JPH05325907A - Lighting device - Google Patents

Abstract

PURPOSE:To facilitate light distribution control of a lighting device and simultaneously prevent deterioration of light emitting efficiency (absorption or diffusion of radiated light) due to a substance adhering to the inside of a light emitting tube by reducing bending of an arc in lighting of a light source in the lighting device constituted in combination of a reflecting mirror and the light source where electrodes are disposed opposite to each other. CONSTITUTION:A lighting device is provided with a light source 1, a parabolic reflecting mirror 3, and a light reflector 4 having a parabolic surface. The light source 1 and the reflecting mirror 3 makes light radiated from the light source 1 parallel. The light reflector 4 reflects the light radiated from the light source 1 during lighting so as to focus it in the vicinity of the coldest portion of a light emitting tube of the light source 1. Consequently, a temperature at or near the coldest portion of a bulb of the light source is increased so as to remarkably reduce a difference in temperature inside of the light emitting tube, thus solving problems in the prior art.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a lighting device using a light source that supplies electric power from this electrode.

[0002]

2. Description of the Related Art Generally, when a discharge lamp having electrodes opposed to each other is lit horizontally (the axes formed by the electrodes are parallel to the ground), the arc moves vertically upward due to gas convection inside the arc tube. To bend. Due to the bending of the arc, the inner wall of the arc tube is unevenly heated, and the temperature of the upper part of the arc tube becomes higher and the temperature of the lower part becomes lower. In a lighting device using a reflecting mirror,
If the arc bends vertically upward as described above, it causes inconvenience in light distribution control. Further, for example, when a metal halide lamp is used as a light source, when the light source is turned on, the temperature inside the arc tube of the light source is low (the coldest part) and the temperature above is high, so it is sealed inside the arc tube. Also, a luminescent substance such as a metal compound adheres to the lower wall surface inside the arc tube having a low temperature without evaporating. As a result, a part of the irradiation light is absorbed or scattered by the attached substance in the arc tube, so that the light emission efficiency of the light source is lowered, that is, the light amount is reduced on the irradiated surface (not shown), or the irradiation light is changed. There is a problem in the amount of light and the color of light on the surface to be illuminated, such as uneven color.

As a method for improving these problems, Japanese Patent Application Laid-Open No. Hei 3
As shown in FIG. 6, in -194848, a thin film 15 that reflects only infrared rays is formed in the lower part near the arc of a short arc type metal halide lamp 13 combined with a reflector 14.
A method has been devised to improve the nonuniformity of the tube wall temperature of the short arc type metal halide lamp 13 by vapor-depositing or applying.

Further, in Japanese Patent Application No. 3-223862, by rotating the lamp itself while the lamp is lit, the temperature non-uniformity of the lamp tube wall is improved, and the metal iodide enclosed inside the arc tube is completely removed. A method of vaporizing has been devised.

[0005]

However, in Japanese Patent Laid-Open No. 3-194848, the temperature of the thin film becomes very high or the amount of ultraviolet radiation received by the thin film is high because the place where the thin film is vapor-deposited or applied is near the arc. The deterioration of the thin film is remarkable due to such a large amount, and the effect can be obtained only in an extremely short time. Further, in Japanese Patent Application No. 3-223862, since a device for rotating the lamp is required, the volume of the entire lighting device becomes large.

The illuminating device of the present invention has been made in view of the above-mentioned conventional problems, and provides a illuminating device which simplifies the configuration, remarkably reduces the degree of arc bending, and has its operation for a long time. The purpose of this is to simultaneously evaporate the adhering substance inside the arc tube of the light source to remove the decrease in the amount of light on the surface to be irradiated and the color unevenness of the irradiation light.

[0007]

In order to achieve this object, a lighting device according to the present invention has electrodes arranged opposite to each other, a light source for supplying electric power from both electrodes, and a part of the light source.
A reflecting mirror for reflecting the irradiation light from the light source, and a light reflecting means for reflecting the irradiation light from the light source or the reflected light from the reflecting mirror, and the light reflecting means from the light source or the reflecting mirror. At least a part of at least one of the irradiation light is reflected and condensed at or near the coldest part of the bulb of the light source, and the reflecting mirror is combined with the light reflecting means. It is a curved surface.

The reflecting mirror is a parabolic reflecting mirror,
And the light reflecting means is in the form of a single flat plate, the normal line of the light reflecting means is parallel to the optical axis of the reflecting mirror, and the light reflecting means is between the electrodes of the light source. It is arranged vertically below the point.

Further, the reflecting mirror is a parabolic reflecting mirror,
And the light reflecting means is a parabolic reflecting mirror having a focal point in the arc of the light source or in the vicinity of the arc, and the reflecting mirror is an elliptical reflecting mirror, and the light reflecting means is a bulb of the light source. The elliptic reflecting mirror has a focal point at the coldest portion or near the coldest portion of the bulb and the second focal point of the elliptic reflecting mirror.

Further, the reflecting mirror is a parabolic reflecting mirror or an elliptical reflecting mirror, and the light reflecting means is located in the arc of the light source or in the vicinity of the arc and in the coldest part of the light source or in the vicinity of the coldest part of the valve. It is an elliptical reflecting mirror having respective focal points.

Further, the light reflecting means is a spherical reflecting mirror having a sphere center between the bulb coldest part of the light source and the arc, and at least a part of the light reflecting means is wavelength selective transmission. It has a characteristic and a wavelength selective reflection characteristic.

[0012]

With this structure, the temperature of the coldest part of the light source and the vicinity of the coldest part of the bulb rise, so that the temperature difference inside the arc tube can be remarkably reduced. Therefore, the gas enclosed in the arc tube is reduced. Is almost eliminated, the degree to which the arc bends vertically upward can be reduced, and the light distribution control of the lighting device can be easily performed. Also,
A luminescent substance such as a metal compound enclosed inside the arc tube,
Almost all of it can be evaporated without adhering to the wall surface (coolest part) below the inner wall of the arc tube to improve the luminous efficiency, and it is possible to eliminate the decrease in the amount of light on the surface to be irradiated and the uneven color of the irradiation light. it can.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a lighting device according to a first embodiment of the present invention. In FIG. 1, the illumination device comprises a light source 1, a parabolic reflector 3, and a parabolic light reflecting means 4.
Both electrodes are located on the optical axis 2 of the parabolic reflector 3, and the parallel light emitted from the parabolic reflector 3 onto the illuminated surface (not shown) is reflected in a range other than the illuminated area. The means 4 is arranged. The light source 1 uses a discharge lamp (for example, a short arc type metal halide lamp), where the position of the arc generated between the electrodes of the light source 1 at the time of lighting is A, and the position of the coldest part of the bulb is B. The focal position of the light reflecting means 4 forming the paraboloid is set to the position B of the coldest part of the arc tube.

Next, regarding the illuminating device having the above structure,
The principle and operation will be described. In FIG. 1, the light traveling from the position A of the arc of the light source 1 to the parabolic reflector 3 is reflected by the parabolic reflector 3, and then the light of the parabolic reflector 3 is reflected. Irradiation is carried out in a direction parallel to the axis 2. Here, a part of the irradiation light (parallel light) from the parabolic reflecting mirror 3 enters the light reflecting means 4, is reflected by the light reflecting means 4, and then reaches the position B of the coldest part of the arc tube. Collected. Therefore, all the light incident on the light reflecting means 4 is focused on the position B of the coldest portion of the bulb, and the tube wall temperature at the position B of the coldest portion of the arc tube rises. As a result, the temperature difference in the arc tube is significantly reduced, and the difference in vapor pressure inside the arc tube is reduced, so that the convection generated in the gas inside the arc tube is almost eliminated, and the arc curvature can be significantly reduced. Moreover, it takes a long time to reduce the arc curvature.

Further, since the light emitting substance such as a metal compound attached to the vicinity of the coldest part inside the arc tube is evaporated, the light amount on the surface to be irradiated (not shown) is increased or the color unevenness of the irradiation light is eliminated. Further, deterioration of the arc tube (such as devitrification) can be reduced, reduction of the luminous flux of the light source due to deterioration of the arc tube can be prevented, and the life of the light source can be extended. Furthermore, since most of the substance enclosed in the arc tube of the light source evaporates, error factors in the design of the light source are reduced, and the design of the light source becomes easier.

In this embodiment, the reflecting mirror is a parabolic reflecting mirror 3 and the light reflecting means 4 is a parabolic reflecting mirror. However, as shown in FIG. 2, the reflecting mirror is an elliptical reflecting mirror 5 and a light reflecting means. It goes without saying that the same effect can be obtained even if 6 is an elliptical surface having a focal point at the second focal point 0 of the elliptic reflecting mirror 5 and a focal point B at the coldest portion of the light source 1.

FIG. 3 is a sectional view of a lighting device according to a second embodiment of the present invention. In FIG. 3, the illuminating device is composed of a light source 1, a parabolic reflector 7, and an ellipsoidal light reflecting means 8. Both electrodes of the light source 1 are on the optical axis 2 of the parabolic reflector 7, The light reflecting means 8 is arranged on the opening side of the object reflecting mirror 7.
The position of the arc generated between the electrodes of the light source 1 at the time of lighting is A, and the position of the coldest part of the bulb is B. The light reflecting means 8 forming an elliptical surface is installed at a position where the irradiation light from the parabolic reflecting mirror 7 is not obstructed, and the two focal points of the light reflecting means 8 are located at the arc position A and the coldest part of the arc tube. Is set to position B.

Next, regarding the illuminating device having the above structure,
The principle and operation will be described. In FIG. 3, the light traveling from the arc position A of the light source 1 to the parabolic reflector 7 is reflected by the parabolic reflector 7 and then radiated in a direction parallel to the optical axis 2 of the parabolic reflector 7. Then, the irradiated surface (not shown) is reached. On the other hand, from the position A of the arc of the light source 1, in addition to the above, the light reflecting means 8 is irradiated as direct light, reflected by the light reflecting means 8, and then condensed at the position B of the coldest part of the arc tube. It Therefore, all the light incident on the light reflecting means 8 is focused on the position B of the coldest part of the bulb, and therefore the position B of the coldest part of the arc tube.
And the temperature of the pipe wall near the coldest part rises. Therefore, since the temperature difference in the arc tube is significantly reduced, the difference in vapor pressure inside the arc tube is reduced, so that the convection generated in the gas inside the arc tube is almost eliminated, and the arc curvature can be significantly reduced. It can be done and the arc curvature can be reduced for a long time.

Further, since the light emitting substance such as a metal compound attached to the inner wall of the arc tube evaporates, the amount of light on the surface to be irradiated is not increased or the color unevenness of the irradiation light is eliminated. Further, deterioration of the arc tube (such as devitrification) can be reduced, reduction of the luminous flux of the light source due to deterioration of the arc tube can be prevented, and the life of the light source can be extended. Furthermore, since most of the substance enclosed in the arc tube of the light source evaporates, error factors in the design of the light source are reduced, and the design of the light source becomes easier. Further, the light reflecting means 6 is arranged at a position where the irradiation light from the parabolic reflecting mirror 5 is not obstructed,
Since only the direct light from the light source 1 is used, it is possible to reduce the curvature of the arc without reducing the irradiation light amount on the irradiation surface.

In this embodiment, the reflecting mirror is the parabolic reflecting mirror 7 and the light reflecting means 8 is an elliptical reflecting mirror.
It goes without saying that even if both the reflecting mirror and the light reflecting means are elliptical reflecting mirrors, the same effect can be obtained.

FIG. 4 is a sectional view of a lighting device according to a third embodiment of the present invention. In FIG. 4, the illuminating device comprises a light source 1, a parabolic reflector 9, and a spherical light reflecting means 10. Both electrodes of the light source 1 are on the optical axis 2 of the parabolic reflector 9, The means 10 has a wavelength-selective transmission characteristic and a wavelength-selective reflection characteristic of reflecting infrared light and transmitting other than infrared light.
And the parabolic reflector 9. The position of the arc generated between the electrodes of the light source 1 at the time of lighting is A, and the position of the coldest part of the bulb is B. The position of the center of the sphere of the light reflecting means 10 forming the spherical surface is set between the position A of the arc of the light source 1 and the position B of the coldest part of the bulb.

Next, the principle and operation of the illuminating device having the above structure will be described. In FIG. 4, the light traveling from the position A of the arc of the light source 1 to the parabolic reflector 9 is reflected by the parabolic reflector 9 and reaches the illuminated surface (not shown). In a part of the optical path between the light source 1 and the parabolic reflecting mirror 9, a light reflecting means 10 composed of a spherical surface is installed. Of the irradiation light from the light source 1 incident on the light reflecting means 10, infrared light is emitted. Is light reflecting means 10
It is reflected by and is focused on the bulb coldest part B of the light source 1. On the other hand, of the irradiation light from the light source 1 that has entered the light reflecting means 10, light other than infrared light passes through the light reflecting means 10, is reflected by the parabolic reflector 9, and then travels to the surface to be illuminated. To reach. Therefore, only the infrared light of the light incident on the light reflecting means 10 is focused on the position B of the coldest part of the bulb, and the position B of the coldest part of the bulb is not lowered without lowering the brightness of the illuminated surface. The temperature of the tube wall can be increased. Therefore, since the temperature difference in the arc tube is significantly reduced, the difference in vapor pressure inside the arc tube is reduced, so that the convection generated in the gas inside the arc tube is almost eliminated, and the arc curvature can be significantly reduced. It can be done and the arc curvature can be reduced for a long time.

Further, since the light emitting substance such as a metal compound attached near the coldest part of the arc tube is evaporated, the amount of light on the surface to be irradiated (not shown) is increased or the color unevenness of the irradiation light is eliminated. Further, deterioration of the arc tube (such as devitrification) can be reduced, reduction of the luminous flux of the light source due to deterioration of the arc tube can be prevented, and the life of the light source can be extended. Furthermore, since most of the substance enclosed in the arc tube of the light source evaporates, error factors in the design of the light source are reduced, and the design of the light source becomes easier. Further, since the light reflecting means 10 is provided with wavelength selective transmission characteristics and wavelength selective reflection characteristics, and the light reflecting means 10 is installed in the volume occupied by the parabolic reflecting mirror 9, visible light reaching the irradiated surface is reached. The degree of curvature of the arc can be reduced and the volume occupied by the entire lighting device can be reduced without reducing the amount of light.

Needless to say, the same effect can be obtained by using an elliptical reflecting mirror or a spherical reflecting mirror instead of the parabolic reflecting mirror 9 in this embodiment. FIG. 5 is a sectional view of a lighting device according to a fourth embodiment of the present invention. Figure 5
In FIG. 1, the illuminating device comprises a light source 1, a parabolic reflecting mirror 11, and a flat light reflecting means 12. Both electrodes of the light source 1 are on the optical axis 2 of the parabolic reflecting mirror 11, and the light reflecting means 12 Has wavelength selective transmission characteristics and wavelength selective reflection characteristics of reflecting infrared light and transmitting light excluding infrared light. The position of the arc generated between the electrodes of the light source 1 at the time of lighting is A, and the position of the coldest part of the bulb is B. The light reflecting means 12 forming a plane is arranged so as to be orthogonal to the optical axis of the parabolic reflecting mirror 11.

Next, the principle and operation of the illumination device having the above structure will be described. In FIG. 5, the light from the position A of the arc of the light source 1 is reflected by the parabolic reflector 11 and is emitted in the direction parallel to the light source. Part of this irradiation light is applied to the light reflecting means 12 provided in the middle of the optical path. Here, since the light reflecting means 12 has a characteristic of reflecting infrared light and transmitting other light, only infrared light of the reflected light from the parabolic reflector 11 is a light beam. The light is finally focused on the coldest part of the bulb of the light source 1 and the vicinity of the coldest part of the bulb through the same optical path as the incident light path to the reflecting means 12. On the other hand, the light excluding the infrared light that has entered the light reflecting means 12 passes through the light reflecting means 12 and then reaches a surface to be illuminated (not shown). Therefore,
With a very simple structure, it is possible to focus only the infrared light of the light incident on the light reflecting means 12 at the position B of the coldest part of the valve and its vicinity, so that the brightness of the irradiated surface is reduced. It is possible to easily increase the temperature of the pipe wall at the position B of the coldest part of the valve without the need. Therefore, since the temperature difference in the arc tube is significantly reduced, the difference in vapor pressure inside the arc tube is reduced, so that the convection generated in the gas inside the arc tube is almost eliminated, and the arc curvature can be significantly reduced. It can be done and the arc curvature can be reduced for a long time.

Further, since the luminescent substance such as a metal compound attached to the vicinity of the coldest part of the arc tube is evaporated, the amount of light on the surface to be irradiated (not shown) is increased or the color unevenness of the irradiation light is eliminated. Further, deterioration of the arc tube (such as devitrification) can be reduced, reduction of the luminous flux of the light source due to deterioration of the arc tube can be prevented, and the life of the light source can be extended. Furthermore, since most of the substance enclosed in the arc tube of the light source evaporates, error factors in the design of the light source are reduced, and the design of the light source becomes easier.

In this embodiment, the parabolic reflecting mirror 9 and the flat light reflecting means 12 are used.
It goes without saying that the same effect can be obtained even when a spherical reflecting mirror whose focal point is the center of the sphere and which is arranged on the optical axis 2 is used.

Further, the first to third embodiments of the present invention
Although the reflecting mirror and the light reflecting means are separated from each other in the above embodiment, it is needless to say that the same effect can be obtained even if the reflecting mirror and the light reflecting means form some kind of complex curved surface.

[0029]

As described above, according to the present invention, the following effects can be obtained. (1) Since the convection due to the temperature difference of the gas sealed inside the arc tube is almost eliminated, the degree to which the arc bends vertically upward can be significantly reduced. Therefore, the light distribution control of the lighting device can be facilitated, and the arc curvature can be reduced for a long time. (2) The luminous efficiency can be improved by almost evaporating the light emitting substance such as the metal compound enclosed in the inside of the arc tube, which is attached to the wall surface (the coldest part) below the inner wall of the arc tube. In addition, it is possible to eliminate a decrease in the amount of light on the surface to be irradiated and color unevenness of the irradiation light. (3) The deterioration of the arc tube (such as devitrification) can be reduced, the reduction of the luminous flux of the light source due to the deterioration of the arc tube can be prevented, and the life of the light source can be extended. (4) Since most of the substance enclosed in the arc tube of the light source evaporates, the error factors in the design of the light source are reduced, and the design of the light source becomes easier. (5) By using the configuration in which only the direct light from the light source is used, it is possible to reduce the degree of curvature of the arc without hindering the irradiation light from the reflecting mirror. (6) By providing the light-reflecting means with wavelength-selective transmission characteristics and wavelength-selective reflection characteristics, the degree of arc bending is reduced without reducing the amount of visible light reaching the surface to be illuminated, and a lighting device is provided. The volume occupied by the whole can be reduced. (7) By configuring the light reflecting means with a single flat plate, the configuration becomes very simple, and therefore, it becomes easy to reduce the degree of arc bending.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a lighting device of a first example of the present embodiment.

FIG. 2 is a cross-sectional view showing another example of the lighting device according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a lighting device according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a lighting device according to a third embodiment of the present invention.

FIG. 5 is a sectional view of an illumination device according to a fourth embodiment of the present invention.

FIG. 6 is a cross-sectional view of a conventional lighting device.

[Explanation of symbols]

 1 Light Source 2 Optical Axis 3, 5, 7, 9, 11 Reflector 4, 6, 8, 10, 12 Light Reflecting Means

Claims (8)

[Claims] 1. A light source in which electrodes are arranged to face each other, power is supplied from both electrodes, a reflecting mirror partially surrounding the light source and reflecting irradiation light from the light source, and irradiation light from the light source or A light reflecting means for reflecting the reflected light from the reflecting mirror, wherein the light reflecting means reflects at least a part of at least one of the light emitted from the light source or the reflecting mirror to cool the bulb of the light source. An illuminating device, characterized in that the light is focused near a cold spot or a coldest spot. 2. The illuminating device according to claim 1, wherein the reflecting mirror is a compound curved surface with the light reflecting means. 3. The reflecting mirror is a parabolic reflecting mirror, the light reflecting means is in the form of a flat plate, and the normal line of the light reflecting means is parallel to the optical axis of the reflecting mirror. The lighting device according to claim 1, wherein the light reflecting means is arranged below a midpoint between both electrodes of the light source. 4. The reflecting mirror is a parabolic reflecting mirror, and the light reflecting means is a parabolic reflecting mirror having a focal point at or near the coldest part of the light source. Or the illumination device according to 2. 5. The reflecting mirror is an elliptic reflecting mirror, and the light reflecting means is an elliptical reflecting mirror having a focal point at or near the coldest portion of the bulb of the light source and a second focal point of the elliptical reflecting mirror. The lighting device according to claim 1 or 2, characterized in that. 6. The reflecting mirror is a parabolic reflecting mirror or an elliptical reflecting mirror, and the light reflecting means focuses on the arc of the light source or in the vicinity of the arc and the coldest part of the light source or in the vicinity of the coldest part of the valve, respectively. The illuminating device according to claim 1 or 2, wherein the illuminating device is an elliptical reflecting mirror. 7. The illuminating device according to claim 1, wherein the light reflecting means is a spherical reflecting mirror having a sphere center between the coldest bulb of the light source and the arc. 8. The illumination device according to claim 1, wherein at least a part of the light reflecting means has a wavelength selective transmission characteristic and a wavelength selective reflection characteristic.