Light source suitable for 3D printing and light curing equipment

Abstract

The utility model discloses a light source and photocuring equipment suitable for 3D printing, the light source comprises a substrate, the surface of the substrate is provided with light-emitting chips and a plurality of lenses, the center normal direction of each lens directly faces a group of light-emitting parts, each group of light-emitting parts comprises at least one light-emitting chip, and the light-emitting chips are arranged on the surface of the substrate. The light-emitting chips are chip-on-board (COB) devices, a shading partition plate is arranged between every two adjacent sets of light sources, the shading partition plates are aligned with the edges of the lenses, the COB assembling technology is utilized, the light source structure is simplified, the production cost of the light source is reduced, the manufacturing precision of the light source can be improved, the light-emitting angle and height of the light-emitting chips are fully controlled, and the light-emitting efficiency is improved. Therefore, the collimation and the light emitting uniformity of the light source are greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of 3D printing, and more specifically, to a light source and light curing equipment suitable for 3D printing. Background Art

[0002] The collimation and uniformity of the light source for 3D printing play a decisive role in the printing accuracy. The surface light source formed by the convex lens has a phenomenon that the light intensity is high at the optical axis of the convex lens, and the light intensity decreases as the distance from the optical axis increases. In this way, the irradiation light intensity of this surface light source varies within the same cross section. On the light-curing surface, the photosensitive material at the optical axis cures quickly, while the photosensitive material far from the optical axis cures slowly, causing deformation of the 3D printed body.

[0003] The factors that cause low collimation of the light source are mainly the following aspects, including the deviation of the center position of the lamp bead, the deviation of the height of the lamp bead, the deviation of the mounting position of the lamp bead, etc. Among them, due to the limitations of the assembly process of the lamp bead, the optical axis of the lamp bead after assembly often forms an angle with the center axis of the lens, or the height difference of the lamp bead is too large, resulting in low collimation of the light source.

[0004] Similarly, the assembly process of the lamp beads will also affect the uniformity of the light output. Conventional lamp beads are connected to the substrate by pasting. Due to the thickness of the pasting layer, the assembled lamp beads usually have a height difference of 0.3-0.5mm, which directly leads to poor final light output uniformity. A certain light-emitting device on the market has a visible gap in the light spot 20mm away from the light-emitting unit, and its uniformity is measured to be about 80%, which does not meet the requirements of 3D printing light sources.

[0005] Therefore, how to improve the collimation and uniformity of the light source to enhance 3D printing accuracy is a direction that needs to be improved in the industry. Utility Model Content

[0006] The utility model aims to overcome the defects of low light collimation and poor light uniformity of existing light emitting devices, and to provide a light source suitable for 3D printing, which reduces the height difference of the light source through the COB assembly process, thereby improving the light collimation and light uniformity.

[0007] In addition, the utility model also provides a light-curing device, which can be used to cure 3D printed products with good curing effect.

[0008] In order to solve the above technical problems, the utility model proposes the following light source suitable for 3D printing, including a substrate, a light-emitting chip and a plurality of lenses are mounted on the surface of the substrate, the center normal direction of each lens is facing a group of light-emitting parts, a group of light-emitting parts includes at least one light-emitting chip, and the light-emitting chip is a chip-on-board COB device. A light-shielding baffle is arranged between two adjacent groups of light sources, the light-shielding baffle is aligned with the edge of the lens, and the top surface of the light-shielding baffle abuts against the bottom surface of the lens, thereby improving the light-shielding effect. At the same time, the light-shielding baffle abuts against the lens and can also cover the light-emitting chip, achieving a packaging effect, and preventing impurities and dust from interfering with the light-emitting effect of the light-emitting chip.

[0009] Furthermore, a group of light-emitting elements includes a plurality of light-emitting chips, and the light-emitting chips are connected in parallel. Connecting the light-emitting chips in parallel can reduce the voltage difference between the light-emitting chips, making the brightness of the light-emitting chips more uniform, which is conducive to improving the uniformity of light output.

[0010] Furthermore, the plurality of light-emitting chips are arranged in a square or a circle.

[0011] Furthermore, a group of light-emitting elements includes 21 light-emitting chips, and the light-emitting chips are chips with a model of 6mil×20mil and a peak wavelength of 400-410nm.

[0012] Furthermore, the optical power difference between the light-emitting chips is less than 50 mW.

[0013] Furthermore, the height of the shading partition is 5-15 mm.

[0014] Furthermore, the lens height H1 is 7-12 mm, and a microstructure is provided on the upper portion of the lens. The microstructure is a hemispherical structure corresponding to a group of light sources, an aspherical structure formed by multiple arc surfaces, or a polygonal structure, and the height H2 of the microstructure is 2.3-3.7 mm.

[0015] Furthermore, the microstructure is a 10th-order even-order aspheric structure, and its equation is as follows:

[0016]

[0017] In the formula,

[0018] z is the sag, that is, the distance from a point on the aspherical surface to its reference plane;

[0019] c is the curvature of the aspheric surface, which is the inverse of the radius;

[0020] r is the distance from the section to the axis;

[0021] k is the cone coefficient;

[0022] Ai is the i-th order coefficient of the even-order aspheric surface, where i represents the order of the coefficient.

[0023] Furthermore, the lens is made of polymethyl methacrylate, glass, silicone, polycarbonate or crystal.

[0024] The utility model further proposes a light curing device, including a shell, in which a control unit and the above-mentioned light source suitable for 3D printing are arranged, and the control unit is communicatively connected with the light source, and the light emitting chip in the light source is controlled to be turned on and off by the control unit.

[0025] Due to the adoption of the above technical solution, compared with the prior art, the beneficial effects of the utility model are:

[0026] The utility model utilizes the COB assembly process, which not only simplifies the light source structure and reduces its production cost, but also improves the manufacturing accuracy of the light source and fully controls the light output angle and height of the light-emitting chip, so that the collimation and uniformity of the light source are greatly improved. This is of great significance and value for many applications that require a uniform light spot (such as 3D printing). BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0028] Figure 2 for Figure 1 Section view along line AA.

[0029] In the attached figure:

[0030] 1-substrate; 2-light-emitting chip; 3-lens; 4-light-shielding partition. DETAILED DESCRIPTION

[0031] The utility model is further described below in conjunction with specific implementation methods. The drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. In order to better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0032] The same or similar reference numerals in the drawings of the embodiments of the present utility model correspond to the same or similar parts; in the description of the present utility model, it should be understood that if the terms "front", "rear", "left", "right" and the like indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, it is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only used for exemplary explanations and cannot be understood as limitations on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances. In addition, in the present utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features.

[0033] Embodiment 1

[0034] See also Figure 1 and Figure 2 This embodiment provides a light source suitable for 3D printing, including a substrate 1, which can be a metal substrate, such as a copper substrate, a kovar alloy substrate, etc., or a ceramic substrate or an organic resin substrate. A light-emitting chip 2 and a plurality of lenses 3 are mounted on the surface of the substrate 1. The light-emitting chip 2 is a chip on board (COB) device. The center normal direction of each lens 3 faces a group of light-emitting components. A group of light-emitting components includes at least one light-emitting chip 2, and a light-shielding partition 4 is arranged between two adjacent groups of light-emitting components. The light-shielding partition 4 is aligned with the edge of the lens 3.

[0035] The light-emitting chip 2 is a violet LED chip, and the peak wavelength of the violet LED chip is 400-410nm, preferably 405nm, and can be adhered to the substrate 1 by conductive glue or non-conductive glue. When powered on, the light-emitting chip 2 can emit violet light, which is suitable for use with 3D printing equipment to cure 3D printed products. Of course, this embodiment can also be applied in other fields. For example, in dentistry, the curing of UV glue also often uses violet light or ultraviolet light to accelerate curing. This embodiment can be adaptively adjusted to obtain a curing light source that can be used in dentistry.

[0036] A light shielding baffle 4 is provided between two adjacent groups of light emitting parts, and the light shielding baffle 4 can prevent the light emitted by one group of light emitting parts from being emitted to the lens 3 at an adjacent position, thereby forming an uneven light spot. The side wall of the light shielding baffle 4 is preferably coated with a reflective layer, so that the light emitted by one group of light emitting parts is emitted along its optical axis in a nearly parallel light manner, and passes through the lens 3 directly opposite to the group of light emitting parts. The light shielding baffle 4 is aligned with the edge of the lens 3, and the top surface of the light shielding baffle 4 abuts against the bottom surface of the lens 3, thereby improving the light shielding effect. At the same time, the light shielding baffle 4 abuts against the lens 3, and can also cover the light emitting chip 2, thereby achieving a packaging effect, and preventing impurities and dust from interfering with the light emitting effect of the light emitting chip 2.

[0037] It should be noted that the lens 3 can be a circular lens projected as a circle, or a square lens projected as a square. The shape of the lens 3 matches the shape of the light-emitting chip 2 or the shape formed by a plurality of the light-emitting chips 2. For example, if the light-emitting chip 2 is circular, or a plurality of the light-emitting chips 2 are arranged in a circle, the lens 3 is preferably a circular lens. If a plurality of the light-emitting chips 2 are arranged in a square, the lens 3 is preferably a square lens.

[0038] In a specific application embodiment, the substrate 1 is 100mm×100mm, and the substrate 1 is divided into 10×10 squares by a shading partition 4, the thickness of the shading partition 4 is 1mm, and each of the squares is 9mm×9mm. A light-emitting chip 2 is arranged in each of the squares, the specification of the light-emitting chip 2 is 45×45mil, the peak wavelength is 405nm, and its power is 1000mW under the condition of 500mA current. Each light-emitting chip 2 is connected in parallel, and after power is turned on, the irradiation intensity and light uniformity are tested at 10mm, 20mm, 30mm, 40mm and 50mm from the top surface of the lens 3, respectively. The test results are shown in the following table:

[0039] Table 1 Test results of Example 1

[0040]

[0041] The above results show that the light uniformity of this embodiment at 20mm from the top surface of the lens 3 exceeds 97%, which is a significant improvement compared to the prior art. This embodiment improves the assembly accuracy of the light-emitting chip 2 through the COB assembly technology, ensures that the light-emitting angle of the light-emitting chip 2 is parallel to the central axis of the lens 3, and effectively reduces the height difference between multiple light-emitting chips 2, making the light emission effect more uniform.

[0042] Embodiment 2

[0043] See also Figure 1 and Figure 2This embodiment provides another light source suitable for 3D printing. Different from the first embodiment, the light emitting chip 2 used in this embodiment is 6mil×20mil, with a peak wavelength of 405±5nm. In this embodiment, 21 light emitting chips 2 as described above are arranged in a group of light emitting parts. The light emitting chips 2 are arranged in a square in 7 rows and 3 columns. The light emitting chips 2 are connected in parallel, and their power is 80mW under the condition of 50mA current. The light emitting chips 2 are connected by wires.

[0044] It should be noted that, according to the actual application scenario, the light-emitting chips 2 can also be connected in series, or partially in series and partially in parallel. The parallel connection scheme is preferred because the parallel connection scheme can reduce the voltage difference between the light-emitting chips 2, making the brightness of the light-emitting chips 2 more uniform, which is conducive to improving the overall light uniformity of the light source.

[0045] The size of the substrate 1 is 224×144mm, about 10.1 inches, and is divided into a number of squares by the light-shielding partition 4. The size of each square is 15×15mm, and the thickness of the light-shielding partition 4 is 1mm. The lens 3 is arranged on the top surface of the light-shielding partition 4 and abuts against the light-shielding partition 4. It is measured that there is no gap visible to the naked eye in the light spot of the light source at a distance of 20mm from the light-emitting element, and the light uniformity of the light source is measured to be about 92%, which is 12% higher than the existing technology and meets the requirements of 3D printing light sources.

[0046] The use of multiple smaller light emitting chips 2 can also improve the light uniformity of the light source as a whole. Compared with the first embodiment, although the light uniformity of this embodiment does not exceed 95%, it can still meet the requirements of the 3D printing light source. In addition, the smaller light emitting chip 2 is much cheaper than the larger light emitting chip 2, so the production cost can be effectively reduced.

[0047] At the same time, the collimation of this embodiment is also improved compared with the prior art. An existing rectangular light source with a (diagonal) size of 10.1 inches is selected as a control example. The length and width of the receiving light spot are measured at 10mm, 20mm, 30mm, 40mm and 50mm from the light source. The test results are shown in Table 2 below:

[0048] Table 2. Collimation test results of control example

[0049]

[0050] This embodiment was selected to carry out a collimation test under the same conditions, and the test results are shown in Table 3 below:

[0051] Table 3 Collimation test results of Example 2

[0052]

[0053] It can be seen that the size of the light spot projected by the second embodiment increases proportionally with the increase of the receiving distance, which reflects that the collimation of the light source described in the second embodiment is good. Collimation is one of the important parameters affecting the accuracy of 3D printing. Improving the collimation of the light source is conducive to improving the accuracy of 3D printed products.

[0054] Of course, it should be noted that the height of the light shielding partition 4 can be adjusted according to the distance between the lens 3 and the light emitting element. The height of the light shielding partition 4 can be adjusted within the range of 5-15 mm.

[0055] Furthermore, this embodiment also limits the optical power difference between each of the light-emitting chips 2 to less than 50mW. The applicant has found that the brightness uniformity of the light-emitting chips 2 on the module is also very important to the final light uniformity. The greater the voltage difference of the light-emitting chips 2 between the parallel circuits, the greater the actual working current difference. Based on this, limiting the optical power difference between each of the light-emitting chips 2 to less than 50mW is conducive to controlling the current difference between the parallel currents, thereby improving the light uniformity of the light source.

[0056] Embodiment 3

[0057] See also Figure 1 and Figure 2 This embodiment provides another light source suitable for 3D printing. The difference from the first embodiment is that the height H1 of the lens 3 used in this embodiment is 7 mm. The lens 3 can be divided into an upper and a lower part, wherein the upper part has a microstructure, and the microstructure is a 10th-order even-order aspheric structure, and the microstructure satisfies the following equation:

[0058]

[0059] In the formula,

[0060] z is the sag, that is, the distance from a point on the aspherical surface to its reference plane;

[0061] c is the curvature of the aspheric surface, which is the inverse of the radius;

[0062] r is the distance from the section to the axis;

[0063] k is the cone coefficient;

[0064] A i is the i-th order coefficient of the even-order aspheric surface, where i represents the order of the coefficient.

[0065] The height H2 of the microstructure is 2.3 mm, which increases or decreases in proportion to the overall height H1 of the lens 3. For example, in this embodiment, when the height H1 of the lens 3 is 7 mm, the height H2 of the microstructure is preferably 2.3 mm. In some other embodiments, when the height H1 of the lens 3 is 12 mm, the height H2 of the microstructure is preferably 3.7 mm.

[0066] In some other embodiments, the height H1 of the lens 3 may also be 8 mm, 9 mm, 10 mm, 11 mm or any value between 7-12 mm.

[0067] In some other embodiments, the height H2 of the microstructure may also be any value between 2.3-3.7 mm.

[0068] Of course, in some other embodiments, the microstructure can also be a hemispherical structure or a polygonal structure corresponding to a group of light sources. The microstructure can change the incident angle of the light emitted by the light-emitting chip 2 reaching the exit interface, so that the incident angle is less than the critical angle causing total reflection, thereby achieving the purpose of increasing the light output rate. When reaching the exit interface (i.e., the air interface of the lens 3), the microstructure with a certain curvature further changes the incident angle, making it much smaller than the critical angle, avoiding the occurrence of total reflection and increasing the exiting luminous flux. Whether it is the 10th-order even-order aspherical structure described in this embodiment, or other hemispherical structures, or polygonal structures, the same effect can be achieved.

[0069] In this embodiment, the lens 3 is made of polymethyl methacrylate (PMMA). Of course, in some other embodiments, the lens 3 may also be made of other organic or inorganic materials, such as glass, silicone, polycarbonate or crystal.

[0070] Embodiment 4

[0071] Based on the light source in the above embodiment, the present application further provides a light-curing device, which can be installed in a 3D printing tool. The light-curing device includes a housing, in which a control unit and a light source suitable for 3D printing based on the above embodiment are arranged, and the control unit is communicatively connected with the light source.

[0072] Therefore, the light curing device can have all the technical features and beneficial effects of the above-mentioned light source, which will not be repeated here.

[0073] In the specific contents of the above-mentioned specific implementation methods, the various technical features can be combined in any non-contradictory manner. In order to make the description concise, not all possible combinations of the above-mentioned technical features are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0074] Obviously, the above embodiments of the utility model are only examples for clearly explaining the utility model, and are not intended to limit the implementation methods of the utility model. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the utility model should be included in the protection scope of the claims of the utility model.

Claims

1. A light source suitable for 3D printing, comprising a substrate (1), a light-emitting chip (2) and a plurality of lenses (3) being mounted on the surface of the substrate (1), characterized in that: The center normal direction of each lens (3) faces a group of light-emitting components, wherein a group of light-emitting components comprises at least one light-emitting chip (2), wherein the light-emitting chip (2) is a chip-on-board (COB) device, and a light-shielding partition (4) is provided between two adjacent groups of light-emitting components, wherein the light-shielding partition (4) is aligned with the edge of the lens (3).

2. The light source suitable for 3D printing according to claim 1, characterized in that: A group of light-emitting elements comprises a plurality of light-emitting chips (2), wherein the light-emitting chips (2) are connected in parallel.

3. The light source suitable for 3D printing according to claim 2, characterized in that: The multiple light-emitting chips (2) are arranged in a square or a circle.

4. The light source suitable for 3D printing according to claim 2 or 3, characterized in that: A group of light-emitting components comprises 21 light-emitting chips (2), wherein the light-emitting chips (2) are chips with a model of 6 mil×20 mil and a peak wavelength of 400-410 nm.

5. The light source suitable for 3D printing according to claim 4, characterized in that: The optical power difference between the light-emitting chips (2) is less than 50 mW.

6. The light source suitable for 3D printing according to claim 1, characterized in that: The height of the light-shielding partition (4) is 5-15 mm.

7. The light source suitable for 3D printing according to claim 1, 5 or 6, characterized in that: The height of the lens (3) is 7-12 mm. The upper part of the lens (3) has a microstructure. The microstructure is a hemispherical structure corresponding to a group of light sources, a non-spherical structure formed by multiple arc surfaces, or a multi-prism structure. The height of the microstructure is 2.3-3.7 mm.

8. The light source suitable for 3D printing according to claim 7, characterized in that: The microstructure is a 10th-order even-order aspherical structure.

9. The light source suitable for 3D printing according to claim 7, characterized in that: The lens (3) is made of polymethyl methacrylate, glass, silicone, polycarbonate or crystal.

10. A light curing device, characterized in that: It comprises a shell, in which a control unit and a light source suitable for 3D printing according to any one of claims 1 to 9 are arranged, and the control unit is communicatively connected with the light source.

Images