Beam scanning device, processing device, and processing method

Abstract

This beam scanning device comprises: a first focusing optical system that focuses a processing beam entering the beam scanning device; a beam branching member that allows the processing beam from the first focusing optical system to pass therethrough; a second focusing optical system that focuses the processing beam that has passed through the beam branching member; and a scanning optical member that performs scanning using the processing beam that has traveled through the beam branching member. The beam branching member comprises an optical member provided with an opening and a light-reflecting part at different positions, and uses the light-reflecting part to reflect light that enters via the scanning optical member. The first focusing optical system forms a focal point at or near the position of the opening.

Description

Beam scanning device, processing device, and processing method

[0001] The present invention relates to the technical field of, for example, a beam scanning device that scans a processing beam, and a processing device and processing method that can process an object using the processing beam from the beam scanning device.

[0002] An example of a beam scanning device that scans a processing beam is described in Patent Document 1. Such a beam scanning device is required to appropriately scan the processing beam.

[0003] U.S. Patent No. 7,531,772

[0004] According to a first aspect, there is provided a beam scanning device for scanning a processing beam used in a processing apparatus, comprising: a first focusing optical system for focusing the processing beam incident on the beam scanning device; a beam splitting member through which the processing beam from the first focusing optical system passes; a second focusing optical system for focusing the processing beam that has passed through the beam splitting member; and a scanning optical member for scanning the processing beam that has passed through the beam splitting member, wherein the beam splitting member comprises an optical member in which an opening and a light reflecting member are provided at different positions, and the light incident through the scanning optical member is reflected by the light reflecting member, and the first focusing optical system forms a focusing point at or near the position of the opening.

[0005] According to a second aspect, there is provided a processing apparatus including the beam scanning apparatus provided by the first aspect, which processes an object using a processing beam from the beam scanning apparatus.

[0006] According to a third aspect, there is provided a processing method including emitting a processing beam from the beam scanning device provided by the first aspect, and scanning the processing beam on the object.

[0007] FIG. 1 is a cross-sectional view showing the configuration of a processing system according to this embodiment. FIG. 2 is a cross-sectional view showing the configuration of a beam scanning device according to this embodiment. FIG. 3(a) is a perspective view showing a beam splitter having a first example of an opening, and FIG. 3(b) is a cross-sectional view showing the beam splitter having the first example of an opening. FIG. 4(a) is a perspective view showing a beam splitter having a second example of an opening, and FIG. 4(b) is a cross-sectional view showing the beam splitter having the second example of an opening. FIG. 5 is a cross-sectional view showing the configuration of a beam scanning device according to this embodiment. FIG. 6(a) is a perspective view showing a beam splitter onto which observation light is incident, and FIG. 6(b) is a cross-sectional view showing the beam splitter onto which the observation light is incident. FIG. 7(a) is a perspective view showing a beam splitter onto which the observation light is incident, and FIG. 7(b) is a cross-sectional view showing the beam splitter onto which the observation light is incident. FIG. 8 shows an observation image generated by the light receiving device according to this embodiment. FIG. 9 is a cross-sectional view showing the configuration of a processing device according to a modified example. FIG. 10(a) is a perspective view showing a modified example of the beam splitter, and FIG. 10(b) is a cross-sectional view showing the modified example of the beam splitter.

[0008] Hereinafter, embodiments of a beam scanning device, a processing device, and a processing method will be described with reference to the drawings. Hereinafter, the embodiments of the beam scanning device, the processing device, and the processing method will be described using a processing system 1 to which the embodiments of the beam scanning device, the processing device, and the processing method are applied. In particular, the following description will be given of an example in which the processing system 1 is a processing system (i.e., an additive processing system) capable of forming a three-dimensional structure (three-dimensional workpiece) by performing additive processing.

[0009] In the following description, the positional relationships of the various components constituting the machining system 1 will be described using an XYZ Cartesian coordinate system defined by mutually orthogonal X, Y, and Z axes. For ease of explanation, the X-axis and Y-axis directions are each assumed to be horizontal (i.e., a predetermined direction within a horizontal plane), and the Z-axis direction is assumed to be vertical (i.e., a direction perpendicular to the horizontal plane, essentially an up-down direction). Furthermore, the rotation directions around the X-axis, Y-axis, and Z-axis (in other words, tilt directions) are referred to as the θX direction, θY direction, and θZ direction, respectively. Here, the Z-axis direction may be the direction of gravity. Furthermore, the XY plane may be assumed to be horizontal.

[0010] (1) Configuration of Processing System 1 First, the configuration of the processing system 1 will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view showing the configuration of the processing system 1.

[0011] As shown in FIG. 1, the processing system 1 includes a processing device 2 and a control device 3. For ease of explanation, FIG. 1 does not show a cross section of the control device 3. The processing device 2 is a device that can form a three-dimensional structure by performing additive processing. The processing device 2 may also be referred to as an additive processing device. The control device 3 controls the processing device 2 so that the processing device forms a three-dimensional structure by performing additive processing. In other words, the processing device 2 forms a three-dimensional structure under the control of the control device 3. The processing system 1 that includes the processing device 2 and the control device 3 may also be referred to as a processing device.

[0012] In order to form a three-dimensional structure, the processing device 2 includes a material supply tank 4, a recoater 5, a forming tank 6, and a beam scanning device 7.

[0013] The material supply tank 4 is a container for containing a modeling material M for forming a three-dimensional structure. A bottom surface 41 of the material supply tank 4 is moved in the vertical direction (Z-axis direction) by a drive mechanism (not shown) under the control of the control device 3. The modeling material M is, for example, a powder. As an example, the modeling material M may be at least one of a metal powder and a resin powder. However, the modeling material M does not have to be a powder.

[0014] The recoater 5, under the control of the control device 3, supplies the modeling material M contained in the material supply tank 4 to the modeling tank 6. In particular, the recoater 5 flattens the surface of the modeling material M supplied to the modeling tank 6 to form a material layer ML, which is a layer of the modeling material M. The bottom surface of the modeling tank 6 is an elevation stage 61. The elevation stage 61, under the control of the control device 3, moves in the vertical direction (Z-axis direction) by a drive mechanism (not shown).

[0015] The beam scanning device 7 irradiates at least a portion of the material layer ML formed in the building tank 6 with the processing light EL. Specifically, the beam scanning device 7 irradiates a processing surface MLs, which is at least a portion of the surface of the material layer ML formed in the building tank 6, with the processing light EL. Note that the processing light EL may also be referred to as a processing beam. When the processing light EL is irradiated onto at least a portion of the material layer ML, at least a portion of the material layer ML melts. That is, a molten pool MP is formed in the material layer ML. In other words, a molten pool MP is formed on the processing surface MLs. After that, when the processing light EL is no longer irradiated onto the molten material layer ML (i.e., the molten pool MP), the molten material layer ML solidifies. As a result, a structure layer SL corresponding to the solidified material layer ML is formed. The structure layer SL may be equivalent to a sintered layer formed by sintering the building material M. The structure layer SL may be equivalent to a solidified layer formed by solidifying the molten building material M.

[0016] The beam scanning device 7, under the control of the control device 3, selectively irradiates the material layer ML with the processing light EL to selectively solidify the material layer ML. To selectively irradiate the material layer ML with the processing light EL, the beam scanning device 7 deflects the processing light EL using a scanning optical element 74 (described later). That is, the beam scanning device 7 changes the emission direction of the processing light EL from the beam scanning device 7 using the scanning optical element 74 (described later). For example, the beam scanning device 7 deflects the processing light EL along a direction parallel to the lifting stage 61 (i.e., a direction parallel to the material layer ML, which in the example shown in FIG. 1 is a direction parallel to the XY plane). As a result, the irradiation position of the processing light EL on the surface of the material layer ML moves along a direction parallel to the lifting stage 61 (i.e., a direction parallel to the material layer ML and the processing surface MLs, which in the example shown in FIG. 1 is a direction parallel to the XY plane). In this way, the beam scanning device 7 can scan the processing light EL. In other words, the beam scanning device 7 is capable of scanning with the processing light EL. In further other words, the beam scanning device 7 is capable of scanning using the processing light EL. For example, the beam scanning device 7 is capable of scanning at least a portion of the material layer ML with the processing light EL. For example, the beam scanning device 7 is capable of scanning the processing surface MLs with the processing light EL.

[0017] After the structure layer SL is formed, the lift stage 61 descends. After the lift stage 61 descends (in the example shown in FIG. 1 , the lift stage 61 moves toward the −Z side), the recoater 5 forms a new material layer ML on the lift stage 61 (more specifically, on the already-formed structure layer SL and the already-formed old material layer ML). Then, the beam scanning device 7 irradiates the newly formed material layer ML with the processing light EL. That is, the beam scanning device 7 irradiates the processing surface MLs, which is at least a part of the surface of the newly formed material layer ML, with the processing light EL. In other words, the beam scanning device 7 irradiates the uppermost material layer ML with the processing light EL. That is, the beam scanning device 7 irradiates the processing surface MLs, which is at least a part of the surface of the uppermost material layer ML, with the processing light EL. As a result, a new structure layer SL is formed on the already-formed structure layer SL. That is, the new structure layer SL is stacked on the already-formed structure layer SL.

[0018] Thereafter, the processing apparatus 2 repeats the same operations under the control of the control device 3. That is, the processing apparatus 2 alternately repeats an operation of forming a material layer ML mainly using the recoater 5, an operation of solidifying at least a portion of the material layer ML to form a structure layer SL mainly using the beam scanning device 7, and an operation of lowering the lifting stage 61. As a result, a three-dimensional structure in which a plurality of structure layers SL are stacked is formed on the lifting stage 61. That is, the processing apparatus 2 performs additional processing on the lifting stage 61 (specifically, performs additional processing using the material layer ML formed on the lifting stage 61), thereby forming a three-dimensional structure on the lifting stage 61. In other words, the processing apparatus 2 performs additional processing on the lifting stage 61 using the material layer ML formed on the lifting stage 61, thereby forming a three-dimensional structure on the lifting stage 61. In this way, the processing device 2 performs additive processing based on powder bed fusion, such as selective laser sintering (SLS), to form a three-dimensional structure.

[0019] The control device 3 is capable of controlling the operation of the processing device 2. For example, the control device 3 may be capable of controlling the movement of the lifting stage 61. That is, the control device 3 may be capable of controlling the lifting stage 61. For example, the control device 3 may be capable of controlling the formation of the material layer ML by the recoater 5. That is, the control device 3 may be capable of controlling the recoater 5. For example, the control device 3 may be capable of controlling the irradiation of the processing light EL by the beam scanning device 7. That is, the control device 3 may be capable of controlling the beam scanning device 7.

[0020] The control device 3 may include, for example, an arithmetic device 31 and a storage device 32. The arithmetic device 31 may include, for example, at least one of a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit). The storage device 32 may include, for example, a memory. The control device 3 functions as a device that controls the operation of the machining device 2 by the arithmetic device 31 executing a computer program. This computer program is a computer program for causing the arithmetic device 31 to perform (i.e., execute) the operations to be performed by the control device 3, which will be described later. In other words, this computer program is a computer program for causing the control device 3 to function so as to cause the machining device 2 to perform the operations to be performed by the control device 3. The computer program executed by the arithmetic device 31 may be recorded in the storage device 32 (i.e., a recording medium) included in the control device 3, or may be recorded in any storage medium (e.g., a hard disk or a semiconductor memory) built into or externally attachable to the control device 3. Alternatively, the arithmetic device 31 may download the computer program to be executed from a device external to the control device 3 via a network interface. The storage device 32 may also be referred to as a recording device.

[0021] The control device 3 may be provided as a server or the like outside the machining system 1. In this case, the control device 3 and the machining system 1 may be connected via a wired and / or wireless network (or a data bus and / or a communication line). The wired network may be a network using a serial bus interface, such as at least one of IEEE 1394, RS-232x, RS-422, RS-423, RS-485, and USB. The wired network may be a network using a parallel bus interface. The wired network may be a network using an Ethernet (registered trademark) interface, such as at least one of 10BASE-T, 100BASE-TX, and 1000BASE-T. The wireless network may be a network using radio waves. An example of a radio wave network is a network compliant with IEEE 802.1x (for example, at least one of a wireless LAN and Bluetooth (registered trademark)). A network using infrared rays may be used as the wireless network. A network using optical communication may be used as the wireless network. In this case, the control device 3 and the processing system 1 may be configured to be able to send and receive various information via the network. Furthermore, the control device 3 may be able to send information such as commands and control parameters to the processing system 1 via the network. The processing system 1 may include a receiving device that receives information such as commands and control parameters from the control device 3 via the network. The processing system 1 may include a transmitting device that transmits information such as commands and control parameters to the control device 3 via the network (i.e., an output device that outputs information to the control device 3). Note that an apparatus including the processing system 1 and the control device 3 may be referred to as a processing system.

[0022] Alternatively, the control device 3 may be provided inside the processing system 1. That is, the processing system 1 may include the control device 3. Alternatively, a first control device that performs part of the processing performed by the control device 3 may be provided inside the processing system 1, while a second control device that performs another part of the processing performed by the control device 3 may be provided outside the processing system 1.

[0023] A computational model that can be constructed by machine learning may be implemented in the control device 3 by the arithmetic device 31 executing a computer program. An example of a computational model that can be constructed by machine learning is a computational model including a neural network (so-called artificial intelligence (AI)). In this case, learning of the computational model may include learning of parameters of the neural network (e.g., at least one of a weight and a bias). The control device 3 may control the operation of the processing device 2 using the computational model. That is, the operation of controlling the operation of the processing device 2 may include the operation of controlling the operation of the processing device 2 using the computational model. Note that a computational model that has been constructed by offline machine learning using teacher data may be implemented in the control device 3. Furthermore, the computational model implemented in the control device 3 may be updated by online machine learning on the control device 3. Alternatively, the control device 3 may control the operation of the processing device 2 using a computational model implemented in a device external to the control device 3 (i.e., a device provided outside the processing system 1) in addition to or instead of the computational model implemented in the control device 3.

[0024] The recording medium for recording the computer program executed by the control device 3 may be at least one of the following: a CD-ROM, CD-R, CD-RW, a flexible disk, an MO, a DVD-ROM, a DVD-RAM, a DVD-R, a DVD+R, a DVD-RW, a DVD+RW, and an optical disk such as Blu-ray (registered trademark), a magnetic medium such as a magnetic tape, a magneto-optical disk, a semiconductor memory such as a USB memory, and any other medium capable of storing a program. The recording medium may also include a device capable of recording a computer program (for example, a general-purpose device or a dedicated device in which a computer program is implemented in a state in which it can be executed in at least one of the forms of software and firmware). Furthermore, each process or function included in the computer program may be realized by a logical processing block realized within the control device 3 when the control device 3 (i.e., the computer) executes the computer program, or may be realized by a predetermined gate array (for example, hardware such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit)) provided in the control device 3, or may be realized in a form that mixes logical processing blocks and partial hardware modules that realize some elements of the hardware.

[0025] (2) Configuration of Beam Scanning Device 7 Next, the configuration of the beam scanning device 7 will be described with reference to Fig. 2. Fig. 2 is a cross-sectional view showing the configuration of the beam scanning device 7. Note that the configuration of the beam scanning device 7 shown in Fig. 2 is an example, and the configuration of the beam scanning device 7 is not limited to the configuration shown in Fig. 2.

[0026] As shown in FIG. 2, the beam scanning device 7 includes a condensing optical system 71, a beam splitter 72, a condensing optical system 73, a scanning optical member 74, an observation optical system 75, and a light receiving device .

[0027] The processing light EL emitted by the beam scanning device 7 toward the material layer ML is supplied to the beam scanning device 7 from a light source 8 included in the processing system 1 (or a light source 8 external to the processing system 1). The light source 8 generates the processing light EL. In this embodiment, an example will be described in which the light source 8 generates infrared light as the processing light EL. That is, the light source 8 generates processing light EL having a peak wavelength of 1000 nm or a wavelength around 1000 nm. In other words, the light source 8 generates processing light EL in a wavelength band having a peak wavelength of 1000 nm or a wavelength around 1000 nm. However, the light source 8 may generate light other than infrared light as the processing light EL. For example, the light source 8 may generate at least one of visible light and ultraviolet light as the processing light EL.

[0028] In the present embodiment, a light source capable of changing the cross-sectional intensity profile of the emitted processing light EL may be used as the light source 8. Examples of light sources capable of changing the cross-sectional intensity profile of the emitted processing light EL are described in, for example, U.S. Patent No. 10,423,015 and International Patent Publication No. 2023 / 056435.

[0029] The processed light EL generated by the light source 8 is supplied from the light source 8 to the beam scanning device 7. In the following description, an example will be described in which the processed light EL is supplied from the light source 8 to the beam scanning device 7 via an optical fiber 81, as shown in Fig. 8 . However, the processed light EL may be supplied from the light source 8 to the beam scanning device 7 using a method other than the method using the optical fiber 81. For example, the processed light EL may be supplied from the light source 8 to the beam scanning device 7 via a mirror.

[0030] The processing light EL propagating from the light source 8 through the optical fiber 81 enters the beam scanning device 7. Specifically, the processing light EL propagating from the light source 8 through the optical fiber 81 enters the focusing optical system 71 of the beam scanning device 7. In particular, in this embodiment, the processing light EL is incident on the focusing optical system 71 in a diverging state. That is, the processing light EL, which is diverging light, enters the focusing optical system 71. In this case, the focusing optical system 71 focuses the processing light EL that is incident on the beam scanning device 7 in a diverging state. That is, the focusing optical system 71 focuses the processing light EL, which is diverging light.

[0031] However, the focusing optical system 71 may focus the processing light EL that is incident on the beam scanning device 7 in a convergent state (converging state). That is, the focusing optical system 71 may focus the processing light EL that is convergent light (converging light). Note that when the processing light EL is incident on the beam scanning device 7 in a convergent state, the beam scanning device 7 does not need to be equipped with the focusing optical system 71. Alternatively, the focusing optical system 71 may focus the processing light EL that is incident on the beam scanning device 7 as parallel light. That is, the focusing optical system 71 may focus the processing light EL that is parallel light.

[0032] The processing light EL that has passed through the focusing optical system 71 is incident on the beam splitter 72. That is, the processing light EL from the focusing optical system 71 is incident on the beam splitter 72.

[0033] The beam splitting member 72 is a plate-shaped member. In particular, in this embodiment, the beam splitting member 72 includes an opening 721. The opening 721 is a part of the beam splitting member 72 that can function as an opening through which the processing light EL can pass (in other words, a light passing portion).

[0034] A first example of the opening 721 is shown in FIG. 3( a), a perspective view showing a beam splitting member 72 including the first example of the opening 721, and FIG. 3( b), a cross-sectional view showing the beam splitting member 72 including the first example of the opening 721. As shown in FIGS. 3( a) and 3(b), the opening 721 may be an opening 7211 that penetrates from one surface of the beam splitting member 72 (e.g., the surface on the +Y side in FIGS. 2 and 3) to the other surface of the beam splitting member 72 (e.g., the surface on the -Y side in FIGS. 2 and 3). In other words, the opening 721 may include a portion of the beam splitting member 72 where the opening 7211 is formed. In this case, the beam splitting member 72 may have an opening 7211 formed therein that functions as the opening 721. A second example of the opening 721 is shown in FIG. 4( a), a perspective view showing a beam splitting member 72 including the second example of the opening 721, and FIG. 4(b), a cross-sectional view showing the beam splitting member 72 including the second example of the opening 721. As shown in FIGS. 4A and 4B , the opening 721 may be a non-reflective portion 7212 of the beam splitting member 72 that includes a non-reflective surface 723 that does not function as a reflective surface 722 (described in detail below). Specifically, a reflective film 7221 capable of reflecting the observation light OL is formed on at least a portion of the surface of the beam splitting member 72 (particularly, the surface onto which the observation light OL described below is incident; in the example shown in FIGS. 4A and 4B , the surface on the −Y side). The reflective film 7221 may be a reflective film made of aluminum, or a reflective film on which a thin dielectric film is laminated. In this case, the surface portion of the surface of the beam splitting member 72 on which the reflective film 7221 is formed functions as the reflective surface 722. On the other hand, the surface portion of the surface of the beam splitting member 72 on which the reflective film 7221 is not formed functions as a non-reflective surface 723. Therefore, the non-reflective portion 7212 capable of functioning as the opening 721 may be a continuous portion of the beam splitting member 72 extending from one surface of the beam splitting member 72 (for example, the surface on the +Y side in FIGS. 2 and 3) to the other surface of the beam splitting member 72 (for example, the surface on the −Y side in FIGS. 2 and 3) along the traveling direction of the processing light EL, and may be a portion of the beam splitting member 72 that includes the non-reflective surface 723. The non-reflective portion 7212 may be transparent to the processing light EL.In other words, the non-reflective portion 7212 may be a member that allows the processing light EL to pass through.

[0035] 3(a) and 3(b), a reflective film 7221 capable of reflecting the observation light OL is formed on at least a portion of the surface of the beam splitting member 72 (particularly, the surface onto which the observation light OL described later is incident; in the example shown in FIGS. 3(a) and 3(b), the surface on the -Y side) as shown in FIGS. 3(a) and 3(b). In other words, the surface portion of the surface of the beam splitting member 72 on which the reflective film 7221 is formed functions as the reflective surface 722. For this reason, the first example of the opening 721 shown in FIGS. 3(a) and 3(b) may be considered to differ from the second example of the opening 721 shown in FIGS. 4(a) and 4(b), in which a physical opening 7211 (i.e., a through-hole) is formed in the opening 721, in that a physical opening 7211 (i.e., a through-hole) is formed in the opening 721.

[0036] An anti-reflection film may be formed on the surface of the reflective film 7221. In this case, an anti-reflection film may also be formed on the opening 721. For example, if the processing light EL can pass through the anti-reflection film, an anti-reflection film may also be formed on the opening 721. Alternatively, an anti-reflection film may not be formed on the opening 721. In other words, an opening corresponding to the opening 721 may be formed in the anti-reflection film.

[0037] 2, 3(a) to 3(b), and 4(a) and 4(b) show examples in which an opening 721 having a circular shape in a plan view is formed in the beam splitting member 72. That is, FIGS. 2, 3(a) to 3(b), and 4(a) and 4(b) show examples in which an opening 721 having a circular shape along the surface of the beam splitting member 72 is formed in the beam splitting member 72. However, the shape of the opening 721 may be a shape other than a circle. For example, the shape of the opening 721 may be an ellipse. For example, the shape of the opening 721 may be a polygon.

[0038] The processing light EL incident on the beam splitting member 72 passes through the opening 721. That is, the processing light EL incident on the beam splitting member 72 passes through the beam splitting member 72 via the opening 721. In other words, the beam splitting member 72 passes the processing light EL incident on the beam splitting member 72. That is, the beam splitting member 72 passes the processing light EL incident on the beam splitting member 72 through the opening 721.

[0039] To realize a state in which the processing light EL incident on the beam splitter 72 from the focusing optical system 71 passes through the opening 721, the focusing optical system 71 may focus the processing light EL at or near the opening 721. That is, the focusing optical system 71 may form a focusing point CP at which the processing light EL is focused at or near the opening 721. In other words, the focusing optical system 71 may form a focusing point CP of the processing light EL at or near the opening 721. Note that FIGS. 2, 3(a) to 3(b), and 4(a) to 4(b) show examples in which the focusing optical system 71 forms a focusing point CP of the processing light EL at the opening 721. In this way, when the focal point CP of the processing light EL is formed at or near the opening 721, a larger proportion of the light components of the processing light EL are irradiated onto the opening 721 of the beam splitter 72, compared to when the focal point CP of the processing light EL is not formed at or near the opening 721. In other words, when the focal point CP of the processing light EL is formed at or near the opening 721, a larger proportion of the light components of the processing light EL pass through the opening 721 (i.e., pass through the beam splitter 72), compared to when the focal point CP of the processing light EL is not formed at or near the opening 721. Here, if the beam cross section of the processing light EL at the opening 721 is made smaller than the area of ​​the opening 721, loss of light quantity of the processing light EL can be eliminated. In other words, when the focal point CP of the processing light EL is formed at or near the opening 721, the proportion of the light components of the processing light EL that are blocked by the beam splitting member 72 is smaller than when the focal point CP of the processing light EL is not formed at or near the opening 721. As a result, when the focal point CP of the processing light EL is formed at or near the opening 721, the proportion of the light components of the processing light EL that are irradiated onto the material layer ML via the beam splitting member 72 is larger than when the focal point CP of the processing light EL is not formed at or near the opening 721.Therefore, even when the beam scanning device 7 irradiates the material layer ML with the processing light EL through the beam branching member 72 having the opening 721, the beam scanning device 7 can irradiate the material layer ML with the processing light EL that is not attenuated (in other words, not blocked) by the beam branching member 72. As a result, the beam scanning device 7 can appropriately melt the material layer ML using the processing light EL that is not attenuated (in other words, not blocked) by the beam branching member 72.

[0040] 2 , the processing light EL that has passed through the beam splitter 72 is incident on the focusing optical system 73. The focusing optical system 73 is an optical system that focuses the processing light EL that has entered the focusing optical system 73. Specifically, the focusing optical system 71 is an optical system that focuses the processing light EL that has entered the beam scanning device 7 onto the material layer ML.

[0041] In particular, in this embodiment, the processing light EL in a diverging state is incident on the collecting optical system 73. That is, the processing light EL, which is diverging light, is incident on the collecting optical system 73. In this case, the collecting optical system 73 collects the processing light EL that is incident on the collecting optical system 73 in a diverging state. That is, the collecting optical system 73 collects the processing light EL, which is diverging light.

[0042] However, the focusing optical system 73 may focus the processing light EL that is incident on the focusing optical system 73 in a convergent state (convergent state). That is, the focusing optical system 73 may focus the processing light EL that is convergent light (convergent light). Alternatively, the focusing optical system 73 may focus the processing light EL that is incident on the beam scanning device 7 as parallel light. That is, the focusing optical system 73 may focus the processing light EL that is parallel light.

[0043] The condensing optical system 73 includes a focus-changing optical system 731, a magnification-changing optical system 732, and a condensing lens 733. The focus-changing optical system 731 may be referred to as a focus-changing member, and the magnification-changing optical system 732 may be referred to as a magnification-changing member.

[0044] The focus change optical system 731 is an optical system that can change the focus position FP of the processing light EL emitted from the focusing optical system 73. In particular, the focus change optical system 731 is an optical system that can change the focus position FP of the processing light EL emitted from the focusing optical system 73 along the optical axis of the focusing optical system 73. In the example shown in FIG. 2 , the optical axis of the focusing optical system 73 is an axis along the Y axis. Note that the focus position FP of the processing light EL emitted from the focusing optical system 73 may be a focusing position where a focusing point of the processing light EL emitted from the focusing optical system 73 is formed. The focus position FP of the processing light EL emitted from the focusing optical system 73 may be a convergence position where the processing light EL emitted from the focusing optical system 73 is most convergent.

[0045] In order to adjust the focus position FP of the processing light EL, the focus change optical system 731 may include two lenses, including at least one movable lens that is movable along the optical axis of the condensing optical system 73. In this case, the focus change optical system 731 may change the focus position FP of the processing light EL by moving the at least one movable lens along the optical axis of the condensing optical system 73. Note that in the example shown in Figure 2, the focus change optical system 731 includes two lenses, including one movable lens 7311 that is movable along the optical axis of the condensing optical system 73, and one fixed lens 7312 that does not need to be movable along the optical axis of the condensing optical system 73.

[0046] The focus-changing optical system 731 may change the focus position FP of the processing light EL so that the focus position FP of the processing light EL is located at a desired position. In particular, the focus-changing optical system 731 may change the focus position FP of the processing light EL so that the focus position FP of the processing light EL is located at a desired position even when the beam scanning device 7 scans the material layer ML with the processing light EL. For example, the focus-changing optical system 731 may change the focus position FP of the processing light EL so that the focus position FP of the processing light EL continues to be located at a desired position even when the beam scanning device 7 scans the material layer ML with the processing light EL. In other words, the focus-changing optical system 731 may change the focus position FP of the processing light EL in conjunction with (or synchronized with) the scanning of the processing light EL by the beam scanning device 7 so that the focus position FP of the processing light EL is located at a desired position. For example, the focus changing optical system 731 may change the focus position FP of the processing light EL in conjunction with the scanning of the processing light EL by the beam scanning device 7 so that the focus position FP of the processing light EL remains positioned at the desired position.

[0047] The magnification changing optical system 732 is an optical system that can change the spot size of the processing light EL. The spot size of the processing light EL may refer to the size of the beam spot formed by the processing light EL on the surface of the material layer ML (i.e., the processing surface MLs) irradiated with the processing light EL. That is, the spot size of the processing light EL may refer to the size of the irradiation area (i.e., the beam spot) irradiated with the processing light EL on the surface of the material layer ML (i.e., the processing surface MLs). In other words, the spot size of the processing light EL may refer to the size of the irradiation area of ​​the processing light EL on the surface of the material layer ML (i.e., the processing surface MLs).

[0048] The magnification changing optical system 732 may change the spot size of the processing light EL so that the spot size of the processing light EL becomes a desired size. In particular, the magnification changing optical system 732 may change the spot size of the processing light EL so that the spot size of the processing light EL becomes a desired size even when the beam scanning device 7 scans the material layer ML with the processing light EL. In other words, the magnification changing optical system 732 may change the spot size of the processing light EL in conjunction with the scanning of the processing light EL by the beam scanning device 7 so that the spot size of the processing light EL becomes a desired size.

[0049] The desired size may be fixed. In this case, the spot size of the processing light EL irradiated at a first position on the processing surface MLs may be the same as the spot size of the processing light EL irradiated at a second position on the processing surface MLs different from the first position. Alternatively, the desired size may be changed in conjunction with the scanning of the processing light EL by the beam scanning device 7. In this case, the spot size of the processing light EL irradiated at the first position on the processing surface MLs may be different from the spot size of the processing light EL irradiated at a second position on the processing surface MLs different from the first position.

[0050] The focusing optical system 73 may change the focus position FP of the processing light EL and the spot size of the processing light EL in conjunction with each other using the focus change optical system 731 and the magnification change optical system 732. In other words, the focusing optical system 73 may change the focus position FP of the processing light EL and the spot size of the processing light EL in synchronization with each other using the focus change optical system 731 and the magnification change optical system 732. As an example, the focusing optical system 73 may change the focus position FP of the processing light EL and the spot size of the processing light EL in conjunction with each other so that the focus position FP of the processing light EL is located at a desired position and the spot size of the processing light EL becomes a desired size.

[0051] Specifically, as described in detail below, the focusing optical system 73 uses the scanning optical element 74 to scan the surface of the material layer ML (i.e., the processing surface MLs) with the processing light EL. That is, the focusing optical system 73 uses the scanning optical element 74 to move the irradiation area irradiated with the processing light EL on the surface of the material layer ML (i.e., the processing surface MLs). In this case, if the focus position FP of the processing light EL remains fixed, the state of the focusing optical system 73 may fluctuate between a first state in which the material layer ML is irradiated with the focused processing light EL and a second state in which the material layer ML is irradiated with the defocused processing light EL in accordance with the scanning of the processing light EL by the scanning optical element 74. The focused state may also refer to a state in which the focus position FP of the processing light EL is located at or near the surface of the uppermost material layer ML (i.e., the processing surface MLs). The defocused state may refer to a state in which the focus position FP of the processing light EL is more than a certain distance away from the surface of the uppermost material layer ML (i.e., the processing surface MLs) or its vicinity. As a result, due to the difference between the intensity of the processing light EL in the defocused state at the surface of the material layer ML and the intensity of the processing light EL in the focused state at the surface of the material layer ML, the intensity of the processing light EL may unintentionally fluctuate on the surface of the material layer ML in accordance with the scanning of the processing light EL by the scanning optical element 74. Such fluctuations in the intensity of the processing light EL may lead to a deterioration in shaping accuracy. Therefore, the focusing optical system 73 may change the focus position FP of the processing light EL in conjunction with the scanning of the processing light EL by the scanning optical element 74 so that the focus position FP of the processing light EL is located on or near the surface of the uppermost material layer ML. In other words, the focusing optical system 73 may change the focus position FP of the processing light EL in conjunction with the scanning of the processing light EL by the scanning optical element 74 so that the focus position FP of the processing light EL is located on or near the processing surface MLs. As a result, the intensity of the processing light EL is less likely to unintentionally fluctuate on the surface of the material layer ML in accordance with the scanning of the processing light EL by the scanning optical member 74. As a result, the processing system 1 can form a three-dimensional structure with high modeling accuracy.

[0052] The focusing optical system 73 may change the focus position FP of the processing light EL and the spot size of the processing light EL in conjunction with each other so that the spot size of the processing light EL remains constant even when the focus position FP of the processing light EL is changed. Specifically, fluctuations in the spot size of the processing light EL on the surface of the material layer ML lead to fluctuations in the intensity of the processing light EL on the surface of the material layer ML. This is because the larger the spot size, the smaller the intensity of the processing light EL per unit area (i.e., the influence of the processing light EL). Therefore, the focusing optical system 73 may change the focus position FP of the processing light EL and the spot size of the processing light EL in conjunction with the scanning of the processing light EL by the scanning optical member 74 so that the focus position FP of the processing light EL is located at or near the surface of the uppermost material layer ML and the spot size of the processing light EL remains constant. In other words, the focusing optical system 73 may change the spot size of the processing light EL so that the spot size of the processing light EL is maintained constant in conjunction with the change in the focus position FP of the processing light EL by the focus change optical system 731. As a result, there is little possibility that the intensity of the processing light EL will unintentionally fluctuate on the surface of the material layer ML in accordance with the scanning of the processing light EL by the scanning optical member 74. As a result, the processing system 1 can form a three-dimensional structure with high forming accuracy.

[0053] The processing light EL that has passed through the focus change optical system 731 and the magnification change optical system 732 is incident on the condenser lens 733. That is, the processing light EL from the focus change optical system 731 and the magnification change optical system 732 is incident on the condenser lens 733. The condenser lens 733 condenses the processing light EL that has entered the condenser lens 733 onto the material layer ML. Note that the optical axis of the condenser optical system 73 may refer to the optical axis of the condenser lens 733, which is the final optical element of the condenser optical system 73.

[0054] The processing light EL emitted from the condensing optical system 73 is incident on the scanning optical member 74. That is, the processing light EL from the condensing optical system 73 is incident on the scanning optical member 74.

[0055] The scanning optical member 74 scans the processing light EL incident on the scanning optical member 74 from the focusing optical system 73. Specifically, the scanning optical member 74 scans the surface of the material layer ML (i.e., the processing surface MLs) with the processing light EL. That is, the scanning optical member 74 moves the irradiation area irradiated with the processing light EL on the surface of the material layer ML (i.e., the processing surface MLs).

[0056] 2 shows an example in which the scanning optical member 74 is a galvanometer mirror. The galvanometer mirror is an optical member that deflects the processing light EL to change the emission direction of the processing light EL emitted from the galvanometer mirror. For this reason, the galvanometer mirror (i.e., the scanning optical member 74) may also be referred to as a deflection optical system.

[0057] The scanning optical member 74, which is a galvanometer mirror, may include a scanning mirror 741 and a scanning mirror 742. The processing light EL from the focusing optical system 73 is incident on the scanning mirror 741. The scanning mirror 741 reflects the processing light EL incident on the scanning mirror 741 toward the scanning mirror 742. The scanning mirror 742 reflects the processing light EL incident on the scanning mirror 742 toward the material layer ML.

[0058] The scanning mirror 741 may be oscillated or rotated around a rotation axis along either the X-axis or the Y-axis by an actuator (not shown). In this case, the oscillation or rotation of the scanning mirror 741 causes the processing light EL to scan the surface of the material layer ML along either the X-axis direction or the Y-axis direction. In other words, the irradiation area irradiated with the processing light EL moves on the surface of the material layer ML along either the X-axis direction or the Y-axis direction.

[0059] The scanning mirror 742 may be swung or rotated around a rotation axis along the other of the X-axis and the Y-axis by an actuator (not shown). In this case, the swinging or rotation of the scanning mirror 742 causes the processing light EL to scan the surface of the material layer ML along the other of the X-axis direction and the Y-axis direction. In other words, the irradiation area irradiated with the processing light EL moves on the surface of the material layer ML along the other of the X-axis direction and the Y-axis direction.

[0060] The scanning optical member 74 may be any optical member other than a galvanometer mirror that can scan the processing light EL. For example, the scanning optical member 74 may be at least one of a polygon mirror and a resonant mirror.

[0061] The scanning optical member 74 emits the processing light EL downward from the scanning optical member 74. As a result, the processing light EL emitted from the scanning optical member 74 is emitted toward the outside of the beam scanning device 7. The processing light EL emitted from the scanning optical member 74 is emitted toward the material layer ML located below the beam scanning device 7. The processing light EL emitted from the beam scanning device 7 is irradiated onto the material layer ML. As a result, as described above, the structure layer SL is formed.

[0062] 5 showing the configuration of the beam scanning device 7, light received by a light receiving device 76 may be incident on the beam scanning device 7. Specifically, as will be described in detail later, the control device 3 observes (in other words, monitors) the status of the formation of the three-dimensional structure by the processing device 2 based on the light reception result of the light receiving device 76. For this reason, light that can be used to observe (in other words, monitor) the status of the formation of the three-dimensional structure by the processing device 2 may be incident on the beam scanning device 7 as light received by the light receiving device 76.

[0063] As an example, because a three-dimensional structure is formed from the material layer ML, light from the material layer ML, which is the observation target (object to be observed), may be incident on the beam scanning device 7 as the light received by the light receiving device 76. Light from the surface (i.e., the processing surface MLs) of the material layer ML, which is the observation target (object to be observed), may be incident on the beam scanning device 7 as the light received by the light receiving device 76. For example, scattered light from the surface (i.e., the processing surface MLs) of the material layer ML irradiated with the processing light EL may be incident on the beam scanning device 7 as the light received by the light receiving device 76. In other words, the processing light EL scattered by the material layer ML (i.e., scattered light of the processing light EL) may be incident on the beam scanning device 7 as the light received by the light receiving device 76. For example, light generated on the surface (i.e., the processing surface MLs) of the material layer ML due to the processing light EL may be incident on the beam scanning device 7 as the light received by the light receiving device 76. The light generated on the surface of the material layer ML due to the processing light EL may include the above-described scattered light of the processing light EL. The light generated on the surface of the material layer ML due to the processing light EL may also include the processing light EL reflected by the material layer ML (i.e., the reflected light of the processing light EL).

[0064] As described above, when the processing light EL is irradiated onto the surface of the material layer ML (i.e., the processing surface MLs), a molten pool MP is formed on the surface of the material layer ML (i.e., the processing surface MLs). Therefore, light from the molten pool MP to be observed may be incident on the beam scanning device 7 as the light received by the light receiving device 76. Note that radiant light from the surface of the material layer ML may also be incident on the beam scanning device 7.

[0065] As another example, light from the three-dimensional structure itself, which is the observation target (object to be observed), may be incident on the beam scanning device 7 as light received by the light receiving device 76. As another example, because the three-dimensional structure includes a structural layer SL, light from the structural layer SL, which is the observation target, may be incident on the beam scanning device 7 as light received by the light receiving device 76.

[0066] In the following description, for convenience of explanation, the light received by the light receiving device 76 (e.g., light that can be used to observe the status of the formation of a three-dimensional structure by the processing device 2) and incident on the beam scanning device 7 will be referred to as observation light OL. In other words, light from the object to be observed will be referred to as observation light OL. The configuration of the beam scanning device 7 shown in Fig. 5 is the same as the configuration of the beam scanning device 7 shown in Fig. 2, but the two differ in that Fig. 5 shows the configuration of the beam scanning device 7 together with the optical path of the observation light OL, while Fig. 2 shows the configuration of the beam scanning device 7 together with the optical path of the processing light EL.

[0067] The wavelength band of the observation light OL is different from the wavelength band of the processing light EL. Specifically, as described above, the processing light EL is light in a first wavelength band having a peak wavelength of 1000 nm or a wavelength close to 1000 nm. On the other hand, the observation light OL may be light in a second wavelength band from 400 nm to 800 nm. In other words, the observation light OL may be visible light. For example, when the observation light OL includes reflected light of ambient light from the object being observed, the observation light OL may usually include visible light. Furthermore, the observation light OL may include radiant light having a wavelength longer than 1000 nm generated from the molten pool MP.

[0068] In the following description, an example will be described in which the wavelength band of the observation light OL is a shorter wavelength band than the wavelength band of the processed light EL. That is, an example will be described in which the wavelength band of the processed light EL is a longer wavelength band than the wavelength band of the observation light OL. However, the wavelength band of the processed light EL may also be a shorter wavelength band than the wavelength band of the observation light OL. The wavelength band of the processed light EL may also at least partially overlap with the wavelength band of the observation light OL.

[0069] The observation light OL incident on the beam scanning device 7 is incident on the scanning optical member 74. Specifically, the observation light OL incident on the beam scanning device 7 is incident on the scanning mirror 742 of the scanning optical member 74. The scanning mirror 742 reflects the observation light OL incident on the scanning mirror 742 toward the scanning mirror 741. As a result, the observation light OL reflected by the scanning mirror 742 is incident on the scanning mirror 741. The scanning mirror 741 reflects the observation light OL incident on the scanning mirror 741 toward the beam splitter 72. As a result, the observation light OL reflected by the scanning mirror 741 is incident on the focusing optical system 73. The observation light OL incident on the focusing optical system 73 passes through the focusing optical system 73. The observation light OL passing through the focusing optical system 73 is incident on the beam splitter 72.

[0070] The beam splitting member 72 reflects at least a portion of the observation light OL incident on the beam splitting member 72. Typically, the beam splitting member 72 reflects most of the observation light OL, excluding a portion of the incident light. Specifically, as shown in FIG. 6( a ), which is a perspective view showing the beam splitting member 72 on which the observation light OL is incident, and FIG. 6( b ), which is a cross-sectional view showing the beam splitting member 72 on which the observation light OL is incident, a reflective film 7221 capable of reflecting the observation light OL is formed on at least a portion of the surface of the beam splitting member 72 (particularly, the surface on which the observation light OL described below is incident; in the example shown in FIGS. 6( a ) and 6( b ), the surface on the −Y side). In other words, the surface portion of the surface of the beam splitting member 72 on which the reflective film 7221 is formed functions as a reflective surface 722. The reflective surface 722 may also be referred to as a light reflecting portion. As shown in FIGS. 6( a ) and 6( b ), at least a portion of the observation light OL incident on the beam splitting member 72 is reflected by the reflective surface 722. Specifically, at least a portion of the observation light OL incident on the beam splitter 72 is reflected by the reflecting surface 722 toward the light receiving device 76. In other words, the observation light OL reflected by the reflecting surface 722 is directed toward the light receiving device 76.

[0071] As described above, the beam splitting member 72 has an opening 721 through which the processing light EL can pass. In this case, the observation light OL may also pass through the opening 721. As a result, the light receiving device 76 may not be able to receive the observation light OL that has passed through the opening 721. However, as shown in FIGS. 6A and 6B , the reflective film 7221 is formed at a position different from the position at which the opening 721 is formed. That is, the reflective surface 722 that can function as a light reflector is formed at a position different from the opening 721. In this case, even if a portion of the observation light OL that has entered the beam splitting member 72 enters the opening 721, it is highly likely that another portion of the observation light OL that has entered the beam splitting member 72 will be incident on the reflective surface 722 that is formed at a position different from the opening 721. Therefore, even if the beam splitting member 72 has an opening 721, at least a portion of the observation light OL that has entered the beam splitting member 72 is reflected by the reflective surface 722 that is formed at a position different from the opening 721. Specifically, the observation light OL incident on the reflecting surface 722 is reflected by the reflecting surface 722, which is formed at a position different from the opening 721. Therefore, even if the beam splitting member 72 has the opening 721, the beam splitting member 72 can reflect at least a portion of the observation light OL incident on the beam splitting member 72 toward the light receiving device 76.

[0072] However, as shown in Fig. 7(a) which is a perspective view showing the beam splitting member 72 onto which the observation light OL is incident and Fig. 7(b) which is a cross-sectional view showing the beam splitting member 72 onto which the observation light OL is incident, the observation light OL incident on the beam splitting member 72 may be incident on the reflecting surface 722 but may not be incident on the opening 721. In other words, the observation light OL incident on the beam splitting member 72 may be incident on a position along the reflecting surface 722 away from the opening 721. Even in this case, the beam splitting member 72 can reflect at least a portion of the observation light OL incident on the beam splitting member 72 towards the light receiving device 76.

[0073] 5 , the observation light OL reflected by the beam splitter 72 is incident on the light receiving device 76 via the observation optical system 75. However, the observation light OL reflected by the beam splitter 72 may also be incident on the light receiving device 76 without passing through the observation optical system 75.

[0074] The light receiving device 76 receives the observation light OL that is incident on the light receiving device 76. The light receiving device 76 outputs the result of receiving the observation light OL by the light receiving device 76 to the control device 3. The control device 3 may control the processing device 2 based on the result of receiving the observation light OL by the light receiving device 76.

[0075] As an example, the control device 3 may observe (in other words, monitor) the status of the formation of the three-dimensional structure by the processing device 2 based on the reception result of the observation light OL by the light-receiving device 76. Furthermore, the control device 3 may control the processing device 2 so as to appropriately form the three-dimensional structure based on the observation result (in other words, the monitoring result) of the status of the formation of the three-dimensional structure by the processing device 2. In other words, the control device 3 may control the processing device 2 so as to appropriately form the three-dimensional structure based on the reception result of the observation light OL by the light-receiving device 76.

[0076] An example of the light-receiving device 76 may be an imaging device (i.e., a camera) capable of capturing an image of the observation target. In this case, the light-receiving device 76 may output an observation image generated by the light-receiving device 76 capturing an image of the observation target as a result of receiving the observation light OL by the light-receiving device 76. The control device 3 may observe (in other words, monitor) the status of the formation of the three-dimensional structure by the processing device 2 based on the observation image generated by the light-receiving device 76. The control device 3 may control the processing device 2 so as to appropriately form the three-dimensional structure based on the observation image generated by the light-receiving device 76.

[0077] The light receiving device 76 may capture an image of the material layer ML irradiated with the processing light EL. More specifically, the light receiving device 76 may capture an image of the processing surface MLs irradiated with the processing light EL. In this case, the light receiving device 76 may generate an observation image that reflects the processing surface MLs. In particular, the light receiving device 76 may capture an image of the processing surface MLs, thereby capturing an image of the molten pool MP formed on the processing surface MLs. In this case, the light receiving device 76 may generate an observation image that reflects the molten pool MP.

[0078] When the light receiving device 76 images the machining surface MLs (e.g., images the molten pool MP), the machining surface MLs and the beam splitter 72, which reflects the observation light OL from the machining surface MLs toward the light receiving device 76, may be optically conjugate with each other with respect to the focusing optical system 73. For example, the machining surface MLs and the opening 721 of the beam splitter 72 may be optically conjugate with each other with respect to the focusing optical system 73. In this case, the focusing optical system 73 may form an image of the machining surface MLs (e.g., an image of the molten pool MP) at a position where the beam splitter 72 is disposed. For example, the focusing optical system 73 may form an image of the machining surface MLs (e.g., an image of the molten pool MP) at a position where the opening 721 of the beam splitter 72 is disposed.

[0079] However, the focusing optical system 73 may form an image of the machining surface MLs (e.g., an image of the molten pool MP) at a position separated along the optical axis of the focusing optical system 73 from the position where the beam branching member 72 is disposed. That is, the focusing optical system 73 may form an image of the machining surface MLs (e.g., an image of the molten pool MP) at a position defocused from the position where the beam branching member 72 is disposed. For example, the focusing optical system 73 may form an image of the machining surface MLs (e.g., an image of the molten pool MP) at a position separated along the optical axis of the focusing optical system 73 from the position where the opening 721 of the beam branching member 72 is disposed. That is, the focusing optical system 73 may form an image of the machining surface MLs (e.g., an image of the molten pool MP) at a position defocused from the position where the opening 721 of the beam branching member 72 is disposed.

[0080] In either case, the focusing optical system 73 may be considered to form an image of the machining surface MLs (e.g., an image of the molten pool MP) in the vicinity of the beam branching member 72. For example, the focusing optical system 73 may be considered to form an image of the machining surface MLs (e.g., an image of the molten pool MP) in the vicinity of the opening 721 of the beam branching member 72. For example, the focusing optical system 73 may be considered to form an image of the machining surface MLs (e.g., an image of the molten pool MP) in the vicinity of the reflecting surface 722 of the beam branching member 72.

[0081] Furthermore, when the light receiving device 76 images the machining surface MLs (e.g., images the molten pool MP), the machining surface MLs and the light receiving device 76 that receives the observation light OL from the machining surface MLs and images the machining surface MLs may be optically conjugate. As a result, the light receiving device 76 can appropriately generate an observation image in which the machining surface MLs is reflected (e.g., in which the molten pool MP is reflected). Note that, as described above, when the machining surface MLs and the beam splitter 72 are optically conjugate with respect to the focusing optical system 73, the beam splitter 72 that reflects the observation light OL from the machining surface MLs toward the light receiving device 76 and the light receiving device 76 may be optically conjugate with respect to the observation optical system 75. For example, the opening 721 of the beam splitter 72 and the light receiving device 76 may be optically conjugate with respect to the observation optical system 75. As a result, the machining surface MLs and the light receiving device 76 are optically conjugate. However, the processing surface MLs and the light receiving device 76 do not have to be optically conjugate.

[0082] An example of an observation image in which the molten pool MP is reflected is shown in FIG. 8 . As shown in FIG. 8 , the molten pool MP may be reflected in the observation image. In this case, the control device 3 may calculate the characteristics of the molten pool MP based on the observation image and control the machining device 2 based on the calculation results of the characteristics of the molten pool MP. For example, as shown in FIG. 8 , the control device 3 may calculate the size (e.g., diameter) MPS of the molten pool MP based on the observation image and control the machining device 2 based on the calculation results of the size MPS of the molten pool MP. As an example, the control device 3 may control the machining device 2 based on the calculation results of the size MPS of the molten pool MP so that the size MPS of the molten pool MP formed on the machining surface MLs is a desired size.

[0083] As described above, the observation light OL incident on the opening 721 of the beam splitter 72 is not reflected by the beam splitter 72. As a result, the observation light OL incident on the opening 721 of the beam splitter 72 is not received by the light receiving device 76, as also described above. In this case, as shown in Fig. 8 , an image portion corresponding to the opening 721 may appear in the observation image. For example, as shown in Fig. 8 , a blackened image portion may appear in the observation image as the image portion corresponding to the opening 721.

[0084] When the image portion corresponding to the opening 721 is reflected in the observation image, if the size of the image of the molten pool MP formed by the focusing optical system 73 near the beam branching member 72 is smaller than the size of the opening 721, the molten pool MP may not be reflected in the observation image. This is because most or all of the light components of the observation light OL from the molten pool MP may be incident on the opening 721. Therefore, the focusing optical system 73 may form the image of the molten pool MP near the beam branching member 72 so that the size of the image of the molten pool MP formed by the focusing optical system 73 near the beam branching member 72 is larger than the size of the opening 721. For example, the magnification of the focusing optical system 73 may be set so that the size of the image of the molten pool MP formed by the focusing optical system 73 near the beam branching member 72 is larger than the size of the opening 721. For example, by utilizing the chromatic aberration of the focusing optical system 73 to make the size of the image of the molten pool MP larger than the size of the beam cross section of the processing light EL passing through the opening 721, the size of the image of the molten pool MP can be made larger than the size of the opening 721. As a result, the molten pool MP is properly captured in the observation image. Note that FIG. 8 shows an example of an observation image generated by the light-receiving device 76 under conditions in which the size of the image of the molten pool MP formed by the focusing optical system 73 near the beam branching member 72 is larger than the size of the opening 721. As shown in FIG. 8, because the size of the image of the molten pool MP formed by the focusing optical system 73 near the beam branching member 72 is larger than the size of the opening 721, the size of the image of the molten pool MP in the observation image is also larger than the size of the opening 721. Typically, the energy transmitted from the processing light EL to the material layer ML is diffused within the material layer ML, so the size of the molten pool MP formed on the surface of the material layer ML (machining surface MLs) is larger than the size of the irradiation area of ​​the processing light EL irradiated on the surface of the material layer ML (machining surface MLs). Therefore, even if the focusing optical system 73 is an ideal optical system, the size of the image of the molten pool MP will be larger than the size of the opening 721.

[0085] As shown in FIG. 8 , the observation image may show the molten pool MP with its center separated from the image portion corresponding to the opening 721 in a direction corresponding to the scanning direction of the processing light EL on the processing surface MLs. The reason for this is as follows: As described above, the beam scanning device 7 (particularly the scanning optical member 74) scans the processing surface MLs with the processing light EL, resulting in the formation of the molten pool MP at the position on the processing surface MLs irradiated with the processing light EL. Here, the melting timing at which the molten pool MP is formed at the position on the processing surface MLs irradiated with the processing light EL is slightly delayed relative to the irradiation timing at which the processing light EL is irradiated on that portion of the processing surface MLs. This is because it takes a certain amount of time, albeit short, from the time the processing light EL is irradiated on that portion of the processing surface MLs until the energy of the processing light EL irradiated on that portion of the processing surface MLs actually melts the material layer ML. Thus, under conditions in which the melting timing is slightly delayed relative to the irradiation timing, the irradiation area of ​​the processing light EL continues to move on the processing surface MLs due to the scanning of the beam scanning device 7 (particularly the scanning optical member 74). Therefore, if we focus on the instantaneous timing, the position on the processing surface MLs where the processing light EL is actually irradiated differs from the position where the molten pool MP is actually formed. Furthermore, because the processing light EL passes through the opening 721 and is irradiated onto the processing surface MLs, the observation light OL (e.g., the specularly reflected light of the processing light EL by the processing surface MLs) from the position where the processing light EL is actually irradiated is likely to enter the opening 721. Therefore, in the observation image, an image portion corresponding to the opening 721 is captured at a position on the processing surface MLs where the processing light EL is actually irradiated, and the molten pool MP is captured at a position on the processing surface MLs where the molten pool MP is actually formed. As a result, due to the difference between the position on the machining surface MLs where the processing light EL is actually irradiated and the position where the molten pool MP is actually formed, the center of the molten pool MP in the observation image may move away from the image portion corresponding to the opening 721 along a direction corresponding to the scanning direction of the processing light EL on the machining surface MLs.In this way, even if the center of the molten pool MP in the observation image is away from the image portion corresponding to the opening 721, the molten pool MP still appears in the observation image. Therefore, the control device 3 is still able to calculate the characteristics of the molten pool MP based on the observation image.

[0086] Furthermore, considering that the observation light OL (particularly the specularly reflected light of the processing light EL by the processing surface MLs) from the position where the processing light EL is actually irradiated is likely to be incident on the opening 721, the scattered light of the processing light EL by the processing surface MLs (or the ±Nth (where N is an integer greater than or equal to 1)-order reflected light) may be incident on the periphery of the opening 721. In this case, an image formed by the scattered light of the processing light EL by the processing surface MLs (or the ±Nth-order reflected light) may be reflected in the periphery of the image portion corresponding to the opening 721 in the observation image.

[0087] (3) Technical Effects of the Processing System 1 As described above, in this embodiment, the beam scanning device 7 can appropriately scan the processing light EL using the scanning optical member 74. Therefore, the processing system 1 can appropriately perform additional processing using the beam scanning device 7. In other words, the processing system 1 can appropriately form a three-dimensional structure using the beam scanning device 7.

[0088] Furthermore, in this embodiment, the beam scanning device 7 uses a beam splitter 72 having an opening 721 and a reflecting surface 722 to irradiate the processing light EL onto the processing surface MLs and receive the observation light OL from the processing surface MLs irradiated with the processing light EL. Specifically, the beam scanning device 7 irradiates the processing light EL onto the processing surface MLs through the opening 721 of the beam splitter 72. Furthermore, the beam scanning device 7 uses the reflecting surface 722 of the beam splitter 72 to separate the observation light OL, which propagates along the same optical path as the processing light EL and enters the beam splitter 72, from the processing light EL and then receives the observation light OL. Therefore, the processing apparatus 2 can form a three-dimensional object by irradiating the processing light EL onto the processing surface MLs, and can observe (in other words, monitor) the status of the formation of the three-dimensional object by receiving the observation light OL. In this embodiment, the reflecting surface 722 of the beam splitter 72 can be one that does not have wavelength dependency, and therefore the observation light OL, which has the same wavelength as the processing light EL, can be reflected toward the light receiving device 76. Therefore, the light receiving device 76 can measure physical quantities such as the temperature of the molten pool MP.

[0089] (4) Modifications The configuration of the processing system 1 shown in Fig. 1 is merely an example. Therefore, the processing system 1 may have a configuration different from the configuration shown in Fig. 1. For example, the processing system 1 may have any configuration as long as the processing system 1 includes the beam scanning device 7 (including modifications thereof). For example, the processing system 1 may have any configuration as long as the processing system 1 can perform additional processing using the processing light EL from the beam scanning device 7 (including modifications thereof).

[0090] As an example, in the above description, the processing apparatus 2 includes a single beam scanning device 7. However, as shown in FIG. 9, which is a cross-sectional view illustrating the configuration of the processing apparatus 2 in a modified example, the processing apparatus 2 may include multiple beam scanning devices 7. Although FIG. 9 illustrates an example in which the processing apparatus 2 includes two beam scanning devices 7, the processing apparatus 2 may include three or more beam scanning devices 7. In this case, the processing apparatus 2 may irradiate the material layer ML (processing surface MLs) with multiple processing light beams EL emitted from the multiple beam scanning devices 7. In particular, the processing apparatus 2 may simultaneously irradiate the processing surface MLs with multiple processing light beams EL. In other words, the processing apparatus 2 may simultaneously scan the processing surface MLs with multiple processing light beams EL. In this case, the area scanned by one processing light beam EL and the area scanned by another processing light beam EL different from the one processing light beam EL may at least partially overlap, or may not overlap. In this way, the processing apparatus 2 including multiple beam scanning devices 7 can perform additional processing using multiple processing light beams EL. Therefore, the throughput of the additional processing is improved compared to when additional processing is performed using a single processing light EL. For example, the time required to form a three-dimensional structure is shortened.

[0091] In the above description, the condenser lens 733 of the beam scanning device 7 is disposed in the optical path between the beam splitter 72 and the scanning optical member 74. However, the condenser lens 733, which is part of the condenser optical system 73, may be disposed on the exit side of the scanning optical member 74. That is, the condenser lens 733 may be disposed on the processing surface MLs side of the scanning optical member 74. In this case, the condenser lens 733 may include an fθ lens. Furthermore, the scanning optical member 74 may be disposed near the front focal position of the condenser lens 733 (near the pupil plane of the condenser lens 733), and the processing light EL from the focus changing optical system 731 and the magnification changing optical system 732 may be a parallel beam. In this case, the focus changing optical system 731 does not need to change the focus position FP in response to the scanning of the processing light EL by the scanning optical member 74.

[0092] In the above description, the beam splitting member 72 is configured from a plate-shaped member. However, the beam splitting member 72 does not have to be configured from a plate-shaped member. For example, as shown in FIGS. 10( a) and 10(b), the beam splitting member 72 may be configured from a plurality of triangular prism-shaped light-transmitting members. For example, as shown in FIGS. 10(a) and 10(b), the beam splitting member 72 may include triangular prism-shaped light-transmitting members 7241 and 7242. A reflective film 7221 may be formed on a portion of the surface of one of the light-transmitting members 7241 (typically, a portion of the surface facing the other light-transmitting member 7242). A surface portion of the light-transmitting member 7241 on which the reflective film 7221 is not formed may function as a non-reflective surface 723 (non-reflective portion 7212). A surface portion of the light-transmitting member 7241 on which the reflective film 7221 is formed may function as a reflective surface 722. This non-reflective surface 723 may function as an opening 721. The reflective film 7221 may be formed on the other light transmitting member 7242. A gap may be formed between the light transmitting members 7241 and 7242, and the focal point CP of the processing light EL may be located in this gap.

[0093] In the above description, the processing system 1 melts the material layer ML by irradiating the material layer ML with processing light EL. However, the processing system 1 may melt the material layer ML by irradiating the material layer ML with any energy beam. Examples of the energy beam include at least one of a charged particle beam and an electromagnetic wave. Examples of the charged particle beam include at least one of an electron beam and an ion beam.

[0094] In the above description, the processing system 1 forms a three-dimensional structure by performing additive processing based on powder bed fusion (PBF). However, the processing system 1 may form a three-dimensional structure by performing additive processing according to other methods capable of forming a three-dimensional structure. Examples of other methods capable of forming a three-dimensional structure include at least one of a deposition method (DED: Directed Energy Deposition) such as laser metal deposition (LMD), a binder jetting method, a material jetting method, a stereolithography method, and a laser metal fusion method (LMF).

[0095] In the above description, the processing system 1 performs additive processing using the processing light EL emitted from the beam scanning device 7. However, the processing system 1 may also perform subtractive processing using the processing light EL emitted from the beam scanning device 7. For example, the processing system 1 may perform subtractive processing to remove a part of a workpiece (i.e., an object to be processed) by irradiating the workpiece with the processing light EL emitted from the beam scanning device 7.

[0096] The processing system 1 may perform a remelt process in addition to at least one of an additive process and a subtractive process. The remelt process may include a process for reducing the flatness of the surface of an object processed by at least one of an additive process and a subtractive process (for example, a three-dimensional structure formed by an additive process or a workpiece from which a portion has been removed by a subtractive process). Reducing the flatness of the surface of the object may be equivalent to at least one of reducing the surface roughness of the surface of the object and making the surface of the object closer to a flat surface.

[0097] At least some of the constituent elements of each of the above-described embodiments can be appropriately combined with at least some of the other constituent elements of each of the above-described embodiments. Some of the constituent elements of each of the above-described embodiments may not be used. Furthermore, to the extent permitted by law, the disclosures of all publications and U.S. patents cited in each of the above-described embodiments are incorporated herein by reference.

[0098] The present invention is not limited to the above-described embodiments, but can be modified as appropriate within the scope of the claims and the gist or concept of the invention as can be read from the entire specification, and beam scanning devices, processing devices, and processing methods involving such modifications are also included in the technical scope of the present invention.

[0099] REFERENCE SIGNS LIST 1 Processing system 2 Processing device 3 Control device 31 Arithmetic device 32 Storage device 7 Beam scanning device 71 Condensing optical system 72 Beam splitting member 721 Opening 7211 Aperture 7212 Non-reflecting portion 722 Reflecting surface 7221 Reflecting film 723 Non-reflecting surface 73 Condensing optical system 731 Focus changing optical system 732 Magnification changing optical system 733 Condenser lens 74 Scanning optical member 76 Light receiving device EL Processing light OL Observation light CP Focus point FP Focus position ML Material layer MLs Processing surface SL Structure layer

Claims

1. A beam scanning device for scanning a processing beam used in a processing machine, comprising: a first focusing optical system for focusing the processing beam incident on said beam scanning device; a beam splitting member through which the processing beam from said focusing optical system passes; a second focusing optical system for focusing the processing beam that has passed through said beam splitting member; and a scanning optical member for scanning the processing beam that has passed through said beam splitting member, wherein said beam splitting member comprises an optical member having an opening and a light reflecting portion disposed at different positions, and light incident through said scanning optical member is reflected by said light reflecting portion, and said first focusing optical system forms a focusing point at or near the position of said opening.

2. The beam scanning device according to claim 1, wherein the processing surface irradiated with the processing beam and the opening of the beam splitting member are optically conjugate with respect to the second focusing optical system.

3. A beam scanning device as described in claim 1, wherein the second focusing optical system forms an image of the processing surface irradiated with the processing beam at a position defocused from the opening of the beam splitting member.

4. A beam scanning device as claimed in any one of claims 1 to 3, wherein the processing beam forms a molten pool on the processing surface irradiated with the processing beam.

5. A beam scanning device as described in claim 4, wherein the second focusing optical system forms an image of the molten pool near the light reflecting portion of the beam branching member, and the magnification of the second focusing optical system is set so that the size of the image of the molten pool at the light reflecting portion is larger than the size of the opening.

6. A beam scanning device according to any one of claims 1 to 5, wherein the light reflected by the light reflecting portion of the beam splitting member is directed to a light receiving device.

7. The beam scanning device according to claim 6, wherein the light receiving device images the processing surface irradiated with the processing beam.

8. A beam scanning device according to any one of claims 1 to 7, wherein the second focusing optical system is provided with a focus changing member that changes the focus position of the processing beam.

9. The beam scanning device according to claim 8, wherein the scanning of the processing beam by the scanning optical member is linked to the change of the focus position.

10. A beam scanning device as claimed in any one of claims 1 to 9, wherein the second focusing optical system is provided with a magnification changing member that changes the size of the irradiation area of ​​the processing beam on the processing surface onto which the processing beam is irradiated.

11. A beam scanning device as claimed in any one of claims 1 to 10, wherein the beam splitting member receives scattered light at a processing surface irradiated with the processing beam, or light generated at the processing surface due to the processing beam.

12. A beam scanning device according to any one of claims 1 to 11, wherein a processing beam is incident on the scanning optical member via at least a part of the second focusing optical system.

13. A processing apparatus comprising the beam scanning device according to any one of claims 1 to 12, for processing an object using a processing beam from the beam scanning device.

14. A processing method comprising: irradiating an object with a processing beam from a beam scanning device according to any one of claims 1 to 12; and scanning the processing beam on the object.

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