Optical instrument, light shaping method, and processing method

Abstract

An optical instrument (10) comprises a diffractive optical element (100) having a first region and a second region adjacent to the first region, and an optical system (200) for simultaneously emitting light to the first region and the second region, wherein the difference between the phase of light that has passed through the first region (101) and the phase of light that has passed through the second region (102) is (n1-5 / 10)π[rad] or more and (n1+5 / 10)π[rad] or less, where n1 is an arbitrarily defined odd number.

Description

Optical equipment, light shaping method, and processing method

[0001] The present invention relates to an optical instrument, a light shaping method, and a processing method.

[0002] In recent years, various laser processing devices have been developed for performing laser processing such as laser welding and laser cutting. Laser processing devices are equipped with a beam shaping device. The beam shaping device shapes light (beam) emitted from a light source such as a laser oscillator, for example, using a diffractive optical element. The beam shaping device irradiates an object with light (beam) having a desired pattern.

[0003] Patent Document 1 describes an example of a diffractive optical element for a beam shaping device. This diffractive optical element includes a first region having a diffraction grating and a rectangular shape, and a second region surrounding the first region and not having a diffraction grating. Patent Document 1 describes sliding the diffractive optical element so that a beam spot overlaps the first region of the diffractive optical element, and sliding the beam spot so that it shifts from the first region of the diffractive optical element and overlaps the second region of the diffractive optical element.

[0004] Patent No. 6369454

[0005] In laser processing, a laser beam combining a ring beam and a central beam is sometimes desired. For this reason, technologies for adjusting the intensity ratio between the ring beam and the central beam have been investigated in recent years, and devices have been provided that can freely adjust the intensity ratio between the ring beam and the central beam by injecting lasers into a double-layered optical fiber. However, the aforementioned devices are restricted by the thickness of the optical fiber, limiting the ring diameter and central diameter. In contrast, if a similar shape is formed using a diffractive optical element, the degree of freedom in shape is greatly improved, but the ratio cannot be adjusted. One example of the objectives of the present invention is to provide an optical device that can easily adjust the intensity ratio between the ring beam and the central beam while using a diffractive optical element.

[0006] According to the present invention, there are provided the following optical device, light shaping method, and processing method.

[0007] [1] An optical device comprising: a diffractive optical element having a first region and a second region adjacent to the first region; and an optical system that simultaneously irradiates the first region and the second region with light, wherein a difference between the phase of the light that has passed through the first region and the phase of the light that has passed through the second region is equal to or greater than (n1-5 / 10)π [rad] and equal to or less than (n1+5 / 10)π [rad], where n1 is an arbitrary odd number. [2] The optical device according to [1], wherein the optical system is capable of varying the diameter of the incident light. [3] The optical device according to [1] or [2], wherein the first region is circular. [4] The optical device according to [3], wherein, when the intensity of the light at the center of the light is 100, the intensity of the light at the edge of the first region is equal to or greater than 4 and equal to 89. [5] The optical device according to [3] or [4], wherein the diffractive optical element has the second region that is ring-shaped and concentric with the first region. [6] The optical device according to [5], wherein, when the intensity of the light at the center of the light is 100, the intensity of the light at the edge of the first region is equal to or greater than 4 and less than 100, and the intensity of the light at the outer edge of the second region is greater than 0 and equal to or less than 89. [7] The optical device according to [5] or [6], wherein the diffractive optical element further has a ring-shaped third region adjacent to the second region, located outside the second region, and concentric with the first region, the optical system irradiates the first region, the second region, and the third region with light simultaneously, and a difference in phase between the light that has passed through the second region and the light that has passed through the third region is equal to or greater than (n2 - 5 / 10)π [rad] and equal to or less than (n2 + 5 / 10)π [rad], where n2 is any odd number. [8] The optical device according to [7], wherein, when the intensity of the light at the center of the light is 100, the intensity of the light at the edge of the first region is 4 or more and less than 100, and the intensity of the light at the outer edges of the second region and the third region is more than 0 and 89 or less. [9] The optical device according to [1] or [2], wherein the first region is polygonal.

[10] An optical device comprising: a lens having a first lens portion and a second lens portion having a light refraction angle different from that of the first lens portion; and an optical system that irradiates light onto the first lens portion and the second lens portion simultaneously.

[11] The optical device according to

[10] , wherein the optical system is capable of varying the diameter of incident light.

[12] A light shaping method for shaping light using the optical device according to any one of [1] to

[11] .

[13] A processing method for processing an object using light shaped by the light shaping method according to

[12] .

[0008] According to the above-described aspects of the present invention, it is possible to provide an optical device that can easily adjust the intensity ratio between the ring light and the central light.

[0009] 12 is a diagram showing a first example of the configuration of an optical device. FIG. 13 is a diagram showing an example of the structure of an optical device when the diffractive optical element is a reflective diffractive optical element. FIG. 14 is a plan view showing a first example of the structure of a diffractive optical element. FIG. 15 is a diagram showing the phase of light after passing through each region between A-A' in FIG. 3. FIG. 16 is a diagram showing a simulation result of diffracted light formed when light is incident on the diffractive optical element shown in FIG. 3. FIG. 17 is a diagram showing the simulation result of diffracted light formed when light of each diameter is incident on the diffractive optical element shown in FIG. 3. FIG. 18 is a graph showing the light intensity of each ring light and central light of the diffracted light shown in FIG. 6. FIG. 19 is a plan view showing a second example of the structure of a diffractive optical element. FIG. 19 is a diagram showing the phase of light after passing through each region between B-B' in FIG. 8. FIG. 20 is a diagram showing the simulation result of diffracted light formed when light of each diameter is incident on the diffractive optical element shown in FIG. 20. FIG. 21 is a graph showing the light intensity of each ring light and central light of the diffracted light shown in FIG. 14. FIG. 22 is a diagram showing the simulation results of diffracted light formed when light of each diameter is incident on the diffractive optical element shown in FIG. 12 (with the ratio shifted). FIG. 23 is a graph showing the light intensity of each ring light and central light of the diffracted light shown in FIG. 16. FIG. 24 is a plan view showing a fourth example of the structure of a diffractive optical element. FIG. 25 is a diagram showing the phase of light after passing through each region between D-D' in FIG. 18. FIG. 26 is a diagram showing the simulation results of diffracted light formed when light of each diameter is incident on the diffractive optical element shown in FIG. 18. FIG. 26 is a graph showing the light intensity of each ring light and central light of the diffracted light shown in FIG. 20. FIG. 27 is a plan view showing a fifth example of the structure of a diffractive optical element. FIG. 28 is a diagram showing the phase of light after passing through each region between D-D' in FIG. 22. FIG. 29 is a diagram showing the simulation results of diffracted light formed when light of each diameter is incident on the diffractive optical element shown in FIG. 22. FIG. 29 is a graph showing the light intensity of each ring light and central light of the diffracted light shown in FIG. 24. FIG. 29 is a first diagram for explaining a first example of the details of the optical system.37 is a second diagram for explaining a first example of the details of the optical system. 38 is a third diagram for explaining a first example of the details of the optical system. 39 is a first diagram for explaining a second example of the details of the optical system. 40 is a third diagram for explaining a second example of the details of the optical system. 41 is a diagram showing a simulation result of diffracted light formed when d1 of the diffractive optical element shown in FIG. 8 is adjusted and light is incident thereon. 42 is a graph showing the light intensity of each of the ring light and central light of the diffracted light shown in FIG. 32. 43 is a diagram showing a simulation result of diffracted light formed when light is incident thereon when the phase difference of the diffractive optical element shown in FIG. 3 is adjusted. 44 is a graph showing the light intensity of each of the ring light and central light of the diffracted light shown in FIG. 34. 45 is a diagram showing a second example of the configuration of an optical device. 46 is a plan view of a lens. 47 is a cross-sectional view taken along the E-E' cross section of FIG. 46. 48 is a diagram showing a simulation result of diffracted light formed when light of each diameter is incident on the lens shown in FIG. 38. 49 is a graph showing the light intensity of each of the ring light and central light of the diffracted light shown in FIG. 49. 49 is a diagram showing a simulation result of diffracted light formed when light of each diameter is incident on the lens shown in FIG. 38. 49 is a graph showing the light intensity of each of the ring light and central light of the diffracted light shown in FIG. 41. 41 is a diagram showing a modified example of the lens. 42 is a cross-sectional view taken along the E-E' cross section of FIG. 46. 42 is a diagram showing a simulation result of diffracted light formed when light of each diameter is incident on the lens shown in FIG. 38. 43 is a graph showing the light Fig. 44 is a diagram showing the simulation results of diffracted light formed when light of each diameter is incident on the lens shown in Fig. 43. Fig. 45 is a graph showing the light intensity of the ring light and the central light of the diffracted light shown in Fig. 44. Fig. 46 is a diagram showing diffracted light in an example.

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, like components are denoted by like reference numerals, and the description thereof will be omitted as appropriate.

[0011] 1 is a diagram showing an example of the configuration of an optical device 10 according to this embodiment. The optical device 10 includes a diffractive optical element 100, an optical system 200, a condenser lens 300, and a housing 400. The optical device 10 is used together with a light source 30 and an optical fiber 40, for example.

[0012] The light source 30 is a device that generates light, such as a laser oscillator that generates laser light. The light is, for example, light in the near-infrared wavelength range (e.g., light with a wavelength of 1064 nm). However, the light may be light in other wavelength ranges, light in a wavelength range longer than the near-infrared wavelength range, visible light, or light in the ultraviolet wavelength range. The light generated by the light source 30 is sent to the optical device 10 via an optical fiber 40.

[0013] The optical device 10 shapes light sent from the light source 30. The optical device 10 has a configuration in which a housing 400 houses a diffractive optical element 100, an optical system 200, and a condenser lens 300. The light sent to the optical device 10 is first incident on the optical system 200. The optical system 200 then shapes the incident light, and the light is then incident on the diffractive optical element 100.

[0014] The diffractive optical element 100 has a structure for forming diffracted light, and shapes at least a portion of the incident light into a ring beam. The portion of the light that is not shaped into a ring beam remains as a central beam. The intensity ratio between this central beam and the ring beam varies depending on the diameter of the light incident on the diffractive optical element 100. In the following description, the diameter of the light is measured from the distribution curve of the light intensity, and when the intensity at the center of the light is 1, the light intensity from the center of the light is 1 / e ２ is twice the distance to the point where

[0015] Furthermore, it is preferable that the optical system 200 can change the diameter of the light incident on the diffractive optical element 100. In this case, the optical system 200 can adjust the intensity ratio between the ring light and the central light of the diffracted light formed by the diffractive optical element 100 by adjusting the diameter of the light incident on the diffractive optical element 100. The method by which the optical system 200 adjusts the shape and size of the light will be described later.

[0016] The diffractive optical element 100 then causes the formed diffracted light to be incident on the condenser lens 300. The condenser lens 300 then focuses the incident diffracted light and irradiates it onto the object 20. In this manner, the optical device 10 processes the object 20 by irradiating it with the diffracted light. As an example, the optical device 10 is used for laser processing, such as laser welding or laser cutting.

[0017] In FIG. 1, the diffractive optical element 100 is a transmissive diffractive optical element, but the diffractive optical element 100 is not limited to the transmissive type.

[0018] FIG. 2 is a diagram showing an example of the structure of the optical device 10 when the diffractive optical element 100 is a reflective diffractive optical element.

[0019] When the diffractive optical element 100 is a transmissive type, the structure for forming diffracted light is formed on the first surface 110 on the focusing lens 300 side, the second surface 120 on the optical system 200 side, or on both surfaces thereof; when the diffractive optical element 100 is a reflective type, the structure for forming diffracted light is formed on the second surface 120 on the optical system 200 side.

[0020] Furthermore, if the diffractive optical element 100 is a transmissive type, the diffractive optical element 100 is formed using, for example, a quartz substrate, and if the diffractive optical element 100 is a reflective type, the diffractive optical element 100 is formed using, for example, a metal substrate.

[0021] Next, a detailed description will be given of the structure for forming diffracted light that the diffractive optical element 100 has. In the following description, unless otherwise specified, the diffractive optical element 100 is assumed to be a transmissive type.

[0022] FIG. 3 is a plan view showing a first example of the structure of the diffractive optical element 100. As shown in FIG. 3, the first surface 110 has a first region 101 and a second region 102. In the first example shown in FIG. 3, the first region 101 is circular with an outer diameter d1. The second region 102 is formed adjacent to the periphery of the first region 101. The first region 101 and the second region 102 are formed so that a phase difference occurs between the phase of light passing through the first region 101 and the phase of light passing through the second region 102. The phase difference is preferably not less than (n-5 / 10)πrad and not more than (n+5 / 10)πrad, more preferably not less than (n-3 / 10)πrad and not more than (n+3 / 10)πrad, and even more preferably not less than (n-1 / 10)πrad and not more than (n+1 / 10)πrad. Here, n is any odd number.

[0023] 4 is a diagram showing the phase of light after passing through each region between A and A' when the diffractive optical element 100 shown in FIG. 3 is formed with a phase difference of π rad. The point of 0 on the horizontal axis corresponds to the center point O in FIG. 3. The vertical axis shows the phase of light based on the phase of light that has passed through the second region 102.

[0024] Light is incident on the diffractive optical element 100 from the optical system 200 at a center point O (see FIG. 3 ). The light is then incident simultaneously on the first region 101 and the second region 102. Both light passing through the first region 101 and light passing through the second region 102 are generated. The light passing through the first region 101 and the light passing through the second region 102 form diffracted light.

[0025] 5 shows the results of a simulation of the intensity of diffracted light formed when the diffractive optical element 100 shown in FIG. 3 is formed under the conditions of a phase difference of π rad and d1 of 6.4 mm and light having a diameter of φ of 10.0 mm is incident on the element, assuming a combination with a focusing lens of F=+1 m. As shown in FIG. 5, the diffracted light includes a ring beam and a central beam.

[0026] Furthermore, in the diffractive optical element 100 according to this embodiment, the ratio of the area irradiated with light on the first region 101 to the area irradiated with light on the second region 102 can be changed according to the diameter of the incident light. Therefore, the diffractive optical element 100 according to this embodiment can adjust the intensity ratio between the ring light and the central light of the diffracted light by adjusting the diameter of the incident light.

[0027] 6 shows the results of a simulation of the intensity of diffracted light formed when the diffractive optical element 100 shown in FIG. 3 is formed under the conditions of a phase difference of π rad and d1 of 6.4 mm, and light beams with diameters of φ of 8.0 mm, 9.0 mm, 10.0 mm, and 16.0 mm are incident thereon, assuming a combination with a focusing lens with F=+1 m. As shown in FIG. 6, the intensity ratio of the central light beam increases as the diameter of the incident light beam increases. In this way, the diffractive optical element 100 according to this embodiment can adjust the intensity ratio of the ring light and the central light beam according to the diameter of the incident light beam.

[0028] Fig. 7 is a graph showing the light intensity of the ring light and the central light of the diffracted light for each diameter φ shown in Fig. 6. In Fig. 7, the horizontal axis represents the diameter φ, and the vertical axis represents the light intensity. The light intensity on the vertical axis is a value normalized by the total energy of the light. As shown in Fig. 7, as the diameter φ increases, the intensity ratio of the central light to the ring light increases, and the intensity ratio of the ring light and the central light can be adjusted depending on the diameter of the incident light.

[0029] From the viewpoint of making the diffracted light have a ring-shaped light component, in the diffractive optical element 100 shown in Fig. 3, when the light intensity at the center of the incident light is 100, the light intensity at the edge of the first region 101 is preferably 4 or more and 89 or less. Furthermore, when the optical system 200 is capable of varying the diameter of the light incident on the diffractive optical element 100, it is preferable that the light diameter be variable within a range that includes at least a part or all of the light diameter within which the light intensity of each region falls within the above-mentioned range.

[0030] In this way, the optical device 10 according to this embodiment can form diffracted light having a ring beam and a central beam by having the optical system 200 simultaneously irradiate the first region 101 and the second region 102 of the diffractive optical element 100 with light. Furthermore, the intensity ratio between the ring beam and the central beam can be adjusted by adjusting the diameter of the light incident on the optical system 200. Other examples of the diffractive optical element 100 will be described below.

[0031] 8 is a plan view showing a second example of the structure of the diffractive optical element 100. In this second example, the first region 101 is circular and has an outer diameter d1. The second region 102 is in contact with the first region 101 and has a ring shape with an outer diameter d2 that is concentric with the first region 101. A peripheral region 105 is formed around the second region 102. Each region is formed so that a phase difference occurs between the phase of light that has passed through the first region 101 and the phase of light that has passed through the second region 102, and between the phase of light that has passed through the second region 102 and the phase of light that has passed through the peripheral region 105. Each phase difference is preferably (n-5 / 10)πrad or more and (n+5 / 10)πrad or less, more preferably (n-3 / 10)πrad or more and (n+3 / 10)πrad or less, and even more preferably (n-1 / 10)πrad or more and (n+1 / 10)πrad or less, where n is any odd number.

[0032] 9 is a diagram showing the phase of light after passing through each region between B and B′ when the diffractive optical element 100 shown in FIG. 8 is formed such that the phase difference between the phase of light passing through the first region 101 and the phase of light passing through the second region 102, and the phase of light passing through the second region 102 and the phase of light passing through the peripheral region 105 are set to π rad, and the phase of light passing through the first region 101 and the phase of light passing through the peripheral region 105 are set to the same phase. The point of 0 on the horizontal axis corresponds to the center point O in FIG. 8. The vertical axis indicates the phase of light based on the phase of light passing through the first region 101 and the phase of light passing through the peripheral region 105.

[0033] Figure 10 shows the results of a simulation assuming a combination of the diffractive optical element 100 shown in Figure 8 with a focusing lens of F = +1 m, and the intensity of diffracted light formed when light having a diameter φ of 8.0 mm, 10.0 mm, 11.0 mm, or 16.0 mm is incident, with the phase difference between the phase of light that has passed through the first region 101 and the phase of light that has passed through the second region 102, and between the phase of light that has passed through the second region 102 and the phase of light that has passed through the peripheral region 105 being πrad, and the phase of light that has passed through the first region 101 and the phase of light that has passed through the peripheral region 105 being the same.

[0034] Fig. 11 is a graph showing the light intensity of the ring light and the central light of the diffracted light at each diameter φ shown in Fig. 10. In Fig. 11, the horizontal axis represents the diameter φ, and the vertical axis represents the light intensity. Note that the light intensity on the vertical axis is a value normalized by the total energy of the light. As shown in Fig. 11, as the diameter φ increases, the intensity ratio of the central light to the ring light increases. In the diffractive optical element 100 of the second example, the intensity ratio of the ring light to the central light can also be adjusted according to the diameter of the incident light.

[0035] From the viewpoint of causing the diffracted light to contain a ring-shaped light component, in the diffractive optical element 100 shown in Fig. 8, when the light intensity at the center of the incident light is 100, the light intensity at the edge of the first region 101 is preferably 4 or more and less than 100. Furthermore, the light intensity at the outer edge of the second region 102 is preferably more than 0 and 89 or less. Furthermore, when the optical system 200 is capable of varying the diameter of the light incident on the diffractive optical element 100, it is preferable that the light diameter be variable within a range that includes at least a part or all of the light diameters in which the light intensity of each region falls within the above-mentioned range.

[0036] 12 is a plan view showing a third example of the structure of the diffractive optical element 100. In the third example, the first region 101 is circular and has an outer diameter d1. The second region 102 is in contact with the first region 101 and is ring-shaped and has an outer diameter d2 that is concentric with the first region 101. A ring-shaped third region 103 having an outer diameter d3 and that is in contact with the second region 102 and concentric with the first region 101 is formed around the second region 102. A peripheral region 105 is formed around the third region 103. Each region is formed so that a phase difference occurs between the phase of light that has passed through the first region 101 and the phase of light that has passed through the second region 102, between the phase of light that has passed through the second region 102 and the phase of light that has passed through the third region 103, and between the phase of light that has passed through the third region 103 and the phase of light that has passed through the peripheral region 105. Each phase difference is preferably (n-5 / 10)πrad or more and (n+5 / 10)πrad or less, more preferably (n-3 / 10)πrad or more and (n+3 / 10)πrad or less, and even more preferably (n-1 / 10)πrad or more and (n+1 / 10)πrad or less, where n is any odd number.

[0037] 13 is a diagram showing the phase of light after passing through each region between C and C′ when the diffractive optical element 100 shown in FIG. 12 is configured such that the light passing through the first region 101 and the light passing through the third region 103 are in phase, the light passing through the second region 102 and the light passing through the peripheral region 105 are in phase, and the phase difference between the light passing through the first region 101 and the light passing through the second region 102 is π rad. The point of 0 on the horizontal axis corresponds to the center point O in FIG. 12. The vertical axis shows the phase of light based on the phase of the light passing through the second region 102 and the phase of the light passing through the peripheral region 105.

[0038] Figure 14 shows the results of a simulation assuming a combination of the diffractive optical element 100 shown in Figure 12 with a focusing lens of F = +1 m, where the light passing through the first region 101 and the light passing through the third region 103 are in phase, the light passing through the second region 102 and the light passing through the peripheral region 105 are in phase, the phase difference between the light passing through the first region 101 and the light passing through the second region 102 is πrad, and d1: 6.0 mm, d2: 10.0 mm, d3: 15.0 mm, and light with diameters φ: 6.0 mm, 10.0 mm, 14.0 mm, and 20.0 mm is incident.

[0039] Fig. 15 is a graph showing the light intensity of each ring beam and central beam of diffracted light for each diameter φ shown in Fig. 14. In Fig. 15, the horizontal axis represents the diameter φ, and the vertical axis represents the light intensity. Note that the light intensity on the vertical axis is a value normalized by the total energy of the light. As shown in Fig. 15, as the diameter φ increases, the intensity ratio of the central beam to the ring beam increases. In the diffractive optical element 100 of the third example, the intensity ratio of the ring beam to the central beam can also be adjusted according to the diameter of the incident light.

[0040] In the third example, by adjusting the ratio of d1, d2, and d3, it is possible to make the change in the intensity ratio between the ring light and the central light depending on the diameter of the incident light more noticeable.

[0041] Figure 16 shows the results of a simulation of the intensity of diffracted light formed when the diffractive optical element 100 shown in Figure 12 is formed under the conditions of phase difference: π rad, d1: 3.0 mm, d2: 10.0 mm, and d3: 15.0 mm, and light with diameters φ: 3.0 mm, 4.0 mm, 4.8 mm, and 16.0 mm is incident, assuming a combination with a focusing lens of F = +1 m.

[0042] 17 is a graph showing the light intensity of the ring light and the central light of the diffracted light at each diameter φ shown in FIG. 16. In FIG. 17, the horizontal axis represents the diameter φ, and the vertical axis represents the light intensity. Note that the light intensity on the vertical axis is a value normalized by the total energy of the light. As shown in FIG. 17, when d1 is set to 3.0 mm, the ratio of d1, d2, and d3 is disrupted, and the change in the intensity ratio of the ring light and the central light depending on the diameter of the incident light becomes more noticeable compared to FIG. 15.

[0043] 12 , when the light intensity at the center of the incident light is taken as 100, the light intensity at the edge of the first region 101 is preferably 4 or more and less than 100. Furthermore, the light intensity at the outer edges of the second region 102 and the third region 103 is preferably more than 0 and 89 or less. Furthermore, when the optical system 200 is capable of varying the diameter of the light incident on the diffractive optical element 100, it is preferable that the light diameter be variable within a range that includes at least a part or all of the light diameter within which the light intensity of each region falls within the above-mentioned range.

[0044] In the first to third examples, the first region 101 is formed in a circular shape, but the first region 101 is not limited to a circular shape and may be formed in a polygonal shape.

[0045] 18 is a plan view showing a fourth example of the structure of the diffractive optical element 100. In this fourth example, the first region 101 has an equilateral triangular shape with sides d4. Each region is formed so that a phase difference occurs between the phase of light passing through the first region 101 and the phase of light passing through the second region 102. The phase difference is preferably (n-5 / 10)πrad or more and (n+5 / 10)πrad or less, more preferably (n-3 / 10)πrad or more and (n+3 / 10)πrad or less, and even more preferably (n-1 / 10)πrad or more and (n+1 / 10)πrad or less. Here, n is any odd number.

[0046] Fig. 19 is a diagram showing the phase of light after passing through each region between D and D' when the diffractive optical element 100 shown in Fig. 18 is formed with a phase difference of π rad. The point of 0 on the horizontal axis corresponds to the center point O in Fig. 16. The vertical axis shows the phase of light based on the phase of light that has passed through the second region 102.

[0047] Figure 20 shows the results of a simulation of the intensity of diffracted light formed when the diffractive optical element 100 shown in Figure 18 is formed under the conditions of a phase difference of πrad and d4: 6.4 mm, and when light with diameters φ: 6.0 mm, 7.0 mm, 8.0 mm, and 12.0 mm is incident on the element, assuming a combination with a focusing lens of F = +1 m.

[0048] Fig. 21 is a graph showing the light intensity of each ring beam and central beam of diffracted light for each diameter φ shown in Fig. 20. In Fig. 21, the horizontal axis represents the diameter φ, and the vertical axis represents the light intensity. Note that the light intensity on the vertical axis is a value normalized by the total energy of the light. As shown in Fig. 21, as the diameter φ increases, the intensity ratio of the central beam to the ring beam increases. In the diffractive optical element 100 of the fourth example, too, the intensity ratio of the ring beam to the central beam can be adjusted according to the diameter of the incident light.

[0049] 22 is a plan view showing a fifth example of the structure of the diffractive optical element 100. In the fifth example, the first region 101 is a square with sides d5. Each region is formed so that a phase difference occurs between the phase of light that has passed through the first region 101 and the phase of light that has passed through the second region 102. The phase difference is preferably not less than (n-5 / 10)πrad and not more than (n+5 / 10)πrad, more preferably not less than (n-3 / 10)πrad and not more than (n+3 / 10)πrad, and even more preferably not less than (n-1 / 10)πrad and not more than (n+1 / 10)πrad. Here, n is any odd number.

[0050] Fig. 23 is a diagram showing the phase of light after passing through each region between D and D' when the diffractive optical element 100 shown in Fig. 22 is formed with a phase difference of π rad. The point of 0 on the horizontal axis corresponds to the center point O in Fig. 22. The vertical axis shows the phase of light based on the phase of light that has passed through the second region 102.

[0051] Figure 24 shows the results of a simulation of the intensity of diffracted light formed when the diffractive optical element 100 shown in Figure 22 is formed under the conditions of a phase difference of πrad and d5: 6.4 mm, and when light with diameters φ: 8.0 mm, 10.0 mm, 11.0 mm, and 15.0 mm is incident, assuming a combination with a focusing lens of F = +1 m.

[0052] Fig. 25 is a graph showing the light intensity of each ring beam and central beam of diffracted light for each diameter φ shown in Fig. 24. In Fig. 25, the horizontal axis represents the diameter φ, and the vertical axis represents the light intensity. Note that the light intensity on the vertical axis is a value normalized by the total energy of the light. As shown in Fig. 25, as the diameter φ increases, the intensity ratio of the central beam to the ring beam increases. In the diffractive optical element 100 of the fifth example, the intensity ratio of the ring beam to the central beam can also be adjusted according to the diameter of the incident light.

[0053] As described above, in any of the structures of the first to fifth examples, the intensity ratio between the central light and the ring light can be easily adjusted by adjusting the diameter of the incident light.

[0054] The first region 101, the second region 102, the third region 103, and the peripheral region 105 can be formed by forming irregularities on the diffractive optical element 100 by etching, vapor deposition, sputtering, CVD, or the like.

[0055] Furthermore, when the diffractive optical element 100 is a transmissive diffractive optical element, the first region 101, the second region 102, the third region 103, and the peripheral region 105 can also be formed by appropriately forming the spatial distribution of the refractive index of the diffractive optical element 100.

[0056] Next, it is preferable that the optical system 200 be able to adjust the diameter of the light incident on the diffractive optical element 100 as described above.

[0057] 26 to 28 are diagrams for explaining a first example of the details of the optical system 200. Each of Fig. 26 to Fig. 28 shows different states of the optical system 200 in the first example.

[0058] The optical system 200 has a collimating lens 210. The optical axis OA of light passing through the collimating lens 210, the diffractive optical element 100, and the condensing lens 300 passes through the center of the collimating lens 210, the center of the diffractive optical element 100, and the center of the condensing lens 300. The light that has passed through the collimating lens 210 is incident on the diffractive optical element 100. The collimating lens 210 is movable along the optical axis OA.

[0059] 27 and 28 are diagrams showing a state in which the collimator lens 210 is moved closer to the diffractive optical element 100 than in the state shown in Fig. 26. The state shown in Fig. 28 shows a state in which the collimator lens 210 is moved even closer to the diffractive optical element 100 than in the state shown in Fig. 27. As shown in Figs. 27 and 28, the diameter of light incident on the diffractive optical element 100 becomes larger as the collimator lens 210 gets closer to the diffractive optical element 100. In this way, the optical system 200 is able to adjust the diameter of light incident on the diffractive optical element 100 depending on the position of the collimator lens 210.

[0060] 29 to 31 are diagrams for explaining a second example of the details of the optical system 200. Each of Fig. 29 to Fig. 31 shows different states of the optical system 200 in the second example.

[0061] For example, as shown in FIG. 29 , the optical system 200 has a first lens 222, a second lens 224, and a third lens 226. The optical axis OA of light passing through the first lens 222, the second lens 224, the third lens 226, the diffractive optical element 100, and the condenser lens 300 passes through the center of the first lens 222, the center of the second lens 224, the center of the third lens 226, the center of the diffractive optical element 100, and the center of the condenser lens 300. The first lens 222 is a biconvex lens. The second lens 224 is a biconcave lens. The third lens 226 is a collimating lens. Light sent to the optical system 200 first passes through the first lens 222. In this case, the diameter of the light is reduced by the first lens 222. Next, the light passes through the second lens 224. In this case, the diameter of the light is expanded by the first lens 222. Next, the light passes through the third lens 226. In this case, the light is collimated by the third lens 226. The light then enters the diffractive optical element 100. The second lens 224 is movable along the optical axis OA between the first lens 222 and the third lens 226.

[0062] 30 and 31 are diagrams showing a state in which the second lens 224 is moved away from the third lens 226 from the state shown in Fig. 29. The state shown in Fig. 31 shows a state in which the second lens 224 is further away from the third lens 226 than the state shown in Fig. 30. As shown in Figs. 30 and 31, the diameter of light incident on the diffractive optical element 100 increases as the second lens 224 moves away from the third lens 226. In other words, the optical system 200 is capable of adjusting the diameter of light incident on the diffractive optical element 100 in accordance with the position of the second lens 224.

[0063] In this way, the optical system 200 can adjust the diameter of the light incident on the diffractive optical element 100. According to the optical device 10 of this embodiment, by adjusting the diameter of the light incident on the diffractive optical element 100, the intensity ratio between the central light and the ring light can be easily adjusted.

[0064] Second Embodiment In the first embodiment, the intensity ratio between the central light and the ring light is adjusted by adjusting the diameter of the light incident on the diffractive optical element 100. In the present embodiment, the intensity ratio between the central light and the ring light is adjusted by changing the structure of the diffractive optical element 100.

[0065] Figure 32 shows the results of a simulation of the intensity of diffracted light formed when the diffractive optical element 100 shown in Figure 8 is formed under the conditions of a constant phase difference of π rad, d2 of 10.0 mm, d1 values ​​of 5.0 mm, 4.0 mm, 10 / 3 mm, and 2.0 mm, and when light with a diameter φ of 8.0 mm is incident, assuming a combination with a focusing lens of F = +1 m.

[0066] Fig. 33 is a graph showing the light intensity of the ring light and the central light of the diffracted light in each diffractive optical element 100 shown in Fig. 32. In Fig. 33, the horizontal axis represents d1, and the vertical axis represents the light intensity. Note that the light intensity on the vertical axis is a value normalized by the total energy of the light. As shown in Fig. 33, as d1 increases, the intensity ratio of the central light decreases, and the intensity ratio of the ring light and the central light can be adjusted depending on the size of d1.

[0067] Furthermore, the intensity ratio between the central light and the ring light can be adjusted by changing the phase difference of the light that has passed through each region.

[0068] Figure 34 shows the results of a simulation of the intensity of diffracted light formed when the diffractive optical element 100 shown in Figure 3 is formed under conditions of 1.000πrad, 1.200πrad, and 1.225πrad, with d1 fixed at 10.0 mm, and light having a diameter of φ: 8.0 mm is incident, assuming a combination with a focusing lens of F = +1 m.

[0069] Fig. 35 is a graph showing the light intensities of the ring light and the central light for each diffractive optical element 100 shown in Fig. 34. In Fig. 35, the horizontal axis represents the phase difference, and the vertical axis represents the light intensity. Note that the light intensity on the vertical axis is a value normalized by the total energy of the light. As shown in Fig. 35, as the phase difference increases, the intensity ratio of the central light increases, and the intensity ratio of the ring light and the central light can be adjusted according to the phase difference of the light that has passed through each region.

[0070] As described above, according to this embodiment, the intensity ratio between the central light and the ring light can be easily adjusted by changing the size of each region or the phase difference of the light passing through each region of the diffractive optical element 100. Furthermore, by adjusting the diameter of the incident light in addition to the first embodiment, the diffracted light can be adjusted in more detail.

[0071] Third Embodiment In the first and second embodiments, the diffractive optical element 100 is used, but in this embodiment, a lens 500 is used instead of the diffractive optical element 100. The lens 500 has a first lens portion 501 and a second lens portion 502.

[0072] 36 is a diagram showing a first example of the configuration of the optical device 10 according to this embodiment. As shown in FIG. 36, the optical device 10 uses a lens 500 in this embodiment.

[0073] FIG. 37 is a plan view of a first example of a lens 500 according to this embodiment. FIG. 38 is a cross-sectional view taken along the line E-E' in FIG. 37. As shown in FIG. 37, the first lens portion 501 is formed in a circular shape. As shown in FIG. 38, in the lens 500, the first lens portion 501 has an axicon lens shape, and the second lens portion 502 has a planar shape. Therefore, the refraction angles of the first lens portion 501 and the second lens portion 502 are different. Light transmitted through the first lens portion 501 is refracted due to the shape of the axicon lens, whereas light transmitted through the second lens portion 502 travels straight through the planar shape and enters the condenser lens. Therefore, when light is incident on the first lens portion 501 and the second lens portion 502, both refracted light and straight-traveling light are generated. The refracted light forms a ring-shaped beam, and the straight-traveling light forms a central beam.

[0074] FIG. 39 shows the results of a simulation of the intensities of diffracted light formed when lens 500 shown in FIG. 38 is formed under the conditions that d6 is 8.0 mm and the angle θ of the axicon lens shape (see FIG. 34) is 0.05° and light beams having diameters φ of 4.0 mm, 5.2 mm, 5.8 mm, and 8.0 mm are incident thereon, assuming a combination with a focusing lens of F=+1 m.

[0075] Fig. 40 is a graph showing the light intensity of each ring beam and central beam of diffracted light for each diameter φ shown in Fig. 39. In Fig. 40, the horizontal axis represents the diameter φ, and the vertical axis represents the light intensity. As shown in Fig. 40, even when lens 500 is used, the intensity ratio of the central beam increases as the diameter φ increases, and the intensity ratio of the ring beam and the central beam can be adjusted according to the diameter of the incident light.

[0076] Moreover, the intensity ratio between the ring light and the central light can be adjusted by changing the structure of the lens 500 .

[0077] FIG. 41 shows the results of a simulation of the intensity of diffracted light formed when the lens 500 shown in FIG. 38 is formed under the conditions that the angle θ of the axicon lens shape is constant at 0.05°, and d6 is 12.0 mm, 11.0 mm, 10.5 mm, and 5.0 mm, and light with a diameter φ of 8.0 mm is incident, assuming a combination with a focusing lens of F=+1 m.

[0078] Fig. 42 is a graph showing the light intensity of the ring light and the central light of the diffracted light for each lens 500 shown in Fig. 41. As shown in Fig. 40, as the value of d6 decreases, the intensity ratio of the central light increases, and the intensity ratio of the ring light and the central light can be adjusted according to d6.

[0079] Next, a modified example of the lens 500 will be described.

[0080] Fig. 43 is a diagram showing a modified example of lens 500 according to this embodiment. In lens 500 shown in Fig. 43, second lens portion 502 having a diameter d7 is also formed inside first lens portion 501. Furthermore, similar to the first example, first lens portion 501 has an axicon lens shape, and second lens portion 502 has a planar shape.

[0081] FIG. 44 shows the results of a simulation in which the lens 500 shown in FIG. 43 is manufactured under the conditions that the angle θ of the axicon lens shape is 0.05°, the value of d7 is a constant 2.5 mm, and the values ​​of d6 are 12.0 mm, 11.0 mm, 10.5 mm, and 5.0 mm, and light with a diameter φ of 8.0 mm is incident on each lens 500, assuming a combination with a focusing lens of F=+1 m, and the intensity of diffracted light formed when the lens 500 is manufactured under the conditions that the angle θ of the axicon lens shape is 0.05°, the value of d7 is a constant 2.5 mm, and the values ​​of d6 are 12.0 mm, 11.0 mm, 10.5 mm, and 5.0 mm.

[0082] Fig. 45 is a graph showing the light intensity of the ring light and the central light of the diffracted light in each lens 500 shown in Fig. 44. As shown in Fig. 45, also in the modified lens 500, as the value of d6 decreases, the amount of light incident on the second lens portion 502 increases, and therefore the intensity ratio of the central light increases.

[0083] As described above, according to this embodiment, even when the lens 500 is used, the intensity ratio between the central light and the ring light can be easily adjusted by adjusting the diameter of the light incident on the lens 500. Moreover, the intensity ratio between the central light and the ring light can also be easily adjusted by changing the structure of the lens 500.

[0084] Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various other configurations can also be adopted.

[0085] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the descriptions of these examples.

[0086] Figure 46 shows the results of measuring the intensity of diffracted light obtained by forming the diffractive optical element 100 shown in Figure 3 on a flat quartz substrate with a 1 mm thick surface under the conditions of an optical path difference of 548 nm (phase difference of 1.03πrad) and d1: 6.4 mm. Laser light with a wavelength of 1064 nm was incident on the center of the element with diameters of φ: 8.0 mm, 10.0 mm, and 15.0 mm. The diffracted light was then combined with a focusing lens with F = +1 m and a beam profiler placed 1 m ahead of the optical system. The light intensity was normalized by the maximum light value measured by the profiler. With an incident light diameter of φ 8.0 mm, only a ring portion with a diameter of approximately 1 mm was visible; with a diameter of φ 10.0 mm, the intensity of the center and ring portion was similar; and with a diameter of φ 15.0 mm, the intensity of the central portion was dominant.

[0087] As with the simulation results shown in FIG. 6, the above example demonstrates that the intensity distribution ratio between the center and the ring portion can be adjusted by changing the diameter φ of the incident light.

[0088] This application claims priority based on Japanese Patent Application No. 2023-122871, filed on July 27, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0089] REFERENCE SIGNS LIST 10 Optical device 30 Light source 40 Optical fiber 100 Diffractive optical element 101 First region 102 Second region 103 Third region 105 Peripheral region 110 First surface 120 Second surface 200 Optical system 210 Collimating lens 222 First lens 224 Second lens 226 Third lens 300 Condenser lens 400 Storage section 500 Lens 501 First lens section 502 Second lens section

Claims

1. An optical device comprising: a diffractive optical element having a first region and a second region adjacent to the first region; and an optical system that irradiates light simultaneously onto the first region and the second region, wherein the difference between the phase of the light that has passed through the first region and the phase of the light that has passed through the second region is equal to or greater than (n1-5 / 10)π [rad] and equal to or less than (n1+5 / 10)π [rad], where n1 is any odd number.

2. The optical device according to claim 1, wherein the optical system is capable of varying the diameter of the incident light.

3. The optical device according to claim 1 or 2, wherein the first region is circular.

4. The optical device according to claim 3, wherein, when the intensity of the light at the center of the light is 100, the intensity of the light at the edge of the first region is 4 or more and 89 or less.

5. The optical device according to claim 3, wherein the diffractive optical element has a ring-shaped second region concentric with the first region.

6. The optical device according to claim 5, wherein, when the intensity of the light at the center of the light is 100, the intensity of the light at the edge of the first region is equal to or greater than 4 and less than 100, and the intensity of the light at the outer edge of the second region is greater than 0 and equal to or less than 89.

7. The optical device according to claim 5, wherein the diffractive optical element further has a ring-shaped third region adjacent to the second region, located outside the second region, and concentric with the first region; the optical system simultaneously irradiates light to the first region, the second region, and the third region; and a difference between the phase of the light that has passed through the second region and the phase of the light that has passed through the third region is equal to or greater than (n2-5 / 10)π [rad] and equal to or less than (n2+5 / 10)π [rad], n2 being any odd number.

8. The optical device according to claim 7, wherein, when the intensity of the light at the center of the light is 100, the intensity of the light at the edge of the first region is equal to or greater than 4 and less than 100, and the intensity of the light at the outer edges of the second region and the third region is greater than 0 and equal to or less than 89.

9. The optical device according to claim 1 or 2, wherein the first region is polygonal.

10. An optical device having a lens having a first lens portion and a second lens portion having a different light refraction angle from that of the first lens portion, and an optical system that irradiates light to the first lens portion and the second lens portion simultaneously.

11. The optical device according to claim 10, wherein the optical system is capable of varying a diameter of the incident light.

12. A method for shaping light, comprising using an optical device according to any one of claims 1, 2, 10 and 11.

13. A processing method, comprising processing an object using light shaped by the light shaping method according to claim 12.

Images