JP2004152668A - Xenon lamp driving device, light source equipment, analyzer, microscope as well as diagnostic device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To modulate intensity of light emitted from a xenon lamp. <P>SOLUTION: A certain current is supplied from a power source 11 to the xenon lamp 13 through a first circuit by turning on a first switch SW1 and turning off a second switch SW2 when starting the lighting of the xenon lamp 13 or lighting with direct current. When modulating intensity of the light emitted from the xenon lamp 13y, a certain bias current modulated by a first MOSFET Q1 and a current modulated in amplitude are supplied from the power source to the xenon lamp 13 through a second circuit by turning off the first switch SW1 and turning on the second switch SW2. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a xenon lamp driving device for driving a xenon lamp, a light source device using a xenon lamp, an analyzer using such a light source device, a microscope, a diagnostic device, and a method.
[0002]
[Prior art]
A xenon lamp (Xe lamp) is widely used as a light source for general-purpose spectroscopic analysis and a light source for measurement that has a continuous wavelength in the ultraviolet to near-infrared wavelength range. In particular, almost all Xe lamps are used as light sources for fluorescence measurement, such as fluorescence spectrophotometers and fluorescence detectors for liquid chromatography. To turn on the Xe lamp, a high voltage pulse of tens of thousands of volts is applied between the anode and cathode electrodes of the lamp at the start of lighting. Then, a spark discharge is generated between the electrodes, the impedance between the electrodes is instantaneously reduced to form a current path, and a constant current of several amperes or more is passed to perform DC lighting. Here, the current value is determined by the rating of the lamp.
[0003]
FIG. 10 is a diagram illustrating a conventional DC lighting circuit.
[0004]
When the Xe lamp 13 is turned on, a high voltage is generated from a high voltage pulse generator (starter) included in the power supply 11 to turn on the Xe lamp 13. Thereafter, a constant current is supplied from the power supply 11 to the Xe lamp 13 to perform DC lighting.
[0005]
As described above, it is common sense to drive the conventional Xe lamp in a DC manner. However, in all measurement fields including fluorescence spectroscopy, there is a very strong demand to modulate the emitted light from the light source. For example, in fluorescence spectrometry, when a modulated light source and a lock-in amplifier are combined to obtain a weak fluorescence signal buried in background light (for example, see Non-Patent Documents 1 and 2), or fluorescence phase modulation This applies to a case where it is desired to determine the fluorescence lifetime of a sample using the method (for example, see Non-Patent Documents 3 and 4). Furthermore, in many cases, not only in fluorescence spectrometry but also in absorption spectrometry, it is often desired to modulate the light source for the purpose of improving the signal-to-noise ratio. The same applies to photoacoustic spectroscopy, photothermal lens / photothermal deflection spectroscopy, and the like.
[0006]
Although the purpose is slightly different from that of the above-mentioned modulated light source, a pulse lighting type Xe lamp is commercially available as a flash xenon lamp as a conventional example. In such a lamp, a Xe lamp having a relatively low wattage is pulse-lit, and a spark discharge is performed in a state where the repetition frequency is about 100 Hz and the duty ratio is very small, on the order of several microseconds. Most of its applications are to excite the sample in a delta function and measure the subsequent transient response. The present inventors have proposed a more appropriate method for spark discharge on the order of a repetition frequency of about KHz and a pulse width of several nanoseconds for a pulse discharge xenon lamp for such a purpose (for example, see Non-Patent Documents). 5, 6, 7, 8). It is applied as a time-resolved fluorescence detector for pulse-excited fluorescence lifetime measurement or liquid chromatography (for example, see Non-Patent Document 9). However, this kind of short pulse discharge type Xe lamp cannot be used for the purpose of the modulated light source.
[0007]
On the other hand, a laser diode (LD) and a light emitting diode (LED) can perform pulse lighting very easily, and can also perform current modulation. The present inventors have reported the nanosecond pulse of the LED for a long time, but also proposed a phase modulation type fluorescence life meter using an ultraviolet LED for current modulation (for example, Non-Patent Documents 3 and 4). reference.). However, there are problems of the emission wavelength range and emission power, respectively. At present, it has not yet become a general-purpose spectrometry light source. For such a reason, development of a method for simply modulating the Xe lamp at an arbitrary frequency has been strongly desired. However, pulse lighting of the Xe lamp is theoretically impossible because of the necessity of applying a high-voltage pulse at the start of lighting. Therefore, it is sufficient if the current can be directly modulated while flowing a bias current through the Xe lamp for DC lighting, but no such attempt has been made so far.
[0008]
Therefore, conventionally, for the purpose of modulating a normal DC lighting type Xe lamp, the lamp radiation light is usually modulated using a mechanical chopper, an acousto-optic device, an electro-optic device using a nonlinear optical crystal, or the like. I was However, a mechanical chopper needs to form an image of a light source on a chopper surface, and further form a light beam after passing through the chopper on a target object such as a sample, which results in an increase in device size (for example, , Non-Patent Document 10.). The chopping frequency is at most about 10 KHz. In addition to the chopper and its driver, an optical system for the ultraviolet wavelength and the like also increase the cost as a whole. The acousto-optic and electro-optic elements can be modulated by an external electric signal, but like the chopper, there are problems such as the need for an imaging optical system and the problem of a decrease in spectral transmittance in the ultraviolet wavelength range. is there. In addition, there is a problem that the price of the electro-optical element, including the peripheral control circuit and the high-voltage power supply, becomes extremely high. In the case of an acousto-optic element, the system becomes expensive and complicated, though not as much as in the case of an electro-optic element. Furthermore, it is quite complicated in terms of the system configuration to use them together with the conventional DC lighting mode or to easily switch and use them.
[0009]
[Non-patent document 1]
Takanori Sato, Hironori Suzaki, Tetsuro Iwata, Kentaro Yamamoto, Tamao Kotake, Takashi Inaga, "Fluorescence Detecting NO2 Monitoring Device Using Microchip", IEEJ, Vol. 121-E, No. 9, pp. 507-512, 2001.
[0010]
[Non-patent document 2]
T. Iwata, T .; Takasu, T .; Miyata, T .; Araki, “Combination of a Gated Photomultiplier Tube and a Phase Sensitive Detector for Use in an Intensive Pulsed Situation.”, Occasionally. Rev .. , Vol. 9, No. 1, pp. 18-24, 2002.
[0011]
[Non-Patent Document 3]
T. Iwata, T .; Kamada, T .; Araki, "Phase-Modulation Fluorometer Using an Ultraviolet Light Light-Emitting Diode," Opt. Rev .. , Vol. 7, No. 6, pp. 495-498, 2000.
[0012]
[Non-patent document 4]
T. Iwata, A .; Hori, T .; Kamada, "Ptoton-Counting Phase-Modulation Fluorometer", Opt. Rev .. , Vol. 8, No. 5, pp. 326-330, 2001.
[0013]
[Non-Patent Document 5]
T. Komatsu, T .; Iwata, T .; Araki, "Reduction in Time Jitter for Free-Running, Nanosecond-Pulsed, Xe Lamp by Supplementary Illumination with Blue Lighting-Emitting. Sci. Instrum. . , Vol. 71, No. 4, pp. 1621-1626, 2000.
[0014]
[Non-Patent Document 6]
Tetsuro Iwata, Tomonori Horidome, Toshiyuki Komatsu, Tsutomu Araki, "Spatial transient emission characteristics of self-propelled discharge nanosecond Xe pulsed white light source", Spectroscopy, Vol. 49, no. 5, pp. 243-248, 2000.
[0015]
[Non-Patent Document 7]
T. Iwata, T .; Tanaka, T .; Komatsu, T .; Araki, "An Externally-Controlled, Nanosecond-Pulsed, Xe Lamp Using a High Voltage Semiconductor Switch," Rev. Sci. Instrum. , Vol. 71, No. 11, pp 4045-4049, 2000.
[0016]
[Non-Patent Document 8]
T. Iwata, T .; Tanaka, T .; Araki, T .; Uchida, "Externally-Controlled Nanosecondd Xe Discharge Lamp Equipped with a Synchronous High-Voltage Power on a Yearly Usage in a Second Life." Sci. Instrum. , Vol. 73, No. 9, pp3165-3169, 2002.
[0017]
[Non-Patent Document 9]
T. Iwata, J .; Koshoubu, Y .; Kurosu, T .; Araki, "Time-Resolved High-Performance Liquid Chromatography Fluorescence Detector Utilizing a Nanosecond Pulsed Lighting Journey for the Departure of Trading for the Departure of the Contracting Led. Chromatogr. A, Vol. 859, p. 13-21, 1999.
[0018]
[Non-Patent Document 10]
T. Iwata, M .; Senda, Y .; Kurosu, T .; Tsuji, M .; Maeda, "Construction of Time-Resolved Fluorescence Detector for Amino Compounds after High Performance Liquid Chromatography, Using Chromaography, U.S.A. Chem. , Vol. 69, no. 10, pp. 1861-1865, 1997.
[0019]
[Problems to be solved by the invention]
The present invention has been proposed in order to solve the above-described problems, and has a xenon lamp driving device that modulates the intensity of light emitted from a xenon lamp, and drives a xenon lamp using such a xenon lamp driving device. It is an object of the present invention to provide a light source device, an analyzer using such a light source device, a microscope, a diagnostic device, and a method.
[0020]
[Means for Solving the Problems]
In order to solve the above-described problems, a xenon lamp driving device according to the present invention drives a xenon lamp, and includes a power supply for supplying a current to the xenon lamp, and a constant current from the power supply to the xenon lamp. A first circuit for supplying a constant bias current and an amplitude-modulated current from the power supply to the xenon lamp; and a switching unit for switching between the first and second circuits. .
[0021]
Preferably, the second circuit has current control means for controlling a current supplied to the xenon lamp.
[0022]
Preferably, the current control means is a semiconductor element, and the semiconductor element includes at least one of a MOSFET, a power transistor, or an IGBT (Insulated Gigabit Transistor).
[0023]
Preferably, the switching means is a mechanical switch, an electromagnetic relay, or a high voltage semiconductor switch.
[0024]
Preferably, the power supply has a function of generating a predetermined voltage at the start of lighting of the xenon lamp, and the switching unit switches to the first circuit at the start of lighting.
[0025]
Preferably, the second circuit has the current control means inserted in series with the first circuit.
[0026]
Preferably, the first circuit has current limiting means for limiting a current supplied from the power supply to the xenon lamp, and the second circuit connects the current control means in parallel with the current limiting means It was done.
[0027]
Preferably, the first circuit has first current control means for controlling a current supplied from the power supply to the xenon lamp, and the second circuit is supplied from the power supply to the xenon lamp. A second current control means for controlling the power supply.
[0028]
Preferably, the first and second current control means are semiconductor switching elements, and the semiconductor switching elements include at least one of a MOSFET, a power transistor, or an IGBT (Insulated Gigabit Transistor).
[0029]
Preferably, the xenon lamp driving device according to the present invention drives the xenon lamp, and includes a power supply for supplying a current to the xenon lamp, and the xenon lamp is supplied from the power supply when the voltage of the power supply exceeds a certain value. A first circuit for supplying a current to the xenon lamp from the power supply, and a second circuit connected in parallel with the first circuit for supplying a constant bias current and a current whose amplitude is modulated. Have.
[0030]
Preferably, the second circuit includes current control means for controlling a current supplied to the xenon lamp.
[0031]
Preferably, the current control means is a semiconductor switching element and includes at least one of a MOSFET, a power transistor, or an IGBT (insulated gigabit transistor).
[0032]
Preferably, the power supply has a function of generating a predetermined voltage at the start of lighting of the xenon lamp.
[0033]
Preferably, the first circuit has voltage sensing means that conducts when a certain voltage is exceeded.
[0034]
Preferably, the voltage sensing means is a surge absorber.
[0035]
A light source device according to the present invention includes a xenon lamp and the xenon lamp driving device of any one of the above-described configurations for driving the xenon lamp.
[0036]
The microscope according to the present invention observes the sample using the light whose intensity has been modulated supplied from the light source device.
[0037]
Preferably, the sample is epi-illuminated with light supplied from the light source device.
[0038]
A diagnostic device according to the present invention is for diagnosing tissue, and includes an excitation unit that excites tissue by irradiating light whose intensity is supplied from the light source device and that has been modulated. It has a measuring means for measuring the lifetime of fluorescence or phosphorescence, and a judging means for judging the state of the tissue based on the measured life.
[0039]
Preferably, the excitation unit excites the tissue with light whose intensity is modulated in a sinusoidal manner, and the measuring unit calculates the life from the phase difference between the light having the sinusoidal intensity and the fluorescence or phosphorescence.
[0040]
Preferably, the determination means determines that the tissue is a tumor when the life span exceeds a threshold.
[0041]
Preferably, using the microscope, the excitation means excites the sample by illuminating the sample with light supplied from the light source device, and the measurement means emits fluorescence or phosphorescence from a specific portion of the sample. The life is calculated for the part from the phase difference of
[0042]
The diagnostic method according to the present invention is for diagnosing a tissue, wherein the step of irradiating the intensity-modulated light supplied from the light source device to excite the tissue, and fluorescence or fluorescence from the excited tissue is provided. Measuring the phosphorescent lifetime; and determining the state of the tissue based on the measured lifetime.
[0043]
Preferably, the light supplied by the light source device is a light whose intensity is modulated in a sine wave shape, and the lifetime is calculated from a phase difference from the fluorescence or the phosphorescence.
[0044]
Preferably, when the lifetime of the fluorescence or phosphorescence exceeds a threshold, the tissue is determined to be a tumor.
[0045]
Preferably, using a microscope, a predetermined portion of the tissue is irradiated with light supplied from the light source device, and the life of fluorescence or phosphorescence is calculated from the phase difference of the portion.
[0046]
The analyzer according to the present invention excites a sample by irradiating light whose intensity has been modulated from the light source device, observes fluorescence or phosphorescence from the excited sample, and obtains a result of the observation. Analyze the sample based on that.
[0047]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a xenon lamp (hereinafter, referred to as Xe lamp) driving device, light source device, analyzer, microscope, diagnostic device, and method according to the present invention will be described in detail with reference to the drawings.
[0048]
In this embodiment, a light source device in which a Xe lamp driving device for driving a Xe lamp is combined with a Xe lamp will be described. However, the present invention can also be realized by a single Xe lamp driving device for driving a Xe lamp.
[0049]
FIG. 1 is a diagram illustrating a configuration of the light source device according to the first embodiment.
[0050]
The light source device according to the first embodiment includes a power supply 11, a Xe lamp 13, and first and second switches (switching means) SW1 and SW2. Among these, the power supply 11, the Xe lamp 13, and the first switch SW1 constitute a first circuit for supplying a current from the power supply 11 to the Xe lamp 13 at the start of lighting of the Xe lamp 13 or at the time of DC lighting. I have.
[0051]
The power supply 11 supplies a current to the Xe lamp 13 and includes a starter that generates a high-voltage pulse when the Xe lamp 13 starts lighting. At the start of lighting of the Xe lamp 13, the first switch SW1 is turned on and the second switch SW2 is turned off, and a high voltage pulse is applied from the starter of the power supply 11 to the Xe lamp 13 via the first circuit.
[0052]
When DC lighting the Xe lamp 13, the first switch SW1 is turned on and the second switch SW2 is turned off, and a constant current is supplied from the power supply 11 to the Xe lamp 13 via the first circuit.
[0053]
The light source device according to the first embodiment includes an N-channel first MOSFET (current control means) Q1, first to third resistors R1, R2, R3, and a coupling capacitor C. . The power supply 11 and the Xe lamp 13, the second switch SW2, the first MOSFET Q1, and the first resistor R1 supply current from the power supply 11 to the xenon lamp 13 when modulating the intensity of light emitted from the Xe lamp 13. This constitutes a second circuit for supplying. This second circuit is obtained by replacing the first switch SW1 of the first circuit with a second switch SW2, a first MOSFET Q1, and a first resistor R1. The first resistor R1 limits the source current of the first MOSFET Q1.
[0054]
The light source device according to the first embodiment includes second and third resistors R2 and R3 for setting a bias voltage of the first MOSFET Q1, and a coupling capacitor C for coupling an input signal to the first MOSFET Q1. Have.
[0055]
The second and third resistors R2 and R3 set the bias voltage to be applied to the gate of the first MOSFET Q1 by dividing the voltage supplied from the bias voltage source Vb. The coupling capacitor C supplies the AC component of the signal input to the input terminal S to the gate of the first MOSFET Q1.
[0056]
The first MOSFET Q1 supplies a bias current according to the bias voltage set by the second and third resistors R2 and R3 and the superposition of the AC component of the input signal to the input terminal S input from the coupling capacitor C. And the modulation current is controlled to flow as a drain current.
[0057]
Here, the bias current is a constant current of, for example, about several A required to maintain the arc in the Xe lamp 13. The bias current is set by the values of the first to third resistors R1, R2, R3.
[0058]
The modulation current is a current that modulates the intensity of light emitted from the Xe lamp 13. This modulation current is controlled by an input signal input to the input terminal S. The input terminal S receives, for example, a sine wave of a desired frequency for modulating the intensity of light.
[0059]
As described above, in the Xe lamp 13, while the arc is maintained by the bias current, the intensity of the emitted light is modulated by the modulation current corresponding to the input signal to the input terminal S.
[0060]
The following procedure is required before the light source device of the first embodiment emits light whose intensity is modulated.
[0061]
First, the first switch SW1 is turned on, the second switch SW2 is turned off, and a high voltage pulse is supplied from the starter of the power supply 11 to the Xe lamp 13 via the first circuit to turn on the Xe lamp 13. After the Xe lamp 13 is turned on by the starter, a constant current is supplied from the power supply 11 to the Xe lamp 13 via the first circuit until the state of the Xe lamp 13 is stabilized, and DC lighting is maintained.
[0062]
When the state of the Xe lamp 13 is stabilized after a predetermined time has elapsed from the lighting of the Xe lamp 13, the second switch SW 2 is turned on, the first switch SW 1 is turned off, and the second power is supplied from the power supply 11 to the Xe lamp 13. The current is supplied through the circuit of FIG. In the second circuit, the current supplied to the Xe lamp 13 is controlled by the first MOSFET Q1. That is, the bias current and the modulation current are supplied to the Xe lamp 13 as the drain current of the first MOSFET Q1. The Xe lamp 13 emits light modulated at an intensity corresponding to the modulation current.
[0063]
In the light source device of the first embodiment, at the start of lighting of the Xe lamp 13, a high voltage pulse is supplied to the Xe lamp 13 by a starter provided in the power supply 11, but at this time, the second switch SW2 is turned off. Have been. Therefore, there is no possibility that the first MOSFET Q1 is broken by the application of the high voltage pulse. As described above, in the light source device according to the present embodiment, lighting activation of the Xe lamp 13, direct-current lighting, and lighting with varying light intensity can be executed safely and reliably.
[0064]
FIG. 2 is a time chart showing the measurement results of the source voltage and the light intensity of the Xe lamp 13.
[0065]
2A shows the light intensity (arbitrary unit, positive / negative reversal) of the Xe lamp 13, and FIG. 2B shows the source voltage (arbitrary unit). The horizontal axis is a unit scale of 5 μs.
[0066]
As the light source device, a 35 W type Xe lamp 13 (L2193, Hamamatsu Photonics) and a first MOSFET Q1 (BUK454-200B, Philips Semiconductors) were used.
[0067]
Here, the waveform of the source voltage of the first MOSFET Q1 in the case where a signal having a frequency of 100 kHz is input to the input terminal S and current-modulated, and the radiated light from the Xe lamp 13 are converted into a photomultiplier tube (U7400 Hamamatsu Photonics, The waveform of the oscilloscope received at 50 Ω load was shown. The degree of modulation at this time was about 25%. The maximum value of the modulation degree is determined by the current value at which the Xe lamp 13 is turned off or the light emission becomes unstable and the maximum current capacity of the power supply 11. If the gate voltage and the average drain current of the first MOSFET Q1 and the peak voltage of the sine wave applied to the input terminal S are optimized, it is considered that the modulation degree can be further improved to about 50% (Nihon Kogaku) Meeting, Optics Japan 2002, Abstracts of lectures).
[0068]
FIG. 3 is a diagram illustrating a configuration of a light source device according to the second embodiment.
[0069]
The light source device according to the second embodiment is obtained by inserting a resistor (current limiting means) between the first switch SW1 and the power supply 11 in the light source device according to the first embodiment shown in FIG.
[0070]
In the second embodiment, the power supply 11, the Xe lamp 13, the first switch SW1, and the resistor R supply the current from the power supply 11 to the Xe lamp 13 when the Xe lamp 13 starts lighting or when the DC lighting is performed. Make up the circuit.
[0071]
In addition, the power source 11 and the Xe lamp 13 and the parallel circuit of the first switch SW1 and the resistor R, the second switch SW2, the first MOSFET Q1 and the first resistor R1 emit light emitted from the Xe lamp 13. A second circuit for supplying a current from the power supply 11 to the Xe lamp 13 when modulating the intensity of the Xe lamp. That is, in the second circuit, the second switch SW2, the first MOSFET Q1, and the first resistor R1 are connected in parallel to the first switch SW1 and the resistor R in the first circuit.
[0072]
In the second embodiment, at the start of lighting of the Xe lamp 13 or at the time of DC lighting, the first switch SW1 is turned on and the second switch SW2 is turned off, and the first switch SW1 is supplied from the power supply 11 to the Xe lamp 13. Supply current through the circuit. When modulating the intensity of light emitted by the Xe lamp 13, the first and second switches SW1 and SW2 are turned on, and a current is supplied from the power supply to the Xe lamp 13 via the second circuit. In the second circuit, the current supplied to the Xe lamp 13 is controlled by the first MOSFET Q1.
[0073]
In the second embodiment, the first switch SW1 is always closed, and a current always flows through the resistor R. Therefore, the light intensity of the Xe lamp 13 is controlled by the current flowing through the resistor R and the current flowing through the first MOSFET Q1 connected in parallel to the resistor R.
[0074]
As described above, the second embodiment is a parallel control method because the current is controlled by the parallel circuit of the resistor R and the first MOSFET Q1. On the other hand, the first embodiment can be said to be a series control method since the current is controlled only by the first MOSFET Q1. Whether to use the parallel control method or the serial control method should be determined in consideration of the current (on-resistance) flowing through the first MOSFET Q1, power consumption, modulation depth, and the like.
[0075]
FIG. 4 is a diagram illustrating a configuration of a light source device according to the third embodiment.
[0076]
The light source device according to the third embodiment is different from the light source device according to the second embodiment shown in FIG. 3 in that the first switch SW1 and the resistor R are replaced by a third switch SW3 and a second MOSFET (second MOSFET). Current control means) Q2 and a fifth resistor R5 are connected in parallel. Further, the light source device of the third embodiment also has sixth and seventh resistors R6 and R7 for setting a bias voltage applied to the second MOSFET Q2.
[0077]
In the third embodiment, the power supply 11, the Xe lamp 13, and the parallel circuit of the first switch SW1 and the resistor R, the third switch SW3, the second MOSFET Q2, and the fifth resistor R5 are connected to the Xe lamp. The first circuit supplies a current from the power supply 11 to the Xe lamp 13 at the start of lighting of the LED 13 or at the time of DC lighting.
[0078]
The power supply 11 and the Xe lamp 13 and a parallel circuit of a first switch SW1 and a resistor R, a second switch SW2, a first MOSFET (first current control means) Q1 and a first resistor R1 are provided. , A second circuit for supplying a current from the power supply 11 to the Xe lamp 13 when modulating the intensity of the light emitted from the Xe lamp 13.
[0079]
In the third embodiment, the first switch SW1 is turned on at the start of lighting of the Xe lamp 13, the second and third switches SW2 and SW3 are turned off, and the first and second switches are turned on at the time of DC lighting of the Xe lamp 13. The third switch SW1 and SW3 are turned on, the second switch SW2 is turned off, and current is supplied from the power supply 11 to the Xe lamp 13 via the first circuit.
[0080]
Here, turning off the second and third switches SW2 and SW3 at the start of lighting of the Xe lamp 13 does not damage the first and second MOSFETs Q1 and Q2 due to the high voltage pulse generated by the starter of the power supply 11. That is to ensure.
[0081]
When modulating the intensity of the light emitted from the Xe lamp 13, the first and second switches SW1 and SW2 are turned on, the third switch SW3 is turned off, and the second circuit is supplied from the power supply to the Xe lamp 13. Supply current through.
[0082]
In the third embodiment, the current supplied to the Xe lamp 13 via the first circuit during the DC lighting of the Xe lamp 13 can be controlled by the second MOSFET Q2. That is, at the time of DC lighting, the first and third switches SW1 and SW3 are turned on, and the bias voltage of the second MOSFET Q2 is set by the sixth and seventh resistors R6 and R7. The drain current of the MOSFET Q2 can be controlled. Therefore, the current is controlled by a parallel circuit of the first switch SW1 and the first resistor R1, the third switch SW3, the second MOSFET Q2, and the fifth resistor R5.
[0083]
The control for modulating the intensity of the light emitted from the Xe lamp 13 is the same as in the second embodiment.
[0084]
FIG. 5 is a diagram illustrating a configuration of a light source device according to the fourth embodiment.
[0085]
The light source device according to the fourth embodiment is different from the light source device according to the third embodiment shown in FIG. 4 in that a photodiode 15 for detecting light emitted by the Xe lamp 13 and a signal input from the photodiode 15 And a control unit 19 for performing control based on a signal input from the amplifier 17.
[0086]
Except for these additional elements, the light source device according to the fourth embodiment is the same as the above-described third embodiment. However, in the fourth embodiment, when modulating the intensity of the light emitted from the Xe lamp 13, the second circuit for supplying current from the power supply 11 to the Xe lamp 13 includes the power supply 11 and the Xe lamp 13, A first switch SW1 and a resistor R, a second switch SW2, a first MOSFET Q1 and a first resistor R1, a third switch SW3, a parallel circuit of a second MOSFET Q2 and a fifth resistor R5. It is.
[0087]
In the fourth embodiment, the gate voltage of the second MOSFET Q2 is feedback-controlled by the control unit 19 based on the light intensity of the Xe lamp 13 detected by the photodiode 15.
[0088]
When the intensity of light emitted from the Xe lamp 13 is high, the control unit 19 lowers the gate voltage of the second MOSFET Q2 to reduce the drain current, and when the light intensity is low, increases the gate voltage of the second MOSFET Q2. Increase drain current. The feedback control of the intensity of the light emitted from the Xe lamp 13 is suitable for the measurement of the excitation spectrum in a fluorescence spectrophotometer.
[0089]
FIG. 6 is a diagram illustrating a configuration of a light source device according to the fifth embodiment.
[0090]
The light source device according to the fifth embodiment differs from the light source device according to the first embodiment in that an LC circuit 21 including a coil L and a capacitor C is provided in a path from the power supply 11 to the Xe lamp 13 so as to be switchably inserted. It is a thing.
[0091]
In the fifth embodiment, the third switch SW3 is connected to the contact a and the fourth switch SW4 is connected to the contact c when the Xe lamp 13 starts to be lit or when the DC lamp is lit. Thus, a high voltage pulse can be supplied from the starter included in the power supply 11 to the Xe lamp 13 without being hindered by the inductance of the coil L.
[0092]
On the other hand, when modulating the intensity of the light emitted from the Xe lamp 13, the third switch SW3 is connected to the contact b and the fourth switch SW4 is connected to the contact d. In this case, the bias component, which is a DC component, is supplied from the power supply 11 to the Xe lamp 13 via the coil L, and the modulation current of the AC component is bypassed by the capacitor C.
[0093]
In the fifth embodiment, since the modulation current for modulating the intensity of the light emitted from the Xe lamp 13 is bypassed to the power supply 11, the loss of the AC component is small. Since the loss of the AC component increases as the frequency increases, the fifth embodiment is suitable for modulating the intensity of light emitted from the Xe lamp 13 at a high frequency.
[0094]
FIG. 7 is a diagram illustrating a configuration of a light source device according to the sixth embodiment.
[0095]
The light source device according to the sixth embodiment differs from the light source device according to the second embodiment in that the first and second switches SW1 and SW2 are removed and the resistor R is replaced with a surge absorber (voltage sensing means) SA. is there. The surge absorber SA has a property of conducting when a voltage equal to or higher than a predetermined value is applied. For example, a zener diode having a large current capacity can be used instead.
[0096]
In the sixth embodiment, when a high-voltage pulse is applied to the Xe lamp 13 at the start of lighting of the Xe lamp 13, the surge absorber SA conducts, and the current flows through the surge absorber SA. Therefore, there is no possibility that the high voltage pulse is applied to the first MOSFET Q1 and the first MOSFET Q1 is damaged.
[0097]
When the DC lighting of the Xe lamp 13 or the intensity of the light emitted from the Xe lamp 13 is modulated, the voltage applied to the surge absorber 13 is equal to or lower than a predetermined voltage, the surge absorber 13 does not conduct, and the current flows through the first MOSFET Q1. And flows through the first resistor R1.
[0098]
Thus, in the seventh embodiment, an operation equivalent to that of the light source device of the first embodiment is performed without switching between the first and second switches SW1 and SW2 in the first embodiment. The operation is easy and the operation is reliable.
[0099]
FIG. 8 is a diagram showing a configuration of an epi-illumination type fluorescence microscope constituting the living tissue diagnosis apparatus.
[0100]
The epi-illumination type fluorescence microscope 50 includes a light source 52, a collimator lens 53, a reflecting mirror 54, a sample stage 55, an objective lens 56, a dichroic beam splitter 57, a prism 58, and an eyepiece inside a housing 51. 59 and a photomultiplier tube (PMT) 60.
[0101]
The epi-illumination type fluorescence microscope 50 is supplied with light whose intensity is modulated from the light source device 40, epi-illuminates the sample, and observes the excited fluorescence. The light incident on the epi-illumination fluorescence microscope 50 from the side of the housing 50 from the light source device 40 is turned by the dichroic beam splitter 57 in the housing 50, and the sample on the sample stage 55 is passed through the objective lens 56. Epi-illumination. The sample is excited by this illumination and emits fluorescence.
[0102]
The fluorescence emitted from the sample is observed as an image via the objective lens 56, the beam splitter 57, the prism 58, and the eyepiece 59. A part of the fluorescence transmitted through the beam splitter 57 is detected by the photomultiplier tube 60 as an electric signal.
[0103]
Illumination from the light source 52 incident on the sample stage 55 via the collimator lens 53 and the reflecting mirror 54 is used for positioning the sample on the sample stage 55 and the like.
[0104]
A specific portion of the sample such as the clinical sample positioned as described above is irradiated with light whose intensity is supplied from the light source device 40 and whose intensity is modulated. Then, the lifetime of the fluorescence excited by the light irradiation is measured. Light whose intensity is modulated in a sinusoidal manner is supplied from the light source device 40, and in response to this, fluorescence having a sinusoidal intensity is emitted from the sample. The phase difference between these sine waves is measured, and the lifetime of the fluorescence is calculated from the phase difference.
[0105]
The epi-illumination fluorescence microscope 50 of the present embodiment has a simple structure, is small, and is easy to handle. According to the epi-illumination type fluorescence microscope 50, the fluorescence lifetime of the sample can be measured quickly and easily without damaging the sample such as a clinical sample.
[0106]
The biological tissue diagnostic apparatus includes, in addition to the epi-illumination type fluorescence microscope 50, the above-described light source device that supplies the intensity-modulated light to the epi-illumination type fluorescence microscope 50, the intensity-modulated light, and the light. It has a computer that receives signals obtained by observing fluorescence and determines the state of the tissue based on a predetermined algorithm based on the phase difference between these signals. This computer determines a tissue according to the following method as a method for diagnosing a living tissue.
[0107]
FIG. 9 is a diagram illustrating a diagnosis method for diagnosing living tissue using the living tissue diagnosis apparatus.
[0108]
In this diagnostic method, light such as a sinusoidally modulated light s1 is emitted from a light source device described above to a tissue such as a clinical sample. Then, the phase difference between the fluorescence s2 and s3 having a sinusoidal intensity emitted from the tissue excited by the light irradiation and the irradiated light s1 is measured. Then, the lifetime of the fluorescence is calculated from the phase difference. If the lifetime exceeds the threshold, the tissue is determined to be a tumor, and if not, the tissue is determined to be normal.
[0109]
More specifically, it is as follows. A curve s1 in the drawing indicates a temporal change in the intensity of the excitation light having a sinusoidal waveform supplied from the light source device. Curves s2 and s3 in the figure show a time change of the intensity of the fluorescence excited by the excitation light having the intensity change of the curve s1.
[0110]
Tumor identification is performed as follows. For example, the fluorescence emitted from the normal tissue has a relatively small delay with respect to the excitation light s1 as shown by a curve s2, whereas the fluorescence emitted from the tumor tissue has a relatively large delay with respect to the excitation light s1 as shown by a curve s3. . The curve s3 lags behind the curve s2 by the phase difference θ.
[0111]
Here, assuming that the angular frequency of the excitation light is ω, there is a relationship of tan θ = ωτ between the phase difference θ and the delay time τ, assuming that the fluorescence decay waveform is expressed by a single exponential function. Therefore, the delay time determined by the phase difference is determined, and the life is obtained based on the delay time. Then, if the lifespan of the fluorescence exceeds a predetermined threshold, it is identified as a tumor, and if not, it is determined as normal.
[0112]
As described above, by using the light having the modulated intensity emitted from the light source, it is possible to easily diagnose whether the tissue is a tumor or a normal tissue. In addition, by using the above-mentioned epi-illumination type fluorescence microscope for this diagnosis, the diagnosis of the sample can be easily performed.
[0113]
Note that, in the above-described embodiment, fluorescence has been described, but the present invention can be applied to phosphorescence in the same manner as fluorescence.
[0114]
As described above, according to the present embodiment, an inexpensive and simple modulated Xe light source in the ultraviolet to near-infrared wavelength range can be realized. The present inventor has realized direct current modulation of a Xe lamp for direct current lighting, which was conventionally considered impossible or completely ignored. The modulation circuit is extremely simple, inexpensive, and small, and has an excellent feature that it can be easily switched or used together with the conventional DC lighting Xe lamp without any change in the optical system.
[0115]
The proposed current modulation Xe lamp can be used for the following equipment. Light source for microspectroscopy, fluorescence detector for liquid chromatography, general-purpose fluorescence spectrophotometer, visible / ultraviolet absorption spectrophotometer, light source for photoacoustic, continuous light source for flash photolysis, etc. Also, if the modulation frequency can be increased, there is great utility as a light source for a phase modulation type fluorescence life meter.
[0116]
The present embodiment shows a specific example of the present invention, and the present invention is not limited to this. It will be apparent to one skilled in the art that changes in design and the like are possible without departing from the scope of the invention.
[0117]
【The invention's effect】
As described above, according to the present invention, the intensity of light emitted from a xenon lamp can be modulated.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a light source device according to a first embodiment.
FIG. 2 is a time chart showing measurement results of source voltage and light intensity of a xenon lamp.
FIG. 3 is a diagram illustrating a configuration of a light source device according to a second embodiment.
FIG. 4 is a diagram illustrating a configuration of a light source device according to a third embodiment.
FIG. 5 is a diagram illustrating a configuration of a light source device according to a fourth embodiment.
FIG. 6 is a diagram illustrating a configuration of a light source device according to a fifth embodiment.
FIG. 7 is a diagram illustrating a configuration of a light source device according to a sixth embodiment.
FIG. 8 is a diagram showing a configuration of an epi-illumination type fluorescence microscope.
FIG. 9 is a diagram illustrating a diagnosis method.
FIG. 10 is a diagram showing a conventional DC lighting circuit.
[Explanation of symbols]
11 Power supply
13 Xenon lamp
C coupling capacitor
Q1 First MOSFET
Q2 The second MOSFET
R resistance
R1 First resistance
R2 Second resistance
R3 Third resistance
S input terminal
SW1 First switch
SW2 Second switch

Claims (12)

In a xenon lamp driving device for driving a xenon lamp,
A power supply for supplying current to the xenon lamp,
A first circuit for supplying a constant current from the power supply to the xenon lamp;
A second circuit for supplying a constant bias current and an amplitude-modulated current from the power supply to the xenon lamp;
Switching means for switching between the first and second circuits;
A xenon lamp driving device comprising: 2. The xenon lamp driving device according to claim 1, wherein said second circuit has a current control means for controlling a current supplied to said xenon lamp. 2. The xenon lamp drive according to claim 1, wherein the power supply has a function of generating a predetermined voltage at the start of lighting of the xenon lamp, and the switching unit switches to the first circuit at the start of lighting. apparatus. 2. The xenon lamp driving device according to claim 1, wherein the second circuit has the current control means inserted in series with the first circuit. The first circuit has current limiting means for limiting a current supplied from the power supply to the xenon lamp, and the second circuit has the current control means connected in parallel to the current limiting means. The xenon lamp driving device according to claim 1, wherein A xenon lamp,
The xenon lamp driving device according to any one of claims 1 to 5, which drives the xenon lamp,
A light source device having: A microscope for observing a sample using light whose intensity is supplied from the light source device according to claim 6. In a diagnostic device for diagnosing tissue,
An excitation unit that excites a tissue by irradiating light whose intensity is supplied from the light source device according to claim 6,
Measuring means for measuring the lifetime of fluorescence or phosphorescence from the excited tissue,
Determining means for determining the state of the tissue based on the measured life,
A diagnostic device comprising: The excitation means excites the tissue with light whose intensity is modulated in a sinusoidal manner, and the measuring means calculates the lifetime from the phase difference between the light having the sinusoidal intensity and the fluorescence or phosphorescence. The diagnostic device according to claim 8, wherein the diagnosis is performed. 9. The diagnostic apparatus according to claim 8, wherein the determining unit determines that the tissue is a tumor when the life span exceeds a threshold. The excitation means excites the sample by illuminating the sample with light supplied from the light source device, and the measuring means determines the position of the sample from the phase difference of fluorescence or phosphorescence from a specific portion of the sample. The diagnostic apparatus according to claim 8, wherein the life is calculated for the microscope. In a diagnostic method for diagnosing a tissue,
Exciting the tissue by irradiating the intensity-modulated light supplied from the light source device according to claim 6;
Measuring the lifetime of fluorescence or phosphorescence from the excited tissue;
Determining the state of the tissue based on the measured life,
A diagnostic method comprising:

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