JP2007115547A - Discharge lamp and light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode structure of a discharge light emitting lamp using plasma discharge and a light emitting device using the same which are effective in improving light emitting efficiency. <P>SOLUTION: This discharge light emitting lamp comprises a discharge bulb 3 for generating discharge light emission using plasma discharge which is generated by receiving high frequency electromagnetic waves, and a wave guide 4 having an outer conductor 4a and an inner conductor 4b for transmitting the electromagnetic waves into the discharge bulb 3. The top 5 of the inner conductor 4b is made to protrude into a discharge space of the discharge bulb 3, thereby directly conducting the electromagnetic waves into the discharge space. In the case of application to an electrodeless lamp, the electromagnetic waves are effectively conducted into the discharge bulb by making the top of the inner conductor protrude into the inside space or up to near the inside wall of the discharge bulb. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for increasing the efficiency of a discharge lamp having an electrode for introducing an electromagnetic wave in a discharge tube (arc tube) or an electrodeless discharge lamp having no electrode in the discharge tube.

  There are known electrodeless discharge lamps that do not have electrodes in the discharge space, and are not subject to lamp life limitations due to exhaustion of filaments or electrodes, there is no heat loss from the electrodes, and there are no enclosures in the discharge tube. It is not necessary to consider the reaction with the electrode material, and a luminescent substance suitable for improving efficiency can be used.

  By the way, there is a difficult problem to be solved for practical use in order to realize a small light source that requires light distribution control, such as lighting for automobiles. For example, in a method using a cavity resonator, when a microwave is oscillated by a magnetron and an electrodeless discharge tube in the cavity resonator is caused to emit light via a waveguide, the minimum dimension of the cavity resonator is an electromagnetic wave. It is determined in principle by the frequency.

  In addition, it is necessary to solve the problem of electromagnetic noise generated accompanying the use of high-frequency current, and the method of installing an electromagnetic shielding means (for example, a wire mesh etc.) reduces efficiency and deteriorates light distribution performance. There are concerns about the impact. That is, it is desirable not to arrange a shield, a coil or the like that blocks light around the discharge tube.

  As a configuration of a small electrodeless discharge lamp in response to such a request, there is known a lamp in which a discharge tube is arranged at the end of a coaxial tube and a luminescent substance in the discharge tube is excited by high-frequency electromagnetic waves. (For example, refer to Patent Document 1). In other words, a configuration in which a strong radio frequency electric field is generated locally from the slit formed at the end of the coaxial tube and an electromagnetic wave shielding effect is obtained using the surface wave plasma excited thereby is coaxial. Since the tube is not limited in size by frequency (also referred to as having no cut-off frequency), a discharge tube having the same size as the diameter of the coaxial tube can be used.

JP 2003-197156 A

  By the way, in the conventional electrodeless discharge lamp, it has been found that the following problems need to be solved in order to further increase the luminous efficiency.

(1) In conventional discharge tubes, electromagnetic waves are introduced through the bottom surface of the tube, so joule loss is large (a material such as ceramic or quartz glass is used for the discharge tube, and heat is generated at the bottom surface of the tube on the waveguide side. Loss is a problem.)
(2) Loss due to heat conduction increases when the contact area between the discharge tube and a conductor portion (external conductor or internal conductor) having a large heat capacity is large. (3) In a conventional discharge lamp, the discharge arc runs along the tube wall. The electrons in the plasma are easily lost due to diffusion and recombination, and the arc temperature is difficult to increase (that is, the high efficiency and high brightness are hindered).
(4) To increase luminous efficiency, it is necessary to efficiently introduce electromagnetic waves into the discharge tube.

  Therefore, an object of the present invention is to provide an electrode structure that is effective for improving luminous efficiency in a discharge lamp using discharge luminescence by plasma and a light source device using the same.

  The first of the present invention is a discharge lamp using a discharge tube that discharges and emits light by plasma generated by receiving high-frequency electromagnetic waves, and a waveguide having an outer conductor and an inner conductor for transmitting electromagnetic waves. The tip of the inner conductor protrudes into the discharge space of the discharge tube, and the inner conductor is integrated with the first conductive member integrated with the discharge tube and the second conductive member provided in the waveguide. The first conductive member and the second conductive member are arranged in close proximity to each other with the discharge tube attached to the end of the waveguide. It is.

  The second aspect of the present invention is a discharge lamp using a discharge tube that discharges light by plasma generated by receiving high-frequency electromagnetic waves, and a waveguide having an outer conductor and an inner conductor for transmitting the electromagnetic waves. , The tip of the inner conductor protrudes to a position close to the inner space or tube wall of the discharge tube, and a protrusion formed integrally with the discharge tube is interposed between the tip and the outer conductor. It has been done.

  Therefore, in these present inventions, electromagnetic waves can be efficiently introduced into the discharge space from the end portion of the inner conductor, so that the light emission efficiency can be increased as compared with the conventional configuration.

  According to the present invention, increasing the luminous efficiency of the discharge tube is effective for increasing the brightness or reducing the size.

  For example, in the configuration in which the tip portion of the inner conductor protrudes into the discharge tube, electromagnetic waves can be directly introduced into the discharge tube, and compared with a mode in which electromagnetic waves are introduced from the tube wall (bottom surface) of the discharge tube. Loss can be reduced.

  In addition, according to the configuration in which the tip of the inner conductor (first conductive member) is exposed and positioned in the discharge space, the position of the discharge arc is fixed and stabilized. A desirable property in terms of surface is obtained. In addition, the distance between the discharge arc and the tube wall is kept constant, which is advantageous in terms of efficiency and life. In other words, the problem with conventional configurations and general cavity resonator type electrodeless discharge lamps is that the efficiency decreases due to the arc position becoming unstable and close to the tube wall (that is, plasma In the present invention, this problem is overcome, and stability and long life are ensured. be able to.

  Regarding the point that the range of material selection for the inner conductor is narrowed due to the necessity of avoiding the reaction between the enclosed substance in the discharge tube and the inner conductor, the state where the tip of the inner conductor is embedded in the tube wall of the discharge tube In other words, it is only necessary to adopt a configuration that is positioned in the discharge space while being covered with the tube material.

  In addition, in order to reduce the loss due to heat transfer, in a configuration using a plurality of conductive members for the inner conductor, the heat conduction from the discharge tube to the inner conductor is reduced by reducing the outer diameter of the tip of the inner conductor. It is preferable to reduce the loss due to.

  In the form in which the inner conductor is composed of the first conductive member integrated with the discharge tube and the second conductive member provided in the waveguide, the discharge tube is attached to the end of the waveguide. In this state, the first conductive member and the second conductive member are arranged in close proximity to each other. Thereby, the loss by the direct heat transfer from the 1st conductive member to the 2nd conductive member can be reduced. Moreover, the structure which integrated the 1st electroconductive member with the discharge tube can introduce | transduce electromagnetic waves into a discharge tube efficiently.

  In order to further increase the luminous efficiency in the above configuration, it is preferable to attach another conductor as an auxiliary electrode at a position facing the tip of the inner conductor in the tube wall of the discharge tube, and one end of the conductor is exposed. What is necessary is just to comprise so that it may be located in a discharge space in the state which was buried or the state embed | buried under the tube wall of the discharge tube. For example, if this conductor is used as a starting electrode, advantages such as easy starting of the discharge tube by applying an electric field to the discharge tube can be obtained.

  The configuration in which the tip of the inner conductor protrudes to a position close to the inner space or tube wall of the discharge tube is suitable for an electrodeless discharge lamp, and the discharge is between the tip of the inner conductor and the outer conductor. By interposing a protrusion formed integrally with the tube, a sufficient creepage distance between the inner conductor and the outer conductor can be secured. In other words, discharge is likely to occur in the arrangement where the conductors are close to each other, but the effect of preventing abnormal discharge can be obtained by interrupting the discharge by interposing a protrusion formed integrally with the discharge tube between the conductors. Original light emission can be performed reliably.

  In application to a light source device including a power source for generating electromagnetic waves and a waveguide for transmitting electromagnetic waves to a discharge tube, a discharge lamp having an electrode for introducing electromagnetic waves in the discharge tube, or an electrode in the discharge tube This is effective in improving the light emission efficiency of an electrodeless discharge lamp that does not have a light source. That is, it is possible to increase the brightness of the discharge lamp, or it is possible to reduce the power and reduce the size in the case where the brightness comparable to the conventional one is obtained.

  The present invention can be applied to various light sources that require light distribution control. For example, in light sources for vehicle headlamps and sign lights, light sources such as road lighting and traffic lights, store display lighting, light sources for projector devices, etc., the size of the light emitting part is reduced, the luminance is increased, the luminance distribution is made uniform, etc. Can be provided, and it is a small light source such as a cylindrical shape or a spherical shape, and a configuration in which a member that shields or diffuses light is not disposed around the light source can be provided.

  FIG. 1 is an explanatory view showing a basic configuration example of a light source device using a discharge lamp according to the present invention.

  The light source device 1 includes a power supply unit 2, a discharge tube 3, and a waveguide 4 for transmitting electromagnetic waves.

  The waveguide 4 connecting the power supply unit 2 and the discharge tube 3 has an outer conductor 4a and an inner conductor 4b. For example, a coaxial in which the outer conductor 4a is arranged on the outer periphery of the conductor with the inner conductor 4b as a central conductor. Tubes and coaxial cables are used. In consideration of the degree of freedom in arrangement, it is preferable to use a material having high flexibility.

  The power supply unit 2 for generating high-frequency electromagnetic waves includes, for example, an oscillation unit that generates electromagnetic waves in a microwave band (1 to 100 GHz), and uses a magnetron. It is possible to use a high-frequency amplifier device configured by using a bipolar transistor or the like.

  The discharge tube 3 is formed in a hollow cylindrical shape using a transparent material such as ceramic or synthetic quartz glass, for example, and a predetermined encapsulated substance (a gas such as xenon or argon, a metal iodide such as NaI or ScI3) is contained in the tube , Metal bromide, etc.). Moreover, the form which apply | coats a fluorescent substance to the inner surface or outer surface of a discharge tube as needed is possible. In addition, although a torus shape having a center hole, a double tube structure, or a structure in which a concave portion is formed in the center of a cylindrical shape may be used, when a discharge tube is attached to the tip of a coaxial tube or a coaxial cable, A shape that can reduce the outer diameter of the discharge tube and can be miniaturized, such as a cylindrical tube or a hollow sphere, is preferable.

  In this configuration example, the tip 5 of the inner conductor 4b protrudes into the discharge space of the discharge tube 3, and constitutes an electromagnetic wave irradiation unit together with the end of the outer conductor 4a. That is, the end of the waveguide 4 to which the discharge tube 3 is attached has a function as a launcher for introducing electromagnetic waves into the discharge tube 3.

  Reflected wave detection means 6 is provided on the waveguide 4 to detect a reflected wave propagating from the discharge tube 3 to the power supply unit 2 side. Then, the measurement result is sent to the output control means 7.

  The output control means 7 controls the output of the power supply unit 2 to minimize the reflection loss by adjusting the impedance matching based on the measurement information from the reflected wave detection means 6. That is, in a configuration in which electromagnetic waves are transmitted from the power supply unit 2 to the discharge tube 3 using a coaxial tube or a coaxial cable, the level of the reflected wave becomes large as it is in the case of a high frequency, so that the discharge tube 3 can be efficiently supplied with power. Or the increase in power loss becomes a problem. Therefore, power is supplied to the discharge tube 3 by suppressing reflected waves using a device for impedance matching between the power supply unit 2 and the discharge tube 3 (for example, a matching device using a sleeving tuner or the like). Can be performed efficiently. Specifically, the LC component of the waveguide circuit (L: inductive component, C: capacitive component) is adjusted based on the detection information of the reflected wave so that the reflection loss is minimized (the reflected wave is sufficiently reduced). Matching is performed between the output impedance of the power supply unit 2 and the impedance of the discharge tube 3.

  For example, in a configuration in which a magnetron, an isolator, an attenuator, a directional coupler, a sleeving tuner, a coaxial waveguide converter, and a coaxial tube are sequentially connected to the discharge tube, the tip of the coaxial tube functions as an antenna . The isolator serves to prevent the reflected wave from returning to the magnetron, and the directional coupler is a device for allowing the electromagnetic wave to travel only in one direction.

  A strong high-frequency electric field generates high-density plasma in the discharge tube and shifts to a lighting state, and the high-frequency electric field from the coaxial tube becomes a traveling wave and is introduced into the discharge tube to continue lighting.

  Since a high-frequency electric field is not allowed to enter the high-density plasma (the density at this time is referred to as “blocking density”), the high-frequency electric field becomes a surface wave mode between the dielectric discharge tube and the plasma. It propagates while generating plasma (this is called "surface wave plasma").

  Even when a high-frequency electric field is applied only to a part of the discharge tube, the plasma is uniformly generated in the discharge tube by the surface wave plasma. Therefore, the shape of the discharge tube is regulated to the shape required for light distribution control. For example, the entire shape can emit light (that is, a light source suitable for light distribution control can be realized).

  In the form using surface wave plasma, plasma is uniformly generated in the discharge tube, and the temperature distribution in the discharge tube becomes uniform, which contributes to improvement in efficiency.

  A semiconductor element such as a diode is used to detect electromagnetic waves, and incident waves and reflected waves can be measured by the detected current. For example, in the transition period from the start of lighting of the discharge tube to the steady lighting by attaching each detecting element for incident and reflection to the directional coupler and adjusting the impedance matching based on the detection result Electric power can be supplied to the discharge tube without loss. In addition, it is possible to realize efficient and stable lighting by suppressing reflection loss with respect to characteristic changes caused by aging and life.

  In this example, the power supply unit 2 and the output control means 7 are shown separately. However, the present invention is not limited thereto, and the output control means 7 is integrated so as to be included in the power supply part (that is, the power supply unit itself). May have an output control function).

  About the discharge lamp which concerns on this invention, the structure form shown below is mentioned.

(I) Configuration in which the tip of the inner conductor protrudes into the discharge space (internal space) of the discharge tube (II) Configuration in which the tip of the inner conductor protrudes to a position close to the inner space of the discharge tube or the tube wall.

  For example, quartz glass or ceramic is used as the material of the discharge tube. First, a configuration example using quartz glass will be described with reference to FIGS. 2 to 8.

  FIG. 2 is a cross-sectional view of a main part illustrating the discharge lamp having the configuration (I).

  The discharge lamp 8 has a discharge tube 3A attached to the end of the waveguide 4A, and the waveguide 4A is connected to a power source (not shown) via a coaxial cable or the like.

  The outer diameter of the discharge tube 3A is the same as or smaller than the outer diameter of the waveguide 4A. In this example, the discharge tube 3A is a cylindrical tube 9, and one end thereof is extended from the tube wall. And a cylindrical sealing portion 10 protruding outward. When quartz glass is used as the tube material, the sealing portion 10 is formed by a shrink seal method or a pinch seal method.

  A conductive member 11 is partially embedded in the sealing portion 10, and one end thereof is located in the internal space (discharge space) 12 of the discharge tube 3 </ b> A. The conductive member 11 constitutes an inner conductor 13 together with a later-described conductive member (14). In this example, the conductive member 11 is a thin wire conductor (metal rod or the like) having an outer diameter of about 0.2 to 0.4 mm. The portion 11a closer to the tip corresponds to the tip 5 described above, and serves as an antenna for introducing electromagnetic waves into the tube (that is, an electrode as a current path such as a conventional discharge lamp with an electrode) Different.)

  As another conductive member 14 constituting the internal conductor 13, for example, a metal rod or metal pipe, or a member in which a conductive film is formed on the inner peripheral surface of quartz glass is used. In this example, a concave portion 14a is formed at one end portion of the conductive member 14 using a bulk material, and the conductive member 14 is attached in a state where one end portion of the sealing portion 10 is inserted into the concave portion 14a.

  As the outer conductor 15 constituting the waveguide 4A, a member or the like in which a conductive film is formed on the outer peripheral surface of a metal material or quartz glass is used. In this example, the end portion 15a of the outer conductor 15 formed into a cylindrical shape using a bulk material has a configuration bent inward, and as shown by a protruding amount of a dimension "d" in the drawing, The tip of the portion 11a of the conductive member 11 protrudes toward the discharge tube 3A with respect to the end 15a.

  A dielectric 16 using, for example, quartz glass or a ceramic pipe is interposed between the inner conductor 13 and the outer conductor 15 to insulate the conductors. Note that it is preferable to use a material having low thermal conductivity for the dielectric 16 in terms of improving efficiency.

  In this example, since the front end of the conductive member 11 constituting the inner conductor 13 is exposed and positioned in the discharge space 12 and the position of arc discharge is fixed and stabilized, the automotive headlamp It is useful when applied to a light source that requires a light distribution performance as described above. However, the range of the latter material selection is limited because it is necessary to prevent the reaction between the substance (Na, Sc, etc.) enclosed in the tube and the material used for the conductive member 11. Therefore, as shown in FIG. 3, the material used for the electrode can be arbitrarily selected by making the tip of the inner conductor covered with the tube material.

  That is, the discharge lamp 17 shown in FIG. 3 is different from the discharge lamp 8 shown in FIG. 2 in that the tip 11a of the internal conductor is embedded in a part of the tube wall 18 of the discharge tube 3B (see the protruding portion 18a). It is located in the discharge space 12 in a state where

  The conductive member 11 is protected by being completely covered with the tube material, and there is an advantage that the conductive member 11 is not affected by deterioration, discoloration, or the like due to the reaction with the luminescent material.

  Also in this example, the inner conductor 13 is constituted by using a plurality of conductive members (11, 14), and the outer diameter of the tip of the conductive member (11) is different from that of the other conductive members (14). ) Is smaller than the outer diameter. That is, it is possible to reduce the amount of heat that escapes to another conductive member by reducing the diameter of the tip.

  As described above, in the configuration in which the internal conductor 13 includes the first conductive member 11 and the second conductive member 14, the first conductive member 11 and the second conductive member 14 are It is preferable that the heat transmitted from the conductive member 11 to the conductive member 14 is cut off or reduced by separating and arranging both members in close proximity. That is, in the case where the conductive members 11 and 14 are electrically and thermally connected, heat is directly transmitted from the tip of the conductive member 11 to the conductive member 14. By separating the conductive members 11 and 14 as described above, it becomes possible to suppress the influence of heat transfer. In the above example, the end portion of the conductive member 11 (the lower end portion in the figure) is disposed adjacent to the concave portion 14a of the conductive member 14, and the sealing portion 10 is interposed between the two members. A tube material (in this example, quartz glass is used and has low thermal conductivity) is interposed. The electromagnetic wave propagates from the conductive member 14 to the conductive member 11 without any trouble even if the two members are not physically connected, but the two members are thermally insulated from each other, and the influence of heat transfer Is shut off.

  As a result of the heat conduction loss being reduced by such a heat insulating structure related to the inner conductor, the efficiency can be improved.

  In addition, about the coupling | bonding method of the sealing part 10 containing the electroconductive member 11, and the electroconductive member 14, it is not restricted to the method by insertion or engagement, A screw groove is formed in the one, and the other screw part is attached. For example, a method of forming and fastening both of them may be used, or they may be fixed in a non-removable state by adhesion or the like.

  In order to further increase the luminous efficiency, it is effective to attach another conductor as an auxiliary electrode at the position facing the tip of the inner conductor on the tube wall of the discharge tube as shown in FIGS. .

  FIG. 4 shows an example in which the conductor 21 is provided at a position facing the end of the discharge tube 3 </ b> C, that is, the tip 11 a of the conductive member 11 in the configuration shown in FIG. 2.

  In the discharge lamp 19, a part of the conductor 21 protruding into the discharge space 12 from the tube wall 20 above the discharge tube is exposed, and the conductor 21 is coaxial with the central axis of the conductive member 11. Is located.

  The dimension “D” shown in the figure indicates the distance between the upper end position of the conductor 21 and the outer conductor 15.

  FIG. 5 shows an example in which the conductor 24 is provided at a position facing the end of the discharge tube 3D, that is, the tip 11a of the conductive member 11 in the configuration shown in FIG.

  Also in the discharge lamp 22 shown in this example, a part of the conductor 24 protruding into the discharge space 12 from the tube wall 23 at the top of the discharge tube is exposed, and the conductor 24 is coaxial with the central axis of the conductive member 11. Located on the top.

  FIG. 6 shows an example in which the conductor 27 is provided at a position facing the end of the discharge tube 3E, that is, the tip 11a of the conductive member 11 in the configuration shown in FIG.

  In the discharge lamp 25 shown in this example, a conductor 27 protruding into the discharge space 12 from the tube wall 26 at the top of the discharge tube is embedded in a part 26a of the tube wall 26, and the conductor 27 is a conductive member. 11 is located coaxially with the central axis. That is, the conductor 27 is protected by being completely covered with the pipe material, and an advantage is obtained that the conductor 27 is not affected by the reaction with the encapsulated substance.

  4 to 6, if the conductors (21, 24, 27) protruding into the discharge space 12 are used as starting electrodes, a strong electric field can be applied to the discharge tube. Can be started. That is, it is not necessary to apply a Tessler coil or the like to the discharge tube from the outside at the start. The application of the present invention is not limited to the above-described configuration example, and can be implemented in various forms such as a configuration in which an internal conductor is penetrated into the discharge tube.

  Next, a configuration example (II) in the case of using quartz glass will be described with reference to FIGS.

  FIG. 7 illustrates an example of the electrodeless discharge lamp in which the tip of the inner conductor constituting the waveguide protrudes to a position close to the tube wall of the discharge tube 3F.

  In the discharge lamp 28, a portion 29a of the tube wall 29 of the discharge tube 3F protrudes toward the discharge space 12 so that the portion is depressed when viewed from the waveguide 4B side. And the cylindrical protrusion (or leg part) 29b formed in the circumference | surroundings protrudes to the waveguide 4B side.

  The waveguide 4B has an inner conductor 30 and an outer conductor 31, and a dielectric 32 such as quartz glass is interposed between them.

  For the internal conductor 30, a member such as a metal rod, a metal pipe, or a member having a conductive film formed on the surface thereof such as quartz glass is used. In this example, a bulk material is used, and a portion 30a near the tip has a smaller diameter than the other portion 30b, and the space 29 is formed by being surrounded by the portion 29a, the protrusion 29b, and the dielectric 32. Is located. That is, in this configuration, the portion 30a near the tip of the inner conductor 30 protrudes toward the discharge space 12 but is located outside the space, and the protrusion is between the portion 30a and the outer conductor 31. By interposing 29b, the creepage distance is sufficiently secured, and the effect of preventing abnormal discharge between the conductors 30 and 31 is obtained.

  As the outer conductor 31, a member having a conductive film formed on the outer peripheral surface of a metal material or quartz glass is used. In this example, the end 31a of the outer conductor 31 formed into a cylindrical shape using a bulk material is bent inward, and as shown by a dimension “d” in the drawing, the end 31a is bent with respect to the end 31a. A tip portion of the inner conductor 30 protrudes toward the discharge tube 3F and is close to the discharge space 12.

  In addition, like the discharge lamp 33 shown in FIG. 8, the conductor 34 is provided as an auxiliary electrode at the tube wall position facing the tip of the internal conductor 30, and the conductor 34 is formed on a part 29c of the tube wall 29 of the discharge tube 3G. Luminous efficiency can be further improved by configuring the discharge space 12 so as to be buried. Or although illustration is abbreviate | omitted, the structure which located this conductor in the discharge space 12 in the state which the one end part of the conductor 34 was exposed similarly to the example shown in FIG.4 and FIG.5 may be sufficient.

  Next, structural examples using a transparent ceramic material for the discharge tube will be described with reference to FIGS.

  When the discharge tube is formed of a ceramic material, a method of sealing the end portion of the sealing extension (or the sealing leg) formed integrally with the discharge tube with low-melting glass is employed.

  FIG. 9 shows an example of the configuration of the discharge lamp having the above configuration (I), and an internal conductor protrudes into the discharge space.

  The discharge lamp 35 has a structure in which the discharge tube 3H is fixed to the waveguide 4C, and the waveguide 4C is connected to a power source (not shown) via a coaxial cable or the like.

  The discharge tube 3H includes a cylindrical tube 36 and a sealing portion 37 whose outer diameter is approximately the same as the outer diameter of the waveguide 4C.

  The sealing portion 37 is tapered at the end of the sealing extension portion 38 in a state where the conductive member 39 (rod-like conductor) is inserted into the sealing extension portion 38 having a smaller diameter than the cylindrical tube 36. It is formed by sealing the edge part (lower end part of a figure) with the low melting glass 40. FIG. Although a predetermined substance is sealed in the discharge space 41 in the cylindrical tube 36, the end 39 a (on the side opposite to the end sealed with the low melting point glass 40 of the conductive member 39 ( The portion near the tip is located in the discharge space 41.

  The conductive member 42 constitutes an internal conductor 43 together with the conductive member 39. In this example, a bulk material such as metal is used and a recess 42a is formed at one end thereof. The recess 42a receives the end of the sealing extension 38 (the portion sealed with the low-melting glass 40). In this state, the one end of the conductive member 39 and the end of the conductive member 42 are connected to each other. It is close. That is, the inner conductor 43 has the first conductive member 39 and the second conductive member 42, both members are separated, and a part of the sealing extension 38 is interposed between the two members. So that it is almost thermally insulated. And it has the structure which does not interfere with the propagation of the electromagnetic waves from the conductive member 42 to the conductive member 39 by arranging both members in close proximity.

  The outer conductor 44 constituting the waveguide 4C is coated on the outer peripheral surface of a tubular member 45 (outer tube) made of ceramic or quartz glass. That is, the conductive member 42 and the sealing extension 38 are positioned in the cavity of the tubular member 45, and the outer conductor 44 covered on the outer surface of the tubular member 45 is connected to the distal end portion of the member 45 and its end portion. It extends to the peripheral edge of the end face.

  A recess 45a is formed at the end of the tubular member 45, and the discharge tube 3H is formed at the end of the waveguide 4C in a state where the annular protrusion 46 formed in the discharge tube 3H is received in the recess 45a. Supported.

  The dimension “d” shown in the drawing indicates the distance between the tip of the conductive member 39 and the end of the external conductor 44, and a protrusion is provided between the conductive member 39 and the external conductor 44. By interposing 46 (dielectric material), a sufficient creeping distance can be secured, and an effect of preventing abnormal discharge between conductors can be obtained.

  FIG. 10 shows an example of the configuration of the discharge lamp having the above-described configuration (II). The inner conductor protrudes to a position close to the inner space of the discharge tube, and between the tip of the inner conductor and the outer conductor. There is a protrusion formed integrally with the discharge tube.

  The discharge lamp (electrodeless discharge lamp) 47 shown in this example is structurally different from the discharge lamp 35 shown in FIG. 9 as follows.

A ceramic rod-like member 48 is used instead of the conductive member 39. An inner conductor 49 is formed by applying a conductive coating to the outer peripheral surface of the sealing extension 38. The tip of the conductor protrudes to the vicinity of the discharge space 41. Another conductive member 50 constituting the inner conductor is not a bulk material, and a ceramic or quartz glass is used as a base material and a conductive coating is provided on the outer peripheral surface thereof. Being a given member.

  A step 52a is formed at the end of the tubular member 52 covered with the outer conductor 51, and the discharge tube 3I is guided in a state where the protrusion 46 formed on the discharge tube 3I is in contact with the step 52a. It is supported at the end of the tube 4D.

  In this example, a conductor 49 (conductive film) coated on the outer peripheral surface of the cylindrical sealing extension 38 constitutes an inner conductor, and the conductor 49 is an end of the sealing extension 38. It extends to the close part (small diameter part). And the said part is inserted by the recessed part 50a formed in the edge part of another electroconductive member 50 which comprises an internal conductor.

  A conductor 50 b (conductive film) is formed on the outer peripheral surface of the conductive member 50, and a part of the conductor 49 in which the conductor portion near the end is covered with the outer peripheral surface of the sealing extension 38. It is arranged close to. In other words, the inner conductor is composed of a plurality of separated conductors, so that the inner conductor is thermally insulated, and the end portions thereof are arranged close to each other, thereby hindering the propagation of electromagnetic waves. It is configured not to play.

  A ceramic rod-like member 48 is inserted into the sealing extension 38, and its end (the lower end in the figure) is sealed with the low melting point glass 40. Although a predetermined substance is sealed in the discharge tube 3I, the end 48a of the rod-shaped member 48 opposite to the end sealed with the low-melting glass 40 does not enter the discharge space 41. A function that regulates and prevents the material from accumulating by rejecting the entry of the encapsulated material at the time of extinction by narrowing the gap (clearance) formed between the rod-shaped member 48 and the sealing extension 38. Is given.

  The conductor 49 reaches the base of the sealing extension 38, and an annular protrusion 46 (or rib) is integrally formed in the vicinity thereof.

  A step 52a is formed at the end of the tubular member 52 covered with the outer conductor 51, and the protrusion 46 is in contact with the step 52a as shown in the dimension "d" in the drawing. The electromagnetic wave is introduced into the discharge space 41 in a state in which the front end portion of the inner conductor (the end portion of the conductor 49) protrudes toward the discharge space 41 than the end portion of the outer conductor 51.

  By providing a protrusion 46 made of the same material (dielectric material) as that of the discharge tube 3I between the conductor 49 and the conductor 51 and securing a sufficient creepage distance, an effect of preventing abnormal discharge between the conductors can be obtained. .

  In this example, the conductor 49 and the conductor 50b constituting the inner conductor are both formed as conductive films, and reducing the heat capacity contributes to the improvement of efficiency.

  In the above example, the end of the sealing extension 38 is inserted or engaged with the constituent member of the inner conductor. However, in the application of the present invention, the sealing extension is used. In various forms, such as bonding to the base material (dielectric) of the inner conductor with glass or adhesive, or forming a fastening portion such as a screw in the sealing extension and attaching it to the inner conductor or the base material Can be implemented. Alternatively, a screw portion of the discharge tube projection 46 is formed, and a screw groove corresponding to the screw portion is formed at the end portion of the tubular member 52, so that it is fastened by screwing, or an intermediate member such as a connector or a base. Alternatively, a form that is fixed by using an engaging member may be adopted (in consideration of replacement of the discharge tube, maintainability, etc., an attachment form in which the discharge tube can be easily attached or detached is preferable. ).

  Also, a discharge tube using a ceramic material can have a configuration in which another conductor is provided as an auxiliary electrode at a position facing the tip of the internal conductor in the tube wall.

  For example, like the discharge lamp 53 shown in FIG. 11, in the configuration example shown in FIG. 9, the conductor 54 is provided on the tube wall, and the end of the conductor is connected to the end 39 a of the conductive member 39 in the discharge space 41. What is necessary is just to make it confront, and by this, luminous efficiency can be raised further.

  According to the configuration described above, the following advantages can be obtained.

・ Improvement in luminous efficiency (for example, 110 lm / W or more) ・ Contributes to improvement in efficiency by projecting the inner conductor into the discharge tube and extending the inner conductor as a central conductor to the discharge space In addition, the arc position is fixed by maintaining the distance between the discharge arc and the tube wall, and there is no reduction in efficiency or shortening of the life that has been regarded as a problem in the past (FIGS. 2 to 6, FIG. 9, (See Fig. 11)
-By adopting a configuration in which the inner conductor is integrated with the discharge tube and the tip of the inner conductor protrudes into the discharge tube, electromagnetic waves can be introduced directly into the discharge tube, and the joule at the bottom of the discharge tube can be introduced. Loss (heat loss) can be reduced (see FIGS. 2 to 6, 9, and 11).
-By adopting a configuration in which the end of the inner conductor is close to the tube wall of the discharge tube, reaction between the conductor material and the enclosed substance in the discharge tube can be avoided, and the inner conductor can be placed against the discharge space. The electromagnetic wave can be efficiently introduced into the discharge tube by bringing them closer to each other (see FIGS. 7, 8, and 10).
・ If the internal conductor in the discharge tube is covered with the same material as the tube wall, the reaction between the conductive material and the encapsulated material in the discharge tube can be avoided, and the internal conductor is made as small as possible with respect to the discharge space. Electromagnetic waves can be efficiently introduced into the discharge tube by bringing them closer (see FIGS. 3, 5, and 6).
-The internal conductor is composed of a plurality of conductive members, the outer diameter of the conductive member located at the end of the waveguide is reduced, and heat insulation loss is reduced by insulating against other conductive members. (See FIGS. 2 to 6, 9, and 11)
-By adopting a configuration in which the outer conductor does not contact the discharge tube, loss due to heat conduction from the discharge tube to the outer conductor can be reduced (see FIGS. 2 to 6).
The configuration in which the auxiliary electrode is attached to the discharge tube (see FIGS. 4 to 6, 8, and 11) further increases the efficiency (provided that the coupling between the electromagnetic wave and the plasma is improved). It is necessary to consider the influence of light shielding by the auxiliary electrode.)
-By using the auxiliary electrode attached to the discharge tube as a starting electrode (see FIGS. 4 to 6, 8, and 11), a strong electric field can be applied to the discharge tube, and the discharge can be performed without using a Tessler coil or the like. The electric lamp can be easily started.-The discharge tube can be easily fixed and attached to the end portion of the waveguide, and the protrusion formed integrally with the discharge tube (FIGS. 7, 8, and 9 to 9). (See Fig. 11) Positioning can be performed using this and the protrusion is positioned between the outer conductor and the inner conductor, thereby preventing abnormal discharge between the conductors. By disposing in the waveguide, it becomes possible to have a structure in which no sealing portion is provided on the end surface of the discharge tube opposite to the end portion of the waveguide, and the light extraction efficiency is good (see FIGS. 2 to 11). .

  The present invention can be widely applied to various types of discharge lamps regardless of the shape of the discharge tube, the position and direction of arc formation, and the frequency of electromagnetic waves is not limited to the microwave band. Of course.

It is explanatory drawing which shows the basic structural example of the light source device which concerns on this invention. It is a figure which shows the cross-sectional structural example of the discharge lamp using quartz glass. It is a figure which shows another example of the cross-sectional structure of the discharge lamp using quartz glass. FIG. 3 is a diagram illustrating an example in which a conductor is provided at a position facing the internal conductor in the discharge space in the configuration of FIG. 2. FIG. 4 is a diagram showing an example in which a conductor is provided at a position facing the internal conductor in the discharge space in the configuration of FIG. 3. FIG. 4 is a diagram showing another example in which a conductor is provided at a position facing the internal conductor in the discharge space in the configuration of FIG. 3. It is a figure which shows another example about the cross-sectional structure of the discharge lamp using quartz glass. FIG. 8 is a diagram showing an example in which a conductor is provided at a position facing the internal conductor in the discharge space in the configuration of FIG. 7. It is a figure which shows the cross-sectional structural example of the discharge lamp using a ceramic material. It is a figure which shows another example of the cross-sectional structure of the discharge lamp using a ceramic material. FIG. 10 is a diagram illustrating an example in which a conductor is provided at a position facing the internal conductor in the discharge space in the configuration of FIG. 9.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Light source device, 2 ... Power supply part 3, 3A, 3B, 3C, 3D, 3E, 3F, 3G, 3H, 3I ... Discharge tube 4, 4A, 4B, 4C, 4D ... Waveguide, 4a ... External Conductor, 4b ... internal conductor, 5 ... tip, 8 ... discharge lamp, 11 ... conductive member, 12 ... discharge space, 13 ... internal conductor, 14 ... conductive member, 15 ... external conductor, 17 ... discharge lamp, 18 DESCRIPTION OF SYMBOLS ... Tube wall, 19 ... Discharge lamp, 20 ... Tube wall, 21 ... Conductor, 22 ... Discharge lamp, 23 ... Tube wall, 24 ... Conductor, 25 ... Discharge lamp, 26 ... Tube wall, 27 ... Conductor, 28 ... Discharge lamp 29 ... Tube wall, 29b ... Projection, 30 ... Inner conductor, 31 ... Outer conductor, 33 ... Discharge lamp, 34 ... Conductor, 35 ... Discharge lamp, 39 ... Conductive member, 41 ... Discharge space, 42 ... Conductivity Member, 43 ... Internal conductor, 44 ... External conductor, 46 ... Projection, 47 ... Discharge lamp, 49, 50b ... Internal conductor, 51 ... External conductor , 53 ... discharge lamp, 54 ... conductor

Claims (11)

In a discharge lamp using a discharge tube that emits light by plasma generated by receiving high-frequency electromagnetic waves, and a waveguide having an outer conductor and an inner conductor for transmitting the electromagnetic waves,
A tip portion of the inner conductor protrudes into the discharge space of the discharge tube, and the inner conductor is integrated with the first conductive member integrated with the discharge tube, and a first electrode provided in the waveguide. Composed of two conductive members,
The first conductive member and the second conductive member are arranged in close proximity to each other in a state where the discharge tube is attached to an end of the waveguide. Discharge lamp. In the discharge lamp according to claim 1,
A discharge lamp characterized by being positioned in the discharge space in a state in which a tip portion of the first conductive member is exposed. In the discharge lamp according to claim 1,
The discharge lamp according to claim 1, wherein a tip portion of the first conductive member is positioned in the discharge space in a state of being embedded in a tube wall of the discharge tube. In the discharge lamp according to claim 1, claim 2 or claim 3,
The discharge lamp according to claim 1, wherein an outer diameter of the first conductive member is smaller than an outer diameter of the second conductive member. In the discharge lamp according to claim 1, claim 2, claim 3 or claim 4,
The discharge lamp is characterized in that another conductor is attached to the tube wall of the discharge tube at a position facing the tip of the first conductive member. In the discharge lamp according to claim 5,
A discharge lamp characterized by being positioned in the discharge space in a state where one end portion of the another conductor is exposed or embedded in a tube wall of the discharge tube. In a discharge lamp using a discharge tube that emits light by plasma generated by receiving high-frequency electromagnetic waves, and a waveguide having an outer conductor and an inner conductor for transmitting the electromagnetic waves,
The tip of the inner conductor protrudes to a position close to the discharge space or tube wall of the discharge tube, and a protrusion formed integrally with the discharge tube between the tip and the outer conductor A discharge lamp characterized by interposing. In the discharge lamp according to claim 7,
A discharge lamp characterized in that another conductor is attached to the tube wall of the discharge tube at a position facing the tip of the internal conductor. The discharge lamp according to claim 8,
A discharge lamp characterized by being positioned in the discharge space in a state where one end portion of the another conductor is exposed or embedded in a tube wall of the discharge tube. In a light source device including a power source for generating electromagnetic waves, a discharge tube that discharges and emits light by plasma generated by receiving high-frequency electromagnetic waves from the power source, and a waveguide for transmitting electromagnetic waves to the discharge tube,
The light guide device, wherein the waveguide has an outer conductor and an inner conductor, and a tip portion of the inner conductor protrudes into a discharge space of the discharge tube. In a light source device including a power source for generating electromagnetic waves, a discharge tube that discharges and emits light by plasma generated by receiving high-frequency electromagnetic waves from the power source, and a waveguide for transmitting electromagnetic waves to the discharge tube,
The waveguide has an outer conductor and an inner conductor, and the tip of the inner conductor protrudes to a position close to the discharge space or the tube wall of the discharge tube, and between the tip and the outer conductor. In the light source device, a projection formed integrally with the discharge tube is interposed.

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