JP4199656B2 - Metal vapor discharge lamp and lighting device - Google Patents

Description

  The present invention relates to a metal vapor discharge lamp and a lighting device including the metal vapor discharge lamp.

A metal vapor discharge lamp, for example, a metal halide lamp, is generally configured by housing an arc tube in an outer tube and sealing the end of the outer tube with a stem (for example, Patent Document 1).
In recent years, metal halide lamps have been in demand as indoor lighting in stores and the like because of their good color rendering properties, so that they can be installed even in narrow spaces, and the total length and outer diameter of the metal halide lamp (hereinafter referred to as “lamp size”). There is a strong demand for miniaturization as much as possible.
JP-A-11-96973

  Therefore, the present inventors manufactured a metal halide lamp having a lamp size further reduced than before and conducted a life test in order to meet the above-mentioned demand for downsizing. As a result, it was found that cracks may occur in the stem within a short time of 1000 hours. This is because the distance between the center of the arc tube and the stem has become closer with the shortening of the overall length of the metal halide lamp, and the temperature change between when the metal halide lamp is turned on and when the lamp is turned off increases, resulting in the heat acting on the stem. This is thought to be due to the increased stress.

It has also been found that the temperature of the outer tube may become abnormally high as the outer diameter of the outer tube is reduced. When the temperature of the outer tube becomes high as described above, there is a possibility that the outer tube may be deformed.
In the outer tube, an inert gas may be sealed at a low pressure in order to prevent discharge from occurring between the power supply lines for supplying power to the arc tube in the outer tube. If cracks occur in the outer tube or the outer tube is deformed, the outside air enters the outer tube, which causes the metal members constituting the mount to oxidize and become brittle. In the worst case, the metal halide lamp will not light properly, resulting in a short life. Sometimes.

Such a problem can occur not only in metal halide lamps but also in general in miniaturization of metal vapor discharge lamps in which an arc tube is housed in an outer tube.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a metal vapor discharge lamp that has a smaller lamp size than conventional ones and that is less prone to stem cracks and outer tube deformation.

In order to achieve the above object, a metal vapor discharge lamp according to the present invention includes an outer tube having one end sealed with a stem, an arc tube housed in the outer tube and having a light emitting unit , A metal vapor discharge lamp having a rated power of 70 W, and having a sleeve surrounding the arc tube, from the end of the outer tube opposite to the side where the stem is sealed, When the distance to the arc tube side end is L1, the distance from the center of the light emitting unit to the arc tube side end of the stem is L2, and the outer diameter of the outer tube is D, 55 mm ≦ Each condition of L1 ≦ 80 mm, L2 ≧ 30 mm, 1.83 ≦ L1 / D ≦ 2.75 is satisfied simultaneously.

  Moreover, the illuminating device which concerns on this invention was equipped with the said metal vapor discharge lamp as a light source, It is characterized by the above-mentioned.

  According to the metal vapor discharge lamp of the present invention, the distance from the end of the outer tube on the side opposite to the stem to the end of the stem on the arc tube side, the end of the outer tube on the side opposite to the stem to the arc tube of the stem By setting the distance to the end on the side and each value of the outer diameter of the outer tube so as to satisfy predetermined conditions, the cracks of the stem and the deformation of the outer tube are prevented as much as possible. The lamp size can be reduced.

Hereinafter, embodiments in which the present invention is applied to a metal halide lamp will be described with reference to the drawings.
FIG. 1 is a front view of a metal halide lamp (hereinafter simply referred to as “lamp”) 100 according to the present embodiment. In the figure, the outer tube 2 and the sleeve 8 are shown in cross section so that the internal structure can be easily understood.

As shown in the figure, the lamp (rated power 70 W) 100 includes a substantially cylindrical outer tube 2 made of hard glass, for example, and an arc tube 4 housed in the outer tube 2.
One end portion of the outer tube 2 is sealed by a stem 5, and a base 6 is attached so as to cover the sealing portion. The other end of the outer tube 2, that is, the end opposite to the stem 5 has a hemispherical blocking portion 2 a. The stem 5 is made of hard glass, for example.

  The arc tube 4 has an envelope made of, for example, alumina ceramic, and includes a light emitting portion 4a that forms a discharge space therein, and thin tube portions 4b and 4c provided at both ends of the light emitting portion 4a. Yes. A predetermined amount of start-up rare gas such as argon gas, light-emitting substance such as metal halide, and mercury are sealed in the light-emitting portion 4a. In addition, the point shown with the code | symbol C in the light emission part 4a is a point which shows the light emission center of the said light emission part 4a. More specifically, the light emission center corresponds to an intermediate position between the distances between the electrodes of a pair of electrodes (not shown) disposed to face each other in the light emitting portion 4a.

Further, a power supply body (not shown) made of, for example, conductive cermet is inserted into the thin tube sections 4b and 4c, and between the thin tube sections 4b and 4c and the power supply body at the end opposite to the light emitting section 4a. It is sealed with a sealing material such as frit glass poured into the gap.
In order to prevent the outer tube 2 from being damaged when the arc tube 4 is damaged, for example, nitrogen gas is sealed in the outer tube 2 as an inert gas, for example, at a normal temperature of about 44 kPa to 49 kPa. A sleeve 8 is provided so as to surround the arc tube 4.

  The sleeve 8 is made of, for example, quartz glass and has a cylindrical shape with both ends opened, and the arc tube is provided via a support 10 or a metal plate 12 disposed so as to sandwich the sleeve 8 from above and below. 4 is held at a position surrounding 4. In the present embodiment, the open end of the sleeve 8 is almost entirely closed by the support 10 and the metal plate 12. However, the present invention is not limited to this. For example, about half or most of the open end may be opened. Various supports and metal plates may be used.

  The power supply lines 14 a and 14 b are supported by the stem 5, and one end portion of the power supply lines 14 a and 14 b extends from the stem 5 to the inside of the outer tube 2 and is led out from both ends of the thin tube portions 4 b and 4 c of the arc tube 4. It is joined to the external lead wires 7a and 7b made of niobium so that power is supplied to a pair of electrodes (not shown) in the light emitting portion 4a and the light emitting tube 4 is held at a predetermined position in the outer tube 2. It has become.

Note that the member denoted by reference numeral 16 is a known getter for adsorbing impurities in the outer tube 2.
Here, in the lamp 100, as shown in FIG. 1, the distance from the end of the closed portion 2a of the outer tube 2 to the end of the stem 5 on the arc tube 4 side is L1, and the emission center (point C) of the light emitting unit 4a. ) To the end of the stem 5 on the arc tube 4 side is L2, the maximum outer diameter of the outer tube 2 is D, and the optimum range of each dimension is defined by the following three tests.
(Test 1)
In the lamp 100 having the same configuration as that of FIG. 1, ten lamps having a D size of 30 mm, a constant L2 of 30 mm, and a change of L1 from 50 mm to 90 mm are manufactured, and a life test (lighting time) is performed. A continuous repetitive test of lighting for 5.5 hours and turning off for 0.5 hours) was performed until 9000 hours, and it was examined whether or not the stem 5 was cracked.

The test (hereinafter. Referred to as "Test 1") The specific specifications of the amount of luminescent material sealed in the discharge space, the DyI ₃ 0.5 mg, the HoI ₃ 0.5 mg, the TmI ₃ 0 A lamp 100 containing 2.8 mg in total of 0.5 mg, 0.7 mg of NaI, and 0.6 mg of TlI and 0.6 mg of TlI and containing 20 kPa of argon as a rare gas for assisting startup was used. Further, the light emitting portion 4a of the arc tube 4 has a length of 12 mm, a maximum outer diameter of 9.9 mm, and the thin tube portions 4b and 4c have a length of 10 mm and an outer diameter of 2.6 mm. The thin tube portions 4b and 4c are opposite to the discharge space. The length of the glass frit poured from the end of the glass was 4.5 mm.

  The results of Test 1 are shown in Table 1 below.

同表に示すように、Ｌ１＝５０ｍｍの場合は、１０本中２本のランプ１００のステム５にクラックが発生しているため、「×」と判定した。
また、Ｌ１＝９０ｍｍの場合は、ステム５にクラックが発生していないものの、ランプサイズの小型化という観点からは、Ｌ１≦８０ｍｍであることが好ましいので、「△」と判定した。

As shown in the table, when L1 = 50 mm, cracks occurred in the stems 5 of two of the ten lamps 100, and therefore, “x” was determined.
Further, when L1 = 90 mm, although cracks did not occur in the stem 5, it was determined that “L1 ≦ 80 mm” from the viewpoint of reducing the lamp size.

The lamp 100 that can be reduced in size (L1 ≦ 80 mm) and that does not crack in the stem 5 for a long time of 9000 hours was determined as “◯”.
From the results of Test 1, it can be said that the range of L1 is preferably 55 mm ≦ L1 ≦ 80 mm.

The upper limit of L1 is more preferably 70 mm or less from the viewpoint of further reducing the lamp size.
Further, in the above test 1, the specific results for the case where D is constant at 30 mm are shown, but it has been proved by experiments that cracks do not occur in the stem 5 even if the size of D is reduced to 20 mm. Has been.
(Test 2)
Next, in the preferable range of L1 (55 mm ≦ L1 ≦ 80 mm) obtained in the test 1, when L1 that can achieve the most miniaturization of the lamp 100 is constant at 55 mm, L2 is from 25 mm. Ten lamps 100 that were changed to 35 mm were manufactured, and a life test (hereinafter referred to as “test 2”) was performed in the same manner as in test 1 above, and whether or not cracks occurred in the stem 5 was examined. In Test 2, D was fixed at 30 mm, and the dimensions of the arc tube 4 and specific specifications of the luminescent material and rare gas sealed in the discharge space were the same as in Test 1.

  The results of Test 2 are shown in Table 2 below.

同表に示すように、Ｌ２＝２５ｍｍの場合は、１０本中２本のランプ１００のステム５にクラックが発生しているため、「×」と判定した。そして、Ｌ２＝３０ｍｍ，３５ｍｍの場合はステム５にクラックが発生しなかったので「○」と判定している。

As shown in the table, when L2 = 25 mm, cracks were generated in the stems 5 of the two lamps 100, and therefore, “x” was determined. When L2 = 30 mm and 35 mm, no crack was generated in the stem 5, so it was determined as “◯”.

In the case of L2 = 25 mm, the crack occurred in the stem 5 because the distance between the center (point C) of the light emitting portion 4a and the stem 5 is close as described above, and the stem 5 becomes high temperature and is generated inside. This is thought to be due to the increase in thermal stress.
From the results of Test 2, it can be said that the range of L2 is preferably L2 ≧ 30 mm.
In Test 2 above, the test is not performed for values where L2 is greater than 35 mm. This is because L1 is kept constant at 55 mm, and if L2 is larger than 35 mm, it becomes difficult to store the arc tube 4 in the outer tube 2. That is, the upper limit of the range of L2 is appropriately determined to a value that does not cause a problem in practice according to the size of the arc tube 4 housed in the outer tube 2.

Further, in the test 2, the test was performed for the case where L1 = 55 mm. However, if L1 is larger than 55 mm, the space in the outer tube 2 is increased accordingly. If it is ≧ 30 mm, it is considered that the probability of cracks occurring in the stem 5 can be kept low.
(Test 3)
From the tests 1 and 2, it was found that the lamp 100 having the smallest L1 = 55 mm and L2 = 30 mm has the smallest lamp size and no cracks in the stem 5 over a long period of time. Therefore, in the case where L1 is kept constant at 55 mm and L2 is kept constant at 30 mm, in order to investigate the optimum value of the outer diameter D, a lamp 100 in which D is changed from 15 mm to 45 mm is manufactured, and the outer tube temperature is measured. (Hereinafter referred to as “Test 3”). Here, the outer tube temperature is the temperature of the outer wall of the outer tube directly above the light emitting portion 4a when the lamp is lit horizontally at room temperature. When the lamp is lit horizontally, the arc tends to bend upward due to the convection of the vapor inside the arc tube 4, so that the temperature at the top of the light emitting portion 4a tends to be locally high in the arc tube 4. For this reason, in the outer tube 2, it is considered that the temperature directly above the light emitting portion 4a is the highest.

The dimensions of the arc tube 4 and the specific specifications of the luminescent material and rare gas sealed in the discharge space were the same as in Test 1.
The results of Test 3 are shown in Table 3 below.

同表に示すように、外管２の外径Ｄを小さくするに連れて、外管温度が高くなる結果となった。これは、発光部４ａと外管２とが近づいたためである。
また、同表においては、外管温度が、外管材料である硬質ガラスの歪点約４９０℃に近くなると、外管２が脆くなったり、変形が生じるおそれがあるため、当該外管温度が４２０℃以上となった場合を「×」と判定した。また、Ｄが３０ｍｍより大きい場合は、外管温度の点では問題がないものの、ランプサイズの小型化という観点から「△」と判定した。そして、これら以外のＤ＝２０ｍｍ，３０ｍｍの場合を「○」と判定した。

As shown in the table, the outer tube temperature increased as the outer diameter D of the outer tube 2 was reduced. This is because the light emitting unit 4a and the outer tube 2 are close to each other.
In the same table, when the outer tube temperature is close to the strain point of hard glass, which is the outer tube material, about 490 ° C., the outer tube 2 may become brittle or deform. When it became 420 degreeC or more, it determined with "x". On the other hand, when D was larger than 30 mm, although there was no problem in terms of the outer tube temperature, it was determined as “Δ” from the viewpoint of reducing the lamp size. And the case of D = 20mm and 30mm other than these was determined as "(circle)".

Here, paying attention to the relationship between D and L1, the value of L1 / D when determined as “◯” is L1 / D = 55/20 = 2.75 when D = 20 mm, and D = 30 mm. In this case, since L1 / D = 55/30 = 1.83, the range of L1 / D is preferably 1.83 ≦ L1 / D ≦ 2.75.
Test 3 shows the result when L1 is 55 mm. However, if the value of L1 is in the range of 55 mm ≦ L ≦ 80 mm, L1 / D is also preferably in the above range. .
(Other)
In each test of the present embodiment, the arc tube 4 having the same size is used. However, when L1 is larger than 55 mm, the light emission is performed in consideration of the optical center distance and the light distribution characteristics. The total length of the tube 4 may be increased.

(Lighting device)
If the lamp described in this embodiment is used as a light source of an illumination device, a more compact illumination device can be provided. FIG. 2 is a cross-sectional view showing a schematic configuration of an illumination device 200 using the lamp 100 having the configuration of FIG. The lamp 100 is shown with a part cut away so that the inside thereof can be seen.

As shown in the figure, the illuminating device 200 is, for example, for a downlight incorporated in a ceiling, and is composed of a device main body 210 embedded in the ceiling 250 and a lamp 100 attached to the device main body 210. The
The apparatus main body 210 includes a shade portion 212 that is spread downward, a socket portion 214 that is disposed in the shade portion 212 and that is detachably attached to the lamp portion 100, and the lamp 100 that is attached to the socket portion 214. A lighting circuit 220 for lighting, and is mounted so that the outer periphery of the cap portion 212 is in contact with a mounting hole 252 formed in the ceiling 250.

  The socket part 214 is attached to the base plate 216 that is attached to the upper end of the shade part 212 and extends in a direction parallel to the ceiling (right direction in the figure). The lighting circuit 220 is housed in a case 222 attached to a portion of the base plate 216 corresponding to the outside of the cap portion 212.

  The metal vapor discharge lamp according to the present invention has a small lamp size and is resistant to stem cracks and deformation of the outer tube, and can be used for a long time. Therefore, it can be used for metal vapor discharge lamps such as metal halide lamps. it can.

It is a front view of the metal halide lamp which concerns on embodiment. It is a figure which shows the illuminating device using the metal halide lamp of FIG.

Explanation of symbols

2 Outer tube 2a Blocking portion 4 Light emitting tube 4a Light emitting portion 4b, 4c Thin tube portion 5 Stem 8 Sleeve 100 Metal halide lamp 200 Illumination device

Claims (2)

An outer tube with one end sealed by a stem;
An arc tube housed in the outer tube and having a light emitting portion ;
A sleeve surrounding the arc tube;
A metal vapor discharge lamp having a rated power of 70 W ,
The distance from the end of the outer tube opposite to the side where the stem is sealed to the end of the stem on the arc tube side is L1,
The distance from the center of the light emitting unit to the end of the stem on the arc tube side is L2,
When the outer diameter of the outer tube is D,
55 mm ≦ L1 ≦ 80 mm,
L2 ≧ 30 mm,
1.83 ≦ L1 / D ≦ 2.75
A metal vapor discharge lamp characterized by simultaneously satisfying the above conditions. Lighting apparatus characterized by comprising a metal vapor discharge lamp according to claim 1 as a light source.

Images