Hologram data generation system and hologram data generation method

Abstract

To improve the hologram used in a spatial light modulator to be a more appropriate one.SOLUTION: A data generation system 10 for holograms generates data for holograms in order to realize the hologram that is used in modulating light in a spatial light modulator, said data generation system comprising: an acquisition unit 11 that acquires target information that indicates the intensity distribution of outgoing light that is the target of outgoing light from the hologram; a determination unit 12 that determines the generation method used in generating data for the hologram, in accordance with the type of intensity distribution that is indicated by the target information acquired by the acquisition unit 11; and a generation unit 13 that generates data for the hologram from the target information acquired by the acquisition unit 11, by using the generation method determined by the determination unit 12.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a hologram data generation system and a hologram data generation method for generating hologram data for realizing a hologram used for modulating light in a spatial light modulator.

Background Art

[0002] Conventionally, a spatial light modulator (SLM: Spatial Light Modulator) that modulates and emits the spatial phase distribution of light has been used in a laser processing machine or the like. In the spatial light modulator, light is modulated by a hologram (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As the hologram in the spatial light modulator, a computer-generated hologram (CGH: Computer Generated Hologram) generated by calculation on a computer is used. The distribution of the emitted light from the hologram can be various according to the purpose of use of the spatial light modulator or the like. However, if a hologram is generated by a uniform generation method (for example, a specific algorithm), the distribution of the emitted light from the hologram may not be appropriate according to the purpose of use or the like.

[0005] The present invention has been made in view of the above, and an object thereof is to provide a hologram data generation system and a hologram data generation method capable of making the hologram used in the spatial light modulator appropriate.

Means for Solving the Problems

[0006] To achieve the above objective, the hologram data generation system according to the present invention is a hologram data generation system for generating hologram data for realizing a hologram used for modulating light in a spatial light modulator, comprising: acquisition means for acquiring target information indicating the intensity distribution of emitted light, which is the target of the emitted light from the hologram; determination means for determining a generation method to be used for generating hologram data according to the type of intensity distribution indicated by the target information acquired by the acquisition means; and generation means for generating hologram data from the target information acquired by the acquisition means according to the generation method determined by the determination means.

[0007] In the hologram data generation system according to the present invention, hologram data is generated by an appropriate generation method according to the type of intensity distribution of the emitted light, which is the target of the emitted light from the hologram. Therefore, according to the hologram data generation system according to the present invention, it is possible to create a suitable hologram for use in a spatial light modulator.

[0008] The determination means may determine the type of intensity distribution from the intensity distribution indicated by the target information acquired by the acquisition means, and determine the generation method to be used to generate the hologram data according to the determined type. With this configuration, the generation method can be determined appropriately and reliably. As a result, it is possible to reliably make the hologram used in the spatial light modulator appropriate.

[0009] The intensity distribution may include at least one of discrete distributions, distributions in the direction of light propagation, and annular distributions. This configuration allows for the selection of an appropriate intensity distribution for determining the generation method. As a result, it is possible to reliably produce an appropriate hologram for use in a spatial light modulator.

[0010] Incidentally, in addition to being described as an invention of a data generation system for holograms as described above, the present invention can also be described as an invention of a method for generating data for holograms, as described below. These are substantially the same invention, differing only in category, and produce similar functions and effects.

[0011] In other words, the hologram data generation method according to the present invention is a hologram data generation method which is an operation method of a hologram data generation system that generates hologram data for realizing a hologram used for modulation of light in a spatial light modulator, and includes: an acquisition step of acquiring target information that indicates the intensity distribution of emitted light, which is the target of the emitted light from the hologram; a determination step of determining a generation method to be used for generating hologram data according to the type of intensity distribution indicated by the target information acquired in the acquisition step; and a generation step of generating hologram data from the target information acquired in the acquisition step using the generation method determined in the determination step. [Effects of the Invention]

[0012] According to the present invention, the hologram used in a spatial light modulator can be made appropriate. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows the configuration of a hologram data generation system according to an embodiment of the present invention. [Figure 2] This figure shows an example of the configuration of a laser processing machine that utilizes hologram data generated by a hologram data generation system. [Figure 3] This figure shows an example of target information acquired by a hologram data generation system. [Figure 4] This diagram schematically illustrates the generation of hologram data in a hologram data generation system. [Figure 5] This figure shows an example of target information acquired by a hologram data generation system. [Figure 6] This flowchart shows a hologram data generation method, which is a process performed in a hologram data generation system according to an embodiment of the present invention. [Figure 7] This is a flowchart showing the process for determining the type of intensity distribution. [Modes for carrying out the invention]

[0014] The embodiments of the hologram data generation system and hologram data generation method according to the present invention will be described in detail below with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant explanations are omitted.

[0015] Figure 1 shows the hologram data generation system 10 according to this embodiment. The hologram data generation system 10 is a system (device) that generates hologram data for realizing a hologram used for modulating light in an SLM (Spatial Light Modulator). An SLM is a device that receives light, modulates the spatial phase distribution of the incident light, and emits it. Hereafter, it will simply be referred to as modulating light.

[0016] In this embodiment, the SLM is used in a laser processing machine 20. Figure 2 schematically shows an example of the configuration of the laser processing machine 20. The laser processing machine 20 is configured to include an SLM module 30 which includes an SLM 31. Note that the SLM 31 does not necessarily have to be used in the laser processing machine 20, and may be used in any application other than laser processing, such as conventional applications.

[0017] The SLM31 has a plurality of pixel electrodes arranged in a two-dimensional manner, and realizes (generates) a hologram by the pixel electrodes. For example, the SLM31 realizes a hologram of 1280×1024 pixels (SXGA: Super Extended Graphics Array). The SLM31 modulates light by transmitting or reflecting the light incident on the hologram. The SLM31 is, for example, an LCOS (Liquid crystal on silicon)-SLM. Note that the SLM31 may be a conventional SLM that performs light modulation using a hologram.

[0018] As the hologram used for light modulation in the SLM31, CGH is used. The hologram data generation system 10 generates hologram data for realizing CGH. The SLM31 inputs the hologram data generated by the hologram data generation system 10 and uses it for realizing the hologram.

[0019] The hologram data generation system 10 is realized by a conventional computer including hardware such as a CPU (Central Processing Unit), a memory, and a communication module, for example. The hologram data generation system 10 may be a computer system including a plurality of computers. Each function of the hologram data generation system 10 described later is exhibited by these components operating according to a program or the like.

[0020] The hologram data generation system 10 is provided by, for example, a service provider that provides hologram data to the user of the SLM31, that is, the user of the laser processing machine 20. For example, the user concludes a subscription contract with the service provider and receives the provision of hologram data. In this case, the hologram data generation system 10 may be realized by a cloud server.

[0021] A user control device 40, such as a PC (personal computer), transmits data necessary for generating hologram data to a hologram data generation system 10 via a communication network such as the Internet. The hologram data generation system 10 receives the transmitted data and generates hologram data based on it. The hologram data generation system 10 transmits the generated hologram data to the control device 40. The control device 40 receives the transmitted hologram data and outputs it to the SLM 31. The functions of the control device 40 may also be implemented by dedicated client software.

[0022] In this way, if hologram data is generated and provided to the user by a service provider other than the user, the user does not need to generate the hologram data themselves and can easily use SLM31. For example, the user does not need to prepare software to generate hologram data individually or learn how to generate hologram data. Furthermore, the hologram data generation system 10 does not need to be provided within a framework using a cloud server provided by a service provider as described above, and may be provided within any framework as long as it has the configuration according to this embodiment.

[0023] The generation of hologram data by the hologram data generation system 10 is performed based on target information that indicates the intensity distribution of the emitted light, which is the target of the emitted light from the hologram. The hologram data generation system 10 creates appropriate hologram data according to the target information using the functions of this embodiment, which will be described later.

[0024] Next, an example of a laser processing machine 20 including an SLM 31 will be described. Figure 2 schematically shows the configuration of the laser processing machine 20 according to this embodiment. As shown in Figure 2, the laser processing machine 20 includes a laser light source 21, a beam shaping optical system 22, a lens 23, and an SLM module 30. The above components are positioned and arranged in the optical path of the light used for laser processing in the order of laser light source 21, beam shaping optical system 22, SLM module 30, and lens 23.

[0025] The laser light source 21 is a light source that outputs light (laser light) that is input to the SLM module 30 and used for laser processing. The beam shaping optical system 22 is an optical system that shapes the light output from the laser light source 21 into a laser beam suitable for input to the SLM module 30 and outputs it. The SLM module 30 includes an SLM 31 and receives the light emitted from the beam shaping optical system 22, modulates the input light, and emits it. The lens 23 is a lens that receives the light emitted from the SLM module 30 and that has passed through the processing optical path, and focuses it onto the workpiece (object to be processed) 50.

[0026] The configuration of the SLM module 30 will now be described. As shown in Figure 2, the SLM module 30 includes an SLM 31, an imaging optical system 32, a mirror 33, a lens 34, and a camera 35. The above components are positioned and arranged in the optical path of the light used for laser processing in the order of SLM 31, imaging optical system 32, mirror 33, lens 34, and camera 35.

[0027] SLM31 modulates and outputs the light input to SLM module 30 via beam shaping optical system 22. SLM31 receives hologram data D1 for realizing CGH from control device 40, realizes the hologram, and uses it for light modulation.

[0028] The imaging optical system 32 is an optical system that images the light output from the SLM 31 onto the lens 34 so that laser processing is performed on the workpiece 50. The mirror 33 is an optical system that splits the light output from the imaging optical system 32. One of the light split by the mirror 33 (for example, the light reflected by the mirror 33) is incident on the workpiece 50 via the processing optical path and the lens 23.

[0029] The other beam of light, split by the mirror 33 (for example, the light that passes through the mirror 33), enters the lens 34. The lens 34 is a lens that receives the light split by the mirror 33 and focuses it into the camera 35. The camera 35 is a device that images the light output from the lens 34, i.e., the light emitted from the SLM 31. For example, the camera 35 is an image sensor such as a CMOS (Complementary Metal Oxide Semiconductor) camera. The image captured by the camera 35 is the intensity distribution at the point where the light emitted from the SLM 31 is focused.

[0030] The image data D2 of the light emitted from the SLM31, captured by the camera 35, is input to the control device 40. This data D2 is used to correct the hologram data used in the SLM31.

[0031] Each component of the laser processing machine 20 may be the same as that of a conventional laser processing machine using an SLM. However, the laser processing machine 20 does not necessarily have to have the above configuration; it may also have a configuration that does not include any of the above components, or a configuration that includes components other than those listed above.

[0032] Next, the functions of the hologram data generation system 10 according to this embodiment will be described. As shown in Figure 1, the hologram data generation system 10 is configured to include an acquisition unit 11, a determination unit 12, and a generation unit 13.

[0033] The acquisition unit 11 is an acquisition means that acquires target information showing the intensity distribution of the emitted light, which is the target of the emitted light from the hologram. The target information is, for example, an image showing the intensity distribution at the point of focus of the emitted light. An example of target information is shown in Figure 3. Specifically, the target information includes information showing the light intensity I0(x,y) for each position (x,y) on a plane perpendicular to the direction of light propagation (z direction) at a predetermined position (z=0) in the direction of light propagation. This is the first image shown in Figure 3. In this embodiment, the stronger the light intensity, the whiter the color, and the weaker the light intensity, the blacker the color. The predetermined position (z=0) in the direction of light propagation is the position where the emitted light from the SLM 31 is focused, i.e., the processing position of the workpiece material 50. In the example of the first image shown in Figure 3, it is shown that light is irradiated at the positions of two points side by side, and no light is irradiated (or extremely weak light is irradiated) at other positions.

[0034] The target information is the light intensity I for each position (x,y) on a plane perpendicular to the direction of light propagation (z direction) at a predetermined position (z=L) that is different from the above. L The information may include (x,y) coordinates. This is the second image in Figure 3. If the position where the light emitted from the SLM31 is focused spans multiple positions in the direction of light propagation, the second image may be included. Note that the target information described above is just an example, and the target information may be any other information that shows the intensity distribution of the emitted light that is the target of the light emitted from the hologram.

[0035] The target information will depend on the type of laser processing to be performed on the workpiece material 50. Therefore, the user of the laser processing machine 20 generates the target information according to the processing content. The generation of the target information can be done in the same way as before.

[0036] Target information is transmitted from the control device 40 to the hologram data generation system 10 by, for example, the user of the laser processing machine 20. The acquisition unit 11 receives and acquires the transmitted target information. Note that the acquisition of target information by the acquisition unit 11 may be performed by methods other than those described above. The acquisition unit 11 outputs the acquired target information to the determination unit 12 and the generation unit 13.

[0037] Hologram data is generated such that when the hologram realized using this data is used and light modulation is performed by the SLM31, the intensity distribution of the emitted light matches the intensity distribution indicated by the target information. Hologram data is generated based on the target information according to a predetermined generation method, specifically a predetermined algorithm. However, if a uniform generation method, such as a specific algorithm, is used to generate the hologram, the distribution of the emitted light from the hologram may not be appropriate for the intended use.

[0038] In contrast, the hologram data generation system 10 according to this embodiment, as shown in Figure 4, automatically determines an algorithm (computational library) for generating hologram data according to the type of intensity distribution indicated by the target information (e.g., multi-point beam, non-diffraction beam, Laguerre-Gaussian mode, solid pattern), and generates hologram data. By generating hologram data in this way, the hologram used for light modulation by the SLM31 can be made appropriate.

[0039] The determination unit 12 is a determination means that determines a generation method to be used to generate hologram data according to the type of intensity distribution indicated by the target information acquired by the acquisition unit 11. The determination unit 12 may determine the type of intensity distribution from the intensity distribution indicated by the target information acquired by the acquisition unit 11, and determine a generation method to be used to generate hologram data according to the determined type. The type of intensity distribution may include at least one of discrete distributions, distributions in the direction of propagation of emitted light, and annular distributions.

[0040] The generation method used to generate hologram data is an algorithm that takes target information as input and outputs hologram data. Multiple algorithms are provided in advance, and the decision unit 12 selects a generation method from among these algorithms based on the target information to be used to generate hologram data. For example, the algorithms are pre-stored in the hologram data generation system 10 as a calculation library. The calculation library may be updated as needed to keep it up-to-date. The decision unit 12 may also determine a generation method other than those described above. For example, the decision unit 12 may determine a generation method as follows.

[0041] The determination unit 12 receives target information from the acquisition unit 11. The determination unit 12 determines the type of intensity distribution from the intensity distribution indicated by the input target information. In this embodiment, the types of intensity distributions are multi-point beam, non-diffraction beam, Laguerre-Gaussian mode, and solid pattern. The determination unit 12 determines which of these four types the intensity distribution corresponds to.

[0042] A multi-point beam is a type of beam in which, in the intensity distribution shown by target information, the positions of the emitted light (positions where the intensity is above a certain level, and so on) are discontinuous, and the intensity distribution of each continuous emitted light is a Gaussian distribution (Gaussian profile). In other words, a multi-point beam is a discrete distribution. For example, the intensity distribution shown in Figure 5(a) is a multi-point beam. A non-diffractive beam is a type of beam in which, in the intensity distribution shown by target information, the light propagates non-diffractically in the direction of propagation. In other words, a non-diffractive beam is a distribution in the direction of propagation of the emitted light.

[0043] Laguerre-Gaussian modes are a type of intensity distribution where the position of the emitted light is distributed in an annular (ring-shaped) pattern, as indicated by the target information. For example, the intensity distribution shown in Figure 5(b) is a Laguerre-Gaussian mode. Solid patterns are a type of intensity distribution that does not fall into any of the above categories. For example, the intensity distribution shown in Figure 5(c) is a solid pattern.

[0044] The determination unit 12 determines the type of intensity distribution, for example, as follows: The determination unit 12 binarizes the image of the intensity distribution at z=0 (the first image) using a preset threshold and detects the contours of the emitted light (for example, the dashed lines in each intensity distribution in Figure 5). The determination unit 12 determines whether there are two or more groups of consecutive emitted light indicated by the detected contours. If the number of groups is two or more, the determination unit 12 determines that it is a branched pattern, and if the number of groups is not two or more, it determines that it is not a branched pattern. For example, the intensity distribution shown in Figure 5(a) is determined to be a branched pattern, and the intensity distributions shown in Figures 5(b) and (c) are determined not to be branched patterns.

[0045] If the intensity distribution is determined to be a branching pattern, the determination unit 12 determines whether the intensity distribution of a group of consecutive individual emitted light beams is a Gaussian profile. If the determination unit 12 determines that the intensity distribution of a group of consecutive individual emitted light beams is a Gaussian profile, the determination unit 12 determines that the type of intensity distribution indicated by the target information is a multi-point beam.

[0046] If the intensity distribution is determined not to be a branching pattern, or if the intensity distribution of a group of consecutive emitted light beams is determined not to be a Gaussian profile, the determination unit 12 then determines whether the target information includes an image of the intensity distribution at z=L (the second image) (i.e., whether it is an intensity distribution at multiple positions in the direction of propagation of the emitted light). If it determines that the second image is included, the determination unit 12 determines that the type of intensity distribution indicated by the target information is a non-diffraction beam.

[0047] If the determination unit 12 determines that the second image is not included, it determines whether the position of the emitted light in the intensity distribution is ring-shaped or not (whether the intensity distribution is a ring pattern or not). This determination is made, for example, using the binarized image described above. If the determination unit 12 determines that the position of the emitted light in the intensity distribution is ring-shaped, it determines that the type of intensity distribution indicated by the target information is a Laguerre-Gaussian mode. If the determination unit 12 determines that the position of the emitted light in the intensity distribution is not ring-shaped, it determines that the type of intensity distribution indicated by the target information is a solid pattern. Each of the above determinations regarding the intensity distribution (image) can be made using conventional image processing techniques.

[0048] The determination unit 12 stores the type of intensity distribution and the algorithm used to generate the hologram data in association with each other. The algorithm is capable of generating hologram data suitable for the corresponding type of intensity distribution. Hologram data suitable for the type of intensity distribution is one in which the intensity distribution of the emitted light from the realized hologram is an intensity distribution that more accurately represents the target information.

[0049] For example, the algorithm shown in Hidetomo Takahashi et al., “Holographic femtosecond laser processing using optimal-rotation-angle method with compensation of spatial frequency response of liquid crystal spatial light modulator”, Appl. Opt. 46, 5917-5923 (2007) is applicable to multi-point beams. The algorithm shown in Zhongsheng Zhai et al., “Tunable Axicons Generated by Spatial Light Modulator with High-Level Phase Computer-Generated Holograms”, Appl. Sci. 10, 5127 (2020) is applicable to non-diffraction beams. The algorithm shown in Japanese Patent Publication No. 2008-134450 is applicable to Laguerre-Gaussian modes. The solid patterns correspond to the algorithms shown on page 140 onwards of Fred M. Dickey and Scott C. Holswade, “Laser Beam Shaping Theory and Techniques”, CRC Press, (2000).

[0050] The determination unit 12 determines (selects) an algorithm associated with the determined intensity distribution type as the algorithm to be used to generate hologram data. The determination unit 12 notifies the generation unit 13 of the determined algorithm.

[0051] Furthermore, the determination of the intensity distribution type by the determination unit 12 does not necessarily have to be performed as described above, and may be done by any method. Also, the determined intensity distribution type does not have to be one of those described above; any type is acceptable as long as it makes the hologram used in SLM31 appropriate. In addition, algorithms other than those described above may be used for each type.

[0052] The generation unit 13 is a generation means that generates hologram data from target information acquired by the acquisition unit 11 according to the generation method determined by the determination unit 12. The generation unit 13 receives target information from the acquisition unit 11. The generation unit 13 receives notification from the determination unit 12 of the algorithm to be used to generate the hologram data.

[0053] The generation unit 13 reads the algorithm (computation library) notified by the determination unit 12 and generates hologram data from the target information input from the acquisition unit 11 using the algorithm. As described above, the generation of hologram data is performed so that the intensity distribution of the emitted light from the hologram realized by the hologram data matches the intensity distribution of the emitted light indicated by the target information. The generation of hologram data using the algorithm itself can be performed in the same way as in the conventional method.

[0054] The generation unit 13 outputs the generated hologram data. For example, the generation unit 13 transmits the generated hologram data to the control device 40, which is the source of the target information. The control device 40 receives the hologram data. The hologram data is input from the control device 40 to the SLM 31 included in the laser processing machine 20, and is used in the SLM 31 to realize a hologram for light modulation.

[0055] The generation unit 13 may use information other than target information to generate hologram data. For example, the image data D2 (measurement data from the camera 35) of the light emitted from the SLM 31 captured by the camera 35 may be used to generate hologram data. This image data D2 is transmitted from the control device 40 to the hologram data generation system 10. The generation unit 13 receives and acquires the image data D2.

[0056] The generation unit 13 uses the image data D2 to correct (modify) the hologram data. For example, in the case of target information to make the intensity of each of the multi-point beams shown in Figure 5(a) uniform, the intensity may be affected by aging of the laser light source or optical elements, etc., which may cause a bias to occur on one side. Also, environmental factors such as humidity and temperature affect the light emitted from the SLM 31. In this case, the measurement data from the camera 35 is fed back to the hologram data generation system 10, and corrections are made, for example, by weakening the strong intensity parts and strengthening the weak intensity parts, hologram data suitable for the target information can be generated. In addition, in this case, for example, in the laser processing machine 20 shown in Figure 2, an optical or mechanical shutter may be provided in the optical path between the mirror 33 and the lens 34, and the shutter may be closed until the final hologram data is generated so that light is not irradiated onto the workpiece material 50.

[0057] Furthermore, for example, the processing state of the workpiece material 50 may be monitored using optical interferometry as described in F. Mezzapesa et al., “High-resolution monitoring of the hole depth during ultrafast laser ablation drilling by diode laser self-mixing interferometry”, Opt. Lett. 36, 822-824 (2011), and hologram data may be generated based on the measurement information. In addition, the generation unit 13 may also use information other than the above (for example, information regarding the hardware of the laser processing machine 20) to generate hologram data. The above describes the functions of the hologram data generation system 10 according to this embodiment.

[0058] Next, using the flowcharts in Figures 6 and 7, we will explain the hologram data generation method, which is a process (a method of operation performed by the hologram data generation system 10) executed by the hologram data generation system 10 according to this embodiment.

[0059] As shown in Figure 6, in this process, first, target information is acquired by the acquisition unit 11 (S01, acquisition step). Target information is acquired, for example, by receiving target information transmitted from the control device 40. Subsequently, the determination unit 12 determines the type of intensity distribution from the intensity distribution indicated by the target information (S02, determination step).

[0060] The flowchart in Figure 7 illustrates the process for determining the type of intensity distribution. In this process, first, it is determined whether the intensity distribution indicated by the target information is a branched pattern (S21). If it is determined that the intensity distribution is a branched pattern (YES in S21), then it is determined whether the individual branched intensity distributions are Gaussian profiles (S22). If it is determined that the individual branched intensity distributions are Gaussian profiles (YES in S22), then the type of intensity distribution is determined to be a multi-point beam.

[0061] If it is determined that the individual branched intensity distributions are not Gaussian profiles (NO in S22), or if it is determined in S21 that the intensity distribution is not a branched pattern (NO in S21), then it is determined whether the target information includes an image of the intensity distribution at z=L (second image) (S23, S25). If it is determined that the target information includes an image of the intensity distribution at z=L (second image) (YES in S23, YES in S25), then the type of intensity distribution is determined to be a non-diffraction beam.

[0062] If it is determined that the target information does not include an image of the intensity distribution at z=L (the second image) (NO in S23, NO in S25), then it is determined whether the position of the emitted light of the intensity distribution is ring-shaped (whether the intensity distribution is a ring pattern) (S24, S26). If it is determined that the position of the emitted light of the intensity distribution is ring-shaped (the intensity distribution is a ring pattern) (YES in S24, YES in S26), then the type of intensity distribution is determined to be a Laguerre Gaussian mode. If it is determined that the position of the emitted light of the intensity distribution is not ring-shaped (the intensity distribution is not a ring pattern) (NO in S24, NO in S26), then the type of intensity distribution is determined to be a solid pattern. The above is the process for determining the type of intensity distribution.

[0063] Next, as shown in Figure 6, the determination unit 12 determines an algorithm, which is a generation method used to generate hologram data, according to the type of intensity distribution (S03, determination step). Subsequently, the generation unit 13 generates hologram data from the target information acquired by the acquisition unit 11 using the algorithm determined by the determination unit 12 (S04, generation step). The generated hologram data is output from the generation unit 13 (S05). The generated hologram data is transmitted from the generation unit 13 to the control device 40, for example, and used to realize a hologram in the SLM 31 included in the laser processing machine 20. This is the process executed in the hologram data generation system 10 according to this embodiment.

[0064] In this embodiment, hologram data is generated by an appropriate generation method according to the type of intensity distribution of the emitted light, which is the target of the emitted light from the hologram. Therefore, according to this embodiment, the hologram used in the SLM31 can be made appropriate.

[0065] Furthermore, as in the embodiment described above, the hologram data generation system 10 may determine the type of intensity distribution from the intensity distribution indicated by the target information, and determine the generation method to be used for generating the hologram data according to the determined type. With this configuration, the generation method can be determined appropriately and reliably. As a result, the hologram used in the SLM31 can be reliably made appropriate. However, it is not always necessary for the hologram data generation system 10 to determine the type of intensity distribution. For example, information indicating the type of intensity distribution indicated by the target information may be acquired along with the target information, and the generation method may be determined using that information.

[0066] Furthermore, as described above, the type of intensity distribution may include at least one of discrete distributions, distributions in the direction of light propagation, and annular distributions. This configuration allows for an appropriate type of intensity distribution to determine the generation method. As a result, it is possible to reliably produce an appropriate hologram in the SLM31.

[0067] In the embodiments described above, the algorithm used to generate hologram data was determined according to the type of intensity distribution. However, the algorithm may also be determined according to the data format of the target information to be acquired. For example, if the target information to be acquired is different from that described above and is 6-dimensional data of (x,y,z,a,px,py), an algorithm appropriate to that case may be used. Of the above 6-dimensional data, (x,y,z) are spatial coordinates (positions) for showing the intensity distribution. z is the coordinate in the direction of light propagation, and x and y are the coordinates on a plane perpendicular to that direction. a is a value indicating the brightness (signal intensity) at the position (x,y,z). px and py are values ​​indicating the polarization in the x and y directions at the position (x,y,z).

[0068] If the target information is the six-dimensional data described above, for example, the GS (Gerchberg and Saxton) method shown in Optik 35, 235-346 (1972) can be used as the algorithm for generating hologram data. By determining the algorithm according to the data format of the target information in this way, the hologram used in SLM31 can be made appropriate. [Explanation of symbols]

[0069] 10...Hologram data generation system, 11...Acquisition unit, 12...Determination unit, 13...Generation unit, 20...Laser processing machine, 21...Laser light source, 22...Beam shaping optical system, 23...Lens, 30...SLM module, 31...SLM, 32...Imaging optical system, 33...Mirror, 34...Lens, 35...Camera, 40...Control device, 50...Workpiece material.

Claims

1. A hologram data generation system for generating hologram data to realize a hologram used for modulating light in a spatial light modulator, A means for acquiring target information that shows the intensity distribution of the emitted light, which is the target of the emitted light from the hologram, A determination means that determines a generation method to be used for generating hologram data from a plurality of pre-prepared, mutually different generation methods, according to the type of intensity distribution indicated by the target information acquired by the acquisition means, A generation means that generates hologram data from target information acquired by the acquisition means according to the generation method determined by the determination means, A hologram data generation system equipped with the following features.

2. The hologram data generation system according to claim 1, wherein the determination means determines the type of intensity distribution from the intensity distribution indicated by the target information acquired by the acquisition means, and determines a generation method to be used for generating hologram data according to the determined type.

3. The hologram data generation system according to claim 1 or 2, wherein the type of intensity distribution includes at least one of a discrete distribution, a distribution in the direction of propagation of emitted light, and an annular distribution.

4. A method for generating hologram data, which is a method for operating a hologram data generation system that generates hologram data for realizing a hologram used for modulating light in a spatial light modulator, An acquisition step to obtain target information showing the intensity distribution of the emitted light, which is the target of the emitted light from the hologram, A decision step in which, according to the type of intensity distribution indicated by the target information acquired in the acquisition step, a generation method to be used for generating hologram data is determined from a plurality of pre-prepared, mutually different generation methods, A generation step in which data for a hologram is generated from target information acquired in the acquisition step, using the generation method determined in the determination step, A method for generating data for holograms, including the data itself.

Images