JPH1064685A - Cold cathode fluorescent lamp with heater - Google Patents

Abstract

(57) [Problem] In a conventional cold-cathode fluorescent lamp with a heater, the mercury vapor is generated by the temperature distribution in the bulb because the temperature is only kept by the heater so that the mercury is not excessively liquefied at a low temperature. This causes problems such as insufficient brightness at startup. According to the present invention, a heater (4) is provided over the entire length (L) of a bulb (3) of a cold cathode fluorescent lamp (2), and a central portion (3b) of the cold cathode fluorescent lamp (2) when the cold cathode fluorescent lamp (2) is not lit. Is a cold cathode fluorescent lamp 1 with a heater whose heating value is adjusted so as to have a substantially uniform temperature distribution so as not to make the temperature higher than both end portions 3c. The problem is solved assuming that mercury vapor is present in the vicinity of the central portion 3b of the bulb having a suitably low temperature at the time of preheating, and that a lighting luminance which does not hinder practical use can be obtained immediately after the start of discharge by applying a lighting voltage. Things.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold-cathode fluorescent lamp used as, for example, illumination of an automobile instrument, a backlight light source of a liquid crystal display, a light source for reading a facsimile, and the like. The present invention relates to a cold cathode fluorescent lamp with a heater having a configuration in which a heater is provided on the outer diameter of a bulb for the purpose of improving the starting characteristics.

[0002]

2. Description of the Related Art An example of a conventional fluorescent lamp equipped with a heater of this type is disclosed, for example, in Japanese Patent Application Laid-Open No. 4-172221. A fluorescent lamp in which a heating wire is spirally wound with a pitch smaller than the diameter is disclosed. FIG. 1 (C) shows a fluorescent lamp in which the heating wire is spirally wound with a dense pitch at the center of the bulb. It is shown.

[0003]

However, in the above-described conventional fluorescent lamp equipped with a heater, the start-up time can be improved without excessive liquefaction of mercury vapor in cold weather. , On the other hand,
It has been found that the provision of the heater causes the following problems.

That is, when the pitch is made dense at the center of the bulb as shown in FIG. 1 (C), the temperature distribution along the length L direction of the bulb at the time of preheating before lighting is shown in FIG. P
The temperature at the center is higher than at both ends as shown by. At this time, since the mercury vapor in the bulb has a characteristic of moving to a low temperature part, the mercury vapor is insufficient at the center immediately after the lighting voltage is applied, and the luminance is 5% at the time of normal lighting.
The problem is that only about 0% can be obtained, and sufficient brightness cannot be obtained at startup.

[0005] Further, when the lighting is performed in the above-described state, the discharge is performed in a state where the mercury vapor has moved to a low-temperature portion in the bulb, that is, both ends, whereby the discharge is performed.
Since the discharge is performed in a state where the mercury vapor is insufficient, there is a problem that the life of the fluorescent lamp is significantly shortened as compared with a normal lamp without a heater. The solution is to be an issue.

[0006]

According to the present invention, as a specific means for solving the above-mentioned conventional problems, a heater for improving a starting characteristic is provided at an outer diameter of a bulb of a cold cathode fluorescent lamp. In a cold cathode fluorescent lamp with a heater comprising
The heater is provided over the entire length of the bulb of the cold-cathode fluorescent lamp, and when the cold-cathode fluorescent lamp is not lit, the center of the cold-cathode fluorescent lamp does not have a higher temperature than both ends. By providing a cold-cathode fluorescent lamp with a heater, wherein the amount of generated heat is adjusted so as to have a substantially uniform temperature distribution, the brightness at the time of startup is improved and the life is shortened. The task is to be solved with a small number.

[0007]

Next, the present invention will be described in detail based on an embodiment shown in the drawings. 1 is a cold cathode fluorescent lamp with a heater according to the present invention. The cold cathode fluorescent lamp 1 with a heater has an outer diameter 3a of a bulb 3 of a cold cathode fluorescent lamp 2 and a cold start fluorescent lamp. The point that the heater 4 is provided for the purpose of shortening the time is similar to that of the conventional example.

Here, in the present invention, the heater 4 is provided over the entire length L of the bulb 3, and at this time, the heater 4 is turned off and the cold cathode fluorescent lamp is turned off. As shown by a heating temperature curve H in FIG. 2 showing the temperature distribution along the length L in the bulb 3 with respect to the lamp 2, the central portion 3b does not become hotter than both ends 3c, and 3b and both ends 3c are formed so as to be almost uniform without causing a temperature difference so much.

That is, in the bulb 3, both end portions 3c have a larger contact area with the outside air than the central portion 3b, and since the electrodes 5 and the lead wires 6 are provided, the heat radiation efficiency with respect to the outside air is high. Therefore, for example, when the heater 4 is formed by winding heating wires having a constant diameter at the same pitch, in other words, when the distribution of the heat generation amount along the length L direction of the bulb 3 is the same. Means that both ends 3c are lower in temperature than the center 3b.

Therefore, in the present invention, in the case of the heater 4 described above, the height of the heat radiating action of the both ends 3c is corrected by, for example, winding the heating wires with a fine pitch. The temperature distribution in the valve 3 is made substantially uniform in accordance with the above conditions.

In the present invention, the heater 4
It is not always necessary to use the above-mentioned heating wire winding. For example, a transparent electrode such as ITO is formed on the entire outer diameter 3a of the bulb 3, and then the bulb 3
It is also possible to adopt a configuration in which unnecessary portions are removed by etching or the like so that the inside becomes the condition of the temperature distribution described above.

Next, the operation and effect of the cold cathode fluorescent lamp 1 with a heater according to the present invention having the above-described configuration will be described.
First, in a cold state, when preheating is performed by the heater 4 prior to activation of the cold cathode fluorescent lamp 2, the temperature distribution in the bulb 3 is appropriately set in the central portion 3b with respect to the both end portions 3c by the configuration of the present invention. It is in a low state.

Accordingly, the mercury, which is kept in a vapor state by the heater 4, moves to the vicinity of the lower central portion 3b and becomes a state where it is present. If a lighting voltage is applied between the electrodes 5 in this state, There is no shortage of mercury vapor from the beginning of the discharge, and sufficient brightness can be obtained from the start of lighting.

Incidentally, the results of trial manufacture and examination by the inventor for realizing the present invention will be described. With the configuration of the present invention, the luminance immediately after lighting of the cold-cathode fluorescent lamp with heater 1 is 90% of the stable state. Therefore, it has been confirmed that practicality when used as, for example, illumination of automobile instruments, backlight of liquid crystal displays, and the like does not cause any problem.

Further, the fact that the discharge is started in a state where the mercury vapor is sufficiently present in the vicinity of the central portion 3b means that the discharge between the electrodes 5 in a state where the mercury vapor is insufficient is avoided. The shortage also prevents the life of the cold-cathode fluorescent lamp with heater 1, which has conventionally occurred, from being shortened, and the results of the above-mentioned trial manufacture and examination are about 3 to 5 times that of the conventional structure. It has been confirmed that life can be extended.

As described above, when the cold cathode fluorescent lamp 2 is used in a cold state, simply preventing the liquefaction of mercury by the heater 4 is completely insufficient. In addition, the distribution of mercury vapor in the valve 3 cannot achieve a sufficient effect unless control is performed by optimizing the temperature distribution.

FIG. 3 shows another embodiment of the present invention. In an actual use state of the cold cathode fluorescent lamp 2, the cold cathode fluorescent lamp 2 is mounted on a housing or the like.
In many cases, an external component 7 such as a socket is attached to both end portions 3c of the valve 3. In this case, the temperature distribution in the valve 3 described in the previous embodiment differs due to the attachment of the external component 7. there is a possibility.

In this embodiment, the above condition is dealt with, and the amount of heat generated by the heater 4 at the position corresponding to the change in the heat radiation efficiency at both ends 3c due to the attachment of the external component 7 is determined. By adjusting, the heating curve H in FIG.
This achieves the object of the present invention.

At this time, the adjustment of the amount of heat generated by the heater 4 is naturally performed in consideration of the thermal conductivity of the member on which the external component 7 is formed. In the case where the heat conductivity is excellent such as a metal, the amount of heat generated by the heater 4 in the portion is increased by, for example, increasing the winding pitch of the heating wire, and conversely, the external component 7 is insulated by a heat insulating material such as a resin. When the heating property is excellent, the amount of heat generated by the heater 4 in that portion can be reduced by, for example, increasing the winding pitch of the heating wire.

[0020]

As described above, according to the present invention, the heater is provided over the entire length of the bulb of the cold cathode fluorescent lamp, and when the cold cathode fluorescent lamp is not lit, the center of the cold cathode fluorescent lamp is turned off. Preheating by a heater prior to lighting by using a cold cathode fluorescent lamp with a heater whose heating value has been adjusted so that the temperature distribution is almost uniform so that the temperature is not higher than both ends. At this time, assuming that mercury vapor is present in the vicinity of the center of the bulb having a suitably low temperature and that a lighting luminance that does not hinder practical use can be obtained immediately after the start of discharge by applying a lighting voltage, this type of cooling with a heater is used. This is extremely effective in improving the performance of the cathode fluorescent lamp.

Further, since the discharge is performed in a state where the mercury vapor is sufficiently present as described above, it is possible to prevent the discharge from being performed in a state where the mercury vapor is insufficient as in the conventional example. Thus, an excellent effect of preventing the life of the cold cathode fluorescent lamp with a heater of this type from being shortened at the time of low-temperature lighting can also be achieved.

In addition, the heater is a cold-cathode fluorescent lamp with a heater in which the amount of generated heat is adjusted so as to correct the influence on the temperature distribution due to external components for holding the cold-cathode fluorescent lamp. Thus, the above-described effect can be more reliably corrected by correcting the deviation of the temperature distribution due to, for example, mounting of the socket.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of a cold cathode fluorescent lamp with a heater according to the present invention in a partially broken state.

FIG. 2 is a graph showing a state of a temperature distribution during heating by a heater;

FIG. 3 is an explanatory view showing another embodiment of a cold cathode fluorescent lamp with a heater according to the present invention in a main part.

FIG. 4 is a graph showing a state of a temperature distribution during heating by a conventional heater.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cold cathode fluorescent lamp with a heater 2 ... Cold cathode fluorescent lamp 3 ... Valve 3a ... Outside diameter 3b ... Central part 3c ... Both ends 4 ... Heater 5 ... Electrode 6 ... Lead wire 7 ... External parts L ... Valve length H ... Heating curve

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Haruho Kato 137-1 Morikaga, Hirai Akai, Iwaki-shi, Fukushima Prefecture (72) Inventor Yasuhide Yasuda 30-1 Uehira, Hirakita Shirato-ji, Iwaki-shi, Fukushima

Claims (2)

[Claims] 1. A cold-cathode fluorescent lamp with a heater comprising a heater for improving a starting characteristic at an outer diameter of a bulb of the cold-cathode fluorescent lamp, wherein the heater comprises the bulb of the cold-cathode fluorescent lamp. The cold cathode fluorescent lamp is positioned over the entire length of the cold cathode fluorescent lamp so that the central portion of the cold cathode fluorescent lamp has a substantially uniform temperature distribution that is not higher than both ends when the cold cathode fluorescent lamp is not lit. A cold-cathode fluorescent lamp with a heater, wherein the calorific value is adjusted. 2. The heater according to claim 1, wherein the heating value of the heater is adjusted so as to correct the influence on the temperature distribution by an external component for holding the cold cathode fluorescent lamp. Item 7. A cold cathode fluorescent lamp with a heater according to Item 1.