JP4258320B2 - Electrodeless discharge lamp device - Google Patents

Description

  The present invention relates to a lighting device for an electrodeless discharge lamp that is lit by passing a high-frequency current through an induction coil without having an external electrode.

  Conventionally, electrodeless discharge lamp devices are known. Since the electrodeless discharge lamp does not have an external electrode, it has an advantage of a long life compared to general discharge or the like. As shown in FIG. 3, the electrodeless discharge lamp device includes a discharge lamp 51 having a phosphor layer provided on the inner surface and enclosing mercury vapor as a discharge gas and a rare gas therein, and electromagnetic energy in the discharge lamp 51. And a lighting circuit 53 for supplying a high frequency current to the induction coil 52. When a high-frequency current is passed through the induction coil 52, a high-frequency electromagnetic field is generated inside the discharge lamp 51, and the discharge gas is excited to generate ultraviolet rays, which are converted into visible light by the action of the phosphor. To do.

  However, when the outside air temperature is extremely low, the vapor pressure of mercury decreases, and the light output may decrease.

  By improving this electrodeless discharge lamp device, by adding a high-frequency electromagnetic field to the generating induction coil and providing a heating coil that directly heats the metal member, the temperature of the discharge lamp is increased, so that The structure which suppresses the fall of the optical output of this is disclosed by Unexamined-Japanese-Patent No. 6-5006 (patent document 1). However, in this configuration, since the induction coil and the heating coil are operated simultaneously, the efficiency of the lighting circuit may be reduced.

Further, in Japanese Utility Model Publication No. 9-320523 (Patent Document 2), as shown in FIG. A configuration in which an amalgam 60 is placed in 51 thin tubes 58 and an induction coil 52 is wound around the outer periphery of the thin tube 58 is disclosed. By doing so, the amalgam 60 is heated by receiving the energy of the induction coil 52, and the vapor pressure of mercury is suppressed from decreasing, and the light output can be prevented from decreasing. However, in this configuration, it is necessary for the induction coil 52 to supply energy for generating a high-frequency electromagnetic field and energy for heating the amalgam 60, and the efficiency may also decrease.
Japanese Utility Model Publication No. 6-5006 Japanese Utility Model Publication No. 9-320523

  The present invention has been invented in view of the above-mentioned background art, and an object thereof is to provide a highly efficient electrodeless discharge lamp device in which the light output does not decrease even when the surroundings are at a low temperature.

In order to solve the above problems, an electrodeless discharge lamp device according to the present invention comprises a discharge lamp having a phosphor layer provided on the inner surface thereof and an amalgam, an induction coil for supplying electromagnetic energy to the discharge lamp, An electrodeless discharge lamp device comprising a lighting circuit for supplying a high-frequency current to the induction coil, comprising a temperature detection unit for detecting the temperature of the discharge lamp, wherein the discharge lamp is substantially a light bulb An outer pipe valve having a shape, and an exhaust pipe that is connected to a hollow portion provided in the outer pipe valve to internally provide the amalgam, and the induction coil is wound around an outer peripheral portion of the exhaust pipe. , a low temperature during the induction coil is energized at a low temperature of the discharge lamp, and a high temperature during the induction coil is energized at a high temperature of the discharge lamp, the inductance value of the low temperature induction coil and the high temperature during the induction coil The conductance value is substantially equal, and the temperature detection unit indirectly detects the temperature of the discharge lamp. When the discharge lamp is lit, the low temperature induction coil or the high temperature induction coil It is characterized in that only one of them is energized .

  In the electrodeless discharge lamp device of the present invention, the induction coil has a low temperature induction coil that is energized at a low temperature of the discharge lamp and a high temperature induction coil that is energized at a high temperature of the discharge lamp, Even when the ambient temperature is low, by using an induction coil at low temperature, it is possible to efficiently heat the amalgam and maintain the mercury vapor pressure at a certain level or more without causing a decrease in light output. . Moreover, since it has a temperature detection part, it can discharge efficiently according to the temperature of a discharge lamp.

  By doing so, it is possible to provide an electrodeless discharge lamp device that can be lit with a relatively low-cost lighting circuit, and in which the light output does not decrease even when the ambient temperature is low. it can.

1 and 2 show an electrodeless discharge lamp device which is an embodiment corresponding to claim 1 of the present application. FIG. 1 is a cross-sectional view of a discharge lamp 1 according to this embodiment. The outer shape of this is composed of a substantially bulb-shaped outer tube bulb 2 and an exhaust pipe 5 connected to the outer tube valve 2 by a hollow portion 6 provided inside the outer tube bulb 2. The outer pipe valve 2 and the exhaust pipe 5 are usually made of glass. A phosphor layer 3 and a protective film 4 are applied to the peripheral wall of the outer tube bulb 2. Here, examples of the sintered material of the phosphor material include Al ₂ O ₃ , Y ₂ O ₃ , and MgO. By increasing the addition amount of these sintering materials, it is possible to protect the phosphor and prevent deterioration. The discharge lamp 1 is filled with mercury as a discharge gas and a rare gas such as argon or krypton. Furthermore, inside the exhaust pipe 5, an amalgam 7 for controlling the vapor pressure of mercury and a glass rod 10 for fixing the position thereof are placed. The exhaust pipe 5 is also provided with a recess 11 so that the amalgam 7 does not move to the outer pipe valve 2 side.

  A low temperature induction coil 9 and a high temperature induction coil 8 are wound around the outer periphery of the exhaust pipe 5 in the hollow portion 6. As shown in FIG. 2, these induction coils are made by winding copper wire, and the low temperature induction coil 9 is disposed in the vicinity of the amalgam 7 and on the glass rod 10 side of the concave portion 11. The hour induction coil 8 is disposed on the outer tube valve 2 side of the recess 11. Here, by setting the number of turns and the diameter of each of the low temperature induction coil 9 and the high temperature induction coil 8 to be substantially the same, the inductance values of both coils are made to be substantially the same value. Further, if necessary, a high-frequency soft magnetic material such as ferrite is provided between the winding of each coil and the exhaust pipe 5 (not shown) to generate a high-frequency electromagnetic field generated when the coil is energized. Can be increased, and the frequency can be reduced. Further, a temperature detector 13 is provided outside the exhaust pipe 5 and on the opposite side of the outer pipe valve 2. The temperature detector 13 detects the temperature of the discharge lamp 1 at each winding position by measuring the electrical resistance of the low temperature induction coil 9 and the high temperature induction coil 8. In addition, a base 12 is provided for fixing the low temperature induction coil 9, the high temperature induction coil 8, the temperature detection unit 13, and the like to the discharge lamp 1.

  In the electrodeless discharge lamp apparatus, a low temperature induction coil 9 and a high temperature induction coil 8 disposed on the outer periphery of the exhaust pipe 5 of the discharge lamp 1 are connected to a lighting circuit 14. Here, the induction coil 9 at low temperature and the induction coil 8 at high temperature are connected to the lighting circuit 14 in parallel, and the discharge lamp 1 of each coil portion measured by the temperature detector 13 is used. The energization is switched. First, when the discharge lamp 1 is at a temperature higher than normal, that is, when the vapor pressure of mercury inside is higher than a predetermined value, a high-frequency current is passed through only the high-temperature induction coil 8. The frequency of the high-frequency current is several MHz to several tens of MHz in the case of a structure without high-frequency soft magnetic material (so-called air-core coil structure), and several tens of kHz to several hundred kHz in the case of a structure with high-frequency soft magnetic material. is there. Here, a high-frequency electromagnetic field is generated by the induction coil 8 at a high temperature, and the discharge gas inside the discharge lamp 1 collides with electrons to be in an ionized state, and discharge is generated. The discharged discharge gas once enters an excited state and then emits ultraviolet rays to return to the ground state. When this ultraviolet light hits the phosphor material, it is converted into visible light, and visible light is emitted.

  Next, when the discharge lamp 1 has a low temperature, this is detected by the temperature detector 13. Then, a high-frequency current is applied only to the low temperature induction coil 9. Since the low temperature induction coil 9 is wound in the vicinity of the amalgam 7, an eddy current is generated inside the amalgam 7 by the high frequency magnetic field generated by this coil, and the temperature rises due to self-heating. As a result, mercury vapor is generated from the amalgam 7 and the temperature of the discharge lamp 1 rises. This is detected by the temperature detector 13, and when the temperature of the high temperature induction coil 8 reaches a predetermined value, the coil that conducts the high-frequency current is switched from the low temperature induction coil 9 to the high temperature induction coil 8. By doing so, the vapor pressure of mercury, which is a discharge gas, is increased, and visible light is emitted without lowering the light output. Further, when the temperature of the induction coil 9 at low temperature decreases due to dimming or a change in external temperature, the coil for supplying a high-frequency current is switched to the induction coil 9 at low temperature to heat the amalgam 7. By doing so, the temperature of the discharge lamp 1 is raised to suppress a decrease in mercury vapor pressure, thereby preventing a decrease in light output.

  As described above, in the electrodeless discharge lamp apparatus according to the present embodiment, when the temperature of the discharge lamp becomes low, the coil for applying a high-frequency current is switched from the high temperature induction coil to the low temperature induction coil. By doing so, the amalgam is heated by self-heating to raise the temperature of the discharge lamp. As a result, even if the temperature of the discharge lamp decreases due to dimming or a change in external temperature, it can be immediately increased to the original temperature, and a decrease in light output can be prevented.

  In addition, the inductance value of the low temperature induction coil and that of the high temperature induction coil are substantially equal, and when the discharge lamp is turned on, only the low temperature induction coil or the high temperature induction coil is energized. Even when the coil is energized, the output voltage and current from the lighting circuit are constant. Therefore, it is not necessary to control the output of the lighting circuit, the circuit configuration is not complicated more than necessary, and the cost can be reduced.

  Furthermore, since the temperature detection unit indirectly detects the temperature of the discharge lamp that detects the temperature by measuring the coil resistance value, it is necessary to separately attach a temperature sensor such as a thermocouple. Instead, the temperature can be detected simply by adding a current / voltage detection circuit to a normal lighting circuit.

It is sectional drawing of the discharge lamp which concerns on this invention. It is a perspective view of the induction coil of this invention. It is a block diagram of the conventional electrodeless discharge apparatus. It is sectional drawing of the discharge lamp of another conventional electrodeless discharge apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge lamp 2 Outer tube bulb 3 Phosphor layer 4 Protective film 5 Exhaust tube 6 Hollow part 7 Amalgam 8 High temperature induction coil 9 Low temperature induction coil 10 Glass rod 11 Recess 12 Base 13 Temperature detection part 14 Lighting circuit

Claims (1)

A discharge lamp provided with a phosphor layer on the inner surface and provided with an amalgam, an induction coil for supplying electromagnetic energy to the discharge lamp, and a lighting circuit for supplying a high-frequency current to the induction coil. An electrode discharge lamp device,
A temperature detection unit for detecting the temperature of the discharge lamp;
The discharge lamp has a substantially bulb-shaped outer tube bulb, and an exhaust tube that is connected to a hollow portion provided in the outer tube bulb and internally places the amalgam,
The induction coil is wound around the outer periphery of the exhaust pipe, and has a low temperature induction coil that is energized at a low temperature of the discharge lamp, and a high temperature induction coil that is energized at a high temperature of the discharge lamp ,
The inductance value of the induction coil at low temperature and the inductance value of the induction coil at high temperature are substantially equal,
The temperature detection unit indirectly detects the temperature of the discharge lamp,
When the discharge lamp is turned on, only one of the low temperature induction coil and the high temperature induction coil is energized.

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