JPH0727614Y2 - High voltage variable resistor block - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] This invention is used for, for example, a television or a CRT display, and is a high voltage used for focus voltage adjustment and screen voltage adjustment in a cathode ray tube (CRT) having a four-electrode structure. It relates to a variable resistor block.

[Background technology]

In recent years, a so-called four-electrode structure has been newly developed as an electron gun for this type of CRT.

FIG. 5 simply shows the principle, and the cathode 2
The electron beam 3 extracted from the four electrodes 4a-4d
The focus is adjusted in the two XY directions to improve the freshness around the screen.

[Problems to be solved by the invention]

The electron gun as described above needs to be supplied with two independent variable focus voltages VF ₁ and VF ₂ .

However, since the conventional high voltage variable resistor block has only one variable resistor for adjusting the focus voltage, it is not possible to deal with the new electron gun as described above, and the conventional high voltage variable resistor block cannot be used. Although it is possible to cope with this by using two blocks, if doing so, problems such as enlargement in space etc., extra high voltage wiring between each other, and cost increase will occur. .

Therefore, the main object of the present invention is to provide a high-voltage variable resistor block which can cope with the electron gun having the four-electrode structure as described above and which does not cause the problems described in (1) to (3) above.

[Means for solving problems]

The high-voltage variable resistor block of the present invention is for supplying a high voltage to a cathode-ray tube having a four-electrode structure, and has two variable resistors for adjusting the focus voltage in an insulating case in which an insulating substrate is arranged in the opening. A variable resistor for adjusting a resistor and a screen voltage is provided, and three ring-shaped film resistors that respectively constitute the variable resistors are formed on the insulating substrate, and on the insulating substrate. Two film resistors forming a variable resistor for focus voltage adjustment are electrically connected in parallel to each other, and a film resistor forming a variable resistor for screen voltage adjustment is electrically connected in series to them. Further, the opening of the insulating case and the outside of the insulating substrate are molded with an insulating resin.

〔Example〕

FIG. 1 shows a high voltage variable resistor block according to an embodiment of the present invention, (A) is a front view, (B) is a side view, and (C) is a rear view.

In the high voltage variable resistor block 5 of this embodiment, an insulating substrate 7 is arranged in the opening on the back side and an insulating case 6 covered with the insulating substrate 7 is used to adjust the focus voltages VF ₁ and VF ₂ described above, respectively. It has two variable resistors VR ₁ and VR ₂ and VR ₃ for adjusting the screen voltage.

More specifically, the insulating case 6 includes each variable resistor VR _{1 to} VR ₃
Rotating shafts 8a to 8c made of an insulating material are pierced so as to be rotatable by a predetermined angle. The penetrating portion is filled with silicone grease for lubrication and sealing.

The inside of the insulating case 6 is divided into three chambers by partitions 61 and 62 as shown in FIG. 2, for example. Reference numerals 81a to 81c are discs made of an insulating material and connected to the rotary shafts 8a to 8c, and 82a to 82c are recesses formed in them.

On the other hand, the insulating case inner major surface of the insulating substrate 7, for example, as shown in FIG. 3, the variable resistor VR ₁ to VR ₃ three ring-shaped film resistor respectively constituting 11 a to 11 c, and , A film resistor 11d for connecting them to a predetermined electric circuit (see FIG. 4) and a film conductor 1 shown by hatching
2 is formed.

Further, as shown in FIG. 1, pin terminals 9a to 9e are projectingly provided on the main surface of the insulating substrate 7 outside the insulating case,
A high voltage is applied to the pin terminals 9a to 9d among them, so that a sleeve 10 made of an insulating material is covered. Incidentally, 13a to 13e shown in FIG. 3 are solders for connecting the respective pin terminals 9a to 9e to the coated conductor 12, respectively.

Then, in the recesses 82a to 82c shown in FIG. 2, sliders (not shown) for connecting the respective film resistors 11a to 11c on the insulating substrate 7 and the film conductor 12 at the central portion are mounted. In addition, an adhesive is applied to the step-down portion 65 and the partitions 61 to 64 of the insulating case 6, and the insulating substrate 7 shown in FIG. The resistor block 5 is configured. After the insulating substrate 7 is covered, the opening of the insulating case 6 and the outer surface of the insulating substrate 7 (that is, the surface on the side of the pin terminals 9a to 9e) is molded with an insulating resin such as an epoxy resin. However, the illustration is omitted here.

An equivalent circuit of the high voltage variable resistor block 5 is shown in FIG. In this example, two variable resistors VR ₁ and VR ₂ for adjusting the focus voltage are electrically connected in parallel with each other through a fixed resistance component, and in this example, a variable resistor VR ₃ for adjusting the screen voltage is connected thereto. They are connected in series via a fixed resistance component, which is connected between the pin terminal 9a for supplying the input voltage HV and the pin terminal 9e for grounding.

Therefore, when the input voltage HV is supplied to the pin terminal 9a, the input voltage HV is appropriately divided and the focus voltage VF is applied from the pin terminals 9b and 9c connected to the sliders of the variable resistors VR ₁ and VR ₂ , respectively. ₁ and VF ₂ are output, respectively, and the screen voltage VS is output from the pin terminal 9d connected to the slider of the variable resistor VR ₃ .

Incidentally, 63 in FIG. 2 is a partition that surrounds the solder 13a portion in FIG. 3 for electrical insulation, and 64 is the solder in FIG.
It is a partition for partitioning the portion 13d and the coated conductor 12 adjacent thereto for electrical insulation. Further, 66 is a hole for removing the internal air that expands when the insulating substrate 6 is covered with the insulating substrate 7 and resin is molded thereon, and 67 is a recess for forming the passage of the air. By the way, this hole 66
Are sealed after molding.

As described above, according to the high-voltage variable resistor block 5,
Since two independent focus voltages VF ₁ and VF ₂ can be taken out, it is possible to correspond to a new electron gun having a four-electrode structure as shown in FIG. Moreover, the two variable resistors VR ₁ and VR ₂ for adjusting the focus voltage and the VR ₃ for adjusting the screen voltage are arranged in one insulating case 6.
Since the film resistors 11d and the film conductors 12 on the insulating substrate 7 are used to electrically connect the variable resistors to each other, unlike the case where a plurality of variable resistor blocks are used, Compact, no extra high-voltage wiring between blocks is required, and assembly work is simple. When wiring high-voltage wiring externally, consideration should be given not to cause discharge between the wiring and other parts. However, in the present invention, there is no need to do so, and the effects of (1) and (2) being cheaper can be obtained.

Further, by molding the insulating resin in the opening of the insulating case 6 as described above, when the high-voltage variable resistor block 5 is integrally attached to the flyback transformer case, a crack is generated in the insulating substrate 7 and the withstand voltage is increased. In case of independently using the high voltage variable resistor block 5 which can prevent the voltage drop, the pin terminals 9a to
The effect that the creeping distance between 9e can be lengthened to prevent discharge from occurring between the pin terminals 9a to 9e is obtained. Details of these effects are as follows.

That is, when the high-voltage variable resistor block 5 is integrally attached to the flyback transformer case, a resin is molded inside the flyback transformer case. However, since this resin is usually a hard resin, this resin is a high-voltage variable resistor. If the insulating substrate 7 of the resistor block 5 is directly touched, the insulating substrate 7 may be cracked due to stress caused by the difference in expansion and contraction degree between the resin and the insulating substrate 7. When cracks occur, the withstand voltage decreases. On the other hand, like the high voltage variable resistor block 5,
If an insulating resin is molded on the back surface side (the opening side of the insulating case 6) of the insulating substrate 7, more specifically, a resin that is more flexible than the resin molded in the flyback transformer case, The resin serves as a cushioning material and can prevent the insulating substrate 7 from being cracked, thereby preventing a decrease in withstand voltage. On the other hand, when the high-voltage variable resistor block 5 is used independently without being incorporated in the flyback transformer, discharge may occur along the surface of the insulating substrate 7 between the pin terminals 9a to 9e having a potential difference. However, when the insulating resin is molded in the opening of the insulating case 6 as described above, the creepage distance becomes long due to the presence of the molding resin and the sleeve 10 made of an insulating material, so that the discharge can be prevented. it can.

The variable resistors CR ₁ and VR ₂ are electrically connected to each other (this is via a resistance component) by appropriately selecting the locations where the film resistor 11d and the film conductor 12 are provided on the insulating substrate 7 and their patterns. It is also possible to adopt a circuit configuration different from that shown in FIG. 4 while taking the state of being connected in parallel (whether or not) and the state of connecting the variable resistor VR ₃ in series thereto. .

So, for example, the center voltage of variable resistors VR ₁ and VR ₂ is
It can also be matched or different.

In addition, the input voltage HV supplied to the pin terminal 9a can be taken either from the middle stage of the flyback transformer (not shown) or from the upper stage.

Further, a capacitor can be attached to the insulating substrate 7 as needed.

Also, the two ring-shaped film resistors 11a and 11b may be configured to be back to back.

Further, the pin terminals 9a to 9e and the sleeve 10 as in this example are not necessarily used for input / output and grounding, and other means may be used depending on the purpose.

[Effect of device]

As described above, according to the present invention, two independent focus voltages can be taken out, so that it is possible to correspond to an electron gun having a four-electrode structure. Moreover, in one block, two variable resistors for focus voltage adjustment are connected in parallel with each other, and a variable resistor for screen voltage adjustment is connected in series to this, so multiple variable resistor blocks can be connected. Unlike the case where it is used, it is small and compact, there is no need for extra high voltage wiring between blocks,
Assembling work becomes easy, when wiring the high-voltage wiring externally, it is necessary to consider not to generate discharge between the wiring and other parts, but in the present invention, there is no need to do so.
As a result of the above, it is possible to obtain a special effect that the cost is reduced.

Also, since the opening of the insulating case and the outside of the insulating substrate is molded with insulating resin, when the high-voltage variable resistor block of the present invention is integrally attached to the flyback transformer case, cracks may occur in the insulating substrate. In case of independently using the high voltage variable resistor block of the present invention which can prevent the breakdown voltage from decreasing, the creepage distance between the pin terminals having the potential difference is lengthened to cause the discharge between the pin terminals. It is possible to obtain the special effect of being able to prevent this.

[Brief description of drawings]

FIG. 1 shows a high voltage variable resistor block according to an embodiment of the present invention, (A) is a front view, (B) is a side view, and (C) is a rear view. FIG. 2 is a front view showing the inside of the insulating case of FIG. FIG. 3 is a front view showing the inside of the insulating case of the insulating substrate of FIG. FIG. 4 is an equivalent circuit diagram of the high voltage variable resistor block of FIG. FIG. 5 is a diagram showing the principle of a four-electrode structure electron gun. 5 ... High-voltage variable resistor block according to the embodiment, 6 ... Insulating case, 7 ... Insulating substrate, 8a-8c ... Rotating shaft, 11a-1
1d ...... film resistor, 12 ...... film conductor, VR _1, VR ₂ ...... focus voltage variable resistor for adjusting, VR ₃ ...... screen voltage variable resistor for adjustment.

Claims (1)

[Scope of utility model registration request] 1. A high voltage for a cathode ray tube having a four-electrode structure, comprising two variable resistors for adjusting a focus voltage and a screen voltage in an insulating case having an insulating substrate arranged in an opening. Having a variable resistor for adjustment, three ring-shaped film resistors that respectively configure each of the variable resistors are formed on the insulating substrate,
Two film resistors forming a variable resistor for focus voltage adjustment are electrically connected in parallel on the insulating substrate, and a film resistor forming a variable resistor for screen voltage adjustment is connected to them. A high-voltage variable resistor block, which is electrically connected in series and further has an opening of the insulating case and an outer side of the insulating substrate molded with an insulating resin.