WO2001088952A1

WO2001088952A1 - Electrodeless discharge lamp

Info

Publication number: WO2001088952A1
Application number: PCT/JP2001/003969
Authority: WO
Inventors: Robert Chandler; Oleg Popov; Jakob Maya; Edward Shapiro
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2000-05-12
Filing date: 2001-05-11
Publication date: 2001-11-22
Also published as: TW492046B; JP2001325920A

Abstract

An electrodeless discharge lamp with high lamp efficiency. The electrodeless discharge lamp (100) comprises an envelope (1) having a discharge gas filled therein, a coil (8) producing an electromagnetic field in the envelop (1), and a raised portion formed in the envelope (1) and projecting outward of the envelope (1). The tube wall load of the electrodeless discharge lamp (100) is not less than 0.05 W/cm2. The envelop (1) has a recess cavity (2) and the coil (8) may be disposed in the recess cavity (2).

Description

Description Electrodeless discharge lamp Technical field

The present invention relates to air lamps, and more particularly to electrodeless fluorescent lamps that operate at frequencies between 50 kHz and 1 MHz and at low or intermediate pressures. Background technology ''

Electrodeless fluorescent lamps operating at frequencies in the range of tens of kHz to tens of MHz have a longer life than conventional fluorescent lamps having internal electrodes and heating filaments. Recently, General Electric Corp. introduced an electrodeless miniature fluorescent lamp mainly for indoor use ("Genura"). This lamp has a light output of 1100 lumens at a total power of 23 W and a long life of 15,000 hours. In order to provide high lamp light output at low and high ambient temperatures, the lamp must be close to approximately 6 mTorr (approximately 798 mPa) within a wide range of amalgam, from about 70 ° C to about 120 ° C. Utilize bismuth amalgam to maintain optimal mercury vapor pressure.

The disadvantage of this lamp is that the rise time of the lamp, the time required to reach 50% of the lamp's maximum light output, is relatively long. The rise time of the G enura lamp is longer than 80 seconds. The longer rise time is due to the relatively long time (about 1 minute) required to heat the amalgam to the required temperature of about 70 ° C.

In fact, to provide a high mercury vapor pressure of 3-4 mTo rr (399-532 mPa), sufficient to produce a high light output corresponding to 70-80% of the maximum light output obtained at 6 mTo rr The amalgam must be at a temperature of 70 ° C. Sudden In order to achieve rapid heating of the amalgam, the prior art has placed amalgam in different parts of the lamp envelope (US Pat. No. 5,412,288 to Borowiec et al., US Pat. No. 5,412,289, U.S. Pat. No. 5,434,482 to Bourowiec et al. And U.S. Pat. No. 5,789,855 to Forsdyke et al.). In some cases, the supplemental amalgam was placed in a flag (see, for example, Maya et al., US Pat. No. 5,698,951; Cocoma et al., US Pat. No. 5,783,912, Borowiec). U.S. Pat. No. 5,841,229), or the vacuum side of a concave cavity wall heated directly by a discharge plasma (Wah rmby et al., U.S. Pat. No. 5,767,617; Forsdyke et al.). U.S. Pat. No. 5,789,855). However, using more than one amalgam did not reduce the rise time to less than 80 seconds.

In U.S. patent application Ser. No. 09Z435,968, filed Nov. 8, 1999, which is the same assignee as the application on which the priority is based, we have found that at relatively low RF frequencies of 100 kHz, An operating electrodeless miniature fluorescent lamp has been described. The use of ferrite cores and low-resistance ripwires provides low coil / core power loss, and this low coil Z core power loss results in high power efficiency for the lamp when amalgam is placed in the tubule8) High maximum lamp efficiency was obtained.

The rise time of this lamp was rather long (= lmin) and corresponded to the rise time of the Genura lamp. To shorten the rise time, we used pure mercury drops instead of amalgam.

However, in the lamp described above and having the shape described in the patent application by the present inventors and operating with "pure" mercury droplets without using amalgam, the lamp operates stably on the surface of the lamp. No point could have a temperature below 70 ° C. As a result, the pressure of the mercury droplet during stable operation was higher than 6 mTorr, and the stable light output was as low as about 75 to 80% of the maximum light output. It is an object of the present invention to operate at a frequency of about 100 kHz and an inductively coupled power of about 23 W, not to be larger than a standard incandescent lamp, and to have a size of about 160 to 1 The objective is to design a compact electrodeless fluorescent lamp that produces visible light with a maximum output of 650 lumens.

It is another object of the present invention to control the mercury vapor pressure during lamp operation with the base up and base down, providing a stable equivalent of about 90% of the maximum light output of 165 lumens. It is to provide the coldest point that results in light output.

It is a further object of the present invention to provide a cooling structure that maintains the temperature of a ferrite core below its Curie point.

It is yet another object of the present invention to provide an enclosure for drivers and matching circuits inside a cooling structure.

It is a further object of the present invention to provide a cooling structure which keeps the temperature inside the ceramic enclosure in which the dry and matching circuits are arranged low (T <100 ° C.). '

Another object of the present invention is to provide a 100 W power supply with much higher efficiency and a 5 to 10 times longer lifespan than an incandescent light bulb while having dimensions comparable to an incandescent light bulb. An object of the present invention is to provide a compact fluorescent lamp that can directly replace an incandescent light bulb. Disclosure of the invention

An electrodeless discharge lamp according to the present invention includes an envelope filled with a discharge gas, a coil that generates an electromagnetic field in the envelope, and a protrusion formed on the envelope and protruding toward the outside of the envelope. And the tube wall load is 0.05 WZ cm ² or more, whereby the object is achieved.

The envelope may have a concave cavity, and the coil may be disposed inside the concave cavity.

The electrodeless discharge lamp further includes a ferrite core, and the coil includes: It may be wound around a ferrite core.

The maximum thickness, the minimum and the thickness of the envelope at the raised portion are both

0.1 mm or more and 2 mm or less.

The height of the ridge may be less than 7 mm.

Another electrodeless discharge lamp of the present invention includes an envelope filled with a discharge gas, a coil that generates an electromagnetic field in the envelope, and a protrusion formed on the envelope and protruding toward the outside of the envelope. The coil has an inductive coupling power frequency of 50 kHz or more and 1 MHz or less, thereby achieving the above object.

The tube wall load of the electrodeless discharge lamp may be 0.05 WZ cm ² or more. The envelope may have a concave cavity, and the coil may be disposed inside the concave cavity.

The electrodeless discharge lamp may further include a ferrite core, and the coil may be wound around the ferrite core.

The maximum thickness and the minimum thickness of the envelope at the raised portion are both

It may be 0.1 mm or more and 2 mm or less.

The height of the ridge may be less than 7 mm.

Another electrodeless discharge lamp according to the present invention includes an envelope filled with a discharge gas therein, and a coil that generates an electromagnetic field in the envelope, wherein the envelope has a side wall and a top, and the side wall. The radius of curvature of the corner formed by the top and the top is 10 mm or less, thereby achieving the above object.

The present invention encompasses an electrodeless fluorescent lamp including a glass envelope containing a fill of an inert gas containing mercury vapor. The top of the envelope has a small thin glass dome that acts as the cold spot for mercury vapor when the lamp is lit "base up". Glass "skirt" with a gap of a few mm Sealed to the bottom edge of the force envelope. This glass “skirt” It is likely to provide the coldest point when it lights up with its “down” position. A ferrite core and a coil formed from the Ritzwire are placed in the recess cavity. The cooling structure includes a metal (aluminum, copper) tube disposed inside the magnetic core and a ceramic enclosure adhered to the metal tube and the Edison socket with a material having high thermal conductivity. A power driver and matching circuit are located inside the ceramic enclosure and receive power from the main power supply via an Edison socket. Brief description of the drawings ''

FIG. 1 is a cross-sectional view of a first embodiment of the present invention, showing an electrodeless compact fluorescent lamp that operates in a base-up position and a base-down position.

FIG. 2 is a view showing an electrodeless fluorescent lamp which is a variation of Embodiment 1 of the present invention in which a skirt is removed for a simpler manufacturing process.

3A to 3C are diagrams showing a modification of a thin glass dome on a spherical envelop in which the coldest point for controlling the mercury vapor pressure is formed.

4A to 4D show an annular ridge scart that can be placed on the top, bottom, or sides of the glass envelope.

5A to 5C are schematic diagrams of modified examples of the coldest corner formed by the top and side walls of the envelope that can be used in the electrodeless fluorescent lamp according to the second embodiment of the present invention. . BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1)

FIG. 1 shows an electrodeless fluorescent lamp 100 according to Embodiment 1 of the present invention. Referring to FIG. 1, a glass spherical envelope 1 has a recessed cavity 2 and an exhaust capillary 3 located on its axis inside the cavity 2. Inside Envelope 1, As the discharge gas, a mixed gas of an inert filling gas (eg, argon, krypton, etc.) and mercury vapor is sealed. The inert fill gas is at a pressure of 50 mT orr to 5 T orr (665 OmPa to 665 Pa). In the electrodeless fluorescent lamp 100, the diameter and height of the envelope are 5 O mm and 65 mm, respectively. The concave cavity 2 is recessed from the outside of the envelope 1 toward the inside.

The mercury pressure in envelope 1 is maintained by the temperature of the coldest spot on the envelope surface. After several hours of operation, mercury drops condense to this cold spot. In a lamp operating with the base down, the coldest point lies in the gap formed by the inner wall 5 and the outer wall 6 of the skirt 4 (first ridge). After several hours of lamp operation, mercury vapor condenses at the bottom of the gap, which becomes the coldest point of the envelope and controls the mercury vapor pressure. In a preferred embodiment, the length of the skirt is 25 mm and its inner and outer diameters are 40 mm and 45 mm, respectively. With the base up, the coldest spot in the lamp is on the inner surface of the thin glass dome 7. In a preferred embodiment, the dome (second ridge) 7 is provided on a spherical top as shown in FIG. The height h of the dome 7 is 5 mm, the diameter d at the bottom of the dome 7 is about 9 mm, and the thickness of the glass is about 0.3 mm.

The present inventors have found that when the diameter at the bottom of the dome 7 is smaller than about 8 mm, the effect of improving the light output is reduced. This is because if the diameter at the bottom of the dome 7 is small, it becomes extremely difficult for the discharge gas in the envelope 1 to enter the dome 7 by convection, and as a result, the function of controlling the mercury vapor pressure This is due to a decrease in On the contrary, the present inventors have also found that even when the diameter at the bottom of the dome 7 is extremely large, the effect of improving the light output is still small. This is because the discharge gas intrusion due to convection becomes excessive, and the heat inflow thereby increases, so that the temperature at the coldest point rises. Dome 7 has a bottom diameter of 15 mm If it becomes larger, the effect of improving the light output becomes smaller.

In the present specification, the raised portion is a portion where the curvature of the envelope 1 changes from negative to positive to negative along at least one cross section of the envelope 1, and at that portion, the envelope 1 However, this is where the electrodeless fluorescent lamp is in contact with the outside. Here, it is assumed that the curvature of the envelope 1 is positive when it is convex toward the outside of the envelope 1 and negative when it is convex toward the inside of the envelope 1. For example, at the dome 7 shown in FIG. 1, the curvature of the envelope 1 changes from negative (part 101) to positive (part 102) to negative (part 103). This change in the curvature of Envelope 1 means that the ridge protrudes outward from Envelope 1. Since the envelope 1 is in contact with the outside (ambient atmosphere) of the electrodeless fluorescent lamp at the raised portion, the contact area between the envelope 1 and the surrounding atmosphere is increased as compared with the case where no raised portion is provided. This lowers the temperature of the ridge and the temperature at the coldest point is low enough to provide the required stable light output.

A coil 8 formed from a plurality of strand wires (Litz wires) is wound around a ferrite core 9. In a preferred embodiment, the wire has 66 insulated coated strands, each of which is # 40 gauge. The coil has two layers with a total of 65 turns. The hollow I-shaped ferrite core 9 is formed from a MnZn material (see US Patent Application No. 09-3, filed May 3, 1999 by Chamber 1 ain et al.). No. 0,3,951, and U.S. Patent Application No. 0,934,5,960 filed on Jan. 9, 1999 by C handler et al. It is located in the recessed cavity 2). In a preferred embodiment, the ferrite core has a diameter of 15 mm and a length of 55 mm.

Since the coil 8 is wound around the ferrite core 9, the inductance of the coil / ferrite core is larger than the inductance of the coil 8 alone. Become. Thereby, the luminous efficiency of the electrodeless fluorescent lamp 100 is increased.

The coil 8 and the ferrite core 9 are maintained at a temperature below the Curie point (<220 ° C) by the cooling structure including the metal tube 10 and the ceramic enclosure 11. Tube 10 is formed of metal (copper) having high thermal conductivity and low induced power loss. The ceramic enclosure 11 is formed from several alumina parts integrally bonded with a material having high thermal conductivity. The ceramic enclosure 11 may also be formed from a single piece. The ceramic enclosure 11 is bonded to a copper plate 12 welded to an Edison socket 13. In a preferred embodiment, the thickness of the wall of the ceramic enclosure is 4 mm.

Two ceramic spacers 14 and 15 are inserted inside the ferrite core 9 to prevent the tube 10 from extending outside the core, thereby reducing power loss in the copper tube 10. 'In a preferred embodiment, the length of the ceramic spacers 14 and 15 is 5 mm. A matching circuit and driver (not shown) are located in the ceramic enclosure 11 on the PC board 16. The position of the PC pod 16 is selected so that the temperature of the driver components does not exceed 100 ° C. The main power supply is connected to the driver via Edison socket 13.

The heat generated by the plasma and the induced power (= 3 to 4 W) absorbed in the ferrite core 9 is sent to the Edison socket 13 via the copper tube 10 and the ceramic enclosure 11. And then sent to a lamp holder (not shown). Some of the heat is dissipated by convection through the ceramic enclosure 11 and the outer surface 6 of the glass container 4. As a result, when the ambient temperature is 25 ° C and the inductive coupling power is 23 W, the temperature inside the ceramic enclosure 11 where the PC pod 16 is placed is 100 ° C. Do not exceed.

The inner surface of the envelope 1 including the inner surface of the skirt 4 is covered with a protective coating 17 and a phosphor coating 18. Reflective coating 1 9 (Alumina Etc.) are applied on the inner surface of the cavity 9 '. The outer wall of the cavity 2 adjacent to the coil 8 is covered with a reflective coating 20 (alumina, etc.) to reduce the amount of visible light passing through the inner cavity wall 2.

The electrodeless fluorescent lamp 100 can be used in a base up position, a base down position, and a horizontal position.

FIG. 2 shows an electrodeless fluorescent lamp 200 which is a variation of the first embodiment of the present invention. In FIG. 2, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. The electrodeless fluorescent lamp 2000 has an envelope 1, a cavity 2, a coil 8, and a ferrite core 9 as in the electrodeless fluorescent lamp 100, but does not have a glass skirt 4. The electrodeless compact fluorescent lamp 200 can be used for lamp-up lighting when the coldest point is on the inner surface of the thin glass dome 7.

Various modifications of the thin glass bulge that functions as the coldest point are shown schematically in FIGS. 3A-3C. 3A to 3C show the shapes of the envelopes 22 that can be used in place of the envelopes 1 of the electrodeless fluorescent lamp 100 (FIG. 1) and the electrodeless fluorescent lamp 200 (FIG. 2). Show some.

The glass bulge shown in FIG. 3A has a wedge shape 21 and is provided at the top of the envelope 22. Another type of glass ridge that serves as the coldest point is shown in FIGS. 3B and 3C. One ridge has a shape of 拄 23, and the other has a shape of a sphere 24. A deep annular depression 25 separates the ridge from the hot walls of the envelope and reduces the temperature of the ridge by improving contact with the surrounding atmosphere.

4A to 4D show the shapes of the envelope 34 that can be used in place of the envelope 1 of the electrodeless fluorescent lamp 100 (FIG. 1) and the electrodeless fluorescent lamp 200 (FIG. 2). Show. As shown in FIGS. 4A to 4D, the coldest point ridge has the shape of an annular ridge 32 having an annular gap 33 where the coldest point is formed. Figure 4 A and In FIG. 4B, an annular ridge is provided at the top of the envelope 34. Ridges 32 with gaps 33 can be provided on the bottom and side walls of the envelope as well (FIGS. 4C and 4D).

The lamp operates as follows. Normal inert gas pressure (argon) is about 1 TO rr (about 133 Pa), and inductive coupling power frequency (frequency of alternating current applied to coil 8) is about 100 kHz. AC power from the main power supply (60 Hz) is supplied via the Edison socket 13 to a driver and a matching circuit (not shown) arranged on the PC board 16 in the ceramic enclosure 11. An induced voltage at a frequency of 100 kHz is applied to the coil 8 from the matching circuit. The coil current 1 c generates an induced magnetic field, and the generated induced magnetic field generates an RF azimuthal electric field E _z in the envelope. Thus, the coil 8 generates an electromagnetic field in the envelope. When the voltage V _e applied to the coil 8 reaches 200-300 V, the voltage V _c generates a capacitive discharge along the cavity wall 2 in the envelope.

If the induced (azimuthal) voltage V _pl induced in the lamp reaches a value sufficient to maintain the inductively coupled discharge in the envelope, the coil voltage (V _c ) and the coil current (I _c ) decreases. As a result, the reflected wave power _Pref decreases, and the plasma brightness sharply increases. The transition from capacitive discharge to inductive discharge is the lamp start

It is called (Danidanion). Result of increased power P _{l # 038} which is absorbed by the lamp, the light output is increased, the coil holding current 1 _m and the coil holding voltage V _m is reduced.

The light output of the _lamp depends not only on the power P _lamp, but also on the mercury vapor pressure which rises with a temperature of the coldest point 7 (lighting up the base) or 4 (lighting down the base). The maximum light output, ie the highest lamp efficiency, is reached when the coldest point temperature is around 44-55 ° C. A further increase in cold spot temperature results in an increase in mercury vapor pressure and a decrease in lamp brightness. Therefore, if the temperature on the surface is sufficiently low, the effect is not so great even if there are bumps. The temperature on the surface of the lamp depends on the lamp wall loading of the lamp. The present inventors found that the tube wall load of the lamp was 0.05 WZc It has been found that when it is not less than m ² , there is an effect of the ridge. When the lamp wall load is more than 0.07 cm ² , the effect of the ridge becomes very large. The tube wall load is defined as a value obtained by dividing the active power input to the coil 8 by the inner wall surface area of the envelope 1. The active power input to the coil 8 is measured, for example, by connecting a power meter to the input side of the matching circuit.

In the preferred embodiment (FIG. 1) and with the base up, the maximum lamp operating at 100 kHz frequency and 23 W (1630 lumens, 71 LPW) at base up position Light output is achieved when the temperature outside the thin glass dome 7 is 46-48 ° C. The lamp reaches a steady light output after 2 hours of continuous operation at 23W for 2 hours. The stable light output at 23 W was 1515 lumens (66 LPW), and the temperature at the coldest point 7 was 57-59 ° C. Thus, the stable light output of the lamp according to the invention corresponds to 93% of the maximum lamp light output of 1630 lumens. The electrodeless miniature fluorescent lamp without specially designed glass addenda (bulges) was found to have low stable light output, only 80-85% of the maximum light output. The tube wall load of this lamp was 0.1 lWZcm ² .

Rise measurements of lamps manufactured according to the present invention showed that within 2-3 seconds of starting the lamp, 50% of the maximum light output was reached. This rise time is shorter than the rise time of the conventional electrodeed fluorescent lamp.

The present inventors have discovered that the higher the height h of the glass dome 7, the lower its temperature and the higher the lamp light output. However, we have found that the glass dome 7, like the other ridges shown in FIGS.3A-3C and FIGS.4A-4D, is too large for aesthetic reasons and strength related reasons. It was found that the height h of the glass dome 7 was preferably less than 7 mm. The other ridges shown in FIGS. 3A-C and 4A-D are also preferably less than 7 mm. In addition, the inventors have determined that the temperature of the coldest point on the ridge must not be less than 40 ° C. I discovered that.

If the thickness of the envelope 1 at the ridge is too small, the strength of the ridge is reduced. If the thickness of the envelope 1 at the ridge is too large, the temperature at the coldest point cannot be lowered sufficiently. It is preferable that both the maximum thickness and the minimum thickness of the envelope 1 in the protruding portion are 0.1 mm or more and 2 mm or less. The inductively coupled power frequency of the electrodeless fluorescent lamp to which the present invention can be applied is not limited to 100 kHz. However, if the inductively coupled power frequency is too low, the electrodeless fluorescent lamp will not be easy to start, and if the inductively coupled power frequency is too high, the cost of the driver will be high, and it will be necessary to prevent electromagnetic interference (EMI). Costs are also high. In consideration of such a point, it is preferable that the inductive coupling power frequency of the electrodeless fluorescent lamp is 50 kHz or more and 1 MHz or less.

The ferrite core 9 can be omitted. However, when the electrodeless fluorescent lamp is driven at a relatively low inductive coupling power frequency such as 50 kHz or more and 1 MHz or less, the ferrite core 9 is preferably used. When an electrodeless fluorescent lamp is driven at a low inductively coupled power frequency, the induced voltage V _p 〖induced in the lamp is lower than when an electrodeless fluorescent lamp is driven at a higher inductively coupled power frequency. Is smaller, and this is compensated for by using the ferrite core 9. When the ferrite core 9 is used, when the electrodeless fluorescent lamp is driven, the heat generated by the loss (iron loss) in the ferrite core 9 increases in addition to the Joule heat of the coil 8. For this reason, the driven ferrite core 9 is cooled by the cooling structure including the metal tube 10 and the ceramic enclosure 11, but its temperature can rise to about 200 ° C. For lighting with the base up, the coldest point is the top of the lamp away from the plasma. As can be understood from FIG. 1, the top of the lamp is close to the top of the ferrite core 9 (near the ceramic spacer 14). Therefore, the top of the lamp is affected by the heat transfer from the ferrite core 9 and the temperature rises. Therefore, when the ferrite core 9 is used, In addition, it is preferable to provide a raised portion for providing the coldest point on the envelope 1. (Embodiment 2)

5A to 5C show shapes of an envelope 44 that can be used for the electrodeless fluorescent lamp according to the second embodiment of the present invention. The envelope 44 can be used in place of the envelope 1 of the electrodeless fluorescent lamp 100 (FIG. 1) of the first embodiment of the present invention. The electrodeless fluorescent lamp according to Embodiment 2 of the present invention has the same configuration as the electrodeless fluorescent lamp 100 except for the envelope 44. Therefore, the overall diagram is not shown. 5A to 5C, the exhaust tubing inside the concave cavity 2 is not shown. In FIGS. 5A-5C, the coldest point 43 is within the corner 42 formed by the top 46 and the side wall 45 of the envelope. As shown in FIG. 5 A, corner - _{4 2} of the curvature radius r is equal to or less than 1 0 mm, it has been found that the effect of lowering the temperature of the coldest spot 4 3 is obtained. When the radius of curvature r is 8 mm or less, the effect of lowering the temperature at the coldest point 43 is further increased, which is more preferable. When the inductive coupling power is increased, it is preferable to reduce the radius of curvature to obtain a desired effect.

Thus, the electrodeless fluorescent lamp of the second embodiment of the present invention is the same as the electrodeless fluorescent lamp of the first embodiment (the electrodeless fluorescent lamp 100 shown in FIG. 1 and the electrodeless fluorescent lamp shown in FIG. 2). It has a corner with a radius of curvature of 1 O mm or less instead of the 200) raised portion.

The corners formed by the top of the envelope and the sidewalls of the envelope can have a “mushroom” shape with an angle much less than 90 ° (Figure 5B). The corner having a radius of curvature r of 10 mm or less may not be formed over the entire circumference of the envelope. The envelope may also have an irregular shape without azimuthal symmetry, as shown in FIG. 5C. The corners 42 formed by the top of the envelope and its side walls also have no azimuthal symmetry. The electrodeless fluorescent lamp according to the second embodiment of the present invention operates similarly to the electrodeless fluorescent lamp according to the first embodiment.

The application of the principles of the present invention is not limited to electrodeless fluorescent lamps. For example, in the present invention, the fluorescent film coating 18 is not applied to the inner wall of the envelope 1 (FIGS. 1 and 2), so that light due to discharge is directly emitted to the outside of the envelope 1. The present invention can be applied to the electrode discharge lamp based on the same principle as the above-described operation principle. .

The application of the present invention is not limited to electrodeless discharge lamps that do not use amalgam. Even in the electrodeless discharge lamp using amalgam, when the ratio of mercury in the amalgam is high, the effect of lowering the temperature of the coldest point by the protuberances or corners increases. The principle of the present invention can be applied as long as the discharge gas enclosed in the envelope of the electrodeless discharge lamp contains mercury vapor. Further, any vaporizable metal may be used instead of or in addition to mercury.

While changes and modifications are possible within the spirit and scope of the invention, it is intended that the invention be limited only by the scope of the appended claims. '' Industrial applicability

The electrodeless discharge lamp of the present invention has a raised portion formed on an envelope and protruding toward the outside of the envelope. This lowers the temperature of the ridges, which increases lamp efficiency.

Claims

The scope of the claims

1. an envelope filled with discharge gas,

A coil for generating an electromagnetic field in the envelope,

A ridge formed on the envelope and protruding toward the outside of the envelope;

With

An electrodeless discharge lamp having a tube wall load of 0.05 WZcm ² or more.

2. The electrodeless discharge lamp according to claim 1, wherein the envelope has a concave cavity, and the coil is disposed inside the concave cavity.

3. The electrodeless discharge lamp according to claim 1, further comprising a ferrite core, wherein the coil is wound around the ferrite core.

4. The electrodeless discharge lamp according to claim 1, wherein a maximum thickness and a minimum thickness of the envelope at the raised portion are both 0.1 mm or more and 2 mm or less.

5. The electrodeless discharge lamp according to claim 1, wherein the height of the raised portion is less than 7 mm.

6. An envelope filled with discharge gas,

A coil for generating an electromagnetic field in the envelope;

A ridge formed on the envelope and protruding toward the outside of the envelope; With

An electrodeless discharge lamp, wherein an inductive coupling power frequency of the coil is 50 kHz or more and 1 MHz or less.

7. The electrodeless discharge lamp according to claim 6, wherein a tube wall load is 0.05 WZcm ² or more.

8. The electrodeless discharge lamp according to claim 6, wherein the envelope has a concave cavity, and the coil is completely disposed inside the concave cavity.

9. The electrodeless discharge lamp according to claim 6, further comprising a ferrite core, wherein the coil is wound around the ferrite core.

10. The electrodeless lamp according to claim 6, wherein a maximum thickness and a minimum thickness of the envelope at the ridge are both 0.1 mm or more and 2 mm or less.

1 1. The electrodeless discharge lamp according to claim 6, wherein the height of the raised portion is less than 7 mm.

12. An envelope filled with discharge gas,

A coil for generating an electromagnetic field in the envelope;

With

The electrodeless discharge lamp, wherein the envelope has a side wall and a top, and a radius of curvature of a corner formed by the side wall and the top is 10 mm or less.