JPH0797176B2 - Focus detection device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a focus detection device that detects a focus state based on the luminance distribution of an object in two orthogonal directions.

(Background of the Invention) Conventionally, for example, a focus detection device in a phase difference detection direction arranged in a camera is configured to detect a defocus amount of a photographing lens from a luminance distribution in only one direction of a subject. However, there is a defect that focus detection cannot be performed on a subject having no luminance distribution in that direction. In view of this point, the applicant of the present application discloses, for example, Japanese Patent Laid-Open No. 60-235822 (unpublished), for example, a vertical pair of focus detection line sensors and a horizontal pair of focus detection line sensors which are arranged orthogonally to each other. A secondary image forming lens having a pair of lens parts for forming a secondary image is arranged on the side to detect the luminance distribution in the horizontal and vertical directions of the shooting screen, and the defocus amount of the shooting lens is determined from the output of each sensor. We have proposed a device that enables detection. As a result, even if the defocus amount on one side may be uncalculated depending on the appearance and pattern of the subject at that time, the defocus amount can be obtained from the luminance distribution on the other side, and focus detection becomes impossible. It can be said that it is a very effective device.

By the way, in the apparatus of the above-described embodiment, the two pairs of line sensors, which are arranged orthogonally to each other, are located in the direction perpendicular to the optical axis of the incident light speed, and it is an accurate focus. Although it is an essential condition for detecting the state, one of the pair of line sensors due to assembly error, etc.
Alternatively, when both of them lose the relationship (when an error occurs in the longitudinal direction), it becomes impossible to accurately detect the focus state.

(Object of the Invention) It is an object of the present invention to adjust the tilt of each focus detection sensor pair even when the focus detection sensor pair is tilted with respect to a plane perpendicular to the optical axis, and to make a wrong focus state. It is an object of the present invention to provide a focus detection device capable of preventing the detection of

(Characteristics of the Invention) In order to achieve the above object, the present invention provides a first adjustment for adjusting an inclination amount of a sensor holding member with respect to a surface perpendicular to an optical axis in a direction in which one focus detection sensor pair is arranged. A second adjusting mechanism that adjusts the amount of inclination of the sensor holding member with respect to a plane perpendicular to the optical axis in the direction in which the other pair of focus detection sensors are arranged. The first and second focus detection sensor pairs are made to coincide with the plane perpendicular to the optical axis by the adjusting mechanism.

(Examples of the Invention) Hereinafter, the present invention will be described in detail based on illustrated examples.

1 to 3 show an embodiment in which the present invention is applied to a camera, and FIG. 1 is a sectional view in a state where a strobe is attached. In FIG. 1, 1 is a camera body, 2 is a lens barrel that holds a taking lens 3 movably in the direction of an optical axis 4, and 5 is a sub-mirror 6 and a subject light that has passed through the taking lens 3 and a viewfinder system and an AF. A main mirror that separates into a photometric system, 7 is a focus glass that constitutes a finder system together with a pentaprism 8 and an eyepiece lens 9,
Reference numeral 10 denotes an AF / AE sensor holding member 13, which holds a field lens 11, a secondary imaging lens 12, a sensor section 13a in which an AF line sensor and an AF sensor are arranged (details will be described later), and a sensor section. The AF / metering unit, which is an AF / metering system (here, both the TTL strobe light metering system and the AE system are called metering system), which has a TTL strobe light metering sensor 14 having 14a etc. A shutter, 16 is a strobe, 17 is a flash emitting section, 18
Is a near infrared auxiliary light emitting part for AF.

2 and 3 are detailed views of only the main part of the AF / photometric unit 10 shown in FIG. 1, FIG. 2 is a sectional view thereof, and FIG. 3 is a developed perspective view thereof.

A field mask 20, an infrared cut filter 21 having regions 21a and 21b having different transmittances, and a field lens 11 are attached in this order on the upper surface side of the main body block 19, and a diaphragm 22 and two lenses are attached on the lower surface side. Next imaging lens 12, presser spring 2
3, the sensor block 24, the sensor holder 25, and the AF / AE sensor holding member 13 are attached in this order. Further, the body block 19 is provided with a TTL at a position where the reflected light from the film surface can be received through the field lens 11.
A strobe light control sensor 14 is attached.

The diaphragm 22 has a pair of openings 22a, 22b and 22c, 22d which are provided orthogonally to each other as shown in FIG. 3, and has an arc whose radius is a point coinciding with the center A of these openings. Department
It has 22e and 22f, a spring portion 22g, and an elongated hole 22h. The secondary imaging lens 12 having the lens portions 12a to 12d is positioned by the pins 12e and 12f in a state where the diaphragm 22 having the above-mentioned respective portions is sandwiched between the main body block 19 and fixed by the pressing spring 23. (See Figure 2). In such a state, the lens portions 12a to 12d of the secondary imaging lens 12 have a positional relationship corresponding to the openings 22a to 22d (details will be described later), and the positioning portions 22e and 22f have secondary portions. Imaging lens 1
Two pins 12g and 12h are inserted into the spring portion 22g, and a pin 12i is inserted into the spring portion 22g. When the pin 12i is inserted into the spring portion 22g, the spring portion 22g is deformed as shown in FIG. 2 and a force that urges the diaphragm 22 toward the positioning portions 22e and 22f is generated. Therefore, the eccentric pin 26 is inserted into the hole of the main body block 19 through the elongated hole 22h of the diaphragm 22 and rotated to rotate the diaphragm 22 by a small angle about the center A of each opening of the diaphragm 22 ( 2 direction of arrow B) becomes possible.

The sensor block 24 and the sensor holder 25 are arranged under the secondary imaging lens 12 as described above, and these are arranged together with the relay screw 27, the washer 28, and the eccentric pin 29 under the AF. A tilt adjusting mechanism for the AE sensor holding member 13 is formed. The AF / AE sensor 13 is a sensor holder
The sensor holder 25 is adhered to the mounting surface 25a of 25, and is fixed to the arc-shaped mounting surface 24c of the sensor block 24 having the mounting holes 24a and 24b by the mounting screw 27 and the washer 28 via the mounting hole 24a.

Here, since the center R of the arcuate mounting surface 24c is the axis C drawn on the assumption in FIG. 2 and the mounting hole 24a of the sensor block 24 is a long hole, the direction of arrow D in FIG. The tilt can be adjusted. Further, the sensor holder 25 is fixed to the sensor block 24 by an eccentric pin 29 via a mounting hole 24b which is a long hole similar to the mounting hole 24a, and the bending portion 25b of the sensor holder 25 has a sufficiently thin wall thickness. Since it has flexibility, it is possible to adjust the inclination in the direction of arrow F in FIG. 2 by rotating the eccentric pin 29 about the axis E drawn on the assumption in FIG.

In the AF / metering unit 10 with the above structure,
Each of the TTL strobe light control system, AF system, and AE system will be described below.

First, a TTL strobe light control system (abbreviated as a light control system in the following embodiments) will be described. The dimming system is for taking in the reflected light on the film surface at the time of stroboscopic photography by the field lens 11 to the sensor section 14a of the dimming sensor 14 and stopping the light emission of the strobe 16 depending on the amount of received light. That is, the main mirror 5 and the sub-mirror 6 move up, the front curtain of the shutter 15 runs, and the flash is exposed when the film is exposed.
When 16 emits light, a subject image is formed on the film, and its reflected light is generated. Part of the reflected light is the AF shown in Fig. 2.
・ Field mask 20 of photometric unit 10, infrared cut filter 2
1 that has passed through 1 and the field lens 11 and is incident on the sensor unit 14a of the dimming sensor 14, and for example, the amount of received light has reached the photometric amount previously obtained by the AE sensor that performs spot photometry described later. Is detected by a microcomputer described later, a light emission stop signal is output to the strobe 16 side, and light emission is stopped.

As can be seen from the above, since the field lens 11 used for AF and AE systems is shared with the TTL dimming system, the film sensitivity distribution is good while the camera is compact and low cost is realized. It can be anything.

Next, the AF system will be described. 4 and 5 are optical path development diagrams of the AF system. The secondary imaging lens 12 has a pair of lens portions 12a, 12b and 12c, 12d arranged orthogonally as shown in FIG.
FIG. 4 shows a cross section including the optical axes of the lens portions 12a and 12b among them, and the lens portions 12c and 12d.
FIG. 5 shows a cross section including the optical axis of. Here, for simplification of the drawing, only a light beam having an object height of 0 on the primary imaging plane passing through the center of each aperture of the diaphragm 22 is drawn, and the position of the arrow G in the drawing is the primary imaging. Surface, arrow H is sensor
It is the sensor surface of 13a. Lens part 12a of the secondary imaging lens 12
.. to 12d correspond to the openings 22a to 22d of the diaphragm 22 as described above, thereby forming four secondary images on the sensor portion 13a, and the boundaries between these secondary images are the field masks. It is separated by 20 aperture images. The distance between the openings 22a and 22b, which form a pair and have the same shape, of the diaphragm 22 is equal to the distance between the openings 22c and 2c.
It is narrower than the interval of 2d, and these openings are projected onto the pupil of the imaging lens 3 by the field lens 11. This is shown in FIG. In the figure, 31 is an exit pupil of the taking lens 3, and 31a to 31d are areas on the pupil plane corresponding to the openings 22a to 22d of the diaphragm 22, respectively. In the case of a general camera taking lens, the areas M and N are F
It should be 4, F8 or so.

FIG. 7 shows a state of a secondary image on the sensor portion 13a of the AF / AE sensor holding member 13. On the sensor 13a, line sensors SAA, SA for AF that perform vertical distance measurement and horizontal distance measurement
B and SAC, SAD and two AE sensors SAE, SAF are arranged adjacent to the line sensors SAA, SAB (to sandwich the distance measuring area), and secondary images 32a to 32d are formed on the two sensors AE, SAF. Next imaging lens 12
Projected by. The secondary images 32a and 32b are subject images formed by the light fluxes passing through the regions 31a and 31b on the pupil of the taking lens 3, and the secondary images 32c and 32d are subject images formed by the light fluxes passing through the regions 31c and 31d. The broken lines 32e and 32f are the sub-mirror 6.
This is the image area that will be missed by. In addition, the sensor unit 13
33a to 33d arranged on a are the line sensors SAA to
In the SAD sensor drive circuit, a light-shielding aluminum layer is formed on this portion so that the light incident on this portion does not affect the sensor output.

FIG. 8 is an explanatory diagram of the defocus amount calculation, in which the outputs of the line sensors SAA to SAD are represented as images A to D, respectively. As described in FIG. 6, the A and B images are the area 31 on the pupil.
The C and D images are formed by the light fluxes that have passed through a and 31b, while the C and D images are formed by the light fluxes that have passed through the outer regions 31c and 31d. The image is larger than the A and B images. That is, in FIG. 8, X ₂ is larger than the phase difference X ₁ . This phase difference
The X ₁ and X ₂ information is transmitted to the microcomputer to be described later via the sensor drive circuits 33a to 33d, where the defocus amount is calculated and the focus control of the photographing lens 3 is executed. , When performing distance measurement with both line sensors SAA, SAB and SAC, SAD, the calculation result from C and D images has a larger image shift amount, so using this result is the focus detection The accuracy is high.

FIG. 9 is a diagram showing a distance measuring area within the viewfinder field of the camera. In the drawing, 34 is a viewfinder field of view of the camera, 35 is a view drawn assuming a distance measurement area in the viewfinder field 34, and the horizontal distance measurement area is a line sensor SAA,
Back projection image of SAB, vertical distance measuring area is line sensor SA
It agrees with the back projection image of C and SAD. The actual distance measuring area 35 is written as a figure on the focus glass 7 shown in FIG.

FIG. 10 shows a state of the AF / AE sensor 13 on the sensor 13a when the secondary imaging lens 12 has a manufacturing error. That is, as shown in FIG. 11 (a), the ideal positional relationship of each lens portion in the secondary imaging lens 12 is
It is assumed that an error (with respect to each of the openings 22a to 22d of the diaphragm 22) occurs as shown in FIG. 11 (b). In this way, when the right angles of the lens portions 12a, 12b and 12c, 12d are not shown, the right angles of the secondary images 32a, 32b and 32c, 32d also become worse as shown in FIG.
Therefore, the line sensors SAA, S for the secondary images 32a, 32b are
If the positions of AB are aligned, on the other hand, the alignment of the line sensors SAC and SAD with respect to the secondary images 32c and 32d becomes impossible. As a result, different parts of the subject are projected onto the line sensors SAC and SAD, and the 12th area is
As shown in the figure, when a subject image with a luminance pattern with diagonal lines is incident (when there is no manufacturing error, a subject image with a luminance pattern with diagonal lines is incident on the same pixel), a focusing error occurs. It occurs, and it is inconvenient as it is. Therefore, in such a case, the diaphragm 22 is rotated in the direction of arrow B in FIG. 3 to align the secondary images 32c and 32d with the line sensors SAC and SAD.

FIG. 13 is a diagram for assisting the above description (positioning), and this diagram is a view of the secondary imaging lens 12 in FIG. 5 viewed from the direction of arrow I. In the figure, J is the secondary image forming surface of the lens portions 12c and 12d, and thus the image forming surfaces of the lens portions 12c and 12d are AF / AE.
Which is located behind the sensor surface H of the sensor 13 for
A defocused image is projected on top. On the other hand, the lens part
The image forming planes of 12a and 12b coincide with the sensor plane H, and focused images are projected on the line sensors SAA and SAB. In other words, the image forming surfaces of the lens portions 12a and 12b are aligned with the sensor surface H, and the image forming surfaces of the lens portions 12c and 12d are rearward so that the correction due to the manufacturing error of the secondary image forming lens 12 can be performed. A defocused image is projected on a position, that is, on the sensor surface H. In the figure, K is the axis determined by the lens portions 12a and 12b, L is the axis of the lens portion 12c, u is the distance from the position of the diaphragm 22 to the sensor surface H, and v is the secondary from the sensor surface H. It is the distance to the image plane J.

Here, when the axis L of the lens portion 12c is decentered by δ, if the image position shift on the secondary imaging plane J occurs by ε, then the secondary imaging magnification is β and ε = δ (1 + β) (1) The following relationship stands. At this time, the shift of the image position on the sensor surface H is α (= ε · u / (u + v)). This deviation α
Image is defocused, the apertures 22c and 22
It can be changed by moving the position of d. Therefore, if the image displaced by ε on the secondary imaging plane J is adjusted so as to intersect the axis K on the sensor surface H, it is assumed that the subject image having the oblique line shown in FIG. 12 is incident. However, the focusing error will disappear, and for that purpose the aperture 22c of the diaphragm 22
Should be moved by c, and this moving amount c can be obtained by the following equation. That is, the movement amount c is set to the distance
Expressing u, v, decentering amount δ, and secondary imaging magnification β, ε / v = c / u c = u · ε / v (2) From the above equations (1) and (2), c = uδ (1 + β) / v (3) It is possible to move the diaphragm 22 (openings 22c, 22d) by the movement amount c obtained from the above equation by rotating the eccentric pin 26 shown in FIGS. At this time, the other secondary images 32a and 32b are not affected by the rotation of the diaphragm 22 because the focused image is formed on the sensor surface H. Temporarily, due to manufacturing error, the sensor unit 13
Even if the position of a in the optical axis direction is misaligned, the secondary images 32a, 32b
Since the openings 22a and 22b of the diaphragm 22 forming the aperture are located inside (relative to the openings 22c and 22d), the movement of the opening due to the rotation of the diaphragm 22 is relatively small, and the image position due to the movement is small. The deviation of is also a very small amount.

FIG. 14 is a diagram for explaining the focus detection error amount when the sensor unit 13a is arranged inclined with respect to the optical axis. In the figure, the horizontal axis indicates the distance measuring point in the distance measuring field of view, and the vertical axis indicates the focus detection error amount. The direction of the arrow D or the axis of the sensor unit 13a around the axis C shown in FIG. A parameter is the inclination θ around the E in the arrow F direction due to an assembly error or the like. When the sensor portion 13a is tilted with respect to the optical axis, that is, when the line sensors SAA, SAB or SAC, SAD are substantially tilted in their respective longitudinal directions,
Since a focus detection error occurs, the tilt in the direction of arrow E corresponds to the error in the horizontal distance measuring field of view, and the tilt in the direction of arrow F corresponds to the error in the vertical distance measuring field. These tilt adjustments are the second,
It can be adjusted by the adjusting mechanism described in FIG.
In this way, the fact that the focusing error amount with respect to the position within the distance measuring field changes according to the inclination of the sensor means that the inclination or decentering of the secondary image lens 12 causes the change of the focusing position within the distance measuring field. Also, it is shown that this can be corrected by adjusting the inclination of the sensor.

Next, the AE system will be described. AE sensors SAE and SAF are number 7
As described with reference to the drawing, the light beams that are arranged adjacent to the line sensors SAA and SAB and have passed through the openings 22a and 22b of the diaphragm 22, that is, the regions 31a and 31b on the exit pupil shown in FIG.
The aperture image of the field mask 20 (the subject image that has passed through the aperture shape) is projected by the light flux that has passed through. Therefore, the combined photometric area of the AE sensors SAE and SAF is the first
5 The spot shape shown in Fig.
Inside the line sensor SA from the aperture image of the field mask 20
Excluding the rectangular area 35c corresponding to A and SAB (15th
Areas indicated by 35a and 35b in the figure). Since the area of the rectangular area 35c is quite small, it can be almost regarded as the aperture shape of the visual field mask 20 as the photometric sensitivity distribution, and therefore the exposure time control is performed based on the value measured by this photometric area during spot photometric photography. That is, the shutter 15 and the diaphragm control (not shown) are controlled by the microcomputer described later.

By the way, in the present embodiment, the dimming system, the AF system, and the AE system share the optical path, but as described above, the wavelength range of the light incident on each sensor needs to be limited for each system. . In other words, it is desirable for the dimming system and the AE system to match their spectral sensitivity characteristics with the spectral sensitivity characteristics of the film.
The system must be sensitive to near infrared light, for example, because near infrared fill light is used for low brightness objects. Even if the near-infrared auxiliary light is not used,
Since it is desired to capture as much light as possible (increase the ranging accuracy), it is desirable to have sensitivity up to near infrared light. Generally, a sensor is sensitive to light with a wavelength of 1000 nm or more, so it is necessary to cut infrared light with an optical filter.

FIG. 16 is a diagram showing an infrared cut filter 21 capable of achieving the above requirement, and 36a and 36b shown in the figure are A
An effective part in the E system and 37 are effective parts in the dimming system. The infrared cut filter 21 is composed of two regions 21a and 21b having different spectral transmittance characteristics. The region 21a has the characteristic shown in FIG. 17, and the region 21b has the characteristic shown in FIG. . That is, the infrared cut wavelength of the region 21a is 700 nm,
The infrared cut wavelength of the region 21b is 740 nm. 16th
As shown in the figure, the effective parts of the dimming system and AE system are located over two areas, but in both cases the area 21a occupies a smaller proportion than the area 21b, so the spectral sensitivity characteristics of the film. It is possible to perform photometry with characteristics close to (400-700 nm). On the other hand, the effective portion of the AF system is configured so as to be completely included in the area 21a so as to change from the shape of the area 21a, and consideration is given so that there is no illuminance unevenness on the line sensor surface.

FIG. 19 is a block diagram showing an outline of a main part of the single-lens reflex camera having the above structure. Reference numeral 101 denotes a control circuit for controlling various operations of the camera, which is, for example, a 1-chip microcomputer in which a CPU (central processing unit), RAM, ROM, EEPROM, input / output ports, etc. are arranged.
A series of control software and parameters including AF and metering control are stored in M and EEPROM. 102 is a data bus, 103 is data received from the control circuit 101 via the data bus 102 while the control signal 104 is being input, and the traveling control of the front curtain and the rear curtain of the shutter 15 is performed based on the data. A shutter control circuit for performing 105, 105 receives a data input via the data bus 102 while the control signal 106 is input, and an aperture control circuit for controlling an aperture mechanism (not shown) based on the data, 107 a control signal A lens control circuit that receives data input via the data bus 102 while 108 is input and controls the position of the photographing lens 3 in the optical axis 4 direction based on the data. 109 is a TTL strobe light control circuit including the light control sensor 14 and the like,
Further, 110 is an AE photometric circuit composed of the AE sensors SAE, SAF, etc., and the photometric signal photoelectrically converted by these is sent to the control circuit 101, and the shutter control circuit 103 and It is used as data for controlling the aperture control circuit 105 and strobe 16.

Reference numeral 33 denotes the two sets of line sensors SAA.SAB and SAC, SA which are CCDs in accordance with the signals input from the control circuit 101.
8 is a sensor drive circuit for controlling D described in FIG. 7.

Next, a series of shooting operations will be briefly described. When the first stroke of the release button (not shown) is performed, the photographing lens
3, the light flux that has passed through the main mirror 5, the sub mirror 6, the field lens 11, the secondary imaging lens 12, etc. is incident on the AE sensors SAE, SAF, and the photometric signal photoelectrically converted from the photometric circuit 110, that is, the subject brightness. Information is sent to the control circuit 101.

Almost at the same time, the control circuit 101 obtains the phase differences X ₁ and X ₂ between the A image and the B image and between the C image and the D image (here, it is assumed that the aperture is F4 or more. The line sensor SA on which the subject image is incident is driven through the same optical path via the sensor drive circuit 33. The respective operations of the control circuit 101, the sensor drive circuit 33, and the line sensor SA at this time will be briefly described. When the accumulation start signal STR is generated in the control circuit 101, the sensor drive circuit 33 outputs a clear signal CL to the line sensor SA. Then, the charges of the photoelectric conversion units of the line sensors SAA, SAB and SAC, SAD are cleared. Then the line sensor
SA starts photoelectric conversion and charge accumulation operation of the image projected by the secondary imaging lens 12 arranged in the previous stage. After a lapse of a predetermined time from the start of the operation, the sensor drive circuit 33 outputs the transfer signal SH to the line sensor SA, and transfers the electric charge accumulated in the photoelectric conversion unit to the CCD unit.
At the same time, the sensor drive circuit 33 outputs an accumulation end signal END to the control circuit 101, and the control circuit 101 outputs the CCD drive clock C
Wait for K to type. When the CCD drive clock CK is input, the sensor drive circuit 33 generates CCD drive signals φ ₁ and φ ₂ , and outputs the signals to the line sensor SA. When the CCD drive signals φ ₁ and φ ₂ are input, the line sensor SA outputs the analog image signal SSA to the control circuit 101 according to this signal. Thus, the control circuit 101 to analog image signal is A / D converted in synchronization with the CCD driving clock CK, a phase difference X ₁ by a known calculation method to obtain the image signal A (i) ~D (i) , X 2 That is, the focus detection signal is calculated and the data is output to the lens control circuit 107. In response to this, the lens control circuit 107 controls the taking lens 3 by a known driving method.

Next, when the second stroke of the release button is performed, the main mirror 5 and the sub mirror 6 are raised, the front curtain of the shutter 15 runs, and the strobe 16 starts to emit light. As a result, the strobe light is reflected on the subject surface, the reflected light passes through the taking lens 3 and is incident on the film, so that the subject image is started to be imprinted on the film. Further, a part of the light flux incident on the film in this way is reflected on the film surface and is incident on the dimming sensor 14 via the field lens 11, and the photometric signal received here and photoelectrically converted is the TTL strobe dimming. Circuit 109
Is output to the control circuit 101. Then, the control circuit 101
Compares the photometric information from the previous photometric circuit 110 and the photometric information from the TTL strobe light control circuit 109, and detects that they match, that is, when it detects that the proper exposure has been reached, via the shutter control circuit 103. The rear curtain of the shutter 15 is run. After that, the film is wound up, and a series of photographing operations is completed.

According to the present embodiment, the cylindrical surface 24c whose axis is in the direction orthogonal to both the direction of the pair of line sensors SAA and SAB and the optical axis.
By providing the bent portion 25b that bends in the direction orthogonal to both the direction of the other pair of line sensors SAC and SAD and the optical axis, the following effects can be obtained.

1) Inclination can be adjusted independently for each of the horizontal distance measuring unit and the vertical distance measuring unit, and a focus detection error due to tilting can be eliminated.

2) This mechanism can be realized with an extremely small number of constituent parts. This allows it to be installed in the lower part of the camera.

(Effects of the Invention) As described above, according to the present invention, the first adjustment for adjusting the inclination amount of the sensor holding member with respect to the plane perpendicular to the optical axis in the direction in which one focus detection sensor pair is arranged. A second adjusting mechanism that adjusts a tilt amount of the sensor holding member with respect to a plane perpendicular to the optical axis in a direction in which the other pair of focus detection sensors are arranged side by side. Since the one and the other focus detection sensor pairs are made to coincide with the plane perpendicular to the optical axis by the adjustment mechanism of, the respective focus detection sensor pairs are inclined with respect to the plane perpendicular to the optical axis. Even in the case, the inclination can be adjusted, and it is possible to prevent an incorrect focus state from being detected. In addition, even if a distance measurement error that depends on the image position in the distance measurement field occurs due to the eccentricity of the AF optical system components caused by manufacturing errors, etc., this distance measurement is performed by adjusting the tilt of the focus detection sensor pair. The error can be corrected.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment in which the present invention is applied to a camera, FIG. 2 is a sectional view of the AF / photometric unit shown in FIG. 1, and FIG. 3 shows the structure of the AF / photometric unit. FIG. 4 is a development perspective view for explaining, FIG. 4 is a development view of one optical path of the AF system in the AF / photometry unit, FIG. 5 is a development view of the other optical path of the other AF system, FIG. 6 is an explanatory view of pupil area division, and FIG. The figure is first
FIG. 8 is a diagram for explaining the relationship between the AF / AE sensor and the secondary image shown in the figure, FIG. 8 is a diagram for explaining the image signal used when the defocus amount is calculated, and FIG. 9 is a distance measurement area in the viewfinder field. And FIG. 10 are views for explaining the relationship between the sensor unit and the secondary image when the secondary imaging lens shown in FIG. 1 has a manufacturing error, and FIG. 11 (a) shows no manufacturing error. A plan view showing an ideal secondary imaging lens, FIG. 11 (b) is a plan view showing a secondary imaging lens having a manufacturing error, and FIG. 12 is FIG. 11 (b).
FIG. 13 is a diagram for explaining an unfavorable subject image when the secondary imaging lens of FIG. 11 is used, and FIG. 13 shows a secondary image and a line sensor when the secondary imaging lens of FIG. 11 (b) is used. FIG. 14 is a diagram for explaining the position adjustment amount, FIG. 14 is a diagram for explaining the focus detection error amount when the sensor unit shown in FIG. 2 is arranged inclined with respect to the optical axis, and FIG. 15 is for the viewfinder field of view. 16 shows a photometric area in FIG. 16, FIG. 16 is a top view showing each region of the infrared cut filter shown in FIG. 2, and FIGS. 17 and 18 are spectral transmission characteristic diagrams in each region of the infrared cut filter, FIG. 19 is a block diagram showing the outline of an embodiment of the present invention. 3 ... Camera, 5 ... Main mirror, 6 ... Sub mirror, 10
…… AF / metering unit, 11 …… field lens, 12…
… Secondary imaging lens, 13… AF / AE sensor member, 13a…
… Sensor, 14 …… TTL strobe light control sensor, 33 ……
Sensor drive circuit, 101 ... Control circuit, 109 ... TTL strobe light control circuit, 110 ... Photometric circuit, SAA-SAD ... Line sensor, SAE, SAF ... AE sensor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Koyama 770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Canon Inc. Tamagawa Plant (72) Ichiro Onuki 770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Canon Inc. Tamagawa Plant (56) Reference JP-A-58-139131 (JP, A) US Patent 4555169 (US, A)

Claims (1)

[Claims] 1. An objective lens, two pairs of focus detection sensors arranged orthogonally on a sensor holding member, and an object image formed on each of the two pairs of focus detection sensors by the objective lens. And a first adjusting mechanism for adjusting the amount of inclination of the sensor holding member with respect to a plane perpendicular to the optical axis in the direction in which one focus detection sensor pair is arranged. A focus detection device including a second adjustment mechanism that adjusts an inclination amount of the sensor holding member with respect to a plane perpendicular to the optical axis in a direction in which the other pair of focus detection sensors are arranged.