JPH04280062A - Low pressure discharge lamp and low pressure discharge lamp device - Google Patents

Abstract

PURPOSE:To enhance light output. CONSTITUTION:An electric discharge gas is enclosed in a sealed glass bulb 1, a pair of inner electrodes 3, 4 are provided in this bulb 1, and at least a pair of outer electrodes 21, 22 are provided outside the bulb 1. Electrodes for forming a pair mutually are selected among the inner electrodes and the outer electrodes, and a plurality of electrode pairs are formed so that each pair thereof can generate independent discharge inside the bulb 1, and these plural electrode pairs are respectively connected to power sources 5, 23 so that these electrode pairs can conduct electric discharge simultaneously. Since a plurality of electrode pairs are connected to power sources to conduct electric discharge simultaneously with this constitution, the discharge gas is dispersed so as to enhance light output.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to low pressure discharge lamps such as fluorescent lamps and rare gas discharge lamps, and low pressure discharge lamp devices.

0002

[Prior Art] Recently, OA represented by facsimile etc.
Fluorescent lamps and xenon rare gas discharge lamps are increasingly being used as light sources for equipment, backlights for liquid crystal displays, and pointers for instruments. A conventional low-pressure discharge lamp of this type and its lighting method will be explained based on FIGS. 5 to 7.

FIG. 5 shows a schematic configuration of a cold cathode xenon rare gas discharge lamp used as a light source for facsimile machines.
1 is an arc tube bulb. This valve 1 has an outer diameter of 9.5m.
It consists of a glass tube with a total length of about 150 mm, and the inner surface is coated with a white phosphovanadate phosphor (Y(
A phosphor coating 2 made of P,V)O4:Dy) is formed, and internal electrodes 3 and 4 are sealed at both ends. Note that the internal electrodes 3 and 4 each use a cold cathode. When a cold cathode is used, there are advantages such as a simpler structure because no preheating means or heating electrodes are required, a longer life due to less thermal deterioration of the bulb and electrodes, and the ability to make the bulb thinner. .

The internal electrodes 3 and 4 are connected to a high frequency lighting circuit 5, and the high frequency lighting circuit 5 is configured to supply power such that the lamp current during stable lighting is 10 mA at a frequency of, for example, 30 KHz. It has become. Valve 1
Inside, xenon gas is sealed at 100 Torr.

In the case of such a cold cathode type xenon rare gas discharge lamp, when high frequency power is applied from the high frequency lighting circuit 5 to the internal electrodes 3 and 4, the internal electrodes 3 and 4 inside the bulb 1
A glow discharge occurs between the two, and this discharge excites the xenon gas to emit ultraviolet light, which is converted into white visible light by the phosphor coating 2 and emitted to the outside. In the case of the above lamp, the brightness at the center of the bulb is approximately 1570 cd/
m2. Next, another conventional low pressure discharge lamp will be explained based on FIG. 6.

The discharge lamp shown in FIG. 6 shows a schematic configuration of a cold cathode xenon rare gas discharge lamp used as a meter pointer, and the size and electrical characteristics of the lamp are the same as those in FIG. 5. In the case of this lamp, one internal electrode 11 is provided at one end of the bulb 1, and an external electrode 12 made of a band-shaped silver coating is provided along the axial direction on the outer surface of the bulb 1. A high frequency lighting circuit 5 is connected to the electrode 12 .

In the case of such a xenon rare gas discharge lamp,
When high-frequency power is applied from the high-frequency lighting circuit 5 between the internal electrode 11 and the external electrode 12, a glow discharge occurs inside the bulb 1, and this discharge excites the xenon gas to emit ultraviolet light, which is emitted from the phosphor. The light is converted into white visible light by the coating 2 and radiated to the outside. In the case of the above lamp, the brightness at the center of the bulb is approximately 2300 cd/m2. Furthermore, another conventional low pressure discharge lamp will be explained based on FIG. 7.

The discharge lamp shown in FIG. 7 is a xenon rare gas discharge lamp of a different construction used as a meter pointer, and in this case as well, the size and electrical characteristics of the lamp are the same as in the case of FIG. In the case of this lamp, external electrodes 21 and 22 made of a silver film or the like are provided on the outer surface of the bulb 1 and are opposed to each other and extend in a band shape along the axial direction. It is connected.

In the case of such a xenon rare gas discharge lamp,
When high frequency power is applied between the external electrodes 21 and 21 from the high frequency lighting circuit 5, a glow discharge occurs inside the bulb 1, and this discharge excites the xenon gas and emits ultraviolet rays, which are emitted by the phosphor coating 2. It is changed into white visible light and radiated to the outside. In the case of the above lamp, the brightness at the center of the bulb is approximately 3500 cd/m2.

The discharge lamps shown in FIGS. 5 to 7 above are all xenon gas low-pressure discharge lamps, and such discharge lamps have a property that the positive column is narrowed by the internal electrodes 3, 4, or 11. Therefore, the sunlight column becomes thinner. That is,
When internal electrodes are present, the brightness tends to be lower in the case of FIG. 6 than in the case of FIG. 7, and further in the case of FIG. 5 than in the case of FIG.

On the other hand, in the case of a mercury low-pressure discharge lamp in which mercury and a rare gas such as argon are sealed inside the bulb, the structure shown in FIG.
The case shown in FIG. 5 tends to be even brighter. This is due to the diffusion effect of mercury.

0012

[Problems to be Solved by the Invention] However, even with lamps having the above structures, as well as xenon discharge lamps and mercury discharge lamps, conventional lamps tend to lack brightness, and lamps with high brightness tend to be insufficient. It has been demanded. Therefore, the first problem of the present invention is that conventional lamps sometimes lack brightness.

On the other hand, for example, in the case of instruments installed in the driver's seat of a vehicle or the cockpit of an aircraft, the surrounding brightness may be extremely different, such as when it is exposed to direct sunlight during the day or when it is in the darkness at night. When lighting instruments in such usage environments, it is desirable to be able to dim them. The light control means detects the brightness of the surrounding area using a light sensor, and changes the frequency or voltage of the power applied to the lamp from the high-frequency lighting circuit accordingly, thereby adjusting the illuminance that illuminates the instrument according to the surrounding brightness. A structure that automatically adjusts is conceivable.

However, in the case of conventional lamps, the electrode structure is as shown in FIGS. 4 to 6, and as mentioned above, the maximum brightness is relatively low, so the difference between the maximum brightness and the minimum brightness is small, that is, The brightness ratio is 200:1 or less,
There is a problem that the brightness adjustment range, that is, the dimming range is narrow. In other words, the second problem of the present invention is that in the case of conventional lamps, the brightness is relatively low, so the dimming width is narrow.

The present invention was made based on the above circumstances, and its first object is to provide a low-pressure discharge lamp and a low-pressure discharge lamp device that can improve light output. be. A second object of the invention is to provide a low-pressure discharge lamp device that can expand the dimming range.

[0016]

[Means for Solving the Problems] The low pressure discharge lamp of the present invention includes:
The present invention is characterized in that a discharge gas is sealed inside a sealed glass bulb, a pair of internal electrodes are provided inside the bulb, and at least one pair of external electrodes is provided outside the bulb.

Further, the low pressure discharge lamp device of the present invention includes a sealed glass bulb filled with discharge gas, a pair of internal electrodes provided inside the bulb, and at least one pair of external electrodes provided outside the bulb. A plurality of electrode sets are formed by selecting pairs of electrodes from among the internal electrodes and external electrodes so that each generates an independent discharge within the bulb, and each of the plurality of electrode sets is connected to a power source. It is characterized in that a plurality of electrode sets are made to discharge at the same time.

Another low-pressure discharge lamp device of the present invention includes a sealed glass bulb filled with discharge gas, a pair of internal electrodes provided inside the bulb, and at least one pair of external electrodes provided outside the bulb. A plurality of electrode sets are formed by selecting pairs of electrodes from among the internal electrodes and external electrodes so that each generates an independent discharge within the bulb, and the power supplied to each of the plurality of electrode sets is adjusted. By connecting to a possible power source, it is possible to select discharge from one of these plurality of electrode sets, and by switching between these discharges and adjusting the power supplied during each set's discharge, it is possible to dim the amount of light emitted from the bulb. It is characterized by what it did.

[0019]

[Function] According to the low-pressure discharge lamp of the present invention, a pair of internal electrodes and at least one pair of external electrodes are provided, so if all these electrodes are used for discharge, the discharge gas will be diffused and the potential gradient will be balanced. As the solar column becomes larger, the light output increases. Furthermore, according to the low-pressure discharge lamp device of the present invention, since multiple electrode sets are connected to a power source and discharged simultaneously, the discharge gas is diffused and the potential gradients are balanced, the positive column becomes larger, and the light Output is improved.

Furthermore, according to another low-pressure discharge lamp device of the present invention, each of the plurality of electrode sets is connected to a power source whose supplied power can be adjusted, and discharge from any one of the plurality of electrode sets can be selected. Since the discharge is switched and the power supplied is adjusted during the discharge of each set, the amount of light emitted from the bulb can be dimmed, and in this case, the range of adjustment can be widened.

[0021]

Embodiment The present invention will be explained below based on a first embodiment shown in FIG. This embodiment shows the case of a xenon rare gas discharge lamp, and parts that may be the same as those of the conventional one will be described using the same numbers as in the case of FIGS. 5 to 7.

[0022] The arc tube bulb 1 has an outer diameter of 9.5 mm and a total length of 1.
It consists of a glass tube of about 50 mm, and the inner surface is coated with a white phosphovanadate phosphor (Y(P,V)O
A phosphor coating 2 made of 4:Dy) is formed. Internal electrodes 3 and 4 made of cold cathodes are provided at both ends of the bulb 1.
is sealed.

These internal electrodes 3 and 4 form a high frequency lighting circuit 5.
The high frequency lighting circuit 5 is connected to, for example, power having a frequency of 30 KHz. The bulb 1 is filled with xenon gas at 100 Torr.

Further, external electrodes 21 and 22 made of a silver coating or the like are provided on the outer surface of the bulb 1, facing each other and extending in a band shape along the axial direction. It is connected to the lighting circuit 23. This high-frequency lighting circuit 23 is also synchronized with the one high-frequency lighting circuit 5 to supply power having a frequency of, for example, 30 KHz.

In such a cold cathode type xenon rare gas discharge lamp, the high frequency lighting circuit 5 applies high frequency power to the internal electrodes 3 and 4 to generate a discharge between the internal electrodes 3 and 4, and also synchronizes with this. Then, another high frequency lighting circuit 23 applies high frequency power to the external electrodes 21 and 22 to generate a discharge between these external electrodes 21 and 22. In other words, two sets of discharge forms are generated simultaneously, and the total lamp current at this time is set to be 10 mA.

In such a xenon discharge lamp device, a glow discharge occurs inside the bulb 1 between the internal electrodes 3 and 4 and between the external electrodes 21 and 22, and this discharge excites the xenon gas and emits ultraviolet rays. This ultraviolet light is converted into white visible light by the phosphor coating 2 and radiated to the outside. In this case, since the positive column is diffused between the internal electrodes 3 and 4 and between the external electrodes 21 and 22, the positive column becomes thicker.
Therefore, the optical output is improved.

In the case of this embodiment, the size and electrical characteristics of the lamp are the same as those of the conventional lamp shown in FIGS. 5 to 7, but the luminance at the center of the bulb is 4000 cd/m2, which is brighter than the conventional lamp. Next, a second embodiment of the present invention will be described based on FIG.

This embodiment differs from the first embodiment in that the combination of electrodes for discharging is different. In this embodiment, one internal electrode 4 and one external electrode 21 are used as a set. The other internal electrode 3 and the other external electrode 22 are connected to a second high frequency lighting circuit 23 as another pair.

In the case of a xenon discharge lamp having such a configuration, two sets of discharge forms shown in FIG. 6 are performed at the same time, and as the positive column expands, the potential gradient becomes symmetrical. Therefore, the brightness at the center of the bulb is 6000 cd/
m2, making it brighter than before. Therefore, if the internal electrodes 3 and 4 and the external electrodes 21 and 22 are used simultaneously for discharge, the brightness will be improved.

[0030] In the above first and second embodiments, the case of a xenon low-pressure discharge lamp in which xenon alone is sealed in the bulb 1 has been explained, but a rare gas such as neon or krypton mixed with xenon may be used. This may also be the case with a discharge lamp.

Alternatively, a low-pressure mercury discharge lamp in which the bulb 1 is filled with mercury and a rare gas such as argon may be used. In the case of a mercury low-pressure discharge lamp, ultraviolet light is emitted by ionization and excitation of mercury atoms, so the two systems of discharge activate the ionization and excitation of mercury atoms, thereby increasing light output. Next, a dimming type low pressure discharge lamp device will be explained based on FIGS. 3 and 4. In this embodiment, a case will be described in which a low-pressure mercury discharge lamp is used, and the lamp structure shown in FIG. 3 may be the same as that in FIG.

The low pressure mercury discharge lamp of this example has an outer diameter of 8 mm.
A coating 2 made of a three-wavelength phosphor is formed on the inner surface of an arc tube bulb 1 having a total length of 250 mm, and mercury and argon are sealed inside the bulb 1 at a normal temperature of 20 Torr.

Internal electrodes 3 and 4 made of cold cathodes sealed at both ends of the bulb 1 are connected to a high frequency lighting circuit 5, and this high frequency lighting circuit 5 is equipped with a first controller 31 for power adjustment. The controller 31 for power regulation is, for example, a chopping device or a voltage control device. Therefore, the discharge of the internal electrodes 3 and 4 is controlled by the controller 31, so that the lamp current can be changed. External electrodes 21 and 22 provided on the outer surface of the bulb 1 are connected to another high frequency lighting circuit 23, and this high frequency lighting circuit 23 also has a second high frequency lighting circuit 23 for power adjustment.
This power adjustment controller 32 also includes, for example, a chopping device or a voltage control device. Therefore, the discharge of the external electrodes 3 and 4 is controlled by the controller 32, so that the lamp current can be changed.

In the dimmable low-pressure mercury discharge lamp device having such a configuration, the internal electrode 3 is connected by the high-frequency lighting circuit 5.
. 22 to generate a discharge. In other words, two sets of discharge forms are generated simultaneously, and the maximum brightness at this time is 19,000 cd/m2.

Then, when the second controller 32 is adjusted to gradually reduce the power supplied between the external electrodes 3 and 4, the discharge becomes gradually weaker, and the optical output gradually decreases as shown by the X zone in FIG.

When the second controller 32 is adjusted to stop the discharge between the external electrodes 3 and 4 and switch to discharge only between the internal electrodes 3 and 4, the maximum brightness at this time is 15,000 cd/
m2.

Furthermore, when the first controller 31 is controlled to gradually reduce the power supplied between the internal electrodes 3 and 4, the discharge becomes gradually weaker, and the light output gradually decreases as shown by the Y zone in FIG. When the control range by the first controller 31 reaches its lower limit, the second controller 32 is adjusted to switch to discharge between the external electrodes 3 and 4. External electrode 3
, 4, argon is emitted and the maximum brightness is approximately 750 cd/m2.

Furthermore, when the second controller 32 is adjusted to gradually reduce the power supplied between the external electrodes 3 and 4, the discharge becomes gradually weaker, and the light output gradually decreases as shown by the Z zone in FIG. This light control is possible up to about 10 cd/m2. However, since the light emission in the Z zone is argon light emission, the light color may shift to a pinkish color.

However, with the above dimming method, it is possible to achieve almost linear dimming up to a ratio of 1000:1, partly due to the increase in maximum brightness, and the dimming range is much wider than that of the conventional method. It becomes wider.

In the case of a low-pressure mercury discharge lamp with the above structure, if xenon gas is used instead of argon and mercury and xenon are sealed at 40 Torr, the light emission in the Z zone becomes xenon light emission, and the spectrum of xenon light emission is 147
nm, so color shift from mercury emission can be reduced.

Furthermore, the above-described dimmable low-pressure discharge lamp is not limited to mercury discharge lamps, but can also be implemented with xenon gas or other rare gas discharge lamps, as can be understood from the embodiments shown in FIGS. 1 and 2. . In this case, it goes without saying that the electrode set for the discharge that exhibits the maximum brightness may be selected, and the electrode sets for the discharge whose brightness decreases are sequentially switched for selective use.

[0042] In the above embodiment, the power source is a power source that supplies high-frequency power, but the present invention is not limited to this, and a normal commercial power source may be used, and the electrode is not limited to a cold cathode but may also be a hot cathode. It may be. Moreover, there may be multiple sets of external electrodes. The bulb is not limited to a straight tube shape, but may have a bent shape such as a U or W shape, and the cross-sectional shape of the bulb may be circular, elliptical, or oval. Furthermore, the inner surface of the bulb 1 may be free of the phosphor coating 2.

[0043]

As explained above, according to the low-pressure discharge lamp of the present invention, the discharge gas is diffused and the potential gradient is balanced by using all of the pair of internal electrodes and at least one pair of external electrodes. As a result, the optical output is improved.

Furthermore, according to the low-pressure discharge lamp device of the present invention, since a plurality of electrode sets are connected to a power source and discharged simultaneously, the discharge gas is diffused and the potential gradients are balanced, so that the light output is increased. improves.

Furthermore, according to another low-pressure discharge lamp device of the present invention, each of the plurality of electrode sets is connected to a power source whose supply power can be adjusted, and discharge from any one of the plurality of electrode sets can be selected. Since the discharge is switched and the power supplied is adjusted during the discharge of each set, the amount of light emitted from the bulb can be dimmed, and in this case, the range of adjustment can be widened.

[Brief explanation of the drawing]

FIG. 1 shows a first embodiment of the present invention, (a) is a configuration diagram of a xenon gas discharge lamp device, (b) is a diagram showing the configuration of a xenon gas discharge lamp device;
- Cross-sectional view taken along line B.

FIG. 2 shows a second embodiment of the present invention, (a) is a configuration diagram of a xenon gas discharge lamp device, (b) is a diagram showing the structure of a xenon gas discharge lamp device;
- Cross-sectional view taken along line B.

FIG. 3 shows a third embodiment of the present invention, (a) is a configuration diagram of a low-pressure mercury discharge lamp device, (b) is a line BB in (a)
Cross-sectional view of the line.

FIG. 4 is a characteristic diagram showing the condition of dimming in the same embodiment.

FIG. 5 is a configuration diagram of a conventional xenon gas discharge lamp device.

FIG. 6 is a configuration diagram of another conventional xenon gas discharge lamp device.

FIG. 7 shows still another conventional example, in which (a) is a configuration diagram of a xenon gas discharge lamp device, and (b) is a diagram showing the structure of a xenon gas discharge lamp device;
A cross-sectional view taken along line B.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Glass bulb, 2... Phosphor layer, 3, 4... Internal electrode, 5... First high frequency lighting circuit, 21, 22... External electrode,
23...Second high frequency lighting circuit, 31, 32...Power controller.

Claims (5)

[Claims] 1. A low-pressure discharge lamp characterized in that a discharge gas is sealed inside a sealed glass bulb, a pair of internal electrodes are provided inside the bulb, and at least one pair of external electrodes is provided outside the bulb. . 2. A discharge gas is sealed inside a sealed glass bulb, a pair of internal electrodes is provided inside the bulb, and at least one pair of external electrodes is provided outside the bulb, and a discharge gas is provided inside the bulb. Select pairs of electrodes from above to form multiple electrode sets so that each generates an independent discharge within the bulb, connect each of these multiple electrode sets to a power source, and discharge simultaneously with these multiple electrode sets. A low pressure discharge lamp device characterized by: 3. The low-pressure discharge lamp lighting device according to claim 2, wherein the plurality of electrode sets include one set of internal electrodes and another set of external electrodes. 4. A claim characterized in that the plurality of electrode sets are one set consisting of one internal electrode and one external electrode, and another set consisting of the other internal electrode and the other external electrode. 2
The low pressure discharge lamp device described in . 5. A discharge gas is sealed inside a sealed glass bulb, a pair of internal electrodes are provided inside the bulb, and at least one pair of external electrodes is provided outside the bulb, and a discharge gas is provided inside the bulb. Select pairs of electrodes from the above to form multiple electrode sets so that each generates an independent discharge within the bulb, connect these multiple electrode sets to a power supply whose power supply can be adjusted, and A low-pressure discharge lamp device characterized in that it is possible to select the discharge of any one of the electrode sets, switch these discharges, and adjust the power supplied during the discharge of each set, thereby making it possible to dim the amount of light emitted from the bulb. .