JP2507539B2 - Self-temperature control ribbon heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is used, for example, when a fluorescent discharge tube for illuminating a liquid crystal display device is heated at a low temperature and the like, and a resin material is mixed with certain components. The present invention relates to a self-temperature control type ribbon heater having a heating element obtained by.

[Conventional technology]

2 (a) and 2 (b) show a conventional self-temperature control type ribbon heater 1, 2 is a flat-shaped heating element having self-temperature controllability, 3 and 4 are in the heating element 2 in the longitudinal direction thereof. A parallel conductor wire 5 embedded along the heating element 2 is an insulating tube covering the heating element 2 and the parallel conductor wires 3 and 4. The parallel conductors 3 and 4 are drawn to the outside to energize the heating element 2 to form external leads 6 and 7. The heating element 2 and the insulating tube 5 have substantially the same length. As the insulating tube 5, for example, a Teflon tube is used. Reference numerals 8 and 9 are insulating coatings covering the external leads 6 and 7.

Next, the operation will be described. In general, a liquid crystal display element (hereinafter abbreviated as LCD) does not emit light, so that illumination from behind the element is necessary depending on external light conditions. Therefore, a highly efficient, high-brightness thin back lighting that does not impair the energy saving and thinness of the LCD (hereinafter abbreviated as backlight).
Development was awaited. As an example of this type of backlight, "Technical Report of the Television Society of Japan" IPD 105-2 (Showa 61)
It was published on February 25, 2002, but this backlight uses a fluorescent discharge tube as the light source. Therefore, when the temperature is low, the brightness of the discharge tube is lowered or the discharge tube is hardly lit at all due to a decrease in the mercury vapor pressure in the enclosure. For example, when the ambient temperature drops below -10 ° C, the discharge tube does not light up normally. Therefore, in order to ensure the normal operation of the discharge tube, it is first considered that the discharge tube is heated at a low temperature, and the heater 1 shown in FIG. 2 is used in such a case.

FIGS. 3 (a) and 3 (b) show an example of using the heater 1. When a predetermined voltage is applied between the parallel conductors 3 and 4 from the external power source through the external leads 6 and 7, the ambient temperature becomes below the predetermined value. When the temperature drops, heating is performed by the heating element 2, and the normal lighting operation of the fluorescent discharge tube 10 can be ensured. As this kind of heater, there was F. heater mini (trade name, manufactured by Fujikura Electric Cable Co., Ltd.).

FIGS. 4 and 5 show another conventional self-temperature control type ribbon heater 11 and an example of use thereof, in which insulating coatings 8 and 9 are not provided, and other configurations are the same as those of the ribbon heater 1.

[Problems to be Solved by the Invention]

Since the conventional heater has a shape in which the heating element 2 and the insulating tube 5 have substantially the same length, both end surfaces of the heating element 2 are exposed to the outside air. Therefore, the durability of the heater is practically problematic, and the heater is particularly vulnerable to moisture, so that the heater output is lowered and the self-temperature control function is lowered due to the moisture absorption of the heating element 2. As a countermeasure, the length of the insulating tube 5 may be made longer than the length of the heating element 2 and both ends thereof may be sealed. However, the material of the insulating tube 5 is Teflon, which is inexpensive due to a bonding method, a fusion bonding method, or the like. It was impossible to make a tight seal.

On the other hand, a method of covering both end faces of the heater 1 with a resin cap is also conceivable. An example of use in this case is shown in FIGS. 6 and 7. Reference numerals 12 and 13 are resin caps that cover both end surfaces of the heater 1. In this case, when the heaters 1 and 11 are placed along the fluorescent discharge tube 10, the heaters 1 and 11 are as much as the resin thickness of the resin caps 12 and 13.
Will be installed away from the fluorescent discharge tube 10. As a result, there arises a problem that the heating efficiency is reduced.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a self-temperature control ribbon heater capable of improving moisture resistance without lowering heating efficiency.

[Means for solving the problem]

In the self-temperature control type ribbon heater according to the present invention, both ends of an insulating coating such as an insulating tube are projected from both ends of a heating element, and an insulating resin is filled in the protruding portion or the protruding portion is covered by the insulating coating itself. It is fused and sealed.

[Action]

In the present invention, both ends of the insulating coating such as the insulating tube are sealed with the insulating resin or the insulating coating itself. Further, the shape of the heater is defined by the outer diameter of the insulating tube or the insulating coating, and the heater can be placed in contact with the fluorescent discharge tube.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. 1 (a) and 1 (b) show a first embodiment of the present invention,
Reference numeral 14 is a self-temperature control type ribbon heater, 15 is a flat-shaped heating element having self-temperature controllability, 16 and 17 are parallel conductive wires embedded in the heating element 15 in parallel with its length direction, and 18 is a heating element 15 Is an insulating tube that is coated around and has both ends projecting from both ends of the heating element 15. Reference numerals 19 and 20 denote external leads formed by projecting one ends of the parallel conductors 16 and 17 from one end of the heating element 15. Reference numerals 21 and 22 denote insulating coatings coated on the external leads 19 and 20. Reference numerals 23 and 24 denote insulating resins filled inside the portion of the insulating tube 18 protruding from the heating element 15. Insulating resin 23,2
Silicon resin such as one-component RTV rubber is used for 4. This resin has excellent heat resistance and becomes a rubber elastic body after curing, and since the insulating resin is filled in an insulating tube having a cross section of a substantially constant shape, the heater 14 is insulated at the end while maintaining the constant shape. . Therefore, there is no step between the heating element 15 and the insulating resins 23, 24 that has been generated on the surface of the conventional heater 14, and when the heater 14 is installed along a glass tube such as the fluorescent discharge tube 10, the discharge tube is not used. Can be installed in contact with 10 surfaces.

Next, the operation will be described. As in the conventional case, the heater 14 is heated along the fluorescent discharge tube 10 as shown in FIG. That is, when a predetermined voltage is applied between the parallel power lines 16 and 17 from the external power source through the external leads 19 and 20, heating is performed by the heating element 15 when the ambient temperature is equal to or lower than a certain temperature, and the fluorescent discharge tube. It is possible to secure 10 normal lighting operations. Moreover, since both ends of the heating element 15 are sealed by the insulating resins 23 and 24, the heating element 15 is not exposed and the heating element 15 is not exposed.
The output of the heater 14 and the self-temperature control function do not deteriorate due to the absorption of moisture. The length L of the insulating resin 23, 24 is effective if it is 1 mm or more, but it needs to be about 10 mm depending on the application.

Although the lengths L of the insulating resins 23 and 24 are the same in the above embodiment, they may not be the same. Further, in the ribbon heater 25 of the second embodiment shown in FIG. 9, a part of the insulating coatings 21 and 22 is embedded in the insulating resin 24. In this case, the length L may be embedded.

FIG. 10 shows a third embodiment of the present invention, in which 26 is a ribbon heater, 27 is a flat heating element having self-temperature controllability, 2
Reference numerals 8 and 29 denote parallel conductive wires provided in parallel in the heating element 27, and 30 denotes an insulating coating (including a coating) coated around the heating element 27. Both ends of the insulating coating 30 project from the heating element 27. There is. Reference numerals 31 and 32 are external leads formed by projecting one ends of the parallel conducting wires 28 and 29 from the heating element 27. Polysulfone is used as the insulating coating 30, and both ends thereof are sealed to form sealed portions 33 and 34. The heat-resistant temperature of polysulfone is inferior to that of Teflon at about 150 ° C, but the maximum temperature when the heating element 27 generates heat is 1
Since it is 35 ° C, there is no problem in practical use. The sealing may be performed by a fusion bonding method, for example, by wetting both ends of the insulating coating 30 with methylene chloride and bonding. Alternatively, they may be fused by heating or application of ultrasonic waves.

Next, the operation will be described. As in the prior art, as shown in FIG. 11, the heater 26 is placed along the fluorescent discharge tube 10 to heat it. The self-temperature control function is the same as that described above, and the sealed part made of an insulating coating does not become larger than the outer shape of the heating element as in the conventional case. As shown in FIG. 11, since it is smaller than the cross-sectional shape of the heating element, the portion of the heater 26 that particularly contributes to heating can be placed in contact with the fluorescent discharge tube 10. The length L of the sealing portions 33, 34 is effective if it is 0.1 mm or more, but it is necessary to set it to about 10 mm depending on the application.

Although the sealing parts 33 and 34 are sealed by fusion in the above-described embodiment, they may be bonded by using, for example, BR-92 (trade name, manufactured by American Cyanamide Co., Ltd.) as an adhesive. The heat-resistant temperature of BR-92 is 149 ℃, so no problem occurs. Insulation coating 30
Although polysulfone was used for this, polyether sulfone having a higher heat resistant temperature than this may be used.

〔The invention's effect〕

As described above, according to the present invention, since both ends of the insulating tube or the insulating coating whose both ends are longer than the heating element are filled with the insulating resin or sealed by the insulating coating itself, the moisture resistance is improved. Performance is improved, and deterioration of heater output and self-temperature control function is prevented. Even if both ends of the heating element are sealed, the shape of the heater is defined by the outer diameter of the insulating tube or the insulating coating, and the heater diameter does not unnecessarily increase, and the heater can be contacted with the fluorescent discharge tube or the like. It can be arranged and the heating efficiency is not reduced.

[Brief description of drawings]

1 (a) and 1 (b) are a cross-sectional plan view and a side view of a heater according to a first embodiment of the present invention, and FIGS. 2 (a) and 2 (b).
Is a cross-sectional plan view and side view of the conventional heater, FIGS. 3 (a) and 3 (b) are perspective views and front views of the conventional heater in use, and FIGS. 4 (a) and 4 (b) are conventional views. Cross sectional plan views and side views of other heaters, FIGS. 5 (a) and 5 (b) are perspective views and front views of other conventional heaters in use, and FIGS. 6 and 7 show conventional heaters. FIGS. 8A and 8B are perspective views and front views of the heater according to the first embodiment of the present invention when used with a resin cap, and FIG. 9A and FIG. (a) and (b) are cross-sectional plan views and side views of the heater according to the second embodiment of the present invention, and FIGS. 10 (a) and (b) are cross-sectional plan views of the heater according to the third embodiment of the present invention. FIG. 11 (a) and FIG. 11 (b) are a side view and a perspective view and a front view of the heater according to the third embodiment of the present invention in a use state. 14,25,26 …… Heater, 15,27 …… Heating element, 16,17,28,29…
… Parallel conductor, 18 …… insulation tube, 19,20,31,32 …… external lead, 23,24 …… insulating resin, 30 …… insulation coating, 33,
34 …… Sealed part. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (2)

(57) [Claims] 1. A heater for heating a fluorescent discharge tube, comprising: a flat heating element having self-temperature controllability; a plurality of parallel conductive wires arranged in the heating element in a longitudinal direction thereof; An external lead formed by projecting one end of each parallel conductor from one end of the heating element, and an insulating tube disposed around the heating element and having both ends projecting from both ends of the heating element and having a constant outer diameter. A self-temperature-controlled ribbon heater having a maximum outer diameter defined by the outer diameter of the insulating tube by filling the inside of the insulating tube at both ends of the heating element with an insulating resin in a state where the outer lead is inserted. . 2. A heater for heating a fluorescent discharge tube, comprising: a flat heating element having self-temperature controllability; a plurality of parallel conductive wires arranged in the heating element in a longitudinal direction thereof; The external lead includes an outer lead formed by projecting one end of each parallel conductor from one end of the heating element, and an insulating coating disposed around the heating element and having both ends projecting from both ends of the heating element. With the insert inserted, both ends of the insulating coating of the portion protruding from the heating element are fused and sealed in the thickness direction of the flat heating element, and the entire flat heating element is covered with the insulating coating. A self-controlled temperature controlled ribbon heater.