JPS62245892A - Filter loading unloading mechanism - Google Patents

Abstract

PURPOSE:To reduce the number of components, to decrease the manufacture cost of a camera and to attain miniaturization and light weight of the camera by integrating an automatic aperture, a filter and a filter loading/unloading mechanism. CONSTITUTION:A meter 1 driving an aperture blade 19 in response to the brightness of a object is fixed to a base/plate 2 and a filter frame 3 bonded with a color temperature correction filter 20 is fitted to a plunger 5 of an electromagent device by a screw 11. The plunger 5 is fixed to the base plate 2 to the plunger shaft 12 via a yoke 4. In applying power to a coil 13 wound on the plunger shaft 21, a magentic flux is formed in a magnetic circuit comprising the shaft 12, the yoke base 4a, a yoke circular-ark 4c, the plunger 5 and the shaft 12, the plunger 5 is driven clockwise where the area of the circlar-arc 5b of the plunger 5 is overlapped with the circlar-arc 4c of the yoke 4 is increased, the arm 5a is attracted by an iron core of a permanent magnet of the electromagnet 6 and the filter 20 is loaded into the pickup optical system.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a mechanism for moving a color temperature correction filter into and out of a photographing optical path in a video camera or the like.

Conventional technology When photographing with a video camera, in order to improve color reproducibility, it is necessary to insert or remove a color temperature correction filter from the photographing optical system depending on the external lighting conditions of the subject. For this reason, video cameras are equipped with a color temperature correction filter loading/unloading mechanism, but the conventional filter loading/unloading mechanism is a unit separate from the automatic aperture mechanism unit of the photographic lens, and each unit is independent from the other. It had a mounting part for the camera. As a result, the number of parts surrounding the photographing lens increases, and the diaphragm drive mechanism, filter inlet/outlet mechanism, and structure each require a considerable volume, which hinders the compactness and weight ratio of the video camera.

C6 Problems to be Solved by the Invention The present invention combines both the automatic aperture mechanism and the color temperature correction filter insertion/extraction mechanism of a video camera into a single unit,
The aim is to make video cameras smaller and lighter.

24 Means for Solving Problems The filter frame is rotatably attached to the structural board (base plate) of the automatic diaphragm device, the filter frame driving device is also attached to the substrate, and the automatic diaphragm device and the filter loading/unloading mechanism are connected to the base plate. integrated as a medium.

The automatic diaphragm device is attached to the camera by a base. In the present invention, the filter inlet/outlet mechanism is also attached to the main plate, so there is no need for a separate base plate for the filter inlet/outlet mechanism, and there is no need for any members to attach it to the camera, reducing the number of parts. The overall structural volume is also reduced, contributing to the miniaturization of cameras.

Embodiment FIG. 1 shows an embodiment of the present invention. Reference numeral 1 denotes a meter that responds to the brightness of the subject and drives the aperture blades 19 (only one blade is shown in the figure). A meter 1 is fixed to a base plate 2. 3 is a filter frame to which a color temperature correction filter 20 is glued. This filter frame 3 is attached with a screw 11 to a plunger 5 of an electromagnetic device that moves the filter 20 into and out of the photographic optical system. The figure shows the filter 20 inserted into the photographic optical system. The plunger 5 is rotatably held by a plunger shaft 12, and the plunger shaft 12 is mounted on a yoke 4 and has a coil 13 wound thereon, as shown in FIG. The yoke 4 is fixed to the base plate 2 with screws 10. As shown in FIG. 1, the plunger 5 consists of a straight arm 5a to which the filter 20 is fixed, and a quarter-half circular arc part 5b extending from the rotating end of this arm, and has a yoke. 4 is a base 4 that comes into contact with the main plate 2, as shown in FIG.
a, a bent-up portion 4b at the end opposite to where the plunger shaft 12 at the base is planted, and a bent-up portion 4
It consists of a quarter-half circular arc portion 4.0 extending from b into a plane parallel to the base 4a (horizontal view in the figure), and as shown in FIG.
It is parallel to 5b on the outside of 5b at the same height as . A spring 8 is stretched between the end of the arm of the plunger 5 opposite to the filter attachment end and a bottle 9 set up on the main plate 2, and this spring causes the plunger 5 to move as shown in FIG. It is biased counterclockwise. Reference numeral 6 denotes a self-holding type electromagnetic device in which a coil is wound around the iron core of a permanent magnet, and is attached by screws 7 to a spacer 25 established on the base plate 1 shown in FIG. The magnet is at the same height as the plunger 5, and when the plunger 5 is brought to the position shown in Figure 1, the permanent magnet of the iron core attracts the arm 5a of the plunger 5, and the force of the spring 8 The plunger 5 is held in the position shown in FIG. In this state, when the colorimeter of the video camera determines that a filter is not required, a pulse current flows through the winding of the electromagnet device 6 in the direction of canceling the magnetic force of the permanent magnet of the iron core, temporarily turning off the electromagnet device. Weaken the plunger retention force. Therefore, the plunger 5 is rotated approximately 90° counterclockwise by the force of the spring 8, and
The part a hits the stop 22 erected on the main plate 1 and stops at that position. The position of the filter 20 at this time is the position where the filter escapes from the photographing optical system. In this state, when the video camera's colorimeter determines that a filter is necessary, the coil 13 wound around the plunger shaft 12
is energized. The direction of the current at this time may be either direction. When the coil 13 is energized, the plunger shaft 12. Yoke base 4a, yoke arc portion 4C, plunger 5. The plunger 3 rotates in the direction passing through the plunger shaft 12, that is, clockwise, and the arm portion 5a comes into contact with the magnetic pole of the electromagnet device 6.

Even if the current to the coil 12 is cut off in this state (FIG. 1), the plunger 5 is attracted to the iron core of the permanent magnet of the electromagnetic device 6, so that the state shown in FIG. 1 is maintained.

FIG. 3 shows another embodiment of the invention. In this figure as well, parts corresponding to those in the embodiment shown in FIG. 1 are given the same numbers. The filter frame 3 is rotatably attached to the main plate 2 by a support shaft 14, and a permanent magnet 1 is attached to the end of the filter frame 3 opposite to the end to which the filter 20 is glued.
5 is attached with both poles facing the rotation direction of the filter frame 3. 21a and 21b are soft iron cores, and the soft iron cores are wound with an excitation coil 16. 17 is the power supply and 1
8 is a relay switch. In operation, when this relay switch 18 is in the position shown in FIG.
The side closer to the pole becomes the north pole, which repels the north pole of the permanent magnet 15 and inserts the filter frame 3 into the photographing optical path. At this time, the side of the other soft iron core 21a that is closer to the S pole of the permanent magnet 15 becomes the N pole, facilitating the movement of the filter frame 3. Filter frame 3
Even if the power to the excitation coil 16 is stopped when the magnet reaches a predetermined position, the S pole of the permanent magnet 15 is attracted to the soft iron core 21a, and residual magnetic force remains and the filter frame 3 is held in the position shown in the figure. be done. Next, when taking the filter frame 13 out of the optical path, by switching the relay switch 18, the direction of the current in the coil 16 will be reversed to that described above, and the direction of the current in the coil 16 will be reversed to the S pole, S pole,
Due to the attraction and repulsion of the N pole, the filter frame 3 rotates counterclockwise and exits from the photographing optical path. Furthermore, here as well, the filter frame 3 is held at a position out of the photographing optical path by the residual magnetic force in the iron core 21b due to attraction between the N pole of the permanent magnet 15 and the iron core 21b.

Effects The filter drive mechanism of the present invention has the above-described configuration, and the filter frame is rotatably mounted on the structural board of the automatic diaphragm, and the filter frame drive device is also mounted on the same board, so that it can be used as an automatic diaphragm. Since the filter and the filter loading/unloading mechanism are integrated, the structure for attaching the automatic aperture device and the filter loading/unloading device to the camera is standardized, reducing the number of parts and the amount of assembly work, which reduces camera manufacturing costs. It becomes easier to make the camera smaller and lighter, and it becomes easier to share the automatic aperture mechanism and filter insertion/extraction mechanism with other models.

[Brief explanation of drawings]

FIG. 1 is a plan view of one embodiment of the present invention, FIG. 2 is a perspective view of essential parts of the same embodiment, and FIG. 3 is a plan view of another embodiment of the present invention. 1... Aperture blade drive meter, 2... Base plate, 3...
- Filter frame, 12.14... Support shaft of filter frame, 4... Yoke, 5... Plunger, 6... Self-holding type electromagnetic device. Agent: Hiroshi Agata, Patent Attorney Figure 1, Figure 3Ii! ! 3

Claims (1)

[Claims] A filter characterized in that a filter frame is rotatably attached to a structural substrate of an automatic diaphragm device of a photographic lens, a filter frame drive device is fixed to the substrate, and the filter frame is integrated with the automatic diaphragm device via the substrate. Entry/exit mechanism.