A free-form surface shaping device for beam control of a light source with non-rotationally symmetric light intensity distribution

Abstract

The present invention discloses a free-form surface shaping device for controlling the light beam of a light source with a non-rotationally symmetric light intensity distribution. The present invention belongs to the field of non-imaging optical technology. The present invention sets the system optical path structure according to the lighting requirements, and flexibly controls the light source with a non-rotationally symmetric light intensity distribution by numerically trimming the free-form surface shape. The present invention mainly designs a free-form surface lens that meets the target lighting distribution based on Snell's law and the law of conservation of energy with the assistance of a computer. The present invention can control the non-rotationally symmetric light output distribution of the light source on the vertical axis and the inclined target surface, and can also simultaneously control the output light intensity and wavefront of the non-rotationally symmetric light source. The present invention can use only one free-form surface lens to shape the light output distribution of the light source into a target radiance distribution. The present invention has a simple structure; good shaping effect, high energy utilization rate; strong practicality, and a wide range of applications. The design of the present invention can ensure the continuity of the surface and is easy to process.

Description

Technical Field

[0001] The present invention relates to the field of non-imaging optics and laser lighting technology, and in particular to a free-form surface shaping device for performing light beam control on a light source with a non-rotationally symmetric light intensity distribution. Background Art

[0002] Traditional beam shaping systems are generally designed for light sources with rotationally symmetric emission distributions. However, beam shaping methods for light sources with non-rotationally symmetric emission distributions require further development. Laser diodes are a typical example of light sources with non-rotationally symmetric emission distributions. Laser diodes are widely used in various fields, including lighting, communications, measurement, and sensing, due to their small size, light weight, easy modulation, long life, low power consumption, and high efficiency. However, due to their emission principle, laser diode beams have different divergence angles perpendicular to and parallel to the PN junction, resulting in an elliptical light spot distribution. This necessitates beam shaping for laser diode applications. Currently, laser diode beam shaping is primarily achieved through gradient index lenses, reflectors, prisms, and cylindrical lenses. While these approaches have achieved groundbreaking progress in laser diode beam shaping, most of these techniques involve the use of multiple lenses to shape the fast and slow axes of the laser diode separately to achieve the desired beam distribution. This combination of lenses increases system complexity and also results in energy loss due to light reflections between multiple mirrors, hindering the miniaturization of the shaping system. At the same time, existing laser diode shaping lenses are designed for vertical target surfaces and are not suitable for non-vertical target surfaces, which have a wider range of applications. Furthermore, depending on the application of laser diodes, the shaped beam needs to be coupled with other optical systems, which means it is necessary to develop a lens that can simultaneously control the intensity and phase distribution of the laser diode beam.

[0003] Optical freeform surfaces are a type of optical surfaces that do not have axial rotational symmetry or translational symmetry. Their flexible surface structure can break through the concept of traditional optical systems and create new structural forms. They can greatly simplify the system structure and reduce the number of optical components while effectively improving system performance, and can realize lightweight and small beam control systems with high performance and new functions. They have important application value in cutting-edge defense and civilian fields such as high-efficiency energy-saving lighting and laser beam shaping. Freeform surface non-imaging beam control technology has become one of the important development directions in the current field of optical engineering. Applying freeform surface beam shaping technology to the beam shaping of non-rotationally symmetric light sources will result in more compact, lightweight, and energy-efficient beam shaping lenses. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of existing shaping technologies for non-rotationally symmetric light sources and to provide a free-form surface shaping device for light beam control of a light source with a non-rotationally symmetric light intensity distribution. The present invention uses a free-form surface lens to shape the non-rotationally symmetric light output distribution into a predetermined illumination distribution on any target surface in three-dimensional space. At the same time, the lens can simultaneously control the light intensity and wavefront distribution of the light emitted by the light source.

[0005] The present invention provides a free-form surface shaping device for controlling a light beam of a light source having a non-rotationally symmetric light intensity distribution. The device comprises a light source (U) having a non-rotationally symmetric light intensity distribution and a free-form surface lens (V); the optical axis of the light source coincides with the optical axis of the free-form surface lens; the free-form surface lens comprises an incident surface (S1) and an exit surface (S2); the incident surface and the exit surface are not rotationally symmetric; the non-rotationally symmetric light intensity distribution and phase distribution emitted by the light source are controlled by the free-form surface lens to generate a predetermined radiant illumination distribution and phase distribution on a predetermined target surface; the free-form surface lens is designed using the following steps:

[0006] (1) A free-form surface lens optical path structure is set, and light emitted by a light source with a non-rotationally symmetric light intensity distribution is beam-shaped by the free-form surface lens to present a specific radiant illumination distribution and phase distribution on the target illumination surface; wherein the target surface in the optical path structure is an arbitrary target plane in three-dimensional space, and the radiant illumination distribution and phase distribution on the target surface are pre-set according to user requirements;

[0007] (2) Determine the luminous distribution of a light source whose luminous intensity does not have rotational symmetry and determine the far-field divergence angle θ of its fast and slow axes || and θ ⊥ ;

[0008] (3) Determine a virtual light source, wherein the virtual light source has a rotationally symmetric light distribution, and θ initial⊥ =θ initial|| =θ ⊥ ;

[0009] (4) designing an initial structure of a free-form surface lens according to the rotationally symmetric virtual light source described in step (3), wherein the initial structure is an aspherical surface;

[0010] (5) Establish the energy conservation and transformation relationship between the light source and the target illumination in step (3) based on the optimal transport theory and the law of refraction;

[0011] (6) Establishing optical path constraints based on the wavefront of the incident light beam and the wavefront of the target outgoing light beam;

[0012] (7) establishing boundary conditions for achieving the transformation from the incident boundary to the exit boundary based on the non-rotationally symmetric light distribution boundary of the incident light beam and the target light spot boundary;

[0013] (8) Based on the virtual light source in step (3), the aspheric initial structure in step (4) is numerically optimized, and a free-form surface lens that satisfies the illumination distribution is obtained by iterative calculation;

[0014] (9) Reduce the far-field divergence angle of the virtual light source in step (3), i.e., θ initial⊥ Keep it constant and gradually reduce θ initial|| , and perform step (8) to obtain the free-form surface shape based on the updated virtual light source beam control;

[0015] (10) Continue to reduce θ initial|| And proceed to step (9) until θ initial|| =θ || The light distribution of the virtual light source is made consistent with the light distribution of the actual light source, thereby obtaining the free-form surface lens surface data required to realize the light beam control of the light source with non-rotationally symmetric light intensity distribution.

[0016] According to a preferred embodiment of the present invention, the step (5) is specifically as follows:

[0017] According to the local energy conservation law and optimal transport theory, without considering energy loss, it is required that all the energy of any thin beam emitted by the light source is transmitted to the target illumination area after being deflected by the free-form surface lens. The deflection of the thin beam by the free-form surface lens satisfies the following energy relationship:

[0018]

[0019] in, is the intensity distribution of the light source, E(tx1,ty1) is the illumination distribution of the target lighting area, J(T) is the Jacobi matrix of the position vector T, 0≤θ≤2π, in is the maximum divergence angle of the light beam incident on the free-form lens.

[0020] According to a preferred embodiment of the present invention, the step (6) is specifically as follows: all the light rays emitted by the light source are shaped by the free-form lens and have the same optical path length when arriving at a certain wavefront, that is, the following relationship is satisfied:

[0021] OPL=|OP|+n|PQ|+|QT|

[0022] Among them, OPL is the optical path of a certain light ray from the light source to a certain wavefront, |OP| is the distance between the light ray starting from the light source and the incident surface of the free-form surface, |PQ| is the distance between the intersection points of the light ray on the incident surface and the exit surface of the free-form surface, |QT| is the distance between the intersection points of the light ray on the exit surface and a certain wavefront, and n is the refractive index of the lens material.

[0023] According to a preferred embodiment of the present invention, the boundary condition in step (7) is specifically that the boundary light of the light beam of the non-rotationally symmetric light source is incident on the boundary of the illumination area of the target surface after being deflected by the free-form surface.

[0024] According to a preferred embodiment of the present invention, the step (8) is specifically to establish a correspondence between a point on the free surface and a landing point on the target surface, and to simultaneously solve the energy transfer equation in step (5) and the equal optical path relationship in step (6) to obtain the following elliptical second-order nonlinear partial differential equation:

[0025]

[0026] Where r is the distance between the points where the light falls on the incident and exit surfaces of the free-form surface, θ is the azimuth angle in the polar coordinate system, is the polar angle, r θ 、 are r in θ and The first-order partial derivative in the direction, r θθ 、 are r in θ and The second-order partial derivative in the direction, is r in θ and Second-order partial derivatives in both directions, A i (i=1,...,5) is r θ , r,θ and A1 is a function of The coefficient equation of the term, A2 is The coefficient equation of the term, A3 is r θθ The coefficient equation of the term, A4 is The coefficient equation of the term A5 is the constant term equation. The nonlinear partial differential equation is solved using a numerical solution method to obtain a set of discrete data points. By performing surface fitting on this set of data points, the surface distribution of the free-form surface is obtained.

[0027] According to a preferred embodiment of the present invention, the exit surface of the free-form surface lens is a free-form surface, or both the incident surface and the exit surface are free-form surfaces and do not have an axial rotational symmetry characteristic.

[0028] According to a preferred embodiment of the present invention, the refractive index of each region of the free-form surface lens is the same, and the medium surrounding the free-form surface lens is a uniform medium having a refractive index different from that of the lens, for example, air or other uniform medium having a refractive index different from that of the lens.

[0029] According to a preferred embodiment of the present invention, the free-form surface lens is a shaping lens after the light source.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The free-form surface shaping device for beam control of a light source with a non-rotationally symmetric light intensity distribution proposed in the present invention can achieve precise beam control of a light source with asymmetric light distribution on any target plane in three-dimensional space.

[0032] The free-form surface shaping device for light beam control of a light source with a non-rotationally symmetric light intensity distribution proposed in the present invention can simultaneously control the light intensity and wavefront distribution of the outgoing light of a light source with a non-symmetric light distribution.

[0033] The free-form surface shaping device proposed in the present invention for beam control of a light source with a non-rotationally symmetric light intensity distribution can significantly improve the energy utilization rate of the beam shaping system of a light source with asymmetric luminous distribution, thereby achieving energy conservation and environmental protection; it can significantly improve the compactness of the optical system and reduce the system volume; and it can design a continuous and smooth free-form surface shape, which is easy to process.

[0034] The free-form surface shaping device proposed in the present invention for beam control of a light source with a non-rotationally symmetric light intensity distribution can achieve complex lighting distribution and meet highly difficult lighting requirements; it can further broaden the application range of light sources with asymmetric luminous distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of beam shaping;

[0036] Figure 2 Schematic diagram of laser diode light emission;

[0037] Figure 3 It is the optical structure of the free-form surface lens;

[0038] Figure 4 This is the optical path structure diagram in Example 1;

[0039] Figure 5 is the free-form surface lens model in Example 1;

[0040] Figure 6 is the illuminance distribution diagram on the target illumination surface in Example 1;

[0041] Figure 7 This is a diagram of the optical path structure in Example 2;

[0042] Figure 8 is the free-form surface lens model in Example 2;

[0043] Figure 9 This is the illuminance distribution diagram on the target lighting surface in Example 2. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described below with reference to the accompanying drawings. Figure 1 and 9 As shown, the specific steps of the free-form surface shaping device for controlling the light beam of a light source with a non-rotationally symmetric light intensity distribution according to the present invention are as follows:

[0045] (1) A free-form surface optical path structure is provided, wherein light emitted by a light source whose luminous distribution does not have rotational symmetry is shaped by a free-form surface lens to present a specific radiant illuminance distribution and phase distribution on a target illumination surface. The target surface in the optical path structure is any target plane in three-dimensional space, which may be a vertical target plane or an off-axis target plane; the radiance distribution is uniform circular radiance, uniform rectangular radiance, or any radiance distribution that meets user needs; the phase distribution may be a plane wave phase, a spherical wave phase, or other phase distribution that meets predetermined requirements; and the light source in the embodiment is a laser diode whose luminous distribution does not have rotational symmetry.

[0046] (2) Determine the light distribution of the laser diode and the far-field divergence angle θ of its fast and slow axes || and θ ⊥ ;

[0047] (3) Determine a virtual light source, wherein the virtual light source has a rotationally symmetric light distribution, and θ initial⊥ =θ initial|| =θ ⊥ ;

[0048] (4) designing an initial free-form surface structure according to the rotationally symmetric initial light source described in step (3), wherein the initial structure is an aspherical surface;

[0049] (5) Based on the optimal transport theory and the law of refraction, the energy conservation and transformation relationship between the light source and the target illumination in step (3) is established. According to the law of local energy conservation, without considering energy loss, it is required that all the energy of any thin light beam emitted by the light source is transmitted to the target illumination area after being deflected by the free-form surface lens. The deflection of the thin light beam by the free-form surface lens satisfies the following energy relationship:

[0050]

[0051] in, is the intensity distribution of the light source, E(tx1,ty1) is the illumination distribution of the target lighting area, J(T) is the Jacobi matrix of the position vector T, 0≤θ≤2π, in is the maximum divergence angle of the light beam incident on the free-form lens.

[0052] (6) The optical path constraint condition is established based on the wavefront of the incident light beam and the wavefront of the target output light beam. The optical path of all light rays emitted by the light source after being shaped by the free-form surface lens and reaching a certain wavefront is equal, that is, the following relationship is satisfied:

[0053] OPL=|OP|+n|PQ|+|QT|

[0054] Where OPL is the optical path of a ray from the light source to a wavefront, |OP| is the distance from the light source to the incident surface of the freeform surface, |PQ| is the distance between the intersection points of the ray on the incident and exit surfaces of the freeform surface, |QT| is the distance between the intersection points of the ray on the exit surface and a wavefront, and n is the refractive index of the lens material.

[0055] (7) The boundary conditions for realizing the transformation from the incident boundary to the exit boundary are established based on the non-rotationally symmetric light distribution boundary of the incident light beam and the boundary of the target light spot.

[0056] (8) Based on the virtual light source in step (3), the initial aspheric structure in step (4) is numerically optimized, and a free-form surface lens that satisfies the illumination distribution is obtained by iterative calculation. The corresponding relationship between the points on the free-form surface and the landing points on the target surface is established. The energy transfer equation in step (5) and the equal optical path relationship in step (6) are solved simultaneously to obtain the following second-order nonlinear partial differential equation:

[0057]

[0058] Where r is the distance between the points where the light falls on the incident and exit surfaces of the free-form surface, θ is the azimuth angle in the polar coordinate system, is the polar angle, r θ 、 are r in θ and The first-order partial derivative in the direction, r θθ 、 are r in θ and The second-order partial derivative in the direction, is r in θ and Second-order partial derivatives in both directions, A i (i=1,...,5) is r θ , r,θ and A1 is a function of The coefficient equation of the term, A2 is The coefficient equation of the term, A3 is r θθ The coefficient equation of the term, A4 is The coefficient equation of the term A5 is the constant term equation. The nonlinear partial differential equation is solved by a numerical solution method to obtain a set of discrete data points. The surface distribution of the free-form surface is obtained by performing surface fitting on the set of data points. The free-form surface distribution is a free-form surface lens that satisfies the illumination distribution obtained based on the light source in step (3);

[0059] (9) Reduce the far-field divergence angle of the virtual light source in step (3), i.e., θ initial⊥ Keep it constant and gradually reduce θ initial|| , and perform step (8) to obtain the free-form surface shape based on the updated virtual light source beam control;

[0060] (10) Continue to reduce θ initial|| And proceed to step (9) until θ initial|| =θ || By making the light distribution of the virtual light source match the light distribution of the actual light source, the free-form surface data required for realizing the light beam control of the light source with non-rotationally symmetric light intensity distribution can be obtained.

[0061] Example 1: The free-form surface lens adopts the following Figure 3 The structure type shown in FIG1 is a spherical surface, and the emitting surface S2 is a free-form surface. The intensity of the laser diode is controlled on the inclined target surface by the free-form surface. The optical path structure is as follows: Figure 4 As shown, since the target surface of this example is an off-axis inclined surface in space, the control of the light beam in this example only considers the energy distribution, not the wavefront distribution. Therefore, the equal optical path relationship is not considered in the implementation steps of this example. The luminous intensity distribution of the light source is I = exp(-2((θ x / θ || ) 2 +(θ y / θ ⊥ ) 2 )) of the laser diode, where θ x ,θ y They are the angles between the outgoing light of the light source and the xz plane and the yz plane. Figure 2 ,θ || ,θ ⊥ They are the half angles of the laser diode light source in the x and y directions, that is, the intensity of the outgoing light is reduced to 1 / e of the intensity of the central light. 2 The half angle, θ || =5.5°、θ ⊥=20°, the output beam of the laser diode is required to produce a uniform rectangular spot distribution in the target illumination area on the spatial inclined surface after being refracted by the free-form surface lens, the vertex of the lens incident surface is 5mm away from the light source, the center thickness of the lens, that is, the distance between the vertex of the lens exit surface and the vertex of the incident surface, is 3mm, the intersection of the target illumination surface and the optical axis is 173mm away from the light source, the inclination angle of the target illumination surface is β=30°, the rectangular illumination spot is 124mm long and 80mm wide, the refractive index of the free-form surface lens material is 1.584, and the medium surrounding the lens is air.

[0062] Determine a virtual light source, wherein the virtual light source has a rotationally symmetric light distribution, and θ initial⊥ =θ initial|| =θ ⊥ =20°;

[0063] Designing an initial structure of a free-form surface (exit surface) based on the rotationally symmetric initial light source, wherein the initial structure is an aspherical surface;

[0064] An energy conservation relationship is established between the light source and the target radiance. According to the local energy conservation law, without considering energy loss, it is required that all the energy of any thin beam emitted by the light source is transmitted to the target illumination area after being deflected by the free-form surface lens. Further simplification results in the following relationship:

[0065]

[0066] Where r is the distance between the points where the light falls on the incident and exit surfaces of the free-form surface, θ is the azimuth angle in the polar coordinate system, is the polar angle, r θ 、 are r in θ and The first-order partial derivative in the direction, r θθ 、 are r in θ and The second-order partial derivative in the direction, is r in θ and Second-order partial derivatives in both directions, A i (i=1,...,5) is r θ , r,θ and A1 is a function of The coefficient equation of the term, A2 is The coefficient equation of the term, A3 is r θθ The coefficient equation of the term, A4 is A5 is the coefficient equation of the constant term.

[0067] Establish boundary conditions to ensure that the boundary light of the light beam is incident on the boundary of the target surface illumination area after being deflected by the free-form surface;

[0068] The nonlinear equations are solved by using the difference substitution differential method and Newton's method to obtain a set of discrete data points, that is, the discrete data points on the free-form surface are obtained. The free-form lens satisfies the free-form surface lens of the virtual light source.

[0069] Reduce the far-field divergence angle of the virtual light source, i.e., θ initial⊥ Keep 20° unchanged and gradually reduce θ initial|| , and repeat the above steps to iteratively solve, and obtain the free-form surface shape based on the updated virtual light source beam control;

[0070] Continue to reduce θ initial|| Repeat the above steps until θ initial|| =θ || =5.5°, so that the light distribution of the virtual light source is consistent with the light distribution of the actual light source, thereby obtaining the free-form surface data required for realizing the light beam control of the light source with non-rotationally symmetric light intensity distribution.

[0071] The free-form surface lens model can be obtained by performing surface fitting on the discrete data points of the free-form surface in CAD software. Figure 5 By tracing the free-form surface, the illumination distribution diagram on the inclined target surface is obtained. Figure 6 The illuminance distribution diagram clearly shows that the free-form surface lens proposed in the present invention for beam shaping of a light source with a non-rotationally symmetric light intensity distribution can shape the light distribution of the laser diode into a uniform illuminance distribution on a spatially inclined target surface.

[0072] Example 2: The free-form surface lens adopts the following Figure 3 The structure type shown in FIG1 is a structure in which both the incident surface S1 and the exit surface S2 are free-form surfaces. The wavefront and intensity of the laser diode output beam are simultaneously controlled on the vertical target surface through the free-form surfaces. The optical path structure is as follows: Figure 7 The luminous intensity distribution of the light source is the same as that in Example 1. The laser diode's outgoing beam is required to have a spherical wave shape after being refracted by the free-form lens and to have a uniform illumination distribution on the target surface. The illumination distribution is circular, the vertex of the lens's incident surface is 4 mm from the light source, and the lens's center thickness, i.e., the distance between the vertex of the exit surface and the vertex of the incident surface, is 4 mm. The target illumination surface is perpendicular to the optical axis, the refractive index of the free-form lens material is 1.384, and the medium surrounding the lens is air.

[0073] Determine a virtual light source, wherein the virtual light source has a rotationally symmetric light distribution, and θ initial⊥ =θ initial|| =θ ⊥ =20°;

[0074] Designing a free-form surface initial structure based on the rotationally symmetric initial light source, wherein the initial structure is an aspherical surface;

[0075] An energy conservation relationship is established between the light source and the target radiance. According to the local energy conservation law, without considering energy loss, it is required that all the energy of any thin beam emitted by the light source is transmitted to the target illumination area after being deflected by the free-form surface lens. Further simplification results in the following relationship:

[0076]

[0077] Where r is the distance between the points where the light falls on the incident and exit surfaces of the free-form surface, θ is the azimuth angle in the polar coordinate system, is the polar angle, r θ 、 are r in θ and The first-order partial derivative in the direction, r θθ 、 are r in θ and The second-order partial derivative in the direction, is r in θ and Second-order partial derivatives in both directions, A i (i=1,...,5) is r θ , r,θ and A1 is a function of The coefficient equation of the term, A2 is The coefficient equation of the term, A3 is r θθ The coefficient equation of the term, A4 is The coefficient equation of the term, A5 is the constant term equation;

[0078] Establish an optical path equality relationship. All the light rays emitted by the light source have the same optical path length when they reach a certain wave surface after being shaped by the free-form lens. That is, the following relationship is satisfied:

[0079] OPL=|OP|+n|PQ|+|QT|

[0080] Where OPL is the optical path of a ray from the light source to a wavefront, |OP| is the distance from the light source to the incident surface of the free-form surface, |PQ| is the distance between the intersection of the ray on the incident and exit surfaces of the free-form surface, |QT| is the distance between the intersection of the ray on the exit surface and a wavefront, and n is the refractive index of the lens material, n = 1.49386.

[0081] Boundary conditions are established to ensure that the boundary light of the light beam is incident on the boundary of the illumination area of the target surface after being deflected by the free-form surface.

[0082] The energy transfer equation and boundary conditions are converted into a nonlinear system of equations using the difference substitution method. Finally, the nonlinear system of equations is solved using the Newton method to obtain a set of discrete data points, that is, the discrete data points on the free-form surface lens are obtained. The free-form surface lens satisfies the above-mentioned virtual light source.

[0083] Reduce the far-field divergence angle of the virtual light source, i.e., θ initial⊥ Keep 20° unchanged and gradually reduce θ initial|| , and repeat the above steps to iteratively solve, and obtain the free-form surface shape based on the updated virtual light source beam control;

[0084] Continue to reduce θ initial|| Repeat the above steps until θ initial|| =θ || =5.5°, so that the light distribution of the virtual light source is consistent with the light distribution of the actual light source, thereby obtaining the free-form surface data required for realizing the light beam control of the light source with non-rotationally symmetric light intensity distribution.

[0085] The free-form surface lens model can be obtained by performing surface fitting on the discrete data points of the free-form surface in CAD software. Figure 8 By tracing the free-form surface, the illumination distribution diagrams on the target surface at 50mm and 80mm from the light source are shown in the attached figure. Figure 9 The illuminance distribution diagram clearly shows that a lighting effect with good illuminance uniformity can be obtained on the target illumination surface at different distances. It can be seen that the outgoing light beam is a spherical wave. The free-form surface shaping device for beam control of a light source with a non-rotationally symmetric light intensity distribution proposed in the present invention can simultaneously control the wavefront and intensity of the laser diode outgoing light beam.

[0086] The above two design examples clearly demonstrate that the free-form surface shaping device proposed in the present invention for beam control of a light source with a non-rotationally symmetric light intensity distribution effectively achieves complex shaping effects, and only uses a free-form surface lens to achieve high-quality beam shaping. The system is compact and light, and the beam energy utilization rate is high.

Claims

1. A free-form surface shaping device for beam control of a light source with a non-rotationally symmetric light intensity distribution, characterized in that The invention comprises a light source (U) having a non-rotationally symmetric light intensity distribution and a free-form surface lens (V); the optical axis of the light source coincides with the optical axis of the free-form surface lens; the free-form surface lens comprises an incident surface (S1) and an exit surface (S2); the incident surface and the exit surface do not have rotational symmetry; the non-rotationally symmetric light intensity distribution and phase distribution emitted by the light source are regulated by the free-form surface lens to generate a predetermined radiant illumination distribution and phase distribution on a predetermined target surface; the free-form surface lens is designed by the following steps: First, a free-form surface lens optical path structure is set up. Light emitted from a light source with a non-rotationally symmetric light intensity distribution is beam-shaped by the free-form surface lens to present a specific radiant illumination distribution and phase distribution on the target illumination surface. The target surface in the optical path structure is an arbitrary target plane in three-dimensional space, and the radiant illumination distribution and phase distribution on the target surface are pre-set according to user requirements.

2. Determine the luminous distribution of a light source whose luminous intensity does not have rotational symmetry, and determine the far-field divergence angle θ of its fast and slow axes || and θ ⊥ ; 3. Determine a virtual light source, wherein the virtual light source has a rotationally symmetric light distribution, and θ initial⊥ =θ initial|| =θ ⊥ ; 4. Designing an initial structure of a free-form surface lens based on the rotationally symmetric virtual light source described in step 3, wherein the initial structure is an aspherical surface; 5. Establish the energy conservation and transformation relationship between the light source and target illumination in step 3 based on the optimal transport theory and the law of refraction; 6. Establish optical path constraints based on the wavefront of the incident beam and the wavefront of the target outgoing beam; 7. Establishing boundary conditions for transforming the incident boundary to the exit boundary based on the non-rotationally symmetric light distribution boundary of the incident light beam and the boundary of the target light spot; 8. Based on the virtual light source in step 3, the initial aspheric structure in step 4 is numerically optimized, and a free-form surface lens that satisfies the illumination distribution is obtained by iterative calculation; 9. Reduce the far-field divergence angle of the virtual light source in step 3, i.e. θ initial⊥ Keep it constant and gradually reduce θ initial|| , and proceed to step eight to obtain the free-form surface shape based on the updated virtual light source beam control; 10. Continue to reduce θ initial|| And proceed to step nine until θ initial|| =θ || The light distribution of the virtual light source is made consistent with the light distribution of the actual light source, thereby obtaining the free-form surface lens surface data required to realize the light beam control of the light source with non-rotationally symmetric light intensity distribution.

2. The free-form surface shaping device for beam control of a light source with a non-rotationally symmetric light intensity distribution according to claim 1, characterized in that The step five is specifically as follows: According to the local energy conservation law and optimal transport theory, without considering energy loss, it is required that all the energy of any thin beam emitted by the light source is transmitted to the target illumination area after being deflected by the free-form surface lens. The deflection of the thin beam by the free-form surface lens satisfies the following energy relationship: in, is the intensity distribution of the light source, E(tx1,ty1) is the illumination distribution of the target lighting area, J(T) is the Jacobi matrix of the position vector T, 0≤θ≤2π, in is the maximum divergence angle of the light beam incident on the free-form lens.

3. The free-form surface shaping device for controlling the light beam of a light source with a non-rotationally symmetric light intensity distribution according to claim 1, characterized in that: Specifically, the sixth step is that all the light rays emitted by the light source have the same optical path length after being shaped by the free-form lens and arriving at a certain wavefront, that is, the following relationship is satisfied: OPL=|OP|+n|PQ|+|QT| Among them, OPL is the optical path of a certain light ray from the light source to a certain wavefront, |OP| is the distance between the light ray starting from the light source and the incident surface of the free-form surface, |PQ| is the distance between the intersection points of the light ray on the incident surface and the exit surface of the free-form surface, |QT| is the distance between the intersection points of the light ray on the exit surface and a certain wavefront, and n is the refractive index of the lens material.

4. The free-form surface shaping device for controlling the light beam of a light source with a non-rotationally symmetric light intensity distribution according to claim 1, characterized in that: The boundary condition in step seven is specifically that the boundary light of the light beam of the non-rotationally symmetric light source is incident on the boundary of the illumination area of the target surface after being deflected by the free-form surface.

5. The free-form surface shaping device for controlling the light beam of a light source with a non-rotationally symmetric light intensity distribution according to claim 1, characterized in that: The step eight specifically includes establishing a correspondence between points on the free surface and landing points on the target surface, and simultaneously solving the energy transfer equation in step five and the equal optical path relationship in step six to obtain the following elliptical second-order nonlinear partial differential equation: Where r is the distance between the points where the light falls on the incident and exit surfaces of the free-form surface, θ is the azimuth angle in the polar coordinate system, is the polar angle, r θ 、 are r in θ and The first-order partial derivative in the direction, r θθ 、 are r in θ and The second-order partial derivative in the direction, is r in θ and Second-order partial derivatives in both directions, A i (i=1,...,5) is r θ , r,θ and A1 is a function of The coefficient equation of the term, A2 is The coefficient equation of the term, A3 is r θθ The coefficient equation of the term, A4 is The coefficient equation of the term, A5 is the constant term equation; The nonlinear partial differential equation is solved by numerical solution method to obtain a set of discrete data points. The surface distribution of the free-form surface is obtained by performing surface fitting on the set of data points.

6. The free-form surface shaping device for controlling the light beam of a light source with a non-rotationally symmetric light intensity distribution according to claim 1, characterized in that The exit surface of the free-form surface lens is a free-form surface, or both the incident surface and the exit surface are free-form surfaces, and do not have an axial rotational symmetry characteristic.

7. The free-form surface shaping device for controlling the light beam of a light source with a non-rotationally symmetric light intensity distribution according to claim 1, characterized in that The refractive index of each region of the free-form surface lens is the same, and the medium surrounding the free-form surface lens is a uniform medium whose refractive index is different from that of the lens.

8. The free-form surface shaping device for controlling the light beam of a light source with a non-rotationally symmetric light intensity distribution according to claim 1, characterized in that The free-form surface lens is a shaping lens behind the light source.

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