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公开(公告)号：JPH01241510A
公开(公告)日：1989-09-26
申请号：JP6808888
申请日：1988-03-24
Applicant: CANON KK
Inventor： OTAKA KEIJI , KOYAMA TAKASHI
Abstract: PURPOSE:To eliminate the influence of ghost light and to improve focus detecting accuracy by making ghost output value correspond to the arranged state of an object lens and storing the ghost output value beforehand. CONSTITUTION:A lens side storing means 14 stores and holds beforehand a functional type or discrete functional value with respect to the value of a focusing lens position and a zooming position segmented into plurals. On the other hand, the ghost light amount per unit light emission amount of a light emitting means 2 generated by reflection at an optical system 8 in a camera main body device 1 is thought to be fixed as long as there are not any movable parts. A camera side storing means 6 stores and holds beforehand the ghost output value of two photodetectors of a light receiving means 3 by the ghost light. Therefore, a detected focus point is obtained based on the corrected output value of the light receiving means 3 eliminating the influence of the ghost light. Thus, accuracy can be improved.
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公开(公告)号：JPS63298003A
公开(公告)日：1988-12-05
申请号：JP13370487
申请日：1987-05-29
Applicant: CANON KK
Inventor： KOYAMA TAKASHI , NODAGASHIRA HIDEFUMI
Abstract: PURPOSE:To detect even a fine pattern which can not be detected conventionally by arranging the opening of a mask nearly at the intermediate position between a light projecting element and light receiving element, and designing the width (x) of the opening of the mask so that a specific expression holds. CONSTITUTION:In a figure, there are a margin (gap) between a segment R2 and a mask opening edge 4'' and a margin (gap) between a segment R1 and a mask opening edge 4', so luminous flux regarding a low reflection part is incident on the light receiving element 2 to lower the S/N slightly. For the improvement of the S/N, the inequality I holds preferably. When the distance lbetween the mask 4 and a pattern 3 is extremely small, on the other hand, a 1st term in the right member of the expression I is a small value, so as value (x) approximates (a) and when the opening width (x) of the mask 4 becomes smaller than (a), the pattern can not be detected, so that (a) should be larger then (x). For the purpose, the mask 4 is so designed that a
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公开(公告)号：JPS6398613A
公开(公告)日：1988-04-30
申请号：JP24469186
申请日：1986-10-15
Applicant: CANON KK
Inventor： KOYAMA TAKASHI , OTAKA KEIJI
Abstract: PURPOSE:To vary a focusing visual field range optionally and to perform high-accuracy focus detection by varying the focusing visual field range by a driving means which moves a visual field mask and a prism member in the mutually opposite directions in parallel to the array direction of a light receiving element array. CONSTITUTION:Opening parts 7-1 and 7-2 of the mask 7 are image-formed at the pupil of an objective 1 by a field lens 3 and the pupil of the objective 1 is divided optically into two areas 1a and 1b. The 2nd two object images are formed on the surface of the photodetecting element array 9 and the relative position relation between the two object images is found to detect the focusing state of the objective 1. The driving means 15 moves the visual field mask 14 and prism member 13 in the mutually opposite directions in parallel to the array direction of the light receiving element array 9 as shown by arrows 16 and 17 to prevent pieces of luminous flux regarding the two object images formed on the surface of the light receiving element array 9 from overlapping with each other on an optical path, and thus the focusing visual field range is varied while the optical performance of the object images is maintained excellently. Consequently, even if the focusing visual field range is varied, the excellent focus detection accuracy is obtained all the time.
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公开(公告)号：JPS6388536A
公开(公告)日：1988-04-19
申请号：JP23133386
申请日：1986-10-01
Applicant: CANON KK
Inventor： SUDA YASUO , ARAKAWA KAZUHIKO , OTAKA KEIJI , KOYAMA TAKASHI , ONUKI ICHIRO
IPC: G02B7/34 , G03B3/00 , G03B7/099 , G03B7/0997 , G03B13/36
Abstract: PURPOSE:To optimize a spectral sensitivity distribution by dividing a filter into a 1st area including its transmitted part and a 2nd area of other parts, and determining the spectral transmissivity of the 1st area and the spectral transmissivity of the 2nd area suitable to a sensor for focus detection and a sensor for photometry respectively. CONSTITUTION:An infrared-ray cutting filter 21 consists of two areas 21a and 21b which differ in spectral transmissivity characteristics; and the infrared-ray cut wavelength of the area 21a is 700nm and the infrared-ray cut wavelength of the area 21b is 740nm. The effective parts of a dimming system and an AE system cover the two areas and the rate of the area 21a of either system is smaller than that of the area 21b, so light is measured photometrically with characteristics close to spectral sensitivity characteristics (400-700nm) of a film. On the other hand, the effective part of the AF system is constituted while included completely in the area 21a and an irregularity in illuminance on a line sensor surface is eliminated. Consequently, the sensor for focus detection and sensor for photometry are given different spectral transmissivity characteristics and the spectral sensitivity distributions of the sensors are optimized.
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公开(公告)号：JPS6388512A
公开(公告)日：1988-04-19
申请号：JP23132986
申请日：1986-10-01
Applicant: CANON KK
Inventor： SUDA YASUO , ARAKAWA KAZUHIKO , OTAKA KEIJI , KOYAMA TAKASHI , ONUKI ICHIRO
Abstract: PURPOSE:To prevent erroneous detection of focusing by providing a 1st adjusting mechanism for one of sensor holding members in the direction where a pair of sensors for focus detection are arrayed and a 2nd adjusting mechanism for the other sensor holding member. CONSTITUTION:A sensor block 24 and a sensor holder 25 are disposed below a secondary imaging lens 12. These parts together with a screw 27, a washer 28 and an eccentric pin 29 constitute the inclination adjusting mechanism for the sensor holding member 13 for AF.AE disposed in the lower part thereof. The inclination and adjustment of the sensor block 24 in an arrow D direction are possible, because the hole mounting said block is a long hole. The sensor holder 25 is fixed to the block 24 by an eccentric pin 29 as well via the mounting hole 24b which is a long hole. Since the curved part 25b of the holder 25 is substantially reduced in the thickness so as to have flexibility, the sensor holder can be inclined and adjusted approximately around the axis E in an arrow F direction. The error in the distance measurement is thereby corrected.
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Patent Agency Ranking
公开(公告)号：JPS6318312A
公开(公告)日：1988-01-26
申请号：JP16082386
申请日：1986-07-10
Applicant: CANON KK
Inventor： AKASHI AKIRA , ISHIZAKI AKIRA , SUDA YASUO , ONUKI ICHIRO , OTAKA KEIJI , KOYAMA TAKASHI
Abstract: PURPOSE:To detect a focus state with higher accuracy by comparing contrast evaluated quantities over the whole range of relative displacement and using a larger focus evaluated quantity for the calculation of an image shift quantity. CONSTITUTION:The 1st and the 2nd signals from photoelectric converting means SAA and SAB are displaced relatively in order through arithmetic operation and the integral value of larger signals between the 1st and the 2nd signals which correspond at each relative displacement position is used as the 1st evaluated quantity while the smaller integral value is used as the 2nd evaluated quantity. Then the 1st and the 2nd evaluated quantities are computed by relative interval to find the shift quantity between the 1st and the 2nd images on the basis of the 1st evaluated quantity or the 2nd evaluated quantity, thereby detecting the focus state of an image formation optical system FLNS. Then, the contrast evaluated quantities depending upon the contrast of the 1st and the 2nd signals is found from the 1st and the 2nd evaluated quantities to select the 1st or 2nd respective evaluated quantities used to finds the shift quantity between the 1st and the 2nd images according to the large/small relation between the contrast evaluated quantities.
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公开(公告)号：JPS62215214A
公开(公告)日：1987-09-21
申请号：JP5853986
申请日：1986-03-17
Applicant: CANON KK
Inventor： KOYAMA TAKASHI , OTAKA KEIJI
Abstract: PURPOSE:To expand the arrival distance of a pattern and to enable high-accuracy detection while expanding a distance measurement range by arranging an optical member which has converging power only in the lengthwise direction of a light emit ting tube in front of an bar chart and projecting the image of the aperture on a subject side. CONSTITUTION:The bar chart 2 is arranged in front of the light emitting tube 3 and the pattern of the lighted bar chart 2 is projected on the subject through an optical member 1 with specific refracting power. At this time, the reflecting surface of a reflecting mirror 4 is composed of an elliptic surface or parabolic surface having its focus on the center axis of the light emitting tube 3 and luminous flux from the light emitting tube 3 is irradiated efficiently. The optical member 1 is so constituted as to have converging force in the same direction as that of the pattern that the bar chart 2 has because the bar chart 2 has the pattern only in the direction, and the pattern is projected on the subject side efficiently. The light emitting tube 3 is so controlled by a control means as to emit light manually or when a photodetecting means provided to part of the camera judges that the environment is darker than a specific value or when an automatic focus detecting means judges that the contrast of the subject is lower than a specific value.
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公开(公告)号：JPS62161110A
公开(公告)日：1987-07-17
申请号：JP300386
申请日：1986-01-10
Applicant: CANON KK
Inventor： ONUKI ICHIRO , SUDA YASUO , ISHIZAKI AKIRA , AKASHI AKIRA , OTAKA KEIJI , KOYAMA TAKASHI
Abstract: PURPOSE:To eliminate the error of distance measurement arising from the inclination of a line sensor for photodetection of a luminous flux and the eccentricity of a secondary imaging lens by interposing adjusting members which contact each other at the contact surfaces inclined with the optical axis between the line sensor and sensor holding member for holding the sensor. CONSTITUTION:All the optical members from a sub-mirror 12 up to the line sensor 6 are concentrically mounted to one unit body 14. An IR cut filter 15 and a reflection preventive member 16 are inserted between the mirror 12 and a field mask 2. The member 16 is used to prevent the arrival of the reflected light from the surface of the filter 15 at a film 11. The adjusting members consisting of a stationary member and rotating member which contact each other at the contact surfaces inclined with the optical axis, i.e., a stationary stage 17 and a rotating stage 18 are interposed between the line sensor 6 and the unit body 14 holding the same. The inclination of the line sensor 6 is adjusted by rotating the stage 18.
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公开(公告)号：JPS62138808A
公开(公告)日：1987-06-22
申请号：JP28059185
申请日：1985-12-12
Applicant: CANON KK
Inventor： SUDA YASUO , ONUKI ICHIRO , AKASHI AKIRA , ISHIZAKI AKIRA , OTAKA KEIJI , KOYAMA TAKASHI
Abstract: PURPOSE:To put, for example, a sweater of lateral stripe pattern and a window blind which can not be detected by a conventional passive type focus detecting device in focus by performing focus detection based on object brightness distributions in plural directions. CONSTITUTION:A visual field mask 103 is arranged nearby the primary image forming surface of a photographic lens 106 and a field lens 102 is so arranged as to project an image of a multi-aperture stop 103 on the exit pupil of the photographic lens, so visual field mask images 109a-109d are formed with pieces of luminous flux passed through four mutually separated areas 108a-108d of the exit pupil 107. Namely, phase difference detection type focus detection optical systems are constituted for the respective pieces of luminous flux passed through the areas 108a and 108c, and 108b and 108d on the exit pupil. Therefore, the image illuminance distribution in a visual field mask image 109 shifts inward from the position in an in-focus state as shown by an arrow in an out-of-focus state.
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公开(公告)号：JPS62133410A
公开(公告)日：1987-06-16
申请号：JP27256485
申请日：1985-12-05
Applicant: CANON KK
Inventor： AKASHI AKIRA , ISHIZAKI AKIRA , SUDA YASUO , ONUKI ICHIRO , OTAKA KEIJI , KOYAMA TAKASHI
Abstract: PURPOSE:To execute precisely focus detection even if any image forming optical system is loaded by changing an arithmetic range in which the 1st and 2nd signals are relatively changed based on of the positional information of the image forming optical system in its optical axis direction and making the arithmetic range include all the movable range of the image forming optical system in its optical axis direction. CONSTITUTION:The maximum defocusing variable MD of a lens loaded at present is obtained from a ROM in an intra-lens control circuit LPRS and the size of the arithmetic range of a relative displacement value (k) is set up in accordance with the information. Namely, the range of the relative displacement value (k) is increased at the loading of a lens such as a telephoto lens having a large maximum defocusing value MD, and at the loading of a lens such as a wide angle lens having a small maximum defocusing value, the range of the (k) is reduced. The positional information DV of a photographing lens LNF at the start of focus detection is obtained and the relative displacement value (k) is displaced in an effective direction to determine the arithmetic range. Consequently, the arithmetic range coincides with the movable range of the lens LNF and focus detection can be precisely attained even if any focus adjusting lens is loaded.
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