JPH0550193B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a positive temperature coefficient thermistor device for degaussing used in degaussing circuits of cathode ray tubes in color televisions, computer monitor displays, and the like.

(Prior Art) Demagnetization of a cathode ray tube is completed within a few seconds after the degaussing circuit starts being energized. If current continues to flow through the degaussing coil after degaussing is completed, it not only results in a loss of power consumption, but also causes an unnecessary magnetic field to remain, causing disturbances in the image on the cathode ray tube.

Conventionally, positive characteristic thermi devices for degaussing used in degaussing circuits of cathode ray tubes include those described in Japanese Utility Model Application Publication No. 57562/1982 and Japanese Patent Application Laid-open No. 34288/1988.

In all of the conventional examples described above, a control PTC thermistor and a heating PTC thermistor are thermally coupled, and first, the control PTC thermistor reduces the current flowing through the demagnetizing coil, and then the heating PTC thermistor is connected to the heating PTC thermistor. This was an attempt to increase the demagnetization effect by heating the control positive temperature coefficient thermistor to increase its resistance value.

(Problems with the Prior Art) However, in the conventional PTC thermistor device for demagnetization described above, even if the resistance value of the PTC thermistor for control increases due to heating by the PTC thermistor for heating, the PTC thermistor for control It is not an insulator, and a small amount of current continues to flow to the degaussing coil. This current leaves an unnecessary magnetic field in the degaussing coil, disturbing the image on the cathode ray tube. This is also a loss in power consumption.

Furthermore, in order to increase the resistance value of the control PTC thermistor as much as possible and limit the current flowing through the degaussing coil as much as possible, a large PTC thermistor that generates a large amount of heat is used as the heating PTC thermistor. Therefore, in order to prevent the heat of the heating PTC thermistor from having an adverse effect on the circuit function, a PTC thermistor for heating and a PTC thermistor for control must be thermally coupled and enclosed in a heat insulating case, or there may be restrictions on placement. Something happened.

Therefore, the present invention completely shuts off the current to the degaussing coil within a few seconds after the start of energization, eliminates the residual residual magnetic field, and allows the use of a smaller positive temperature coefficient thermistor for heating than conventional ones, which is useful for color televisions and computers. It is an object of the present invention to provide a degaussing positive temperature coefficient thermistor device used in a degaussing circuit of a cathode ray tube such as a monitor display.

(Means for Solving the Problems) The demagnetizing positive temperature coefficient thermistor device of the present invention employs the following configuration in order to solve the above-mentioned problems.

That is, the first accommodating part 9, the second accommodating part 10, and the third accommodating part 11 are divided by the locking piece 2 formed on the inner wall surface of the case 1, and the heat stored in the second accommodating part 10 is separated. The control positive temperature coefficient thermistor 3 is housed in the first housing part 9 via the responsive body 5, and the heating positive temperature coefficient thermistor 4 is housed in the third housing part 11.
is pressed and held between the first spring terminal and the locking piece 2 by the spring property of the first spring terminal 6, and the heating positive temperature coefficient thermistor 4 is installed on the second spring terminal 7 and the locking piece 2 side. One side of the thermally responsive body 5 is fixed to the terminal 8, and the other side is fixed to the control positive temperature coefficient thermistor 3 at room temperature. It is characterized in that, after the start of energization, it is deformed by the heat of the heating PTC thermistor 4 and moves away from the control PTC thermistor 3.

(Example) Hereinafter, an example of the positive temperature coefficient thermistor device for demagnetization of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a side sectional view showing a positive temperature coefficient thermistor device for demagnetization according to the present invention.

First, 1 is a case, and 2 protruding toward the center of the case 1 are provided on opposing inner wall surfaces, respectively.
It has a total of four locking pieces 2. and,
The inside of this case 1 is divided by a locking piece 2 into a first accommodating part 9, a second accommodating part 10, and a third accommodating part 11. Further, a first spring terminal 6 is installed on one side of a pair of opposing inner wall surfaces parallel to this locking piece 2 of the case 1, and a second spring terminal 7 is installed on the other side. is installed. One end a of the first spring terminal 6 and one end c of the second spring terminal 7 are
Each is derived outside Case 1. Also, 4
Terminals 8 are installed on two opposing locking pieces 2 on the side closer to the surface on which the second spring terminal 7 is installed. One end b of the spring terminal 8 is led out of the case 1. Reference numeral 3 denotes a positive characteristic thermistor for control, which is held pressed between the first spring terminal 6 and the locking piece 2 by the spring property of the first spring terminal 6, and is connected to one electrode of the positive characteristic thermistor 3 for control. It is electrically connected to the spring 6. Reference numeral 4 denotes a positive temperature characteristic thermistor for heating, which is pressed and held between a terminal 8 installed on the locking piece 2 side and a second spring terminal 7 by the spring property of the second spring terminal 7, and has a positive temperature characteristic thermistor for heating. One electrode of the thermistor 4 is electrically connected to the terminal 8, and the other electrode and the spring terminal 7 are electrically connected. 5 is a V-shaped heat-responsive body such as bimetal, one side of which is fixed to the terminal 8 by spot welding, and is electrically connected to the terminal 8.
The other side is connected to the electrode of the control positive temperature coefficient thermistor 3 at room temperature, and conduction is established between the terminal 8 and the control positive temperature coefficient thermistor 3. When heated by the thermistor 4, it deforms and separates from the electrode of the control PTC thermistor 3, completely blocking the current between the terminal 8 and the control PTC thermistor 3.

It should be noted that the above-described embodiment is one embodiment of the present invention, and the present invention is not limited thereto, and it goes without saying that design changes can be made within a range that does not impair the significance of the present invention. Especially regarding the thermally responsive body 5,
A shape memory alloy or the like may be used instead of bimetal, and the shape is not limited to the V-shape. Furthermore, the shape of the locking pieces 2 is also arbitrary, and is limited to one in which two locking pieces 2 are respectively protruded toward the center of the case 1 from the opposing inner wall surfaces, as in this one structural example. It's not something you can do.

FIG. 2 is a circuit diagram showing a degaussing circuit in which the positive temperature coefficient thermistor device for degaussing of the present invention is used. First, PTC3 is a control positive temperature coefficient thermistor,
Together with the degaussing coil L, it forms a series circuit and is connected to both ends of the power supply E. PTC4 is a positive temperature coefficient thermistor for heating, and a positive coefficient thermistor for control.
It is connected in parallel with the series circuit of PTC3 and degaussing coil L. 5 is a thermally responsive body, which is thermally coupled to a heating positive temperature coefficient thermistor PTC4,
Control positive temperature coefficient thermistor PTC3 and degaussing coil L
connected in series with the series circuit. a′、b′、
c' is one end a of the first spring terminal 6 shown in FIG.
One end b of the terminal 8 corresponds to one end c of the second spring terminal 7, respectively. Figure 3 shows the control positive temperature coefficient thermistor PTC3 and the heating positive coefficient thermistor PTC4.
FIG. 3 is a diagram showing an example of the resistance temperature characteristics of. for example,
Here, the Curie temperature of the PTC thermistor for control is set to 50℃, and the PTC thermistor for heating is set to 50℃.
The Curie temperature of PTC4 is set to 80℃.
The heating PTC thermistor PTC4 of the PTC thermistor device for demagnetization used in this demagnetization circuit is designed to heat and deform the thermally responsive body 5, so the Curie temperature is set lower than that used in conventional demagnetization circuits. can do.

To specifically explain the degaussing circuit shown in FIG. 2, first, for example, about 5 seconds after the start of energization to the degaussing circuit, the control positive temperature coefficient thermistor PTC3 increases its resistance value, and the current to the degaussing coil L increases. Demagnetization is performed by limiting the Control positive temperature coefficient thermistor PTC3
While the resistance value of the heating PTC thermistor PTC4 increases, current flows through the heating PTC thermistor PTC4 and generates heat, and within a certain period of time, the heating PTC thermistor PTC4 also reaches a stable operating point. The thermally responsive body 5 is heated by the heating PTC thermistor PTC4, deforms, and cuts off the current to the series circuit of the control PTC thermistor PTC3 and the degaussing coil L. As a result, after the demagnetization is completed, no current flows through the demagnetization coil L at all.

(Effects of the Invention) The positive temperature coefficient thermistor device for demagnetization of the present invention configured as described above is configured such that after the resistance value of the control positive temperature coefficient thermistor increases and the current to the demagnetizing coil is limited to complete demagnetization. The thermally responsive body heated and deformed by the heating PTC thermistor completely cuts off the current to the degaussing coil, so no unnecessary magnetic field remains after degaussing is completed, and the image on the cathode ray tube does not become distorted. .

Moreover, after the current to the degaussing coil is cut off, the power consumption of the degaussing circuit can be limited to the consumption of the positive temperature coefficient thermistor for heating, so power loss can be reduced. Furthermore, the purpose of the heating PTC thermistor used in the degaussing circuit is not to heat the control PTC thermistor to increase its resistance value as in the past, but to heat and deform the thermally responsive body, so it is not very large. Since a compact device that does not require heat generation and consumes little power can be used, power consumption can be further reduced.

Furthermore, in the PTC thermistor device for demagnetization of the present invention, the heat generated by the PTC thermistor for heating can be made smaller than the heat generated by the PTC thermistor for heating used in the conventional PTC thermistor device for demagnetization. , the heat-resistant design of each component that makes up the degaussing circuit is easy. In addition, since the positive temperature coefficient thermistor device for degaussing of the present invention does not adversely affect other circuit functions due to heat, it can be placed in color televisions, computer monitor displays, etc. like conventional degaussing circuits. is not subject to any restrictions.

In addition, the time when the control PTC thermistor of the PTC thermistor device for degaussing of the present invention is energized is only for a few seconds after the start of energization to the degaussing circuit, and during the operation of a television, a computer monitor display, etc. This is much shorter than the energization time of a control positive temperature coefficient thermistor used in a conventional degaussing circuit that continues to energize. Therefore, the control PTC thermistor used in the demagnetizing PTC thermistor device of the present invention has a longer life than the control PTC thermistor used in the conventional demagnetizing PTC thermistor device.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing an embodiment of the PTC thermistor device for demagnetization of the present invention, FIG. 2 is a circuit diagram showing a degaussing circuit in which the PTC thermistor device for demagnetization of the present invention is used, and FIG. is the resistance temperature characteristic of the control PTC thermistor device and the heating PTC thermistor. 3...Positive temperature coefficient thermistor for control, 4...Positive temperature coefficient thermistor for heating, 5...Thermo-responsive body.

Claims (1)

[Claims] 1 A first accommodating part 9, a second accommodating part 10, and a third accommodating part 11 are divided by a locking piece 2 formed on the inner wall surface of the case 1. The control positive temperature coefficient thermistor 3 is housed in the first housing part 9 via the body 5, and the third
A heating positive temperature coefficient thermistor 4 is housed in the housing portion 11, and the control positive temperature coefficient thermistor 3 is held pressed between the first spring terminal and the locking piece 2 by the springiness of the first spring terminal 6. The heating PTC thermistor 4 is held pressed between the second spring terminal 7 and a terminal 8 installed on the locking piece 2 side by the spring property of the second spring terminal 7, and the thermally responsive body 5 has one side fixed to the terminal 8, and the other side contacts the control PTC thermistor 3 at room temperature, and after energization starts, is deformed by the heat of the heating PTC thermistor 4 and separates from the control PTC thermistor 3. 1. A positive characteristic thermistor device for demagnetization, which operates as follows.