JP2007234433A - Light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source device capable of resonating microwaves by a simple means and continuing the emission of an emissive substance in a light emitting cell even if thermal deformation is generated following the temperature change in a resonator and the resonance frequency of the resonator is changed. <P>SOLUTION: The light source device has a modulation means (voltage-controlled oscillator 9 and sinusoidal wave transmitter 10 for modulating frequencies) for generating microwaves to be modulated for outputting while having frequency distribution with the frequency of microwaves outputted by a microwave oscillator 7 as a center frequency by periodically changing the phase of microwaves outputted from the microwave oscillator 7 on a time axis, thus supplying the microwaves to be modulated outputted from the voltage-controlled oscillator 9 in the modulation means to a resonator 3. In the resonator 3, the light emitting cell 5 enclosing the emissive substance is accommodated, and the emissive substance is excited by the energy of microwaves resonated by the resonator 3 for emitting light. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light source device that emits light by exciting a luminescent material enclosed in a light emitting cell with microwave energy.

  A light source in which a light emitting material such as sulfur, mercury, Ar gas, Xe gas or the like is enclosed in a light emitting cell (bulb) made of quartz glass or the like and the light emitting cell is accommodated in the internal space (cavity) of the microwave resonator An apparatus is conventionally known (see, for example, Patent Document 1).

  In this type of light source device, a microwave having a predetermined frequency (predetermined wavelength) is supplied to a resonator from a microwave oscillator such as a magnetron to resonate, and the light emitting material in the light emitting cell is excited by the energy of the resonated microwave. To emit light.

In this specification, “light” is not limited to visible light, but also includes electromagnetic waves in regions other than visible light (eg, THz wave region, ultraviolet region). That is, the “light” generated by the light source device in this specification is an electromagnetic wave having a wavelength that can be generated by exciting the luminescent material with microwave energy (this depends on the type of the luminescent material). It means an electromagnetic wave with a sufficiently shorter wavelength than the above.
Japanese Patent No. 2583619

  By the way, in the conventional light source device seen in the said patent document 1, etc., the frequency of the microwave output from a microwave oscillator is a single fixed frequency. And the resonator which supplies this microwave is comprised so that the resonant frequency may become the same as the frequency of this microwave.

  On the other hand, in a resonator that resonates microwaves, thermal deformation of the resonator may occur due to a temperature rise due to heat generated by light emission of a light emitting substance in a light emitting cell. When such a resonator is thermally deformed, the actual resonance frequency of the resonator deviates from the frequency of the microwave output from the microwave oscillator, and as a result, the microwave is caused to resonate within the resonator. There is a disadvantage that the light emission of the light emitting substance in the light emitting cell stops.

  In order to prevent such inconvenience, the temperature of the resonator is monitored via a temperature sensor, and the oscillation frequency (frequency of the output microwave) of the microwave oscillator is corrected in real time according to the detected temperature. Conceivable.

  However, the thermal deformation of the resonator generally varies for each resonator even if the resonator has the same specification. Therefore, when correcting the oscillation frequency of the microwave oscillator according to the detected temperature of the resonator as described above, the oscillation frequency of the microwave oscillator corresponding to the detected temperature is set for each resonator. Correction parameters must be adjusted. As a result, the manufacturing cost of the light source device is increased, and the manufacturing work is troublesome.

  The present invention has been made in view of such a background, and even if thermal deformation caused by temperature change of the resonator occurs and the resonance frequency of the resonator changes, simple means can be used regardless of variations in the thermal deformation. Accordingly, an object of the present invention is to provide a light source device that can resonate a microwave in the resonator and thus can continue light emission of a light emitting substance in a light emitting cell.

  In order to achieve the above object, the light source device of the present invention has a resonator having an internal space for resonating a microwave of a predetermined frequency, a microwave oscillator for outputting a microwave to resonate in the internal space of the resonator, A light emitting cell encapsulated in a luminescent material and housed in an internal space of the resonator, and a microwave is supplied from the microwave oscillator to the resonator and resonated in the internal space of the resonator. In the light source device that emits light by exciting the luminescent substance in the light emitting cell with energy, the microwave oscillator is a microwave that is obtained by periodically changing the phase of the microwave of the predetermined frequency on the time axis. A modulation means for generating and outputting a modulated microwave having a frequency distribution having the predetermined frequency as a center frequency, and a modulated signal output from the modulation means; The black wave is characterized in that so as to supply to the resonator.

  According to the present invention, the microwave generated by periodically changing the phase of the microwave of the predetermined frequency on the time axis is generated and output as the modulated microwave by the modulation means. As such a modulation means, a known phase modulator or frequency modulator (one that can change the phase or frequency of the microwave output by the modulation control signal) may be used. Supplementally, “periodically changing the phase of the microwave on the time axis” means that the phase of the microwave (modulated microwave) at each time (instantaneous instantaneous) is a micro of a predetermined frequency. It means that the phase of the wave is changed, and the amount of change in the phase is periodically changed over time (for example, changed in a sinusoidal shape).

  In this case, the modulated microwave output from the modulation means, that is, the modulated microwave supplied to the resonator has a frequency distribution having the predetermined frequency as a center frequency. For this reason, even if the resonator is thermally deformed due to the temperature change of the resonator and the resonance frequency of the resonator is changed from the predetermined frequency, the modulated microwave has no change after the change of the resonator. A component having the same frequency as the resonance frequency is included. In addition, the amount of change in the resonance frequency accompanying the thermal deformation of the resonator (the amount of change from the predetermined frequency) is generally relatively small, although there are variations among individual resonators. Therefore, among the modulated microwaves, the energy intensity of the component having the same frequency as the resonant frequency after the change of the resonator is set to the total energy of the modulated microwaves supplied to the resonator (the modulated microwaves). A sufficiently high intensity can be obtained with respect to the sum of the energy intensities of all frequency components. Therefore, even if thermal deformation occurs due to the temperature change of the resonator, a microwave having the same frequency as the resonance frequency of the resonator after the thermal deformation and sufficiently high energy intensity is transferred to the internal space of the resonator. (Cavity) can resonate. Then, the light emitting substance in the light emitting cell can be excited without any trouble by the energy of the resonating microwaves to emit light.

  Therefore, according to the present invention, even if the thermal deformation caused by the temperature change of the resonator occurs and the resonance frequency of the resonator changes, a simple means (the modulation means) does not depend on the variation of the thermal deformation. Thus, the microwave can be resonated in the resonator. As a result, light emission of the light emitting substance in the light emitting cell can be continued.

  In the present invention, the frequency band is centered on the predetermined frequency, and the ratio of the energy intensity of the modulated microwave in the band to the total energy intensity of the modulated microwave is a predetermined ratio or more. When the frequency band is a high energy frequency band, the modulation means includes a fluctuation range of a resonance frequency of the resonator according to a temperature change of the resonator in the high energy frequency band in the frequency distribution of the modulated microwave. It is preferable that the modulation microwave is generated.

  According to this, even if the resonance frequency of the resonator changes due to thermal deformation of the resonator, a frequency component having the same frequency as the resonance frequency after the change of the modulated microwave is changed to the high energy frequency. Since it can be accommodated in the band, the energy intensity of the frequency component can be surely made sufficiently high. Therefore, excitation and light emission of the luminescent material can be performed more reliably without depending on the change of the resonance frequency accompanying the temperature change of the resonator.

  When the predetermined ratio is 95%, for example, the high energy frequency band corresponds to a so-called occupied band. In addition, as for the fluctuation range of the resonance frequency of the resonator, for example, for a plurality of light source devices having the same specification, the fluctuation range of the resonance frequency under the temperature environment assumed for the light source device is experimentally measured in advance. In addition, the resonance frequency fluctuation range that should be within the high energy frequency band may be specified based on the measurement result. Further, when the modulation means is constituted by, for example, a frequency modulator, the high energy frequency band corresponds to the change width of the frequency of the modulated microwave and the frequency of the signal wave for modulation. By appropriately setting the frequency change width and the frequency of the modulation signal wave, the high energy frequency band can include the fluctuation range of the resonance frequency of the resonator.

  An embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a diagram showing the overall configuration of the light source device of the present embodiment, and FIG. 2A is a diagram showing a micro-wave when the output of a frequency modulation sine wave oscillator 9 provided in a microwave oscillator 7 described later is a constant DC voltage. 2B is a graph showing the frequency distribution of the microwave output from the wave oscillator 7. FIG. 2B shows the microwave output from the microwave oscillator 7 when the output of the frequency modulation limiting wave oscillator 9 is a sine wave signal. It is a graph which shows the frequency distribution of (modulated microwave).

  Referring to FIG. 1, a light source device 1 of the present embodiment includes a resonator 3 having an internal space (cavity) for resonating microwaves, a light emitting cell 5 accommodated in the internal space of the resonator 3, and a resonance. And a microwave oscillator 7 for outputting a modulated microwave to be supplied to the device 3. The modulated microwave is a microwave having a frequency distribution having a predetermined frequency as a center frequency.

  The resonator 3 is a semi-coaxial resonator in the example of this embodiment. The semi-coaxial resonator 3 includes a cylindrical outer conductor 11 and a central conductor 13 provided coaxially with the outer conductor 11 at the axial center thereof. The outer conductor 11 and the center conductor 13 are made of a conductor material such as metal. Further, the center conductor 13 has a rod shape whose cross section (a section perpendicular to the axis of the center conductor 13) is circular. In addition, you may comprise the outer conductor 11 by the metal mesh formed in the cylindrical shape. In that case, the mesh opening of the metal mesh constituting the outer conductor 11 is set to a dimension that does not transmit the microwave resonated in the inner space of the outer conductor 11 (a dimension that is sufficiently smaller than the wavelength of the microwave). .

  One end of the outer conductor 11 (right end in FIG. 1; hereinafter referred to as first end) is a short-circuit surface 15a on the first end side (a microwave reflecting surface that resonates in the inner space of the outer conductor 11). A metal short-circuit plate 17 is provided. In this embodiment, the short-circuit plate 17 is formed integrally with the outer conductor 11 and is electrically connected to the outer conductor 11, and closes the first end portion of the outer conductor 11. The inner surface of the short-circuit plate 17 (the surface facing the inner space of the outer conductor 11) is a short-circuit surface 15 a on the first end side of the outer conductor 11. The short-circuit plate 17 may be configured separately from the outer conductor 11 and fixed to the outer conductor 11 with a fastening member such as a screw.

  At the other end portion of the outer conductor 11 (left end portion in FIG. 1; hereinafter referred to as second end portion), a metal mesh 19 constituting the short-circuit surface 15b on the second end side is electrically connected to the outer conductor 11. The second end of the outer conductor 11 is closed by the metal mesh 19. The inner surface of the metal mesh 19 (the surface facing the inner space of the outer conductor 11) is a short-circuit surface 15b. In this case, the metal mesh 19 is set to a size that does not transmit the microwave that resonates in the internal space of the outer conductor 11 (a size that is sufficiently smaller than the wavelength of the microwave), and It is set to a dimension that can sufficiently transmit light generated by the light source device 1 of the present embodiment (a dimension that is sufficiently larger than the wavelength of the light). A space surrounded by the short-circuit surface 15 b of the metal mesh 19, the short-circuit surface 15 a of the short-circuit plate 17, and the inner peripheral surface of the outer conductor 11 (inner space of the outer conductor 11) is a cavity that resonates microwaves in the resonator 3. It is.

  A coaxial connector 21 is mounted on the outer surface of the short-circuit plate 17 coaxially with the outer conductor 11. The center conductor 13 is inserted into a through hole 17 a formed in the short-circuit plate 17 at the end on the short-circuit plate 13 side, and is coupled to a center conductor (not shown) of the coaxial connector 21. The center conductor 13 is insulated from the outer conductor 11 via an insulator 23 provided around the center conductor 13 in the through hole 17a. The outer peripheral portion of the coaxial connector 21 is electrically connected to the outer conductor 11.

  The center conductor 13 extends coaxially with the outer conductor 11 from the short-circuit plate 17 side toward the metal mesh 19 in the inner space of the outer conductor 11. In this case, since the resonator 3 is a semi-coaxial resonator, the tip of the center conductor 13 is spaced from the short-circuit surface 15 b of the metal mesh 19.

  The resonator 3 in the present embodiment is a semi-coaxial resonator including the outer conductor 11, the center conductor 13, the short-circuit plate 17, the metal mesh 19, and the coaxial connector 21 as described above. In the resonator 3, microwaves can be supplied to the internal space via the coaxial connector 21 and the center conductor 13. Here, for example, when a microwave having a single frequency equal to the center frequency (predetermined frequency) of the modulated microwave is supplied to the resonator 3, the microwave of the predetermined frequency (the wavelength is referred to as λ below) In order to cause resonance in the internal space of the resonator 3, the length L of the center conductor 13 (specifically, the distance from the short-circuit surface 15a to the tip of the center conductor 13) is an odd multiple of λ / 4. It must be set to length. By setting the length of the center conductor 13 in this way, the resonance frequency of the resonator 3 becomes the same as the predetermined frequency. However, the outer conductor 11 and the center conductor 13 of the resonator 3 undergo thermal deformation (thermal expansion) when the temperature rises due to the temperature rise. In this case, in particular, the actual length L of the center conductor 13 changes due to thermal deformation of the center conductor 13, and therefore the actual resonance frequency of the resonator 3 is deviated from the predetermined frequency. Become. In the present embodiment, even if such a resonance frequency shift of the resonator 3 occurs, the resonator 3 can resonate microwaves as will be described later. In the present embodiment, the length L of the central conductor 13 is a length of λ / 4 (more generally, an odd multiple of λ / 4) under a predetermined temperature environment (for example, a room temperature environment). ) Is set.

  The light emitting cell 5 is accommodated in the internal space of the resonator 13 (internal space of the outer conductor 11) between the tip of the center conductor 13 and the metal mesh 19. In the present embodiment, the light emitting cell 5 is formed in a hollow disk shape, and the inner space of the outer conductor 11 is coaxial with the outer conductor 11 in a state where the outer peripheral surface is in contact with the inner peripheral surface of the outer conductor 11. Is housed in. The light emitting cell 5 is filled with a light emitting substance such as sulfur, mercury, argon gas (Ar), xenon gas (Xe) or the like alone or in a mixed state. The type of the luminescent material is selected according to the wavelength (or frequency) of desired light to be generated by the light source device 1. The light emitting cell 5 is made of a material through which microwaves resonated by the resonator 3 can pass and light generated by excitation of the light emitting substance in the light emitting cell 5 can pass through. In the embodiment, it is quartz glass.

  Supplementally, in the present embodiment, the short-circuit surface 15b on the second end side of the outer conductor 11 is configured by the metal mesh 19, but when the light emitted from the light emitting substance in the light emitting cell 5 is visible light, A transparent conductive film (so-called ITO film) is fixed to the end face on the second end side of the outer conductor 11 among both end faces of the light emitting cell 5 in the axial direction, and the transparent conductor is connected to the outer conductor 11. You may comprise the short circuit surface by the side of the 2nd edge part of the outer conductor 11 with a film | membrane.

  Further, the resonator 3 may not be a semi-coaxial resonator, and may be a coaxial resonator, for example. Furthermore, the resonator 3 may be configured to supply microwaves to the internal space via a waveguide.

  In the present embodiment, the microwave oscillator 7 includes a voltage control oscillator 9 and a frequency modulation sine wave oscillator 10 as modulation means in the present invention. The voltage controlled oscillator 9 oscillates and outputs a microwave having a frequency corresponding to the level (voltage value) of the control voltage signal applied to the control terminal 9 a, and the output side thereof is via the coaxial cable 27. And connected to the coaxial connector 21 of the resonator 13.

  The frequency modulation sine wave oscillator 10 outputs a sine wave signal as a control voltage signal for the voltage controlled oscillator 9, and the output side of the frequency modulation sine wave oscillator 10 is voltage controlled via a connection line 25 constituted by a coaxial cable or the like. The control terminal 9a of the oscillator 9 is connected. In this case, the sine wave signal output from the frequency modulation sine wave oscillator 10 is a signal whose level (voltage value) changes in a sine wave shape with a predetermined DC voltage level as a center voltage. The center voltage of the sine wave signal is the frequency of the microwave output by the voltage controlled oscillator 9 when a voltage signal for control (DC voltage at a certain level) is applied to the control terminal 9a of the voltage controlled oscillator 9. Is a voltage value that becomes the predetermined frequency (= the center frequency of the modulated microwave).

  In the microwave oscillator 7 configured as described above, a sine wave signal is applied as a control voltage signal from the frequency modulation sine wave oscillator 10 to the voltage controlled oscillator 9, whereby a predetermined voltage corresponding to the center voltage of the sine wave signal is obtained. A microwave having a frequency microwave as a carrier (carrier wave) and frequency-modulating the carrier with the sine wave signal is generated and output as a modulated microwave by the voltage controlled oscillator 9. Thereby, the microwave oscillator 7 generates and outputs a modulated microwave whose phase on the time axis changes periodically with respect to the phase of the carrier having the predetermined frequency. In other words, the modulated microwave is a microwave whose phase difference with the carrier changes periodically (in a sine wave form) on the time axis.

  Specifically, the frequency of the carrier (the microwave output from the voltage controlled oscillator 9 corresponding to the center voltage of the sine wave signal) is fc, the frequency of the modulation signal wave (the sine wave signal) is fs, Assuming that the modulation microwave frequency is fm and the maximum deviation amount of the modulated microwave frequency fm with respect to the carrier frequency fc (= maximum value of | fm−fc |; hereinafter referred to as the maximum frequency deviation) is Δf, The frequency fm of the modulated microwave is given by the following equation (1). Note that t is time.

fm = fc + Δf · cos (2 · π · fs · t) (1)

That is, the frequency modulation in the microwave oscillator 7 is a modulation that changes (vibrates) the frequency of the modulated microwave in a sine wave shape with respect to the carrier frequency fc.

  Here, if the phase of the modulated microwave on the time axis (phase angle at an arbitrary time t) is θm, the phase θm is the angular frequency (= 2 · π · fm) of the modulated microwave. Since it is a value obtained by time integration, θm is expressed by the following equation (2). The modulated microwave is expressed by the following equation (3).

θm = 2 · π · fc · t + (Δf / fs) · sin (2 · π · fs · t)
= Θc + (Δf / fs) · sin (2 · π · fs · t) (2)

Vm = Vcm · sinθm (3)

Θc (≡2 · π · fc · t) is the phase (phase angle) of the carrier at time t. Vm is the electromagnetic field intensity of the modulated microwave at time t, and Vcm is the amplitude value of the electromagnetic field intensity. Vcm is the same as the amplitude value of the electromagnetic field strength of the carrier.

  In the present embodiment, a modulated microwave represented by Expression (3) is generated by the voltage controlled oscillator 9 of the microwave oscillator 7, and the modulated microwave is transmitted from the voltage controlled oscillator 9 through the coaxial cable 27 to the resonance. Is supplied to the vessel 13. In this case, as seen in Equation (2), the phase difference (θm−θc) between the phase θm (phase angle) of the modulated microwave and the phase θc (phase angle) of the carrier on the time axis is sinusoidal. It will change periodically. As the voltage-controlled oscillator 9 and the frequency modulation sine wave oscillator 10 that generate the modulated microwave by performing the frequency modulation of the carrier as described above, known ones may be used.

  Here, when a constant DC voltage equal to the center voltage of the sine wave signal is applied to the control terminal 9 a of the voltage controlled oscillator 9, the carrier output from the voltage controlled oscillator 9, that is, the output from the microwave oscillator 7. Since the microwave to be generated has a single frequency (predetermined frequency fc), the frequency distribution of the carrier (distribution of the power (energy intensity) of the microwave on the frequency axis) is basically shown in FIG. ), The power (energy intensity) concentrates only on the component of the frequency fc.

  On the other hand, as shown in FIG. 2B, the frequency distribution of the modulated microwave basically has a spread in the frequency range on both sides of the carrier frequency fc. In other words, the power of the modulated microwave is dispersed on both sides around the frequency fc. In the frequency distribution, the power of the component of the frequency fc of the modulated microwave becomes maximum, and the power of each frequency component decreases as the frequency deviates from fc (with the frequency fc). It is a mountain-shaped distribution in which the power reaches a peak value. In this case, the spread of the frequency distribution of the modulated microwave depends on the maximum frequency deviation Δf and the frequency fs of the modulation signal wave. In this embodiment, the maximum frequency deviation Δf and the frequency fs of the modulation signal wave are set in consideration of the fluctuation range of the resonance frequency value accompanying the thermal deformation of the resonator 3 described above. . This will be described later.

  Next, the operation of the light source device 1 of the present embodiment will be described. When the microwave oscillator 7 (the voltage control oscillator 9 and the frequency modulation sine wave oscillator 10) is activated, the sine as a control voltage signal is transferred from the frequency modulation sine wave oscillator 10 to the control terminal 9a of the voltage control oscillator 9 as described above. By applying a wave signal, the voltage-controlled oscillator 9 generates and outputs the modulated microwave (a microwave obtained by frequency-modulating a carrier with a sine wave signal). The carrier frequency (the center frequency of the modulated microwave) is, for example, 2450 MHz.

  Then, the modulated microwave is supplied to the resonator 13 through the coaxial cable 25. In this case, in a room temperature environment (a state where the temperature of the resonator 13 is about room temperature), a microwave having a component having the same frequency fc as the carrier resonates in the internal space of the resonator 13 among the modulated microwaves. . Then, the light emitting substance in the light emitting cell 5 is excited by the energy of the resonating microwave, and emits light. Further, the light passes through the light emitting cell 5 and the metal mesh 19 and is emitted to the outside. Since the frequency fc of the carrier is the center frequency in the frequency distribution of the modulated microwave, the power (energy intensity) of the frequency component is sufficiently high, and the luminescent substance is excited by the energy without causing any trouble to emit light. Can do.

  On the other hand, with the continuous light emission of the luminescent substance in the light emitting cell 5, the resonator 3 is heated and the temperature of the resonator 3 rises. In this case, as described above, the resonance frequency of the resonator 3 changes from the carrier frequency fc due to thermal deformation (thermal expansion) of the center conductor 13 and the like of the resonator 3. At this time, the component of the modulated microwave supplied to the resonator 3 having the same frequency fc as the carrier cannot be resonated by the resonator 3, but the modulated microwave has no change after the change of the resonator 3. Since the component of the resonance frequency is also included, the microwave of the component can be resonated by the resonator 3. Then, by setting the maximum frequency deviation Δf and the frequency fs of the modulation signal wave as described below, the same as the resonance frequency of the modulated microwave after the change of the resonator 3 The power (energy intensity) of the frequency component can be made high enough to excite the luminescent material. For this reason, even if the resonance frequency of the resonator 3 changes due to thermal deformation of the center conductor 13 or the like, a high-energy microwave having the same frequency as the resonance frequency after the change is resonated by the resonator 3, and the luminescent material Excitation / emission can be continued.

  The maximum frequency deviation Δf and the frequency fs of the modulation signal wave are set as follows. That is, in this embodiment, the fluctuation of the resonance frequency of the resonator 3 due to the thermal deformation of the resonator 3 is experimentally measured. In this case, the measurement is performed by actually measuring the resonance frequency of a plurality of resonators 3 having the same specifications while changing the temperature of each resonator 3. And based on the measured value, the fluctuation range of the resonance frequency accompanying the temperature change of the resonator 3 (the minimum value and the maximum value of the fluctuation range of the resonance frequency) is specified in advance.

  Further, in this embodiment, a so-called occupied band (see FIG. 2B) in the frequency distribution of the modulated microwave is set as a high energy frequency band in the present invention, and is specified as described above in this occupied band. The maximum frequency deviation Δf and the frequency fs of the modulation signal wave are set so that the change range of the resonance frequency is included. Here, the occupied band is centered on the center frequency (= carrier frequency fc) in the frequency distribution of the modulated microwave, and the sum of the power of each frequency component of the modulated microwave included in the band (modulated microwave). The ratio of the power in the frequency distribution of the integrated frequency in the section of the occupied band) to 95% or more of the total power of the modulated microwave (the sum of the power in the entire frequency range, which is approximately equal to the total power of the carrier) It is such a frequency band. In this case, the power of each frequency component in the occupied band of the modulated microwave is sufficiently large.

  Here, the occupied band width BW (difference between the upper limit frequency and the lower limit frequency of the occupied band) is the maximum frequency of the modulation signal wave as fsm (this is a constant value fs in this embodiment). Is approximately expressed by the following equation (4). This equation (4) is an approximation of the so-called Carlson bandwidth.

BW = 2 · (Δf + fsm) (4)

Therefore, the lower limit frequency of the occupied band is fc− (Δf + fsm), and the upper limit frequency is fc + (Δf + fsm).

  In this embodiment, the maximum frequency deviation Δf and the frequency fs (= fsm) of the modulation signal wave are included so that the occupied range includes the fluctuation range of the resonance frequency of the resonator 3 specified in advance as described above. ) Is set. In this case, for example, the absolute value of the difference between the maximum value of the fluctuation range of the resonance frequency and the frequency fc of the carrier, and the absolute value of the difference between the minimum value of the fluctuation range and the frequency fc of the carrier When δf is set as the larger one of them, Δf and fsm (= fs) may be set so that Δf + fsm matches δf or Δf + fsm is slightly larger than δf.

  For example, the carrier frequency fc (= the center frequency of the modulated microwave output from the microwave oscillator 7 = the predetermined frequency) is 2450 MHz, and the fluctuation range of the resonance frequency of the resonator 3 is 2450 MHz-500 kHz to 2450 MHz + 500 kHz. At this time, Δf and fsm may be set to 250 kHz and 250 kHz, respectively.

  As described above, by setting Δf and fsm, even if the resonance frequency of the resonator 3 changes due to thermal deformation of the resonator 3, after the change of the resonator 3 of the modulated microwaves. A high-energy microwave having the same frequency as that of the resonance frequency can be resonated by the resonator 3. As a result, as described above, the light emission of the light emitting material in the light emitting cell 5 can be continued without any trouble.

  In the embodiment described above, as the modulation means for changing the phase of the microwave output from the microwave oscillator 7, the voltage-controlled oscillator 9 and the frequency modulation sine wave oscillator 10 perform frequency modulation. However, instead, a phase modulator may be used to change the phase of the microwave. In that case, a microwave having a single frequency (the frequency of the carrier) is output from the voltage controlled oscillator 9, and a phase modulator is interposed between the voltage controlled oscillator 9 and the resonator 3. Good. As the phase modulator, a known one that changes the wavelength of a microwave (carrier) using a dielectric may be used.

The figure which shows the whole light source device structure of one Embodiment of this invention. FIG. 2A is a graph showing the frequency distribution of the microwave output from the microwave oscillator when the output of the frequency modulation sine wave oscillator of the microwave oscillator provided in the light source device of FIG. 1 is a constant DC voltage. FIG. 2B is a graph showing the frequency distribution of the modulated microwave output from the microwave oscillator when the output of the frequency modulation sine wave oscillator is a sine wave signal.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Light source device, 3 ... Resonator, 5 ... Light emitting cell, 7 ... Microwave oscillator, 9 ... Voltage controlled oscillator (modulation means), 10 ... Sine wave oscillator for frequency modulation (modulation means).

Claims (2)

A resonator having an internal space for resonating a microwave of a predetermined frequency, a microwave oscillator for outputting a microwave to resonate in the internal space of the resonator, and a luminescent material are enclosed and accommodated in the internal space of the resonator. The microwave oscillator supplies the microwave to the resonator and excites the luminescent substance in the light emitting cell by the energy of the microwave resonated in the internal space of the resonator to emit light. In the light source device,
The microwave oscillator generates a modulated microwave having a frequency distribution in which the phase of the microwave having the predetermined frequency is periodically changed on the time axis and having a frequency distribution centered on the predetermined frequency. The light source device is characterized in that it comprises a modulating means for outputting and the modulated microwave output from the modulating means is supplied to the resonator.   A frequency band centered on the predetermined frequency, wherein the frequency band in which the ratio of the energy intensity of the modulated microwave to the total energy intensity of the modulated microwave is equal to or greater than a predetermined ratio is a high energy frequency. When the band is set, the modulation means includes the modulated frequency so that the high energy frequency band in the frequency distribution of the modulated microwave includes a fluctuation range of the resonance frequency of the resonator accompanying a temperature change of the resonator. The light source device according to claim 1, wherein the light source device is a means for generating a microwave.

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