CN117215076A

CN117215076A - Optical system

Info

Publication number: CN117215076A
Application number: CN202210625029.3A
Authority: CN
Inventors: 勾志勇; 请求不公布姓名
Original assignee: Guangzhou Guanglian Electronic Technology Co ltd
Current assignee: Guangzhou Guanglian Electronic Technology Co ltd
Priority date: 2022-06-02
Filing date: 2022-06-02
Publication date: 2023-12-12

Abstract

The invention discloses an optical system, which comprises a light source for emitting excitation light, a first lens group for gathering and/or focusing the excitation light, a wavelength conversion unit for converting the excitation light into illumination light, and a second lens group for gathering and/or collimating the illumination light; the beam quality product of the light source on the y-axis is smaller than the 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, the combined focal length of the first lens group in the y-axis direction is f1y, and the f1x and fly satisfy the following conditions: f1x/fly is more than or equal to 1.05 and less than or equal to 2.2. The optical system can well collect laser on the wavelength conversion unit and ensure the excitation effect, and can collect illumination light with high efficiency, thereby having excellent optical effect.

Description

Optical system

Technical Field

The present invention relates to the field of optical technology, and more particularly, to an optical system.

Background

The solid-state light source has been widely used in general illumination, special illumination and projection display directions due to the characteristics of long service life, energy saving, environmental protection and the like. Laser light is another emerging solid state light source following an LED, and one of the main ways in which laser light achieves illumination is by illuminating the laser light onto a wavelength conversion unit that converts the laser light into illumination light. In the case of a high-power laser module, a laser array formed by a plurality of lasers emits laser light, the laser light is converted into illumination light after being irradiated to a wavelength conversion unit, and then the illumination light is received by a light receiving module. However, the Beam quality product BPP (Beam-parameter product) of the laser light emitted by the laser array in the x y direction is usually unequal, so that the resulting laser spot is uneven in the xy direction, which affects the excitation of the wavelength conversion unit by the laser light. In order to concentrate energy and achieve good excitation effect, the light spot of the laser emitted by the laser array needs to be shaped. In addition, when the laser irradiates the fluorescent powder sheet type wavelength conversion unit, the laser emits light at an angle of 180 degrees basically, and if the laser cannot be well received, the brightness is obviously reduced, so that a light receiving module with a large Numerical Aperture (NA) is needed to be added for receiving the light so as to meet the brightness requirement.

Disclosure of Invention

The present invention has been made to overcome at least one of the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide an optical system that can collect laser light well on a wavelength conversion unit and ensure an excitation effect, and at the same time can collect illumination light with high efficiency, and is excellent in optical effect.

The technical scheme adopted by the invention is as follows:

an optical system includes a light source that emits excitation light, a first lens group that collects and/or focuses the excitation light, a wavelength conversion unit that converts the excitation light into illumination light, and a second lens group that collects and/or collimates the illumination light;

the beam quality product of the light source on the y-axis is smaller than the 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, the combined focal length of the first lens group in the y-axis direction is f1y, and the f1x and fly satisfy the following conditions: f1x/fly is more than or equal to 1.05 and less than or equal to 2.2;

the second lens group at least comprises a fourth lens with positive bending force, which is close to the wavelength conversion unit, wherein the effective clear aperture of the fourth lens is D4, the gap spacing between the fourth lens and the wavelength conversion unit is L21, and the D4 and L21 satisfy the following conditions: 13< D4/L21<17;

the first lens group and the second lens group are coaxial and are z-axis.

In one embodiment, the first lens group includes a first lens, a second lens and a third lens that are coaxially disposed in sequence, the first lens is a cylindrical lens with a negative bending force, a distance from a light incident surface of the first lens to an excited surface of the wavelength conversion unit is L1, and the L1, f1x, fly satisfy: l1/f1x is more than 0.7 and less than 1.4;1.1 < L1/f1y < 1.7.

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, and the f11x and flx satisfy: and f11 x/flx is more than or equal to 1 and less than or equal to 8.

In one embodiment, the second lens is a lens with positive bending force, the light incident surface is a convex surface, the curvature radius is R21, and the light emergent surface is a plane; the effective clear aperture of the second lens is D2, the focal length of the second lens is f12, and R21 and D2 satisfy the following conditions: R21/D2 is more than or equal to 1.0 and less than or equal to 1.5, and f12> |f1y|.

In one embodiment, the third lens is a lens with positive bending force, the light incident surface is convex and the curvature radius is R31, the light emergent surface is concave and the curvature radius is R32, the effective clear aperture of the third lens is D3, the focal length of the third lens is f13, and the R31, R32, D3, f13 satisfy: r31 is less than or equal to 1.2 < |R32 is less than or equal to |R31 is less than or equal to 2,0.45 is less than or equal to |R31/D3 is less than or equal to 0.82, and f13> |f1y|.

In one embodiment, the second lens group includes a fourth lens and a fifth lens coaxially disposed, the second lens group has a combined focal length of f2, the farthest distance from the excitation surface of the wavelength conversion unit to the light exit surface of the fifth lens is L2, and the L2 and f2 satisfy: 0.42 < f2/L2 < 0.65.

In one embodiment, the fourth lens is a plano-convex lens with positive bending force, a light receiving surface facing the wavelength conversion unit is a plane, a light emitting surface facing away from the wavelength conversion unit is a convex surface, and a curvature radius is R42, an effective clear aperture of the fourth lens is D4, and the R42 and D4 satisfy: R42/D4 is more than or equal to 0.38 and less than or equal to 0.65; the focal length of the fourth lens is f21, f2/f21 is more than 0.46 and less than 0.7,1.32, and f21/|R42| is more than or equal to 1.75.

In one embodiment, the fifth lens is a plano-convex aspheric lens with positive bending force, 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, the approximate spherical curvature radius of the light emitting surface is R52, the effective clear aperture of the fifth lens is D5, and the R52 and D5 satisfy: R52/D5 is more than or equal to 0.28 and less than or equal to 0.62; the focal length of the fifth lens is f22, f2/f22 is more than 0.4 and less than 0.85,1.35, and f22/|R52| is more than or equal to 1.82.

In one embodiment, the center thicknesses of the second lenses are respectively T2, and the T2 satisfies: 6< |R21|/T2<11; and/or, the center thickness of the fourth lens is respectively T4, and the T4 satisfies the following conditions: 1.1< |R42|/T4<1.6.

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

In one embodiment, the light source emitting excitation light is a laser light source comprising n×m lasers, where n is greater than or equal to 2 and m is greater than or equal to 2.

In one embodiment, the laser light source includes n×m laser chips and a plurality of collimating lenses disposed corresponding to the laser chips, and the n×m laser chips and the plurality of collimating lenses form a laser array. The laser emitted by the laser chip is 400-600 nm.

In one embodiment, the wavelength conversion unit is a fluorescent color wheel.

Compared with the prior art, the invention has the beneficial effects that: the invention uses the first lens group with a specific structure to collect/focus the excitation light, so that the BPP (business process planning) of the laser array in the x y direction is almost equal after the laser is collected and/or focused by the first lens group, a round laser spot can be obtained, the excitation efficiency of the wavelength conversion unit is high, and the invention uses the second lens group with a specific structure to collect/collimate the illumination light, thereby realizing the collection of the illumination light with large angle and high light collecting rate, high illumination and excellent optical effect.

Drawings

Fig. 1 is a schematic diagram of an optical system according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of an optical system in the x-z direction according to an embodiment of the present invention.

FIG. 3 is a schematic view of an optical system in the y-z direction according to an embodiment of the present invention.

Fig. 4 is a simulated analysis point chart of the first lens group of embodiment 1 of the present invention.

Fig. 5 is a simulated analysis phase difference chart of the first lens group in embodiment 1 of the present invention.

Fig. 6 is a simulated analysis point chart of the second lens group of embodiment 1 of the present invention.

Fig. 7 is a simulated analysis phase difference chart of the second lens group of embodiment 1 of the present invention.

Fig. 8 is an optical simulation of embodiment 1 of the present invention.

Fig. 9 is an optical simulation of example 1 without the first lens.

Fig. 10 is a simulated analysis point chart of the first lens group of embodiment 2 of the present invention.

Fig. 11 is a simulated analysis phase difference diagram of the first lens group in embodiment 2 of the present invention.

Fig. 12 is a simulated analysis point chart of the second lens group of embodiment 2 of the present invention.

Fig. 13 is a simulated analysis phase difference chart of the second lens group of embodiment 2 of the present invention.

Fig. 14 is an optical simulation of embodiment 2 of the present invention.

Fig. 15 is an optical simulation of comparative example 2 without the first lens.

Fig. 16 is a simulated analysis point chart of the first lens group of embodiment 3 of the present invention.

Fig. 17 is a simulated analysis phase difference diagram of the first lens group in embodiment 3 of the present invention.

Fig. 18 is a simulated analysis point chart of the second lens group of embodiment 3 of the present invention.

Fig. 19 is a simulated analysis phase difference chart of the second lens group of embodiment 3 of the present invention.

FIG. 20 is a simulated analysis point chart of the optical system of example 3 of the present invention.

Fig. 21 is an optical simulation of comparative example 3 without the first lens.

Description of the drawings: 10. a first lens group; 11. a first lens; a second lens; 13. a third lens; 20. a second lens group; 21. a fourth lens; 22. a fifth lens; 30. a wavelength conversion unit; 40. a light source; a 41 laser chip; 42. a collimating lens; 50. a light-homogenizing diffusion sheet; 60 light-emitting lenses.

Detailed Description

The drawings are for illustrative purposes only and are not to be construed as limiting the invention. For better illustration of the following embodiments, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the actual product dimensions; it will be appreciated by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

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 generally unequal, so that the resulting laser spot is uneven in the x y direction, and the excitation efficiency of the laser is affected. In addition, after the laser is excited, part of the laser can be converted into laser, and illumination light can be formed after the excited laser and the un-excited laser are mixed, but the conventional light receiving component for collecting the illumination light is usually small in numerical aperture and low in light receiving efficiency, so that the luminous flux and the illumination intensity of the illumination light are insufficient.

Based on the above, the technical scheme of the invention is provided.

In one embodiment of the present invention, an optical system includes a light source that emits 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 beam quality product of the light source on the y-axis is smaller than the 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, the combined focal length of the first lens group in the y-axis direction is f1y, and the f1x and fly satisfy the following conditions: f1x/fly is more than or equal to 1.05 and less than or equal to 2.2; the second lens group at least comprises a fourth lens with positive bending force, which is close to the wavelength conversion unit, wherein the effective clear aperture of the fourth lens is D4, the gap spacing between the fourth lens and the wavelength conversion unit is L21, and the D4 and L21 satisfy the following conditions: 13< D4/L21<17; the first lens group and the second lens group are coaxial and are z-axis.

The optical system provided by the invention can perform high-efficiency optical processing on different excitation lights of the BPP in the x y direction to obtain illumination light with excellent optical efficiency, wherein the cylindrical lens is arranged in the first lens group, and the combined focal length of the first lens group in the x and y directions is controlled to realize optical shaping of the excitation light to obtain circular light spots, so that the energy density of the light spots focused on the wavelength conversion unit is high, and the excitation efficiency is high. By controlling the distance between the fourth lens and the wavelength conversion unit in the second lens group 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 receiving rate of the second lens group is high, and the light receiving efficiency of the whole optical system is effectively improved.

In any embodiment, the ratio of the beam quality product of the light source on the y-axis to the beam quality product on the x-axis is 0.5-0.9.

In any embodiment, the f1x, fly satisfy: f1x/fly is more than or equal to 1.1 and less than or equal to 2. Still further, the f1x, fly satisfy: f1x/fly is more than or equal to 1.14 and less than or equal to 1.8.

In any embodiment, the D4, L21 satisfies: D4/L21 is more than or equal to 14 and less than or equal to 16. Still further, the D4, L21 satisfies: D4/L21 is more than or equal to 14 and less than or equal to 15.

In any embodiment, the first lens group includes a first lens, a second lens and a third lens that are coaxially disposed in sequence, the first lens is a cylindrical lens with a negative bending force, a distance from a light incident surface of the first lens to an excited surface of the wavelength conversion unit is L1, and the L1, f1x, fly satisfy: l1/f1x is more than 0.7 and less than 1.4;1.1 < L1/f1y < 1.7.

In this embodiment, the first lens in the first lens group is a cylindrical lens with a negative bending force, which is used to better correct the BPP of the excitation light in the x and y directions, and further controls the ratio of the combined focal length f1y to L1 of the first lens group in the y axis direction and the ratio of the combined focal length f1x to L1 of the first lens group in the x axis direction, so that the overall size of the first lens group is small and the structure is compact.

In any embodiment, the L1, f1x, fly satisfies: l1/f1x is more than or equal to 0.9 and less than or equal to 1.24; l1/f1y is more than or equal to 1.4 and less than or equal to 1.5

In any 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, and the f11x and flx satisfy the following conditions: and f11 x/flx is more than or equal to 1 and less than or equal to 8.

In any embodiment, the f11x and flx satisfy: and f11 x/flx is more than or equal to 1.77 and less than or equal to 7.2.

In any embodiment, the second lens is a lens with positive bending force, the light incident surface is a convex surface, the curvature radius is R21, and the light emergent surface is a plane; the effective clear aperture of the second lens is D2, the focal length of the second lens is f12, and R21 and D2 satisfy the following conditions: R21/D2 is more than or equal to 1.0 and less than or equal to 1.5, and f12> |f1y|.

The second lens is used for further focusing the light which is further gathered/focused by the first lens and reducing the size of the light gathering system.

In any embodiment, 1.18.ltoreq.R21|/D2.ltoreq.1.23.

In any embodiment, the third lens is a lens with positive bending force, the light incident surface is convex and the curvature radius is R31, the light emergent surface is concave and the curvature radius is R32, the effective clear aperture of the third lens is D3, the focal length of the third lens is f13, and the R31, R32, D3, f13 satisfy: and R31 is less than or equal to 1.2 < |R32 is less than or equal to |R31 is less than or equal to 2,0.45 is less than or equal to 0.82, and f13> |f1y|.

The third lens can well correct aberration and shorten the focal length of the first lens group by adopting the lens, so that the focusing effect of the first lens group is ensured.

In any embodiment, the R31, R32, D3, f13 satisfies: and R31 is less than or equal to 1.64 is less than or equal to R32 is less than or equal to R31 is less than or equal to 1.66, and 0.63 is less than or equal to R31/D3 is less than or equal to 0.68.

In any embodiment, the second lens group includes a fourth lens and a fifth lens coaxially disposed, a combined focal length of the second lens group is f2, a farthest distance from an excitation surface of the wavelength conversion unit to a light exit surface of the fifth lens is L2, and the L2 and f2 satisfy: 0.42 < f2/L2 < 0.65. The size of the second lens group can be further reduced by controlling the ratio of L2 to f2, so that the whole structure of the optical system is compact.

In any embodiment, 0.52.ltoreq.f2/L2.ltoreq.0.54.

In any embodiment, the fourth lens is a plano-convex lens with positive bending force, a light receiving surface facing the wavelength conversion unit is a plane, a light emitting surface facing away from the wavelength conversion unit is a convex surface, and a curvature radius is R42, an effective clear aperture of the fourth lens is D4, and the R42 and D4 satisfy: R42/D4 is more than or equal to 0.38 and less than or equal to 0.65; the focal length of the fourth lens is f21, f2/f21 is more than 0.46 and less than 0.7,1.32, and f21/|R42| is more than or equal to 1.75.

In any embodiment, the R42 and D4 satisfy: R42/D4 is more than or equal to 0.51 and less than or equal to 0.54.

In any embodiment, the 0.57.ltoreq.f2/f21.ltoreq. 0.59,1.52.ltoreq.f21/|R42|.ltoreq.1.54.

In any embodiment, the fifth lens is a plano-convex aspheric lens with positive bending force, 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, the approximate spherical curvature radius of the light emitting surface is R52, the effective clear aperture of the fifth lens is D5, and the R52 and D5 satisfy: R52/D5 is more than or equal to 0.28 and less than or equal to 0.62; the focal length of the fifth lens is f22, f2/f22 is more than 0.4 and less than 0.85,1.35, and f22/|R52| is more than or equal to 1.82.

In any embodiment, the 0.39+|R52|/D5+.0.4; f2/f22 is more than or equal to 0.62 and less than or equal to 0.64,1.52, and f22/|R52| is more than or equal to 1.54.

The fourth lens is used for gathering illumination light at the maximum angle, and the fifth lens is used for reducing the total optical length as much as possible, correcting aberration and ensuring collimation.

In any embodiment, the center thicknesses of the second lenses are T2, and T2 satisfies: 6< R21/T2<11; and/or, the center thickness of the fourth lens is respectively T4, and the T4 satisfies the following conditions: 1.1< |R42|/T4<1.6.

In any embodiment, 7.ltoreq.R21|/T2.ltoreq.11.

In any embodiment, 1.3.ltoreq.R42|/T4.ltoreq.1.4.

In any embodiment, the gap spacing of the wavelength conversion unit and the fourth lens, and the gap spacing of the fourth lens and the fifth lens are L21, L22, respectively, the L21 and L22 satisfying: 2.8 x l22< l21<5.2 x l22.

In any embodiment, 3.7×l22.ltoreq.l21.ltoreq.4.5×l22.

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

In any embodiment, the light source emitting excitation light is a laser light source comprising n×m lasers, where n is greater than or equal to 2 and m is greater than or equal to 2.

In any embodiment, the light source comprises a plurality of n×m laser chips and a plurality of collimating lenses arranged corresponding to the laser chips, and the n×m laser chips and the plurality of collimating lenses form a laser array. The laser emitted by the laser chip is 400-600 nm.

In any embodiment, the wavelength conversion unit is a fluorescent color wheel. Further, the fluorescent color wheel is a transmission fluorescent color wheel. Further, the fluorescent color wheel comprises a transmission type fluorescent color sheet and a driving mechanism for driving the transmission type fluorescent color sheet to rotate.

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 materials is as follows: nd is more than 1.45 and less than 1.88.

Further details are provided below in connection with specific parameters.

The light incident surfaces in the following embodiments all refer to surfaces close to the light source, the light emergent surfaces in the following embodiments all refer to surfaces back to the light source, and the light receiving surfaces in the following embodiments all refer to surfaces close to the wavelength conversion unit.

Example 1

As shown in fig. 1, 2, and 3, the present embodiment discloses an optical system including a light source 40 that emits 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;

the beam quality product of the light source 40 in the y-axis is smaller than the beam quality product in the x-axis;

the first lens group and the second lens group are coaxial and are z-axis.

Specifically, in this embodiment, the beam quality product of the light source on the y-axis is BPPy, and the ratio of the beam quality products on the x-axis is BPPx, bpp0=bppy/bppx=0.86. A combined focal length f1x=13.3 mm in the x-axis direction, a combined focal length f1y=11.7mm in the y-axis direction, and f1x/fly=1.14 of the first lens group;

the effective clear aperture of the fourth lens is d4=19.5 mm, the gap spacing between the fourth lens and the wavelength conversion unit is l21=1.3mm, and d4/l21=15.

Further, in this embodiment, the first lens group includes a first lens, a second lens, and a third lens that are coaxially disposed in order, where the first lens is a cylindrical lens with a negative bending force, and at least one surface of the first lens in the x-axis direction is concave. Specifically, as shown in fig. 1, 2 and 3, the present embodiment takes the light incident surface as a plane, the light emergent surface as a plane in the y-axis direction, and the concave surface as a concave surface in the x-axis direction as an example. In other embodiments, the light incident surface may be a plane in the y-axis direction, a concave surface in the x-axis direction, a plane on the light emergent surface, or a concave surface in the x-axis direction. The second lens is a lens with positive bending force, the light incident surface is a convex surface, and the light emergent surface is a plane. The third lens is a lens with positive bending force, the light incident surface is a convex surface, and the light emergent surface is a concave surface.

Further, in the present embodiment, the second lens group includes a fourth lens and a fifth lens coaxially disposed. The fourth lens is a plano-convex lens with positive bending force, the light receiving surface facing the wavelength conversion unit is a plane, and the light receiving surface facing away from the wavelength conversion unit is a light emitting surface. The fifth lens is a plano-convex aspheric lens with positive bending force, the light receiving surface facing the wavelength conversion unit is a plane, and the light emitting surface facing away from the wavelength conversion unit is a convex aspheric surface.

Specifically, in the embodiment, the radius of curvature of the light incident surface of the first lens is R11, the radius of curvature of the light emergent surface in the y-axis direction is R12y, the radii of curvature of the light incident surface and the light emergent surface of the second lens are R21 and R22, the radii of curvature of the light incident surface and the light emergent surface of the third lens are R31 and R32, the radii of curvature of the light incident surface and the light emergent surface of the fourth lens are R41 and R42, and the radii of curvature of the light incident surface and the light emergent surface of the fifth lens are R51 and R52 (R52 is an approximately spherical radius of curvature). The effective clear apertures of the first lens, the second lens, the third lens, the fourth lens and the fifth lens are respectively D1, D2, D3, D4 and D5, and the central thicknesses of the first lens, the second lens, the third lens, the fourth lens and the fifth lens are respectively T1, T2, T3, T4 and T5. The parameters of each lens of this example are shown in table 1.

TABLE 1

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 emergent surface of the wavelength conversion unit to the light emergent surface of the fifth lens is L2, the gap spacing between the first lens and the second lens, the gap spacing between the second lens and the third lens are L12 and L13, respectively, and the gap spacing between the fourth lens and the fifth lens is L22, respectively. Specifically, in the present embodiment, l1=16.5 mm, l2=16.58 mm, l12=1 mm, l13=0.3 mm, l22=0.3 mm.

Further, in the present embodiment, 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.

Further, in the present embodiment, the depth z of the aspherical surface of the light exit surface of the fifth lens satisfies:

wherein alpha is ₁ ＝α ₆ ＝α ₇ ＝α ₈ ＝0；

k＝-0.7，α ₂ ＝-2e ^-6 ，α ₃ ＝-2.5e ^-7 ，α ₄ ＝1.56e ^-8 ，α ₅ ＝-5.3e ^-11 ；

c is 1/R, R is the radius of curvature, and k is the quadric surface coefficient; r is the height. Alpha ₁ To alpha ₈ Is an aspherical coefficient.

Further, in this embodiment, the gap pitches of the first lens and the second lens and the gap pitches of the second lens and the third lens are L12, L13, l12=1 mm, l13=0.3 mm, respectively.

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

Further, the light source for emitting the excitation light is a laser light source, and the laser light source comprises n multiplied by m lasers, wherein n is more than or equal to 2, and m is more than or equal to 2. As shown in fig. 2 and 3, the present embodiment takes a laser array with a laser light source of 4×2 as an example, and in other implementations, other number of laser arrays are also possible, so long as the ratio of the product of the beam quality on the y-axis to the product of the beam quality on the x-axis emitted by the laser array is about 0.87.

Further, the laser light source comprises 4×2 laser chips and 4×2 collimating lenses corresponding to the laser chips, and the 4×2 laser chips and the 4×2 collimating lenses form a laser array. The laser emitted by the laser chip is 400-600 nm.

Further, in this 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 comprises a transmission type fluorescent color sheet and a driving mechanism for driving the transmission type fluorescent color sheet to rotate. The fluorescent color wheel may be of a conventional structure in the market, and will not be described in detail herein.

Further, in this 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: nd is more than 1.45 and less than 1.88.

As shown in fig. 4, in the point column diagram of the first lens group of the optical system described in embodiment 1 after the light source is folded and/or focused, as can be seen from fig. 4, the optical system described in the embodiment can obtain a nearly circular laser spot through the first lens group, and RMS radius is about 21.6 μm at the maximum, so that the focused spot can be better through the first lens group, and the spot focusing effect is good. As shown in fig. 5, the aberration curve of the first lens group shows that the maximum scale of the focused spot is ±50μm from fig. 5, indicating that the aberration of the focused spot is small.

As shown in fig. 6, the spot diagram of the second lens group is based on a numerical aperture of 0.97, and as can be seen from fig. 6, the collimated light spot RMS radius is about 10.8 μm at the maximum, and the collimation effect of the second lens group is good. As shown in fig. 7, the aberration curve of the second lens group is shown in fig. 7, and the maximum scale of the collimated light spot is ±50μm, which indicates that the aberration of the collimated light spot is small.

As can be seen from fig. 8 (simulation distance is 20 m), the final optical simulation of the optical system according to the present embodiment shows that the optical system according to the present embodiment has a circular spot effect and a maximum illuminance of 8.32×10 ⁴ lux. When the first lens is not used, the optical simulation is as shown in FIG. 9, and as can be seen from FIG. 9, the light spot effect is ellipsoidal, and the maximum illuminance at the center is 7.4X10 ⁴ The present embodiment uses the first lens to increase the center maximum illuminance by about 12.4%.

Further, as shown in fig. 1, the optical system of this embodiment further includes an optical lens, and the size and specification of the optical lens may be adjusted or changed accordingly due to different requirements of the downstream product end, which is not described herein.

Example 2

As shown in fig. 1, 2 and 3, the present embodiment discloses an optical system including a light source 40 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, as shown in fig. 1, 2 and 3; the beam quality product of the light source 40 in the y-axis is smaller than the beam quality product in 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, the combined focal length of the first lens group in the y-axis direction is f1y, and the f1x and fly satisfy the following conditions: f1x/fly is more than or equal to 1.05 and less than or equal to 2.2; the second lens group at least comprises a fourth lens with positive bending force, which is close to the wavelength conversion unit, wherein the effective clear aperture of the fourth lens is D4, the gap spacing between the fourth lens and the wavelength conversion unit is L21, and the D4 and L21 satisfy the following conditions: 13< D4/L21<17; the first lens group and the second lens group are coaxial and are z-axis.

The overall structure and operation principle of the optical system described in this embodiment 2 are substantially the same as those of embodiment 1, except that specific parameters are slightly changed. The parameters of this example 2 are as follows:

bpp0=0.54, f1x=23.8, fly=13.2, f1x/fly=1.8, f12=27.1 mm, f13=27.4 mm, f21=17.5 mm, f22=16.3 mm, f2=10.1 mm, l1=18.9 mm, l12=1.15 mm, l13=0.3 mm, l2=19.1 mm, l21=1.5 mm, l22=0.4 mm. The parameters of each lens are shown in table 2.

TABLE 2

wherein alpha is ₁ ＝α ₆ ＝α ₇ ＝α ₈ ＝0；

k＝-0.72，α ₂ ＝-1.392e ^-6 ，α ₃ ＝-1.28e ^-7 ，α ₄ ＝5.74e ^-9 ，α ₅ ＝-1.51e ^-11 ；

Other structures and working principles of this embodiment are the same as those of embodiment 1, and will not be described here again.

As shown in fig. 10, in a point chart of the first lens group of the optical system described in embodiment 2 after the light source is folded and/or focused, as can be seen from fig. 10, the optical system described in embodiment 2 can obtain a nearly circular laser spot through the first lens group, and RMS radius is about 25.2 μm at maximum, so that the focused spot can be better through the first lens group, and the spot focusing effect is good. As shown in fig. 11, the aberration curve of the first lens group shows that the maximum scale of the focused spot is ±50μm, indicating that the spot aberration after focusing is small, as seen from fig. 11.

As shown in fig. 12, which is a point chart of the second lens group based on the numerical aperture of 0.97, the collimated light spot RMS radius is about 13 μm, and it is seen that the second lens group has a good collimation effect. As shown in fig. 13, the aberration curve of the second lens group is shown in fig. 13, and the maximum scale of the collimated light spot is ±50μm, which indicates that the aberration of the collimated light spot is small.

The final optical simulation of the optical system described in this example 2 is shown in FIG. 14 (modeAs can be seen from fig. 14, the optical system according to the present embodiment finally shows a circular spot effect with a maximum illuminance of 7.71×10 at the center ⁴ lux. When the first lens is not used. As shown in FIG. 15, the optical simulation is that the light spot effect is ellipsoidal and the maximum illuminance at the center is 4.29×10 as shown in FIG. 15 ⁴ The maximum illuminance at the center of the rear of the first lens is improved by about 79.7% in the embodiment.

Example 3

BPP0＝0.64，f1x＝23.7mm，fly＝15.5mm，f1x/fly＝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。

the parameters of each lens are shown in table 3.

TABLE 3 Table 3

Further, in this embodiment, the aspherical depth Z of the light exit surface of the third lens satisfies:

wherein alpha is ₁ ＝α ₆ ＝α ₇ ＝α ₈ ＝0；

k＝-0.72，α ₂ ＝-9.15e ^-7 ，α ₃ ＝-6.36e ^-8 ，α ₄ ＝2.1e ^-9 ，α ₅ ＝-4.3e ^-12 ；

Other structures of this embodiment are the same as those of embodiment 1, and will not be described here again.

As shown in fig. 16, the spot diagram of the first lens group of the optical system in embodiment 3 after the light source is folded and/or focused is shown in fig. 16, it can be seen from fig. 16 that the optical system in the embodiment can obtain a nearly circular laser spot through the first lens group, and RMS radius is about 26.3 μm at the maximum, so that the focused spot can be better through the first lens group, and the spot focusing effect is good. As shown in fig. 17, the aberration curve of the first lens group shows that the maximum scale of the focused spot is ±50μm, indicating that the spot aberration after focusing is small, as shown in fig. 17.

As shown in fig. 18, the spot diagram of the second lens group is based on a numerical aperture of 0.97, and as can be seen from fig. 18, the collimated light spot RMS radius is about 12.5 μm at the maximum, and the collimation effect of the second lens group is good. As shown in fig. 19, the aberration curve of the second lens group is shown in fig. 19, and the maximum scale of the collimated light spot is ±50μm, indicating that the aberration of the collimated light spot is small.

Described in this example 3As shown in fig. 20 (simulation distance 20 m), the final optical simulation of the optical system shows that the optical system according to the present embodiment finally shows a circular spot effect and a maximum illuminance at the center of 8.4×10 as shown in fig. 20 ⁴ lux. When the first lens is not used. As shown in FIG. 21, the optical simulation is that the light spot effect is ellipsoidal and the maximum illuminance at the center is 5.93×10 as shown in FIG. 21 ⁴ The present embodiment uses the first lens to increase the center maximum illuminance by about 41.7%.

It should be understood that the foregoing examples of the present invention are merely illustrative of the present invention and are not intended to limit the present invention to the specific embodiments thereof. Any modification, equivalent replacement, improvement, etc. that comes within the spirit and principle of the claims of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An optical system comprising a light source for 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 first lens group and the second lens group are coaxial and are z-axis.

2. The optical system of claim 1, wherein the first lens group includes a first lens, a second lens, and a third lens coaxially arranged in this order, the first lens is a cylindrical lens having a negative bending force, a distance from a light incident surface of the first lens to an excited surface of the wavelength conversion unit is L1, and the L1, f1x, fly satisfy: l1/f1x is more than 0.7 and less than 1.4;1.1 < L1/f1y < 1.7.

3. The optical system of claim 2, wherein 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, and the f11x and flx satisfy: and f11 x/flx is more than or equal to 1 and less than or equal to 8.

4. The optical system of claim 2, wherein the second lens is a lens with positive bending force, the light incident surface is convex and the curvature radius is R21, and the light emergent surface is plane; the effective clear aperture of the second lens is D2, the focal length of the second lens is f12, and R21 and D2 satisfy the following conditions: R21/D2 is more than or equal to 1.0 and less than or equal to 1.5, and f12> |f1y|.

5. The optical system of claim 2, wherein the third lens is a lens having a positive bending force, the light incident surface is convex and the radius of curvature is R31, the light emergent surface is concave and the radius of curvature is R32, the effective clear aperture of the third lens is D3, the focal length of the third lens is f13, and the R31, R32, D3, f13 satisfy: and R31 is less than or equal to 1.2 < |R32 is less than or equal to |R31 is less than or equal to 2,0.45 is less than or equal to 0.82, and f13> |f1y|.

6. The optical system according to claim 1, wherein the second lens group includes a fourth lens and a fifth lens coaxially disposed, a combined focal length of the second lens group is f2, a farthest distance from an excitation surface of the wavelength conversion unit to a light exit surface of the fifth lens is L2, and the L2 and f2 satisfy: 0.42 < f2/L2 < 0.65.

7. The optical system of claim 6, wherein the fourth lens is a plano-convex lens having a positive bending force, a light receiving surface facing the wavelength conversion unit is a plane, a light emitting surface facing away from the wavelength conversion unit is a convex surface and has a radius of curvature R42, an effective clear aperture of the fourth lens is D4, and the R42 and D4 satisfy: R42/D4 is more than or equal to 0.38 and less than or equal to 0.65; the focal length of the fourth lens is f21, f2/f21 is more than 0.46 and less than 0.7,1.32, and f21/|R42| is more than or equal to 1.75.

8. The optical system of claim 6, wherein the fifth lens is a plano-convex aspheric lens having a positive bending force, a light receiving surface thereof facing the wavelength conversion unit is a plane, a light emitting surface thereof facing away from the wavelength conversion unit is a convex aspheric surface and has an approximate spherical radius of curvature of R52, an effective clear aperture of the fifth lens is D5, and the R52 and D5 satisfy: R52/D5 is more than or equal to 0.28 and less than or equal to 0.62; the focal length of the fifth lens is f22, f2/f22 is more than 0.4 and less than 0.85,1.35, and f22/|R52| is more than or equal to 1.82.

9. The optical system of claim 1, wherein the second lenses each have a center thickness T2, the T2 satisfying: 6< |R21|/T2<11; and/or, the center thickness of the fourth lens is respectively T4, and the T4 satisfies the following conditions: 1.1< |R42|/T4<1.6.

10. The optical system according to any one of claims 1 to 9, wherein a light homogenizing diffusion sheet is further provided between the first lens group and the wavelength conversion unit.

11. An optical system according to any one of claims 1 to 9, wherein the light source emitting excitation light is a laser light source comprising n x m lasers, where n is ≡2 and m is ≡2.