JPS5851457A - Miniture metal halide lamp - Google Patents

Abstract

PURPOSE:To improve the spectrum distribution and the service life characteristic, by making the cross-section at the electrode sealing section within the specific range against the lamp power while making the ratio between the inner end section distance of the light emission tube and the entire length withing the specific range thus reducing the heat transmission loss. CONSTITUTION:The electrode sealing section 2 is formed at both ends of the spherical section 1 then the electrode 3 and the lead wire 5 are connected to the inner metal foil conductor 4 to form the metal halide lamp having the inner volume less than 1c.c. Here the cross-section S at the electrode sealing section 2 is made within such range as 0.1XP<=S<=0.4XP+4 for the lamp power P while the ratio between the inner end section distance of the light emission tube M and the entire length L is limited in the range of 2.9X10<-1=M/L<=3.5X10<-1>. Consequently the heat transmission loss through the sealed section is reduced to suppress the excessive temperature rise, while the spectrum distribution is improved, the opaqueness of the silicon is prevented and the expiration of the oxidation of the metal foil conductor can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small metal housing with an internal volume of an arc tube of less than l@me.In recent years, there has been a demand for highly efficient light sources from the viewpoint of energy saving. Although metal halide lamps are used as light sources for indoor lighting, the use of metal halide lamps with high efficiency and high color rendering properties as light sources for indoor lighting is attracting attention. The conditions for using metal halide lungs as a light source for indoor lighting are the advantages of high efficiency, high color rendering properties, and long lifespan of S2 rings, as well as low wattage,
In particular, it can be used as a substitute for incandescent light bulbs and fluorescent lamps used in general households, and lamps with a power of 100 Watts or less, particularly 50 Watts or less, are required.

However, such metal halide lamps of 100 watts or less, or in some cases 50 watts or less, have the disadvantage that they cannot be miniaturized to the same degree as conventional medium/high-power lamps. In other words, within the conventional
High power, small size 2 of less than 100 watts and 1 ton of manufacturing technology
When applied to a light bulb, as the lamp power becomes smaller, the color rendering tends to be inferior to that of an incandescent lamp or a fluorescent lamp. This is because when the rung is made smaller, the heat conduction loss at the electrode sealing part increases proportionately, and the temperature rise in the coldest part becomes low, so the encapsulated metal is not evaporated sufficiently, and the encapsulated metal does not emit sufficient light. It's because you can't get it.

If the conventional medium/high wattage type rung ring sealing part is crushed into a flattened shape, and such a crushed sealing shape is applied to the small rung, the volume of the sealing part will be smaller than the discharge space. Since the relatively large size increases the heat conduction loss through the sealing portion, it is thought that this inhibits the rise in the temperature of the coldest part as described above.

Therefore, the inventors of the present invention tried to reduce the size of the sealing part in order to reduce the heat conduction loss in the sealing part, and this caused the temperature of the coldest part to rise, the luminescence of the encapsulated metal to increase, and the color rendering properties to decrease. I'm sure it will improve. However, as the size of the sealing part is further reduced, the average color rendering index (R1) reaches a saturated state, and despite this, the thermal load on the arc tube increases and the quartz constituting the arc tube is lost. It is clear that the transparent material may cause oxidation of the molybdenum foil in the sealing part.

Therefore, it has been found that the dimensions of the sealing portion have optimal upper and lower limits, and must be regulated within a range of 1 ilIO below these upper limits.

The present invention was made based on the above circumstances, and its purpose is to regulate the size of the electrode sealing part O,
The objective is to provide a small metal halide rande that can provide color rendering properties comparable to those of incandescent lamps and fluorescent lamps, and that does not cause devitrification of quartz or oxidation breakage of molybdenum foil.

The present invention will be explained below based on a few illustrated embodiments.

Figure 1 shows the structure of an arc tube with an internal volume of 1 a, c or less,
1 is a central spherical part made by expanding and molding quartz glass, and the letter board is formed into a spherical shape. An electrode sealing portion 2.2 is formed in the central spherical portion l, and an electrode J e J is sealed to these sealing portions 2.2.

An electrode coil is formed on the electrode axis 3°xa, and is connected to a metal foil conductor, such as a molybdenum foil 4.4, within the sealing portions 2,2. Note that the molybdenum foil 4.4 is connected to the external lead wire 5.5.

The central spherical part 1 and the sealing parts 2, 2 are made of eleven silica glass tubes, and the central spherical part 1 is formed by the above-mentioned through-hole expansion, and the sealing parts 2, 2 The molybdenum foil 4.4 is crushed or vacuum-sealed to form a bar shape with a substantially circular or elliptical cross section.

In addition, molybdenum foil 4.4 is for each watt! /c2n! A foil with a thickness suitable for the current, and a foil with a width that can tolerate the rung current, is used, and the thickness of the quartz wire is set so that the internal pressure of the arc tube during lighting of this type of rung is Since the pressure reaches 20 atmospheres or more, one with a length of 1 m or more is used.

Further, in the central spherical portion 1, predetermined amounts of water, scandium iodide, and 9 umium iodide are filled, and argon gas is filled at a predetermined pressure.

However, in the arc tube with such a configuration, the cross-sectional area of the sealing portion 2°2 at the location corresponding to the molybdenum foil 4.4 is 8 (
am2), Lang power is P (watts), total length of arc tube is L
(am), the distance between the inner ends of the central spherical part 1 is M (m)
If 0, IXP≦8≦0.4XP+4 - (1)!
, 9 X 10-'≦M/l, ≦3.5X10'''''
-(2) K is restricted.

These formulas (1) and (2) are 4hO obtained based on the inventor's experiments.

Let me explain about tzu(1)2. Although it is advantageous for the cross-sectional area S of the sealing part 2 to be small in order to reduce heat conduction loss, the sealing part 2 cannot be determined solely from the viewpoint of heat conduction loss, and the molybdenum foil 4, 4. Sealing performance must also be taken into consideration.

The size of the molybdenum foils 4, 4 differs depending on the rung power because the allowable value of the rung current differs for each watt.

In other words, if the cross-sectional area of the molybdenum foils 4.4 is selected to be large enough to allow a nine-ring current according to at least its rung power, the cross-sectional area of the molybdenum foils 4. The minimum cross-sectional area S of the sealing part 2°2 can be selected. From this point of view, the cross-sectional area S of the sealing part 2.2
When examining the relationship between P and lamp voltage P (watts), the results shown in FIG. 2 were obtained. In Figure 2, characteristic A is S-
0.1xp and characteristic B is S -0.4X
#give it to P + 4. And the cross-sectional area S is characteristic A and 3
It is sufficient if it is in the area surrounded by (shaded area), and therefore, 0, IXP≦S≦0.4XP+4.

If 8 is less than characteristic A, the quartz glass wall around each Lipden foil is too thin, causing the molybdenum foil to oxidize and break, and if S exceeds characteristic B, Since the thickness of the quartz glass is too large compared to the molybdenum foil, the quartz glass does not fit well with the quartz glass, and the adhesion between the two cannot be maintained well, causing leaks.

In this way, the cross-sectional area of the sealing part is restricted from being made small due to the sealing function of the molybdenum foil. 1) Based on the formula, we investigated how the sealing part should be selected in order to reduce the loss due to thermal conduction.

A metal halide lamp with a rating of 40 W (To#), 4 electrode distances, and a central spherical part 1 with an inner diameter of approximately 7 mm (inner volume approximately 0.2
c, e) mercury 6 “f/ iodide
, aq, sodium iodide 15M9. Argon gas was sealed at 200 Torr.

For the above 40W metal halide 2 pump, from Figure 2 and equation (1), the cross-sectional area 8 of the sealing part 2 is B=4■2~20
-2 range. Therefore, 8 w 4 m”
When we investigated the average color rendering index (R1) by changing 41 variously for each of 7■2#20 was2, we obtained the characteristics shown in Fig. 3. In the characteristics of Figure 3, 41
is less than 2.9 x 10-', and the heat conduction loss from the sealing part increases, causing the temperature of the coldest part to not rise sufficiently, causing scandium to emit light with a large number of line spectra in the visible range. Since it is small, the average color rendering index (R1) is 70 or less, and the color rendering property is lower than that of an incandescent lamp or fluorescent lamp fK. When M/L exceeds 2.9 x 10'', the light emission of scandium increases as the temperature of the coldest part increases,
Furthermore, sodium emission also begins to cause self-absorption, and R
1 rises. M/L is approximately 3.2 x 10”-
' At @ degree, R1 is suitable for saturated state, and even if M/L is increased thereafter, R1 shows saturated state, and VL is 3.5 x 1
Even if it exceeds 0-', there is no change in the saturation tendency.

However, if the MAL exceeds 3.5X10, the quartz in the arc tube will devitrify after being lit for 500 hours.
In addition, some pieces of molybdenum foil were found to have broken oxidized foil. l) It has been found that when M/L exceeds 3.5 x 10-', the thermal load on the arc tube is too large, resulting in a shortened life span.

Therefore, M/L of 2.0.
Must be within the range of 9X10"' or more, and M/L is 3.5X
If it exceeds 10", the life characteristics are poor, and M/L is 2.9
It can be seen that it must be restricted to a range of 8 from X10'' to 3.5X10-'.

Figure 4 shows the spectral distribution characteristics, and the solid line is at the S depth of 7.2 in a 40W metal halide 2 amplifier.
/L=2.9X10% The broken line is M/L -3,8X
10"" each shows the spectral distribution state.

As you can see from this diagram,? , M/L=3.3X10 (broken line), a large number of scandium emissions are observed in the visible range, and the spectrum F is observed to be diffused due to self-absorption of sodium. From this, Fig. 83 This confirms the tendency of the characteristics.

In addition, Fig. 5 shows M in a 20W metal hydride lamp.
The relationship between /L and average color rendering index R1 is shown, and the rung of 20W is as shown in FIG. 2 and equation (1), and l is in the range of 2 to 12. Therefore S −1! -O case and 8-12
The O color rendering properties were investigated for pigeon lofts with different M/I in the case of Section 2.
If L is in the range of 21X10 to a, 5xio'', then
It can be seen that this is a region where luminous efficiency is improved.

Therefore, within the range of formula (1), if it is regulated to 2.9X10''≦M/1.≦3.5X10-', improvement in color rendering properties and life characteristics can be observed.

This shows that the volume of the sealing part is regulated by equation (1) and equation Q), which is nothing but suppressing heat conduction loss through the sealing part and conversely preventing excessive increase. .

According to the present invention as described in detail above, the volume of the sealing portion is regulated and heat conduction loss is prevented, thereby improving color rendering properties and reducing the thermal load on the arc tube to increase its longevity. It has the advantage of preventing devitrification and breakage of metal foil after lighting for a certain period of time.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a side view of an arc tube, and FIGS. 2 to 5 are characteristic diagrams showing experimental results. DESCRIPTION OF SYMBOLS 1...Central spherical part, 2... Sealing part, 3-electrode, 4-
...Molybdenum foil.

Claims (1)

[Claims] In a metal halide lung whose internal volume of the arc tube is less than 1 e, e, the cross-sectional area 8 (■) of the metal foil conductor portion in the electrode sealing part is 0, IXP≦8≦0, 4XP+4, and the ratio of the arc tube inner end distance M to the arc tube total length M/
A small metal halide fan characterized by L being 2.9 x 10"'≦M/L≦3.5X10-'!