UV wave band light source radio frequency source device and working method

Abstract

The invention discloses a UV wave band light source radio frequency source device and a working method. The device comprises an MCU, and a frequency generator, an amplitude and phase modulator, a power amplifier, a forward coupler and a reverse coupler which are sequentially connected in series, the MCU is electrically connected with the frequency generator, the amplitude and phase modulator and the power amplifier, and the MCU is electrically connected with the forward coupler and the reverse coupler through a first detector and a second detector. According to the UV wave band light source radio frequency source device and the working method provided by the invention, the problems of overlarge power consumption, difficulty in maintenance, poor adaptability and the like of a traditional radio frequency source are solved by using a solution of a solid-state amplifier and introducing self-adaptive control and real-time detection of a dynamic frequency synthesizer.

Description

Technical Field

[0001] The invention relates to the technical field of microwave plasma light sources, in particular to a UV band light source radio frequency source device. Background Art

[0002] RF sources are widely used in chemical vapor deposition technology (PACVD), medical, optical and other technical fields; in related application scenarios, there is a demand for high power, and the magnetron architecture is traditionally used. In recent years, with the rapid development of semiconductor technology, the application of solid-state semiconductors is also common. The wavelength of the light source in the UV band is usually between 250nm and 400nm. UV light sources are widely used in industrial fields such as curing, detection, medical treatment, air purification, water treatment, and photolithography.

[0003] Compared with existing light sources, microwave plasma light source (LEP---Light Emitting Plasma) is more environmentally friendly, has high luminous flux density, rich spectral distribution, high luminous efficiency, and is durable. At the same time, changes and optimizations in the formula of lamp beads (lamp tubes) additives can be applied to different scenarios.

[0004] exist Figure 1 In the typical LEP light source structure shown, the microwave RF source is the core and key component of the LEP architecture, which determines the power consumption and service life of the system to a certain extent. The rapid development of solid-state semiconductor technology has made it possible to design and apply RF sources in terms of energy saving, environmental protection, flexibility (adaptability), etc. However, the main disadvantages of the current RF drive source are poor application flexibility, high power consumption, low reliability, and difficult structural heat dissipation design, which leads to a large system weight and volume, and high maintenance costs. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, the present invention provides a UV band light source RF source device, which solves the problems of excessive power consumption, difficult maintenance, and poor adaptability of traditional RF sources by using a solid-state amplifier solution and introducing adaptive control and real-time detection of dynamic frequency synthesizer.

[0006] A UV band light source radio frequency source device comprises: an MCU and a frequency generator, an amplitude modulation phase modulator, a power amplifier, a forward coupler, and a reverse coupler which are connected in series in sequence; the MCU is electrically connected to the frequency generator, the amplitude modulation phase modulator, and the power amplifier respectively, and the MCU is electrically connected to the forward coupler and the reverse coupler respectively through a first detector and a second detector.

[0007] A UV band light source radio frequency source working method, the working method is applied to the UV band light source radio frequency source device as mentioned above, and comprises the steps of:

[0008] S1, the frequency generator generates a radio frequency signal of a certain power at a preset frequency, and the radio frequency signal enters the power amplifier after passing through the amplitude modulation and phase modulation;

[0009] S2, after the radio frequency signal is amplified to the rated power by the power amplifier, it is output to the load detector through the forward coupler and the reverse coupler;

[0010] S3, the forward coupler and the reverse coupler couple the output signal through the forward coupling end as the sampling signal of the output power of the power amplifier and send it to the first detector; the forward coupler and the reverse coupler couple the signal reflected by the load detector through the reverse coupling end as the sampling signal of the reflected power of the power amplifier and send it to the second detector;

[0011] S4, the first detector and the second detector respectively output a DC voltage to the MCU;

[0012] S5, the MCU resets the operating frequencies of the frequency generator and the power amplifier according to the output values ​​of the first detector and the second detector, and adjusts the phase and amplitude of the signal to make the standing wave of the system reach an extreme value.

[0013] The UV-band light source RF source device and working method provided by the present invention can be designed according to the actual application scenario, and can not only work in two states of continuous and pulse signals as needed, but also can adaptively adjust the relevant RF parameters (frequency, phase and amplitude) according to the changes in the actual working scenario (load). The technical solution is simple in design, low in cost, practical and convenient, and solves the problems of high power consumption, low reliability, difficult structural heat dissipation design, and too heavy system weight of the existing RF drive source, and can make the RF source work with the best matching working state; it can provide a high-performance and easy-to-implement intelligent RF drive source for plasma excitation and light source applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram of the existing LEP light source structure;

[0015] Figure 2 This is a hardware schematic diagram of a UV band light source radio frequency source device in an embodiment of the present invention;

[0016] Figure 3 This is a flow chart of a UV band light source radio frequency source working method according to an embodiment of the present invention;

[0017] The symbols in the drawings of the specification are as follows:

[0018] 1. Frequency generator; 2. AM / PM; 3. Power amplifier; 4. Load detector; 5. MCU; 6. PWM unit; 7. Forward coupler; 8. Reverse coupler; 9. First detector and second detector. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] In one embodiment, a UV band light source RF source device is provided, such as Figure 2 As shown, its workflow is as follows Figure 3 shown.

[0021] Specifically, the UV band light source RF source device is mainly composed of a frequency generator, a high-speed operational amplifier, a power amplifier, an AM phase modulator, a power detection circuit and an MCU (main control unit); among them, the frequency generator is mainly used to generate frequency; the high-speed operational amplifier (MOS) is used to amplify pulse signals with different duty cycles; the power amplifier amplifies the RF level of a certain frequency to the rated value; the function of the positive / reverse power detection circuit is to detect the output / reflected power of the power amplifier and send the detection results to the MCU. The MCU mainly controls the frequency generator, power amplifier module, and AM phase modulator to work at the optimal load corresponding frequency.

[0022] The working principle of this UV band light source radio frequency source device is as follows:

[0023] The frequency generator (VCO / PLL) 1 generates a radio frequency signal of a certain power at a certain frequency. The radio frequency signal enters the power amplifier 3 through the amplitude modulation and phase modulation device 2. The radio frequency signal is amplified by the power amplifier to reach the rated power and output to the forward / reverse coupler 7&8, and then output to the load detector 4 through the forward and reverse coupler. The forward and reverse coupler couples the output signal through the forward coupling end as a sampling signal of the output power of the power amplifier and sends it to the first detector; the forward and reverse coupler couples the signal reflected by the load detector through the reverse coupling end as a sampling signal of the reflected power of the power amplifier and sends it to the second detector; the first detector and the second detector 9 output DC voltages V1 and V2 and send them to the MCU. The MCU resets the operating frequency of the frequency generator and the power amplifier according to the values ​​of V1 and V2, and adjusts the phase and amplitude value 2 of the signal to make the system's standing wave reach the extreme value, so as to meet the system working under the optimal load conditions.

[0024] The specific working steps of the microwave plasma power source are as follows:

[0025] 1. The system is powered on and initialized. The MCU assigns initial values ​​to each control variable (VCO / PLL frequency 1, amplitude & phase 2, amplifier gate voltage 3, PWM output value 6). At this time, the detection terminal 9 should be able to detect the expected signal;

[0026] 2. By adjusting the amplitude modulation phase modulator 2, the amplitude of the RF signal is controlled to reach a certain level (such as 30% or 50% of the rated output power), the initial frequency of the frequency generator product is f1 unchanged, the monitoring data is read (corresponding to the first detector and the second detector 9), and the output end standing wave VSWR is calculated; where VSWR refers to the standing wave ratio.

[0027] 3. By controlling the frequency generator (VCO / PLL) 1 to output the signal frequency to f1+△f or f1-△f, reading the monitoring data (corresponding to the first detector and the second detector 9), the output end standing wave VSWR is calculated;

[0028] 4. Set the step length △f1, repeat steps 2 and 3, and search for the optimal VSWR in the frequency range of f1+△f∽f1-△f;

[0029] 5. Adjust the phase of the RF signal through the AM phase modulator 2 to optimize the VSWR;

[0030] 6. According to the search results of steps 2 to 5, the MCU will lock the frequency of the frequency generator at this time;

[0031] 7. The MCU controls the output power of the power amplifier to the rated output and turns on the PWM output connected to the common-phase input terminal of the high-speed operational amplifier.

[0032] The technical solution provided by the present invention solves two main problems. First, the RF source is the source of system energy. Whether the energy can be effectively transmitted is a major issue related to the overall efficiency of the system. The working process of the system is a dynamic process in terms of load performance, and real-time compensation is required to achieve the optimal matching form. Otherwise, poor working efficiency may even damage the RF source. Second, in the stable stage of system operation, trying to make the solid-state amplifier operate under different duty cycle signals can greatly improve the overall operating efficiency of the system, save energy, simplify the design process, and improve the reliability of the long-term operation of the system.

[0033] The above is an explanation of the UV band light source RF source device and working method of the present invention, which is used to help understand the present invention; however, the implementation mode of the present invention is not limited to the above-mentioned embodiments, and any changes, modifications, substitutions, combinations, and simplifications made without departing from the principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A UV band light source radio frequency source device, characterized in that: include: The MCU and the frequency generator, the amplitude modulation phase modulator, the power amplifier, the forward coupler, and the reverse coupler are connected in series in sequence; the MCU is electrically connected to the frequency generator, the amplitude modulation phase modulator, and the power amplifier respectively, and the MCU is electrically connected to the forward coupler and the reverse coupler respectively through the first detector and the second detector.

2. The UV band light source radio frequency source device according to claim 1, characterized in that: A PWM unit is also connected between the power amplifier and the MCU, or the power amplifier is driven by the MCU containing the PWM unit.

3. The UV band light source radio frequency source device according to claim 1 or 2, characterized in that: The output ends of the forward coupler and the reverse coupler are connected to a load detector, and an electrical connection path is provided between the load detector and the MCU.

4. A UV band light source radio frequency source working method, characterized in that: The working method is applied to the UV band light source radio frequency source device according to any one of claims 1 to 3, and comprises the steps of: S1, the frequency generator generates a radio frequency signal of a certain power at a preset frequency, and the radio frequency signal enters the power amplifier after passing through the amplitude modulation and phase modulation; S2, after the radio frequency signal is amplified to the rated power by the power amplifier, it is output to the load detector through the forward coupler and the reverse coupler; S3, the forward coupler and the reverse coupler couple the output signal through the forward coupling end as the sampling signal of the output power of the power amplifier and send it to the first detector; the forward coupler and the reverse coupler couple the signal reflected by the load detector through the reverse coupling end as the sampling signal of the reflected power of the power amplifier and send it to the second detector; S4, the first detector and the second detector respectively output a DC voltage to the MCU; S5, the MCU resets the operating frequencies of the frequency generator and the power amplifier according to the output values ​​of the first detector and the second detector, and adjusts the phase and amplitude of the signal to make the standing wave of the system reach an extreme value.

Images