JPH0597047U - Focus magnet for electronic lens - Google Patents

Abstract

(57) [Abstract] [Purpose] To remarkably extend the resonance frequency due to the L value (inductance) and the distributed capacitance of the dynamic coil based on the parabolic pulsating current flowing in the dynamic coil. [Structure] A static magnetic field in which a central cylindrical yoke is sandwiched and permanent magnets (only the permanent magnet may be omitted without the center yoke) are fixed to both end faces, and a static magnetic field is applied to the inner peripheral side surface. Equipped with dynamic magnetic field of coil and dynamic coil, plastic permanent magnet is applied to the permanent magnet that wraps the dynamic coil,
A focus magnet for an electron lens, characterized in that a static coil is formed by dividing two or more of the coils so that the outer sides of the coils are insulated from each other and connecting them in series.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement of a focus magnet for an electron lens, which is applied to, for example, adjusting the electromagnetic deflection of an electron beam emitted from an electron gun of a cathode ray tube.

[0002]

[Prior Art]

 FIG. 8 is a side sectional view of a main part showing a peripheral structure of a focus magnet for an electronic lens of this type as a conventional example. In FIG. 8, inside the glass bulb neck 7 of the cathode ray tube, an electron gun mechanism for emitting an electron beam B directed from the cathode 10 toward the anode 8 under the control of the first and second grids 9a and 9b. However, many developments have been made on so-called electron lenses that electromagnetically deflect the electron beam B so as to form an image on a cathode ray tube (not shown). This FIG. 8 itself is also a means to be the invention of the applicant. An electron beam B from the electron gun mechanism described above is provided with a center yoke 4 made of a ferromagnetic material in the central portion, and fixed magnets made of the same cylindrical permanent magnets 3a and 3b on both end faces. A static magnetic field for the electron lens is formed. Two types of coils are cascaded and arranged in this order from the electron gun side toward the cathode ray tube screen while inscribed on the inner peripheral side surface and circumscribed on the outer peripheral surface of the glass bulb neck portion 7 of the cathode ray tube stem. These two types of coils are the static coil 1 consisting of a hollow cylindrical coil that makes direct current flow and focuses the vicinity of the center of the Brown tube screen to create an electromagnetic field for initial adjustment. It is a hollow cylindrical dynamic coil 2 that applies a high-frequency current to focus near the screen of the cathode ray tube and creates an electromagnetic field for distortion correction. A dynamic magnetic field for an electron lens formed in this manner is provided. These center yokes 4 are sandwiched into permanent magnets 3a and 3b, and side yokes 5a and 5b made of a disk-shaped ferromagnetic material fixed to the permanent magnets on the outer end faces of the dynamic coil and the static coil. When equipped, it constitutes a focus magnet for an electronic lens. In this way, the electron beam B is appropriately deflected by the action of the magnetic flux φ by adjusting the static and dynamic magnetic fields of the focus magnet for the electron lens.

[0003]

[Problems to be solved by the device]

 However, in this conventional example, for example, the outer diameter of the glass bulb neck portion 7 of the cathode ray tube stem is 34 mm, the outer diameter of the side yoke is 58 mm, the thickness is 2.3 mm, the outer diameter of the permanent magnets 3a and 3b is 59 mm, and the thickness is Each 8 mm, static coil 1 has 560 turns of 0.18 mm diameter enamel wire for direct current, and dynamic coil 2 has 75 turns of 0.35 mm diameter enamel wire.・ The coil current flowing in the coil 2 is a parabola pulsating parabolic current as shown in FIG. Then, as shown in the drawing, the widths of the outermost diameter (3a, 3b) 59 mm and the innermost diameter (1, 2) 34 mm are halved so that the widths of the ring-shaped portions of the permanent magnets 3a, 3b and the coils 1, 2 are divided. Is set, and each coil is stored in the bobbin 6. Under such conditions of the conventional example, the frequency characteristic of the parabolic current of the inductance L of the dynamic coil 2 is a characteristic curve 51 shown by the dotted line in FIG. As is clear from this, it has a peak value near a frequency of 140 KHz, and a characteristic curve appears before and after that, and the frequency band used as the dynamic coil 2 is about 130 KHz at most. The narrow frequency band used in this way has been a bottleneck in improving image quality and other quality. Here, in order to solve the problems of the conventional example, the present invention aims to provide a focus magnet for an electronic lens, which is provided with a means in which a dynamic coil or a static coil is wound separately. And

[0004]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a magnet in which permanent magnets are fixed to both end surfaces of a cylindrical center yoke, and a hollow cylindrical static coil and a dynamic coil are arranged on the inner peripheral surface of the magnet. In the focus lens for electron lenses, which has a permanent magnet, a static coil, and a disk-shaped side yoke fixed to the permanent magnet on the outer end surface of the dynamic coil, a static coil or a static coil and a dynamic coil are used. A focus magnet for an electronic lens, characterized in that the outer sides of the coils are insulated and covered into two or more divided pieces. Further, a plastic permanent magnet is used for the permanent magnet enclosing the dynamic coil. Apply the static coil to each other and insulate the outside of the coil. A focus magnet for an electronic lens, which is characterized by being configured into two or more divided parts. Furthermore, a plastic permanent magnet is applied to the permanent magnet enclosing the dynamic coil, and the dynamic coils are mutually coiled. This is a focus magnet for an electron lens, characterized in that it is constructed by dividing the outside of the core into two or more divided pieces, and instead of disposing the center yoke, the whole part is permanent. A focus magnet for an electron lens, which is composed of a static coil or a static coil and a dynamic coil which are formed into two or more divided pieces in which the outer sides of the coils are insulated and covered with each other. Is.

[0005]

[Action]

 The fact that there is electromagnetic coupling between the static coil and the dynamic coil can be easily inferred from the arrangement of both parties, but one of these coils is divided, and each of the divided small coils is insulated and coated into a single coil. By providing the function as a static coil or a dynamic coil, the equivalent electrostatic capacity of those coils is significantly reduced, and as a result, the frequency characteristic of the inductance L of the dynamic coil is improved much more than the conventional example. For example, in the case of two-division, it extends to about twice [the peak value extends from the conventional 140 KHz to 280 KHz].

[0006]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 is a block diagram showing the circuit configuration of an embodiment of the present invention. In the drawings, the same symbols represent the same or corresponding members. In FIG. 1, a static magnetic field is formed by arranging a center yoke 4 made of a cylindrical ferromagnetic material at the center and fixing magnets 3a, 3b made of the same cylindrical permanent magnet on both end faces. .. A static coil 1 and a dynamic coil 2 are arranged in this order from the electron gun side to the screen of the cathode ray tube, which are inscribed on the inner peripheral side surface and circumscribed on the outer peripheral surface of the cathode ray tube stem portion 7, and are housed in the bobbin 6. .. The static coil 1 is divided into two small static coils 1a and 1b [in the previous example, it was 560 times, but in this embodiment, it was 280 times x 2 times. In addition, both small static coils 1a and 1b are covered with an insulating material to insulate each other as if they were coils with different functions, but they are connected in series and placed at the same position as the conventional example. Arrange. The dynamic coil 2 is the same as that of the conventional example shown in FIG. Due to the arrangement of both the dynamic coil 2 and the static coil 1, both are electromagnetically coupled, and it is not possible to divide the static coil 1 into two small static coils 1a and 1b. 6, the capacitance of the coil changes from left to right with the arrow, and the frequency characteristic of the parabolic current flowing through the dynamic coil 2 extends.

FIG. 2 is a side sectional view of a main part of another embodiment of the present invention. In the other embodiment, the static coil 1 is divided into two or more pieces in which the outer sides of the coils are insulated and insulated from each other to form static coils 1a and 1b, which are electrically connected to each other outside the coils. Is. Alnico cast magnets are generally used for the permanent magnets 3a and 3b formed in the embodiment of FIG. 1, but since the specific resistance is low, there is an eddy current loss due to the interlinking magnetic flux. The loss will increase. Therefore, the powder of the alcomagnet described in the previously proposed patent application [name of invention / electron lens, filing date / June 20, 1991], a polyamide resin, and a flame retardant were mixed together, and further in a magnetic field. Another embodiment is a method in which a plastic permanent magnet formed by molding is applied to a permanent magnet enclosing a dynamic coil. Since this Alnico plastic permanent magnet is made by hardening magnet powder with resin, it has high specific resistance and small eddy current loss at high frequencies. By the way, the static coil 1 has many coil turns in order to increase its sensitivity. Therefore, the inductance [L value] of the coil is large, and the resonance frequency peculiar to the coil due to the inductance of the coil and the distributed capacitance [capacitance] is low, and the resonance frequency is within the operating frequency band of the dynamic coil 2 or near its upper limit frequency. There will be frequencies. As described above, since the static coil 1 and the dynamic coil 2 are electromagnetically coupled to each other, the influence of the resonance phenomenon appears within the operating frequency band of the dynamic coil 2 or near its upper limit frequency, and the dynamic coil 2 2) The sensitivity variation in the used frequency band becomes large. Further, since a high-frequency parabolic current is passed through the dynamic coil 2, the inductance L value of the dynamic coil 2 is small and is generally 1 mH (millimeter-henry) or less. Therefore, the dynamic coil 2 is in a higher frequency region than the resonance frequency of the static coil 1. For this reason, the distributed capacitance is equivalently reduced by dividing the static coil 1 into the small static coils 1a and 1b, so that the resonance frequency of the inductance L value of the dynamic coil 2 can be reduced. Can be higher. The characteristic curve 52 of the embodiment is shown by the solid line in FIG. 5, and the resonance frequency is doubled as compared with the characteristic curve 51 of the conventional example.

FIG. 3 is a side sectional view showing the main part of another embodiment of the present invention. In this alternative embodiment, the dynamic coil 2 is divided into small dynamic coils 2a and 2b as well as the small static coils 1a and 1b. The operation and effect are substantially the same as those of the other embodiment shown in FIG.

FIG. 4 is a side sectional view showing the main part of another embodiment of the present invention. In the above-described embodiments, the center yoke 4 made of a ferromagnetic material having a cylindrical shape is disposed in the central portion, and the magnets 3a, 3b made of the same cylindrical permanent magnet are fixed to both end surfaces to form a static structure. A magnetic field is provided. However, in the other embodiments, the center yoke 4 is not provided, and a static magnetic field is provided by the magnet 3 composed of a cylindrical permanent magnet, and the permanent magnet 3 is fixed to both outer end surfaces of the permanent magnet 3. It is provided with side yokes 5a and 5b made of a disk-shaped ferromagnetic material. The static coil 1 is divided into two small static coils 1a and 1b. Although not shown, the dynamic coil 2 may be divided into small dynamic coils 2a and 2b as well as divided into small static coils 1a and 1b. Done. The operation and effect of the other embodiments are almost the same as those of the embodiment of FIG.

[0010]

[Effect of the device]

 Thus, according to the present invention, the built-in static coil or both the static coil and the dynamic coil are separately wound, thereby extending the resonance frequency specific to the coil and transmitting the high-frequency signal to the dynamic coil. It is possible to shift the frequency characteristics of the dynamic coil to the higher frequency side to widen the frequency band used, and the reliability of the focus magnet for electronic lenses is improved due to the remarkable improvement in image quality. It is possible to achieve the effect of being particularly improved.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a configuration of a main part in an embodiment of the present invention.

FIG. 2 is a side sectional view showing the configuration of the main part of another embodiment of the present invention.

FIG. 3 is a side sectional view showing a configuration of a main part in another embodiment of the present invention.

FIG. 4 is a side sectional view showing a configuration of a main part in another embodiment of the present invention.

FIG. 5 is a comparison diagram of characteristic curves showing changes in the dynamic coil L value and changes in the resonance frequency in another example of the present invention and a conventional example.

FIG. 6 is an explanatory diagram of an equivalent electric circuit of the coil dividing means of the present invention.

FIG. 7 is an explanatory view of a parabolic current flowing through the dynamic coil of the present invention.

FIG. 8 is a side sectional view showing a configuration of a main part of a conventional example.

[Explanation of symbols]

 1 static coil 1a static coil 1b static coil 2 dynamic coil 2a dynamic coil 2b dynamic coil 3 permanent magnet 3a permanent magnet 3b permanent magnet 3c plastic permanent magnet 4 center yoke (ferromagnetic material) 5a side yoke (Ferromagnetic material) 5b side yoke (ferromagnetic material) 6 bobbin (electrical insulator) 7 glass bulb neck 8 anode 9a first grid 9b second grid 10 cathode B electron beam φ magnetic flux

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Takayuki Matsumoto 1-4-2-4, Shiromi, Chuo-ku, Osaka-shi, Osaka NEC Home Electronics Co., Ltd.

Claims (4)

[Scope of utility model registration request] 1. A permanent magnet and a static coil in which a permanent magnet is fixed to both end surfaces of a cylindrical center yoke, and a hollow cylindrical static coil and a dynamic coil are disposed on the inner peripheral surface of the magnet. And a disk-shaped side fixed to a permanent magnet on the outer end surface of the dynamic coil.
A focus magnet for an electron lens having a yoke, characterized in that a static coil or a static coil and a dynamic coil are formed into two or more divided pieces in which the outer sides of the coils are insulated and covered. Focus magnet for electronic lens. 2. A permanent magnet and a static coil in which a permanent magnet is fixed to both end surfaces of a cylindrical center yoke, and a hollow cylindrical static coil and a dynamic coil are arranged on the inner peripheral surface of the magnet. And a disk-shaped side fixed to a permanent magnet on the outer end surface of the dynamic coil.
In a focus magnet for an electron lens equipped with a yoke, a plastic permanent magnet is applied to the permanent magnet that wraps the dynamic coil, and the static coil is made into two or more divided pieces in which the outer sides of the coils are insulated and covered. A focus magnet for electronic lenses, which is characterized by its construction. 3. A magnet having permanent magnets fixed to both end surfaces of a cylindrical center yoke, and a hollow cylindrical static coil and dynamic coil arranged on the inner peripheral surface of the magnet. And a disk-shaped side fixed to a permanent magnet on the outer end surface of the dynamic coil.
In a focus magnet for an electron lens equipped with a yoke, a plastic permanent magnet is applied to the permanent magnet that wraps the dynamic coil, and the dynamic coil is made into two or more divided pieces in which the outer sides of the coils are insulated and covered. A focus magnet for electronic lenses, which is characterized by its construction. 4. A magnet having a permanent magnet fixed to both end faces of a cylindrical center yoke, and a hollow cylindrical static coil and a dynamic coil arranged on the inner peripheral surface of the permanent magnet and the static coil. And a disk-shaped side fixed to a permanent magnet on the outer end surface of the dynamic coil.
A focus magnet for an electron lens having a yoke, characterized in that a static coil or a static coil and a dynamic coil are formed into two or more divided pieces in which the outer sides of the coils are insulated and covered. Focus magnet for electronic lens.