Laser internal coaxial lens

Abstract

The utility model relates to the technical field of optical lenses, and provides a laser internal coaxial lens, which comprises a grating, a first lens, a second lens, a third lens, a fourth lens, a fifth lens and an image plane which are arranged in sequence, the first lens, the fourth lens and the fifth lens are all positive meniscus lenses, the second lens is a biconvex lens, the third lens is a biconvex lens, and the image plane is a biconvex lens. The third lens is a biconcave lens, and the second lens and the third lens form a sealed bonding lens. According to the technical scheme, the problem that an existing laser inner coaxial lens cannot adapt to some common working conditions due to the single model is solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to optical lens technical field, specifically, relate to a laser inner coaxial lens. BACKGROUND

[0002] The inner coaxial lens is an optical device designed to allow the light source, imaging system and detection system to share the same axis. This design is usually used to improve the imaging quality, especially in situations where precise control of the optical path and reduction of optical errors are required. The inner coaxial lens can be applied to various precision detection, measurement and laser processing systems. Among them, the laser inner coaxial lens is an optical component specially designed for laser processing systems.

[0003] The existing laser inner coaxial lens usually passes through a beam splitter or a specific optical element, so that the laser beam can be reflected along the same path while illuminating the target surface through the lens. This technology can ensure that the incident angle and the reflection angle of the laser are completely symmetrical, avoiding measurement or processing errors caused by angle errors. In the optical design of the laser inner coaxial lens, the focal length, numerical aperture, spot size, laser wavelength, distortion and other key parameters need to be considered. These optical parameters jointly determine the imaging quality, processing precision, system efficiency and adaptability of the lens. Limited by the above parameters, the existing laser inner coaxial lens is relatively small in number, and for many working conditions, the existing laser inner coaxial lens cannot provide good recognition effect.

[0004] Therefore, there is an urgent need for a new laser inner coaxial lens. UTILITY MODEL CONTENT

[0005] The utility model provides a kind of laser inner coaxial lens, solve the problem that the existing laser inner coaxial lens cannot adapt to some common working conditions due to single model.

[0006] The technical scheme of the utility model is as follows: a kind of laser inner coaxial lens, including grating, first lens, second lens, third lens, fourth lens, fifth lens and image plane which are sequentially arranged, the first lens, the fourth lens and the fifth lens are all positive meniscus lens, the second lens is double convex lens, the third lens is double concave lens, the second lens and the third lens form tightly bonded cemented lens.

[0007] As a further technical solution, the center distance between the grating and the front surface of the first lens is 80-100mm, the center distance between the back surface of the first lens and the front surface of the second lens is 0.2-88mm, the center distance between the back surface of the third lens and the front surface of the fourth lens is 0.2-2.3mm, the center distance between the back surface of the fourth lens and the front surface of the fifth lens is 2-2.2mm, and the center distance between the back surface of the fifth lens and the image plane is 25-29mm.

[0008] As a further technical solution, the front surface curvature radius of the first lens is -300±1mm, and the back surface curvature radius is -120±1mm; the front surface curvature radius of the second lens is 70±1mm, and the back surface curvature radius is -45±1mm; the front surface curvature radius of the third lens is -45±1mm, and the back surface curvature radius is 1000±1mm; the front surface curvature radius of the fourth lens is 40±1mm, and the back surface curvature radius is 240±1mm; the front surface curvature radius of the fifth lens is 29±1mm, and the back surface curvature radius is 15±1mm.

[0009] As a further technical solution, the refractive index of the first lens is 1.43, the dispersion coefficient is 94.5, and the effective aperture is 15±0.5mm; the refractive index of the second lens is 1.57, the dispersion coefficient is 56, and the effective aperture is 15±0.5mm; the refractive index of the third lens is 1.84, the dispersion coefficient is 24, and the effective aperture is 15±0.5mm; the refractive index of the fourth lens is 1.74, the dispersion coefficient is 45, and the effective aperture is 14.5±0.5mm; the refractive index of the fifth lens is 1.65, the dispersion coefficient is 34, and the effective aperture is 13±0.5mm.

[0010] As a further technical solution, the center thickness of the first lens is 11.5±0.2mm; the center thickness of the second lens is 6±0.5mm; the center thickness of the third lens is 8±0.5mm; the center thickness of the fourth lens is 10±0.5mm; and the center thickness of the fifth lens is 10±0.5mm.

[0011] The beneficial effects of the utility model are:

[0012] 1. In optical design, a relatively simple structure is adopted to realize the overall structure of the lens structure, and only five lenses are used to effectively improve the identification quality and image resolution, and the spacing between the lenses is changed to meet the requirements of different focal lengths and different numerical apertures.

[0013] 2. By designing the parameters of each lens itself and the combination of each lens, the system's light collection ability and resolution are enhanced. BRIEF DESCRIPTION OF DRAWINGS

[0014] The utility model will be described in further detail below in combination with the drawings and specific embodiments.

[0015] Figure 1 It is the optical path diagram corresponding to the second embodiment in the utility model;

[0016] Figure 2 It is the MTF modulation function diagram corresponding to the second embodiment;

[0017] Figure 3 It is the field curvature / distortion diagram corresponding to the second embodiment;

[0018] Figure 4 It is the optical path diagram corresponding to the second embodiment;

[0019] Figure 5 It is the optical path diagram corresponding to the third embodiment in the utility model;

[0020] Figure 6 It is the MTF modulation function diagram corresponding to the third embodiment;

[0021] Figure 7 It is the field curvature / distortion diagram corresponding to the third embodiment;

[0022] Figure 8 It is the optical path diagram corresponding to the third embodiment;

[0023] Figure 9 It is the cooperation logic diagram of the laser inner coaxial lens and other components provided by the utility model.

[0024] In the figure: 1, first lens; 2, second lens; 3, third lens; 4, fourth lens; 5, fifth lens; 6, grating; 7, image plane;

[0025] 11, object plane; 12, F-theta laser lens; 13, galvanometer; 14, laser; 15, laser inner coaxial lens; 16, camera; 17, half-transmission half-reflection mirror. DETAILED DESCRIPTION

[0026] The technical scheme in the embodiments of the utility model will be described clearly and completely below in combination with the embodiments of the utility model, and obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the person skilled in the art without creative labor are involved in the protection scope of the utility model.

[0027] Embodiment one,

[0028] As Figure 1 or Figure 5 shown, the embodiment provides a laser inner coaxial lens, which comprises a grating, a first lens, a second lens, a third lens, a fourth lens, a fifth lens and an image plane arranged in sequence, the first lens, the fourth lens and the fifth lens are all positive crescent lenses, the second lens is a double convex lens, the third lens is a double concave lens, and the second lens and the third lens form a tightly bonded cemented lens.

[0029] The laser inner coaxial lens has the following beneficial effects:

[0030] 1. In optical design, a relatively simple structure is adopted to realize the overall structure of the lens, and only five lenses are used to effectively improve the identification quality and image resolution, and meanwhile, the requirements of different focal lengths and different numerical apertures of multiple styles are met by changing the spacing between the lenses.

[0031] 2. The design of the parameters of the lenses and the combination of the lenses enhance the light collecting ability and resolution of the system.

[0032] Embodiment two,

[0033] As Figures 1-2 shown, on the basis of embodiment one, the embodiment provides the following content:

[0034] The center distance between the grating and the front surface of the first lens is 100mm, the center distance between the rear surface of the first lens and the front surface of the second lens is 0.2mm, the center distance between the rear surface of the third lens and the front surface of the fourth lens is 2.3mm, the center distance between the rear surface of the fourth lens and the front surface of the fifth lens is 2.2mm, and the center distance between the rear surface of the fifth lens and the image plane is 29mm.

[0035] The front surface curvature radius of the first lens is -300±1mm, and the rear surface curvature radius is -120±1mm; the front surface curvature radius of the second lens is 70±1mm, and the rear surface curvature radius is -45±1mm; the front surface curvature radius of the third lens is -45±1mm, and the rear surface curvature radius is 1000±1mm; the front surface curvature radius of the fourth lens is 40±1mm, and the rear surface curvature radius is 240±1mm; the front surface curvature radius of the fifth lens is 29±1mm, and the rear surface curvature radius is 15±1mm.

[0036] The first lens has a refractive index of 1.43, a dispersion coefficient of 94.5, and an effective aperture of 15±0.5mm; the second lens has a refractive index of 1.57, a dispersion coefficient of 56, and an effective aperture of 15±0.5mm; the third lens has a refractive index of 1.84, a dispersion coefficient of 24, and an effective aperture of 15±0.5mm; the fourth lens has a refractive index of 1.74, a dispersion coefficient of 45, and an effective aperture of 14.5±0.5mm; and the fifth lens has a refractive index of 1.65, a dispersion coefficient of 34, and an effective aperture of 13±0.5mm.

[0037] The first lens has a central thickness of 11.5±0.2mm; the second lens has a central thickness of 6±0.5mm; the third lens has a central thickness of 8±0.5mm; the fourth lens has a central thickness of 10±0.5mm; and the fifth lens has a central thickness of 10±0.5mm.

[0038] In this embodiment, the entrance pupil diameter is selected as D=10mm, the focal length is selected as f=60mm, and the numerical aperture is selected as NA=0.083.

[0039] Under the diffraction limit condition, the minimum diameter (spot size) of the light spot can be expressed by the following formula:

[0040] d=2λ / NA,

[0041] where d is the spot diameter, λ is the wavelength of the laser or light source, so the larger the NA, the smaller the spot diameter, and the higher the precision of laser processing or detection.

[0042] From Figures 2 to 4 It can be seen that the RMS spot radius is only 1.3μm, which meets the high precision requirement.

[0043] Example Three,

[0044] As Figures 1-2 shown, based on example one, the following contents are proposed in this embodiment:

[0045] The center distance between the grating and the front surface of the first lens is 80-100mm, the center distance between the back surface of the first lens and the front surface of the second lens is 0.2-88mm, the center distance between the back surface of the third lens and the front surface of the fourth lens is 0.2-2.3mm, the center distance between the back surface of the fourth lens and the front surface of the fifth lens is 2-2.2mm, and the center distance between the back surface of the fifth lens and the image plane is 25-29mm.

[0046] The front surface radius of curvature of the first lens is -300±1mm, the back surface radius of curvature is -120±1mm; the front surface radius of curvature of the second lens is 70±1mm, the back surface radius of curvature is -45±1mm; the front surface radius of curvature of the third lens is -45±1mm, the back surface radius of curvature is 1000±1mm; the front surface radius of curvature of the fourth lens is 40±1mm, the back surface radius of curvature is 240±1mm; the front surface radius of curvature of the fifth lens is 29±1mm, the back surface radius of curvature is 15±1mm.

[0047] The refractive index of the first lens is 1.43, the dispersion coefficient is 94.5, and the effective aperture is 15±0.5mm; the refractive index of the second lens is 1.57, the dispersion coefficient is 56, and the effective aperture is 15±0.5mm; the refractive index of the third lens is 1.84, the dispersion coefficient is 24, and the effective aperture is 15±0.5mm; the refractive index of the fourth lens is 1.74, the dispersion coefficient is 45, and the effective aperture is 14.5±0.5mm; the refractive index of the fifth lens is 1.65, the dispersion coefficient is 34, and the effective aperture is 13±0.5mm.

[0048] The central thickness of the first lens is 11.5±0.2mm; the central thickness of the second lens is 6±0.5mm; the central thickness of the third lens is 8±0.5mm; the central thickness of the fourth lens is 10±0.5mm; the central thickness of the fifth lens is 10±0.5mm.

[0049] In the embodiment, the entrance pupil diameter is selected as D=10mm, the focal length is selected as f=75mm, and the numerical aperture is selected as NA=0.067;

[0050] Under the diffraction limit condition, the minimum diameter (spot size) of the light spot can be expressed by the following formula:

[0051] d=2λ / NA,

[0052] Where d is the spot diameter, λ is the wavelength of the laser or light source, so the larger the NA, the smaller the spot diameter, and the higher the precision of laser processing or detection.

[0053] From Figures 6 to 8 It can be seen that the RMS spot radius is only 1.3μm, which meets the high precision requirement.

[0054] From Figure 9 It can be seen that the cooperation form of the laser inner coaxial lens with other components in the actual application. Among them, 11 is an object plane, 12 is an F-theta laser lens, 13 is a galvanometer, 14 is a laser, 15 is the laser inner coaxial lens provided by the utility model, 16 is a camera, and 17 is a half-mirror.

[0055] The above merely describes the preferred embodiments of the present application, and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A laser endo-coaxial lens characterized by, The grating (6), the first lens (1), the second lens (2), the third lens (3), the fourth lens (4), the fifth lens (5) and the image plane (7) are sequentially arranged, the first lens (1), the fourth lens (4) and the fifth lens (5) are positive meniscus lenses, the second lens (2) is a biconvex lens, the third lens (3) is a biconcave lens, and the second lens (2) and the third lens (3) form a tightly bonded cemented lens.

2. A laser internal coaxial lens according to claim 1, characterized in that, The center distance between the grating and the front surface of the first lens (1) is 80-100 mm; the center distance between the rear surface of the first lens (1) and the front surface of the second lens (2) is 0.2-88 mm; the center distance between the rear surface of the third lens (3) and the front surface of the fourth lens (4) is 0.2-2.3 mm; the center distance between the rear surface of the fourth lens (4) and the front surface of the fifth lens (5) is 2-2.2 mm; and the center distance between the rear surface of the fifth lens (5) and the image plane (7) is 25-29 mm.

3. The laser internal coaxial lens according to claim 1 or 2, characterized in that, The front surface of the first lens (1) has a curvature radius of -300±1 mm, and the rear surface has a curvature radius of -120±1 mm; the front surface of the second lens (2) has a curvature radius of 70±1 mm, and the rear surface has a curvature radius of -45±1 mm; the front surface of the third lens (3) has a curvature radius of -45±1 mm, and the rear surface has a curvature radius of 1000±1 mm; the front surface of the fourth lens (4) has a curvature radius of 40±1 mm, and the rear surface has a curvature radius of 240±1 mm; and the front surface of the fifth lens (5) has a curvature radius of 29±1 mm, and the rear surface has a curvature radius of 15±1 mm.

4. The laser internal coaxial lens according to claim 1 or 2, characterized in that, The first lens (1) has a refractive index of 1.43, a dispersion coefficient of 94.5, and an effective aperture of 15±0.5 mm; the second lens (2) has a refractive index of 1.57, a dispersion coefficient of 56, and an effective aperture of 15±0.5 mm; the third lens (3) has a refractive index of 1.84, a dispersion coefficient of 24, and an effective aperture of 15±0.5 mm; the fourth lens (4) has a refractive index of 1.74, a dispersion coefficient of 45, and an effective aperture of 14.5±0.5 mm; and the fifth lens (5) has a refractive index of 1.65, a dispersion coefficient of 34, and an effective aperture of 13±0.5 mm.

5. The laser internal coaxial lens according to claim 1 or 2, characterized in that, The first lens (1) has a center thickness of 11.5±0.2 mm; the second lens (2) has a center thickness of 6±0.5 mm; the third lens (3) has a center thickness of 8±0.5 mm; the fourth lens (4) has a center thickness of 10±0.5 mm; and the fifth lens (5) has a center thickness of 10±0.5 mm.

Images