Beam shaping device and beam shaping method

Abstract

The embodiment of the invention provides a light beam shaping device, a light beam shaping system and a light beam shaping method, and relates to the technical field of light beam shaping, and the light beam shaping device comprises a Powell prism and a light beam homogenizing element which are arranged in sequence. The Powell prism can receive an incident beam, adjust a light path of the Powell prism according to the refractive index and the geometrical shape of the Powell prism and shape the incident beam into a linear emergent beam, and the beam homogenizing element can further shape the beam and increase the divergence angle of the emergent beam, so that the divergence angle of the emergent beam is an obtuse angle. And the light beams can be modulated by utilizing optical effects such as scattering and interference, so that uniform distribution of the light beams is realized.

Description

Technical Field

[0001] The present application relates to the technical field of beam shaping, and in particular to a beam shaping device and a beam shaping method. Background Art

[0002] Optical shaping is a technology that uses optical elements such as beam shaping lenses, mirrors or microlenses to convert a Gaussian incident laser beam into a circular, rectangular, square, straight line or other custom shapes. It is usually used in construction engineering, road surveying, medical imaging and laser processing.

[0003] How to achieve a linear beam with an ultra-large angle while ensuring a relatively uniform distribution of beam energy has become an important issue that technical personnel in this field need to solve urgently. Summary of the invention

[0004] In order to at least overcome the above-mentioned deficiencies in the prior art, the object of the present application is to provide a beam shaping device and a beam shaping method.

[0005] In a first aspect, an embodiment of the present application provides a beam shaping device, the beam shaping device comprising:

[0006] A Powell prism, wherein the Powell prism is used to receive an incident light beam and shape the incident light beam into a straight linear outgoing light beam;

[0007] A beam homogenizing element, the beam homogenizing element is used to increase the divergence angle of the outgoing beam and make the outgoing beam homogenized, wherein the divergence angle of the outgoing beam is greater than the incident angle of the incident beam, and the divergence angle of the outgoing beam is an obtuse angle.

[0008] In a possible implementation, the Powell prism has a curvature radius of 1.76, a thickness of 10 mm, and a cone coefficient of -1.91.

[0009] In a possible implementation, the beam homogenizing element includes a micro-nano element with a negative light focal length, and a microstructure is disposed on a surface of the micro-nano element.

[0010] In a possible implementation, the micro-nano element includes an incident surface and an exit surface that are arranged opposite to each other, and the incident surface and the exit surface include surface step structures.

[0011] In a possible implementation, the concavity of the surface step structure satisfies the following conditional formula:

[0012]

[0013] Among them, c is the curvature, k is the cone coefficient, r is the normalized radius, a i is the phase coefficient.

[0014] In a possible implementation, the curvature of the incident surface is -7.708, the cone coefficient is 0, and the normalized radius is 1;

[0015] The curvature of the exit surface is -7.915, the cone coefficient is 0, and the normalized radius is 1.

[0016] In a second aspect, an embodiment of the present application further provides a beam shaping system, comprising a light-emitting unit and a beam shaping device as described in any one of the first aspects, wherein the light-emitting unit is used to generate an incident light beam to be shaped, and send the incident light beam to the beam shaping device, and the beam shaping device shapes the incident light beam.

[0017] In a possible implementation, the light emitting unit includes a laser and a collimator, and the collimator is disposed between the laser and the Powell prism;

[0018] The laser is used to emit a light beam to be shaped, and the collimator is used to receive the light beam to be shaped emitted by the laser, convert the light beam to be shaped into a parallel incident light beam, and emit the parallel incident light beam to the Powell prism.

[0019] In a third aspect, an embodiment of the present application further provides a beam shaping method, which is applied to any beam shaping device described in the first aspect, and the method includes:

[0020] The Powell prism receives an incident light beam and performs a first shaping on the incident light beam to obtain a linear outgoing light beam;

[0021] The outgoing light beam is shaped for the second time by a beam homogenizing element to adjust the divergence angle of the outgoing light beam and make the outgoing light beam homogenized, wherein the divergence angle of the adjusted outgoing light beam is greater than the incident angle of the incident light beam, and the divergence angle of the adjusted outgoing light beam is an obtuse angle.

[0022] In a possible implementation, before the step of emitting an incident light beam by the laser, the method further includes:

[0023] Calculating design parameters of the beam homogenization element based on the parameters of the incident beam and the Powell prism, wherein the parameters include curvature, cone coefficient, normalized radius and phase coefficient;

[0024] The beam homogenization element is manufactured based on the design parameters, wherein the beam homogenization element comprises a micro-nano element, and a microstructure is arranged on a surface of the micro-nano element.

[0025] Based on any of the above aspects, the embodiments of the present application provide a beam shaping device and a beam shaping method, wherein the beam shaping device includes a Powell prism and a beam homogenizing element arranged in sequence. The Powell prism can receive an incident light beam, and adjust its light path by using its refractive index and geometric shape, so as to shape the incident light beam into a straight-line outgoing light beam, and the beam homogenizing element can not only further shape the light beam, increase the divergence angle of the outgoing light beam, so that the divergence angle of the outgoing light beam is an obtuse angle, but also modulate the light beam by using optical effects such as scattering and interference, so as to achieve uniform distribution of the light beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 A schematic diagram of the structure of a beam shaping device provided in an embodiment of the present application;

[0028] Figure 2 A schematic diagram of the optical path of an incident light beam passing through a Powell prism;

[0029] Figure 3 Schematic diagram of energy distribution of incident light beam;

[0030] Figure 4 is a schematic diagram of the light intensity distribution of the incident light beam;

[0031] Figure 5 Schematic diagram of energy distribution of the outgoing light beam;

[0032] Figure 6 is a schematic diagram of the light intensity distribution of the outgoing light beam;

[0033] Figure 7 A schematic diagram of parameters of a micro-nano element provided in an embodiment of the present application;

[0034] Figure 8 A schematic diagram of a flow chart of a beam shaping method provided in an embodiment of the present application;

[0035] Fig. 9 for Figure 8 A schematic diagram of a flow chart that may be included before step S110. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0038] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0039] In the description of this application, it should be noted that the terms "upper", "lower", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the application is usually placed when in use, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0040] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0041] It should be noted that, in the absence of conflict, different features in the embodiments of the present application may be combined with each other.

[0042] To solve the problems in the prior art, please refer to Figure 1 An embodiment of the present application provides a beam shaping device 10, which includes a Powell prism 110 and a beam homogenizing element 120 arranged in sequence.

[0043] The Powell prism 110 is an aspheric cylindrical mirror, and its top is a complex two-dimensional aspheric surface. After receiving the incident light beam, its refractive index and geometric shape can be used to adjust its light path, and the incident light beam can be shaped into a linear outgoing light beam. The beam homogenizing element 120 can further increase the divergence angle of the outgoing light beam and make the outgoing light beam homogenized, wherein the divergence angle of the outgoing light beam is greater than the incident angle of the incident light beam, and the divergence angle of the outgoing light beam is an obtuse angle.

[0044] Specifically, please refer to Figure 2 As shown in the optical path diagram, when the incident light beam is shaped by the Powell prism 110, the incident light beam follows the Fermat principle from point A to point B and from point O to point B, and the following relationship exists:

[0045]

[0046] Where y is the radius of the incident light beam and n is the refractive index.

[0047] It can also be concluded from the diagram that Since nsin(α)=sin(θ), it can be inferred from the actual processing design parameters that the divergence angle of the outgoing light beam of the Powell prism 110 is often limited to within 90°. For example, when the refractive index n is 1.51 and the radius y of the incident light beam is 0.75 mm, the divergence angle of the outgoing light beam of the Powell prism 110 is 47.88°.

[0048] On the basis of the above, adding a beam homogenizer 120 can not only further shape the light beam and increase the divergence angle of the outgoing light beam, but also modulate the light beam by using optical effects such as scattering and interference to achieve uniform distribution of the light beam. For example, when the divergence angle of the outgoing light beam of the Powell prism 110 is 47.88°, after further shaping and homogenization by the beam homogenizer, the divergence angle of the outgoing light beam of the beam homogenizer can reach 171.3°. It should be noted that the energy of the incident light beam is the same as the energy of the outgoing light beam. For details, please refer to Figures 3 to 6 , Figure 3 and Figure 4 are the energy distribution diagram and light intensity distribution diagram of the incident light beam, Figure 5 and Figure 6 They are the energy and intensity distribution diagrams of the outgoing beam respectively.

[0049] Furthermore, the Powell prism may have a radius of curvature of 1.76, a thickness of 10 mm, and a cone coefficient of -1.91.

[0050] Furthermore, the beam homogenizing element 120 may include an ultra-short focal length negative power lens, which can significantly increase the divergence angle of the outgoing light beam. However, as the divergence angle of the outgoing light beam increases, the focusing ability of the negative power lens on the outgoing light beam gradually weakens, which may cause a significant difference in brightness between the center and edge of the spot of the outgoing light beam, affecting the uniformity of the outgoing light beam.

[0051] To this end, the beam homogenizing element 120 in the embodiment of the present application adopts a micro-nano element with a negative focal length, and a microstructure is arranged on the surface of the micro-nano element. The micro-nano element with a negative focal length performs a second shaping on the outgoing beam of the Powell prism, further increasing the divergence angle of the outgoing beam, and can also homogenize the beam through the microstructure on the surface, so that the outgoing beam can achieve a super-large angle divergence while maintaining the uniformity of the steel beam.

[0052] Specifically, the micro-nano element includes an incident surface and an exit surface that are arranged opposite to each other, and the incident surface and the exit surface include a surface step structure, and the concavity of the surface step structure satisfies the following conditional formula:

[0053]

[0054] Among them, c is the curvature, k is the cone coefficient, r is the normalized radius, and a i is the phase coefficient.

[0055] For example, when the cone coefficient k is 0 and the normalized radius r is 1, the curvature c of the incident surface can be -7.708, the curvature c of the exit surface can be -7.915, and the phase coefficients can include a1, a2, a3, a4, a5, a6, a7 and a8. The specific values ​​can be referred to Figure 7 .

[0056] Based on the same inventive concept, an embodiment of the present application further provides a beam shaping system, which includes a light-emitting unit and any one of the beam shaping devices 10 in the above embodiments, wherein the light-emitting unit can be used to generate an incident light beam to be shaped, and send the incident light beam to the beam shaping device 10, and the beam shaping device 10 shapes the incident light beam.

[0057] Specifically, the light emitting unit may include a laser and a collimator, wherein the collimator is disposed between the laser and the Powell prism.

[0058] The laser is used to emit a light beam to be shaped, and the energy distribution of the light beam to be shaped satisfies the Gaussian distribution. For example, the light beam to be shaped may have a wavelength of 800 nm, and the energy p The irradiance distribution of a Gaussian beam with a waist diameter of 1.5 mm can be The total energy can be Where R is the beam diameter and r is the beam waist diameter.

[0059] The collimator is used to receive the incident light beam emitted by the laser, convert the incident light beam into a parallel incident light beam, and emit the parallel incident light beam to the Powell prism 110 to prevent factors such as light beam divergence or convergence from affecting the effect of beam shaping.

[0060] In addition, please refer to Figure 8 The embodiment of the present application may also provide a beam shaping method, which may be applied to the beam shaping device in any of the above embodiments. Figure 7 The beam shaping method is described in detail.

[0061] Step S110: The Powell prism receives the incident light beam and performs a first shaping on the incident light beam to obtain a linear outgoing light beam.

[0062] In this step, after receiving the incident light beam, the Powell prism can adjust its light path by using its refractive index and geometric shape to shape the incident light beam into a straight-line outgoing light beam. The incident light beam can be a Gaussian light beam with energy distribution that satisfies Gaussian distribution. For example, the incident light beam can be 800nm ​​in wavelength. The irradiance distribution of a Gaussian beam with a waist diameter of 1.5 mm can be The total energy can be Where R is the beam diameter and r is the beam waist diameter.

[0063] Step S120: The beam homogenizing element performs a second shaping on the outgoing beam, adjusts the divergence angle of the outgoing beam, and makes the outgoing beam homogenized.

[0064] Specifically, the beam homogenization element can not only further shape the light beam and increase the divergence angle of the outgoing light beam, so that the divergence angle of the adjusted outgoing light beam is greater than the incident angle of the incident light beam, and the divergence angle of the adjusted outgoing light beam is an obtuse angle, but also can utilize optical effects such as scattering and interference to modulate the light beam to achieve uniform distribution of the light beam.

[0065] For further information, please refer to Fig. 9 Before step S110, the beam shaping method provided by the embodiment of the present application may also include the following method.

[0066] Step S101: Calculating design parameters of a beam homogenizing element based on the parameters of the incident beam and the Powell prism.

[0067] In this step, the incident light beam can be 800nm ​​in wavelength and at an energy of The irradiance distribution of a Gaussian beam with a waist diameter of 1.5 mm can be The total energy can be Where R is the beam diameter and r is the beam waist diameter. The outgoing beam maintains a uniform maximum energy distribution within a diameter of 120 mm, and the irradiance distribution of the outgoing beam is a step function with a maximum value of h and a radius of m. The total energy of the outgoing beam is B = hΠy 2 According to the fact that the total energy of the outgoing beam is equal to the total energy of the incident beam (i.e. A = B), we can solve:

[0068]

[0069] It should be noted that in the above solution process, the coordinates of the incident light beam and the coordinates of the outgoing light beam need to be kept in one-to-one correspondence.

[0070] The incident light beam parameters may include parameters such as curvature, cone coefficient, normalized radius and phase coefficient.

[0071] It should be noted that this step can be calculated by simulation software such as Zemax or other computer-readable storage media.

[0072] Step S102: manufacturing a beam homogenizing element based on the design parameters.

[0073] In this step, the beam homogenizing element may include a micro-nano element, and a microstructure is arranged on the surface of the micro-nano element. Specifically, the micro-nano element includes an incident surface and an exit surface arranged opposite to each other, and the incident surface and the exit surface include a surface step structure, and the concavity of the surface step structure satisfies the following conditional formula:

[0074]

[0075] Among them, c is the curvature, k is the cone coefficient, r is the normalized radius, and a i is the phase coefficient.

[0076] Exemplarily, when the cone coefficient k is 0 and the normalized radius r is 1, the curvature c of the incident surface can be -7.708, the curvature c of the exit surface can be -7.915, and the phase coefficients can include a1, a2, a3, a4, a5, a6, a7 and a8. The specific values ​​can be referred to Table 1.

[0077] In summary, the embodiments of the present application provide a beam shaping device, a beam shaping system and a beam shaping method, wherein the beam shaping device comprises a Powell prism and a beam homogenizing element arranged in sequence. The Powell prism can receive an incident light beam, and adjust its light path by using its refractive index and geometric shape, so as to shape the incident light beam into a straight-line outgoing light beam, and the beam homogenizing element can not only further shape the light beam, increase the divergence angle of the outgoing light beam, so that the divergence angle of the outgoing light beam is an obtuse angle, but also modulate the light beam by using optical effects such as scattering and interference, so as to achieve uniform distribution of the light beam.

[0078] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A beam shaping device, characterized in that: The beam shaping device comprises: A Powell prism, wherein the Powell prism is used to receive an incident light beam and shape the incident light beam into a straight linear outgoing light beam; A beam homogenizing element, the beam homogenizing element is used to increase the divergence angle of the outgoing beam and make the outgoing beam homogenized, wherein the divergence angle of the outgoing beam is greater than the incident angle of the incident beam, and the divergence angle of the outgoing beam is an obtuse angle.

2. The beam shaping device according to claim 1, characterized in that: The Powell prism has a curvature radius of 1.76, a thickness of 10 mm, and a cone coefficient of -1.

91.

3. The beam shaping device according to claim 1, characterized in that: The light beam homogenizing element comprises a micro-nano element with a negative light focal length, and a microstructure is arranged on the surface of the micro-nano element.

4. The beam shaping device according to claim 3, characterized in that: The micro-nano element comprises an incident surface and an exit surface which are arranged opposite to each other, and the incident surface and the exit surface comprise surface step structures.

5. The beam shaping device according to claim 4, characterized in that: The concavity of the surface step structure satisfies the following conditional formula: Among them, c is the curvature, k is the cone coefficient, r is the normalized radius, a i is the phase coefficient.

6. The beam shaping device according to claim 5, characterized in that: The curvature of the incident surface is -7.708, the cone coefficient is 0, and the normalized radius is 1; The curvature of the exit surface is -7.915, the cone coefficient is 0, and the normalized radius is 1.

7. A beam shaping system, characterized in that: The beam shaping system comprises a light-emitting unit and the beam shaping device according to any one of claims 1 to 6, wherein the light-emitting unit is used to generate an incident light beam to be shaped, and send the incident light beam to the beam shaping device, and the beam shaping device shapes the incident light beam.

8. The beam shaping system according to claim 5, characterized in that: The light emitting unit comprises a laser and a collimator, wherein the collimator is arranged between the laser and the Powell prism; The laser is used to emit a light beam to be shaped, and the collimator is used to receive the light beam to be shaped emitted by the laser, convert the light beam to be shaped into a parallel incident light beam, and emit the parallel incident light beam to the Powell prism.

9. A beam shaping method, characterized in that: Applied to the beam shaping device according to any one of claims 1 to 6, the method comprising: The Powell prism receives an incident light beam and performs a first shaping on the incident light beam to obtain a linear outgoing light beam; The outgoing light beam is shaped for the second time by a beam homogenizing element to adjust the divergence angle of the outgoing light beam and make the outgoing light beam homogenized, wherein the divergence angle of the adjusted outgoing light beam is greater than the incident angle of the incident light beam, and the divergence angle of the adjusted outgoing light beam is an obtuse angle.

10. The beam shaping method according to claim 8, characterized in that: Before the step of emitting an incident light beam by the laser, the method further comprises: Calculating design parameters of the beam homogenization element based on the parameters of the incident beam and the Powell prism, wherein the parameters include curvature, cone coefficient, normalized radius and phase coefficient; The beam homogenization element is manufactured based on the design parameters, wherein the beam homogenization element comprises a micro-nano element, and a microstructure is arranged on a surface of the micro-nano element.

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