JPH0447695Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a rotary disk type shutter attached to a television camera.

[Conventional Example] Most of the image pickup tubes currently used in television cameras are storage type image pickup tubes. When light enters the imaging surface of this storage type image pickup tube, an electric charge is generated in that area, and this electric charge is converted into a video signal.

By the way, in the above image pickup tube, after the charge on the image pickup tube is lost by scanning one field, all the light incident on the image pickup surface is transferred to the next field until the next field is scanned. is stored as a field image. For this reason, when a television camera using a storage type image pickup tube takes a picture of an object moving at high speed, the object image moves on the imaging plane after one field is scanned and before the next field is scanned. , even the trajectory of the subject is converted into a video signal. When this video signal is reproduced, a flow occurs in the video, and the details of the image cannot be clearly seen.

One way to eliminate the above drawbacks is to attach a shutter on the optical axis of the TV camera lens, continuously turn off the high-speed shutter in synchronization with the TV camera's vertical drive signal, and take pictures using this shutter. Are known. By means of the above-mentioned shutter, an image is projected onto the imaging surface of the television camera for a very short period of time once per field. This short-time video is recorded on the imaging surface, and 1
Each field scan is converted into a video signal as a still image. Therefore, the image reproduced from this video signal on a monitor using a VTR, field memory, etc. is a continuous still image, with no image flow, and every detail is clear.

Conventionally, as the above-mentioned shutter for a television camera, there is a rotary disk type shutter having a structure shown in FIG. 6, for example. This is two disks 100a, 10
Two shutter holes 200a, 200a, 200b, 200b are formed at 180 degrees apart from each other in 0b, and these disks 100a, 100b are rotated on the same axis in mutually opposite directions in synchronization with a vertical drive signal of a television camera, Shutter hole 200
When a and 200b coincide on the optical axis of the television camera, the shutter is in an open state.

[Problems to be Solved by the Invention] In the conventional shutter for a television camera described above, two rotary disks in which shutter holes are formed are arranged on the same axis. Further, in order to rotate these rotating disks in opposite directions, rotating devices are provided at both ends of the axis.

For this reason, the shutter device has a large thickness in the axial direction, and for example, when this shutter device is interposed between a lens with a short focal length and a television camera, the distance between the lens and the television camera becomes large. This led to drawbacks such as the inability to focus the lens.

Further, the structure of rotating two rotary disks in opposite directions is relatively complicated and requires many gears, which increases the weight of the entire shutter device and is inconvenient for operation.

[Means for solving the problem] This invention consists of two rotating shafts arranged parallel to each other, and rotating shafts of the same diameter that are rotatably attached to each of these rotating shafts and whose ends overlap each other. a driven pulley coaxially fixed to each of these rotary discs and located on the same plane as each other, the axis of which is on the perpendicular bisector of a line connecting the centers of the driven pulleys and with the rotating shaft; A drive pulley arranged in parallel and on the same plane as each of the driven pulleys, a motor for rotating the drive pulley, and a motor and the drive pulley supported so as to be adjustable in position along the perpendicular bisector. and a belt wound between each of the driven pulleys and the driving pulley, and forming shutter holes in each of the rotary disks that coincide with each other at positions where the rotary disks overlap. It is characterized by becoming.

[Example] Figures 1 to 5 show an example of this invention.

In these figures, reference numeral 1 denotes a box-shaped case, and a fitting-type lid 2 is attached to the opening of the case 1 so as to close the opening. An opening 3 is formed in the center of the lid 2, and a lid-shaped camera mount 4 is attached thereto. Rotary disk shafts 5a and 5b are provided at a predetermined interval on the inner bottom surface of the case 1, and circular driven pulleys 6a and 6b of equal size are provided on each of the rotating disk shafts 5a and 5b. It is rotatably mounted via bearings 7,7. Circular rotary discs 8a and 8b of equal size are fixed to these pulleys 6a and 6b so that their ends overlap with each other. A synchronous motor 9 is attached to the external bottom of the case 1, and a rotating shaft 10 of the synchronous motor 9 passes through an opening 11 formed in the case 1 and projects vertically into the inside of the case 1. There is. A pulley 12 is fixed to the tip of the rotating shaft 9. Here, the rotating shaft 10 intersects with a perpendicular bisector of a line connecting the centers of each driven pulley 6a, 6b, and is arranged parallel to each rotating shaft 5a, 5b. An endless belt 13 is wound between each of the driven pulleys 6a, 6b and the driving pulley 12 so as not to be slidable. In addition, this belt 1
3 is preferably a T-belt with teeth formed on one side so that the pulleys 6a, 6b, and 12 do not rotate idly.

Each of the rotary disks 8a and 8b includes a rotary disk 8.
When rotating disks a and 8b, these rotary disks 8a,
Two circular shutter holes 14a, 14a, are arranged 180° apart so that they match each other at the overlapping positions of the shutter holes 8b, and match the opening 3 of the lid 2.
14b, 14b are formed.

The rotary disk shafts 5a and 5b are connected to the case 1 and the lid 2.
3, and both ends thereof are fixed by screws 15, 15, as shown in the sectional view taken along the line CC in FIG.

A motor frame 16 is fixed to the front surface of the synchronous motor 9, and elongated holes 17 (part of the tension adjustment mechanism) extending parallel to the perpendicular bisector are formed in the four corners of the motor frame 16. . Through these elongated holes 17, screws 18 (part of the tension adjustment mechanism) are respectively tightened into the bottom wall of the case 1, and by loosening each screw 18, the synchronous motor 9 is moved along the perpendicular bisector. The position can be adjusted along the As a result, belt 1
3 tension can be adjusted.

The camera mount 4 has screw holes 19, 19 formed at both ends thereof, and bolts 2 are inserted here.
0 and 20 are passing through. These two bolts 2
0 and 20 are spacers 21 and 2 that penetrate through the lid 2 and prevent the lid 2 and the case 1 from being bent.
1 and the case 1, and is fixed at the bottom of the case 1 by nuts 22, 22. The camera mount 4 has an opening 23 formed at a position that matches the opening 3 of the lid 2, and a camera connecting portion 24 is formed in this opening 23.
A camera connecting portion 24 is attached to this opening 23. Further, an opening 25 is formed on the bottom surface of the case 1 at a position that matches the opening 23 and the opening 3, and a lens connecting portion 26 for connecting a camera lens 27 is provided to the opening 25. There is.

An opening 28 is formed at the end of the lid 2, which matches another shutter hole 14a when the openings 3, 23, 25 and the shutter hole 14a of the rotary disc 8a match. A light emitting unit 29 is attached to monitor the rotational phase of the rotational axis 8a. Furthermore, an opening 30 is formed in the case 1 at a position facing the light emitting section 29, and a light receiving section 31 that receives light from the light emitting section 29 is attached to the external bottom surface of the case 1 so as to cover this opening 30. It is being

The mounting structure for the case 1 and the lid 2 is as shown in the sectional view taken along the line A-A in Figure 2.The upper end of the internal side surface of the case 1 is cut out in a step-like manner, and the lid 2 is fitted therein and secured with screws. It is.

Next, the operation of the rotary disc type shutter having the above structure will be explained.

First, an alternating current is supplied to the synchronous motor 9 from a power supply device (not shown), which will be described later, to rotate the rotary disk 10 of the synchronous motor 9. This rotation of the rotating shaft 10 is caused by the pulley 12
is transmitted to the belt 13, causing the pulleys 6a and 6b to rotate in the same direction and at the same speed. As a result, the rotary disks 8a and 8b fixed to the pulleys 6a and 6b rotate in the same direction and at the same speed, and each time these rotary disks 8a and 8b rotate 180 degrees, the shutter holes 14a and 14b open. Openings 3, 2
They match each other at the positions that match 3 and 25. At this time, the other shutter hole 14a of the rotary disk 8a
is located between the light emitting section 29 and the light receiving section 31 , and the continuous light emitted by the light emitting section 29 enters the light receiving section 31 . A light receiving element is provided inside the light receiving section 31, and incident light is converted into an electrical signal, and opening/closing of the shutter is detected as an electrical signal based on this signal. This electrical signal is compared within the power supply with the vertical drive signal of the television camera. If the shutter opening/closing and the vertical drive signal are out of phase, the phase of the alternating current supplied to the synchronous motor is adjusted within the power supply to ensure that the shutter opening/closing and the field scanning of the television camera are always synchronized. let

On the other hand, the light from the lens 27 attached to the lens connecting portion 26 is transmitted through the shutter holes 14a, 14.
Only at the moment when b matches, the light passes through this shutter device and enters the television camera attached to the camera connection section 24. As a result, an image is projected onto the image pickup tube of the television camera for a very short period of time for each field, and this image is recorded on the image pickup tube. Since this short-time video is converted into a one-field video signal, even when an object moving at high speed is photographed, the one-field image that is reproduced is a clear still image with no flow.

[Effects of the invention] The rotary disk type shutter for television cameras of this invention provides the following excellent effects.

Compared to conventional shutters that have two rotary discs arranged on the same axis, the entire shutter device can be made thinner, so the distance between the TV camera and the lens is smaller, and even when a short focal length lens is attached, the lens can be easily moved. Does not interfere with focusing.

The shaft center of the rotary disk and the shaft center of the motor are arranged in a triangular shape divided into two halves, and they are linked by a belt, so the distance between the shutter opening and the motor can be maintained regardless of the diameter of the rotary disk. can be set freely and prevents interference between the motor and lens even when a thick lens is attached.

The vibrations generated by the motor are absorbed by the belt and are less likely to be transmitted to the rotary disk, resulting in low noise and excellent quietness.The rotary disk is less prone to uneven rotation due to vibration, improving the accuracy of opening and closing the shutter due to uneven rotation. Deterioration can be prevented.

Because it uses a belt, it is lighter than conventional shutters that often use relatively heavy gears, and it is also less likely to malfunction if dust or other particles get into the shutter.

When assembling the device, the tension adjustment mechanism moves the motor and drive pulley toward the driven pulley, and after winding the tension belt between each pulley, the tension adjustment mechanism moves the motor and drive pulley away from the driven pulley. By moving the timing belt in the direction of separation, the tension of the timing belt can be set to an appropriate value, so the belt can be easily attached and detached, and the apparatus can be assembled quickly. Further, since the tension can be adjusted after assembly, the arrangement accuracy and processing accuracy of the driving pulley and each driven pulley can be relatively low, and the manufacturing cost is accordingly low.

When in use, a rotary disk is placed on both sides of the TV camera, and a motor is placed directly above (or directly below) the TV camera, so the weight is evenly distributed on the left and right sides of the optical axis, and the entire shutter system is The center of gravity is located near the optical axis, the weight balance around the optical axis is good, and the light weight combined with excellent operability. This is an important effect when considering the mobility and operability required for television cameras.

[Brief explanation of the drawing]

1 to 5 are diagrams showing an embodiment of this invention. Fig. 1 is a plan view of a rotary shutter for a television camera, Fig. 2 is a sectional view taken along the line A-A in Fig. 1, Fig. 3 is a sectional view taken along the line C-C, and Fig. 4 is a sectional view taken along the line C-D.
A line sectional view and FIG. 5 are side views schematically showing the use of this invention. Further, FIG. 6 is a diagram showing a conventional example. 5a, 5b...rotating shaft, 6a, 6b...driven pulley, 8a, 8b... rotating disk, 10... rotating shaft,
12... Drive pulley, 13... Timing belt, 14a, 14b... Shutter hole, 16...
Motor frame, 17... Long hole (part of the tension adjustment mechanism), 18... Screw (part of the tension adjustment mechanism).

Claims (1)

[Claims for Utility Model Registration] Two rotating shafts arranged parallel to each other; a rotating disk having the same diameter and rotatably attached to each of these rotating shafts so that the ends overlap each other; Driven pulleys that are coaxially fixed to each of the rotary disks and located on the same plane as each other, and their axes are arranged on the perpendicular bisector of the line connecting the centers of each of the driven pulleys and parallel to the rotation axis. a drive pulley disposed on the same plane as each of the driven pulleys, a motor for rotating the drive pulley, and a tension adjuster that supports the motor and the drive pulley so that their positions can be adjusted along the perpendicular bisector. a mechanism, and a belt wound between each of the driven pulleys and the drive pulley, and each of the rotary disks is provided with shutter holes that coincide with each other at positions where the rotary disks overlap. Features a rotary shutter for television cameras.