JPH0431734Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Purpose of the invention] (Field of industrial application) The invention provides a band-shaped external electrode along the axial direction on the outer surface of the bulb to promote discharge, and
This invention relates to a discharge lamp in which a heater is provided on the outer surface of the bulb to promote evaporation of mercury. (Prior Art) Cold cathode fluorescent lamps or hot cathode fluorescent lamps are used as backlights for liquid crystal televisions and liquid crystal display devices. The above-mentioned LCD televisions and liquid crystal display devices are sometimes used in environments with severe temperature conditions. For example, fluorescent lamps for backlights used in vehicle meters are used at temperatures ranging from about +40°C to -30°C. Used in a wide temperature range.

Even under such harsh temperature environments, lamps are required to have good start-up performance and start-up characteristics at the beginning of use.

In order to improve the starting performance, that is, the discharge initiation characteristics, in addition to the internal electrodes provided inside both ends of the fluorescent lamp, an external electrode is formed in close contact with the outer surface of the bulb in the form of a band, and this external electrode is connected to a nearby conductor, i.e. Lamps have been proposed for use with starting auxiliary electrodes.

According to this, since the external electrode serves as a starting auxiliary electrode, starting performance is improved and the starting voltage can be lowered.

On the other hand, it is known that a heater is attached to the bulb in order to improve the start-up characteristics.According to this, the heater heats the bulb to evaporate the mercury sealed inside, and the time it takes to reach stable lighting. This aims to shorten the so-called rise time.

(Problem to be solved by the invention) By the way, when a band-shaped external electrode and a heater are both provided on the outer surface of the bulb as described above, there is a concern that these external electrodes and the heater may block the light emitted from the bulb. .

Therefore, in order to minimize light shielding by these external electrodes and heaters, it is desirable to form these external electrodes and heaters in a superimposed manner.

In this case, if an external electrode is provided in close contact with the outer surface of the bulb, and a heater is provided on the outer surface of the external electrode with an insulating coating interposed therebetween, the starting performance is good, but the temperature rise of the bulb is poor.

On the other hand, if the heater is placed in close contact with the outer surface of the valve,
If an external electrode is provided on the outer surface of the heater via an insulating film, the temperature rise of the bulb will be improved, but there will be a problem that the startability will be poor.

The present invention aims to provide a discharge lamp which has good starting performance and bulb temperature rising performance by reducing the degree of light shielding.

[Structure of the invention] (Means for solving the problems) In the invention, the heater is polymerized and formed on the outer surface of the external electrode via an insulating film, and a part of the heater is made to protrude from the external electrode, and this protruding part is It is characterized by being in close contact with the outer surface of the valve.

(Function) According to the present invention, the heater, which is formed by polymerization on the outer surface of the external electrode via an insulating film, partially protrudes from the external electrode and contacts the outer surface of the bulb, so that the heater is in direct contact with the bulb. portion heats the valve, increasing temperature raising performance and heat retention performance. Moreover, since the external electrode is in contact with the outer surface of the bulb, good starting performance is maintained. Further, the light is blocked by the amount of light that protrudes from the external electrode of the heater, but since this amount of protrusion may be small, the light blocking ratio can be reduced.

(Example) The present invention will be described below based on an example shown in FIGS. 1 and 2.

The drawing shows a cold cathode fluorescent lamp as a backlight light source used in a vehicle meter. In the drawing, 1 is a bulb bent into an annular shape and made of quartz, hard or soft glass. The inner surface of this bulb 1 is coated with a phosphor coating 2.
The bulb 1 is filled with a predetermined amount of mercury and a rare gas consisting of at least one of xenon, krypton, argon, neon, helium, and the like.

Inside the bulb 1 are internal electrodes 3, 3 located at both ends.
is provided. These internal electrodes 3, 3 are cold cathodes made of nickel, for example, and these cold cathode type internal electrodes 3, 3 are connected to lead wires 4, 4, respectively. These lead wires 4, 4 pass through the end wall of the bulb 1 in an airtight manner and are led out.

An external electrode 5 is provided in close contact with the outer surface of the bulb 1. The external electrode 5 is formed substantially over the entire length between both ends of the bulb 1, and has a band shape having a substantially uniform width w1 along the axial direction. Note that the external electrode 5 is made of a conductive coating film, and is formed by applying, for example, silver paste, and a power supply connection cord 6 is connected to the end of the external electrode 5.

An insulating coating 7 is formed on the outer surface of the external electrode 5, and this insulating coating 7 covers substantially the entirety of the external electrode 5.

A heater 8 is superimposed on the outer surface of the insulating film 7. The heater 8 is, for example, a mesh heater, and is formed into a porous thin net shape by chemically etching a thin stainless steel plate. The heater 8 has a width w2 larger than the width w1 of the external electrode 5, and is shaped like a band having a substantially uniform width along the axial direction. It protrudes beyond both edges in the width direction, and these protruding portions 8a, 8a are in direct contact with the outer surface of the bulb 1. Note that power connection cords 9, 9 are connected to the ends of the heater 8 by means such as soldering.

Further, an insulating coating 10 is provided on the outer surface of the heater 8.
is formed. This insulating coating 10 covers substantially the entire heater 8 .

In a cold cathode fluorescent lamp having such a configuration, when the internal electrodes 3, 3 are connected to a power source and a voltage is applied to the external electrode 5, the external electrode 5 becomes a proximal conductor and functions as an auxiliary electrode. , thus promoting discharge, thereby generating glow discharge inside the bulb 1. As a result, starting performance is improved and starting voltage can be lowered.

This glow discharge causes the mercury vapor within the bulb 1 to emit ultraviolet light, which excites the phosphor coating 2 formed on the inner surface of the bulb 1 to emit visible light. This visible light is emitted to the outside of the bulb 1.

Furthermore, when the heater 8 provided on the outer surface of the external electrode 5 is energized, the heater 8 generates heat and heats the bulb 1 . Therefore, the mercury sealed inside is actively evaporated and the time required to reach stable lighting is shortened, making it possible to shorten the so-called start-up time.

In the case of this embodiment, since the heater 8 is provided outside the external electrode 5, the heater 8 is connected to the valve 1.
Although there is a concern that the heating performance of the bulb 1 will deteriorate due to the fact that the heater 8 is not in close contact with the outer electrode 5, the width w2 of the heater 8 may be
The outer electrode 5 of the heater 8 is made larger than the width w1, so that both sides of the heater 8 protrude from both widthwise edges of the external electrode 5, and these protruding portions 8a, 8a are brought into direct contact with the outer surface of the bulb 1. Even if the heating capacity is insufficient only in the overlapping portion, the protruding portions 8a, 8a directly heat the outer surface of the bulb 1, thereby making up for the shortage.

Therefore, the heating capacity of the bulb 1 is not insufficient, so that the temperature increase and the heat retention effect can be performed satisfactorily.

Moreover, since the external electrode 5 is in direct contact with the outer surface of the bulb 1, the starting performance as a proximal conductor can be greatly maintained.

In addition, in the heater 8, heat is generated also in the portion overlapping with the external electrode 5, and the bulb is heated also in this overlapping portion, so the external electrodes on both sides of the heater 8
The protruding amount of the protruding portions 8a, 8a may be small, so that the protruding portions 8a, 8a protrude from the heater 8.
Even if the bulbs a and 8a are provided, there is no fear that the rate of blocking the light emitted from the bulb 1 will become extremely large.

In particular, a mesh heater is used as the heater 8,
When a translucent coating is used as the insulating coating 10, the amount of light shielded by providing the protruding portions 8a, 8a is extremely small, and can be made to the extent that it has almost no effect.

Note that the present invention is not limited to the above embodiments.

That is, although the above embodiment describes a cold cathode fluorescent lamp bent into an annular shape, the shape of the bulb is not limited to an annular shape, but a linear bulb 1 as shown in another embodiment in FIG. You can.

Further, in the above embodiment, the internal electrodes 3, 3 were sealed at both ends of the bulb 1, and the external electrode 5 was provided as a proximal conductor on the outer surface, but as shown in FIG. Internal electrodes 3 on both ends,
3 may be sealed, and an external electrode 5 serving as the other discharge electrode may be provided on the outer surface.

Furthermore, in the above embodiment, the width of the heater 8 is
The width of the heater 8 is made larger than the width of the external electrode 5, and both sides of the heater 8 protrude from both widthwise edges of the external electrode 5.
These protruding portions 8a, 8a are brought into direct contact with the outer surface of the bulb 1, but in the present invention, as in another embodiment shown in FIG. 4, one side of the heater 8 overlaps the external electrode 5, and the other side The structure may be such that the valve contacts the outer surface of the valve 1.

Instead of the outermost insulating coating 10, a light-transmitting heat-shrinkable tube may be placed over the entire outer surface of the bulb to provide insulation protection for the heater 8.

Furthermore, the internal electrode 3 is not limited to a cold cathode, but may be a hot and cold cathode using a filament.

[Effects of the invention] As explained above, according to the invention, the heater, which is polymerized and formed on the outer surface of the external electrode via an insulating film, has a part protruding from the side edge of the external electrode, and this protruding part is connected to the outside of the bulb. Because it came into contact with the surface,
The portion of the heater that is in direct contact with the bulb heats the bulb, increasing the temperature raising performance and heat retention performance of the bulb. Moreover, since the external electrode is in contact with the outer surface of the bulb, good starting performance is maintained. Further, the light is blocked by the amount of light that protrudes from the external electrode of the heater, but since this amount of protrusion may be small, the light blocking ratio can be reduced.

[Brief explanation of the drawing]

1 and 2 show one embodiment of the present invention, FIG. 1 is a perspective view showing the overall structure of the lamp, FIG. 2 is a sectional view taken along the line - - in FIG. FIG. 4 is a perspective view showing the overall structure of a lamp showing another embodiment of the present invention, and FIG. 4 is a sectional view showing still another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Bulb, 2... Phosphor coating, 3... Internal electrode, 5... External electrode, 7... Insulating coating, 8...
... Heater, 8a, 8b ... Protruding part of heater,
10...Insulating coating.

Claims (1)

[Scope of Claim for Utility Model Registration] An internal electrode is provided inside a bulb having a phosphor coating formed on its inner surface, and an external electrode in the form of a band is provided in close contact with the outer surface of the bulb along the tube axis direction, and A heater is attached to the outer surface of the above valve,
In a discharge lamp in which mercury and a rare gas are sealed in the bulb and the heater is used to promote the evaporation of mercury, the heater is formed by polymerizing the outer surface of the outer electrode via an insulating film, and partially attaching the outer electrode to the outer electrode. A discharge lamp characterized by an electrode that protrudes from the bulb, and this protruding portion that is in close contact with the outer surface of the bulb.