Improved linear laser module

Abstract

The utility model discloses an improved linear laser module, relates to the technical field of laser high-precision detection, and is mainly used for solving the problems that the conventional linear laser module often neglects the influence of astigmatism in an optical system, so that the energy is greatly attenuated, and the energy loss is caused. The main structure of the device is that the device comprises a laser diode, a biconical lens, a linear beam focusing lens, a Powell prism, a linear beam collimating lens group, a near-end receiving screen and a far-end receiving screen which are sequentially arranged along the direction of an optical axis. The utility model provides an improved linear laser module, which eliminates the influence of astigmatism of a laser diode, and collimates and shapes light beams output by the laser diode into linear laser in a high-precision and high-quality manner, thereby avoiding great attenuation and loss of energy.

Description

Technical Field

[0001] The utility model relates to the technical field of laser high-precision detection, in particular to an improved linear laser module. Background Art

[0002] With the rapid development of industrial technology, non-contact optical detection and 3D reconstruction have gradually become key technologies in the industrial field. Among them, the solution based on optical images has attracted the attention of technicians due to its cost advantage, high efficiency and convenience. In order to improve the measurement accuracy of image acquisition, a fine laser line with high energy density and uniform energy distribution within the required range is essential.

[0003] In existing linear laser modules, laser diodes are the most commonly used laser sources, and Powell prisms are currently the most commonly used and most effective linear laser generators. Among them, Powell prisms have extremely high requirements for the incident light beam - if the incident light beam size is inconsistent with the beam size set by the Powell prism, it will cause uneven energy distribution of the linear light beam, and the collimation of the incident light beam will also affect the quality of the linear light beam. Therefore, an aspheric collimating lens is often set on the light incident side of the Powell prism to ensure the collimation of the incident light beam. But if Figure 1 The astigmatism diagram of the output beam of the laser diode is shown in the figure. The divergence angle of the laser diode is not symmetrically distributed along the optical axis. At the same time, due to the light-emitting characteristics of the laser diode, the light-emitting points along the fast axis and slow axis of the laser diode do not intersect, but there is a certain distance in the direction of the optical axis - this distance is the astigmatism.

[0004] However, the linear laser modules on the market often ignore the effect of astigmatism in the optical system and treat the laser diode as an ideal point light source for subsequent optical design, which leads to a significant attenuation of energy and energy loss - such as Figure 2 The optical path of a laser diode light source with astigmatism passing through an aspheric collimating lens is shown in the figure (since this aspheric collimating lens is symmetrical about the optical axis, the beam shaping of the laser fast axis and slow axis is placed on the same section). When the light-emitting point of the fast-axis beam is placed at the focus of the aspheric collimating lens, the fast-axis beam is collimated and the light-emitting point of the slow-axis beam is far away from the focus of the aspheric lens. At this time, the slow-axis beam converges and emits. After a period of free transmission, it focuses to a point and then diverges rapidly. Similarly, if the focus of the aspheric collimating lens is moved to the light-emitting point of the slow-axis beam, the slow-axis beam is collimated and the fast-axis beam is emitted in a divergent state. Utility Model Content

[0005] The utility model aims to provide an improved linear laser module, which eliminates the influence of the astigmatism of the laser diode and collimates and shapes the light beam output by the laser diode into a linear laser with high precision and high quality, thereby avoiding significant attenuation and loss of energy.

[0006] The technical solution of the utility model to solve the above technical problems is: an improved linear laser module, comprising a laser diode, a biconical lens, a linear beam focusing lens, a Powell prism, a linear beam collimating lens group, a near-end receiving screen, and a far-end receiving screen arranged in sequence along the light output axis direction;

[0007] The surface formula of the biconical lens is:

[0008]

[0009] Among them, k x is the cone coefficient of the biconical lens in the x direction; k y is the cone coefficient of the biconical lens in the y direction; c x is the curvature of the biconical lens in the x direction; c y is the curvature of the biconical lens in the y direction; x, y, z are the coordinate values ​​of a point on the biconical lens.

[0010] As a further improvement of the present invention, the diameter of the Powell prism is 6 mm-15 mm, and the fan angle is 30°-110°.

[0011] As a further improvement of the present invention, the major axis of the elliptical light beam emitted by the laser diode is perpendicular to the ridge of the Powell prism.

[0012] As a further improvement of the present invention, the linear beam focusing lens is a plano-convex aspherical cylindrical lens with positive optical power.

[0013] As a further improvement of the present invention, the focal length of the linear light beam focusing lens is 50mm-300mm.

[0014] As a further improvement of the present invention, the linear beam collimating lens group includes at least two parallel plano-convex aspheric lenses.

[0015] As a further improvement of the present invention, the focal length of the plano-convex aspheric lens is 10 mm-50 mm.

[0016] As a further improvement of the present invention, the wavelength of the laser diode is 400nm-700nm.

[0017] Beneficial Effects

[0018] Compared with the prior art, the advantages of an improved linear laser module of the utility model are:

[0019] 1. Compared with the existing linear laser module, this device eliminates the influence of the astigmatism of the laser diode, and collimates and shapes the light beam output by the laser diode into a linear laser with high precision and high quality, thereby avoiding significant energy attenuation and loss, effectively improving the beam quality of the laser line, and thus improving the laser detection accuracy.

[0020] 2. The device can collimate and focus the laser beams in the fast and slow axis directions, independently and without interfering with each other, so as to obtain parallel line lasers with uniform energy distribution, long focal depth, and line width that meet the requirements of high-precision optical measurement. Compared with ordinary line lasers, the camera reception efficiency of parallel line lasers on strongly reflective planes (such as metals, ceramics, etc.) is greatly improved.

[0021] The present invention will become more clear through the following description in conjunction with the accompanying drawings, which are used to explain the embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 Schematic diagram of the astigmatism of the output beam of the laser diode;

[0024] Figure 2 This is the collimation optical path diagram of the aspheric collimating lens to the laser diode;

[0025] Figure 3 This is the optical path diagram of the laser diode fast axis beam passing through the biconical lens;

[0026] Figure 4 This is the optical path diagram of the laser diode slow axis beam passing through the biconical lens;

[0027] Figure 5 This is a light path trajectory diagram of the utility model in the laser fast axis direction;

[0028] Figure 6 This is a light path trajectory diagram of the utility model in the direction of the laser slow axis.

[0029] Among them: 1-laser diode; 2-biconical lens; 3-linear beam focusing lens; 4-Powell prism; 5-linear beam collimating lens group; 6-near-end receiving screen; 7-far-end receiving screen. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; of course, it can also be a mechanical connection or an electrical connection; in addition, it can also be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] Embodiments of the present invention will now be described with reference to the accompanying drawings.

[0033] Example

[0034] The specific implementation of the utility model is as follows Figure 3-6 As shown, an improved linear laser module includes a laser diode 1, a biconical lens 2, a linear beam focusing lens 3, a Powell prism 4, a linear beam collimating lens group 5, a near-end receiving screen 6, and a far-end receiving screen 7, which are arranged in sequence along the light-emitting axis. Specifically, the laser diode 1 is used to emit a laser beam; the biconical lens 2 is used to collimate the emitted beam into a parallel beam; the linear beam focusing lens 3 is used to constrain the width of the linear laser; the Powell prism 4 is used to shape the collimated beam into a linear laser along the corresponding direction; the linear beam collimating lens group 5 is used to collimate the linear laser and emit parallel light; the near-end receiving screen 6 and the far-end receiving screen 7 on both sides of the working range are used to observe the intensity distribution of the linear laser within the working range.

[0035] In this embodiment, the surface formula of the biconical lens 2 is:

[0036]

[0037] Among them, k x k is the cone coefficient of the biconical lens 2 in the x direction; yis the cone coefficient of the biconical lens 2 in the y direction; c x is the curvature of the biconical lens 2 in the x direction; c y is the curvature of the biconical lens 2 in the y direction; x, y, z are the coordinate values ​​of a point on the biconical lens 2.

[0038] In the device, the biconical lens 2 collimates the outgoing light beam of the laser diode 1 into a parallel light beam. Figure 3 As shown, the luminous point of the fast axis beam is located at the focus of the dual axis lens, and the fast axis beam is emitted horizontally; similarly, Figure 4 As shown, the light-emitting point of the slow-axis beam is also located at the focus of the biaxial lens, and the slow-axis beam can also be emitted horizontally. This effect can be achieved because the biconical lens 2 is non-axisymmetric and has different surface parameters in the fast axis and slow axis directions, so that the fast axis beam and the slow axis beam can be collimated with high precision at the same time. Therefore, the biconical lens 2 can collimate the elliptical spot emitted by the laser diode 1 with astigmatism into an elliptical spot in which both the fast and slow axes can be emitted in parallel, that is, the biconical lens 2 can collimate the laser beam emitted by the laser diode 1 with astigmatism with high precision, improve the transmission efficiency and the directivity of the beam, and thus achieve the purpose of narrow line width within the working range.

[0039] Therefore, compared with the existing linear laser module, the improved linear laser module eliminates the influence of the astigmatism of the laser diode 1, and collimates and shapes the light beam output by the laser diode 1 into a linear laser with high precision and high quality, thereby avoiding significant energy attenuation and loss, effectively improving the beam quality of the laser line, and thus improving the laser detection accuracy.

[0040] In this embodiment, the wavelength of the laser diode 1 is 400 mm-700 nm, the laser energy distribution is more uniform, and the energy is higher. At the same time, the diameter of the Powell prism 4 is 6 mm-15 mm, the fan angle is 30°-110°, and the long axis of the elliptical beam emitted by the laser diode 1 is perpendicular to the ridge of the Powell prism 4.

[0041] Furthermore, the linear beam focusing lens 3 is a plano-convex aspheric cylindrical lens with positive power, and the focal length of the linear beam focusing lens 3 is 50 mm to 300 mm. The linear beam focusing lens 3 acts on the short axis of the elliptical beam to obtain a narrower line width within the working range.

[0042] In addition, the linear beam collimating lens group 5 includes at least two parallel plano-convex aspheric lenses, and the focal length of the plano-convex aspheric lenses is 10 mm-50 mm. In actual operation, the lens combination of the linear beam collimating lens group 5 in this example can change different focal lengths according to the length of the parallel line to be obtained and the focal depth range of the laser line. At the same time, the linear beam collimating lens group 5 can increase the number of collimating lenses according to actual needs to obtain better parallel light and uniform energy distribution.

[0043] About the use of this linear laser module:

[0044] First, an elliptical laser beam is generated by the laser diode 1 in the linear laser module, and the elliptical laser beam is collimated into a parallel beam through the biconical lens 2; then, the linear beam focusing lens 3 is used to focus only the beam parallel to the ridge of the Powell prism 4, so as to reduce the width of the laser beam in the direction parallel to the ridge.

[0045] Next, the fast axis of the parallel light beam incident perpendicular to the ridge direction of the Powell prism 4 is expanded to form a laser line with a fixed transmission fan angle, while the slow axis width of the parallel light beam parallel to the ridge direction remains unchanged; then, the linear beam collimating lens group 5 acts only on the light beam perpendicular to the ridge direction to generate uniformly emitted parallel light, and finally the intensity distribution of the laser line is obtained on the near-end receiving screen 6 and the far-end receiving screen 7 at both ends of the working range, and finally a linear laser with parallel emission, uniform energy distribution and narrow line width in the entire working range is obtained.

[0046] Therefore, the linear laser module can collimate and focus the laser beams in the fast axis and slow axis directions, independently and without interfering with each other, so as to obtain parallel linear lasers with uniform energy distribution, long focal depth, and line width that meet the requirements of high-precision optical measurement. Compared with ordinary linear lasers, the camera reception efficiency of parallel linear lasers on strongly reflective planes (such as metals, ceramics, etc.) is greatly improved.

[0047] The present invention is described above in conjunction with the best embodiments, but the present invention is not limited to the embodiments disclosed above, but should cover various modifications and equivalent combinations based on the essence of the present invention.

Claims

1. An improved linear laser module, characterized in that: It comprises a laser diode (1), a biconical lens (2), a linear beam focusing lens (3), a Powell prism (4), a linear beam collimating lens group (5), a near-end receiving screen (6), and a far-end receiving screen (7) which are sequentially arranged along the light output axis direction; The surface formula of the biconical lens (2) is: Among them, k x k is the cone coefficient of the biconical lens (2) in the x direction; y is the cone coefficient of the biconical lens (2) in the y direction; c x is the curvature of the biconical lens (2) in the x direction; c y is the curvature of the biconical lens (2) in the y direction; x, y, z are the coordinate values ​​of a point on the biconical lens (2).

2. The improved linear laser module according to claim 1, characterized in that: The Powell prism (4) has a diameter of 6 mm to 15 mm and a fan angle of 30° to 110°.

3. The improved linear laser module according to claim 2, characterized in that: The major axis of the elliptical light beam emitted by the laser diode (1) is perpendicular to the ridge of the Powell prism (4).

4. The improved linear laser module according to claim 1, characterized in that: The linear light beam focusing lens (3) is a plano-convex aspherical cylindrical lens with positive optical power.

5. The improved linear laser module according to claim 4, characterized in that: The focal length of the linear light beam focusing lens (3) is 50 mm-300 mm.

6. The improved linear laser module according to claim 1, characterized in that: The linear beam collimating lens group (5) comprises at least two parallel arranged plano-convex aspheric lenses.

7. The improved linear laser module according to claim 6, characterized in that: The focal length of the plano-convex aspheric lens is 10 mm-50 mm.

8. The improved linear laser module according to claim 1, characterized in that: The wavelength of the laser diode (1) is 400 nm-700 nm.

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