JPS587232B2 - electrodeless fluorescent lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluorescent lamp adapted to directly replace existing incandescent light bulbs.

More particularly, the present invention relates to fluorescent lamps in which ionization is induced by a transformer contained in part in the glass bulb of the lamp.

Incandescent light bulbs are the primary lighting source for domestic and residential lighting.

The lamp generally contains an incandescent filament in a non-ionizing gas housed in a teardrop-shaped glass bulb mounted on, for example, an Edison-type base screwed into a fixed or movable socket.

Despite their widespread use, incandescent light bulbs are relatively inefficient, producing only 15-17 lumens per watt of input, and have a relatively short and unpredictable lifespan.

High-efficiency fluorescent lamps, such as those producing 80 lumens per watt, are an attractive alternative to incandescent lamps.

However, conventional fluorescent lamps require long tubular glass tubes that require auxiliary stabilizers, somewhat limiting the acceptability of the lamps for domestic lighting applications.

Increasing the residential demand for fluorescent lighting with energy savings has been achieved with the development of fluorescent lamps that fit directly into existing sockets and fixtures for incandescent lamps. Light bulb technology is
We were looking for a discharge device that can emit visible light for general lighting without using electrodes, which is a common problem of arc discharge or arc discharge.

Although the concept of electrodeless discharge lamps is quite old, such lamps already combine electrical energy into a gas-containing glass tube hermetically sealed by a ferromagnetic transformer or an air-core transformer to avoid the use of electrodes. He had this idea in mind.

Such devices have not yet proven practical or commercially viable.

The reason for this is that a reasonable efficiency of light emission could not be achieved by using iron transformers or air core transformers due to core losses, among other things.

It has been proposed in the prior art to excite electrodeless gas discharge lamps using electromagnetic induction to transfer electrical energy to the discharge vessel.

Experience in this area has shown that such methods have heretofore been highly impractical.

When air-core transformers are used, the inefficient coupling methods required to provide a reasonable input to the gas discharge result in power losses due to radiation, which is both prohibited and It's dangerous.

Therefore, such devices have not yet been successfully operated at reasonable efficiency for a useful period of time.

Others proposed in the prior art are to use iron cores or ferromagnetic cores.

However, only extremely low frequencies were used in such cores to prevent heating of the core by the eddy current from causing damage to the core.

Using alternating current, it is extremely difficult to operate iron core transformers to convert this type of energy at frequencies in excess of 5 or 10 kilohertz.

Based on empirical results obtained in the inventor's laboratory and calculation results, it has been determined that in an iron core transformer operating at 50 kilohertz, the power loss in the iron core is in the range of about 80 to 90%.

Therefore, it has been found from the foregoing that air core transformers and iron core transformers cannot be operated in practice at the high frequency levels necessary for efficient operation of gas discharge lamps according to the present invention.

No. 3,500,118 and 3,
No. 521,120 describes a fluorescent lamp that uses a magnetically induced high frequency electric field to ionize a gaseous radioactive medium.

Omitting the discharge electrode in the glass bulb of this light bulb increases the lamp life and allows the lamp shape to be compatible with domestic lighting.

No. 3,500,118, issued March 10, 1970, describes an improved electrodeless fluorescent lamp powered by radio frequency.

Although this structure is useful, it is bulky, with a large tubular discharge ring, several ferrites, an iron core, and a remotely mounted power supply, making it difficult to use in many industrial and residential applications. was made improperly.

An even smaller lamp is described in the aforementioned US Pat. No. 3,521.120, issued July 21, 1970.

However, this lamp maintains a high frequency magnetic field in the air surrounding the glass tube, which often constitutes an undesirable source of electromagnetic radiation and interference.

Briefly, the applicant's patent application filed on the same day (title of invention: Fluorescent lamp) describes a fluorescent lamp constructed to be suitable for residential incandescent lamps within a spherical or teardrop-shaped structure. There is.

An annular ferrite core housed within a glass bulb is excited with a radio frequency magnetic field.

This core induces an electrical discharge in the gas enclosed within the lamp.

Radiation from this ionized gas excites the phosphor of conventional lamps on the inner surface of the glass bulb and the outer surface of the iron core to produce visible light.

The magnetic core of the lamp described in the patent application filed on the same day (title of invention: Fluorescent lamp) is entirely housed in a glass bulb in a vacuum state.

Despite the improved efficiency of this lamp, up to a quarter of the radio frequency input power is dissipated within the core and winding structure.

For efficient operation, the operating temperature of the ferrite core and lamp phosphor is generally limited to a range below 125°C.

Therefore, limiting heat transfer from the transformer core is an important factor in determining the maximum illumination output that can be utilized from such lamps. The structure described has a metal rod for heat conduction through the glass bulb, thus dispersing the heat into the atmosphere.

Fluorescent lamp operation and efficiency will be reduced if materials within the glass bulb contaminate the phosphor or act to alter the gas pressure.

Many ferrite materials are suitable for use in this lamp.
It releases gases at lamp pressure, e.g. oxygen and water vapor, which can cause future damage.

Additionally, such ferrite materials are generally unacceptable for phosphor coatings.

The above-mentioned patent application filed on the same date (Title of the invention: Fluorescent lamp) teaches that in order to improve the adhesion of the phosphor, this is done using conventional heating (railing) methods.

) and apply a thin layer of glaze to the ferrite lamp parts to absorb the gas released from the ferrite.

According to the invention, a portion of the ferrite closed core is mounted outside the vacuum glass bulb of the lamp.

Most of these transformer core surfaces are exposed to the atmosphere to provide improved cooling, heat transfer from the ferrite, and winding structure.

The primary winding of the transformer is wound on the outer core portion, which allows the use of less expensive winding materials than required in other lamp embodiments.

In one embodiment of the invention, the transformer core structure is encased in a metal container having a phosphorable surface.

The glass tube layer applied to the ferrite core structure in other lamps is therefore eliminated.

The transformer core structure is sealed to the lamp base using a single lath seal.

The novel features that are considered characteristic of the invention are set forth in the appended claims.

The invention itself, together with other objects and advantages, may be better understood by reference to the following detailed description taken in conjunction with the accompanying drawings.

The operating principle of an electrodeless fluorescent lamp is described in U.S. Patent No. 3 of the present invention.
, 500,118 and 3,521,120.

These principles are best understood with reference to FIG. 1, which is a cross-sectional view of an electrodeless fluorescent lamp having an induction transformer core contained entirely within an ionizable gas.

Base assembly member 1 supporting the base 13 of the lamp beine
A glass bulb 11 that is transparent and capable of being evacuated is attached to 4.

A radio frequency power supply 16 contained within the base assembly directs current through the metal rod 15 and the primary winding 17.

This primary winding is housed within a transparent glass bulb 11.

A radio frequency magnetic field is excited in the annular ferrite transformer core 12.

Radio frequency power source 16 may be any known type.

For example, my U.S. Pat. No. 3,521,120? The inversion circuit described in is suitable for use with lamp operation within its output range.

The space within the glass bulb contains an ionizable gas 19, which is associated with the transformer core.

The radio frequency magnetic field within the transformer core 12 induces an electric field that ionizes the gas 19.

When transformed into an ionized state, the gas emits radiation in the ultraviolet region.The inner surface of the glass bulb 11 and the outer surface of the transformer core 12 are coated with a suitable lamp phosphor 20 of known techniques.

Phosphors are generally capable of absorbing ultraviolet radiation from a gas that peaks at about 2,537 people.

When stimulated, it emits radiation within the visible spectrum, producing high efficiency and satisfying lighting output.

In embodiments of the invention, the ionized gas is not a force that causes light emission, but rather radiation that causes light to be emitted from the fluorescent phosphor.

This provides a relatively low input to the ionized gas.

The reason for this is that the gas itself takes part only in the radiation to stimulate the phosphor, leaving it alone for the required light emission.

The gaseous ionizing medium 19 in lamps of this type is approximately 0.
It is typically a mixture of a noble gas (eg krypton) and mercury vapor at a pressure of 2 to 20 torr.

These are low thermal conductors, and the transformer core 12 and winding 1
7 is generally insufficient to transfer the heat caused by losses.

According to one embodiment of the invention illustrated in FIG. 2, the transformer core assembly is located partly within the glass bulb of the fluorescent lamp and partly outside the glass bulb. .

Transparent outer tube 11 that can be evacuated like prior art lamps
(e.g. glass) is filled with a gaseous ionizing medium 19.

The glass bulb of the lamp has a flat base area 11a with a rectangular groove 26a in which the transformer core assembly 12 with a central winding space 30 is mounted.

As shown in FIG. 3, the assembled member has an annular ferrite core with a rectangular cross section 18 surrounded by an annular metal container 24.

The core assembly 12 is partially placed inside the glass bulb of the lamp and partially placed outside the glass bulb, and a small portion of the core assembly 12 and a space 30 in which the core is placed are placed inside the glass bulb of the lamp. It extends into the atmosphere through the base 11a of the sphere.

The inside of the lamp glass bulb 11 inside the lamp glass bulb and the outer surface of the metal container 24 are coated with a phosphor 20.

The phosphor may be, for example, any of the phosphors of the fluorescent lamps described above.

That portion of the rectangular groove 26a within the core winding space is covered and sealed with a rectangular glass bridge piece 26.

The primary winding 17 extends over the winding space 30 into the metal container 24.
wrapped around.

Current from radio frequency power supply 16 flows through winding 17 and excites the iron core with a magnetic field that is induced to ionize the gaseous medium as described above, producing a visible output.

A heat sink 28 is joined to the metal container 24 at the outer part of the lamp glass bulb 11.

The heat transferred to the sink 28 is dissipated into the atmosphere or conducted to a suitable radiator in the lamp base (not shown).

Details of the construction of metal container 24 are illustrated in FIG.

The container is made of copper, beryllium, aluminum or any other metal suitable to be at low pressure, compatible with the lamp atmosphere, and to receive the fluorescent lamp phosphor 20.

The container 24 is formed with a smooth, unbroken outer shell around the main circumference of the ferrite core 18, but includes a gap around the main circumference of the interior, which gap can accommodate the induced electric field. prevents short circuits.

Electrical insulation and vacuum preservation between this gap is glass sealed 2
Maintained by 7.

Container 24 includes a vitreous layer 23 that enhances the adhesion of phosphor 20.
covered with.

It is clear that the choice of ferrite core material is a key factor in making this lamp operational.

Although the prior art literature describes lamp geometries with air, iron, or other ferromagnetic cores, the inherent losses in the operation of these prior art cores preclude the actual lamp construction. The inventor has determined that this is the case.

As stated in the cited patent, the ferrite material must be chosen to have high magnetic permeability and low internal heat losses at the operating frequencies.

As is well known, ferrite is a ceramic-like substance characterized by having ferrimagnetic properties, and usually exhibits a spinel structure with a cubic crystal lattice, and has the general formula Me-Fe.
I have 20.

Me in the drum is a metal atom.

According to the invention, the core used to ensure effective coupling of electromagnetic energy to the light source must be of material and shape such that the core loss is less than 50%.

Similarly, low core losses reduce core heating, minimize the possibility of breakage, and maximize energy transfer efficiency.

Core losses are preferably kept below 25% of the total power input.

High permeability iron core materials are also required to properly couple radio frequency energy with the gas with as little electromagnetic radiation as possible.

Typically ferrites having a relative permeability of at least 2000 are preferred.

Suitable ferrites are utilized because they have similar properties over the frequency range of 25 kilohertz to 1 megahertz.

Although high frequency operation is preferred in order to minimize ferrite losses, the cost of semiconductors currently available for use in radio frequency power supplies 16 limits the maximum frequency at which practical lamps are operated to approximately 50 kilohertz. do.

Among other materials, the inventors have found ferrite, Model 8100, manufactured by General Corporation, Indiana, Keasby, NJ, USA.

It is characterized by having losses of less than 30 milliwatts/m3 at a peak flux density of 1000 Gauss for 50 kilohertz operation.

In another embodiment of the invention shown in FIGS. 4, 5 and 6, the transformer core assembly 12 is supported by a recessed cylinder 11b extending from the lamp base 11a.

The core assembly member 12 passes through a pair of rectangular grooves 11c on both sides of the cylindrical body 1lb, and is fixed to the grooves with a glass seal 27a.

An annular cover 29 closes the top of the rectangular groove and is sealed to the inner surface of the cylindrical body 1lb and the transformer core assembly member 12.

The core assembly 12 of this embodiment includes a ferrite core 18 whose outer periphery is surrounded by a metal band 25, which supports the core and assists in removing heat from the core.

Portions such as the metal band 25 and the iron core 18 inside the lamp glass bulb 11 are covered with, for example, a glassy layer 23 to easily receive the phosphor 20 and seal the cover 29 and the vane cylinder 11b. I'm making it easy.

In the embodiment described above, the primary winding 17 of the transformer is wound around a ferrite core and a metal strip and is exposed to the outside atmosphere.

It is surrounded by the winding space 30 of the iron core inside the cylinder 1Ib.

A metal heat sink 28 is bonded to the metal band 25 within the cylindrical body 1Ib and functions to conduct and release heat from the core assembly member 12.

Other details of the lamp structure are shown in FIG. 7 for a lamp base 11a with a concave cylinder 11b and a rectangular groove 11c.

A dish-shaped glass cover 29 is shown before being attached to the cylinder 1lb. As an example, the lamp has a concave cylinder body 11b.
and a glass lamp beine 11a provided with a rectangular groove 11c.
It is made by first forming.

The glass-covered transformer core member 12 to which the winding 17 is attached is inserted into the groove 11C and covered with a glass disk 29.

By heating, the glass cylinder 1lb is melted and vacuum-sealed together with the core coating layer and the glass disk 29 (27a in FIGS. 3 and 4). Next, the upper shell (not shown) of the glass bulb is attached to the base. It is sealed, evacuated and filled with gas in the usual manner.

Furthermore, after the sealing work is completed, the transformer winding 17 is applied to the core assembly member 12.

A sealing structure between glass and ferrite is necessary in practice of the present invention.

It can be seen that, as is known in the art, the above seal can be assembled if the coefficient of thermal expansion of the sealing glass is matched to that of the ferrite.

A suitable ferrite has approximately 11 p p m/m at 400°C.
The inventors have determined that it has a linear expansion coefficient of 'C and linear expansion at temperatures up to 700°C.

Many types of glass have coefficients of expansion in this range and can be used.

For example, Corning glass of type AI 19.0, which is of the potash, soda lead type, has an expansion coefficient of 12.4 ppm/°C and is suitable for ferrite sealing.

A1190 glass is commonly used for sealing with iron,
It is also suitable for sealing with beryllium, which has an expansion coefficient of 11.6 ppm/°C.

FIG. 8 depicts a completed lamp assembly incorporating the principles of the present invention.

A lamp base metal 13, for example an Edison type screw base, is attached to one end of the cylindrical base assembly 14.

The base assembly 14 includes a suitable radio frequency power source and ballast circuit 16.

This circuit is more fully described in the inventor's above-mentioned patent application filed on the same day entitled: Fluorescent Lamp.

The radio frequency power supply receives input power line energy from the vane iron 13 and converts it to radio frequency current which is applied by the primary winding 17 to the ferrite core assembly 12 of the transformer.

A light-transmissive, evacuable glass bulb 11 is coated with a phosphor 20 and is attached to one end of the base assembly 14 opposite the base 13.

The base of the glass tube 11a is wrapped with a base assembly member 14,
Supports a concave cylinder 1lb.

An annular ferrite transformer assembly 12 is attached to this cylinder 1ib.

A disk-shaped glass plate 29 covers the innermost end of the cylinder and is sealed to the transformer core assembly 12 and the cylinder 11b.

A fill gas, for example a mixture of mercury vapor and krypton, fills the glass bulb to connect the transformer core assembly 12.

The primary winding 17 is wound around the transformer core assembly member 12 many times and is located inside the glass bulb cylinder 1Ib.

The heat sink 28 is bonded to the transformer core assembly member 12 within the cylindrical body 1Ib and serves to conduct and release heat.

The space within the cylindrical body 1lb and the base assembly 14 may be filled with a thermally conductive resin material (not shown), if desired, to further enhance heat transfer from the core assembly.

From the description of the above embodiments, it can be seen that a structure is provided which provides improved heat transfer characteristics to the windings and core of an electrodeless fluorescent lamp.

The transformer core of this lamp is partially housed within the glass bulb of the lamp, which provides a highly efficient electrical coupling between the transformer and the gaseous ionizing medium and a shape suitable for residential incandescent lamps and luminaires. This acknowledges the structure of the accompanying lamp.

Furthermore, the transformer core is partially located outside the glass bulb of the lamp.
This, while providing increased heat transfer from the core and winding assembly, does not require the direct electrical and vacuum supply features of other lamps.

The transformer core is easily attached to the lamp bulb base using a simple glass preformed structure.

A specific example of the core structure 12 was described in the above example, but
It will be appreciated that each lamp of the present invention may be made using any of the core structures described above or described in the patent applications referenced above.

The objects set forth above and those clearly provided for from the foregoing description have been effectively achieved and some modifications may be made to the above structure without departing from the spirit and scope of the invention, so that they may not be included in the foregoing description. It is understood that all matter contained herein or shown in the accompanying drawings is to be considered illustrative in nature and not limiting.

Embodiments of the present invention are as follows.

(1) further comprising a gas-impermeable glass material disposed in the core structure and adapted to receive the phosphor so that the gas contained within the core structure is separated from the ionizable medium; Claim 1, characterized in that the phosphor is easily attached to the iron core structure.
Lamps listed in section.

(2) the glass bulb further comprises a flat base defining a substantially rectangular hole through which the core structure sealably penetrates the glass bulb; The lamp according to claim 1, which has a rectangular cross section.

(3) The lamp according to (2) above, comprising the iron core structure and a rectangular bridge element sealed to the glass bulb and covering the rectangular hole in the central space of the iron core structure.

(4) The means for energizing the core structure includes a winding that connects the core structure portion outside the glass bulb with a plurality of turns;
a radio frequency power source connected to said winding and adapted to accept input energy at line voltage and frequency and convert said input energy into a radio frequency current in said winding, said radio frequency magnetic field being connected to said radio frequency magnetic field; The lamp according to (3) above, which is guided by an iron core structure.

(5) a hollow cylindrical base member having a first end attached to the glass bulb and enclosing the portion of the core structure outside the glass bulb and enclosing the radio frequency power supply; The lamp according to (4) above, further comprising means attached to one end of the base member relative to the bulb to receive the input energy.

(6) The lamp according to (5) above, wherein the means for receiving the input energy comprises vaneuro gold of the lamp. (7) The core structure has a low loss energy of about 25 kHz;
an annular ferrite core having a high magnetic permeability at frequencies between 1 MHz; an annular metal container surrounding the ferrite core and defining an aperture extending around the periphery of an internal portion thereof; 2. A lamp as claimed in claim 1, comprising an inductive material filling the apertures so that electrical conduction is prevented even around a slight periphery of the container.

(8) The metal container described above (7) is capable of being evacuated.
).

(9) The rectangular hole is adjacent to the inwardly facing end of the tubular protruding piece, and the inwardly facing end of the cylindrical body and the ferrite core structure are sealed to a flat plate. A lamp according to claim 2.

(10) The means for energizing the core structure connects the core with a plurality of turns, and connects the windings in the cylinder with a radio frequency current having a frequency between about 25 kilohertz and 1 megahertz. The above (9) comprising means for energizing the wire.
).

(11) The means for energizing the winding includes a cylindrical base assembly member having one end attached to the base portion of the glass bulb, and a cylindrical base assembly member housed in the base assembly member and receiving input energy at a line voltage and frequency. , a radio frequency power source adapted to convert the input energy into a radio frequency current in the winding, and a radio frequency power supply adapted to convert the input energy into a radio frequency current in the winding, and a radio frequency power source mounted on the base assembly at an opposite end of the glass bulb and receiving the input energy from an existing lampholder. The lamp according to (10) above, comprising a cap of the lamp base adapted to supply the input energy to the radio frequency power source.

(12) The ferrite core structure includes an annular ferrite core with high magnetic permeability and low loss at a frequency between about 25 kHz and 1 MHz, a flat metal band surrounding the outer main periphery of the ferrite core, and a flat metal band surrounding the outer main periphery of the ferrite core; A lamp according to (11) above, comprising an iron core and a layer of gas-impermeable glassy material arranged on a flat metal strip.

(13) Said flat metal strip is made of a material selected from the group consisting of copper and aluminum (121).
The lamp described in.

(14) The above (12) comprising heat dispersion means adhered to the flat metal strip within the tubular protruding piece of the glass bulb.
The lamp described in.

(15) The lamp according to (14) above, wherein the ionizable medium preferably comprises a mixture of krypton and mercury vapor.

(16) The lamp according to (15) above, wherein the ionizable medium has a pressure of between about 0.2 and 2.0 Torr.

[Brief explanation of the drawing]

1 is a front cross-sectional view of one embodiment of an induced ionization fluorescent lamp, FIG. 2 is a side cross-sectional view of a lamp structure incorporating the present invention, and FIG. 3 is a cross-sectional view of the lamp structure of FIG. Front sectional view of 4th
5 is a front sectional view of the lamp structure of FIG. 4; and FIG. 6 is a partial side view of another embodiment of the lamp structure incorporating the present invention. FIG. The structural drawings, FIG. 7, relate to the method of manufacturing the lamp structures of FIGS. 4, 5, and 6, and FIG. 8 is the completed lamp structure including the power source and screw-in base. 11; Glass bulb, 12; Transformer core, 13; Base, 14
; Baine assembly member, 16; power source, 17; winding, 19; ionizable medium, 20; phosphor, 24; metal container.

Claims (1)

[Scope of Claims] 1. A evacuable, light-transmitting envelope having a substantially spherical shell, and a closed loop having an opening in the center, a portion of which is inside the aforementioned envelope, and a portion of which is outside of the envelope. a ferrite core; a means for energizing the core with a radio frequency magnetic field;
an ionizable medium disposed within the envelope, the medium being adapted to maintain an electrical discharge in an electric field directed therein and to emit radiation at a first wavelength when sustaining the discharge; , a light-emitting phosphor adapted to emit visible light when excited by the radiation at the first wavelength. 2 having a substantially spherical shell and having a flat base and a concave cylindrical protrusion, the protrusion having two opposed rectangular holes and having a flat base; an evacuable light-transmissive envelope extending from the envelope; a closed-loop ferrite core having a central opening and sealably penetrating the envelope through the rectangular hole; means for supplying energy with a radio frequency magnetic field; and maintaining an electrical discharge in an electric field contained within said envelope and linked to said core and directed thereto by said ferrite core; , an ionizable medium adapted to emit radiation at a first wavelength when maintaining the discharge, and an ionizable medium disposed within the envelope and on a surface of the ferrite core within the envelope. arranged,
a light-emitting phosphor adapted to emit visible light when excited by radiation at the first wavelength.