JP2534054B2 - Self-temperature control type flat 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 element is heated at a low temperature and the like. The present invention relates to a self-temperature control type flat heater having a heating element obtained by mixing

[Conventional technology]

3 (a) and 3 (b) are a plan view and a side view showing a conventional self-temperature control type flat heater (hereinafter, abbreviated as a heater as appropriate) 1, in which 2 indicates a decrease in ambient temperature. The resistance value decreases in accordance with the so-called self-temperature controllable flat heating element, 3 and 4 are parallel conductors for energizing the heating element 2, 5 is a coating for the heating element 2 and the parallel conductors 3 and 4. Is an insulator, d is the diameter of the parallel conductors 3 and 4, t is the thickness of the insulator 5, T is the thickness of the heating element 2, and W is the width of the heating element 2.

Next, the operation will be described. In general, a liquid crystal display (hereinafter abbreviated as LCD) device does not emit light, and therefore, illumination from behind the device is required depending on external light conditions. Therefore, the development of a high-efficiency and high-brightness thin back lighting (hereinafter abbreviated as a backlight) that does not impair the energy saving and thinness of the LCD has been awaited. As an example of this kind of backlight, "Technical Report of the Television Society of Japan" IPD105-2
(Published February 25, 1986), 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 of the enclosed mercury. For example,
If the ambient temperature drops below -10 ° C, the discharge tube will not operate normally.

Therefore, in order to ensure the normal operation of the discharge tube,
The first conceivable way is to heat the discharge tube at a low temperature, and the heater 1 shown in FIGS. 3 (a) and 3 (b) is used in such a case.

FIG. 4 is a perspective view showing a usage example thereof, in which the above-mentioned heater 1 is used for the fluorescent discharge tube 6. If a predetermined voltage is applied between the parallel conductors 3 and 4, heating by the heating element 2 is performed when the ambient temperature drops by a certain amount or more,
The normal lighting operation of the fluorescent discharge tube 6 can be ensured.

[Problems to be solved by the invention]

Since the conventional self-temperature control type flat heater is configured as described above, it has the following problems.

That is, in order to perform sufficient heating in a short time at low temperature, it is necessary to enhance the heating ability of the heating element 2. As this means, a means for decreasing the width W of the heating element 2 to raise the surface temperature, a means for increasing the wall thickness T of the heating element 2 to increase the heating capacity, or the like can be considered.

However, the former cannot keep the width W below a certain value due to the manufacturing reason that the yield of the heating element 2 is lowered, and the latter also increases the thickness T of the heating element 2 to increase the backlight. Is not valid for space reasons as the overall thickness increases. Further, when the space between the parallel conductors 3 and 4 is increased to widen the width of the heating element 2 and a high voltage is applied to increase the heating capacity, the heating capacity per unit area of the heating element 2 is uneven. Therefore, there is a possibility that the heat generation efficiency may be reduced or that local heating may occur.

Therefore, as shown in FIG. 5, a means for using two heaters 1 described above and doubling the heating capacity has been adopted, but the angle θ ₁ for shielding the light from the fluorescent discharge tube 6 is also correspondingly. However, there is a problem in that the efficiency and brightness of the backlight significantly deteriorate.

The present invention has been made to solve the above problems, and it is possible to suppress deterioration of utilization efficiency of objects to be heated during heating as much as possible without causing problems in manufacturing or space as described above. The purpose is to obtain a self-temperature control type flat heater.

[Means for solving problems]

The self-temperature control type flat heater according to the present invention forms a self-temperature controllable flat heating element between two parallel conductors facing each other, and the two parallel conducting wires and the flat heating element are made of an insulator. A common conductor made of one conductor is provided between the two parallel conductors so as to be in contact with the flat heating element.
A voltage can be applied between the parallel conductors and the common conductor of the book.

[Work]

The heating element according to the present invention has a heating capacity that is twice as large as that of the conventional heating element, but it is possible to divide the voltage application by sharing the common conductor, and to suppress the increase in width dimension as much as possible. it can.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In FIGS. 1 (a) and 1 (b), 7 is a self-temperature control type flat heater, 8 is a self-temperature control type flat heating element, 9 and 10
Is a parallel conductor wire, 11 is a middle conductor wire between the parallel conductor wires 9 and 10, and is a common conductor wire having the same material, the same length, and the same diameter, and 12 is an insulator. As is clear from the figure, the heater 7 has a heating capacity equivalent to that of the two heaters 1 shown in FIG.

Next, the operation will be described. As in the conventional case, as shown in FIG. 2, the heater 7 is attached to the fluorescent discharge tube 6 to heat it. By applying the common conducting wire 11 in common, the voltage application to the heating element 8 can be divided into two between the parallel conducting wire 9 and the common conducting wire 11 and between the common conducting wire 11 and the parallel conducting wire 10.

By the way, as described above, the heater 7 is the heater 1 shown in FIG.
Although the heater 1 has a heating capacity of two, the width dimension Z ₁ of the two heaters 1 in FIG. 5 is (2W + 4d + 4t), while the width dimension Z ₂ of the heater 7 is (2W + 3d + 2t). Becomes In other words, Z ₂ is smaller than Z ₁ by (d + 2t). Therefore, corresponding to this value, the angle θ ₂ for blocking the light from the fluorescent discharge tube 6 is also the angle θ _{1 in} the case of FIG.
It will be smaller than The difference between θ ₂ and θ ₁ is
At first glance, it doesn't seem so big, but in order to improve the efficiency of the backlight, it cannot be ignored.

Further, in FIG. 5, the means for fixing the two heaters 1 at the same time must be devised, whereas in the case of FIG. 2, the heater 7 can be fixed as it is, and the assembling becomes easier.

From the viewpoint of manufacturing, the heating element 8 of the heater 7 in FIG. 1 is twice as large as the heating element 2 of the heater 1 in FIG. 3, so that the material yield is improved. Has become. Further, the heater 7 connects the common conductor 11 to the parallel conductors 9 and 10.
Since it is configured to be shared with both of the above, it is possible to save the material for one parallel conductor wire as compared with the case of using two heaters 1. The same applies to the material of the insulator 12.

In addition, in the present embodiment, the case where it is used for the backlight of the LCD has been described as an example, but it goes without saying that the self-temperature control type flat heater of the present invention can be applied to various other uses. .

〔The invention's effect〕

As described above, according to the present invention, the two facing each other
A flat-shaped heating element with self-temperature controllability is formed between two parallel conducting wires, and the two parallel conducting wires and the flat-shaped heating element are covered with an insulator, and one parallel conductor is formed between the two parallel conducting wires. Since a common conductor is formed in contact with the flat heating element so that a voltage can be applied between each of the two parallel conductors and the common conductor, the heater width is reduced and the amount of heat generated per unit area is reduced. There is an effect that can be increased.

Further, when the object to be heated is a light source such as a fluorescent discharge tube, the area and angle for shielding the light can be reduced, so that there is an effect that the lighting effect can be made highly efficient.

[Brief description of drawings]

1 (a) and 1 (b) are a plan view and a side view showing a self-temperature control type flat heater according to an embodiment of the present invention, and FIG. 2 is a sectional view showing a mounting state of the one shown in FIG. 1, and FIG. FIGS. (A) and (b) are a plan view and a side view showing a conventional self-temperature control type flat heater, and FIG. 4 and FIG.
It is a perspective view and a sectional view showing the attachment state of the thing of a figure. Reference numeral 7 is a self-temperature control type flat heater, 8 is a heating element, 9 and 10 are parallel conductors, 11 is a common conductor, and 12 is an insulator. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

(57) [Claims] 1. A self-temperature control device comprising a flat heating element having self-temperature controllability formed between two parallel conductors facing each other, and the two parallel conducting wires and the flat heating element being covered with an insulator. In the control type flat heater, a common conductor made of one conductor is provided between the two parallel conductors in contact with the flat heating element, and a voltage is applied between the two parallel conductors and the common conductor. A self-temperature control type flat heater characterized by being capable of applying a voltage.