JP2011238379A - Ceramic metal halide lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To light a ceramic metal-halide lamp while stabilizing arc from initial stage of lighting even if cerium iodide is added to an arc tube as a metal halide.SOLUTION: An arc tube (1) where a light-emitting part (2) and capillaries (3A, 3B) to which a pair of electrode assemblies (6A, 6B) arranged at the opposite ends thereof is inserted are formed of translucent ceramic is contained in a translucent outer tube (10), and cerium iodide is added as a metal halide. In such a ceramic metal-halide lamp (L), a closed-loop arc tube supporting frame (F) equipped with two parallel posts (12R, 12L) extending in the longitudinal direction from the proximal end (10A) side where a base (11) is formed to the distal end (10B) side is fixed by welding to a stem lead (18b) receiving power supply through the base (11), in the outer tube (10). At least a part of one parallel post corresponding to the position of the light-emitting part (2) of the arc tube (1) is constituted of a non-conductive member (23).

Description

  The present invention relates to a ceramic metal halide lamp to which cerium iodide is added as a metal halide.

The metal halide lamp emits light that is closest to natural light compared to a high-pressure sodium lamp or a mercury lamp, and therefore has excellent color rendering properties, and is also used as a base lighting in offices and stores.
In general, a light source having an average color rendering index Ra of 80 or more in ISO 8995 color rendering category 1B or higher and a correlated color temperature in the range of 3000 to 4500 K and a range from warm to white is used. From the viewpoint of energy saving, a lamp with higher luminous efficiency is demanded.
However, high color rendering and high efficiency are contradictory effects. If the color rendering is improved, the luminous efficiency is lowered, and if the luminous efficiency is increased, the color rendering is lowered.
For this reason, the conventional metal halide lamps are classified into either an efficiency-oriented type or a color rendering property-oriented type even if high efficiency and high color rendering are desired.
In this case, generally, if the average color rendering index Ra ≧ 80, it is evaluated as high color rendering (ISO 8995 color rendering category 1B or higher), and if the luminous efficiency η ≧ 100, it is evaluated as high efficiency.

  For example, the highest data of the Dy-Ho-Tm metal halide lamp disclosed in Patent Document 1 is excellent with an average color rendering index Ra = 87, but is slightly inferior with luminous efficiency η = 93 (lm / W). It can be said that it is an important type.

  The Na—Ce-based metal halide lamp disclosed in Patent Document 2 is excellent with an average luminous efficiency η = 123 (lm / W) due to intense green light emission of Ce, but is slightly inferior with an average color rendering index Ra = 60. It can be said that it is an efficiency-oriented type (see Patent Document 2 [0049]).

  Further, Patent Document 2 [0082] states that “in addition to NaI, dysprosium (Dy), thulium (Tm), holmium (Ho), thallium (Tl), etc. are appropriately used depending on the desired lamp characteristics. However, even if these substances are added to adjust the ratio of the luminescent encapsulating substance of the Na—Ce metal halide lamp, the intense green light emission of Ce is suppressed and Ra = Not only is it difficult to make it 70 or more, but when Dy, Tm, Ho, and Tl are added as light emitting substances, the lamp characteristics of Patent Document 1 are approached and the light emission efficiency is lowered.

  On the other hand, conventional high color rendering ceramic metal halide lamps achieve high color rendering and high luminous efficiency by increasing the heat insulation effect of the arc tube by evacuating the translucent outer tube that houses the arc tube. Since the arc tube is difficult to be cooled when the lamp is turned off, it takes about 25 to 30 minutes to restart the lamp after it is turned off, and it is desired to reduce this to about 15 minutes.

Although it is possible to shorten the restart time by increasing the starting pulse voltage, when a pulse voltage that can be restarted within 15 minutes was measured in a prototype lamp with a vacuum inside the translucent outer tube, a high voltage pulse of 3 kV or higher I found that it was necessary.
In the recent usage environment that emphasizes safety and security, it is considered that a starting voltage of about 1 to 1.5 kV is appropriate. In a general lighting lamp of a low starting voltage type that is lit by a mercury lamp ballast, it is desirable to avoid generating a high voltage pulse of 3 kV in terms of safety.

  Therefore, the present inventor has achieved both high color rendering and high efficiency, which are contradictory effects in a metal halide lamp, and specifically, the luminous efficiency η ≧ while maintaining the high color rendering of an average color rendering index Ra ≧ 80. A lamp has been developed that achieves a high efficiency of 100 (lm / W) and shortens the restart time with a starting pulse voltage comparable to that of a conventional lamp (see Japanese Patent Application No. 2009-148358).

As shown in FIG. 3, the lamp 20 has a light emitting part 2 in which a metal halide, mercury and a starting rare gas are sealed, and capillaries 3A and 3B arranged at both ends thereof, which are formed of a translucent ceramic. The tube 1 is accommodated in the translucent outer tube 10.
The inner diameter of the arc tube is substantially constant in the capillaries 3A and 3B, but the diameter increases in the center of the light emitting portion. In this way, the position where the inner diameter of the arc tube starts to expand is defined as the boundary between the light emitting portion 2 and the capillary 3A or 3B.
A pair of electrode assemblies 6A and 6B including electrodes 5A and 5B are inserted into capillaries 3A and 3B formed at both ends of the light emitting unit 2, and are hermetically sealed.
In the outer tube 10, two parallel struts 12 </ b> R and 12 </ b> L extending along the longitudinal direction from the base end 10 </ b> A side of the outer tube 10 in which the base 11 is formed to both sides of the arc tube 1 to the tip 10 </ b> B side. A closed loop type power feeding and combined arc tube support frame 21 in which a positioning fitting 13 is welded is disposed at the tip of the tube.

This support frame 21 is a ring that prevents the displacement of the support frame 21 by being abutted on the inner surface of the outer tube tip 10B on the tip side of two parallel columns 12R, 12L formed by bending both ends to the outer tube tip side. 3 is welded to form a square closed loop when viewed from the direction of FIG. 3, and the arc tube 1 is supported via a pair of support disks 16A and 16B.
Since the support frame 21 is formed in a closed loop type, it has high rigidity and is difficult to be deformed even when an external force is applied. When the support frame 21 vibrates due to an external force acting on the lamp 20 during transportation, the support frame 21 is deformed. As a result, the arc tube 1 is not displaced, and the weakly formed capillaries 3A and 3B formed at both ends thereof are not damaged.
In particular, in a lamp with a built-in starter, circuit components are attached to the support frame 21. Therefore, if the support frame 21 has high rigidity, the start circuit is less likely to be destroyed due to the influence of vibration or the like.

  The stem 14 formed inside the base 11 is provided with a pair of stem leads 18A and 18B that receive power supply via the base 14, and one electrode protruding from the capillary 3A of the arc tube 1 is provided. The lead 7A is connected to one stem lead 18A, and the other electrode lead 7B is supplied with power through a metal lead 22 attached to the distal end side of the support frame 21 welded to the other stem lead 18B. ing.

  That is, the support frame 21 that is a conductor extends from the base end 10A side of the outer tube 10 on which the base 10 is formed to the front end 10B side where the electrode lead 7B of the arc tube 1 is disposed. It has been conventional technical common sense to use as a member.

The arc tube contains at least thulium iodide, thallium iodide, sodium iodide and calcium iodide as the metal halide, and sodium iodide and calcium iodide are contained in the total metal halide. Each is encapsulated in a molar ratio of 40-80% and less than 30%.
If necessary, for example, when improving the luminous efficiency, cerium iodide is enclosed in a molar ratio of 5% or less with respect to the total metal halide.

  When cerium iodide is added to this lamp 20, if it is lit stably, it becomes a lamp with excellent color rendering properties and luminous efficiency. However, when it is lit vertically, the arc is stabilized for several tens of hours at the beginning of lighting. In other words, it has been found that the arc may be bent, the arc voltage may be changed, or the lamp voltage may be greatly changed to change the emission color or cause the lamp to disappear. This is a unique phenomenon seen with lamps containing cerium.

That is, since power is supplied to the electrode 5B on the distal end side of the arc tube 1 via the metal lead 22 connected to the distal end side of the closed loop type support frame 21, two wires are provided from the stem lead 18B standing on the stem 14. Two power supply routes reaching the metal lead 22 through the parallel columns 12R and 12L are formed.
Therefore, to start the power supply, for example, as shown in FIG. 4, the parallel struts 12R, a current flows in the arrow _{A 1} direction 12L, the magnetic field _B 1, _{B 2} are formed, the magnetic field _B 1, _{B 2} The light emitting part 2 is located inside.

Since the electrode 5A, the arc between 5B current flows in the arrow _{A 2} direction, relative to an arc, each of the parallel struts 12R by Fleming's left hand rule, force _W 1 in a direction away from the 12L, _{W 2} acts.
That is, at this time, since the two magnetic fields B ₁ and B _{2 in the} opposite directions are acting at the intermediate portions of the parallel struts 12R and 12L, the two forces W ₁ and W _{2 in the} opposite directions are also applied to the arc. Act simultaneously.
Then, the polarity is inverted by an alternating current, the parallel struts 12R, current flows in opposite to the arrow _{A 1} direction 12L, electrodes 5A, even when the current flows in opposite to the arrow _{A 2} direction between 5B, parallel struts 12R, the 12L A similar phenomenon occurs because two magnetic fields in exactly opposite directions are generated in the middle part, and a force acts on the arc in a direction away from the respective parallel struts 12R and 12L.
Therefore, since the arc is pushed from both sides, there is no place to go in the direction of the force (left-right direction as viewed in FIG. 4), and the direction perpendicular to this (the direction toward the front or back of the page as viewed in FIG. 4). ) Turns into an unstable state.
Moreover, in the case of containing cerium, the arc discharge route is not stable because the excess additive present in the arc tube does not evaporate evenly at the beginning of lighting. Thus, it is considered that the arc oscillates by repeating the arcs coming and going due to the delicate balance of the force.

JP 2003-187744 A JP 2003-086130 A

  Therefore, the present invention has a technical problem to make it possible to stabilize the arc from the beginning of lighting even when cerium iodide is added to the arc tube when a closed-loop support frame is formed.

  In order to solve this problem, the present invention is a translucent ceramic comprising a light emitting part enclosing a metal halide, mercury and a starting rare gas, and capillaries through which a pair of electrode assemblies arranged at both ends thereof are inserted. In the ceramic metal halide lamp in which the formed arc tube is housed in the translucent outer tube and at least cerium iodide is added as the metal halide, the arc tube is formed from the base end side where the cap of the outer tube is formed. A closed-loop arc tube support frame with two parallel struts extending along the longitudinal direction through both sides of the tube to the tip side is welded and fixed to the stem lead that receives power supply through the base, and is arranged in the outer tube. And one of the parallel struts is characterized in that at least a portion corresponding to the position of the light emitting portion of the arc tube is made of a non-conductive member. To have.

According to the ceramic metal halide lamp of the present invention, when a closed loop type support frame that supports the arc tube is disposed, a part of the support frame is used as a non-conductive member.
Thereby, since a current flows through only one of the two parallel columns positioned on both sides of the arc tube, a magnetic field in the opposite direction is not formed between the parallel columns.
A magnetic field is formed around the parallel columns that are energized, but only one direction of the magnetic field is formed in the part where the arc is formed, so that the arc becomes unstable even under the influence of the magnetic field. Less is.
Since the support frame is formed in a closed loop type, it is difficult to deform even when an external force is applied. When supporting a weakly formed capillary formed at both ends of the arc tube, the external force acts on the lamp during transportation. The arc tube will not be displaced or damaged due to deformation of the frame when it vibrates.
Further, in the starter built-in type lamp, the starter circuit component attached to the closed loop type support frame is not destroyed by the deformation of the frame.

Explanatory drawing which shows an example of the ceramic metal halide lamp which concerns on this invention. The figure which shows the force which acts on an arc at the time of the electricity supply. Explanatory drawing which shows the conventional ceramic metal halide lamp. The figure which shows the force which acts on an arc at the time of the electricity supply.

  Even if cerium iodide is added to the arc tube, in order to achieve the purpose of stabilizing the arc from the beginning of lighting, a light emitting portion in which metal halide, mercury and a starting rare gas are sealed, and both ends thereof A ceramic metal halide lamp in which a light-emitting tube formed of a translucent ceramic with a capillary inserted through a pair of electrode assemblies is housed in a translucent outer tube and cerium iodide is added as the metal halide A closed-loop arc tube support frame having two parallel struts extending along the longitudinal direction from the base end side of the outer tube on which the base is formed to both sides of the arc tube to the distal end side is provided via the base. One of the parallel struts is attached at least to the position of the light emitting portion of the arc tube. Portion is configured to be a non-conductive member.

A ceramic metal halide lamp L shown in FIG. 1 includes a luminous tube 1 and a non-linear ceramic capacitor for supplying a starting voltage between its electrodes 5A and 5B in a translucent outer tube 10 having a base 11 formed at one end. A vessel 9 is arranged.
The arc tube 1 has a transition curved surface in which a pair of capillaries 3A and 3B have no corners at both ends in the major axis direction of the light emitting unit 2 formed in a substantially elliptical shape that is rotated about the major axis of the ellipse. 4, the light emitting section 2 is filled with a metal halide, mercury, and a starting rare gas.
The inner diameter of the arc tube is substantially constant in the capillaries 3A and 3B, but the diameter increases in the center of the light emitting portion. In this way, the position where the inner diameter of the arc tube starts to expand is defined as the boundary between the light emitting portion 2 and the capillary 3A or 3B.

The arc tube 1 of this example uses a so-called one-piece type in which the light emitting part 2 and the capillaries 3A and 3B are integrally molded by molding a powdered compact of translucent alumina.
A pair of electrode assemblies 6A and 6B having electrodes 5A and 5B are inserted into the capillaries 3A and 3B formed at both ends of the light emitting unit 2, and both ends of the capillaries 3A and 3B are electrically insulated frit. At the same time as being hermetically sealed by a sealing material such as glass, the electrode assemblies 6A and 6B are fixed at fixed positions in the capillaries 3A and 3B by the sealing material.

Note that the light emitting portion 2, a metal halide, at least iodide thulium _(TmI 3), thallium iodide (TlI), along with sodium iodide (NaI) and calcium iodide (CaI ₂₎ is enclosed, iodine Sodium iodide (NaI) and calcium iodide (CaI ₂ ) are encapsulated in molar ratios of 40-80% and less than 30%, respectively, with respect to the total metal halide.
Further, cerium iodide (CeI ₃ ) is enclosed in a molar ratio of 5% or less with respect to the total metal halide.

Further, in the outer tube 10, a closed-loop type light emission provided with two parallel columns 12 R and 12 L extending along the longitudinal direction from the base end 10 A side to the tip end 10 B side of the outer tube 10 in which the base 11 is formed. A tube support frame F is arranged.
This support frame F is formed with two parallel struts 12R, 12L having the same length by bending both ends of the metal linear member 12 toward the tip 10B side of the outer tube 10, and at the tip thereof, the outer tube tip A ring-shaped positioning fitting 13 that is brought into contact with the inner surface of 10B and prevents the position of the frame tip from being displaced is welded to form a square closed-loop type as viewed in FIG.

  However, of the two parallel struts, a part of the parallel strut 12R is made of a non-conductive ceramic rod. The ceramic rod is preferably slightly longer than the range in contact with the parallel struts 12R when the position of the light emitting unit 2 is expanded in the outer peripheral direction. That is, there is only one conductive line that functions as a power supply line in the space where the light emitting portion position is extended in the outer peripheral direction. In principle, if the range corresponding to the position where the arc is generated when the arc tube 1 is lit is replaced with the ceramic rod, the effect of the present invention can be obtained. In consideration, at least the range corresponding to the light emitting portion 2 is replaced with a ceramic rod, so that the effect of the present invention is reliably exhibited. The connection between the conductive portion and the non-conductive portion of the parallel strut 12R is performed by, for example, fixing the metal cap to the ceramic rod that is the non-conductive portion and fixing the metal cap and the parallel strut in the same manner as the lead wire connecting method at both ends of the carbon resistor. What is necessary is just to connect the metal wire which is a 12R electroconductive part by butt welding.

  A pair of support disks 16A and 16B are attached to the two parallel struts 12R and 12L, and the capillaries 3A and 3B are inserted into insertion holes (not shown) formed at the centers thereof, so that the arc tube 1 is installed. The translucent sleeve 17 is fixed to the discs 16 </ b> A and 16 </ b> B so as to surround the light emitting unit 2.

The stem 14 formed inside the base 11 is provided with a pair of stem leads 18A and 18B that receive power supply via the base 14, and one electrode protruding from the capillary 3A of the arc tube 1 is provided. The lead 7A is connected to one stem lead 18A. The other electrode lead 7B is fed with power from the base 11 side of the support frame F welded to the other stem lead 18B through only the parallel strut 12L and through the metal lead 22 attached to the front end side of the support frame F. It is like that.
Further, the starter 9 is electrically connected between the power supply leads 7A and 7B.

The above is one configuration example of the present invention, and the operation thereof will be described next.
When the base 11 of the ceramic metal halide lamp L is mounted on a lamp socket (not shown) and a switch (not shown) is turned on, a lamp current flows between the electrodes 5A and 5B and the lamp is turned on.
At this time, since the non-conductive member 23 is provided in the vicinity of the light emitting portion 2 of the parallel support 12R, the current does not flow or is not affected by the magnetic field.

Therefore, as shown in FIG. 2, there is only one parallel column 12L as an element that forms a magnetic field between the electrodes 5A and 5B where the arc is formed, and the parallel column 12L has, for example, an arrow A _1. When the lamp current is supplied in the direction, a magnetic field B is formed around the parallel support 12L.
Electrodes 5A, since it is formed arc is between 5B, will flow a current in the opposite arrow A ₂ direction to the current flowing through the power supply wire 8 in a magnetic field B, and the arc, Fleming left hand A force W in a direction away from the parallel strut 12L works according to the law.

Further, when the lamp current to the parallel strut 12L for example, opposite to the arrow A ₁ direction is supplied, although the magnetic field B around the feed wire 8 magnetic field opposite is formed, the electrodes 5A, the arc between 5B Once generated, the electrodes 5A, will flow a current in opposite to the arrow a ₂ direction opposite to the current flowing through the parallel strut 12L is between 5B, for the arc, from the parallel strut 12L by Fleming's left-hand rule The force W in the direction of leaving works.

  That is, no matter which direction the lamp current flows, only the force W in the same direction away from the parallel support 12L acts on the arc, and the force in the opposite direction (direction approaching the parallel support 12L) acts simultaneously. Therefore, the arc does not act in an alternating manner by an alternating lamp current and is not pulled sequentially in a plurality of directions.

  As described above, the present invention can be applied to the use of a ceramic metal halide lamp used as base lighting in an office or a store.

L ... Ceramic metal halide lamp 1 ... Arc tube
2 ... Light emitting part
3A, 3B ......... Capillary 5A, 5B ......... Electrodes
6A, 6B ......... Electrode assembly 10 ......... Outer tube 11 ......... Base 10A ......... Base end 10B ......... Tip 12R, 12L ......... Parallel column F ......... Support frame

Claims (2)

An arc tube formed of a translucent ceramic with a light emitting part enclosing a metal halide, mercury, and a rare gas for starting, and a capillary inserted through a pair of electrode assemblies arranged at both ends of the light emitting part is provided in the translucent outer tube. In a ceramic metal halide lamp that is housed and to which at least cerium iodide is added as the metal halide,
A closed-loop arc tube support frame having two parallel struts extending along the longitudinal direction from the base end side where the cap of the outer tube is formed to both sides of the arc tube to the distal end side is provided via the cap. At least one portion of the parallel struts corresponding to the position of the light emitting portion of the arc tube is made of a non-conductive member. A ceramic metal halide lamp characterized by   2. The ceramic metal halide lamp according to claim 1, wherein the arc tube has the capillaries continuously formed through transition curved surfaces having no corners at both ends in the major axis direction of the light emitting portion formed in a substantially elliptical shape. .

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