Leveling laser and optical projection lens

Abstract

A leveling laser (10) for generating a laser projection line (20) on a surface (22) is proposed, the leveling laser (10) comprising an optical projection lens (34) with a three-dimensional lens surface (46), wherein the projection lens (34) can be described in a three-dimensional coordinate system (32) with three axes x, y, z arranged perpendicular to one another, wherein the z axis coincides with the optical axis of the projection lens (34). According to the invention, the lens surface (46) of the projection lens (34) has a shape with a monotonically increasing surface inclination (44) in the direction of the axis x. The invention also relates to a corresponding projection lens (34).

Description

Technical Field

[0001] The invention relates to a leveling laser comprising an optical projection lens for generating a laser projection line on a surface, and to a corresponding optical projection lens. Background Art

[0002] The general design of a leveling laser, in particular a self-aligning leveling laser (so-called pendulum laser), is known from DE 10 2007 039 343 A1.

[0003] Optical lenses based on free-form surfaces are known from the prior art, for example from the technical field of laser rangefinders. EP 2379983 B1 discloses, for example, a free-form lens for compensating for optical power losses that occur when measuring small distances from a laser rangefinder to a target. The problem with such near-field measurements is that the parallax deviation between the emitted laser beam and the received, i.e. reflected, laser beam can have a relatively strong influence on the measurement result. The power loss thus has the effect, in particular, that the laser beam imaged on the detector of the laser rangefinder no longer completely hits the active surface of the detector due to the parallax deviation between the emission path and the reception path. Summary of the invention

[0004] In a first aspect, the invention relates to a leveling laser (also called a leveling device) for generating a laser projection line on a surface. The leveling laser is used here to generate optical markings in the form of laser projection lines within the scope of leveling tasks, alignment tasks, measuring tasks and / or marking tasks that occur, in particular, in the field of handicrafts, for example, during interior decoration of buildings, during construction work, when applying markings on walls or the like. The exact design of the laser projection line generated by means of the leveling laser can also vary depending on the field of use and the task. The laser projection line can therefore also include a plurality of marking points and / or a plurality of marking lines, including also interrupted marking lines. In addition, the leveling laser can be configured to realize the laser projection line in a time-varying manner, in particular, for example, flickeringly. The leveling laser allows, in principle, the generation of laser markings, in particular projection onto an object that is a reference object that is independent of the orientation of a floor, ceiling, wall or other object, such as a vertical wall of a cabinet.

[0005] The leveling laser typically has a housing with at least one opening, in particular a window, through which the laser projection line is emitted onto the surface on which the laser projection line is to be generated. The leveling laser is dimensioned so that it can be transported by hand, in particular with one hand, without the aid of a transport machine. The mass of the leveling laser is less than 5 kg, in particular less than 2 kg and very particularly less than 1 kg. The dimension of the leveling laser in a first direction (in particular the direction of the axis x, see below) is less than 15 cm, in particular less than 10 cm, very particularly less than 5 cm. The dimension of the leveling laser in a second direction (in particular the direction of the axis z and / or y, see below) is less than 25 cm, in particular less than 15 cm, very particularly less than 10 cm.

[0006] The leveling laser is provided for leveling the emitted laser projection line, for example, horizontally, vertically or according to other leveling angles. The leveling angle can be selected by the user in particular. Leveling can be performed, for example, using a swing device arranged in the housing of the leveling laser, by means of which the laser projection line can be freely self-aligned, in particular, can be emitted in a swinging or oscillating manner, independently of the orientation of the housing at the plumb line. The swing device carries and level all optical components of the leveling laser, that is, at least one laser unit and projection lens for generating laser radiation. The housing can alternatively realize manual alignment of the laser projection line. In this case, the optical components, that is, at least the laser unit and projection lens for generating laser radiation are firmly arranged in the housing of the leveling laser. It is also conceivable that a leveling sensor, in particular an inertial sensor, a magnetic field sensor, an acceleration sensor, a gravity sensor or the like, and / or a level gauge are provided in the housing, and when using them, the laser projection line can be brought into the desired leveled state manually (by the user) and / or automatically (for example, driven by a motor). The leveling laser can in particular comprise an output device, in particular an optical, acoustic or tactile output device, by means of which the leveling state can be output to the user. The user can thus recognize from the level and / or the output signal when or under what conditions ('turned by 5° more') the leveled state of the laser projection line exists.

[0007] The leveling laser comprises at least one laser unit and an optical projection lens with a three-dimensional lens surface as optical components, wherein the projection lens can be described in a three-dimensional coordinate system with three axes x, y, z arranged perpendicular to each other, and wherein the axis z coincides with the optical axis of the projection lens. In one embodiment of the leveling laser, the laser unit and the projection lens are the only optical components in the emission path (also called projection path) of the leveling laser. The laser unit has at least one laser light source, such as a semiconductor laser or a laser diode. In one embodiment, the laser radiation is provided in the spectral wavelength range visible to the human eye, that is to say in particular between 380 nm and 780 nm, for example, a red laser light set to 635 nm. In addition, the laser unit can include optical elements that form and / or guide the beam and / or influence the properties of the laser radiation, such as, for example, lenses, such as collimators, collimating lenses, filters, diffraction elements, mirrors, reflectors, optically transparent glass sheets or the like.

[0008] The projection lens is arranged in the emission path of the leveling laser. The projection lens is used to refract and fan out the laser beam into a laser fan (laser plane) extending in a plane spanned by axes x and z. The intersection of this laser plane with the surface generates a laser projection line visible to the human eye. In one embodiment of the leveling laser, the projection lens has a mirror-symmetrical, particularly cylindrical shape in the direction of the axis y. In this way, it can be achieved that the projection lens does not exert a refractive power in the direction of the axis y and therefore radiates the entire radiation power of the laser beam into the laser fan in a particularly effective fan shape. The laser projection line can therefore be particularly narrow (laterally limited) in the direction of the axis y. In one embodiment of the leveling laser, the projection lens can be irradiated in the direction of the optical axis by means of a collimated laser beam or irradiated accordingly in the application state or operating state of the laser unit. The collimated laser beam can be generated in particular when using a collimator or a collimating lens, which is located behind the laser unit and in particular in front of the projection lens in the optical emission path. In one embodiment, the projection lens and the collimating lens are integrated into a single lens component. In this case, it can be provided, in particular in one embodiment of the leveling laser, that the laser unit and the lens component are the only optical components in the emission path of the leveling laser. The collimating lens and the laser unit can alternatively be integrated into a separate laser unit component. In this case, it can be provided, in particular, in one embodiment of the leveling laser, that the laser unit component and the projection lens are the only optical components in the emission path of the leveling laser. In particular, in this way, compact components that are particularly comprehensive in their functions can be provided, and the leveling laser can be designed to be particularly small. In addition, the installation and alignment of the optical components are significantly simplified in the manufacturing method of the leveling laser. In one embodiment of the leveling laser, the projection lens is made of plastic. The plastic is optically transparent at least for the wavelength of the laser light used. The projection lens can advantageously be manufactured from plastic, for example by an injection molding method, in a particularly cost-effective and at the same time precise manner.

[0009] In one embodiment of the leveling laser, the leveling laser is configured to be arranged directly on a surface. The arrangement on the surface can be carried out with the aid of retaining means known to a person skilled in the art, such as adhesive tape, screws or the like. The housing of the leveling laser can in particular include corresponding devices, such as a reusable adhesive pad arranged on the rear side of the housing, as is known from US 9,909,035 B. In one embodiment, the leveling laser is configured to project a laser projection line onto a surface on which the leveling laser is arranged in the applied state or to generate a laser projection line on a surface on which the leveling laser is arranged in the applied state. In one embodiment of the leveling laser, the laser projection line can be projected onto a surface, wherein the laser projection line has an orientation parallel to the optical axis of the projection lens, in particular also parallel to the optical axis of the laser radiation incident on the projection lens, and is spaced from this optical axis by a deviation in the direction of the axis x. The surface is in a plane bounded by the axes y and z, wherein the surface is spaced from the optical axis of the projection lens by a deviation along the axis x. In this way, a leveling laser can be provided which is particularly simple and intuitive to operate. The required space requirement is particularly low, since the leveling laser does not need to be at a distance from the surface, as is the case, for example, with the tumbling lasers known from the prior art.

[0010] In order to generate a laser projection line that is illuminated as evenly as possible on a surface, in particular a surface on which the leveling laser is arranged in the applied state, it is proposed that the lens surface has a shape with a monotonically increasing surface inclination along the axis x at least in the section of the projection lens that can be used to generate the laser projection line. The lens surface is especially implemented as a free-form surface. The lens surface can be described in the direction of the axis z by a function z = f(x), where the derivative is a monotonically increasing function. According to the invention, it is possible to generate, in particular project, a laser projection line which is illuminated as evenly as possible on a surface, starting from a particularly collimated laser beam, wherein the leveling laser is simultaneously arranged on the surface. The projection lens allows providing an intensity distribution which is asymmetrical with respect to the optical axis of the projection lens.

[0011] The surface tilt is the angle of the lens surface relative to the axis x.

[0012] "A section of the projection lens that can be used to generate a laser projection line" means, in particular, that the section of the projection lens that is used to generate the laser projection line and is illuminated by the incident laser radiation has the described shape. Deviations from the shape according to the invention are conceivable in this section of the projection lens within the scope of manufacturing tolerances. Furthermore, significant deviations from the shape according to the invention are conceivable in this section of the projection lens, which sections are either not illuminated by laser radiation or whose contribution to the generation of the laser projection line is negligible (for example, because these parts of the laser fan are blocked by the housing).

[0013] In one embodiment of the leveling laser, a maximum surface inclination is provided on the side of the projection lens facing the surface when viewed in the direction of the axis x. In this case, the maximum surface inclination can depend on the minimum distance between the laser projection line and the projection lens. The minimum distance in particular characterizes the starting point of the laser projection line when viewed from the leveling laser in the direction of the axis z. In particular, the maximum surface inclination is selected so that the minimum distance is less than 100 mm, in particular less than 50 mm, and very particularly less than 25 mm. In one embodiment, the minimum distance is 10 mm. Therefore, a minimum surface inclination is also provided on the side of the projection lens facing away from the surface when viewed in the direction of the axis x. In this case, the minimum surface inclination can depend on the maximum distance between the laser projection line and the projection lens. The maximum distance here characterizes the end point of the laser projection line when viewed from the leveling laser in the direction of the axis z. In particular, the minimum surface inclination is selected so that the maximum distance is greater than 750 mm, in particular greater than 1500 mm, and very particularly greater than 2000 mm.

[0014] Thus, according to the invention, a laser projection line can be generated on a surface, which is at the same time the placement or arrangement surface (or basis) for the arranged leveling laser. Compared to devices known from the prior art, in which the laser projection line is generated by means of a strip-shaped incident laser beam emitted by a laser unit on the surface, the present leveling laser allows a significantly simpler construction (without mirrors or the like) while also providing extremely uniform illumination of the laser projection line over its entire length.

[0015] In a further aspect of the invention, an optical projection lens of the above-described leveling laser with a three-dimensional lens surface is proposed, wherein the projection lens can be described in a three-dimensional coordinate system with three mutually perpendicular axes x, y, z, and wherein the z axis coincides with the optical axis of the projection lens. According to the invention, the lens surface of the optical projection lens has at least partially a shape with a monotonically increasing surface inclination along the x axis.

[0016] “Provision” and “provided” are to be understood in particular as specifically “programmed”, “designed” and / or “equipped”. An object being “provided” for a specific function is to be understood in particular as meaning that the object performs and / or carries out this specific function in at least one application state and / or operating state or is designed to perform the function. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The invention is explained in more detail in the following description with the aid of the embodiments shown in the drawings. The drawings, the description and the claims contain a large number of combined features. A person skilled in the art will also appropriately view the features individually and combine them into other reasonable combinations. The same reference numerals in the drawings mark the same elements.

[0018] Figure 1 is a stereogram of a design of a leveling laser according to the present invention;

[0019] Figure 2 a is Figure 1 A schematic side view of a design of a leveling laser according to the present invention;

[0020] Figure 2 b is a schematic side view of an optical component including a projection lens according to the present invention;

[0021] Figure 3 The enlarged view shows Figure 2 b Schematic side view of the optical components. DETAILED DESCRIPTION

[0022] Figure 1 The illustration shows an embodiment of a leveling laser 10 according to the invention in a three-dimensional side view. The leveling laser 10 is used to generate a laser projection line 20 on a surface 22. The leveling laser 10 has a flat, essentially annular housing 12 with a diameter of approximately 10 cm and a maximum height of approximately 5 cm. The leveling laser 10 has a mass of approximately 300 grams. The housing 12 is preferably essentially made of a polymer material or a composite material, such as a fiber-reinforced material (for example a fiber-reinforced thermosetting plastic or thermoplastic). The housing 12 surrounds the mechanical, optical and electronic components of the leveling laser 10 and protects them from mechanical damage and reduces the risk of contamination. In order to reduce the harmful effects of impacts on the leveling laser 10 and to make it more comfortable for the user to operate, the housing 12 is partially covered with a soft grip part 14. On the front side (not shown in detail here), an opening, in particular an outlet, is provided in the housing 12. Optical signals, in particular from a laser unit 16 arranged in the housing 12 (see in particular Figure 3) can exit the housing 12 through an outlet for generating at least one laser projection line 20 on a surface 22 of an object. The outlet is provided with a window element (not shown in detail) which is transparent, but at least translucent, for the laser radiation 18, so that the interior of the leveling laser 10 is protected from damage and environmental influences, for example from the ingress of moisture and dust.

[0023] The housing 12 has an upper housing shell 26 and a lower housing shell 28 (see Figure 2 a), wherein the upper housing shell 26 is mounted rotatably relative to the lower housing shell 28. This makes it possible for the user of the leveling laser 10 to rotate the direction of the emitted laser radiation 18 relative to the leveling laser 10, in particular relative to the center of the leveling laser 10.

[0024] A switch 24 is located on an upper housing shell 26 of the housing 12 , the actuation of which activates / deactivates the energy supply of the electronics arranged in the housing 12 , in particular of the laser unit 16 and of the sensor device.

[0025] The leveling laser 10 is arranged with its underside (that is to say with the lower housing shell 28 facing forward) directly on or at the surface 22. In the exemplary embodiment shown, the leveling laser 10 is reversibly arranged on the surface 22 using a reusable adhesive pad applied to the rear side of the housing. The leveling laser 10 is designed to project the laser projection line 20 directly onto the surface 22 on which or at which the leveling laser is arranged. For the following description, a three-dimensional coordinate system 32 is defined, which includes three axes x, y, z arranged perpendicular to one another. The axis z coincides with the optical axis of the projection lens 34 (see in particular ). Figure 2 a, 2b), the surface 22 is substantially parallel to the plane spanned by the axes y and z and is spaced apart by a distance 36 ( ) (See also Figure 2 a, 2b).

[0026] exist Figure 1Not shown in greater detail are the battery compartments arranged laterally on the housing 12 for accommodating the batteries for powering the leveling laser 10 and the further electronic components for leveling the leveling laser 10. The further components include at least one tilt sensor, by means of which the tilt of the leveling laser 10, in particular the emitted laser radiation 18, can be determined, for example, relative to a plumb line and / or relative to a horizontal line or the like. The tilt sensor is connected at least to an output device 30, which is implemented here as an illuminating LED strip, for signaling purposes, wherein in the leveled state of the leveling laser 10 a green light signal is emitted to indicate the leveled state to the user, while in the unleveled state a red light signal is emitted to indicate the unleveled state to the user. In order to go from the unleveled state to the leveled state, the user has to rotate the upper housing shell 26 only relative to the lower housing shell 28 connected to the surface 22 until the emitted laser radiation 18 is leveled and the output device 30 emits a green light signal. It should be noted that the leveling laser 10 is particularly suitable for use on vertical walls, so that a horizontally leveled laser projection line 20 and / or a vertically leveled laser projection line 20 can be set by rotating the upper housing shell 26. It is also conceivable that the leveling angle (e.g. "45°") can be predefined, for example, by an external device such as a smartphone or the like that can be connected to the leveling laser 10 for signaling purposes.

[0027] Figure 2 a shows the previously described leveling laser 10 in a schematic side view. Figure 2 b shows the optical components of the leveling laser 10 in a schematic side view. The leveling laser 10 comprises at least one laser unit 16 and an optical projection lens 34 as optical components. The laser unit 16 is implemented by a laser diode here. The projection lens 34 has a three-dimensional lens surface, wherein the axis z of the coordinate system 32 coincides with the optical axis of the projection lens 34. In addition, the optical components (the exit window is not considered an important optical component because it hardly affects the properties of the laser radiation 18) include a collimator lens 38. The optical components together form the emission path of the leveling laser 10. The projection lens 34 is used for the refraction and fanning of the laser beam into a laser fan 18a (laser plane) extending in a plane spanned by the axes x and z. The intersection of this laser fan 18a with the surface 22 generates a laser projection line 20 visible to the human eye. According to the present invention, the optical components are designed in such a way that a laser projection line 20 that is illuminated as evenly as possible on the surface 22 is achieved. The laser projection line 20 extends between a starting point 50 and an end point 54 ( Figure 2 a), between the starting point and the end point, the illumination of the laser projection line 20 is particularly uniform.

[0028] As in Figure 2 b and Figure 3 As shown in the enlarged view in FIG. 1 , the laser radiation 18 is emitted by the laser unit 16 and collimated into a collimated laser radiation 18 b by means of a collimating lens 38. The projection lens 34 is illuminated by means of this collimated laser radiation 18 b. Since only the part of the laser fan 18 a extending in the direction of the surface 22 is needed, the projection lens 34 is partially blackened (becomes opaque), so that the projection lens is divided into a section 40 that can be used to generate the laser projection line 20 and a section 42 that cannot be used to generate the laser projection line 20. This division can of course also be caused separately, for example, when a diaphragm is used. The projection lens 34 is made of plastic. The projection lens 34 has a mirror-symmetrical shape in the direction of the axis y, so that the refractive power cannot be exerted in the direction of the axis y and the fan-shaped expansion of the collimated laser radiation 18 b is basically carried out in the plane of the laser fan 18 a. The laser projection line 20 can therefore be particularly narrow. It is also conceivable that the projection lens 34 is designed in the direction of the axis y so that the refractive power acting in the direction of the axis y is exerted. This makes it possible to generate particularly fine laser projection lines 20 .

[0029] The lens surface of the projection lens 34 has, at least in the section 40 of the projection lens 34 which can be used to generate the laser projection lens 20, a shape with a monotonically increasing surface inclination 44 along the axis x, see in particular Figure 3 The surface inclination angle 44 is the angle of the lens surface 46 (facing the laser unit 16) relative to the axis x. The lens surface 46 is in particular realized as a free-form surface and can be described in the direction of the axis z by the function z=f(x), wherein the derivative is a monotonically increasing function. The maximum surface inclination angle 44 is as Figure 2 b and Figure 3 As can be seen in FIG. 1 , it is arranged on the side of the projection lens 34 facing the surface 22 and is selected so that the minimum distance 48 (see FIG. 4 ) between the starting point 50 of the laser projection line 20 and the leveling laser 10 is Figure 2 a) is less than 25 mm. Furthermore, the smallest surface inclination angle 44 on the side of the projection lens 34 facing away from the surface 22 is selected so that the largest spacing 52 (see Figure 2 a), that is to say up to the end 54 of the laser projection line 20, greater than 1500 mm, wherein at this maximum distance the illumination of the laser projection line 20 is still substantially uniform.

Claims

1. A leveling laser (10) for generating a laser projection line (20) on a surface (22), comprising an optical projection lens (34) with a flat, substantially annular housing (12) and a three-dimensional lens surface (46), wherein: The projection lens (34) can be described in a three-dimensional coordinate system (32) having three axes x, y, z arranged perpendicular to each other, wherein the z axis coincides with the optical axis of the projection lens (34) and the surface (22) is substantially parallel to a plane spanned by the axes y and z, the projection lens (34) is used for refraction and fanning of a laser beam into a laser fan (18a) extending in a plane spanned by the axes x and z, and is characterized in that the projection lens (34) is divided into a section (40) that can be used to generate a laser projection line (20) and a section (42) that cannot be used to generate a laser projection line (20), and the lens surface (46) is at least in the section (42) of the projection lens (34) that can be used to generate a laser projection line (20). 0) has a shape with a surface inclination (44) that increases monotonically along the direction of the axis x, the surface inclination (44) being the angle of the lens surface (46) facing the laser unit (16) relative to the axis x, the maximum surface inclination (44) being arranged on the side of the projection lens (34) facing the surface (22), the maximum surface inclination (44) being dependent on the minimum distance (48) between the laser projection line (20) and the projection lens (34), the minimum surface inclination (44) being arranged on the side of the projection lens (34) facing away from the surface (22), the minimum surface inclination (44) being dependent on the maximum distance (52) between the laser projection line (20) and the projection lens (34).

2. The leveling laser (10) according to claim 1, characterized in that The projection lens (34) has a mirror-symmetrical cylindrical shape along the direction of the axis y.

3. The leveling laser (10) according to claim 1 or 2, characterized in that The projection lens (34) can be illuminated by means of a collimated laser beam (18b) in the direction of an optical axis of the projection lens (34).

4. The leveling laser (10) according to claim 1 or 2, characterized in that The projection lens (34) is made of plastic.

5. The leveling laser (10) according to claim 1 or 2, characterized in that The projection lens (34) and the collimating lens (38) are integrated into a single lens component.

6. An optical projection lens (34) for a leveling laser (10) according to any one of the preceding claims.

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