KR800001141B1 - Light generation by an electrodeless fluorescent lamp - Google Patents

Abstract

An electrodeless flurorescent lamp has an ionizable medium comprising a particular gas composition at a particular pressure within a sealed envelope. Radio frequency electrical power is applied to an induction coil, the magnetic induction field of which is coupled to the medium. For a particular radio frequency, the magnitude of the induction field is selected to maximize the light emitted by the discharge per watt of the radio frequency power coupled thereto.

Description

Electrodeless discharge lamp

FIG. 1 is a partial cross-sectional side view of an electrodeless discharge lamp with a cover removed from a base.

FIG. 2 is a side cross-sectional view of the lamp of FIG. 1 with the cover attached to the base. FIG.

3 is a schematic circuit diagram of a radio frequency oscillator mounted in the base of the lamp shown in FIG. 1 and FIG.

4 is a schematic circuit diagram of a radio frequency oscillator of FIG.

5 is a third degree diagram showing the efficiency of the lamps of FIGS. 1 and 2 as a function of the frequency and magnitude of the magnetic induction field.

6 is a three-dimensional diagram of discharge parameter pressure, induced field frequency, and magnitude for a fixed discharge forming gas.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electrodeless (eletrodelss) discharges, and more particularly to the improvement of the efficiency of converting power to light using electrodeless discharges.

Incandescent lamps are an important light source for homes and offices. However, glowing filaments are fragile and weaken as they are used, so they break or fall off the support. Therefore, the life of incandescent lamps is short and unpredictable. Moreover, the efficiency of converting power to light is very low, about 15 lumens per watt.

Fluorescent lamps are generally more efficient and more durable than incandescent lamps. However, the use of a conventional fluorescent lamp requires a ballast and a special facility for mounting it. Moreover, the electrode is likely to decompose over time.

Conventionally, there has been a concept of a light source without an electrode. However, such a device is not commercially possible yet.

Conventionally, an air core high frequency transformer has insufficient coupling of energy to discharge when delivering power to an electrodeless arc discharge, resulting in loss of power due to radiation, which is dangerous. It was thought that a device using a high frequency transformer would not operate successfully for a useful period of time with moderate efficiency. Thus, it was claimed that the ferrite core could be incorporated into the induction coil to enhance the coupling of power to the electrodeless arc discharge. However, using ferrite material, the efficiency is likely to be quite bad.

Firstly, ferrite increases the inductance of the induction coil to the extent that proper high frequency operation is impossible. Thus, the device using the ferrite shim is originally a low frequency device and this operation requires an excessively large induction field.

Secondly, the hysteresis loss of ferrite seams is similar to that in which direct or indirect radiation generated during discharge impinges on ferrite seams or materials therebetween and generates heat, and heat is generated by ferrite seams resistance. ), The ferrite seam is heated, and the ferrite seam is heated by the winding wound around the ferrite seam.

It is well known that the permeability of a typical ferrite around the Curie temperature, usually around 100 ° -150 ° C, decreases to a very low value discontinuously. When the eccentric temperature is reached during the operation of the device, the induction coil is practically no-load due to the drastic decrease of the inductor, and the magnitude of the induction field is actually reduced, so that the discharge stops. Iii) destroyed. The cost of ferrite shims for these devices is also comparable to the cost of an electronic system that provides power for discharge. Thus, ferrite shims make the system inefficient and reduce its operational reliability, but also cost more.

In the prior art, the auxiliary discharge initiation circuit applies an electric field, causing the lamp to undergo initial ionization. Subsequently, energy is converted into discharge energy by the induction magnetic field of the ferrite core. The input voltage and current for the primary winding of the ferrite transformer wound five times are 50 V and 0.6 A, respectively, at a frequency of 50 KHz, and the induced voltage and current are 10 V and 3 A, respectively, with a core loss of about 3 W (watts). Is given by The luminous efficiency claimed in this device is 40 lumen / W, but the actual circuit loss is not included in this value.

Experiments show that when ac is obtained at 110VA, the rectified input to this circuit is 155V. The 50V input to be applied to the ferrite transformer can only be obtained by Class A operation. An input of 60W or more is required to obtain a high frequency output of 30W. Therefore, the luminous efficiency of the entire circuit for this device cannot exceed 20 lumens / W, the value of which is slightly larger than that of the conventional array bulb.

According to the present invention, after an electrodeless discharge is initiated in an ionizable medium, the discharge continues in the medium, which is a specific gaseous composition under a certain pressure, and the radio-frequency induced disturbances are combined with the medium. The frequency and magnitude of the induced magnetic field are determined so that the free electrons in the medium can be accelerated to the ionization rate within a distance equal to the mean free path in approximately one quarter of the period of the induced magnetic field. This optimizes the efficiency of converting radiofrequency power to light by discharging.

In general, the limits of the frequency and magnitude of the radio frequency induction field that can be generated efficiently are determined by the current state of the art of electronic components. Thus, one feature of the present invention is to select the magnitude of the induced disturbance for a given frequency, gas pressure and gas composition to maximize the efficiency of converting radiofrequency power to light. Another feature of the present invention is to select the magnitude of induction field, gas pressure and frequency of induction field for a given gas component to maximize the efficiency of converting radio frequency power to light (generally, It is desirable that the frequency be in the range of 3-300 MHz.) As a result, the efficiency of converting DC power into radio frequency power is limited to the frequency and magnitude of the induction magnetic field due to the performance characteristics at the radio frequency of the electronic component. It can also be optimized by keeping

In summary, since the average free stroke of the electrons depends on the specific gas composition and the specific pressure, the frequency and magnitude of the ionizable medium, the gas composition of the ionizable medium, and the induction field determine the efficiency of converting radio frequency power to light. Four interrelated variables. When the other three are constant, the conversion efficiency as a function of any one of these variables will be optimal at a particular value of that one variable.

In this embodiment of the invention, the sealed cover shaped like a bulb of an incandescent lamp is filled with an inert starting gas such as mercury vapor and argon. Fluorescent phosphors are applied inside the lid, and the induction coil is placed in an open cylindrical cavity extending in the lid so that most of the induction field passes through the medium. A radio frequency oscillator having a tuning circuit including a coil in series with a capacitor is installed in a base that is screwed into a conventional incandescent lamp socket.

The oscillator generates electrical energy at a radio frequency of 4 MHz, which is applied to the coil to generate an induction magnetic field. The electric field trapped in the coil initiates the ionization of mercury vapor in the cover, and the induced magnetic field maintains ionization to emit ultraviolet light to impinge on phosphor, phosphor, to generate white light.

An electrically insulated and ultraviolet reflecting layer is reapplied underneath the phosphorus inside the cover portion forming the cylindrical cavity to prevent the loss of ultraviolet light therethrough. In comparison with the prior art, it can be seen that when the discharge system is designed in the manner described below, the efficient energy coupling to the discharge is not a big problem, and the attitude of the discharge is a loss of the resonant circuit of the electronic system. have. Therefore, within practical limits, the constraints arising from the coupling in this design of the induction system are rare in the production of electrodeless arc discharges, and in particular, electrodeless arc discharges are suitable for fluorescing applications.

Therefore, the electrodeless arc discharge is successful in conventional or other dischargers such as high frequency discharge solenoids having various types of discharge vessels, such as spherical or long cylinders, single loops, or bifilar circuits. Can be used as In addition, the shape of an inductor obtained by conformal transformation of a simple resonant loop can effectively excite an electrodeless lamp. Therefore, a two-circuit circuit through which short-circuit high-frequency current flows can be installed close to the longitudinal direction of the lamp so that the induced current returns from one side of the long cylindrical lamp of the lamp to the other. For example, such a circuit can successfully power a discarded conventional fluorescent lamp whose filaments are already worn out.

The present invention does not use ferrite or any other material as a core for the reasons described above. Once the proper discharge parameters are selected, the coupling of high frequency energy from the air core transformer to the discharge is not much of a problem for a person with ordinary ones. In practice, the maximum efficiency of energy transfer to discharge is achieved when the induction coil and plasma become inductance components of the resonant circuit. At resonance, the inductance formed by the induction coil and the plasma and the impedance to the high frequency power supply by a suitable resonant capacitor are by definition only resistance components.

In the prior art, an auxiliary discharge initiation apparatus is commonly required, and in addition, there is a need for a bulb heating method, a capacitive discharge method, and a transformer for applying a high voltage to a neutral gas.

The above apparatuses are unnecessary if the method described in the present invention is used by selecting an appropriate discharge parameter. Moreover, the auxiliary discharge initiation device increases the cost of the system and reduces the reliability. Therefore, the above auxiliaries should be excluded from the design of the electrodeless arc discharge system. Considering the criteria for determining the commercial validity of electrodeless fluorescent lamps, reliability of operating efficiency and cost of components are major factors. This description shows a method of optimizing a low pressure electrodeless arc discharge that produces efficiency similar to conventional fluorescent lamps when designing an electrodeless fluorescent lamp that can be used with standard household products. Reliability can be increased by design according to the optimization method described in the present invention, and can be further increased by eliminating unnecessary parts by the present invention. Thus, it has been found that ferrite seams, multiple windings, auxiliary start circuits, external reflectors, etc., reduce the reliability of the system and are excluded from the prototype circuit design. Eliminating these can reduce costs as well as increase reliability, and has been found to be essential for mass production and sales-oriented products.

The glass cover 10 through which light is transmitted in FIGS. 1 and 2 is filled with a mixture of inert gas such as mercury vapor and argon. The cover 10 looks like a light bulb of an incandescent lamp, but may be spherical or other shapes. Typically the partial pressure of argon is on the order of 1-5 torr. The purpose of argon is to facilitate mercury discharge inside the cover 10 by a penning effect, as will be described later. The open cylindrical cavity 11 extends to the center of the lid 10. The inner surface portion of the lid 10, which forms the cavity 11, is an electrically insulating material such as magnesium oxide or zirconium and is painted with a material that reflects ultraviolet and white light. Paint it up. A layer 13 of fluorescent material, such as halophosphate or fluorophosphate, is applied over the layer 12 of the lid 10 forming the cavity 11. The inner surface of the remainder of the lid 10 is painted with a layer 14 of phosphorus compound, a non-conductive, mandrel 18 in the form of a hollow cylindrical coil of nonmagnetic material. Is sized to enter cavity 11. One end of the mandrel 18 is attached to a base 19, which spirally enters a conventional incandescent light socket. The base 19 is equipped with a radio frequency oscillator having a tuning circuit including an induction coil 20 wrapped on the surface of the mandrel 18. The purpose of the mandrel 18 is to support the coil 20, which can be made of a suitable material at low cost. The end of the coil 20 away from the base 19 is connected to the radio frequency oscillator by an insulated lead through the hollow center of the mandrel 18. The base 19 has contacts 21 and 22 adapted to supply 120 V, 60 Hz AC power to the radio frequency oscillator. When the cover 10 and the base 19 are coupled as shown in FIG. 2, the induction field generated by the coil 20 allows the radio frequency power from the oscillator to be efficiently coupled with the medium from a physical point of view. It lies very close to the ionizable medium in (10). The part of the cover 10 which is in contact with the base 19 is bonded or mechanically fixed by clamps or screws so that the lamp can be replaced if necessary. In the method described below with respect to FIG. 3, the radiofrequency oscillator is designed such that a sufficiently high voltage is applied to the coil 20 when the lamp is first turned on, so that the electric field ionizes the mercury vapor without a separate starting circuit. After the discharge is made, the radio frequency power from the oscillator is connected to the discharge through the induction magnetic field of the coil 20. Ionized mercury vapor mainly produces ultraviolet light having a wavelength of 253.7 nM (nanometer). Some of the ultraviolet light exits to reach the layer 14, where the ultraviolet light is absorbed to excite the fluorescent material to give white light suitable for illumination. The remainder of the ultraviolet light enters into the cavity 11 and is also reflected by the layer 12 and enters the interior of the lid 10 without being absorbed by the layer 13 or through the glass wall.

The white light generated by the layer 13 is also returned by the layer 12 to the interior of the lid 10. This white light passes through layer 14 and cover 10 to contribute to the overall illumination by the lamp. The presence of the layer 12 prevents the loss of ultraviolet or white light through the cover forming the cavity 11 and through the glass wall of the cover 10 thanks to the layer 12 inside the cover 10. Attenuation of ultraviolet rays due to transmission can be prevented.

The method of selecting the operating frequency and the magnitude of the induced magnetic field is well understood by considering the operational needs of the electrodeless arc. The induced voltage that sustains the discharge is determined by the rate of change of the magnetic flux over the discharge passage. Since the discharge area is usually determined by the geometrical requirements of the lamp, it is possible to adjust the induced voltage to an appropriate level by simply adjusting the product of the induction field B and the radian frequency W.

The frequency of the induced magnetic field in low pressure electrodeless ikes should be selected based on the operating pressure and the optimum breakdown criteria for the discharge gas used. This is because unnecessary and excessive losses are accompanied by repeated ionization of the discharge gas between the periodic peaks of the induced sustained voltage.

의 값을 갖는데, 여기서 L은 코일의 인덕턴스이며,

는 유도코일 전류의 시간에 대한 변화율이며, wi의 크기로 주어진다. 그래서 본 발명에서 개시전개는 주파수와 전류에 정비례한다. 외부의 개시장치는 이 파리미터들에 있어서 적당한 선택을 한다면 본 발명에서는 필요로 하지 않는다. 이것을 근거로, 저전압에서 기체를 발생시키는 대부분의 방전에 있어서, 최적화된 주파수는 방전전자가 그의 평균 자유행정과 같은 거리에서 항복전계의 주기의 1/4에 해당하는 시간동안에 이온화 속도로 가속되어야 한다는 점을 고려함으로써 결정될 수 있다. 위의 것보다 높은 주파수는 최대 이온화율 보다 적은 값을 갖게 한다. 왜냐하면 전형적인 전자는 인가된 전계와 위상이 틀리게 되어 이온화 속도에 도달하기 전에 전개의 방향이 바뀌어 전자를 감속하기 때문에 전자는 이온화 충돌이 아닌 열충돌(thermal Collision)을 하게 된다. 위의 것보다 적은 주파수는 최대 이온화율보다 적은 값을 갖는다. 왜냐하면 평균 자유행정의 끝에서의 전자속도는 이온화에 필요한 속도보다 적기 때문이다. 더구나, 두 경우 모두 방전지속을 위한 적절한 이온화는 최적 이온화율보다 적은 것을 보상하기 위하여 유도자장의 크기를 증가시킴으로써 가능하다. 필요한 방전 전력은 유도자장과 그의 미분치의 크기의 제곱에 비례하기 때문에 심각하며 불필요한 전력 손실은 주파수를 잘못 선택했기 때문에 오는 것이다. 저압 무전극 아아크 방전의 대부분의 경우에서 전술한 기준을 근거로 결정된 유도계 주파수는 수 MHz에서 수백 MHz이며 바람직한 것은 3MH에서 300MHz사이이며, 수십와트 정도의 방전 수준에서 저압기체의 방전을 위해서는 수가우스(gauss)의 유도자장이 필요하다. 방전가스의 혼합물을 무전극 아아크 방전에서의 페닝효과를 이용하도록 사용할 경우 중요한 경우가 생긴다. 페닝 효과를 이용하려면 기체를 생성하는 방전가스의 혼합물이 존재해야하며, 혼합물의 다수를 이루는 기체가 소수를 이루는 기체의 이온화 에너지보다 큰 에너지를 갖는 준안정(metastable)상태를 적어도 하나 이상을 소유해야 한다. 알려진 바와같이 선택법칙의 제한에 의하여 준 안정 상태의 방사성 탈기(脫紀, deexcitation)는 거의 발생할 가능성이 없으며 따라서 그러한 상태는 0.01 내지 01초의 긴 수명을 특징으로 하며, 그러한 상태의 감소는 주로 충돌에 의해서이다. 페닝 혼합물에 있어서, 준 안정하게 여기된 다수 기체의 충돌로 인한 감소는 다수 기체의 준 안정 에너지가 소수기체의 이온화 에너지를 초과하기 때문에 소수기체는 이온화된다. 그러므로, 그 과정은 모든 충돌은 이온화 충돌이기 때문에 이온화를 촉진하는데 유효하다, 형광등 기술에 있어서, 페닝 혼합물을 형성하는 간단한 플라즈마는 아르곤과 소량의 수은증기로 구성된다. 저압에서의 수은방전의 보통 형광물질을 여기하는데 쓰이는 253.7nM(nanometer)의 자외선 방사의 효율적인 원천이 된다. 수은의 전기적 항복(eletreical breadkdown)은 10.4ev/atom을 필요로하며, 아르곤의 존재로 촉진되며 아르곤은 11.49ev와 11.66ev의 준안정 상태를 갖는다. 이 혼합물에서, 준안정 상태로 여기된 아르곤의 비교적 긴 수명때문에 수은에 대한 초기 항복 기준은 상당히 늦춰진다. 그러므로 유도자장의 저주파 작동은 순수한 수은에서의 방전보다 페닝 혼합물에서의 방전이 더 잘 일어난다. 일반적으로 방전가스는 헬륨, 네온 혹은 아르곤과 수은의 페닝 혼합물이고 동작할 때의 전체의 압력은 1내지 수토르(torr)인 형광등에 사용하는 경우 수 MHz의 주파수로 충분히 무전극 형광등을 동작할 수 있다. 위에서 결정된 주파수에서 방전 지속을 위한 유도 자장의 크기는 종종 방전통로의 매인치당 1내지 2볼트인 필요한 지속전압으로부터 직접 얻어진다. 요약하면, 유도자계의 크기 및 주파수 매질의 기체구성물, 그리고 기체 압력은 서로 관련되어서, 평균적으로 매질에서의 자유전자가 그의 평균 자유행정과 같은 거리내에서 주파수의 주기의 약 1/4에 해당하는 시간안에 이온화 속도로 가속된다 이것은 무선주파수를 빛으로 변환하는 효율을 최적화한다. 변환효율은 유도자장의 크기, 주파수, 사용된 기체나 기체혼합물의 구성, 그리고 사용된 기체의 압력 혹은 기체 혼합물의 부분압력에 달린 것이므로, 이러한 방법으로 나머지 3파라미터는 일정하게 할 때 이 파라미터중의 어떤 하나의 함수로서의 변환효율은 상기한 한 파라미터의 주어진 값에 대한 최적치를 갖는다. 그리하여 파라미터들 중의 3가지 보통 기체구성물, 압력 그리고 유도자장의 주파수나 크기가 어떠한 값으로 결정되었을 때 나머지 하나의 파라미터 즉, 유도자장의 크기나 주파수를 최적 변환효율을 갖도록 변화시킨다.Just before the initial yield, the induced magnetic field does not interact with the lamp and its contents. Therefore, the qreakdown field must be electrical and of sufficient size to initiate a discharge. Such development is easily provided by the present invention by the axial electric field of the induction coil,

Where L is the inductance of the coil,

Is the rate of change of the induction coil current over time, given by the magnitude of wi. Thus, in the present invention, the start evolution is directly proportional to the frequency and the current. An external initiator is not needed in the present invention as long as a suitable choice is made for these parameters. Based on this, for most discharges generating gases at low voltages, the optimized frequency should be accelerated to the ionization rate for a time equivalent to one quarter of the period of the breakdown field at a distance equal to its average free stroke. Can be determined by considering. Frequencies higher than the above have less than the maximum ionization rate. Because typical electrons are out of phase with the applied electric field and the direction of development is reversed before reaching the ionization rate, the electrons are decelerated, causing the electrons to undergo thermal collisions rather than ionization collisions. Frequencies less than the above have less than the maximum ionization rate. This is because the electron velocity at the end of the mean free stroke is less than that required for ionization. Moreover, in both cases, proper ionization for sustained discharge is possible by increasing the magnitude of the induced magnetic field to compensate for less than the optimal ionization rate. The required discharge power is severe because it is proportional to the square of the magnitude of the induction field and its derivative, and the unnecessary power loss comes from the wrong choice of frequency. In most cases of low-voltage electrodeless arc discharge, the inductance frequency determined based on the above criteria is between several MHz and several hundred MHz, preferably between 3MH and 300MHz, and for the discharge of low-pressure gas at discharge levels of tens of watts, gauss) is required. An important case occurs when a mixture of discharge gases is used to take advantage of the penning effect in electrodeless arc discharge. To take advantage of the penning effect, there must be a mixture of discharged gases that produce a gas, and the majority of the mixture must have at least one metastable state with a greater energy than the ionizing energy of the minority of gases. do. As is known, due to the limitations of the selection law, semi-steady radioactive deexcitation is unlikely to occur and therefore such conditions are characterized by a long life of 0.01 to 01 seconds, the reduction of which is mainly due to collisions. By In the panning mixture, the decrease due to the collision of the quasi-stable excited multiple gases is ionized because the quasi-stable energy of the multiple gases exceeds the ionization energy of the hydrophobic gas. Therefore, the process is effective for promoting ionization because all collisions are ionization collisions. In fluorescent technology, a simple plasma forming a penning mixture consists of argon and a small amount of mercury vapor. It is an efficient source of ultraviolet radiation of 253.7 nM (nanometer), which is used to excite normal fluorescent materials at low pressures. Mercury's electrical breadkdown requires 10.4 ev / atom and is facilitated by the presence of argon, which has a metastable state of 11.49 ev and 11.66 ev. In this mixture, the initial yield criterion for mercury is significantly slowed down due to the relatively long lifetime of the argon excited in the metastable state. Therefore, low frequency operation of the induction field produces better discharge in the penning mixture than discharge in pure mercury. In general, the discharge gas is helium, neon or a penning mixture of argon and mercury, and when used in a fluorescent lamp having a total pressure of 1 to several torr, it is possible to operate an electrodeless fluorescent lamp sufficiently at a frequency of several MHz. have. The magnitude of the induced magnetic field for sustaining discharge at the frequencies determined above is often obtained directly from the required sustain voltage, which is 1 to 2 volts per inch of discharge passage. In summary, the magnitude of the induction field and the gas composition of the frequency medium, and the gas pressure, are correlated so that, on average, the free electrons in the medium correspond to about one quarter of the period of frequency within the same distance as their average free stroke. It is accelerated at the rate of ionization in. It optimizes the efficiency of converting radio frequencies into light. The conversion efficiency depends on the magnitude, frequency of the induction field, the composition of the gas or gas mixture used, and the pressure of the gas used or the partial pressure of the gas mixture, so that the remaining three parameters in this way are constant when The conversion efficiency as any one function has an optimal value for a given value of one of the parameters described above. Thus, when the frequency or magnitude of three common gaseous components, pressures, and induced magnetic fields are determined to some value, the other parameter, that is, the magnitude or frequency of the induced magnetic field, is changed to have an optimum conversion efficiency.

5 shows the conversion efficiency of the discharge as a function of the frequency f and the magnitude B of the induced magnetic field. As shown in the figure, there is a value of B that maximizes the conversion efficiency for any particular frequency, and there is a value of frequency that maximizes the conversion efficiency for any particular size. The optimum value of conversion efficiency is generally the largest between 3 and 300MHz.

6 shows the magnitude B of the induced magnetic field as a function of the frequency f and the inverse of the gas pressure P for a particular gas. When the direct current power is changed to radio frequency power without a large loss of conversion efficiency, the limit of the frequency at which the lamp of the present invention can be produced at a price competing with an incandescent lamp is determined by the current state of the electronic components. Reference is made to FIG. 3 showing the shape of the radio frequency oscillator mounted in the base 19. It is of special significance that no ferrite seam is required to efficiently convert electrical energy into light. The alternating energy of 120V and 60Hz applied to the contacts 21 and 22 is converted into a direct current of about 170V by the rectifier 26. The smoothing capacitor 27 provided at the output of the rectifier 26 filters a direct current. One terminal of the rectifier 26 is grounded. The remaining terminal of the rectifier 26 is connected to the base of the transistor 29 by a bias resistor 28 and to the transistor 29 by a two-wire frequency choke coil 30. The capacitor 31 and the induction coil 20 are connected in series between the collector and the base of the transistor 29. Capacitor 32 is connected between the collector of transistor 29 and ground and capacitor 33 is connected between the base of transistor 29 and ground. The emitter of transistor 29 is connected to ground via bias resistor 34 and capacitor 35. This circuit is a colpitts oscillator, ie a clapp oscillator, modified with a capacitor 31 in series with the coil 20. The frequency of the oscillator is determined by the electrode-to-electrode capacitance of the transistors 29 of the coil 20 and the capacitors 31, 32, 33 (reactance after discharge breakdown represented by dashed lines) Slightly affects the frequency). Coil 30 prevents radio frequency current from passing through to resistor 28 in tuning, and such current is grounded by capacitor 27. Capacitor 31 is coupled to capacitors 32 and 33; Less in comparison: Thus, the linear resonant circuit composed of the capacitor 31 and the coil 20 is close to the revolution near the oscillation frequency, before the breakdown, due to the effective resistance in the linear resonant circuit composed of the capacitor 31 and the coil 20 before breakdown. There is little power consumption, i.e. loss, so the Q value is large, as a result, the serial connection of the capacitor 31 and the coil 20 results in several times the voltage applied to the coil 20 before the breakdown. The electric field generated by the gas is sufficient to ionize mercury vapor to discharge without the help of an argon gas, eliminating the external start circuit, thereby reducing the cost and simplifying the design. Increases and Q of the tuning circuit decreases: As a result, the increase in the voltage across the coil 20 actually decreases.

The circuit of FIG. 3 consists of the following elements: Transistor 29-Motorola 2N6498: Capacitance between collector and emitter of transistor 29-About 100 PF: Between base and emitter of transistor 29 Capacitance of about 400PF: Capacitor (31) -200PF: Capacitor (32) -360PF: Capacitor (33) -3,900PF: Capacitor (35) -2,000PF: Capacitor (27) -150㎌: Resistance (28) -39KΩ : Resistance (34) -20 kHz: coil (30) -40 μH: induction coil (20) -13.7 μH.

The oscillator resonates at 3.6 MHz just before the no-load condition, that is, before the mercury vapor yields. After the breakdown, the inductance reflected by the discharge passes through the tuning circuit, reducing the overall effective inductance of the tuning circuit. Likewise, the effective capacitance of the induction coil increases near the discharge, and the power absorbed by the discharge seriously increases the effective series resistance of the tuning circuit. As a result, the frequency of the oscillator increases to about 4 MHz under load conditions. Applying an input voltage of 60 Hz and an effective value of 120 V: “When measuring with an AC wattmeter on the wall, the circuit consumes 25W. The DC input power applied to the oscillator is 23.8W and emits 840 lumens of white light. The 2N6498 transistor used has a cutoff frequency of 5MHz and a storage time of 1.4μsec and operates in the circuit described above under Class A operation at 44% measured collector efficiency. Thus, the overall luminous efficiency of the device described above is 840 lumen / 25 W or 33.6 lumen / W: DC luminous efficiency is 840 lumen./23.8 W or 35.3 lumen / W: RF luminous efficiency is 840 lumen / 44 × 23.8 W or 80.2 lumen / W. The use of high-frequency transistors enables Class C operation with a typical collector efficiency of 70%, resulting in an overall system efficiency of 53.5 lumens / W.

A modified oscillator using fewer components than the oscillator of FIG. 3 is shown in FIG. The same components are used for the same numbers in FIGS. 3 and 4. 4 uses a transistor 38 fabricated to have interpolar capacitance providing capacitance to the tuning circuit without the use of an external capacitor. Thus, the capacitance 39 between the collector-emitter of transistor 38 is equal to the capacitance between the capacitor 32 of FIG. 3 and the collector base of transistor 29 and the capacitance 40 between the emitter base of transistor 38. ) Is equal to the capacitance between the capacitor 33 of FIG. 3 and the emitter base of the transistor 29.

Moreover, the component can be reduced by connecting the output of the rectifier 26 to the midpoint of the induction coil 20 with a radio frequency potential of zero. As a result, the coil 30 and the capacitor 27 are unnecessary to block the radio frequency current passing through the resistor 28.

Tens of thousands of generating magnetic fields in combination with ionizable media have been described as induction coils with multiple windings supported on the mandrel, but other methods of generating induction magnetic fields may be used. This fact can be practically applied to operate tubular fluorescent lamps after the filament or electrode is worn out. In such a case, the winding coil is expanded around the entire sheath of the stale fluorescent lamp and excited by the radio frequency oscillator as described above. Such an operation can extend the life of the fluorescent lamp several times.

It will be understood that the foregoing embodiments are selected and illustrate the concept of the invention: the scope of the invention is not limited to the embodiments. Many other different arrangements may be devised by those skilled in the art without departing from the spirit and scope of the invention. For example, radio frequencies higher than 4 MHz will provide higher efficiency, and therefore it is desirable if an electronic circuit element capable of generating such higher radio frequencies efficiently at an affordable price is possible.

Claims (1)

Sealed cover: a medium comprising at least one specific ionizable gas capable of emitting radiant energy when a radio frequency electromagnetic field is applied at a given pressure, and a conversion of radio frequency energy coupled to the medium to emit radiant energy. The intensity and frequency of the induced magnetic field can be selected to optimize efficiency, and a nonmagnetic field placed physically close to the medium in order to couple an electric field of sufficient magnitude to initiate the ionization and a radio frequency induced magnetic field to keep the ionization occurring in the medium within the sheath. An electrodeless discharge lamp consisting of a device including an induction coil wound around a core.

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