JPH0646599B2 - Electrodeless discharge lamp device - Google Patents

Description

Description: TECHNICAL FIELD The present invention applies a high-frequency electromagnetic field to a valve in which a rare gas or a rare gas and a metal vapor are sealed to discharge a gas body inside the valve and emit light accompanying the discharge. Alternatively, the present invention relates to a so-called electrodeless discharge lamp device in which ultraviolet rays generated by this discharge are converted into visible light by a fluorescent body and used.

(Background Art) An incandescent light bulb that is currently widely used as a light source for illumination has low efficiency and has a shortcoming that it has a short life. An electrodeless discharge lamp is one of the lamps that can eliminate the drawbacks and can replace the incandescent light bulb that is a small light source.

Since electrodeless discharge lamps do not require electrodes, they have a long life and are efficient, and have been studied in various places. FIG. 1 shows an example of such a conventional electrodeless discharge lamp, which has a structure in which a fluorescent material 1 is applied to an inner wall surface and a metal vapor such as mercury and an inert gas such as argon are applied inside. Enclosed valve 2
And an induction coil 3 wound around the outer periphery of the valve 2, a high frequency oscillator 4 for applying a high frequency to the induction coil 3 and a power source 5, and a high frequency generated by the high frequency oscillator 4 is applied to the induction coil 3. Ultraviolet rays emitted by ionizing the metal vapor such as mercury in the bulb 2 by the fluorescent material 1 applied to the inner wall surface of the bulb 2 become visible light and are emitted from the bulb 2.

However, when a saturated vapor pressure type lamp such as a general fluorescent lamp is used as the lamp, the light output changes depending on the tube wall temperature, and the light output at a low temperature of 0 ° C or lower is extremely lower than that at room temperature. It is well known that the starting characteristic is deteriorated and the lamp is difficult to light at low temperature. This characteristic is the same as in the above electrodeless discharge lamp, and the lamp 8 does not light at low temperature. However, there is a big problem that the light output is extremely lower than that at room temperature even when it is turned on, and it takes time to obtain a stable light output.

In order to improve such problems, a method of preheating the coldest part of the lamp with a heater or the like is known (for example,
(See Japanese Patent Publication No. 4-6544 and Japanese Patent Publication No. 37-6045). However, in such a conventional example, in order to prevent electric noise from leaking from the heater circuit, an extra filter circuit and the like must be provided, and there is still a problem.

(Object of the Invention) The present invention has been made in view of the above problems, and an object of the present invention is to suppress the reduction of the light output at the time of cold start, and to provide a uniform light output without being largely affected by the ambient temperature. It is to provide an electrodeless discharge lamp device to be obtained.

(Disclosure of the Invention) Hereinafter, the present invention will be described based on Examples. FIG. 2 shows an embodiment of the present invention. The structure different from the conventional example shown in FIG. 1 is such that an auxiliary coil 6 for low temperature is wound around a part of the valve 2 and the auxiliary coil 6 is used. Is connected via the changeover switch 7 in parallel with the induction coil 3 connected to the high frequency oscillator 4.

Here, the changeover switch 7 is turned on until the lamp 8 is turned on.
Is set to the auxiliary coil 6 side, the high frequency output of the high frequency oscillator 4 is transmitted to the auxiliary coil 6. And
When the lamp 8 is turned on, the high-frequency output is transmitted to the induction coil 3 by switching the changeover switch 7 to the induction coil 3 side.

Therefore, the inductance value of the auxiliary coil 6 is set smaller than the inductance value of the induction coil 3 so that the high frequency oscillator 4 oscillates but the high frequency voltage induced in the auxiliary coil 6 becomes equal to or lower than the starting voltage of the lamp 8. . By setting the inductance value of the auxiliary coil 6 in this way, the lamp 8 is not turned on by the high frequency power supplied to the auxiliary coil 6 before the lamp is turned on, but the wall temperature of the lamp bulb 2 is lowered by the ohmic loss of the auxiliary coil 6. Rises. Along with this, the mercury vapor pressure in the bulb 2 rises, lighting becomes easier even at low temperatures, the luminous flux immediately after lighting rises, and the rising characteristics until stable light output is improved.

The position where the auxiliary coil 6 is wound around the valve 2 is
It is desirable that the lamp 8 be in the coldest position during lighting.

Further, the position around which the valve 2 is wound is not limited to the lower portion of the valve 2 as shown in FIG. 2, but may be wound around the position shown in FIG. That is, the embodiment shown in FIG. 3 is characterized in that the exhaust pipe 9 is connected to the lower portion of the valve 2 and the auxiliary coil 6 is wound around the exhaust pipe 9. With this configuration, the exhaust pipe 9 has the same effect as that of the above-described embodiment, that is, the wound auxiliary coil 6 is provided.
The effect of raising the tube wall temperature by a minute current that flows at a low temperature is obtained, and since no current flows through the auxiliary coil 6 while the lamp 8 is lit, the coldest point of the lamp 8 is the exhaust pipe 9
Occurs at the tip-off portion of the lamp, and the effect of controlling the coldest spot of the lamp 8 can be obtained.

(Effects of the Invention) As described above, the present invention winds an auxiliary coil around a part of a valve, and connects the auxiliary coil in parallel with an induction coil via a changeover switch. It is set smaller than the induction coil so that the high-frequency voltage induced in the auxiliary coil is less than the starting voltage of the lamp, that is, the inductance value of the auxiliary coil is slightly shifted from the resonance point and set to a value that does not turn on the lamp. By supplying high-frequency power to the auxiliary coil before the lamp is turned on by the changeover switch, the auxiliary coil heats sufficiently, a so-called preheating effect is obtained, and it becomes easy to light even at low temperature. Also, the luminous flux immediately after lighting is increased, and the rising characteristic until stable light output is also improved.

Therefore, according to the present invention, there is an effect that the reduction of the light output at the time of cold start is suppressed, and the uniform light output can be obtained without being largely influenced by the ambient temperature.

In addition, the power supply source to the auxiliary coil as a preheating means,
Since the high-frequency oscillator that supplies high-frequency power to the induction coil can also serve as the induction coil, there is an additional effect that an extra filter circuit or the like which is required when a heater or the like is used unlike the conventional case is not required.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a partial cross section showing a conventional example, FIG. 2 is a schematic configuration diagram showing an embodiment of the present invention, and FIG. 3 is a cross sectional view showing a main part of a different embodiment of the present invention. is there. 2 ... Valve, 3 ... Induction coil, 4 ... High frequency oscillator, 6 ...
Auxiliary coil, 7 ... Changeover switch.

Claims (1)

[Claims] 1. An electrodeless discharge lamp device in which a discharge gas enclosed in a bulb is caused to emit light by supplying high frequency power to an induction coil wound outside the bulb, and an auxiliary coil is provided in a part of the bulb. Along with winding, the auxiliary coil is connected in parallel with the induction coil via a changeover switch, and the inductance value of the auxiliary coil is induced so that the high frequency voltage induced in the auxiliary coil is equal to or lower than the starting voltage of the lamp. An electrodeless discharge lamp device characterized by being set smaller than the coil.