JP2008243624A - Electrodeless discharge lamp, and lighting fixture using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrodeless discharge lamp which can keep the most coldest portion at optimal temperature, while allowing to restrain degradation in strength of a projecting portion, and to provide a lighting fixture using such an electrodeless discharge lamp. <P>SOLUTION: The lighting fixture includes the electrodeless discharge lamp 1, a coupler 2 having an induction coil 20 which is arranged in proximity to the electrodeless discharge lamp 1 to excite discharge gas of the electrodeless discharge lamp 1 by generating high-frequency electromagnetic field using supplied high-frequency power, and a high-frequency power supply unit to supply the high-frequency power to the induction coil 20. The electrodeless discharge lamp 1 has a bulb 10 which is formed of a light-transmitting material and with which discharge gas and mercury are filled. On the bulb 10, a projecting portion 12 is integrally formed which constitutes a cone-shaped convex portion 12a at the front side of the bulb 10, while constituting a cone-shaped concave portion 12b at the rear side of the bulb 10. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrodeless discharge lamp that does not have an electrode in a bulb in which discharge gas and mercury are sealed, and emits light by applying a high-frequency electromagnetic field from the outside of the bulb to the inside of the bulb, and a lighting fixture using the same About.

  Conventionally, an electrodeless discharge lamp in which a discharge gas and mercury vapor are enclosed in a bulb (airtight container) formed of a translucent material has been proposed (see, for example, Patent Documents 1 to 4). When this type of electrodeless discharge lamp is lit, high frequency power is supplied to an induction coil arranged close to the bulb (by supplying a high frequency current) to generate a high frequency electromagnetic field by electromagnetic induction. Excites mercury atoms in the bulb and emits ultraviolet rays. When an electrodeless discharge lamp is used for illumination, a fluorescent material that absorbs ultraviolet rays and emits visible light is applied to the inner surface of the bulb.

  Since the electrodeless discharge lamp as described above has no structure inside the bulb, there is less non-lighting due to deterioration of the electrode, and it has a longer life than a general fluorescent lamp provided with a filament electrode. Has the advantage.

  By the way, in the electrodeless discharge lamp shown by patent document 1, 2, bismuth-indium-mercury amalgam is used as a supply source of mercury vapor. Such an amalgam has the advantage that a high light output can be obtained over a wide temperature range even if the ambient temperature changes. However, in order to achieve a high light output, the mercury vapor pressure in the bulb must be a predetermined value or more. There is a problem that it takes time for the temperature of the amalgam to reach a temperature necessary for the mercury vapor pressure to reach a predetermined value or more. For example, when the above-described bismuth-indium-mercury amalgam is used, it takes about 1 minute to secure 60% light output with respect to light output during stable lighting.

  Therefore, in the electrodeless discharge lamps disclosed in Patent Documents 3 and 4, pure mercury droplets are used as a source of mercury vapor in order to shorten the rise time. Mercury droplets can obtain a high mercury vapor pressure even at a lower temperature than the above-mentioned bismuth-indium-mercury amalgam, so the time until the mercury vapor pressure reaches the optimum value is short, and the start-up of the electrodeless discharge lamp is short. The time was able to be shortened. For example, when the above-described mercury droplet is used, a result that a light output of 50% with respect to the light output during stable lighting can be secured in 2 to 3 seconds is obtained.

  However, when the input power is large with respect to the volume of the bulb (for example, a high-load lamp) or when the ambient temperature is high, the mercury vapor pressure becomes too high because the bulb temperature becomes high, and the reverse However, there has been a problem that the light output decreases during stable lighting.

  Therefore, when using the above-mentioned mercury droplet, it is necessary to control the temperature of the coldest part (also called the coldest point) of the valve that affects the vapor pressure of mercury. Here, the coldest part is a part having the lowest temperature on the surface of the bulb, and the temperature is preferably about 40 degrees. Further, the coldest part varies depending on the lighting direction of the electrodeless discharge lamp. For example, in the case of BU (base up) that is lit with the base facing up, the tip of the bulb is the coldest part, and in the case of BD (base down) that is lit with the base facing down, the bulb directly above the base The base end is the coldest part.

In view of the above points, Patent Documents 3 and 4 propose that a hemispherical protrusion is formed on the bulb and this protrusion is used as the coldest part. Such a protrusion is formed by heating and melting a part of the wall of the bulb, extruding it outside, and then cooling and hardening it.
JP 7-272688 A Japanese Utility Model Publication No. 6-5006 JP 2001-325920 A JP 2005-346983 A

  By the way, when the tube wall load (the value obtained by dividing the rated power of the electrodeless discharge lamp by the surface area of the bulb) becomes large, the above-mentioned protrusion (that is, the coldest part) is maintained at a suitable temperature. It was necessary to increase the projecting dimension.

  However, since such a protrusion is formed by a part of the wall portion of the bulb, when the protrusion dimension is increased, the thickness of the protrusion is naturally reduced, and the strength of the protrusion is reduced. There was a problem that it was lowered and easily damaged.

  The present invention has been made in view of the above points, and an object of the present invention is to use an electrodeless discharge lamp capable of keeping the coldest part at a suitable temperature and suppressing a decrease in the strength of the protrusion, and the same. It is to provide the lighting equipment that was.

  In order to solve the above-described problems, the invention of claim 1 includes a bulb formed of a light-transmitting material and filled with a discharge gas and mercury. The bulb has a conical convex portion on the surface side of the bulb. In addition, a protrusion that forms a conical recess is integrally formed on the back side of the bulb.

  According to invention of Claim 1, since the projection part formed in the valve | bulb can be utilized as the coldest part, the coldest part can be maintained at suitable temperature. In addition, since the projecting portion constitutes a conical convex portion on the front surface side of the bulb and a conical concave portion on the rear surface side of the bulb, if the protruding dimension and the diameter (opening diameter) are the same, the conventional example Thus, since the surface area can be reduced and the thickness of the protruding portion can be increased compared to a hemispherical one or the like, a decrease in the strength of the protruding portion can be suppressed.

  According to a second aspect of the present invention, in the first aspect of the present invention, the protrusion is the same as the tip of the protrusion forming member having a tip formed in a conical shape in a state where a part of the valve is heated and melted. It is formed by pressing the part from the inside of the valve and pushing the part outward.

  According to the invention of claim 2, the shape accuracy of the protrusion can be improved as compared with the case where the protrusion is formed by feeding air or the like in a state where a part of the valve is heated and melted. It can suppress that the wall thickness becomes thin.

  According to a third aspect of the present invention, the electrodeless discharge lamp according to the first or second aspect of the present invention and the discharge of the electrodeless discharge lamp by generating a high-frequency electromagnetic field by being provided close to the electrodeless discharge lamp and supplying high-frequency power. An induction coil that excites gas and a high-frequency power supply unit that supplies high-frequency power to the induction coil are provided.

  According to the invention of claim 3, the coldest part can be maintained at a suitable temperature, and a decrease in the strength of the protrusion can be suppressed.

  The present invention has an effect that the coldest part can be maintained at a suitable temperature. Moreover, if the projecting dimensions are the same, the thickness of the projecting part can be made thicker than before, so that the strength of the projecting part is reduced. There is an effect that can be suppressed.

  As shown in FIG. 1, an electrodeless discharge lamp (electrodeless discharge lamp) 1 according to an embodiment of the present invention includes a bulb 10 in which discharge gas and mercury are enclosed, and a base end portion of the bulb 10 (the lower end in FIG. 1). Part) provided on the 10a side and a base 11 for fixing the valve 10 to the coupler 2 or the like.

  The bulb 10 is an airtight container formed in a hollow sphere shape (bulb shape) from a translucent material. In this embodiment, the bulb 10 is formed of quartz glass, and the inner diameter of the bulb 10 is set to 110 mm. The bulb 10 may be made of hard glass.

  Further, the valve 10 is formed by integrally forming a protrusion 12 at the top (tip) portion (upper end portion in FIG. 1). The protrusion 12 is formed in a hollow conical shape, and forms a conical convex portion 12a on the surface side (outer surface side) of the bulb 10, as shown in FIGS. 1 and 4A. In addition, a conical recess 12b is formed on the back surface side (inner surface side) of the bulb 10. Therefore, when the lighting direction of the electrodeless discharge lamp 1 is BU, the protrusion 12 is the coldest part.

  In forming such a protruding portion 12, as shown in FIG. 2, a protruding portion forming member 100 having a tip portion formed in a conical shape is used. Here, the tip end portion of the protrusion forming member 100 is formed in a curved surface shape having a radius of curvature R selected from a range of 1.0 mm to 4.0 mm.

  Then, as shown in FIG. 3, the protrusion 12 has a part of the tube wall of the bulb 10 (in this embodiment, the tip of the bulb 10) until it reaches a glass transition point or higher by a burner (oxygen burner or the like) 200. In a heated and melted state, it is formed by pressing the tip of the protrusion forming member 100 against the part from the inside of the valve 10 to push the part outward, and then cooling and hardening. Yes. That is, the protrusion 12 is formed by pushing out (bulging out) a part of the tube wall of the valve 10.

  In this way, for example, the shape accuracy of the protrusion 12 can be improved compared to the case where the protrusion 12 is formed by feeding air or the like in a state where a part of the valve 10 is heated and melted. It can suppress that the thickness of the projection part 12 becomes thin.

  On the other hand, a cylindrical hollow portion (cavity) 10 b in which the tip portion of the coupler 2 is disposed is recessed at the center portion of the base end portion 10 a of the bulb 10. A cylindrical exhaust pipe 13 is integrally projected from the bottom of the cavity 10b toward the opening side (that is, the base 11 side) of the cavity 10b. The inside of the exhaust pipe 13 communicates with the inside of the valve 10. Further, the length dimension of the exhaust pipe 13 is set to a value such that the front end portion (lower end portion in FIG. 1) of the exhaust pipe 13 protrudes outward from the cavity portion 10b. Furthermore, the length dimension of the bulb 10 (the dimension in the direction along the length direction of the hollow portion 10b) is such that the base end portion 10a becomes the coldest portion when the lighting direction of the electrodeless discharge lamp 1 is BD. In addition, the value is set such that the base end portion 10a is separated from the vicinity of the induction coil 20 that is the highest temperature in the valve 10 by a predetermined distance or more.

  The bulb 10 thus formed is filled with a discharge gas such as a rare gas such as argon or krypton. In addition, a phosphor 14 for applying ultraviolet light generated inside the bulb 10 to visible light is applied to the entire inner surface of the bulb 10. In this embodiment, since the bulb 10 is made of quartz glass, a protective film 15 for suppressing the reaction between the quartz glass and mercury is interposed between the phosphor 14 and the bulb 10.

  On the other hand, inside the exhaust pipe 13, a mercury supply unit 16 for supplying mercury to the inside of the valve 10 (evaporating the mercury and ensuring a necessary mercury vapor pressure), and 2 for fixing the mercury supply unit 16. Two cylindrical glass rods 17 are sealed in a state where the mercury supply unit 16 is sandwiched between the two glass rods 17. Further, the exhaust pipe 13 is provided with a mercury supply portion 16 and a protruding portion 13 a for regulating the position of the two glass rods 17, and the mercury supply portion 16 and the two glass rods 17 do not move in the exhaust pipe 13. I am doing so. In this embodiment, as the mercury supply unit 16, a Zn-Hg (zinc-mercury) amalgam having a weight of about 20 mg and a weight ratio of 50:50 is housed in a metal container made of iron-nickel alloy. Yes. Such a Zn-Hg amalgam has a characteristic that the relationship between temperature and mercury vapor pressure is close to that of a mercury drop as compared with the above-described bismuth-indium-mercury amalgam. Instead of Zn-Hg amalgam.

  Further, a dark place start assisting portion (dark place start assist flag) 18 made of cesium or the like is enclosed in the bulb 10 in order to compensate for the shortage of initial electrons in the dark place. The dark place start assisting portion 18 is attached to the other end of the holding portion 19 whose one end is locked by the protruding portion 13 b of the exhaust pipe 13.

  The base 11 is formed in a cylindrical shape with both ends opened using a synthetic resin. The valve 10 is fixed to the base 11 such that the base end side is inserted into the base 11 from one end opening (upper end opening in FIG. 1) of the base 11. The base 11 is configured to be fixed to the coupler 2, and when the base 11 is fixed to the coupler 2, the tip of the coupler 2 is positioned in the hollow portion 10 b of the valve 10. Yes.

  In the electrodeless discharge lamp 1 formed in this way, when the lighting direction is BU, the protrusion 12 is the coldest part, but when the lighting direction is BD, the base end portion of the bulb 10 10a becomes the coldest part.

  According to the electrodeless discharge lamp 1 of the present embodiment described above, since the protrusion 12 formed on the bulb 10 can be used as the coldest part, the coldest part can be kept at a suitable temperature.

  In addition, the protrusion 12 constitutes a conical convex portion 12a on the front surface side of the bulb 10, and constitutes a conical concave portion 12b on the back surface side of the bulb 10, so that the protruding dimension (height) and diameter (open) If the diameter is the same, the surface area of the protrusion 12 is smaller than that of a hemispherical or cylindrical shape as in the conventional example, and the thickness of the protrusion 12 can be increased. Reduction can be suppressed.

  In order to confirm this, a plurality of protrusions 12 in this embodiment shown in FIG. 4A and a plurality of protrusions 12 of a comparative example (conventional example) shown in FIG. 4B are formed. The thickness of the tube wall of the bulb 10 and the wall thickness t of the protrusion 12 before the formation were measured. In the following description, in order to distinguish the protrusion 12 in this embodiment shown in FIG. 4A from the protrusion 12 of the comparative example shown in FIG. The protrusion 12 is indicated by reference numeral 12A, and the protrusion 12 of the comparative example is indicated by reference numeral 12B.

  In this measurement, the protrusion dimension H is 12 mm, and the diameter φ is 28 mm. When forming the protrusion 12A, the diameter is 18 mm and the top radius of curvature R is 1.5 mm, 3.0 mm, and 5.0 mm. The protrusion forming member 100 is used. Further, in forming the protruding portion 12B, the columnar protruding portion forming member 300 shown in FIG. 5 is used instead of the protruding portion forming member 100 shown in FIG. 2, and the others are used when forming the protruding portion 12A. It is the same. The diameter of the protrusion forming member 300 is equal to that of the protrusion forming member 100.

  In other words, the protrusion 12B is a tip of a cylindrical protrusion-forming member 300 as shown in FIG. 5 in a state where a part of the tube wall of the bulb 10 is heated and melted by the burner 200 until the glass transition point is reached. It is formed by pressing the part against the part from the inside of the valve 10 to push the part outward, and then cooling and hardening.

  The graph shown in FIG. 6 was obtained from the measurement results. In the graph, A indicates the protrusion 12A in the present embodiment, and B indicates the protrusion 12B of the comparative example.

  As is apparent from the graph shown in FIG. 6, it can be seen that the protrusion 12A in the present embodiment is thicker than the protrusion 12B of the comparative example.

  Further, for each of the electrodeless discharge lamp 1 of the present embodiment and the electrodeless discharge lamp 1 having the protrusion 12B of the comparative example, the temperature of the protrusion 12 (that is, the temperature of the coldest part) and the luminous efficiency (lm / W). As a result, the results shown in Table 1 below were obtained. In this measurement, the protrusion 12A is formed using the protrusion forming member 100 having a diameter of 18 mm and the curvature radius R of the top is 3.0 mm, and the protrusion 12B is formed using the protrusion forming member 300 having a diameter of 18 cm. The projecting dimension H of each projection 12 is 12 mm, and the diameter φ is 28 mm. The lighting direction of the electrodeless discharge lamp 1 was BU (upper cap). In the table, A indicates the electrodeless discharge lamp 1 of the present embodiment, and B indicates the electrodeless discharge lamp 1 of the comparative example.

  As is apparent from Table 1, if the protruding dimension H and the diameter φ are the same, the electrodeless discharge lamp 1 of the present embodiment can lower the temperature of the coldest part and improve the luminous efficiency. Was also confirmed.

  The electrodeless discharge lamp 1 of this embodiment is used for a lighting fixture as shown in FIG. 7, for example. The lighting fixture shown in FIG. 7 generates a high-frequency electromagnetic field by being disposed in proximity to the electrodeless discharge lamp 1 of the present embodiment and the electrodeless discharge lamp 1 to generate a high-frequency electromagnetic field, thereby discharging the electrodeless discharge lamp 1. A coupler 2 having an induction coil 20 that excites gas (see FIG. 1) and a lighting circuit unit (ballast) 3 having a high-frequency power supply unit (not shown) that supplies high-frequency power to the induction coil 20 are provided.

  As shown in FIG. 1, the coupler 2 includes an induction coil 20 that generates a high-frequency electromagnetic field when high-frequency power is supplied and excites the discharge gas sealed in the bulb 10. In the present embodiment, since a high frequency current having a relatively low frequency of about several hundred kHz is used as a high frequency current to be passed through the induction coil 20, the coupler 2 is a cylindrical core around which the induction coil 20 is wound. 21 is provided. Such a core 21 is formed of, for example, ferrite, and has an outer shape smaller than the inner diameter of the hollow portion 10b, an inner diameter larger than the outer diameter of the exhaust pipe 13, and longer than the exhaust pipe 13. ing. Therefore, when the coupler 2 is inserted into the cavity 10 b, the exhaust pipe 13 is disposed inside the core 21.

  The ballast circuit unit 3 converts, for example, an AC voltage obtained from a commercial power source into a predetermined high-frequency voltage and supplies high-frequency power to the induction coil 20 of the coupler 2 through the feeder line 4, It is constituted by a dimming control circuit (not shown) that controls on / off of the output of the high-frequency power supply unit according to the duty ratio instructed from the pulse generator. Note that a well-known one can be employed as the stable circuit unit 3, and thus detailed description thereof is omitted.

  In the lighting fixture described above, when a high frequency current is passed through the induction coil 20, a high frequency electromagnetic field is generated around the induction coil 20. Electrons in the bulb 10 are accelerated by the high-frequency electromagnetic field, and the accelerated electrons collide with mercury atoms, so that the mercury atoms are ionized (the ionization of the mercury atoms is a Penning effect caused by a discharge gas such as argon). Also occurs). As a result, discharge is started, and the discharge is maintained by repeating the ionization as described above, and plasma is generated in the bulb 10 soon. When plasma is generated, most of the energy generated by the high-frequency electromagnetic field is consumed by electrons, and the electrons accelerated by the high-frequency electromagnetic field collide with the mercury atoms, thereby ionizing or exciting the mercury atoms. When the excited mercury atom returns to the ground state, light having a wavelength corresponding to the energy difference between the excited state and the ground state, that is, ultraviolet light (ultraviolet light having a wavelength of 254 nm and ultraviolet light having a wavelength of 185 nm) is emitted. The Such ultraviolet rays are converted into visible light by the phosphor 14 applied to the inner surface of the bulb 10 and emitted outward from the bulb 10.

  According to such a lighting fixture, by adopting the electrodeless discharge lamp 1 of the present embodiment, the coldest part can be maintained at a suitable temperature, and the decrease in the strength of the protrusion 12A can be suppressed. Become.

  By the way, as shown in FIG. 8, the electrodeless discharge lamp 1 of this embodiment has a dome-shaped reflecting plate 5 that reflects light emitted from the electrodeless discharge lamp 1 and an opening of the reflecting plate 5 that is closed. The present invention can also be applied to a lighting fixture having a translucent plate (front panel) 6 attached to the reflecting plate 5. In this case, the electrodeless discharge lamp 1 is surrounded by the reflecting plate 5 and the translucent plate 6 and is almost sealed, but the temperature of the coldest portion can be efficiently lowered by the protrusion 12A. The coldest part can be maintained at a suitable temperature, and a decrease in the strength of the protrusion 12A can be suppressed.

  In addition, the shape of the electrodeless discharge lamp 1 of this embodiment is an example to the last, and is not the meaning limited to this. Further, the shape of the protrusion 12A need not be a conical shape in a strict sense, and the same effect can be obtained if it can be regarded as a substantially conical shape.

  Moreover, the electrodeless discharge lamp 1 of this embodiment is employable not only for lighting fixtures as shown in FIGS. 7 and 8, but also for various lighting fixtures.

It is a schematic sectional drawing of the electrodeless discharge lamp of one Embodiment of this invention. It is an external view of a projection part forming member. It is explanatory drawing of the formation method of a projection part. (A) is sectional drawing of the projection part in this embodiment, (b) is sectional drawing of the projection part of a comparative example. It is an external view of the projection part formation member used for formation of the projection part of a comparative example. It is a graph of the comparison result of the electrodeless discharge lamp of this embodiment, and a prior art example. It is explanatory drawing of a lighting fixture provided with the electrodeless discharge lamp of one Embodiment of this invention. It is explanatory drawing of the other example of the lighting fixture in the same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrodeless discharge lamp 2 Coupler 10 Bulb 12 Projection part 12a Projection part 12b Concave part 20 Inductive coil 100 Projection part formation member

Claims (3)

  A bulb formed of a light-transmitting material and filled with discharge gas and mercury is provided. The bulb has a conical convex portion on the front surface side of the bulb and a conical concave portion on the back surface side of the bulb. An electrodeless discharge lamp characterized in that the portion is integrally formed.   The protrusion is in a state where a part of the bulb is heated and melted, and the tip of the protrusion-forming member whose tip is formed in a conical shape is pressed against the part from the inside of the valve to 2. The electrodeless discharge lamp according to claim 1, wherein the electrodeless discharge lamp is formed by extruding outward.   An electrodeless discharge lamp according to claim 1, and an induction coil that is disposed in proximity to the electrodeless discharge lamp and generates a high-frequency electromagnetic field by exciting a discharge gas of the electrodeless discharge lamp by being supplied with high-frequency power. And a high-frequency power supply unit that supplies high-frequency power to the induction coil.

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