goes without saying that the various data are different, so the explanation will be omitted, and steps #320 to #330 will be explained. Step #32
At 0, a flag indicating lens renormalization (MMBF)
is set, set the shift amount j from 1 to 19. When it is not set, it is set as j-11 to 29, and k of the reference part pixel (ai+k) is set to 10 so that the data in the reference part is 20 in the 11th to 30th (A2) area from the left (however, k is set to 10). i=1-20). When extending the lens (MM
The shift number is different between when the lens is extended (BF=0) and when the lens is retracted (MMBF=1), as explained in steps #205 to #215, and when the lens is extended, j=
Shift number j-11 to 29 at 4 pitches on the front focus side when the rear focus is opened after 15, and j-15 at the time of focus during renormalization.
With 4 pitches on the rear pin side and the opening of the front pin, the number of shifts is j=1 to 1.

In step #355, 15 (the number of shifts during focusing) is subtracted to obtain the amount of focus after focusing, and this value is determined by the register (J) that stores the number of shifts in the area (A1).
AR) (step #360), and if it is larger than this memorized value, a new area (A2) is created.
The shift number is stored in the register (JAR) (step #365), and if it is small, this step #365)
, and both proceed to step #370. When the value of the memorized register (JAR) is greater than 6, the routine proceeds to calculation A, and when it is 6 or less, the process proceeds to the focus detection calculation for the next area (83). The reason for this is that since the maximum defocus pitch of the rear focus in area (A3) is 4, if this value is exceeded, it is useless to perform focus detection in area (A3).

Now, the reason why this boundary value is 6 is step #245
This is because, similarly to the above, there is a margin including focus detection error. Step #295. Step #305, Step #3
45, if the focus detection data is unreliable, the area (
Proceed to A3) focus detection.

Next, the focus detection calculation for area (A3) will be explained with reference to the flowchart of FIG. 14. Again, steps #380 to #435 contain different data, but steps #180 to #180 of the focus detection calculation flow for area (A1)
Since the processing is similar to that of 235, only the different parts will be explained and the other explanations will be omitted. In step #410, when the flag indicating lens retraction (MMBF> is not set, that is, when the lens is extended, it is sufficient to perform focus detection in the rear focus direction, and the shift number at the time of focusing is set to j-25. , the number of shifts should be j-21 to 2 for the rear pin opening and 4 pitches on the front pin side (step #
41.5). On the other hand, when the flag (MMBF) is set, that is, when the lens is retracted, it is necessary to perform focus detection in the front focus direction, so all the numbers j-1 to 2 are shifted (step #405). Step #43
5 to step #440, 25 (number of shifts during focusing) is subtracted from j in order to detect the amount of focus after focusing, and this value is greater than the number of shifts stored in the register (JAR). If it is large, this value is stored in the register (JAR) and the register (JAR) is
If it is less than the number of shifts stored in memory, step #450
, and both proceed to the routine of operation A (steps #440 to #450).

Step #385. Step #395. Step #43
If the data obtained in step 0 is not reliable for focus detection, the process proceeds to step #455, where it is determined whether a flag (LC3F) indicating a mode in which a focus detectable area is searched while driving the lens is set, and the flag (LC3F) is set. If so, the process proceeds to step #460, and it is determined whether a flag (LLF) indicating low brightness is set. If it is set, the process proceeds to the flow of undetectable determination.

As mentioned above, while driving the lens (LC3F=1
) Mode that lights up the auxiliary light to search for the focus detection area (L
LF=1), area (A) (area (A1), (A
2) and (A3)), so the correlation calculation for area (B) does not proceed. Flag (LC3F)
, (LLF), if one of the flags is not set, the process advances to step #465, and it is determined whether the mode is AP mode by detecting the level of the input terminal (IP6).
If it is determined that the mode is AF mode, the process proceeds to the correlation calculation flow for area (B), and if it is the FA mode, the process proceeds to the flow for display control of the focus state without performing the correlation calculation for area (B).

Next, the routine of operation A in FIG. 15 will be explained.

Multiply the shift number j stored in the register (JAR) by the defocus amount SA per pitch in the area (A) to find the defocus amount Δε (step #468.
470). Input the temperature from the temperature detection device (TEMPDET), read out the standard defocus correction amount Δε (shi) of the focus detection optical system for the temperature from the table, and calculate the area (A
), read out the coefficient I (A) from the table and multiply it by the standard defocus correction amount Δε(1) to find the corrected defocus amount Δε° with respect to temperature (step #475.480).Optical axis Directional assembly error ΔεA
(Z) and the above correction amount Δε゛ to the defocus amount Δε to find the correct defocus amount (step #485)
, store this in the register (DAR) (step #4
87). Next, the microcomputer (μC) determines whether or not it is in the AF mode by detecting the level of the input terminal (IP6) (step #490). If it is determined to be in the AP mode, it calculates the correlation in area (B).゛B correlation ° showing the flow of
If it is determined that the mode is FA mode, the process advances to the flow of ``display control'' which displays the focus detection state.

First, to explain the flow of "display control", the microcontroller
In C), it is determined whether or not a flag (LCF) indicating that focus cannot be detected is set, and when the flag (LCF) is set, the undetectable display explained in FIG. 5 is displayed on the display unit (DISPn). display (step #525),
Proceed to the flow of "'FA'".

If the flag (LCF) indicating that focus cannot be detected is not set, the process proceeds to step #500, and it is determined whether the absolute value 1Δε of the defocus amount is less than or equal to a predetermined value ε indicating the focusing range. , if the predetermined value is less than or equal to ε, the display unit (DISPII>) displays the focus (step #52
0), when the predetermined value exceeds ε, the display unit (DISP II) displays the front focus if the defocus amount is negative, and the rear focus if the defocus amount is negative. Proceed to “'FA” flow (steps #505 to #51
5).

Next, the flow of "B correlation" will be explained. This flow is a flow for performing correlation calculation for region (B). Microcomputer (μ
C) is step #53o, in which it is determined whether or not the vertical a position is detected by detecting the levels of the input terminals (I B4) and (I P3). In the display, when the focus detection area (B) side is arranged at the bottom, it is assumed that there is almost no subject to be photographed in the lower position like area (B), and this area (B) is
) focus detection is not performed. The reason for this is that even if you ignore area (B), you can usually capture the subject in area (A), and if the subject you want to photograph is in area (A>), you can capture it in area (A>). In many cases, there is another subject closer to the lens than the subject you want to photograph (for example, a person in area (A) and an object in area (B) in front of the person's feet). This is to prevent this from happening. Therefore, when the Nga position is determined in step #53o, Proceed to PAC correlation "'" which is the flow of correlation calculation.

If it is not in the vertical a position, proceed to step #545, but
In steps #545 to #600, a correlation calculation is performed for area (B1), and the processing in the steps between these steps is the same as steps #180 to #235 for area (A1), so only the different parts are will be explained, and other explanations will be omitted. In step #575, if the flag indicating lens renormalization <MMBF) is not set, a correlation calculation is performed with the entire area of the reference part (step #570
).

This is because the region (B1) has the rear pin side as described above. On the other hand, when the flag (MMBF) is set, the front focus is opened centering on the shift amount j-6 at the time of focusing, and the rear focus is set to 4 (with a margin), and j = 1.
Perform correlation calculation with the reference part in the range of ~10 (step #5
80).

In step #550, when the peak value FBI is less than or equal to the predetermined value KP, and in step #560 when the contrast CB1 is less than or equal to the predetermined value KC, in step #595, the standard value YM
When /CB1 is greater than or equal to the predetermined value KY, the process proceeds to the correlation calculation in area (B2). In step #605, the shift amount j
Subtract 6 from , calculate the back pin amount, and store this in the register (J
BR), and it is determined whether this is greater than 7 (steps #610, 615). When the shift amount j is larger than 7, it is useless to perform the correlation calculation in the area (B2), so "operation B'" is performed to calculate the defocus amount.
’ routine. j>7 in step #615 should originally be j>6, but it is set to j>7 to include an error. This is similar to the determination in step #245 in area (A). Then, in step #615, if j is 7 or less, the process proceeds to the correlation calculation for the area (B2).

FIG. 16 shows the correlation calculation for region (B2). Step #
Since steps 620 to #680 are the same as the correlation calculations from steps #545 to #600 in the (B1) area,
Only the different parts will be explained. When the flag (MMBF) indicating lens renormalization is set in step #655, a correlation calculation is performed with all reference parts (step #655).
650), and when the flag (MMBF) is not set, the area (j
= up to 21) and j-1 including the area of 4 pitches on the front pin side
Correlation calculation is performed with the reference part in the range of 2 to 21 (step #
660). When the peak value PB2 is less than or equal to the predetermined value KP in step #625, the contrast C is determined in step #635.
When B2 is less than the predetermined value KC, in step #675, if the standard value YM/CB2 is less than the predetermined value KY, it is determined that the reliability of focus detection is low and the process proceeds to correlation calculation for area (C).

In step #685, j = 16 at the time of focus is subtracted from j, and compared with the value j stored in the register (JBR). If it is larger than the value stored in the register (JBR), the subtraction is performed. The obtained value j is stored in the register (JBR
), step #695), while if it is smaller than the memorized value, step #695)
is skipped and the routine proceeds to "operation B" (steps #690 and #695).

In the routine of operation B', the value stored in the register (JBR) is set to j, the defocus amount SB per 1-pitch of the area (B) is read from the memory table, multiplied by j, and the defocus amount ( Δε) (steps #700 and #715). Temperature detection device (TEMPD)
The measured temperature is input from the input terminal (Itl) from ET), and the reference defocus correction amount Δε(1
) is read out from the table, and the above reference defocus correction amount △ε(1) is multiplied by the temperature coefficient KB in area (B) to obtain the corrected defocus amount △ε゛ (Step #7
20. #725). Next, read out the defocus amount Δε, the correction amount Δε′ obtained above, and the correction amount ΔεB(z) for correcting the error in the optical axis direction during assembly from the memory table, add them all, and create a new Defocus amount Δ
Calculate ε, store this correction amount in the register (DBR), and proceed to correlation calculation for region (C) (step #730.
#735).

In the correlation calculation for area (C), first the camera position is vertical 1]
It is determined whether or not it is the current position (step #740). If the camera is in the vertical position, the area (C) will be below the subject, so the area (C) will be removed to exclude it from the focus detection target.
The process proceeds to a routine for determining undetectability without performing the correlation calculation. If it is not in the vertical position, the (C1) area and (C2
) performs a correlation calculation for the area.

This is shown in steps #745 to #920, but as can be seen from FIG. 7, area (C) is symmetrical with area (B) about the center of the screen, and is vertically identical, so the algorithm for detecting the focus is almost the same as steps #545 to #735 (with the exception of variables, calculation results, registers, and other values that differ from region to region). Therefore step #
Explanation of steps 745 to #920 will be omitted. The different parts are areas (B
), the focus detection data is unreliable, or
After focus detection is completed, the process advances to area (C), and in area (C), a routine called ``'Detection undetectable determination'' is performed to determine whether or not focus detection is impossible in the above two cases. This is the point where we move on.

FIG. 19 does not show the routine for "determining undetectability." In step #925, the microcomputer (μC) determines whether or not focus detection was possible using the flag (L) indicating that focus detection is not possible.
CF). This flag (LCF) is set at the start of focus detection and is reset when focus detection is possible in each area.
When the LCF) has been reset, the process proceeds to the ``area determination routine'' which determines the area of the rearmost pin. On the other hand, when the flag (LCF) is set, the area (A
) to (C>), the focus is determined to be undetectable (low reliability) and the process proceeds to step #930.

In step #930, it is determined based on the auxiliary light flag (auxiliary light F) whether or not the auxiliary light has been emitted in the current focus detection. First, a case where this auxiliary light flag (auxiliary light F) is not set, that is, a case where focus detection is performed using only steady light will be explained.

In steps #935 to 945, it is determined whether the AGC data in each area (A) to (C) exceeds 4, and if none exceeds 4, focus detection using constant light can be performed. The flag (LLF) indicating low brightness and the auxiliary light flag (auxiliary light F) are reset (step #950, 9
60). (In addition, the setting of this flag becomes meaningful when proceeding from step #1000 described later.) Then, in the flow of "low-contrast scan" that searches for a focus detectable area while driving the lens. Proceed. Step #93
5 to Step #945, if the AGC data in any one of the areas (A) to (C) exceeds 4, the process proceeds to Step #965. Step #96
In step 5, it is determined whether or not the previous focus detection result was in focus, and if it is not in focus (the focus flag is not set), variable N1 is reset to O to indicate low brightness. Set the flag (LLF) (step #
980.985). The variable N1 above is for when the auxiliary light is emitted in continuous mode and the focus is reached, the auxiliary light is not emitted before and after each focus detection, but once every multiple focus detections. (Details will be described later).

Next, it is determined whether a flag (LSIF) indicating prohibition of low contrast scan, which searches for a focus detectable area while driving the lens, is set (step #990).

This prohibition of low contrast scan is set when a focus detectable area cannot be obtained after performing a specified operation, and when this flag is set, the emission of the auxiliary light is prohibited. . The reason for this is that once it has been determined that no-point detection is impossible (after low-contrast scanning with the auxiliary light), it is useless to perform focus detection with the auxiliary light on, and only increases current consumption. This is because only

For this reason, a flag (L
SIF) is set, step #995
In order to perform focus detection without emitting the auxiliary light without proceeding to the auxiliary light emission mode from ``A'' (the auxiliary light F is set to 0).
Proceed to the routine P". In step #990, if the flag (LSIF) is not set, the auxiliary light flag (auxiliary light F) is set, the motor is stopped, and 3
In order to perform focus detection using the beam, set the 3-beam flag (38EF) and proceed to the "AF" flow (
Step #995. #996. #997).

In step #965, if the previous focus was in focus, 1 is added to the variable N1, and it is determined whether the value becomes 5 (steps #970 and #975).

If the variable N1 is 5, proceed to step #98o and set the variable N1 to 5.
1, proceed to the above flow, and set variable N1 to 5.
Otherwise, proceed to the "AF" routine.

As a result, light emission after focusing is performed once every six focus detections, reducing current consumption.

When the auxiliary light flag (auxiliary light F) is set in step #930, the process proceeds to step #1000, where it is determined whether or not the low brightness flag (LLF) is set. , step #950
Proceed to , and remove from auxiliary light mode. On the other hand, the flag (L
LF> is set, reset the flag (3BEF) indicating the 3-beam auxiliary light (step #
1oo5), proceed to the low contrast scan flow.

Next, a flowchart of the low contrast scan will be described with reference to FIG. 20. First, the microcomputer (μC) sets a flag (LC3F) indicating low contrast scan, and sets the counter N for controlling the drive amount of the motor to the maximum value (- amount of drive for focus detection (number of pulses from encoder)). ). This prevents the lens from stopping in focus detection during low contrast scanning, even if focus cannot be detected (steps #1010, #1015).

Next, it is determined whether the lens exists at the end of the drive range by checking whether the switch (S3) is ON or not, and if it is OFF, that is, when it does not exist at the end, a flag indicating low contrast scan prohibition is set. It is determined whether (LSIF) is set (steps #1020 and 1025).

When the flag (LSIF) is set, the low contrast scan is not performed and the process proceeds to the "AF" flow. When the flag (LSIF) is not set, it is determined whether or not the flag (MMBF) indicating lens retraction is set, and if it is set, the lens is retracted, and if it is not set, it is a signal indicating control of lens extension. , and set the motor rotation speed to high speed (H
igh 5peed, “old speed” in the diagram
Motor control circuit (MOC,)
The motor control circuit (MOC) controls the motor according to the input control signal (steps #1030 to
1045). Next, a flag (MDF) indicating that the motor is being driven
is set, a control signal is output to the display section (DISP II) to turn off the display indicating the focus detection state, and the process proceeds to the AF''' routine (steps #1047 and #1050).

In step #1020, when the termination is detected, the microcomputer (μC) sends a motor stop signal to the motor control circuit (M
OC) and flag (MD) to indicate motor stop.
F) reset (step #1055, #], 05
7). Next, a flag (LSI
Step #1: Determine whether F) is set.
060), if set, the process proceeds to the "'AF" routine without performing a low contrast scan; if not set, the process proceeds to step #1065. Step #1
In 065, a flag indicating lens renormalization (MMBF)
Determine whether or not is set. When the flag (MMBF) is not set, it indicates that the lens drive has been extended to the end, so in order to continue to control the retraction, the flag (MMBF) is set.
BF> is set, the process proceeds to step #1040, and the motor is controlled. In step #1065, if the flag (MMBF) is set, it is assumed that the focus detectable area cannot be detected even if the lens is retracted and extended, and the auxiliary light is emitted at the next focus detection. Fill-in light flag (fill-in light F) to prohibit
and resets the flag indicating prohibition of low contrast scan (
LSIF), prohibits the next low contrast scan, and displays focus detection failure on the display (DI 5PIE).
(Steps #1075 to #1085).

Next, the microcomputer (μC) determines whether or not it is continuous mode based on the state of the switch (S5), and if it is continuous mode, it selects "AF" to perform focus detection next. If the mode is not continuous mode, the process proceeds to the routine 59- and waits for the next interrupt, specifically, for the switch (Sl) to be turned on again.

Next, we will explain which area's defocus amount to select from among the defocus amounts of each area obtained when focus detection is possible, using the ``area determination'' routine shown in Figure 21. As mentioned above, this focus detection device focuses on the subject closest to the camera. All you have to do is choose.

In the routine of “'area determination °’, step #1095
゜#1100. In #1115, the maximum defocus amount is detected, the defocus amount of the area where the maximum defocus amount is detected is set as the defocus amount (DF), and the process proceeds to the AF calculation part calculation part to calculate the lens drive amount. (
Steps #1095 to #1120).

Since focus detection is possible in the "AP calculation" routine, a flag (MMBF) indicating lens renormalization is used.

A flag (LSIF>) indicating prohibition of low contrast scan.

Reset the flag (LC9F) indicating low contrast scan and set the flag (3B6O-EF) for emitting 3-beam auxiliary light (steps #1125 to #1140
). Next, the defocus amount (DF) obtained above is multiplied by a coefficient ≧L for converting to the motor rotation speed to obtain the motor rotation speed N (step #1145).

Next, it is determined whether or not the motor is being driven using a flag (MDF) indicating that the motor is being driven.Step #11
50), when this flag (MDF) is not set (when the lens is stopped), the absolute value INI of the motor rotation speed determined above is set to a predetermined value I(
If it is within a predetermined value, it is determined that the focus is in focus, and the focus flag (focus F
), set the focus display on the display (DISPII), and set the auxiliary light flag (auxiliary light F) to prohibit the auxiliary light emission.
) (Step #1160 to Step #1
170). Then, it is determined whether or not it is continuous mode, and if it is continuous mode, “'A
Returning to the routine of "P", focus detection is repeated, and if the mode is not continuous mode, the process waits for an interrupt (step #1175).

Step #l], 50, when the motor is running (when the flag (MDF) is set), or when step #11.55 is not in the ready state (
When the absolute value INI of the rotational speed exceeds a predetermined value +N), the process proceeds to step #1180, and a flag <focus F> indicating focus is reset.

Next, a predetermined value I (d) indicating whether the absolute value IN+ of the rotation speed is within a range near focus is determined, and a predetermined value Kt
If it is below +z, the motor rotation speed is set to low speed (
I, our 5peed, "Lospe" in the picture
The motor control circuit (abbreviated as ``e d'') is used to generate a signal that causes high speed if it exceeds a predetermined value +iZ.
A flag (MD) indicating that the motor is being driven is output to
F) (steps #1185 to 1200).

Then, it is determined whether the current focus detection was performed using an auxiliary light by checking whether or not the auxiliary light flag (auxiliary light F) is set, and if it is set, it waits for an interrupt and sets it. If not, the process proceeds to the AF" flow to perform focus detection. This allows focus detection, and when the auxiliary light is emitted, focus detection is not performed while the lens is being driven.

Next, the flow of 'INTENC', which interrupts every time a pulse from the encoder circuit (E N C) comes, is changed to the second flow.
2, motor control and focus detection control during motor drive will be explained. First, the microcomputer (μC) subtracts 1 from the number of revolutions (N) every time it enters this flow (step #
1210). Next, it is determined by the flag (LC8F) whether or not low contrast scanning is in progress, and if low contrast scanning is in progress (LC8F=1), the process proceeds to step #1270;
A switch (S3) determines whether the lens is at the end.

If it is not the end, it returns, and if it is the end, it outputs a signal to stop the motor, and a flag (M
DF) and return (Step #127
5.1280>. In step #1215, if the flag (LC3F) indicating low contrast scan is not set, the process proceeds to step #1220 and checks whether the absolute value INI of the rotation speed is within a predetermined value I (NZ) indicating the vicinity of focus. If the predetermined value I (NZ) is exceeded, a signal for controlling the motor at high speed is output to the motor control circuit (MOC) in step #1260, and the process proceeds to step #1265.On the other hand, If it is within the predetermined value, a signal for controlling the motor at low speed is output to the motor control circuit (MOC) in step #1225,
Determine whether the variable N h < o (step #1230>. If the variable N is not 0, proceed to step #1265, and check whether the focus detection was for the auxiliary light emission or not using the auxiliary light flag (auxiliary light flag). If the auxiliary light flag is set, it is assumed that the auxiliary light has been emitted and an interrupt is awaited; if the auxiliary light flag is not set, the process returns to the step where the interrupt occurred.

In step #1230, when the variable N becomes 0, a control signal to stop the motor is sent to the motor control circuit (MOC).
and reset the flag (MDF) (steps #1235 and 1240). Next, the focus detection for the auxiliary light emission is determined by the auxiliary light flag (auxiliary light F) (step #1245), and if it is set, the focus detection for the auxiliary light emission is determined in step #1245). 1250
Step #1255), it is determined whether or not the flag indicating low brightness (LLF) is set, and if it is not set, the auxiliary light flag (auxiliary light F) is reset. When LLF) is set, step #1255 is skipped and the flow proceeds to "AF" to perform focus detection in both cases. On the other hand, if the auxiliary light flag (auxiliary light F) is not set in step #1245, the process returns to the step where the interruption occurred.

A modified example is shown below. In the above embodiment, in the case of the vertical position, the correlation calculation was not performed for the area (B) if the vertical position is a, and the correlation calculation of the area (C) if the vertical position is not performed, but as an alternative, even if the vertical position is Phase-to-phase calculation is performed, and at position 111a, the defocus amount of area (B) is the maximum, and between the defocus amount of area (B) and area (A) or (C), the defocus amount is larger on the rear focus side. When the absolute value of the difference with the amount is less than a predetermined value, the defocus amount △ε8 of this area (B) and the larger defocus amount on the rear focus side of the area (A) or (C) Using both (ΔεA, Δε.), the defocus amount Δε is expressed as Δ ε −K ・ Δ εB+ (1−K) ・ M
Similarly, at the AX (Δ εA, Δ ε.) (0<K<1>. Vertical 1) position, the area (C
) has the maximum defocus amount, and the absolute value of the difference between the defocus amount of area (C) and the defocus amount that is larger on the rear focus side of area (A> or (B)) is less than or equal to a predetermined value. When, Δ ε −K ・8 εC+(1−K)・MAX(
Δ ε to Δ εB).

This is because there is a possibility that a subject exists in both cases, and in this case it is dangerous to adopt only a single area and use the defocus amount, so the above area (B), One of (C) and the other larger defocus amount are used as the defocus amount. To do this, follow step #530 of FIG. Step #740 in FIG. 17 may be deleted and the routine for "region determination" in FIG. 21 may be changed to the one shown in FIG. 25. Here, K in the above equation is set to (1/2).

In the flow of FIG. 25, when area (A) has the maximum amount of defocus, that is, DAR(≠−K E )≧
When DBR≧DCR, step #3300, step #3305. Proceed to step #3310, area (A
) is used. DBR≦DAR<D
If CR, step #3300. #3305. #
Proceed to 3315. In step #3315, if it is determined that the Hb position is not located, the defocus amount of area (C) is used (step #3325); if it is at the [l) position, the defocus amount of area (A) is used. D.A.R.
--KE When it is E, that is, when the focus cannot be detected, the defocus amount of area (C) is still used.

When D A R = -K E, it is determined whether the absolute value of the difference between area (C) and area (A) is less than a predetermined value K D F, and when it is less than a predetermined value K D F, the defocus amount DF is determined. As, DF-(1/2)(DAR+DCR)
(Steps #3320 to #3323).

When the predetermined value K DF is exceeded, the defocus amount of area (A) is used as the defocus amount.

When D CR > D B R > D A R, the process proceeds to steps #3300, #3330, and #3335, and when it is determined in step #3335 that it is not in the vertical position, the defocus amount of area (C) is used. . When it is in the vertical position, it is determined whether the absolute value of the difference in defocus amount between area (B) and area (C) is less than or equal to a predetermined value KDF, and when it is less than or equal to the predetermined value, the defocus amount is determined as
Use DF=1/2 (DBR+DCR) (steps #3340. #3342). When the predetermined value KDF is exceeded, the defocus amount of area (B) is used as the defocus amount.

When DBR is at the maximum defocus amount, step #33
00. #3330. Proceed to #3345 and step #33
When it is determined in step 45 that the vertical position is not a position, the defocus amount of area (B) is used.

When DBR is at the maximum defocus amount and at the ma position, DB
R, ≧D CR> D A R, and l DCR
- If DBRl is less than the predetermined value K D F, the defocus amount (DF) is DF = (1/2) (DBR + DCR)
is used. When DBR>DAR≧DCR, it is determined in step 13355 whether the defocus amount of the area (A> is DAR=-KE, and when DAR=-KE, , area (A)
.

(C) Assuming that focus cannot be detected in both areas, the defocus amount of area (B) is used, and if DAR≠-KE, area (
It is determined whether the absolute value of the difference in defocus amount between A) and area (B) is less than or equal to a predetermined value KDF, and if it is less than or equal to the predetermined value KDF, DF-(1/2)(DAR+DBR) is determined. If the predetermined value K D F is exceeded, DF=DBR is used (steps #3360 and #3362). still,
K is not limited to (1/2).

Furthermore, although correction in the optical axis direction is performed for each focus detection area in the embodiment, it goes without saying that the accuracy of focus detection can be further improved if correction is performed for each block divided into each area.

When correcting the amount of defocus due to temperature changes, instead of finding the standard defocus amount for temperature changes and multiplying this standard amount of defocus by a different coefficient for each area to find the corrected defocus amount. , a memory table storing the corrected defocus amount may be prepared, and the obtained defocus amount may be corrected using this memory table to obtain the true defocus amount.

(Effects of the Invention) As described above, the present invention temperature-compensates the defocus amount obtained from the image spacing on the image sensor array according to the lens spacing of the re-imaging lens pair corresponding to each image sensor array. Because
Even if there is a difference in the amount of thermal expansion between the lenses of the pair of re-imaging lenses due to a difference in the distance between the lenses, there is an effect that accurate focus detection can be performed.

As mentioned in the explanation of the embodiment, the configuration can be simplified by assuming that the temperatures of each pair of re-imaging lenses are approximately the same and detecting the temperature at only one location. It is.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for explaining the present invention in detail, FIG. 2 is a perspective view showing a schematic configuration of an automatic focus detection device according to an embodiment of the present invention, and FIG. 3 (a) (1)) and Figure 4 (
a) to (c) are explanatory diagrams of the same operation as above, Fig. 5 is a front view showing the display in the finder as above, Fig. 6 (a) (1))
7 is an explanatory diagram showing details of the CCD chip used in the above.
The figure is an explanatory diagram showing the divided areas of the reference part in the CCD chip same as the above, FIG. 8 is an explanatory diagram showing the shift amount for the divided areas same as the above, FIG. Figure 10 is a circuit diagram of the control circuit used in the above.
FIGS. 11 to 25 are flowcharts for explaining the operation of the same. (1) is the first calculation means, (2) is the temperature detection means, (3
) is a temperature compensation means, (4) is a second calculation means, a is an imaging lens, d, , d2. d3 is a reimaging lens pair, el
, e2, and e3 are image sensor arrays.

Claims (4)

[Claims] (1) The image formed by the photographing lens is re-formed as first and second images on the array of image sensors arranged in a row by a pair of re-imaging lenses, and the image interval between the first and second images is adjusted. A plurality of focus detection units are provided for detecting the focus adjustment state of the photographing lens by detecting from the output of the image sensor array, and the lens interval of at least one pair of re-imaging lenses is different from the lens interval of the other pair of re-imaging lenses. A first calculating means for calculating a defocus amount according to an image interval between a first image and a second image on the image sensor array detected from the output of each image sensor array; Temperature detection means for detecting the temperature near the imaging lens pair, and a temperature compensation amount for the defocus amount for each focus detection area according to the temperature detected by the temperature detection means and the lens interval of each re-imaging lens pair. temperature compensation means for calculating the temperature compensation amount, and a second calculation means for calculating the temperature compensated defocus amount from the defocus amount obtained by the first calculation means and the temperature compensation amount obtained by the temperature compensation means. An automatic focus detection device comprising: (2) The automatic focus detection device according to claim 1, wherein the temperature detection means is a detection means that detects temperature at only one location. (3) The temperature compensation means includes a storage means that stores a temperature compensation amount corresponding to the lens spacing of each re-imaging lens pair that changes depending on the temperature, and a temperature detection means that stores the temperature detected by the temperature detection means and 2. The automatic focus detection apparatus according to claim 1, further comprising a selection means for selecting an amount of temperature compensation from a storage means in accordance with the area to be detected. (4) The temperature compensation means includes a storage means that stores a basic defocus amount that changes depending on temperature and a compensation coefficient corresponding to the lens interval of each re-imaging lens pair, and a temperature detected by the temperature detection means. Claims characterized by comprising: calculation means for calculating the temperature compensation amount from the basic defocus amount and compensation coefficient stored in the storage means according to the area detected by each focus detection unit. The automatic focus detection device according to item 1.