An optical system

Abstract

The application discloses an optical system, comprising a light source emitting excitation light, a first lens group for converging and / or focusing the excitation light, a wavelength conversion unit for converting the excitation light into illumination light, and a second lens group for converging and / or collimating the illumination light; the light beam quality product of the light source on the y-axis is less than the light beam quality product on the x-axis; the first lens group at least comprises a cylindrical lens, the combined focal length of the first lens group in the x-axis direction is f1x, and the combined focal length of the first lens group in the y-axis direction is f1y, wherein the f1x and f1y satisfy 1.05<=f1x / f1y<=2.2. The optical system can better converge the laser on the wavelength conversion unit and ensure the excitation effect, and the optical system can also efficiently collect the illumination light, and the optical effect is excellent.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical technology, and more particularly, to an optical system. BACKGROUND

[0002] Solid-state light source has been widely applied in general lighting, special lighting and projection display due to its long service life, energy saving and environmental protection and other characteristics. Laser is another emerging solid-state light source after LED. One of the main ways of laser lighting is that laser irradiates on a wavelength conversion unit, and the wavelength conversion unit converts the laser into illumination light. For a high-power laser module, the laser is usually emitted by a laser array composed of multiple lasers. After the laser irradiates on the wavelength conversion unit, the laser is converted into illumination light, and then the illumination light is collected by a light collecting assembly. However, the beam quality product BPP (Beam-parameter product) of the laser emitted by the laser array in the x y direction is usually not equal, thereby causing the laser spot to be non-uniform in the x y direction, which affects the excitation of the wavelength conversion unit by the laser. In order to concentrate energy and achieve good excitation effect, the laser spot of the laser emitted by the laser array also needs to be shaped. In addition, when the laser irradiates on a wavelength conversion unit such as a fluorescent powder sheet, the light is basically emitted at an angle of 180 degrees. If the light cannot be well collected, the brightness will be significantly reduced, and therefore a light collecting assembly with a large numerical aperture (NA) needs to be added to collect the light to meet the brightness requirement. SUMMARY

[0003] The present application aims to overcome at least one of the above-mentioned defects of the prior art, and provides an optical system capable of better converging laser on a wavelength conversion unit and ensuring excitation effect, and the optical system can also efficiently collect illumination light, and the optical effect is excellent.

[0004] The technical scheme adopted by the present application is as follows:

[0005] An optical system, comprising a light source emitting excitation light, a first lens group for converging and / or focusing the excitation light, a wavelength conversion unit for converting the excitation light into illumination light, and a second lens group for converging and / or collimating the illumination light;

[0006] The beam quality product of the light source in the y-axis direction is less than the beam quality product in the x-axis direction;

[0007] The first lens group comprises at least one cylindrical lens, the combined focal length of the first lens group in the x-axis direction is f1x, and the combined focal length of the first lens group in the y-axis direction is f1y, and the f1x and f1y satisfy: 1.05≤f1x / f1y≤2.2;

[0008] The second lens group comprises at least a fourth lens with positive tortuosity close to the wavelength conversion unit, the effective aperture of the fourth lens is D4, the gap distance between the fourth lens and the wavelength conversion unit is L21, D4 and L21 satisfy: 13 < D4 / L21 < 17.

[0009] The first lens group and the second lens group are coaxial and are on the z-axis.

[0010] In one embodiment, the first lens group comprises a first lens, a second lens and a third lens arranged coaxially in sequence, the first lens is a cylindrical lens with negative tortuosity, the distance between the light entrance surface of the first lens and the excited surface of the wavelength conversion unit is L1, L1, f1x and f1y satisfy: 0.7 < L1 / f1x < 1.4; 1.1 < L1 / f1y < 1.7.

[0011] In one embodiment, at least one surface of the first lens in the x-axis direction is concave, the focal length of the first lens in the x-axis direction is f11x, f11x and flx satisfy: 1 ≤ |f11x| / flx ≤ 8.

[0012] In one embodiment, the second lens is a lens with positive tortuosity, the light entrance surface is convex with a radius of curvature R21, and the light exit surface is a plane; the effective aperture of the second lens is D2, the focal length of the second lens is f12, R21 and D2 satisfy: 1.0 ≤ |R21| / D2 ≤ 1.5, and f12 > |f1y|.

[0013] In one embodiment, the third lens is a lens with positive tortuosity, the light entrance surface is convex with a radius of curvature R31, and the light exit surface is concave with a radius of curvature R32, the effective aperture of the third lens is D3, the focal length of the third lens is f13, R31, R32, D3 and f13 satisfy: |R31|*1.2 < |R32| < |R31|*2, 0.45 ≤ |R31| / D3 ≤ 0.82, and f13 > |f1y|.

[0014] In one embodiment, the second lens group comprises a fourth lens and a fifth lens arranged coaxially, the combined focal length of the second lens group is f2, the farthest distance from the excited surface of the wavelength conversion unit to the light exit surface of the fifth lens is L2, L2 and f2 satisfy: 0.42 < f2 / L2 < 0.65.

[0015] In one of the embodiments, the fourth lens is a plano-convex lens with positive tortuosity, the light-receiving surface facing the wavelength conversion unit is a plane, the light-emitting surface facing away from the wavelength conversion unit is a convex surface with a radius of curvature R42, the effective light-passing aperture of the fourth lens is D4, and the R42 and D4 satisfy: 0.38≤|R42| / D4≤0.65; the focal length of the fourth lens is f21, and 0.46

[0016] In one of the embodiments, the fifth lens is a plano-convex aspheric lens with positive tortuosity, the light-receiving surface facing the wavelength conversion unit is a plane, the light-emitting surface facing away from the wavelength conversion unit is a convex aspheric surface with an approximate spherical radius of curvature R52, the effective light-passing aperture of the fifth lens is D5, and the R52 and D5 satisfy: 0.28≤|R52| / D5≤0.62; the focal length of the fifth lens is f22, and 0.4

[0017] In one of the embodiments, the central thickness of the second lens is T2, and the T2 satisfies: 6<|R21| / T2<11; and / or, the central thickness of the fourth lens is T4, and the T4 satisfies: 1.1<|R42| / T4<1.6.

[0018] In one of the embodiments, a light homogenizing diffusion sheet is further arranged between the first lens group and the wavelength conversion unit.

[0019] In one of the embodiments, the light source emitting excitation light is a laser light source, and the laser light source comprises n×m lasers, where n≥2 and m≥2.

[0020] In one of the embodiments, the laser light source comprises n×m laser chips and a plurality of collimating lenses arranged correspondingly to the laser chips, and the n×m laser chips and the plurality of collimating lenses form a laser array. The laser light emitted by the laser chips is laser light with a wavelength of 400-600 nm.

[0021] In one of the embodiments, the wavelength conversion unit is a fluorescent color wheel.

[0022] Compared with the prior art, the present application has the beneficial effects that: the first lens group with a specific structure is used to converge / collimate the excitation light, so that the BPP of the laser emitted by the laser array in the x y direction is almost equal after being converged and / or focused by the first lens group, a circular laser spot can be obtained, the excitation efficiency of the wavelength conversion unit is high, and the second lens group with a specific structure is used to converge / collimate the illumination light, so that large-angle high-light-collection-rate light collection can be realized, the illuminance is high, and the optical effect is excellent. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a structural diagram of the optical system of the embodiment of the present application.

[0024] Figure 2 It is an x-z direction optical structure diagram of the optical system of the embodiment of the present application.

[0025] Figure 3 It is a y-z direction optical structure diagram of the optical system of the embodiment of the present application.

[0026] Figure 4 It is a simulation analysis point array diagram of the first lens group of the embodiment 1 of the present application.

[0027] Figure 5 It is a simulation analysis phase difference diagram of the first lens group of the embodiment 1 of the present application.

[0028] Figure 6 It is a simulation analysis point array diagram of the second lens group of the embodiment 1 of the present application.

[0029] Figure 7 It is a simulation analysis phase difference diagram of the second lens group of the embodiment 1 of the present application.

[0030] Figure 8 It is an optical simulation diagram of the embodiment 1 of the present application.

[0031] Figure 9 It is an optical simulation diagram without the first lens of the relative embodiment 1.

[0032] Figure 10 It is a simulation analysis point array diagram of the first lens group of the embodiment 2 of the present application.

[0033] Figure 11 It is a simulation analysis phase difference diagram of the first lens group of the embodiment 2 of the present application.

[0034] Figure 12 It is a simulation analysis point array diagram of the second lens group of the embodiment 2 of the present application.

[0035] Figure 13 It is a simulation analysis phase difference diagram of the second lens group of the embodiment 2 of the present application.

[0036] Figure 14 Optical simulation diagram for the first lens of the optical system of the present application.

[0037] Figure 15 Optical simulation diagram for the first lens of the optical system of the present application.

[0038] Figure 16 Simulated analysis point diagram for the first lens group of the optical system of the present application.

[0039] Figure 17 Simulated analysis phase difference diagram for the first lens group of the optical system of the present application.

[0040] Figure 18 Simulated analysis point diagram for the second lens group of the optical system of the present application.

[0041] Figure 19 Simulated analysis phase difference diagram for the second lens group of the optical system of the present application.

[0042] Figure 20 Simulated analysis point diagram for the optical system of the present application.

[0043] Figure 21 Optical simulation diagram for the first lens of the optical system of the present application.

[0044] BRIEF DESCRIPTION OF DRAWINGS: 10, first lens group; 11, first lens; 12, second lens; 13, third lens; 20, second lens group; 21, fourth lens; 22, fifth lens; 30, wavelength conversion unit; 40, light source; 41, laser chip; 42, collimating lens; 50, light homogenizing and diffusing sheet; 60, light output lens. DETAILED DESCRIPTION

[0045] The drawings of the present application are only used for illustrative purposes and should not be understood as limiting the present application. In order to better illustrate the following embodiments, some components in the drawings may be omitted, enlarged or reduced, and do not represent the actual size of the product; it is understandable for those skilled in the art that some well-known structures and their descriptions in the drawings may be omitted.

[0046] The inventors found during the research that the BPP (Beam-parameter product) of the laser emitted by the laser chip array in the x y direction is usually not equal, resulting in uneven laser spots in the x y direction, and the excitation efficiency of the laser is affected. In addition, part of the laser is converted into stimulated light after being excited, and the mixed stimulated light and unexcited laser can form illumination light, but the existing light collecting assembly for collecting illumination light usually has a small numerical aperture and low light collecting efficiency, resulting in insufficient luminous flux and illuminance of the illumination light.

[0047] Based on this, the technical scheme of the present application is proposed.

[0048] In one embodiment of the present application, an optical system includes a light source emitting excitation light, a first lens group for converging and / or focusing the excitation light, a wavelength conversion unit for converting the excitation light into illumination light, and a second lens group for converging and / or collimating the illumination light; the light source has a beam quality product in the y-axis direction smaller than that in the x-axis direction; the first lens group includes at least a cylindrical lens, the first lens group has a combined focal length f1x in the x-axis direction and a combined focal length f1y in the y-axis direction, and the f1x and f1y satisfy 1.05≤f1x / f1y≤2.2; the second lens group includes at least a fourth lens having positive toroidal power close to the wavelength conversion unit, the fourth lens has an effective clear aperture D4, and the fourth lens and the wavelength conversion unit have a gap distance L21, and the D4 and L21 satisfy 13<D4 / L21<17; the first lens group and the second lens group are coaxial and have a z-axis.

[0049] The optical system provided by the present application can efficiently perform optical processing on excitation light having different BPPs in the x and y directions to obtain illumination light with excellent optical efficiency. By arranging a cylindrical lens in the first lens group and controlling the combined focal lengths of the first lens group in the x and y directions, the optical system can perform optical shaping on the excitation light to obtain a circular light spot, so that the energy density of the light spot focused on the wavelength conversion unit is high and the excitation efficiency is high. By controlling the distance between the fourth lens in the second lens group and the wavelength conversion unit and the effective clear aperture of the fourth lens, the numerical aperture of the second lens group is increased as much as possible, so that the light collection efficiency of the second lens group is high, thereby effectively improving the overall light collection efficiency of the optical system.

[0050] In any embodiment, the ratio of the beam quality product in the y-axis direction to that in the x-axis direction of the light source is 0.5-0.9.

[0051] In any embodiment, the f1x and f1y satisfy 1.1≤f1x / f1y≤2. Further, the f1x and f1y satisfy 1.14≤f1x / f1y≤1.8.

[0052] In any embodiment, the D4 and L21 satisfy 14≤D4 / L21≤16. Further, the D4 and L21 satisfy 14≤D4 / L21≤15.

[0053] In any embodiment, the first lens group comprises a first lens, a second lens and a third lens arranged coaxially in sequence, the first lens is a cylindrical lens with negative power, the distance between the light entrance surface of the first lens and the excited surface of the wavelength conversion unit is L1, the L1, f1x and f1y satisfy: 0.7 < L1 / f1x < 1.4; 1.1 < L1 / f1y < 1.7.

[0054] In the embodiment, the first lens in the first lens group is a cylindrical lens with negative power, which functions to correct the BPP of the excitation light in the x and y directions, and further control the ratio of the combined focal length f1y of the first lens group in the y axis direction to L1 and the ratio of the combined focal length f1x of the first lens group in the x axis direction to L1, so that the overall size of the first lens group is small and the structure is compact.

[0055] In any embodiment, the L1, f1x and f1y satisfy: 0.9 ≤ L1 / f1x ≤ 1.24; 1.4 ≤ L1 / f1y ≤ 1.5

[0056] In any embodiment, the first lens has at least one concave surface in the x axis direction, the focal length of the first lens in the x axis direction is f11x, and the f11x and flx satisfy: 1 ≤ |f11x| / flx ≤ 8.

[0057] In any embodiment, the f11x and flx satisfy: 1.77 ≤ |f11x| / flx ≤ 7.2.

[0058] In any embodiment, the second lens is a lens with positive power, the light entrance surface of the second lens is convex with a radius of curvature R21, and the light exit surface is a plane; the effective light aperture of the second lens is D2, the focal length of the second lens is f12, the R21 and D2 satisfy: 1.0 ≤ |R21| / D2 ≤ 1.5, and f12 > |f1y|.

[0059] The second lens is used to further focus the light focused / converged by the first lens, and reduce the size of the light collection system.

[0060] In any embodiment, 1.18 ≤ |R21| / D2 ≤ 1.23.

[0061] In any embodiment, the third lens is a lens with positive tortuosity, the entrance surface of which is convex with a radius of curvature R31, and the exit surface of which is concave with a radius of curvature R32, the effective light aperture of the third lens is D3, the focal length of the third lens is f13, and the R31, R32, D3, and f13 satisfy the following conditions: |R31|*1.2<|R32|<|R31|*2, 0.45≤|R31| / D3≤0.82, and the f13>|f1y|.

[0062] The third lens adopts the above lens, which can better correct aberration and shorten the focal length of the first lens group, thereby ensuring the focusing effect of the first lens group.

[0063] In any embodiment, the R31, R32, D3, and f13 satisfy the following conditions: |R31|*1.64≤|R32|≤|R31|*1.66, 0.63≤|R31| / D3≤0.68.

[0064] In any embodiment, the second lens group comprises a fourth lens and a fifth lens coaxially arranged, the combined focal length of the second lens group is f2, the farthest distance from the excitation surface of the wavelength conversion unit to the exit surface of the fifth lens is L2, and the L2 and f2 satisfy the following condition: 0.42

[0065] In any embodiment, 0.52≤f2 / L2≤0.54.

[0066] In any embodiment, the fourth lens is a plano-convex lens with positive tortuosity, the light receiving surface of which faces the wavelength conversion unit is a plane, and the exit surface of which faces away from the wavelength conversion unit is convex with a radius of curvature R42, the effective light aperture of the fourth lens is D4, the R42 and D4 satisfy the following condition: 0.38≤|R42| / D4≤0.65, the focal length of the fourth lens is f21, 0.46

[0067] In any embodiment, the R42 and D4 satisfy the following condition: 0.51≤|R42| / D4≤0.54.

[0068] In any embodiment, the 0.57≤f2 / f21≤0.59, 1.52≤f21 / |R42|≤1.54.

[0069] In any embodiment, the fifth lens is a plano-convex aspheric lens with positive toroidal power, the surface facing the light collecting surface of the wavelength conversion unit is a plane, the surface facing away from the light collecting surface of the wavelength conversion unit is a convex aspheric surface and the approximate spherical curvature radius thereof is R52, the effective light passing aperture of the fifth lens is D5, the R52 and D5 satisfy: 0.28≤|R52| / D5≤0.62; the focal length of the fifth lens is f22, 0.4

[0070] In any embodiment, the 0.39≤|R52| / D5≤0.4; 0.62≤f2 / f22≤0.64, 1.52≤f22 / |R52|≤1.54.

[0071] The fourth lens above is used to collect the illumination light at the maximum angle, the fifth lens is used to minimize the total optical length as much as possible and correct aberration to ensure collimation.

[0072] In any embodiment, the central thickness of the second lens is T2 respectively, the T2 satisfy: 6

[0073] In any embodiment, 7≤|R21| / T2≤11.

[0074] In any embodiment, 1.3≤|R42| / T4≤1.4.

[0075] In any embodiment, the gap distance between the wavelength conversion unit and the fourth lens and the gap distance between the fourth lens and the fifth lens are L21 and L22 respectively, the L21 and L22 satisfy: 2.8*L22

[0076] In any embodiment, 3.7*L22≤L21≤4.5*L22.

[0077] In any embodiment, a light homogenizing diffusion sheet is further arranged between the first lens group and the wavelength conversion unit.

[0078] In any embodiment, the light source emitting excitation light is a laser light source, the laser light source comprises n×m lasers, wherein n≥2, m≥2.

[0079] In any embodiment, the light source comprises n×m laser chips and collimating lenses corresponding to the laser chips, the n×m laser chips and the collimating lenses constitute a laser array. The laser chips emit laser light with a wavelength of 400-600 nm.

[0080] In any embodiment, the wavelength conversion unit is a fluorescent color wheel. Further, the fluorescent color wheel is a transmissive fluorescent color wheel. Further, the fluorescent color wheel comprises a transmissive fluorescent color sheet and a driving mechanism for driving the transmissive fluorescent color sheet to rotate.

[0081] In any embodiment, the first lens, the second lens, the third lens, the fourth lens and the fifth lens are all glass lenses, and the refractive index nd of the used material satisfies: 1.45 < nd < 1.88.

[0082] Further details will be described in combination with specific parameters.

[0083] The light-in surface described in the following embodiments refers to the surface close to the light source, the light-out surface described in the following embodiments refers to the surface away from the light source, and the light-receiving surface described in the following embodiments refers to the surface close to the wavelength conversion unit.

[0084] Embodiment 1

[0085] As shown in Figure 1 , Figure 2 , Figure 3 The embodiment discloses an optical system, which comprises a light source 40 for emitting excitation light, a first lens group 10 for collecting and / or focusing the excitation light, a wavelength conversion unit 30 for converting the excitation light into illumination light, and a second lens group 20 for collecting and / or collimating the illumination light.

[0086] The light source 40 has a beam quality product in the y-axis direction smaller than a beam quality product in the x-axis direction.

[0087] The first lens group comprises at least one cylindrical lens, the first lens group has a combined focal length f1x in the x-axis direction and a combined focal length f1y in the y-axis direction, and the f1x and the f1y satisfy: 1.05 ≤ f1x / f1y ≤ 2.2.

[0088] The second lens group comprises at least a fourth lens close to the wavelength conversion unit and having positive tortuosity, the fourth lens has an effective light aperture D4, and the fourth lens and the wavelength conversion unit have a gap spacing L21, and the D4 and the L21 satisfy: 13 < D4 / L21 < 17.

[0089] The first lens group and the second lens group are coaxial and have the z-axis.

[0090] Specifically, in the embodiment, a beam quality product of the light source in the y-axis direction is BPPy, a ratio of a beam quality product in the x-axis direction is BPPx, and BPP0=BPPy / BPPx=0.86. A combined focal length of the first lens group in the x-axis direction is f1x=13.3 mm, and a combined focal length of the first lens group in the y-axis direction is f1y=11.7 mm, f1x / f1y=1.14.

[0091] An effective light aperture of the fourth lens is D4=19.5 mm, a gap distance L21 between the fourth lens and the wavelength conversion unit is 1.3 mm, and D4 / L21=15.

[0092] Further, in the embodiment, the first lens group comprises a first lens, a second lens and a third lens arranged coaxially in sequence. The first lens is a cylindrical lens with negative tortuosity, and at least one surface of the first lens in the x-axis direction is concave. Specifically, as shown in FIG. 1, the first lens 110 is a cylindrical lens with negative tortuosity, and the surface in the x-axis direction is concave. Figure 1 Figure 2 Figure 3 In other embodiments, the surface in the y-axis direction of the first lens 110 can be flat, and the surface in the x-axis direction can be concave. The surface of the second lens 120 can be flat, and the surface of the third lens 130 can be concave. The second lens 120 is a lens with positive tortuosity, and the surface facing the wavelength conversion unit is convex. The third lens 130 is a lens with positive tortuosity, and the surface facing the wavelength conversion unit is concave.

[0093] Further, in the embodiment, the second lens group comprises a fourth lens and a fifth lens arranged coaxially. The fourth lens is a plano-convex lens with positive tortuosity, and the surface facing the wavelength conversion unit is flat. The fifth lens is a plano-convex aspheric lens with positive tortuosity, and the surface facing the wavelength conversion unit is flat, and the surface away from the wavelength conversion unit is convex aspheric.

[0094] ​​Specifically, in the embodiment, the curvature radius of the light-incident surface of the first lens is R11, the curvature radius of the light-emitting surface in the y-axis direction is R12y, the curvature radiuses of the light-incident surface and the light-emitting surface of the second lens are R21 and R22 respectively, the curvature radiuses of the light-incident surface and the light-emitting surface of the third lens are R31 and R32 respectively, the curvature radiuses of the light-incident surface and the light-emitting surface of the fourth lens are R41 and R42 respectively, and the curvature radiuses of the light-incident surface and the light-emitting surface of the fifth lens are R51 and R52 (R52 is the approximate spherical curvature radius). The effective light apertures of the first lens, the second lens, the third lens, the fourth lens and the fifth lens are D1, D2, D3, D4 and D5 respectively, and the center thicknesses of the first lens, the second lens, the third lens, the fourth lens and the fifth lens are T1, T2, T3, T4 and T5 respectively. The parameters of the lenses in the embodiment are shown in Table 1.

[0095] Table 1

[0096]

[0097]

[0098] Further, the distance from the light-incident surface of the first lens to the excited surface of the wavelength conversion unit is L1, the farthest distance from the light-emitting surface of the wavelength conversion unit to the light-emitting surface of the fifth lens is L2, the gap distance between the first lens and the second lens and the gap distance between the second lens and the third lens are L12 and L13 respectively, and the gap distance between the fourth lens and the fifth lens is L22. Specifically, in the embodiment, L1 = 16.5 mm, L2 = 16.58 mm, L12 = 1 mm, L13 = 0.3 mm, and L22 = 0.3 mm.

[0099] Further, in the embodiment, the focal lengths of the second lens, the third lens, the fourth lens and the fifth lens are f12, f13, f21 and f22 respectively, f12 = 23.8 mm, f13 = 23.8 mm, f21 = 15.2 mm, f22 = 14 mm, and f2 = 8.9 mm.

[0100] Further, in the embodiment, the depth z of the aspheric surface of the light-emitting surface of the fifth lens satisfies:

[0101]

[0102] wherein α1 = α6 = α7 = α8 = 0;

[0103] k = -0.7, α2 = -2e -6 , α3 = -2.5e -7 , α4 = 1.56e -8 , and α5 = -5.3e -11 ;

[0104] c is 1 / R, R is the radius of curvature, k is the quadratic surface coefficient; r is the height. a1 to a8 are aspherical coefficients.

[0105] Further, in the embodiment, the gap distance between the first lens and the second lens, and the gap distance between the second lens and the third lens are L12 and L13 respectively, L12 = 1 mm, and L13 = 0.3 mm.

[0106] Further, in the embodiment, a light homogenizing diffusion sheet 50 is further arranged between the first lens group 10 and the wavelength conversion unit 30.

[0107] Further, the light source for emitting excitation light is a laser light source, and the laser light source includes n x m lasers, where n ≥ 2 and m ≥ 2. Figure 2 、 Figure 3 In the embodiment, the laser light source is taken as a 4 x 2 laser array as an example, and in other embodiments, other numbers of laser arrays can also be used, as long as the ratio of the product of the beam quality in the y-axis to the product of the beam quality in the x-axis is about 0.87.

[0108] Further, the laser light source includes 4 x 2 laser chips and 4 x 2 collimating lenses corresponding to the laser chips, and the 4 x 2 laser chips and the 4 x 2 collimating lenses form a laser array. The laser emitted by the laser chip is a laser with a wavelength of 400-600 nm.

[0109] Further, in the embodiment, the wavelength conversion unit 50 is a fluorescent color wheel. The fluorescent color wheel is a transmission type fluorescent color wheel. Further, the fluorescent color wheel includes a transmission type fluorescent color sheet and a driving mechanism for driving the transmission type fluorescent color sheet to rotate. The fluorescent color wheel can be a conventional structure on the market, which will not be described here.

[0110] Further, in the embodiment, the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are all glass lenses, and the refractive index nd of the material used satisfies: 1.45 < nd < 1.88.

[0111] The point diagram of the first lens group of the optical system described in Embodiment 1 after the light source is converged and / or focused is shown in FIG. 4, from which it can be seen that the first lens group can obtain a nearly circular laser spot, and the maximum RMS radius is about 21.6 μm. It can be seen that the first lens group can better focus the spot, and the spot aggregation effect is good. Figure 4 The aberration curve of the first lens group is shown in FIG. 5, from which it can be seen that the first lens group can obtain a nearly circular laser spot, and the maximum RMS radius is about 21.6 μm. It can be seen that the first lens group can better focus the spot, and the spot aggregation effect is good. Figure 5 The aberration curve of the first lens group is shown in FIG. 5, from which it can be seen that the first lens group can obtain a nearly circular laser spot, and the maximum RMS radius is about 21.6 μm. It can be seen that the first lens group can better focus the spot, and the spot aggregation effect is good. Figure 5It can be seen that the maximum scale of the focused light spot is ±50μm, indicating that the aberration of the focused light spot is small.

[0112] Taking the numerical aperture of 0.97 as the benchmark, the point diagram of the second lens group is as follows Figure 6 As shown, from Figure 6 It can be seen that the maximum RMS radius of the collimated spot is about 10.8μm, which shows that the collimation effect of the second lens group is good. The aberration curve of the second lens group is as follows: Figure 7 As shown, from Figure 7 It can be seen that the maximum scale of the collimated light spot is ±50μm, indicating that the light spot aberration is small after collimation.

[0113] The final optical simulation diagram of the optical system described in this embodiment is as follows: Figure 8 As shown (simulated distance is 20m), from Figure 8 It can be seen that the optical system described in this embodiment finally presents a circular light spot effect, and the maximum illumination at the center is 8.32×10 4 lux. When the first lens is not used, the optical simulation diagram is as follows Figure 9 As shown, from Figure 9 It can be seen that the light spot effect is ellipsoidal, and the maximum illumination at the center is 7.4×10 4 In this embodiment, the maximum central illumination is increased by about 12.4% after using the first lens.

[0114] Further, if Figure 1 As mentioned above, the optical system described in this embodiment also includes a light-emitting lens. The size and specifications of the light-emitting lens can be adjusted or changed accordingly due to different requirements of downstream products, and will not be described in detail here.

[0115] Example 2

[0116] like Figure 1 、 Figure 2 、 Figure 3 As shown, Figure 1 、 Figure 2 、 Figure 3As shown, the embodiment discloses an optical system, comprising a light source 40 emitting excitation light, a first lens group 10 for converging and / or focusing the excitation light, a wavelength conversion unit 30 for converting the excitation light into illumination light, and a second lens group 20 for converging and / or collimating the illumination light; the light source 40 has a beam quality product in the y-axis direction smaller than that in the x-axis direction; the first lens group at least comprises a cylindrical lens, the first lens group has a combined focal length f1x in the x-axis direction and a combined focal length f1y in the y-axis direction, and the f1x and f1y satisfy: 1.05≤f1x / f1y≤2.2; the second lens group at least comprises a fourth lens with positive tortuosity close to the wavelength conversion unit, the fourth lens has an effective clear aperture D4, and the fourth lens and the wavelength conversion unit have a gap spacing L21, and the D4 and L21 satisfy: 13<D4 / L21<17; the first lens group and the second lens group are coaxial and on the z-axis.

[0117] The optical system of the embodiment 2 has basically the same structure and working principle as those of the embodiment 1, and the difference lies in that the specific parameters have a small amount of change. The parameters of the embodiment 2 are as follows:

[0118] BPP0=0.54, f1x=23.8, f1y=13.2, f1x / f1y=1.8, f12=27.1mm, f13=27.4mm, f21=17.5mm, f22=16.3mm, f2=10.1mm, L1=18.9mm, L12=1.15mm, L13=0.3mm, L2=19.1mm, L21=1.5mm, L22=0.4mm. The parameters of each lens are shown in Table 2.

[0119] Table 2

[0120]

[0121] Further, in the embodiment, the depth z of the aspheric surface of the light exit surface of the fifth lens satisfies:

[0122]

[0123] Wherein, α1=α6=α7=α8=0;

[0124] k=-0.72, α2=-1.392e -6 , α3=-1.28e -7 , α4=5.74e -9 , α5=-1.51e -11 ;

[0125] c is 1 / R, R is the radius of curvature, k is the quadratic surface coefficient; r is the height. a1 to a8 are aspherical coefficients.

[0126] The other structures and working principles of this embodiment are the same as those of Embodiment 1, which will not be described here.

[0127] The point diagram of the first lens group of the optical system described in Embodiment 2 after converging and / or focusing of the light source is shown in Figure 10 From Figure 10 it can be seen that the optical system described in Embodiment 2 can obtain a nearly circular laser spot through the first lens group, and the RMS radius is about 25.2 μm at most, which shows that the first lens group can better focus the spot, and the spot gathering effect is good. The aberration curve of the first lens group is shown in Figure 11 From Figure 11 it can be seen that the maximum scale of the focused spot is ±50 μm, which shows that the aberration of the focused spot is small.

[0128] Taking the numerical aperture of 0.97 as a reference, the point diagram of the second lens group is shown in Figure 12 From Figure 12 it can be seen that the collimated spot RMS radius is about 13 μm, which shows that the collimation effect of the second lens group is good. The aberration curve of the second lens group is shown in Figure 13 From Figure 13 it can be seen that the maximum scale of the collimated spot is ±50 μm, which shows that the aberration of the collimated spot is small.

[0129] The final optical simulation diagram of the optical system described in Embodiment 2 is shown in Figure 14 From Figure 14 it can be seen that the optical system described in this embodiment finally presents a circular spot effect, and the maximum center luminance is 7.71×10 4 lux. When the first lens is not used, the optical simulation diagram is shown in Figure 15 From Figure 15 it can be seen that it presents an ellipsoidal spot effect, and the maximum center luminance is 4.29×10 4 . The maximum center luminance of this embodiment is improved by about 79.7% after using the first lens.

[0130] Embodiment 3

[0131] As shown in Figure 1 , Figure 2 , Figure 3 As shown in Figure 1 , Figure 2 , Figure 3As shown, the embodiment discloses an optical system, comprising a light source 40 emitting excitation light, a first lens group 10 for converging and / or focusing the excitation light, a wavelength conversion unit 30 for converting the excitation light into illumination light, and a second lens group 20 for converging and / or collimating the illumination light; the light source 40 has a beam quality product in the y-axis direction smaller than that in the x-axis direction; the first lens group at least comprises a cylindrical lens, the first lens group has a combined focal length f1x in the x-axis direction and a combined focal length f1y in the y-axis direction, and the f1x and f1y satisfy: 1.05≤f1x / f1y≤2.2; the second lens group at least comprises a fourth lens with positive tortuosity close to the wavelength conversion unit, the fourth lens has an effective clear aperture D4, and the fourth lens and the wavelength conversion unit have a gap spacing L21, and the D4 and L21 satisfy: 13<D4 / L21<17; the first lens group and the second lens group are coaxial and on the z-axis.

[0132] The optical system of the embodiment 2 has basically the same structure and working principle as those of the embodiment 1, and the difference lies in that the specific parameters have a small amount of change. The parameters of the embodiment 2 are as follows:

[0133] BPP0=0.64, f1x=23.7mm, f1y=15.5mm, f1x / f1y=1.53, f12=31.2mm, f13=31.4mm, f21=20mm, f22=18.7mm, f2=11.6mm, L1=21.8mm, L12=1.3mm, L13=0.38mm, L2=21.9mm, L21=1.74mm, L22=0.46mm.

[0134] The parameters of each lens are shown in Table 3.

[0135] Table 3

[0136]

[0137] Further, in the embodiment, the aspheric depth Z of the light exit surface of the third lens satisfies:

[0138] Further, in the embodiment, the aspheric depth z of the light exit surface of the fifth lens satisfies:

[0139]

[0140] Wherein, α1=α6=α7=α8=0;

[0141] k=-0.72, α2=-9.15e -7 , α3=-6.36e -8 , α4=2.1e -9, α5=-4.3e -12 ;

[0142] c is 1 / R, R is the radius of curvature, k is the quadratic surface coefficient, r is the height, and α1 to α8 are aspheric surface coefficients.

[0143] The other structures of this embodiment are the same as those of embodiment 1 and will not be described again here.

[0144] The point diagram after the first lens group of the optical system described in Example 3 converges and / or focuses the light source is shown in FIG16 . Figure 16 It can be seen that the optical system described in this embodiment can obtain a nearly circular laser spot through the first lens group, and the maximum RMS radius is about 26.3μm. It can be seen that the first lens group can better focus the laser spot and has a good light spot gathering effect. The aberration curve of the first lens group is shown in the figure below. Figure 17 As shown, from Figure 17 It can be seen that the maximum scale of the focused light spot is ±50μm, indicating that the aberration of the focused light spot is small.

[0145] Taking the numerical aperture of 0.97 as the benchmark, the point diagram of the second lens group is as follows Figure 18 As shown, from Figure 18 It can be seen that the maximum RMS radius of the collimated spot is about 12.5μm, which shows that the collimation effect of the second lens group is good. The aberration curve of the second lens group is as follows: Figure 19 As shown, from Figure 19 It can be seen that the maximum scale of the collimated light spot is ±50μm, indicating that the light spot aberration is small after collimation.

[0146] The final optical simulation diagram of the optical system described in Example 3 is as follows: Figure 20 As shown (simulated distance is 20m), from Figure 20 It can be seen that the optical system described in this embodiment finally presents a circular light spot effect, and the maximum illumination at the center is 8.4×10 4 lux. When the first lens is not used. The optical simulation diagram is as follows Figure 21 As shown, from Figure 21 It can be seen that the light spot effect it presents is ellipsoidal, and the maximum illumination at the center is 5.93×10 4 In this embodiment, the maximum central illumination is increased by about 41.7% after using the first lens.

[0147] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the technical solutions of the present invention, and are not intended to limit the specific implementation methods of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. An optical system characterized by comprising: The light source emits excitation light, the first lens group converges and / or focuses the excitation light, the wavelength conversion unit converts the excitation light into illumination light, and the second lens group converges and / or collimates the illumination light; The light source has a beam quality product in the y-axis direction smaller than a beam quality product in the x-axis direction; The first lens group includes at least one cylindrical lens, the first lens group has a combined focal length f1x in the x-axis direction and a combined focal length f1y in the y-axis direction, and the f1x and f1y satisfy 1.05≤f1x / f1y≤2.2; The second lens group includes at least one fourth lens having positive toroidal power close to the wavelength conversion unit, the fourth lens has an effective clear aperture D4, and the fourth lens and the wavelength conversion unit have a gap spacing L21, and the D4 and L21 satisfy 13<D4 / L21<17; The first lens group and the second lens group are coaxial and have a z-axis; The first lens group includes a first lens, a second lens, and a third lens coaxially arranged in sequence, the first lens is a cylindrical lens having negative toroidal power, the first lens has a distance L1 from an excitation surface of the wavelength conversion unit, and the L1, f1x, and f1y satisfy 0.7 1.1 The second lens group includes a fourth lens and a fifth lens coaxially arranged, the second lens group has a combined focal length f2, the wavelength conversion unit has a farthest distance L2 from an exit surface of the fifth lens, and the L2 and f2 satisfy 0.42 The second lens and the third lens are lenses having positive toroidal power, the fourth lens is a plano-convex lens having positive toroidal power, and the fifth lens is a plano-convex aspheric lens having positive toroidal power.

2. The optical system of claim 1, wherein The first lens has at least one concave surface in the x-axis direction, the first lens has a focal length f11x in the x-axis direction, and the f11x and f1x satisfy 1≤|f11x| / f1x≤8.

3. The optical system of claim 1, wherein The second lens has a convex surface with a radius of curvature R21 as an entrance surface and a flat surface as an exit surface, the second lens has an effective clear aperture D2, the second lens has a focal length f12, and the R21 and D2 satisfy 1.0≤|R21| / D2≤1.5 and f12>|f1y|.

4. The optical system of claim 1, wherein The third lens has a convex surface with a radius of curvature R31 as an entrance surface and a concave surface with a radius of curvature R32 as an exit surface, the third lens has an effective clear aperture D3, the third lens has a focal length f13, and the R31, R32, D3, and f13 satisfy |R31|*1.2 The third lens has a convex surface with a radius of curvature R31 as an entrance surface and a concave surface with a radius of curvature R32 as an exit surface, the third lens has an effective clear aperture D3, the third lens has a focal length f13, and the R31, R32, D3, and f13 satisfy |R31|*1.2 5. The optical system of claim 1, wherein The light receiving surface of the fourth lens facing the wavelength conversion unit is a plane, the light emitting surface of the fourth lens facing away from the wavelength conversion unit is a convex surface with a radius of curvature R42, and the effective light passing aperture of the fourth lens is D4, the R42 and D4 satisfy: 0.38≤|R42| / D4≤0.65; the focal length of the fourth lens is f21, 0.46 6. The optical system of claim 1, wherein The light receiving surface of the fifth lens facing the wavelength conversion unit is a plane, the light emitting surface of the fifth lens facing away from the wavelength conversion unit is a convex aspheric surface with an approximate spherical radius of curvature R52, and the effective light passing aperture of the fifth lens is D5, the R52 and D5 satisfy: 0.28≤|R52| / D5≤0.62; the focal length of the fifth lens is f22, 0.4 7. The optical system of claim 1, wherein The central thickness of the second lens is T2, and the T2 satisfies: 6<|R21| / T2<11; and / or, the central thickness of the fourth lens is T4, and the T4 satisfies: 1.1<|R42| / T4<1.6; wherein R21 is the radius of curvature of the light receiving surface of the second lens, and R42 is the radius of curvature of the light emitting surface of the fourth lens facing away from the wavelength conversion unit.

8. The optical system according to any one of claims 1 to 7, wherein A light uniformity diffusion sheet is further arranged between the first lens group and the wavelength conversion unit.

9. The optical system according to any one of claims 1 to 7, wherein The light source emitting excitation light is a laser light source, and the laser light source comprises n×m lasers, wherein n≥2 and m≥2.

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