Light source device

Abstract

A light source device according to one embodiment of the present invention generates wavelength-swept light, and is equipped with a pulsed light source, a pulse stretcher, and a fan device. The pulsed light source generates pulsed light including a continuous spectrum. The pulse stretcher is configured so as to stretch the pulsed light on the time axis and generate the wavelength-swept light. The fan device supplies air to the pulse stretcher. In this way, it becomes possible to suppress temperature changes in the pulse stretcher, and to stably output wavelength-swept light.

Description

light source device

[0001] The present invention relates to a light source device.

[0002] Spectroscopic analysis is widely used for the component analysis and inspection of objects. In spectroscopic analysis, an object is irradiated with irradiating light, and the spectrum of the resulting object light is measured. Then, optical characteristics such as reflectance characteristics (wavelength dependence) or transmittance characteristics can be obtained based on the relationship between the spectrum of the object light and the spectrum of the irradiating light.

[0003] Wavelength-swept spectroscopy is known as one of the methods for measuring optical properties. In a wavelength-swept spectrometer, wavelength-swept light, whose wavelength changes over time, is generated and irradiated onto the object to be inspected. The wavelength-swept light is a pulse or pulse train in which time and wavelength have a one-to-one relationship. The time waveform of the light obtained by irradiating the object to be inspected with the wavelength-swept light is detected by a photodetector. The output waveform of the photodetector represents a spectrum in which the time axis corresponds to the wavelength.

[0004] Japanese Patent Application Laid-Open Nos. 2003-129999 and 2003-129999 disclose wavelength sweep type spectroscopic measurement devices.

[0005] JP 2020-159971 A JP 2020-159973 A

[0006] In a wavelength sweeping spectrometer, it is important to stably output wavelength swept light.

[0007] In view of the above circumstances, an object of the present invention is to provide a light source device capable of stably outputting wavelength swept light.

[0008] To achieve the above object, a light source device according to one aspect of the present invention is a light source device that generates wavelength-swept light, and includes a pulsed light source, a pulse stretcher, and an air blower. The pulsed light source generates pulsed light having a continuous spectrum. The pulse stretcher is configured to stretch the pulsed light on a time axis to generate the wavelength-swept light. The air blower supplies air to the pulse stretcher.

[0009] In this light source device, air is supplied to the pulse stretcher by a blower, which makes it possible to suppress temperature changes in the pulse stretcher and to stably output wavelength-swept light.

[0010] The light source device may further include a housing having an inlet through which the air flows and an outlet through which the air flows out, and accommodating the pulse stretcher in an internal space. In this case, the air blower may supply the air to the internal space through the inlet.

[0011] The housing may house the pulsed light source in the internal space.

[0012] The pulse stretcher may be disposed upstream of the pulse light source with respect to a flow path of the air flowing in from the inlet.

[0013] The internal space of the housing may have a multi-layer structure consisting of a plurality of floors. In this case, the pulse light source and the pulse stretcher may each be disposed on one of the plurality of floors. The air blower may supply the air to the floor on which the pulse stretcher is disposed.

[0014] The pulse light source and the pulse stretcher may be disposed in different layers among the plurality of layers.

[0015] Among the plurality of stories, a story on which the pulse light source is arranged and a story on which the pulse stretcher is arranged may be spatially continuous, in which case the air blower may supply the air to the story on which the pulse stretcher is arranged or the story on which the pulse light source is arranged.

[0016] The multi-layer structure may be a structure in which the plurality of layers are stacked along the height direction of the light source device.

[0017] The inlet may be positioned higher than the outlet in a height direction of the light source device.

[0018] The housing may have a top surface that constitutes a ceiling of the highest floor among the plurality of floors. In this case, the air inlet may be formed on the top surface. The air blower may supply the air downward in the height direction through the air inlet.

[0019] The blower may be arranged on the top surface.

[0020] The pulse stretcher may be arranged in the top layer. In this case, the pulse light source may be arranged in a layer immediately below the top layer. The top layer and the layer immediately below the top layer may be spatially continuous.

[0021] The light source device may further include an air conditioner that generates temperature-adjusted controlled air. In this case, the air blower may supply the controlled air to the pulse stretcher.

[0022] The internal space of the housing may have a multi-layer structure including a plurality of levels, in which case the pulse light source, the pulse stretcher, and the air conditioner may be disposed in different levels among the plurality of levels.

[0023] The multi-layer structure may be a structure in which the plurality of layers are stacked along a height direction of the light source device, and in this case, the air conditioner may be arranged on a layer lower than the pulse light source and the pulse stretcher in the height direction of the light source device.

[0024] The air conditioner may have a temperature sensor provided near the inlet.

[0025] The temperature sensor may be located closer to the pulse stretcher than the pulsed light source.

[0026] The internal space of the housing may be configured as a heat-insulating space.

[0027] The blower may supply a mixture of the air discharged from the outlet and the control air to the pulse stretcher.

[0028] The air volume of the blower may be greater than the air volume of the air conditioner.

[0029] The air exhausted from the pulse light source may be exhausted to the outside of the housing without passing through a floor on which the pulse stretcher is arranged.

[0030] The blower may be a fan filter unit.

[0031] The pulse stretcher may include an arrayed waveguide grating that spatially divides the pulsed light emitted from the pulsed light source into a plurality of beams according to wavelengths, and a plurality of fibers having different optical path lengths corresponding to the plurality of beams.

[0032] Any combination of the above elements, or mutual substitution of elements or expressions between methods, devices, systems, etc., are also valid aspects of the present invention or the present disclosure. Furthermore, the description in this section (Means for Solving the Problems) does not explain all essential features of the present invention, and therefore, subcombinations of the described features may also constitute the present invention.

[0033] As described above, according to the present invention, it is possible to stably output wavelength swept light. Note that the effects described here are not necessarily limited to those described herein, and any of the effects described in this disclosure may be employed.

[0034] FIG. 3 is a schematic diagram for explaining an overview of a wavelength sweeping spectroscopic measurement device. FIG. 4 is a schematic diagram showing a specific configuration example of the spectroscopic measurement device. FIG. 5 is a diagram showing wavelength swept light. FIG. 6 is a schematic diagram for explaining spectroscopy by the spectroscopic measurement device shown in FIG. 2. FIG. 7 is a block diagram showing a basic configuration example of a light source device according to an embodiment. FIG. 8 is a perspective view showing a light source device exemplified as Configuration Example 1. FIG. 9 is a perspective view showing a light source device exemplified as Configuration Example 2. FIG. 10 is a perspective view showing a light source device exemplified as Configuration Example 3. FIG. 11 is a perspective view showing a light source device exemplified as Configuration Example 4. FIG. 12 is a perspective view showing a light source device exemplified as Configuration Example 5. FIG. 13 is a perspective view showing a light source device exemplified as Configuration Example 6.

[0035] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0036] [Outline of Wavelength Swept Spectroscopic Measurement Apparatus] Fig. 1 is a schematic diagram for explaining an outline of a wavelength swept spectroscopic measurement apparatus. The spectroscopic measurement apparatus is also called a spectroscope, a spectroscopic device, a spectroscopic inspection device, etc.

[0037] The spectroscopic measurement device 1 shown in FIG. 1 includes a light source device 2, a spectroscopic head 3, and a processing device 4.

[0038] The light source device 2 generates wavelength-swept light L1. The wavelength-swept light L1 is guided to the spectroscopic head 3. The irradiation optical system 5 of the spectroscopic head 3 irradiates the wavelength-swept light L1 onto a sample 6. The first photodetector 7 detects light (object light) L2 obtained as a result of irradiating the sample 6 with the wavelength-swept light L1. The object light L2 may be reflected light or transmitted light from the sample 6.

[0039] In the irradiation optical system 5, a part of the wavelength swept light L1 is branched off as a reference light L3. A second light receiver 8 measures the reference light L3.

[0040] The first detection signal S1 generated by the first light receiver 7 and the second detection signal S2 generated by the second light receiver 8 are supplied to the arithmetic processing unit 4.

[0041] The object light L2 and the reference light L3 inherit the one-to-one time-wavelength correspondence of the wavelength swept light L1. Therefore, the time waveform of the first detection signal S1 can be converted into the spectrum of the object light L2 by converting the time axis into wavelength.

[0042] Similarly, the time waveform of the second detection signal S2 can be converted into the spectrum of the reference light L3 by converting the time axis into wavelength. The calculation processing device 4 calculates, for example, the ratio of the object light L2 to the reference light L3 for each corresponding wavelength, and measures the spectral characteristics (reflectance, transmittance, etc.) of the sample 6.

[0043] [Specific Configuration Example of Spectroscopic Measurement Apparatus] Fig. 2 is a schematic diagram showing a specific configuration example of a spectroscopic measurement apparatus 10. The spectroscopic measurement apparatus 10 shown in Fig. 2 includes a light source device 11, an irradiation optical system 12, a light receiving device 13, and a processing unit 14.

[0044] The light source device 11 generates wavelength-swept light L1 whose wavelength changes over time. The wavelength-swept light L1 has a one-to-one correspondence between time and wavelength. This means that the wavelength-swept light L1 has a "unique wavelength."

[0045] The light source device 11 includes a pulse light source 15 and a pulse stretcher 16 .

[0046] The pulsed light source 15 emits broadband pulsed light L1a having a broad, continuous spectrum. The spectrum of the broadband pulsed light L1a is continuous over a wavelength range of at least 10 nm, preferably 50 nm, and more preferably 100 nm, for example, in the range of 900 nm to 1300 nm. The width of the wavelength range of the broadband pulsed light L1a needs only to cover the wavelength range required for spectroscopy.

[0047] For example, the pulsed light source 15 may include an ultrashort pulsed laser and a nonlinear element. Examples of the ultrashort pulsed laser include a gain-switched laser, a microchip laser, and a fiber laser.

[0048] Nonlinear elements use nonlinear phenomena to further broaden the spectral width of the ultrashort pulses generated by ultrashort pulse lasers. Fibers are suitable as nonlinear elements, and for example, photonic crystal fibers or other nonlinear fibers can be used. Single-mode fibers are preferred, but multi-mode fibers can also be used as long as they exhibit sufficient nonlinearity.

[0049] The broadband pulsed light L1a output from the nonlinear element has a pulse width on the order of femtoseconds to nanoseconds. Note that other broadband pulsed light sources such as an SLD (Superluminescent Diode) light source may also be used as the pulsed light source 15.

[0050] The pulse stretcher 16 stretches the pulse width of the broadband pulsed light L1a and outputs the wavelength swept light L1. The pulse stretcher 16 includes a splitter (demultiplexer) 17, a delay line 18, and a coupler 19.

[0051] The splitter 17 splits the broadband pulsed light L1a into multiple n beams (n≧2) according to wavelengths. The configuration of the splitter 17 is not particularly limited, but it can be configured, for example, by an arrayed waveguide grating (AWG). A wavelength selection filter that selects a wavelength band to be used for spectroscopic analysis from the spectral components contained in the broadband pulsed light L1a may be inserted between the splitter 17 and the pulsed light source 15.

[0052] The delay line 18 applies different delays to the light (split light) on the multiple paths. For example, the delay line 18 includes multiple fibers FB1 to FBn with different optical path lengths.

[0053] Assume that the broadband pulsed light L1a before splitting is a positive chirp pulse (up-chirp pulse) whose frequency increases (wavelength shortens) over time. In this case, the leading edge of the pulse contains a component with the longest wavelength λ1, and the trailing edge of the pulse contains a component with the shortest wavelength λn.

[0054] The multiple fibers FB1 to FBn have different optical path lengths l1 to ln. If λ1 is the longest wavelength and λn is the shortest wavelength, then the wavelength swept light L1 can be made to have the same positive chirped pulse as the broadband pulsed light L1a by satisfying the relationship l1<l2< ... <ln. As an example, when n = 20, the optical path lengths l1 to l20 of the 20 fibers FB may increase in 1-m increments from 1 m to 20 m.

[0055] The fibers FB1 to FBn do not need to have different group delay characteristics for each wavelength, and the same fiber (fibers with the same core / clad material) can be used. In this sense, the fiber FB can be a multimode fiber, which is advantageous in that unintended nonlinear optical effects can be prevented.

[0056] The coupler 19 recombines the multiple beams to which different delays have been imparted by the delay line 18. For example, the coupler 19 may be an AWG that combines n beams. Alternatively, a bundle fiber or a multi-core fiber may be used as the delay line 18. The spatially recombined light is output as wavelength-swept light L1.

[0057] In this embodiment, the splitter 17 is configured as an embodiment of an arrayed waveguide grating according to the present invention, which spatially splits pulsed light emitted from a pulsed light source into multiple beams according to wavelength, and the multiple fibers FB1 to FBn are configured as an embodiment of a multiple fibers having different optical path lengths corresponding to the multiple beams according to the present invention.

[0058] 3 is a diagram showing the wavelength swept light L1, in which the upper part shows the intensity (time waveform) IWS(t) of the wavelength swept light L1, and the lower part shows the change in the wavelength λ of the wavelength swept light L1 over time.

[0059] In this example, the wavelength-swept light L1 is a single pulse of light, with a dominant wavelength λ1 at its leading edge and λn at its trailing edge, and the wavelength changes over time between λ1 and λn within one pulse. In this example, the wavelength-swept light L1 is a positive chirp pulse (λ1>λn) whose frequency increases over time, in other words, whose wavelength shortens over time.

[0060] The wavelength swept light L1 may be a negative chirp pulse whose wavelength increases with time (λ1<λn), or may be a pulse train consisting of pulses (wave packets) isolated in time for each wavelength.

[0061] Returning to Fig. 2, the irradiation optical system 12 irradiates the wavelength swept light L1 onto the sample 6. The irradiation optical system 12 and the light source device 11 may be coupled via an optical fiber.

[0062] The irradiation optical system 12 includes a lens optical system 20, a beam splitter 21, and a mirror 22. The lens optical system 20 focuses the wavelength swept light L1 onto the surface of the sample 6 (sample surface) with an appropriate beam size.

[0063] The beam splitter 21 directs a portion of the wavelength swept light L1 toward the sample 6. The beam splitter 21 also extracts a portion of the wavelength swept light L1 as a reference light L3. The mirror 22 directs the reference light L3 toward the light receiving device 13.

[0064] The light receiving device 13 includes a first light receiver 23, a second light receiver 24, and A / D converters 25 and 26. The first light receiver 23 detects object light L2 obtained by irradiating the wavelength swept light L1 onto the sample 6. The object light L2 may be reflected light or transmitted light.

[0065] The A / D converter 25 converts the output signal S1 of the first photodetector 23 into a digital signal D1. The second photodetector 24 detects the reference light L3. The A / D converter 26 converts the output signal S2 of the second photodetector 24 into a digital signal D2. The time waveform IOBJ(t) of the object light L2 indicated by the digital signal D1 and the time waveform IREF(t) of the reference light L3 indicated by the digital signal D2 are input into the calculation processing device 14.

[0066] In wavelength-swept spectroscopy, there is a one-to-one correspondence between time and wavelength in the wavelength-swept light L1. This correspondence is naturally also held by the reference light L3 and is also inherited by the object light L2.

[0067] Using this correspondence between time and wavelength, the arithmetic processing device 14 converts the time waveform IOBJ(t) of the object light L2 into a frequency domain spectrum IOBJ(λ). The arithmetic processing device 14 also converts the time waveform IREF(t) of the reference light L3 into a spectrum and appropriately scales it to calculate the reference spectrum IREF(λ).

[0068] The processing of the arithmetic processing device 14 is not particularly limited, but as an example, the arithmetic processing device 14 can calculate the transmittance T(λ) or reflectance R(λ) of the object OBJ (sample 6) based on the reference spectrum IREF(λ) and the spectrum IOBJ(λ) of the object light L2. T(λ) = IOBJ(λ) / IREF(λ) R(λ) = IOBJ(λ) / IREF(λ)

[0069] 4 is a schematic diagram illustrating spectroscopy by the spectroscopic measurement device 10 shown in FIG. 2. As described above, the wavelength swept light L1 has a one-to-one correspondence between time t and wavelength λ. Therefore, the time waveform IREF(t) of the wavelength swept light L1 can be converted into a frequency domain spectrum IREF(λ).

[0070] The time waveform IOBJ(t) of the object light L2 also has a one-to-one correspondence between time t and wavelength λ. Therefore, the calculation processing device 14 can convert the waveform IOBJ(t) of the object light L2 indicated by the output of the light receiving device 13 into the spectrum IOBJ(λ) of the object light L2.

[0071] The calculation processing device 14 can calculate the transmission spectrum T(λ) of the object OBJ (sample 6) based on the ratio IOBJ(λ) / IREF(λ) of the two spectra IOBJ(λ) and IREF(λ).

[0072] The relationship between wavelength λ and time t in wavelength swept light L1 is expressed by the function λ = f(t). Most simply, wavelength λ changes linearly with time t according to a linear function. When the time waveform IOBJ(t) of object light L2 drops at a certain time tx, the transmission spectrum T(λ) has an absorption spectrum at wavelength λx = f(tx).

[0073] Note that the processing in the calculation processing device 14 is not limited to this. After calculating the ratio T(t) = IOBJ(t) / IREF(t) of two time waveforms IOBJ(t) and IREF(t), the transmission spectrum T(λ) may be calculated by converting the variable t of this time waveform T(t) to λ.

[0074] [Considerations regarding stable output of wavelength swept light L1] The present inventors have newly discovered that the measurement accuracy of the spectroscopic measurement devices 1 and 10 illustrated in Figures 1 and 2 is strongly affected by fluctuations in the wavelength swept light L1, which is the output of the light source devices 2 and 11.

[0075] That is, the inventor has newly discovered that in the spectroscopic measurement devices 1 and 10, it is possible to improve measurement accuracy by suppressing fluctuations in the wavelength swept light L1 output by the light source devices 2 and 11 and stably outputting the wavelength swept light L1.

[0076] The inventors have conducted extensive research to achieve stable output of wavelength swept light L1 from the light source devices 2 and 11.

[0077] The pulse light source 15 shown in Fig. 2 is typically configured such that the components of the pulse light source 15 are housed in a single housing (see the pulse light source 15 in Fig. 6). On the other hand, the pulse stretcher 16 is typically configured such that the components of the pulse stretcher 16 (such as the splitter 17, delay line 18, and coupler 19) are mounted on a support member 40 (see Fig. 6). The support member 40 may be, for example, an optical surface plate.

[0078] The inventors have examined the pulse stretcher 16 mounted on the support member 40 and have newly discovered that misalignment caused by temperature changes has a significant impact on the intensity, spectrum, and delay amount for each wavelength of the wavelength-swept light L1.

[0079] The present inventors have newly discovered that by suppressing temperature changes in the pulse stretcher 16, it is possible to suppress fluctuations in the characteristics of the pulse stretcher 16, and thus to suppress fluctuations in the intensity, amplitude spectrum, phase spectrum, etc. of the wavelength swept light L1. In other words, it has newly discovered that by suppressing temperature changes in the pulse stretcher 16, it is possible to achieve a stable output of the wavelength swept light L1.

[0080] The light source device according to the present invention, which was newly devised based on the above-mentioned findings of the inventors, will now be described in detail.

[0081] 5 is a block diagram showing an example of the basic configuration of a light source device 28 according to one embodiment of the present invention. The light source device 28 generates wavelength swept light L1, and includes a pulse light source 15, a pulse stretcher 16, and an air blower 29.

[0082] As described above, the pulsed light source 15 generates the broadband pulsed light L1a having a broadband continuous spectrum. The pulse stretcher 16 is configured to stretch the broadband pulsed light L1a on the time axis to generate the wavelength-swept light L1.

[0083] The air blower 29 supplies air to the pulse stretcher 16. This makes it possible to suppress temperature changes in the pulse stretcher 16, and to achieve a stable output of the wavelength swept light L1.

[0084] For example, an FFU (fan filter unit) can be used as the blower 29. The FFU has a built-in filter and fan, and can remove dirt, dust, and the like from the air and supply clean air to the pulse stretcher 16. Of course, the specific configuration of the blower 29 is not limited, and any configuration different from an FFU can be adopted.

[0085] For example, air outside the light source device 28 (air in the environment where the light source device 28 is placed) may be used as the air supplied to the pulse stretcher 16 by the blower device 29. For example, the light source device 28 is placed in a clean room or the like where the air cleanliness and temperature are adjusted. In this case, the blower device 29 can supply air whose air cleanliness and temperature have been adjusted to the pulse stretcher 16.

[0086] Of course, the effect of suppressing temperature changes in the pulse stretcher 16 can also be achieved by supplying air from an environment in which the air cleanliness and temperature are not adjusted to the pulse stretcher 16.

[0087] Alternatively, an air conditioner capable of generating temperature-adjusted controlled air may be prepared and connected to the blower 29. The blower 29 may then supply the temperature-adjusted controlled air to the pulse stretcher 16. This can improve the effect of suppressing temperature changes in the pulse stretcher 16.

[0088] Alternatively, air containing a predetermined type of gas, air with adjusted components, or the like can be supplied to the pulse stretcher 16 .

[0089] [Specific Configuration Examples of Light Source Device] As specific configuration examples 1 to 6 of the light source device 28, light source devices 28A to 28F will be described.

[0090] 6 is a perspective view showing a light source device 28A illustrated as Configuration Example 1. In the drawing, dashed arrows schematically indicate air flows, and solid arrows schematically indicate light paths.

[0091] The light source device 28A includes a pulse light source 15, a pulse stretcher 16, an FFU 31 that functions as a blower device 29, and a housing part 32.

[0092] 6, the housing 32 has an approximate rectangular parallelepiped outer shape. The housing 32 has a bottom surface 33a and a top surface 33b that faces the bottom surface 33a in the height direction of the light source device 28A (the up-down direction in the drawing). The housing 32 also has four side surfaces 33c to 33f.

[0093] The bottom surface 33a is the lowest surface of the light source device 28A in the height direction, and is the surface closest to the placement surface when the light source device 28A is placed. The top surface 33b is the highest surface of the light source device 28A in the height direction.

[0094] The side surface 33c is the front surface in Fig. 6 and may hereinafter be referred to as the front surface 33c using the same reference numeral. The side surface 33d is the left surface in Fig. 6 and may hereinafter be referred to as the left surface 33d using the same reference numeral.

[0095] The side surface 33e is the rear surface in Fig. 6 and may be referred to as the rear surface 33e using the same reference numeral hereinafter. The side surface 33f is the right surface in Fig. 6 and may be referred to as the right surface 33f using the same reference numeral hereinafter.

[0096] An internal space 34 is defined within the bottom surface 33a, the top surface 33b, and the four side surfaces 33c to 33f of the housing 32.

[0097] In this embodiment, the housing 32 is made of a member having heat insulating properties (heat insulating material), and the internal space 34 of the housing 32 is configured as a heat insulating space.

[0098] As shown in Fig. 6, in this embodiment, the internal space 34 of the housing 32 has a multi-layer structure made up of multiple levels 35 (35a, 35b). In this embodiment, a partition plate 36 is provided in the internal space 34 at a position approximately at the center in the height direction of the light source device 28A, so as to be approximately perpendicular to the height direction. The partition plate 36 divides the internal space 34 into a lower level 35a and an upper level 35b. It should be noted that the multi-layer structure may also be referred to as a hierarchical structure.

[0099] The lower story 35a corresponds to the lowest story among the multiple stories 35. The bottom surface 33a of the housing 32 forms the bottom surface of the lower story 35a, and the partition plate 36 forms the ceiling of the lower story 35a.

[0100] The upper story 35b corresponds to the highest story among the multiple stories 35. The partition plate 36 forms the bottom surface of the upper story 35b, and the top surface 33b forms the ceiling of the upper story 35b.

[0101] The housing 32 also has an inlet 37 through which air flows in and an outlet through which air flows out. In this embodiment, the inlet 37 is formed on the top surface 33b of the housing 32, i.e., on the ceiling of the upper level 35b. The outlet 38 is formed on the right surface 33f at a position that constitutes the lower level 35a. In other words, the inlet 37 is positioned higher than the outlet 38 in the height direction of the light source device 28A.

[0102] The partition plate 36 has through-holes (not shown), so that the lower level 35a and the upper level 35b are spatially continuous. As shown in Figure 6, air A1 is supplied to the internal space 34 through an inlet 37. The supplied air A1 passes through the upper level 35b and the lower level 35a and is exhausted to the outside of the light source device 28A through an outlet 38. The air exhausted through the outlet 38 is referred to as air A2.

[0103] The pulsed light source 15 is configured by accommodating the components of the pulsed light source 15 in a single housing. The pulsed light source 15 is accommodated in the internal space 34 of the housing part 32. Specifically, the pulsed light source 15 is disposed in the lower level 35a of the internal space 34.

[0104] During operation of the light source device 28A, the pulsed light source 15 serves as a heat source. In this embodiment, as shown in Figure 6, a laser exhaust port 39 is formed on the right side 33f at a position where the lower level 35a is configured. Heated air A3 discharged from the pulsed light source 15 is not discharged into the internal space 34 of the housing 32, but is discharged to the outside of the light source device 28A via the laser exhaust port 39.

[0105] That is, in the light source device 28A, the air A3 exhausted from the pulsed light source 15 is exhausted to the outside of the housing part 32 without passing through the lower level 35a and the upper level 35b.

[0106] The pulse stretcher 16 has its components (such as the divider 17, delay line 18, and coupler 19) mounted on a support member 40. The support member 40 may be, for example, an optical table.

[0107] 6, the pulse stretcher 16 is housed in the internal space 34 of the housing 32. Specifically, the pulse stretcher 16 is disposed in the upper level 35b of the internal space 34.

[0108] The pulse stretcher 16 is disposed below the inlet 37 for air A1 formed on the top surface 33b. Conversely, it can be said that the inlet 37 is formed above the pulse stretcher 16 disposed on the upper level 35b.

[0109] The FFU 31, which functions as the air blower 29, is provided on the top surface 33b of the housing 32. The FFU 31 has a built-in filter and fan, and removes dirt, dust, and the like contained in the air outside the light source device 28A, and supplies clean air A1 to the internal space 34 of the housing 32 via an inlet 37.

[0110] As described above, the light source device 28A according to this embodiment has an internal space 34 of the housing 32 having a multi-layer structure in which a plurality of stories 35 are stacked along the height direction of the light source device 28A. The pulse light source 15 and the pulse stretcher 16 are respectively arranged on different stories 35 among the plurality of stories 35.

[0111] Specifically, the pulse stretcher 16 is disposed on the upper story 35b, and the pulse light source 15 is disposed on the lower story 35a. That is, in the height direction of the light source device 28A, the pulse light source 15 is disposed on a story lower than the pulse stretcher 16.

[0112] An inlet 37 is formed on the top surface 33b at a position above the pulse stretcher 16. Then, the FFU 31 installed on the top surface 33b supplies clean air A1 through the inlet 37 to the upper level 35b on which the pulse stretcher 16 is arranged.

[0113] The clean air A1 flowing in through the inlet 37 is first supplied to the pulse stretcher 16 arranged on the upper level 35b, then passed through a through-hole (not shown) in the partition plate 36 and supplied to the pulse light source 15 arranged on the lower level 35a, and is then exhausted to the outside of the housing 32 through the outlet 38 (air A2).

[0114] That is, in the light source device 28A according to this embodiment, the pulse stretcher 16 is arranged upstream of the pulse light source 15 with respect to the flow path of the air A1 flowing in from the inlet 37.

[0115] In the light source device 28A according to this embodiment, the pulse light source 15 and the pulse stretcher 16 are housed in the same housing 32. The FFU 31 supplies clean air A1 to the internal space 34 of the housing 32.

[0116] This makes it possible to suppress temperature changes in the pulse stretcher 16, and to suppress fluctuations in the characteristics of the pulse stretcher 16. That is, it becomes possible to suppress fluctuations in the intensity, amplitude spectrum, phase spectrum, etc. of the wavelength swept light L1, and to achieve a stable output of the wavelength swept light L1.

[0117] It is also possible to suppress temperature changes in the pulsed light source 15, and to suppress fluctuations in the output intensity of the pulsed light source 15. As a result, it is possible to improve the measurement accuracy of the spectroscopic measurement device, and also improve the measurement stability.

[0118] When the inventors examined a prototype, they found that the stability of the output of the pulsed light source 15 was ±1% / ° C., and the stability of the output of the pulse stretcher 16 was ±2.5% / ° C. When the splitter 17 of the pulse stretcher 16 is configured with an AWG, the output decreases even if the focusing position of the light from the pulsed light source 15 is shifted by only μm from the incident position of the AWG.

[0119] As such, the pulse stretcher 16 is relatively more susceptible to temperature changes, and a configuration in which the pulse stretcher 16 is arranged on the upper level 35b close to the inlet 37 and the pulse light source 15 is arranged on the lower level 35a far from the inlet 37 is very effective.

[0120] That is, by arranging the pulse stretcher 16, which is relatively more susceptible to temperature changes out of the pulse light source 15 and the pulse stretcher 16, upstream of the flow path of the clean air A1 flowing in from the inlet 37, the temperature of the pulse stretcher 16 can be preferentially stabilized, thereby stabilizing the overall characteristics of the light source device 28A.

[0121] For example, when a commercially available unitized product is used as the pulse light source 15, the pulse stretcher 16 mounted on the support member 40 is often more susceptible to temperature fluctuations than the pulse light source 15. Therefore, by prioritizing stabilizing the temperature of the pulse stretcher 16, the performance of the entire light source device 28A can be improved.

[0122] As shown in Figure 6, in the light source device 28A, the air A3 exhausted from the pulse light source 15 is exhausted to the outside of the housing section 32 without passing through the lower level 35a on which the pulse light source 15 is arranged and the upper level 35b on which the pulse stretcher 16 is arranged.

[0123] The pulsed light source 15 can be considered a heat source, and the temperature of the air A3 exhausted from it is often higher than the temperature of the internal space 34 of the housing 32. Therefore, by exhausting the air A3 exhausted from the pulsed light source 15 directly to the outside, the temperature stability of the internal space 34 can be further improved.

[0124] 6, in the light source device 28A, the pulse light source 15, the pulse stretcher 16, and the FFU 31 can be arranged in the height direction of the light source device 28A, i.e., the vertical direction, which makes it possible to reduce the footprint of the light source device 28A (the space required to arrange the light source device 28A).

[0125] Of course, the fact that the pulse light source 15, the pulse stretcher 16, and the FFU 31 are integrally configured using the housing 32 is also advantageous in reducing the footprint of the light source device 28A.

[0126] In addition, a housing unit in which the components of the light source device 28A (pulse light source 15, pulse stretcher 16, FFU 31) can be arranged vertically, such as the housing unit 32 in this embodiment, can be called a tower-type housing unit.

[0127] In the housing unit 32 shown in Figure 6, the internal space 34 is divided into two levels: a lower level 35a and an upper level 35b. The space above the top surface 33b can also be considered a level, and the housing unit 32 can be considered a tower-type housing unit having three levels. In this case, the level 41 above the top surface 33b can be called the external top level or the roof level.

[0128] In this disclosure, the "plurality of stories" according to the present invention refers to the plurality of stories 35 configured in the interior space 34. That is, in the light source device 28A shown in Fig. 6, the lower story 35a and the upper story 35b are one embodiment of the "plurality of stories" according to the present invention.

[0129] The upper tier 35b is one embodiment of the "highest tier of the plurality of tiers" according to the present invention. The lower tier 35a is one embodiment of the "lowest tier of the plurality of tiers" and the "tier one level below the top tier." The top surface 33b is one embodiment of the "top surface" according to the present invention.

[0130] 6 , in the light source device 28A, an inlet 37 is formed in the top surface 33b and is disposed at a high position in the internal space 34 of the housing part 32. On the other hand, an outlet 38 is disposed at a low position in the internal space 34 of the housing part 32.

[0131] This makes it possible to generate an airflow (downflow) from top to bottom in the internal space 34 of the housing 32. As a result, it is possible to suppress particle accumulation on the support member 40 of the pulse stretcher 16 and on the unit. It is also possible to prevent particles from adhering to optical components in the laser optical path, thereby preventing deterioration of the optical components (including burning by the laser) and a resulting decrease in output power.

[0132] In this embodiment, the FFU 31 supplies air A1 downward in the height direction of the light source device 28A through the inlet 37, thereby fully exerting the effect of the downflow. Of course, the inlet 37 may be formed on the side surfaces 33c to 33f of the housing 32 as long as it is positioned higher than the outlet 38.

[0133] For example, the inlet 37 may be provided at a position 37a higher than the highest one of the components of the pulse light source 15 and the pulse stretcher 16. In this case, the FFU 31 may be attached at the position 37a. The downflow effect can be obtained even if the direction in which the air A1 is introduced by the FFU 31 is not downward but is horizontal or oblique.

[0134] (Configuration Example 2) Fig. 7 is a perspective view showing a light source device 28B illustrated as configuration example 2. In the light source device 28B shown in Fig. 7, the internal space 34 of the housing part 32 is not configured as a multi-layer structure. As shown in Fig. 7, the pulse light source 15 and the pulse stretcher 16 are arranged side by side on the bottom surface 33a of the housing part 32.

[0135] An inlet 37 and an FFU 31 are formed on the top surface 33b of the housing 32. The inlet 37 is formed at a position above the pulse stretcher 16. The FFU 31 supplies clean air A1 to the internal space 34 of the housing 32 via the inlet 37. The supplied clean air A1 is exhausted (air A2) to the outside of the light source device 28B from an outlet 38 formed at a position lower than the inlet 37.

[0136] This makes it possible to suppress temperature changes in the pulse stretcher 16, thereby realizing a stable output of the wavelength swept light L1. It also makes it possible to suppress temperature changes in the pulsed light source 15, thereby suppressing fluctuations in the output intensity of the pulsed light source 15. As a result, it becomes possible to improve the measurement accuracy of the spectroscopic measurement device.

[0137] In the light source device 28B shown in Fig. 7, the pulse light source 15 and the pulse stretcher 16 are arranged in parallel on the lowest surface 33a. Therefore, the foot space is larger than that of the light source device 28A shown in Fig. 6. On the other hand, it is possible to reduce the size in the height direction compared to the light source device 28A shown in Fig. 6.

[0138] 8 is a perspective view showing a light source device 28C illustrated as configuration example 3. The light source device C shown in FIG. 8 includes an air conditioner 43 in addition to a pulse light source 15, a pulse stretcher 16, and an FFU 31.

[0139] 8, the internal space 34 of the housing 32 according to this embodiment has a multi-layer structure consisting of three levels 44a to 44c. In this embodiment, two partition plates 36a and 36b are provided in the internal space 34 at positions that are approximately equally spaced apart in the height direction of the light source device 28C.

[0140] The space from the bottom surface 33a to the lower partition plate 36a is the lowest level 44a, which corresponds to the lowest level of the three levels 44a to 44c. The space from the lower partition plate 36a to the upper partition plate 36b is the middle level 44b, which corresponds to the middle level of the three levels 44a to 44c. The space from the upper partition plate 36b to the top surface 33b is the top level 44c, which corresponds to the highest level of the three levels 44a to 44c.

[0141] The upper partition plate 36b has a through-hole (not shown) formed therein, and the middle level 44b and the top level 44c are spatially continuous. These middle level 44b and the top level 44c form a space 45 to be air-conditioned (hereinafter referred to as the air-conditioned space).

[0142] 8, the pulse light source 15 is disposed on the middle level 44b. The pulse stretcher 16 is disposed on the top level 44c. An inlet 37 and an FFU 31 are formed on the top surface 33b of the housing 32. An outlet 38 is formed on the right surface 33f of the housing 32 at a position where the middle level 44b is formed.

[0143] The air conditioner 43 is disposed on the lowest floor 44a. That is, the air conditioner 43 is disposed on a floor lower than the pulse light source 15 and the pulse stretcher 16 in the height direction of the light source device 28C.

[0144] The air conditioner 43 generates temperature-adjusted controlled air A4 and includes a temperature sensor 46, a controller 47, a temperature adjustment device 48, and a fan 49.

[0145] The temperature sensor 46 is externally attached to the main body of the air conditioner 43. Specifically, the temperature sensor 46 is provided in the air-conditioned space 45 (the top floor 44c and the middle floor 44b) where the pulse stretcher 16 and the pulse light source 15 are installed.

[0146] The controller 47 performs feedback control on the temperature regulator 48 so that the value detected by the temperature sensor 46 approaches the target temperature. The fan 49 sends the controlled air A4, the temperature of which has been controlled by the temperature regulator 48, to the FFU 31 via an air duct 50 for heat insulation.

[0147] The FFU 31 has a built-in filter and fan, and removes dirt and dust from the controlled air A4, and sends the clean air A1 into the air-conditioned space 45.

[0148] In this embodiment, the air conditioner 43 is installed on a different floor from the pulse light source 15 and the pulse stretcher 16. More preferably, the air conditioner 43 is preferably arranged on a floor lower than the pulse light source 15 and the pulse stretcher 16.

[0149] This prevents damage to the pulse light source 15 and the pulse stretcher 16 in the unlikely event of a water leak from the air conditioner 43, which has a drain. In addition, the air conditioner 43 is heavy and vibrates during operation, so it is preferable to place it at a low position in the housing 32 from the viewpoint of rigidity.

[0150] 8, the air conditioner 43 is disposed on the lowest floor 44a, and the pulse light source 15 and the pulse stretcher 16 are installed in an air-conditioned space 45 including an intermediate floor 44b and a top floor 44c above the lowest floor 44a. The FFU 31 is installed on the floor 41 above the top surface 33b of the housing 32.

[0151] In this embodiment, the air-conditioned space 45 is insulated, and the size of the air-conditioned space 45 is preferably smaller than the entire area of ​​the middle floor 44b and the top floor 44c. By making the air-conditioned space 45 as small as possible, temperature stability can be improved. Note that the entire internal space 34 of the housing 32 may be configured as an insulated space, or only part of the internal space 34, the air-conditioned space 45, may be configured as an insulated space.

[0152] The inlet 37 for the clean air A1 in the air-conditioned space 45 is disposed at a position higher than the pulse light source 15 and the pulse stretcher 16. In this embodiment, the FFU 31 is disposed on the story 41 above the top surface 33b, and the inlet 37 is disposed on the top surface 33b of the air-conditioned space 45.

[0153] The inlet 37 for the clean air A1 may be located on the side of the air-conditioned space 45. In this case, the inlet 37 may be provided at a position 37a higher than the highest one of the components of the pulse light source 15 and the pulse stretcher 16. In this case, the FFU 31 may be attached at the position 37a.

[0154] The air-conditioned space 45 is provided with an outlet 38 at a position lower than the inlet 37. Air A2 exhausted from the outlet 38 passes through an air duct 51 for heat insulation and is returned to the FFU 31 as return air A5. The FFU 31 mixes the controlled air A4 from the air conditioner 43 with the return air A5 exhausted from the outlet 38, and supplies the mixed air to the air-conditioned space 45.

[0155] The air volume of the FFU 31 may be determined according to the size of the air-conditioned space 45 so that air reaches every corner of the air-conditioned space 45. On the other hand, the air volume of the air conditioner 43 may be smaller than the air volume of the FFU 31. That is, the air volume of the FFU 31 can be made larger than the air volume of the air conditioner 43. This is because the difference in air volume is made up by the air A2 (return air A5) discharged from the outlet 38.

[0156] The pulsed light source 15 is a heat source. The heated air A3 discharged from the pulsed light source 15 is not discharged into the air-conditioning space 45, but is discharged to the outside of the housing 32 through the laser exhaust port 39. In other words, the air A3 is not returned to the FFU 31.

[0157] The temperature sensor 46 is provided near the inlet 37 for the clean air A1. It can be said that the temperature of the air circulating through the light source device 28C is most stable near the inlet 37 (i.e., upstream of the air flow), and the closer it is to the outlet 38, the more it deviates from the target value.

[0158] In other words, when comparing the middle story 44b and the top story 44c, it can be said that the temperature of the top story 44c is more stable. Therefore, it is advisable to arrange one of the pulse light source 15 and the pulse stretcher 16, which is relatively susceptible to temperature changes, on the story (top story 44c) closer to the inlet 37, and to arrange the other, which is relatively less susceptible to temperature changes, on the story (middle story 44b) closer to the outlet 38.

[0159] As described above, when the inventors examined a prototype, they found that the stability of the output of the pulse light source 15 was ±1% / ° C., and the stability of the output of the pulse stretcher 16 was ±2.5% / ° C. When the splitter 17 of the pulse stretcher 16 is configured with an AWG, the output decreases even if the focusing position of the light from the light source is shifted by only μm from the incident position of the AWG.

[0160] Therefore, the pulse stretcher 16 is relatively more susceptible to temperature changes, and is arranged on the top floor 44c close to the inlet 37, while the pulse light source 15 is arranged on the middle floor 44b far from the inlet 37.

[0161] Focusing on the temperature sensor 46, it can be said that the temperature sensor 46 is disposed near one of the pulse light source 15 and the pulse stretcher 16, which is relatively more susceptible to temperature changes. In this embodiment, the temperature sensor 46 is disposed at a position closer to the pulse stretcher 16 than to the pulse light source 15.

[0162] In the light source device 28C according to this embodiment, the pulse light source 15 and the pulse stretcher 16 are housed in the same housing 32, and the temperature of the air-conditioned space 45 within the housing 32 is controlled and adjusted by an air conditioner 43.

[0163] This suppresses fluctuations in the output intensity of the pulse light source 15 and also suppresses fluctuations in the characteristics of the pulse stretcher 16. This suppresses fluctuations in the intensity, amplitude spectrum, phase spectrum, etc. of the wavelength swept light. Furthermore, by arranging the air conditioner 43, pulse light source 15, and pulse stretcher 16 vertically, the footprint of the light source device 28C can be reduced.

[0164] Furthermore, by arranging the pulse stretcher 16, which is relatively more susceptible to temperature changes than the pulse light source 15 or the pulse stretcher 16, closer to the inlet 37, the temperature of the pulse stretcher 16 can be stabilized preferentially, thereby stabilizing the overall characteristics of the light source device 28C.

[0165] For example, when a commercially available unitized product is used as the pulse light source 15, the pulse stretcher 16 mounted on the support member 40 is often more susceptible to temperature fluctuations than the pulse light source 15. Therefore, by locating the temperature sensor 46 in a position close to the pulse stretcher 16, the temperature of the pulse stretcher 16 can be preferentially stabilized, thereby improving the performance of the entire light source device 28C.

[0166] Furthermore, the control air temperature is closer to the target temperature the further upstream it is, and the further downstream it is, the more it deviates from the target temperature. Therefore, by arranging the pulse stretcher 16 upstream where the temperature is closer to the target value, the temperature of the pulse stretcher 16 can be preferentially stabilized.

[0167] Furthermore, by arranging the inlet 37 at a high position in the air-conditioned space 45 and the outlet 38 at a low position in the air-conditioned space 45, it is possible to generate an air flow (downflow) from top to bottom inside the housing part 32.

[0168] This makes it possible to suppress particle accumulation on the support member 40 and the unit of the pulse stretcher 16. It also makes it possible to prevent particles from adhering to optical components in the laser optical path, thereby preventing deterioration of the optical components (including burning by the laser) and a resulting decrease in output power.

[0169] The larger the air-conditioned space 45, the more difficult it becomes to regulate the temperature throughout the space, which may result in a loss of temperature uniformity within the space or the occurrence of areas with poor temperature stability. Therefore, it is necessary to supply air to the air-conditioned space 45 at a flow rate that corresponds to the size of the air-conditioned space 45.

[0170] If the air to be supplied to the air-conditioned space 45 were to be supplied solely by the air conditioner 43, a large air conditioner 43 would be required. According to the light source device 28C of this embodiment, it is possible to return the air A2 (return air A5) exhausted from the air-conditioned space 45 to the FFU 31, which is the blower 29, and mix it with the controlled air A4 before supplying it to the air-conditioned space 45. This makes it possible to control the temperature throughout the air-conditioned space 45 without increasing the size of the air conditioner 43, thereby improving the uniformity and stability of the temperature within the air-conditioned space 45.

[0171] The pulsed light source 15 can be considered a heat source, and the temperature of the air A3 exhausted from it is higher than the temperature in the air-conditioned space 45. Therefore, by exhausting the air A3 exhausted from the pulsed light source 15 directly to the outside, the temperature stability in the air-conditioned space 45 can be further improved.

[0172] Configuration Example 4 Fig. 9 is a perspective view showing a light source device 28D illustrated as configuration example 4. In the light source device 28D shown in Fig. 9, the internal space 34 of the housing 32 is configured as a multi-layer structure by a partition plate 36, and is divided into a lower level 53a and an upper level 53b.

[0173] 9, the lower story 53a is provided with an air conditioner 43. The upper story 53b is configured as an air-conditioned space, in which a pulse light source 15 and a pulse stretcher 16 are arranged in parallel.

[0174] An inlet 37 and the FFU 31 are formed on the top surface 33b of the housing part 32. The inlet 37 is formed at a position above the pulse stretcher 16.

[0175] Temperature-controlled controlled air A4 is sent from the air conditioner 43 to the FFU 31 via an air duct 50 for heat insulation. Air A2 exhausted from the outlet 38 is returned to the FFU 31 as return air A5 via an air duct 51 for heat insulation.

[0176] The FFU 31 mixes the controlled air A4 from the air conditioner 43 with the air A5 exhausted from the outlet 38 and supplies the mixed air to the upper level 53b.

[0177] As shown in Figure 9, on the upper level 53b, the pulse stretcher 16, which is relatively susceptible to temperature changes, is positioned near the inlet 37, and the pulse light source 15, which is less susceptible to temperature changes, is positioned near the outlet 38.

[0178] In the light source device 28D, it is also possible to suppress temperature changes in the pulse stretcher 16, thereby achieving stable output of the wavelength swept light L1. It is also possible to suppress temperature changes in the pulsed light source 15, thereby suppressing fluctuations in the output intensity of the pulsed light source 15. As a result, it is possible to improve the measurement accuracy of the spectroscopic measurement device.

[0179] In the light source device 28D shown in FIG. 9, the foot space is larger than that of the light source device 28C shown in FIG. 8, but the size in the height direction can be reduced.

[0180] Configuration Example 5 FIG. 10 is a perspective view showing a light source device 28E illustrated as configuration example 5. As shown in FIG.

[0181] In the light source device 28C shown in FIG. 8, air A3 exhausted from the air-conditioning space 45 is returned to the FFU 31, mixed with controlled air A4, and supplied to the air-conditioning space 45.

[0182] 10 does not include the air duct 51, and the air inside the air-conditioned space 45 is exhausted to the outside through the outlet 38. For example, if the volume of the air-conditioned space 45 is not particularly large, a configuration can be adopted in which only the controlled air A4 generated by the air conditioner 43 is supplied from the FFU 31 to the air-conditioned space 45.

[0183] In the light source device 28E, it is also possible to suppress temperature changes in the pulse stretcher 16, thereby realizing stable output of the wavelength swept light L1. It is also possible to suppress temperature changes in the pulsed light source 15, thereby suppressing fluctuations in the output intensity of the pulsed light source 15. As a result, it is possible to improve the measurement accuracy of the spectroscopic measurement device.

[0184] Configuration Example 6 FIG. 11 is a perspective view showing a light source device 28F illustrated as Configuration Example 6. As shown in FIG.

[0185] 6 and 7, the pulse light source 15 and the pulse stretcher 16 are housed in the internal space 34 of the housing 32. In the examples shown in Figures 8 to 10, the pulse light source 15, the pulse stretcher 16, and an air conditioner 43 are housed in the internal space 34 of the housing 32.

[0186] In contrast, in a light source device 28F shown in FIG. 11, only the pulse stretcher 16 is accommodated in the internal space 34 of the housing 32.

[0187] An inlet 37 and the FFU 31 are formed on the top surface 33b of the housing 32. The inlet 37 is formed at a position above the pulse stretcher 16. The FFU 31 supplies clean air A1 to the internal space 34 of the housing 32 via the inlet 37. The supplied clean air A1 is exhausted (air A2) to the outside of the light source device 28F from an outlet 38 formed at a position lower than the inlet 37.

[0188] 11, it is possible to suppress temperature changes in the pulse stretcher 16 and achieve stable output of the wavelength swept light L1, thereby improving the measurement accuracy of the spectroscopic measurement device.

[0189] Note that the air supplied to the pulse stretcher 16 by the FFU 31 may be, for example, air outside the light source device 28F (air in the environment where the light source device 28F is located). Alternatively, by preparing an air conditioner and connecting it to the FFU 31, it is also possible to provide temperature-adjusted controlled air to the pulse stretcher 16. This can improve the effect of suppressing temperature changes in the pulse stretcher 16.

[0190] As described above, in the light source devices 28A to 28F according to this embodiment, air is supplied to the pulse stretcher 16 by the FFU 31, which functions as the air blower 29. This makes it possible to suppress temperature changes in the pulse stretcher 16, and to stably output the wavelength swept light L1. Furthermore, the light source devices 28A to 28F can achieve the various effects described above.

[0191] <Other Embodiments> The present invention is not limited to the above-described embodiment, and various other embodiments can be realized.

[0192] In the above, examples have been given of a configuration in which the pulse stretcher 16 is arranged at a position higher than the pulse light source 15 in the height direction of the light source devices 28A to 28F, and a configuration in which the pulse stretcher 16 is arranged at the same height and in parallel with the pulse light source 15. Also, examples have been given of a configuration in which the pulse stretcher 16 is arranged upstream of the pulse light source 15 with respect to the flow path of the air A1 flowing in from the inlet 37.

[0193] Without being limited to this configuration, as long as the air A1 supplied by the blower 29 (FFU 31) reaches the pulse stretcher 16, a configuration in which the pulse light source 15 is positioned at a higher position than the pulse stretcher 16 or a configuration in which the pulse light source 15 is positioned upstream of the pulse stretcher 16 with respect to the flow path of the air A1 flowing in from the inlet 37 may be adopted.

[0194] For example, in the example shown in Fig. 6, the pulse stretcher 16 may be arranged on the lower story 35a, and the pulse light source 15 may be arranged on the upper story 53b. Also, in the examples shown in Figs. 8 and 10, the pulse stretcher 16 may be arranged on the middle story 44b, and the pulse light source 15 may be arranged on the top story 44c. Then, air A1 may be supplied by the blower 29 (FFU 31) to the story on which the pulse light source 15 is arranged.

[0195] If air A1 reaches the pulse stretcher 16, it is possible to suppress temperature changes in the pulse stretcher 16 and achieve stable output of wavelength swept light L1, thereby improving the measurement accuracy of the spectroscopic measurement device.

[0196] Furthermore, depending on the respective configurations of the pulse light source 15 and the pulse stretcher 16, the pulse light source 15 may be more susceptible to temperature fluctuations than the pulse stretcher 16. In this case, it is effective to arrange the pulse light source 15 at a position (or on a nearby level) closer to the inlet 37 and the pulse stretcher 16 at a position (or on a nearby level) closer to the outlet 38.

[0197] The air conditioner 43 may be placed at a higher position than the pulse light source 15 and the pulse stretcher 16 .

[0198] 6, 8, and 10, the pulse light source 15 and the pulse stretcher 16 are each arranged on different stories among multiple stories in the tower-type casing 32. On the other hand, in the example shown in Fig. 9, the pulse light source 15 and the pulse stretcher 16 are each arranged on the same story in the tower-type casing 32. In this way, the arrangement of the pulse light source 15 and the pulse stretcher 16 on multiple stories is not limited, and any arrangement in which the pulse light source 15 and the pulse stretcher 16 are arranged on any of the multiple stories can be adopted.

[0199] In the above, a structure in which multiple layers are stacked along the height direction of the light source device has been given as an example of the multi-layer structure of the internal space 34 of the housing 32. The height direction of the light source device may be, for example, the vertical direction, but is not limited to this.

[0200] Furthermore, the direction in which the multiple layers are stacked is not limited to the height direction of the light source device. For example, a multi-layer structure in which multiple layers are stacked horizontally or diagonally may be adopted. For example, the internal space 34 of the housing 32 may be divided into multiple layers by one or more partition plates extending in a direction perpendicular to the mounting surface on which the light source device is mounted. A pulse light source, a pulse stretcher, an air conditioner, etc. may be arranged on each layer.

[0201] In the tower-type housing 32 illustrated in Figures 6 and 8 to 10, the lowest level may be referred to as the first level, and the levels one level above may be referred to as the second level, the third level, etc. In this case, the levels may be numbered including the level 41 above the top surface 33. For example, in the light source device 28C shown in Figure 8, the lowest level 44a may be referred to as the first level, the middle level 44b as the second level, the top level 44c as the third level, and the level 41 above the top surface 33 as the fourth level.

[0202] Although the embodiments of the present disclosure have been described using specific terms, this description is merely an example to facilitate understanding and does not limit the scope of the present disclosure or the claims. The scope of the present invention is defined by the claims, and therefore, embodiments, examples, and modifications not described herein are also included in the scope of the present invention.

[0203] The above-described embodiments are merely examples and do not limit the disclosure, and all features and combinations thereof described in the embodiments are not necessarily essential to the disclosure. Furthermore, the dimensions (thickness, length, width, etc.) of each member shown in the drawings may be enlarged or reduced as appropriate for ease of understanding. Furthermore, the dimensions of multiple members do not necessarily represent their relative sizes. Even if a member A is depicted as being thicker than another member B in the drawings, member A may actually be thinner than member B.

[0204] The configurations of the spectroscopic measurement device, light source device, pulsed light source, pulse stretcher, air conditioner, and feed unit (FFU), the sample measurement method, and the wavelength sweep light generation method described with reference to the drawings are merely exemplary embodiments and may be modified as desired without departing from the spirit of the present invention. In other words, any other configurations, processing flows, algorithms, etc. may be adopted for implementing the present invention.

[0205] In this disclosure, terms such as "approximately" and "substantially" are used as appropriate to facilitate understanding of the explanation. However, there is no clear difference between using and not using terms such as "approximately." In other words, in this disclosure, concepts that define shape, size, positional relationship, state, etc., such as "center," "middle," "equal," "same," "orthogonal," and "parallel," include concepts such as "substantially center," "substantially central," "substantially equal," "substantially the same," "substantially orthogonal," and "substantially parallel."

[0206] In the present disclosure, expressions using "than", such as "greater than A" and "smaller than A", are expressions that comprehensively include both concepts that include the case where something is equivalent to A and concepts that do not include the case where something is equivalent to A. For example, "greater than A" is not limited to cases that do not include the case where something is equivalent to A, but also includes "A or more". Furthermore, "smaller than A" is not limited to "less than A" but also includes "A or less". When implementing the present invention, specific settings and the like can be appropriately adopted from the concepts included in "greater than A" and "smaller than A" so that the effects described above can be achieved.

[0207] It is also possible to combine at least two of the features of the present technology described above. That is, the various features described in each embodiment may be arbitrarily combined without distinguishing between the embodiments. Furthermore, the various effects described above are merely examples and are not intended to be limiting, and other effects may also be achieved.

[0208] A1...Clean air flowing into inlet A2...Air flowing out from outlet A3...Air exhausted from pulsed light source A4...Controlled air A5...Return air L1...Wavelength swept light L1a...Broadband pulsed light L2...Object light L3...Reference light 1, 10...Spectroscopic measurement device 2, 11, 28 (28A to 28F)...Light source device 15...Pulse light source 16...Pulse stretcher 17...Splitter 18...Delay line 19...Coupler 29...Blower device 31...FFU 32...Housing part 33a...Bottom surface 33b...Top surface 33c to 33f...Side surfaces 33a...Bottom surface 35...Level 35a, 53a...Lower level 35b, 53b...Upper level 37...Inlet 38...Outlet 43...Air conditioner 44a...Lower level 44b...Middle layer 44c...Top layer 44b...Middle layer

Claims

1. A light source device that generates wavelength swept light, comprising: a pulse light source that generates pulse light having a continuous spectrum; a pulse stretcher configured to stretch the pulse light on a time axis to generate the wavelength swept light; and a blower that supplies air to the pulse stretcher.

2. A light source device as claimed in claim 1, further comprising: a housing section having an inlet through which the air flows and an outlet through which the air flows out, and accommodating the pulse stretcher in an internal space; and the blower device supplies the air to the internal space via the inlet.

3. A light source device according to claim 2, wherein the housing accommodates the pulsed light source in the internal space.

4. A light source device according to claim 3, wherein the pulse stretcher is disposed upstream of the pulse light source with respect to the flow path of the air flowing in from the inlet.

5. A light source device as described in claim 3, wherein the internal space of the housing has a multi-layer structure consisting of a plurality of levels, the pulse light source and the pulse stretcher are each arranged on one of the plurality of levels, and the blower supplies the air to the level on which the pulse stretcher is arranged.

6. A light source device according to claim 5, wherein the pulse light source and the pulse stretcher are each disposed in a different layer among the plurality of layers.

7. A light source device as described in claim 6, wherein, among the plurality of floors, a floor on which the pulse light source is arranged and a floor on which the pulse stretcher is arranged are spatially continuous, and the air blowing device supplies the air to the floor on which the pulse stretcher is arranged or the floor on which the pulse light source is arranged.

8. A light source device according to claim 5, wherein the multi-layer structure is a structure in which the plurality of layers are stacked along the height direction of the light source device.

9. A light source device according to claim 2, wherein the inlet is positioned higher than the outlet in the height direction of the light source device.

10. A light source device as described in claim 2, wherein the housing portion has a top surface that constitutes the ceiling of the top floor that is located at the highest position among the plurality of floors, the inlet is formed on the top surface, and the blower device supplies the air downward in the height direction through the inlet.

11. A light source device according to claim 10, wherein the air blowing device is arranged on the uppermost surface.

12. A light source device according to claim 10, wherein the pulse stretcher is arranged in the topmost layer, the pulse light source is arranged in a layer one level below the topmost layer, and the topmost layer and the layer one level below the topmost layer are spatially continuous.

13. A light source device according to claim 2, further comprising an air conditioner that generates temperature-adjusted controlled air, said air blower supplying said controlled air to said pulse stretcher.

14. A light source device as claimed in claim 13, wherein the internal space of the housing has a multi-layer structure consisting of a plurality of levels, and the pulse light source, the pulse stretcher and the air conditioner are each disposed on a different level among the plurality of levels.

15. A light source device as described in claim 14, wherein the multi-layer structure is a structure in which the multiple layers are stacked along the height direction of the light source device, and the air conditioner is arranged on a layer lower than the pulse light source and the pulse stretcher in the height direction of the light source device.

16. A light source device according to claim 13, wherein the air conditioner has a temperature sensor provided in the vicinity of the inlet.

17. A light source device according to claim 16, wherein the temperature sensor is disposed at a position closer to the pulse stretcher than the pulse light source.

18. A light source device according to claim 2, wherein the internal space of the housing is configured as a heat-insulating space.

19. A light source device according to claim 13, wherein the air blowing device supplies a mixture of the air discharged from the outlet and the control air to the pulse stretcher.

20. A light source device according to claim 19, wherein the air volume of the blower is greater than the air volume of the air conditioner.

21. A light source device according to claim 5, wherein air exhausted from said pulse light source is exhausted to the outside of said housing section without passing through a floor on which said pulse stretcher is arranged.

22. A light source device according to claim 1, wherein the air blowing device is a fan filter unit.

23. A light source device according to claim 1, wherein the pulse stretcher comprises: an arrayed waveguide diffraction grating that spatially divides the pulse light emitted from the pulse light source into a plurality of beams according to wavelength; and a plurality of fibers having different optical path lengths corresponding to the plurality of beams.

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