JPS608367Y2 - Bobbin for focus coil for image pickup tube - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a bobbin for a focus coil (including a winding jig in the case of a bobbinless type) used in an electromagnetic focusing type image pickup tube.

In an imaging apparatus using an electromagnetic focusing type image pickup tube, for example, a vidicon tube, as is well known, a deflection coil is wound around the outside of the image pickup tube, and a focus coil is wound around the outside of the deflection coil.

(A deflection coil may be wound around the outer circumference of the focus coil.

) As shown in Fig. 1, this focus coil is a Tsuremade coil wound around a cylindrical bobbin 2 having flanges 1 and 1 at both ends, and its dimensions are approximately 40 m/m in diameter in the case of a vidicon tube. The majority are front and back with a length of 100 tn/m, each layer having around 200 tn/m, and the number of layers being about 10.

In addition, the outer diameter of the copper wire used is currently around 0.4 yn/thickness in most cases.

Ideally, the focus coil should be as shown in Figure 2.
The winding of the first layer is wound exactly between the flanges 1.1 of the bobbin 2, the winding of the second layer is wound between the winding of the first layer and the winding of the third layer. It is necessary to wind the windings in the same manner as in the first layer, and then to sequentially wind the windings as described above, and to wind the windings so that only at the fold line 3, each winding crosses at substantially the same angle θ.

However, in reality, there are slight errors in the copper wire diameter and bobbin dimensions. For example, if there is a maximum error of 1/100 in the copper wire diameter, there will be a gap of up to 2 m/m between the bobbin flange and the winding for 200 turns. This will occur between the lines.

In addition, even if the copper wire diameter has an accuracy of 171,000, the error at the end of the winding will be even greater than the number of returns, so the copper wire 1
It used to be common sense that the main quantile occurred as an error.

In an imaging device such as a black-and-white camera where peripheral resolution, screen distortion, shading, etc. are not so important, even the above-mentioned error does not cause much of a problem.

However, in imaging devices that handle multiple signals in which color signals are mixed with luminance signals, such as a single-tube color system, color unevenness occurs especially if the peripheral resolution is not uniform, so the error of the conventional coil described above is There were serious drawbacks that affected camera quality.

In addition, conventionally, focus coils have been analyzed only in terms of direct current, but in actual operation they have a relatively high coupling coefficient with the magnetic field of the deflection coil flange, and due to the inductance and stray capacitance between the focus coils, there is a possibility of divergence or absorption. Configure a resonant system.

As described above, in conventional focus coils, gaps occur at the ends of the layer windings due to variations in copper wire diameter and bobbin dimensions.

The shape of this gap differs from the angle θ at the transition point at the beginning of winding due to the elasticity of the copper wire and the winding tension, and θ is 9.
The state is close to 0°, the turning point becomes vague, and as the layers are stacked, the windings at both ends of the coil may fall off, or gaps may randomly occur between the windings.

In a focus coil wound in this way, the inductance and capacitance inside the coil will be irregularly distributed.
The state of coupling with the deflection magnetic field also varies.

Therefore, various symptoms that cannot be associated with the deflection yoke alone, such as variations in peripheral resolution and occurrence of parallelogram distortion, occur, which worsens the actual evaluation.

There are very few differences in focus coils that can be determined by looking at them with the naked eye, and in most cases, the only way to judge them is to rely on actual operation.

Therefore, in order to obtain a focusing coil with particularly uniform peripheral resolution, conventional methods have been limited to sampling or using extremely high-precision materials and parts, which has the disadvantage of not being suitable for mass production and being extremely expensive. there were.

The present invention has been made to eliminate the above-mentioned drawbacks, and includes forming grooves at a constant pitch in the circumferential direction in the winding part (including the winding jig) of the bobbin, and The present invention provides a bobbin for a focus coil in which winding transition portions having a constant width along the axial direction and in which the groove is not formed are formed at at least l locations.

An embodiment of the present invention will be described in detail below.

FIG. 3 shows an embodiment of a focus coil bobbin according to the present invention, and in the figure, reference numeral 10 denotes a winding portion of the bobbin 2 (
This shows grooves formed at a constant pitch in the circumferential direction on the cylindrical part.

Although the groove 10 is formed in a large size (semicircular shape) in the illustrated example, it may have any shape as long as it can guide the copper wire.

A winding transition portion 11 in which a groove of a constant width along the axis is not formed is formed in the winding winding portion.

``This winding transition portion 11 is formed into a smooth planar shape, and may be formed at multiple locations instead of at one location.

The pitch P of the grooves 10 may be the maximum outer diameter of the winding wire, but if the maximum outer diameter is selected, the flange 1 and the copper wire will collide with each other at both ends of the bobbin during the winding, and the repulsion will cause the winding to start from a position skipped by one pitch. It has been confirmed that some defects occur.

Therefore, it is necessary to set the pitch to be larger than the maximum outer diameter of the winding by a gap commensurate with the winding property.

As a result of the test, good results were obtained when the pitch was about 5% larger than the maximum outer diameter.

For the bobbin 2 having such a configuration, the copper wire is first passed through the winding transition section 1.
Start winding from 1, and after winding one turn along the groove, wrap around the transition part 1.
1, the groove is made to cross the adjacent groove at a predetermined angle θ, and this process is repeated thereafter.

In this way, the winding end point of the first layer is at the winding transition part 1.
Becomes 1.

In other words, the end point of the first layer becomes the start point of the second layer.

Similarly to the first layer winding, the second layer winding is also wound by passing it over to the adjacent one at a predetermined angle θ only at the winding transition portion 11.

Thereafter, each layer is wound in the same manner.

The accuracy of matching the winding end point of each layer with the winding start point of the next layer varies depending on the tension and speed, but it is easier to match the winding end point of each layer with the winding start point of the next layer by increasing the transition angle θ of the transition part, and the winding of the bobbin axis direction component is easier to match. Since the distribution of components can also be narrowed, it is possible to create a focus coil with less variation.

Figure 4 shows the winding state of the focus coil using the bobbin of the present invention when the copper wire has the maximum outer diameter, and Figure 5 shows the winding state of the focus coil when the copper wire has the minimum outer diameter. Indicates the condition.

In this way, according to the present invention, the winding crossover portion of each layer is
Because the copper wire diameter can be concentrated in one place,
It is possible to completely prevent winding disturbances due to dimensional variations in the bobbin winding width.

Also, unlike conventional focus coils, the difference in the circumferential distribution of the windings can be limited to just one crossing point.
A high-precision electromagnetic focusing system can be obtained without adjustment.

Therefore, there is a significant advantage that high precision focusing coils can be manufactured in large quantities and at low cost.

Furthermore, there is no need for an expensive winding machine with high feeding accuracy, and the performance is stable, making it possible to use completely automatic winding.

It goes without saying that the above-mentioned embodiment shows only one example of the present invention, and various changes can be made as necessary.

For example, if a protrusion is provided that fills a substantially delta-shaped gap that occurs at the winding transition portions at both ends of the bobbin, the winding transition angle can be kept more constant.

Moreover, the winding portion of the bobbin does not have to be cylindrical.

As mentioned above, according to the present invention, it is possible to provide a focus coil that is regularly wound at a constant pitch, so that the inductance and capacitance are regularly distributed within the coil, and the coupling state with the deflection magnetic field is extremely good. .

Therefore, if the present invention is applied to an electromagnetic focusing type imaging device, an imaging device with uniform peripheral resolution can be manufactured at low cost, and the effect is remarkable.

[Brief explanation of the drawing]

Fig. 1 is a schematic plan view showing an example of a conventional focus coil, Fig. 2 is an explanatory diagram showing an ideal winding state of the focus coil, and Fig. 3 shows an embodiment of a bobbin for a focus coil according to the present invention. The plan view, Figures 4 and 5 are
FIG. 6 is an explanatory diagram showing the winding state of a focus coil using the bobbin shown in the figure. 1: Bobbin flange, 2: Bobbin, line, 10: Bobbin groove, 11: Line crossing section. 3: Winding the folded bobbin

Claims (1)

[Scope of utility model registration request] Grooves are formed in the winding part at a constant pitch in the circumferential direction, and at least one winding transition part is formed in the winding part in which no groove is formed with a constant width along the axial direction. A bobbin for focusing coils for image pickup tubes.