JP2002148685A - Pan tilt camera, and mirror unit for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera mirror unit for preventing the occurrence of image blurring, as for a camera for continuously photographing a moving image in plural various positions in an mage pickup direction. SOLUTION: As for the camera provided with an image pickup means or picking up the image of an object, a lens for forming the image on the image pickup means, a mirror arranged ahead of the lens so as to change the image pickup direction and a driving means for driving the mirror so as to change the direction of the mirror, the driving means is provided with a coil for generating a magnetic field corresponding to a current, a permanent magnet arranged facing the coil, and a displacement sensor such as a Hall element for detecting the relative displacement between the coil and the permanent magnet. Besides, it is allocable that the driving means is composed of a piezoelectric element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pan-tilt structure of a camera, and in particular, drives a mirror mounted on an internal image pickup system to change the image pickup range of the camera up and down even if the entire apparatus is not movable. Related to the technology that can be changed left and right.

2. Description of the Related Art The handling of digital images has become easier with the spread of personal computers and the like. Along with this, photography of landscapes and people used to be mainly performed on a silver halide type film, but digital cameras and digital video cameras that capture the landscape in a precise digital form have become widespread.
In such a camera, an electric signal is obtained by a photoelectric conversion element for converting incident light into electric charge by digital processing, and is converted into a data format that can be used by a subsequent device, for example, an image monitor device or a computer. For example, in Japan NTS
C (National Television Sys)
tem Committee) system, PAL (P
case Alteration Line Met
(hod) format such as a standard used in television or the like, or a digital standard interface that is easily connected to digital equipment such as a computer, for example, USB
(Universal Serial Bus), IEEE
E1394 standard or the like is used. A circuit for converting such a signal is mainly a circuit for level correction of an image signal obtained from a photoelectric conversion element (imaging element), and a circuit for balancing colors if the photoelectric conversion element is a color, for a pan-tilt camera. Built in the casing.

FIG. 15 is a diagram of a conventional example. Although the entire camera is omitted, a lens 10 for forming an image of a subject on an image pickup device (CCD) 12 and a substrate 1
The lens barrel 11 supported on the camera 3 is fixedly mounted on a camera frame from which the lens barrel 11 is omitted. On the other hand, a mirror 20 capable of changing the reflection direction is mounted in front of the lens 10 in the imaging direction. The mirror 20 is supported such that a shaft 21 for rotating in the X-axis direction is rotatable by a frame 22. The shaft 21 is connected to the motor 2 via a gear train 23 on one side.
4, the mirror is rotated around the X axis by the driving of the motor 24.

[0003] Since the support column 25 is connected to the motor 27 via the gear train 26 at substantially the center below the frame 22, the support column 25 can rotate in the Y-axis direction with respect to the fixed flange 28. Although not visible in the figure, the shaft 21 and the pointing post 2
5 is provided with a position sensor, and a control circuit for stopping and starting according to this signal is prepared.

[0004] The use of a camera capable of changing the image pickup direction in this way will be briefly described. For example, there is a surveillance camera that monitors an environmental condition in a room or outdoors, or monitors a store or the like for fraud. In a conventional surveillance camera, a sufficiently large imaging lens is required because an image of a wide area must be taken, so that the entire camera is configured to be vertically movable.

There is also a simple conference system which covers a small area, for example, by connecting to a computer or a digital television. The camera used in these systems is an inexpensive camera, because image problems such as image distortion may be somewhat tolerated. In this case, the imaging range (orientation) is often set manually, but the one that can be moved electrically can be set on a drive platform called a pan head, or the one described in Japanese Patent Application Laid-Open No. H10-341370.
In some cases, a part of the casing is made movable and a drive is provided inside the casing as disclosed in US Pat. Further, in an application in which image distortion may be large, such as a so-called door phone which is mounted on a door of a home and monitors the state of a visitor, for example, an image pickup device for performing image pickup disclosed in Japanese Patent Application Laid-Open No. 11-231371 In some cases, the imaging range is changed by moving the lens while fixed.

[0006] The method of swinging the entire camera up, down, left and right (in the pan and tilt directions) requires a considerably large driving force, and thus consumes a large amount of power. It was impossible to change the shooting direction quickly because of the large weight.

To solve this problem, Japanese Patent Laid-Open No. Hei 7-170434 discloses a method for changing the photographing direction by controlling two axes by using a mirror for reflecting and projecting a subject.

[0008]

It is true that this method of controlling the position of the mirror is very effective because the weight of the mirror is small. However, the method described with reference to FIG.
In this method, the rotation of a rotating shaft of a C motor or the like is changed to drive for changing the mirror direction by deceleration by a gear, and there is a problem that the rotating image is blurred without the gear moving smoothly.
Although there are few problems when taking a still image at a plurality of positions where the imaging direction is changed, there is a problem with image blurring during continuous shooting of moving images.

[0009]

In order to solve this problem, an image pickup means for picking up an image of a subject, a lens for forming an image on the image pickup means, and a mirror installed in front of the lens for changing the image pickup direction are provided. A driving means for changing the direction of the mirror, the driving means comprising: a coil for generating a magnetic field in accordance with a current; a permanent magnet opposed to the coil; The camera is provided with a displacement sensor for detecting a relative displacement with respect to the permanent magnet.

[0010] Further, an image pickup means for picking up an image of a subject, a lens for forming an image on the image pickup means, a mirror installed in front of the lens to change the image pickup direction, and a drive means for changing the direction of the mirror for driving. A camera with
The driving means is a camera including a coil for generating a magnetic field in accordance with an electric current, a cylindrical permanent magnet magnetized in a diameter direction, and an axis for rotatably supporting the permanent magnet.

Further, an image pickup means for picking up an image of a subject, a lens for forming an image on the image pickup means, a mirror installed in front of the lens for changing the image pickup direction, and a drive means for changing the direction of the mirror for driving The driving means is a camera provided with a piezoelectric element.

And an image pickup means for picking up an image of a subject, a lens for forming an image on the image pickup means, a mirror installed in front of the lens for changing the image pickup direction, and a drive means for changing the direction of the mirror. Wherein the imaging casing holding the imaging means and the mirror casing holding the mirror and the driving means are detachably configured.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described with reference to FIG. 1 which is a simplified perspective view showing the concept and FIG. 2 which shows a side view of an internal unit. (Explanation of Imaging Unit) In FIG. 1 which is a perspective view of a unit built in the casing 1 of the camera, an imaging substrate 53 for performing imaging is shown.
And the processing substrate 55 for processing signals are fixed in the casing 1 so as to obliquely face the mirror surface 70a of the mirror 70. A lens barrel 50 that encloses and fixes a lens 51 is mounted on the imaging substrate 53 so as to cover a CCD (image sensor) 52.

The image signal obtained from the CCD 52 is weak and easily affected by noise.
After lowering the impedance with an Emitto follower transistor (not shown) and increasing the noise resistance,
The flexible circuit 54 allows the signal processing board 5
Passed to 5.

The CCD 52 has a voltage of 30 V, 15 V, 5 V,
Since a large voltage such as -8 V is required, a voltage is generated on the signal processing board 55 and then passed to the imaging board 53 via the flexible circuit 54. If this camera has a power supply, it will be generated from a 100V commercial power supply.
(For example, 5V) using an inverter power supply.

Further, in order to improve the ground impedance in addition to the above noise countermeasures, means for alternately arranging signal lines and ground lines is also used. The frame 60 to which the imaging substrate 53 is fixed is integrally formed with frames 61 and 62 on which the operating mirror 70 and its driving mechanism are mounted, and is fixed to the camera casing 1.

The CCD 52 has two-dimensionally arranged photodiodes of a number corresponding to the resolution (resolution). A lens 51 for irradiating the photodiode group with light and a CCD 5 are provided.
Since the positional relationship with the photodiode group arranged inside 2 is determined by the focal length of the lens 51 (the lens group in the lens barrel 50), the relative position is fixed so as not to change due to unintended external factors such as vibration. Further, a mirror part, which will be described in detail below, and an image pickup part including this image pickup element can be configured separately from each other. 1 and a second casing for holding the imaging unit, and if these are designed to be united or exchangeable, a unit having a different pixel of the CCD 51 or a unit having a different angle of view of the lens is series. Product groups.

With this configuration, the development of the mirror unit can be made common and the cost can be reduced.

(Explanation of Mirror) The subject is reflected by the reflecting surface 70a of the mirror 70 and forms an image on the CCD 52 of the image pickup unit.
Since the mirror 70 has aluminum evaporated on the surface, the surface is a reflection surface. Since the Tilt operation fulcrum (P) is within the reflection surface and the optical center axis (Z) of the lens 51 projected onto the CCD 52 passes through the P fulcrum, the lens always rotates even when the mirror rotates about the P fulcrum. The optical center axis (Z) of 51 does not deviate from the P fulcrum. As shown in FIG.
The mirror 70 is at an image reference position of 45 ° with respect to the optical center of the lens 51, and performs a circling around + -20 ° around this position.

The following description is based on the assumption that the surface 1b of the casing 1 on the processing substrate 55 side is attached to a wall surface and the surface 1a is used as an upper side. For example, this camera is mounted on a wall near a door of a house and used as a door phone. By swinging the mirror in the up-down (tilt) direction and the left-right (pan) direction, it becomes possible to shoot regardless of the height and standing position of the visitor.

In the vertical direction, the imaging range is from point A1 to point A3. Since the angles of incidence on the mirror 70 at these two points are different, the photographed subject becomes trapezoidally distorted. This correction is performed by inputting a correction circuit on the processing board 55 or a video signal output from the camera. For example, correction can be performed by performing scaling processing by software such as a computer.

On the other hand, in the left-right direction for the subject with the mirror 70 facing forward, the imaging range is from point A2 to point A4. Since the angles of incidence on the mirror 70 at these two points do not differ, the photographed subject is not distorted into a trapezoid. However, since the same phenomenon occurs when the camera shakes in the left-right direction, a correction process is required.

In FIG. 1, the image pickup area on the mirror 70 is indicated by an ellipse passing through A1, A2, A3, and A4 because the lens 51 is a circular projection and a circle corresponding to the effective diameter of the circle. Is inclined to form an ellipse. The rectangular area of the CCD 52 within the effective diameter range of the lens 70 is the imaging range.

Now, a pin 72 is inserted into portions 71a and 71b of the mirror folder (first folder) 71 for holding the mirror 70 in support of the mirror. The pin 72 serves as a pan (left-right direction) side rotation (swing) axis, and a tilt (up-down direction) side rotation in a direction perpendicular to this axis.
Mirror folder (first folder) 71, flange 75 of bread folder (second folder) to perform (haruka)
a and 75b are supported by a pin 72 so as to be rotatable (movable).

Mirror folder (first folder) 71
Is provided with a drive arm 76 on the surface opposite to the surface on which the mirror 70 is mounted. The crank pin 66a of the crank 66 engages with the slit hole 76a of the drive arm 76, and the crank 66 fits on the shaft 65b of the pan motor 65, so that the oscillating power of the pan motor 65 is transmitted.

The pan motor 65 is fixed to a pan folder (second folder) 75. A motor fixing flange 76 is provided on the surface of the pan holder 75 opposite to the mirror folder (first folder) 71. The pan motor 65 is fixed to the motor fixing flange 75c by a female screw and a male screw 77 cut in the mounting portion 65a.

On the other hand, in the same manner as the tilt motor 63, the crank pin 64a of the crank 64 is connected to the pan folder 75.
The pan folder 75 is operated in agreement with the pan driving arm 78 through the slit 78a. The tilt motor 63 is fixed to a fixing plate (not shown) connected to the fixing frames 61 and 62 with screws.

(Description of Structure of Pan / Tilt Motor) FIG. 3 shows the detailed structure of the motor. Since the pan motor 65 and the tilt motor 63 shown in FIGS. 1 and 2 have the same structure, the tilt motor will be described here. The description will be made with reference to the magnetic circuit diagram of FIG.

The rotor 83 located at the center of the tilt motor 63 is a permanent magnet. This rotor has a rotating shaft 8
6 and has a cylindrical shape having the same radius with respect to the rotating shaft 86. The magnetization direction is the radial direction, and the S pole and the N pole are formed at a certain radial direction as a boundary as shown in FIG. The upper bobbin 81 and the lower bobbin 82 are
Are rotatably fitted around the rotor 83 in the axial direction. A terminal pin 82a is integrally formed on the bobbin 82. Thereafter, a copper wire having an insulating film such as an enamel wire is wound around the bobbin 82 to form a coil 84. The ends of the windings are stripped off and soldered to the terminal pins 82a. Next, the upper lid 80 is mounted on the upper bobbin 81, a yoke 87 for forming a magnetic circuit is loaded from the opposite direction, and finally a substrate 85 is mounted to complete the motor.

The completed motor (tilt motor 63)
The shaft 86 is viewed from the upper lid 80 to the outside, and the crank 64 is pressed into this portion. The tilt motor 63 is provided with a mounting portion 63a which is threaded for mounting. Further, as shown in FIG. 4, a Hall element 90 for detecting that the rotor 83 has been displaced (angular displacement: rotational displacement) by detecting the magnetic flux density of the magnetic field is provided on the side surface of the rotor 83. I have. Since the magnetization direction of the rotor 83 is a radial direction as can be seen in FIG. 4, when the rotor 83 rotates around the shaft 86, the magnetic flux density of the component of the Hall element 90 in the direction perpendicular to the plane changes.

The lines of magnetic force shown in FIG. 4 indicate a state where the coil 84 is not energized. Although the coil 84 is depicted as being divided into two in FIG. 4, it is electrically cascaded and equivalent to one coil.

(Description of Motor Control) FIGS. 5 and 6 show the relationship between the rotation angle of the rotor and the output of the Hall element. FIG. 7 shows a servo circuit for controlling the position of the pan motor 65 and the tilt motor 63.

FIG. 5 shows the output voltage of the Hall element 90 according to the shaft deflection angle of the pan motor 65 and the shaft deflection angle of the tilt motor 63. The mounting position of the Hall element 90 is, as shown in FIG.
It is located at the boundary between the pole and the north pole. During actual assembly,
With the shaft 86 of the rotor 83 fixed at this position, the position of the crank 64 is adjusted so that the mirror 70 is at the initial position (the origin position of the pressure image range). The adjustment of the crank 64 is adjusted by changing a magnetic balance point by an electric balance adjustment described later. Pan motor 65
The same is true for

The reason why the mounting position of the Hall element 90 is located at the boundary between the S-pole and the N-pole of the rotor 83 is as shown in FIG. This is because the position (the position where the magnetic flux is 0 Gauss) has a substantially linear output characteristic before and after the position. If a linear output can be obtained, there is no need for correction when performing arithmetic control based on this output.

FIG. 7 shows a feedback (servo control) circuit for controlling the direction of the shaft 86 of the tilt motor 63, that is, the tilt direction of the mirror 70, using the output from the Hall element 90. Of course, the same applies to the pan motor 65.

The Hall element 90 operates with a bias voltage applied thereto, and the output terminal voltage is balanced by the potentiometers 95 and 96 and input to the amplifier 97. This amplifier 9
7 is input to the operation amplifier 99, and the terminal 98
And is applied to one end of the coil 84. The other end of the coil 84 is biased by the voltage from the amplifier 100. The coil 84 is divided into blocks and wound. However, as described above, it is assumed that the magnetic flux is generated almost linearly in the rotation range (approximately + -20 °) used, and the voltage applied to the signal input terminal 98 is also substantially equal. Given linearly.

In the above description, the Hall element is taken up as a magnetic sensor in any case. However, an active element, such as an MR element, which changes its electric resistance by magnetism or can detect even if the coil itself does not move, is used. A search coil may be mounted.

When a current flows through the coil 84, the magnetic field applied to the Hall element 90 sees the combined magnetic field of the magnetic field from the rotor 83 and the magnetic field from the coil 84. Since the position is very close to the rotor 83 and the coil 84 concentrates its magnetic flux in the direction of the rotor 83 due to the magnetic resistance, the magnetic field of the rotor 83 is detected with almost negligible accuracy. Become. In particular, when the rotor rotation angle is small, about + -20 °, the coil current is small, so that it can be approximated.

Instead of such an approximation, the Hall element 90
Can be once converted to digital, and a data table on a memory can be referred to by management of a CPU or the like, and nonlinear delicate control can be realized. The set digital value may be converted to analog again, or PWM (Puls
A current may be supplied to the coil as e Width Modulation.

(Explanation of First Modification) FIG. 8 shows a configuration using a laminated ceramic (piezo element). Camera frame 2
In 00, there are an imaging substrate 206 on which a photoelectric conversion element (CCD) 204 for imaging is mounted, and a lens 205 for imaging an object on the CCD 204. And this lens 205
In front of the camera frame 200, there is a mirror 223 for changing light from a subject outside the camera frame 200 and a drive unit thereof. The mirror 223 is fixed to the first folder 220 and the fulcrum 2
At 22, the second folder is movably supported.

A first arm 221 for transmitting the drive to a part of the first folder 220 is formed, and the tip of the first arm 221 receives the drive of the first piezo element 230.
It is connected to the lever 224. The first lever is 225 and 2
The fulcrum is supported at 26 angles. The second piezo element 210 drives the entire configuration up to the mirror 223 including the first piezo element 230 as described above.

An overhang portion 2 is provided at a part of the first folder 220.
20a, which is connected to the distal end portion 212a of the second arm 212 for expanding and transmitting the displacement of the second piezo element 210 so as to be able to move freely. The fulcrum pin 213 is rotatably attached to the angle 211 at a position close to the second piezo element 210 in the second arm, and a small displacement of the second piezo element is amplified to a practical displacement by the lever principle of the second arm. . Since the second piezo element 210 is fixed to the inclined frame 203, and the springs 214 and 215 support the second folder, the entire first folder is tilted by the second piezo element. The mirror 223 performs a panning operation.

The inclined frame 203 is connected to a connecting portion 203a.
Is fixed to the camera frame 200. A window 201 made of a transparent member is provided in the imaging direction, and the window 201 takes in external light.

(Explanation of Second Modification) FIG. 9 is an explanatory diagram of another modification using a bimorph. Bimorph,
In appearance, it has a structure in which two long plates are laminated like a bimetal, and each is a stack of thin laminated plates. Since the voltage applied to each laminated plate is reversed, the direction of expansion and contraction differs between the two plates. Therefore, like the bimetal, the bend is formed at the curvature with the extension extending outward. That is, here, the driving by a method other than the magnetic force is shown.

As in the first modification, the camera frame 25
An imaging unit 0 includes a lens 257, a CCD 256, and a substrate 255. Further, a first folder 261 and a second folder 263 are configured similarly to the first modification, and support the mirror 260. The first folder 261 is engaged with the tip of the first bimorph 265 at the arm tip 261a. Reference numeral 266 denotes a spring that supports the engagement part in an auxiliary manner.
The first bimorph 265 is fixed to a first angle 264 fixed to the second folder 263 at an end opposite to the engagement portion.

Further, the second bimorph 270 engaged with the second bimorph tip 270a at the arm tip 263a of the second folder 263 is connected to the second angle 2 at the other end 270b.
Fixed to 71. Then, the spring 271 supporting the second angle 271 and the second bimorph tip 270a is fixed on the inclined frame 252 fixed to the camera frame 250 at the fixing point 252a. Since the second folder is supported by the spring 272 on the other end 270b of the second bimorph, the mirror 260 can perform a tilt operation with the first bimorph 265 and a pan operation with the second bimorph 270. 251 is a window for taking in external light.

(Explanation of Third Modification) As described above, the moment applied to each axis differs between the pan motor and the tilt motor. This is because the pan motor only drives the mirror and the frame, whereas the tilt motor must drive the mirror with the pan motor and two folders.

Therefore, considering the optimum configuration, it is conceivable to make the outputs of the driving sources different in the pan direction and the tilt direction, for example, as shown in FIG. FIG.
Reference numeral 0 denotes an example in which two motors are prepared for tilt drive to achieve high output.

The first tilt motor 310 and the second tilt motor 320 are driven by the second cranks 311 and 321 respectively.
It is linked to the arms 312 and 322 on the lower surface of the folder.

The pan motor 300 mounted on the lower surface of the second folder drives the first folder 331 and the mirror 332 to swing in the same manner as in the example described above. In this example, the pan motor 300 and the tilt motors 310 and 320 use the same output motor.

Although not shown, it is also possible to design the output of the tilt motor to be large, for example, in addition to driving with two motors. For example, a large diameter results in a high output even with the same yoke length. Further, for example, if the pan motor is driven by the bimorph drive described above, the weight is reduced, so that the torque of the tilt motor can be reduced. That is, of the various driving methods, another driving method suitable for the pan direction and the tilt direction may be combined.

(Simple Description of Another Modification) FIG. 11
(A) and FIG. 11 (b) show two further modifications of the use of magnetism for the driving means. In FIG. 11A, the mirror 400
The arm 401 is provided in a folder 401 that holds the. On the side facing the arm 403, there is a projection provided with a magnet 405, and the coil 40
6 oscillate around the fulcrum 402 with the magnetomotive force of 6. At this time, the magnet 405 is displaced.
07 detects the change in the output voltage. In the case of the motor described above, the displacement (angular displacement) of the rotor is detected. In this case, the displacement is parallel to the Hall element 407.

In FIG. 11B, the folder 421 holding the mirror 420 has a recess in the center of the rear surface, and the pivot 423 is inserted into the recess, so that the folder 421 can move freely. A magnet 42 is provided near the four corners of the back of the folder 421.
5 is embedded. A coil 426 is provided immediately below the magnet 425, and the frame 421 is controlled by a magnetomotive force generated by energization, and moves around the pivot 423. Hall element 427 detects the magnetic flux of coil 425.

(Explanation of Mirror Shape) FIGS. 12 and 13 are illustrations in which the mirror shape is defined based on an optical study.

FIG. 12A is a projection view in the tilt direction. FIG. 12B is a projection view in the pan direction. In the pan direction, the mirror is orthogonal to the center optical axis of the lens in the reference state (origin position). For this reason, the projection of the lens imaging range is circular. When the mirror is tilted, it becomes elliptical. Also,
The tilt direction is not orthogonal, and is an ellipse even in the reference state (origin position).

That is, the projection range on the mirror is an elliptical area, and as shown in FIGS. 13A and 13B, four corners can be cut or an elliptical mirror can be used. Although additional processing cost is required as compared with a square mirror, reducing the weight of the mirror as much as possible can reduce the torque required for the drive means for tilting the mirror. As described above, it is significantly significant that the tilt-direction driving unit needs to drive both the pan-direction driving unit and the mirror, so that the pan-direction driving unit can be made light and small.

(Explanation of Keystone Correction of the Subject) As can be seen from FIG. 12A, the tilt direction is a mirror origin position at a position inclined by 45 ° from the center optical axis of the lens. P12, P
Reference numeral 22 denotes a boundary point of the imaging range. P0 is a point that does not change even if the inclination of the mirror changes.

Intersection point P between the center optical axis of the lens and the mirror
0, the optical midpoint L of the lens, P12, L, P0
Is equal to the angle formed by P22, L, and P0, but since the reference angle of the mirror is not 0 °, the angle of incidence on the mirror differs at the two points P12 and P22.

On the other hand, in the pan direction, as shown in FIG. 12B, since the reference angle of the mirror is 0 °, Q12,
The angle formed by L and Q0 is equal to the angle formed by Q22, L and Q0, but since the reference angle of the mirror is 0 °, the angle of incidence on the mirror is the same at Q12 and Q22. Due to this property, distortion differs between the pan direction and the tilt direction.

FIG. 14 illustrates the distortion that occurs when the mirror changes its direction with respect to the tilt direction. In the installation method in which the CCD is directed to information as a door phone as described above, A3, B3, A4, B4
It is assumed that the subject is located on the line of. When the mirror is tilted to the B1 and B2 lines (approximately 45 °), the imaging range is obtained in the direction of approximately 90 °. The imaging range is B3, B4. On the other hand, the mirror is A
When the line is inclined to the A1 and A2 lines, the imaging range is changed considerably downward. And the imaging range is A
3, A4.

As clearly shown in this figure, A
The length of B3 and B4 differs from the length of B3 and A4. 45 °
If the standard inclination is used, the top and bottom of the center are uniform, and if the lengths of B3 and B4 are set to 1, the lengths of A3 and A4 when the mirror is changed are larger than 1. It means that you are shooting the range that was done.

On the other hand, since the CCD of the imaging device converts the projected image into a signal with the same number of pixels, obtaining a large (enlarged) area with the same number of pixels means that
When a pixel signal obtained from the CCD is reproduced, a reduced image is obtained. Therefore, in order to always obtain an image of the same size without distortion regardless of the tilt of the mirror, enlargement processing according to the tilt of the mirror is performed. Since various known methods may be used for the enlargement / reduction, they are omitted here.

As described above, by appropriately performing enlargement processing in the pan direction and the tilt direction, an image in a square area can always be obtained. Also, since this algorithm can be achieved on software or hardware, it may be registered on the processing board 55,
The processing may be performed by software using an application or the like in the interfaced computer.

As described above, the direction of the reflecting surface of the mirror can be freely controlled, and the control may be performed by a dedicated control line, or the control of a general-purpose interface that interfaces with the camera. Alternatively, a command may be used. The details on the processing substrate are not described because they are not important to the gist of the present invention. However, as an example of using a general-purpose interface, a USB (Universal S
In an area bus, power supply is also possible. By taking advantage of this advantage, it can be used as a so-called mobile environment to carry outdoors.

In recent years, WI, which is the OS of a computer,
Since NDOWS (Microsoft) supports the USB interface as a standard interface, and can easily connect / disconnect devices, it can be easily constructed with a mobile phone as well as a conference system terminal at a personal home, a videophone, and the like.

The method proposed in the prior art is not suitable for use of a dry battery or the like because it requires a large amount of power. However, this method can reduce power consumption and can be carried around. High value as a pan-tilt camera to use.

A so-called door phone which is installed near the entrance of a house and is used in recent years is equipped with a camera for photographing a visitor. If the camera of the present invention is applied here, in addition to a tall adult, even if a small child visits, the problem of not being able to see the subject by pointing the camera to the optimal imaging position, such as a fisheye lens, It is preferable because it can be solved without large distortion, but if the camera interface is wireless, and it is battery-operated, it can be installed without putting a line outside when installing on the outer wall,
No damage to the walls.

Further, when considered as a camera for a portable terminal, it is preferable because the power consumption can be suppressed in the mobile environment described above.

[0069]

[Brief description of the drawings]

FIG. 1 is a schematic structural view showing the concept of a pan-tilt camera of the present application.

FIG. 2 is a side view of a main part of the pan-tilt camera of the present application.

FIG. 3 is a diagram of a motor structure for driving a mirror.

FIG. 4 is a diagram of a schematic magnetic circuit in a motor cross section.

FIG. 5 is a diagram of output of each Hall element in a pan direction and a tilt direction.

FIG. 6 is a diagram showing the relationship between the angle of the rotor of the permanent magnet and the output of the Hall element.

FIG. 7 is a drive circuit diagram of a motor.

FIG. 8 is a diagram of a first modification of the driving means.

FIG. 9 is a view of a second modification of the driving means.

FIG. 10 is a diagram of a third modification of the driving means.

FIG. 11 is a view of another modification of the driving means.

FIG. 12 is a conceptual diagram of a mirror imaging area.

FIG. 13 is a modified example of the mirror.

FIG. 14 is an explanatory diagram of an imaging region distortion.

FIG. 15 is a conventional diagram.

[Explanation of symbols]

 Reference Signs List 50 lens barrel 51 lens 52 CCD (imaging element) 53 imaging board 55 processing board 63 tilt motor 65 pan motor 70 mirror 71 first folder 75 second folder

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/225 H04N 5/225 E 7/18 7/18 HF Term (Reference) 5C022 AA01 AB51 AB62 AB42 AC42 AC51 AC74 5C054 AA01 AA05 CA04 CC06 CD06 CE08 HA18 HA22 HA25

Claims (22)

[Claims] An image pickup means for picking up an image of a subject, a lens for forming an image on the image pickup means, a mirror installed in front of the lens for changing an image pickup direction, and a driving means for changing the direction of the mirror. A camera comprising: a driving unit that generates a magnetic field according to a current, a permanent magnet opposed to the coil, and a displacement sensor that detects a relative displacement between the coil and the permanent magnet. Equipped camera 2. The camera according to claim 1, wherein said displacement sensor is a magnetic sensor near said permanent magnet for detecting magnetic flux density of a magnetic field. 3. The camera according to claim 2, wherein said camera includes current control means for performing feedback control of a current flowing through said coil based on an output signal from said magnetic sensor. 4. The camera according to claim 3, wherein said current control means is an analog control system capable of continuously controlling a current. 5. The camera according to claim 1, wherein said camera has a rotation axis perpendicular to a magnetic field generated by said permanent magnet from said coil. 6. The magnetic sensor according to claim 5, wherein the magnetic sensor is located at a boundary between the N pole and the S pole of the permanent magnet when the mirror is at the center of the imaging direction change range.
Camera 7. The camera according to claim 5, further comprising a drive transmitting means for transmitting a driving force of said rotating shaft to said mirror. 8. The camera according to claim 1, wherein the drive transmitting means includes a swinging member such as a lever and a cam provided on the rotating shaft and an engagement portion provided on a part of a frame supporting the mirror. 6. The camera according to claim 5, wherein the camera is in sliding contact. 9. An image pickup means for picking up an image of a subject, a lens for forming an image on the image pickup means, a mirror installed in front of the lens for changing the image pickup direction, and a driving means for changing the direction of the mirror for driving. Wherein the driving means includes a coil for generating a magnetic field in accordance with a current, a cylindrical permanent magnet magnetized in a diametric direction, and an axis for rotatably supporting the permanent magnet. Camera 10. The camera according to claim 9, wherein said camera comprises a displacement sensor for detecting a rotational displacement of said permanent magnet. 11. A feedback control of a current flowing through the coil based on a signal from the displacement sensor.
Camera 12. The camera according to claim 10, wherein said camera comprises a magnetic sensor, wherein said displacement sensor detects a magnetic flux density of a magnetic field. 13. An image pickup means for picking up an image of a subject, a lens for forming an image on the image pickup means, a mirror installed in front of the lens to change the image pickup direction, and a drive means for changing the direction of the mirror. Wherein the driving means includes a piezoelectric element. 14. The camera according to claim 13, wherein said piezoelectric element is a bimorph piezoelectric element. 15. The camera according to claim 1, wherein the camera is a mirror whose four corners are cut to form an octagon. 16. The camera according to claim 16, wherein the camera holds a mirror.
A first drive unit, which is the drive unit, is attached to one frame, a second folder that supports the first folder movably, and a second folder that is attached to a fixed frame that fixes the imaging unit. 15. The camera according to claim 1, wherein the first driving means drives the first folder. 17. The apparatus according to claim 1, wherein said second driving means has a higher torque output than said first driving means.
6 cameras. 18. The camera according to claim 16, wherein a plurality of said second driving means are provided. 19. An image pickup means for picking up an image of a subject, a lens for forming an image on the image pickup means, a mirror installed in front of the lens to change the image pickup direction, and a drive means for changing the direction of the mirror. Comprising a first casing for holding the image pickup means and a second casing for holding the mirror and drive means, which are interchangeable. 20. The apparatus according to claim 1, further comprising trapezoidal distortion correcting means for correcting trapezoidal distortion in which an imaging area generated when changing the imaging direction of the mirror is trapezoidal, based on the imaging direction. The stated camera 21. A mirror unit for a camera which is mounted in front of a lens of a camera for photographing a subject to move and change a photographing area, wherein a driving means for driving the mirror unit is adapted to drive the mirror unit in accordance with a current. A mirror unit for a camera, comprising a coil for generating a magnetic field, a permanent magnet arranged opposite to the coil, and a displacement sensor for detecting a relative displacement between the coil and the permanent magnet. 22. A mirror unit for a camera, which is mounted in front of a lens of a camera for photographing a subject and changes a photographing area, wherein the driving means for driving the mirror unit has a piezoelectric element provided with a piezoelectric element. unit