JPH056758A - High frequency lighting type discharge lamp and high frequency lighting device for discharge lamp - Google Patents

Abstract

PURPOSE:To provide a high frequency lighting type discharge lamp in which a positive column is stabilized and the profile of light emission is made clear in a lamp lighted at a high frequency. CONSTITUTION:A bulb 2 in which a discharge gas is sealed, a main electrode 3 provided on one end of the bulb inner part and connected to a high frequency power source, and an auxiliary electrode 6 provided on the other end of the bulb inner part but never connected to the power source are provided. A high frequency electric field is generated in the bulb 2 by the high frequency power outputted from the main electrode 3 to generate a discharge between the main electrode 3 and the auxiliary electrode 6. According to such a lamp, a positive column is collected to the auxiliary electrode, the profile of the positive column is made clear, and no fluctuation is caused.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency lighting cold cathode or hot cathode low-pressure discharge lamp for exciting mercury or a rare gas by a high-frequency electric field to emit light, and a high-frequency lighting device for a discharge lamp.

[0002]

2. Description of the Related Art Recently, attempts have been made to use a discharge lamp filled with xenon gas as a display needle in a display panel of a measuring instrument or an electric instrument.

A xenon discharge lamp used as such an indicator needle has hitherto been, as shown in FIGS. 5 and 6,
By forming the arc tube bulb 51 with an extremely thin hollow glass tube having an inner diameter of, for example, about 2 mm to 3 mm, a long and narrow discharge space is formed in the bulb, and an internal electrode (main electrode) 52 is provided at one end of the bulb 51. At the same time, a strip-shaped external electrode 53 is provided on the outer surface of the bulb 51 along the axial direction, and a phosphor coating 54 is provided on the inner surface of the discharge space. The internal electrode 52 uses a cold cathode having excellent life characteristics, and the cold cathode 52 is sealed to the sealing portion 56 by the lead wire 55. The discharge space is filled with a mixed gas containing mercury, xenon Xe, or xenon as a main component, as well as neon, krypton, argon, or the like.

The internal electrode 52 and the external electrode 53 are connected to a high frequency power source 12 such as a high frequency oscillator.
By applying high-frequency power between the internal electrode 52 and the external electrode 53, a discharge due to a high-frequency electric field is generated in the discharge space, the xenon gas is excited by this positive column to emit ultraviolet light, and this ultraviolet light is used as a phosphor. The film 54 is converted into visible light and emitted to the outside. Incidentally, 60, 6
Reference numeral 1 denotes the internal electrode 52 and the external electrode 53 which are connected to the high frequency power source 12
Is a terminal portion for electrically connecting to.

A light-shielding film 57 made of synthetic resin is formed on the outer surface of the bulb.
The thin strip-shaped light transmission slit 58 extending in the axial direction 1 is removed, and light is emitted from the elongated strip-shaped light transmission slit 58. Therefore, this lamp is an aperture lamp,
For this reason, the light emitting portion that serves as a display needle has an extremely thin needle shape.

In such a lamp, one end of a bulb 51 is attached to a rotary shaft of a meter (not shown), and when the rotary shaft is rotated, the lamp is also swung integrally.
Such a lamp has a merit that it has a function as a display needle, and that the lamp itself emits light and illuminates the display scale, so that no special illumination is required.

[0007]

However, in the above-mentioned conventional lamp, the internal electrode 52 is provided at one end inside the bulb and the strip-shaped external electrode 53 along the axial direction is provided on the outer surface of the bulb. High frequency power is supplied from the high frequency power supply 12 to the external electrode 53. In the case of such a lamp structure, the bulb 51
It is necessary to form a special external electrode 53 on the outside of the electrode. Further, since the external electrode 53 is formed by applying a conductive paste in a strip shape along the valve axial direction, the external electrode 5
It takes time and effort to form 3, and there is a concern that other members may come off when they come into contact with the external electrode 53. Further, since the external electrode 53 formed in a strip shape along the bulb axis blocks light, the surface provided with the external electrode 53 cannot be used as an effective light emitting surface, and the direction of use of the lamp is directional. May occur, and the direction of use may be restricted.

Under these circumstances, there is a demand for eliminating external electrodes. By the way, if a rare gas such as mercury or xenon is filled in the sealed space and this space is placed in an atmosphere of a high frequency electric field, the mercury or the rare gas described above can be eliminated even if there is no special external or internal electrode due to the condition of the high frequency electric field. It is known that gas is excited to emit ultraviolet light.
Therefore, if such a principle is used, a special external electrode can be omitted.

Therefore, the present inventors set the valve diameter to 3.0.
mm, the bulb length is 100 mm, in the cathode low-pressure mercury discharge lamp in which mercury and argon are sealed in the bulb, the external electrode is omitted, and the high frequency power source is connected only to the internal cold cathode sealed at one end of the bulb. When a high frequency of 50 Kz was applied to the cold cathode at 1000 V, for example, it was confirmed that mercury was excited inside the bulb to emit ultraviolet rays.

However, in the case of such a structure, the outline of the positive column is blurred in the bulb, it is difficult to obtain a positive column having a sharp profile, and the positive column fluctuates and flickers. . If the outline of the positive column is blurred, the light emitted from the light transmitting slit 58 may not be sharp, and the emission shape of the pointer may be blurred.

The present invention has been made in view of the above circumstances. In a lamp designed to be lit at a high frequency without using a special external electrode, a high frequency lighting type in which the positive column is stable and the contour of light emission is clear. It is intended to provide a light lamp.

[0012]

A high-frequency lighting discharge lamp according to the present invention comprises a bulb filled with a discharge gas, a main electrode provided at one end inside the bulb and connected to a high-frequency power source, and another inside the bulb. An auxiliary electrode which is provided at an end and is not connected to a power source, and a high-frequency electric field output from the main electrode is used to generate a high-frequency electric field in the bulb to cause discharge between the main electrode and the auxiliary electrode. It is characterized by having done.

The high-frequency lighting device for a discharge lamp according to the present invention comprises:
A discharge lamp having a main electrode at one end inside the bulb filled with discharge gas and an auxiliary electrode at the other end; and a high frequency electric power connected to the main electrode to supply high frequency power to the main electrode to generate a high frequency electric field in the bulb. It is characterized by comprising a high frequency power source for generating a discharge between the main electrode and the auxiliary electrode in the bulb by generating the discharge.

Further, in another lighting device of the present invention, a discharge lamp having a pair of auxiliary electrodes which are not connected to a power source in a bulb filled with a discharge gas, and a high-frequency electric field is applied to the discharge lamp so that the auxiliary electrode is provided. And a high-frequency electric field applying means for generating a discharge therebetween.

[0015]

According to the present invention, in any case, discharge is generated at the auxiliary electrode (floating electrode) provided at the end of the bulb and not connected to the power source, and the positive column is attracted, so that the positive column is gathered at this auxiliary electrode. As a result, the outline of the positive column becomes sharp and no fluctuation occurs.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIGS. 1 to 3 on the basis of an embodiment applied to a cold cathode fluorescent lamp used for a display needle of an instrument. In the figure,
Reference numeral 1 denotes a bulb of a cold cathode fluorescent lamp used as a display needle, which is formed of, for example, a glass tube having an outer diameter of 2.5 mm and a total length of about 100 mm, and has a substantially needle-like shape as a whole. The interior of this bulb 1 forms an elongated discharge space 2. A cold cathode 3 is sealed as an internal electrode, that is, a main electrode at one end of the bulb 1. The cold cathode 3 is connected to a lead wire 5 that hermetically penetrates a sealed end 4 of the bulb 1. There is.

As shown in detail in FIG. 3, the cold cathode 3 has an electrode head 31 made of, for example, nickel, zirconium-aluminum alloy or the like, and the electrode head 31 has, for example, a cylindrical shape. This cylindrical electrode head 31
The outer diameter of the electrode is, for example, about 1 mm. Inside the cylindrical electrode head 31, a lanthanide-based rare earth element such as lanthanum boride is suitable as an electron-emitting substance (emitter).
32 is filled. Such an electrode head 31 is
The opening at one end faces the discharge side, and the other end is connected to the lead wire 5. As the lead wire 5, a Dumet wire having a wire diameter of about 0.5 mm is used.

An auxiliary electrode 6 of the present invention is provided on the tip portion 7 of the bulb 1. The auxiliary electrode 6 may be any conductive wire, but for example, a Dumet wire having a wire diameter of about 0.5 mm is used. This auxiliary electrode 6 is called a floating electrode because it is not connected to a power source as described later, and its inner end face is exposed to the discharge space 2 and its outer end is exposed to the outside. The outer end of the auxiliary electrode 6 may not be exposed from the tip of the bulb 1. The valve tip 7 has a substantially spherical shape. In the bulb 1, a phosphor coating 8 is formed facing the discharge space 2. Further, the valve 1 is filled with a predetermined amount of mercury and argon gas.

A light-shielding coating 9 is formed on the outer surface of the bulb 1. The light-shielding film 9 has the components of carbon, epoxy resin and adhesive, and covers the outer surface of the bulb 1. In this case, the light-transmitting slit portion 10 without the light-shielding coating 9 is formed along the axial direction of the bulb. Therefore, this lamp emits light to the outside only through the light-transmitting slit portion 10, and therefore The fluorescent lamp has an aperture shape. The fluorescent lamp thus configured is attached to a lamp holder (not shown) and is connected to the pointer shaft of the meter.

The internal electrode 2 sealed at one end of the valve 1 is connected to the high frequency power source 12. That is, the sealing portion 4 formed at one end of the bulb 1 is provided with a terminal 11 for power supply connection, and the lamp is connected to a high frequency power supply 12 such as a high frequency oscillator via the terminal 11. In this case, the auxiliary electrode 6 sealed to the other end 7 of the bulb 1 is not connected to the power source 12 and thus serves as a floating electrode.

The operation of the embodiment having such a configuration will be described. When a high frequency power of, for example, 1000 V and 50 Kz is supplied to the lamp from a high frequency power source 12 such as a high frequency oscillator, this high frequency power is supplied to the discharge space 2 from the internal electrode 3 sealed at one end of the bulb 1, and glow discharge occurs in the discharge space 2. Occurs. This glow discharge excites mercury to emit ultraviolet rays, which are converted into visible light by the phosphor coating 8 deposited on the inner surface of the bulb 1. This visible light is emitted to the outside through the light transmitting slit portion 10 of the light shielding film 9. Therefore, since the bulb 1 is originally thin and the slit portion 9 presents an even narrower band of light,
This lamp is suitable for indicating a display scale as a display needle.

Since the auxiliary electrode 6 is provided at the other end 7 of the bulb 1 which produces such high-frequency discharge, electrons or ions are more likely to be concentrated on the auxiliary electrode 6 as compared with the case where the auxiliary electrode is not present, and The discharge will occur between the internal electrode 3 and the auxiliary electrode 6.

Therefore, the tips of the positive columns are gathered on the auxiliary electrode 6, the shape of the arc is stable, the contour is clear, and the fluctuation does not occur. Therefore, the emission form is stable, and the occurrence of flicker can be prevented.

In particular, in the case of this embodiment, the surface area of the auxiliary electrode 6 exposed to the discharge is made smaller than the surface area of the internal electrode 3 facing the discharge space, so that the positive column is closer to the auxiliary electrode 6 side than to the internal electrode 3 side. Since the luminous flux on the side of the tip portion 7 becomes thin when used as a pointer, it emits light like a pointer and is convenient for use as a support needle. This is particularly effective when the light shielding film 9 is not provided.

Further, since the tip portion 7 sealing the auxiliary electrode 6 has a spherical shape, this portion has a lens function,
Since the light is diffused, the brightness at the tip is increased, and a good light emission form can be obtained as a pointer.

In the above embodiment, the internal electrode 3 sealed at one end of the valve 1 is electrically connected to the high frequency power source 12, but the present invention is not limited to this. That is, the high frequency discharge can generate the discharge in the bulb 1 only by placing the bulb 1 in the high frequency electric field 20, as in the other embodiment shown in FIG. Therefore, the valve 1 is housed in a predetermined space such as a housing 21 made of an electrically conductive material, and the housing 21 is connected to the high frequency power source 12, so that the atmosphere around the valve 1 is changed to the high frequency electric field 20.
By doing so, it is possible to emit light inside the bulb 1.
Even in such a case, the auxiliary electrodes (floating electrodes) 25, which are not connected to the power source, are provided at both ends of the valve 2,
By providing 26, these auxiliary electrodes 25, 26
Since the positive columns are concentrated between them, the discharge is stabilized and the outline of the light emission becomes clear.

Further, in the present invention, the gas sealed in the bulb is not limited to mercury and argon, but is mainly xenon or xenon, and neon, argon,
A mixed gas in which at least one kind such as krypton is mixed may be enclosed. Further, it may be a lamp in which the fluorescent film is not provided on the inner surface of the bulb 2. Furthermore, the valve is not limited to a linear shape, but may be a bent shape.

[0028]

As described above, according to the present invention, since the auxiliary electrode (floating electrode) which is not connected to the power source is provided at the end of the bulb, a discharge is generated in this auxiliary electrode and the positive column is used for this auxiliary electrode. Since the light is focused on the electrode, the outline of the positive column becomes clear, and fluctuation does not occur. Therefore, the discharge is stabilized and the variation in the light emission is reduced.

[Brief description of drawings]

FIG. 1 is a perspective view of a cold cathode fluorescent lamp used as a pointer of a meter showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state of being connected to a power source in the embodiment.

FIG. 3 is an enlarged sectional view showing a main part of the embodiment.

FIG. 4 is a cross-sectional view showing a state in which the power source is connected to another embodiment of the present invention.

FIG. 5 is a perspective view of a conventional xenon discharge lamp.

FIG. 6 is a cross-sectional view showing a state of being connected to a conventional power source.

[Explanation of symbols]

1 ... Xenon cold cathode fluorescent lamp bulb, 2 ... Discharge space, 3 ... Internal electrode, 6, 25, 26 ... Auxiliary electrode, 8 ... Fluorescent film, 12 ... High frequency power source.

Claims (4)

[Claims] 1. A valve having a discharge gas sealed therein, a main electrode provided at one end inside the valve and connected to a high-frequency power source, and an auxiliary electrode provided at the other end inside the valve and not connected to a power source. A high-frequency lighting discharge lamp, wherein a high-frequency electric field output from the main electrode is used to generate a high-frequency electric field in the bulb to generate a discharge between the main electrode and the auxiliary electrode. 2. The surface area of the auxiliary electrode, which is not connected to the power source, exposed in the bulb is smaller than the surface area of the main electrode exposed in the bulb.
High frequency lighting discharge lamp. 3. A discharge lamp in which a main electrode is provided at one end and an auxiliary electrode is provided at the other end inside a bulb filled with a discharge gas, and a high-frequency power is supplied to the main electrode to supply high-frequency power to the main electrode. A high-frequency lighting device for a discharge lamp, comprising: a high-frequency power source for generating a discharge between the main electrode and the auxiliary electrode in the bulb by generating a high-frequency electric field therein. 4. A discharge lamp provided with a pair of auxiliary electrodes which are not connected to a power source in a bulb filled with a discharge gas, and a high frequency electric field application for generating a discharge between the auxiliary electrodes by applying a high frequency electric field to the discharge lamp. A high-frequency lighting device for a discharge lamp, comprising: