JPS59186246A - Discharge lamp - Google Patents

Abstract

PURPOSE:To protect the border section between a mesh portion and power supply terminal portion from breaking by making a heat production resistor at the power supply terminal narrower in circumferential direction of bulb than the mesh section thereby easily contacting it tightly along the outercircumferential face of bulb. CONSTITUTION:A heat production resistor 7 for heating a bulb 1 and improving the starting performance is provided on the outercircumferential face of bulb 1. Said resistor 7 is constructed as a mesh by applying photo-etching onto a thin stainless steel and coated semi-circumferentially over the outercircumference of bulb 1 in axial direction. Then power supply terminal sections 10, 10 are provided integrally at both ends at the electrode 2, 2 side of meshed section 9 to form such that the width T1 in circumferential direction of bulb 1 at said sections 10, 10 will be shorter than T2 at the meshed section 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a discharge lamp used as a light source for illuminating an instrument display panel of an automobile or the like.

[Technical background of the invention and its problems]

Recently, the instrument display panels of automobiles and the like are changing to digital displays, and these digital display panels use cold cathode/discharge lamps as the light source for the liquid crystal panel. Since this cold cathode discharge lamp does not require power for heating the cathode, it immediately starts discharging and emits light, and is highly suitable as a light source for the above-mentioned instrument display panels and the like.

However, when cars are used in cold regions or in winter, the temperature of the discharge lamp itself is low, so the mercury vapor pressure in the pulp at startup is low.
As a result, the starting performance, which is the original characteristic, is impaired, and
In the worst case, there was a problem in which the engine could not be started.

For this reason, recently a resistance heating element made of a thin metal material formed in a mesh shape was attached to the outer peripheral surface of the pulp.
A discharge lamp has been developed in which starting performance is improved by heating the pulp using this resistance heating element. This resistance heating element is composed of a mesh section in which many holes are arranged in parallel, and a power supply terminal section in the form of a strip with no mesh, which is integrally provided at the end of this mesh section. are located at both ends of the valve and are in close contact with the outer peripheral surface of the valve.

However, according to this resistance heating element, the power supply terminal part has no mesh or holes, so it is less flexible than the mesh part, and therefore has high rigidity and strong springback, so it adheres closely to the outer circumferential surface of the cylindrical bulb. It becomes extremely difficult to do so. As a result, both ends of the power supply terminal part tend to lift up, which is not only unsightly in appearance, but also causes problems in that excessive force is applied to the boundary between the mesh part and the power supply terminal, causing damage to this boundary part.

[Purpose of the invention]

The present invention was made based on these circumstances, and
The fourth objective is to provide a highly reliable discharge lamp in which the resistance heating element can be easily attached closely along the outer circumferential surface of the bulb, and damage to the boundary between the mesh part and the power supply terminal part can be prevented. do.

[Summary of the invention]

That is, in order to achieve the above-mentioned object, the present invention is characterized in that the width along the circumferential direction of the bulb at the power supply terminal section is also narrower than the width of the mesh section.

[Embodiments of the invention]

The present invention will be explained below based on an embodiment shown in the drawings.

FIG. 1 shows a cold cathode discharge lamp for illuminating, for example, an automobile's instrument display panel from the back, and numeral 1 denotes a cylindrical straight pulp. Both ends of the bulb 1 have a stem 3 with electrodes 2, 2.
, 3, and lead wires 4, 4 connected to the electrodes 2.2 are led out from the stems 3, 3.

Further, an inert gas mainly composed of argon or the like and mercury are sealed in the pulp 1 through an exhaust pipe 5, and a phosphor coating 6 is coated on the inner surface of the bulb 1.

A resistance heating element 7 is provided on the outer peripheral surface of such a valve 1 to heat the valve 1 and improve startability. This resistance heating element 7 is made of, for example, a thin film of stainless steel (photo-etched or etched) to form a net shape as a whole, and is attached to the outer peripheral surface of the valve 1 along the entire length along the tube axis direction. The resistance heating element 7 has a mesh portion 9 in which a large number of square-shaped through holes 8 are arranged in parallel.

Power supply terminal portions 10 and 10 are integrally provided at both ends of the mesh portion 9 located on the electrodes 2, 2 side. The power supply terminal portion 10.10 has a block-like shape without a mesh, and is integrally connected to the mesh frame 9a . . . forming the through hole 8 of the mesh portion 9. The width T of the power supply terminal portion 10.10 along the circumferential direction of the bulb 1 is also formed to be much smaller than the width T2 of the mesh portion 9 along the circumferential direction of the bulb 1, and the width T2 of the power supply terminal portion 10. It forms a band along the Moreover, in this embodiment, as a preferable example, one end of the power supply terminal section 10.10 is inserted into the mesh section 9 by a predetermined length, so that the range of connection with the mesh section 9 is increased.

The lead wire 1 is connected to such a power supply terminal portion 10.10.
1.11 are electrically connected, and these lead wires 1
1.11, the resistance heating element 7 is energized.

The entire outer peripheral surface of the bulb 1 is covered with a transparent heat-shrinkable tube 12, and the resistance heating element 7 is held in close contact with the outer peripheral surface of the bulb 1 by this tube 12.

According to this configuration, the width T along the circumferential direction of the bulb 1 at the power supply terminal portion 10° 10 is formed to be much narrower than the width T2 along the circumferential direction of the mesh portion 9, so that the resistance heating element 7 When bringing the power supply terminal portion 10.10 into close contact with the outer peripheral surface of the bulb 1, it is not necessary to curve the power supply terminal portion 10.10 greatly along the curvature of the outer peripheral surface of the bulb 1. Therefore, as the power supply terminal portion 10.10 rises, Therefore, they can be easily brought into close contact along the outer circumferential surface of the valve 1. As a result, no excessive force is applied to the boundary between the mesh portion 9 and the power supply terminal portion 10.10, and damage to this portion can be prevented. Moreover, since one end of this power supply terminal portion 10°10 is inserted into the mesh portion 9, the power supply terminal portion 10
．． 10 and the mesh part 9 can be made sufficiently long, the mechanical strength of this connection part is improved and it effectively contributes to preventing damage, and the electrical resistance is also reduced, so a stable electrical connection can be achieved. characteristics are obtained.

In the above-described embodiment, the resistance heating element is applied over half the circumference of the bulb, but it may be applied over the entire circumference, and the means for maintaining close contact with the bulb is not limited to the above-mentioned embodiment.

Furthermore, the discharge lamp according to the present invention is not limited to the cold cathode type.
It is also applicable to hot cathode type discharge lamps.

〔Effect of the invention〕

According to the present invention described in detail above, since the width of the power supply terminal portion along the circumferential direction of the bulb is also formed to be narrower than the width of the mesh portion, the power supply terminal portion does not lift up from the bulb.
The resistance heating element can be easily brought into close contact with the outer peripheral surface of the bulb.

Therefore, there are advantages in that the appearance is improved, and the connecting portion between the power supply terminal portion and the mesh portion can be prevented from being damaged, and reliability is improved.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, with the first figure being a perspective view and the second figure being a perspective view.
The figure is a sectional view, FIG. 3 is a plan view of the resistance heating element, and FIG. 4 is an enlarged view of the part 2 in FIG. 3. 1... Bulb, 2... Electrode, 7... Resistance heating element, 8
... Hole (through hole) 1.9... Mesh part, 10... Power supply terminal part.

Claims (1)

[Scope of Claims] (1) Comprising a pulp with electrodes sealed at both ends and a mesh-like resistance heating element made of a thin metal material adhered to the outer peripheral surface of the pulp, the resistance heating element The body consists of a mesh section in which a large number of holes are arranged in parallel, and a power supply terminal section without a mesh provided integrally and continuously at the end of this mesh section, and the power supply terminal section extends in the circumferential direction of the pulp. Discharge lamp 0 characterized in that the width along the circumferential direction of the pulp in the mesh portion is also narrow. A discharge lamp according to claim 13.