JPH0316394A - Cathode ray tube device - Google Patents

Abstract

PURPOSE:To suppress leakage magnetic flux generated from a deflection yoke uniformly in all spaces around a cathode ray tube without losing the deflection characteristic of the cathode ray tube by arranging a leakage magnetic flux compensation coil reducing the leakage magnetic flux at the peripheral part of the cathode ray tube. CONSTITUTION:When a leakage magnetic flux compensation coil 28 is arranged to a passing region of a leakage magnetic flux generated from a part leading to a front face of a horizontal deflection main coil so that the part of the leakage magnetic flux compensation coil is placed in the vicinity of the part leading to the front face of the horizontal deflection main coil, an induced electromotive force is induced in the leakage magnetic flux compensation coil 28 due to a timewise change in the leakage magnetic flux generated from the part leading to the front face of the horizontal deflection main deflection coil and an induction current flows. Thus, a magnetic flux 37 in the opposite direction to the leakage magnetic flux 10 is generated. Then the leakage magnetic flux of the surrounding of the cathode ray tube is reduced.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a cathode ray tube device configured to reduce leakage magnetic flux generated from a deflection yoke (prior art). For example, from the perspective of radio wave interference,
VDE (Verband Deutcher)
Eloktrotechnlker) and others have established standards and regulations, and in the field of cathode ray tubes, regulations are generally based on VDE.

By the way, as a recent trend, there is a movement mainly in Northern Europe to regulate leakage magnetic fields, mainly focusing on the effects on the human body.

According to the MPR (S81) standard, a magnetic field of 1 kHz to 41) kHz is a problem, and for cathode ray tube devices, out of the magnetic flux generated from the horizontal deflection coil of the deflection yoke, electrons emitted from the electron gun It is necessary to reduce the magnetic flux in the portion that does not contribute to beam deflection, that is, the leakage magnetic flux, to a considerable level.

However, as a means for suppressing leakage magnetic flux in this cathode ray tube device, it is necessary to attenuate the leakage magnetic flux to a predetermined level, but at the same time, it must be done so as not to affect the main magnetic flux that deflects the electron beam. It is necessary to not change the deflection characteristics related to convergence, landing, etc.

FIG. 15 shows a general deflection yoke attached to a cathode ray tube such as a color picture tube. This deflection yoke has a horizontal axis (X
are placed across the axis).

In this deflection yoke, most of the magnetic flux generated from the horizontal deflection main coil (2) is confined in the inner space of the deflection yoke by the core (3) surrounding the outer circumferential side of the molded member (1), but some of it is , is radiated to the outside as leakage magnetic flux. FIG. 16 shows the leakage state of the horizontal deflection magnetic field formed by the horizontal deflection main coil (2). Normally, the leakage magnetic flux (7〉) of the horizontal deflection main magnetic flux (Is) is expressed by the curve (8a)
, (8b) with an opening angle of 30 to 40'', and above and below the front transition section (2) of the horizontal deflection main coil (2).
9) to the leakage magnetic flux (lO
) is occurring.

Conventionally, there is a method of covering the entire deflection yoke with a metal plate as a means of suppressing leakage magnetic flux around the cathode ray tube, but simply covering the deflection yoke with a metal plate is insufficient for shielding, and the leakage magnetic flux cannot be suppressed. It cannot be reduced to the desired level. In addition, such a suppression means not only shields leakage magnetic flux, but also has a structure that covers the entire deflection yoke.
There are also problems with heat dissipation and cost due to structural design constraints.

As a means to solve the above-mentioned problem of suppression by the metal plate, Japanese Patent Application Laid-Open No. 62-84024 discloses that the force of the saddle-shaped horizontal deflection main coil (2) and the core (
An auxiliary coil (1L) with almost the same shape as the horizontal deflection main coil (2) is placed across the horizontal deflection main coil (2), and the direction of the main magnetic flux of the horizontal deflection main coil (2) is opposite to that shown by the arrow (12). A part of the current flowing through the horizontal deflection main coil (2) is passed in the opposite phase so that the magnetic flux in the direction shown by the arrow (i3) passes through, thereby reducing the leakage magnetic flux of the horizontal deflection main coil (2). What has been done is shown.

However, with this method using the auxiliary coil (11), it is difficult to control the leakage magnetic flux at a predetermined position to be attenuated to a predetermined level. If the correction is too strong, it tends to have the opposite effect. Furthermore, the use of a coil that generates such reverse magnetic flux near the deflection yoke
It also tends to affect the deflection characteristics described above.

(Issue 8 to be solved by the invention) As mentioned above, conventionally, in order to reduce the leakage magnetic flux generated from the deflection yoke of a cathode ray tube device, a core is sandwiched between the outside of the saddle-shaped horizontal deflection main coil. There is a method in which an auxiliary coil having approximately the same shape as the coil is arranged, and a part of the current flowing through the horizontal deflection main coil is passed through the auxiliary coil in an opposite phase to reduce the leakage magnetic flux of the horizontal deflection main coil.

However, with this suppression method using an auxiliary coil, it is difficult to control the leakage magnetic flux at a predetermined position to be attenuated to a predetermined level, and the correction is too severe for the rear part of the deflection yoke, which tends to have the opposite effect.

Furthermore, there is a problem that it tends to affect the deflection characteristics.

This invention was made in view of the above problems, and
To effectively reduce the leakage magnetic flux generated from the saddle-shaped horizontal deflection main coil of a deflection yoke for a cathode ray tube, and to prevent it from having much effect on the deflection characteristics related to over-correction, electron beam convergence, landing, etc. purpose.

[Aside from the Invention] (Means for Solving the Problem) In a cathode ray tube device in which a deflection yoke having a saddle-shaped horizontal deflection main coil is mounted on the outside, an electron beam emitted from an electron gun of the cathode ray tube is deflected. The above-mentioned magnetic flux is arranged so that a part of the leakage magnetic flux generated from the front transition part of the horizontal deflection main coil is located in the vicinity of the front transition part of the horizontal deflection main coil in the opposite direction to the main magnetic flux of the horizontal deflection main coil. Due to the induced electromotive force induced by capturing the leakage magnetic flux,
A leakage flux compensation coil was installed to reduce leakage magnetic flux around the cathode ray tube.

(Function) As mentioned above, the leakage magnetic flux compensation coil is arranged in the passage area of the leakage magnetic flux generated from the front transition section of the horizontal deflection main coil so that a part thereof is located near the front transition section of the horizontal deflection main coil. Then, an induced electromotive force is induced in the leakage magnetic flux compensation coil due to a temporal change in the leakage magnetic flux generated from the front transition portion of the horizontal deflection main coil, and an induced current flows. This generates a magnetic flux in the opposite direction to the leakage magnetic flux, making it possible to reduce the leakage magnetic flux around the cathode ray tube.

(Example) Hereinafter, the present invention will be described based on an example with reference to the drawings.

FIGS. 1 and 2 show a color picture tube device which is an embodiment of the present invention. The color picture tube of this device has an envelope (22) consisting of a substantially rectangular panel <20> and a funnel-shaped funnel (2l) that are joined together. A phosphor screen made of a color phosphor layer is provided, and a shadow mask is mounted inside the phosphor screen, facing the phosphor screen.

Further, an electron gun that emits three electron beams is installed in the neck (23) of the funnel (2l).The three electron beams emitted from the electron gun are deflected to this color picture tube. Therefore, a deflection yoke (25) is attached to the outside of the boundary between the cone (24) of the funnel (2l) and the neck (23).

This deflection yoke (25) is arranged vertically symmetrically across the horizontal axis inside the mold member (2B), and has a pair of saddle-shaped horizontal deflection main coils that form a magnetic field that deflects the three electron beams in the horizontal direction. For example, a pair of toroidal vertical deflection coils are wound around the core and arranged vertically symmetrically on the outside of the mold member (26) across the horizontal axis, and form a magnetic field that deflects the three electron beams in the vertical direction. Equipped with.

Furthermore, this color picture tube device has the above-mentioned funnel (
A short-loop leakage flux compensation coil (28>) wound at least once is arranged on the upper and lower outer surfaces of the cone part (24>) of the leakage flux compensation coil (21).
28> is such that its rear part is located above the front transition part (transition part on the phosphor screen side) of the saddle-shaped horizontal deflection main coil, and the front part is positioned so that the maximum diameter loop can be obtained for the color picture tube. Explosion-proof bands (29) are attached to the sides of each corner of the panel (20).
) surrounding each pair of lug plates (30) attached.

As mentioned above, when short-loop leakage flux compensation coils (28) are placed on the upper and lower outer surfaces of the cone (24) of the funnel (21) of the color picture tube, the leakage flux compensation coil (28) is caused by the magnetic flux passing through this part. ), and an induced current flows.That is, as shown in Fig. 3, the leakage flux compensation coil (28) compensates for the leakage flux (7) of the main magnetic flux (B) of the horizontal deflection main coil. It is located outside the curves (8a) and (8b) that indicate the range through which the main magnetic flux (6) passes from the front transition part of the horizontal deflection main coil.
Leakage magnetic flux (lO) in the opposite direction passes through. Therefore,
The magnetic flux (32) generated from the leakage flux compensation coil (28) due to the induced current is caused by the main magnetic flux (32) in front of the horizontal deflection main coil (
6) leakage magnetic flux (7〉), leakage magnetic flux compensation coil (2)
In the M region immediately below 8>, the direction is such that leakage of the main magnetic flux (6) is promoted. However, as the area moves farther away from a certain point A in the tube axis direction, the magnetic flux (32) generated from the leakage flux compensation coil (28) cancels out the leakage flux (7) around the color picture tube. It turns into

The above point A is approximately 10 to 20 cm from the front surface of the panel, although it varies depending on the size of the color picture tube, the type of deflection yoke, and how the leakage flux compensation coil (28) is applied.

This compensation effect reduces leakage magnetic flux (7〉) not only in the front of the color picture tube but also in all directions around the color picture tube.
can be obtained for. That is, regarding the color picture tube in which the leakage flux compensation coil (28) is arranged as described above, the Ml? Based on the P standard, the magnetic field distribution (leakage magnetic flux density) on a spherical surface with a radius of 65 cm surrounding the color picture tube is as shown in FIG. In this figure, the horizontal axis is the circumferential angle (Deg) and the vertical axis is the magnetic flux density (nT). is the case where a leakage flux compensation coil is arranged. Also, (a) .(
b). Each figure in (c) has an elevation angle of 0' and 2, respectively.
2.5", 4!).0" (7) Measurement results.

As can be seen from this measurement result, when the leakage flux compensation coil is placed, the leakage flux can be reduced by 50 to 60% compared to the case where no leakage flux compensation coil is placed, and it is possible to reduce the leakage flux by 50 to 60% compared to the case where no leakage flux compensation coil is placed. It can be made almost uniform in position. Moreover, it hardly affects the deflection characteristics related to convergence or landing of the color picture tube.

Next, another embodiment will be described with the same numbers assigned to the same parts as in the above embodiment.

FIG. 5 shows an example in which the rear part of the leakage flux compensating coil (28), which consists of a single loop, is located along the front transition portion of the horizontal deflection main coil of the deflection yoke (25).

When the leakage flux compensation coil (2B) is arranged in this way,
As shown in Fig. 6, the leakage magnetic flux (10) generated from the front connecting portion of the horizontal deflection main coil is stronger the closer it is to the connecting wire (3B). The magnetic flux (10) can be maximized. Therefore, the induced current induced in the leakage magnetic flux compensation coil (28) is large, and the generated compensation magnetic flux (37) can be strengthened.

Note that the leakage flux compensation coil (28) in this example also has its front part extended over the side surface of the panel (20);
This is to optimize the balance of the magnetic field in front and behind the color picture tube, and the strength of the magnetic field is determined by the length of the rear part of the leakage flux compensation coil (28) along the front transition section of the horizontal deflection main coil and the length of the rear part of the leakage flux compensation coil (28). In this example, the temporal change in leakage magnetic flux d B/d t at the measurement point of the MRP standard is adjusted by changing the loop area of 28〉.
．． was able to be reduced to 15ωT/s or less.

In FIG. 7, the rear part of the leakage magnetic flux compensation coil (28) is located along the front transition part of the horizontal deflection main coil of the deflection yoke (25>), and a A small loop portion (38) is provided which is wound more than once.

If the leakage flux compensation coil (28) is arranged so that the rear part is located at the front transition part of the horizontal deflection main coil and the small loop part (38> is provided at the rear part), the large loop part (39) By increasing the induced electromotive force, the compensation magnetic field by the leakage flux compensation coil (28) can be further strengthened.

FIG. 8 shows that the rear part of the leakage magnetic flux compensation coil (28) is located along the front transition part of the horizontal deflection main coil of the deflection yoke (25), and the deflection yoke (25) is located at the rear part of the coil. A small loop portion (38) is provided at the front transition portion and the rear transition portion of the horizontal deflection main coil to straddle the coil.

With this configuration, not only the leakage magnetic flux generated from the front transition section but also the leakage magnetic flux generated from the rear transition section can be linked to the small loop section (38). ), and the compensation magnetic field by the leakage flux compensation coil (28) can be further strengthened.

Figure 9 shows the arrangement of the deflection yoke (25) so that the rear part of the leakage flux compensation coil <28> is located along the front transition section of the horizontal deflection main coil, and a small loop is placed in the part on the panel (20) side. (38).

Generally, when the leakage magnetic flux F}Ii compensation coil (28) is arranged on the outer surface of the cone portion (24) of the funnel (21), the compensation magnetic field at the front of the color picture tube tends to be weaker than at the rear. Therefore, if the small loop portion (38) is provided on the panel (20) side portion as in this example, the compensation magnetic field in front of the color picture tube can be strengthened.

Figure 10 shows a panel (
It is arranged separately on the side surface of the deflection yoke (20) and on the front transition section of the horizontal deflection main coil of the deflection yoke (25), so that the compensation magnetic field is especially strong in front of the color picture tube.

In Fig. 1i, the rear part of the leakage flux compensation coil (28) is arranged along the front transition part of the horizontal deflection main coil of the deflection yoke (25), and the rear part of the leakage flux compensation coil (28) is adjacent to the deflection yoke (25)
An auxiliary coil (4l) is disposed outside of the horizontal deflection main coil, and part of the current flowing through the horizontal deflection main coil is passed through this auxiliary coil (4l).

Generally, the leakage flux compensation coil (28) is different from the auxiliary coil that flows the horizontal deflection current.
〉The magnetic field is generated by the induced electromotive force induced by the magnetic flux interlinked with the
Even if efforts are made to increase the interlinking magnetic flux as in the illustrated embodiment, there is a limit to the strength of the compensating magnetic field that can be obtained due to the increase in resistance and inductance that accompanies the complicated loop shape. Furthermore, in view of the manufacturing cost of the color picture tube device, it is preferable that the leakage magnetic flux compensation coil (28) has a shape as simple as possible.

From this point of view, if the auxiliary coil (4l) is placed adjacent to the rear of the leakage flux compensation coil (28) as in this example, as shown in FIG.
From the main magnetic flux (6〉) of the horizontal deflection main coil and the magnetic flux in the same direction (
42) occurs. This magnetic flux (42) is transmitted to a leakage magnetic flux compensation coil (28) at the front or rear of the color picture tube.
It is in the same direction as the compensating magnetic flux (37) generated from the leakage magnetic flux (37), and compensates for the effect of canceling out the leakage magnetic flux (7). Also, this magnetic flux (4l) is in the same direction as the leakage magnetic flux (10) generated from the front transition section of the horizontal deflection main coil, and is Il;ii?!4
Since it interlinks with the magnetic flux compensation coil (28), it strengthens the compensation magnetic field generated from the leakage magnetic flux compensation coil (28).

FIG. 13 shows the leakage flux compensation coil (28) with ε arranged so that the rear part of the leakage flux compensation coil (28) is located along the front transition portion of the horizontal deflection main coil of the deflection yoke (25). This is an example in which an auxiliary coil (41) similar to the embodiment shown in FIG. 11 is arranged adjacent to the side surface of the panel (2o).

In addition, Fig. 14 shows that the leakage magnetic flux compensation coil (28) is extended to the rear cross section of the horizontal deflection main coil of the deflection yoke (25), and is placed on the deflection yoke (25) so as to be inscribed in the extended section (4L). An auxiliary coil (4i) is arranged at the top.

In this case, the magnetic flux generated from the auxiliary coil (4l) is in the opposite direction to the leakage flux compensation coil (28) as shown in Figure 13, but it is in contact with the inside of the leakage flux compensation coil (28). Therefore, by arranging the auxiliary coil (41) in this way, the compensating magnetic field obtained from the leakage flux compensating coil (28) is interlinked in the direction of strengthening it. , it is possible to correct overcompensation at the rear of the color picture tube.

Although the embodiments of the color picture tube device have been described above, it goes without saying that the present invention can also be applied to cathode ray tubes other than color picture tubes.

[Effects of the Invention] The leakage magnetic flux generated from the front cross-section of the horizontal deflection main coil in the opposite direction to the main magnetic flux of the saddle-shaped horizontal deflection main coil of the deflection yoke that deflects the electron beam emitted from the electron gun of the cathode ray tube. A leakage magnetic flux that captures the leakage magnetic flux so that a portion thereof is located in the passing region near the front transition portion of the horizontal deflection main coil, thereby inducing an induced electromotive force to reduce the leakage magnetic flux in the peripheral area of the cathode ray tube. When the compensation coil is arranged, the induced electromotive force induced in the leakage magnetic flux compensation coil due to the leakage magnetic flux generated from the front transition section of the horizontal deflection main coil is reduced.
It is possible to generate a reverse magnetic flux that reduces the leakage magnetic flux, and the leakage flux generated from the deflection yoke can be uniformly suppressed in all spaces around the cathode ray tube without impairing the deflection characteristics of the cathode ray tube.

[Brief explanation of the drawing]

1 to 14 are explanatory diagrams of an embodiment of the present invention, in which FIG. 1 is a perspective view showing the configuration of a color picture tube device that is one embodiment, FIG. 2 is a plan view thereof, and FIG. is a diagram for explaining the action of the leakage flux compensation coil, FIGS. 4(a) to (c) are diagrams each showing the leakage flux reduction effect by the leakage flux compensation coil, and FIGS. 5(a) and (b) are respectively a plan view and a side view of other embodiments, FIG. 6 is a diagram for explaining the action of the leakage flux compensation coil, and (a) and (b) of FIGS. 7 to 11 are respectively different examples. FIG. 12 is a diagram for explaining the action of the leakage flux compensation coil of the embodiment shown in FIG. 1I, and FIGS. 13 and 14 (a) and (b) are ) are plan views and side views of other different embodiments, respectively;
Figure 15 is a perspective view of the deflection yoke attached to the color picture tube, Figure 16 is a diagram showing the magnetic flux generated from the horizontal deflection main coil of the deflection yoke shown in Figure i5, and Figure 17 is the conventional leakage magnetic flux. FIG. 3 is a configuration diagram of a deflection yoke equipped with an auxiliary coil that reduces the yoke. 7...Leakage magnetic flux of horizontal deflection main magnetic flux 10...Leakage magnetic flux 20...Panel 2...
Funnel 22...Envelope 23...Neck
24... Cone part 25... Deflection yoke
28... Leakage magnetic flux compensation coil 29... Explosion-proof band 30... Lug plate 37... Compensation magnetic flux 3
8...Small loop part 39...Large loop part 41.
... Auxiliary coil 42 ... Magnetic flux from the auxiliary coil

Claims (1)

[Claims] a cathode ray tube; a deflection yoke having a saddle-shaped horizontal deflection main coil attached to the outside of the cathode ray tube and horizontally deflecting an electron beam emitted from an electron gun of the cathode ray tube; It is arranged in a passing region of the leakage magnetic flux generated from the front transition portion of the horizontal deflection main coil in the opposite direction to the magnetic flux, and a portion thereof is located near the front transition portion of the horizontal deflection main coil to capture the leakage magnetic flux. A cathode ray tube device comprising: a leakage magnetic flux compensation coil that reduces leakage magnetic flux in a peripheral portion of the cathode ray tube by an induced electromotive force induced thereby.