Laser shaping system and laser printer

Abstract

The invention relates to the technical field of light paths, and particularly discloses a laser shaping system and a laser printer, the laser shaping system comprises an LD collimating lens, a rotating mirror, a focusing lens and a focusing surface which are arranged in sequence; the LD collimating lens is used for receiving a first fast-axis laser beam and a first slow-axis laser beam, converting the first fast-axis laser beam into a fast-axis collimated beam, and converting the first slow-axis laser beam into a slow-axis collimated beam; wherein the fast axis collimated light beam and the slow axis laser light beam are parallel light beams; the rotating mirror is used for performing deflection processing on the fast-axis collimated light beam to obtain a second fast-axis laser beam, and performing deflection processing on the slow-axis laser beam to obtain a second slow-axis laser beam; and the focusing lens is used for focusing the second fast axis laser beam and the second slow axis laser beam to the focusing surface. The invention can bear high-power laser, and is low in light path cost and easy to process.

Description

Technical Field

[0001] The invention relates to the field of optical path technology, and in particular to a laser shaping system and a laser printer. Background Art

[0002] Existing laser printers use semiconductor lasers (Laser Diode, referred to as LD) as light sources. The wavelength of the device is infrared laser, about 780nm. The common optical path of existing laser printers is as follows: Figure 2 As shown, specifically: 1) The light beam emitted by the LD passes through the laser collimating lens and becomes a parallel light beam. 2) The parallel laser shines on the side of the multi-faceted prism (the side of the multi-faceted prism is a highly reflective mirror). When the rotating mirror motor rotates, it drives the laser beam to scan in the plane. 3) The parallel laser beam shines on the F-theta mirror and is focused on the plane at the focal point. The F-theta mirror is also required to meet the following conditions: the position L of the laser spot is linearly related to the angle θ of the rotating mirror, that is, when the rotating mirror rotates at a uniform speed, the scanning speed of the laser beam on the focal plane of the F-theta mirror is uniform. When the scanning light beam deflected by the rotating mirror is irradiated to different positions of the focal plane, the incident angle is different, and the optical path is also different, so the light spot difference is large.

[0003] The above laser shaping optical path is suitable for low-power (mW level) infrared LD, and the luminous area of ​​LD is about 1um×1um. In recent years, LD has developed rapidly. With the demand for fiber lasers, infrared LD has reached the hundred-watt level, and the width of the luminous area has increased to tens to 200um. The 2014 Nobel Prize in Physics developed a high-brightness blue light-emitting diode based on GaN. At present, the power of blue light LD can reach more than 7 watts, and the width of the luminous area is about 45um. For high-power, large-light-area LDs, the optical path of existing laser printers is no longer applicable. Therefore, it is urgent to provide a technical solution to solve the above problems. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a laser shaping system and a laser printer.

[0005] In a first aspect, the present invention provides a laser shaping system, the technical solution of which is as follows:

[0006] It includes: an LD collimating lens, a rotating mirror, a focusing lens and a focusing surface which are arranged in sequence;

[0007] The LD collimating lens is used to: receive a first fast-axis laser beam and a first slow-axis laser beam, convert the first fast-axis laser beam into a fast-axis collimated beam, and convert the first slow-axis laser beam into a slow-axis collimated beam; wherein the fast-axis collimated beam and the slow-axis laser beam are both parallel beams;

[0008] The rotating mirror is used to: deflect the fast-axis collimated beam to obtain a second fast-axis laser beam, and deflect the slow-axis laser beam to obtain a second slow-axis laser beam;

[0009] The focusing lens is used to focus the second fast-axis laser beam and the second slow-axis laser beam onto the focusing plane.

[0010] The beneficial effects of a laser shaping system of the present invention are as follows:

[0011] The laser shaping system of the present invention can withstand high-power lasers, has low optical path cost, and is easy to process.

[0012] Based on the above solution, a laser shaping system of the present invention can also be improved as follows.

[0013] In an optional manner, the focusing lens includes: a fast-axis focusing lens and a slow-axis focusing lens;

[0014] The fast axis focusing lens is used to: focus the second fast axis laser beam onto the focusing plane;

[0015] The slow-axis focusing lens is used to focus the second slow-axis laser beam onto the focusing plane.

[0016] In an optional manner, the fast axis focusing lens includes: an F-theta mirror and a fast axis collimating lens;

[0017] The F-theta mirror is used to: focus the parallel beam in the second fast-axis laser beam onto the focusing plane;

[0018] The fast axis collimating lens is used to collimate the light beams with different incident angles in the second fast axis laser light beam and irradiate them vertically to the focusing plane.

[0019] In an optional manner, it further includes: a semiconductor laser; the semiconductor laser is used to: generate and emit the first fast-axis laser beam and the first slow-axis laser beam.

[0020] In an optional manner, it further includes: a slow axis beam expansion group; the slow axis beam expansion group is arranged between the LD collimating lens and the rotating mirror;

[0021] The slow axis beam expansion group is used to: perform beam expansion processing on the slow axis laser beam to obtain an expanded slow axis laser beam, and use the expanded slow axis laser beam as the slow axis laser beam.

[0022] In an optional manner, the LD collimating lens is an aspherical glass lens.

[0023] In an optional manner, the slow-axis beam expansion group includes at least two cylindrical lens groups.

[0024] In an optional manner, the F-theta mirror is composed of at least two cylindrical mirrors.

[0025] In an optional manner, the fast axis collimating lens is a cylindrical lens.

[0026] In a second aspect, the present invention provides a laser printer, which includes a laser shaping system according to the present invention.

[0027] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are only used to illustrate the embodiments and are not to be considered as limiting the present invention. In addition, the same reference symbols are used to represent the same components throughout the accompanying drawings. In the accompanying drawings:

[0029] Figure 1 A schematic structural diagram of an embodiment of a laser shaping system of the present invention;

[0030] Figure 2 It is a structural schematic diagram of the existing laser printing optical path;

[0031] Figure 3 It is the principle schematic diagram of LD collimating lens;

[0032] Figure 4 is a schematic diagram of the structure of a slow-axis focusing lens;

[0033] Figure 5 This is the principle diagram of the slow axis beam expansion group;

[0034] Figure 6 Schematic diagram of the comparison of laser spots. DETAILED DESCRIPTION

[0035] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0036] Figure 1 FIG. 2 shows a schematic diagram of a structure of an embodiment of a laser shaping system provided by the present invention. Figure 1 As shown, the laser shaping system includes: an LD collimating lens 2, a rotating mirror 4, a focusing lens and a focusing surface 8 which are arranged in sequence.

[0037] The LD collimating lens 2 is used to receive a first fast-axis laser beam and a first slow-axis laser beam, convert the first fast-axis laser beam into a fast-axis collimated beam, and convert the first slow-axis laser beam into a slow-axis collimated beam.

[0038] Wherein, the fast axis collimated beam and the slow axis laser beam are parallel beams. The first fast axis laser beam and the first slow axis laser beam are laser beams emitted by the target light source. The first fast axis laser beam is parallel to the plane where the laser shaping system is located, and the first slow axis laser beam is perpendicular to the plane where the laser shaping system is located. The LD collimating lens 2 is an aspherical glass lens. Figure 3 As shown, the laser beams (the first fast-axis laser beam and the first slow-axis laser beam) emitted by the target light source become parallel beams (the fast-axis collimated beam and the slow-axis collimated beam) after passing through the LD collimating lens 2.

[0039] The rotating mirror 4 is used to deflect the fast-axis collimated beam to obtain a second fast-axis laser beam, and to deflect the slow-axis laser beam to obtain a second slow-axis laser beam.

[0040] The side of the rotating mirror 4 receives the fast axis collimated beam and the slow axis laser beam. The side of the rotating mirror 4 is coated with a high reflective film layer for laser. The side of the rotating mirror 4 is a plane, and the flatness requirement is higher than 0.15um.

[0041] The focusing lens is used to focus the second fast-axis laser beam and the second slow-axis laser beam onto the focusing plane 8 .

[0042] The focusing lens includes a fast axis focusing lens and a slow axis focusing lens 7. Specifically:

[0043] The fast-axis focusing lens is used to focus the second fast-axis laser beam onto the focusing plane 8 .

[0044] The fast-axis focusing lens includes: an F-theta mirror 5 and a fast-axis collimating lens 6. The laser beam (the second fast-axis laser beam and the second slow-axis laser beam) passing through the rotating mirror 4 is sequentially irradiated to the F-theta mirror 5 and the fast-axis collimating lens 6. The F-theta mirror 5 is composed of at least two cylindrical mirrors, and the fast-axis collimating lens 6 is a cylindrical mirror. The F-theta mirror 5 and the fast-axis collimating lens 6 have a curved curvature in the plane where the laser shaping system is located; the F-theta mirror 5 and the fast-axis collimating lens 6 have no curvature in the direction perpendicular to the plane where the laser shaping system is located.

[0045] The F-theta mirror 5 is used to focus the parallel light beam in the second fast-axis laser beam onto the focusing plane 8 .

[0046] Specifically, the F-theta mirror 5 focuses the parallel light beam in the fast axis direction (the parallel light beam in the second fast axis laser beam) onto the focusing plane 8, and at the same time, the position L of the laser spot is linearly related to the angle θ of the rotating mirror 4, that is, when the rotating mirror 4 rotates at a uniform speed, the scanning speed of the laser beam on the plane of the F-theta mirror 5 is uniform.

[0047] The fast-axis collimating lens 6 is used to collimate the light beams with different incident angles in the second fast-axis laser beam and irradiate them vertically onto the focusing plane 8 .

[0048] Specifically, the fast-axis collimating lens 6 collimates the light beams with different incident angles in the fast-axis direction (light beams with different incident angles in the second fast-axis laser beam) and irradiates them vertically onto the focusing plane 8 to form a telecentric optical path.

[0049] It should be noted that, unlike the existing laser shaping optical path, the laser shaping system of this embodiment constitutes a telecentric optical path, and the light with different incident angles (corresponding to the light beams at different positions on the focusing plane 8) has the same incident angle and close optical path after being deflected by the rotating mirror 4 on the focusing plane 8, so the light spot magnification is the same. The fast axis focusing lens has no focusing effect on the slow axis.

[0050] The slow-axis focusing lens 7 is used to focus the second slow-axis laser beam onto the focusing plane 8 .

[0051] The parallel light beam in the slow axis direction (the second slow axis laser beam) is focused onto the focusing plane 8 after passing through the slow axis focusing lens 7. Figure 4 As shown, the slow axis focusing lens 7 is a cylindrical lens, and the slow axis focusing lens 7 has no curvature on the plane where the laser shaping system is located. The slow axis focusing lens 7 has a curved surface with a certain curvature radius in a direction perpendicular to the plane where the laser shaping system is located.

[0052] In an optional manner, it further includes: a semiconductor laser 1; the semiconductor laser 1 is used to: generate and emit the first fast-axis laser beam and the first slow-axis laser beam.

[0053] Among them, the light-emitting area of ​​the semiconductor laser 1 is divided into a fast axis (used to generate a first fast axis laser beam) and a slow axis (used to generate a first slow axis laser beam). The broadband of the light-emitting area in the fast axis direction is generally about 1um, and the divergence angle in the fast axis direction is relatively large. The width of the light-emitting area in the slow axis direction of the high-power LD is relatively large, ranging from 20um to hundreds of microns, and the divergence angle in the slow axis direction is relatively small, generally less than half of the divergence angle of the fast axis.

[0054] In an optional manner, it further includes: a slow axis beam expansion group 3 ; the slow axis beam expansion group 3 is arranged between the LD collimating lens 2 and the rotating mirror 4 .

[0055] The slow axis beam expansion group 3 is used to expand the slow axis laser beam to obtain an expanded slow axis laser beam, and use the expanded slow axis laser beam as the slow axis laser beam.

[0056] Among them, Figure 5 As shown, the slow axis beam expansion group 3 includes at least two cylindrical lens groups. Since the light emitting widths of the fast and slow axes differ greatly and the divergence angle of the slow axis is small, a group of slow axis beam expansion groups 3 is selectively added according to the requirements of the final focused light spot.

[0057] In this embodiment, it should be noted that, assuming that the focal length of the LD collimating lens 2 is F1, the combined focal length of the fast-axis focusing lens composed of the F-theta mirror 5 and the fast-axis collimating lens 6 is F2. Then the magnification of the light spot in the fast axis direction is M1=F2 / F1. Assuming that the LD collimating lens 2 and the slow-axis beam expander group 3 together form a slow-axis collimating lens, whose combined lens focal length is F3, and the focal length of the slow-axis focusing lens 7 is F4, then the magnification of the light spot in the slow axis direction is M2=F4 / F3. By adjusting the combined focal length of different lenses, the above two magnifications can be changed to achieve light spots with different aspect ratios. For example, Figure 6 The left side shows the original light spot produced by semiconductor laser 1. Figure 6 The right side shows the light spot after being shaped by the laser shaping system in this embodiment, and the two have different magnification ratios in the length and width directions.

[0058] The technical solution of this embodiment can withstand high-power lasers, has low optical path costs, and is easy to process.

[0059] The laser printer provided in the embodiment of the present invention includes a laser shaping system as in the present embodiment. For details, reference may be made to the parameters and structures in the embodiment of a laser shaping system described above, which will not be described in detail here.

[0060] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. Similarly, in order to simplify the present invention and help understand one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, the various features of the embodiments of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. Wherein, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, wherein each claim itself is a separate embodiment of the present invention.

[0061] It should be noted that the above embodiments illustrate the present invention rather than limit it, and that those skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets shall not be construed as a limitation on the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention may be implemented by means of hardware comprising a number of different elements and by means of a suitably programmed computer. In a unit claim enumerating a number of devices, several of these devices may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words may be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be understood as limitations on the order of execution.

Claims

1. A laser shaping system, characterized in that: include: An LD collimating lens, a rotating mirror, a focusing lens and a focusing surface are arranged in sequence; The LD collimating lens is used to: receive a first fast-axis laser beam and a first slow-axis laser beam, convert the first fast-axis laser beam into a fast-axis collimated beam, and convert the first slow-axis laser beam into a slow-axis collimated beam; wherein the fast-axis collimated beam and the slow-axis laser beam are both parallel beams; The rotating mirror is used to: deflect the fast-axis collimated beam to obtain a second fast-axis laser beam, and deflect the slow-axis laser beam to obtain a second slow-axis laser beam; The focusing lens is used to focus the second fast-axis laser beam and the second slow-axis laser beam onto the focusing plane.

2. The laser shaping system according to claim 1, characterized in that: The focusing lens comprises: a fast axis focusing lens and a slow axis focusing lens; The fast axis focusing lens is used to: focus the second fast axis laser beam onto the focusing plane; The slow-axis focusing lens is used to focus the second slow-axis laser beam onto the focusing plane.

3. The laser shaping system according to claim 2, characterized in that: The fast axis focusing lens comprises: an F-theta mirror and a fast axis collimating lens; The F-theta mirror is used to: focus the parallel beam in the second fast-axis laser beam onto the focusing plane; The fast axis collimating lens is used to collimate the light beams with different incident angles in the second fast axis laser light beam and irradiate them vertically to the focusing plane.

4. The laser shaping system according to claim 1, characterized in that: Also includes: Semiconductor laser; the semiconductor laser is used to: generate and emit the first fast-axis laser beam and the first slow-axis laser beam.

5. The laser shaping system according to claim 1, characterized in that: Also includes: A slow axis beam expansion group; the slow axis beam expansion group is arranged between the LD collimating lens and the rotating mirror; The slow axis beam expansion group is used to: perform beam expansion processing on the slow axis laser beam to obtain an expanded slow axis laser beam, and use the expanded slow axis laser beam as the slow axis laser beam.

6. The laser shaping system according to any one of claims 1 to 5, characterized in that: The LD collimating lens is an aspherical glass lens.

7. The laser shaping system according to claim 5, characterized in that: The slow axis beam expansion group includes at least two cylindrical lens groups.

8. The laser shaping system according to claim 3, characterized in that: The F-theta mirror is composed of at least two cylindrical mirrors.

9. The laser shaping system according to claim 3, characterized in that: The fast axis collimating lens is a cylindrical lens.

10. A laser printer, characterized in that: The laser shaping system comprises the laser shaping system as claimed in any one of claims 1 to 9.

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