JPH0682542B2 - Deflection device for color picture tube - Google Patents

Description

The present invention relates to a color picture tube deflector, and more particularly to a color picture tube deflector having an in-line electron gun.

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

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

Next, the operation of the magnetic piece will be described.

The vertical magnetic field of the deflection device for a color picture tube which does not include the magnetic piece forms a barrel-shaped magnetic field (51) 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 amount of this distortion is about 4% in a 90 ° deflection type color picture tube. Normally, the deflection circuit for a color picture tube corrects it, but in the display tube described above, higher performance convergence characteristics are required.
As shown by the solid line in FIG. 5, magnetic field correction is performed so as to form a stronger magnetic field (52) in the pincushion shape in the screen direction and in the barrel shape on the electron gun side. The magnetic piece is used to enhance 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 (6a) and (6b) are symmetrical with respect to the x-axis (horizontal deflection direction) along the y-axis (vertical deflection direction). The vertical deflection magnetic field ( 61 ) is shaped into a magnetic field (62) reinforced in the barrel direction by the magnetic pieces (6a) and (6b).
As is apparent from FIG. 6, since the magnetic pieces (6a) and (6b) are arranged perpendicular to the horizontal deflection (x axis), they have almost no influence on the horizontal deflection magnetic field ( 63 ). The above-mentioned magnetic piece is generally adopted in a deflector for a high-performance color picture tube such as a display tube.

Normally, the horizontal deflection frequency of a color picture tube is 15.75 KHz, but for display tubes and the like that require high resolution and high visibility, there are increasing conditions under which the horizontal deflection frequency is high, such as 25 KHz and 31 KHz. Especially, so-called CAD (Computer Aid)
ed Design) and CAM (Computer Aided Manufacturin
g) Display tubes used for applications may operate at a horizontal deflection frequency of 64 KHz.

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 causes eddy currents to be generated in the core and the horizontal deflection coil forming 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.

(Problems to be Solved by the Invention) However, it is quite difficult to suppress heat generation of the magnetic piece.

Generally, the eddy current loss δe of a 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. When the deflection device for a 14-inch 90 ° deflection type display tube is operated at a conventional horizontal deflection frequency, the temperature rise ΔT of the magnetic piece is about 20 ° C. as shown in FIG. However, when operated at 64 KHz, the ΔT is about 70 ° C.

By the way, the heat resistant temperature of a polypropylene mold (the temperature at which thermal deformation is said to occur) is about 105 ° C. Therefore, when the 14-inch 90-degree deflection type display tube deflection device was operated at a horizontal deflection frequency of 64 KHz in a place where the outside air temperature was 50 ° C., the magnetic piece increased by about 70 ° C. as shown in FIG. Is close to 120 ° C, the polypropylene mold is thermally deformed, which is a serious problem in terms of characteristics and reliability.
As one method of suppressing the above-mentioned temperature rise, as apparent from the above formula (1), the plate thickness (d) of the magnetic piece is
Although it may be possible to reduce the thickness, it is not practical to reduce the thickness too much because the magnetic properties deteriorate and the material is easily deformed.

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

[Structure of Invention]

(Means for Solving the Problems) That is, a ceramic layer is formed on at least one surface of a component of the deflection device by using amorphous silicon oxide or silicon hydroxide or a mixture thereof as a binder. A deflection device for a color picture tube, wherein the layer contains at least one oxide selected from the group consisting of cobalt, manganese, copper, chromium, iron, titanium and aluminum.

(Function) The thermal emissivity of the ceramic layer formed on the surface of the magnetic piece is high and the thermal radiation characteristic is significantly improved, so that the temperature rise of the magnetic piece is suppressed.

Embodiment An embodiment 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 piece (10) which is one of the components constituting the deflecting device for a color picture tube according to the present invention. The arrangement of the magnetic piece (10) in the deflecting device is the same as that of the conventional deflecting device shown in FIGS. 3 and 4. As shown in Fig. 4, Fig. 1 shows the central axis (Z
It shows a part of a pair of magnetic pieces arranged symmetrically with respect to the (axis). The magnetic piece (10) shown in FIG. 1 is made of a silicon steel plate, and a ceramic layer (11) using amorphous silicon oxide or silicon hydroxide or a mixture thereof as a binder is formed on the surface of the silicon steel plate. This ceramic layer is used as a filler such as iron, manganese, and
A suspension of a silicon alkoxide compound containing an oxide of aluminum, titanium, copper or the like, for example, Si (O (CH ₃ ) ₂ CH) ₄ , was applied by brushing to form a film of about 15 μm. In addition, it is better to add an organic acid in order to further improve the strength and density of the film.

Example Manganese / copper / chromium / aluminum / titanium oxide mixture
300g Silicon alkoxide compound 100g Organic acid 1g Isopropyl alcohol 599g Thus, by heating a silicon steel sheet coated with a suspension containing a silicon alkoxide compound and an organic acid in an atmosphere of 70 ° C or higher, A ceramic layer (11) containing a mixture of manganese / copper / chromium / aluminum / titanium oxide as a main component was obtained as shown in FIG. That is, the silicon alkoxide compound applied to the magnetic piece (10) is 70
This is because hydrolysis is caused by moisture in the air in a short time in an atmosphere at a temperature of ℃ or more, and as a result, a film is formed by a polycondensation reaction of alkoxides, and a ceramic is formed as a binder of the metal oxide. Also, since the suspension contains an organic acid as an accelerator, a hard and dense film can be formed. In the above example, the suspension was heated after coating, but in order to further shorten the manufacturing time,
If the suspension is applied while heating at 70 ° C or higher, the subsequent heat treatment step can be omitted. Here, the present inventors
The temperature rise of the magnetic piece when a 14 ″ 90 ° deflection type display tube was operated by the deflection apparatus to which the present invention was applied was studied in detail. That is, in FIG. 2, the horizontal axis represents the thickness of the ceramic layer. The vertical axis represents the temperature rise of the magnetic piece during operation, and is shown as a relative value with reference to the case where the ceramic layer is not formed. It was found that the temperature rise of the magnetic piece was suppressed by forming a black ceramic film consisting of a dense mixture of oxides such as manganese, copper, chromium, aluminum and titanium. This is because the black ceramic layer formed on the surface has an emissivity of 0.9 or more in the entire infrared region, and thermal radiation is greatly improved.

On the other hand, in FIG. 2, the temperature suppression effect saturates when the thickness of the ceramic layer is around 10 μm. This means that when the thickness of the ceramic layer becomes thicker, the ceramic layer closer to the surface of the magnetic piece, in other words, the deeper layer of the ceramic layer. Is considered to be because the thermal radiation does not contribute so much to the thermal radiation, and only the skin area of the ceramic layer contributes significantly to the thermal radiation.

Next, apply a ceramic layer to the horizontal deflection coil in the same manner as above.
It was formed with a thickness of μm, and the temperature change during operation was examined. As a result, it was about 46 ℃ without treatment, but it could be lowered to 37 ℃ by forming the ceramic layer.

Further, this time, a ceramic layer having a thickness of 15 μm was similarly formed on a polypropylene conical mold by the same means as above, and the temperature change during operation was examined. As a result, it was possible to reduce the temperature from about 44 ℃ without treatment to about 30 ℃.

〔The invention's effect〕

As described above, by providing the black ceramic layer, it is possible to significantly improve the thermal emissivity of the components forming the deflecting device and suppress the temperature rise thereof.

[Brief description of drawings]

FIG. 1 is a sectional view of a magnetic piece showing an embodiment according to the present invention,
FIG. 2 is a graph showing the relationship between the temperature rise of the magnetic piece and the film thickness of the ceramic layer, FIG. 3 is a partially cutaway side view of the deflection device, FIG. 4 is a schematic view of the magnetic piece, and FIG. 5 is the magnetic piece. FIG. 6 is a characteristic diagram for explaining a change in the vertical deflection magnetic field due to the magnetic field, FIG. 6 is a schematic sectional view for explaining the arrangement of magnetic pieces and the vertical and horizontal deflection magnetic fields, and FIG. 7 is a deflection magnetic field in a color picture tube. FIG. 8 is a schematic cross-sectional view showing the relationship between the magnetic piece of the conventional deflection device, temperature, and horizontal deflection frequency. (1) Deflection device (2) Core (3) Vertical deflection coil (4) Mold (5), (5a), (5b), (6a), (6b), (10) ......
Magnetic piece (11) …… ceramic layer

Claims (3)

[Claims] 1. A cone-shaped mold having a horizontal deflection coil inside, a toroidal core, a vertical deflection coil wound around the core, and a space between the mold and the toroidal core. A deflection device for a color picture tube, comprising at least a magnetic substance disposed therein, wherein at least one surface of a component constituting the deflection device is a ceramic using a binder of amorphous silicon oxide or silicon hydroxide or a mixture thereof. A deflection device for a color picture tube, characterized in that layers are formed. 2. The ceramic layer contains at least one oxide selected from the group consisting of cobalt, manganese, copper, chromium, iron, titanium, and aluminum. Deflection device for a color picture tube as described. 3. The deflection device for a color picture tube according to claim 1, wherein the ceramic layer is black.