JP4267897B2 - Xenon lamp driving device, light source device, analyzing device, microscope, diagnostic device and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a xenon lamp driving device that drives a xenon lamp, a light source device that uses a xenon lamp, an analysis device that uses such a light source device, a microscope, a diagnostic device, and a method.
[0002]
[Prior art]
Xenon lamps (Xe lamps) are widely used as light sources for general-purpose spectroscopic analysis and measurement light sources that have continuous wavelengths from the ultraviolet to the near-infrared wavelength region. In particular, almost all Xe lamps are used as light sources for fluorescence measurement, such as fluorescence spectrophotometers and fluorescence detectors for liquid chromatography. In order to light the Xe lamp, a high voltage pulse of tens of thousands of volts is applied between the anode electrode and the cathode electrode 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 cause direct current lighting. Here, the current value is determined by the rating of the lamp.
[0003]
FIG. 10 is a diagram for explaining 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 source 11 to the Xe lamp 13 to turn on the DC lamp.
[0005]
Thus, it has been common knowledge that the conventional Xe lamp is driven in a direct current. However, in all measurement fields including fluorescence spectroscopic analysis, there is an extremely strong demand for modulating emitted light from a light source. For example, in fluorescence spectrometry, when a weak light signal buried in background light is to be acquired by combining a modulation light source and a lock-in amplifier (for example, see Non-Patent Documents 1 and 2), fluorescence phase modulation is performed. This applies to the case where it is desired to obtain the fluorescence lifetime of a sample using the method (see, for example, Non-Patent Documents 3 and 4). Furthermore, not only fluorescence spectrometry but also absorption spectroscopy measurement, it is often desired to modulate the light source for the purpose of improving the signal-to-noise ratio. The same applies to photoacoustic spectroscopic analysis, photothermal lens, photothermal deflection spectroscopic analysis, and the like.
[0006]
Although the purpose is slightly different from that of the above 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 with a very small duty ratio on the order of a repetition frequency of about 100 Hz and a pulse width of several microseconds. Most of its applications are to excite the sample in a delta function and measure the subsequent transient response. For these purposes, the present inventors have proposed a more appropriate method of performing a spark discharge on the order of a repetition rate of about KHz and a pulse width of several nanoseconds for a pulse discharge xenon lamp (for example, non-patent literature). 5, 6, 7, and 8) Applied as a pulse-excited fluorescence lifetime measurement and time-resolved fluorescence detector for liquid chromatography (for example, see Non-Patent Document 9). However, this type of short-time pulse discharge type Xe lamp cannot be used for the purpose of the modulated light source.
[0007]
On the other hand, the laser diode (LD) and the light emitting diode (LED) can be pulsed very easily, and on the other hand, current modulation can also be performed. The present inventors have reported a nanosecond pulse of an LED for a long time, and also proposed a phase modulation type fluorescence lifetime meter using an ultraviolet LED for current modulation (for example, Non-Patent Documents 3 and 4). reference.). However, there are problems of emission wavelength range and emission power, respectively. At present, it is not yet a general-purpose spectroscopic light source. For this reason, it has been strongly desired to develop a method for simply modulating the Xe lamp at an arbitrary frequency. However, it is impossible in principle to pulse the Xe lamp because there is a need to apply a high voltage pulse at the start of lighting. Therefore, it is sufficient that the current can be directly modulated through the Xe lamp for direct current lighting while supplying a bias current, but no such attempt has been made so far.
[0008]
Therefore, in the past, 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 element, an electro-optic element using a nonlinear optical crystal, or the like. It was. However, a mechanical chopper needs to form an image of a light source on the chopper surface, and further to form a light beam after passing through the chopper onto an object such as a sample, resulting in a large apparatus shape (for example, , See Non-Patent Document 10.) The frequency of chopping is about 10 KHz at most. In addition to the chopper and its driver, the overall cost of the optical system and the like for ultraviolet wavelengths also increases. Acousto-optic elements and electro-optic elements can be modulated by an external electrical signal. However, as with choppers, there are problems such as the need for an imaging optical system and the problem of reduced spectral transmittance in the ultraviolet wavelength region. is there. In particular, the electro-optic element has a problem that the price including the peripheral control circuit and the high-voltage power supply becomes very high. In the case of acousto-optic elements, the system becomes expensive and complicated, although not as much as in the case of electro-optic elements. Furthermore, it has been quite complicated in terms of the system configuration to use these together with the conventional DC lighting mode or to easily switch between them.
[0009]
[Non-Patent Document 1]
Takanobu Sato, Hironori Susaki, Tetsuro Iwata, Kentaro Yamamoto, Tamao Kotake, Takashi Inaga, `` Fluorescence detection type NO2 monitoring device using microchip '', IEEJ E, 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 Background Situation”, Opt. 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-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 Light-Emitting Diode,” Rev. 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 Luminescence Characteristics of Self-Propelled Nanosecond Xe Pulsed White Light Source”, Spectroscopic Research, 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 , pp4045-4049, 2000.
[0016]
[Non-Patent Document 8]
T. Iwata, T. Tanaka, T. Araki, T. Uchida, “Externally-Controlled Nanosecond Xe Discharge Lamp Equipped with a Synchronous High-Voltage Power Supply Using an Automobile Ignition Coil”, Rev. Sci. Instrum. , 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 Using a Nanosecond Pulsed Light Source for Detecting Lanthanide-Chelated Compounds,” J. Chromatogr. A, Vol.859 , pp.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 Europium Chelate,” Anal. Chem., Vol.69, No. 10, pp.1861-1865, 1997.
[0019]
[Problems to be solved by the invention]
The present invention has been proposed to solve the above-described problems, and is a xenon lamp driving device that modulates the intensity of light emitted from a xenon lamp, and a xenon lamp is driven using such a xenon lamp driving device. It is an object of the present invention to provide a light source device that performs analysis, an analysis device that uses such a light source device, a microscope, and a diagnostic device and method.
[0020]
[Means for Solving the Problems]
In order to solve the above-described problems, a xenon lamp driving apparatus according to the present invention drives a xenon lamp, and includes a power source that supplies current to the xenon lamp, and a constant current from the power source to the xenon lamp. A first circuit for supplying, a second circuit for supplying a constant bias current and an amplitude-modulated current from the power source to the xenon lamp, and switching means for switching between the first and second circuits. .
[0021]
Preferably, the second circuit includes 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 source has a function of generating a predetermined voltage at the start of lighting of the xenon lamp, and the switching means 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 source to the xenon lamp, and the second circuit connects the current control means in parallel with the current limiting means. It is a thing.
[0027]
Preferably, the first circuit includes first current control means for controlling a current supplied from the power source to the xenon lamp, and the second circuit is supplied from the power source to the xenon lamp. 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 a xenon lamp, and includes a power source for supplying current to the xenon lamp, and when the voltage of the power source exceeds a certain value, the power source supplies the xenon lamp. And a second circuit connected in parallel with the first circuit for supplying a constant bias current and an amplitude-modulated current from the power source to the xenon lamp. 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 source 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]
The light source device according to the present invention includes a xenon lamp and the xenon lamp driving device having any one of the configurations configured to drive the xenon lamp.
[0036]
The microscope according to the present invention observes a sample using light whose intensity is supplied from the light source device.
[0037]
Preferably, the sample is incidentally illuminated with light supplied from the light source device.
[0038]
A diagnostic apparatus according to the present invention is for diagnosing a tissue, and includes excitation means for exciting a tissue by irradiating light whose intensity is supplied from the light source device, and excitation from the excited tissue. Measuring means for measuring the lifetime of fluorescence or phosphorescence, and determining means for determining the state of the tissue based on the measured lifetime.
[0039]
Preferably, the excitation means excites the tissue with light whose intensity is modulated in a sine wave shape, and the measurement means calculates the lifetime from the phase difference between the light having the sine wave intensity and the fluorescence or phosphorescence.
[0040]
Preferably, the determination means determines that the tissue is a tumor when the lifespan exceeds a threshold value.
[0041]
Preferably, the microscope is used, and the excitation unit excites the sample by incident illumination on the sample with light supplied from the light source device, and the measurement unit emits fluorescence or phosphorescence from a specific part of the sample. The lifetime is calculated for the part from the phase difference for.
[0042]
The diagnostic method according to the present invention is a method for diagnosing a tissue, the step of exciting a tissue by irradiating light whose intensity is supplied from a light source device, and fluorescence or fluorescence from the excited tissue. Measuring a phosphorescence lifetime, and determining a state of the tissue based on the measured lifetime.
[0043]
Preferably, the light supplied from the light source device has an intensity modulated in a sine wave shape, and the lifetime is calculated from a phase difference from the fluorescence or phosphorescence.
[0044]
Preferably, when the lifetime of the fluorescence or phosphorescence exceeds a threshold value, it is determined that the tissue is a tumor.
[0045]
Preferably, using the microscope, a predetermined part of the tissue is irradiated with light supplied from the light source device, and the lifetime of fluorescence or phosphorescence is calculated from the phase difference for the part.
[0046]
The analyzer according to the present invention excites the sample by irradiating the light whose intensity is supplied from the light source device, and observes fluorescence or phosphorescence from the excited sample. Based on the analysis of the sample.
[0047]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a xenon lamp (hereinafter referred to as Xe lamp) drive device, light source device, analysis device, microscope, diagnostic device and method according to the present invention will be described in detail below with reference to the drawings.
[0048]
In the present embodiment, a light source device in which an Xe lamp driving device that drives an Xe lamp is combined with an Xe lamp will be described. However, the present invention can also be realized by a single Xe lamp driving device that drives an 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 of the first embodiment includes a power source 11, an 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 when the Xe lamp 13 starts lighting or when the DC lighting is turned on. Yes.
[0051]
The power supply 11 includes a starter that supplies a current to the Xe lamp 13 and generates a high voltage pulse when the Xe lamp 13 starts to light. 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 the Xe lamp 13 is dc-lit, the first switch SW1 is turned on and the second switch SW2 is turned off, and a constant current is supplied from the power source 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 source 11 and the Xe lamp 13, the second switch SW2, the first MOSFET Q1, and the first resistor R1 pass current from the power source 11 to the xenon lamp 13 when modulating the intensity of light emitted from the Xe lamp 13. A second circuit to be supplied is configured. The 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 of 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 a 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 has a bias current corresponding to the bias voltage set by the second and third resistors R2 and R3 and the alternating current component of the input signal to the input terminal S input from the coupling capacitor C. The modulation current is controlled to flow as a drain current.
[0057]
Here, the bias current is a constant current of, for example, several A required for maintaining an arc in the Xe lamp 13. The bias current is set by the values of the first to third resistors R1, R2, and 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. For example, a sine wave having a desired frequency for modulating the intensity of light is input to the input terminal S.
[0059]
Thus, the Xe lamp 13 is controlled in arc intensity by the bias current, and the intensity of light emitted by the modulation current corresponding to the input signal to the input terminal S is modulated.
[0060]
The following procedure is required until light whose intensity is modulated is emitted from the light source device of the first embodiment.
[0061]
First, the first switch SW1 is turned on, the second switch SW2 is turned off, a high voltage pulse is supplied from the starter provided in the power supply 11 to the Xe lamp 13 via the first circuit, and the Xe lamp 13 is turned on. After the Xe lamp 13 is lit by the starter, a constant current is supplied from the power source 11 to the Xe lamp 13 through the first circuit until the state of the Xe lamp 13 is stabilized, and the DC lighting is maintained.
[0062]
When a predetermined time elapses after the Xe lamp 13 is turned on and the state of the Xe lamp 13 is stabilized, the second switch SW2 is turned on, the first switch SW1 is turned off, and the second power source 11 sends the second switch SW1 to the Xe lamp 13. Current is supplied through the circuit. 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 with 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. At this time, the second switch SW2 is turned off. Has been. Therefore, there is no possibility that the first MOSFET Q1 is destroyed by the application of the high voltage pulse. As described above, in the light source device according to the present embodiment, it is possible to safely and reliably execute the start-up of the Xe lamp 13, the direct-current lighting, and the lighting with the light intensity varied.
[0064]
FIG. 2 is a time chart showing 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]
A 35 W type Xe lamp 13 (L2193, Hamamatsu Photonics) and a first MOSFET Q1 (BUK454-200B, Philips Semiconductors) were used for the light source device.
[0067]
Here, the waveform of the source voltage of the first MOSFET Q1 when a signal having a frequency of 100 kHz is input to the input terminal S and current modulation is performed, and the emitted light from the Xe lamp 13 are converted into a photomultiplier tube (U7400 Hamamatsu Photonics, The waveform of an oscilloscope that received light at a load of 50Ω was shown. The degree of modulation at this time was about 25%. The maximum value of the degree of modulation 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 average drain current of the first MOSFET Q1 and the peak voltage of the sine wave applied to the input terminal S are optimized, the degree of modulation can be further improved to about 50% (Nippon Optical Co., Ltd.). , Optics Japan 2002, Abstracts of lectures).
[0068]
FIG. 3 is a diagram illustrating a configuration of the light source device according to the second embodiment.
[0069]
The light source device of the second embodiment is obtained by inserting a resistor (current limiting means) between the first switch SW1 and the power source 11 in the light source device of the first embodiment shown in FIG.
[0070]
In the second embodiment, the power source 11, the Xe lamp 13, the first switch SW 1, and the resistor R supply the current from the power source 11 to the Xe lamp 13 when the Xe lamp 13 starts lighting or DC lighting. The circuit is configured.
[0071]
Further, the light emitted from the Xe lamp 13 by 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. The second circuit is configured to supply current from the power supply 11 to the Xe lamp 13 when the intensity of light is modulated. That is, the second circuit is obtained by connecting the second switch SW2, the first MOSFET Q1, and the first resistor R1 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 DC lighting, the first switch SW1 is turned on and the second switch SW2 is turned off. Supply current through the circuit. When modulating the intensity of the light emitted from the Xe lamp 13, the first and second switches SW1 and SW2 are turned on, and a current is supplied from the power source 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]
Thus, 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 system because 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, the power consumption, the depth of modulation, and the like.
[0075]
FIG. 4 is a diagram illustrating a configuration of the light source device according to the third embodiment.
[0076]
The light source device of the third embodiment is the same as the light source device of the second embodiment shown in FIG. 3 except that the first switch SW1 and the resistor R are connected to the third switch SW3 and the second MOSFET (second MOSFET). Current control means) Q2 and a fifth resistor R5 are connected in parallel. The light source device of the third embodiment also has sixth and seventh resistors R6 and R7 that set a bias voltage to be 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 the Xe lamp. A first circuit is configured to supply current from the power source 11 to the Xe lamp 13 at the start of lighting 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. The second circuit is configured to supply current from the power source 11 to the Xe lamp 13 when modulating the intensity of 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 when the Xe lamp 13 is dc-lit. The third switch SW1, SW3 is turned on, the second switch SW2 is turned off, and a current is supplied from the power supply 11 to the Xe lamp 13 via the first circuit.
[0080]
Here, when the lighting of the Xe lamp 13 is started, the second and third switches SW2 and SW3 are turned off because the first and second MOSFETs Q1 and Q2 are not damaged by a high voltage pulse by a starter provided in the power supply 11. It is for doing so.
[0081]
When the intensity of light emitted from the Xe lamp 13 is modulated, the first and second switches SW1 and SW2 are turned on, the third switch SW3 is turned off, and a second circuit is connected from the power source to the Xe lamp 13. Current is supplied through.
[0082]
In the third embodiment, the current supplied to the Xe lamp 13 via the first circuit when the Xe lamp 13 is dc-lit can be controlled by the second MOSFET Q2. That is, the first and third switches SW1 and SW3 are turned on at the time of DC lighting, and the bias voltage of the second MOSFET Q2 is set by the sixth and seventh resistors R6 and R7. The drain current of MOSFET Q2 can be controlled. Therefore, the current is controlled by a parallel circuit of the first switch SW1, 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 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 the light source device according to the fourth embodiment.
[0085]
The light source device according to the fourth embodiment includes a photodiode 15 that detects light emitted from the Xe lamp 13 and a signal input from the photodiode 15 in the light source device according to the third embodiment illustrated in FIG. And a control unit 19 that performs control based on the signal input from the amplifier 17 are added.
[0086]
Except for these additional elements, the light source device of the fourth embodiment is the same as that of the above-described third embodiment. However, in the fourth embodiment, the second circuit for supplying a current from the power source 11 to the Xe lamp 13 when modulating the intensity of the light emitted from the Xe lamp 13 includes the power source 11 and the Xe lamp 13; By 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, the third switch SW3, the second MOSFET Q2 and the 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]
The controller 19 reduces the gate voltage of the second MOSFET Q2 to decrease the drain current when the intensity of the light emitted from the Xe lamp 13 is large, and increases the gate voltage of the second MOSFET Q2 when the intensity of light is small. Increase drain current. Control by feedback of the intensity of light emitted from the Xe lamp 13 is suitable for measurement of an excitation spectrum in a fluorescence spectrophotometer.
[0089]
FIG. 6 is a diagram illustrating a configuration of the light source device according to the fifth embodiment.
[0090]
In the light source device of the fifth embodiment, in the light source device of the first embodiment, an LC circuit 21 including a coil L and a capacitor C is provided in a path from the power source 11 to the Xe lamp 13 so that it can be inserted by switching. 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 light or when the DC lighting is performed. As a result, a high voltage pulse can be supplied to the Xe lamp 13 from the starter of the power source 11 without being disturbed 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, a bias component, which is a DC component, is supplied from the power source 11 to the Xe lamp 13 via the coil L, and the AC component modulation current is bypassed by the capacitor C.
[0093]
In the fifth embodiment, since the modulation current that modulates the intensity of the light emitted from the Xe lamp 13 is bypassed by the power supply 11, the loss of the AC component is small. Since the loss of such 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 the light source device according to the sixth embodiment.
[0095]
The light source device of the sixth embodiment is the same as the light source device of the second embodiment except that the first and second switches SW1 and SW2 are removed and the resistor R is replaced by a surge absorber (voltage sensing means) SA. is there. The surge absorber SA has a property of conducting when a voltage of a predetermined value or more is applied, and can be substituted by a zener diode having a large current capacity, for example.
[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 is turned on, and current flows through the surge absorber SA. For this reason, there is no fear of damage by applying a high voltage pulse to the first MOSFET Q1.
[0097]
When the direct current lighting of the Xe lamp 13 or the intensity of light emitted from the Xe lamp 13 is modulated, the voltage applied to the surge absorber 13 is below a predetermined voltage, the surge absorber 13 is not conducted, and the current is 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 the first and second switches SW1 and SW2 in the first embodiment. It is easy to operate and reliable.
[0099]
FIG. 8 is a diagram showing a configuration of an epi-illumination type fluorescence microscope that constitutes the biological tissue diagnostic apparatus.
[0100]
An epi-illumination 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 lens inside a casing 51. 59 and a photomultiplier tube (PMT) 60.
[0101]
The epi-illumination fluorescence microscope 50 is supplied with light of which intensity is modulated from the light source device 40, illuminates the sample, and observes the excited fluorescence. Light incident from the side of the housing 50 onto the epi-fluorescence microscope 50 from the light source device 40 is turned by a dichroic beam splitter 57 in the housing 50, and the sample on the sample stage 55 is passed through the objective lens 56. Use epi-illumination. The sample is excited by this illumination and emits fluorescence.
[0102]
The fluorescence emitted from the sample is observed as an image through the objective lens 56, the beam splitter 57, the prism 58 and the eyepiece lens 59. Further, part of the fluorescence transmitted through the beam splitter 57 is detected as an electric signal by the photomultiplier tube 60.
[0103]
Illumination from the light source 52 that enters 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 in this way is irradiated with light whose intensity is supplied from the light source device 40. And the lifetime of the fluorescence excited by this light irradiation is measured. Light having a sinusoidal intensity modulated 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 fluorescence is calculated from this phase difference.
[0105]
The epi-illumination fluorescence microscope 50 of this embodiment has a simple structure, a small size, and is easy to handle. According to this epi-illumination type fluorescence microscope 50, the fluorescence lifetime of a sample can be measured quickly and easily without damaging a sample such as a clinical sample.
[0106]
In addition to the epi-illumination fluorescence microscope 50, the biological tissue diagnostic apparatus is excited by the above-described light source device that supplies the epi-illumination fluorescence microscope 50 with light whose intensity is modulated, the light with modulated intensity, and the light. A computer which is supplied with signals observing fluorescence and determines the state of the tissue based on a predetermined algorithm from the phase difference between these signals is provided. This computer determines a tissue according to the following method as a method for diagnosing a living tissue.
[0107]
FIG. 9 is a diagram for explaining a diagnostic method for diagnosing a biological tissue using the biological tissue diagnostic apparatus.
[0108]
This diagnostic method irradiates a tissue such as a clinical sample with light s1 whose intensity is sinusoidally modulated from the light source device described above. Then, the phase difference between the fluorescence s2 and s3 having sinusoidal intensity emitted from the tissue excited by the light irradiation and the irradiated light s1 is measured. Then, the fluorescence lifetime is calculated from the phase difference, and when the lifetime exceeds the threshold, the tissue is determined to be a tumor, and when the threshold is not exceeded, it is determined to be normal.
[0109]
More details are as follows. A curve s1 in the figure shows a temporal change in the intensity of the excitation light having a sinusoidal intensity supplied from the light source device. Curves s2 and s3 in the figure show temporal changes in the intensity of fluorescence excited by excitation light having the intensity change of the curve s1.
[0110]
Tumors are identified 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 the curve s2, but the fluorescence emitted from the tumor tissue has a relatively large delay with respect to the excitation light s1 as shown by the curve s3. . The curve s3 is delayed by the phase difference θ with respect to the curve s2.
[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 from the phase difference is determined, and the lifetime is obtained based on this delay time. Then, it is identified as a tumor when the fluorescence lifetime exceeds a predetermined threshold, and as normal when it does not exceed the predetermined threshold.
[0112]
As described above, by using the light with the modulated intensity emitted from the light source, it is possible to easily diagnose whether the tissue is a tumor or normal. Further, by using the epifluorescence microscope for this diagnosis, the sample can be easily diagnosed.
[0113]
In the above-described embodiment, the fluorescence has been described. However, the present invention can be applied to phosphorescence as well as the fluorescence.
[0114]
As described above, according to the present embodiment, an inexpensive and simple modulated Xe light source ranging from the ultraviolet to the near-infrared wavelength region can be realized. The inventor of the present invention has realized direct current modulation of a Xe lamp for direct current lighting, which has been considered impossible in the past or has not been considered at all. The modulation circuit is extremely simple, inexpensive and compact, and has the excellent feature that it can be easily switched or used together with no change in the optical system compared to the conventional Xe lamp for direct current lighting.
[0115]
The proposed current modulation Xe lamp can be used in the following equipment. Light source for microspectroscopy, fluorescence detector for liquid chromatography, general-purpose fluorescence spectrophotometer, visible / ultraviolet absorption spectrophotometer, photoacoustic light source, continuous light source for flash photolysis, etc. Further, if the modulation frequency can be increased, it has great utility as a light source for a phase modulation type fluorescence lifetime meter.
[0116]
In addition, this Embodiment shows the specific example of this invention, and this invention is not limited to this. It will be apparent to those skilled in the art that design changes can be made 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 the 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 Second MOSFET
R resistance
R1 first resistor
R2 second resistance
R3 Third resistance
S input terminal
SW1 first switch
SW2 second switch

Claims (11)

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 source to the xenon lamp;
A second circuit for supplying a constant bias current and an amplitude-modulated current from the power source to the xenon lamp;
Switching means for switching between the first and second circuits;
Have
The xenon lamp driving apparatus, wherein the second circuit has current control means for controlling a current supplied to the xenon lamp, and the current control means is a MOSFET .   2. The xenon lamp drive according to claim 1, wherein the power source 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 is obtained by inserting the current control means in series with the first circuit.   The first circuit includes current limiting means for limiting a current supplied from the power source to the xenon lamp, and the second circuit includes the current control means connected in parallel to the current limiting means. The xenon lamp driving apparatus according to claim 1, wherein the xenon lamp driving apparatus is provided. A xenon lamp,
The xenon lamp driving device according to any one of claims 1 to 4 , which drives the xenon lamp;
A light source device. A microscope for observing a sample using light whose intensity is supplied from the light source device according to claim 5 . In a diagnostic device for diagnosing tissue,
Excitation means for exciting the tissue by irradiating light whose intensity is supplied from the light source device according to claim 5 ;
Measuring means for measuring the lifetime of fluorescence or phosphorescence from the excited tissue;
Determination means for determining the state of the tissue based on the measured lifetime;
A diagnostic apparatus comprising: The excitation means excites the tissue with light whose intensity is modulated sinusoidally, and the measuring means calculates the lifetime from the phase difference between the light with sinusoidal intensity and the fluorescence or phosphorescence. The diagnostic device according to claim 7 . 8. The diagnostic apparatus according to claim 7 , wherein the determination unit determines that the tissue is a tumor when the lifetime exceeds a threshold value. The excitation means excites the tissue by epi-illuminating the tissue with light supplied from the light source device, and the measurement means calculates the phase difference from fluorescence or phosphorescence from a specific part of the sample tissue. The diagnostic apparatus according to claim 7 , wherein the lifetime is calculated for a part. 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 5 ;
Measuring the lifetime of fluorescence or phosphorescence from the excited tissue;
Determining the state of the tissue based on the measured lifetime;
A diagnostic method characterized by comprising:

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