TWI546843B - A magnetron powered lamp - Google Patents

Description

Magnetron power supply lamp

The invention relates to a lamp incorporating a magnetron powered source.

A light source is claimed in the European Patent Publication No. EP 1 307 899, which is incorporated herein by reference in its entirety, which is incorporated herein incorporated herein in , which is coupled to the waveguide and contains a gas fill that emits light when receiving electromagnetic energy from the waveguide, the source being characterized by:

(a) the waveguide includes a body consisting essentially of a dielectric material having a dielectric constant greater than 2, a loss tangent of less than 0.01, and a DC collapse threshold greater than 200 kV/inch, one inch吋 is 2.54cm;

(b) the waveguide is sized and shaped to support at least one electric field maximum in the waveguide at at least one operating frequency in the range of 0.5 to 30 GHz;

(c) a cavity that will depend on the first side of the waveguide;

(d) the bulb is positioned in the cavity at a location having an electric field maximum during operation, the gas fill forming a luminescent plasma upon receiving microwave energy from the resonant waveguide body;

(e) A microwave feeder will be positioned within the waveguide body, the microwave feeder being adapted to receive microwave energy from the energy source and to closely contact the waveguide body.

In the international patent application No. PCT/GB2010/000911 filed on May 6, 2010 (the first light source and starter application of the inventor of the present invention), the inventor of the present invention has explained and claimed A light source to be powered by microwave energy, the light source having:

‧ a solid plasma crucible composed of a material that transmits light to allow light to be emitted therefrom, the plasma crucible having a closed gap in the plasma crucible;

‧ a Faraday cage surrounding the plasma crucible, the Faraday cage at least partially transmitting light to allow light to be emitted from the plasma crucible while sealing the microwave;

‧ a filler in the closed space, which is composed of a material that can be excited by microwave energy to form a luminescent plasma therein;

An antenna, which is arranged in the plasma crucible, for transmitting microwave energy induced by the plasma to the filler, the antenna having:

‧ a connecting wire extending to the outside of the plasma crucible for coupling to a microwave energy source;

The light source also contains:

a controllable microwave source that is coupled to the antenna connection line;

a starter for activating the plasma in the filler in the closed space;

‧ a detector for detecting the activation of the plasma;

A control circuit for powering the microwave source at a low power and synchronously with the starter, and switching off the starter and increasing the power of the microwave source after detecting the activation of the plasma.

The following definitions are used in the first light source and starter application of the inventor of the present invention and in the present application:

‧ "Microwave" is not intended to mean a precise frequency range. The inventors of the present invention used "microwave" to represent three size classes ranging from about 300 MHz to about 300 GHz;

‧ "Light transmission" means that the material (used to constitute an article described as light transmissive) is transparent or translucent;

‧ "plasma" refers to a sealed body surrounding a plasma that will be in the gap when the filler of the void is excited by microwave energy from the antenna;

‧ "Faraday cage" refers to a conductive envelope of electromagnetic radiation that at least does not substantially transmit electromagnetic waves (ie, microwaves) at the operating frequency.

EP 1307899 and the inventor's first source of light source and the starter application are as follows:

A microwave plasma source has:

‧ a Faraday cage used to define a waveguide;

‧ a body made of a solid dielectric material that at least substantially masks the waveguide in the Faraday cage;

‧ a sealed void in the waveguide containing material that can be excited by microwaves;

‧ used to introduce plasma excited microwave into the waveguide;

‧ This arrangement will cause a plasma to be created and emit light in the gap when a microwave of a determined frequency is introduced.

Such a source of light will be referred to herein as a "Microwave Plasma Light Source" or MPLS.

The microwave light source of the first light source and starter application of the inventor of the present invention is hereinafter also referred to as a Light Emitting Resonator or LER.

In the international patent application No. PCT/GB2011/000920, filed on June 17, 2011, the inventor of the present invention, the inventor of the present invention has explained and claimed A power supply for a magnetron, comprising:

‧ a DC voltage source;

‧ a converter for boosting the output voltage of the DC voltage source, the converter having:

‧ a capacitive-inductive resonant circuit,

a switching circuit that is adapted to drive the resonant circuit at a varying frequency above the resonant frequency of the resonant circuit, the varying frequency being controlled by a control signal input to provide an alternating voltage,

a transformer that is connected to the resonant circuit to boost the AC voltage,

a rectifier for rectifying the elevated AC voltage into an elevated DC voltage for application to the magnetron;

‧ a measuring member for measuring a current from the DC voltage source through the converter;

a microprocessor that is programmed to generate a control signal indicative of the desired output power of the magnetron;

‧ an integrated circuit that is arranged in a feedback loop and adapted to apply a control signal to the signal based on the signal from the current measuring component and the signal from the microprocessor A converter switching circuit for controlling the power of the magnetron at the desired power.

The power supply (i.e., one of the power supply applications of the inventor's magnetron power supply application) is directed to an early power supply using differently arranged operational amplifiers and microprocessors of different arrangements. Improvement.

Again, the following additional definitions are used in this application: "Magnetron, Switched Converter Power Circuit" or the following components of the power supply referred to by MSCPC. :

a converter that is adapted to be driven by a DC voltage source and produces an AC current output having:

‧ a resonant circuit comprising an inductor and a capacitor ("LC circuit") that exhibits a resonant frequency, and

a switching circuit that is adapted to switch the inductance and the capacitance to generate a switched alternating current having a frequency greater than a resonant frequency of the LC circuit;

‧ an output transformer for increasing the voltage of the output AC current;

‧ Rectifier and smoothing circuit, which is connected to the secondary side circuit of the output transformer for supplying the increased voltage to the magnetron.

It is an object of the present invention to provide an improved lamp that utilizes an MSCPC and an actuator in the first light source and actuator application modified from the inventor of the present invention.

According to the present invention, there is provided a magnetron power supply lamp, the magnetron power supply lamp comprising:

‧ a microwave plasma light source (MPLS);

‧ a magnetron that will be arranged to supply power to the MPLS;

‧ a magnetron, switched converter power circuit (MSCPC) that is arranged to supply power to the magnetron;

a microprocessor that is arranged to control the MSCPC;

‧ an actuator for activating plasma in the filler in the closed gap of the MPLS, the initiator comprising:

a starter electrode that is arranged to apply a starter voltage to the closed gap,

‧ A starter circuit that includes:

‧ a capacitor,

a selective charging member for selectively charging the capacitor from a switching point in the MSCPC,

a discharge member for discharging the capacitor,

‧ a transformer that has:

‧ a primary side coil that is arranged to receive a discharge current from the capacitor, and

a secondary side coil that is arranged to generate the actuator voltage, the secondary side coil being connected to the actuator electrode for applying a starter voltage to the sealed gap;

‧ a detector for detecting the activation of the plasma;

among them:

‧ The microprocessor will be arranged to elect to charge the capacitor before the detector detects that the plasma has started to activate the plasma.

The present invention is designed such that the selective charging member may be an electronic switch that normally isolates the switching point of the discharge member from the power circuit; however, in a preferred embodiment, the selective charging member is a An electronic switch that typically grounds the discharge member. In either case, the state of the switch will be changed for the starter operation.

Further, in a preferred embodiment, the discharge member for discharging the capacitor is a gas discharge unit. Alternatively, a trigger diode can be used.

Further, in a preferred embodiment, the microprocessor controls the MSCPC through an integrated circuit that is arranged in a feedback loop and adapted to be derived from A comparison result of the signal for measuring the component of the MSCPC and the signal from the microprocessor applies a control signal to the converter switching circuit for controlling the power of the magnetron at the desired power.

Referring to Figure 1, the LER lamp shown has a quartz crucible 1 having a centrally sealed void 2 containing a material 3 that can be excited by microwaves as a plasma. The crucible will be enclosed in a Faraday cage 4 defining a waveguide in which the microwave will resonate during operation of the lamp. An antenna 5 enters the raft next to the filler, the antenna having a coaxial connection 6 extending from a matching circuit waveguide 7. At the distal end of the crucible is a magnetron 8 which is arranged to transmit microwaves into the waveguide for forward transfer to the crucible.

A starter electrode 11 extends near the end of the gap, and a photodiode 12 is disposed beside it to detect whether the plasma has been illuminated and is emitting light.

A power supply 21 for the magnetron 8 is connected to a voltage source 22 and a microprocessor 23. As shown in FIG. 2, the power supply includes a quasi-resonant converter 101 having MOSFET field effect switching transistors T1, T2. These transistors are switched by an integrated circuit IC1. An inductor L1 and a primary side coil of the transformer TR1 are connected in series to a common point C of the transistors, and capacitors C3, C4 are connected back to the remote contacts of the transistors outside the primary side coil. . The inductors have a resonant frequency with the capacitors, and the converter operates above the resonant frequency such that it is primarily considered to be an inductive circuit by the downstream magnetron circuit. This includes four half-bridge diodes D3, D4, D5, D6 and smoothing capacitors C5, C6 which are connected to the secondary side coil of the transformer and provide DC current to the magnetron 8. The transformer has a coil ratio of 1:10, so a voltage of 4000 volts is applied to the magnetron and the high mains DC voltage on line 105 will typically be 400 volts (at least in Europe).

A coupling capacitor C11 is connected to the common point of the transistors C, the coupling capacitor C11 provides an input to a starter circuit 24. A transistor switch 25 connects the capacitor C11 and a diode D11 in series. When the switch is off, no current will flow in D11. When the switch is turned on, D11 will turn on during the alternating half cycle that occurs at C. A second diode D12 is also turned on and allows current to pass through the discharge capacitor C12. This will gradually charge until the voltage across it reaches the breakdown voltage of a gas discharge tube GDT. Therefore, the capacitor is discharged via the primary side coil of the transformer TR2. The secondary side coil has more turns and a starter voltage is induced in the starter electrode 11. This will be isolated from the Faraday cage 4 and terminate next to the raft, near the gap 2.

The gap generates a pulse whenever the discharge capacitor is discharged. The magnetron will be driven - the actuator will only operate when the converter is operating. Once the plasma in the gap is established, it is detected by the photodiode 12 located beside the actuator electrode 11. The presence of the plasma will be signaled to the microprocessor which will turn on the transistor switch 25.

For the sake of completeness, a current measuring resistor R1, an operational amplifier EA1, and associated components are shown to operate the converter in accordance with the inventors' magnetron power supply application. Another transistor switcher 26 is also shown. With the transistor switcher, for example, if the magnetron current exceeds a limit (for example, when the quality of its magnet deteriorates), the microprocessor can immediately stop the control in an artificially controlled or automatic manner. Power Supplier.

In actual operation, the lamp is not lit, the voltage source (not shown above) Show) and the microprocessor will be switched on. The microprocessor is instructed to turn on the light in accordance with one or more protocols. The microprocessor controls the power supply to apply a low power to the magnetron and the actuator to apply a starter pulse train having a determined duration to the actuator. If the plasma is not activated, the pulse train is repeatedly applied after a delay. This procedure is repeated until the plasma is illuminated. If this procedure fails, the operator will be notified. Once the plasma illumination has been illuminated, the power delivered to the magnetron will increase to the desired level, commensurate with the desired output of the plasma.

Referring to the variation of Fig. 3, the arrangement of the discharge capacitor C12 and the gas discharge tube GDT is interchanged. They will operate in the same way as the operation in Figure 2. The variation also includes a voltage multiplication stage that includes diodes D14, D15 and capacitors C14, C15. This arrangement contains an appropriate value GDT with which the multiplied primary side voltage is applied to the transformer TR2.

1‧‧‧Quartz

2‧‧‧Closed gap

3‧‧‧Materials

4‧‧‧Faraday cage

5‧‧‧Antenna

6‧‧‧ coaxial cable

7‧‧‧Matching circuit waveguide

8‧‧‧Magnetron

11‧‧‧Starter electrode

12‧‧‧Light diode

21‧‧‧Power supply

22‧‧‧Voltage source

23‧‧‧Microprocessor

24‧‧‧Starter circuit

25‧‧‧Transistor Switcher

26‧‧‧Transistor Switcher

101‧‧ ‧ quasi-resonant converter

105‧‧‧ lines

In order to assist the understanding of the present invention, a specific embodiment of the present invention has been described above by way of example and with reference to the accompanying drawings in which: FIG. 1 is a block diagram of a magnetron power supply lamp of the present invention; Shown is a more detailed circuit diagram of a magnetron, switching converter power circuit of the present invention, which is similar to that described in the inventor's magnetron power supply application and incorporates a starter And a schematic diagram of a variation of the diagram of FIG. 1 shown in FIG.

1. . . Quartz crucible

2. . . Closed gap

4. . . Faraday cage

7. . . Matching circuit waveguide

8. . . Magnetron

11. . . Starter electrode

12. . . Light diode

twenty three. . . microprocessor

twenty four. . . Starter circuit

25. . . Transistor switcher

26. . . Transistor switcher

101. . . Quasi-resonant converter

105. . . line

Claims (6)

A magnetron power supply lamp comprising: a microwave plasma light source (MPLS); a magnetron, which is arranged to supply power to the MPLS; a magnetron, switching Converter power circuit (MSCPC), which is arranged to supply power to the magnetron; a microprocessor that is arranged to control the MSCPC; a starter to activate the MPLS a plasma in the packing in the closed space, the actuator comprising: a starter electrode arranged to apply a starter voltage to the sealed gap, a starter circuit comprising: a capacitor, a selective charging member for selectively charging the capacitor from a switching point in the MSCPC, a discharge member for discharging the capacitor, a transformer having: a primary side coil, Will be arranged to receive a discharge current from the capacitor, and a secondary side coil that is arranged to generate the starter voltage, the secondary side coil being connected to the starter electrode for Applying a starter voltage to the enclosed air ; ‧ and a detector for detecting the start of the plasma; Wherein: ‧ the microprocessor is arranged to elect to charge the capacitor before the detector detects that the plasma has started to activate the plasma. A magnetron power-supply lamp according to claim 1, wherein the selective charging member is an electronic switch that normally isolates the discharge member from a switching point of the power circuit. A magnetron power-supply lamp according to claim 1, wherein the selective charging member is an electronic switch that normally grounds the discharge member. The magnetron power-supply lamp of claim 1, wherein the electronic switch is a transistor and the discharge member is a gas discharge tube. The magnetron power-supply lamp of claim 1, wherein the electronic switch is a transistor and the discharge member is a trigger diode. For example, in the magnetron power-supply lamp of claim 1, item 2, or item 3, wherein the microprocessor controls the MSCPC through an integrated circuit, and the integrated circuit is arranged in a feedback mode. And in the loop, adapted to apply a control signal to the converter switching circuit for comparing the signal from the component for measuring the MSCPC with the signal from the microprocessor for the magnetron The power is controlled at the power.