JPH03212633A - Camera provided with focus detection device - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a camera having a multi-point focus detection device that detects defocus amounts of a plurality of subject areas and performs focus detection.

[Conventional technology 1] Conventionally, as a focus detection device for a camera, a light flux from a subject area that has passed through different exit pupil areas of a photographic lens is imaged on a pair of line sensors, and the subject image is obtained by photoelectric conversion. A well-known method is to detect the amount of defocus of a subject area by determining the amount of relative positional displacement of a pair of image signals. In addition, in the above method, a focus detection system (
Many methods have also been proposed for detecting the defocus amounts of multiple object areas by preparing multiple sets of optical systems and sensors.

[Problems to be Solved by the Invention] When the defocus amount is detected for each of the plurality of areas, distance measurement will be performed for the plurality of subject areas, but it is not necessary to finally adjust the focus. is 1
In order to target the subject for the point distance measurement area, the camera side has a means for selecting the subject area from among multiple areas based on some judgment condition or manually selecting the subject area, and focuses on one of the subject areas. configured to make adjustments.

In this case, there are inconveniences such as not knowing which area is the selected area.

[Means for Solving the Problems] The present invention has been developed in view of the above-mentioned matters, and includes a display circuit that displays a display corresponding to a selected subject area, and a distance measuring operation is performed targeting the area for the photographer. It is designed to display whether the The present invention further provides that when displaying the above area, when operating the shutter release operating member, the selected area is displayed only once before the initial focus detection operation is started, and thereafter, focus is determined by repeated focus detection operations. The above-mentioned area display is performed only when the above-mentioned area is displayed, so that the display when the above-mentioned area display is executed in the finder does not bother the photographer.

In addition, the present invention further provides a method for selecting the above-mentioned area depending on whether the photographer manually selects the area or where the camera automatically selects the area.
The display format of the selection area is made different so that the photographer is informed whether the area selection was performed manually or automatically.

〔Example〕

FIG. 1 is a diagram showing a schematic configuration of a focus detection device employed in an automatic focus adjustment device according to the present invention.

In the figure, MSK is a field mask, with a cross-shaped opening MSK-1 in the center and vertical openings MSK-2 at the periphery on both sides.
, MSK-3. FLDL is a field lens and the three apertures MSK-1, MS of the field mask
Corresponding to K-2, MSK-3, three parts FLDL-
It consists of 1, FLDL-2, and FLDL-3. DP
is a diaphragm, and in the center there are a total of four openings DP-1a, DP-1b, DP-4a, and DP-4b, one pair each on the top, bottom, left, and right.
In addition, there are a pair of two openings DP-2a in the left and right peripheral areas.
, DP-2b, DP-3a, and DP-3b are provided, respectively. Each region FLDL-1, FLDL-2, FLDL-3 of the field lens FLDL has these aperture pairs DP-1, DP-4, DP-2, DP-, respectively.
3 near the exit pupil of an objective lens (not shown). AFL has 4 pairs of lenses in total, AFLla,
AFL-1b, AFL-4a, AFL-4b, AFL-
This is a secondary imaging lens consisting of AFL-2a, AFL-2b, AFL-3a, and AFL-3b, and is arranged behind each aperture of the diaphragm DP, corresponding to each aperture. SNS has 4 pairs of sensor rows 5NS-R, 5NS-C, 5NS-L, 5NS-CH
The sensor is arranged to receive an image corresponding to each secondary imaging lens AFL.

In the focus detection system shown in Fig. 1, when the focal point of the photographing lens is in front of the film plane, the subject images formed on each pair of sensor rows are close to each other, and when the focal point is behind the film plane, the subject images are close to each other. In this case, the subject images are separated from each other. This amount of relative positional displacement of the subject image has a specific functional relationship with the amount of defocus of the photographing lens, so if appropriate calculations are performed on the sensor outputs of each pair of sensor rows, the amount of defocus of the photographing lens, It is possible to detect the so-called defocus amount.

By adopting the configuration described above, it is possible to measure even objects whose light intensity distribution changes only in one direction, vertically or horizontally, near the center of the range photographed or observed by an objective lens (not shown). The peripheral openings of the field mask other than the center MSK-2, MSK
It is also possible to measure the distance to an object located at a position corresponding to -3.

FIG. 2 shows the arrangement of a focus detection device having the focus detection system shown in FIG. 1 housed in a camera.

In the figure, LNS is a zoom shooting lens, QRM is a quick return mirror, FSCRN is a focus plate, PP is a pentaprism, EPL is an eyepiece, FPLN is a film surface, SM is a submirror, MSK is a field mask, and ICF is an infrared cut. Filter, FLDL is field lens, RM
I, RM2 is the first. The second reflection mirror, SHMSK is a light shielding mask, DP is a diaphragm, AFL is a secondary imaging lens, AF
P is a prism member having a reflective surface AFP-1 and an exit surface AFP-2, and SNS is a sensor having a cover glass 5NSCG and a light receiving surface 5NSPLN. Prism member AF
P is a reflective surface AFP- on which a metal reflective film such as aluminum is deposited.
1, and has the function of reflecting the light beam from the secondary imaging lens AFL and deflecting it to the exit surface AFP-2.

SPI is a light emitting diode, LNSA is a gradient index lens array, and LNSB is a light projection lens. The light flux of the light emitting diode SPI passes through the lens array LNSA and the projection lens LNSB, is reflected at the top of the quick return mirror QRM, and then illuminates the display section on the focus plate FSCRN.

FIG. 3 is a circuit diagram showing an example of a specific configuration of a camera equipped with a focus detection device as shown in FIG. 1. First, the configuration of each part will be explained.

In FIG. 3, PH1 is a camera control device, which includes, for example, a CPU (central processing unit), ROM, RAM,
It is a one-chip microcomputer (hereinafter referred to as microcomputer) that has an A/D conversion function. Microcomputer PR3 is R
A series of camera operations such as automatic exposure control function, automatic focus adjustment function, film winding and rewinding, etc. are performed according to the camera sequence program stored in the OM. For this purpose, the microcomputer PRS uses communication signals So, SI, 5
CLK and communication selection signals CLCMC5DR and CDDR are used to communicate with peripheral circuits within the camera body and a control device within the lens, thereby controlling the operation of each circuit and lens.

SO is the data signal output from microcomputer PR3, SI
is a data signal input to the microcomputer PR3, and 5CLK is a synchronization clock for signals So and SI.

LCM is a lens communication buffer circuit, and when the camera is in operation, it supplies power to the lens power supply terminal VL, and the selection signal CLCM from the microcomputer PRS is at a high potential level (hereinafter referred to as "H") and a low potential level. is “L”
”), it becomes a communication buffer between the camera and lens.

The microcomputer PR3 sets the selection signal CLCM to “H” and
When predetermined data is sent out as a signal SO in synchronization with CLK, the buffer circuit LCM outputs 5CLK via the camera-lens communication contact.

Each SO buffer signal LCK and DCL is output to the lens. At the same time, the buffer signal of the signal DLC from the lens LNS is output as the signal SI, and the microcomputer PRS
inputs the signal SI as lens data in synchronization with 5CLK.

DDR is a switch detection and display circuit, and the signal CD
Selected when DR is “H”, 5O1SI, 5CLK
It is controlled from the microcomputer PRS using.

When there is a change in the state of the switch SWS group, the DDR
Set Q to "L" to notify microcomputer PR3 that the switch has changed.Microcomputer PR3 selects So, SI, 5CL.
K communicates a switch change state transmission command to detect the change state of the switch.

When the DDR receives the switch change state transmission command, it outputs the switch change state to the microcomputer PRS and sends the IRQ.
Return to H'.

The microcomputer PR3 performs display control by communicating display commands and display data to the DDR using So, SI, and 5CLK. When the DDR receives a display command and display data, it activates the external display member DSP and the viewfinder display driving transistors TR-L and TR according to the command.
-C, TR-R to ○N10 FF.

SWI and SW2 are switches that are linked to a release button (not shown), and when the release button is pressed in the first step, SW is activated.
I is turned on, and then SW2 is turned on at the second stage of depression. The microcomputer PR5 performs photometry and automatic focus adjustment when SWl is turned on, and uses SW2 as a trigger to control exposure and subsequently wind the film.

Note that the switch SW2 is connected to the "interrupt input terminal" of the microcomputer PH1, and even if a program is being executed when SW1 is on, an interrupt is generated by turning on SW2, and control can be immediately transferred to a predetermined interrupt program.

MTRI is for film feeding, MTR2 is for mirror up/
This is a motor for down and shutter spring charging, and forward and reverse rotation is controlled by respective drive circuits MDRI and MDR2. Microcomputer PR3 to MDRI, MDR
Signals input to 2 MIF, MIR, M2F, M2
R is a signal for motor control.

MGI and MG2 are magnets for starting the movement of the front and rear shutter curtains, respectively, and are energized by signals SMGI, 5MG2, and amplification transistors TRI and TR2, and shutter control is performed by the microcomputer PRS.

LPR3 is an in-lens control circuit, and LC is connected to this circuit LPR3.
The signal DCL input in synchronization with K is data of a command from the camera to the photographing lens LNS, and the operation of the lens in response to the command is determined in advance.

The control circuit LPR3 analyzes the command according to a predetermined procedure, and outputs the operation of focus adjustment and aperture control, the operation status of each part of the lens (driving status of the focusing optical system, driving status of the diaphragm, etc.) and various parameters from the output DLC. (Open F number, focal length, coefficient of defocus amount vs. movement amount of the focusing optical system, etc.) are output.

Therefore, once the focus adjustment command is sent from the camera, the microcomputer PR3, which is the camera control device, does not need to be involved in lens driving at all until the lens driving is completed.

The LTMR is a motor that moves the focusing optical system in the optical axis direction to adjust the focus and is controlled by a control circuit LPR3.

Further, when an aperture control command is sent from the camera, the LPR 3 drives a stepping motor DMTR, which is known for driving an aperture, according to the number of aperture stages sent at the same time. SPC is a photometric sensor for exposure control that receives light from the subject through the photographic lens, and its output is 5 sp.
c is input to the analog input terminal of microcomputer PR3, and A
/D conversion, it is used for automatic exposure control according to a predetermined program.

SDR is a drive circuit for the focus detection line sensor device SNS, and is selected when the signal C3DR is H'', and the So
, SI, and 5CLK from the microcomputer PR3.

Signal 5E given from drive circuit SDR to sensor device SNS
LO, 5ELL is the signal 5ELO from the microcomputer PR3
, 5ELL itself, 5ELO=゛L”, 5EL1=
When “L”, sensor row pair 5NS-R, 5ELO=”
H", when φ5EL1=°"L, sensor row pair 5NS-
C, 5ELO="L" When SEL 1 = "H", sensor row pair 5NS-L, 5ELO="H", 5EL
When 1="H", this signal selects the sensor row pair 5NS-CH.

After the accumulation is completed, set 5ELO and 5ELL appropriately,
Then by sending the read clock RCK, 5
The image signals of the pair of sensor rows selected by ELO and 5ELL are serially output from the output VOUT. The output VIDEO of the sensor drive circuit SDR is an image signal obtained by taking the difference between the image signal VOUT from the sensor device SNS and the dark current output, and then amplifying the difference with a gain determined by the brightness of the subject. The dark current output is an output value of a light-shielded pixel in the sensor array, and the SDR holds the output in a capacitor based on a signal from the microcomputer PR3, and performs differential amplification between this and the image signal.

The output VIDEO is input to the analog input terminal of the microcomputer PR3, and the microcomputer PR3 performs A/D conversion on the signal and sequentially stores the digital values at predetermined addresses on the RAM.

Signal TINTER, TINTEC, TIN position, TINT
ECH has sensor row pairs 5NS-R, 5NS-C,
This is a signal indicating that the charges accumulated in 5NS-L and 5NS-CH are appropriate and the accumulation has ended, and the microcomputer PR3
In response to this, the image signal is read out. The operations of the sensor drive circuit SDR and the sensor device SNS have been previously disclosed by the present applicant in Japanese Patent Application Laid-Open No. 63-216905 as a focus detection device having two pairs of sensor rows, so they will not be described here. Detailed explanation will be omitted.

As described above, the microcomputer PR3 receives the image information of the subject image formed on each pair of sensor rows, and then performs a predetermined focus detection calculation, thereby being able to determine the amount of defocus of the photographing lens.

Next, the automatic focus adjustment device for a camera having the above configuration will be explained according to the flowchart below.

FIGS. 4(a) and 4(b) are flowcharts of the main sequence of this embodiment. A description will be given below according to the flowchart.

(1) When the main switch of the camera is turned on, initial settings of the camera are performed and the main loop (step (2)) is entered.

(2) First, check whether the photometry & distance measurement switch (hereinafter referred to as 5W1) is turned on.

If SWI is ON, proceed to (13) and SWl is OF.
If F, branch to (3).

(3) Turn off the focus display (if the focus display was turned on in the past, turn it off now).

(4) Check whether the distance measurement field of view selection switch is ON or not. If ON, proceed to (5); if OFF, proceed to (6). Note that the ranging field selection switch is one of the switches SWS in FIG. 3.

(5) Enter the distance measurement field of view selection mode in which the distance measurement field of view selection switch is turned on. Distance field of view selection mode flag (SE
LECT-MODE).

(6) When the distance measurement field of view selection switch is OFF, check whether the distance measurement field of view selection mode is already entered. If the ranging field of view selection flag (SELECT-MODE) is set, proceed to (7); if cleared, proceed to (11)
Branch to.

(7) If the distance measurement field of view has been changed by the distance measurement field of view change switch, the process branches to (8). The distance measurement field of view is changed using a dial switch.

In addition to changing the distance measurement field of view, a distance measurement field of view automatic selection mode for automatically switching the distance measurement field of view is also set.

(8) When the distance measurement field of view is changed, the memory that stores the distance measurement sensor to be used is rewritten.

(9) Turn on the display in the finder (hereinafter referred to as SI display) corresponding to the distance measurement field of view used for distance measurement.

(10) Check whether the main switch of the camera is ON, and if it is ON, return to (2) and repeat the main loop. If it is OFF, camera operation will be stopped.

(11) If it is not the distance measurement field of view selection mode in (6), check the other switches, and if they are ON, proceed to (12), and if they are OFF, proceed to (10).

Since the other switches have no direct relation to the present invention, detailed explanations will be omitted.

(12) Perform processing according to the switch turned on (1
Proceed to 0).

The operations of steps (7), (8), and (9) above will be described in detail. These steps are executed in the distance measurement field selection mode as described above.

In step (7), for example, the on/off state of a switch (predetermined switch of the switch group SWS) that is turned on/off in conjunction with the rotation of an operation dial provided on the outside of the camera is determined by the microcomputer PR3 through communication between the DDR and PRS. Detected at. When the dial operation is detected in step (7), the process proceeds to step (8) as described above. In this embodiment, the sensor is the central vertical sensor 5NS-C1.
Side sensor 5NS-CH1 Left and right sensor 5NS-R, 5
NS-L is installed and has a distance measurement field of view of 3 parts (left, center, right), and every time a dial operation is detected, all the left, center, and right sensors are cyclically designated in sequence. This designated sensor will be remembered. Note that specifying all sensors means specifying automatic selection mode. In step (9), the transistors TRLTRC,T corresponding to the sensors stored in step (8) above are
In order to drive RL, communication is made from the microcomputer PR3 to the circuit DDR, and one of the light emitting diodes 5PILSPIC and 5PIL corresponding to the stored sensor is selected and lit, and the selected field of view is displayed in the finder as described later. It is assumed that when all the sensors are designated, that is, when the automatic selection mode is selected, the light emitting diodes are kept in a non-lit state.

In steps (7) to (9), the distance measurement field selected by the photographer is displayed in the finder as described above.

Next, the case where the switch SW is turned on will be explained. In this case, the process branches from (2) to (13).

(13) Clear the distance measurement field of view selection mode flag to cancel the distance measurement field of view selection mode.

(14) Turn off the SI display. As a result, the selected light-emitting diode that is lit is turned off.

(15) First step after SWI is pressed (15
) is executed. If it is the first time (1
Proceed to 6), and branch to (20) from the second time onwards.

(16) Determine whether the distance measurement field of view is specified. If the distance measurement field of view has been specified, the process proceeds to (17), and if the distance measurement field of view is in automatic selection mode, the process branches to (20).

(17) If the distance measurement field of view is designated, the SI display corresponding to the distance measurement field of view is performed in the same manner as in step (9).

(18) Wait for a certain period of time while displaying SI.

(19) After waiting for a certain period of time in (18), the SI display is turned off.

In (17) to (19), the SI is displayed for a certain period of time to display the distance measurement field of view, and is not displayed in the automatic selection mode.

(20) In the case of CALL focus detection operation and automatic selection in the AF subroutine, calculation of selection of distance measurement field of view is performed. The AF
The subroutine will be described later.

(21) Determine whether the focus detection result is in focus.

If the focus detection result is in focus, the JF flag is set in the AF subroutine, and here the JP flag is used for determination.

If the JF flag is cleared, the process proceeds to (22); if it is set, the process branches to (23).

(22) If out of focus, turn off the focus display and repeat the main loop.

(23) Determine whether or not it was in focus last time. If it was in focus last time, go to (28), and if it was out of focus last time and it is in focus this time, go to (28).
Branch to 4).

(24) Turn on the focus display. This in-focus display is executed by turning on the transistor JFTR and lighting the light emitting diode JFLED using a signal from the DDR.

(25) Turn on the SI display.

If a distance measurement field of view is specified, an SI display corresponding to the specified distance measurement field of view is performed, and in the case of automatic distance measurement field of view selection, an Sr display corresponding to the distance measurement field of view determined by the automatic selection routine is performed.

(26) Perform WAIT for a certain period of time.

(27) Turn off the Sr display.

(28) Check whether the release switch (SW2) is turned on, and if SW2 is turned on, perform a release process (not shown).

If SW2 is OFF, the main loop is repeated.

FIG. 5 is a flowchart showing the focus detection operation in step (2o) of FIG. 4(b).

The focus detection operation will be explained according to FIG.

(30) AF start.

Focus detection is performed by repeatedly executing an AF routine.

(31) Determine whether AF is the first time. If it is the first time, proceed to (32), and if it is the second time or later, branch to (36).

(32) Determine whether the distance measurement field of view is specified or whether automatic selection mode is selected. If you are in automatic selection mode, proceed to (33).
If the distance measurement field of view is specified, the process branches to (34).

(33) In the automatic ranging field selection mode, focus detection is performed with all ranging sensors.

Set flags for all sensors.

(34) If a distance measurement field of view is specified, only the flag of the distance measurement sensor corresponding to the specified distance measurement field of view is set.

(35) Clear parameters for focus detection and initialize the sensor.

(36) Call the sensor storage routine.

In this routine, the sensor signal designated by the flag (33) or (34) is stored, and after the storage is completed, the sensor signal is read while being A/D converted. Furthermore, the sensor signal is corrected and converted into data suitable for focus detection.

(37) A focus detection calculation is performed using a known calculation method from the sensor signal obtained in (36).

In this subroutine, the defocus amount of the distance measurement field of view specified is detected.

(38) Determine whether the mode is automatic distance measurement field of view selection mode.

If the distance measurement field of view is automatically selected, the process proceeds to (39), and if the distance measurement field of view is specified, the process branches to (4o) without performing (39).

(39) Call the ranging field selection routine. In the ranging field selection routine, one ranging field is selected from the calculated defocus amount according to a predetermined algorithm. As this distance measurement field of view selection algorithm, selection of the defocus amount indicating the closest subject among the defocus amounts, selection of the field of view for this defocus amount, etc. are adopted.

(40) Perform focus determination.

If the distance measurement field is specified, the defocus amount of the specified distance measurement field is displayed, or if the distance measurement field is automatically selected, the defocus amount of the selected distance measurement field is within the focusing range. A judgment is made.

(41) Branching is performed depending on the determination result of (40).

In the case of in-focus, the process proceeds to (42), and in the case of out-of-focus, the process branches to (47).

(42) When in focus, set the JF flag.

(43) Determine whether distance measurement field of view is automatically selected.

In the case of automatic selection, the process proceeds to (44), and if the distance measurement field of view is specified, the process branches to (49).

(44) Determine whether the lens mode is autofocus or manual focus. For autofocus (4
Proceed to step 5) and branch to step (46) in case of manual focus.

(45) Call the depth/white determination routine.

In this routine, if the distance measurement field is in automatic selection mode and autofocus mode is set, the difference between the defocus amount of the automatically selected distance measurement field and the defocus amount of other distance measurement fields is constant. When the value is within the threshold value, the display flag corresponding to the distance measurement field of view is turned on.

(46) Call the in-focus range determination routine.

In this routine, in the case of manual focus, it is determined whether the defocus amount of each distance measurement field of view other than the one automatically selected is within the focusing range, and the display flag corresponding to the field of view within the focusing range is turned on.

(47) Determine whether the autofocus mode is manual focus mode, and if it is in autofocus mode (
48), and when in manual focus mode, go to (4).
Proceed to 9).

(48) Call the lens drive routine.

In this routine, the lens drive amount is calculated from the defocus amount of the selected distance measurement field of view and the lens is driven.

(49) Return to the main routine.

The operations according to the steps of each flow described above are summarized as follows.

First, when the distance measurement field of view is selected manually, in this case, when the switch SWI is performed, steps (17) (18) (1)
The field of view selected in 9) is the light emitting diode 5PIL, 5
One of the PIC and 5 PIR lights up for a predetermined period of time and is displayed in the finder. After that, in the AF subroutine, the amount of defocus in the manually selected distance measurement field of view is determined, and it is determined whether or not the focus is in focus based on the amount of defocus in that field of view, and if it is out of focus, the amount of defocus is The lens is driven. Then, the focus detection operation is repeated again. During this repeated focus detection, the process proceeds from step (15) to step (20), so no SI display is performed.

When the above focus judgment determines that the focus is in focus, (42) (4
Proceed to (21) and (23) via 3). At this time, if the focus was not determined in the previous focus detection, (24) to (27)
), the focus display light emitting diode JFLED lights up, and the diode corresponding to the selected visual field lights up for a predetermined period of time. Thereafter, the above operation is repeated, but when the previous focus was in focus and the current focus is also in focus, steps (24) to (27) are not executed and no SI display is performed.

Further, in the case of manual focus mode, the above display operation is performed without the lens being driven. It is assumed that the autofocus and manual focus modes are selected by a mode setting switch provided on the lens LNS.

Next, the case of automatic selection mode and autofocus mode will be explained.

In this case, the SI display when the switch SW is turned on is not executed, and the process proceeds to the AF subroutine. The defocus amount of one predetermined field of view among the defocus amounts of each distance measurement field of view is selected in step (39), and it is determined in (41) whether or not the defocus amount of this selected field of view can be considered to be in focus. When it is determined that the focus is in focus, steps (42) (43) (44) (
45) is executed. In these steps, a visual field that exhibits a defocus amount within a predetermined value with respect to the defocus amount of the selected visual field is determined. Therefore, step (
When displaying 24) to (27), both the automatically selected visual field and the visual field showing a defocus amount close to the defocus amount of the visual field are displayed in SI for a predetermined period of time.

Next, the case where the manual mode is selected will be explained.

In this case, if the automatically selected defocus amount of the visual field is determined to be in focus, it is determined in step (46) whether the defocus amounts of the other visual fields are also in focus. Therefore, when the selected field of view is in focus, SI display will be performed for each field of view determined to be in focus.

Next, details of the SI display will be explained.

On the light incident surface side of the focusing plate FSCRH in this embodiment,
A Fresnel lens FSCRN-f is provided as shown in FIG. 8, and a light diffusing surface FSCRN-g is formed on the light exit surface side as shown in FIG. Additionally, there are three display sections AFMK-R, AFMK-C, and AFMK on the light exit surface.
-L is provided corresponding to each distance measurement field of view. Display section AFMK-R, AFMK-C.

As shown in FIG. 9, the AFMK-L each displays an area indicating a distance measurement range within the photographing screen, and is composed of a large number of prism focusing bodies. At this time, the display section AFMK-R
, AFMK-C, and AFMK-L are arranged so that the ridgeline of the prism constituting the display section is substantially orthogonal to the ridgeline direction of the Fresnel lens FSCRN-f.

As a result, the display section efficiently guides the illumination light flux (described later) to the eyepiece side through the refraction effect of the prism, and prevents ghost light generated from the ridge of the Fresnel lens from entering the eyepiece side. Good observation of the image is being carried out.

Display parts AFMK-R, AFMK-C in this embodiment,
The lighting method for AFMK-L is light emitting diode SP.
The light flux from I is sent to the quick return mirror QR via the lens array LNSA and light projection lens LNSB shown in the second diagram.
After guiding the light onto M and reflecting it by the quick return mirror QRM, the display part AFMK-R, AF of the focus plate FSCRH
A selected predetermined display section of MK-C and AFMK-L is illuminated. Then, the display unit is connected to the focus plate F.
The object image formed on the SCRN is observed through a finder system.

Figures 6 and 7 are schematic diagrams of the optical paths of the finder system and illumination system shown in Figure 2. Figure 6 is a plan view thereof, and Figure 7 is a side view of the same as seen from the side. . As shown in Figure 6, the light projection lens LNSB has three lens parts LN.
SB-R.

It is composed of LNSB-C and LNSB-L. Also, the projection lens LNSB has three areas A on the focus plate FSCRN.
FMK-R, AFMK-C.

An arbitrary area is selected from AFMK-L and illuminated. Further, as shown in FIG. 7, the projection lens LNSB illuminates the focus plate FSCRN from an oblique direction at an angle θ.

Focal plate FSCRN illuminated by floodlight lens LNSB
Upper three displays AFMK-R, AFMK-C, AFM
K-L is composed of an aggregate of many prisms,
The illumination light beam incident on each prism is refracted and guided in the direction of the eyepiece EPL. This provides a bright display.

In addition, display parts AFMK-R, AFMK-C, AFMK-L
One of the display parts is a light emitting diode 5PI-R, 5
By selectively illuminating with the PI-C, 5PI-L and the projection lens LNSB, it is possible to display the currently selected distance measurement field in red, for example, and the others in black.

By configuring the SI display system in this manner, the selected field of view or the in-focus field of view is displayed superimposed with the subject image in the finder in the above-described operation.

Figure 10 is a configuration diagram showing another example of the SI display in the finder.
LED for specifying distance measurement frame under MK-C, AFMK-L
AFLED-R, AFLED-C, and AFLED-L are provided, and these are displayed using the above-mentioned SI display operation.

FIG. 11 is a flowchart showing another example of the flowchart of the automatic focus adjustment device of the present invention shown in FIGS. 4(a) and 4(b).

The flowchart in FIG. 11 differs from the flow shown in FIG. 4(b) only in that steps (17) and (19) are added.

The operation according to this flow is almost the same as that described in FIGS. 4(a) and 4(b), but the SI display immediately after turning on the switch SW when the automatic selection mode is set is This is different from the case in Figure (b). That is, this 11th
In the flowchart of the figure, when it is determined in step (16) that the automatic selection mode is selected, steps (17)' to (19)' are executed, so that the light emitting diodes 5PIL and 5PIC are selected.

The 5PIR lights up for a certain period of time, indicating to the photographer that the camera is in automatic selection mode.

The other operations are the same as the flows shown in FIGS. 4(a) and 4(b) above, so their explanation will be omitted.

[Effect] As described above, in the present invention, the selected distance measurement field of view area is displayed twice during the release operation, and the area is displayed only when it is determined that the camera is in focus when the focus detection operation is repeated thereafter. Therefore, it is possible to display in the viewfinder which area the distance measurement is being performed on and which area is in focus without bothering the viewfinder. Furthermore, since the display form is different depending on whether the area is manually selected or automatically selected, the photographer can be informed of the selection mode in advance.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing the configuration of a focus detection device employed in a focus adjustment device according to the present invention, FIG. 2 is a configuration diagram showing the arrangement of the focus adjustment device according to the present invention housed in a camera, FIG. 3 is a circuit diagram showing an embodiment of the camera equipped with the focus detection device shown in FIG. 1; FIGS. 4 and 5 are explanatory diagrams showing flow charts for explaining the operation of the camera shown in FIG. 3; Figure 6 is a plan view showing the optical path of the finder system and illumination system shown in Figure 2 developed, Figure 7 is a side view of the development of Figure 6 seen from the side, and Figure 8 is the focus plate shown in Figure 6. , FIG. 9 is a block diagram showing the display section of the focus screen shown in FIG. 6, FIG. 10 is a block diagram showing another example of the display section in the viewfinder, and FIG. 11 is a modification of the flow shown in FIG. 4. It is an explanatory diagram showing an example. PRS...Microcomputer SNS...Sensor SPI...Light-emitting diode AT:I''1 to Kami-kita-〇AT:/'7 to 1 shaku AFLE, D C 1st /figure

Claims (4)

[Claims] (1) Focus state detection means for detecting focus states in a plurality of subject areas, designation means for designating at least one of the plurality of subject regions, and displaying the area designated by the designation means. a display means, a control means for repeatedly performing a detection operation by the detection means while the release operation member is in an operating state, and when the detection operation is performed for the first time by the detection means in response to the operation of the release operation member; A camera having a focus detection device, comprising a display control circuit that drives the display means and thereafter drives the display means when the focus state detected in the detection operation becomes a state indicating focus. . (2) The camera according to claim (1), wherein the display control circuit drives the display means for a predetermined period of time. (3) A selection circuit having focus state detection means for independently detecting focus states in a plurality of copy areas, and a manual mode for manually selecting an arbitrary area among the areas, and an automatic mode for automatically selecting an arbitrary area. and,
Display means for displaying the area selected by the selection circuit;
A focus detection device comprising a drive circuit that drives the display means before and after the detection operation by the focus state detection means in the manual mode, and drives the display means after the detection operation in the automatic mode. camera with. (4) The drive circuit is provided with a drive mode for driving all the display means for displaying each area, and in the automatic mode, the drive mode is activated before the detection operation to display all the display means. A camera having the focus detection device according to item (3).