JPS6070655A - Small-sized high pressure discharge lamp device - Google Patents

Abstract

PURPOSE:To unify a distribution of light by making the thickness of the vicinity of the central part of a luminous tube to be the maximum while continuously thinning the thickness in proportion as nearing the vicinity of the end part for incorporating it into a reflection mirror in order to form a small-sized high voltage discharge lamp device. CONSTITUTION:A small-sized short arc xenon discharge lamp A is combined with a reflection mirror 13 for constituting a small-sized high pressure discharge lamp device. Thereby, the luminous tube 1 made of quarz glass is made elliptical or spherical and the electrodes 2 and 3 of tungsten or the like are sealed to both ends for being formed by further sealing xenon inside while making the thickness ta near the center to be the maximum and the thickness tb near the end part to be the minimum not less than 1mm. in order to form so that the thickness may be continuously changed. Accordingly, the light from the luminous tube 1 is refracted toward the central part and discharged while being reflected by a reflection mirror 13, thus reducing uneven intensity of illumination on the irradiation face, while removing the shielding effect due to the luminous tube 1 and the sealing part 11.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a compact high-pressure discharge lamp device that is a complete combination of a compact high-pressure discharge lamp and a reflector.

Conventional configuration and its problems Small spotlights are used as a type of energy-saving lighting for show windows, precious metal products, etc.

Traditionally, incandescent light bulbs have been widely used as small spotlights, but in recent years, short-arc xenon discharge lamps, which provide high brightness and easy spot illumination, have been used for energy saving purposes.
Small high-pressure discharge lamps such as ultra-high-pressure mercury lamps and metal/Ride Langs have come into use. In order to fully utilize the effects of spot lighting with high brightness, there is a need to develop a compact high-pressure discharge lamp device in which the arc tube and reflector are as small as possible, and the illuminance is less uneven.

Incidentally, a large-sized high-pressure discharge lamp of 200 W or more has a structure in which the arc tube is entirely held within an outer bulb provided with an aluminum reflective film, and the outer bulb is completely filled with inert gas. These large reflective high-pressure discharge lamps have extremely high luminous flux values, so
It is installed and used in a high place relatively far away from the irradiated object.

On the other hand, in order to obtain high-intensity and efficient spot illumination with a small high-pressure discharge lamp, it is necessary to irradiate the object from a relatively close location. Therefore, in small-sized high-pressure discharge lamps, sufficient measures must be taken to deal with light distribution, particularly uneven illuminance on the irradiation surface, which has not been a problem in conventional large-sized reflective high-pressure discharge lamps.

In large reflective high-pressure discharge lamps with an outer tube, the arc tube is large, so the reflected light is blocked by the arc tube support, the arc tube itself, and especially the arc tube seal, resulting in uniform light distribution. However, by installing the device at a high place relatively far from the object to be irradiated, uneven illuminance can be alleviated, and by providing a diffusion film on the front surface of the outer tube, a uniform light distribution can be achieved.

However, in the case of the small high-pressure discharge lamp targeted by the present invention, the ratio of the sealed part to the light emitting part of the arc tube is large, so it is difficult to shield reflected light by the sealed part of the arc tube or the arc tube itself. If sufficient measures are not taken, a problem will occur in which illuminance becomes uneven on the irradiated surface.

Purpose of the Invention The present invention has been made in view of the above circumstances.
The present invention provides a compact high-pressure discharge lamp device in which uniform light distribution is possible without the reflected light from a reflecting mirror being blocked by an arc tube sealing part or the like, and in which unevenness in illuminance on an irradiation surface is reduced.

Structure of the Invention The present invention provides an arc tube whose entire shape is elliptical or spherical, where the wall thickness near the center of the arc tube is maximized, and the wall thickness is continuously thinned as it approaches the ends of the arc tube. 11mm1
1, and the lens action refracts the light in the direction of the larger wall thickness, increasing the emitted light at the center of the arc tube.
By effectively utilizing the reflected light from the reflecting mirror, uniform light distribution is achieved.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

Figure 1 shows a combination of a 65W small short arc xenon discharge lamp and a reflector.A discharge tube 1 made of quartz glass has electrodes 2 made of high melting point material such as tungsten at both ends.
．． 3 is sealed via a metal foil 4.6 made of molybdenum or the like,
A sealing part 6.7 is formed. Lead wires 8.9 are connected to the ends of these metal foils 4.6. Metal caps 10 and 11 are provided at both ends of the arc tube 1. About 16 atmospheres of xenon 12 is sealed inside the arc tube 1 to constitute a short arc xenon discharge lamp.

Such a small short arc xenon discharge lamp is fixed to a predetermined position of the reflector 13 with bolts 14 or cement to constitute a small short arc xenon discharge lamp device,
The light is turned on by applying a voltage to the lead wire 8.9. The opening portion of the arc tube 1 has an ellipsoidal or spherical shape in order to smoothly generate gas convection within the discharge space and provide pressure resistance. However, in order to prevent the metal foil 4.6 from oxidizing due to lighting in free air and the rise in temperature of the arc tube, it would impair airtightness and cause leaks.
Sealing part 6. The end time is relatively long.

FIG. 2 shows a cross-sectional view of such an arc tube, and the arc tube 1 is constructed so that the wall thickness distribution of the light emitting part is different. That is, the wall thickness t2L near the center of the arc tube 1 is maximized, the wall thickness tb near the end of the arc tube 1 is minimized, and the wall thickness changes continuously from the wall thickness ta to the wall thickness tb. ing. Since the arc tube has an elliptical or spherical shape, such thickness changes occur easily, and a lens-like thickness is formed.

The minimum wall thickness tb takes into account the type of noble gas and additives to be sealed, and the internal pressure depending on the wattage.

There must be. The compact high-pressure discharge lamp device according to the present invention aims to raise the temperature of the arc tube by lighting the arc tube entirely in free air, and to increase the pressure or vapor pressure of the enclosed material at the time of lighting. Compared to the general type that uses a tube, it is set up in a smaller size, and the internal pressure of the arc tube reaches 26 to 40 atmospheres or more. Considering the increase in lamp voltage, the deterioration of the pressure resistance of the tube wall, and ensuring safety when used in free air, the arc tube must have a pressure resistance of 60 atmospheres. Therefore, with a pressure resistance of 60 atm as the limit value, the minimum wall thickness tb
It was confirmed through experiments that a thickness of 1 mm or more is required.

By having such a wall thickness distribution, a lens-like wall thickness is formed, and the light is refracted in the direction of the larger wall thickness, thereby improving the light distribution to increase the emitted light at the center of the arc tube. can. The principle will be explained in detail using FIGS. 3(A) to 3(C). Figure 3 (A) shows the shape of the arc tube when it is spherical or spherical with no change in wall thickness, and Figure 3 (B) shows the same shape as the arc tube described above, but the thickness of the center part is thicker than the ends. When the thickness is small, Fig. 3 (0) relates to this example,
The cases in which the arc tube has an elliptic spherical shape or a spherical shape and are thicker at the center than at the ends are shown in each case. Figure 3 (A
) to (C), the entire inner surface of the arc tube - the diameter of the curvature,
The explanation will be given by considering a case in which light rays OA are emitted from the center of the arc tube in the same direction.

In the case of Fig. 3 (A), the light ray OA incident at the incident angle θ is once refracted within the quartz glass of the arc tube 120 at an angle smaller than the incident angle θ and becomes the light ray AB, and when it exits from point B, the light ray The light beam is refracted at an angle greater than the incident angle of AB and is emitted as a light beam Be. In other words, Fig. 3 (
In case A), the refracted light Be is slightly eccentric to the center of the extension line OAD line of the incident light in the OA force direction, but
The light beam is emitted at approximately the same angle as the incident angle θ of the incident light beam OA.

In the case of FIG. 3(B), the light ray OA incident at the same angle of incidence as in FIG. 3(A) is refracted within the quartz glass of the arc tube 13 at the same angle as in the case of FIG. 3(A). It becomes AB. The process up to the ray OAB is the same as in Figure 3 (A), but since the upper part of the diagram is shaped like a large double sword, the light emitted from point B goes in the direction of the thicker wall. Due to the lens effect of refraction, the light ray BC' is refracted upward at an angle greater than the incident angle of the light ray OA.
and is released. That is, it spreads to the end of the arc tube 13 and is emitted.

In the case of FIG. 3(C), that is, in the case of the embodiment of the present invention, the light ray OA incident at the same angle of incidence as in the cases of FIGS. Diagram (A)
.

It is refracted to the same angle as in case (B) and becomes light ray AB.

The light ray 0AB-i is the same as in Fig. 3 (A), @), but since the lower part shown in the figure is formed with a large thickness, the light going out from point B is Due to the lens effect of refraction in the direction of greater thickness, the light beam is refracted at an angle smaller than the incident angle of the light beam OA and is emitted downward as a light beam BC. , +1.

In the above explanation, we have focused on a single ray of light emitted from near the center of the arc tube, and have considered a 111-round sphere with an inner surface of the arc tube that approximates the actual example. Even if we consider the case where the inner surface of the tube is spherical, if the wall thickness near the center of the arc tube is thicker, ellipsoidal or spherical, the light will basically be concentrated toward the center of the arc tube due to the lens effect. is easily understood.

Next, in FIGS. 4(A) to (C), the emitted light and the reflected light are generated when an arc tube with an inner surface of an elliptical spherical shape and a different wall thickness distribution is incorporated into a reflecting mirror. Please explain all the conditions of the light. A case will be described in which the curved surface of the reflecting mirror 13 is parabolic, and the focal position of the reflecting mirror 13 and the discharge center point of the arc tube are made to coincide.

FIG. 4(A) shows the case where there is no change in the wall thickness of the arc tube.
Synchrotron radiation O emitted from the end of the arc tube toward the rear of the reflector
E becomes a light ray EE' and is reflected toward 011. However, in the case of a small high-pressure discharge lamp in which the ratio of the sealed part to the light emitting part of the arc tube is large, the light ray EE' is likely to be blocked by the sealed part, and there is a strong tendency for uneven illuminance to occur on the irradiated surface. Also,
Synchrotron radiation O emitted from the end of the arc tube toward the front of the reflector
In the case of a compact reflecting mirror, F is directly irradiated as light without being incident on the reflecting surface, causing uneven illuminance. Furthermore, the radiation angle and illuminance of the arc tube vary greatly depending on the position, which tends to cause variations in quality.

Figure 4 (B) shows the case where the thickness of the central part of the arc tube is smaller than that of the end, and the light is refracted and emitted from the arc tube toward the end, so it is emitted from the end of the arc tube to the rear of the reflector. The synchrotron radiation OE emitted in the direction is reflected by the bottom side of the reflecting mirror and becomes the light ray EE.
', and is reflected again at the front and becomes the ray E/E“
and is reflected forward. The light ray HE' is shielded by the arc tube and reflected again at the front surface to become the light ray E'K", making it difficult to design a reflecting mirror to obtain uniform light distribution. Since the synchrotron radiation OF emitted from the end of the arc tube toward the front of the reflector spreads to the end of the arc tube, in the case of a compact reflector, it is irradiated directly as light without entering the reflecting surface, and the fourth Diagram (A)
This causes more uneven illumination than in the case of . Furthermore, the radiation angle and illuminance vary greatly depending on the mounting position of the arc tube, and the variation in quality is larger than in the case of FIG. 4(A).

FIG. 4(C) shows the case of the embodiment of the present invention, that is, the case where the thickness of the central part of the arc tube is larger than that of the end parts. , since the synchrotron radiation OR and OF emitted from the end of the arc tube toward the rear and front of the reflector are refracted toward the center of the reflector in the case of Fig. 4 (A) and (B). There is little blocking of reflected light by the arc tube or sealing part, and even in the case of a compact reflecting mirror, there is little direct light that does not enter the reflecting surface, so uneven illuminance does not occur on the irradiated surface. Furthermore, since the light emitted from the arc tube is efficiently reflected by the reflecting mirror, the relative illuminance increases, resulting in a more uniform light distribution with fewer complicated reflections than in the cases shown in Figures 4 (A) and (B). It is easy to design a compact reflector.

Figure 6 shows the results of improving the light distribution characteristics of a small short arc xenon discharge lamp device manufactured based on the above principle. The manufactured compact short-arc xenon discharge lamp has a power consumption of 55 W, the arc tube is made of ellipsoidal spherical quartz glass with a maximum inner diameter of 8 mm, xenon at 16 atmospheres is sealed inside, and the arc tube sealing part has a diameter of 5 mm. It has a cylindrical shape with a diameter of 1 mm and the length of one side of the sealing part is 25 mm. Three types of arc tubes with different wall thickness distributions were fabricated. That is, (1) wall thickness ta
= tb 1.2mm arc tube with no change in wall thickness, (2
) The end part becomes thicker continuously with the wall thickness ta of the center part = 1 mm, and the end part becomes thicker with the end part wall thickness 1b ==: 2 mm, (3) The end part becomes continuously thicker with the wall thickness ta of the center part = 2 mm. becomes thinner, and the opening diameter of each arc tube with end wall thickness tb = 1 mm is 4.
FIG. 6 shows the light distribution characteristics directly below 1.6 m when the reflector is installed in a reflecting mirror with a parabolic curved surface of 0 mm and a bottom height of 45 mm. In the figure, the above (1), (2), (3
) The results for each case are represented by curves I, II, and Ml.

As is clear from FIG. 6, in the relative illuminance of the irradiated surface, curves I and II had uneven illuminance near the center, and the radiation angle d also had a wide and unclear pattern.

On the other hand, in curve (2), the relative illuminance of the irradiated surface was made uniform and the illuminance level increased by about 30%, and the radiation angle d also satisfied the design value, resulting in a clear pattern.

Similar results were also obtained when experiments were conducted using a small ultra-high-pressure mercury lamp whose arc tube was filled with mercury and argon, and a small metal halide lamp whose interior was filled with tin halide and mercury. Furthermore, ta/l
Similar results were obtained when experiments were carried out over a wide range of b from 1.6 to 3.0.

As described in detail, the present invention makes the shape of the light emitting part of the arc tube ellipsoidal or spherical, maximizes the wall thickness near the center of the arc tube, and decreases the wall thickness as it approaches the ends of the arc tube. By continuously thinning the wall to a minimum of 1 mm and using lens action to refract the light in the direction of the thicker wall, increasing the amount of light emitted from the center of the arc tube, the reflected light can be effectively used with a compact reflector. It is possible to provide a compact high-pressure discharge lamp device that can be used to achieve uniform light distribution, illuminance level, and clear pattern.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view of a small high-pressure discharge lamp device that is an embodiment of the present invention, and FIG. 2 is a partial sectional view of the small 7-dose lamp.
Figures 3 (A) to C) are diagrams for explaining the lens effect of the compact high-pressure discharge lamp according to the present invention in comparison with other lamps, and Figures 4 (A) to C) are wall thickness distributions. FIG. 6 is a diagram illustrating the light distribution characteristics of various small high-pressure discharge lamps. 1... Arc tube, 2.3... Electrode, 6,
7...Sealing part, 8.9...Lead wire,
10.11...cap, 13...reflector. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3 Figure 4 Figure 4 Figure 65 Angle of elbow

Claims (1)

[Claims] In a compact high-pressure discharge lamp device comprising a light-emitting tube made of glass with electrodes at both ends and a light-emitting portion having an elliptical or spherical shape, the light-emitting portion is installed in a reflector, near the center of the light-emitting tube. A compact high-pressure discharge lamp device characterized in that the wall thickness of the arc tube is maximized, and the wall thickness is continuously thinned as it approaches the end of the arc tube to a minimum total wall thickness of 1 mm or more.