JPH06332040A - Camera equipped with finder light quantity control means - Google Patents

Abstract

PURPOSE:To prevent adverse influence on a pupil even if a photographer views the object of high luminance (the sun, etc.) through a finder. CONSTITUTION:A camera switch 31 is turned on, and a photometric value obtained by the actuation of a photometry means 32 is compared with a reference photometric value 34 by a photometric value comparing means 33 and inputted to an OR circuit 37 together with zoom information 35a. The OR circuit 37 executes output only when the camera is turned towards the object of the high luminance in the tele-state of a zoom and when a first analog switch 39 is turned on and a second analog switch 40 is turned on, a diaphragm means 43a in a photographic lens system is actuated and the control of the decrease of the quantity of light entering the pupil of the photographer is executed. Moreover, a finder light quantity control means operation display 44 informs the photographer that the diaphragm means 43a is actuated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera having a finder light amount control means for entering a pupil of a subject having high brightness.

[0002]

2. Description of the Related Art In a conventional camera, when a photographer views a high-brightness subject (sun or the like) with a finder, the eyes may be adversely affected, but there is no measure for protecting the eyes. However, recent lenses have become higher in magnification, and when the sun is viewed through the viewfinder of a camera equipped with a high-magnification lens, in the worst case, there is a possibility that the pupils may be burned and blindness may occur. Moreover, recent cameras have many functions, and one of them is a camera that can be switched to a telescope.

A camera capable of switching to this type of telescope will be described below with reference to FIG. That is, the taking lens 1 supported by the lens barrel 2 serves as a finder optical path system.
The light that has passed through is bent backward through the quick return 3, which performs an operation of retracting from the photographing optical path at the time of photographing, the condenser lenses 4, 5 and the reflection mirror 6, and further, through the reflection mirror 7, the switching lens 11 and the reflection mirror 8. Then, the lens is bent backward again so that it can be observed through the convex lens 9 and the eyepiece lens 10, and the condenser lenses 4 and 5, the switching lens 11, the convex lens 9 and the eyepiece lens 10 constitute a finder optical system. The switching lens 11 is held by the lens holder 12 fixed to the switching lever 13, and the switching lever 13 is connected to the switching connecting plate 15.
Is fixed to the switching gear 14 that meshes with the gear portion of the switching gear 14, and a toggle spring 16 is provided between the switching gear 14 and the switching connecting plate 15.
Are hung on each other. Further, a changeover switch 17 that is turned on / off by the rotation of the changeover connecting plate 15 is provided, and the rotation of the changeover lens 11 causes the changeover lens 11 to rotate 90 degrees, so that it is positioned in front of the reflection mirror 7 from the normal viewfinder state shown in the figure. The position of the finder optical path is changed so that the magnification is increased, and the state of the telescope optical system is obtained.

[0004]

By the way, in a camera capable of switching between normal and telescopes as in the above-mentioned conventional example, when the sun is mistakenly viewed by setting it in the telescope, the sunlight is focused on the pupil to ensure The problem of burning my eyes has arisen.

In view of the above-mentioned problems of the conventional example, it is an object of the present invention to provide a camera having a viewfinder capable of protecting the pupil even when strong light enters the viewfinder optical system during viewfinder observation.

[0006]

In order to achieve the above-mentioned object, the camera of the present invention controls the viewfinder light amount so that the light amount incident on the photographer's pupil is reduced or not incident as the subject brightness increases. It is equipped with means.

[0007]

In the camera having the above structure, when strong light enters the finder, the finder light amount control means reduces the light, so that the pupil of the photographer can be protected.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic sectional view of a camera of this embodiment, and FIG. 2 is a block circuit diagram showing a configuration for its operation. In FIG. 1, 21 is a taking lens system, 22 is a viewfinder eyepiece, 23 is an aperture arranged in the taking lens system 21, 24 is a quick return mirror provided at the rear of the taking lens system 21, and 25 is a quick return mirror 24.
Of the pentaprism 26, 26 is an eyepiece shutter or eyepiece diaphragm provided at the front of the viewfinder eyepiece 22, 27 is a photometric sensor provided at the rear of the pentaprism 25, and F is a film arranged at the focal plane. is there.
Then, the photographing light incident from the photographing lens system 21 is guided to the pentaprism 25 by the quick return mirror 24, one of which passes through the viewfinder eyepiece portion 22 so that the photographer can observe it, and the other enters the photometric sensor 27. , Get exposure data.

In FIG. 2, reference numeral 31 is a camera main switch, and 32 is a photometric means, which corresponds to the photometric sensor 27 of FIG. Reference numeral 33 is a photometric value comparing means, to which a signal from the photometric means 32 and a signal of a reference photometric value 34 described later are input. 34
Is a reference photometric value, 35a is zoom information, and 36 is an interval timer, which is connected to the camera main switch 31 and outputs the output signal to the photometric means 32. 37 is OR
The output signal from the photometric value comparing means 33 and the output signal from the zoom information 35a are input to the circuit. 38 is a timer to which the output signal of the OR circuit 37 is input. A first analog switch 39 receives the output signal of the OR circuit 37 and the signal from the timer 38. A second analog switch 40 is connected to the first analog switch 39.

Reference numeral 41 denotes a forced non-operating means, which is connected to the camera main switch 31 and the output signal of which is input to the second analog switch 40. Reference numeral 42 denotes a forced non-operation means operation display, to which the output signal of the forced non-operation means 41 is input. 43a is a diaphragm means, which corresponds to the diaphragm 23 in FIG.
It is connected to the output side of the second analog switch 40.
Reference numeral 44 is a viewfinder light amount control means operation display, to which a signal from the diaphragm means 43a is input.

With regard to the operation of the present embodiment having the above-mentioned configuration, when the camera main switch 31 is turned on, the interval timer 36 operates the photometric means 32 at a constant interval, and the obtained photometric value is measured by the photometric value comparing means 33 as the reference photometric value. Value 34
And is output to the OR circuit 37.

Further, the OR circuit 37 has zoom information 35a.
Is input, and the OR circuit 37 outputs only when the zoom is in the tele state and the camera is aimed at a high-brightness subject such as the sun, and the first analog switch 39 is turned on. The second analog switch 40 is normally turned on, and when the first analog switch 39 is turned on, the diaphragm means 43a operates to control the amount of light entering the pupil of the photographer to protect the pupil. Further, the finder light quantity control means operation display 44 informs the photographer that the diaphragm means 43a has been activated.
The light amount control of the diaphragm means 43a is released by turning off the first analog switch 39 for a fixed time by the timer 38.

The light quantity control can be forcibly deactivated by turning off the second analog switch 40 by the forced deactivation means 41. At this time, the operation display 42 of the forced non-actuating means informs the photographer that the light amount control is in the non-actuated state by displaying it in the finder or the like. In the above description, the light amount control is performed only when the zoom information 35 is tele, but the light amount control may always be performed at any focal length. In this embodiment, the diaphragm 23 controls the light amount during finder observation.
It is also possible to control the light amount by using 6.

FIG. 3 shows a second embodiment of the present invention. For simplification of description, the same parts as those in the first embodiment are designated by the same reference numerals, and only different points will be described. This embodiment is applied to a lens shutter camera.
, 61 is a taking lens, 62 is a viewfinder eyepiece, 63 is a lens shutter arranged on the taking lens 61,
Reference numeral 64 is a finder optical system, 65 is an eyepiece shutter or an eyepiece diaphragm provided in the finder optical path, 6
6 is a photometric sensor. The block circuit for the operation is the diaphragm means 4 in the first embodiment.
3a is the same except that it operates to control the light amount by the eyepiece shutter or the eyepiece diaphragm 65.

4 and 5 show a third embodiment of the present invention. For simplification of description, the same parts as those in the first embodiment are designated by the same reference numerals, and only different points will be described. In this embodiment, the finder system is applied to a camera capable of switching a telescope. In the schematic configuration diagram of the camera of FIG. 3, reference numeral 71 is a taking lens, 72 is a viewfinder eyepiece, 73 is a shutter also used as an aperture on the taking lens 71, 74 and 75 are reflection mirrors for the viewfinder optical path system, and 76 is a viewfinder. A system lens, 77 is an eyepiece shutter or an eyepiece diaphragm, and 78 is a half mirror for allowing a part of the finder light to enter the photometric sensor 79. As for the block circuit for the operation of FIG. 5, the zoom information in the first embodiment is 35.
It is the same as the first embodiment except that a is the telescope mode information 35b and the diaphragm means 43a is the shutter means 43b composed of the diaphragm shutter 73.

In this embodiment having the above construction, the input to the OR circuit 37 is the photometric value comparing means 33 and the telescope mode information 35b.
The analog switch 39 is turned on only when the high-brightness subject is set to the telescope mode, and the light amount is controlled by the shutter means 43b.

FIG. 6 shows a fourth embodiment of the present invention. The configuration of the camera is the same as that of the third embodiment shown in FIG. Regarding the block circuit for its operation, the telescope mode information 35b is further input to the OR circuit 37 in the first embodiment, and the first 38 and the timer 38 between the output side of the OR circuit 37 and the second analog switch 40 are connected. Instead of the analog switch, an integration means 45, an integration value comparison means 46, and a reference integration value 47 are connected, and the output side of the integration value comparison means 46 is connected to the second analog switch 40 and the input side of the OR circuit 49. , OR circuit 49
The reset switch 48 is connected to its input side, and the AND circuit 50 is connected to its output side. Further, the AND circuit 50 has its input side connected to the forced non-operation means 41, and its output side. Is connected to the second analog switch 40. Further, an eyepiece diaphragm 43c including an eyepiece diaphragm 77 is used instead of the diaphragm means 43a.

In this embodiment having the above-mentioned structure, the input to the OR circuit 37 is the photometric value comparing means 33 and the zoom information 35.
a, the telescope mode information 35b, and the OR circuit 37 outputs only when the condition that most affects the pupil, the high brightness object, the zoom telephoto, and the telescope mode. The time of the output is measured by the integrating means 45, and the integrated value comparing means 46
Is compared with the reference integrated value 47, and the light amount is controlled only when the reference value is exceeded. The light amount control is released by the reset switch 48 provided in the camera. Reset switch 48 is OR
The circuit 49 activates only when the output of the OR circuit 37 is present. Further, since the forced non-actuating means 41 is connected by the AND circuit 50, the analog switch 40 is turned off and the light amount control is canceled when either one of them is actuated.

FIG. 7 shows a fifth embodiment of the present invention. The configuration of the camera is the same as that of the third embodiment shown in FIG. In this embodiment, FIG. 6 of the fourth embodiment described above is used.
In place of the reset switch 48 in the block circuit diagram of FIG. 3, the output signals from the posture sensor 81 and the reference posture value 83 are input to the posture value comparison means 82 in order to perform the light amount control using the posture sensor, and the posture value comparison means 82 is compared. The output end of the means 82 is connected to one input end of the OR circuit 49, the outputs of the attitude sensor 81 and the OR circuit 37 are input to the sample hold (S / H) circuit 84, and the output thereof is the reference attitude value 83. Has been entered in. Also, the eyepiece diaphragm means 43
It is the same as the above-mentioned fourth embodiment except that c is the eyepiece shutter means 43c.

In the present embodiment having the above-described structure, the output of the attitude sensor 81 is output by the attitude value comparing means 82 to the reference attitude value 8
3, the analog switch 40 is turned off by the output, and the light amount control is released. As the reference posture value 83, the output of the posture sensor 81 when the photographer looks at a high-luminance subject is held by the S / H circuit 84, and this value is set as the reference posture value 83. When the photographer changes the direction of the camera from the high-brightness subject, the attitude (direction of the camera) changes from that when the high-brightness object is viewed, and the analog value 40 is output by the attitude value comparison means 82 and the analog switch 40 is turned off.

FIG. 8 shows a sixth embodiment of the present invention. The configuration of the camera is the same as that of the third embodiment shown in FIG. While the light amount control is performed by some means in the first to fifth embodiments, the present embodiment merely informs the photographer by the warning means. In this embodiment,
The reset switch 48, the OR circuit 49, the AND circuit 50, the eyepiece diaphragm means 43c, and the finder light quantity control means operation display 44 in the block circuit diagram of FIG. Output signal of the analog switch 4
The warning means 43d is connected to the output side of 0. The other points are the same as those in the fourth embodiment. As the warning means 43d, known means such as display in the finder, warning sound, etc. are used.

FIG. 9 shows a seventh embodiment of the present invention. The configuration of the camera is the same as that of the third embodiment shown in FIG. In this embodiment, in the camera shown in FIG. 4 which has a function of preventing camera shake in the optical system (camera shake), the light amount is controlled by utilizing this function. In the present embodiment, the output side of the analog switch 40 and the attitude sensor 81 is connected to the correction optical system 85 as a part of the camera shake prevention function in addition to the warning means 43d in the block circuit diagram of FIG. 8 of the sixth embodiment. There is. Other than that is the same as the sixth embodiment.

In this embodiment having the above construction, when the photographer sees a high-brightness subject, the correction optical system 85 is operated to forcibly shift the subject and control the amount of light entering the viewfinder.

Now, a camera shake prevention function including the posture sensor 81 and the correction optical system 85 will be described. With modern cameras, all important tasks for shooting, such as exposure determination and focus adjustment, are automated, so it is extremely unlikely that even an inexperienced person will make a shooting failure, but shooting due to camera shake Only failure was difficult to prevent automatically. Cameras that prevent shooting failures due to camera shake have been eagerly studied in recent years, and particularly cameras for the purpose of preventing shooting failures due to camera shake of the photographer have been developed and researched.

The hand shake of the camera when is the vibration of the normal IH _Z to 12H _Z as a frequency, at the release time of the camera shutter enable such camera shake even taking a photograph without image blur have caused the As a basic idea for doing so, it is necessary to detect the vibration of the camera due to the hand shake and displace the correction lens according to the detected value. Therefore, in order to achieve the above-mentioned object (that is, a photograph can be taken without causing image blur even if the camera shakes), firstly, the vibration of the camera is accurately detected and the optical axis change due to the camera shake is corrected. Will be required.

In principle, this vibration (camera shake) is detected by a vibration sensor for detecting angular change, angular acceleration, angular velocity, etc., and the sensor signal of the sensor is integrated electrically or mechanically to determine the angular displacement. This can be performed by mounting the output camera shake detection system (posture sensor 81) on the camera. Then, based on this detection information, the correction optical mechanism that decenters the photographing optical axis is driven to suppress the image blur.

Therefore, an image blur suppressing system using the angular displacement detecting device will be outlined with reference to FIG. In the illustrated example, the camera vertical shake 101 in the direction of the arrow 101 is shown.
This is to suppress the image blur caused by p and the camera lateral blur 101y. In the figure, 102 is a lens barrel, 1
Reference numerals 03p and 103y denote angular displacement detection means for detecting the vertical displacement of the camera and the lateral displacement of the camera, respectively, and the respective angular displacement detection directions are indicated by 104p and 104y. 105
Is a correction optical means, which is a coil 106 that gives thrust to the correction optical means.
p, 106y and position detection sensor 1 for detecting the position thereof
It has 07p and 107y. Further, the correction optical means 105 is provided with a position control loop, which will be described later, and is driven with the outputs of the angular displacement detection means 103p and 103y as target values to ensure stability on the image plane 108.

11 to 15 show the construction of an angular displacement detecting means (corresponding to the attitude sensor 81) suitable for the purpose of the attitude sensor. In the figure, 111
Is a main plate to which each component constituting the angular displacement detecting means is attached,
An outer cylinder 112 has a chamber in which the floating body 113 and the liquid L are enclosed. Reference numeral 113 denotes a floating body rotatably held by a floating body holding body 114 on a shaft 113a, which is made of a material composed of a permanent magnet and is magnetized in the direction of the shaft 113a.
A slit-shaped reflecting surface is formed on the protrusion 113b. Further, the floating body 113 is configured so that the rotation balance around the shaft 113a and the buoyancy balance are balanced.

Reference numeral 114 denotes a floating body holder fixed to the outer cylinder 112 while holding the floating body 113 via a pivot bearing 115, which will be described later. Reference numeral 116 denotes a U-shaped yoke attached to the main plate 111. Together with this, it forms a closed magnetic circuit. A winding coil 117 is arranged between the floating body 113 and the yoke 116 and is fixedly provided to the outer cylinder 112. Reference numeral 118 denotes a light emitting element (IRED) that generates light when energized, and is attached to the main plate 111.
Reference numeral 119 denotes a light receiving element (PSD) whose output changes depending on the position of the received light, which is also attached to the main plate 111. Then, the light emitting element 118 and the light receiving element 11
Reference numeral 9 constitutes an optical angular displacement detection means of a system that transmits light via the reflecting surface 113a of the floating body 113. 12
Reference numeral 0 denotes a mask arranged on the front surface of the light emitting element 118, which has a slit hole 120a for transmitting light. A stopper member 121 is attached to the outer cylinder 112 and regulates rotation of the floating body 113 so that the floating body 113 does not rotate beyond a predetermined range.

The rotatably holding of the angular displacement detecting means is performed as follows. That is, as shown in FIG. 12, a pivot 122 having a sharp tip in the vertical direction is press-fitted in the center of the floating body 113, while the tips of the U-shaped upper and lower arms of the floating body holding body 114 pivot inwardly facing each other. A bearing 115 is provided, and the sharp end of the pivot 122 is fitted into the pivot bearing 115 to hold the floating body 113. Reference numeral 123 denotes an upper lid of the outer cylinder 112, which is seal-bonded by a well-known technique using a silicone adhesive or the like to seal the liquid in the outer cylinder 112.

In the angular displacement detecting means having the above construction, the floating body 113 does not generate a rotation moment under the influence of gravity in any posture, and the floating shaft 113 rotates around the rotation shaft 113a so that a load is not substantially applied to the pivot shaft. In addition to being symmetrical with respect to the liquid L, the liquid L is made of a material having the same specific gravity. In reality, it is impossible to say that the unbalance component is zero, but since the shape error component acts as an unbalance only by the difference in specific gravity, it is practically sufficiently small, and the SN ratio of friction against inertia is extremely good. Is easy to understand.

In such a structure, even if the outer cylinder 112 rotates around the rotary shaft 113a, the internal liquid L remains stationary with respect to the absolute space due to inertia, so the floating body 113 in the floating state does not rotate, and therefore Outer cylinder 112 and floating body 113
Will rotate relative to the rotating shaft 113a.
These relative angular displacements can be detected by an optical detecting means using the light emitting element 118 and the light receiving element 119.

Therefore, the angular displacement is detected by the device having the above-mentioned structure as follows. First, the light emitted from the light emitting element 118 is transmitted through the slit hole 120 a of the mask 120.
The floating body 113 is irradiated with the light and is reflected by the slit-shaped reflecting surface of the protrusion 113b and is received by the light receiving element 119. When transmitting this light, the light is transmitted through the slit hole 12
0a and the slit-shaped reflecting surface form almost parallel light, and an image without blur is formed on the light receiving element 119.

Since the outer cylinder 112, the light emitting element 118, and the light receiving element 119 are all fixed to the base plate 111 and move integrally, the outer cylinder 112 and the floating body 11 are not movable.
When a relative angular displacement motion occurs between No. 3 and No. 3, the slit image on the light receiving element 119 moves by an amount corresponding to the displacement. Therefore, the output of the light receiving element 119, which is a photoelectric conversion element whose output changes depending on the position of the received light, is an output proportional to the position change of the slit image, and the angular displacement of the outer cylinder 112 can be detected by using the output as information. it can.

By the way, as described above, the floating body 113 is made of a permanent magnet material having the same specific gravity as the liquid L, but it is constructed as follows, for example. Liquid L
When a fluorine-based inert liquid is used as a liquid, if a fine powder of a permanent magnet material (for example, ferrite) is used as a filler based on a plastic material and the content rate is adjusted, the volume content rate is around 8%. It is easy to make the specific gravity to be about 1.8. Floating body 1 with this material
After molding 13 or at the same time, when it is magnetized in the direction of the shaft 113a, the floating body 113 has a property as a permanent magnet.

The sectional view of FIG. 14 shows the floating body 113 and the yoke 1.
16 shows the relationship between 16 and the winding coil 117.
In the figure, the floating body 113 is magnetized in the direction of the axis 113a, and in the figure, the upper side is magnetized to the N pole and the lower side is magnetized to the S pole. A magnetic line of force from the N pole passes through the U-shaped yoke 116 and enters the S pole, forming a closed magnetic path. The winding coil 117 arranged in this magnetic path is from the back side to the front side as shown in the drawing. When an electric current is applied, the wound coil 117 receives a force in the direction of arrow f according to Fleming's left-hand rule. However, it goes without saying that the force is proportional to the current flowing through the winding coil 117, and the direction of the force acts in the opposite direction if a current is applied in the opposite direction. That is, with the above configuration, the floating body 113 can be freely driven.

The spring force exerted on the floating body 113 by this driving force is, in principle, a force that maintains the floating body 113 in a fixed posture with respect to the outer cylinder 112 (that is, moves integrally). When it is strong, the outer cylinder 112 and the floating body 11
3 causes a problem that relative angular displacement does not occur due to the intended angular displacement, but if the driving force (spring force) is sufficiently small with respect to the liquid inertia, it is relatively low. It can be configured to respond to angular displacement of frequency.

FIG. 15 shows an electric circuit for operating the angular displacement detecting means having the above construction. Amplifiers 124a and 124b
Converts the photocurrent generated in the light receiving element 119 by the reflected light h of the light emitting element 118 into a voltage, and the amplifier 125
The output difference between 4a and 124b, that is, the angular displacement (the relative angular displacement movement between the outer cylinder 112 and the floating body 113) is obtained. This output is divided by resistors 126 and 127 into an extremely small output, and a drive amplifier 128 which allows a current to flow through the coil 117.
To the negative feedback (when the amplifier 125 outputs, the floating body 11
The wiring of the coil 117 and the floating body 11 so that 3 returns to the center.
3) is set), a spring force (driving force) sufficiently smaller than the inertia of the liquid is generated as described above.

The amplifier 129 is the amplifiers 124a and 124b.
Sum (reflected light h from the light emitting element 118 of the light receiving element 119)
Total amount of received light) of the light emitting element 11
8 is input to the drive amplifier 130 that emits light.
Although the light emitting element 118 changes its light emission amount extremely unstablely with respect to temperature and the like, if the light emitting element 118 is driven by the total light receiving amount as described above, the total photocurrent output from the light receiving element 119 is always constant. The angular displacement detection sensitivity of the amplifier 125 can be extremely stable.

16 to 18 show a servo angular acceleration sensor suitable for this purpose as another attitude sensor. In FIG. 16, reference numeral 131 denotes an outer frame bottom portion, and a support portion 132 integrally fixed to the outer frame bottom portion 131.
Both ends of the shaft 134 are supported by bearings 133 having low friction such as a ball bearing.
A seesaw 136 to which coils 135a and 135b are attached is rockably supported by 34. Above and below the coils 135a and 135b and the seesaw 136, the magnetic circuit board as the lid portions 137a and 137b and the permanent magnets 138a ₁ , 138a ₂ , 138b ₁ and 1 are separated from them.
38b ₂ are arranged so as to face each other, and the magnetic circuit board also serves as the lid of the outer frame as described above. The permanent magnets 138a ₁ , 138a ₂ , 138b ₁ and 138b ₂ are magnetic circuit back plates 139 fixed to the outer frame bottom 51, respectively.
a, 139b.

A slit plate 140 forming a slit 140a penetrating in the thickness direction is provided above the coil 135a of the seesaw 136.
The lid portion 137a that also serves as the magnetic circuit board above the 40a has an S
A photoelectric displacement measuring device 141 made of PC (Separate Photo Diode) or the like is arranged, and a projector 142 made of an infrared light emitting diode or the like is arranged on the magnetic circuit back plate 139a below the slit 140a.

In the servo angular acceleration sensor having the above configuration, if the angular acceleration a acts on the outer frame as indicated by the arrow b, the seesaw 136 tilts relatively in the direction opposite to the angular acceleration a. The deflection angle can be detected by the position on the displacement measuring device 141 of the beam from the light projector 142 via the slit 140a.

By the way, the permanent magnets 138a ₁ and 138
The magnetic fluxes from b ₁ are the permanent magnets 138a ₁ and 138b, respectively.
₁ → coil 135a, 135b → magnetic circuit board 137a,
137b → coils 135a, 135b → permanent magnet 138
a ₂ and 138b ₂ and the other permanent magnets 138a ₂ and 138b ₂
From the permanent magnets 138a ₂ and 138b ₂ →
Magnetic circuit back plates 139a, 139b → permanent magnet 138
A closed magnetic circuit is formed as a whole by passing through a ₁ and 138b _1, and a magnetic flux in a direction perpendicular to the coils 135a and 135b is formed. And the coil 13
By providing a control current to 5a and 135b, the seesaw 136 can be moved to both sides along the swing direction of the angular acceleration a according to Fleming's law.

FIG. 17 shows an example of an angular acceleration detection circuit used in the servo angular acceleration sensor having the above-mentioned structure. This circuit further includes a displacement detection amplifier 143 for amplifying the output from the displacement detector 141, a compensation circuit 144 for making this feedback circuit a stable circuit system, and an amplified output from the displacement detection amplifier 143. A drive circuit 145 that amplifies current and energizes the coils 135a and 135b, and the coils 135a and 135b are connected in series. In this example, when the coils 135a and 135b are energized, the seesaw 13 by the external angular acceleration a is applied.
The winding direction of the coils 135a and 135b and the permanent magnet 138 so that a force is generated in the direction opposite to the deflection direction of the coil 6.
The polarities of a ₁ , 138a ₂ , 138b ₁ and 138b ₂ are set.

Next, the operation principle of the servo angular acceleration sensor having the above configuration will be described. Now, if an angular acceleration a is applied from the outside to the angular acceleration sensor having the above configuration, the seesaw 1
36 swings in the opposite rotational direction relative to the outer frame due to the inertial force, so that the slit 140a provided in the seesaw 136 moves in the L direction. For this purpose, the projector 14
The center of the light flux incident on the displacement detector 141 from 2 is displaced, and an output proportional to the displacement amount is generated from the displacement detector 141. The output is the displacement detection amplifier 14 as described above.
3 is amplified by the drive circuit 145, and the current is further amplified by the drive circuit 145, and the coils 135a and 135b are energized.

When a control current is applied to the coils 135a and 135b as described above, a force is generated in the seesaw 136 in the R direction, which is the opposite direction to the L direction of the external angular acceleration a, and the displacement detector is detected. The control current is adjusted and generated so that the light beam incident on 141 returns to the initial position when the external angular acceleration a is not applied. At this time, the coils 135a, 1
The value of the control current flowing through 35b is proportional to the rotational force applied to the seesaw 136, and the rotational force applied to the seesaw 136 is proportional to the force for returning the seesaw to the origin, that is, the magnitude of the external angular acceleration a. By reading the current as the voltage V through the resistor 146, the magnitude of the angular acceleration a as the control information necessary for the image blur prevention system of the camera or the like can be obtained. Then, the obtained angular acceleration output is integrated twice by a known analog integrator or digital integrator and converted into an angular displacement output to be a shake output.

The circuit diagram of FIG. 18 shows the angular accelerometer detection circuit of FIG. 17 more specifically. In FIG.
The amplification amplifier 147 corresponds to the displacement detection amplifier 143 in FIG. 17, and converts the photocurrent from the displacement measuring device 141 into a voltage and amplifies it to perform position detection. The resistors 148 and 149 and the capacitor 150 correspond to the compensation circuit 144 in FIG. 17, and the drive amplifier 152 drives the coils 135a and 135b and corresponds to the drive circuit 145 in FIG.

Next, FIGS. 19 and 20 show the structure of the correction optical means suitable for such a system. In FIG.
The correction lens 161 can be freely driven in two directions (pitch 162p and yaw 162y) perpendicular to each other orthogonal to the optical axis, and the fixed frame 163 holding the correction lens 161 slides on a polyacetal resin (hereinafter referred to as POM) or the like. Bearing 1
It can slide on the pitch slide shaft 165p via 64p. Also, pitch slide shaft 165p
Are attached to the first holding frame 169. The fixed frame 163 is sandwiched by pitch coil springs 166p coaxial with the pitch slide shaft 165p and held near the neutral position. Further, a pitch coil 167p is attached to the fixed frame 163, and the pitch coil 167p is placed in a magnetic circuit composed of a pitch magnet 170p and a pitch yoke 171p.
3 is driven in the pitch direction 162p. The pitch coil 167p is provided with a pitch slit 168p, and the projector 172p (infrared light emitting diode IRED) is provided.
The position of the fixed frame 163 in the pitch direction 162p is detected by the relation between the light receiving device 173p and the semiconductor light receiving device PSD.

A slide bearing 164y such as POM is fitted to the first holding frame 169, and the yaw slide shaft 16
It can slide on the housing 174 to which 5y is attached. Since the housing 174 is attached to the lens barrel, the first holding frame 169 can move in the yaw direction 162y with respect to the lens barrel. Further, a yaw coil spring 166y is provided coaxially with the yaw slide shaft 165y and is held near the neutral position like the fixed frame 163. Further, the fixed frame 163 is provided with a yoke coil 167y, and the fixed frame 163 is also driven in the yaw direction 162y in association with the yoke magnet 170y and the yaw yoke 171y sandwiching the yoke coil 167y. Yaw coil 167y
Is provided with a yaw slit 168y, and the position of the fixed frame 163 in the yaw direction 162y is detected similarly to the pitch direction.

Then, in FIG. 19, the light receiver 173
The outputs of p and 173y are amplified by amplifiers 175p and 175y, and the coils (pitch coil 167P, yaw coil 167) are amplified.
y), the fixed frame 163 is driven and the light receiver 17
The outputs of 3p and 173y change. Where the coil 16
The drive direction (polarity) of 7p and 167y is set to the light receiver 173p,
When the output of 173y is set to be small (negative feedback), a closed system is formed, and the outputs of the photodetectors 173p and 173y are stabilized at a point of almost zero.

Here, the compensating circuits 176p and 176y are circuits for stabilizing the system shown in FIG.
p and 177y are circuits for compensating the current applied to the coils 167p and 167y. When command signals 178p and 178y are externally applied to such a system, the correction lens 16
1 is driven extremely faithfully to the command signal in the pitch direction 162p and the yaw direction 162y. Such a method of driving the position output by negatively feeding back to the coil is called position control drive, and the closed system is called a closed loop system. In addition, the command signal 178
When the outputs of the angular displacement detectors 103p and 103y in FIG. 10 are input as p and 178y, respectively, the correction lens 1
Reference numeral 61 is faithfully driven based on its output, that is, the correction lens 161 is driven according to camera shake, so if the shake direction and the correction lens drive direction are adjusted according to the optical characteristics of the correction lens, image stabilization is performed. Will be seen.

FIG. 20 is a concrete drive circuit diagram for driving the correction optical means. Here, only the pitch direction will be described. Current-voltage conversion amplifiers 179a and 179
b converts the photocurrent generated in the light receiver 173p by the light projector 172p into a voltage, and the differential amplifier 180 obtains the difference between the current-voltage conversion amplifiers 179a and 179b, which represents the position of the correction lens 161 in the pitch direction 162p. The current-voltage conversion amplifiers 179a and 179b and the differential amplifier 180 correspond to the amplifier 175p in FIG. The command amplifier 182 adds the command signal to the output of the differential amplifier 180, and the coil 167p corresponding to the drive circuit and the drive amplifier 1
Input to 86 to drive the correction lens 161. Resistance 1
83, 184 and the capacitor 185 are well-known phase advance circuits and correspond to the compensation circuit 176p in FIG. 19 and stabilize the system. The summing amplifier 181 is the sum of the outputs of the current-voltage conversion amplifiers 179a and 179b (the total amount of light received by the light receiver).
Is calculated, and the output is obtained by the projector 172p and the drive amplifier 187.
To enter. The projector 172p changes its projection amount extremely unstablely with respect to temperature and the like, and the position sensitivity of the differential amplifier 180 changes accordingly. However, if the projector is controlled so that the total amount of received light is constant as described above, the position sensitivity will change. It doesn't change.

FIG. 21 is a block diagram of correction optical means using a variable apex angle prism. In the figure, 191 is a liquid having a high refractive index, for example, a silicon-based liquid, and includes two flat glass plates 192p and 192y and a polyethylene film 193.
It is sealed without bubbles by. This flat glass 192
p is held by a pitch holding frame 194p, the pitch holding frame 194p is rotatably supported around a pitch shaft 195p, and the plane glass 192y is a yaw holding frame 194y.
The yaw holding frame 194y is supported around the yaw shaft 195y.

The pitch holding frame 194p and the yaw holding frame 19
4y has a pitch coil 196p and a yaw coil 1 respectively.
96y is provided, and these coils are respectively fixed pitch magnet 197p and yaw magnet 19
7y and the pitch yoke 198p and the yaw yoke 198y are placed in a closed magnetic circuit, so that the pitch yoke 19
The pitch holding frame 194p and the yaw holding frame 194y are rotationally driven around the pitch axis and the yaw axis, respectively, by passing currents through the 8p and the yaw yoke 198y, respectively.

Further, the arm 199 of the pitch holding frame 194p
Displacement detection light receiving elements 200p and 200y are attached to the arm 199y of the p and yaw holding frame 194y, respectively, and these are fixed infrared light emitting elements 201p and 201y.
The pitch rays 195p and the yaw axis 19 are respectively generated by the squeezed rays emitted from y through the holes 202p and 202y.
Rotation around 5y is detected. This displacement detection light receiving element 20
0p, 200y, pitch coil 196p, yaw coil 1
The known position control is also carried out with respect to 96y, as described above with respect to the slide type correction optical means.

When the pitch holding frame 194p is rotated about the pitch axis 195p and the plane glass 192p is tilted about the pitch axis 195p in the correction optical means having the above-described structure, a light ray passing through the liquid 191 having a high refractive index is indicated by an arrow 162y. Eccentric to the yaw axis 19 and the yaw holding frame 194y moves toward the yaw axis 19
It rotates around 5y, and the flat glass 192y moves to the yaw axis 195.
When tilted around y, the ray is eccentric in the direction of arrow 162y. The greatest feature of such a variable apex prism is that the optical axis can be decentered regardless of the optical system in front of and behind the variable apex prism in the optical axis direction. It is possible to correct the optical axis even if it is attached to the front of the.

[0057]

As described above, according to the present invention, the finder light amount control means for reducing or blocking the amount of light incident on the photographer's pupil as the subject brightness increases, is surely protected. There is an effect that can be done.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a camera including a finder light amount control means according to a first embodiment of the present invention.

FIG. 2 is a block circuit diagram for the operation of the camera.

FIG. 3 is a schematic sectional view of a camera of a second embodiment of the present invention.

FIG. 4 is a schematic sectional view of a camera of a third embodiment of the present invention.

FIG. 5 is a block circuit diagram for its operation.

FIG. 6 is a block circuit diagram for operating a camera according to a fourth embodiment of the present invention.

FIG. 7 is a block circuit diagram for operating the camera of the fifth embodiment of the present invention.

FIG. 8 is a block circuit diagram for operating a camera according to a sixth embodiment of the present invention.

FIG. 9 is a block circuit diagram for operating a camera according to a seventh embodiment of the present invention.

FIG. 10 is a schematic configuration diagram of an optical system having a vibration isolation system.

FIG. 11 is a lateral cross-sectional view of a main part of an angular displacement detection device in the vibration isolation system.

FIG. 12 is a vertical sectional view of the same.

FIG. 13 is a perspective view of the same main portion.

FIG. 14 is a cross-sectional view of relevant parts for explaining the operating state of the same.

FIG. 15 is an electric circuit diagram for the same operation.

FIG. 16 is an exploded configuration diagram of a servo angular acceleration sensor for another vibration isolation system.

FIG. 17 is likewise a block circuit diagram of a main part for its operation.

FIG. 18 is an electric circuit diagram for the same operation.

FIG. 19 is an exploded configuration diagram of a correction optical unit suitable for an image stabilization system.

FIG. 20 is an electrical circuit diagram for its operation.

FIG. 21 is a configuration diagram of a correction optical unit using another variable apex angle prism.

FIG. 22 is a schematic perspective view of a conventional finder optical system telescope switchable camera.

[Explanation of symbols]

F ・ ・ Film, 21,61,71 ・ ・ Photo lens, 2
2, 62, 72 ··· Finder eyepiece, 23 · · Aperture, 25 · · Penta prism, 26, 65, 77 · · Eyepiece shutter or eyepiece diaphragm, 27, 66,
79 .. Photometric sensor, 63, 73 .. Shutter that also serves as an aperture, 64, 76 .. Viewfinder optical system, 31 .. Camera main switch. 32 .. Photometric means, 33 .. Photometric value comparison means, 35a .. Zoom information, 35b .. Telescope mode information, 41 .. Forced non-operation means, 42 .. Forced non-operation means operation display, 43a .. Aperture means , 43b .. Shutter means, 43c .. Eyepiece diaphragm means, 44 .. Viewfinder light quantity control means operation display, 48 .. Reset switch, 81 .. Attitude sensor.

Claims (17)

[Claims] 1. A camera provided with a finder light amount control means for controlling the light amount incident on a photographer's pupil to decrease or not to enter as the subject brightness increases. 2. The camera according to claim 1, wherein the finder light quantity control means is a diaphragm control means provided in a lens barrel having a photographic lens built therein and narrowing down the light incident on the photographic lens. 3. The camera according to claim 1, wherein the finder light amount control means is a shutter means which is provided in a lens barrel having a photographic lens built therein and blocks light incident on the photographic lens. 4. The camera according to claim 1, wherein the finder light amount control means is an eyepiece diaphragm control means that is provided in a finder lens group forming a finder optical system and narrows down light incident on the finder lens. . 5. The camera according to claim 1, wherein the finder light amount control means is an eyepiece shutter means included in a finder lens group forming a finder optical system and blocking light incident on the finder lens. 6. The camera according to claim 1, wherein the finder light amount control means is activated when the subject brightness is high for a desired time or longer. 7. The camera according to claim 1, wherein the taking lens has a zoom mechanism, and the finder light amount control means operates only when the focal length is long by the zoom mechanism. 8. The finder optical system can be used as a telescope by changing at least one of the finder lenses, and the finder light quantity control means operates only when the telescope is used. camera. 9. A photometric means for measuring subject brightness,
2. The camera according to claim 1, wherein the photometric means measures the subject brightness at regular intervals from the time when the main switch is turned on, and controls the finder light quantity control means by the output of the photometric means. 10. The camera according to claim 1, further comprising a forced non-operation means for forcibly deactivating the finder light amount control means. 11. The camera according to claim 10, wherein the forced non-operation means is set by turning off a camera main switch. 12. The camera according to claim 1, further comprising notification means for notifying a photographer that the finder light amount control means is operating. 13. The camera according to claim 1, further comprising reset means for releasing the operation of the finder light quantity control means. 14. The camera according to claim 13, wherein the reset means is a time control means for resetting the operation of the finder light amount control means at regular time intervals. 15. The reset means is an operation member operable by a photographer.
The listed camera. 16. The reset means is an attitude sensor provided in a camera, and resets the operation of the finder light quantity control means when the attitude sensor output changes after the operation of the finder light quantity control means. The camera according to claim 13. 17. A lens barrel portion for holding a taking lens having one optical axis, and a drivable correction optical system for decentering the optical axis relative to the lens barrel portion, the lens barrel portion comprising: A camera characterized in that the correction optical means is a finder light amount control means which operates when it is expected that an abnormality will occur in a photographer's pupil due to an increase in subject brightness.