JP2006294441A - Discharge lamp device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp device in which temperature difference between the upper part and the lower part of a light emitting tube can be decreased with providing high optical output and no devitrification of the light emitting tube without a special cooling structure. <P>SOLUTION: The discharge lamp device of this invention comprises a discharge lamp 1 of which light emitting tube 10 has sealing parts 11 and 12 having a pair of electrodes 13 and 14 and embedded metal foil 15 formed in it, a reflecting mirror 2 around the discharge lamp 1, and a front glass 3 formed in front of an opening of the reflecting mirror 2. The front glass 3 is arranged so that the second focus 2 of the reflecting mirror 2 is folded back at the front glass 3 to the area where the metal foil 15, which is embedded in the sealing part 12 laid toward the front opening of the reflecting mirror, is placed. A wide sealed face 15a of the metal foil 15 embedded in the sealing part 12 is arranged in the vertical direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a discharge lamp device used for a light source of a projector.

  Conventionally, discharge lamp devices used as light sources for projectors use short arc type ultra-high pressure mercury lamps and metal halide lamps with high brightness and excellent color rendering, and the light emitted from these lamps is collected by a reflector. And used it.

An example of a conventional discharge lamp device is shown in FIG.
The discharge lamp 1 has an arc tube 10 and sealing portions 11 and 12 formed on both sides thereof. In the reflecting mirror 2, the reflecting surface 21 is a spheroidal surface, and the sealing portion 11 is fixed to the top opening 22 by the adhesive 4 in a state where one sealing portion 11 is inserted into the top opening 22 of the reflecting mirror 2. The other sealing portion 12 extends toward the front opening of the reflecting mirror 2, and a power supply line 17 is connected to the external lead bar 16 protruding from the sealing portion 12, so that the discharge lamp 1 and the reflecting mirror 2 are integrated. Are combined.
A front glass 3 is disposed in front of the front opening of the reflecting mirror 2.
Such a discharge lamp device is horizontally lit so that the electrode axis of the discharge lamp is horizontal.

The front glass 3 is disposed away from the front opening of the reflecting mirror 2 as shown in FIG. 4, and there is an obstacle in the light traveling direction between the front opening of the reflecting mirror 2 indicated by a dotted line and the front glass 3 for convenience. The hollow cylindrical intermediate member 5 is arranged so as not to become.
The intermediate member 5 may be a part of a casing that constitutes the discharge lamp device, or may be a holding member that holds the front glass 3.
Alternatively, the front glass 3 may be formed in close contact with the edge of the front opening of the reflecting mirror 5 without using the intermediate member 5.

  Since such a lamp device is required to be compact, a single-tube type discharge lamp without an outer tube is used as the discharge lamp. Recently, a discharge lamp has been developed that achieves higher light output and uses only mercury as the metal enclosed in the arc tube to increase the color rendering, and the internal pressure of the arc tube exceeds 100 atm. If such a discharge lamp breaks during lighting, there is a risk that fragments having high temperature and high energy will be scattered around.

In order to avoid such a problem, as shown in FIG. 4, the front opening of the reflecting mirror 2 is closed with the front glass 3 and the intermediate member 5 so as to prevent scattering of the fragments when the discharge lamp 1 is broken. Yes.
And the light radiated | emitted from the discharge lamp 1 is reflected by the reflective surface 21, passes the front glass 3, is condensed on the 2nd focus outside a discharge lamp apparatus, and displays on liquid crystal etc. display apparatuses via an optical system. Irradiated.

JP 2003-168303 A

  However, in such a discharge lamp device, since the discharge lamp 1 is horizontally lit, the temperature is different between the upper A point and the lower B point of the arc tube 10, and the upper A point is significantly higher than the lower B point. The lower point B is the coldest point of the arc tube 10.

In recent years, there has been a demand for increasing the light output emitted from the discharge lamp device, increasing the electric power input to the discharge lamp, raising the temperature of the coldest spot, enclosing a larger amount of mercury than before, all of the enclosed mercury Attempts have been made to evaporate and increase the light output.
However, although the temperature at the lower point B, which is the coldest point, rises, the temperature at the upper point A also rises, exceeds the melting temperature of the arc tube 10, and there is a problem that the arc tube 10 is broken.
In order to avoid such a problem, it is conceivable to add a structure that actively cools only the upper point A of the arc tube 10 in the reflecting mirror 2, but there is a problem that the cooling structure becomes complicated.

  In addition, since the temperature in the vicinity of the lower point B which is the coldest point of the arc tube 10 is low, the halogen cycle of the halogen gas sealed in the arc tube 10 becomes unstable, and this portion is devitrified. there were.

  The present invention has been made to solve such a problem, and without using a special cooling structure, the temperature difference between the upper part and the lower part of the arc tube of the discharge lamp can be reduced, and high light output can be achieved. It is another object of the present invention to provide a discharge lamp device in which the arc tube of the discharge lamp is not devitrified.

  The discharge lamp device according to claim 1 is configured to surround the discharge lamp with a discharge lamp in which a pair of electrodes are disposed in the arc tube and a sealing portion in which metal foil is embedded on both sides of the arc tube is formed. A reflecting mirror having a spheroidal surface as a reflecting surface is arranged, and one sealing portion of the discharge lamp is inserted into and fixed to the top opening of the reflecting mirror, and toward the front opening of the reflecting mirror. The other sealing portion extends, a power supply line is connected to the external lead rod protruding from the other sealing portion, a front glass is formed in front of the opening of the reflecting mirror, and the discharge is formed in the reflecting mirror. In the discharge lamp device containing the lamp, the front glass is arranged so as to be positioned in a region where the metal foil embedded in the sealing portion is present.

  The discharge lamp device according to claim 2 is the discharge lamp device according to claim 1, in particular, the electrode axis of the discharge lamp is horizontal, and the metal foil embedded in the sealing portion is The wide sealing surface to be sealed is positioned in the vertical direction.

  According to the discharge lamp device of the present invention, the temperature difference between the upper part and the lower part of the arc tube of the discharge lamp can be reduced without using a special cooling structure, and a high light output can be obtained. The arc tube is not devitrified.

FIG. 1 is an explanatory view of a discharge lamp device of the present invention.
The discharge lamp 1 has a quartz glass arc tube 10 and sealing portions 11 and 12 formed on both sides thereof. A pair of electrodes 13 and 14 made of tungsten are provided in the arc tube 10, and the distance between the electrodes is set to, for example, 1.2 mm so as to be close to a point light source. The arc tube 10 is filled with argon gas as a starting gas together with a predetermined amount of mercury. A metal foil 15 made of molybdenum connected to the electrodes 13 and 14 is hermetically sealed to the sealing portions 11 and 12. One end of an external lead rod 16 is connected to the metal foil 15, and the other end of the external lead rod 16 protrudes outside the sealing portions 11 and 12.

  The external lead rod 16 projecting from the sealing portion 12 extending toward the front opening of the reflecting mirror 2 is provided with a copper feeding line 17 having a nickel ring member formed at the tip thereof, and the ring member serving as the external lead rod 16. The feeder line 17 is connected to the external lead rod 16 by caulking.

The glass reflecting mirror 2 is formed so as to surround the discharge lamp 1, the reflecting surface 21 is a spheroidal surface, and one sealing portion 11 of the discharge lamp 1 is inserted into the top opening 22. In the state, it is fixed by the adhesive 4. As a result, the discharge lamp 1 and the reflecting mirror 2 are combined together.
A front glass 3 is disposed in front of the front opening of the reflecting mirror 2, and a hollow cylindrical shape is provided between the front opening of the reflecting mirror 2 indicated by a dotted line and the front glass 3 for convenience so as not to obstruct the light traveling direction. An intermediate member 5 is arranged.
The intermediate member 5 may be a part of a casing that constitutes the discharge lamp device, or may be a holding member that holds the front glass 3.
Alternatively, the front glass 3 may be formed in close contact with the edge of the front opening of the reflecting mirror 5 without using the intermediate member 5.
As a result, the discharge lamp 1 is accommodated in the reflecting mirror 2.

  The reflecting mirror 2 has a first focal point and a second focal point because the reflecting surface 21 is a spheroidal surface, and an arc generated between the electrodes 13 and 14 is positioned at the first focal point. A discharge lamp 1 is disposed, and an optical system (not shown) such as a lens is positioned at the second focal point.

The arc tube 10 is filled with 0.15 mg / mm ³ or more of mercury, halogen gas is also enclosed for the purpose of preventing devitrification of the arc tube 10, and the mercury vapor pressure at the time of lighting is 100 atm. That's what you get. This is intended to further increase the light output and improve the color rendering properties by increasing the mercury vapor pressure at the time of lighting, thereby suppressing the spread of the arc, so-called narrowing of the arc.

  If such a discharge lamp 1 breaks during lighting, there is a risk that fragments having high temperature and high energy will be scattered around. Therefore, the front glass 3 and the intermediate member 5 are arranged so as to close the front opening of the reflecting mirror 2. Thus, the discharge lamp 1 is accommodated in the reflecting mirror 5.

The front glass 3 is flat and exists between the first focal point and the second focal point of the reflecting mirror 2, and is arranged in a direction perpendicular to the optical axis X of the reflecting mirror 2. .
And about 97% of the light irradiated to the front glass 3 is transmitted through the front glass, and about 3% is reflected by the front glass 3 and returned.
This reflected light causes various phenomena depending on where it is returned to.

Next, an experiment was conducted to examine the relationship between the light returning from the front glass and the discharge lamp by changing the position of the front glass.
In this experiment, the temperature at the upper point A and the lower point B of the arc tube 10 shown in FIG. 1 was examined, and defects occurring in the discharge lamp itself were examined.
The position of the front glass is defined by the position where the position of the second focal point folded back by the front glass is located with respect to the discharge lamp.

  FIG. 2 schematically shows the position of the second focal point that is folded back by the front glass. Table 1 shows the position of the front glass, the description that defines the position, and the second focal point that is folded by the front glass shown in FIG. The positions of the two focal points are arranged and shown.

  Next, Table 2 shows the results of arranging the defects in the front glass positions 1 to 6, the arc temperature of the discharge lamp, and the discharge lamp itself.

As understood from Tables 1 and 2, at the front glass position 1, the light reflected and returned from the front glass is not efficiently irradiated to the arc tube, and the temperatures at the upper A point and the lower B point of the arc tube. The difference was large, the halogen cycle in the arc tube did not function normally, and there was a problem that the vicinity of the coldest point at the lower B point was devitrified after lighting for 1000 hours.
Furthermore, at this front glass position 1, if the amount of enclosed mercury is increased in order to obtain light output, the input power is increased and the temperature at the lower B point is raised, the vicinity of the upper A point of the arc tube is melted and the discharge lamp is damaged. Is.

  As understood from Tables 1 and 2, at the front glass position 2, there was a problem that the light reflected and returned from the front glass was applied to the external lead rod and the external lead rod was melted.

As understood from Tables 1 and 2, at the front glass positions 3 to 5, the light reflected and returned from the front glass is irradiated to the region where the metal foil of the sealing portion is present.
The light returned to this position is transmitted through the sealing portion and travels into the arc tube. The mercury in the arc tube is positively heated, and the arc tube is uniformly heated by the heated mercury. The temperature difference between the upper A point and the lower B point of the arc tube can be made 80 ° C. or less.
As a result, the halogen cycle in the arc tube functions normally, and the arc tube does not devitrify even after lighting for 1000 hours.
Further, when the front glass is arranged at the positions of the front glass positions 3 to 5, even if the amount of enclosed mercury is increased in order to obtain a high light output, the input power is increased and the temperature of the lower B point is increased, the arc tube The temperature does not reach until the upper point A of the glass melts, and the discharge lamp is not damaged.

As understood from Tables 1 and 2, at the front glass position 6, the light reflected and returned from the front glass is not efficiently applied to the arc tube, and the temperatures at the upper point A and the lower point B of the arc tube The difference was large, the halogen cycle in the arc tube did not function normally, and there was a problem that the vicinity of the coldest point at the lower B point was devitrified after lighting for 1000 hours.
Furthermore, at this front glass position 6, if the amount of enclosed mercury is increased to increase the input power and the temperature at the lower point B is raised in order to obtain light output, the vicinity of the upper point A of the arc tube is melted and the discharge lamp is damaged. Is.

  That is, by reflecting the front glass so that the second focal point folded back by the front glass is located in the region 3 in FIG. 2 where the metal foil embedded in the sealing portion exists. The mercury in the arc tube can be reliably heated by the emitted light, the temperature difference between the top and bottom of the arc tube can be reduced, devitrification of the arc tube can be prevented, and the coldest spot of the arc tube Even if the temperature is raised, the upper temperature of the arc tube has a sufficient allowable range up to the temperature at which the arc tube melts, and the arc tube does not melt and break.

FIG. 3 is a cross-sectional view of the sealing portion extending in the front opening direction of the reflecting mirror of the discharge lamp of the discharge lamp device of the present invention.
As shown in FIG. 3, in the metal foil 15 embedded in the sealing portion 12, the wide sealing surface 15a to be sealed is perpendicular to the electrode axis of the discharge lamp which is the vertical direction on the paper surface. Are arranged as follows.

  As a result, of the light reflected by the front crow, the light transmitted through the sealing portion 12 in which the metal foil 15 is embedded from the upper side to the lower side is not blocked by the metal foil 15, The efficiency of light that can reach the arc tube and heat mercury in the arc tube is improved.

It is explanatory drawing of the discharge lamp apparatus of this invention. It is explanatory drawing which shows typically the position of the 2nd focus | fold by the front glass in the discharge lamp apparatus of this invention. It is sectional drawing of the sealing part extended in the front opening direction of the reflective mirror of the discharge lamp of the discharge lamp apparatus of this invention. It is explanatory drawing of the conventional discharge lamp apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge lamp 10 Arc tube 11 Sealing part 12 Sealing part 13 Electrode 14 Electrode 15 Metal foil 16 External lead rod 17 Feed line 2 Reflecting mirror 21 Reflecting surface 22 Top opening 3 Front glass 4 Adhesive 5 Intermediate member

Claims (2)

A discharge lamp in which a pair of electrodes are arranged in the arc tube and a sealing portion in which metal foil is embedded on both sides of the arc tube is formed, and a reflecting mirror having a spheroidal surface that surrounds the discharge lamp. Arranged, and one sealing portion of the discharge lamp is inserted and fixed to the top opening of the reflecting mirror, and the other sealing portion of the discharge lamp extends toward the front opening of the reflecting mirror, In the discharge lamp device in which the power supply line is connected to the external lead rod protruding from the other sealing portion, the front glass is formed in front of the opening of the reflecting mirror, and the discharge lamp is accommodated in the reflecting mirror.
The front glass is disposed such that the second focal point of the reflecting mirror is folded back by the front glass and is located in a region where the metal foil embedded in the sealing portion is present. Lamp device. The electrode axis of the discharge lamp is horizontal,
The discharge lamp device according to claim 1, wherein the metal foil embedded in the sealing portion has a wide sealing surface to be sealed positioned in a vertical direction.

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