JPH08116478A - Filter changeover mechanism - Google Patents

Abstract

PURPOSE: To prevent deterioration in the optical performance of a camera due to deposition of abrasion powder onto a filter or an optical element by turning a turning body having plural filters not in contact with the changeover means in the filter changeover mechanism for a television camera. CONSTITUTION: Four magnets 16A to 16D are provided to a turning body 5 having four filters 6A to 6D. A 2nd magnet 17 is provided to a position opposite to the magnet 16A when the desired filter 6A is positioned on an optical axis X. The poles S, N are located at this position so that the 1st and 2nd magnets 16A, 17 are attracted with each other. Thus. the filter 6A is easily located on the optical axis C and a click sensation in the case of positioning is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter switching mechanism, and more particularly to a filter switching mechanism for an image pickup device such as a television camera capable of rotating and switching a plurality of filters.

[0002]

2. Description of the Related Art In a conventional television camera for image pickup, a lens mount 4 is provided on a television camera body 2 as shown in FIG. 2, and a lens 3 such as a zoom lens is attached to the lens mount 4. . The light that has passed through the lens 3 and enters the television camera main body 2 receives the ND filter or the C provided in the filter switching mechanism 1.
One of a plurality of filters such as a C (color conversion) filter arranged on the optical axis X (optical path) is transmitted, and further enters the color separation prism 11, and RGB 3
CCD12R, which is separated into colors and detects each color
It is configured to be detected by 12G and 12B. Next, details of the filter switching mechanism will be described.

FIG. 3 is a diagram showing details of the filter switching mechanism. As shown in FIG. 3, the filter switching mechanism 1 includes four filters 6 on a concentric circle centered on the rotation axis O of the rotating body 5.
A to 6D are provided, and four concave portions 13A to 13D are provided on the outer periphery of the rotating body 5 at equal intervals. Furthermore, when the desired filter 6A among the four filters 6A to 6D is positioned on the optical axis X, the desired filter 6A is engaged with the recess 13A.
A leaf spring 15 for urging the rotating body 5 in the direction of the rotation axis O is provided in the rotating body mounting body 20 so that A is positioned on the optical axis X. A gear 7 is provided on the rotary shaft O of the rotator 5, and the gear 7 meshes with an idle gear 8 shown in FIG. 2. Further, the idle gear 8 is provided on a switching knob 9 protruding to the outside of the television camera body 2. It meshes with the gear 10 that was set.

When switching the filter, the switching knob 9 is rotated to rotate the gear 10, and thereby the idle gear 8 and the gear 7 are rotated to rotate the rotating body 5. Here, since the leaf spring 15 is biased in the direction of the rotation axis O of the rotating body 5, a certain amount of force is required when the leaf spring 15 is disengaged from the recesses 13A to 13D, and a desired filter is cut. When the switching knob 9 is changed, the concave portions 13A to 13D are forcibly engaged, so that a click feeling can be obtained while the switching knob 9 is being rotated, and it can be recognized by the feel of the hand that the filter has been changed. It is like this.

[0005]

However, in the above-described filter switching mechanism, the rotor 5 is rotated while the leaf spring 15 is always in contact with the rotor 5 to rotate the filter 6A.
6D is switched, and since the leaf spring 15 is biased in the direction of the rotation axis O, when the rotor 5 is rotated, friction between the leaf spring 15 and the rotor 5 causes the rotor 5 to rotate.
There is a risk that the outer circumference of the camera will be worn, and the abrasion powder generated by this abrasion will adhere to the filters 6A to 6D and the optical elements in the camera body 2 to deteriorate the optical performance of the camera. Also,
There is a possibility that the leaf spring 15 may be bent or that the desired filters 6A to 6D may not be accurately positioned on the optical path X.

In view of the above circumstances, the present invention provides a filter switching mechanism in which abrasion powder due to abrasion of a rotating body does not adhere to a filter, an optical element of a camera, and the like, and further, a desired filter is always positioned on an optical path. It is an object of the present invention to provide a filter switching mechanism that can be used.

[0007]

A filter switching mechanism according to the present invention comprises a plurality of filters arranged on a circumference of a rotating body that rotates about a rotating shaft as a center. A filter switching mechanism having a switching means for rotating the rotating body so as to position a desired filter of the filters on a predetermined optical path and switching the plurality of filters on the optical path, wherein the switching means is , Means for switching the filter in a non-contact state with the rotating body.

Further, in the filter switching mechanism according to the present invention, it is preferable that the switching means is a means for switching the filters by magnetic force so that the desired filter is positioned on the optical path.

Further, in the filter switching mechanism according to the present invention, the switching means is arranged such that the S pole and the N pole are arranged substantially along the circumference of the rotating body centered on the rotation axis.
When at least one first magnet portion provided on the circumference and the desired filter are positioned on the predetermined optical path, the S pole of the first magnet portion has an N pole.
The pole may be composed of at least one second magnet portion fixed in a non-contact state in the vicinity of the first magnet portion such that the south pole faces the north pole of the first magnet portion. More preferable.

[0010]

In the filter switching mechanism according to the present invention, the switching means rotates the rotating body in a non-contact state with the rotating body to switch the filters, so that the rotating body and the switching means are in contact with each other. It is possible to switch the filter without rotating and without causing the rotating body to wear. Therefore, abrasion powder is prevented from being generated and adhering to the optical elements of the camera to deteriorate the performance of the camera.

A magnet such as an electromagnet or a permanent magnet can generate a magnetic force semipermanently. Therefore, by switching the filter by magnetic force so that the desired filter is positioned on the optical path,
The positioning function of the rotating body is semi-permanently maintained. Further, by switching the filter by magnetic force, it becomes possible to easily and inexpensively configure the filter switching mechanism.

Further, the switching means is provided on at least one first pole provided on the circumference so that the S pole and the N pole are arranged substantially along the circumference centered on the rotation axis of the rotating body. When the magnet unit and the desired filter are positioned on the predetermined optical path, the S pole and the N pole of the first magnet unit are
Of at least one second magnet part fixed in the vicinity of the first magnet part so that the south pole faces the north pole of the magnet part of the filter. When positioned, the first and second magnet parts attract each other, so that the filter is positioned on a predetermined optical path. On the other hand, when the rotating body is slightly rotated to switch the filter, the first and second magnet portions attracting each other change from attracting each other to repelling each other. Even away from the repulsive position, the magnetic forces do not act on each other. Furthermore, when the rotator is rotated and another desired filter is positioned near the optical path, the two magnet parts approach each other while repelling each other. Further, when the rotator is rotated, the two magnet parts are The repulsive state is changed to the mutually repulsive state, and the filter is positioned at the mutually reciprocal position. Therefore, when the desired filter is positioned on the optical path by rotating the rotating body, a click feeling when the leaf spring of the conventional filter switching mechanism engages with the recess of the rotating body is obtained, and the rotating means is rotated. When operated by hand, it is possible to easily feel by hand whether the desired filter is positioned in the optical path.Furthermore, when the rotating body is rotated when switching to another filter, the leaf spring will be released from the recess. The feeling of being disengaged can be obtained, and the filter can be switched in the same manner as when the filter is switched using the conventional leaf spring.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing details of a filter switching mechanism according to the present invention. As shown in FIG. 1, the filter switching mechanism 1 according to the embodiment of the present invention is provided in the TV camera body 2 shown in FIG. 2 described above, and the rotary shaft O is centered on the rotary body mounting plate 20. The rotating body 5 is rotatably provided. The rotating body 5 is provided with four types of filters 6A to 6D, the rotating shaft O thereof is provided with a gear 7, and four magnets are provided in the vicinity of the outer periphery of the rotating body 5.
16A to 16D are attached at equal intervals. The four magnets 16A to 16D are provided so that the S pole and the N pole extend substantially along the outer circumference thereof, and each magnet 16A
The 16-pole S-pole and the N-pole are provided so as to have the same phase. Further, the rotating body mounting plate 20 is provided with a second magnet 17, and the second magnet 17 includes four magnets 16A to 16A.
4 magnets 16A-16 so as not to contact any of 16D
When a desired filter (filter 6A in FIG. 1) of the four filters 6A to 6D, which is provided outside the concentric circle in which D is provided, is positioned on the optical axis X, The first magnet (the magnet 16A in FIG. 1) is provided in a position where it does not contact but is attracted.

On the other hand, the gear 7 meshes with the idle gear 8 similarly to the conventional filter switching mechanism described above, and the idle gear 8 meshes with the gear 10 provided on the switching knob 9. The operation of this embodiment will be described below.

Filters 6A to 6D provided on the rotary plate 5
When switching to a desired filter, the switching knob 9 is manually rotated. When the switching knob 9 is rotated in the direction of arrow A, the gear 10 provided on the switching knob 9 is rotated, whereby the idle gear 8 and the gear 7 provided on the rotating body 5 are rotated, and the rotating body 5 is rotated by the arrow. Rotate in the B direction. When the rotator 5 rotates and the desired filter (in this embodiment, the filter 6A) is positioned near the optical axis X, the magnet 16A is positioned near the second magnet 17. At this time, the south pole of the magnet 16A and the south pole of the second magnet 17 face each other. In such a state, the two magnets repel each other, so that the hand rotating the switching knob 9 feels repulsive to each other.

When the rotation is further continued, the S pole of the first magnet 16A and the N pole of the second magnet 17 face each other, and the N pole of the first magnet and the S pole of the second magnet mutually face each other. The rotating body 5 is positioned so as to face each other. In such a state, the two magnets 16A and 17 attract each other, so that the rotating body 5 is positioned at this position. At this time, the desired filter 6A is positioned on the optical axis X. Also, the feel of the hands that rotate the switching knobs is such that they repel each other and suddenly attract each other to be locked in that position, similar to the conventional filter switching mechanism that switches filters using leaf springs. Further, since the click feeling when the leaf spring is engaged with the concave portion of the rotating body is also obtained, it is understood that the desired filter 6A is positioned on the optical axis X by the feel of the hand.

Further, as described above, the filter 6A has the optical axis X.
When the filter is to be switched to another filter after being positioned above, the switching knob 9 is slightly rotated so that the N pole of the magnet 16A and the N pole of the magnet 17 are positioned to face each other. Therefore, the feel of the hands that rotate the switching knobs 9 is such that the feel of pulling each other suddenly repels each other and advances the rotation, and the fact that the positioned filter 6A is separated from the optical axis X depends on the feel of the hands. You will understand.

Further, since the first magnet 16A and the second magnet 17 are not in contact with each other, the leaf spring and the leaf spring are contacted with each other so that the leaf spring and the rotor are brought into contact with each other to switch the filter. The generation of abrasion powder due to abrasion with the rotating body is eliminated. Therefore, the abrasion powder is prevented from adhering to the filter or the optical elements in the camera body and losing the performance of the camera.

Further, it is possible to prevent the positioning accuracy of the filter from being lost due to the flat spring denting as in the conventional filter switching mechanism, and it is possible to maintain the positioning accuracy of the filter semipermanently.

Next, a second embodiment of the filter switching mechanism according to the present invention will be described.

FIG. 4 is a diagram showing a second embodiment of the filter switching mechanism according to the present invention. As shown in FIG. 4, in the second embodiment of the filter switching mechanism according to the present invention, four filters 6A to 6D and 4 are provided on the rotating body 5 which rotates about the rotation axis O as in the first embodiment of the present invention. First magnet 16A
~ 16D is provided. A plurality of electromagnets 21 are provided on the rotating body mounting plate 20 in a non-contact state with the outer periphery of the rotating body 5. The electromagnet 21 is controlled by the principle of a linear motor to rotate the rotating body 5. Less than,
The operation of the second embodiment of the filter switching mechanism according to the present invention will be described. Here, the electromagnet 21 near the magnet 16A is
Only the control of the other magnets 16B, 16C, 16D
Since the control of the electromagnet in the vicinity of is the same as the control of the electromagnet in the vicinity of the magnet 16A, detailed description will be omitted.

In the state shown in FIG. 4, the magnet 16A faces the electromagnet 21A. In this state, the electromagnet 21
A is in a non-energized state, and electromagnet 21 adjacent to electromagnet 21A
The sides of the B and the electromagnet 21Z facing the rotating body 5 are controlled so as to have an N pole and an S pole, respectively. Therefore, the magnet 16A attracts the electromagnets 21B and 21Z to each other, the rotating body 5 stands still at the position shown in FIG. 4, and the filter 6A moves toward the optical axis X.
It is positioned on top.

When the rotor 5 is rotated in the direction of the arrow B to switch the filters, the electromagnet 21Z is first controlled to have the N pole. Here, since the electromagnet 21B has the N pole, the N pole of the magnet 16A and the electromagnet 21Z repel each other, and the rotating body 5 starts rotating in the arrow B direction. Next, the electromagnet 21A is N
Each of the electromagnets 21A and 21A has a pole so that the electromagnet 21C becomes an N pole.
Control C and stop the current to the electromagnet 21B. As a result, the rotating body 5 further rotates in the arrow B direction. Then
The electromagnet 21B and the electromagnet 21D are set to the N pole to stop the current to the electromagnet 21C. This control is sequentially performed from the electromagnet 21A to the electromagnet 21.
When it is repeated up to K, the rotating body 5 rotates in the direction of arrow B, and the filter 6D is positioned near the optical axis X.

Here, the control of the electromagnet 21 for stopping the filter 6D on the optical axis X will be described. When the rotor 5 is rotated to bring the magnet 16A onto the electromagnet 21I, the electromagnet 21K is controlled so that the N pole becomes the N pole and the electromagnet 21I becomes the S pole, and the energization of the electromagnet 21J is blocked. As a result, the magnet 16A attracts the electromagnets 21I and 21K to each other and stands still at a position facing the electromagnet 21J, whereby the filter 6D is positioned on the optical axis X. The above control is performed for the electromagnets 21 other than the electromagnets 21A to 21Z, and the desired filter is positioned on the optical axis X.

In the second embodiment of the present invention described above, a plurality of electromagnets 21 are provided, but the number of electromagnets 21 need not be so large.

In the second embodiment of the present invention described above, as means for detecting that the magnet 16A has rotated near the electromagnet 21I, a reflecting plate is provided on the surface of each of the magnets 16A to 16D, and a desired plate is provided. A photodetector such as a photointerpreter is provided so as to face the magnets 16A to 16D when the filter is positioned on the optical axis X.
Accordingly, it is sufficient to detect that each of the magnets 16A to 16D is rotated to a position where the filter can be positioned on the optical axis X.

In the above embodiment, the rotating body is rotated by the magnet in the non-contact state with the switching means, but the present invention is not limited to this, and the switching means and the rotating body are in the non-contact state. Any means may be used as long as it switches the filters with.

Further, in the first embodiment, the first
The magnet is used as a single body, and the S pole and the N pole of this magnet are arranged to extend on the circumference around the rotation axis O.
Two first magnets are provided, and the S pole of one magnet and the N pole of the other magnet are made to face each other, and the S pole and the N pole which face each other are on a circumference centered on the rotation axis. The first magnet may be provided so that the first magnet is arranged at.

A plurality of first magnets are provided, and the S of each magnet is
The poles and the N poles are alternately arranged on the circumference, and a plurality of second magnets are provided so that the S poles and the N poles of each magnet alternately face the first magnets. It's okay. As a result, when the rotating body is rotated, a click feeling is obtained every time the S-pole and the N-pole are alternately arranged, and the rotating body is rotated little by little to switch the filters.

Further, in the first embodiment, the first
A magnetized body such as an iron piece may be provided in the vicinity of the outer periphery of the rotating body instead of the magnet, and the filter may be positioned on the optical path by using the attractive force between the magnetized body and the second magnet. It is a thing. On the contrary, instead of the second magnetic body, a magnetized body such as an iron piece is provided on the rotating body mounting plate, and the filter is positioned on the optical path by using the attractive force between the magnetized body and the first magnet. You may do it.

Further, in the above embodiment, RGB3
Each color is detected by the three CCDs 12R, 12G, 12B, but it is not limited to this, and only one CCD is used and RGB filters are provided in a checkered pattern on the photosensitive surface of this CCD. It is also possible to dispose one of them and detect the light of three colors of RGB by one CCD, and further provide two CCDs and one C.
G for RGB by CD, R and G by other CCD
May be detected.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of a filter switching mechanism according to the present invention.

FIG. 2 is a partial sectional view of a television camera including a filter switching mechanism.

FIG. 3 is a diagram showing a conventional filter switching mechanism.

FIG. 4 is a diagram showing a second embodiment of the filter switching mechanism according to the present invention.

[Explanation of symbols]

 1 Filter switching mechanism 2 TV camera body 3 Lens 4 Mount 5 Rotating body 6A-6D Filter 7, 10 Gear 8 Idle gear 9 Switching knob 11 Color separation prism 12R, 12G, 12B CCD 13A-13D Recess 15 Leaf spring 16A-16D No. 1 magnet 17 2nd magnet 20 Rotating body mounting plate 21, 21A-21K, 21Z Electromagnet

Claims (3)

[Claims] 1. A rotating body that rotates about a rotation axis,
On the optical path, a plurality of filters are arranged on a circumference centered on the rotation axis, and the rotating body is rotated so that a desired filter among the plurality of filters is positioned on a predetermined optical path. 2. A filter switching mechanism having switching means for switching the plurality of filters, wherein the switching means is means for switching the filters in a non-contact state with the rotating body. 2. The filter switching mechanism according to claim 1, wherein the switching means is means for switching the filters by magnetic force so that the desired filter is positioned on the optical path. . 3. The switching means is arranged so as to extend along a circumference of a circle about the rotation axis of the rotary body.
When at least one first magnet portion provided on the circumference such that the pole and the N pole are arranged and the desired filter are located on the predetermined optical path, At least one is fixed in the vicinity of the first magnet portion in a non-contact state so that the north pole is opposed to the south pole of the first magnet portion and the south pole is opposed to the north pole of the first magnet portion. The filter switching mechanism according to claim 1 or 2, wherein the filter switching mechanism comprises two second magnet portions.