Light source assembly and 3D printer

Abstract

According to the light source assembly and the 3D printer, light is homogenized and collimated mainly through mutual cooperation of a light transmitting assembly and a reflecting assembly, meanwhile, light loss is reduced, the light utilization rate is increased, uneven projection light is avoided, and uniform curing of printing resin is facilitated. According to the main technical scheme, the light source assembly is used for the 3D printer and comprises a light emitting assembly, a light transmitting assembly and a reflecting assembly; the light-emitting assembly and the reflection assembly are arranged on the two opposite sides of the light-transmitting assembly. The reflecting assembly is matched with the light-transmitting assembly, so that light emitted by the light-emitting assembly is refracted by the light-transmitting assembly and reflected by the reflecting assembly to be projected. The 3D printer is mainly used for 3D printing.

Description

Technical Field

[0001] The present invention relates to the field of 3D printing technology, and in particular, to a light source assembly and a 3D printer. Background Art

[0002] In a stereolithography 3D printer, a material tank is placed on the display screen of the printer after being filled with resin. The light source is located on the side of the display screen opposite to the material tank. The light beam of the light source is projected onto the display screen, and the projected light covers the entire display area of the display screen. Then, the light passes through the pattern on the display screen and is projected onto the printing resin in the material tank, so that the printing resin is cured layer by layer according to the preset pattern.

[0003] The collimation degree of the light with the display screen and the uniformity of the light beam have a direct impact on the curing of the printing resin. The collimation degree of the light with the display screen affects the forming accuracy of the printing resin, and the uniformity of the light beam affects the uniformity of the curing of the printing resin. In the prior art, since the light beam includes light rays of multiple angles, in order to ensure that the collimated light is as perpendicular to the display screen as possible, the stray light in the light is first filtered, and then the filtered light is collimated, so that part of the light is intercepted and cannot be projected, resulting in a decrease in the projected light intensity and an inability to ensure the uniformity of the projected light, affecting the curing effect of the printing resin. Summary of the Invention

[0004] In view of this, the present invention provides a light source assembly and a 3D printer, mainly through the mutual cooperation of a light-transmitting component and a reflecting component, while making the light uniform and collimated, reducing light loss, increasing light utilization rate, avoiding uneven projected light, and contributing to the uniform curing of the printing resin.

[0005] To achieve the above object, the present invention mainly provides the following technical solutions:

[0006] On the one hand, the present invention provides a light source assembly for a 3D printer, including:

[0007] A light-emitting component, a light-transmitting component, and a reflecting component;

[0008] The light-emitting component and the reflecting component are arranged on opposite sides of the light-transmitting component;

[0009] The reflecting component cooperates with the light-transmitting component to project the light emitted by the light-emitting component after refraction by the light-transmitting component and reflection by the reflecting component.

[0010] Among them, the light-transmitting component includes a convex surface and a bottom surface opposite to each other, the reflecting component includes a concave surface, the light-emitting component is correspondingly arranged with the bottom surface, and the concave surface is correspondingly arranged with the convex surface;

[0011] The light is refracted through the convex surface and the bottom surface, and the light is reflected through the concave surface.

[0012] Among them, the angle β between the tangent plane of the vertex of the convex surface and the horizontal plane is greater than or equal to 30° and less than 45°;

[0013] Or, the angle β between the tangent plane of the vertex of the convex surface and the horizontal plane is greater than 45° and less than 90°;

[0014] Or, the angle β between the tangent plane of the vertex of the convex surface and the horizontal plane is equal to 45°.

[0015] Among them, the angle between the tangent plane of the vertex of the convex surface and the horizontal plane is β, and the angle γ between the tangent plane of the vertex of the concave surface and the horizontal plane is greater than or equal to 0.5β - 15° and less than or equal to 0.5β + 10°.

[0016] Among them, the angle between the tangent plane of the vertex of the convex surface and the horizontal plane is β, and the angle γ between the tangent plane of the vertex of the concave surface and the horizontal plane is 0.5β.

[0017] Among them, the light-emitting component includes a light source, and the central light ray of the light source coincides with the optical axis of the light-transmitting component;

[0018] The distance a between the center point of the light source and the vertex of the convex surface is greater than or equal to 5 mm and less than or equal to 100 mm;

[0019] The distance b between the vertex of the convex surface and the vertex of the concave surface is greater than or equal to 4a and less than or equal to 30a.

[0020] Among them, the light source is a point light source;

[0021] Or, the light source is a surface light source, and the surface light source includes multiple light-emitting chips, and the distance between adjacent two light-emitting chips is less than a threshold value.

[0022] Among them, the light source is a surface light source, and the surface light source includes multiple light-emitting chips, and the distance between adjacent two light-emitting chips is less than or equal to 3 mm.

[0023] Among them, both the convex surface and the concave surface are spherical surfaces;

[0024] Or, at least one of the convex surface and the concave surface is an aspherical surface.

[0025] Among them, at least one of the convex surface and the concave surface is an aspherical surface, and the aspherical surface satisfies the following formula:

[0026]

[0027] Among them, z is the sagittal height at the point (x, y) on the aspherical surface, c x is the curvature in the x direction of the vertex of the aspherical surface, R x is the radius of curvature in the x direction of the vertex of the aspherical surface, c y is the curvature in the y direction of the vertex of the aspherical surface, R y is the radius of curvature in the y direction of the vertex of the aspherical surface, kx is the aspheric coefficient in the x direction, k y is the aspheric coefficient in the y direction, A 2n and B 2n are both aspheric high-order term coefficients or aspheric correction coefficients, and n is a positive integer greater than 1.

[0028] Among them, the concave surface is an aspheric surface, the radius of curvature R of the aspheric surface is greater than or equal to 0.1b and less than or equal to 40b, and the aspheric coefficient k of the aspheric surface is greater than or equal to -50 and less than or equal to 50.

[0029] Among them, the bottom surface is a plane;

[0030] Or, the bottom surface is an arc surface;

[0031] Or, the light-transmitting component includes a groove, the light-emitting component includes a light source and a substrate, the substrate is arranged at the opening of the groove, the substrate and the groove enclose a cavity, and the light source is arranged on the substrate and is located in the cavity.

[0032] Among them, the light-transmitting component further includes a first plane, the first plane is connected to the edge of the convex surface and surrounds the convex surface for one week, the bottom surface includes a central plane, a conical surface and a second plane, the conical surface surrounds the central plane for one week, and the second plane surrounds the conical surface for one week;

[0033] The light emitted by the light source enters the light-transmitting component through the central plane and the conical surface respectively.

[0034] Among them, the vertical distance between the central plane and the second plane is greater than the vertical distance between the first plane and the second plane.

[0035] Among them, a light-blocking layer is covered on the first plane, and the first plane is used to block light.

[0036] Among them, a coating is covered on the concave surface, and the coating is used for light reflection.

[0037] Among them, the thickness of the coating is greater than or equal to 100 nm and less than or equal to 150 nm.

[0038] Among them, the coating includes pure aluminum coating and / or vacuum coating.

[0039] Among them, the reflectivity of the concave surface is greater than or equal to 70%.

[0040] Among them, after the light passes through the refraction of the light-transmitting component, it is uniformly projected.

[0041] Among them, after the light passes through the reflection of the reflection component, it is collimated and projected.

[0042] On the other hand, the present invention also provides a 3D printer, including the light source component as described in any one of the above, and

[0043] A display screen for displaying a pattern with a specific contour;

[0044] A light source assembly is disposed on one side of the display screen. The light emitted by the light source assembly is evenly projected onto the display screen and passes through the display screen to cure the printing resin.

[0045] Wherein, the vertical distance c between the vertex of the concave surface of the reflection assembly and the surface of the display screen on the side opposite to the light source assembly is greater than or equal to 0.5b and less than or equal to 2b, where b is the distance between the vertex of the convex surface of the light-transmitting assembly and the vertex of the concave surface of the reflection assembly.

[0046] A light source assembly and a 3D printer proposed by the present invention mainly cooperate with each other through a light-transmitting assembly and a reflection assembly to homogenize and collimate light while reducing light loss, increasing light utilization rate, avoiding uneven projection light, and contributing to the uniform curing of the printing resin. In the prior art, since the light beam includes light rays with various angles, in order to ensure that the collimated light is as perpendicular to the display screen as possible, the stray light in the light is first filtered, and then the filtered light is collimated, resulting in some light being intercepted and unable to be projected, leading to a weakening of the projection light intensity and an inability to ensure the uniformity of the projection light, affecting the curing effect of the printing resin. Compared with the prior art, in the present application document, the light emitted by the light-emitting assembly is homogenized by the light-transmitting assembly and then projected onto the reflection assembly. The reflection assembly adjusts the angle of the light through reflection, making the range of the light propagation angle smaller, achieving light collimation, and collimating through reflection without causing light loss, ensuring the light intensity and uniformity of the transmitted light. Description of the Drawings

[0047] Figure 1 A schematic structural diagram of a light source assembly provided by an embodiment of the present invention;

[0048] Figure 2 A schematic diagram of the angle and position of the composition structure of a light source assembly provided by an embodiment of the present invention;

[0049] Figure 3 A three-dimensional structural diagram of a reflection assembly provided by an embodiment of the present invention;

[0050] Figure 4 For Figure 3 A side view in the x direction of the reflection assembly shown in

[0051] Figure 5 For Figure 3 A side view in the y direction of the reflection assembly shown in

[0052] Figure 6 For Figure 3 A top view in the z direction of the reflection assembly shown in

[0053] Figure 7 Schematic diagram of a light-emitting component and a light-transmitting component provided by an embodiment of the present invention;

[0054] Figure 8 Schematic diagram of another light-emitting component and a light-transmitting component provided by an embodiment of the present invention;

[0055] Figure 9 Schematic diagram of yet another light-emitting component and a light-transmitting component provided by an embodiment of the present invention. Detailed implementation manners

[0056] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation manners, structures, features, and effects of the light source component proposed according to the present invention. For ease of description, the light emitted by the light source component is described in the form of light rays.

[0057] On the one hand, as Figure 1-2 shown, an embodiment of the present invention provides a light source component for a 3D printer, including:

[0058] A light-emitting component 10, a light-transmitting component 20, and a reflection component 30;

[0059] The light-emitting component 10 and the reflection component 30 are arranged on opposite sides of the light-transmitting component 20;

[0060] The reflection component 30 cooperates with the light-transmitting component 20 to project the light emitted by the light-emitting component 10 after refraction by the light-transmitting component 20 and reflection by the reflection component 30.

[0061] In one implementation manner, the 3D printer includes a base box body. The base box body is a cavity structure. A display screen 40 is arranged on the base box body. The light source component is located inside the base box body. A material tank is arranged on the side of the display screen 40 opposite to the light source component. The sliced data of the printed model is transmitted to the display screen 40 one by one by the main controller. The display screen 40 allows light of a specific contour to pass through. The light emitted by the light source component is projected onto the display screen 40 and, after passing through the display screen 40, is projected onto the printing resin in the material tank in a specific contour, causing the printing resin to cure according to the specific contour. For ease of description, an example of a light projection method is taken where the display screen 40 is located at the top of the base box body and the light source component projects from bottom to top. In addition, the display screen 40 can also be located at the bottom of the base box body, and the light source component projects from top to bottom.

[0062] The light-emitting component 10 can be in various forms, such as a chip on board (COB) light source, an integrated light source, a laser light source, or a mercury lamp, etc. The light-emitting component 10 includes a light source 11 and a substrate 12. The light source 11 can be a point light source or a surface light source with a distance between light-emitting chips less than a threshold value. For example, if the threshold value is 3 mm, the above distance can refer to the distance from the edge of one light-emitting chip to the edge of another light-emitting chip. The light source 11 is an integrated light source or a COB light source with a distance between light-emitting chips less than or equal to 3 mm. In this embodiment, taking the light source 11 as a point light source or a surface light source with a very small distance between light-emitting chips as an example, such as the light-emitting component 20 emits light through UV lamp beads or multiple light-emitting chips with a very small distance. The light of the light-emitting component 10 propagates outward from the light-emitting chip in a conical beam. The light-transmitting component 20 is arranged on one side of the light propagation of the light-emitting component 10. After the light passes through the light-transmitting component 20, the refraction of the light will occur, causing the propagation angle of the light to change, such as making the light in the beam more uniform. After the light is refracted by the light-transmitting component 20, it is projected onto the reflecting component 30. The reflecting component 30 changes the light angle again through reflection, and then projects the light onto the display screen 40 in a collimated manner. It can be understood that the density of the light rays of the beam emitted by the light source 11 gradually decreases from the central beam to the outer light. The light spot formed on the projection plane will show that the light intensity gradually decreases from the center to the outside. To ensure the resin forming accuracy and the uniformity of curing, by refracting the light through the light-transmitting component 20, the propagation angle of the light is adjusted, such as making the light rays near the edge of the beam converge, and then adjusting the density of the light, so that the light propagates in a uniform beam shape after passing through the light-transmitting component 20. The reflecting component 30 is used for collimating the light, making the range of the propagation angles of the light rays in the beam smaller, so that the light rays propagate in almost the same direction, and then ensuring the collimation degree of the projected light. It should be noted that in this embodiment, since the refracted light is uniform light, and the reflecting component 30 has the function of collimating the light, the refracted light is directly projected onto the display screen 40 after being reflected by the reflecting component 30, which can ensure the uniformity and collimation degree of the projected light. There is no need to add a collimating lens or a filtering element between the reflecting component 30 and the display screen 40 for further processing of the light. The reflecting component 30 collimates the light by reflection. Compared with the method of using a collimating lens or a filtering element, it can achieve the effects of reducing the loss of light, ensuring the reasonable utilization of light, and ensuring the light intensity and uniformity of the transmitted light.

[0063] The light-transmitting component 20 and the reflecting component 30 can be adjusted according to different light source forms and projection accuracy requirements, aiming to make the light-transmitting component 20 and the reflecting component 30 cooperate with each other to adjust the light into a uniform light beam propagating in a nearly same direction. In one embodiment, the light-transmitting component 20 is a lens, and the point light source is located on the central optical axis of the lens. The central light ray of the light beam propagates along the optical axis, that is, the direction of the central light ray remains unchanged after passing through the light-transmitting component 20, while other light rays in the light beam will be refracted after passing through the light-transmitting component 20, adjusting the propagation path of the light to make the refracted light rays uniform. For convenience of description below, the geometric center point of the reflecting component 30 is used as the reflection point of the central light ray on the reflecting component 30. The light passing through the light-transmitting component 20 is called refracted light, and the light reflected by the reflecting component 30 is called reflected light. The reflected light is projected onto the display screen, and the reflected light also becomes projected light. In one embodiment, after passing through the light-transmitting component 20, the light beam still propagates in a beam shape. The reflection angles of the reflection points corresponding to different position light rays in the light beam on the reflecting component 30 can be adjusted to specifically adjust the angles of the reflected light rays. For example, the included angle between the reflected light ray of the large-angle light ray and the reflected light ray of the central light ray is made smaller, thereby realizing the collimation of the light. In another embodiment, the reflecting component 30 can be set such that the reflection angles gradually change from the geometric center point to each point outward. For example, the reflecting surface of the reflecting component 30 is an arc-shaped concave surface 31, and the arc-shaped concave surface 31 converges the transmitted light, making the beam-shaped transmitted light become collimated light.

[0064] In some embodiments, the main function of the light-transmitting component 20 is to refract light. During design, the reflection effect of the light-transmitting component 20 on light is reduced as much as possible.

[0065] A measuring instrument such as a radiometer is used to detect the irradiance of the display screen (40) or the projection area on the target surface, or to detect the light density or light intensity at multiple points on the display screen (40) or the target surface to determine whether the light is uniform. In some embodiments, after the light emitted by the light-emitting component 10 is refracted by the light-transmitting component 20, the irradiance detected in the projection area of the display screen (40) is the same or has only a slight difference, indicating that the light emitted by the light-emitting component 10 forms uniform light after being refracted by the light-transmitting component 20. By moving the relative position of the display screen (40) or the target surface and the reflecting component 3, whether the projection area changes can be detected to detect whether the light is collimated. In some embodiments, the light emitted by the light-emitting component 10 is refracted by the light-transmitting component 20 and then projected onto the reflecting component 30. The reflecting component 30 reflects the light projected onto the reflecting surface and then projects it onto the display screen (40). When the display screen (40) is moved, if the projection contour and area are stable or change slightly, it can be known that the light forms collimated light after being reflected by the reflecting component 30 and is collimated and projected onto the display screen (40).

[0066] The slight difference in the above irradiance and the slight changes in the projected contour and area may be caused by lens processing errors or the external environment. It is understandable that most of the light projected onto the display screen 40 in this application is uniform and vertical light, and the light utilization rate is greatly increased, and there will be no large-scale light loss.

[0067] A light source assembly and a 3D printer proposed in an embodiment of the present invention mainly cooperate with a light-transmitting component and a reflecting component to equalize and collimate light while reducing light loss, increasing light utilization rate, avoiding uneven projected light, and contributing to the uniform curing of printing resin. In the prior art, since the light beam includes light rays of various angles, in order to ensure that the collimated light is as collimated as possible with the display screen, a filter such as some light-shielding plates filters the stray light in the light, resulting in a weakened projected light intensity and an inability to ensure the uniformity of the projected light, affecting the curing effect of the printing resin. Compared with the prior art, in this application document, the light emitted by the light-emitting component is projected onto the reflecting component after being equalized by the light-transmitting component, and the reflecting component adjusts the angle of the light by reflecting the light, making the range of the light propagation angle smaller, realizing the collimation of the light, and collimating by reflection without causing light loss, ensuring the light intensity and uniformity of the transmitted light.

[0068] In this application, the light-transmitting component 20 and the reflecting component 30 can have various forms, and the optimal combination can be obtained through experiments. For example, changing the structure of the reflecting surface of the reflecting component 30 and adjusting the setting direction of the reflecting component 30 will produce different reflection effects, that is, different collimation effects. This application provides several specific structures and specific parameters of the light-transmitting component 20 and the reflecting component 30 for the specific form and setting position of the point light source in this embodiment.

[0069] The light-transmitting component 20 includes a convex surface 21 and a bottom surface 22 facing away from each other, the reflecting component 30 includes a concave surface 31, the light-emitting component 10 is correspondingly arranged with the bottom surface 22, and the concave surface 31 is correspondingly arranged with the convex surface 21. The light is refracted through the convex surface 21 and the bottom surface 22, and the light is reflected through the concave surface 31.

[0070] In one embodiment, such as Figure 3-6As shown, the reflection component 30 is an approximately plate-like structure, with one side being a plane and the other side being a concave surface 31. The concave surface 31 is the reflection surface of the reflection component 30. The concave surface 31 can be a spherical surface or an aspherical surface. The reflection component 30 is inclined, and the concave surface 31 faces the display screen 40 and the light-transmitting component 20. Taking the light-transmitting component 20 as a plano-convex lens, that is, its bottom surface 22 is a plane, the plano-convex lens is located obliquely above the reflection component 30. The plano-convex lens is inclined, the convex surface 21 of the plano-convex lens corresponds to the concave surface 31 of the reflection component 30, the light-emitting component 10 corresponds to the plane of the plano-convex lens, and the light-emitting point of the light-emitting component 10 corresponds to the optical axis of the plano-convex lens. The light forms a uniform light beam with a relatively small divergence angle after passing through the refraction of the plano-convex lens, and then is reflected by the reflection component 30 to converge the light beam to form collimated light.

[0071] In one implementation, as Figure 2 shown, the angle β between the tangent plane of the vertex of the convex surface 21 and the horizontal plane is greater than or equal to 30° and less than 45°, such as 30°, 33°, 40°, 44°, etc.; or, the angle β between the tangent plane of the vertex of the convex surface 21 and the horizontal plane is greater than 45° and less than 90°, such as 48°, 55°, 60°, 75°, 84°, 89°, etc.; or, the angle β between the tangent plane of the vertex of the convex surface 21 and the horizontal plane is equal to 45°.

[0072] The vertex of the convex surface 21 can be understood as the geometric center point of the convex surface 21, and the vertex of the concave surface 31 can be understood as the geometric center point of the concave surface 31, that is, the center of the reflection surface of the reflection component 30. Taking the light-transmitting component 20 as a plano-convex lens as an example, the vertex of the convex surface 21 is the intersection point of the optical axis of the plano-convex lens and the convex surface 21. In one embodiment, the angle β is greater than or equal to 30° and less than 45°, ensuring that the light passing through the light-transmitting component 20 propagates as much as possible obliquely downward to avoid interference of the light from the light-emitting component 10 and the light-transmitting component 20 on the display screen 40. In another implementation, the angle β is greater than 45° and less than or equal to 90°, enabling the light-emitting component 10 and the light-transmitting component 20 to be located outside the light between the reflection component 30 and the display screen 40, avoiding the influence of the light-emitting component 10 and the light-transmitting component 20 on the reflected light, and the light-emitting component 10 and the light-transmitting component 20 can be as close as possible to the bottom of the 3D printer to avoid the large amount of heat generated by the light-emitting component 10 and the light-transmitting component 20 from interfering with the display screen.

[0073] In one embodiment, the angle γ between the tangent plane of the vertex of the concave surface 31 and the horizontal plane is greater than or equal to 0.5β - 15° and less than or equal to 0.5β + 10°, such as 0.5β - 15°, 5β - 10°, 0.5β - 5°, 0.5β, 0.5β + 5°, 0.5β + 10°, etc. Ensure that the angle between the tangent plane of the vertex of the convex surface 21 and the tangent plane of the vertex of the concave surface 31 is within a certain range, avoiding excessive angles that would increase the difficulty of fitting and the processing difficulty of the concave surface 31 or the convex surface 21. For example, when both the concave surface 31 and the convex surface 21 are aspherical surfaces, an excessive angle will result in a complex curved surface structure. The above ranges of the angle β and the angle γ also ensure better fitting between the light-transmitting component 20 and the reflecting component 30, achieving the best collimation effect.

[0074] In other embodiments, the angle β can also be 45°, and the angle γ between the tangent plane of the vertex of the concave surface 31 and the horizontal plane is γ = 0.5β.

[0075] The display screen 40 is horizontally arranged. The angle β between the tangent plane of the vertex of the convex surface 21 and the horizontal plane is 45°, and the angle γ between the tangent plane of the vertex of the concave surface 31 and the horizontal plane is 22.5°. The central ray of the light beam propagates in the same direction after passing through the plano-convex lens, that is, the central ray propagates at an angle of 45° with the horizontal plane. The incident point of the central ray on the reflecting component 30 is the vertex of the concave surface 31, that is, the incident angle of the central ray is 22.5°. That is, after the central ray is reflected, the angle will be deflected by 45°, and the central ray becomes a vertical ray projected onto the display screen 40. The angle between the tangent plane of each point on the concave surface 31 and the horizontal plane gradually changes from the vertex outwards. Structurally, it is gradually bent upwards from the vertex to form an arc surface. For example, the angle between the intermediate ray located between the central ray and the marginal ray in the light beam and the horizontal plane when it exits from the point light source is 30°. After being refracted by the light-transmitting component 20, the refracted light forms an angle of 40° with the horizontal plane. The reflection point of the light ray on the reflecting component 30 is different from the vertex, and the angle between the tangent plane of the reflection point and the horizontal plane is 25°. The incident angle of the intermediate ray is 25°. That is, after the intermediate ray is reflected, the angle will be deflected by 50°, and the intermediate ray changes from an angle of 40° with the horizontal plane to a vertical ray projected onto the display screen 40.

[0076] It can be understood that it is not necessary to set the angle between the tangent plane of each point on the concave surface 31 and the horizontal plane one by one. For example, when the concave surface 31 is an aspherical surface, by adjusting the aspherical parameters, such as the radius of curvature R or the aspherical coefficient of the aspherical surface, the collimation of the concave surface 31 for light can be achieved such that most of the light rays are collimated or projected onto the display screen 40 with a small angular deviation.

[0077] In one embodiment, such as Figure 2As shown, the light-emitting component 10 includes a light source 11. The light source 11 can be a point light source or the above-mentioned surface light source. The central ray of the light source 11 coincides with the optical axis of the light-transmitting component 20. The distance a between the center point of the light source 11 and the vertex of the convex surface 21 is greater than or equal to 5 mm and less than or equal to 100 mm, such as 5 mm, 15 mm, 30 mm, 50 mm, 80 mm, 100 mm, etc. The distance b between the vertex of the convex surface 21 and the vertex of the concave surface 31 is greater than or equal to 4a and less than or equal to 30a, such as 4a, 6a, 15a, 20a, 30a, etc.

[0078] When the light source 11 is a point light source, the central ray of the above-mentioned light source 11 is the central ray of the light beam emitted by the point light source, and the center point of the above-mentioned light source 11 is the point light source; when the light source 11 is a surface light source, the central ray of the above-mentioned light source 11 is the central ray of the light beam emitted by the whole surface light source, or it can be understood as the central ray of the light beam emitted by the center point on the surface light source. The center point of the above-mentioned light source 11 is the central light-emitting point on the surface light source. In some embodiments, since the light source 11 has a thickness, the center point of the light source 11 can refer to the center point at the top of the light source 11, that is, the center point of the end face of the light source 11 close to the light-transmitting component 20. For example, the central light-emitting point of the surface light source close to the vertex of the light-transmitting component 20 is used as the center point of the light source 11. Taking the light-transmitting component 20 as a plano-convex lens and the light source 11 as a UV lamp bead as an example, the center of the UV lamp bead is arranged opposite to the optical center of the plano-convex lens. The distance a is the sum of the central thickness of the plano-convex lens and the distance from the center point of the top surface of the UV lamp bead close to the light-transmitting component 20 to the center point of the plane of the plano-convex lens. The distance a is greater than or equal to 5 mm to ensure that there is enough distance between the UV lamp bead and the plane of the plano-convex lens, so that the UV lamp bead is close to the focal point of the plano-convex lens, and to ensure that the plano-convex lens has enough thickness, thereby ensuring effective refraction of light; the distance a is less than or equal to 100 mm to avoid excessive weakening of the light intensity due to too long propagation distance of light in the plano-convex lens. The distance b is greater than or equal to 4a to avoid mutual interference between the reflected light and the light of the light source component 10. The distance b is less than or equal to 30a to avoid excessive weakening of the light intensity due to too long propagation distance of light and to reduce the space occupied by the light source component.

[0079] In some embodiments, both the convex surface 21 and the concave surface 31 can be spherical surfaces, or at least one of the convex surface 21 and the concave surface 31 is an aspherical surface. An aspherical surface refers to an arc surface with inconsistent curvatures everywhere. The curvature from the vertex to the edge of the aspherical surface changes continuously. The surface shape of the aspherical surface can be represented by a high-order polynomial containing aspherical coefficients. The aspherical surface can be a rotationally symmetric structure specifically. In some embodiments, the surface shape of the aspherical surface is represented by the following polynomial:

[0080]

[0081] where z is the sag height at the point (x, y) on the aspherical surface, c xis the curvature in the x - direction of the aspherical vertex, R x is the radius of curvature in the x - direction of the aspherical vertex, c y is the curvature in the y - direction of the aspherical vertex, R y is the radius of curvature in the y - direction of the aspherical vertex, k x is the aspherical coefficient in the x - direction, k y is the aspherical coefficient in the y - direction, A 2n and B 2n are both high - order aspherical coefficients or aspherical correction coefficients. The absolute value ranges of A2n and B2n are 0 ≤ A2n < 1, 0 ≤ B2n < 1, where n is a positive integer greater than 1, such as n = 2, 3, 4..., and the specific parameters are adjusted according to the corresponding scenarios for their accurate values, which will not be elaborated here.

[0082] The aspherical surface shape can be adjusted by adjusting the radius of curvature R in the x - direction of the above - mentioned aspherical vertex x and the radius of curvature R in the y - direction of the aspherical vertex y and the aspherical coefficient k in the x - direction x and the aspherical coefficient k in the y - direction y to adjust the aspherical surface shape, and further achieve the effect of adjusting the light uniformity and collimation.

[0083] Among them, the radius of curvature is used to describe the degree of curvature of the curved surface. It can be approximately understood that the larger the radius of curvature, the smaller the degree of curvature of the curved surface. The radius of curvature of the aspherical vertex is the main parameter determining the imaging of the aspherical optical system, affecting the basic properties of the aspherical surface, such as the focal length of the aspherical surface. By adjusting the radius of curvature of the aspherical vertex, the aspherical surface can achieve the best optical effect. In one implementation, the concave surface 31 is an aspherical surface, and the radius of curvature R x and the radius of curvature R y both satisfy being greater than or equal to 0.1b and less than or equal to 40b (such as 0.1b, 5b, 10b, 30b, 40b, etc.), so that the distance between the focus and the vertex of the concave surface 31 is appropriate, ensuring that the vertex of the refracted light emitted by the light - transmitting component 20 is close to or coincides with the focus of the concave surface 31, and ensuring the effective collimation of the refracted light by the concave surface 31. Among them, the vertex of the refracted light is obtained by extending the refracted light in the reverse direction of the light propagation direction, and the focus of the extended lines of all refracted lights is the vertex of the refracted light. It can be understood that the vertex of the refracted light is a virtual point, not an actual light - emitting point.

[0084] Among them, the aspherical coefficient can also be called the conic constant or the conic - section coefficient. In some implementations, the aspherical coefficient k = -e 2 , where e is the eccentricity. When k x = k y = 0, the arc surface is a spherical surface, k x and k yWhen gradually decreasing from 0, the surface shape of the curved surface will gradually approach a plane and become an approximately flat ellipsoidal surface, k x and k y When gradually increasing from 0, the edge of the arc surface gradually curls inward. It can be approximately understood that the aspheric coefficient affects the degree of curvature of the curved surface, k x and k y When gradually decreasing from 0, it is approximately that the radius of curvature gradually increases, k x and k y When gradually increasing from 0, it is approximately that the radius of curvature gradually decreases. In this embodiment, the aspheric coefficient k x in the x direction and the aspheric coefficient k y in the y direction both satisfy being greater than or equal to -50, so that the concave surface has a sufficient effect of converging the light beam and can effectively collimate the light beam. The aspheric coefficient k x in the x direction and the aspheric coefficient k y in the y direction both satisfy being less than or equal to 50, so that the aperture of the reflection component 30 will not be too small, the extension range of the reflection surface is sufficient, ensuring that the reflected light corresponding to any point light source has a sufficient projection area, and the aspheric coefficient k x in the x direction and the aspheric coefficient k y in the y direction both satisfy being greater than or equal to -50 and less than or equal to 50 (such as -50, -20, 0, 20, 40, 50, etc.), which also makes the sizes of the reflection component 30 and the light-transmitting component 20 appropriate, convenient for processing, and ensuring that the light source component can be conveniently arranged in the base box without occupying too much space.

[0085] The structure of the light-transmitting component 20 can be various, and the positions of the light-transmitting component 20 and the light-emitting component 10 can also have various setting methods according to the different structures of the light-transmitting component 20. In this embodiment, three specific structures are exemplified, and the light-transmitting component 20 is not limited to the following structures:

[0086] First, as shown in Figure 7 , the bottom surface 22 is a plane, that is, the light-transmitting component 20 includes a plane and an arc surface facing away from each other. The light-transmitting component 20 can specifically be a plano-convex lens. The light-emitting point of the light-emitting component 10 can correspond to the center of the bottom surface 22 of the light-transmitting component 20, that is, corresponding to the optical center of the plano-convex lens.

[0087] Second, as shown in Figure 8 , the bottom surface 22 is an arc surface. The bottom surface 22 can be a spherical surface or an aspherical surface. By adjusting the surface shape of the bottom surface 22 to cooperate with the convex surface 21, the flexible adjustment of the light refraction effect of the light-transmitting component 20 can be realized, and it can be obtained by further processing an existing plano-convex lens, reducing the production cost. The bottom surface 22 can be an arc surface concave toward the convex surface 21 side, that is, the light-transmitting component 20 is a concave-convex lens, or the bottom surface 22 can be an arc surface convex toward the side opposite to the convex surface 21, that is, the light-transmitting component 20 is a biconvex lens.

[0088] Thirdly, as Figure 9 shown, the light-transmitting component 20 includes a groove 23, the light-emitting component 10 includes a light source 11 and a substrate 12. The substrate 12 is disposed at the opening of the groove 23. The substrate 12 and the groove 23 enclose a cavity. The light source 11 is disposed on the substrate 12 and is located inside the cavity.

[0089] Since the position of the light source 11 is relatively close to the display screen 40 and the light intensity is the strongest, setting the light source 11 inside the cavity enables the light of the light source 11 not to affect the display screen 40, and the light beam of the light source 11 is not easily affected by the external environment.

[0090] In one embodiment, as Figure 9 shown, the light-transmitting component 20 further includes a first plane 24. The first plane 24 is connected to the edge of the convex surface 21 and surrounds the convex surface 21 for one week. The bottom surface 22 includes a central plane 231, a conical surface 232, and a second plane 25. The conical surface 232 surrounds the central plane 231 for one week, and the second plane 25 surrounds the conical surface 232 for one week. In some embodiments, the central plane 231 is closer to the convex surface 21 than the conical surface 232. The light emitted by the light source 11 enters the light-transmitting component 20 through the central plane 231 and the conical surface 232 respectively.

[0091] Taking Figure 9 the direction in which the opening of the groove 23 in the above is vertically downward as an example, the light-transmitting component 20 between the convex surface 21 and the groove 23 is a solid transparent region. A ring-shaped convex platform is provided on the outer periphery of the lens region. The top surface of the ring-shaped convex platform is the above-mentioned first plane 24, and the second plane 25 on the outer periphery of the opening of the groove 23 is the bottom surface of the ring-shaped convex platform. The ring-shaped convex platform is used to connect to a fixing device to fix the light-transmitting component 20 and to connect to the substrate 12. In addition to the connecting function, the first plane 24 also has the function of filtering stray light. For example, if a light-blocking layer is covered on the first plane 24, the first plane 24 is also used to block part of the large-angle light. When the light beam of the light source 11 is relatively divergent and includes large-angle stray light, the stray light will be guided to the first plane 24 after entering the light-transmitting component 20. By setting a light-blocking layer on the first plane 24, such as a plastic sheet or a metal sheet, etc., to block the stray light and avoid the stray light from affecting the uniformity and collimation of the light beam. And since the first plane 24 is lower than the bottom of the groove 23, and the bottom of the groove is the above-mentioned central plane 231, most of the light can still pass through the light-transmitting component 20 to become refracted light, without causing the light intensity to decrease. The conical surface 232 is inclined relative to the central light, and has a stronger light-converging effect on the light entering the light-transmitting component 20 through the conical surface 232, so that the light near the edge of the light beam is densified, making the light uniform. When applied to a light-curing printer, it can optimize the intensity and uniformity of the light at the edge of the display screen.

[0092] In one implementation, the perpendicular distance between the central plane 231 and the second plane 25 is greater than the perpendicular distance between the first plane 24 and the second plane 25. Taking the Figure 9 direction as an example, the central plane 231 is higher than the first plane 24, reducing the occlusion of the refracted light by the boss, enabling the light-transmitting component 20 to have a larger area for light adjustment, allowing a large amount of light to pass through the area between the conical surface 232 and the convex surface 21 and project onto the display screen 40, ensuring the uniform adjustment of light by the lens and the light intensity.

[0093] The light-transmitting component 20 is preferably a plano-concave lens. The processing technology of the plano-concave lens is simple and the cost is low. The plano-concave lens can be specifically processed from plastic materials such as PMMA and PC, or from glass materials such as borosilicate glass, quartz glass, H-K9, and H-K51.

[0094] The reflection component 30 can be processed from metal materials such as aluminum alloy and stainless steel. The reflection component 30 can also be processed from plastic materials such as PMMA and PC. Or, the reflection component 30 can also be processed from glass materials such as borosilicate glass, quartz glass, H-K9, and H-K51. The reflection surface can be processed using the reflection function of the metal material itself. Or, a coating is covered on the reflection surface. The coating includes metal coatings such as aluminum and silver coatings or other alloy material coatings, such as pure aluminum coatings and / or vacuum coatings. The coating can enhance the reflectivity, such as the reflectivity being greater than or equal to 70%, ensuring the light intensity of the projected light. In this implementation, the reflectivity is 90%, achieving the reduction of light loss and ensuring the light intensity.

[0095] In some implementations, the coating thickness is greater than or equal to 100 nm to ensure the reflection performance of the coating and it is not easy to fall off. The coating thickness is less than or equal to 150 nm to avoid the change range of the thickness when the coating is heated, ensuring the stability of the optical path distance between the light-transmitting component 20 and the concave surface of the reflection component 30, and between the concave surface of the reflection component 30 and the display screen 40, and avoiding the influence on the projected light caused by the thermal expansion of the coating. In one implementation, the coating thickness is 120 nm.

[0096] On the other hand, the embodiment of the present invention also provides a 3D printer, including the light source component as described in any one of the above, and

[0097] a display screen 40 for displaying a pattern with a specific contour;

[0098] The light source component is arranged on one side of the display screen 40, and the light emitted by the light source component is uniformly projected onto the display screen 40 and passes through the display screen 40 to cure the printing resin.

[0099] The 3D printer further includes a base box body, a lifting component, a printing platform and a material tank. The material tank is used for containing printing resin and is placed on the display screen 40. The light source component is located inside the base box body, and the lifting component connects the base box body and the printing platform. The display screen 40 is connected to the main controller of the 3D printer. The main controller analyzes and divides the printing data into patterns one by one. Each pattern can correspond to the shape of each layer of the printing model. The main controller transmits the patterns to the display screen 40. The projection light of the light source component is projected onto the display screen 40. The display screen 40 allows the projection light of a specific contour to pass through and be projected onto the printing resin according to the patterns, so that the printing resin is cured to form a model layer with the same pattern shape. The printing platform drives the model to move up or down to separate the model from the material tank, and then the above process is repeated to realize layer-by-layer printing of the model.

[0100] The setting position of the light source component has a direct impact on the light intensity and light quality of the transmitted light. In this embodiment, the distance a between the point light source 12 and the vertex of the convex surface 21 is greater than or equal to 5 mm and less than or equal to 100 mm. The distance b between the vertex of the convex surface 21 and the vertex of the concave surface 31 is greater than or equal to 4a and less than or equal to 30a. The vertical distance c between the vertex of the concave surface 31 of the reflection component 30 and the surface of the display screen on the side opposite to the light source component is greater than or equal to 0.5b and less than or equal to 2b. The above distances a, distance b and vertical distance c are sequentially interrelated, so that the position of the reflection component 30 is restricted by the relative positions of the point light source 12 and the light transmissive component 20. The distance c being greater than or equal to 0.5b ensures that the projection light is not affected by the light of the point light source 12 and leaves enough space for the light transmissive component 20. The distance c being less than or equal to 2b can ensure a relatively high light intensity, thereby achieving an optimal projection effect.

[0101] It can be understood that the above-listed distance ranges (parameters) do not exist independently, but rather restrict each other to jointly achieve the adjustment of the light propagation angle, so that the refracted light exhibits good uniformity and collimation. The above light source component is a complex and organic optical system. The realization of the uniformity and collimation functions is obtained by the mutual restriction of multiple parameters. The range of parameters is not obtained by testing a single parameter, but by cross-testing the value ranges of multiple parameters. For example, when the distance a takes a value of 5 mm, the distance between the vertex of the convex surface 21 and the vertex of the concave surface 31 is tested multiple times to obtain the optimal distance range. Then, when the distance a takes a value of 6 mm, the distance between the vertex of the convex surface 21 and the vertex of the concave surface 31 is also tested multiple times. This cycle is repeated until multiple sets of range data of the distance between the vertex of the convex surface 21 and the vertex of the concave surface 31 corresponding to different values of a are obtained. Then, the law of the range data is summarized to obtain a range value with a certain universality, that is, the distance b between the vertex of the convex surface 21 and the vertex of the concave surface 31 is greater than or equal to 4a and less than or equal to 30a. Within this value range, a better homogenization and collimation effect can be achieved, thus playing a guiding role. Similarly, for the value ranges of angles such as the angle β between the tangent plane of the vertex of the convex surface and the horizontal plane and the angle γ between the tangent plane of the vertex of the concave surface and the horizontal plane and their mutual restriction relationships, multiple combinations are used for sequential experiments. Finally, a restriction relationship such as the angle γ is greater than or equal to 0.5β - 15° and less than or equal to 0.5β + 10° is obtained.

[0102] On the one hand, an embodiment of the present invention provides

[0103] 1. A light source component for a 3D printer, comprising:

[0104] A light-emitting component 10, a light-transmitting component 20, and a reflecting component 30;

[0105] The light-emitting component 10 and the reflecting component 30 are arranged on opposite sides of the light-transmitting component 20;

[0106] The reflecting component 30 cooperates with the light-transmitting component 20 to project the light emitted by the light-emitting component 10 after passing through the refraction of the light-transmitting component 20 and the reflection of the reflecting component 30.

[0107] 2. The light source component according to 1, wherein the light-transmitting component 20 includes a convex surface 21 and a bottom surface 22 on opposite sides, the reflecting component 30 includes a concave surface 31, the light-emitting component 10 is correspondingly arranged with the bottom surface 22, and the concave surface 31 is correspondingly arranged with the convex surface 21;

[0108] The light passes through the refraction of the convex surface 21 and the bottom surface 22, and the light passes through the reflection of the concave surface 31.

[0109] 3. The light source component according to 2, wherein the angle β between the tangent plane of the vertex of the convex surface 21 and the horizontal plane is greater than or equal to 30° and less than 45°;

[0110] Alternatively, the angle β between the tangent plane of the vertex of the convex surface 21 and the horizontal plane is greater than 45° and less than or equal to 90°;

[0111] Alternatively, the angle β between the tangent plane of the vertex of the convex surface 21 and the horizontal plane is equal to 45°.

[0112] 4. For the light source assembly according to 2, the angle between the tangent plane of the vertex of the convex surface 21 and the horizontal plane is β, and the angle γ between the tangent plane of the vertex of the concave surface 31 and the horizontal plane is greater than or equal to 0.5β - 15° and less than or equal to 0.5β + 10°.

[0113] 5. For the light source assembly according to 2, the angle between the tangent plane of the vertex of the convex surface 21 and the horizontal plane is β, and the angle γ between the tangent plane of the vertex of the concave surface 31 and the horizontal plane is γ = 0.5β.

[0114] 6. For the light source assembly according to 2, the light emitting assembly 10 includes a light source 11, and the central ray of the light source 11 coincides with the optical axis of the light transmissive assembly 20;

[0115] The distance a between the center point of the light source 11 and the vertex of the convex surface 21 is greater than or equal to 5 mm and less than or equal to 100 mm;

[0116] The distance b between the vertex of the convex surface 21 and the vertex of the concave surface 31 is greater than or equal to 4a and less than or equal to 30a.

[0117] 7. For the light source assembly according to 6, the light source 11 is a point light source;

[0118] Alternatively, the light source 11 is a surface light source, and the surface light source includes a plurality of light emitting chips, and the distance between adjacent two light emitting chips is less than a threshold value.

[0119] 8. For the light source assembly according to 6, the light source 11 is a surface light source, and the surface light source includes a plurality of light emitting chips, and the distance between adjacent two light emitting chips is less than or equal to 3 mm.

[0120] 9. For the light source assembly according to 2, both the convex surface 21 and the concave surface 31 are spherical surfaces;

[0121] Alternatively, at least one of the convex surface 21 and the concave surface 31 is an aspherical surface.

[0122] 10. For the light source assembly according to 2,

[0123] At least one of the convex surface and the concave surface is an aspherical surface, and the aspherical surface satisfies the following formula:

[0124]

[0125] where z is the sag height at the point (x, y) on the aspherical surface, c xis the curvature in the x - direction of the aspherical vertex, R x is the radius of curvature in the x - direction of the aspherical vertex, c y is the curvature in the y - direction of the aspherical vertex, R y is the radius of curvature in the y - direction of the aspherical vertex, k x is the aspherical coefficient in the x - direction, k y is the aspherical coefficient in the y - direction, A 2n and B 2n are both high - order aspherical coefficients or aspherical correction coefficients, and n is a positive integer greater than 1.

[0126] 11. According to the light source component described in 2, the concave surface 31 is aspherical, the radius of curvature R of the aspherical surface is greater than or equal to 0.1b and less than or equal to 40b, and the aspherical coefficient k of the aspherical surface is greater than or equal to - 50 and less than or equal to 50.

[0127] 12. According to the light source component described in 2, the bottom surface 22 is a plane;

[0128] Or, the bottom surface 22 is an arc surface;

[0129] Or, the light - transmitting component 20 includes a groove 23, the light - emitting component 10 includes a light source 11 and a substrate 12, the substrate 12 is arranged at the opening of the groove 23, the substrate 12 and the groove 23 enclose a cavity, and the light source 11 is arranged on the substrate 12 and is located inside the cavity.

[0130] 13. According to the light source component described in 2, the light - transmitting component 20 further includes a first plane 24, the first plane 24 is connected to the edge of the convex surface 21 and surrounds the convex surface 21 for one week, the bottom surface 22 includes a central plane 231, a conical surface 232 and a second plane 25. The conical surface 232 surrounds the central plane 231 for one week, and the second plane 25 surrounds the conical surface 232 for one week;

[0131] The light emitted by the light source 11 enters the light - transmitting component 20 through the central plane 231 and the conical surface 232 respectively.

[0132] 14. According to the light source component described in 13, the vertical distance between the central plane 231 and the second plane 25 is greater than the vertical distance between the first plane 24 and the second plane 25.

[0133] 15. According to the light source component described in 13, the first plane 24 is covered with a light - blocking layer, and the first plane 24 is used to block light.

[0134] 16. According to the light source component described in 2, the concave surface 31 is covered with a coating, and the coating is used for light reflection.

[0135] 17. According to the light source component described in 16, the thickness of the coating is greater than or equal to 100nm and less than or equal to 150nm.

[0136] 18. The light source assembly according to claim 16, wherein the coating includes pure aluminum coating and / or vacuum coating.

[0137] 19. The light source assembly according to claim 16, wherein the reflectivity of the concave surface 31 is greater than or equal to 70%.

[0138] 20. The light source assembly according to claim 1, characterized in that

[0139] After the light passes through the refraction of the light-transmitting component, it is uniformly projected.

[0140] 21. The light source assembly according to claim 1, characterized in that

[0141] After the light passes through the reflection of the reflection component, it is collimated and projected.

[0142] On the other hand, the embodiments of the present invention also provide

[0143] 22. A 3D printer, comprising a light source assembly as described in any one of the above, and

[0144] a display screen 40, the display screen 40 is used to display a pattern of a specific contour;

[0145] The light source assembly is arranged on one side of the display screen 40, and the light emitted by the light source assembly is uniformly projected onto the display screen 40 and passes through the display screen 40 to cure the printing resin.

[0146] 23. The 3D printer according to claim 22, wherein the vertical distance c between the vertex of the concave surface 31 of the reflection component 30 and the surface of the display screen 40 on the side opposite to the light source assembly is greater than or equal to 0.5b and less than or equal to 2b, where b is the distance between the vertex of the convex surface 21 of the light-transmitting component 20 and the vertex of the concave surface 31 of the reflection component 30.

[0147] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, and all should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A light source assembly for a 3D printer, characterized in that, Comprising: a light-emitting component, a light-transmitting component, and a reflecting component; the light-emitting component and the reflecting component are disposed on opposite sides of the light-transmitting component; the reflecting component cooperates with the light-transmitting component to project the light emitted by the light-emitting component after refraction by the light-transmitting component and reflection by the reflecting component.

2. The light source assembly according to claim 1, wherein the light-transmitting component includes a convex surface and a bottom surface opposite to each other, the reflecting component includes a concave surface, the light-emitting component is disposed corresponding to the bottom surface, and the concave surface is disposed corresponding to the convex surface; the light is refracted by the convex surface and the bottom surface, and the light is reflected by the concave surface.

3. The light source assembly according to claim 2, wherein the angle β between the tangent plane of the vertex of the convex surface and the horizontal plane is greater than or equal to 30° and less than 45°; alternatively, the angle β between the tangent plane of the vertex of the convex surface and the horizontal plane is greater than 45° and less than 90°; alternatively, the angle β between the tangent plane of the vertex of the convex surface and the horizontal plane is equal to 45°.

4. The light source assembly according to claim 2, wherein the angle between the tangent plane of the vertex of the convex surface and the horizontal plane is β, and the angle γ between the tangent plane of the vertex of the concave surface and the horizontal plane is greater than or equal to 0.5β - 15° and less than or equal to 0.5β + 10°.

5. The light source assembly according to claim 2, wherein the angle between the tangent plane of the vertex of the convex surface and the horizontal plane is β, and the angle γ between the tangent plane of the vertex of the concave surface and the horizontal plane is 0.5β.

6. The light source assembly according to claim 2, wherein the light-emitting component includes a light source, and the central light ray of the light source coincides with the optical axis of the light-transmitting component; the distance a between the center point of the light source and the vertex of the convex surface is greater than or equal to 5 mm and less than or equal to 100 mm; the distance b between the vertex of the convex surface and the vertex of the concave surface is greater than or equal to 4a and less than or equal to 30a.

7. The light source assembly according to claim 6, wherein the light source is a point light source; alternatively, the light source is a surface light source, and the surface light source includes a plurality of light-emitting chips, and the distance between adjacent two of the light-emitting chips is less than or equal to a threshold value.

8. The light source assembly according to claim 6, wherein the light source is a surface light source, and the surface light source includes a plurality of light-emitting chips, and the distance between adjacent two of the light-emitting chips is less than or equal to 3 mm.

9. A 3D printer, characterized in that, Comprising the light source assembly according to any one of claims 1 - 8 above, and a display screen for displaying a pattern of a specific contour; the light source assembly is disposed on one side of the display screen, and the light emitted by the light source assembly is uniformly projected onto the display screen and passes through the display screen to cure printing resin.

10. The 3D printer according to claim 9, wherein the perpendicular distance c between the vertex of the concave surface of the reflecting component and the surface of the display screen on the side opposite to the light source assembly is greater than or equal to 0.5b and less than or equal to 2b, where b is the distance between the vertex of the convex surface of the light-transmitting component and the vertex of the concave surface of the reflecting component.

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