JP2555080B2 - Electrodeless discharge lamp lighting device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrodeless discharge lamp lighting device that emits light by applying a high-frequency electromagnetic field to an electrodeless discharge lamp.

BACKGROUND ART Conventionally, an electrodeless discharge lamp lighting device of this type, which emits light by applying a high-frequency electromagnetic field to an electrodeless discharge lamp, has a transparent glass bulb or an inner surface coated with a phosphor as shown in FIG. An electrodeless discharge lamp 1 in which a discharge gas (for example, mercury and a noble gas) such as an inert gas or a metal vapor is enclosed in a ring-shaped glass bulb 1a, which is disposed close to the outer circumference of the electrodeless discharge lamp 1. The high-frequency power supply coil 2 and the high-frequency power source 3 connected to the coil 2 are provided. The high-frequency power source 3 supplies a high-frequency current of several to several 100 MHz to the electrodeless discharge lamp 1. It was designed to emit high-frequency power. When used as a general illumination light source, an electrodeless discharge lamp 1 in which a phosphor is applied to the inner surface of the glass bulb 1a and low-pressure mercury vapor is sealed is used, and accelerated by applying a high-frequency electromagnetic field. An electron collides with a mercury atom, and the phosphor is excited by resonant ultraviolet rays emitted by the mercury atom excited by this collision to emit visible light (light according to Stokes' law). When the electrodeless discharge lamp 1 that emits light in this way is compared with a commonly used fluorescent lamp with an electrode, a blackening phenomenon occurs due to exhaustion of the cathode and scattering of the electrode material because there is no electrode. However, there is an advantage that it has a long life. As in the case of a fluorescent lamp, the mercury vapor pressure in the tube changes depending on the ambient temperature, which causes the light output to change and the discharge starting voltage to change.

FIG. 5 shows the optical output φ and the starting voltage with respect to the ambient temperature T.
The change of Vs is shown. The solid line shows the change of the optical output φ, and the dotted line shows the change of the starting voltage Vs. As is clear from FIG. 5, the ambient temperature T at which the optical output φ becomes the maximum and the start Voltage Vs
It can be seen that it is desirable to maintain these temperatures all the time in order to stably turn on the electrodeless discharge lamp 1 since there is a temperature region where there is little fluctuation. Usually, this temperature range is set around room temperature. However, when such an electrodeless discharge lamp 1 is used as a high-intensity linear light source for a copying machine, heat dissipation becomes worse as the lamp current increases,
There is a problem that the temperature of the glass bulb 1a rises and the mercury vapor pressure becomes excessive, so that the ultraviolet absorption becomes remarkable and the luminous efficiency is reduced. Therefore, conventionally, as a measure for increasing the mercury vapor pressure, the coldest spot temperature has been lowered by moving a part of the tube wall of the glass bulb 1a away from the main discharge part. That is, in the case of FIG. 6, the exhaust pipe portion of the ring-shaped glass bulb 1a is separated from the discharge portion indicated by the dotted line to be the coldest spot portion 1b, and the coldest spot temperature is lowered.

In such a conventional example, when high-frequency electric power is supplied to the coil 2 and a high-frequency electromagnetic field is applied to the electrodeless discharge lamp 1, the electric field strength near the tube wall of the glass bulb 1a increases and an annular discharge is generated. It occurs as shown by the dotted line, and the coldest spot temperature is the temperature of the exhaust pipe part formed at a position distant from the discharge part. However, in such a conventional example, when the ambient temperature deviates from the optimum temperature, the coldest spot temperature changes, and there is a problem that the luminous efficiency decreases. For example, in the actual usage environment, the ambient temperature changes between -10 ℃ and + 40 ℃, so
When the maximum light output is obtained at room temperature at 25 ° C., the light output is remarkably reduced especially at low temperatures.

In order to solve the above-mentioned problems, it is sufficient to arrange a heater for heating around the glass bulb 1a and the exhaust pipe portion which is the coldest spot portion 1b, and always maintain the optimum temperature condition. Since the output frequency of the high frequency power supply 3 is set to a high frequency (for example, VHF band of 10 MHz or more), if a resistance element is placed around the coil 2 as a heating element, the floating between the resistance element and the coil 2 will occur. Due to the capacitance or mutual inductance, there are problems that the impedance matching condition between the high frequency power supply 3 and the discharge load circuit including the coil 2 and the electrodeless discharge lamp 1 is disturbed, and power loss increases.

[Object of the Invention] The present invention has been made in view of the above points, and an object thereof is to provide an electrodeless discharge lamp lighting device capable of preventing a decrease in light output due to a decrease in ambient temperature. To provide.

DISCLOSURE OF THE INVENTION (Structure) The present invention relates to an electrodeless discharge lamp in which a discharge gas such as an inert gas or a metal vapor is sealed in a glass bulb, and a high-frequency power supply arranged closely along the electrodeless discharge lamp. Coil for
In an electrodeless discharge lamp lighting device consisting of a high frequency power source connected to the coil, a heater for heating the discharge part, which is arranged near the tube wall of the glass bulb, and a coldest spot, which is arranged near the coldest spot of the glass bulb. A heater for heating, an ambient temperature detecting means, and a heating control means for controlling energization to both heaters based on the output of the high frequency power source and the output of the ambient temperature detecting means are provided, and discharge is performed when the high frequency power source output is not applied to the coil. Preventing a decrease in light output due to a decrease in ambient temperature by forming the heating control means so that the heater for part heating is energized and the heater for heating the coldest spot is energized when the ambient temperature is below a predetermined value. Then, an electrodeless discharge lamp lighting device capable of obtaining a stable light output immediately after starting is provided.

(Embodiment) FIG. 1 shows an embodiment of the present invention, which is a glass bulb.
An electrodeless discharge lamp 1a in which a discharge gas such as an inert gas or a metal vapor is sealed in 1a, a coil 2 for high-frequency power feeding which is arranged close to the electrodeless discharge lamp 1, and is connected to the coil 2 In the same electrodeless discharge lamp lighting device as that of the conventional example, which comprises the high-frequency power source 3, the heater 4 for heating the discharge part disposed near the tube wall of the glass bulb 1a, and the coldest spot (exhaust pipe part) of the glass bulb 1a. ) Heater 5 for heating the coldest spot located close to 1b, ambient temperature detecting means 6, and heating control for controlling energization of both heaters 4 and 5 based on the output of high frequency power source 3 and the output of ambient temperature detecting means 6. Means 7 for providing a high frequency power source 3
The heating control means 7 is formed so that the heater 4 for heating the discharge part is energized when the output is not applied to the coil 2 and the heater 5 for heating the coldest spot part is energized when the ambient temperature is below a predetermined value. It is a thing. In the embodiment, the heater 4 for heating the discharge part is provided on the tube wall excluding the light emitting surface of the glass bulb 1a, and the tube wall surface is treated with a white paint having a large light reflectance in order to have a light reflecting function. are doing. Also, both heaters 4 and 5 are equipped with a glass bulb 1 to improve heating efficiency.
Although the coil 2 is disposed in close contact with the tube wall of a and the coil 2 is disposed thereon, the coil 2 may be reversed if importance is attached to the coupling efficiency of the coil 2. In this case, if the tube wall surface of the coil 2 is made into a light-reflecting surface by gloss finish or white coating, the light utilization rate can be increased.

Further, the high frequency power supply 3 is formed of a high frequency oscillating section 3a and a power amplifying section 3b, and a high frequency signal generated by the high frequency oscillating section 3a is amplified by the power amplifying section 3b to feed the coil 2. When the power amplification section 3b is operating, the power supply signal Vo is output to inform the heating control means 7 that the power is in the power supply state. In the heating control means 7,
This power supply signal Vo and the temperature sensor of the ambient temperature detecting means 6
Both heaters 4 and 5 are controlled based on the 6a output, and the power supply signal V
When o is not output and the output of the high frequency power source 3 is not applied to the coil 2, the heater 4 for heating the discharge part is energized to heat the discharge part of the glass bulb 1a, while the ambient temperature When the temperature is below a predetermined value, the heater 5 for heating the coldest spot is energized to heat the coldest spot 1b, and the decrease in the light output due to the decrease in the ambient temperature is prevented and the start is performed. Immediately after that, a stable light output can be obtained. In the embodiment, the DC power supply 10 for supplying the circuit power to each part is applied to each part via the main switch 11, and the power supply to the power amplification part 3b is also controlled by the lighting switch 12. There is. By forming the power supply circuit in this way, it is possible to realize a light source for a copying machine that requires stable light output immediately after lighting. That is,
If the main switch 11 is turned on in advance, the non-power-supply discharge lamp 1 is in a preheated state as needed (according to the ambient temperature), and the lighting switch 12 is turned on after each use. , The electrodeless discharge lamp 1 always lights up with the maximum light output,
In addition, a stable light output is obtained immediately after lighting.

FIG. 2 is a diagram showing a specific configuration of both heaters 4 and 5,
FIG. 2 (a) shows resistance elements 4a and 5a made of metal thin films of both heaters 4 and 5 formed on a heat-resistant insulating film 9 such as a polyimide resin film.
Inductance elements 4b and 5b are provided in series with the resistance elements 4a and 5a, and the inductance elements 4b and 5b function as a high frequency choke to increase the high frequency impedance of the heater circuit arranged close to the coil 2. . Therefore, it is possible to reduce the heat loss due to the electromagnetic induction generated by the high frequency magnetic flux interlinking with the conductor loop of the heater circuit. In FIG. 2 (a), the dimension in the longitudinal direction is reduced, but in reality, the dimension is equivalent to the length of the discharge part, and as shown in FIG. 3, a ring-shaped glass is used. The valve 1a is mounted so as to enclose it.

2 (b) and (c) show specific examples of the inductance elements 4b, 5b. In FIG. 2 (b), the inductance elements 4b, 5b are formed by tightly meandering bent lines, In (c), the inductance elements 4b and 5b are formed by the spiral line formed by using the both sides of the insulating film 9 by the through holes (the spiral conductive pattern is formed on the front surface and the wiring pattern to the spiral center is formed on the rear surface). In any case, it is formed so as to exhibit a sufficiently high impedance in the frequency band used. In this case, the inductance elements 4b and 5b are dispersedly formed instead of being collectively formed at one place (for example, a terminal portion).
The reason is the operating frequency (the frequency of the high frequency power supply 3 output)
When the wavelength of is close to or shorter than the length of the conductors (heat-generating resistance elements 4a, 5a) arranged close to the coil 2, the interaction between the conductor and the coil 2 becomes large. This is to prevent a part of the high frequency power from being consumed in the conductor. In order to reduce the interaction, it is necessary to divide the conductor at a high frequency so that the length is at least 1/10 or less of the used wavelength. Second
2D shows the equivalent circuit of FIG. 2A,
The resistance elements 4a and 5a are separated at high frequencies by an LC circuit formed by the inductance component L and the stray capacitance component C of the inductance elements 4b and 5b. Figure 2 (e)
In (f), by providing the counter electrode 20 on the back surface of the insulating film 9, the stray capacitance component C is increased to be positively utilized, and the impedance in the used frequency band can be easily increased. It is a thing. FIG. 2 (g) shows a cross-sectional view thereof, in which the resistance element 4a formed on both surfaces of the insulating film 9 and the counter electrode 20 are connected to each other through the through-hole portion 21 and the resistance element 4a. The counter electrodes 20 are covered with protective films 22 and 23.

By the way, when the lengths of the resistance elements 4a and 5a are negligible compared to the wavelength of the operating frequency, the lumped-constant-type inductance element 4b 'composed of a toroidal core type coil as shown in FIG. It may be connected in series to the terminal part of 5a). In this case, since the toroidal core is used, the impedance can be made sufficiently large.

[Advantages of the Invention] As described above, the present invention provides an electrodeless discharge lamp in which a discharge gas such as an inert gas or a metal vapor is sealed in a glass bulb, and a high-frequency power supply disposed closely along the electrodeless discharge lamp. In an electrodeless discharge lamp lighting device comprising a coil for heating and a high-frequency power source connected to the coil, a heater for heating the discharge part, which is arranged near the wall of the glass bulb, and a heater which is arranged near the coldest spot of the glass bulb. A heater for heating the coldest spot, an ambient temperature detecting means, and a heating control means for controlling energization to both heaters based on the high frequency power source output and the ambient temperature detecting means output are provided, and the high frequency power source output is applied to the coil. Since the heating control means is formed so as to energize the heater for heating the discharge part when the ambient temperature is not higher than a predetermined value and to energize the heater for heating the coldest spot when the ambient temperature is not higher than a predetermined value, There is an effect that it is possible to obtain a stable light output immediately after starting by preventing the decrease of the light output due to the lowering.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of one embodiment of the present invention, FIG. 2 (a) is a front view of a main part of the same, and FIGS. 2 (b) and (c) are enlarged front views showing a specific example of the same part of the same. FIG. 6D is an equivalent circuit diagram of the main part of the same, FIG. 8E is a front view showing a concrete example of the main part of the same, FIG. 9G is a sectional view of the main part of the same, and FIG. FIG. 4 (a) is a perspective view of an essential part of the other embodiment, FIG. 4 (b) is a front view of an essential part of the same, and FIG. 5 is an operation explanatory view of an electrodeless discharge lamp. FIG. 6 is a schematic configuration diagram of a conventional example. 1 is an electrodeless discharge lamp, 2 is a coil, 3 is a high frequency power source, 4 is a heater for heating the discharge part, 5 is a heater for heating the coldest spot, and 4a, 5
a is a resistance element, 4b and 5b are inductance elements, 6 is an ambient temperature detecting means, 7 is a heating control means, and 9 is an insulating film.

Continuation of the front page (56) Reference JP-A-59-63697 (JP, A) JP-A-62-163296 (JP, A) JP-A-63-215158 (JP, A) JP-A-63-215159 (JP , A)

Claims (3)

(57) [Claims] 1. An electrodeless discharge lamp in which a discharge gas such as an inert gas or a metal vapor is sealed in a glass bulb, and a coil for high-frequency power supply, which is arranged close to the electrodeless discharge lamp.
In an electrodeless discharge lamp lighting device consisting of a high frequency power source connected to the coil, a heater for heating the discharge part, which is arranged near the tube wall of the glass bulb, and a coldest spot, which is arranged near the coldest spot of the glass bulb. A heater for heating, an ambient temperature detecting means, and a heating control means for controlling energization to both heaters based on the output of the high frequency power source and the output of the ambient temperature detecting means are provided, and discharge is performed when the high frequency power source output is not applied to the coil. An electrodeless discharge lamp lighting device, characterized in that heating control means is formed so that the heater for heating the part is energized and the heater for heating the coldest spot is energized when the ambient temperature is equal to or lower than a predetermined value. 2. The electrodeless discharge lamp lighting device according to claim 1, wherein an inductance element exhibiting high impedance is connected in series with a resistance element which constitutes both heaters. 3. The electrodeless discharge lamp lighting device according to claim 2, wherein the resistance element and the inductance element of both heaters are formed on the same insulating film.