JPH09231949A - Electrodeless low pressure discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve starting property, light flux, and the life of a discharge lamp by controlling a high frequency electromagnetic field generated by an induction coil installed in a discharge gas-sealed bulb. SOLUTION: In an electrodeless low pressure discharge lamp 1, a phosphor 9 is applied to a discharge space inner wall inside a discharge gas-sealed and light tramsmissive material-made bulb 1, high frequency power flows from a lighting circuit 8 into a matching circuit 6 in a space 5 through a cable 7, the high frequency power is applied to an induction coil 2 from the matching circuit 6 so as to generate a high frequency electromagnetic field to cause discharge gas to exciting emit light, and the phosphor 9 emits light. The induction coil 2 is provided in the hollow (k) of the bulb 1, and a metal cylindrical body 3 which has an opening on a deep side of the hollow (k) of the bulb 1 having the same potential with the earth side of a high frequency lighting device and has excellent thermal conductivity is inserted between the bulb 1 and the induction coil 2. A slit 3a which is in a nearly vertical direction to the winding direction of the induction coil 2 is provided in the metal cylindrical body 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention does not have a main electrode inside the bulb, and a high-frequency electromagnetic field is applied from outside the bulb to the discharge gas sealed in the bulb to cause a high-frequency discharge inside the bulb. The present invention relates to an electrodeless low-pressure discharge lamp that emits discharge gas to generate light.

[0002]

2. Description of the Related Art FIG. 13 is a front view of a conventional electrodeless low-pressure discharge lamp partially cut away. The figure will be described. The electrodeless low-pressure discharge lamp L is constructed by disposing an induction coil 2 in the center of a bulb 1. For example, when a high frequency current of 2.65 MHz is generated by the inverter and the high frequency current is passed through the induction coil 2, the induction coil 2
A high frequency electromagnetic field is generated from the high frequency electromagnetic field, and this high frequency electromagnetic field is magnetically coupled with the ferrite 10 installed inside the induction coil 2 to generate a magnetic field, and the valve 1 arranged outside the induction coil 2 is generated. A high-frequency electromagnetic field is supplied to the discharge plasma 4 therein, the low-pressure mercury that is the discharge plasma 4 emits ultraviolet rays, and the ultraviolet rays are converted into visible light by the phosphor 9 to turn on the discharge lamp L.

[0003]

In the above electrodeless low pressure discharge lamp, the ferrite 10 plays an important role in supplying the high frequency electromagnetic field from the induction coil 2 to the discharge plasma 4. Induction coil 2 or ferrite 10
Is enclosed in the valve 1 that generates heat, and the induction coil 2 and the ferrite 10 themselves generate heat, resulting in power loss. In particular, the power loss of the ferrite 10 increases as the temperature increases. So ferrite 10
In order to dissipate the heat, a copper rod heat pipe 11 is used to suppress power loss. Also, if a high-frequency electromagnetic field is applied to an air-core coil (not shown) that does not use the ferrite 10, power loss occurs due to internal resistance, and the internal-core coil resistance value increases with temperature. To do. When the resistance value increases, the power loss increases and the luminous flux decreases. In addition, when the discharge lamp L shifts to the lighting state, heat radiation from the bubble 1 itself starts, and the heat is conducted to the adjacent metal parts such as the induction coil 2, the ferrite 10 and the heat pipe 11 to cause power loss. This causes a large decrease in luminous flux.

When starting with a high-frequency discharge of several MHz to several tens of MHz, a glow discharge is first generated in the bulb 1 by the high-frequency electric field discharge, and then an arc discharge is generated by the high-frequency electromagnetic field, and the discharge lamp L is lit. Transition to the state. When the metal tubular body 3 to be discharged has a loop of metal or the like in the vicinity of the air-core coil in the direction of the induction field of the high-frequency electromagnetic field, a high-frequency eddy current is generated in the metal to cause power loss, and the discharge lamp L When the discharge plasma 4 is not generated at the time of starting, the starting power may combine with the metal near the induction coil 2 to make it difficult to start. Since the eddy current is generated in the loop-shaped metal shield, if the metal tubular body 3 or the like is looped, an induction electric field is generated in the loop to consume power and power for starting the discharge lamp L. Cannot be supplied, and the luminous flux is also impaired.

Further, the induction electric field at the time of transition from the electric field discharge to the induction electric field discharge or during lighting plays an important role in the electrodeless low pressure discharge lamp, but the induction electric field is naturally strong in the vicinity of the induction coil 2 and has a high frequency. Even in the case of discharge, the discharge plasma 4 that is lit depending on the relative position of the bulb 1 and the induction coil 2
Is determined, and it is a very difficult technique to form the discharge plasma 4 that matches the shape of the bulb 1.

Further, at the time of starting the high frequency discharge, if a metal plate having the same potential as the ground side of the lighting circuit 8 is inserted between the induction coil 2 and the bulb 1 containing the discharge plasma 4, the high frequency electric field generated from the induction coil 2 will be generated. There is a problem that it is difficult to shield and transfer to electric field discharge. In addition, in the electrodeless low-pressure discharge lamp, the induction discharge forms a discharge loop in the bulb 1 to form discharge plasma 4 at a certain distance from the tube wall coated with the phosphor 9. High frequency high electric field discharge
There is a tendency that the fluorescent substance 9 is generated in the fluorescent substance 9 in the bulb 1 near the induction coil 2 which supplies the high frequency and high electric field, and the fluorescent substance 9 is blackened, which also causes a problem of shortening the lamp life.

In view of the above problems, the present invention controls the high frequency electromagnetic field generated from an induction coil installed in a bulb in which a discharge gas is sealed so that the startability, luminous flux and lamp life of the discharge lamp can be improved. Its purpose is to significantly improve

[0008]

To achieve the above object, in the electrodeless low-pressure discharge lamp according to the present invention, the invention of claim 1 is the interior of a bulb made of a translucent material and filled with a discharge gas. In the electrodeless low-pressure discharge lamp in which a phosphor is applied to the inner wall of the discharge space, high-frequency power is applied to the induction coil to generate a high-frequency electromagnetic field to excite the discharge gas to emit light, and the phosphor emits light. Has a hollow,
By providing an induction coil in the hollow of the bulb, a metal tubular body having good thermal conductivity and having an opening at the back side of the hollow of the bulb having the same potential as the ground side of the high-frequency lighting device is used. And a slit substantially perpendicular to the winding direction of the induction coil is provided in a part of the metal tubular body.

According to a second aspect of the present invention, in the first aspect of the present invention, the number of slits provided in the metal cylindrical body facing the valve in a direction substantially perpendicular to the winding direction of the induction coil is four.
It is characterized by being more than a book. The invention of claim 3 is characterized in that, in the invention of claim 2, one or a plurality of holes are provided in a portion of the metal tubular body facing the valve.

According to a fourth aspect of the invention, in the invention of the second aspect or the third aspect of the invention, the metal tubular body has an opening at the inner side of the recess of the valve and the other end is closed, and the metal tubular body is formed. One or more holes are provided near the closed end of the body and close to the valve. The invention of claim 5 is characterized in that, in the invention of claim 2 or the invention of claim 3, a part of the high potential side of the induction coil is in contact with the valve through the hole of the metal cylindrical body.

The invention of claim 6 is characterized in that, in the invention of claim 2 or the invention of claim 3, a part of the high potential side of the induction coil is in contact with the valve through the hole of the metal cylindrical body. To do. The invention of claim 7 is the invention of claim 2, the invention of claim 3, the invention of claim 4, the invention of claim 5, or the invention of claim 6, wherein the metal tubular body and the induction coil are grounded of the lighting device. It is characterized in that it has the same high-frequency potential as that of the side, and the winding start of the induction coil on the side of the ground potential is located near the opening of the metal tubular body.

Next, the operation of the electrodeless low pressure discharge lamp according to the present invention will be described. According to the first aspect of the invention, an induction coil is provided in the recess of the bulb to provide a metal tubular body having good thermal conductivity and having an opening at the back side of the recess of the bulb having the same potential as the ground side of the high frequency lighting device. Inserted between the bulb and the induction coil, a slit that is approximately perpendicular to the winding direction of the induction coil is provided in a part of the metal tubular body, and this slit is installed in the bulb in which the discharge gas is sealed. The high frequency electromagnetic field generated from the induction coil is controlled.

According to the second aspect of the present invention, the number of slits provided in the portion of the metal tubular body facing the valve in the direction substantially perpendicular to the winding direction of the induction coil is 4 or more, and the number of slits is 4 or more. , Control the high frequency electromagnetic field generated from the induction coil installed in the bulb filled with the discharge gas. According to the invention of claim 3, one or a plurality of holes are provided in a portion of the metal tubular body facing the bulb, and the high frequency electromagnetic wave generated from the induction coil installed in the bulb filled with the discharge gas is formed by the holes. Control the world.

In the invention of claim 4, the metal tubular body has an opening at the back side of the hollow of the valve and the other end is closed, and approaches the valve near the closed end of the metal tubular body. One or more holes are provided at the location where the high frequency electromagnetic field generated from the induction coil installed in the bulb in which the discharge gas is sealed is controlled. According to a fifth aspect of the present invention, a part of the induction coil on the high potential side is brought into contact with the bulb through the hole of the metal cylindrical body, so that the high frequency electromagnetic field generated from the induction coil installed inside the bulb in which the discharge gas is sealed. To control.

In a sixth aspect of the present invention, a part of the induction coil on the high potential side is brought into contact with the valve through a hole provided in the valve sealing portion to generate a discharge gas from the induction coil installed in the valve. Control high frequency electromagnetic fields. In the invention of claim 7, the metal tubular body and the induction coil have the same potential as the ground side of the lighting device in terms of high frequency, and the winding start of the induction coil on the ground potential side is positioned near the opening of the metal tubular body. This controls the high-frequency electromagnetic field generated from the induction coil installed in the bulb filled with the discharge gas.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic front view of an electrodeless low-pressure discharge lamp according to the present invention with a part cut away. FIG.
13 will be described. The portions corresponding to those of FIG. 13 showing the conventional example will be described with the same reference numerals as those of FIG. 13. High frequency power flows from the lighting circuit 8 through the cable 7 to the matching circuit 6 in the base 5. A circuit that is matched to the induction coil 2 and the discharge lamp L at the time of lighting and starting is
It is set on the matching circuit 6. When high-frequency power flows from the matching circuit 6 to the induction coil 2, a high-frequency electromagnetic field is generated from the induction coil 2 and a discharge plasma 4 is formed in the bulb 1.

In the conventional electrodeless low-pressure discharge lamp (see FIG. 13), the ferrite 10 plays an important role in supplying the high-frequency electromagnetic field from the induction coil 2 to the discharge plasma 4. Ferrite 1
0 is enclosed in the valve 1 that generates heat, and the induction coil 2 and the ferrite 10 themselves generate heat, resulting in power loss. In particular, the power loss of the ferrite 10 increases as the temperature increases. So ferrite 1
The power loss is suppressed by using the copper rod heat pipe 11 (see FIG. 13) only for radiating 0.

When a high frequency electromagnetic field is applied to an air core coil which does not use the ferrite 10, power loss occurs due to internal resistance, and the internal resistance of the air core coil increases in resistance with temperature. When the resistance value increases, the power loss increases and the luminous flux decreases. In addition, when the discharge lamp L shifts to the lighting state, heat radiation from the bubble 1 itself starts, and the heat is conducted to the adjacent metal parts such as the induction coil 2, the ferrite 10 and the heat pipe 11 to cause power loss. This leads to a decrease in luminous flux.

Therefore, in the present invention, the air-core coil is used as the induction coil 2 without using the heat-generating ferrite 10 shown in FIG. 13 of the conventional example. Since the heat generation source is the air core coil (induction coil 2) and the discharge lamp L itself, a metal shield (metal cylinder 3) is inserted between the bulb 1 and the induction coil 2 as shown in FIG. To do. The metal shield is in a state of being in thermal contact with the heat radiation portion outside the discharge lamp L, and the heat of the induction coil 2 and the discharge lamp L is radiated from the heat radiation portion along the metal shield. As a result, the heat transferred from the discharge lamp L itself to the induction coil 2 is reduced, and the heat generated from the induction coil 2 itself is also reduced to lower the internal resistance of the induction coil 2. As a result, the power lost in the induction coil 2 decreases, the power transmitted to the discharge lamp L increases, and the luminous flux increases. Since the metal shield also has an effect of shielding a high-frequency electric field, it has an effect of suppressing a high-frequency electromagnetic field that causes the blackening of the phosphor 9, and extends the life of the lamp.

In the electrodeless low-pressure discharge lamp, several MH
When starting with a high-frequency discharge of z to several tens of MHz, glow discharge is first generated in the bulb 1 by high-frequency electric field discharge, and then arc discharge is generated by the high-frequency electromagnetic field to shift to a lighting state. When the metal of the metal tubular body 3 to be discharged is in the vicinity of the air-core coil (induction coil 3), that is, when a loop of metal or the like exists in the induction electric field direction of the high-frequency electromagnetic field, the high-frequency eddy current causes the loop-shaped metal When the discharge plasma 4 is not generated, such as when the discharge lamp L is started, the starting power may be combined with the metal near the induction coil 2 to make it difficult to start. Since the eddy current is generated in the loop-shaped metal shield, the metal cylinder 3
If the above is looped, there is a problem that an induction electric field is generated in the loop to consume power, power for starting cannot be supplied, and the luminous flux is damaged.

Therefore, in the present invention, although the metal tubular body 3 inserted between the induction coil 2 and the valve 1 also serves as a heat radiation function, as shown in FIG. Is provided with a slit 3a in a substantially right angle direction, the loop of the conductor generated from the induction coil 2 in the metal tubular body 3 is shielded by the slit 3a, and the coupling of the high-frequency electromagnetic field in the metal tubular body 3 is extremely high. There is an advantage that the high frequency electromagnetic field is supplied to the discharge plasma 4 to reduce the loss of the high frequency power supplied to the bulb 1 and the luminous flux is increased. Similarly, there is an advantage that the high frequency power applied at the time of starting is also low.

In the present invention, the electromagnetic field forms one loop, but the electromagnetic field generated from the induction coil 2 passes through the discharge plasma 4 in the bulb 1 and the induction coil 2
Come back to. Further, since the metal tubular body 3 enclosing the induction coil 2 has the same potential as the ground side 2b of the induction coil 2, the magnetic flux of the electromagnetic field is shielded to some extent, but the slit 3
A loop of magnetic flux leaks from the gap a and is coupled with the discharge plasma 4.

On the contrary, in order to positively let the magnetic flux pass, and in order to match the high-frequency electromagnetic field with the shape of the valve 1, a part of the metal cylindrical body 3 which is separated from the induction coil 2 is formed as shown in FIG. By providing the holes 3b in the, more magnetic flux can be passed. Therefore, the area for passing the magnetic flux is increased to increase the magnetic flux supplied to the discharge plasma 4, and the metal tubular body 3 that encloses the induction coil 2 in the loop of the magnetic flux.
By regulating the position of the hole 3b provided in the bulb 1, the discharge plasma 4 formed in the bulb 1 can be controlled to improve the lamp performance.

In addition, the induction electric field at the time of transition from electric field discharge to induction electric field discharge or during lighting plays an important role in the electrodeless low pressure discharge lamp. The induction electric field is naturally strong in the vicinity of the induction coil 2, and even in high-frequency discharge, the distribution of the discharge plasma 4 during lighting is determined by the relative position between the bulb 1 and the induction coil 2, and the discharge plasma 4 that matches the shape of the bulb 1 is generated. Forming is a fairly difficult technique.

In the electrodeless low pressure discharge lamp, the electromagnetic field spreads in the vertical and horizontal directions in the vicinity of the induction coil 2. Therefore, it is also generated in the openings at both ends of the metal tubular body 3. Since one end of the metal tubular body 3 faces the bulb 1, it is directly coupled to the discharge plasma 4 in the bulb 1. However, the other end of the metal tubular body 3 connects the metal tubular body 3 and the bulb 1 to each other. It is connected to the space of the base 5 that supports and houses the matching circuit 6. The high frequency electromagnetic field generated from the induction coil 2 is the base 5
Spread inside the. Therefore, one end of the metal tubular body 3 has a closed structure except for the hole through which the lead-in wire of the induction coil 2 is passed, and more high frequency electromagnetic fields generated from the induction coil 2 can be supplied to the discharge plasma 4.

For high-frequency discharge starting of the electrodeless low-pressure discharge lamp, when a metal plate having the same potential as the ground side of the lighting circuit 8 is inserted between the induction coil 2 and the bulb 1 containing the discharge plasma 4, There is a problem that the generated high frequency electric field is shielded and it is difficult to shift to electric field discharge. Further, since the starting of the electrodeless low-pressure discharge lamp needs to be performed by generating excited electrons in the bulb 1 in which almost no excited electrons exist, a high electromagnetic field is required.

Therefore, in the present invention, a part of the lead-in wire on the high potential side 2a of the induction coil 2 is provided with a hole 3 formed in the metal tubular body 3.
Contact valve 1 through b. In this way, a high-frequency high electromagnetic field is generated between the lead-in wire on the high potential side 2a of the induction coil 2 and the metal cylindrical body 3 in the vicinity that is grounded at high frequency, and the discharge plasma 4 is generated in the bulb 1. Is easily generated. Further, it is branched from the lead-in wire on the high potential side 2a of the induction coil 2, and one end of the wire is brought into contact with the lamp sealing portion. Similarly, a grounded metal tubular body 3 in the vicinity
A high electromagnetic field is formed between them and the startability is improved. Generally, the lamp-sealed portion is a portion to which the phosphor 9 is difficult to be applied, but it is possible to prevent blackening of the phosphor 9 in this portion.
Further, the same effect can be obtained by bringing the high potential side 2a of the induction coil 2 into contact with the portion where the phosphor 9 is not applied.

In the electrodeless low-pressure discharge lamp, the induction discharge forms a discharge loop in the bulb 1 and forms discharge plasma 4 at a certain distance from the tube wall coated with the phosphor 9, but a high-frequency high electric field. The discharge is performed by the phosphor 9 in the bulb 1 near the induction coil 2 that supplies a high frequency and high electric field.
However, there is also a problem that the phosphor 9 is blackened, which shortens the life of the lamp.

In the present invention, the high frequency electromagnetic field is generated by the induction coil 2.
Is formed between the high potential side 2a and the grounded metal in the vicinity thereof. The winding end of the induction coil 2 is located at one open end of the metal tubular body 3 that encloses the induction coil 2. This is because the valve 1 and the induction coil 2 are located close to each other, and by utilizing the property that the strength of the high frequency electromagnetic field is inversely proportional to the distance, the end of winding, which is the high potential side 2a of the discharge plasma 4, is formed into the metal tubular body 3. Of the induction coil 2 and the grounding side 2b of the winding end of the induction coil 2 is arranged closer to the bottom of the recess k of the valve 1. Thus, the loss of the high frequency electromagnetic field can be prevented, and the blackening of the phosphor 9 due to the high frequency electromagnetic field can be suppressed by the grounded cylindrical metal plate 3 to extend the lamp life.

(Example 1) 13.56 MHz was used as the frequency of the above-mentioned high frequency power. The bulb 1 is made of translucent glass and can be lit by inductive discharge, and has a shape close to a sphere with a diameter of 105 mm. Example 1
(See FIG. 1) specifically describes the invention of claim 1, and FIG. 3 shows a schematic front view with a part cut away. The metal tubular body 3 has a recess k at one location. The depression k has a cylindrical shape, and the depth of the depression k is about 70 mm in a straight line portion and about 37 mm in width. An exhaust pipe (not shown) extends from the center of the bottom of the recess k to the outer surface of the valve 1 around the center axis of the metal tubular body 3. An amalgam is placed in the middle of the exhaust pipe. A phosphor 9 is applied to the inner surface of the bulb 1. The discharge gas is filled with mercury gas and argon (Ar) of several tens to several hundreds of Pa. As the discharge gas, Kr, Ne, He, Xe or the like may be used instead of Ar.

The phosphor 9 and the film of the discharge area of the bulb 1 are determined by the wavelength at which the discharge plasma 4 is excited and emitted, and their volume occupies a small proportion in the discharge space. But there is no problem. For the induction coil 2, a copper wire is silver-plated and a wire which is insulation-coated with Teflon is used. The diameter of copper wire is 1.
6 mm, Teflon insulation coating 0.3 m
m. The number of turns of the induction coil 2 is 9.5 turns, and the induction coil 2 is closely wound to an outer diameter of 32 mm, and the inductance of the induction coil 2 when there is no load is about 1.6 μH. Although the number of turns of the induction coil 2 may be large or small, both of the feeder lines of the induction coil 2 are connected to the matching circuit 6. Although the metal tubular body 3 is made of an aluminum material, any material having good dischargeability and conductivity may be used.

From the vicinity of the induction coil 2 to the depression k of the valve 1.
A slit 3a is provided in a portion in contact with the inner surface of the induction coil 2 in a direction perpendicular to the winding direction of the induction coil 2, that is, in a direction parallel to the central axis of the induction coil 2. Actually, the slit 3a having a groove width of 1 mm and having a length of 60 mm from the recess k side of the valve 1 was used. The slits k were arranged at equal intervals according to the number. The number of slits k may be two or more, but the larger the number, the easier the starting and the more luminous flux.

The metal tubular body 3 is connected to the base 5 enclosing the matching circuit 6, and the heat of the metal tubular body 3 is radiated from the surface of the base 5. It goes without saying that the metal tubular body 3 and the base 5 are designed to have good heat conduction. The material of the base 5 has good thermal conductivity, and is, for example, aluminum, copper, ceramic or the like. (Embodiment 2) Embodiment 2 (see FIG. 1) specifically explains the invention of claim 2, and shows an example in which the number of slits k is increased. FIG. 2 shows the number of slits and the luminous flux. The relative ratio is shown. It is assumed that the induction coil 2 has 9.5 turns and the matching state of the input power of the matching circuit 6 at the time of lighting is the same. The luminous flux increases as the number of slits 3a increases. However, the number of slits 3a is 4
If the number is equal to or more than the number of lines, the increase in the luminous flux is not so great, and the increase rate is several percent.

(Embodiment 3) Embodiment 3 (see FIG. 3) is for specifically explaining the invention of claim 3, and FIG. 3 is a partially cutaway schematic front view. Holes, slits, and round holes are provided in the metal tubular body 3, but actually, as shown in FIG. 3, four round holes 3b having a diameter of 16 mm are provided at positions 60 mm lower than the top of the metal tubular body 3. It was The effect is
As shown in Table 1, comparing the case where only the slit is provided and the case where the round hole is provided, the absolute value of the luminous flux when the circular hole is provided is about 10% of the absolute value of the luminous flux of only the slit. You can see that it has increased.

[0035]

[Table 1]

(Embodiment 4) Embodiment 4 (see FIG. 4) is for specifically explaining the invention of claim 4, and FIG. 4 is a partially cutaway schematic front view. A hole and a square hole are provided in the metal tubular body 1. Actually, as shown in FIG. 4, the induction coil 2
A square hole 3c was provided as much as possible in a portion where only the slit was inserted in the wound portion and the cylindrical metal plate 3 and the induction coil 2 were not in contact with each other. As shown in Table 1 above, it can be seen that even if the induction coil 2 is the same, the luminous flux is increased by about 10% as compared with the case where only the slit is provided.

(Embodiment 5) Embodiment 5 (see FIG. 5) is for concretely explaining the invention of claim 5, and FIG. 5 shows a partially cutaway schematic front view. It controls the hole h at the opening of the body 3, and by changing the size of the hole h at one end of the metal tubular body 3 close to the depression k of the bulb 1, the brightness of the top of the bulb 1 becomes higher. It was

(Embodiment 6) Embodiment 6 (see FIG. 6) is for concretely explaining the invention of claim 6, and FIG. 6 shows a partially cutaway schematic front view. One end S of body 3
By blocking and reducing the area of the hole h of the opening of the metal tubular body 3, the brightness of the top of the bulb 1 increased and the luminous flux increased overall.

(Embodiment 7) Embodiment 7 (see FIG. 7) is for specifically explaining the invention of claim 7, and FIG. 7 shows a partially cutaway schematic front view. Is wound and a hole O having a diameter of several mm is formed in a portion in contact with the metal tubular body 3. When there is no hole, the high potential side 2 of the induction coil 2
If a is arranged at the bottom of the depression k of the valve 1, an electric power of about 100 W is required, but if the hole O is simply provided, it is about 20.
The discharge plasma 4 was formed by W.

(Embodiment 8) Embodiment 8 (see FIG. 8) is to specifically explain the invention of claim 7 as another example, and FIG. 9 shows a partially cutaway schematic front view. , Two holes a and a are provided in a portion where the metal tubular body 3 faces the valve 1, and a slit is provided between the two holes a and a to form the induction coil 2 from the inside of the metal tubular body 3 in the two holes a and a. Through the line on the high potential side 2a, the same effect as in the case of Example 7 was obtained.

(Embodiment 9) Embodiment 9 (see FIG. 9) is to concretely explain the invention of claim 7 as another example. FIG. 9 shows a partially cutaway schematic front view. However, a wire is branched from the high potential side 2a of the induction coil 2 and one end of the branch is brought into contact with a part of the valve 1 through a hole P provided in the base 5, and the same effect as in the case of the seventh embodiment is obtained. was gotten.

(Embodiment 10) Embodiment 10 (see FIG. 10)
10 specifically illustrates the invention of claim 7 as another example, and FIG. 10 shows a schematic front view in which a part is cut away. The high potential side 2a and the ground side 2b of the induction coil 2 are shown in FIG. Were brought close to each other and the portion thereof was brought into contact with a part of the exhaust pipe P, and the same effect as in the case of Example 7 was obtained.

(Embodiment 11) Embodiment 11 specifically describes the invention of claim 7 as still another example, and FIG. 11 shows a partially cutaway schematic front view.
The winding end side of the induction coil 2 closer to the bottom of the depression k of the bulb 1 was set to have the same potential as the ground side 2b of the lighting circuit 8 in terms of AC. When the light is turned on in this state, the blackening of the phosphor 9 is gradually reduced and the life is extended.

As described in each of the above embodiments, by providing the slits 3a, 3b, the square holes 3c, etc. in the metal tubular body 3, the magnetic flux generated by the induction coil 2 can easily pass through the metal tubular body 3. Then, the magnetic flux path is controlled. 12 is a graph showing the relationship between the shape and the number of slits 3a or holes 3b, 3c provided in the metal tubular body 3 of the electrodeless low-pressure discharge lamp L and the luminous flux ratio.

[0045]

The electrodeless low-pressure discharge lamp according to the present invention has the following effects. That is, in the invention of claim 1, an induction coil is provided in the recess of the bulb, and a metal tubular body having good thermal conductivity and having an opening on the back side of the recess of the bulb having the same potential as the ground side of the high-frequency lighting device, Inserted between the valve and the induction coil, a slit that is approximately perpendicular to the winding direction of the induction coil is provided in a part of the metal tubular body, and the slit allows the discharge gas to be installed in the bulb. By controlling the high-frequency electromagnetic field generated from the coil, there is an advantage that the startability, luminous flux and lamp life of the discharge lamp can be remarkably improved.

According to the second aspect of the present invention, the number of slits provided in the portion of the metal tubular body facing the valve in the direction substantially perpendicular to the winding direction of the induction coil is four or more, and the slits of four or more are provided. By controlling the high-frequency electromagnetic field generated from the induction coil installed in the bulb in which the discharge gas is sealed, the startability, luminous flux, and lamp life of the discharge lamp can be remarkably improved.

According to the third aspect of the invention, one or a plurality of holes are provided at the portion of the metal tubular body facing the valve,
By controlling the high frequency electromagnetic field generated from the induction coil installed in the bulb in which the discharge gas is sealed by this hole, there is an advantage that the startability, luminous flux and lamp life of the discharge lamp can be remarkably improved. In the invention of claim 4, the metal tubular body has an opening at the inner side of the recess of the valve and the other end is closed, and the portion close to the valve near the closed end of the metal tubular body. In addition, by providing one or more holes and controlling the high frequency electromagnetic field generated from the induction coil installed in the bulb filled with the discharge gas, the startability, luminous flux and lamp life of the discharge lamp can be controlled. There is an advantage that it can be significantly improved.

In the invention of claim 5, a part of the high potential side of the induction coil is generated from the induction coil installed in the bulb in which the discharge gas is enclosed by contacting the bulb through the hole of the metal cylindrical body. By controlling the high-frequency electromagnetic field, there is an advantage that the startability, luminous flux and lamp life of the discharge lamp can be remarkably improved. According to the invention of claim 6, a high-frequency electromagnetic field generated from the induction coil, which is installed in the bulb in which the discharge gas is sealed, by bringing a part of the high potential side of the induction coil into contact with the valve through a hole provided in the valve sealing portion. By controlling the above, there is an advantage that the startability of the discharge lamp, the luminous flux and the lamp life can be remarkably improved.

According to the invention of claim 7, the metal tubular body and the induction coil have the same potential as the ground side of the lighting device in terms of high frequency, and the beginning of winding on the ground potential side of the induction coil is near the opening of the metal tubular body. By controlling the high frequency electromagnetic field generated from the induction coil installed in the bulb in which the discharge gas is sealed, the startability, luminous flux and lamp life of the discharge lamp can be significantly improved.

[Brief description of drawings]

FIG. 1 is a first embodiment of an electrodeless low pressure discharge lamp according to the present invention.
FIG. 3 is a schematic front view of a partially cutaway view showing Embodiment 2 and Embodiment 2.

FIG. 2 is a graph showing the number of slits and the relative ratio of luminous flux.

FIG. 3 is a third example of the electrodeless low-pressure discharge lamp according to the present invention.
FIG. 3B is a schematic front view of a partially cutaway view.

FIG. 4 is a fourth example of the electrodeless low-pressure discharge lamp according to the present invention.
FIG. 3B is a schematic front view of a partially cutaway view.

FIG. 5 is a fifth embodiment of an electrodeless low pressure discharge lamp according to the present invention.
FIG. 3B is a schematic front view of a partially cutaway view.

FIG. 6 is a sixth embodiment of an electrodeless low pressure discharge lamp according to the present invention.
FIG. 3B is a schematic front view of a partially cutaway view.

FIG. 7 is a seventh embodiment of an electrodeless low pressure discharge lamp according to the present invention.
FIG. 3B is a schematic front view of a partially cutaway view.

FIG. 8: Example 8 of electrodeless low-pressure discharge lamp according to the present invention
FIG. 3B is a schematic front view of a partially cutaway view.

FIG. 9 is a ninth embodiment of an electrodeless low pressure discharge lamp according to the present invention.
FIG. 3B is a schematic front view of a partially cutaway view.

FIG. 10 shows Example 10 of the electrodeless low pressure discharge lamp according to the present invention, and is a schematic front view of a partially cutaway one.

FIG. 11 shows Example 11 of the electrodeless low pressure discharge lamp according to the present invention, and is a schematic front view of a partially cutaway one.

FIG. 12 is a graph showing the relationship between the shape and the number of slits or holes provided in the metal tubular body of the electrodeless low-pressure discharge lamp and the luminous flux ratio.

FIG. 13 is a sectional front view showing an example of a conventional electrodeless low-pressure discharge lamp.

[Explanation of symbols]

 1 Valve 2 Induction Coil 3 Metal Cylindrical Body 3a Slit 4 Discharge Plasma 5 Base 6 Matching Circuit 7 Cable 8 Lighting Circuit 9 Phosphor k Recess

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Hiramatsu 1048, Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works Co., Ltd. (72) Shigeki Matsuo, 1048, Kadoma, Kadoma City, Osaka Matsushita Electric Works Co., Ltd.

Claims (7)

[Claims] 1. A fluorescent material is applied to an inner wall of a discharge space inside a bulb, which is made of a translucent material and in which a discharge gas is sealed, and a high frequency power is supplied to an induction coil to generate a high frequency electromagnetic field to excite the discharge gas. In an electrodeless low-pressure discharge lamp that emits light and emits light from a phosphor, the bulb has a recess, and an induction coil is provided in the recess of the bulb to have good thermal conductivity and A metal tubular body having an opening at the back side of the hollow of the valve having the same potential as the ground side is inserted between the valve and the induction coil, and a part of the metal tubular body is wound with the winding direction of the induction coil. An electrodeless low-pressure discharge lamp characterized by having slits that are substantially vertical. 2. The number of slits provided in the portion of the metal tubular body facing the valve in a direction substantially perpendicular to the winding direction of the induction coil is four or more. Electrodeless low pressure discharge lamp. 3. The electrodeless low-pressure discharge lamp according to claim 2, wherein one or a plurality of holes are provided in a portion of the metal tubular body facing the bulb. 4. The metal tubular body has an opening at the inner side of the hollow of the valve and the other end is closed, and the metal tubular body is close to the valve near the closed end, The electrodeless low pressure discharge lamp according to claim 2 or 3, wherein one or more holes are provided. 5. The electrodeless low-pressure discharge lamp according to claim 2, wherein a part of the induction coil on the high potential side is in contact with the bulb through the hole of the metal cylindrical body. 6. The electrodeless low-pressure discharge lamp according to claim 2 or 3, wherein a part of the induction coil on the high potential side is in contact with the high-potential side through a hole provided in the bulb sealing portion. 7. The metal tubular body and the induction coil have the same potential as the ground side of the lighting device in terms of high frequency, and the winding start on the ground potential side of the induction coil is located near the opening of the metal tubular body. Claims 2, 3, 4, 5 characterized by
Alternatively, the electrodeless low-pressure discharge lamp according to claim 6.