Optical system
By adjusting and shaping the polarization angle and intensity of the laser beam through an optical system, a flat-top beam with uniform energy is generated, which solves the problem of uneven stress in the transfer and removal process of LED chips caused by the uneven energy of the Gaussian beam, and improves the process yield.
Patent Information
- Application Number
- CN202420863217.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-24
- Publication Date
- 2025-01-07
- Estimated Expiration
- 2034-04-24
AI Technical Summary
In laser processing, the uneven energy distribution of the Gaussian beam leads to uneven stress during the transfer and removal of LED chips, resulting in misalignment, flipping, chip breakage, and uneven surface morphology after solder trimming, thus affecting the process yield.
An optical system is used to adjust and shape the polarization angle, intensity, and cross-sectional size of the laser beam through an incident component, a first shaping component, a second shaping component, and a beam combining component, generating a flat-top beam with uniform energy for the transfer and removal of LED chips.
This technology achieves uniform energy distribution of light spots during the transfer and removal of LED chips, avoids uneven stress, and improves process yield.
Smart Images
Figure CN222319215U_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the field of laser processing technology, and more specifically, relates to an optical system. Background Art
[0002] In laser processing, the energy distribution of ordinary Gaussian beams attenuates from the center to the edge. When transferring and removing micro-sized LED chips, the LED chips will absorb uneven heat from laser radiation, resulting in uneven stress on their surfaces, which will cause the LED chips to shift, flip, and break during the transfer process, and chip residues during the removal process. When trimming the solder after the display backplane is welded once, the solder absorbs uneven heat from laser radiation, resulting in inconsistent melting and sublimation at the center and edges, resulting in poor surface flatness of the trimmed solder, making it unsuitable for secondary welding, and reducing the yield of the process. Utility Model Content
[0003] The embodiment of the present application provides an optical system that can generate a light spot with uniform energy distribution, is suitable for the transfer and removal of LED chips, avoids uneven stress, and is conducive to improving the yield of the process.
[0004] The technical solution adopted in the embodiment of the present application is: to provide an optical system, comprising:
[0005] An incident component, comprising a first half-wave plate and a first polarization beam splitter prism sequentially arranged on the optical path of the laser beam, wherein the first half-wave plate is used to adjust the polarization angle of the incident laser beam, and the first polarization beam splitter prism is used to split the laser beam after the polarization angle is adjusted to generate a first polarization beam and a second polarization beam with different optical paths;
[0006] A first shaping component includes a light intensity regulator and a beam expander which are sequentially arranged in the light path direction of the first polarized light beam, wherein the light intensity regulator is used to adjust the light intensity of the first polarized light beam, and the beam expander is used to adjust the cross-sectional size of the first polarized light beam transmitted through the light intensity regulator to generate a third light beam with a solid circular cross-section;
[0007] A second shaping component, used for shaping the incident second polarized light beam to generate a fourth light beam with a ring-shaped cross section; and
[0008] The beam combining component comprises a beam combining element and a focusing lens, wherein the beam combining element is used to coaxially combine the third light beam and the fourth light beam to generate a flat-top beam, and the focusing lens is used to focus the flat-top beam to form a processing beam.
[0009] Furthermore, the first polarized light beam is P light, and the second polarized light beam is S light.
[0010] Furthermore, a reflection surface of the first polarization beam splitter prism forms an angle of 45° with the optical axis of the laser beam, and a reflection surface of the first polarization beam splitter prism forms an angle of 45° with the optical axis of the second polarized light beam.
[0011] Furthermore, a surface of the first half-wave plate is perpendicular to the optical axis of the laser beam.
[0012] Furthermore, the light intensity regulator includes a second half-wave plate and a second polarization beam splitter prism, and the second half-wave plate, the second polarization beam splitter prism and the beam expander are arranged in sequence along the optical path direction of the first polarized light beam, the surface of the second half-wave plate is perpendicular to the optical axis of the first polarized light beam, and the transmission surface of the second polarization beam splitter prism forms an angle of 45° with the optical axis of the first polarized light beam.
[0013] Furthermore, the beam expander is coaxial with the first polarized light beam.
[0014] Furthermore, the second shaping component includes a first conical lens and a second conical lens arranged in sequence along the optical path of the second polarized light beam, the first conical lens and the second conical lens are symmetrically installed and the conical surfaces are close to each other, and the distance between the first conical lens and the second conical lens can be adjusted within a set range.
[0015] Furthermore, the beam combining assembly further comprises a galvanometer, the focusing lens focuses the processing light beam onto the lens center of the galvanometer, and the galvanometer is used to reflect the processing light beam onto a processing plane.
[0016] Furthermore, the beam combining assembly further comprises an adjustable slit module located between the beam combining element and the focusing lens, wherein the slit module is used to intercept the flat-top beam so that the cross-section of the flat-top beam incident on the focusing lens is rectangular.
[0017] Furthermore, it also includes a first reflector and a second reflector, the first reflector is used to change the optical path of the third light beam so that the third light beam enters the beam combining element, and the second reflector is used to change the optical path of the fourth light beam so that the fourth light beam enters the beam combining element.
[0018] The beneficial effect of the optical system provided by the embodiment of the present application is that: the optical system of the embodiment of the present application is provided with an incident component, a first shaping component, a second shaping component and a beam combining component, and the incident component adjusts the polarization angle of the incident laser beam and then splits it into a first polarized beam and a second polarized beam. The light intensity regulator and beam expander of the first polarized beam are used by the first shaping component to adjust the light intensity and size, forming a third beam with a solid circular cross section that can adjust the light intensity and cross-sectional size. The second shaping component shapes the second polarized beam into a fourth beam with a ring-shaped cross section. The beam combining component then combines the third beam and the fourth beam into a flat-top beam, and the focusing lens focuses the flat-top beam to form a processing beam. Since the processing beam is formed by a flat-top beam, when the processing beam is used for processing, the energy distribution of the generated light spot is uniform, which is suitable for the transfer and removal of LED chips, avoids uneven stress, and is conducive to improving the yield of the process. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, 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 present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.
[0020] Figure 1 A schematic diagram of an optical system provided in an embodiment of the present application;
[0021] Figure 2 is the spot cross-section diagram of an ordinary Gaussian beam;
[0022] Figure 3 A cross-sectional view of a light spot of a fourth light beam of the optical system provided in an embodiment of the present application;
[0023] Figure 4 A cross-sectional view of a light spot of a third light beam of the optical system provided in an embodiment of the present application;
[0024] Figure 5 A rectangular spot cross-sectional view of a processing light beam of the optical system provided in an embodiment of the present application after being intercepted by a slit module;
[0025] Figure 6 A cross-sectional view of the light spot of the processing light beam of the optical system provided in an embodiment of the present application projected onto the processing plane.
[0026] Among them, the reference numerals in the figure are:
[0027] 10. Laser; 11. Laser beam;
[0028] 20. Incident component; 21. First half-wave plate; 22. First polarization beam splitter; 23. First polarized light beam; 24. Second polarized light beam;
[0029] 30. first shaping component; 31. light intensity regulator; 311. second half-wave plate; 312. second polarization beam splitter; 32. beam expander; 33. third light beam;
[0030] 40. second shaping component; 41. first aconic lens; 42. second aconic lens; 43. fourth light beam;
[0031] 50. beam combining assembly; 51. beam combining element; 52. focusing lens; 53. galvanometer; 54. slit module; 55. flat-top beam; 56. processing beam;
[0032] 60. first reflector;
[0033] 70. Second reflector. DETAILED DESCRIPTION
[0034] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.
[0035] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.
[0036] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.
[0037] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.
[0038] See also Figure 1The optical system provided by the embodiment of the present application is now described. The optical system provided by the embodiment of the present application includes an incident component 20, a first shaping component 30, a second shaping component 40 and a beam combining component 50.
[0039] The incident component 20 is a primary mechanism for receiving the laser beam 11 emitted by the laser 10 . The laser beam 11 emitted by the laser 10 is first incident into the incident component 20 .
[0040] Reference Figure 1 The incident component 20 includes a first half-wave plate 21 and a first polarization beam splitter prism 22 which are sequentially arranged on the optical path of the laser beam 11. The first half-wave plate 21 is used to adjust the polarization angle of the incident laser beam 11. The first polarization beam splitter prism 22 is used to split the laser beam 11 after the polarization angle is adjusted to generate a first polarization beam 23 and a second polarization beam 24 with different optical paths.
[0041] Since the first half-wave plate 21 and the first polarization beam splitter prism 22 are sequentially arranged on the optical path of the laser beam 11, when the laser 10 emits the laser beam 11, the laser beam 11 sequentially passes through the first half-wave plate 21 and the first polarization beam splitter prism 22. After the laser beam 11 passes through the first half-wave plate 21, its polarization angle changes, and then it is incident on the first polarization beam splitter prism 22 and is split into two light beams with different directions, namely, the first polarization light beam 23 and the second polarization light beam 24. It can be understood that the laser beam 11 emitted by the laser 10 is polarized light, specifically linearly polarized light.
[0042] In some embodiments, the first polarized light beam 23 is P light, and the second polarized light beam 24 is S light. The first polarization beam splitter prism 22 can separate the horizontal polarization and the vertical polarization of the laser beam 11, so the first polarized light beam 23 and the second polarized light beam 24 are horizontally polarized light (i.e., P light) and vertically polarized light (i.e., S light), respectively.
[0043] The first polarized light beam 23 and the second polarized light beam 24 separated from the first polarization beam splitter prism 22 are respectively incident on the first shaping component 30 and the second shaping component 40. Specifically, the first polarized light beam 23 is along the first direction, and the second polarized light beam 24 is along the second direction, and the first direction and the second direction form an angle. In some embodiments, the first direction and the second direction are perpendicular to each other.
[0044] Reference Figure 1 and Figure 2 The first shaping component 30 includes a light intensity regulator 31 and a beam expander 32 which are sequentially arranged in the optical path direction of the first polarized light beam 23. The light intensity regulator 31 is used to adjust the light intensity of the first polarized light beam 23, and the beam expander 32 is used to adjust the cross-sectional size of the first polarized light beam 23 transmitted through the light intensity regulator 31 to generate a third light beam 33 with a solid circular cross-section.
[0045] The intensity of the incident first polarized light beam 23 can be adjusted by the light intensity regulator 31, so that the intensity of the two subsequent light beams is uniform and the energy of the combined light beam is uniform. The first polarized light beam 23 after intensity adjustment is then incident on the beam expander 32, and the beam expander 32 adjusts the cross-sectional size of the light beam to produce a third light beam 33 with a solid circular cross-section. The cross-sectional size of the third light beam 33 can be adjusted so that it matches the hollow circular ring of the fourth light beam 43 generated by the second shaping component 40 during the subsequent beam combination, so as to avoid the overlap between the two, which may cause the overlap to be too high and cause uneven energy.
[0046] Reference Figure 1 and Figure 3 The second shaping component 40 is used to shape the incident second polarized light beam 24 to generate a fourth light beam 43 with a ring-shaped cross section. The second polarized light beam 24 is incident on the second shaping component 40 and generates a fourth light beam 43 with a ring-shaped cross section, that is, the fourth light beam 43 is hollow, which just matches the solid circle of the third light beam 33, and the solid circle can just fill the hollow part of the fourth light beam 43.
[0047] It should be noted that the second shaping component 40 can be directly disposed on the optical path of the second polarized light beam 24 , or the optical path direction of the second polarized light beam 24 can be changed through other structures and then guided to be incident on the second shaping component 40 .
[0048] Reference Figure 1 and Figure 4 The beam combining component 50 includes a beam combining element 51 and a focusing lens 52. The beam combining element 51 is used to coaxially combine the third light beam 33 and the fourth light beam 43 to generate a flat-top beam 55. The focusing lens 52 is used to focus the flat-top beam 55 to form a processing beam 56.
[0049] The third light beam 33 and the fourth light beam 43 are both incident on the beam combining element 51, and the beam combining element 51 coaxially combines the third light beam 33 and the fourth light beam 43 to generate a flat-top beam 55. The flat-top beam 55 is synthesized by the solid circular third light beam 33 and the hollow circular fourth light beam 43, and its cross section is a solid circle, and the intensity and energy distribution are uniform everywhere. The flat-top beam 55 is then focused by the focusing lens 52 to form a processing beam 56, which reduces the area and concentrates the energy. The processing beam 56 can be projected onto the surface of the workpiece to process the workpiece.
[0050] The beam combining element 51 may be a third polarization beam splitting prism.
[0051] Specifically, the workpiece may be an LED chip, which is processed by the processing light beam 56. Since the processing light beam 56 forms a light spot on the workpiece, the energy distribution is uniform everywhere, the LED chip absorbs the heat of the laser radiation uniformly, and its surface is not prone to uneven stress, thereby avoiding the LED chip from shifting, flipping, and chip breakage during the transfer process, and avoiding chip residue during the removal process of the LED chip. In addition, when performing solder trimming on the display backplane, since the solder absorbs the heat of the laser radiation uniformly, the surface morphology of the modified solder is better, which is convenient for secondary welding and is conducive to improving the yield of the process.
[0052] Reference Figure 1 The reflecting surface of the first polarization beam splitter prism 22 forms an angle of 45° with the optical axis of the laser beam 11, and the reflecting surface of the first polarization beam splitter prism 22 forms an angle of 45° with the optical axis of the second polarized light beam 24. The first polarized light beam 23 can pass through the first polarization beam splitter prism 22 along the direction of the laser beam 11, while the second polarized light beam 24 is reflected out by the reflecting surface, so that the directions of the first polarization light beam 23 and the second polarization light beam 24 are 90°, which is convenient for the subsequent control of the combination of the two light beams.
[0053] Each light-transmitting surface of the first polarization beam splitter prism 22 is coated with an anti-reflection film to reduce the reflected light on the prism surface, thereby increasing the light transmittance of the first polarization beam splitter prism 22 and reducing the stray light of the system.
[0054] Reference Figure 1 The surface of the first half-wave plate 21 is perpendicular to the optical axis of the laser beam 11 to ensure the adjustment of the polarization angle of the laser beam 11 .
[0055] The surface of the first half-wave plate 21 is coated with an anti-reflection film to reduce the reflected light on the surface of the first half-wave plate 21, thereby increasing the light transmittance of the first half-wave plate 21 and reducing the stray light of the system.
[0056] Reference Figure 1 The light intensity regulator 31 includes a second half-wave plate 311 and a second polarization beam splitter prism 312. The second half-wave plate 311, the second polarization beam splitter prism 312 and the beam expander 32 are sequentially arranged along the optical path direction of the first polarized light beam 23. The surface of the second half-wave plate 311 is perpendicular to the optical axis of the first polarized light beam 23. The transmission surface of the second polarization beam splitter prism 312 forms an angle of 45° with the optical axis of the first polarized light beam 23. The combination of the second half-wave plate 311 and the second polarization beam splitter prism 312 can adjust the light intensity of the light beam passing through. The light beam emitted from the light intensity regulator 31 is a solid circular light beam, which is then emitted into the beam expander 32. The beam expander 32 adjusts the cross-sectional size of the solid circular light beam to match the hollow portion of the circular ring of the fourth light beam 43 to fill the hollow portion. Specifically, the spot cross-section of the third light beam 33 is as follows: Figure 2 shown.
[0057] That is to say, through the light intensity regulator 31 and the beam expander 32, the light intensity and cross-sectional size of the third light beam 33 can be adjusted to match the light intensity and the hollow part of the cross section of the fourth light beam 43, so that the generated light beam is a flat-top beam 55 with uniform light intensity and a circular cross section.
[0058] Reference Figure 1 The beam expander 32 is coaxial with the first polarized light beam 23 to ensure the uniformity of the formed third light beam 33.
[0059] Reference Figure 1 The second shaping component 40 includes a first cone lens 41 and a second cone lens 42 which are sequentially arranged along the optical path of the second polarized light beam 24. The first cone lens 41 and the second cone lens 42 are symmetrically installed and the cone surfaces are close to each other. The distance between the first cone lens 41 and the second cone lens 42 can be adjusted within a set range. The second polarized light beam 24 first passes through the first cone lens 41 to generate a circular ring beam, and then passes through the second cone lens 42 to generate a collimated circular ring beam (i.e., the fourth light beam 43). Specifically, the spot cross section of the fourth light beam 43 is as follows: Figure 3 shown.
[0060] The bottom surfaces of the first cone lens 41 and the second cone lens 42 are parallel to each other, and the bottom surfaces are perpendicular to the optical axis of the second polarized light beam 24 .
[0061] The first cone lens 419 has an α angle of 5°, 10°, or 20°, and is used to generate a circular ring beam. The second cone lens 4210 has an α angle of 5°, 10°, or 20°, and is used to collimate the circular ring beam. The first cone lens 41 and the second cone lens 42 are installed horizontally symmetrically, and the distance between the cone surfaces of the two cone lenses can be moved within a set range L along the optical axis direction. Where D is the spot diameter of the incident light beam, n is the refractive index of the axon to the incident wavelength, and θ is the base angle of the axon.
[0062] Reference Figure 1 and Figure 6 The beam combining assembly 50 further includes a galvanometer 53. The focusing lens 52 focuses the processing light beam 56 onto the center of the lens of the galvanometer 53. The galvanometer 53 is used to reflect the processing light beam 56 onto a processing plane. The direction of the processing light beam 56 can be controlled by the galvanometer 53 to better process the workpiece. The processing plane can be an LED chip on a display back panel.
[0063] Reference Figure 1 , Figure 4 and Figure 5The beam combining component 50 also includes an adjustable slit module 54 located between the beam combining element 51 and the focusing lens 52. The slit module 54 is used to intercept the flat-top beam 55 so that the cross-section of the flat-top beam 55 incident on the focusing lens 52 is rectangular. The slit module 54 can intercept the generated flat-top beam 55, so that the light spot of the flat-top beam 55 changes from a circle to a rectangle, which is more suitable for the maintenance of LED chips. The slit module 54 is also called a slit module, which is adjustable and can adjust the size of the rectangle as needed. When the flat-top beam 55 with a rectangular cross-section passes through the focusing lens 52, the cross-section of the generated processing beam 56 is also rectangular, and of course, its energy density is higher.
[0064] In some embodiments, the focal length of the focusing lens 52 is f=1000 mm.
[0065] Reference Figure 1 , the embodiment of the present application further includes a first reflector 60 and a second reflector 70, the first reflector 60 is used to change the optical path of the third light beam 33 so that the third light beam 33 is incident on the beam combining element 51, and the second reflector 70 is used to change the optical path of the fourth light beam 43 so that the fourth light beam 43 is incident on the beam combining element 51. When installed, the first reflector 60 forms an angle of 45° with the optical axis of the first polarized light beam 23, and the second total reflector forms an angle of 45° with the optical axis of the second polarized light beam 24, and is used to reflect the split second polarized light beam 24 at an angle of 90° to the second shaping component 40. In some embodiments, the reflective surfaces of the first reflector 60 and the second reflector 70 are coated with a high reflective film.
[0066] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.
Claims
1. An optical system, characterized in that: include: An incident component, comprising a first half-wave plate and a first polarization beam splitter prism sequentially arranged on the optical path of the laser beam, wherein the first half-wave plate is used to adjust the polarization angle of the incident laser beam, and the first polarization beam splitter prism is used to split the laser beam after the polarization angle is adjusted to generate a first polarization beam and a second polarization beam with different optical paths; A first shaping component includes a light intensity regulator and a beam expander which are sequentially arranged in the light path direction of the first polarized light beam, wherein the light intensity regulator is used to adjust the light intensity of the first polarized light beam, and the beam expander is used to adjust the cross-sectional size of the first polarized light beam transmitted through the light intensity regulator to generate a third light beam with a solid circular cross-section; A second shaping component, used for shaping the incident second polarized light beam to generate a fourth light beam with a ring-shaped cross section; as well as The beam combining component comprises a beam combining element and a focusing lens, wherein the beam combining element is used to coaxially combine the third light beam and the fourth light beam to generate a flat-top beam, and the focusing lens is used to focus the flat-top beam to form a processing beam.
2. The optical system according to claim 1, characterized in that The first polarized light beam is P light, and the second polarized light beam is S light.
3. The optical system according to claim 1, characterized in that The reflection surface of the first polarization beam splitter prism forms an angle of 45° with the optical axis of the laser beam, and the reflection surface of the first polarization beam splitter prism forms an angle of 45° with the optical axis of the second polarized light beam.
4. The optical system according to claim 1, characterized in that A surface of the first half-wave plate is perpendicular to the optical axis of the laser beam.
5. The optical system according to claim 1, characterized in that The light intensity regulator includes a second half-wave plate and a second polarization beam splitter prism. The second half-wave plate, the second polarization beam splitter prism and the beam expander are arranged in sequence along the optical path direction of the first polarized light beam. The surface of the second half-wave plate is perpendicular to the optical axis of the first polarized light beam. The transmission surface of the second polarization beam splitter prism forms an angle of 45° with the optical axis of the first polarized light beam.
6. The optical system according to claim 1, characterized in that The beam expander is coaxial with the first polarized light beam.
7. The optical system according to claim 1, characterized in that The second shaping component includes a first cone lens and a second cone lens arranged in sequence along the optical path of the second polarized light beam. The first cone lens and the second cone lens are symmetrically installed and the cone surfaces are close to each other. The distance between the first cone lens and the second cone lens can be adjusted within a set range.
8. The optical system according to claim 1, characterized in that The beam combining assembly further includes a galvanometer, the focusing lens focuses the processing light beam to the center of a lens of the galvanometer, and the galvanometer is used to reflect the processing light beam to a processing plane.
9. The optical system according to claim 1, characterized in that The beam combining assembly further comprises an adjustable slit module located between the beam combining element and the focusing lens, wherein the slit module is used to intercept the flat-top beam so that the cross section of the flat-top beam incident on the focusing lens is rectangular.
10. The optical system according to claim 1, characterized in that It also includes a first reflector and a second reflector, the first reflector is used to change the optical path of the third light beam so that the third light beam enters the beam combining element, and the second reflector is used to change the optical path of the fourth light beam so that the fourth light beam enters the beam combining element.