Micro-led light source module, preparation method and 3D printing equipment

Abstract

The application provides a micro LED light source module and a preparation method and a 3D printing device, and comprises the following steps: providing a sapphire substrate to be cut, the sapphire substrate is a C-surface sapphire substrate, the flat edge direction of the sapphire substrate is parallel to the A-axis direction of the sapphire substrate, and a plurality of micro LED light emitting structures are formed on the sapphire substrate; the splicing surface is arranged on a non-inclined cleavage surface of the sapphire substrate, the non-inclined cleavage surface is parallel to the A surface of the flat edge direction, the A surface is perpendicular to the C surface, and the cutting path is arranged on the splicing surface; the sapphire substrate is cut along the cutting path to obtain a plurality of splicing units, each splicing unit comprises at least one splicing surface, each splicing unit comprises a plurality of micro LED light emitting structures; and the plurality of splicing units are spliced, any adjacent splicing units are mutually adhered through the splicing surface, and a micro LED light bar is formed. The A surface is used as the splicing surface, the cutting path is arranged, the splicing unit obtains a vertical section, the plurality of splicing units are adhered through the vertical section, and the micro LED light bar without splicing seams is prepared.

Description

Technical Field

[0001] This invention relates to the field of light-emitting technology, and in particular to a micro-LED light source module and its preparation method, as well as 3D printing equipment. Background Technology

[0002] Micro-LEDs (miniature light-emitting diodes) have become an important development direction for next-generation display technology due to their superior performance, including high brightness, high contrast, low power consumption, and long lifespan. Photopolymerization 3D printing, as one of the fastest-growing additive manufacturing technologies, is considered a future direction for display and intelligent manufacturing when combined with micro-LED technology. In photopolymerization 3D printing applications, as the required 3D printing area continues to increase, the length requirements for micro-LED light strips are also becoming longer.

[0003] Currently, sapphire is typically used as the epitaxial growth substrate for microLED chips in microLED light strips. Sapphire (α-Al2O3) belongs to the hexagonal crystal system and has an anisotropic crystal structure. Due to the special nature of the sapphire crystal lattice structure, when it is cut to obtain light strip splicing units, cracks will extend along specific crystal planes (i.e., cleavage planes). Research has found that when sapphire substrates are cut using conventional cutting methods, the cut surface is often not perpendicular, but rather produces a certain oblique crack angle. The size and direction of this oblique crack angle are affected by factors such as the substrate crystal orientation and thickness, and are uncertain and difficult to control precisely. This oblique crack phenomenon of the cut surface affects the assembly accuracy between multiple light strip units when splicing them to form microLED light strips, forcing the splicing seam to become larger, which in turn leads to a reduction in the effective light-emitting area. In addition, the oblique cut surface means that there are sharp corners at the cut position, and stress concentration is prone to occur at sharp corners, resulting in a decrease in the mechanical strength of the splicing unit after cutting and making it more susceptible to breakage. Furthermore, the tilted cross-section may cause unnecessary reflections or scattering inside the micro-LED light strip, resulting in increased stray light and affecting beam collimation and light energy utilization.

[0004] Therefore, how to obtain LED strip splicing units with vertical cross-sections (splicing surfaces) through reasonable crystal orientation selection and cutting process design, and achieve high-precision micro-LED strip splicing with small splicing seams, remains a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] This invention provides a micro-LED light source module and its preparation method, as well as a 3D printing device. When the cutting path is set parallel to the flat edge direction, the cutting cross-section is surface A, which is perpendicular to surface C. The splicing unit obtains a vertical cross-section of 90°±0.5°. Multiple splicing units are attached through this vertical cross-section to achieve seamless splicing of micro-LED light strips.

[0006] In one embodiment of the present invention, a method for preparing a micro LED light strip is provided, the method comprising: A sapphire substrate to be cut is provided. The sapphire substrate is a C-plane sapphire substrate. The flat edge direction of the sapphire substrate is parallel to the A-axis direction of the sapphire substrate. Multiple micro-LED light-emitting structures are formed on the sapphire substrate. The splicing surface is set on the non-oblique crack surface of the sapphire substrate. The non-oblique crack surface is surface A, which is parallel to the direction of the flat edge. Surface A is perpendicular to surface C, and the cutting path is set on the splicing surface. The sapphire substrate is cut along the cutting path to obtain multiple splicing units, each splicing unit including at least one splicing surface, and each splicing unit including multiple micro-LED light-emitting structures; Multiple splicing units are spliced ​​together, and any adjacent splicing units are bonded together through the splicing surface to form a micro LED light strip.

[0007] As an optional technical solution, setting the cutting path on the splicing surface includes: The C-plane orientation of the sapphire substrate was determined using X-ray diffraction. The splicing surface is aligned with the cleavage direction of the C surface.

[0008] As an optional technical solution, the flat edge direction of the sapphire substrate is parallel to the cleavage direction of the C-plane.

[0009] As an optional technical solution, cutting the sapphire substrate along the cutting path includes: Laser cutting is used to cut along the cutting path, so that the cut surface extends along the non-oblique crack surface to form a vertical cross-section.

[0010] As an optional technical solution, the angle between the splicing surface and the surface of the sapphire substrate is 90°±0.5°.

[0011] As an optional technical solution, after splicing multiple splicing units, the splicing gap between adjacent splicing units is less than or equal to half a pixel width.

[0012] As an optional technical solution, splicing multiple splicing units includes: Arrange the multiple splicing units along the length direction; An adhesive layer is applied to the splicing surface, and the adhesive layer is cured to fix the splicing surfaces of adjacent splicing units together.

[0013] As an optional technical solution, the adhesive layer includes optically transparent adhesive or UV-curable adhesive.

[0014] The present invention also provides a micro-LED light source module, including a micro-LED light strip prepared by the preparation method described above.

[0015] The present invention also provides a 3D printing device, including the micro-LED light source module as described above.

[0016] In summary, this invention provides a micro-LED light source module, its fabrication method, and a 3D printing device. By selecting a sapphire substrate with surface C (0001) and aligning its flat edge direction parallel to the A-axis direction, the splicing surface is set on surface A (11-20) parallel to the flat edge direction. Surface A is perpendicular to surface C and is a non-oblique crack surface. Cutting is performed using this splicing surface as the cutting path, resulting in splicing units with a vertical cross-section of 90°±0.5°. Multiple splicing units are bonded together through this vertical cross-section to form a micro-LED light strip with a splicing seam width less than or equal to half a pixel. The fabrication method of this invention fully utilizes the anisotropic properties of sapphire crystals. Through reasonable crystal orientation selection and cutting path design, it fundamentally solves problems such as poor splicing accuracy, decreased mechanical strength, and increased stray light caused by the tilt of the cutting cross-section. This achieves the fabrication of a high-precision, high-efficiency, and high-reliability micro-LED strip light source, which is particularly suitable for photopolymerization 3D printing equipment with high requirements for light source collimation and energy utilization. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating the preparation method of a micro LED light strip according to one embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the hexagonal crystal system of the sapphire substrate of the present invention.

[0020] Figure 3 This is a top view of a sapphire substrate to be cut according to an embodiment of the present invention.

[0021] Figure 4 This is a schematic diagram of multiple splicing units spliced ​​together to form a micro LED light strip in one embodiment of the present invention.

[0022] Figure 5 This is a photograph of the actual product after the splicing unit of the present invention has been cut. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0024] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0025] It should be understood that when describing the structure of a component, when referring to a layer or region as being "above" or "on top of" another layer or region, it can mean that it is directly above the other layer or region, or that it contains other layers or regions between it and the other layer or region. Furthermore, if the component is flipped over, that layer or region will be located "below" or "under" the other layer or region.

[0026] This invention provides a micro-LED light source module and its fabrication method, as well as a 3D printing device. By selecting a sapphire substrate with surface C (0001) and aligning its flat edge direction parallel to the A-axis direction, the splicing surface is set on surface A (11-20) parallel to the flat edge direction. Surface A is perpendicular to surface C and is a non-oblique crack surface. Multiple splicing units are obtained by cutting along a cutting path set on this splicing surface. Each splicing unit includes a vertical cross-section of 90°±0.5°. Multiple splicing units are bonded together through this vertical cross-section to achieve a seamlessly spliced ​​micro-LED light strip.

[0027] like Figure 1 As shown, in one embodiment of the present invention, a method for preparing a micro LED light strip is provided. The preparation method 1000 includes: A sapphire substrate to be cut is provided. The sapphire substrate is a C-plane (0001) sapphire substrate. The flat edge direction of the sapphire substrate is parallel to the A-axis direction of the sapphire substrate. Multiple micro-LED light-emitting structures are formed on the sapphire substrate. The splicing surface is set on the non-oblique crack surface of the sapphire substrate. The non-oblique crack surface is surface A (11-20) which is parallel to the flat edge direction. Surface A is perpendicular to surface C, and the cutting path is set on the splicing surface. The sapphire substrate is cut along the cutting path to obtain multiple splicing units. Each splicing unit includes at least one splicing surface and multiple micro-LED light-emitting structures. Multiple splicing units are spliced ​​together, and any adjacent splicing units are bonded together through splicing surfaces to form micro LED light strips.

[0028] The following will combine Figures 2 to 5 illustrate Figure 1 The preparation method in [the text].

[0029] like Figure 2 and Figure 3 As shown, a sapphire substrate 100 to be cut is provided. The sapphire substrate 100 is a C-plane (0001) sapphire substrate, meaning its main surface is oriented with a C-plane crystal. The sapphire substrate 100 has a flat edge, the direction of which is parallel to the A-axis direction of the sapphire crystal. According to the crystallographic properties of sapphire, the A-axis direction is perpendicular to the A-plane (11-20), and the A-plane (11-20) is perpendicular to the C-plane (0001), and the A-plane is a non-oblique cleft surface.

[0030] Multiple micro-LED light-emitting structures 12 are formed on a sapphire substrate 100 using a metal-organic chemical vapor deposition (MOCVD) process. Each micro-LED light-emitting structure 12 comprises a first semiconductor layer, an active light-emitting layer, and a second semiconductor layer stacked sequentially. The first semiconductor layer is an n-type GaN layer, the active light-emitting layer is a multiple quantum well (MQW) structure, and the second semiconductor layer is a p-type GaN layer. The active light-emitting layer emits light at a wavelength of 260–800 nm, making it suitable as an imaging light source for 2D and 3D printing equipment.

[0031] The splicing surface 11a is set on the non-oblique crack surface of the sapphire substrate 100. Specifically, surface A (11-20) parallel to the flat edge direction is selected as the non-oblique crack surface, and surface A is perpendicular to surface C (0001). Surface A is used as the splicing surface 11a, and the cutting path is set on the splicing surface 11a.

[0032] To ensure precise alignment between the cutting path and the crystal cleavage direction, this embodiment also includes: The C-plane crystal orientation of the sapphire substrate 100 was determined using X-ray diffraction. The splicing surface 11a was aligned with the cleavage direction of the C-plane. Since the flat edge direction of the sapphire substrate 100 is parallel to the A-axis direction, and the A-axis direction is perpendicular to the A-plane (11-20), and the A-plane (11-20) is perpendicular to the C-plane (0001), there is a definite geometric relationship between the flat edge direction and the cleavage direction of the C-plane, which allows for precise alignment.

[0033] The sapphire substrate 100 is cut along the cutting path set on surface A. In this embodiment, laser cutting technology is used, specifically an ultrafast laser with a pulse width in the femtosecond or picosecond range. During the cutting process, the laser focus is controlled within the sapphire substrate 100, the pulse energy is controlled between 0.1W and 1W, and multi-focus cutting technology is used to control the crack direction, so that the cut surface extends along the non-oblique crack surface, forming a vertical cross-section.

[0034] In other embodiments of the present invention, a multi-pass cutting process is employed. First, a modified layer is formed inside the sapphire substrate 100 using a laser energy of 0.3W, and then an extended cutting is performed using a laser energy of 0.8W, further improving the perpendicularity and surface finish of the cut surface. Measurements show that the angle between the perpendicular cut obtained using the multi-pass cutting process and the surface of the spliced ​​sapphire substrate 100 can be controlled within the range of 90°±0.5°, preferably within 90°±0.3°.

[0035] like Figure 3 , Figure 4 and Figure 5 As shown, the sapphire substrate 100 is divided into multiple splicing units 10 through the above-described cutting process. Each splicing unit 10 includes at least one splicing surface 11a, and each splicing unit 10 contains multiple micro-LED light-emitting structures 12. The multiple micro-LED light-emitting structures 12 are arranged in an array on the light-emitting surface of each splicing unit 10, for example. Furthermore, each micro-LED light-emitting structure 12 can be regarded as a pixel of the micro-LED strip light source subsequently obtained by splicing multiple splicing units 10. The distance between the center lines of any two adjacent micro-LED light-emitting structures 12 in the row direction is called the pixel width.

[0036] The cut surface formed on the side of the splicing unit 10 after cutting is the splicing surface 11a. The angle between the splicing surface 11a and the surface of the splicing sapphire substrate 11 included in the splicing unit 10 is 90°±0.5°, thus making the splicing surface 11a a vertical section. (Refer to...) Figure 5 The vertical cross section of the splicing unit 10 formed after cutting the sapphire substrate 100 according to the cutting line of this application is 90.43°. That is, by setting the cutting path with surface A (11-20) parallel to the flat edge direction, the splicing surface of the splicing unit 10 can form a vertical cross section.

[0037] It is understood that each splicing unit 10 includes at least one splicing surface 11a. When the splicing unit 10 is located at both ends of the micro LED light strip, its splicing sapphire substrate 11 has only one splicing surface 11a; when the splicing unit 10 is located in the middle part of the micro LED light strip, it includes two splicing surfaces 11a located at both ends of the splicing sapphire substrate 11.

[0038] Continue to refer to Figure 4 Multiple splicing units 10 are arranged along the length direction, with the splicing surfaces 11a of adjacent splicing units 10 facing each other. An adhesive layer 13, which is an optically transparent adhesive or a UV-curable adhesive, is placed between adjacent splicing surfaces 11a. The splicing surfaces 11a of adjacent splicing units 10 are then bonded together using the adhesive layer 13. After the adhesive layer 13 is cured, a fixed connection is formed, resulting in a micro-LED light strip or a micro-LED light source module.

[0039] After the stitching is completed, the width of the stitching seam between adjacent stitching units 10 is less than or equal to half a pixel width, thus achieving stitching.

[0040] This invention also provides a micro-LED light source module, which includes a micro-LED light strip fabricated using method 100. The micro-LED light strip has multiple splicing units 10, with adjacent splicing units 10 bonded together by a vertical splicing surface 11a, and the splicing seam width being less than or equal to half a pixel width. Here, the pixel width is defined as the distance between the centers of any two adjacent micro-LED light-emitting structures 12 in the row direction, typically 1-10 micrometers, suitable for high-precision applications.

[0041] The present invention also provides a 3D printing device, which includes a micro-LED light source module as described in Example 3. The emission wavelength of the micro-LED light source module is 260~800nm, and it can be used as an imaging light source for both 2D and 3D printing devices.

[0042] In summary, this invention provides a micro-LED light source module, its fabrication method, and a 3D printing device. By selecting a sapphire substrate with surface C (0001) and aligning its flat edge direction parallel to the A-axis direction, the splicing surface is set on surface A (11-20) parallel to the flat edge direction. Surface A is perpendicular to surface C and is a non-oblique crack surface. Cutting is performed using this splicing surface as the cutting path, resulting in splicing units with a vertical cross-section of 90°±0.5°. Multiple splicing units are bonded together through this vertical cross-section to form a micro-LED light strip with a splicing seam width less than or equal to half a pixel. The fabrication method of this invention fully utilizes the anisotropic properties of sapphire crystals. Through reasonable crystal orientation selection and cutting path design, it fundamentally solves problems such as poor splicing accuracy, decreased mechanical strength, and increased stray light caused by the tilt of the cutting cross-section. This achieves the fabrication of a high-precision, high-efficiency, and high-reliability micro-LED strip light source, which is particularly suitable for photopolymerization 3D printing equipment with high requirements for light source collimation and energy utilization.

[0043] The present invention has been described by the above-described embodiments; however, these embodiments are merely examples for implementing the present invention. Furthermore, the technical features involved in the different embodiments of the present invention described above can be combined with each other as long as they do not conflict with each other. It must be pointed out that the disclosed embodiments do not limit the scope of the present invention. On the contrary, any modifications and refinements made without departing from the spirit and scope of the present invention are within the scope of patent protection of the present invention.

Claims

1. A method for preparing a micro LED light strip, characterized in that, The preparation method includes: A sapphire substrate to be cut is provided. The sapphire substrate is a C-plane sapphire substrate. The flat edge direction of the sapphire substrate is parallel to the A-axis direction of the sapphire substrate. Multiple micro-LED light-emitting structures are formed on the sapphire substrate. The splicing surface is set on the non-oblique crack surface of the sapphire substrate. The non-oblique crack surface is surface A, which is parallel to the direction of the flat edge. Surface A is perpendicular to surface C, and the cutting path is set on the splicing surface. The sapphire substrate is cut along the cutting path to obtain multiple splicing units, each splicing unit including at least one splicing surface, and each splicing unit including multiple micro-LED light-emitting structures; Multiple splicing units are spliced ​​together, and any adjacent splicing units are bonded together through the splicing surface to form a micro LED light strip.

2. The preparation method according to claim 1, characterized in that, Setting the cutting path on the splicing surface includes: The C-plane orientation of the sapphire substrate was determined using X-ray diffraction. The splicing surface is aligned with the cleavage direction of the C surface.

3. The preparation method according to claim 2, characterized in that, The flat edge direction of the sapphire substrate is parallel to the cleavage direction of the C-plane.

4. The preparation method according to claim 1, characterized in that, Cutting the sapphire substrate along the cutting path includes: Laser cutting is used to cut along the cutting path, so that the cut surface extends along the non-oblique crack surface to form a vertical cross-section.

5. The preparation method according to claim 1, characterized in that, The angle between the splicing surface and the surface of the sapphire substrate is 90°±0.5°.

6. The preparation method according to claim 1, characterized in that, After multiple splicing units are spliced ​​together, the splicing gap between adjacent splicing units is less than or equal to half a pixel width.

7. The preparation method according to claim 1, characterized in that, The splicing of multiple splicing units includes: Arrange the multiple splicing units along the length direction; An adhesive layer is applied to the splicing surface, and the adhesive layer is cured to fix the splicing surfaces of adjacent splicing units together.

8. The preparation method according to claim 7, characterized in that, The adhesive layer includes optically transparent adhesive or UV-curable adhesive.

9. A micro-LED light source module, characterized in that, The microLED light source module includes a microLED light strip manufactured using the method described in any one of claims 1-8.

10. A 3D printing device, characterized in that, Includes the micro-LED light source module as described in claim 9.

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