JPH10288735A - Focus detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a correction value without storing correction values for respective areas by computing the correction value with respect to a prescribed area by making two parameters expressing the position of the prescribed area of a sensor part variables of the computation. SOLUTION: A correction value arithmetic means 13 calculates a correction value C by using parameters of two or more corresponding to an area where a focus detection is to be performed. The correction value C is calculated by making coordinates x, y of the center of this area in which the center of a focus detectable area is made an origin parameters. A camera control means 14 performs a computation by using the focus deviation amount D calculated by a focus detecting means 12 and the correction value C calculated by the correction value arithmetic means 13 to calculate a corrected focus detection signal Dc. The signal Dc is transmitted to a lens control means 5 as it is or after being converted into a lens driving quantity. The lens control means 5 adjusts the focusing state of an photographing lens 1 by moving all or one part of lenses constituting a photographing optical system 2 while controlling a driving device 3 based on a received signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a focus detection system of a photographing device such as a camera and a video, or various observation devices. More specifically, the present invention relates to a focus detection device that enables two-dimensional and continuous focus detection over a wide range on a photographing screen or an observation screen.

[0002]

FIG. 8 shows an example of a conventional camera in which a focus detection device is incorporated. In the figure, reference numeral 101 denotes an objective lens for photographing, 102 denotes a semi-transparent main mirror, 1
03 is a reticle, 104 is a pentaprism, 105 is an eyepiece, 106 is a submirror, 107 is a film,
Reference numeral 8 denotes a focus detection device.

In FIG. 1, light from a subject (not shown) passes through an objective lens 101, is reflected upward by a main mirror 102, and forms an image on a focusing screen 103. The image formed on the reticle 103 is reflected by the pentaprism 104 a plurality of times and is visually recognized by a photographer or an observer via the eyepiece 105.

On the other hand, from the objective lens 101 to the main mirror 10
A part of the light beam reaching the second mirror 10 is a semi-transparent main mirror 10.
2 and is reflected downward by the sub-mirror 106 and guided to the focus detection device 108.

FIG. 9 shows the objective lens 101 and the focus detection device 108 in FIG. 8 for explaining the principle of the focus detection device.
FIG. 2 is a diagram showing only main components developed by extracting only the main components.

In the focus detection device 108 shown in FIG.
09 is a field mask arranged near the planned focal plane of the objective lens 101, ie, a plane conjugate with the film plane; 110 is a field lens also arranged near the planned focal plane;
111 is a secondary imaging system composed of two lenses 111-1 and 111-2, and 112 is two lenses 111-1 and 111-2.
-2, a photoelectric conversion element including two sensor rows 112-1 and 112-2 arranged behind the sensor array 113, and a sensor array 113 corresponding to the two lenses 111-1 and 111-2. A stop having two openings 113-1 and 113-2, and 114 is a divided two regions 114-1 and 114.
The exit pupil of the objective lens 101 including -2 is shown.

The field lens 110 has an aperture 113
Are formed in the vicinity of the regions 114-1 and 114-2 of the exit pupil 114 of the objective lens 101, and the respective regions 114-1 and 114-2 are formed.
The light fluxes 115-1 and 115-2 that have passed through 2 form light quantity distributions in the two sensor rows 112-1 and 112-2, respectively.

[0008] The focus detection principle of the focus detection device shown in FIG. 9 is generally called a phase difference detection method, and the image forming point of the objective lens 101 is located on the front side of a predetermined focal plane, that is, on the objective lens 101 side. In some cases, two sensor rows 112-
1 and 112-2, the light amount distributions formed on the respective lenses become closer to each other. On the contrary, when the image forming point of the objective lens 101 is located behind the expected focal plane, that is, on the opposite side of the objective lens 101, 2 is reached. Sensor rows 112-1, 112-2
The light amount distributions formed on each of them are separated from each other. Moreover, two sensor rows 112-1 and 112-2
The deviation amount of the light quantity distribution formed above has a certain functional relationship with the defocus amount of the objective lens, that is, the focal point deviation amount. Can be detected.

The focus detecting device shown in FIG.
The focus detection can be performed only on an object existing in one central area of the range to be inspected or photographed by 1. On the other hand, the present applicant has disclosed a focus detection device capable of detecting a focus even on an object existing at a position other than the center of a range to be observed or photographed.

FIG. 10 is a diagram showing the configuration of the optical system. In the figure, reference numeral 116 denotes a field mask, which has a cross-shaped opening 116-1 in the center and a vertically long opening 116- in the peripheral portions on both sides.
2,116-3.

Reference numeral 117 denotes a field lens, and three openings 116-1, 116-2, 116-3 of the field mask.
Corresponding to the three parts 117-1, 117-2, 117
-3. Reference numeral 118 denotes an aperture, and four apertures 118-1a and 118 are provided at the center in a pair at the top, bottom, left and right.
-1b, 118-1c, 118-1d, and a pair of openings 118-2a, 118-2b and 118-3a, 11 in the left and right peripheral portions.
Peripheral openings 118-2 and 118-3 having 8-3b are provided, respectively. The field lens 117
The regions 117-1, 117-2, and 117-3 are respectively formed by these openings 118-1, 118-2, and 118-3.
Has an action of forming an image near the exit pupil of the objective lens (not shown). 119 has four pairs of eight lenses 119-1a,
119-1b, 119-1c, 119-1d, 119-
An optical member integrating a secondary imaging system consisting of 2a, 119-2b, 119-3a, and 119-3b.
8 for each of the openings. 12
0 is a total of eight sensor rows 120-1a, 120-
b, 120-1c, 120-1d, 120-2a, 12
A photoelectric conversion element composed of O-2b, 120-3a, and 120-3b is arranged so as to receive the image corresponding to each lens of the secondary imaging system.

FIG. 11 shows a state of an image formed on the photoelectric conversion element 120. 121-1a, 121
-1b, 121-1c, and 121-1d are an opening 116-1 at the center of the field mask and a center 1 of the field lens.
The luminous flux transmitted through 17-1 is transmitted through aperture 118-1a, 1 of the aperture.
After being regulated by 18-1b, 118-1c, and 118-1d, the lenses 119-1 and 11 of the secondary imaging system behind them are regulated.
9-1b, 119-1c, and 119-1d indicate image areas formed on the photoelectric conversion element 120, respectively. Reference numerals 121-2a and 121-2b denote openings 116-2 around the field mask and the peripheral portion 1 of the field lens.
The luminous flux transmitted through 17-2 is transmitted through aperture 118-2a, 1 of the aperture.
FIG. 14 shows an image area formed on the photoelectric conversion element 120 by the lenses 119-2a and 119-2b of the secondary imaging system after being regulated by 18-2b. Similarly, reference numerals 121-3a and 121-3b denote openings 116-3 around the field mask and peripheral parts 117- around the field lens.
3 pass through the apertures 118-3a, 118- of the diaphragm.
3B shows an image area formed on the photoelectric conversion element 120 by the lenses 119-3a and 119-3b of the secondary image forming system after being regulated by 3b.

The focus detection principle of the focus detection device shown in FIG. 10 is the same as that shown in FIG. 9, and detects the relative position of the pair of sensors in the column direction. By focusing on not only the vicinity of the center of the range observed or photographed by the objective lens (not shown) but also the object located at the position corresponding to the openings 116-2 and 116-3 around the field mask. Detection can be performed. In addition, according to the present focus detection device, it is possible to perform focus detection even for an object whose light amount distribution changes only in one direction in the vertical or horizontal direction near the center.

When these focus detection devices are used in a camera such as a single-lens reflex camera whose photographing lens is replaceable, if the lens is controlled based on a focus state detection signal relating to a directly obtained defocus amount, an appropriate focus can be obtained. You may not get the status. The main reason is that the luminous flux of the objective lens forming an image to be observed or photographed and the luminous flux captured by the focus detection device are generally different.

Further, in the focus detection device of the phase difference detection system, the focus position or the defocus amount, which should be originally determined by the vertical (optical axis) aberration amount, is converted into an image shift related to the horizontal aberration. Therefore, if the objective lens has an aberration, a difference may occur between the two depending on the state of the aberration correction.

In order to solve such a problem, a correction value C unique to each objective lens is used to correct, for example, a focus detection signal D indicating the amount of defocus by Dc = D−CＤ (1). There is also known a device that includes a correction unit and controls the lens based on the obtained corrected focus detection signal Dc.

[0017]

Since the correction value C unique to each lens generally depends on the position of the focus detection area of the focus detection device, it has a focus detection area other than the center as shown in FIG. In such a case, it is necessary to have a correction value corresponding to each area. However, when the number of assumed focus detection areas is large, a large storage capacity is required to have correction values for all the detection areas on the objective lens side or the camera side.

If a photographing system such as a single-lens reflex camera and an interchangeable lens that swallows a certain position or a certain number of focus detection areas already exists, a focus different from the position or the number of the focus detection areas is used. Many new cameras equipped with detection devices will not function properly in this system.

One method for solving such a problem is disclosed in JP-A-6-331886. This is based on the assumption that the correction value C depends only on the distance l from the center of the focus detection area, and that the change can be represented by a function related to l, and the correction for two or more focus detection areas at a specific position is performed. The correction value of the focus detection area at another position is complemented by a function of, for example, a linear expression or a quadratic expression, and the correction value is obtained.

However, in the above method, since it is assumed that the correction value C depends only on the distance l from the center of the focus detection area, the focus detection means for detecting the focus of each area is different, and the output signal is different. If there is no continuity or correlation between the two, or if the focus detection means has no axial symmetry with respect to the objective lens and the optical axis, it becomes difficult to accurately obtain the correction value C.

It is an object of the present invention to solve such a problem and realize accurate correction of a focus detection signal without requiring a large storage capacity even when the number of assumed focus detection areas is large. Is what you do.

[0022]

According to the first aspect of the present invention, there is provided a sensor section having a light receiving area disposed on a two-dimensional axis for receiving a light beam having passed through an objective lens, and an output in a predetermined area of the sensor section. In a focus detection device that detects a focus state in accordance with a correction value, a correction value for the predetermined area is calculated by using two parameters indicating the position of the predetermined area of the sensor unit as a calculation variable. The above correction values can be obtained without having to store all the correction values.

According to a second aspect of the present invention, as the configuration for obtaining the correction value according to the first aspect, the correction values in a plurality of areas of the sensor unit are each used as a parameter indicating the position of each area as a calculation variable. You can ask for it.

According to a third aspect of the present invention, as the configuration for obtaining the correction value according to the first aspect, data representing coordinates relating to the position of each area in the sensor section is used as the parameter.

According to a fourth aspect of the present invention, in the configuration for obtaining the correction value according to the first aspect, the area of the sensor section which receives the light beam from the optical axis of the objective lens is set as the center coordinate, and the coordinates of other areas are set. Values are used as the parameters.

According to a fifth aspect of the present invention, as the configuration for obtaining the correction value according to the first aspect, the correction value is calculated by a function using predetermined data as a coefficient and the parameter as a variable. It is.

According to a sixth aspect of the present invention, as a configuration for obtaining the correction value of the first aspect, data for calculating the correction value is stored in a lens device mounted on a camera, and the correction value is stored in the lens device. The stored data is communicated to the camera, and a correction value is calculated in the camera using the data and the parameter.

According to a seventh aspect of the present invention, predetermined coefficient data is provided as the data of the sixth aspect, and the correction value is calculated by a function using the data as a coefficient and the parameter as a variable. Things.

According to the eighth aspect of the present invention, as a configuration of the focus detection of the first aspect, a signal related to a focus state is obtained by an output in each area of the sensor section, and a correction value in the area is used to obtain a signal related to the focus state. The purpose is to detect the focus state in the area.

According to a ninth aspect of the present invention, for a predetermined area on a predetermined focal plane of the objective lens, a focus state detecting means for obtaining a signal relating to a focus state of the objective lens, and the predetermined focal plane of the predetermined focal plane are provided. By a predetermined arithmetic processing including two or more parameters set corresponding to the position of the region,
Correction signal forming means for obtaining a signal related to correction for the area, and detecting a focus state in the area based on the signal related to the focus state and the signal related to correction,
It is an object of the present invention to provide a focus detection device which can obtain a correction value in each area without storing a correction value for each area.

According to a tenth aspect of the present invention, in the ninth aspect, each of the focus detecting devices includes a sensor unit having a plurality of light receiving regions arranged on a two-dimensional axis for receiving a light beam passing through an objective lens. A signal related to the correction for each area is obtained by an operation using two parameters indicating the position of the area as variables, and a signal related to the focus state obtained for each area and a signal related to the correction for each area are used for each area. The focus state is detected in each case.

According to an eleventh aspect of the present invention, as the focus detecting configuration of the ninth aspect, the focus state detecting means includes at least a pair of secondary imaging lenses and sensors corresponding to the secondary imaging lenses, respectively. The apparatus is configured to detect a focus state of the objective lens from a relative positional relationship between corresponding portions of two light amount distributions formed on a sensor.

According to a twelfth aspect of the present invention, as the focus state detecting means of the ninth aspect, rotational symmetry with respect to the optical axis of the objective lens or an optically equivalent axis to the optical axis of the objective lens is provided. It is configured in a device that does not have it.

According to a thirteenth aspect of the present invention, the parameter of the ninth aspect is a two-dimensional coordinate value with respect to a coordinate system defined on the predetermined focal plane or a plane equivalent thereto.

According to a fourteenth aspect of the present invention, in the ninth aspect, the predetermined arithmetic processing is an operation of a predetermined function using the parameter as a variable.

According to a fifteenth aspect of the present invention, in the ninth aspect, the objective lens is provided on an interchangeable lens mounted on the camera, and the focus detection apparatus is provided on the camera.

According to a sixteenth aspect of the present invention, the camera according to the fifteenth aspect is provided with a correction signal forming means, and the calculation of the correction value is performed in the camera.

According to a seventeenth aspect of the present invention, the correction signal forming means is provided in the interchangeable lens of the fifteenth aspect, and the calculation of the correction value is performed in the lens.

The invention according to claim 18 is the focus detection device according to claim 9, wherein the predetermined area on the predetermined focal plane of the objective lens is divided into a plurality of partial areas, and the two or more parameters are set in each partial area. Is set in accordance with the position of.

The invention described in claim 19 is the invention described in claim 18.
In the above configuration, the parameter is set to a plurality of values determined by the coordinate value of the center of the partial area.

[0041]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a conceptual diagram for explaining the operation of a photographing apparatus including a focus detecting device according to the present invention. In the figure, reference numeral 1 denotes a photographing lens as an objective lens, and inside thereof, a photographing optical system 2 and all the lenses constituting the photographing optical system 2,
Alternatively, it includes a driving unit 3 for adjusting a focus state of the photographing lens 1 by moving a part thereof, a storage unit 4 such as a ROM, and a lens control unit 5 for controlling them. On the other hand, a camera 6 includes a main mirror 7, a focusing screen 8, a pentaprism 9, and an eyepiece 10, which constitute a finder system. Further, it includes a sub-mirror 11, focus detection means 12, correction value calculation means 13, camera control means 14, and film 15 as a photographing medium. The taking lens 1 and the camera 6 have a contact point 16,
In a state where they are attached to each other, information communication and power supply are performed via the contact 16.

FIG. 2 is a diagram for explaining a detailed configuration of the focus detecting means 12. As shown in FIG. In the figure, reference numeral 17 denotes an optical axis of a photographic lens (not shown), reference numeral 18 denotes a film equivalent to reference numeral 15 in FIG.
1 is a semi-transmissive main mirror which is arranged on the optical axis 17 of the taking lens and is equivalent to 7 in FIG. 1, and 20 is similarly obliquely arranged on the optical axis 17 of the objective lens. A first reflecting mirror having a function, 21 is a paraxial image plane conjugated to the film 18 by the first reflecting mirror 20, 22 is a second reflecting mirror, 23 is an infrared cut filter, and 24 is two apertures. Aperture having 24-1 and 24-2, 25 is 2 of aperture 24
A secondary imaging system having two lenses 25-1 and 25-2 arranged corresponding to the two apertures 24-1 and 24-2, 36
Is a third reflecting mirror, 26 is two area sensors 26-1,
26 shows a photoelectric conversion element having 26-2.
Here, the first reflecting mirror 20 has a curvature,
The two apertures 24-1 and 24-2 have convergence power for projecting in the vicinity of the exit pupil of a photographic lens (not shown). Further, the first reflecting mirror 20 has a metal film such as aluminum or silver deposited so as to reflect light only in a necessary area, and also functions as a field mask for limiting a range in which focus detection is performed. In the other reflecting mirrors 22 and 36 as well, only the minimum necessary area is deposited to reduce stray light incident on the photoelectric conversion element. It is also effective to apply a light-absorbing paint or the like to a region that does not function as a reflecting surface of each reflecting mirror.

FIG. 3 is a plan view of the diaphragm 24, which is a horizontally long 2.
The two openings 24-1 and 24-2 are arranged in a direction in which the opening width is narrow. The dotted line in the figure indicates that each lens 25-of the secondary imaging system 25 disposed behind the apertures 24-1 and 24-2 of the diaphragm 24 in correspondence with the apertures 24-1 and 24-2.
1, 25-2.

FIG. 4 is a plan view of the photoelectric conversion element 26.
The two area sensors 26-1 and 26-2 shown in FIG. 2 are obtained by arranging two area sensors in which pixels are two-dimensionally arranged as shown in FIG.

In the above configuration, the light beams 27-1 and 27-2 from the photographing lens not shown in FIG. 2 pass through the main mirror 19, and then follow the inclination of the main mirror 19 by the first reflecting mirror 20. After being changed in direction again by the second reflecting mirror 22, each of the secondary imaging systems 25 passes through the infrared cut filter 23 and the two apertures 24-1 and 24-2 of the diaphragm 24. Focused by lenses 25-1 and 25-2,
The light reaches the area sensors 26-1 and 26-2 of the photoelectric conversion element 26 via the third reflecting mirror 36, respectively. The light fluxes 27-1 and 27-2 in the figure indicate the light flux that forms an image at the center of the film 18, but the light flux that forms an image at another position passes through the same path to the photoelectric conversion element 26. As a whole, two light quantity distributions corresponding to a predetermined two-dimensional area on the film 18 are formed on each of the area sensors 26-1 and 26-2 of the photoelectric conversion element 26. In the present embodiment, the first surface of the secondary imaging system 25 has a concave shape so that light incident on the secondary imaging system 25 is not forcibly refracted. Conversion element 26-2
Good and uniform imaging performance is secured over a wide range of the dimensional region. In addition, the first reflecting mirror 20 is used for photographing.
Like the main mirror 19, it is retracted outside the imaging optical path.

The focus detecting means 12 shown in FIG. 1 separates the two light quantity distributions obtained in this manner into separation directions, that is, two area sensors shown in FIG. 4 based on the same principle as that described with reference to FIG. The focus state of the photographing lens 1 is detected by calculating the vertical relative positional relationship between the area sensors 26-1 and 26-2 at the respective positions of the area sensors 26-1 and 26-2. Output as

According to the above focus detecting means, it is possible to detect the focus state at almost any point in the area of the film 18 corresponding to the area sensor 26, that is, in the focus detection area. Also, a focus detectable area 28 as shown in FIG.
It is also possible to enable focus detection only at a specific discrete position indicated by a rectangle inside. In this case, for example, a liquid crystal display element having a rectangular pattern shown in FIG. 5 is provided near the focusing screen 8 in FIG. Can be displayed.

When focus detection is performed discretely as shown in FIG. 5, a line sensor may be discretely provided for each focus detection area instead of the area sensor.

As described above, using the defocus amount D representing the focus state obtained from the relative positional relationship between the two images formed on the sensor as it is and controlling the photographing lens causes an error and accurate focusing can be performed. Therefore, it is necessary to correct the defocus amount D obtained at each position with a correction value corresponding to each position.

However, as is apparent from the configuration of the focus detection device, the focus detectable region 28 in FIG. 5 has only line symmetry with respect to the vertical line 30 passing through the center 29 thereof, and has line symmetry with respect to the horizontal line 31. And there is no rotational symmetry with respect to a straight line passing through the center 29 and perpendicular to the page. Therefore, the characteristic of each point in the focus detectable area 28 is the center point 2
The distance cannot be defined only by the distance from the center 9, and the correction value cannot be expressed by a value relating only to the distance from the center.

For this reason, in FIG.
Numeral 3 calculates a correction value C using two or more parameters corresponding to an area where focus detection is to be performed. For example, assuming that the area for which focus detection is to be performed is 32 in FIG. 5, correction is performed by the following equation using the coordinates x and y of the center 33 of this area whose origin is the center 29 of the focus detectable area as a parameter. The value C is determined.

[0052]

[Outside 1]

Here, i and j are continuous or discontinuous integers in a predetermined range. a _ij is determined by i and j,
One or a plurality of constants, which are stored in the storage means 4 in the taking lens 1 and which are transmitted from the lens control means 5 to the camera control means 14
Handed over to Note that the coordinates x and y need not necessarily be coordinates on the predetermined focal plane or film plane, but may be coordinates on a plane equivalent to these. The unit of the coordinate value may be standardized so as to be optimal for the calculation of the expression (2).

The camera control means 14 calculates the defocus amount D obtained by the focus detection means 12 and the correction value calculation means 13
Using the correction value C obtained from equation (2),
Performs calculation similar to the expression to calculate the corrected focus detection signal D _C. Correcting the focus detection signal D _C as it is, or after being converted to the lens drive amount, and the like if necessary, and sent to the lens control unit 5 via the contact 16. The lens control means 5 controls the driving device 3 based on the received signal to move all or a part of the lens constituting the photographing optical system 2 and adjust the focus state of the photographing lens 1.

FIG. 6 is a bird's-eye view showing the correction value C of a certain photographing lens, and the correction value for the focus detectable area 34 is shown by a continuous curved surface 35. Curved surface 3 shown in this figure
5 is expressed in the form of equation (2), and specific values of the coefficients a _ij are as follows.

A ₀₀ = 1.53023 × 10 ⁻¹ a ₀₁ =
2.25555 × 10 ⁻³ a ₀₂ = −3.446357 × 1
_{^{0 -3 a 20 = -5.83510 × 10}} -4 a 21 = -5.500
92 × 10 ⁻⁵ a ₂₂ = 3.89544 × 10 ⁻⁶

In this example, the correction value C is a quadratic expression relating to x and y.
_1j (j = 0, 1, 2) are all 0, and the values of the correction values C at all positions in the focus detectable area are represented by six coefficients.

In the above example, i = 0, 2 j = 0, 1, 2, but the range of i and j is not limited to this.

When the focus detection area is divided into predetermined partial areas as shown in FIG. 5, the x ⁱ y ^j portion of the equation (2) for each area x and y is determined in advance. Calculate and use x ⁱ y ^j instead of x and y as parameters
Is stored in the storage means on the camera side and is read out at the time of calculation of the expression (2), whereby the calculation time can be greatly reduced.

In this example, the equation (2) is assumed as an arithmetic equation for obtaining the correction value C. However, the present invention is not limited to this, and other equations such as a logarithmic function and a trigonometric function are used. It is also possible to use a function represented by a function or a combination thereof. Also, 1 for all focus detection areas
If the error becomes large when expressing the correction value with two functions,
The focus detection area may be divided into several parts, and the correction value of each area may be represented by a spline function that is continuously connected.

Further, different focus detection means correspond to each focus detection area, and when the correction value does not continuously change over the entire focus detection area, a different function is defined for each area, It is also possible to calculate a correction value using a coefficient suitable for each area.

On the other hand, when the present invention is applied to a system in which many types of lenses are exchanged and used, such as a single-lens reflex camera, it is not possible to limit the arithmetic expression for obtaining the correction value C to one. In this case, a plurality of types of functions may be prepared in advance, and information specifying the type of the function to be used and the method of the operation procedure may be read from the lens together with the coefficient required for calculating the correction value C.

FIG. 7 is a diagram showing another embodiment of the present invention, in which the same components as those in FIG. 1 are denoted by the same reference numerals. This example is different from the first example in that the correction value calculation means 13 on the camera side in FIG.
Is on the lens side. The calculation of the correction value and the correction of the focus detection signal according to this embodiment are performed as follows. First, the lens control unit 5 sets the coordinates x and y representing the position of the focus detection area where the focus detection is to be performed on the camera control unit 1 in the camera.
4 via the contact 16. Subsequently, the lens-side correction value calculation means 13 ′ calculates the correction C by using the value and the coefficient data a _ij in the storage device 4 to obtain the correction C, and the result is transmitted to the lens control means 5 and the contact point 16. It is sent to the camera control means 14 on the camera side via the camera. After that, correction of the focus detection signal and driving of the photographing lens are performed as in the first example.

In the case of this example, since the correction value is calculated on the lens side, the form of the arithmetic expression of the correction calculation can be freely set according to each lens. There is an advantage that optimal correction can be performed for the lens.

[0065]

According to the first aspect of the present invention, according to the output and the correction value in a predetermined area in a sensor section having a light receiving area arranged on a two-dimensional axis for receiving a light beam passing through an objective lens, In the focus detection device that detects the focus state by using the two parameters indicating the position of the predetermined area of the sensor unit as a calculation variable, the correction value for the predetermined area is calculated. Using the coordinate value of the center of each area with respect to the origin of the expected focal plane that spreads out, a predetermined function value was calculated and the correction value in each area was obtained, so that it was not necessary to store all the correction values for each area. A correction value can be obtained.

According to a second aspect of the present invention, in the configuration for obtaining the correction value according to the first aspect, the correction values in a plurality of regions of the sensor unit are each used as a parameter indicating the position of each region as a calculation variable. Since this is obtained, the same effect as that of claim 1 can be obtained.

According to a third aspect of the present invention, as the configuration for obtaining the correction value in the first aspect, data representing coordinates relating to the position of each area in the sensor section is used as the parameter. One device can be simply configured.

According to a fourth aspect of the present invention, in the configuration for obtaining the correction value according to the first aspect, a region in the sensor section for receiving a light beam from an optical axis of an objective lens is set as a center coordinate and coordinates of other regions are set. Since a value is used as the parameter, an effect similar to that of the third aspect is obtained.

According to a fifth aspect of the present invention, the correction value is calculated by a function using predetermined data as a coefficient and the parameter as a variable. Therefore, the correction value can be easily obtained.

According to a sixth aspect of the present invention, as a configuration for obtaining the correction value of the first aspect, data for calculating the correction value is stored in a lens device mounted on a camera, and the correction value is stored in the lens device. The stored data is communicated to the camera, and the correction value is calculated in the camera using the data and the parameters, so that appropriate processing can be performed regardless of the attached lens.

According to a seventh aspect of the present invention, predetermined coefficient data is provided as the data of the sixth aspect, and the correction value is calculated by a function using the data as a coefficient and the parameter as a variable. Therefore, an effect similar to that of the fifth aspect is obtained.

According to an eighth aspect of the present invention, as the focus detection structure of the first aspect, a signal relating to a focus state is obtained by an output in each area of the sensor unit, and the signal is corrected by a correction value in that area. Since the focus state is detected in the area, the appropriate focus detection can be realized without storing the correction value for each area as in the first aspect.

According to a ninth aspect of the present invention, there is provided a focus state detecting means for obtaining a signal relating to the focus state of the objective lens for a predetermined area on the predetermined focal plane of the objective lens, and By a predetermined arithmetic processing including two or more parameters set corresponding to the position of the region,
Correction signal forming means for obtaining a signal related to correction for the area, and detecting a focus state in the area based on the signal related to the focus state and the signal related to correction,
It is an object of the present invention to provide a focus detection device which can obtain a correction value in each area without storing a correction value for each area.

According to a tenth aspect of the present invention, in the ninth aspect, each of the focus detecting devices includes a sensor unit having a plurality of light receiving regions arranged on a two-dimensional axis for receiving a light beam passing through an objective lens. A signal related to the correction for each area is obtained by an operation using two parameters indicating the position of the area as variables, and a signal related to the focus state obtained for each area and a signal related to the correction for each area are used for each area. Therefore, the same effects as those of the first aspect can be obtained.

According to an eleventh aspect of the present invention, as the focus detecting configuration of the ninth aspect, the focus state detecting means includes at least a pair of secondary imaging lenses and sensors corresponding to the respective secondary imaging lenses. 2. A passive autofocus having the effect of claim 1, wherein the apparatus is configured to detect a focus state of the objective lens from a relative positional relationship between corresponding portions of two light quantity distributions formed on a sensor. realizable.

According to a twelfth aspect of the present invention, as the focus state detecting means of the ninth aspect, rotational symmetry with respect to the optical axis of the objective lens or an optically equivalent axis to the optical axis of the objective lens is provided. Since it is configured in a device that does not have such a configuration, a correction value can be obtained effectively.

According to a thirteenth aspect of the present invention, the parameter of the ninth aspect is a two-dimensional coordinate value with respect to a coordinate system defined on the predetermined focal plane or a plane equivalent thereto. 9 can be easily realized.

According to a fourteenth aspect of the present invention, since the predetermined arithmetic processing according to the ninth aspect is an operation of a predetermined function using the parameter as a variable, the operation of the ninth aspect can be easily performed. it can.

According to a fifteenth aspect of the present invention, as the focus detecting device of the ninth aspect, the objective lens is provided on an interchangeable lens mounted on the camera, and the focus detecting device is provided on the camera. A focus detection device having a configuration suitable for a camera system of an interchangeable lens can be provided.

According to a sixteenth aspect of the present invention, a correction signal forming means is provided in the camera of the fifteenth aspect, and the calculation of the correction value is performed in the camera. Therefore, an apparatus suitable for an interchangeable lens system can be provided. it can.

According to a seventeenth aspect of the present invention, the correction signal forming means is provided in the interchangeable lens of the fifteenth aspect, and the calculation of the correction value is performed in the lens. Therefore, an apparatus suitable for an interchangeable lens system can be provided. it can.

The invention according to claim 18 is the focus detection device according to claim 9, wherein the predetermined area on the expected focal plane of the objective lens is divided into a plurality of partial areas, and the two or more parameters are set in each partial area. The apparatus according to claim 9 can be easily realized because the apparatus is configured to be set in accordance with the position.

The invention described in claim 19 is the invention described in claim 18.
In the above configuration, the parameter is set to a plurality of values determined by the coordinate value of the center of the partial area, so that the apparatus according to claim 9 can be easily realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a first embodiment of a camera system employing a focus detection device according to the present invention.

FIG. 2 is a diagram illustrating an optical configuration of a focus detection unit to which the first embodiment of the present invention is applied.

FIG. 3 is a diagram illustrating an aperture of a focus detection unit to which the first embodiment of the present invention is applied;

FIG. 4 is a diagram illustrating a photoelectric conversion element of a focus detection unit to which the first embodiment of the present invention is applied.

FIG. 5 is a diagram illustrating a focus detection area of a focus detection unit to which the first embodiment of the present invention is applied.

FIG. 6 is a diagram illustrating correction values according to the first embodiment of the present invention.

FIG. 7 is a diagram illustrating a configuration of a second exemplary embodiment of the present invention.

FIG. 8 is a diagram showing a conventional example of a camera having a focus detection device.

FIG. 9 is a diagram showing a first conventional example of a focus detection device.

FIG. 10 is a diagram showing a second conventional example of a focus detection device.

FIG. 11 is a diagram showing a photoelectric conversion element in a second conventional example of a focus detection device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photographing lens 2 photographing optical system 3 driving device 4 storage device 5 lens control means 6 camera 7 main mirror 8 focusing plate 9 pentaprism 10 eyepiece lens 11 sub mirror 12 focus detection means 13, 13 'correction calculation means 14 camera control means 15 film DESCRIPTION OF SYMBOLS 16 Contact 17 Optical axis of photographing lens 18 Film 19 Primary mirror 20 First reflecting mirror 21 Image plane 22 Second reflecting mirror 23 Infrared cut film 24 Aperture 25 Secondary imaging system 26 Photoelectric conversion element 27 From photographing lens 28 Focus detectable area 29 Center of focus detectable area 30 Vertical line passing through center 31 Horizontal line passing through center 32 Focus detect area 33 Center of focus detect area 34 Focus detectable area 35 Curved surface indicating correction value 36 Third Reflecting mirror 101 Objective lens 102 Main mirror 103 Focusing plate 104 Pentagram Rhythm 105 Eyepiece 106 Submirror 107 Film 108 Focus detection device 109 Field mask 110 Field lens 111 Secondary imaging system 112 Photoelectric conversion element 113 Aperture 114 Objective lens exit pupil 115 Light flux 116 Field mask 117 Field lens 118 Aperture 119 Optical member 120 Photoelectric conversion element 121 Image on photoelectric conversion element

Claims (19)

[Claims] 1. A light receiving device that receives a light beam that has passed through an objective lens.
In a focus detection device that detects a focus state according to an output and a correction value in a predetermined region in a sensor unit having a light receiving region disposed on a dimensional axis, two parameters indicating a position of the predetermined region of the sensor unit Wherein a correction value for the predetermined area is calculated by using a calculation variable as a calculation variable. 2. The focus detection apparatus according to claim 1, wherein correction values in a plurality of regions of the sensor unit are respectively obtained as parameters indicating the position of each region as a calculation variable. 3. The focus detection device according to claim 1, wherein data representing coordinates relating to the position of each area in the sensor unit is used as the parameter. 4. The apparatus according to claim 1, wherein an area of the sensor section for receiving a light beam from an optical axis of an objective lens is used as central coordinates, and coordinate values of other areas are used as the parameters. Focus detection device. 5. The focus detection apparatus according to claim 1, wherein the correction value is calculated by a function using predetermined data as a coefficient and using the parameter as a variable. . 6. The data for calculating the correction value is stored in a lens device attached to the camera, the data stored in the lens device is communicated to the camera, and the data and the parameters are used. The focus detection device according to claim 1, wherein the correction value is calculated in the camera. 7. The focus according to claim 6, wherein the data is predetermined coefficient data, and the correction value is calculated by a function using the data as a coefficient and using the parameter as a variable. Detection device. 8. The method according to claim 1, wherein a signal related to a focus state is obtained from an output of each area of the sensor unit, and a focus state in the area is detected by a correction value in the area. Or the focus detection device according to 2 or 3 or 4 or 5 or 6 or 7. 9. A focus state detecting means for obtaining a signal relating to a focus state of the objective lens for a predetermined area on a predetermined focal plane of the objective lens, and a focus state detecting means corresponding to a position of the predetermined area on the predetermined focal plane. Correction signal forming means for obtaining a signal related to correction for the area by a predetermined arithmetic processing including two or more set parameters; and detecting a focus state in the area based on the signal related to the focus state and the signal related to correction. A focus detection device characterized by the above-mentioned. 10. A method according to claim 1, wherein each of the plurality of light receiving regions receives a light beam passing through the objective lens and has a plurality of light receiving regions arranged on a two-dimensional axis. 10. The focus detection device according to claim 9, wherein a signal relating to correction for the respective regions is obtained, and a focus state is detected for each of the regions based on the signal relating to the focus state obtained for each of the regions and the signal relating to correction for each of the regions. 11. The apparatus according to claim 11, wherein said focus state detecting means is at least two.
Detecting a focus state of the objective lens from a relative positional relationship between corresponding portions of two light amount distributions formed on the sensor, each including a set of secondary imaging lenses and a corresponding sensor. The focus detection device according to claim 9, wherein: 12. The apparatus according to claim 1, wherein the focus state detecting means has no rotational symmetry with respect to an optical axis of the objective lens or an axis optically equivalent to the optical axis of the objective lens.
2. The focus detection device according to 1. 13. The apparatus according to claim 9, wherein the parameter is a two-dimensional coordinate value with respect to a coordinate system defined on the predetermined focal plane or a plane equivalent thereto.
Or the focus detection device according to 12. 14. The focus detection device according to claim 9, wherein the predetermined calculation process is a calculation of a predetermined function using the parameter as a variable. 15. The camera according to claim 9, wherein the objective lens is provided on an interchangeable lens mounted on the camera, and the focus detection device is provided on the camera.
15. The focus detection device according to 1 or 12 or 13 or 14. 16. The focus detecting device according to claim 15, wherein said correction signal forming means is provided in a camera. 17. The focus detecting device according to claim 15, wherein said correction signal forming means is provided in an interchangeable lens. 18. The method according to claim 18, wherein the predetermined area on the predetermined focal plane of the objective lens is divided into a plurality of partial areas, and the two or more parameters are set corresponding to the position of each partial area. The focus detection device according to claim 9, 11, 12, or 13. 19. The focus detection device according to claim 18, wherein the parameter is a plurality of values determined by a coordinate value of a center of the partial area.