JPS6240198A - Electrode-free discharge lamp apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

"Technical Field 1 The present invention applies a high frequency voltage to an external electrode provided outside a bulb containing a nitrogen gas to cause a discharge, and converts the ultraviolet rays generated by the discharge into visible light using a phosphor. The present invention relates to an electrodeless discharge lamp device used. [Background Art] Fig. 5 shows a block diagram of an electrodeless discharge lamp device. Its configuration includes, for example, discharging a rare gas such as argon and a metal vapor such as mercury. A pair of external electrodes 4, 4 made of a metal conductor are arranged near the external tube end of the bulb 3 sealed as a gas, and power is supplied from the power source 1 between the two electrodes 4, 4. A high-frequency voltage generated by the oscillation circuit 2 is applied to generate a discharge in the bulb 3 to excite metal vapors such as mercury to a metastable state, and these metal vapors are released when they relax to the ground state. Ultraviolet #il (in the case of mercury, mainly wavelengths 253.7t+m and 184.9nm)
) is converted into visible light by a phosphor (not shown) coated inside the bulb 3 and used as a light source for illumination or a light source for display. FIG. 6 shows an example of a specific circuit of the conventional oscillation circuit 2, whose basic configuration is a wrap circuit that stabilizes the oscillation frequency. below,
The operation of the electrodeless discharge lamp device will be explained based on FIG. Although the oscillation circuit 2 shown in FIG. 6 uses a piboraton sister as the oscillation element Q1, it goes without saying that other active elements, such as a MOSFET, may also be used. A pulsating voltage obtained by rectifying the AC voltage of the power supply 1 by a diode bridge DB (not shown) is smoothed by a smoothing capacitor C8 to form a DC power supply E, and its terminal voltage is divided by resistors R1 and R2. When a suitable bias voltage vb is applied to the base B of the oscillation element Q1 via the resistor R5, a collector current Ic flows and the oscillation element Ql acts as an amplifier. However, the oscillation coil L11con'
By a resonant circuit consisting of capacitor C+ -C2-C*,
Since a part of the oscillation output is fed back to the input side, sustained oscillation can be started if the values of the above circuit constants are appropriately selected. The oscillation output of this oscillation circuit 2 is supplied to the pulp 3 of the electrodeless discharge lamp by connecting the external electrodes 4, 4 to both ends of the oscillation coils L, +. Therefore, the discharge gas starts discharging in the pulp 3 of the electrodeless discharge lamp, excites the mercury atoms to a metastable state, and the water! The ultraviolet light emitted when the Tg molecules relax to the ground state is converted into visible light by the phosphor coated on the inner wall surface of the pulp 3. As is clear from the above explanation, the color of the emitted light of the electrodeless discharge lamp is uniquely determined by the type a of the phosphor coated on the inner wall surface of the pulp 3, and in the conventional electrodeless discharge lamp,
Since the above-mentioned phosphor was composed of only one type, the emitted light color could not be changed, and in order to obtain different emitted colors, multiple electrodeless discharge lamps with different emitted colors were required. there were. [Objective of the Invention 1 The present invention has been made in view of the above-mentioned ff1 point, and an object of the present invention is to provide an electrodeless discharge lamp device that can freely change the color of emitted light. [Disclosure of the Invention] The electrodeless discharge lamp device of the present invention comprises an oscillation circuit that receives power from a power source and generates a high-frequency voltage, a pulp in which a metal vapor such as a rare gas or mercury is sealed as a discharge gas, and the pulp. at least one pair of external electrodes provided on the outside of the
An electrodeless discharge lamp device that applies the high-frequency voltage between the external electrodes to generate a discharge in the bulb, and converts ultraviolet rays generated by the discharge into visible light using a phosphor coated on the inner wall surface of the pulp. In this step, two or more types of phosphors having different luminescent colors are coated on the inner wall surface of the pulp, and the high frequency potential of each of the pair of external electrodes is relatively changed to determine the position of the luminescent center within the pulp. The above-mentioned oscillation circuit is provided with a light emission center moving means for moving the light emission center. Embodiment 1 FIG. 1 illustrates the vI configuration of the pulp 3 and external electrode 4 at 4 b of an electrodeless discharge lamp according to an embodiment of the present invention. The inner wall surface of the pulp 3 has a structure in which the right half is coated with a red-emitting phosphor R, and the left half is coated with a green-emitting phosphor G, which is the same as the conventional example. , is a gangway type oscillation circuit, but other oscillation circuits, such as Hartley type and Colpitts oscillation circuits, are similar, so a description thereof will be omitted. The bias circuit of this embodiment is a DC power supply E (hereinafter, the value of the terminal voltage is also indicated by E).
The configuration is such that the midpoint of a series circuit of resistors R, , R2 connected to the base B of an oscillation element Q made of a bipolar transistor is connected by a resistor R1. The above resistance R1
supplies the voltage of the DC power supply E divided by the resistors R, , R2 to the base B of the oscillation element Q as the bias voltage vb, and the high-frequency current flows through the bias circuit resistors R, , R
2, and an inductance may be used instead of the resistor R1. Further, the resonant circuit of this embodiment is composed of an oscillation coil, a capacitor C2-C, and two variable capacitors Ca and Cb connected in series to both ends of the oscillation coil Ll. An external electrode 4a is connected to the terminal to which Ca is connected, and an external electrode 4h is connected to the terminal to which capacitor Cb is connected to the horse mackerel bowl. The capacitances of the variable capacitors Ca and Cb change in conjunction with each other. For example, if the capacitance of the variable capacitor Ca increases, the capacitance of the variable capacitor cb decreases accordingly, and conversely, the capacitance of the variable capacitor Ca decreases. If the capacitance of the variable capacitor cb is increased, the capacitance of the variable capacitor cb increases accordingly. Note that the variable capacitors Ca and Cb correspond to the light emission center moving means. When the voltage of the power supply 1 is applied and the oscillation circuit 2 starts oscillating, discharge occurs inside the bulb 3 of the electrodeless discharge lamp and ultraviolet rays are emitted as described above.
The right half emits red light and the left half emits green light, but the relative intensity of the two colors changes depending on the capacitance of the variable capacitor Car Cb. be. The explanation will be given below. First, since the problem is the high frequency potential, we will discuss capacitor C2 → variable capacitor Ca - oscillation coil L1
→Variable fund capacitor cb→Capacitor C1→Capacitor C
limited to closed circuits consisting of 2. Furthermore, capacitor C2
It is assumed that the values of capacitor C1 and capacitor C1 are designed so that their respective orders are approximately the same. Now, assuming that the value of variable capacitor Ca is set smaller than the value of variable capacitor cb, the high frequency impedance of the series circuit of capacitor C2 and variable capacitor Ca is equal to the high frequency impedance of the series circuit of capacitor C1 and variable capacitor cb. Since it becomes larger than the high frequency impedance, the high frequency potential of the external electrode 4a becomes higher than the high frequency potential of the external electrode 4b. That is, in this case, the external electrode 4a is the hot terminal and the external electrode 4b is the cold terminal, so the light emitting state of the bulb 3 is brightest near the external electrode 4a, which is the hot terminal, and becomes brighter as it approaches the external electrode 4b. The brightness decreases, and the area near the external electrode 4b, which serves as the cold terminal, becomes the darkest. As mentioned above, the phenomenon that a brightness gradient occurs inside the pulp 3 is due to the loop formed by the stray capacitance distributed between the bulb 3 and the earth and the discharge path inside the bulb 3. This occurs because a portion of the high frequency current flowing from the II element to the cold terminal is gradually shunted. Contrary to the above case, when the capacitances of the variable capacitors Ca and Cb are set such that Ca>Cb, the external electrode 4a becomes a cold terminal, the external electrode 4b becomes a hot terminal, and the above-mentioned light emission state is also reversed. Furthermore, when the capacitances of the variable capacitors Ca and Cb are made almost equal, as described above (the capacitance values of the capacitor C2 and the capacitor C are on the same order), the high frequency of the external electrodes 4a and 4b is The potential difference almost disappears, and the luminance distribution inside the bulb 3 becomes almost uniform.As is clear from the above explanation, in the electrodeless discharge lamp device having the configuration of this embodiment, the variable capacitor provided as the light emission center moving means By changing the capacitance of Ca and Cb, the luminance distribution inside the bulb 3 of the electrodeless discharge lamp can be made uniform, or the luminance distribution from the external electrode 4a to the external electrode 4 can be made uniform.
An appropriate luminance gradient may be provided between the external electrodes 4a and 4b, or in extreme cases, the external electrodes 4a and JJ+l! Mff#4KjL#2r%m
The position of the emission center can be changed in various ways, such as f, jfi4musi-no-3-9raC. Therefore, if two or more types of phosphors with different luminescent colors are applied to the inner wall surface of the bulb 3 at different positions, the luminescent color of the pulp 3 as a whole can be changed by moving the position of the luminescent center. One color or several phosphors! It can be a mixed color of 4 types. That is, in this embodiment, it is possible to obtain light emission of either green or red, or a mixture of these colors. Although this embodiment shows a circuit using variable capacitors Ca and Cb as the light emission center moving means, any circuit that can relatively change the value of the high frequency potential inside the bulb 3 may be used. It doesn't matter if it's something.

Embodiment 2 FIG. 3 shows an electrodeless discharge lamp device according to another embodiment of the present invention. The oscillation circuit 2 of this embodiment is similar to the circuit of embodiment 1 shown in FIG. 1, and the difference from embodiment 1 is that a diffusion globe 5 covering the entire pulp 3 is provided. , in the structure of the bulb 3 which becomes the light emitting part. That is, the shape of the bulb 3 of the electrodeless discharge lamp of this example is not the straight tube type shown in Example 1, but is approximately U-shaped, and the inner wall surface has a phosphor R whose luminescent color is red in the center. , green and blue phosphors G and B are applied to both ends thereof, respectively. Furthermore, the light emitted from the bulb 3 is diffused and mixed by the diffusion globe 5, and the light emitted from the bulb 3 serving as a light source is prevented from directly entering the eyes, thereby reducing glare. The high frequency voltage of the oscillation circuit 2 described in Example 1 is applied to the external electrodes 4a and 4b (not shown) at both ends of the bulb 3 of the electrodeless discharge lamp having the above configuration, and the variable capacitor Ca is
, Cb, the light emitted from the diffusion globe 5 can be varied into blue, green, or yellow, which is a mixture of these colors.

Embodiment 3 FIG. 4 shows a configuration diagram of still another embodiment of the present invention. The difference from the electrodeless discharge lamp device of Example 2 shown in FIG. The structure consists of three U-shaped tubes coated with the same material, which are alternately lined up in opposite directions so that the starting and ending points are lined up next to each other. With the above configuration, three U-shaped tubes each coated with a different luminescent color on the inner wall are fused together, and the inner wall is coated with different luminescent colors. Since one valve 3 can be manufactured,
A feature is that the method for manufacturing the valve 3 is simplified. Furthermore, as described in Example 2, due to the effect of the diffusion globe 5, the brightness of each of the above colors, that is, blue, red, and green, can be made almost the same, which can be used for display lighting, etc. effective. [Effect of the invention 1 of the present invention! An electrode discharge lamp device is an electrodeless lamp that applies a high-frequency voltage between external electrodes to generate a discharge within the pulp, and converts the ultraviolet rays generated by the discharge into visible light using a phosphor coated on the inner wall of the bulb. In a discharge lamp device,
Two or more types of phosphors with different emission colors are coated on the inner wall surface of the bulb, and the high frequency potential of each of the pair of external electrodes is relatively changed to move the position of the emission center within the bulb. Since the oscillation circuit is equipped with a light emitting center moving means, it is the only variable color fluorescent lamp that can change the emitted color by changing the position of the light emitting center and emitting phosphors of different colors. Since it can be constructed from regular bulbs, it is possible to provide a small and lightweight variable color fluorescent lamp at low cost.
Since there are no electrodes inside the bulb, there is no wear on the electrodes due to ions, and not only does it have a long flickering life, but there is no reduction in luminous flux near the electrodes, making it ideal for display devices. be effective.

[Brief explanation of drawings]

FIG. 1 is a side view of the vicinity of the pulp of Example 1 of the present invention, and FIG.
The figure is a circuit diagram of the electrodeless discharge lamp device of Example 1, same as above,
The figure is a configuration diagram of the second embodiment same as the above, and FIG. 4 is the block diagram of the third embodiment same as the above.
Fig. 5 is a conventional circuit diagram, in which 1 is a power supply, 2
is an oscillation circuit, 3 is a valve, 4 a, 4 b are external electrodes, 5 is a diffusion globe, Ca and Cb are variable capacitors, R
, G, and B are phosphors that emit red, green, and blue colors, respectively.

Claims (1)

[Claims] (1) An oscillator circuit that receives power from a power source and generates a high-frequency voltage, a bulb sealed with a rare gas or metal vapor such as mercury as a discharge gas, and at least one pair of external electrodes provided outside the bulb. and applying the high frequency voltage between the external electrodes to generate a discharge within the bulb,
In an electrodeless discharge lamp device that converts ultraviolet rays generated by discharge into visible light using a phosphor coated on the inner wall surface of the bulb, two or more types of phosphors with different emission colors are coated on the inner wall surface of the bulb. An electrodeless discharge lamp characterized in that the oscillation circuit is further provided with a light emission center moving means for moving the position of the light emission center within the bulb by relatively changing the high frequency potential of each of the pair of external electrodes. Device.