Optical spot distortion correction method of optical system, optical system, device and electronic equipment

Abstract

The application relates to the technical field of lasers, and discloses a spot distortion correction method of an optical system, the optical system, a device and electronic equipment, wherein the optical system comprises a laser, an optical fiber and a collimating lens; the optical fiber is a rectangular optical fiber with a rectangular core layer or a barrel-shaped optical fiber with a barrel-shaped core layer; the method comprises the following steps: determining a residual divergence angle of laser after the laser passes through the collimating lens according to the size of a first spot and an imaging distance; determining a focal length of the collimating lens according to the residual divergence angle and the side length of the core layer; determining whether the optical fiber is the barrel-shaped optical fiber according to the ratio of the focal length to the side length of the core layer; the core layer of the barrel-shaped optical fiber is composed of a plurality of circular arcs; and in the case that the optical fiber is the barrel-shaped optical fiber, the radius of curvature corresponding to each circular arc in the plurality of circular arcs is determined according to the focal length and the side length of the core layer. According to the application, a rectangular homogenized spot without distortion can be obtained under a large divergence angle.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lasers, in particular to a spot distortion correction method of an optical system, an optical system, a device and an electronic equipment. BACKGROUND

[0002] In the fields of laser display, illumination, material processing, etc., the application of rectangular homogenized light spots is more and more widely, and the requirement for the divergence angle of the light spot is also higher and higher. When the divergence angle of the rectangular homogenized light spot is large (for example, the divergence half-angle is greater than 7°), the light rays are relatively divergent in the propagation process, and when received at the same distance, the light spot size is large and the coverage range is wide. However, with the increase of the divergence angle, the optical distortion also increases, which will have a bad influence on the shape and uniformity of the light spot.

[0003] In the related art, a special lens is arranged at the outer end of the light spot shaping element along the propagation direction of the square light spot, the special lens is composed of a middle part, a waist part and an edge position, the curvatures of the middle part, the waist part and the edge position are different; then the change of the optical path difference of the square light spot passing through different positions of the special lens is calculated, the position of the square light spot passing through the special lens is controlled, and based on the change of the optical path difference of different positions, the curvatures of the middle part, the waist part and the edge position are dynamically adjusted to compensate for the optical path difference of different positions, so as to weaken the light spot distortion. However, the above-mentioned method not only needs to be shaped by the light spot shaping element when improving the light spot distortion of large divergence angle, but also needs to calculate the optical path difference at different light spot positions, and the process is relatively complex. SUMMARY

[0004] The present application provides a light spot distortion correction method of an optical system, an optical system, a device and an electronic equipment to solve the problem of light spot distortion when the divergence angle is large.

[0005] In a first aspect, the present application provides a light spot distortion correction method of an optical system, the optical system comprising a laser, an optical fiber and a collimating lens, the optical fiber being a rectangular optical fiber with a rectangular core layer or a barrel-shaped optical fiber with a barrel-shaped core layer, laser generated laser light passing through the optical fiber and the collimating lens in turn, and the laser light emitted from the collimating lens forming a light spot on a receiving screen, the method comprising: determining the remaining divergence angle of the laser after passing through the collimating lens according to the size of the first light spot and the imaging distance, wherein the first light spot is a rectangular light spot required to be presented on the receiving screen; determining the focal length of the collimating lens according to the remaining divergence angle and the side length of the core layer; determining whether the optical fiber is a barrel-shaped optical fiber according to the ratio of the focal length to the side length of the core layer, wherein the core layer of the barrel-shaped optical fiber is composed of a plurality of circular arcs; and in the case that the optical fiber is a barrel-shaped optical fiber, determining the curvature radius corresponding to each circular arc in the plurality of circular arcs according to the focal length and the side length of the core layer, so as to correct the light spot distortion.

[0006] In this embodiment, when increasing the laser divergence angle, the ratio of focal length to the side length of the core layer allows for determination of whether the light spot presented on the receiving screen exhibits distortion before the optical system is constructed. If distortion exists, a barrel-shaped fiber is used to homogenize the laser, correcting the light spot distortion. If no distortion exists, a rectangular fiber is still used to homogenize the laser, ensuring uniformity over a larger divergence angle range (e.g., ...). Within this range, the constructed optical system can consistently produce a distortion-free rectangular homogenized light spot. The barrel-shaped fiber with a specific radius of curvature of this invention can correct distortion while shaping the beam, eliminating the need for other structures to assist in distortion correction and simplifying the final optical system structure.

[0007] In one optional implementation, determining whether to define the optical fiber as a barrel fiber based on the ratio of focal length to the side length of the core layer includes: if the ratio of focal length to the side length of the core layer is greater than or equal to a preset ratio, then the optical fiber is defined as a rectangular optical fiber; if the ratio of focal length to the side length of the core layer is less than the preset ratio, then the optical fiber is defined as a barrel fiber.

[0008] In one optional implementation, before determining whether to define the optical fiber as a barrel fiber, the method further includes: determining the ratio of the focal length to the side length of the core layer when the distortion ratio of the second light spot is first greater than or equal to 1% as a preset ratio, wherein the second light spot is the light spot presented on the receiving screen when the optical fiber is a rectangular optical fiber, and the distortion ratio is the ratio of the difference between the edge vertical height and the center vertical height of the second light spot to the center vertical height.

[0009] In one optional implementation, determining the radius of curvature for each of the plurality of arcs based on the focal length and the edge length of the core layer includes: determining the radius of curvature based on the focal length and the edge length of the core layer using the following formula:

[0010]

[0011] In the formula, Indicates the radius of curvature. Indicates the side length of the core layer. Indicates focal length.

[0012] In this embodiment, the radius of curvature of each arc in multiple arcs is determined by formula based on the focal length and the side length of the core layer, which can better control the spot distortion and make ΔH / 2H < 1%.

[0013] In one optional implementation, 1.2mm ≤ f ≤ 2mm, 50um ≤ d ≤ 2000um. , This represents the remaining divergence angle.

[0014] In an optional embodiment, the method further comprises: determining the distance between the collimating lens and the receiving screen according to the Rayleigh range, wherein the distance between the collimating lens and the receiving screen is greater than 10 times the Rayleigh range.

[0015] The embodiment controls the distance between the collimating lens and the receiving screen to be greater than 10 times the Rayleigh range, and can make the light spot form a near-field distribution, and in this case, the near-field image of the fiber end face can be received, and the uniformity of the light spot is greater than or equal to 85%.

[0016] In a second aspect, the present application provides an optical system, comprising a laser, a fiber and a collimating lens; the fiber is a rectangular fiber with a rectangular core or a barrel-shaped fiber with a barrel-shaped core, and the laser generates laser light which passes through the fiber and the collimating lens in sequence, and the laser light emitted from the collimating lens forms a light spot on a receiving screen; the distance between the fiber end face and the collimating lens is the focal length of the collimating lens, and the focal length of the collimating lens, the shape and size of the core are determined based on the light spot distortion correction method of the optical system of the first aspect or any of the corresponding embodiments thereof.

[0017] In an optional embodiment, the collimating lens comprises a spherical lens, an aspherical lens or a lens group.

[0018] In a third aspect, the present application provides a light spot distortion correction device of an optical system, the optical system comprising a laser, a fiber and a collimating lens, the fiber being a rectangular fiber with a rectangular core or a barrel-shaped fiber with a barrel-shaped core, and the laser generating laser light which passes through the fiber and the collimating lens in sequence, and the laser light emitted from the collimating lens forming a light spot on a receiving screen, the device comprising: a divergence angle determination module configured to determine the remaining divergence angle of the laser light after passing through the collimating lens based on the size of a first light spot and the imaging distance, wherein the first light spot is a rectangular light spot required to be presented on the receiving screen; a focal length determination module configured to determine the focal length of the collimating lens based on the remaining divergence angle and the side length of the core; a fiber selection module configured to determine whether the fiber is a barrel-shaped fiber based on the ratio of the focal length to the side length of the core, wherein the core of the barrel-shaped fiber is composed of a plurality of circular arcs; and a curvature radius determination module configured to determine the curvature radius corresponding to each circular arc in the plurality of circular arcs based on the focal length and the side length of the core in the case that the fiber is a barrel-shaped fiber, so as to correct the light spot distortion.

[0019] In a fourth aspect, the present application provides an electronic device, comprising a memory and a processor, the memory and the processor being in communication connection with each other, and the memory storing computer instructions, and the processor executing the computer instructions to perform the light spot distortion correction method of the optical system of the first aspect or any of the corresponding embodiments thereof. BRIEF DESCRIPTION OF DRAWINGS

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of an optical system according to an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the structure of a rectangular optical fiber according to an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the structure of a barrel-shaped optical fiber according to an embodiment of the present invention;

[0024] Figure 4 This is a schematic flowchart of a method for correcting the spot distortion of an optical system according to an embodiment of the present invention;

[0025] Figure 5 This is a schematic diagram of spot distortion according to an embodiment of the present invention;

[0026] Figure 6 This is a schematic diagram of the light spot after homogenization using a square optical fiber according to an embodiment of the present invention;

[0027] Figure 7 This is a schematic diagram of the light spot after homogenization using a barrel-shaped optical fiber according to an embodiment of the present invention;

[0028] Figure 8 This is a schematic flowchart of another method for correcting the spot distortion of an optical system according to an embodiment of the present invention;

[0029] Figure 9 This is a schematic diagram of the structure of another optical system according to an embodiment of the present invention;

[0030] Figure 10 This is a schematic flowchart of another method for correcting the spot distortion of an optical system according to an embodiment of the present invention;

[0031] Figure 11 This is a structural block diagram of a spot distortion correction device for an optical system according to an embodiment of the present invention;

[0032] Figure 12 This is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present invention.

[0033] Reference numerals: 10, laser; 20, optical fiber; 21, core layer; 22, cladding layer; 23, coating layer; 30, collimating lens; 40, receiving screen. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0036] Rectangular uniform light spots are widely used in laser display, lighting and materials processing. For example, in the field of laser display, rectangular uniform light spots can be adapted to the rectangular screen of the display panel and can make the display screen have uniform brightness and clear edges, thus improving the display effect.

[0037] Currently, rectangular spot shaping methods include diffractive optical elements (DOE) methods, microlens array methods, Powell prism stacking, and fiber bundle homogenization methods. However, the rectangular homogenized spots obtained by these optical shaping elements usually have a small divergence angle. When the divergence angle is increased, the optical distortion also increases, which will have a detrimental effect on the shape and uniformity of the spot.

[0038] In view of this, the present invention provides a method, optical system, device and electronic device for correcting the beam distortion of an optical system. When designing the optical system, by using the ratio of the focal length of the collimating lens to the core diameter of the optical fiber, the laser can be homogenized by a barrel fiber when the beam distortion is caused by the increase of the divergence angle. Thus, even at large divergence angles (e.g., a divergence half angle greater than or equal to 7°), a distortion-free rectangular homogenized beam spot can be obtained.

[0039] To facilitate understanding of the present invention, the optical system of the present invention will first be briefly described in conjunction with the accompanying drawings.

[0040] like Figure 1 As shown, the optical system provided by the present invention includes a laser 10, an optical fiber 20, and a collimating lens 30.

[0041] The laser beam emitted from laser 10 is coupled into optical fiber 20, which homogenizes the laser beam. Collimating lens 30 is located on the output side of optical fiber 20 and is used to convert the divergent light output from optical fiber 20 into parallel light. Receiving screen 40 is located on the output side of collimating lens 30, and the light output from collimating lens 30 forms a light spot on receiving screen 40. That is, the laser beam generated by laser 10 passes through optical fiber 20 and collimating lens 30 in sequence before forming a light spot on receiving screen 40.

[0042] like Figure 2 and Figure 3 As shown, the optical fiber 20 includes a core layer 21, a cladding layer 22, and a coating layer 23 surrounding the cladding layer 22. The cladding layer 22 surrounds the core layer 21, and the refractive index of the cladding layer 22 is less than that of the core layer 21. The cladding layer 22 confines the laser emitted by the laser 10 to propagate within the core layer 21 through total internal reflection. The optical fiber 20 provided by this invention can be as follows: Figure 2 The optical fiber shown has a rectangular core, or as shown in the image. Figure 3 The image shows a barrel-shaped optical fiber with a barrel-shaped core.

[0043] The numerical aperture (NA) of an optical fiber ranges from 0.05 to 0.5. For example, the NA of an optical fiber can be 0.05, 0.1, 0.2, 0.4, or 0.5. NA is a key parameter characterizing the light-guiding properties of an optical fiber. It is determined by the refractive index of the fiber core and the optical cladding, and describes the fiber's ability to receive incident / outgoing light or the range of its divergence angle. The larger the value, the wider the angle of light the fiber can receive (the stronger the light-receiving ability), and the larger the divergence angle of the outgoing light.

[0044] According to an embodiment of the present invention, an embodiment of a method for correcting spot distortion in an optical system is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in an electronic device such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0045] This embodiment provides a method for correcting the beam distortion of an optical system, which can be used in electronic devices such as mobile phones, tablets, and computers. Figure 4 This is a flowchart of a method for correcting the spot distortion of an optical system according to an embodiment of the present invention, such as... Figure 4 As shown, the process includes the following steps:

[0046] Step S401: Determine the remaining divergence angle of the laser after passing through the collimating lens based on the size of the first light spot and the imaging distance.

[0047] The first light spot is the rectangular light spot that the receiving screen needs to display. The size of the first light spot can refer to the side length of the first light spot. The imaging distance refers to the straight-line distance between the light-emitting surface of the collimating lens 30 and the imaging surface of the receiving screen 40.

[0048] Specifically, after obtaining the side length of the first spot and the imaging distance, the remaining divergence angle can be determined by the following formula (1).

[0049]

[0050] In equation (1), Indicates the remaining divergence angle. This represents the side length of the first light spot. Indicates the imaging distance.

[0051] The side lengths of the first light spot may not be equal, and each side of the first light spot with a different length corresponds to a residual divergence angle. For example, when the shape of the first light spot is rectangular, the side length of the first light spot includes the length of the longest side. and the length of the shorter side At this point, the remaining divergence angle includes the remaining divergence angle of the longer side. and the remaining divergence angle of the short side .

[0052] Taking a square homogenized light spot with equal side lengths as an example, if the side length of the first light spot is 166.67 mm and the imaging distance is 500 mm, then the remaining divergence angle of the laser after passing through the collimating lens is... .

[0053] Step S402: Determine the focal length of the collimating lens based on the remaining divergence angle and the side length of the core layer.

[0054] Specifically, the side lengths of the different sides of the core layer may be different, for example, as... Figure 2 and Figure 3 As shown, the side length d of the core layer can include the long side length d1 and the short side length d2. The side length of the core layer can be determined based on the output power and fiber manufacturing process. The fiber manufacturing process determines the range of values ​​for the side length of the core layer. The side length of the core layer is positively correlated with the output power; that is, the higher the output power, the longer the side length of the core layer. After determining the output power, a value can be selected from the range of values ​​for the side length of the core layer based on the output power.

[0055] After determining the side length of the core layer, the focal length of the collimating lens can be determined using the following formula (2):

[0056]

[0057] In equation (2), Indicates the laser beam waist radius. This indicates the focal length of the collimating lens. The waist of the homogenized beam output from the optical fiber is located at the fiber end face, i.e. Equal to the side length d of the core layer, d and They check and balance each other.

[0058] For example, if the first light spot is a square homogenized light spot with d=500um, the remaining divergence angle is... Based on formula (2), the focal length of the collimating lens can be determined to be 1.5 mm. During the calculation, the remaining divergence angle needs to be converted to radians.

[0059] Step S403: Determine whether to define the optical fiber as a barrel fiber based on the ratio of focal length to the side length of the core layer.

[0060] Specifically, when the ratio of focal length to core length is large (greater than or equal to a preset ratio), the divergence angle is relatively small. In this case, using a rectangular fiber as input results in an imaging spot with the same rectangular cross-sectional shape as the core. Rectangular fibers are then used for laser homogenization. However, as the ratio of the collimating lens's focal length (f) to the fiber core diameter (core length d) decreases (below the preset ratio), the divergence angle increases, and distortion gradually occurs at the edges of the imaging spot, causing the spot to deform. When using a rectangular fiber as input, the imaging spot is no longer rectangular. In this case, a barrel-shaped fiber is needed for laser homogenization.

[0061] Whether the light spot displayed on the receiving screen is distorted can be determined by... Determined, among which, such as Figure 5 As shown, This represents the difference between the vertical height of the imaging spot's edge and its center. Indicates the vertical height of the center. When... When there is no distortion in the light spot; when At this time, the light spot is distorted, affecting the imaging effect. The preset ratio can be the distortion ratio of the second light spot. The ratio of focal length to core layer side length when the first value is greater than or equal to 1%, for example, a preset value of 6, etc. The second light spot is the light spot presented on the receiving screen when the optical fiber is a rectangular fiber.

[0062] Specifically, as the ratio of the lens focal length to the side length of the core layer decreases, As the lens grows larger, distortion begins to appear in the second light spot. At the precise moment when distortion first appears in the second light spot, the ratio of the lens focal length to the edge length of the core layer is a preset value. The exact moment when distortion first appears in the second light spot refers to the distortion ratio of the second light spot. The moment when it first exceeds or equals 1%, that is... The moment when it changes from <1% to ≥1%.

[0063] The core of a barrel-shaped optical fiber is composed of multiple circular arcs. For example... Figure 3As shown, the barrel-shaped optical fiber consists of four arcs with a radius of curvature of R. The radii of curvature of two opposite arcs are equal, and the radius of curvature of the longer arc is... The radius of curvature of the shorter side arc is .

[0064] Step S404: Based on the focal length and the side length of the core layer, determine the radius of curvature of each of the multiple arcs to correct the spot distortion.

[0065] Specifically, there is a corresponding relationship between the focal length, the side length of the core layer, and the radius of curvature. After determining the focal length and the side length of the core layer, the radius of curvature corresponding to each arc can be determined through the corresponding relationship. This corresponding relationship can be derived through geometric optics and aberration compensation theory. By designing the curvature of the arc to correct distortion, the imaging spot is ensured to be a rectangular spot.

[0066] The side length of the core layer includes the length of the long side d1 and the length of the short side d2, and the radius of curvature of the multiple arcs includes the radius of curvature of the long side arc. and the radius of curvature of the shorter side arc At that time, the radius of curvature of the arc on the long side is obtained based on the length d1 of the long side, the focal length, and the corresponding relationship. The radius of curvature of the short side arc is obtained based on the short side length d2, focal length, and corresponding relationships. .

[0067] When the divergence angle increases to a certain extent, if a rectangular optical fiber is used, the shape and size of the light spot appearing on the receiving screen may be as follows: Figure 6 As shown, if the rectangular optical fiber is adjusted to a barrel-shaped optical fiber, the shape and size of the light spot appearing on the receiving screen will be as follows. Figure 7 As shown. Figure 6 and Figure 7 The horizontal axis represents the size of the light spot in the horizontal direction X, in millimeters. Figure 6 and Figure 7 The vertical axis represents the size of the light spot in the vertical direction Y, in millimeters.

[0068] The uniformity of the light spot presented on the receiving screen can be determined by the following formula (3):

[0069]

[0070] In formula (3), Indicates the uniformity of the light spot. This represents the maximum light intensity of all pixels within the selected light spot area. This represents the average light intensity of all pixels within the selected light spot area. In this embodiment, formula (3) yields a light spot uniformity of ≥85% for the rectangular light spot at the working surface of the receiving screen of the optical system designed in this invention.

[0071] The optical system spot distortion correction method provided in this embodiment first determines the residual divergence angle of the laser after passing through the collimating lens based on the size of the first spot and the imaging distance. Then, based on the residual divergence angle and the side length of the core layer, the focal length of the collimating lens is determined. Based on the ratio of the focal length to the side length of the core layer, it is determined whether the shape of the core layer is barrel-shaped. Based on the focal length and the side length of the core layer, the radius of curvature of each of the multiple arcs constituting the barrel shape is determined.

[0072] In this embodiment, when increasing the laser divergence angle, the ratio of focal length to the side length of the core layer allows for determination of whether the light spot presented on the receiving screen exhibits distortion before the optical system is constructed. If distortion exists, a barrel-shaped fiber is used to homogenize the laser, correcting the light spot distortion. If no distortion exists, a rectangular fiber is still used to homogenize the laser, ensuring uniformity over a larger divergence angle range (e.g., ...). Within this range, the constructed optical system can consistently produce a distortion-free rectangular homogenized light spot. The barrel-shaped fiber with a specific radius of curvature of this invention can correct distortion while shaping the beam, eliminating the need for other structures to assist in distortion correction and simplifying the final optical system structure.

[0073] This embodiment also provides another method for correcting the spot distortion of an optical system, which can be used in electronic devices. Figure 8 This is a flowchart of another method for correcting spot distortion in an optical system according to an embodiment of the present invention, such as... Figure 8 As shown, the process includes the following steps:

[0074] Step S801: Determine the remaining divergence angle of the laser after passing through the collimating lens based on the size of the first light spot and the imaging distance.

[0075] Please see details Figure 4 Step S401 of the illustrated embodiment will not be described again here.

[0076] Step S802: Determine the focal length of the collimating lens based on the remaining divergence angle and the side length of the core layer.

[0077] Please see details Figure 4 Step S402 of the illustrated embodiment will not be described again here.

[0078] Step S803: Determine whether to define the optical fiber as a barrel fiber based on the ratio of focal length to the side length of the core layer.

[0079] For example, step S803 above includes:

[0080] Step S8031: If the ratio of focal length to the side length of the core layer is greater than or equal to a preset ratio, the optical fiber is determined to be a rectangular optical fiber.

[0081] In step S8032, if the ratio of focal length to the side length of the core layer is less than a preset ratio, the optical fiber is determined to be a barrel fiber.

[0082] Among them, the distortion ratio of the second spot ( When the first value is greater than or equal to 1%, the ratio of the focal length to the side length of the core layer is determined as the preset ratio. The second spot is the spot that appears on the receiving screen when the optical fiber is a rectangular optical fiber.

[0083] Specifically, the side length d of the core layer can include the length of the longer side d1 and the length of the shorter side d2. In this case, the ratio of the focal length to the side length of the core layer includes the ratio of the longer side. Ratio of the shorter side When the ratio of the longer sides or the ratio of the shorter sides When the ratio is less than a preset value, it is determined that the second light spot has distortion, and the optical fiber is identified as a barrel fiber; when the ratio of the long side is less than a preset value, it is determined that the second light spot has distortion. Ratio of the shorter side When all values ​​are greater than or equal to the preset ratio, it is determined that there is no distortion in the second light spot, and the optical fiber is determined to be a rectangular optical fiber.

[0084] Step S804: Based on the focal length and the side length of the core layer, determine the radius of curvature of each of the multiple arcs using the following formula (4).

[0085]

[0086] In equation (4), Indicates the radius of curvature. Indicates the side length of the core layer. This represents the focal length. When d = d1, When d=d2, For example, if the first spot is a square homogenized spot with d=500um and f=1.5mm, then based on formula (4), the radius of curvature R=1.9mm can be determined to complete the modeling of the barrel fiber.

[0087] Where 1.2mm≤f≤2mm, 50um≤d≤2000um, when the collimating lens has a focal length f≥1.2mm and d=2000um, the residual divergence angle of the laser satisfies: The present invention can obtain a rectangular homogenized light spot with a maximum divergence angle of 47.75°.

[0088] Step S805: Determine the distance between the collimating lens and the receiving screen based on the Rayleigh interval.

[0089] Among them, the distance between the collimating lens and the receiving screen is greater than 10 times the Rayleigh interval.

[0090] Specifically, such asFigure 9 As shown, the distance between the fiber end face and the collimating lens is equal to the focal length f of the collimating lens, and the Rayleigh interval behind the collimating lens is... It can be determined using formula (5):

[0091]

[0092] In the formula, The beam quality factor. For the laser wavelength, the distance between the collimating lens and the working surface of the receiving screen is greater than 10 times the Rayleigh range. At this time, a near-field image of the fiber end face is formed at the working surface.

[0093] In this embodiment, the radius of curvature of each arc in multiple arcs is determined by the following formula (4) based on the focal length and the side length of the core layer. This can better control the beam distortion and make ΔH / 2H < 1%. By controlling the distance between the collimating lens and the receiving screen to more than 10 times the Rayleigh interval, the beam can be distributed in the near field. At this time, the near field image of the fiber end face can be received, and the beam uniformity is greater than or equal to 85%.

[0094] The following detailed description of the construction process of the optical system provided by the present invention, with reference to the accompanying drawings and taking a rectangular light spot as an example with a preset ratio of 6, will be provided.

[0095] like Figure 10 As shown, firstly, based on the required rectangular spot size and imaging distance, the residual divergence angle of the laser after passing through the collimating lens is calculated. Specifically, the remaining divergence angle It can be divided into and Then according to the formula Matching fiber core diameter , And the required focal length f of the collimating lens, and calculate the ratio respectively. and Then, determine the ratio. and Is it less than 6, when or When the value is less than 6, a barrel-shaped fiber is selected for homogenization. The long side radius of curvature and the short side radius of curvature of the barrel-shaped fiber both satisfy the following:

[0096]

[0097] Where 1.2mm≤f≤2mm, 50um≤d≤2000um. When and When all values ​​are greater than or equal to 6, rectangular optical fibers are used for homogenization. Finally, spherical or aspherical lenses are selected based on the required focal length f of the collimating lens to complete the optical system design.

[0098] Specifically, if the first light spot is a square homogenized light spot with a side length of 166.67 mm, and the distance between the collimating lens and the receiving screen is 500 mm, then the required residual laser divergence angle is... It is 9.55°. According to the formula... The matching fiber core diameter d and the collimating lens focal length f can be d = 500 μm and f = 1.5 mm, respectively. Based on the ratio f / d = 3 < 6, a barrel-shaped fiber is selected for homogenization. The radius of curvature of each side of the barrel-shaped fiber satisfies the formula:

[0099]

[0100] Where 1.2mm≤f≤2mm, 200um≤d≤500um. Based on the formula, the radius of curvature R = 1.9mm can be calculated, completing the modeling of the barrel-shaped fiber. Subsequently, by continuously adjusting the lens radius of curvature and conic coefficient, an aspherical lens with a focal length f of 1.5mm is obtained, completing the optical system design. A square homogenized light spot with a side length of 166.67mm is obtained at a distance of 500mm. At this point, the optical distortion ΔH / 2H < 1%, and the light spot uniformity > 85%.

[0101] If a square light spot is used for homogenization, and the simulation is performed using the aforementioned f1.5mm aspherical lens, the resulting light spot will be distorted, with the vertical height at the edge of the light spot being greater than the vertical height at the center. The distortion ΔH / 2H = 4.58% > 1%. Therefore, using a barrel-shaped fiber for homogenization has achieved a significant effect.

[0102] The present invention also provides an optical system, such as Figure 9 As shown, the optical system includes a laser 10, an optical fiber 20, and a collimating lens 30.

[0103] The optical fiber is a rectangular optical fiber with a rectangular core or a barrel-shaped optical fiber with a barrel-shaped core. The laser generated by the laser passes through the optical fiber and the collimating lens in sequence. The laser emitted from the collimating lens forms a light spot on the receiving screen. The distance between the light-emitting surface of the optical fiber and the collimating lens is the focal length f of the collimating lens. The focal length, core shape and size of the collimating lens are determined based on the light spot distortion correction method of the optical system provided in any of the above embodiments.

[0104] For example, a collimating lens includes a spherical lens, an aspherical lens, or a lens group. Lasers include, but are not limited to, semiconductor lasers, whose output beams have a Gaussian or super-Gaussian distribution along the fast and slow axes.

[0105] Optionally, the optical fiber is a barrel fiber with NA0.22, and the distance between the collimating lens and the working surface is greater than 10 times the Rayleigh interval.

[0106] The laser provided in this embodiment is a semiconductor laser. The laser emitted by the chip is coupled into an optical fiber for transmission. After being homogenized by the fiber, a homogenized spot with the same shape as the fiber end face is obtained at the fiber end face, with a spot homogenization degree >85%. The laser output from the optical fiber is transformed by a collimating lens and then focused at the beam waist behind the collimating lens. The beam distribution changes to a far-field distribution, at which point it exhibits a super-Gaussian shape. When the beam propagates to the waist... and 10 times Rayleigh range Between these distances, the light spot exhibits a near-field and far-field mixed state; when the transmission distance exceeds 10 times the Rayleigh interval... Afterwards, the light spot is distributed in the near field, and at this time the near field image of the fiber end face can be received, with a light spot homogenization of >85%.

[0107] The optical system provided by this invention can obtain a divergence angle. satisfy The homogenized beam has a wide divergence angle coverage, thus the optical system has a wide range of applications. The obtained homogenized beam is rectangular, with distortion ΔH / 2H < 1% and beam uniformity ≥ 85%. The optical system provided by this invention can correct distortion while shaping the beam using a barrel-shaped optical fiber, without the need for other structures to assist in distortion correction. The structure is relatively simple, and a near-field image of the fiber end face can be obtained in the 10 Rayleigh range using only a collimating lens. The simple optical path structure is beneficial to reducing the size of the optical system.

[0108] This embodiment also provides a spot distortion correction device for an optical system, which is used to implement the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0109] This embodiment provides a spot distortion correction device for an optical system, such as... Figure 11 As shown, it includes:

[0110] The divergence angle determination module 1101 is used to determine the remaining divergence angle of the laser after passing through the collimating lens based on the size of the first light spot and the imaging distance, wherein the first light spot is a rectangular light spot that the receiving screen needs to present;

[0111] The focal length determination module 1102 is used to determine the focal length of the collimating lens based on the remaining divergence angle and the side length of the core layer.

[0112] The fiber selection module 1103 is used to determine whether to identify the fiber as a barrel fiber based on the ratio of focal length to the side length of the core layer, wherein the core layer of the barrel fiber is composed of multiple arcs.

[0113] The radius of curvature determination module 1104 is used to determine the radius of curvature of each of the multiple arcs based on the focal length and the side length of the core layer.

[0114] In some alternative implementations, the fiber selection module 1103 includes:

[0115] The first selection unit is used to determine the optical fiber as a rectangular optical fiber if the ratio of the focal length to the side length of the core layer is greater than or equal to a preset ratio.

[0116] The second selection unit is used to determine the optical fiber as a barrel fiber if the ratio of the focal length to the side length of the core layer is less than a preset ratio.

[0117] In some alternative embodiments, the apparatus further includes:

[0118] The ratio determination module is used to determine the ratio of the focal length to the side length of the core layer when the distortion ratio of the second light spot is first greater than or equal to 1% as the preset ratio, wherein the second light spot is the light spot presented on the receiving screen when the optical fiber is a rectangular optical fiber, and the distortion ratio is the ratio of the difference between the edge vertical height and the center vertical height of the second light spot to the center vertical height.

[0119] In some alternative implementations, the radius of curvature determination module 1104 includes:

[0120] The first determining unit is used to determine the radius of curvature based on the focal length and the edge length of the core layer using the following formula:

[0121]

[0122] In the formula, Indicates the radius of curvature. Indicates the side length of the core layer. Indicates focal length.

[0123] In some alternative implementations, 1.2mm ≤ f ≤ 2mm, 50um ≤ d ≤ 2000um. , This represents the remaining divergence angle.

[0124] In some alternative embodiments, the apparatus further includes:

[0125] The distance determination module is used to determine the distance between the collimating lens and the receiving screen based on the Rayleigh interval, wherein the distance between the collimating lens and the receiving screen is greater than 10 times the Rayleigh interval.

[0126] The optical system spot distortion correction device provided in this embodiment of the invention can execute the optical system spot distortion correction method provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects for executing the method. Further functional descriptions of the above modules and units are the same as in the corresponding embodiments described above, and will not be repeated here.

[0127] Figure 12 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention.

[0128] The following is a detailed reference. Figure 12 The diagram illustrates a structural schematic suitable for implementing an electronic device according to embodiments of the present invention. The electronic device may include a processor (e.g., a central processing unit, graphics processor, etc.) 1201, which can perform various appropriate actions and processes according to a program stored in read-only memory (ROM) 1202 or a program loaded from memory 1208 into random access memory (RAM) 1203. The RAM 1203 also stores various programs and data required for the operation of the electronic device. The processor 1201, ROM 1202, and RAM 1203 are interconnected via a bus 1204. An input / output (I / O) interface 1205 is also connected to the bus 1204.

[0129] Typically, the following devices can be connected to I / O interface 1205: input devices 1206 including, for example, touchscreens, touchpads, keyboards, mice, cameras, microphones, accelerometers, gyroscopes, etc.; output devices 1207 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; memory devices 1208 including, for example, magnetic tapes, hard disks, etc.; and communication devices 1209. Communication device 1209 allows electronic devices to communicate wirelessly or wiredly with other devices to exchange data. Although Figure 12 Electronic devices with various devices are shown, but it should be understood that it is not required to implement or have all of the devices shown, and more or fewer devices may be implemented or have instead.

[0130] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program carried on a non-transitory computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device 1209, or installed from a memory 1208, or installed from a ROM 1202. When the computer program is executed by the processor 1201, it performs the functions defined in the spot distortion correction method of the optical system according to embodiments of the present invention.

[0131] Figure 12 The electronic device shown is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments of the present invention.

[0132] This invention also provides a computer-readable storage medium. The methods described above according to embodiments of the invention can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded via a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code. When the software or computer code is accessed and executed by the computer, processor, or hardware, the spot distortion correction method of the optical system shown in the above embodiments is implemented.

[0133] A portion of this invention can be applied to computer program products, such as computer program instructions, which, when executed by a computer, can invoke or provide the methods and / or technical solutions according to the invention through the operation of the computer. Those skilled in the art will understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executing the instructions, or the computer compiling the instructions and then executing the corresponding compiled program, or the computer reading and executing the instructions, or the computer reading and installing the instructions and then executing the corresponding installation program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to a computer.

[0134] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for correcting spot distortion in an optical system, characterized in that, The optical system includes a laser, an optical fiber, and a collimating lens. The optical fiber is a rectangular fiber with a rectangular core or a barrel-shaped fiber with a barrel-shaped core. The laser generated by the laser passes sequentially through the optical fiber and the collimating lens. The laser emitted from the collimating lens forms a light spot on a receiving screen. The method includes: Based on the size of the first light spot and the imaging distance, the remaining divergence angle of the laser after passing through the collimating lens is determined, wherein the first light spot is the rectangular light spot that the receiving screen needs to present; The focal length of the collimating lens is determined based on the remaining divergence angle and the side length of the core layer; Based on the ratio of the focal length to the side length of the core layer, it is determined whether the optical fiber is to be classified as a barrel fiber, wherein the core layer of the barrel fiber is composed of multiple arcs; the determination of whether the optical fiber is to be classified as a barrel fiber based on the ratio of the focal length to the side length of the core layer includes: if the ratio of the focal length to the side length of the core layer is greater than or equal to a preset ratio, then the optical fiber is classified as a rectangular fiber; if the ratio of the focal length to the side length of the core layer is less than the preset ratio, then the optical fiber is classified as a barrel fiber. When the optical fiber is the barrel-shaped optical fiber, the radius of curvature of each of the plurality of arcs is determined according to the focal length and the side length of the core layer in order to correct the spot distortion. When the optical fiber is a rectangular optical fiber, the imaging spot has the same shape as the core cross-section of the optical fiber, which is also rectangular.

2. The method according to claim 1, characterized in that, Before determining whether to classify the optical fiber as a barrel fiber, the method further includes: The ratio of focal length to core side length corresponding to the first time the distortion ratio of the second spot is greater than or equal to 1% is determined as the preset ratio, wherein the second spot is the spot presented on the receiving screen when the optical fiber is a rectangular optical fiber, and the distortion ratio is the ratio of the difference between the edge vertical height and the center vertical height of the second spot to the center vertical height.

3. The method according to claim 1 or 2, characterized in that, The step of determining the radius of curvature of each of the plurality of circular arcs based on the focal length and the side length of the core layer includes: The radius of curvature is determined using the following formula based on the focal length and the side length of the core layer: In the formula, This represents the radius of curvature. This indicates the side length of the core layer. This indicates the focal length.

4. The method according to claim 3, characterized in that, 1.2mm≤f≤2mm, 50um≤d≤2000um, , This represents the remaining divergence angle.

5. The method according to claim 1 or 2, characterized in that, The method further includes: The distance between the collimating lens and the receiving screen is determined based on the Rayleigh interval, wherein the distance between the collimating lens and the receiving screen is greater than 10 times the Rayleigh interval.

6. An optical system, characterized in that, Includes lasers, optical fibers, and collimating lenses; The optical fiber is a rectangular optical fiber with a rectangular core or a barrel-shaped optical fiber with a barrel-shaped core. The laser generated by the laser passes through the optical fiber and the collimating lens in sequence, and the laser emitted from the collimating lens forms a light spot on the receiving screen. The distance between the fiber end face and the collimating lens is the focal length of the collimating lens. The focal length of the collimating lens, the shape and size of the core layer are determined based on the spot distortion correction method of the optical system according to any one of claims 1 to 5.

7. The optical system according to claim 6, characterized in that, The collimating lens includes a spherical lens, an aspherical lens, or a lens group.

8. A spot distortion correction device for an optical system, characterized in that, The optical system includes a laser, an optical fiber, and a collimating lens. The optical fiber is a rectangular optical fiber with a rectangular core or a barrel-shaped optical fiber with a barrel-shaped core. The laser generated by the laser passes sequentially through the optical fiber and the collimating lens, and the laser emitted from the collimating lens forms a light spot on the receiving screen. The device includes: The divergence angle determination module is used to determine the remaining divergence angle of the laser after passing through the collimating lens based on the size of the first light spot and the imaging distance, wherein the first light spot is the rectangular light spot that the receiving screen needs to present; A focal length determination module is used to determine the focal length of the collimating lens based on the remaining divergence angle and the side length of the core layer; An optical fiber selection module is used to determine whether to classify the optical fiber as a barrel fiber based on the ratio of the focal length to the side length of the core layer, wherein the core layer of the barrel fiber is composed of multiple arcs; the step of determining whether to classify the optical fiber as a barrel fiber based on the ratio of the focal length to the side length of the core layer includes: if the ratio of the focal length to the side length of the core layer is greater than or equal to a preset ratio, then the optical fiber is classified as a rectangular fiber; if the ratio of the focal length to the side length of the core layer is less than the preset ratio, then the optical fiber is classified as a barrel fiber. The curvature radius determination module is used to determine the curvature radius corresponding to each of the plurality of arcs based on the focal length and the side length of the core layer when the optical fiber is the barrel-shaped optical fiber, so as to correct the spot distortion; when the optical fiber is a rectangular optical fiber, the imaging spot has the same shape as the cross-section of the core layer of the optical fiber, and is also rectangular.

9. An electronic device, characterized in that, include: The system includes a memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor executes the computer instructions to perform the spot distortion correction method of the optical system according to any one of claims 1 to 5.

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