JPH02842Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a focusing device for an image pickup tube used in a television camera or the like.

(Constitution of Conventional Example and Its Problems) In general, a focusing device for an image pickup tube holds an image pickup tube and applies a focusing magnetic field to an electron beam emitted inside the image pickup tube.

As a conventional example of such a focusing device for an image pickup tube,
FIG. 1 shows an example in which an electrostatic deflection electromagnetic focusing type image pickup tube is used. In FIG. 1, a focusing coil 2 is wound around the outer periphery of a cylindrical coil bobbin 1 made of a resin molded body.
is inserted. At this time, the target ring 6 protruding from the outer peripheral surface near the face plate 5 on the front surface of the imaging tube 3 comes into contact with the stepped portion 4 on the front surface of the coil bobbin 1, thereby positioning the imaging tube 3 in the axial direction. The axis of the imaging tube 3 is aligned by a spring tongue piece 7 that protrudes rearward from around the opening on the rear surface of the coil bobbin 1. Then, the outer periphery of the spring tongue piece 7 is tightened by a metal tightening band 8, and the imaging tube 3 is held on the coil bobbin 1. In addition, 9 is a screw for tightening the tightening band 8, and 10 is a magnetic shielding material made of permalloy material for covering the outer periphery of the focusing coil 2 and shielding an external magnetic field.

However, in such a conventional image pickup tube focusing device, when the tightening band 8 is tightened with the screw 9 to hold the image pickup tube 3 inserted into the coil bobbin 1, the tightening force is applied to the spring tongue piece 7.
The rear part of the image pickup tube 3 moves about 0.2 mm to 0.5 mm in the direction shown by arrow a, and the image pickup tube 3 is not applied evenly to the outer circumference of the focusing coil 2, but is concentrated near the screw 9. causing axis misalignment. As a result, asymmetry and inclination of the focusing magnetic field occur within the image pickup tube 3, and the focusing of the electron beam emitted within the image pickup tube 3 on the target surface becomes non-uniform, resulting in deterioration of color shading characteristics and reduction in peripheral resolution. It was the cause of In addition, since the body made of the glass tube of the image pickup tube 3 is tightened by the tightening band 8, there is a risk of damaging the image pickup tube 3 due to variations in the strength of the glass tube or variations in the tightening strength, so the workability is good. However, I could not say that.

(Purpose of the invention) The present invention was made in view of the drawbacks of the above-mentioned conventional example.
To provide a focusing device for an image pickup tube, which allows the image pickup tube to be correctly attached to the focusing coil without causing axis deviation, and improves workability by eliminating the risk of damage to the image pickup tube. be.

(Structure of the invention) In order to achieve the above object, the present invention consists of: a. a cylindrical coil bobbin made of a resin molded body around which a focusing coil is wound; and b. a rotary fixed plate screwed from one end of the coil bobbin. The coil bobbin has a large diameter inner circumferential surface and a small diameter inner circumferential surface coaxially connected via a tapered surface, a female thread is formed on the large diameter inner circumferential surface, and a rear and small diameter inner circumferential surface. A spring tongue protrudes from the end of the small-diameter inner peripheral surface so as to surround the opening. Further, the rotary fixing plate has a male thread on its outer circumferential surface that engages with a female thread on the large-diameter inner circumferential surface of the coil bobbin, and has an opening in the center or is made of a translucent material.

Then, the image pickup tube with the target ring or target ring and mesh ring protruding from the outer periphery is inserted into the coil bobbin, and the rotating and fixed plate is screwed in so as to press the end face of the image pickup tube in the axial direction. The image pickup tube is held by bringing the entire circumference into contact with the tapered surface and supporting the body with the spring tongue.

(Description of Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a diagram showing the configuration of an embodiment of the present invention. In FIG. 2, reference numeral 11 denotes a cylindrical coil bobbin made of a resin molded body, and its inner periphery has a large-diameter inner circumferential surface 12 and a small-diameter inner circumferential surface 13, and a tapered surface 14.
A female thread is formed on the inner circumferential surface 12 with a large diameter at the front, and a female thread is formed from the end of the inner circumferential surface 13 with a small diameter at the rear so as to surround the opening. A spring tongue piece 15 projects rearward. Further, 16 is a focusing coil wound around the outer periphery of the coil bobbin 11, and 17 is a magnetic shielding material that covers the focusing coil 16. 18 is the coil bobbin 11
This is an electrostatic deflection electromagnetic focusing type image pickup tube that is inserted and held in the camera, and a target ring 20 and a mesh ring 21 protrude from the outer peripheral surface of the rear face plate 19 on the front side. Here, the diameter of the large-diameter inner peripheral surface 12 of the coil bobbin 11 is the same as that of the target ring 20 and the mesh ring 21.
The diameter of the inner peripheral surface 13 is set to be larger than the outer diameter of the body of the imaging tube 18 and smaller than the outer diameter of the mesh ring 21. The mesh ring 21 is configured to abut on a tapered surface 14 that connects the mesh ring 12 and the small-diameter inner circumferential surface 13. In addition, 22 and 23
24 is a crystal filter and an infrared cut filter inserted into the large diameter inner circumferential surface 12, and 24 is a disk-shaped central filter having a threaded portion formed on the outer circumferential surface and screwed into the large diameter inner circumferential surface 12 of the coil bobbin 11. It is a rotary fixed plate that has an opening in the center or is made of a translucent material.

In the above configuration, when the imaging tube 18 is installed in this embodiment, the imaging tube 18 is inserted into the coil bobbin 11 from the front side of the large-diameter inner circumferential surface 12, and the spring tongue piece at the rear of the coil bobbin 11 is 1
5 supports the body of the rear part of the image pickup tube 18 and aligns the rear part of the image pickup tube 18, while the rear corner of the mesh ring 21 touches the tapered surface 14 in the coil bobbin 11.
The image pickup tube 18 is pushed in until it abuts the entire circumference, and the positioning of the image pickup tube 18 and the centering of the front part of the image pickup tube 18 are performed simultaneously. In this state, a crystal filter 2 necessary for a television camera is placed inside the large-diameter inner circumferential surface 12.
By screwing in the rotary fixing plate 24 after inserting the mesh ring 2 and the infrared cut filter 23, the rotary fixing plate 24 presses the face plate 19 of the image pickup tube 18 in the axial direction via the crystal filter 22 and the infrared cut filter 23.
1 is pressed against the tapered surface 14.
8 is held in the coil bobbin 11.

The image pickup tube 18 installed in the coil bobbin 11 in this way has its rear end attached to the spring tongue piece 15.
The image pickup tube 18 is held at the center of the coil bobbin 11 reliably, and the front part is aligned by bringing the mesh ring 21 into contact with the tapered surface 14 over the entire circumference. Since the mesh ring 21 is held pressed against the tapered surface 14 by the axial pressing force from the fixing plate 24, the image pickup tube 18 is
There will be no axis misalignment. Furthermore, in this embodiment, a crystal filter 22 and an infrared cut filter 23, which are essential for a television camera, are installed in the image pickup tube 1.
Since it can be installed in the coil bobbin 11 together with 8, the structure for attaching a filter that was conventionally provided between the image pickup tube bundle device and the lens of the television camera can be omitted, and the structure of the television camera is simplified. become.

In the above embodiment, the mesh ring 21 of the image pickup tube 18 is connected to the tapered surface 1 in the coil bobbin 11.
However, if the outer diameter of the target ring 20 is relatively larger than the outer diameter of the mesh ring 21 or if there is no mesh ring 21, the diameter of the small diameter inner circumferential surface 13 of the coil bobbin 11 should be brought into contact with the mesh ring 21. or the outer diameter of the body of the imaging tube 18 and the targeting ring 20
The outer diameter of the target ring 20 may be set smaller than the outer diameter of the target ring 20 so that the target ring 20 comes into contact with the tapered surface 14.

Further, the crystal filter 22 and the infrared cut filter 23 inserted into the small-diameter inner peripheral surface 12 may not be installed if they are not necessary depending on the type of the imaging tube 18 and the purpose of use.

Although the case where an electrostatic deflection electromagnetic focusing type image pickup tube 18 is used as an example has been described, the same effect can be obtained in the present invention even when an electromagnetic deflection electromagnetic focusing type image pickup tube is used. By providing a deflection coil instead of a focusing coil on the outer periphery of the coil bobbin of the present invention, it can also be used as a deflection device for an electromagnetic deflection/electrostatic focusing type image pickup tube, in which case the tilt of the deflection magnetic field can be prevented. Can be done.

(Effects of the Invention) As explained above, the present invention allows the coil bobbin to be pressed while the imaging tube is pressed in the axial direction so that the target ring or mesh ring of the image pickup tube comes into contact with the tapered surface inside the coil bobbin over the entire circumference. By holding the electron beam inside the image pickup tube, it can be installed without causing axis deviation or tilting with respect to the focusing coil of the image pickup tube. Therefore, the electron beam emitted within the image pickup tube is focused without bias or tilt, and is stable. Color-shading characteristics and resolution characteristics are obtained, and there is no risk of damaging the image pickup tube because the glass tube in the body of the image pickup tube is not tightened with a metal tightening band as in the conventional case. ,
The crystal filter and infrared cut filter, which are essential to a television camera, can be installed in the coil bobbin along with the image pickup tube, and the structure of the television camera is simplified because a structure for attaching the filter is not required as in the past. This has the effect of improving workability during assembly and reducing costs.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional focusing device for an image pickup tube.
FIG. 2 is a sectional view of an embodiment of the present invention. DESCRIPTION OF SYMBOLS 11... Coil bobbin, 12... Inner circumferential surface with large diameter, 13... Inner circumferential surface with small diameter, 14... Tapered surface, 16... Focusing coil, 18... Image pickup tube, 20
...Target ring, 21...Mesh ring, 24...Rotating fixed plate.

Claims (1)

[Scope of Claim for Utility Model Registration] A focusing device for an image pickup tube that holds an image pickup tube with a target ring or a target ring and a mesh ring protruding from the outer periphery, which includes: a) a cylindrical body made of a resin molded body around which a focusing coil is wound; Coil bobbin The coil bobbin has a large-diameter inner circumferential surface and a small-diameter inner circumferential surface coaxially connected via a tapered surface,
A female thread is formed on the large diameter inner circumferential surface, and a spring tongue protrudes from the rear end of the small diameter inner circumferential surface so as to surround the opening. b. A rotating fixing plate that is screwed onto the large-diameter inner circumferential surface of the coil bobbin. The rotating fixing plate has a male thread on its outer circumferential surface that engages with a female thread on the large-diameter inner circumferential surface of the coil bobbin, and has an opening in the center. or made of a translucent material. By screwing the rotary fixing plate so as to press the end face of the image pickup tube inserted into the coil bobbin in the axial direction, the target ring or mesh ring of the image pickup tube is brought into contact with the tapered surface on the entire circumference. and a focusing device for an image pickup tube, characterized in that the image pickup tube is held by supporting the body with the spring tongue piece.