JP2730790B2 - Low pressure discharge lamp and display device using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a low-pressure discharge lamp in which an external lead wire connected to an electrode is led out of a crushable sealing portion formed at an end of a bulb. The present invention relates to a display device using the same.

(Prior Art) Recently, attempts have been made to use a low-pressure discharge lamp as a display indicator on a display panel of an acoustic device, a measuring device, or the like.

For example, a low-pressure discharge lamp such as a xenon glow discharge tube,
The inner diameter of the bulb is made into a very thin hollow needle of 2 mm to 3 mm or less, and one end of this discharge lamp is attached to the rotation pointer shaft of the meter.
A device has been developed in which the rotation of the rotation pointer shaft causes the discharge lamp to rotate integrally, and this discharge lamp performs the function of a pointer, and furthermore, by turning on the discharge lamp. Since this emits light by itself and illuminates the display scale portion, there is an advantage that another special illumination is not required.

Discharge lamps used as pointers for such meters are:
An internal electrode is provided inside the elongated hollow rod-shaped valve, and a band-shaped external electrode is provided on the outer surface of the valve along the axial direction. To generate a glow discharge.

A light-shielding coating made of a synthetic resin is formed on the outer surface of the bulb, and the light-shielding coating is formed except for a thin strip-shaped light transmission slit extending in the axial direction of the bulb. Emits light. Accordingly, this type of discharge lamp is an aperture-type lamp, and the light-emitting portion of the pointer has a very thin needle shape.

In such a low-pressure discharge lamp, a crush sealing portion is formed at one end of a bulb, an internal electrode is sealed in the sealing portion, and an external lead connected from the end of the sealing portion to the internal electrode. The line has been derived. A first power receiving terminal made of a film obtained by firing a conductive paste to which the external lead wire is connected is provided on the outer surface of the crushed sealing portion.

The external electrode is also formed of a film obtained by firing a conductive paste, and a second power receiving terminal formed of a film obtained by firing the conductive paste to be connected to the external electrode is axially moved from the first power receiving terminal. It is formed separately.

Then, there has been proposed a structure in which the first and second power receiving terminals are brought into contact with the first and second power supply terminals provided on the valve holder, and are connected to a power supply through the first and second power supply terminals.

(Problems to be Solved by the Invention) However, when a conductive film formed on the outer surface of the crushable sealing portion is connected to an external lead wire led out to the crushing sealing portion, conventionally, the crushing sealing is simply performed. Since only the conductive paste is applied to the portion and the two are brought into contact with each other, the contact area between the conductive film and the external lead wire is small, and there is a problem that poor contact easily occurs.

The present invention has been made based on such circumstances,
It is an object of the present invention to provide a low-pressure discharge lamp in which a contact area between a conductive film and an external lead wire is increased and a poor contact can be prevented, and a display device using the same.

[Structure of the Invention] (Means for Solving the Problems) The invention described in the first aspect is a valve in which an electrode is provided inside and a sealing portion is formed at an end; An external lead wire, the other end of which is led out through the sealing portion; a concave portion formed in the sealing portion where the external lead wire is led; And a conductive film formed so as to be connected to the external lead wire by filling the material and applying the conductive material so as to be continuous with the outer surface of the sealing portion. .

The invention according to a second aspect is a display device using the low-pressure discharge lamp according to the first aspect as a light source.

According to the first aspect of the present invention, since the recess is filled with a conductive material and a conductive film is formed on the outer surface of the sealing portion with the conductive material, the conductive film is formed of an external lead. A large contact is made with the wire, thus increasing the contact area between the two, thereby eliminating poor contact. In addition, the material used to fill the recess and the material applied to the outer surface of the sealing portion are the same conductive material, making it extremely easy It is possible to manufacture.

According to the second aspect of the invention, it is possible to provide a display device with high electrical connection reliability.

(Example) Hereinafter, the present invention will be described based on an example shown in the drawings.

In the figure, reference numeral 1 denotes a cold cathode xenon glow discharge lamp used for a display needle of an instrument, and the discharge lamp 1 includes a bulb 2 having an elongated discharge space 3 formed therein. The bulb 2 is made of a glass tube, for example, having an outer diameter of 2.5 mm,
It has an inner diameter of 1.5 mm and a total length of about 60 mm, forming needles.

One end of the valve 2 has a pinch seal structure 210 as shown in FIG. 3, and the other end has a tip-off structure 250.

The internal electrode 4 is sealed in a pinch seal portion 210 formed at one end of the bulb 2. The internal electrode 4 is formed of a cold cathode, and includes an electrode head 41, a lead wire 42 also serving as an electrode axis, and an electron emitting material (emitter) 43 filled in the electrode head 41.

The lead wire 42 passes through the crush sealing portion 210 in an airtight manner. The electrode shaft lead wire 42 is formed of a dumet wire having a wire diameter d of about 0.5 mm, and the electrode head 41 is fixed to an end extending into the discharge space 3.

The electrode head 41 is formed of a low melting point metal tube such as nickel (Ni) or zirconium (Zr) -aluminum (Al) alloy having both ends opened.

The electrode head 41 has, for example, lanthanum boride (LaB ₆ )
Lanthanide-based rare-earth electron emitters such as
43 powders are filled.

A fluorescent film 6 is formed on the inner surface of the bulb 2 facing the discharge space 3, and xenon gas is provided in the bulb 2 at 5 to 40 Torr, preferably in a range of 20 to 40 Torr.
r, specifically, about 30 Torr.

On the outer surface of the bulb 2, there is provided an external electrode 7 having a band shape along the axial direction. This external electrode 7 is made of a paste such as carbon phenol or silver epoxy.
In the form of a strip along the axial direction of, and firing.

One end of the external electrode 7 is located at a portion facing the internal electrode 4, and the other end extends to the tip end surface of the tip-off portion 250 of the bulb 2.

The width of the external electrode 7 is formed in a range of not less than 1/3 of the circumferential length of the bulb 2, that is, in a region forming an angle of not less than 120 °.

The bulb 2 has a first power receiving terminal 10 formed on an outer surface of an end portion sealing the cold cathode 4 therein. This first
The power receiving terminal 10 is formed in a film shape obtained by applying a conductive paste such as silver epoxy and baking the same, and is connected to the lead wire 42.

In this case, as shown in detail in FIG.
For example, a conical concave portion 5 is formed around 42, and the conductive paste applied to the crush sealing portion 210 is also filled in the concave portion 5, so that the lead wire 42 and the conductive coating,
That is, a large contact area with the first power receiving terminal 10 is ensured.

Therefore, the first power receiving terminal 10 is connected to the cold cathode 4.

The first power receiving terminal 10 is provided on the outer surface of the bulb 2.
A second power receiving terminal 11 is formed at a position spaced apart in the axial direction with respect to. The second power receiving terminal 11 is also formed by applying a conductive paste such as silver epoxy and baking it.
It has a predetermined width and extends in the circumferential direction. The second power receiving terminal 11 is connected to the external electrode 7. The second
The power receiving terminal 11 is formed so as to avoid a slit portion 9 of the light shielding film 8 described later.

Further, a light-shielding coating 8 is formed on the outer surface of the bulb 2.

The light-shielding film 8 has components of carbon, epoxy resin, and an adhesive, and is applied to the surface of the bulb 2 on which the external electrodes 7 are provided so as to cover the external electrodes 7 and formed by firing the applied film. Have been.

The light-shielding film 8 is provided with a light-transmitting slit portion 9 which is located on the surface opposite to the surface on which the external electrodes 7 are provided and extends in the axial direction. That is, the light transmission slit portion 9 is formed as a transparent portion where the light shielding film 8 is not formed.

More specifically, as shown in a sectional view in FIG. 4, an external electrode 7 is provided on one surface of the bulb 2, and the external electrode 7 is covered with a light-shielding film 8. A light-shielding film 8 is formed on the other surface 180 degrees opposite to the electrode 7.
Are formed in the light transmission slit portion 9 which is not formed.

The width of the light transmission slit 9 is smaller than the width of the external electrode 7.

The light in the bulb 2 is emitted to the outside only through the light transmitting slit 9, so that the discharge lamp 1 has an aperture shape.

The second power receiving terminal 11 is not covered with the light shielding film 8 as shown in FIG. 5, but is exposed on the outer surface of the lamp 1.

The thus configured xenon discharge lamp 1 is mounted on a lamp holder 20.

The lamp holder 20 is formed of an electrically insulating material such as a synthetic resin and has a U-shaped cross section, and holds the first and second power supply terminal tongue pieces 21 and 22 spaced apart in the longitudinal direction.

The power supply terminal tongues 21 and 22 are formed by bending a conductive leaf spring such as phosphor bronze into a substantially U-shape, and as shown in FIG. It is something to pinch.

The lamp holder 20 is fixed to a display rotation shaft 25 of the instrument, and is turned integrally when the rotation shaft 25 rotates.

The rotating shaft 25 of this embodiment is formed of a hollow shaft (not shown), and two sheathed cords (not shown) are inserted into the hollow display shaft 25. One end of each of these sheathed cords is the first sheathed cord. And the second power supply terminal tongue pieces 21 and 22, and the other end is connected to a high frequency power supply (not shown).

The end of the discharge lamp on the pinch seal side in which the internal electrode 4 is sealed is attached to the lamp holder 20. That is, the first power receiving terminal 10 and the second power receiving terminal 11 formed on the outer surface of the bulb 2 face the first power supply terminal tongue piece 21 and the second power supply terminal tongue piece 22 on the lamp holder 20 side. When the lamp 1 is pushed from the opening side of the lamp holder 20, the first and second power supply terminal tongues 2
The holding pieces 222, 222 of the first and the second 22 respectively hold the first power receiving terminal 10 and the second power receiving terminal 11, and support the valve 2. Therefore, the discharge lamp 1 is fixed to the lamp holder 20.

In this case, since the first and second power supply terminal tongue pieces 21 and 22 are in electrical contact with the first power reception terminal 10 and the second power reception terminal 11, respectively, the internal electrode 4 and the external electrode 7 are connected to a high frequency power supply. You.

 The operation of the embodiment having such a configuration will be described.

When high-frequency power is supplied between the cold cathode 4 provided inside one end of the discharge lamp 1 and the external electrode 7, a glow discharge occurs between the internal cold cathode 4 and the external electrode 7 in the discharge space 3.

The glow discharge excites the xenon gas filled in the discharge space 3 and emits ultraviolet rays having a spectrum unique to the xenon gas. The short-wavelength light excites the phosphor coating 6, which generates visible light.

Light emitted from the phosphor coating 6 is emitted to the outside through the slit 9. For this reason, in addition to the fact that the bulb 2 is originally thin, the narrow slit portion 9 further restricts the band of light, so that the discharge lamp 1 emits light of a thin band like a needle.

Therefore, a display scale is indicated by the discharge lamp 1, and since this is illuminated, no special light source is required.

The lamp holder 20 is fixed to a rotating shaft 25, and when the rotating shaft 25 rotates, the lamp holder 20 is also integrally rotated. Therefore, the discharge lamp 1 attached to the lamp holder 20
Can also be turned together to show the display scale.

In the present embodiment, as shown in FIG. 3, the lead wire 42 of the
And a conical recess 5 is formed around the
Since a part of the conductive paste applied to 0 is also filled in the recess 5, the contact area between the lead wire 42 and the conductive paste is increased along the axial direction of the lead wire 42.

Therefore, the lead 42 and the conductive film, that is, the first
A large contact area with the power receiving terminal 10 is secured, and poor contact is eliminated.

It should be noted that the present invention is not limited to the above embodiment, and the discharge lamp of the present invention is not limited to the case where it is used as a display hand of an instrument, but includes a display device including a lamp support member, a display panel, a lamp holder and a housing. Can also be used as a light source.

Further, the discharge gas sealed in the bulb is not limited to only xenon, but neon,
A mixed gas containing at least one of argon and krypton may be sealed.

 Then, mercury may be sealed inside the bulb.

Further, the valve is not limited to a straight shape, and may be a bent shape.

[Effects of the Invention] As described above, according to the first aspect of the present invention, the concave portion is filled with the conductive material, and the conductive film is formed on the outer surface of the sealing portion by the conductive material. , The conductive coating makes great contact with the external lead wire,
Therefore, the contact area between the two is increased, so that the poor contact is eliminated, and the material to be filled into the concave portion and the material to be applied to the outer surface of the sealing portion can be extremely easily manufactured in which the same conductive material is used.

Further, according to the second aspect of the present invention, it is possible to provide a display device with high reliability of electrical connection.

[Brief description of the drawings]

1 shows an embodiment of the present invention, FIG. 1 is an exploded perspective view showing a case where a xenon glow discharge lamp is used as a pointer of an instrument, FIG. 2 is a plan view of a xenon glow discharge lamp, FIG.
The figure is a sectional view taken along the line III-III in FIG. 2, FIG. 4 is a sectional view taken along the line IV-IV in FIG. 2, and FIG. 5 is a sectional view taken along the line VV in FIG. . 1 ... discharge lamp, 2 ... bulb, 4 ... internal electrode, 42 ...
Lead wire, 210: crushed sealing portion, 10: conductive coating (first
, Recesses, 7, external electrodes, 8, light-shielding coatings, 9, light-transmitting slits, 20, bulb holders, 21, 22 power supply terminals.

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-57-63760 (JP, A) JP-A-2-80918 (JP, A) JP-A-3-261067 (JP, A) JP-A-3-3 261030 (JP, A) JP-B 43-17796 (JP, B1) Jiko 4-27086 (JP, Y2)

Claims (2)

(57) [Claims] 1. A valve having an electrode provided therein and a sealing portion formed at an end; and an outside having one end connected to the electrode and the other end led out through the sealing portion. A lead wire; a concave portion formed at a location where the external lead wire is led out of the sealing portion; and a conductive material is filled into the concave portion, and the conductive material is connected to the outer surface of the sealing portion. And a conductive film formed so as to be connected to the external lead wire by coating. 2. A display device using the low-pressure discharge lamp according to claim 1 as a light source.