JP2002260594A - Electrodeless discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the degradation in the start-up characteristic according to lapse of lit period. SOLUTION: There are provided an arc tube 4 in which a discharge gas is sealed in, and a coil 6 which, provided outside the arc tube 4, supplies an electric power to the discharge space in the arc tube 4. Inside the arc tube 4, a vessel 11 is provided which has an opening part 11a and a start-up assisting agent 10 is provided inside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeless discharge lamp.

[0002]

2. Description of the Related Art A conventional electrodeless discharge lamp has a light emitting tube (bulb) in which mercury as a discharge gas is sealed, and is disposed around the outer periphery of the light emitting tube. An arc tube with a metal mesh coated with a start-up aid on the surface to provide good starting characteristics even in dark places or cryogenic conditions It is known (JP-A-7-254391, etc.).

As a starting aid, cesium oxide having a small work function, for example, having a work function of about 1 eV, which easily emits electrons even when a small amount of photoelectrons or thermal energy is applied, is used.

[0004]

However, in such a conventional electrodeless discharge lamp, during operation, the starting aid is decomposed by the impact of electrons or ions and reacts with mercury in the arc tube to emit electrons. Since the compound becomes a hard and inactive compound, there is a problem that the starting characteristics deteriorate with the passage of the lighting time.

The present invention has been made to solve such a problem, and an object of the present invention is to provide an electrodeless discharge lamp capable of preventing the starting characteristics from being deteriorated with the elapse of the lighting time. .

[0006]

According to the present invention, there is provided an electrodeless discharge lamp comprising: an arc tube in which a discharge gas is sealed; and an electric power supply unit disposed outside the arc tube for supplying power to a discharge space in the arc tube. And a container having an opening inside the arc tube and a starting aid provided therein.

Thus, since the starting aid is provided in the container, the starting aid is less susceptible to the impact of electrons and ions during lighting, and thus the starting aid is decomposed and reacts with mercury in the arc tube. As a result, it is possible to suppress the formation of an inactive compound that does not easily emit electrons, so that it is possible to prevent the starting characteristics from deteriorating as the lighting time elapses.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electrodeless discharge lamp according to a first embodiment of the present invention, as shown in FIG. 1, has a pear-shaped bulb 2 having a phosphor film 1 formed on an inner surface thereof, and this bulb. 2
And a glass arc tube 4 having a stem 3 sealed at the end of the arc tube, and a power supply to a discharge space 5 in the arc tube 4 which is arranged around the largest diameter portion on the outer periphery of the arc tube 4. And a screw-type base 8 fixed to the end of the arc tube 4 with an adhesive 7.

In the arc tube 4, 5 m of mercury as a discharge gas
g and 50 Pa of argon gas are respectively sealed.

Further, one end of the arc tube 4 has a stem 3.
And a wire 9 made of nickel having the other end extending to the discharge space 5 and a starter attached to the other end of the wire 9 and made of, for example, cesium oxide on the inner surface as shown in FIG. Length 5 with auxiliary agent 10 attached
and a bottomed cylindrical container 11 having a diameter of 3 mm and a diameter of 3 mm.

The opening 11a of the container 11 has a large number of electrons and ions when the opening 11a is lit in the discharge space 5, and the inside of the discharge center 5a, which will be most susceptible to those impacts, will be described later.
It is preferable to be arranged at a distance from the discharge center space 5a so as not to be located at the same position.

The discharge center space 5a is defined as a first surface A (see FIG. 1) of the discharge space 5 of the arc tube 4 including one end surface of the coil 6, and a second surface including the other end surface of the coil 6. B (see FIG. 1) is the space with the highest discharge density.

[0013] opening 11a of the container 11, opening shape, for example circular, has an oval or polygonal shape, the opening total area is 1 mm ² 100 mm ^2. Preferably, the opening 11a faces the discharge center space 5a.

The material of the container 11 is a starting aid 10
When cesium oxide is used as a starting aid 10, for example, nickel,
In addition to metals such as iron, chromium, copper, brass, platinum, stainless steel, and niobium, ceramic and glass can be used,
In particular, it is preferable to use an inexpensive metal having high workability.

As the starting aid 10, in addition to the cesium oxide, an oxide of alumina, tin oxide, thorium oxide, barium oxide, a mixture of barium and strontium, or a mixture of barium, strontium and calcium And the like can also be used.

A lighting device 12 is connected to both ends of the coil 6, and a high-frequency current of, for example, 13.5 MHz flows therethrough.

Next, the starting characteristics of such an electrodeless discharge lamp were examined.

First, in the electrodeless discharge lamp according to the first embodiment of the present invention, as shown in Table 1, the opening 11a is located inside the discharge center space 5a, and the opening 11a is located at the discharge center. An electrodeless discharge lamp (hereinafter, referred to as "Example 1") facing the space 5a, the discharge center space 5a.
L (see FIG. 1) between the opening 11a and the opening 11a is 20 m
m, and the electrodeless discharge lamp (Example 2) in which the opening 11a faces the discharge center space 5a, the distance L between the discharge center space 5a and the opening 11a is 20 mm, and the opening 11
The electrodeless discharge lamp (Example 3) in which a is directed to other than the discharge center space 5a, the distance L between the discharge center space 5a and the opening 11a is 55 mm, and the opening 11a is directed to the discharge center space 5a. Electrodeless discharge lamp (Example 4), the distance L between the discharge center space 5a and the opening 11a is 55 m
m, and 30 electrodeless discharge lamps (Example 5), each having an opening 11a facing other than the discharge center space 5a, were produced. The starting time after 100 hours of lighting, the starting time after 1000 hours of lighting, and the starting time after 10000 hours of lighting of each of the manufactured electrodeless discharge lamps were examined. The result was obtained.

For comparison, in the electrodeless discharge lamp of Example 2, the container 11 was replaced with a plate-shaped metal net made of stainless steel having a length of 6 mm and a width of 6 mm, the surface of which was coated with a starting aid 10. The same experiment as in each of the above embodiments was performed on an electrodeless discharge lamp (conventional example).
The result as shown in was obtained.

In each of the examples and the conventional examples, 0.5 mg of cesium oxide was used as the starting aid 10. In each example, the total area of the openings 11a was 80 mm ² . In the example shown in FIG. 1, the distance L between the discharge center space 5a and the opening 11a is the shortest distance between the second surface B including the other end surface of the coil 6 and the opening 11a. Show. Further, in this experiment, in each of the examples, the direction of the opening 11a was "other than the discharge center space 5a".

The term "start time" as used herein refers to the time from when the power of the lighting device 12 is turned on until the start of light emission. However, the starting time shown in Table 1 indicates the longest starting time in each embodiment and the conventional example (the same applies to Table 2).

[0022]

[Table 1]

As is clear from Table 1, in the first embodiment,
For example, the start time after lighting for 100 hours was 6 msec, whereas the starting time after lighting for 10,000 hours was 50 msec. In Example 2, while the start time after 100 hours of lighting was 6 msec, for example, the starting time after 10000 hours of lighting was 10 msec. In Example 3 and Example 5, while the start time after 100 hours of lighting was all 20 msec, the starting time after 10,000 hours of lighting was both 30 msec, for example. In the fourth embodiment, the start time after the lighting of 100 hours is 7 msec, whereas the starting time after the lighting of 10,000 hours is 10 msec, for example.
c. On the other hand, in the conventional example, the starting time after 100 hours of lighting has elapsed is 6 msec.
The starting time after lighting of 00 hours was 950 msec.

As described above, in any of the first to fifth embodiments, the variation of the starting time with the lapse of the lighting time is smaller than the variation of the starting time with the lapse of the lighting time in the conventional example. It has been found that good starting characteristics can be obtained regardless of the lighting time. This is because, in any of Examples 1 to 5, since the starting aid 10 is provided in the container 11, the starting aid 10 is less susceptible to the impact of electrons and ions while the starting aid 10 is lit, and thus emits light. This is considered to be because it was possible to suppress the reaction with the mercury in the tube 4 to form an inactive compound that hardly emits electrons. on the other hand,
In the case of the conventional example, it is considered that this is because the starting aid 10 was decomposed by the impact of electrons or ions during the lighting, and became an inactive compound that hardly emits electrons by reacting with mercury in the arc tube 4.

In particular, when the opening time 11a of the container 11 is provided at a predetermined distance from the discharge center space 5a, for example, in the case of the second, third, fourth and fifth embodiments, the lighting time elapses. As can be seen from Table 1, the amount of change in the starting characteristics is smaller than the amount of change in the starting characteristics over the lighting time of Example 1 in which the opening 11a is located inside the discharge center space 5a. In addition, it was found that the amount of change in the starting characteristics with the lapse of the lighting time in the conventional example was smaller, and a better starting characteristic was obtained regardless of the lapse of the lighting time. This is because the opening 11a of the container 11 is not located in the discharge center space 5a where the number of electrons and ions is large in the discharge space 5 in any of the examples 2 to 5. It is considered that the number of electrons and ions that enter the container 11 through the opening 11a during lighting can be suppressed, and thus the starting aid 10 can be made more difficult to receive the impact of electrons and ions. Can be

Further, among Examples 2 to 5, the start-up time of Examples 2 and 4 in which the opening 11a faces the discharge center space 5a is the same as in Examples 3 and 4, as is clear from Table 1. It was found that the starting time was shorter than that in Example 5. This is because in both cases of Example 2 and Example 4, since the opening 11a of the container 11 is directed to the discharge center space 5a where the number of electrons and ions is large, the starting auxiliary agent is turned on after the power is turned on. This is considered to be because electrons emitted from 10 could be efficiently supplied to discharge center space 5a having the highest discharge density.

Next, the reason why the total opening area of the opening 11a of the container 11 is specified to be 1 mm ² or more and 100 mm ² or less will be described.

The total area of the opening 11a is 95 mm.
² (Example 6), 100 mm ² (Example 7), 105 mm
Thirty electrodeless discharge lamps each having the same configuration as in Example 2 except that various changes were made to ² (Example 8) and 120 mm ² (Example 9) were produced. The starting time after 100 hours of lighting, the starting time after 1000 hours of lighting, and the starting time after 10000 hours of lighting of each of the manufactured electrodeless discharge lamps were examined. The result was obtained.

As evaluation criteria, from the practical viewpoint, those with a start time of 50 msec or less after a lapse of 10,000 hours of lighting were evaluated as “good”, and those with a start time exceeding 50 msec were evaluated as “bad”.

[0030]

[Table 2]

As is clear from Table 2, the starting time after 100 hours of lighting is 6 msec in Example 6, for example, in which the total area of the opening 11a is 100 mm ² or less. Starting time of 11
msec, and in Example 7, the starting time after 100 hours of lighting was 6 msec, whereas the starting time after 10000 hours of lighting was 12 msec. on the other hand,
The total opening area of the opening 11a is more than 100 mm ^2.
while the start time after 10000 hours of lighting is 60 msec, and in Example 9 the start time after 100 hours of lighting is 5 msec, the starting time is 5 msec.
The starting time after lighting for 0000 hours was 100 msec. By defining the total opening area of the opening 11a of the container 11 to be 100 mm ² or less in this way, it was found that the above evaluation criteria were satisfied and the amount of change in the starting time with the passage of the lighting time could be suppressed. . This is because, for example, in the case of the second embodiment, the sixth embodiment, and the seventh embodiment in which the total opening area of the opening 11a is 100 mm ² or less, the total opening area of the opening 11a is small. It is considered that this is because electrons and ions are less likely to enter the container 11 through the opening 11a, so that the starting aid 10 can be prevented from being impacted by electrons and ions. On the other hand, the total area of the openings 11a is 100 m.
For example, in the case of Examples 8 and 9 exceeding m ² , since the total opening area of the opening 11a is large, electrons and ions in the discharge space 5 easily enter the container 11 from the opening 11a during lighting, It is considered that this is because the starting aid 10 was impacted by the invading electrons and ions.

The total area of the openings 11a is 1 mm.
^If it is less than ² , it is difficult to cause the starting aid 10 to adhere to the inner surface of the container 11 in the manufacturing process, which is not practically preferable.

As described above, according to the configuration of the electrodeless discharge lamp according to the first embodiment of the present invention, the starting aid 1
Since the starting auxiliary agent 10 is provided in the container 11, the starting auxiliary agent 10 is less susceptible to the impact of electrons and ions during lighting, so that the starting auxiliary agent 10 is decomposed and reacts with mercury in the arc tube 4 to emit electrons. Can be suppressed from becoming an inactive compound which is difficult to release, so that the starting characteristics can be prevented from deteriorating as the lighting time elapses.

In particular, the container 11 is so arranged that its opening 11a is not located in the discharge center space 5a of the discharge space 5.
By being arranged in the arc tube 4, the starting aid 1
0 is less susceptible to the impact of electrons and ions, and the starting characteristics can be further prevented from deteriorating as the lighting time elapses.

Further, since the opening 11a of the container 11 faces the discharge center space 5a, electrons emitted from the starting aid 10 can be efficiently supplied to the discharge center space having a high discharge density. , Good starting characteristics can be obtained.

Next, an electrodeless discharge lamp according to a second embodiment of the present invention has the same basic structure as the electrodeless discharge lamp according to the first embodiment of the present invention. 3
As shown in FIG. 1, a cylindrical bulb 1 having a phosphor film 1 formed on an inner surface thereof and cylindrical hollow portions 13 formed on both ends.
A glass arc tube 16 having a bulb 4 and a stem 15 sealed to the tip of one hollow portion 13 of the bulb 14;
It is arranged around the inner periphery of the hollow portion 13 of the valve 14,
In addition, two different coils 18 for supplying electric power to the discharge space 17 in the arc tube 16 are provided.

In FIG. 3, reference numeral 19 denotes a base.

In the arc tube 16, one end is attached to the other end extending to the discharge space 17 of the wire 9 sealed in the stem 15, and a starting aid (not shown) is attached to the inner surface. The bottomed cylindrical container 11 is disposed.

The container 11 has an opening 11 a having a first surface A including one end surface of the coil 18 in the discharge space 17.
(See FIG. 3) and a second surface B (see FIG. 3) including the other end surface of the coil 18 so that this discharge is not located in the two discharge center spaces 17a and 17b having a donut shape. They are arranged apart from the central spaces 17a, 17b. The opening 11a faces one discharge center space 17b.

As described above, in the configuration of the electrodeless discharge lamp according to the second embodiment of the present invention, similarly to the electrodeless discharge lamp according to the first embodiment of the present invention, the starting aid is made of a container. Since the starting auxiliary agent is provided inside the starting lamp 11, the starting auxiliary agent is less susceptible to the impact of electrons and ions during lighting, so that the starting auxiliary agent is not easily decomposed and reacts with mercury in the arc tube 16 to emit electrons. Since the active compound can be suppressed, the starting characteristics can be prevented from deteriorating as the lighting time elapses.

Next, the electrodeless discharge lamp according to the third embodiment of the present invention has the same basic structure as the electrodeless discharge lamp according to the first embodiment of the present invention. 4
As shown in FIG. 1, a substantially spherical bulb 21 having a phosphor film 1 formed on an inner surface and a hollow section 20 having a donut shape in a cross section and a central portion of the hollow section 20 of the bulb 21 (discharge described later) An arc tube 23 made of glass having a stem 22 sealed at an end of a part of the space 24, and an orifice 23 arranged on the inner periphery of the hollow portion 20 of the bulb 22 and supplying electric power to the discharge space 24. The difference is that a coil 25 is provided.

In FIG. 4, reference numeral 26 denotes a base.

In the arc tube 23, one end is attached to the other end extending to the discharge space 24 of the wire 9 sealed in the stem 22, and a starting aid (not shown) is adhered to the inner surface. The bottomed cylindrical container 11 is disposed.

The container 11 has an opening 11 a having a first surface A (see FIG. 4) including one end surface of the coil 25 in the discharge space 5 and a second surface B including the other end surface of the coil 25.
(See FIG. 4). The respective discharge center spaces 24a, 2a are not located in the donut-shaped discharge center space 24a and the columnar discharge center space 24b, respectively.
4b. In addition, this opening 1
1a is directed to a cylindrical discharge center space 24b.

As described above, in the configuration of the electrodeless discharge lamp according to the third embodiment of the present invention, similarly to the electrodeless discharge lamp according to the first embodiment of the present invention, the starting aid is made of a container. Since the starting auxiliary agent is provided inside the starting tube 11, it is difficult for the starting auxiliary agent to receive the impact of electrons and ions during lighting, and therefore, the starting auxiliary agent is not easily decomposed and reacts with mercury in the arc tube 23 to emit electrons. Since the active compound can be suppressed, the starting characteristics can be prevented from deteriorating as the lighting time elapses.

In each of the above embodiments, the opening 11
Although the description has been given of the case where the cylindrical container 11 having a single bottom is used, the external shape of the container 11 may be spherical or polygonal in addition to the cylindrical shape. The same effect as above can be obtained even when a container having However, when there are a plurality of openings 11a, the “total opening area” here means each opening 1
1a shows the total sum of the opening areas.

Further, in the above-described embodiment, the case where one container 11 is arranged in the arc tubes 4, 16, and 23 has been described, but a plurality of containers 11 are arranged in the arc tubes 4, 16, and 23. Even in this case, the same effect as described above can be obtained.

[0048]

As described above, the present invention can provide an electrodeless discharge lamp capable of preventing the starting characteristics from deteriorating as the lighting time elapses.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of an electrodeless discharge lamp according to a first embodiment of the present invention.

FIG. 2 is a front sectional view of a container used in the electrodeless discharge lamp.

FIG. 3 is a partially cutaway front view of an electrodeless discharge lamp according to a second embodiment of the present invention.

FIG. 4 is a partially cutaway front view of an electrodeless discharge lamp according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Phosphor film 2,14,21 Bulb 3,15,22 Stem 4,16,23 Arc tube 5,17,24 Discharge space 5a, 17a, 17b, 24a, 24b Discharge center space 6,18,25 Coil 7 Adhesion Agent 8 base 9 wire 10 starting aid 11 container 11a opening 12 lighting device 13,20 hollow part 19,26 base

Claims (4)

[Claims] An arc tube having a discharge gas sealed therein;
A coil disposed outside the arc tube and supplying power to a discharge space in the arc tube, wherein the arc tube has an opening, and a container provided with a starting aid therein. An electrodeless discharge lamp, which is arranged. 2. The discharge center space surrounded by a first surface including one end surface of the coil and a second surface including the other end surface of the coil in the discharge space. 2. The electrodeless discharge lamp according to claim 1, wherein the electrodeless discharge lamp is not located inside the discharge lamp. 3. The electrodeless discharge lamp according to claim 2, wherein an opening of the container faces the discharge center space. 4. The electrodeless discharge lamp according to claim 1, wherein a total area of the openings is 1 mm ² or more and 100 mm ² or less.