JPS6028155A - Small-sized metal vapor discharge lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a small metal vapor discharge lamp that is operated using a power source such as direct current that does not have polarity reversal.

[Technical background of the invention and its problems]

In recent years, from the viewpoint of energy conservation, the development of metal vapor discharge lamps with excellent luminous efficiency, such as metal halide lamps, which can be used in place of incandescent lamps with low luminous efficiency, has been actively promoted. These metal vapor discharge lamps use AC 100V or 200V at a commercial frequency of 50Hz or 60Hz.
It is customary to turn on the lamp using the general power supply (2) via a ballast, and the ballast is installed in a separate location from the discharge lamp. However, when considering it as an alternative to incandescent light bulbs, which are often used indoors in households and stores, it is essential that the lamp and ballast be integrated, and that the ballast be compact, lightweight, and inexpensive. be. However, it is considered difficult to satisfy the above conditions with the currently common ballast using a choke coil. In recent years, with the development of transistors, ICs, etc., it has become possible to construct an electronic circuit as a ballast that can satisfy the above conditions. Possible methods for such electronic circuits include DC lighting methods and high frequency lighting methods.
According to the high-frequency lighting method, a phenomenon called acoustic resonance occurs in a specific frequency band, which causes the arc to fluctuate and cause the lamp to go out. In particular, in the case of metal hashide lamps, the frequency band in which acoustic resonance occurs is extremely wide due to the shape of the arc tube, the enclosed material, etc., making high-frequency lighting methods inappropriate. therefore.

In particular, as an electronic ballast for metal halide lamps, the lighting method using a power source that does not have polarity reversal such as DC is the lighting method. During the development process, when a discharge lamp designed for conventional AC lighting, which has an electrode with a coil wound around the tip of the electrode shaft, was lit using a power source that did not have polarity reversal, one arc tube leaked and caused a defect. I discovered that there are many lamps that occur.

Moreover, it has been found that this phenomenon becomes even more severe in small lamps of 100 W or less, where the cathode and the wall of the arc tube are closer together. We further observed these phenomena by comparing them with AC lamps, even when the lamps were stable in steady state.

It has been found that when the lamp is lit with a power source that does not have polarity reversal, an arc spot is formed on the sealed end side of the cathode, and this spot may not migrate to the cathode tip.

It was found that most of the lamps that were left on for a long period of time in this state caused the rack as described above. On the other hand, in the case of AC single lighting, although discharge started from the sealed end side of the electrode immediately after starting, the arc spot in all lamps moved to the electrode tip in a short time, and no cracks occurred. This phenomenon is presumed to be due to the following reasons. That is, even in the case of an alternating current power source with no polarity reversal, the discharge starts immediately after starting in a state where the voltage is low, below 1 atm, and the electrical distance remains for a long time.

However, over an hour, the temperature inside the arc tube rose.

It can be around or even above atmospheric pressure. therefore.

In order for the discharge to remain stable, the well-known law pd
=const. (P is pressure, d is discharge distance), the arc spot moves from the electrode sealing end side to the electrode tip, and moves in the direction where the discharge distance d becomes shorter. This phenomenon is caused by the fact that in the case of alternating current, each electrode acts as both a cathode and an anode in each half cycle, so when it is an anode, the arc concentrates on the entire electrode and the tip of the electrode is also heated. However, as the temperature increases, the arc easily moves to the electrode tip.

When there is no polarity reversal, such as direct current, the arc forms a spot on the cathode side, concentrating only on a small portion of the sealed end of the electrode, and only that concentrated portion is heated. Moreover, since the coil group acts like a heat dissipation fin, the temperature at the tip of the electrode does not rise to a level sufficient to emit electrons even if the pressure inside the arc tube increases sufficiently.

Moreover, since there is no reversal of polarity, it is inferred that the arc may not move from the spot position once created unless some trigger occurs.

Therefore, an arc spot is generated on the sealed end side of the cathode,
Moreover, there is no migration to the cathode tip.

The approach and contact of the high-temperature arc with the wall of the arc tube continues for a long time, and as a result, devitrification and cracks occur on the wall of the arc tube.

Moreover, the fact that arcs can occur at the sealed end side or the tip of the pole means that the arc lengths are different, and if the arc lengths are different, the lamp voltage will also be different, so each time the lamp is lit, This also results in the inconvenience that the voltage is not constant. [Object of the Invention] The present invention has been made in consideration of the above circumstances.

A 100W lamp that has a long life and stable weight with no devitrification or cracks in the arc tube when lit with a single source that does not have polarity reversal, such as DC, and less fluctuation in lamp voltage.
The purpose of the present invention is to provide a small metal vapor discharge lamp of less than (Watt).

[Summary of the invention]

In the present invention, a cathode is formed by inserting a high melting point metal rod into both ends of a coil, that is, the tip side, and an electrode shaft into the sealed end, and an end where the high melting point metal rod and the electrode shaft are inserted. The coil has a structure in which a gap is formed inside the coil by arranging the parts apart from each other.

The length of the above-mentioned gap is Z) r, the total length of the coil is L, and the outer diameter of the coil is 1) 0+, ia),
The inner diameter of the coil is d (mm), p4 toe 9111
% When the diameter of the polar axis is d 1 (rnr, q) and the steady state discharge current is IL (anobea).

1.5 <,'l)/d≦4・・・・・・・・・
・ (]) 14 (-IL/Sho≦350 ・ ・ ・
(2), e≧1ノ/3・・・・・・・・・・・・・・・・・・
・・・－・・・Adding (3) by '(8) is considered heavy equipment.

[Embodiments of the invention]

The details of the present invention will be explained below with reference to the illustrated embodiments. Figure 1 shows the light emitting tube (1) of a 40W (Watt) class small metal hashed lamp.The light emitting bulb (2) is made of quartz glass and is formed into an almost spherical shape with a maximum inner diameter of about 8 mm. Argon gas 100 torr as gas,
A total of 2 mg of mercury and metal halides such as scandium iodide and thorium iodide are sealed, and 4' In
A pole (3) and a negative pole (4) are sealed facing each other with an interval of x. The cathode (4) is made by winding a tungsten wire with a wire diameter of about 0.1 and has a total length of 2 myn.

The outer diameter is 0.35 mm, the inner diameter d is 0.15 man (
D A high-melting point metal rod (61) made of, for example, tungsten is inserted into the tip side of the coil (5), and an electrode shaft (7) also made of tungsten is inserted into the sealed end side. The ends of the body (6) and the electrode shaft (7) that are inserted into the coil (5) are spaced apart from each other, thereby forming a gap (8) with a length of just one inch inside the coil. Also, the distance from the tip of the coil (5) to the rod-shaped body (6) is approximately 0.04 mm.
It is configured so that the dragon protrudes. In other words, the ratio D/d of the coil outer diameter to the coil inner diameter d is expressed by the above equation (1) 1
．． D/d satisfying 5≦D/d≦4 = 0.35 vrt/ 0.15 +ot=
2.

In addition, the relationship between the length l of the gap (8) formed in the coil (5) and the total length of the coil (5) is expressed by the above formula (3) l≦L
It is e −1 no/2, which satisfies /3.

On the other hand, It! The rod (3) is a tungsten wire with a ffS diameter of 0.06 myrr! The 80.19 mm tungsten wire is wound into a coil, and then the diameter is 0.22 mm.
It is constructed by winding the VNR tungsten electric wire 1ζII (9) into a double coil (10).
10) has a total length of 1.5 y and 7 m. The anode (3) and cathode (4) are sealed at both ends of the light-emitting sound bulb (2).
), (llb) hermetically sealed with molybdenum foil (
:12a), (12b) to the external lead m (1
3a) and (13b) respectively, and the arc tube (1
) is formed. Although not shown, the arc tube (1) is usually sealed within an outer tube with a cap attached to one end, and the external lead wires (13a) and (13b) are connected to the cap and terminal, respectively, to complete the lamp. is formed.

For example, a lamp with such a configuration is connected to an AC power source (14) via a DC lighting electronic circuit ballast (14) as shown in Figure 2.
Connected to 1 unit. It is equipped with a ballast (AC/I) C' converter (16) and a current detection circuit 07). α
υ is a starting circuit that applies a starting pulse voltage between the cathode (4) and the anode (3). By the above-mentioned ballast (1) and starting circuit (18).

The arc tube (1) has a discharge 'rW flow IL of 0.56 at steady state.
When A (ampere) is applied and the lamp is lit stably, the current density at the entrance surface of the lamp is:

Discharge current IL/(n diameter dl)2= 0.56A/ (
0,15i+x)" is 25, and the value is the above (2
) Formula 14≦11. /d ]”;, satisfies 350.

100 each with the above lighting device for the above 10 lamps.
As a result of several flashing tests, no phenomenon was observed that occurred from the base of the arc cathode (4) (the sealed end side of the electrode i!1lII (7)) during stable lighting.

The reason for this is that a gap (8) is provided in the cathode coil (5), so that the arc can flow through the cathode (4) at the time of starting.
) Even if it occurs at the base of the coil (5), the temperature easily rises because the mass of that part is smaller than that of a coil (5) that is completely filled with electrode shafts and has no voids, that is, its heat capacity is small. Therefore, the temperature of the cathode tip quickly rises to a temperature at which arcing is likely to occur.

As the ignition progresses to stable lighting, the metal inside the arc tube (1) evaporates and the vapor pressure rises, and the arc tries to shorten the distance as much as possible, eventually reaching both electrodes (3), [4]
) leading to a transition to an arc between the tips.

Therefore, during stable lighting, there is no arc generation point at the base of the cathode (4), so the quartz glass of the two arc tubes (IJ) will not be constantly heated in the center and cause devitrification and cracks.
A long life is obtained, and since the arc length does not change each time the lamp is lit, there is no problem that the rung voltage changes. Moreover.

Since the cathode (4) is provided with a coil (5),
The voltage is low, and by providing a void (8) in the coil, the mass can be reduced compared to an electrode that has the same appearance but the entire inside of the coil is filled with electrode shafts, so it can be used to change from glow discharge to arc discharge. Good transition to and excellent starting characteristics. Furthermore, since the arc is generated from the protruding tip of the rod-shaped body (6) at the tip of the cathode during steady lighting, there is also the advantage that the arc spot is stable.

Next, we will discuss the results of tests conducted to determine the range of preferred cathode structures. The test rung is a 40W metal hydrogen rung with the same structure as the above example, and its cathode (4)
The effect on Lang characteristics was investigated by changing only the structure of .

Table 3 shows the test contents and results, and the factors contributing to the variation of the cathode structure are the shaft diameter dIQ++i) of the electrode shaft (7);

Coil outer diameter D (mn), inner diameter d (mi), overall length L
(related) The length A (in) of the internal cavity (8) and the coil type (single layer and multilayer) are taken up, and the difficulty of transition from glow discharge to arc discharge is evaluated.

The starting characteristics and life characteristics were determined by comparing and considering the difficulty of transitioning the arc spot from the cathode root to the cathode tip. In addition, in the cathode shape used in this test, as can be seen from FIG. 1, the shaft diameter d1 of the electrode shaft (7) and the coil inner diameter d are substantially the same. Further, the entire length of the rod-shaped body (6) inserted into the tip side of the coil (5) and the length of the rod-shaped body (6) protruding from the coil (5) were all the same as those in the above embodiment.

Table ■ In Table ■, for the first group (tests 461 to 167), the length of the gap (8) provided in the coil is l = l am
and the ratio of the coil inner diameter d to the same outer diameter D
/d is set to a predetermined value of 2 to 2.5, and d and D are set to the value of this ratio, and the electrode axis (force axis diameter d1) is varied in various ways.

This result shows that when dl is in the range of 0.04 to 0.2, the arc spot can easily move to the cathode tip at the time of starting, as in the above example, and the transition from glow discharge to arc discharge is also good. , and there were no problems with the life characteristics.

On the other hand, in the case of dl = 0.22 (43), the electrode axis diameter dl is too large for the steady state discharge current IL = 0.56A, and the transition of the arc spot from the cathode root to the cathode tip is not smooth. 2 out of 3 are complete (no migration, the remaining 1 is also 10)
Even after 0 hours of lighting, there were arc spots at the base and arc tube cracks occurred. on the other hand.

On the other hand, in the case of dl = 0.02 (flat 7), the electrode axis diameter d1 is too small, and the wall of the arc tube becomes significantly blackened due to the scattering of tungsten from the electrode material during its life, resulting in a decrease in the luminous flux maintenance rate. Remarkable.

From this result, the diameter dl of the electrode shaft (7) is 0.04 to 0.
It was concluded that there should be two regulations.

The transition from glow discharge to arc discharge and the scattering of the electrode material depend not only on the diameter d1 of the electrode shaft (7), but also on the discharge current IL (5 ), the electrode shaft diameter dl(p+
From the above conclusion, the relationship between i) and discharge current IL (4) is expressed by a general formula.

IL (5)/d1 (lower limit value) = 0.56/(0,04)
2=350IL (A)/dl (upper limit), =0.
Because 56/(0,2)2 = 14.

i 4 <IL//c! 12≦350 ・・・・・・
・・・・・・・・・・・・・・・・・・・・・ (2
), so it can be seen that the relationship between IL and dI○ should satisfy the above equation (1) regardless of the input (watts).

Next, in the second group (Tests/168 to A15), the electrode shaft diameter d1 was changed to the lower limit of 0.04 mm and the upper limit of 0.2 mm in the range where the evaluation was good as described above. The length l of the coil inner cavity is set to 1 as in the case of the first group, and the relationship between the coil inner diameter d and the coil outer diameter is shown. The lamp used in the nine tests was the first one.
As shown in the figure, the coil inner diameter d is equal to the electrode shaft diameter dll, so the coil inner diameter d in the two tests was 0.04 mm and 0.04 mm, respectively.
This means that it is set to 2mm.

The result of Jin is d = 0.2rnmO is 0.3 deception≦D
In the range ≦0.8ttrm, and d = 0.04mm
The starting characteristics and life characteristics of the test tubes were good within the range of 0.06 mm≦D≦0.16 mm. On the contrary, d
= Q, for 2mm D = Q, for 9mm (shoulder 9
) and d = 0.04 for ram D = 0.2
mm (A14), D was too large compared to d, so the arc spot did not move to the cathode tip at startup, and even during stable lighting, there was an arc spot at the cathode root, and cracks were observed. Ta.

Furthermore, if D was large, that is, the coil (5) was large, so there was a problem that it was easy to remove it from the electrode shaft (7).

On the other hand, for d=0.2 gates, D=0.25 (A 1.1 )
and d = 0.04m+a and D = o, o5mm
(/1615), conversely, D is too small for d, so the action of the coil (5) itself is not sufficient (, glow,
Due to the high 7f pressure, the starting characteristics were poor, and there was a drawback in the transition of glow discharge to arc discharge.

In this way, when the coil inner diameter d = 0.2 mm, the range is 03≦D≦0.8 mm (7), and when d = 0.
04+++m is 0.06 mm≦]' r 0.16
Based on the result that a range of m is preferable, a general formula for the relationship between d and D, that is, the optimal range of D/d will be stated.

d = 0.2 0.3 am/ 0.2 mrn≦D/d≦0.8 m
m/0.2 mm so 1.5' knee D7d
≦4 Also, between d = 0.04, 0.06 mm70.04 mm'-D/d≦0.16
mm/0.04. Because it is mi.

1.5≦1)/d≦4.

In the end, the relationship between the coil inner diameter d and the coil outer diameter is 1.5≦
D/d≦4 ・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・ It turns out that (1) is sufficient.

Next, the third group (tests A616 to A22)
．． The second group of good combinations, i.e. equations (1) and (2
) The electrode shaft diameter was set to dx=0.04mv+.

0.15 mm and 0.2 mm, and the ratio D/d of the coil outer diameter to the coil inner diameter d: 2°0~
Set the value of D so that it is 25, and then
This is a case in which the length l of the cavity (8) in the coil is varied, assuming that L = 2 mm. This result is 1 (if the electrode axis diameter dl is any of the above values, the gap length l =
In the case of 0.7 mm + 1.5 m + x, the evaluation was good, but in the case of + 13 = ' 0.5 mm, the length of the gap was too short, that is, the inside of the coil (5) was not connected to the rod-shaped body (6) or the like. The part filled with the electrode shaft (7) is too long and has a large mass, which also increases its heat capacity. This means that the temperature rise at the tip of the cathode is insufficient or takes a long time, and the root of the cathode is heated during startup. In some cases, the arc spot generated during the process did not move quickly to the tip, and cracks occurred in the original light tube during its life.

Furthermore, the results of testing for the ratio of 1 mq between the height l of the coil internal cavity and the total length of the coil are shown in the fourth glue (1).
, Under the condition of adding 6'la to equation (2), the combination of the total length of the coil and the length l of the air gap in the coil is changed by 111j to obtain a result of 7/+! This is what I did.

5. Fruits and vegetables.

L = 2.51+rn, IJ = 1.0 +I+
! +'+, VL"' 0.4- (g test/l624
) L = 1. ．． 0, l = 0,4rnm, l/
L = 0.4- (Test j slender 26) II'J combination! ! j7 HQh characteristics + 'Jl? Life special] Life is good and 6 Puko.

Contrary to this.

I, = 2.5 n111. IJ = 0.8 ma
r, 19Ar = 0.32- (Test: ・, 6r y1
623) 1-4-1. Q +II#L, l-0,3r
=iiσ, l/L=0.3 (Trial 25) In the case of 1, that is, 6/L was 0.32 or less, a crank occurred in the light emission and evaluation.

Above j'A3. From the test results of the eK4 group, we found that if the length l of the void inside the coil is too long: 11゛・4, it will cause problems! The limit of f and ta is at the total length of the coil.

It can be seen that it is necessary to make l/L = '0.33 or more, that is, l≧J, /3 (3).

Note that N4'l:;r, (i is the cathode (4)) of each group in the l-h period and the form [,7te(, Kano 1st
As shown in the diagram, the chisel Jjli L, hoop in the coil.

For some of these test products, N4-(J), the coil type was changed to the initial layer type, for example, a double coil, to keep up with history.
Shin Seika, who conducted a substitute experiment, said that whether it was a coil type V or 11 coils, it was ``11% type'') 5 and changed to 1 song (・effect) / f628 changed to 162 , //629 is/
1), 1nl., and zfg30 structures are set to correspond to 163 and 1626, respectively. In other words, the -heavy coil has a good evaluation of 7 Rimono (41, yt6
2. 'z16.26) is good even with a multilayer coil (zfg 27°A628.yf630), and the one with a poor evaluation (A6.3) is a multilayer coil (Io2
9) was also defective.

In addition, the length of the high melting point metal rod (6) inserted into the tip side of the cathode coil (5), the length of the protrusion from the coil, etc. (
IL (2L) If all formulas (3) are satisfied, no particular restriction is recognized.

From the above results, the cathode (4) was packed by inserting the high melting point metal rod (6) from the tip of the coil (5) and the electrode shaft (7) from the sealed end, and .

The fitting ends of the high melting point metal rod and the electrode shaft are spaced apart from each other to form a gap (8) inside the coil, and this gap (8)
The length of is A(m+++), and the total length of =r is L(y+m
).

The outer diameter of the coil is (mm), and the inner diameter of the coil is d (+・
711! ')1 The diameter of the electrode shaft () on the sealed end side is dl (
mm), when the steady state discharge current is expressed as IL (ampere).

If the following conditions are satisfied: 1.5≦D/d≦4 14≦IL/d1”≦350 1≧L/3, both the starting characteristics and the lifespan characteristics will be good even when the lighting is used with a power source that does not have polarity reversal, such as DC. It has been found that an excellent lamp can be obtained.

Next, 4 above for a 100W metal halide lamp.
The same study as in the case of the OW lamp was conducted. A 100W metal halide lamp (d.d.c. lighting ballast and 1.1) with a steady state emission η-C?'J current (L) of 1.0, A, and a lamp input of 100W was used.

In this case as well, I confirmed that the same effect can be obtained by satisfying all of the above formulas (], ), (2), and (3).

In addition, a high secondary one-point gold j that is inserted into the tip side of the coil (5),
:R rod-shaped body (Q is tungsten containing thorium desulfide, which has better electron emissivity than tungsten, i.e., thorium tungsten). You can also do that.

6. In the above Example 1, a coil with the same lj9 diameter d was used over the entire length, but the present invention is not limited to this.
+ L formed thicker than the rolled part in (7)! ,
The present invention can also be applied to metal halide lamps, and similar effects can be obtained not only to metal halide lamps but also to other metal vapor discharge lamps such as high pressure mercury lamps and high pressure sodium 2 lamps.

〔Effect of the invention〕

More than i,) 1 has been reached”: According to non-invention, i ■ θI
When a platform is lit with a power source that does not have a reversal, such as L lighting, even if an arc occurs at the base of the pole during startup, it quickly moves to the tip, so it is caused by abnormal heating of the wall of the arc tube. Devitrification and cracking can be prevented, resulting in a longer life.

In addition, when the streetcar is lit, the arc is generated from the high melting point metal rod at the tip of the cathode, so the arc spot is stable and the arc length does not change each time the lamp is lit.
;Pressure remains constant. Moreover, since the cathode is equipped with a coil, does it glow? Since the E pressure is low and there is a void inside the coil, the mass can be reduced, so glow discharge is possible.
) The transition to arc discharge is also favorable, and effects such as being used for initial and 'IJJJ characteristics can be obtained.

4 Description of Drawings Figure 1 is a front view of the arc tube of a small metal halide lamp which is an embodiment of the present invention, and Figure 2 is a front view of the arc tube of the small metal halide lamp, which is an embodiment of the present invention. ... Arc tube pulp, (3) ... Anode.

(4);...Cathode, (5)...Cathode coil.

(6)... High melting point metal rod-shaped body, (7L-1 meeting! 1shi electrode tll+ + (14)... Ballast, (+61
... AC/l) C Konno Jinri.

(17)・'P-flow A full output circuit, θ~...Starting circuit agent Patent attorney Nori Chika Isuke (Poka 1 person)

Claims (1)

[Claims] An anode and a cathode are sealed opposite to each other at both ends of the arc tube pulp,
A small metal vapor discharge lamp of 100 W (watts) or less, which has an arc tube filled with a starting rare gas and a filler containing a small amount of mercury, and is lit by a power source with no polarity reversal. The cathode is formed by inserting a high melting point metal rod into the tip side of the coil and an electrode shaft into the sealed end side, and separating the fitting ends of the high melting point metal rod and the electrode shaft. The length of this gap is it (mm), the total length of the coil is L (in), the outer diameter of the coil is D (mm), and the inner diameter of the coil is d. (mJ, when the diameter of the electrode shaft on the sealed end side is dI (y++n), and the steady state discharge current is IL (ampere). 1.5≦D/d-4 14≦IL/d1≦350 1≧ A small metal vapor discharge lamp characterized by satisfying L/3.