Ablation unit and analyzer

Abstract

An ablation unit according to one aspect of the present disclosure is a unit for performing ablation by irradiating a surface of a target object with laser light, comprising: a laser device for emitting the laser light; a light reflection device for reflecting the laser light to an arbitrary position; a fθ lens and an objective lens for condensing the laser light transmitted through the same on the surface of the target object; and a switching means for switching the fθ lens and / or the objective lens so as to transmit the laser light.

Description

Ablation unit and analyzer

[0001] The present disclosure relates to an ablation unit and an analyzer.

[0002] There is known an analyzer that irradiates a target object with a laser beam and analyzes the elements contained in the target object. One such analyzer includes an ablation unit that includes a laser beam emitted from a laser light source and an optical system that reflects the laser beam toward the target object, and an analyzer that performs analysis using an inductively coupled plasma method (WO 2019 / 202689).

[0003] International Publication No. 2019 / 202689

[0004] The analyzer described in Patent Document 1 is said to be able to widen the area that can be analyzed on the object because the ablation unit can reflect the laser light with two mirrors and move the irradiation position two-dimensionally. On the other hand, there is also a demand for detailed analysis of a small area on the object.

[0005] In view of the above circumstances, an object of the present disclosure is to provide an ablation unit that can perform efficient ablation of a relatively wide area on the surface of a target object, and precise ablation of a relatively narrow area.

[0006] An ablation unit according to one aspect of the present disclosure, which has been made to solve the above-mentioned problems, is a unit that performs ablation by irradiating the surface of an object with laser light, and includes a laser device that emits laser light, a light reflecting device that reflects the laser light to any position, an fθ lens and an objective lens that focus the transmitted laser light on the surface of the object, and a switching means that switches either or both of the fθ lens and the objective lens so that the laser light is transmitted through them.

[0007] An ablation unit according to one aspect of the present disclosure can perform efficient ablation of a relatively wide area on the surface of a target object, as well as precise ablation of a relatively narrow area.

[0008] Fig. 1 is a schematic side view showing a state in which laser light of an ablation unit of an analyzer according to an embodiment of the present disclosure passes through an objective lens. Fig. 2 is a schematic side view showing a state in which laser light of the ablation unit of Fig. 1 passes through an fθ lens. Fig. 3 is a schematic side view showing a state in which laser light of the ablation unit of Fig. 1 passes through an fθ lens in a manner different from that of Fig. 2. Fig. 4 is a schematic side view showing a state in which laser light of an ablation unit according to an embodiment different from that of Fig. 1 passes through an objective lens. Fig. 5 is a schematic side view showing a state in which laser light of the ablation unit of Fig. 4 passes through an fθ lens.

[0009] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described.

[0010] (1) An ablation unit according to one aspect of the present disclosure is a unit that performs ablation by irradiating the surface of an object with laser light, and includes a laser device that emits laser light, a light reflecting device that reflects the laser light to any position, an fθ lens and an objective lens that focus the transmitted laser light on the surface of the object, and a switching means that switches either or both of the fθ lens and the objective lens so that the laser light is transmitted through them.

[0011] The ablation unit includes two types of lenses, an fθ lens and an objective lens, and a switching means for transmitting laser light through either or both of the fθ lens and the objective lens. The ablation unit can perform efficient ablation on a relatively wide area of ​​the surface of the object by transmitting the laser light through the fθ lens, and can perform precise ablation on a relatively narrow area of ​​the surface of the object by transmitting the laser light through the objective lens.

[0012] (2) In the above (1), the ablation unit may have a plurality of the objective lenses. By having a plurality of objective lenses, it is possible to increase the focused diameter of the laser light, which can be selectively changed.

[0013] (3) In the above (1) or (2), the diameter of the laser light focused by the objective lens may be 2 μm or less. This allows for more precise ablation.

[0014] (4) In any of (1) to (3) above, the ablation unit may further include an image processing device including a camera that captures an image of the object and a monitor that displays the image from the camera, and the camera may be positioned on the axis of the laser light incident on the object. By including the image processing device in the ablation unit, it is possible to observe the state of the object being ablated. By positioning the camera of the image processing device on the axis of the laser light incident on the object, it is possible to improve the accuracy of observation of the object.

[0015] (5) In any of (1) to (4) above, the ablation unit may further include a cell in which the object is housed and a stage on which the cell is disposed, and the stage may be movable in the axial direction of the laser light incident on the object and in two directions perpendicular to the axial direction and perpendicular to each other. By including a cell in which the object is housed and a stage on which the cell is disposed and movable in three axes, the position and depth at which the laser light is focused on the object can be easily adjusted.

[0016] (6) In the above (5), the cell may be fixed to the stage by magnetic force, which makes it possible to easily place the cell on the stage.

[0017] (7) In any one of (1) to (6), the laser device may have a femtosecond pulse laser oscillator and may be capable of setting a repetition rate of 1 kHz or more. By setting a repetition rate of 1 kHz or more and irradiating the target object with the laser light, efficient ablation can be achieved.

[0018] (8) In the above (7), the pulse interval of the laser device may be set to 600 femtoseconds or less. By irradiating the target object with the laser light at a pulse interval of 600 femtoseconds or less, the aerosol generated by ablation can be made finer.

[0019] (9) In the above (7) or (8), the wavelength of the laser light may be deep ultraviolet. By using a deep ultraviolet wavelength of the laser light, the aerosol produced by ablation can be made finer.

[0020] (10) In any one of (7) to (9), the optical reflector may be a galvanometer mirror device that changes the reflection angle in response to the repetition frequency. By using a galvanometer mirror device that can change the reflection angle in response to the repetition frequency, more efficient ablation can be achieved.

[0021] (11) An analyzer according to one aspect of the present disclosure includes an ablation unit according to any one of (1) to (10) above and an analysis unit that performs elemental analysis.

[0022] The analyzer includes the ablation unit, and therefore can perform efficient and highly accurate analysis of the elements of the object.

[0023] [Details of the embodiment of the present disclosure] Hereinafter, the embodiment of the present disclosure will be described in detail with reference to the drawings. Note that the drawings are illustrative of the embodiment, and the shape, size, scale, arrangement, etc. of each component (member) may differ from the actual ones.

[0024] First Embodiment As shown in FIGS. 1, 2, and 3, the analyzer 10 includes the ablation unit 100 and an analysis unit 200 that performs elemental analysis, and analyzes the chemical composition of a target object (not shown).

[0025] [Analysis Unit] The analysis unit 200 is not particularly limited, and may be, for example, a device that performs a known analysis method such as inductively coupled plasma mass spectrometry or high frequency inductively coupled plasma atomic emission spectrometry.

[0026] [Ablation Unit] The ablation unit 100 irradiates the surface of the object contained in the cell 170 with laser light L (shown by a dashed line in each figure) to ablate it, thereby partially aerosolizing the object. Specifically, the laser light L vaporizes the surface of the object, partially ionizing it. The laser light L then penetrates the object to a depth of several nanometers to several micrometers from the surface and releases most of its energy, vaporizing and fragmenting the object's constituent components. This ablation releases the ionized and vaporized elements, some of which recondense into solid particles, and fragmented fragments as aerosols from the object. The aerosol is transported to the analysis unit 200 via the gas exhaust pipe P2 by a carrier gas, such as helium, supplied into the cell 170, where the chemical composition of the object is analyzed.

[0027] The ablation unit 100 includes a laser device 110 that emits laser light L, a light reflecting device that reflects the laser light L at any position, an fθ lens 130 and an objective lens that focus the transmitted laser light L on the surface of the object, and a switching means that switches either or both of the fθ lens 130 and the objective lens so that the laser light L passes through.

[0028] The ablation unit 100 preferably has a plurality of the above-described objective lenses. The ablation unit 100 of this embodiment has three objective lenses 141, 142, and 143. Specifically, the ablation unit 100 has a first objective lens 141, a second objective lens 142, and a third objective lens 143, each of which has a different lens magnification (hereinafter, these three objective lenses 141, 142, and 143 may also be simply referred to as "objective lenses 140"). This increases the options for different focused diameters of the laser light L.

[0029] (Laser Device) The laser device 110 emits laser light L to irradiate the surface of the target object (hereinafter also referred to as the "target surface"). The laser device 110 includes a known laser oscillator (not shown), such as a solid-state laser, a semiconductor laser, or a gas laser. It is preferable that the wavelength range of the laser light L can be set arbitrarily. It is preferable that the laser light L is irradiated in a wavelength range in the deep ultraviolet region. That is, it is preferable that the laser device 110 can set the wavelength range of the laser light L to the deep ultraviolet region. Specifically, it is preferable that the wavelength of the laser light L can be set to 280 nm or less, more preferably 270 nm or less, and even more preferably 260 nm or less. The lower limit of the wavelength that can be set is not particularly limited and may be, for example, 100 nm. Irradiating the target surface with laser light L of such a wavelength can promote the aerosol micronization by ablation.

[0030] The laser light L emitted from the laser device 110 may be a continuous wave, but is preferably a pulse wave. The pulse width of the pulse wave of the laser light L emitted from the laser device 110 can preferably be set arbitrarily. The pulse width is preferably settable to 600 femtoseconds or less, and more preferably settable to 300 femtoseconds or less. By irradiating the target object with laser light L having such a pulse width, it is possible to further promote the aerosolization by ablation.

[0031] By setting the wavelength and pulse width of the laser light L within the above ranges, the absorption efficiency of the energy of the laser light L (laser energy) on the target surface is improved, and the depth to which the laser light L penetrates into the surface (superficial layer) of the target object is reduced. In other words, the laser energy can be absorbed in a small volume.

[0032] When analyzing a solid sample (e.g., analyzing the elements contained therein), irradiating the solid sample with laser light L in the deep ultraviolet wavelength range and a short pulse of 600 femtoseconds or less improves the absorption efficiency of laser energy on the surface of the solid sample, thereby reducing the depth of the ablation scar. Specifically, the depth of the ablation scar can be controlled in nanometer units. By reducing the depth of the ablation scar, accurate analysis of the solid sample in the depth direction can be performed. In other words, a precise depth profile of the solid sample can be obtained. Note that the ablation scar (also called a spot, crater, etc.) refers to a groove (hole) formed in the solid sample by ablation with laser light.

[0033] Furthermore, efficient absorption of laser energy by the surface of the solid sample promotes the fragmentation of fragments generated on the surface, improving aerosolization and ultimately improving the analytical accuracy of the analyzer 200. Specifically, the average particle size of the fragments generated on the surface can be set to 400 nm or less, or 300 nm or less, or 200 nm or less. This promotes ionization of the fragments by plasma in the analyzer 200, improving the analytical accuracy. The average particle size refers to the particle size at 50% of the integrated value in the particle size distribution determined by the laser diffraction / scattering method.

[0034] It is preferable that the repetition frequency of the pulse wave of the laser light L can be set arbitrarily. The repetition frequency can be set preferably to 1 kHz or more, more preferably to 10 kHz or more, and even more preferably to 100 kHz or more. By irradiating the target object with laser light L having such a repetition frequency, it is possible to increase the ablation speed.

[0035] (Light Reflecting Device) The light reflecting device reflects the laser light L so that the laser light L irradiates a desired position on the target surface. That is, the light reflecting device controls the irradiation position of the laser light L on the target surface. Although not particularly limited, the light reflecting device is preferably a galvanometer mirror device. The ablation unit 100 of this embodiment has a first galvanometer mirror device 121 that controls the irradiation position of the laser light L passing through the objective lens 140, and a second galvanometer mirror device 122 that controls the irradiation position of the laser light L passing through the fθ lens 130. By using such galvanometer mirror devices 121 and 122, the laser light L passing through the fθ lens 130 and the objective lens 140 can be moved to a desired position on the target surface, making it easy to ablate a desired position or area on the target surface.

[0036] The first galvanometer mirror device 121 has a first reflecting mirror 121a and a second reflecting mirror 121b. The first galvanometer mirror device 121 includes a driver (not shown) that rotates and drives each of the two reflecting mirrors 121a and 121b to change the reflection angle, and a controller (not shown) that controls the driver. The first reflecting mirror 121a reflects the laser light L to move the irradiation position in one direction (X direction). The second reflecting mirror 121b reflects the laser light L reflected by the first reflecting mirror 121a to move the irradiation position in a direction (Y direction) perpendicular to the one direction.

[0037] Similar to the first galvanometer mirror device 121, the second galvanometer mirror device 122 has a third reflecting mirror 122a that moves the irradiation position of the laser light L that passes through the fθ lens 130 in the X direction, and a fourth reflecting mirror 122b that moves the irradiation position of the laser light L reflected by the third reflecting mirror 122a in the Y direction.

[0038] The galvanometer mirror devices 121 and 122 are preferably capable of changing the reflection angle in response to the repetition frequency of the laser light L. That is, the first reflecting mirror 121 a and the second reflecting mirror 121 b and the third reflecting mirror 122 a and the fourth reflecting mirror 122 b are preferably capable of changing the reflection angle in synchronization with the repetition frequency of the laser light L. This allows for efficient ablation. For example, this can increase the speed of ablation that scans the target surface, or it can increase the speed and efficiency of ablation of multiple regions of the target object or multiple targets contained in the cell 170 simultaneously and at any time rate.

[0039] The ablation unit 100 of this embodiment has an objective lens reflecting mirror 151 that reflects the laser light L reflected by the first galvanometer mirror device 121, and an fθ lens reflecting mirror 152 that reflects the laser light L reflected by the second galvanometer mirror device 122. The objective lens reflecting mirror 151 reflects the laser light L toward the objective lens 140. The fθ lens reflecting mirror 152 reflects the laser light L toward the fθ lens 130.

[0040] The objective lens reflecting mirror 151 is preferably a dichroic mirror. The dichroic mirror reflects the laser light L reflected by the first galvanometer mirror device 121 toward the objective lens 140 and transmits other light. By using a dichroic mirror as the objective lens reflecting mirror 151, it is possible to easily position the first camera 191 so as to face the cell 170, as will be described later.

[0041] [Switching means] The ablation unit 100 of this embodiment has a first laser reflecting mirror 161 that reflects the laser light L toward the first galvanometer mirror device 121, a second laser reflecting mirror 162 that reflects the laser light L toward the second galvanometer mirror device 122, and a third laser reflecting mirror 163 that reflects the laser light L emitted from the laser device 110 toward the second laser reflecting mirror 162.

[0042] The second laser reflecting mirror 162 is disposed on the optical axis of the laser light L reflected by the third laser reflecting mirror 163. The first laser reflecting mirror 161 is configured to move between on the optical axis of the laser light L reflected by the third laser reflecting mirror 163 and outside the optical axis. That is, the first laser reflecting mirror 161 moves between a position where it reflects the laser light L reflected by the third laser reflecting mirror 163 and a position where it does not reflect the laser light L. When the first laser reflecting mirror 161 moves to a position where it reflects the laser light L reflected by the third laser reflecting mirror 163 toward the first galvanometer mirror device, the laser light L passes through the objective lens 140. When the first laser reflecting mirror 161 moves to a position where it does not reflect the laser light L reflected by the third laser reflecting mirror 163, the laser light L is reflected by the second laser reflecting mirror 162 and passes through the fθ lens 130. That is, the first laser reflecting mirror 161 is configured as a means for switching the optical path of the laser light L. The ablation unit 101 can selectively ablate the object using laser light L that has passed through the fθ lens 130 and ablate the object using laser light L that has passed through the objective lens 140 by switching the optical path through the movement of the first laser reflector 161.

[0043] The means by which the first laser reflecting mirror 161 moves between a position where it reflects the laser light L reflected by the third laser reflecting mirror 163 and a position where it does not reflect the laser light L is not particularly limited. For example, as shown in FIG. 2, the first laser reflecting mirror 161 may be configured to move in the X direction, or as shown in FIG. 3, the first laser reflecting mirror 161 may be rotated so that the third laser reflecting mirror 163 moves away from the optical axis of the reflected laser light L.

[0044] [Lens] The fθ lens 130 and the objective lens 140 adjust the focused diameter of the laser light L. In the laser ablation unit 100 of this embodiment, the fθ lens 130 and the objective lens 140 are arranged in parallel in the X direction. The fθ lens 130 focuses the laser light L on the surface of the object with a relatively large focused diameter, while the objective lens 140 focuses the laser light L with a smaller focused diameter than the fθ lens 130. A beam expander lens (not shown) that expands the beam diameter may be arranged upstream of the fθ lens 130 and the objective lens 140.

[0045] The three objective lenses 141, 142, and 143 are held in parallel in the X direction by a lens holder 144. The lens holder 144 is mounted on an objective lens moving means (not shown), such as a known one-axis stage, and can move in the X direction. By moving the lens holder 144, the ablation unit 100 can arbitrarily select one of the three objective lenses 141, 142, and 143 to vary the focused diameter of the laser light L on the target surface.

[0046] The focused diameter of the laser light L by the objective lens 140 is preferably 2 μm or less. That is, it is preferable that any one of the three objective lenses 141, 142, and 143 has a magnification that can make the focused diameter of the laser light L on the target surface 2 μm or less. The focused diameter at the above magnification is more preferably 1.5 μm or less, even more preferably 1.0 μm or less, and particularly preferably 0.5 μm or less. By irradiating the target surface with the laser light L at such a focused diameter, precise ablation can be performed.

[0047] Specifically, it is preferable to select the lens magnification so that the focused light diameter is 0.5 μm for the first objective lens 141, 3.0 μm for the second objective lens 142, and 5.0 μm for the third objective lens 143. The lens magnifications of the three objective lenses 141, 142, and 143 may be, for example, 60x, 40x, and 20x, or may be 50x, 20x, and 10x. The focused light diameter of the fθ lens 130 may be, for example, 10 μm.

[0048] [Cell] The object to be ablated is accommodated in cell 170. Cell 170 is a container that accommodates the object to be ablated and prevents the aerosol generated by ablation from scattering. A transparent plate (not shown) through which laser light L is incident is disposed on the top surface of cell 170. That is, cell 170 has a light incident portion formed of a transparent plate on the incident surface of laser light L.

[0049] The cell 170 has a gas supply port 171 through which a carrier gas that transports the aerosol to the analysis unit 200 is supplied, and a gas exhaust port 172 through which the carrier gas containing the aerosol is exhausted. A gas supply pipe P1 is connected to the gas supply port 171, and a gas exhaust pipe P2 is connected to the gas exhaust port 172.

[0050] [Stage] The cell 170 is placed on the stage 180. Specifically, the cell 170 containing the object to be measured is placed on the mounting surface (top surface) of the stage 180 so as not to move relative to the stage 180.

[0051] The means for preventing the cell 170 from moving relative to the stage 180 is not particularly limited, and may be fixed with bolts, pins, or the like, but is preferably fixed by magnetic force. Specifically, it is preferable that a magnet (not shown) is placed on the stage 180, and the cell 170, which is made of a magnetic material such as metal, is fixed by the magnetic force of the magnet. A coil (not shown) that generates a magnetic force when energized may also be placed on the stage 180. The magnet or the coil may be placed on the cell 170, or may be placed on both the stage 180 and the cell 170. It is preferable that a guide portion (not shown) is provided on the mounting surface of the stage 180 to determine the position at which the cell 170 is placed.

[0052] The stage 180 is preferably capable of moving the cell 170 in the axial direction (Z direction) of the laser light L incident on the object, and in two directions (X direction and Y direction) that are perpendicular to this axial direction and perpendicular to each other. In other words, it is preferable that the mounting surface of the stage 180 is movable in the X-Y-Z directions. This makes it possible to easily adjust the irradiation position of the laser light L on the object in the X-, Y-, and Z-directions.

[0053] The Z-direction movement means (adjustment means) on the mounting surface of the stage 180 is not particularly limited, but is preferably configured to be adjustable by piezoelectric element drive. The upper limit of the minimum movement distance (resolution) in the Z-direction movement is preferably 5 nm, more preferably 2 nm, and even more preferably 1 nm. The lower limit of the minimum movement distance is not particularly limited and may be, for example, 0.1 nm. By setting the minimum movement distance within the above range, the focusing position of the laser light L in the Z direction can be efficiently determined. In other words, the focus of the fθ lens 130 and the objective lens 140, the depth to which the laser light L penetrates the object (depth of the ablation scar), and the like can be adjusted with high precision, resulting in efficient aerosolization and improved analysis accuracy by the analysis unit 200. The stage 180 may be a goniostage capable of changing the angle in the X-Y plane.

[0054] The stage 180 can move between a first position where the object is ablated by the objective lens 140 and a second position where the object is ablated by the fθ lens 130. That is, the ablation unit 100 has a stage moving means (not shown) that moves the stage 180 between the first position and the second position. The stage moving means is not particularly limited, and for example, the stage 180 may be disposed on a known one-axis stage.

[0055] The switching means and the stage moving means are configured to operate in synchronization with each other. That is, when the first laser reflecting mirror 161 moves to a position where it reflects the laser light L toward the first galvanometer mirror device, the stage 180 is moved to the first position (on the optical axis of the laser light L reflected by the objective lens reflecting mirror 151) by the stage moving means. When the first laser reflecting mirror 161 moves to a position where it does not reflect the laser light L toward the first galvanometer mirror device, the stage 180 is moved to the second position (on the optical axis of the laser light L reflected by the fθ lens reflecting mirror 152) by the stage moving means.

[0056] [Image Processing Device] The ablation unit 100 preferably includes an image processing device including a camera that captures an image of the object to be ablated and a monitor that displays the image from the camera. The ablation unit 100 of this embodiment has an image processing device that includes a first camera 191 that captures an image of the object to be ablated by the objective lens 140, a second camera 192 that captures an image of the object to be ablated by the fθ lens 130, and a monitor (not shown) that displays the images captured by these cameras 191 and 192. The monitor is not particularly limited, and may be, for example, a liquid crystal display.

[0057] The first camera 191 is preferably disposed opposite the cell 170 across the objective lens 140 in the axial direction of the laser light L incident on the object. The first camera 191 in this embodiment is disposed above the objective lens reflecting mirror 151 (the side opposite to where the laser light L is reflected) and on an extension of the optical axis of the laser light L passing through the objective lens 140. This arrangement improves the accuracy of observing the object being ablated by the laser light L passing through the objective lens 140.

[0058] The second camera 192 may be disposed at an angle with respect to the optical axis of the laser light L passing through the fθ lens 130. In other words, the second camera 192 may be disposed so as to capture an image of the object housed in the cell 170 from diagonally above.

[0059] Second Embodiment An ablation unit 101 according to another embodiment of the present invention will now be described with reference to Figures 4 and 5. Note that the same components as those in the ablation unit 100 described above will be denoted by the same reference numerals, and description thereof will be omitted.

[0060] The ablation unit 101 includes a laser device 110 that emits laser light L, a light reflecting device that reflects the laser light L at any position, an fθ lens 131 and an objective lens 145 that focus the transmitting laser light L on the surface of the object, and a switching means that switches either or both of the fθ lens 131 and the objective lens 145 so that the laser light L passes through.

[0061] The ablation unit 101 has one galvanometer mirror device 123 as an optical reflecting device. That is, the laser light L of the ablation unit 101 has one optical path. Therefore, the ablation unit 101 does not have a first laser reflecting mirror 161 that switches the optical path, or the stage moving means that moves the stage 180 in the X direction. The laser light L reflected by the galvanometer mirror device 123 is reflected by the lens reflecting mirror 153 and introduced into the fθ lens 131 and the objective lens 145.

[0062] In the laser ablation unit 101 of this embodiment, the fθ lens 131 and the objective lens 145 are arranged vertically in the Z direction. The objective lens 145 includes three objective lenses 141, 142, and 143 held by a lens holder 144.

[0063] [Switching Means] The ablation unit 101 has a lens moving means (not shown) that moves the fθ lens 131 and the objective lens 145 in the X direction. The lens moving means includes a first lens mover (not shown) that moves the fθ lens 131 and a second lens mover (not shown) that moves the objective lens 145. The first lens mover moves the fθ lens 131 to a position where the laser light L reflected by the galvanometer mirror device 123 passes through and a position where it does not pass through. The second lens mover moves the objective lens 145 to a position where the laser light L reflected by the galvanometer mirror device 123 passes through and a position where it does not pass through. The lens moving means is not particularly limited and may be, for example, a known one-axis stage on which the fθ lens 131 and the objective lens 145 can be positioned, respectively.

[0064] When the lens moving means moves the fθ lens 131 to a position through which the laser light L passes, it moves the objective lens 145 to a position through which the laser light L does not pass. Furthermore, when the lens moving means moves the fθ lens 131 to a position through which the laser light L does not pass, it moves the objective lens 145 to a position through which the laser light L passes. In other words, the lens moving means is configured as a switching means that switches the positions of the fθ lens 131 and the objective lens 145. By switching the positions of the fθ lens 131 and the objective lens 145 using the lens moving means, the ablation unit 101 can selectively perform ablation of the object with the laser light L that has passed through the fθ lens 131 and ablation of the object with the laser light L that has passed through the objective lens 145.

[0065] <Ablation Method> The ablation method using the ablation units 100 and 101 mainly includes the steps of placing a cell 170 containing an object to be ablated on a stage 180, displaying the object to be ablated on the stage 180 and imaged by cameras 191 and 192 on a monitor, selecting whether the laser light L passes through the fθ lenses 130 and 131 or the objective lenses 140 and 145, determining a position or area on the object to be irradiated with the laser light L, irradiating the determined position or area with the laser light L, and transporting the aerosol generated by ablation to the analysis unit 200. The object to be ablated is not particularly limited and may be a solid or a liquid. In this ablation method, the object to be ablated will be described as a solid.

[0066] [Placing Step] In the placing step, the cell 170 containing the object to be measured is placed on the stage 180. The cell 170 is preferably fixed so as not to move relative to the stage 180. A gas supply pipe P1 and a gas exhaust pipe P2 are connected to the cell 170 placed on the stage 180, and preparations are made for the supply and exhaust of a carrier gas.

[0067] In the displaying step, the object placed on stage 180 and imaged by cameras 191 and 192 is displayed on a monitor. On the monitor on which the object is displayed, the operator can observe the state of the object before and after being irradiated with laser light L, and the state of the object being ablated.

[0068] [Selecting Step] In the selecting step, the transmission of the laser light L through either the fθ lenses 130, 131 or the objective lenses 140, 145 is selected. The transmission of the laser light L through the fθ lenses 130, 131 or the objective lenses 140, 145 is switched by the switching means. When ablation of a relatively wide area, multiple areas of the object, or multiple objects is performed, efficient ablation can be achieved by selecting the fθ lenses 130, 131. When ablation of a relatively narrow area, analysis of the object in the depth direction, or high-precision analysis is performed, it is preferable to select the objective lenses 140, 145.

[0069] [Determining Step] In the determining step, a position or area on the object to be irradiated with the laser light L is determined. That is, a position or area on the object to be analyzed is determined. The position or area may be determined on a monitor displaying the object. Specifically, for example, a known touch panel may be used as the monitor, and the position on the object displayed on the touch panel to be irradiated with the laser light L may be designated and determined using a touch pen or the like, or a continuous position (linear area) or a closed area (planar area) may be determined by tracing the displayed object with a touch pen or the like, and the laser light L may be irradiated onto the determined position or area. The control unit of the galvanometer mirror devices 121, 122, and 123 may be configured to receive the position or area determined on the touch panel, convert it into coordinate information, and control the drive unit based on the coordinate information.

[0070] [Irradiation Step] In the irradiation step, the determined position or region is irradiated with laser light L. The irradiation step preferably includes a first irradiation means for irradiating the outer periphery of the edge of the determined position or region with laser light L, and a second irradiation means for irradiating the position or region with laser light L after the first irradiation means. That is, before irradiating the position or region with laser light L to start analysis, it is preferable to irradiate the outer periphery of the edge with laser light L to partially remove a certain width and depth. In this way, ablation of a region not to be analyzed (non-analysis region) can be suppressed when irradiating the edge of the position or region (analysis region) with laser light L. That is, aerosolization of the non-analysis region can be suppressed simultaneously with aerosolization of the analysis region. This improves the purity of the aerosol generated in the analysis region and the analytical accuracy of the analysis region.

[0071] It is preferable to irradiate the laser light L so that the depth of the ablation mark formed by the second irradiating means is shallower than the depth of the ablation mark formed by the first irradiating means, thereby making it possible to further suppress ablation of the non-analysis region at the same time as ablation of the analysis region.

[0072] The conditions of the laser light L in the irradiation step, such as the output, wavelength, focused diameter, and pulse width, may be set appropriately depending on the physical properties of the object, the analysis method, the purpose of the analysis, etc. By setting the laser light L to a focused diameter of 2 μm or less, a wavelength region in the deep ultraviolet, a pulse width of 600 femtoseconds or less, and a repetition frequency of 1 kHz or more, the analytical accuracy by the analysis unit 200 can be improved.

[0073] In the transporting step, the aerosol generated by the ablation in the irradiating step is transported to the analyzing unit 200. Specifically, the carrier gas supplied into the cell 170 is discharged together with the aerosol, and is transported to the analyzing unit 200 through the gas exhaust pipe P2. The analyzing unit 200 analyzes the object by a known analytical method such as inductively coupled plasma mass spectrometry or high frequency inductively coupled plasma atomic emission spectrometry.

[0074] <Advantages> The ablation units 100, 101 can use the switching means to switch between transmitting the laser light L through the fθ lenses 130, 131 and transmitting the laser light L through the objective lenses 140, 145. The ablation units 100, 101 can perform efficient ablation of the target object by transmitting the laser light L through the fθ lenses 130, 131, and can perform precise ablation of the target object by transmitting the laser light L through the objective lenses 140, 145.

[0075] [Other Embodiments] The above-described embodiments do not limit the configuration of the present invention. Therefore, the above-described embodiments may include omissions, substitutions, or additions of components based on the description in this specification and common general technical knowledge, and all of these should be construed as falling within the scope of the present invention.

[0076] The ablation unit is not limited to being used in an analyzer, but may also be used in, for example, a laser processing machine that processes an object with laser light.

[0077] The ablation unit in the first embodiment described above may include another fθ lens (second fθ lens) upstream of the objective lens, i.e., the laser light may be configured to pass through the second fθ lens and then pass through the objective lens to ablate the target object.

[0078] Although the ablation unit in the second embodiment has been described as being configured such that the laser light passes through an fθ lens or an objective lens, the laser light may pass through both the fθ lens and the objective lens. That is, the ablation unit may be capable of selecting ablation by laser light that has passed through an fθ lens, ablation by laser light that has passed through the objective lens, or ablation by laser light that has passed through an fθ lens and the objective lens.

[0079] The ablation unit may have one objective lens.

[0080] The ablation unit may also include other optical lenses such as an imaging lens, other optical mirrors such as a half mirror, and an illumination device for illuminating the object, as long as the ablation of the object is not hindered.

[0081] An ablation unit according to one aspect of the present disclosure can be used in an analyzer that uses a laser to analyze elements contained in a target object, thereby enabling efficient and highly accurate analysis.

[0082] 10 analyzer 100, 101 ablation unit 110 laser device 121, 122, 123 galvanometer mirror device 121a first reflecting mirror 121b second reflecting mirror 122a third reflecting mirror 122b fourth reflecting mirror 130, 131 fθ lens 140, 145 objective lens 141 first objective lens 142 second objective lens 143 third objective lens 144 lens holder 151 reflecting mirror for objective lens 152 reflecting mirror for fθ lens 153 reflecting mirror for lens 161 first laser reflecting mirror 162 second laser reflecting mirror 163 third laser reflecting mirror 170 cell 171 gas supply port 172 gas exhaust port 180 stage 191 first camera 192 second camera 200 analysis unit L Laser light P1 Gas supply pipe P2 Gas exhaust pipe

Claims

1. An ablation unit that irradiates the surface of an object with laser light to perform ablation, comprising: a laser device that emits laser light; a light reflecting device that reflects the laser light to any position; an fθ lens and an objective lens that focus the transmitted laser light on the surface of the object; and a switching means that switches either or both of the fθ lens and the objective lens so that the laser light passes through.

2. The ablation unit according to claim 1, comprising a plurality of said objective lenses.

3. An ablation unit according to claim 1 or 2, wherein the diameter of the laser light focused by the objective lens is 2 μm or less.

4. An ablation unit as described in claim 1 or claim 2, further comprising an image processing device including a camera for capturing an image of the object and a monitor for displaying the image captured by the camera, wherein the camera is positioned on the axis of the laser light incident on the object.

5. An ablation unit as described in claim 1 or claim 2, further comprising: a cell in which an object to be subjected to irradiation is housed; and a stage on which said cell is placed, said stage being capable of moving said cell in the axial direction of the laser light incident on the object to be subjected to irradiation and in two directions perpendicular to this axial direction and perpendicular to each other.

6. The ablation unit according to claim 5, wherein said cell is fixed to said stage by magnetic force.

7. The ablation unit according to claim 1, wherein said laser device has a femtosecond pulse laser oscillator and the repetition frequency can be set to 1 kHz or higher.

8. The ablation unit according to claim 7, wherein the pulse interval of the laser light can be set to 600 femtoseconds or less.

9. An ablation unit according to claim 7 or 8, wherein the wavelength of said laser light is in the deep ultraviolet range.

10. An ablation unit as set forth in claim 7 or claim 8, wherein the optical reflection device is a galvanometer mirror device, which changes the reflection angle in response to the repetition frequency.

11. An analyzer comprising: an ablation unit according to claim 1 or 2; and an analysis unit for performing elemental analysis.

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