JPH0724200B2 - Deflection device for color picture tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a deflector for a color picture tube, and more particularly to a deflector for a color picture tube having an in-line type electron gun.

(Prior Art) In general, a color picture tube having an in-line type electron gun has an arrangement direction of electron beams (70) as shown in FIG. 7 in principle as described in JP-A-54-75215. When the horizontal direction is set to the horizontal direction, the magnetic field generated from the vertical coil is the barrel distribution magnetic field (71), and the magnetic field generated from the horizontal deflection coil is the pincushion distribution magnetic field (72). Is corrected to reproduce an image having a good convergence characteristic. Generally, such a method is called a self-convergence method. However, in so-called display tubes that require high performance for image display, large deflection angles such as 110 ° deflection type color picture tubes, and full square type color picture tubes with a smaller screen curvature, as described above. The required performance cannot be satisfied only by the self-convergence method. In order to satisfy such high required performance, the color picture tube deflector is generally constructed as follows.

That is, as shown in a partially cutaway structural view in FIG. 3, the deflecting device (1) for a color picture tube is made of synthetic resin, for example, a polypropylene conical mold having a horizontal deflection coil (not shown ) inside. (4), toroidal core (2) and vertical deflection coil (3) wound around this core
And a magnetic body (5) composed of a pair of plate-shaped silicon steel plates arranged between the conical mold (4) and the toroidal core (2). The magnetic body (5) is composed of magnetic pieces (51) and (52) as schematically shown in FIG. 4, and has a tube axis central axis (z axis) of a color picture tube.
Are symmetrically arranged with respect to the vertical deflection direction (y-axis). A part (51) of this direction magnetic piece (51), (52)
s) and (52s) are arranged between the vertical deflection coil (3) and the horizontal deflection coil (6).

Next, the function of the magnetic material will be described.

The vertical magnetic field of the deflection device for a color picture tube which does not include the magnetic substance forms a barrel-shaped magnetic field (40) from the electron gun direction to the screen direction as shown by the dotted line in FIG. The left and right rasters generate pincushion type distortion, and the magnitude of this distortion is about 8% in a 110 ° deflection type color picture tube. Usually, the correction is made in the deflection circuit for the color picture tube. However, in the above-mentioned display tube, since higher performance convergence characteristics are required, as shown by the solid line in FIG. 5, the pincushion type is strengthened in the screen direction and the barrel type is strengthened in the electron gun side. Magnetic field correction is performed to form a magnetic field (30). The magnetic body is used to strengthen the barrel-shaped magnetic field on the electron gun side. As shown in the schematic cross-sectional view in the direction perpendicular to the z axis in FIG. 6, the magnetic pieces (61) and (62) are symmetrical with respect to the x axis (horizontal deflection direction) along the y axis (vertical deflection direction). The vertical deflection magnetic field (81) is arranged so that the magnetic pieces (61) and (6
The magnetic field (82) is strengthened in the barrel direction by 2). Further, as is clear from FIG. 6, the magnetic piece (6
Since 1) and (62) are arranged perpendicular to the horizontal deflection (x axis), they have almost no effect on the horizontal deflection magnetic field (83). The above magnetic material is generally used in a deflecting device for a high-performance color picture tube such as a 110-degree deflecting tube.

Normally, the horizontal deflection frequency of a color picture tube is 15.75KHz, but in the case of a color picture tube that requires high resolution and high visibility, the usage conditions of high horizontal deflection frequency are increased, such as 25KHz and 31KHz. . Especially computer-based technical design or production control, so-called CAD (Computer Aided
Color picture tubes used in Design) and CAM (Computer Aided Manufacturing) applications may operate at a horizontal deflection frequency of 64 KHz.

(Problems to be Solved by the Invention) When the deflection device is operated at the high horizontal deflection frequency as described above, the following problems occur.

That is, the horizontal magnetic field generates an eddy current in the core and the horizontal deflection coil that form the deflection device, and heat is generated. Heat generation can be suppressed by using a material having a higher resistance for the core, and by using a litz wire for the horizontal deflection coil. However, it is quite difficult to suppress heat generation of the magnetic material. Especially the 4th
Parts (51s), (5) sandwiched between the vertical deflection coil (3) and the horizontal deflection coil (6) of the magnetic pieces (51), (52) shown in the figure.
The fever of 2s) is abnormally large in some cases.

Generally, the eddy current loss δe of thin plate-shaped magnetic material is Given in. Here, d is the thickness of the thin plate-shaped magnetic material, μ is the magnetic permeability of the magnetic material, f is the horizontal deflection frequency, and ρ is the specific resistance of the magnetic material. That is, the temperature rise of the magnetic body due to the eddy current loss rises in proportion to the horizontal deflection frequency. FIG. 8 shows the results obtained by the experiments conducted by the inventors of the present invention regarding the temperature rise of the magnetic piece when the deflection device for the 26-inch 110 ° deflection type color picture tube is operated at various horizontal deflection frequencies. Particularly, Is is the temperature rise of the portions (51s) and (52s) disposed between the vertical deflection coil (3) and the horizontal deflection coil (6) of the magnetic pieces (51) and (52) in FIG. Is. The characteristic Ic is substantially the center of the magnetic pieces (51) and (52), that is, the portions (51c) and (52) that do not face the horizontal deflection coil (6).
It shows the temperature rise of c). From FIG. 8, it was found that the maximum temperature of the magnetic piece reached up to 90 ° C. when operated at 64 KHz, and it was also found that there was a considerable temperature difference depending on the part of the magnetic piece.

By the way, the heat-resistant temperature of commonly used polypropylene molds (the temperature at which thermal deformation begins to occur)
Is about 105 ° C. Then, when the outside air temperature is 50 ° C and the horizontal deflection frequency of the 26 inch 110 ° deflection color picture tube deflection device is operated at 64 KHz, the magnetic piece is
Since the temperature rises to about 90 ℃, the temperature in the vicinity is 140 ℃.
As the mold becomes closer, thermal deformation of the polypropylene mold progresses, causing serious problems in terms of characteristics and reliability. As one method of suppressing the above-mentioned temperature rise, it is conceivable to reduce the plate thickness (d) of the magnetic body as is clear from the above formula (1), but if the plate thickness is made too small, the magnetization characteristics It is not practical because it causes a problem such as deterioration and easy deformation.

The present invention has been made in view of the above-mentioned drawbacks of the color picture tube deflection apparatus, and an object of the present invention is to provide a deflection apparatus that generates little heat and is stable even when operating at a high horizontal deflection frequency.

[Structure of Invention]

(Means for Solving the Problems) The present invention is a deflection device for a color picture tube, wherein a film having a thermal conductivity larger than that of a magnetic piece is formed on the surface of a magnetic body that constitutes the deflection device.

(Function) The coating formed on the surface of the magnetic material has a higher thermal conductivity than the magnetic material, and its specific surface area is about 50 times that of the magnetic material, which greatly improves the thermal emissivity of the magnetic material. Controls temperature rise.

(Embodiment) An embodiment of the deflection device for a color picture tube of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic view showing a part of a magnetic body constituting a deflector for a color picture tube to which the present invention is applied. The arrangement of the magnetic body in the deflecting device is the same as that of the deflecting device shown in FIG. FIG. 1 shows a part of a pair of magnetic pieces arranged symmetrically with respect to the central axis (z axis) of the tube axis as shown in FIG. The magnetic piece (50) in FIG. 1 is made of a silicon steel plate, and a ceramic layer (10) is formed on the surface of the silicon steel plate.
Are formed. This ceramic layer is, as in the following examples, silicon containing silicon carbide (SiC) as a filler and a zirconia alkoxide compound, for example, a suspension of ZrSi (OC ₄ H ₉ ) ₄ is applied by a spray method, The film is heat-treated after forming a film having a thickness of about 10 μm.

Example SiC 500gr Silicon and zirconia alkoxide compound 100gr Isopropyl alcohol 400gr A spray method is suitable for applying this suspension. In this case, the spray pressure is about 3kg / cm ² from a distance of 20cm to 30cm. An example film of about 10 μm can be formed in about 3 seconds. Thus, by heating the silicon steel sheet coated with the suspension containing the alkoxide compound of silicon and zirconia in an atmosphere of 70 ° C. or higher, the ceramic layer containing SiC as a main component (1
0) can be obtained. The alkoxide compound of silicon and zirconia applied to this magnetic piece (50) undergoes hydrolysis due to moisture in the atmosphere in an atmosphere of 70 ° C or higher,
As a result, a film is formed by the polycondensation reaction between the alkoxides, forming a ceramic layer as a SiC binder. In the above example, the suspension was heated after application, but if the suspension is applied while heating at 70 ° C. or higher in order to shorten the manufacturing time, the subsequent heat treatment step can be omitted. Further, since the silicon and zirconia alkoxide compounds have good absorption characteristics of electromagnetic rays in the infrared region, when hydrolyzing, the alkoxide compound of silicon and zirconia containing SiC as a main component is not in an atmosphere of 70 ° C or higher. The surface of the magnetic piece (50) to be coated with is coated with a suspension containing silicon and zirconia alkoxide compounds containing SiC as the main component while irradiating with infrared rays, for example, and sufficient hydrolysis is performed even at room temperature. Was also confirmed. It is also possible to irradiate infrared rays after coating.

Here, the present inventors have conducted detailed experimental studies on the temperature rise of the magnetic piece when the 26-inch 110 ° C. deflection type color picture tube is operated by the deflection device to which the present invention is applied. That is,
FIG. 2 shows the results, where the horizontal axis shows the thickness of the ceramic layer (10) containing silicon and zirconium metal oxide whose main component is SiC, and the vertical axis shows the magnetic piece (50). The temperature rise during operation is shown as a relative value based on the case where the ceramic layer is not formed. From this figure, it was found that the temperature rise of the magnetic piece was remarkably suppressed by forming the ceramic layer containing the metal oxide of silicon and zirconium containing SiC as the main component on the surface of the magnetic piece. This is because the thermal conductivity of the ceramic layer formed on the surface of the magnetic piece is about 1.0 cal / cm ・ sec ・ deg, which is much higher than 0.02 cal / cm ・ sec ・ deg of the magnetic piece made of silicon steel sheet. Furthermore, the specific surface area of the ceramic layer is about 50 times larger than that of the magnetic piece, in other words, the surface area of the ceramic layer is about 50 times larger than that of the magnetic piece, so that the thermal emissivity is also greatly improved. That is, when the operation is started, heat is generated in a part (51s), (52s) of the magnetic piece facing the horizontal deflection coil (6) shown in FIG. 4, but a ceramic layer having a high thermal conductivity is formed on the surface of the magnetic piece. This is because the temperature rise is suppressed by heat conduction and the heat radiation from the surface of the ceramic layer having a high heat emissivity increases. This is the characteristic IIc in FIG.
Is the temperature rise of the portion of the magnetic piece facing the horizontal deflection coil according to the present invention, which is 40% higher than that of the conventional magnetic piece.
Although the temperature rise is suppressed to some extent, the central portion of the magnetic piece that does not face the horizontal deflection coil is
It can be understood from the fact that it is suppressed only by about 20%. The specific surface area was measured by the BET method calculated from the adsorption amount of nitrogen gas at low pressure. On the other hand, in FIG. 2, when the thickness of the ceramic layer is about 10 μm or more, the temperature suppressing effect is saturated. This is because when the thickness of the ceramic layer is thick, the ceramic layer close to the surface of the magnetic piece, in other words, the ceramic layer It is considered that the lower layer does not contribute so much to the improvement of heat dissipation, but only the surface layer region of the ceramic layer greatly contributes to heat dissipation. It should be noted that it is clear that the ceramic as in the embodiment of the present invention has a high electric insulating property and is a non-magnetic material, so that it does not affect the original magnetic action of the magnetic material. Further, a ceramic layer containing metal oxides of silicon and zirconium,
Since it is possible to sinter at a low temperature, the magnetic characteristics of the magnetic piece are never altered by the temperature at which the ceramic layer is sintered, and it can be said that the mass productivity is high in this respect as well.

On the other hand, in the embodiment of the present invention, the magnetic body shapes only the vertical deflection magnetic field in the barrel direction, but the embodiment of the present invention is not limited to such a magnetic body, and allows the magnetic field to be shaped widely. It can be applied to a magnetic material, and a ferromagnetic material other than a silicon steel plate can be used.

〔The invention's effect〕

As described above, according to the present invention, it is possible to obtain a highly reliable deflector for a color picture tube which does not generate heat in a magnetic material even at a high horizontal deflection frequency.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a magnetic body constituting a color picture tube deflector according to the present invention, FIG. 2 is a characteristic diagram showing a temperature rise during operation of the magnetic body according to the present invention, and FIG. 3 is a color picture tube deflection. FIG. 4 is a partial switching structure diagram of the apparatus, FIG. 4 is an enlarged cross-sectional view for explaining the arrangement of magnetic bodies in a conventional color picture tube deflecting device, and FIG. 5 is a characteristic diagram for explaining the effects of the magnetic bodies. FIG. 7 is a schematic sectional view showing the arrangement of magnetic bodies, and FIG. 7 is a schematic sectional view for explaining a deflection magnetic field in a color picture tube,
FIG. 8 is a characteristic diagram showing a temperature rise during operation of a magnetic body attached to a conventional deflection device. (1) ...... Deflection device (2) ...... Core (3) ...... Vertical deflection coil (4) ...... Mold (5) ...... Magnetic material (50), (51), (52), (61), (62) …… Magnetic piece (10) …… Ceramic layer

Claims (1)

[Claims] 1. A deflection device for a color picture tube, comprising a conical mold having a horizontal deflection coil inside and a toroidal core around which a vertical deflection coil is wound. A deflection device for a color picture tube, comprising a ceramic layer containing an alkoxide compound of silicon and zirconia containing silicon carbide on the surface of the body.