Beam shaping device for obtaining a micron-level square uniform light spot and laser equipment

Abstract

The application belongs to the technical field of optical shaping systems, and discloses a light beam shaping device for obtaining a micron-level square uniform light spot and a laser device, which comprises a first lens, a second lens, a third lens and an irradiation surface which are sequentially and spaced apart along an optical axis from front to back. The first lens is used for modulating an incident Gaussian light beam. The second lens is used for converting light into parallel light. The third lens is used for focusing to form a micron-level square uniform light spot. Thus, the problem that a micron-level square uniform light spot is difficult to obtain in the prior art is solved. The device has the advantages of being capable of obtaining a micron-level square uniform light spot, high light energy utilization rate and low cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical shaping systems, in particular to a light beam shaping device for obtaining a micron-level square uniform light spot and a laser device. BACKGROUND

[0002] With the development of laser technology, the application demand of micron-level small-size uniform light spot (referring to the light spot in the size range of several microns to hundreds of microns) gradually increases in the industrial and scientific research fields. For example, in the fields of microscopic illumination, micro-welding, drilling, and material micro-processing, the light spot size is usually required to be several microns to hundreds of microns, and the light intensity distribution is required to be uniform. In the display manufacturing field, such as laser lift-off and transfer of Micro-LED chips, not only is the light spot size required to be in the micron level, but also the light spot distribution is required to be rectangular or square uniform.

[0003] However, the laser output beam is usually near-Gaussian distribution, and the laser output near-Gaussian beam needs to be homogenized and shaped to obtain a small-size uniform light spot. Traditional light beam shaping methods based on geometric optics, such as refractive prism light beam shaping, free-form refractive lens shaping, microlens array light beam shaping, and light guide tube light beam shaping, can usually only obtain uniform light spots with sizes of millimeters or more. For micron-scale light spots, the diffraction effect is more obvious, and the light beam shaping light path needs to be designed and analyzed from the perspective of physical optics.

[0004] There are two common methods for obtaining micron-level uniform light spots. One method is to use two free-form lenses to convert the incident Gaussian beam into a larger circular Airy spot, and then use a converging lens to focus the Airy spot to obtain a small-size uniform light spot. However, this method can only obtain a circular light spot. The other method is to use a diffractive optical element (DOE) to modulate the phase of the incident Gaussian beam, and then use a converging lens to converge the DOE-modulated light beam into a small-size uniform light spot. Although a small-size rectangular light spot can be obtained, the high-quality DOE has a high processing cost, and the DOE diffraction will lose part of the light energy, reducing the light energy utilization.

[0005] Therefore, the prior art needs to be improved. SUMMARY

[0006] The purpose of the present application is to provide a light beam shaping device for obtaining a micron-level square uniform light spot and a laser device, which can obtain a micron-level square uniform light spot, has low cost, and has high light energy utilization.

[0007] In a first aspect, the present application provides a light beam shaping device for obtaining a micron-level square uniform light spot, comprising a first lens, a second lens, a third lens and an irradiation surface which are sequentially and spaced apart along an optical axis from front to back.

[0008] The first lens is used for modulating the light ray angle of the incident Gaussian light beam, so that the light intensity distribution of the modulated light beam on the front surface of the second lens conforms to a sinc function profile in the x-axis direction and the y-axis direction; the x-axis direction and the y-axis direction are perpendicular to each other and are both perpendicular to the optical axis;

[0009] The second lens is used for changing the refraction angle of the light rays incident on the second lens, so that the light rays are re-converted into parallel light and exit;

[0010] The third lens is a focusing lens and is used for focusing the exiting light of the second lens on the irradiation surface to form a micron-level square uniform light spot.

[0011] The light beam shaping device includes a first lens, a second lens, a third lens and an irradiation surface arranged in sequence along an optical axis from front to back. The first lens is used for modulating the incident Gaussian light beam, the second lens is used for converting the light rays into parallel light, and the third lens is used for focusing to form a micron-level square uniform light spot. Thus, the problem that it is difficult to obtain a micron-level square uniform light spot in the prior art is solved, and the light beam shaping device has the advantages of being able to obtain a micron-level square uniform light spot, high light energy utilization rate and low cost.

[0012] Preferably, the front surface of the first lens is a plane, and the rear surface is a curved surface. The rear surface of the first lens is used for modulating the light ray angle of the incident Gaussian light beam.

[0013] Through the special structural design of the first lens, effective modulation of the incident Gaussian light beam is realized. After the incident Gaussian light beam passes through the first lens, the light ray angle is accurately controlled, so that the light beam can form a specific light intensity distribution when reaching the front surface of the second lens, that is, the light intensity distribution conforms to a sinc function profile in the x-axis and y-axis directions. This light intensity distribution lays a foundation for subsequent light beam shaping and uniformization, and ultimately helps to form a micron-level square uniform light spot on the irradiation surface.

[0014] Preferably, the front surface of the second lens is a curved surface, and the rear surface is a plane. The front surface of the second lens is used for changing the refraction angle of the light rays incident on the second lens, so that the light rays are re-converted into parallel light and exit.

[0015] The second lens has a curved front surface and a flat rear surface, effectively changing the angle of refraction of the incident light. Specifically, the curved front surface refracts the incident light, changing its direction of propagation; the flat rear surface maintains the parallelism of the outgoing light; and the combined design of the front and rear surfaces allows the light passing through the second lens to be reconverted into parallel light for outgoing emission. This design, in conjunction with the first and third lenses, achieves the goal of shaping the incident Gaussian beam into a micron-scale square uniform spot. The second lens plays a key "corrective" role in the entire optical path, ensuring that the light beam can be reconverted into parallel light after being modulated by the first lens, providing excellent optical conditions for subsequent focused imaging.

[0016] Preferably, the third lens is a biconvex spherical lens or a plano-convex spherical lens.

[0017] Preferably, the two-dimensional sag of the topography of the rear surface of the first lens and the two-dimensional sag of the topography of the front surface of the second lens satisfy the following relationship:

[0018] ;

[0019] ;

[0020] ;

[0021] ;

[0022] ;

[0023] ;

[0024] in, and are the plane position coordinates of the points on the back surface of the first lens and the front surface of the second lens passed by the same light, is the x-axis coordinate, is the y-axis coordinate, The back surface of the first lens corresponds to The two-dimensional vector height of the position, The front surface of the second lens corresponds to The two-dimensional vector height of the position, The back surface of the first lens corresponds to The one-dimensional vector height of the position, The back surface of the first lens corresponds to The one-dimensional vector height of the position, The front surface of the second lens corresponds to The one-dimensional vector height of the position, the front surface of the second lens corresponds to a sinc function in the y-axis direction one-dimensional sag of the position, refractive index of the first lens to an incident Gaussian light beam, refractive index of the second lens to an incident Gaussian light beam, s is the distance between the back surface of the first lens and the front surface of the second lens, x-axis direction light ray turning point coordinate, y-axis direction light ray turning point coordinate.

[0025] Preferably, and satisfy the following relationship:

[0026] ;

[0027] ;

[0028] wherein, waist radius of the incident Gaussian light beam, maximum light intensity of the front surface of the second lens corresponding to a sinc function in the x-axis direction, maximum light intensity of the front surface of the second lens corresponding to a sinc function in the y-axis direction, x-axis direction clear aperture radius of the exit light beam of the back surface of the second lens, y-axis direction clear aperture radius of the exit light beam of the back surface of the second lens.

[0029] Preferably, the distance between the irradiation surface and the third lens is adjustable.

[0030] Preferably, the region where the light intensity of the micron-level square uniform light spot is not less than 30% of the maximum light intensity of the micron-level square uniform light spot is the effective light spot region, and the size of the effective light spot region satisfies the following conditions:

[0031] ;

[0032] ;

[0033] wherein, x-axis direction size of the effective light spot region, y-axis direction size of the effective light spot region, wavelength of the incident Gaussian light beam, focal length of the third lens, distance of the irradiation surface from the focal plane of the third lens.

[0034] In a second aspect, the application provides a laser device, comprising a laser and a beam shaping device, wherein the beam shaping device is the beam shaping device for obtaining a micron-level square uniform light spot as described above, and the laser is configured to emit a Gaussian light beam to the beam shaping device, and the beam shaping device is configured to shape the Gaussian light beam into a micron-level square uniform light spot.

[0035] Beneficial effects: the beam shaping device for obtaining a micron-level square uniform light spot and the laser device provided by the application comprise a first lens, a second lens, a third lens and an irradiation surface which are sequentially and spaced apart along an optical axis, the first lens is configured to modulate an incident Gaussian light beam, the second lens is configured to convert light into parallel light, and the third lens is configured to focus to form a micron-level square uniform light spot, thereby solving the problem that it is difficult to obtain a micron-level square uniform light spot in the prior art, and the device has the advantages of being able to obtain a micron-level square uniform light spot, high light energy utilization rate and low cost. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The structure diagram of the beam shaping device for obtaining a micron-level square uniform light spot provided by the embodiment of the application.

[0037] Figure 2 The topography diagram of the rear surface of the first lens.

[0038] Figure 3 The topography diagram of the front surface of the second lens.

[0039] Figure 4 The one-dimensional height diagram of the rear surface of the first lens and the front surface of the second lens along the x-axis direction at y=0.

[0040] Figure 5 The light intensity distribution diagram of the light beam at different positions.

[0041] Figure 6 The light spot topography diagram corresponding to different offset distances.

[0042] Label explanation: 1, first lens; 2, second lens; 3, third lens; 4, irradiation surface. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work belong to the scope of protection of the present application.

[0044] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. Meanwhile, in the description of the present application, the terms "first", "second", etc. are only used for differentiation in description, and cannot be understood as indicating or implying relative importance.

[0045] With the rapid development of laser technology, the application demand of micron-level light spots in industrial and scientific research fields is growing. From the initial millimeter-level light spot shaping to the current precise control of micron-level light spots, beam shaping technology has undergone significant progress. However, at the micron scale, the diffraction effect of light becomes more obvious, and the traditional geometric optics method is difficult to meet the requirements.

[0046] Currently, there are mainly two methods to obtain micron-level uniform light spots: using a free-form surface lens to convert an incident Gaussian beam into a circular Airy spot pattern and then combining it with a converging lens, but only a circular spot can be obtained; using a diffractive optical element (DOE) and a converging lens combination, a rectangular spot can be obtained, but there are problems of high processing cost and light energy loss. These methods still have limitations in some application scenarios.

[0047] Taking the manufacturing of Micro-LED chips as an example, during the laser lifting and transferring process, micron-level square uniform light spots are needed. The traditional method is difficult to meet the requirements of light spot shape, size and uniformity at the same time. In a Micro-LED display production line, engineers are facing the challenge of how to accurately control the laser spot to improve the success rate of chip transfer. The display chip shape is usually square, and the circular light spot will reduce the light spot energy utilization rate. Although the DOE can obtain a square light spot, the high-precision DOE processing cost is high, and the DOE diffraction will also cause part of the light energy loss. Both of the above cases will increase the production line production cost.

[0048] In order to solve these problems, a new beam shaping device design is proposed in the present application.

[0049] Please refer to Figure 1 ,Figure 1 is a light beam shaping device for obtaining a micron-level square uniform light spot in some embodiments of the present application, comprising a first lens 1, a second lens 2, a third lens 3 and an irradiation surface 4 arranged in sequence along an optical axis from front to back;

[0050] The first lens 1 is used to modulate the angle of the light rays of the incident Gaussian light beam, so that the light intensity distribution of the modulated light beam on the front surface of the second lens 2 conforms to the sinc function topography along the x-axis direction and the y-axis direction; the x-axis direction and the y-axis direction are perpendicular to each other and perpendicular to the optical axis (wherein the z-axis in the xyz coordinate system coincides with the optical axis, and the x-axis, the y-axis and the z-axis form a right-handed coordinate system);

[0051] The second lens 2 is used to change the refraction angle of the light rays incident on the second lens 2, so that the light rays are reconverted into parallel light (specifically, the outgoing light is parallel to the optical axis);

[0052] The third lens 3 is a focusing lens and is used to focus the outgoing light of the second lens 2 on the irradiation surface 4 to form a micron-level square uniform light spot.

[0053] The light beam shaping device comprises a first lens, a second lens, a third lens and an irradiation surface arranged in sequence along an optical axis from front to back, the incident Gaussian light beam is modulated by the first lens, the light rays are converted into parallel light by the second lens, and the third lens focuses to form a micron-level square uniform light spot, thereby solving the problem that it is difficult to obtain a micron-level square uniform light spot in the prior art, and having the advantages of being able to obtain a micron-level square uniform light spot, high light energy utilization rate and low cost.

[0054] In some embodiments, see Figure 1 The front surface of the first lens 1 is a plane, and the rear surface is a curved surface, and the rear surface of the first lens 1 is used to modulate the angle of the light rays of the incident Gaussian light beam.

[0055] Specifically, the front surface of the first lens 1 is a plane, which can ensure that the incident Gaussian light beam does not undergo initial refraction when entering the first lens 1, which helps to maintain the original characteristics of the light beam. The rear surface of the first lens 1 is a curved surface, which is the core of the light ray angle modulation. By carefully designing the shape of the curved surface, different degrees of refraction can be achieved for light rays at different positions, thereby achieving angle modulation of the entire light beam. Concentrating the modulation function on the rear surface can simplify the optical path design, and also facilitate accurate control of the modulation effect.

[0056] The rear surface curved surface of the first lens 1 is preferably a free curved surface, which has high flexibility and can be customized designed for different incident light beam characteristics.

[0057] By the special structure design of the first lens 1, the effective modulation of the incident Gaussian beam is realized. After the incident Gaussian beam passes through the first lens 1, the light ray angle is accurately regulated, so that the light beam can form a specific light intensity distribution when reaching the front surface of the second lens 2, that is, it conforms to the sinc function topography in the x-axis and y-axis directions. This light intensity distribution lays the foundation for subsequent beam shaping and homogenization, and ultimately helps to form a micron-level square uniform light spot on the irradiation surface.

[0058] Compared with the traditional multi-element beam shaping system, the technical scheme of the present application has the advantages of simple structure and high optical efficiency. Since only one specially designed lens is used to realize the complex beam modulation function, the structure of the optical system is greatly simplified, the interface reflection loss between the optical elements is reduced, and the overall light energy utilization rate is improved. At the same time, the modulation scheme of the single lens also reduces the alignment difficulty and assembly complexity of the system, improves the stability and reliability of the system.

[0059] In some embodiments, see Figure 1 The front surface of the second lens 2 is a curved surface, and the rear surface is a flat surface. The front surface of the second lens 2 is used to change the refraction angle of the light rays incident on the second lens 2, so that the light rays are reconverted into parallel light out.

[0060] The design of the front surface of the second lens 2 as a curved surface and the rear surface as a flat surface can effectively change the refraction angle of the incident light. Specifically: the curved front surface can refract the incident light and change its propagation direction; the flat rear surface can maintain the parallelism of the outgoing light; the combination design of the front and rear surfaces makes the light after the second lens reconverted into parallel light out. This design cooperates with the first lens 1 and the third lens 3 to achieve the purpose of shaping the incident Gaussian beam into a micron-level square uniform light spot. The second lens 2 plays a key "correction" role in the entire optical path, ensuring that the light beam can be reconverted into parallel light after being modulated by the first lens 1, providing good optical conditions for subsequent focusing imaging.

[0061] The front surface of the second lens 2 is preferably a free-form surface, which has high flexibility and can be customized designed for different incident beam characteristics.

[0062] The rear surface of the second lens 2 is a flat surface, which can ensure the parallelism of the outgoing light. The flat structure is relatively simple and has low processing difficulty, which is conducive to improving the overall manufacturing precision and consistency. At the same time, the flat rear surface can also reduce the reflection and scattering of the light beam inside the lens, improving the light energy utilization rate.

[0063] The combined design of the front and back surfaces of the second lens 2 creates a unique optical structure. Incident light is first refracted by the curved front surface, changing its direction of propagation. This refraction compensates for the diverging or converging effects of the first lens 1. Subsequently, the light remains essentially parallel as it passes through the flat rear surface, thus achieving the goal of converting the incident light back into parallel light.

[0064] In some embodiments, the third lens 3 is a biconvex spherical lens or a plano-convex spherical lens. Figure 1 In the embodiment, the third lens 3 is a biconvex spherical lens.

[0065] The third lens 3, acting as a focusing lens, is crucial for achieving a uniform, square, micrometer-level light spot. Biconvex and plano-convex spherical lenses are both commonly used focusing lens types, offering excellent focusing performance. Choosing a biconvex or plano-convex spherical lens as the third lens 3 effectively focuses the parallel light output from the second lens 2 onto the illumination surface 4, forming the desired uniform, micrometer-level light spot.

[0066] Both biconvex and planoconvex spherical lenses have their own advantages as the third lens element. Biconvex spherical lenses, with both sides convex, have lower aberrations and can produce higher-quality focusing effects. Planoconvex lenses, with one side flat and the other convex, have slightly greater spherical aberration than biconvex lenses. However, in the present invention, they can provide focusing effects similar to those of biconvex lenses and are easier to manufacture and install.

[0067] In some preferred embodiments, the two-dimensional sag of the topography of the rear surface of the first lens 1 and the two-dimensional sag of the topography of the front surface of the second lens 2 satisfy the following relationship:

[0068] ;

[0069] ;

[0070] ;

[0071] ;

[0072] ;

[0073] ;

[0074] in, and are the plane position coordinates of the points on the back surface of the first lens 1 and the front surface of the second lens 2 that are passed by the same light (hereinafter referred to as corresponding points), is the x-axis coordinate, is the y-axis coordinate, The back surface of the first lens 1 corresponds to a two-dimensional height of the position point corresponding to the rear surface of the first lens 1 with respect to the center point in the z-axis direction, a two-dimensional height of the position point corresponding to the rear surface of the first lens 1 with respect to the center point in the z-axis direction, a one-dimensional height of the position point corresponding to the front surface of the second lens 2 in the x-axis direction, a two-dimensional height of the position point corresponding to the front surface of the second lens 2 with respect to the center point in the z-axis direction, a two-dimensional height of the position point corresponding to the front surface of the second lens 2 with respect to the center point in the z-axis direction, a one-dimensional height of the position point corresponding to the rear surface of the first lens 1 in the x-axis direction, a one-dimensional height of the position point corresponding to the rear surface of the first lens 1 in the x-axis direction, a one-dimensional height of the position point corresponding to the rear surface of the first lens 1 in the x-axis direction, a one-dimensional height of the position point corresponding to the rear surface of the first lens 1 in the y-axis direction, a one-dimensional height of the position point corresponding to the rear surface of the first lens 1 in the y-axis direction, a one-dimensional height of the position point corresponding to the rear surface of the first lens 1 in the y-axis direction, a one-dimensional height of the position point corresponding to the front surface of the second lens 2 in the x-axis direction, a one-dimensional height of the position point corresponding to the front surface of the second lens 2 in the x-axis direction, a one-dimensional height of the position point corresponding to the front surface of the second lens 2 in the x-axis direction, a one-dimensional height of the position point corresponding to the front surface of the second lens 2 in the y-axis direction, a one-dimensional height of the position point corresponding to the front surface of the second lens 2 in the y-axis direction, a one-dimensional height of the position point corresponding to the front surface of the second lens 2 in the y-axis direction, a refractive index of the first lens 1 to an incident Gaussian beam, a refractive index of the second lens 2 to an incident Gaussian beam, s is a distance between the rear surface of the first lens 1 and the front surface of the second lens 2 (specifically, a distance from a center point of the rear surface of the first lens 1 to a center point of the front surface of the second lens 2, as shown in FIG. 2), Figure 1 a turning point coordinate of an x-axis direction light ray, a turning point coordinate of an x-axis direction light ray, a turning point coordinate of an x-axis direction light ray.

[0075] wherein, and satisfy the following relationships:

[0076] (1);

[0077] (2);

[0078] wherein, the waist radius of the incident Gaussian beam, the maximum light intensity of the sinc function corresponding to the x-axis direction of the front surface of the second lens 2, the maximum light intensity of the sinc function corresponding to the y-axis direction of the front surface of the second lens 2, the entrance pupil radius of the exit beam of the back surface of the second lens 2 in the x-axis direction (the design value is 0.5 mm), the entrance pupil radius of the exit beam of the back surface of the second lens 2 in the y-axis direction (the design value is 0.5 mm). That is, and the corresponding can be determined by the above formula (1) and formula (2).

[0079] wherein, , substitute formula (1) to calculate ; can be substituted , formula (2) to calculate ; the entrance pupil radius of the Gaussian beam in the x-axis direction of the back surface of the first lens 1 (the design value is 0.5 mm), the entrance pupil radius of the Gaussian beam in the y-axis direction of the back surface of the first lens 1 (the design value is 0.5 mm).

[0080] wherein, substitute formula (1) to calculate , substitute formula (2) to calculate .

[0081] The back surface of the first lens 1 with the above-mentioned topography can effectively convert the incident Gaussian beam into a light intensity distribution conforming to the sinc function topography; at the same time, cooperating with the front surface of the second lens 2 with the above-mentioned topography, the light beam modulated by the back surface of the first lens 1 can be effectively converted into a parallel light beam again.

[0082] The size of the light spot formed on the irradiation surface 4 after being focused by the third lens 3 is related to the distance from the irradiation surface 4 to the third lens 3. Therefore, in some preferred embodiments, the distance between the irradiation surface 4 and the third lens 3 is adjustable.

[0083] By making the distance between the irradiation surface 4 and the third lens 3 adjustable, the precise position of the micron-level square light spot can be captured. The third lens 3 acts as a focusing lens to focus the exit light of the second lens 2 on the irradiation surface to form a micron-level square uniform light spot. By adjusting the distance between the irradiation surface 4 and the third lens 3, the position of light convergence can be changed, so that the square light spot topography consistent with the theoretical result is obtained.

[0084] This adjustable design can be implemented in various ways. For example, a precision linear translation stage can be placed between the illumination surface 4 and the third lens 3, and the distance is adjusted by controlling the movement of the translation stage. Another method is to use a screw mechanism to precisely adjust the position of the illumination surface 4 by rotating the screw. A piezoelectric ceramic driver can also be used to achieve fine adjustment of the distance, taking advantage of its micron-level precision control capability.

[0085] Specifically, the region where the light intensity of the micron-level square uniform light spot is not less than 30% of the maximum light intensity of the micron-level square uniform light spot is the effective light spot area, and the size of the effective light spot area satisfies the following conditions:

[0086] (3) ;

[0087] (4) ;

[0088] wherein, is the size of the effective light spot area in the x-axis direction, is the size of the effective light spot area in the y-axis direction, is the wavelength of the incident Gaussian beam, is the focal length of the third lens 3, is the offset distance of the illumination surface 4 from the focal plane of the third lens 3.

[0089] In this application, the effective light spot area is defined as the region where the light intensity is not less than 30% of the maximum light intensity. This definition helps to determine the actual available light spot range and improve the accuracy of light spot size evaluation. In fact, the threshold value can not be limited to 30%, but choosing 30% as the threshold value is the preferred result based on the simulation results of the light spot size, for example, if 25% or 35% is chosen as the measurement standard, the size evaluation accuracy of formulas (3), (4) will decrease slightly.

[0090] Therefore, when adjusting the distance between the illumination surface 4 and the third lens 3, the size of the effective light spot area can be used as a reference to make the size of the effective light spot area equal to the target light spot size.

[0091] The materials of the first lens 1, the second lens 2 and the third lens 3 can be, but are not limited to, common optical glasses (such as BK7, K9, etc.), fused quartz or special optical glasses. Preferably, the material is fused quartz, which has high light transmittance and low dispersion characteristics, can reduce the energy loss and chromatic aberration of the light beam when passing through the lens, and helps to maintain the quality and uniformity of the light beam. At the same time, fused quartz has a high melting point and thermal stability, can maintain good performance in high-power laser applications, and is not easy to deform or damage due to thermal effects. In addition, fused quartz has good corrosion resistance to most chemicals and can be used for a long time in various environments without degradation. Fused quartz can also be precisely machined into the required shape and surface quality, which is beneficial to achieve complex optical surface designs, such as the specific curved surface topography of the rear surface of the first lens 1 and the front surface of the second lens 2.

[0092] The selection of the fused quartz material in combination with other technical features in the present application produces significant technical effects. For example, the high light transmittance and low dispersion characteristics of fused quartz in combination with the precise modulation of the first lens 1 to the light angle can ensure the formation of a high-quality sinc function light intensity distribution at the front surface of the second lens 2. At the same time, the excellent machining performance of fused quartz enables the front surface of the second lens 2 to accurately achieve the required curved surface topography, thereby accurately changing the light refraction angle and outputting parallel light. Finally, the thermal stability of the fused quartz material in combination with the focusing function of the third lens can maintain a stable micron-level square uniform light spot in high-power laser applications.

[0093] In one specific embodiment, a beam shaping device for obtaining a micron-level square uniform light spot is provided, which has a wavelength of 266 nm, a beam waist radius of 1.5 mm, a first lens 1 with a clear aperture of 60 mm, a second lens 2 with a clear aperture of 60 mm, a distance s between the rear surface of the first lens 1 and the front surface of the second lens 2 of 60 mm, and a third lens 3 with a focal length of 75 mm. Figure 2 Figure 3 Figure 2 Figure 3 Figure 4 Figure 4 ​​​​​​​​​​In FIG, h' represents the one-dimensional vector height, h1 represents the one-dimensional vector height corresponding to the rear surface of the first lens 1, and h2 represents the one-dimensional vector height corresponding to the front surface of the second lens 2). Figure 5 Shows When the diameter of the lens element is 0.08 mm, the light intensity distribution at the front surface of the first lens 1, the back surface of the second lens 2, and the irradiation surface 4 (in the figure, L1 represents the first lens 1, L2 represents the second lens 2, and L3 represents the irradiation surface 4). In the figure, the upper image shows the light intensity distribution diagram, and the lower image shows the distribution morphology of the light intensity on the x-axis and y-axis (the distribution morphology of the two axes is the same, in the distribution morphology, the horizontal axis represents the position, its unit is millimeter, and the vertical axis is the normalized light intensity). Figure 5 It can be seen that a micron-level square uniform light spot can be obtained. Adjust from -0.28mm to 0.2mm to get different The corresponding light intensity distribution shape of the irradiation surface 4 on the x-axis is as follows: Figure 6 As shown in the figure, we can see that When the diameter is -0.17mm, 0.08mm and 0.16mm, a good quality micron-level square uniform light spot can be obtained (it can be seen that only a few specific positions near the focal plane of the third lens L3 can obtain a relatively ideal square light spot. The position of the irradiation surface 4 is set to be adjustable. By adjusting the position of the irradiation surface 4, the accurate deviation distance of the square light spot can be searched). ),when When the diameter is -0.17 mm, the size of the effective spot area where the light intensity is not less than 30% of the maximum light intensity is approximately 9.8 μm × 9.8 μm, which is consistent with the calculated results of formula (3) and formula (4), which are 9.98 μm × 9.98 μm.

[0094] It should be noted that the present application does not impose any restrictions on the thicknesses of the first lens 1, the second lens 2, and the third lens 3, nor does it impose any restrictions on the distance t between the second lens 2 and the third lens 3. This reduces the requirements for the thickness processing accuracy and relative position accuracy of each optical element, thereby reducing component manufacturing costs and the difficulty of optical path debugging.

[0095] In the second aspect, the present application provides a laser device, including a laser and a beam shaping device. The beam shaping device is the beam shaping device mentioned above for obtaining a micron-level square uniform light spot. The laser is used to emit a Gaussian beam to the beam shaping device, and the beam shaping device is used to shape the Gaussian beam into a micron-level square uniform light spot.

[0096] The laser device is any device that needs to use a micron-level square uniform light spot to process a workpiece, such as a laser device used for laser peeling of Micro-LED chips, but is not limited to this.

[0097] In summary, the light beam shaping device for obtaining a micron-level square uniform light spot and the laser equipment have the following advantages:

[0098] 1. The light beam shaping light path is designed based on geometric ray tracing, and the light spot appearance is analyzed based on diffraction transmission algorithm, so that a micron-level size uniform light spot can be obtained;

[0099] 2. Two pieces of free-form surface lenses are used to shape the x and y directions of the Gaussian light beam, so that a square uniform light spot can be obtained;

[0100] 3. Compared with the existing shaping method based on DOE, the two pieces of free-form surface refractive lenses used in the present application have lower cost and higher light energy utilization.

[0101] The above only describes the embodiments of the present application and is not used to limit the protection scope of the present application. For those skilled in the art, the present application can have various modifications and changes. 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 for obtaining a micron-level square uniform light spot, characterized in that: The device comprises a first lens, a second lens, a third lens and an irradiation surface which are sequentially arranged from front to back along an optical axis; The first lens is used to modulate the angle of the incident Gaussian light beam so that the intensity distribution of the modulated light beam on the front surface of the second lens conforms to the morphology of the sinc function along the x-axis and the y-axis; the x-axis and the y-axis are perpendicular to each other and to the optical axis; The second lens is used to change the refraction angle of the light incident on the second lens so that the light is converted back into parallel light for outgoing emission; The third lens is a focusing lens and is used to focus the output light of the second lens on the irradiation surface to form a micron-level square uniform light spot; The front surface of the first lens is a plane, and the rear surface is a curved surface, and the rear surface of the first lens is used to modulate the angle of the incident Gaussian beam; The front surface of the second lens is a curved surface, and the rear surface is a flat surface. The front surface of the second lens is used to change the refraction angle of the light incident on the second lens, so that the light is converted back into parallel light for emission.

2. The beam shaping device for obtaining a micron-level square uniform light spot according to claim 1, characterized in that: The third lens is a biconvex spherical lens or a plano-convex spherical lens.

3. The beam shaping device for obtaining a micron-level square uniform light spot according to claim 1, characterized in that: The two-dimensional sag of the topography of the rear surface of the first lens and the two-dimensional sag of the topography of the front surface of the second lens satisfy the following relationship: ； ； ； ； ； ； in, and are the plane position coordinates of the points on the back surface of the first lens and the front surface of the second lens passed by the same light, is the x-axis coordinate, is the y-axis coordinate, The back surface of the first lens corresponds to The two-dimensional vector height of the position, The front surface of the second lens corresponds to The two-dimensional vector height of the position, The back surface of the first lens corresponds to The one-dimensional vector height of the position, The back surface of the first lens corresponds to The one-dimensional vector height of the position, The front surface of the second lens corresponds to The one-dimensional vector height of the position, The front surface of the second lens corresponds to The one-dimensional vector height of the position, is the refractive index of the first lens for the incident Gaussian beam, is the refractive index of the second lens for the incident Gaussian beam, s is the distance between the back surface of the first lens and the front surface of the second lens, is the coordinate of the turning point of the light in the x-axis direction, The coordinates of the turning point of the light in the y-axis direction.

4. The beam shaping device for obtaining a micron-level square uniform light spot according to claim 3, characterized in that: and The following relationship is satisfied: ； ； in, is the waist radius of the incident Gaussian beam, The maximum light intensity of the sinc function corresponding to the x-axis direction on the front surface of the second lens is: is the maximum light intensity of the sinc function corresponding to the y-axis direction on the front surface of the second lens, is the radius of the clear aperture of the outgoing light beam on the rear surface of the second lens in the x-axis direction, is the radius of the clear aperture of the outgoing light beam from the rear surface of the second lens in the y-axis direction.

5. The beam shaping device for obtaining a micron-level square uniform light spot according to claim 4, characterized in that: The distance between the irradiation surface and the third lens is adjustable.

6. The beam shaping device for obtaining a micron-level square uniform light spot according to claim 4, characterized in that: The area where the light intensity of the micron-sized square uniform light spot is not less than 30% of the maximum light intensity of the micron-sized square uniform light spot is recorded as the effective light spot area, and the size of the effective light spot area meets the following conditions: ； ； in, is the size of the effective spot area in the x-axis direction, is the size of the effective spot area in the y-axis direction, is the wavelength of the incident Gaussian beam, is the focal length of the third lens, is the deviation distance between the illumination surface and the focal plane of the third lens.

7. A laser device comprising a laser and a beam shaping device, characterized in that: The beam shaping device is the beam shaping device for obtaining a micron-level square uniform light spot according to any one of claims 1 to 6, the laser is used to emit a Gaussian beam to the beam shaping device, and the beam shaping device is used to shape the Gaussian beam into a micron-level square uniform light spot.

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