A 3D printing projection system based on DLP technology

Abstract

This application discloses a 3D printing projection system based on DLP technology. By sequentially arranging a DMD, a protective glass cover, a galvanometer, an equivalent prism, and an objective lens along the optical axis, the requirements for the galvanometer's aperture are reduced. At the same time, by limiting the coordinates of each vertex within the rectangular boundary range of the galvanometer's aperture, a minimum boundary range of the limited galvanometer's aperture is obtained. This allows incident light from the DMD in any state to completely pass through the galvanometer, thereby preventing damage to the circuit structure outside the galvanometer's glass. This allows the galvanometer to maintain a relatively stable and long operating life while achieving a high resolution.

Description

Technical Field

[0001] The present application relates to the technical field of optical projection equipment, and in particular to a 3D printing projection system based on DLP technology. Background Art

[0002] As technology matures, projection equipment is being used in more and more fields, such as home audio and video, advertising projection, industrial projection testing, etc. In particular, the demand for small-sized, high-brightness, and high-resolution projection machines is becoming increasingly strong.

[0003] Compared with 3D printing systems based on LCoS devices, micro-projections based on DLP technology have huge advantages in lifespan. Compared with consumer-grade micro-projection systems, micro-projection systems used in 3D printing systems need to achieve clear imaging, less distortion, more uniform light field distribution, and longer service life of the objective lens at a closer working distance.

[0004] However, compared with 3D printing systems based on LCoS devices, 3D printing systems based on DLP technology have certain disadvantages in intrinsic resolution. The physical pixel of the digital micromirror DMD is 5.4um. At the same time, for economic benefits, the size of the digital micromirror DMD is generally not larger than 0.47 inches. Therefore, the actual physical resolution of the 3D printing system based on DLP technology will not be able to achieve the effect of 1080P, which requires it to be matched with a galvanometer to achieve an increase in resolution.

[0005] like Figure 1 As shown, after the light passes through the illumination system and DMD1, it enters the objective lens system. During this light propagation process, it needs to pass through the glass protection cover 2, the equivalent prism 3, the galvanometer 4 and the air gap between the above optical components in sequence before entering the objective lens 5. Among them, the divergence half angle of the light path entering the objective lens is generally 17 degrees.

[0006] Under the current working environment, the isotropic aperture size of the light path entering the galvanometer 4 is related to the divergence angle of the light path from DMD1, the size of DMD1 itself, the parameters of the glass protection cover 2, the equivalent prism 3, the galvanometer 4, and the air gap between the three optical components.

[0007] Assume that the refractive index of the galvanometer 4 is n1, the equivalent prism 3 is n2, and the protective glass cover is n3; the thickness of the galvanometer 4 is T1, the air gap between the galvanometer 4 and the equivalent prism 3 is T2, the thickness of the equivalent prism 3 is T3, the air gap between the equivalent prism 3 and the protective glass cover is T4, the thickness of the protective glass cover is T5, and the air gap between the protective glass cover and the DMD1 reflector is T6. Then, according to the following formula, the physical size AP1 of the optical aperture on the galvanometer 4 in the horizontal direction can be obtained: H And the vertical physical size AP1V :

[0008] AP1 H =2*((T2+T4+T6)*tan(w)+T5*tan(asin(sin(w) / n3))+T3*tan(asin(sin(w) / n2))+T1*tan(asin(sin(w) / n1)))+HD

[0009] AP1 V =2*((T2+T4+T6)*tan(w)+T5*tan(asin(sin(w) / n3))+T3*tan(asin(sin(w) / n2))+T1*tan(asin(sin(w) / n1)))+HV

[0010] In the above formula, HD is the physical size of DMD1 in the horizontal direction, HV is the physical size of DMD1 in the vertical direction, w is the divergence half-angle of the optical path, and the path of the air gaps T1, T2, T3, T4, T5, and T6 becomes the optical path of the light. When the refractive index remains unchanged, the longer the optical path, the larger the aperture value required by the galvanometer 4.

[0011] When DMD1 is in the ON state, the principal ray is parallel to the system's principal optical axis, and the optical aperture of galvanometer mirror 4 satisfies the numerical relationship given by the above formula. However, this solution requires a relatively large optical aperture for galvanometer mirror 4, significantly increasing system cost. Furthermore, when DMD1 is in the OFF state, requiring a dark field, the long optical path causes high-energy UV light to undergo multiple reflections within the optical engine before entering objective lens 5. This poses a significant risk to the driver components of galvanometer mirror 4, reducing their service life.

[0012] Therefore, it is difficult for the current galvanometer to maintain a relatively stable and long working life while achieving a relatively high resolution. Summary of the Invention

[0013] The present application provides a 3D printing projection system based on DLP technology, which is used to solve the technical problem that it is difficult to maintain a relatively stable and long working life of the galvanometer when achieving a higher resolution.

[0014] In view of this, the present invention provides a 3D printing projection system based on DLP technology, comprising a DMD, a protective glass cover, a galvanometer, an equivalent prism, and an objective lens arranged in sequence along an optical axis; the boundary range of the clear aperture of the galvanometer is defined as:

[0015] An O-XYZ three-dimensional coordinate system is established with the center point of the reflective surface when the DMD is in the NO state as the origin O, the plane where the reflective surface is located as the OXY plane, and the axis passing through the origin O and perpendicular to the OXY plane as the Z axis;

[0016] In the O-XYZ three-dimensional coordinate system, it is assumed that the boundary range of the output light field of the DMD in the NO state is a rectangle A1B1C1D1, and the vertices and coordinate values ​​of the rectangle A1B1C1D1 are: A1(x A1 ,y A1 , z A1 ), B1(x B1 ,y B1 , z B1 ), C1(x C1 ,y C1 , z C1 ), D1(x D1 ,y D1 , z D1 ); The boundary range of the DMD output light field when it is in the OFF state is a rectangle A2B2C2D2, and the vertices and coordinate values ​​of the rectangle A2B2C2D2 are: A2(x A2 ,y A2 , z A2 ), B2(x B2 ,y B2 , z B2 ), C2(x C2 ,y C2 , z C2 ), D2(x D2 ,y D2 , z D2 ); The boundary range of the clear aperture of the galvanometer is a rectangle A3B3C3D3, and the vertices and coordinate values ​​of the rectangle A3B3C3D3 are: A3(x A3 ,y A3 , z A3 ), B3(x B3 ,y B3 , z B3 ), C3(x C3 ,y C3 , z C3 ), D3(x D3 ,y D3 , z D3 );

[0017] The coordinate values ​​of vertices A3, B3, C3, and D3 satisfy the following relationships:

[0018] A3:L A3 / x A3 =x A2 / 0.85,y A3 =y A2 / 0.85, z A3 =0;

[0019] B3:L B3 / x B3 =x B1 / 0.85,y B3 =y B2 / 0.85, z B3 =0;

[0020] C3:L C3 / x C3 =x C1 / 0.85,y C3 =y C1 / 0.85, z C3 =0;

[0021] D3:L D3 / x D3 =x D2 / 0.85,y D3 =y D1 / 0.85, z D3 =0;

[0022] In the above formula, L A3 Indicates the shortest distance from vertex A3 to the origin O, L B3 Indicates the shortest distance from vertex B3 to the origin O, L C3 Indicates the shortest distance from vertex C3 to the origin O, L D3 Indicates the shortest distance from vertex D3 to the origin O;

[0023] At the same time, the horizontal coordinate x of vertex A2 A2 Satisfies the following relationship: A2 =-0.5*AP2 HOFF +AP2 H0 , where AP2 HOFF Indicates the physical size of the DMD's output light field in the horizontal direction when it is in the OFF state, AP2 H0 The vertical coordinate y of the vertex A2 is the horizontal offset distance of the center position of the light field after the output light field of the DMD is converted from the ON state to the OFF state; B2 Satisfies the following relationship: A2 =0.5*AP2 VOFF +AP2 V0 , where AP2 VOFF Indicates the physical size of the DMD's output light field in the vertical direction when it is in the OFF state, AP2 V0represents the vertical offset distance of the center position of the light field after the output light field of the DMD is converted from the ON state to the OFF state; the horizontal coordinate x of the vertex B1 B1 Satisfies the following relationship: B1 =0.5*AP2 HON , where AP2 HON represents the physical size of the optical aperture of the galvanometer in the horizontal direction when the DMD is in the ON state; the ordinate y of the vertex B2 B2 Satisfies the following relationship: B2 =0.5*AP2 VOFF +AP2 V0 ; The horizontal coordinate x of vertex C1 C1 Satisfies the following relationship: C1 =0.5*AP2 HON ; The vertical coordinate y of vertex C1 C1 Satisfies the following relationship: C1 =-0.5*AP2 VON , where AP2 VON represents the physical size of the optical aperture of the galvanometer in the vertical direction when the DMD is in the ON state; the abscissa x of the vertex D2 D2 Satisfies the following relationship: D2 =-0.5*AP2 HOFF +AP2 H0 ; The vertical coordinate y of vertex D1 D1 Satisfies the following relationship: D1 =-0.5*AP2 VON .

[0024] Preferably, the physical size AP2 of the optical aperture of the galvanometer in the horizontal direction when the DMD is in the ON state is HON and the physical size AP2 of the galvanometer's aperture in the vertical direction when the DMD is in the ON state VON The following relationships are satisfied:

[0025] AP2 HON =2*[(T3+T5)*tan(w)+T4*tan(asin(sin(w) / n3)]+T2*tan[asin(sin(w) / n2)]+HD

[0026] AP2 VON =2*[(T3+T5)*tan(w)+T4*tan(asin(sin(w) / n3)]+T2*tan[asin(sin(w) / n2)]+HV

[0027] Wherein, n1 represents the refractive index of the equivalent prism, n2 represents the refractive index of the galvanometer, n3 represents the refractive index of the protective glass cover, T1 represents the air gap between the galvanometer and the equivalent prism, T2 represents the thickness of the galvanometer, T3 represents the air gap between the equivalent prism and the protective glass cover, T4 represents the thickness of the protective glass cover, T5 represents the air gap between the protective glass cover and the DMD, HD represents the physical size of the DMD in the horizontal direction, HV represents the physical size of the DMD in the vertical direction, and w is the divergence half angle of the galvanometer.

[0028] Preferably, the physical size AP2 in the horizontal direction of the output light field of the DMD when it is in the OFF state is HOFF and the physical size AP2 in the vertical direction when the output light field of the DMD is in the OFF state VOFF The following relationships are satisfied:

[0029] AP2 HOFF =2*[(T3+T5)*tan(w)+T4*tan(asin(sin(w) / n3)]+T2*tan[asin(sin(w) / n

[0030] 2)]+HD / cos(θ);

[0031] AP2 VOFF =2*[(T3+T5)*tan(w)+T4*tan(asin(sin(w) / n3)]+T2*tan[asin(sin(w) / n

[0032] 2)]+HV / cos(θ);

[0033] Where θ is the angle between the incident light on the DMD and the Z axis.

[0034] Preferably, the horizontal offset distance AP2 of the center position of the light field after the output light field of the DMD is converted from the ON state to the OFF state is H0 The vertical offset distance AP2 of the center position of the light field after the output light field of the DMD is converted from the ON state to the OFF state V0 The following relationships are satisfied:

[0035] AP2 H0 =(T2+T3+T4+T5)*sin(-θ)*sin(α)

[0036] AP2 V0 =(T2+T3+T4+T5)*sin(θ)*cos(α)

[0037] Where α is the vector angle of the projection of the OFF state normal vector on the XOY plane.

[0038] Preferably, the glass material of the galvanometer is H-K9L / B270.

[0039] It can be seen from the above technical solutions that the present invention has the following advantages:

[0040] The present invention provides a 3D printing projection system based on DLP technology. By sequentially arranging a DMD, a protective glass cover, a galvanometer mirror, an equivalent prism, and an objective lens along the optical axis, the requirements for the galvanometer mirror's aperture are reduced. Furthermore, by defining the coordinates of each vertex within a rectangular boundary range of the galvanometer mirror's aperture, a minimum boundary range of the defined galvanometer mirror's aperture is obtained. This allows incident light from the DMD in any state to completely pass through the galvanometer mirror, thereby preserving the circuit structure outside the galvanometer mirror glass. This allows the galvanometer mirror to maintain a relatively stable and long operating life while achieving a high resolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a structural diagram of a projection system in the prior art;

[0042] Figure 2 A schematic diagram of a 3D printing projection system based on DLP technology provided in an embodiment of the present application;

[0043] Figure 3 Schematic diagram of the light field emitted by the galvanometer when the DMD provided in the embodiment of the present application is in the ON state;

[0044] Figure 4 Schematic diagram of the light field emitted by the galvanometer when the DMD provided in the embodiment of the present application is in the OFF state;

[0045] Figure 5 A schematic diagram of the O-XYZ three-dimensional coordinate system provided in an embodiment of the present application;

[0046] Figure 6 A schematic diagram of the boundary range of the limited light aperture of the galvanometer provided in an embodiment of the present application. DETAILED DESCRIPTION

[0047] In order to help those skilled in the art better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0048] For easier understanding, see Figure 2 The present invention provides a 3D printing projection system based on DLP technology, comprising a DMD 1, a protective glass cover 2, a galvanometer 4, an equivalent prism 3 and an objective lens 5 arranged in sequence along the optical axis;

[0049] It can be understood that, due to the placement of the optical elements in this embodiment, the incident light will first pass through the DMD1, and then enter the protective glass cover 2, the galvanometer 4, the equivalent prism 3 and the objective lens 5 in sequence. Since the galvanometer 4 is closer to the equivalent prism 3 and DMD1, Figure 1 Compared with the projection system in FIG, the requirement for the clear aperture of the galvanometer 4 is lower.

[0050] Comparison Figure 1 In general, the area of ​​the light aperture of the galvanometer mirror 4 obtained in this embodiment is much smaller, which will help the projection system to reduce costs while ensuring the imaging effect.

[0051] However, the light-clearing aperture obtained in this embodiment only takes into account the case where DMD1 is in the ON state. In a high-energy working environment where the light source is in the UV band, this light-clearing aperture will cause the UV light to be deflected in the optical path when DMD1 is in the non-ON state, and will directly irradiate the internal structure of the optical machine, which will cause greater damage to the driving part of the galvanometer 4 and will directly affect the working life of the system.

[0052] Therefore, based on the arrangement of the projection system structure of this embodiment, the boundary range of the light aperture of the limited galvanometer mirror 4 is limited, and the specific definition is as follows:

[0053] like Figure 3 As shown in FIG, when the DMD is in the ON state, the light field of the galvanometer can be regarded as expanding within a certain range along the horizontal and vertical directions of the DMD respectively. When the clear aperture of the galvanometer is ≥ the light field in the ON state, the projection system can work normally. Otherwise, the light flux of the projection system will be attenuated.

[0054] Assuming that n1 represents the refractive index of the equivalent prism, n2 represents the refractive index of the galvanometer, n3 represents the refractive index of the protective glass cover, T1 represents the air gap between the galvanometer and the equivalent prism, T2 represents the thickness of the galvanometer, T3 represents the air gap between the equivalent prism and the protective glass cover, T4 represents the thickness of the protective glass cover, T5 represents the air gap between the protective glass cover and the DMD, HD represents the physical size of the DMD in the horizontal direction, HV represents the physical size of the DMD in the vertical direction, and w is the divergence half angle of the galvanometer. Then the physical size of the clear aperture of the galvanometer in the horizontal direction when the DMD is in the ON state is AP2 HON The physical size AP2 of the galvanometer's aperture in the vertical direction when the DMD is in the ON stateVON The following relationships are satisfied:

[0055] AP2 HON =2*[(T3+T5)*tan(w)+T4*tan(asin(sin(w) / n3)]+T2*tan[asin(sin(w) / n2)]+HD

[0056] AP2 VON =2*[(T3+T5)*tan(w)+T4*tan(asin(sin(w) / n3)]+T2*tan[asin(sin(w) / n2)]+HV;

[0057] It should be noted that, in a general example, the divergence half-angle w of the galvanometer is set to 17°.

[0058] When the DMD is in the OFF state, according to the working principle of the DMD, its light field will be offset. The offset light field is as follows: Figure 4 shown.

[0059] like Figure 5 As shown, the center point of the reflecting surface when the DMD is in the NO state is taken as the origin O, the plane where the reflecting surface is located is the OXY plane, and the axis perpendicular to the OXY plane through the origin O is the Z axis to establish the O-XYZ three-dimensional coordinate system; since the deflection angle of the DMD in the ON state, OFF state and flat state is 17 degrees, the angle between the incident light and the Z axis is set to θ, and generally θ is 34 degrees. When the DMD is in the ON state, on the ZOX plane, the angle between the incident light and the Z axis is 17 degrees. Therefore, under the action of Snell's law, the ON state outgoing light along The Z axis is perpendicular to the DMD surface direction. The OFF state normal vector of the DMD is a two-dimensional angle. The vector angle of the OFF state normal vector projected on the XOY plane is set to α. Generally, α is 45 degrees, and the spatial angle between the OFF state normal vector and the Z axis is 17 degrees. The incident light is reflected to the OFF state through the DMD. At this time, the light field reflected by the DMD is emitted along the direction of the OFF state outgoing light, and the angle between the OFF state outgoing light vector and the Z axis is 34 degrees. The physical size AP2 in the horizontal direction of the outgoing light field of the DMD when it is in the OFF state HOFF The physical size AP2 in the vertical direction when the DMD's output light field is in the OFF state VOFF The following relationships are satisfied:

[0060] AP2 HOFF =2*[(T3+T5)*tan(w)+T4*tan(asin(sin(w) / n3)]+T2*tan[asin(sin(w) / n

[0061] 2)]+HD / cos(θ);

[0062] AP2 VOFF =2*[(T3+T5)*tan(w)+T4*tan(asin(sin(w) / n3)]+T2*tan[asin(sin(w) / n

[0063] 2)]+HV / cos(θ);

[0064] Where θ is the angle between the incident light on the DMD and the Z axis.

[0065] like Figure 6 As shown in the figure, when the DMD is in the OFF state, the center position of its output light field will be offset compared with the ON state. Taking the center position of the reflecting surface when the DMD is in the NO state as the original point, the horizontal offset distance of the center position of the light field after the DMD output light field is converted from the ON state to the OFF state is AP2 H0 The vertical offset distance AP2 of the center position of the light field after the DMD output light field is converted from the ON state to the OFF state V0 The following relationships are satisfied:

[0066] AP2 H0 =(T2+T3+T4+T5)*sin(-θ)*sin(α)

[0067] AP2 V0 =(T2+T3+T4+T5)*sin(θ)*cos(α)

[0068] Where α is the vector angle of the projection of the OFF state normal vector on the XOY plane.

[0069] In order for the projection system to work properly and prevent the emitted light from hitting the peripheral circuit of the galvanometer, it is necessary to make the emitted light fall on the glass of the galvanometer. Therefore, the boundary range of the galvanometer's light aperture needs to include the boundary range when the DMD's output light field is in the NO state and the boundary range when the DMD's output light field is in the OFF state. At the same time, in order to reduce costs, it is necessary to limit the minimum boundary range of the galvanometer's light aperture. The specific limitations are as follows:

[0070] like Figure 6 As shown in the O-XYZ three-dimensional coordinate system, the boundary range of the DMD itself is a rectangle A0B0C0D0. Assuming that the boundary range of the output light field of the DMD is in the NO state, the vertices and coordinate values ​​of the rectangle A1B1C1D1 are: A1(x A1 ,y A1 , z A1 ), B1(x B1 ,y B1 , zB1 ), C1(x C1 ,y C1 , z C1 ), D1(x D1 ,y D1 , z D1 ); The boundary range of the DMD's output light field when it is in the OFF state is a rectangle A2B2C2D2, and the vertices and coordinate values ​​of the rectangle A2B2C2D2 are: A2(x A2 ,y A2 , z A2 ), B2(x B2 ,y B2 , z B2 ), C2(x C2 ,y C2 , z C2 ), D2(x D2 ,y D2 , z D2 ); The boundary range of the galvanometer's aperture is a rectangle A3B3C3D3, and the vertices and coordinates of the rectangle A3B3C3D3 are: A3(x A3 ,y A3 , z A3 ), B3(x B3 ,y B3 , z B3 ), C3(x C3 ,y C3 , z C3 ), D3(x D3 ,y D3 , z D3 );

[0071] The coordinate values ​​of vertices A3, B3, C3, and D3 satisfy the following relationships:

[0072] A3:L A3 / x A3 =x A2 / 0.85,y A3 =y A2 / 0.85, z A3 =0;

[0073] B3:L B3 / x B3 =x B1 / 0.85,y B3 =y B2 / 0.85, z B3 =0;

[0074] C3:L C3 / x C3 =x C1 / 0.85,yC3 =y C1 / 0.85, z C3 =0;

[0075] D3:L D3 / x D3 =x D2 / 0.85,y D3 =y D1 / 0.85, z D3 =0;

[0076] In the above formula, L A3 Indicates the shortest distance from vertex A3 to the origin O, L B3 Indicates the shortest distance from vertex B3 to the origin O, L C3 Indicates the shortest distance from vertex C3 to the origin O, L D3 Indicates the shortest distance from vertex D3 to the origin O;

[0077] At the same time, the horizontal coordinate x of vertex A2 A2 Satisfies the following relationship: A2 =-0.5*AP2 HOFF +AP2 H0 , where AP2 HOFF Indicates the physical size of the DMD's output light field in the horizontal direction when it is in the OFF state, AP2 H0 Indicates the horizontal offset distance of the center position of the light field after the DMD's output light field is converted from the ON state to the OFF state; the vertical coordinate y of vertex A2 B2 Satisfies the following relationship: A2 =0.5*AP2 VOFF +AP2 V0 , where AP2 VOFF Indicates the physical size of the DMD's output light field in the vertical direction when it is in the OFF state, AP2 V0 It represents the vertical offset distance of the center position of the light field after the DMD output light field is converted from the ON state to the OFF state; the horizontal coordinate x of the vertex B1 B1 Satisfies the following relationship: B1 =0.5*AP2 HON , where AP2 HON The y-axis represents the horizontal physical size of the galvanometer's aperture when the DMD is in the ON state; the ordinate y of vertex B2 B2 Satisfies the following relationship: B2 =0.5*AP2 VOFF +AP2 V0 ; The horizontal coordinate x of vertex C1 C1 Satisfies the following relationship: C1 =0.5*AP2 HON; The vertical coordinate y of vertex C1 C1 Satisfies the following relationship: C1 =-0.5*AP2 VON , where AP2 VON Indicates the physical size of the galvanometer's aperture in the vertical direction when the DMD is in the ON state; the abscissa x of vertex D2 D2 Satisfies the following relationship: D2 =-0.5*AP2 HOFF +AP2 H0 ; The vertical coordinate y of vertex D1 D1 Satisfies the following relationship: D1 =-0.5*AP2 VON , then the coordinates of the vertices on the boundary range of the galvanometer's clear aperture satisfy the above formula, and the rectangle A3B3C3D3 formed by connecting the vertices A3, B3, C3, and D3 is the minimum boundary range of the galvanometer's clear aperture after definition.

[0078] Furthermore, the glass material of the galvanometer is H-K9L / B270.

[0079] For a 0.3-inch DMD platform, to ensure that UV light can pass through the galvanometer's clear aperture regardless of the DMD's state, thereby preventing damage to the galvanometer structure and extending its service life, Tables 1 through 4 show some implementation examples of the relationship between air gap T3 and the galvanometer's clear aperture when the galvanometer thicknesses are 2mm, 1.5mm, 1mm, and 0.7mm, respectively.

[0080] Table 1 The relationship between the air gap T3 and the clear aperture of the galvanometer when the galvanometer thickness is 2 mm

[0081]

[0082]

[0083] Table 2 The relationship between the air gap T3 and the clear aperture of the galvanometer when the galvanometer thickness is 1.5 mm

[0084] Serial number Air gap T3 / mm Galvanometer long side / mm Galvanometer short side / mm 1 2.5 10.5 14.4 2 2.25 10.1 14 3 2 9.7 13.6 4 1.75 9.3 13.2 5 1.5 8.9 12.8 6 1.25 8.5 12.5 7 1 8.1 12.1 8 0.75 7.8 11.7 9 0.5 7.4 11.3 10 0.25 7 11

[0085] Table 3 The relationship between the air gap T3 and the clear aperture of the galvanometer when the galvanometer thickness is 1 mm

[0086]

[0087]

[0088] Table 4 The relationship between the air gap T3 and the clear aperture of the galvanometer when the galvanometer thickness is 0.7 mm

[0089]

[0090]

[0091] The length of the long side and the length of the short side of the galvanometer in the above embodiment constitute a limited minimum light-transmitting aperture of the galvanometer, which allows the incident light to pass completely through the galvanometer glass without destroying the galvanometer circuit structure, so that the projection system can maintain a relatively stable and long working life of the galvanometer while achieving high resolution.

[0092] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A 3D printing projection system based on DLP technology, comprising a DMD, a protective glass cover, a galvanometer, an equivalent prism, and an objective lens arranged in sequence along an optical axis; characterized in that: The boundary range of the clear aperture of the galvanometer is defined as: An O-XYZ three-dimensional coordinate system is established with the center point of the reflective surface when the DMD is in the ON state as the origin O, the plane where the reflective surface is located as the OXY plane, and the axis passing through the origin O and perpendicular to the OXY plane as the Z axis; In the O-XYZ three-dimensional coordinate system, it is assumed that the boundary range of the output light field of the DMD when it is in the ON state is a rectangle A1B1C1D1, and the vertices and coordinate values ​​of the rectangle A1B1C1D1 are: A1(x A1 ,y A1 , z A1 ), B1(x B1 ,y B1 , z B1 ), C1(x C1 ,y C1 , z C1 ), D1(x D1 ,y D1 , z D1 The boundary range of the outgoing light field of the DMD when it is in the OFF state is a rectangle A2B2C2D2, and the vertices and coordinate values ​​of the rectangle A2B2C2D2 are: A2(x A2 ,y A2 , z A2 ), B2(x B2 ,y B2 , z B2 ), C2(x C2 ,y C2 , z C2 ), D2(x D2 ,y D2 , z D2 ); The boundary range of the clear aperture of the galvanometer is a rectangle A3B3C3D3, and the vertices and coordinate values ​​of the rectangle A3B3C3D3 are: A3(x A3 ,y A3 , z A3 ), B3(x B3 ,y B3 , z B3 ), C3(x C3 ,y C3 , z C3 ), D3(x D3 ,y D3 , z D3 ); The coordinate values ​​of vertices A3, B3, C3, and D3 satisfy the following relationships: A3:L A3 / x A3 =x A2 / 0.85,y A3 =y A2 / 0.85,z A3 =0; B3:L B3 / x B3 =x B1 / 0.85,y B3 =y B2 / 0.85,z B3 =0; C3:L C3 / x C3 =x C1 / 0.85,y C3 =y C1 / 0.85,z C3 =0; D3:L D3 / x D3 =x D2 / 0.85,y D3 =y D1 / 0.85,z D3 =0; In the above formula, L A3 Indicates the shortest distance from vertex A3 to the origin O, L B3 Indicates the shortest distance from vertex B3 to the origin O, L C3 Indicates the shortest distance from vertex C3 to the origin O, L D3 Indicates the shortest distance from vertex D3 to the origin O; At the same time, the horizontal coordinate x of vertex A2 A2 Satisfies the following relationship: A2 =-0.5*AP2 HOFF +AP2 H0 , where AP2 HOFF Indicates the physical size of the output light field of the DMD in the horizontal direction when the output light field is in the OFF state, AP2 H0 The vertical coordinate y of the vertex A2 is the horizontal offset distance of the center position of the output light field after the output light field of the DMD is converted from the ON state to the OFF state; B2 Satisfies the following relationship: A2 =0.5*AP2 VOFF +AP2 V0 , where AP2 VOFF Indicates the physical size of the output light field of the DMD in the vertical direction when the output light field is in the OFF state, AP2 V0 The vertical offset distance of the center position of the outgoing light field of the DMD after the outgoing light field is converted from the ON state to the OFF state; the horizontal coordinate x of the vertex B1 B1 Satisfies the following relationship: B1 =0.5*AP2 HON , where AP2 HON represents the physical size of the optical aperture of the galvanometer in the horizontal direction when the DMD is in the ON state; the ordinate y of the vertex B2 B2 Satisfies the following relationship: B2 =0.5*AP2 VOFF +AP2 V0 ; The horizontal coordinate x of vertex C1 C1 Satisfies the following relationship: C1 =0.5*AP2 HON ; The vertical coordinate y of vertex C1 C1 Satisfies the following relationship: C1 =-0.5*AP2 VON , where AP2 VON represents the physical size of the optical aperture of the galvanometer in the vertical direction when the DMD is in the ON state; the abscissa x of the vertex D2 D2 Satisfies the following relationship: D2 =-0.5*AP2 HOFF +AP2 H0 ; The vertical coordinate y of vertex D1 D1 Satisfies the following relationship: D1 =-0.5*AP2 VON ; The physical size AP2 of the galvanometer's aperture in the horizontal direction when the DMD is in the ON state HON and the physical size AP2 of the galvanometer's aperture in the vertical direction when the DMD is in the ON state VON The following relationships are satisfied: <h2 style=";text-align:left;direction:ltr">AP2<h2 style=";text-align:left;direction:ltr"> HON <h2 style=";text-align:left;direction:ltr"> = 2*[(T3+T5)*tan(w)+T4*tan(asin(sin(w) / n3)]+T2*tan[asin(sin(w) / n2) ]+HD <h2 style=";text-align:left;direction:ltr">AP2<h2 style=";text-align:left;direction:ltr"> VON <h2 style=";text-align:left;direction:ltr"> = 2*[(T3+T5)*tan(w)+T4*tan(asin(sin(w) / n3)]+T2*tan[asin(sin(w) / n2) ]+HV Wherein, n1 represents the refractive index of the equivalent prism, n2 represents the refractive index of the galvanometer, n3 represents the refractive index of the protective glass cover, T1 represents the air gap between the galvanometer and the equivalent prism, T2 represents the thickness of the galvanometer, T3 represents the air gap between the equivalent prism and the protective glass cover, T4 represents the thickness of the protective glass cover, T5 represents the air gap between the protective glass cover and the DMD, HD represents the physical size of the DMD in the horizontal direction, HV represents the physical size of the DMD in the vertical direction, and w is the divergence half angle of the galvanometer.

2. The projection system for 3D printing based on DLP technology according to claim 1, characterized in that: The physical size AP2 in the horizontal direction of the output light field when the output light field of the DMD is in the OFF state HOFF and the physical size AP2 in the vertical direction of the output light field when the output light field of the DMD is in the OFF state VOFF The following relationships are satisfied: <h2 style=";text-align:left;direction:ltr">AP2<h2 style=";text-align:left;direction:ltr"> HOFF <h2 style=";text-align:left;direction:ltr"> = 2*[(T3+T5)*tan(w)+T4*tan(asin(sin(w) / n3)]+T2*tan[asin(sin(w) / n 2)]+HD / cos(θ); <h2 style=";text-align:left;direction:ltr">AP2<h2 style=";text-align:left;direction:ltr"> VOFF <h2 style=";text-align:left;direction:ltr"> = 2*[(T3+T5)*tan(w)+T4*tan(asin(sin(w) / n3)]+T2*tan[asin(sin(w) / n 2)]+HV / cos(θ); Where θ is the angle between the incident light on the DMD and the Z axis.

3. The projection system for 3D printing based on DLP technology according to claim 2, characterized in that: The horizontal offset distance AP2 of the center position of the output light field of the DMD after the output light field is converted from the ON state to the OFF state H0 The vertical offset distance AP2 of the center position of the output light field after the output light field of the DMD is converted from the ON state to the OFF state V0 The following relationships are satisfied: AP2 H0 =(T2+T3+T4+T5)*sin(-θ)*sin(α) AP2 V0 =(T2+T3+T4+T5)*sin(θ)*cos(α) Where α is the vector angle of the projection of the OFF state normal vector on the XOY plane.

4. The projection system for 3D printing based on DLP technology according to claim 1, characterized in that: The glass material of the galvanometer is H-K9L or B270.

Images