Zero-distortion ultra-high-definition lens applied to DLP 3D printing

Abstract

The invention provides a zero-distortion ultra-high-definition lens applied to DLP 3D printing, and relates to the technical field of optics. Comprising a first lens group, a diaphragm, a second lens group, a galvanometer, a light splitting device, protective glass and an imaging surface which are arranged in sequence, the imaging surface is used for emitting light rays, the protective glass is used for preventing dust from falling onto the imaging surface and the light splitting device, the galvanometer is used for adjusting imaging pixels, the light splitting device is used for splitting the light rays, and the diaphragm is used for controlling the light inlet amount of the split light rays. The first group lens and the second group lens are both used for correcting aberration; the problems that in the prior art, a DLP 3D printing objective lens is large in distortion, imaging is not clear enough, and cost is too high are solved.

Description

Technical Field

[0001] The present invention relates to the field of photocuring 3D printing, and in particular to the design of a zero-distortion ultra-high-definition lens for DLP 3D printing. Background Art

[0002] 3D printing technology, as a rapid prototyping technology, its special production and manufacturing method has realized people's pursuit of efficient, fine, personalized and customized products. The technology has been developed to provide more than just models for industrial design or machinery manufacturing industries. Its application involves jewelry, food, industrial design, architecture, engineering, automobiles, aerospace, medical industry, education, geographic information systems, civil engineering, military and other fields. The principle of light-curing 3D printing technology is that the activation energy generated by ultraviolet light with the highest energy in the spectrum can break the CC bond of unsaturated polyester resin and generate free radicals to solidify the resin.

[0003] At present, photocuring 3D printing technology is mainly divided into three types: SLA (laser point source photocuring), DLP (projector surface light source curing), and LCD (liquid crystal surface light source curing). Among them, DLP photocuring 3D printing technology has been widely used due to its advantages of high precision and high efficiency.

[0004] DLP 3D printing light-curing technology uses UV LED to illuminate the DMD surface, and uses a projection lens to image the DMD surface onto the light-curing surface for molding and printing. Currently, with the increasing requirements for part printing accuracy, the requirements for image quality and distortion of the projection lens are also correspondingly increased.

[0005] Most existing DLP 3D printing objective lenses have large distortion. For high-precision printing occasions, the objective lens system is required to have low distortion or even zero distortion, and at the same time, there are extremely high requirements for the imaging quality of the objective lens. In addition, the existing DLP 3D printing objective lenses cannot guarantee low distortion and ultra-high-definition imaging quality at different working distances. At this time, the objective lens system needs to be redesigned and processed, which increases the development cost of the objective lens. Summary of the invention

[0006] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a zero-distortion ultra-high-definition lens for DLP 3D printing. The present invention solves the problems in the prior art that the DLP 3D printing objective lens has large distortion, unclear imaging and high cost.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] A zero-distortion ultra-high-definition lens for DLP 3D printing, comprising:

[0009] A first lens group, an aperture, a second lens group, a galvanometer, a beam splitter, a protective glass and an imaging surface are arranged in sequence;

[0010] The imaging surface is used to emit light, the protective glass is used to prevent dust from falling onto the imaging surface and the spectroscopic device, the galvanometer is used to adjust the pixels of the imaging, the spectroscopic device is used to split the light, the aperture is used to control the amount of light entering after the splitting, and the first group of lenses and the second group of lenses are both used to correct aberrations;

[0011] The first group of lenses includes: a first lens, a second lens and a third lens, the first lens and the second lens are both lenses with negative optical power, and the third lens is a lens with positive optical power;

[0012] The second group of lenses includes: a fourth lens, a fifth lens, and a sixth lens;

[0013] The sixth lens is a lens with positive power, and the fourth lens and the fifth lens constitute a doublet lens with negative power;

[0014] The first lens, the second lens and the third lens are all placed before the aperture stop, and the fourth lens, the fifth lens and the sixth lens are all placed after the aperture stop.

[0015] Preferably, the first lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the galvanometer, the beam splitter and the protective glass are all made of glass.

[0016] Preferably, both the second lens and the sixth lens are aspherical lenses.

[0017] Preferably, the ratio of the focal length of the first group of lenses to the focal length of the zoom objective lens system is in the range of 4.18 to 4.21; the ratio of the focal length of the first lens to the focal length of the first group of lenses is in the range of -1.135 to -1.306; the ratio of the focal length of the second lens to the focal length of the first group of lenses is in the range of -0.741 to -0.736; the ratio of the focal length of the third lens to the focal length of the first group of lenses is in the range of 0.736 to 0.741; the ratio of the focal length of the second group of lenses to the focal length of the zoom objective lens system is in the range of 2.067 to 2.085, the ratio of the focal length of the doublet lens with negative optical power to the focal length of the second group of lenses is in the range of -115.982 to -115.972; the ratio of the focal length of the sixth lens to the focal length of the second group of lenses is less than 1.157.

[0018] Preferably, the MTF value of each field of view of the zoom objective system is greater than 0.79.

[0019] Preferably, the lens of the zoom objective system adopts a 0.47-inch DMD chip.

[0020] The present invention discloses the following technical effects:

[0021] The invention provides a zero-distortion ultra-high-definition lens for DLP 3D printing, comprising: a first lens group, an aperture, a second lens group, a galvanometer, a spectroscopic device, a protective glass and an imaging surface arranged in sequence; the imaging surface is used to emit light, the protective glass is used to prevent dust from falling on the imaging surface and the spectroscopic device, the galvanometer is used to adjust the pixels of the imaging, the spectroscopic device is used to split the light, the aperture is used to control the amount of light entering the split light, and the first group lens and the second group lens are both used to correct aberrations; the first group lens comprises: a first lens, a second lens and a third lens, the first lens and the second lens are both lenses with negative focal power, and the third lens is a lens with positive focal power; the second group lens comprises: a fourth lens, a fifth lens and a sixth lens; the sixth lens is a lens with positive focal power, and the fourth lens and the fifth lens constitute a doublet lens with negative focal power; the first lens, the second lens and the third lens are all placed in front of the aperture, and the fourth lens, the fifth lens and the sixth lens are all placed behind the aperture.The 3D printing projection lens disclosed in the present invention has a small total length and extremely low distortion, which meets the needs of desktop-level high-precision 3D printing equipment; the 3D printing projection lens disclosed in the present invention is compatible with XPR technology, and when using XPR, 4K resolution is achieved; when not using XPR, 1080P resolution is achieved; the 3D printing projection lens disclosed in the present invention has a full-field MTF higher than 0.79; the distortion is less than 0.003%, and ultra-high-definition zero-distortion high-quality imaging can be achieved; the 3D printing projection lens disclosed in the present invention can meet high-quality imaging standards for different working distances by simply changing the air spacing between the lenses, which is beneficial to improving the flexibility of the objective lens in the use range and reducing the cost of objective lens development; the 3D printing projection lens disclosed in the present invention, the lenses are all made of glass material, which can effectively avoid the problem of serious focus deviation caused by the strong energy of the 405nm short-wave light source used in 3D printing and the easy heat absorption of plastic aspheric surfaces; the first lens uses a meniscus lens, which can reduce the incidence of light The field of view of the subsequent system is helpful to correct the distortion and coma of the system; the 3D printing projection lens disclosed in the present invention has a spot radius (<2um) much smaller than the pixel size (5.4um), which has obvious advantages for 3D printing, which focuses on the spot size and energy concentration; the 3D printing projection lens disclosed in the present invention has a high transmittance of the selected lens material to the light of 405nm wavelength, all exceeding 95% / 10mm, and the number of lenses is small, only 6 pieces, and the energy absorption of the whole imaging system is very small, which helps to improve the brightness of the system, reduce the heat generation of the whole projection system, and improve the stability of 3D printing; the 3D printing projection lens disclosed in the present invention has a design wavelength of 395nm, 405nm, and 410nm, which includes the wavelength fluctuation of the actual light source, so that the lens design is more in line with the actual situation; the 3D printing projection lens disclosed in the present invention uses only 6 lenses, which effectively reduces the lens cost and assembly difficulty compared with other lens designs with more than ten lenses. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1 A schematic diagram of a zero-distortion ultra-high-definition lens structure for DLP 3D printing provided by an embodiment of the present invention;

[0024] Figure 2 The objective lens layout diagram provided by the embodiment of the present invention when the working distance d=140mm;

[0025] Figure 3 A first spatial frequency MTF diagram provided by an embodiment of the present invention;

[0026] Figure 4 A first point diagram provided by an embodiment of the present invention;

[0027] Figure 5 A first field curvature evaluation graph provided by an embodiment of the present invention;

[0028] Figure 6 A first distortion evaluation graph provided by an embodiment of the present invention;

[0029] Figure 7 A first relative illumination map provided by an embodiment of the present invention;

[0030] Figure 8 The objective lens layout diagram provided by the embodiment of the present invention when the working distance d=200mm;

[0031] Fig. 9 A second spatial frequency MTF diagram provided by an embodiment of the present invention;

[0032] Fig.10 A second point diagram provided by an embodiment of the present invention;

[0033] Fig.11 A second field curvature evaluation graph provided by an embodiment of the present invention;

[0034] Fig.12 A second distortion evaluation graph provided by an embodiment of the present invention;

[0035] Fig.13 A second relative illumination map provided by an embodiment of the present invention;

[0036] Fig.14 The objective lens layout diagram provided by the embodiment of the present invention when the working distance d=300mm;

[0037] Fig.15 A third spatial frequency MTF diagram provided by an embodiment of the present invention;

[0038] Fig.16 A third point diagram provided for an embodiment of the present invention;

[0039] Fig.17 A third field curvature evaluation diagram provided by an embodiment of the present invention;

[0040] Fig.18 A third distortion evaluation graph provided by an embodiment of the present invention;

[0041] Fig.19 A third relative illumination diagram provided by an embodiment of the present invention;

[0042] Description of reference numerals:

[0043] 1-first lens group, 2-second lens group, 3-aperture, 4-galvanometer, 5-beam splitter, 6-protective glass, 7-imaging surface, G1-first lens, GM2-second lens, G3-third lens, G4-fourth lens, G5-fifth lens, GM6-sixth lens. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] like Figure 1 As shown, the present invention provides a zero-distortion ultra-high-definition lens for DLP 3D printing, further comprising:

[0047] The first lens G1 group 1, the aperture 3, the second lens GM2 group 2, the galvanometer 4, the beam splitter 5, the protective glass 6 and the imaging surface 7 are arranged in sequence;

[0048] The imaging surface 7 is used to emit light, the protective glass 6 is used to prevent dust from falling onto the imaging surface 7 and the light splitting device 5, the galvanometer 4 is used to adjust the pixels of the imaging, the light splitting device 5 is used to split the light, the aperture 3 is used to control the amount of light entering after the light is split, and the first group of lenses and the second group of lenses are both used to correct aberrations;

[0049] The first lens group includes: a first lens G1, a second lens GM2 and a third lens G3, the first lens G1 and the second lens GM2 are lenses with negative refractive power, and the third lens G3 is a lens with positive refractive power;

[0050] The second lens group includes: a fourth lens G4, a fifth lens G5, and a sixth lens GM6;

[0051] The sixth lens GM6 is a lens with positive power, and the fourth lens G4 and the fifth lens G5 constitute a doublet lens with negative power;

[0052] The first lens G1 , the second lens GM2 , and the third lens G3 are all disposed before the aperture 3 , and the fourth lens G4 , the fifth lens G5 , and the sixth lens GM6 are all disposed after the aperture 3 .

[0053] Specifically, the 2D Layout of the objective system is as follows: Figure 1 G1, GM2, G3, G4, G5, GM6, galvanometer 4, light splitting device 5, and protective glass 6 are all made of glass materials.

[0054] The first group of lenses is located before the aperture 3, the first lens of the first group is a lens with negative optical power, the second lens is a lens with negative optical power, and the third lens is a lens with positive optical power;

[0055] The second group of lenses is located after the aperture 3. The first lens of the second group is a double-cemented lens with negative optical focal length. The combination of G4 and G5 as a double-cemented lens is beneficial to the correction of chromatic aberration and the reduction of tolerance sensitivity. The second lens is a lens with positive optical focal length. GM6 is set to be aspherical, which is beneficial to the correction of spherical aberration and coma.

[0056] Figure 1 Among them, S1, S2, S3, S4, S5, and S6 are air spaces between the lenses, which can be changed when the objective lens is used at different working distances, and the focal length of the objective lens system will also change.

[0057] Furthermore, both the second lens GM2 and the sixth lens GM6 are aspherical lenses.

[0058] Further, the ratio of the focal length of the first group lens to the focal length of the zoom objective lens system is in the range of 4.18 to 4.21; the ratio of the focal length of the first lens G1 to the focal length of the first group lens is in the range of -1.135 to -1.306; the ratio of the focal length of the second lens GM2 to the focal length of the first group lens is in the range of -0.741 to -0.736; the ratio of the focal length of the third lens G3 to the focal length of the first group lens is in the range of 0.736 to 0.741; the ratio of the focal length of the second group lens to the focal length of the zoom objective lens system is in the range of 2.067 to 2.085, the ratio of the focal length of the doublet lens with negative optical power to the focal length of the second group lens is in the range of -115.982 to -115.972; the ratio of the focal length of the sixth lens GM6 to the focal length of the second group lens is less than 1.157.

[0059] Specifically, each lens meets the following requirements:

[0060] 4.18 <f1 / f<4.21;

[0061] -1.315 <fG1 / f1<-1.306;

[0062] -0.741 <fGM2 / f1<-0.736;

[0063] 0.736 <fG3 / f1<0.741;

[0064] 2.067 <f2 / f<2.085;

[0065] -115.982 <fG4G5 / f2<-115.972;

[0066] fGM6 / f2<1.157;

[0067] f is the focal length of the objective lens system; f1 is the focal length of the first group 1; fG1 is the focal length of lens G1; fGM2 is the focal length of the aspheric lens GM2; fG3 is the focal length of lens G3; f2 is the focal length of the second group 2; fG4G5 is the focal length of the doublet lens G4G5; fGM6 is the focal length of the aspheric lens GM6.

[0068] Furthermore, the MTF value of each field of view of the zoom objective system is greater than 0.79.

[0069] Specifically, the specific design parameters of the objective lens system are shown in Table 1, wherein surface numbers 1 to 12 represent the surface of each lens from the first spherical lens to the sixth aspherical lens in sequence; number STOP represents the surface of the aperture 3; number OBJ represents the object; surface numbers 13 and 14 represent the surface of the galvanometer 4; surface numbers 15 and 16 represent the surface of the prism; surface numbers 17 and 18 represent the surface of the protective glass 6; number IMA represents the image plane; the aspheric coefficients of the second aspheric lens and the sixth aspheric lens are shown in Table 2; the air gaps S1 to S6 between the lenses have their own preferred solutions in the specific embodiments when the objective lens is at different working distances d, and each specific embodiment will be explained below.

[0070] Table 1 Specific parameters of objective lens system

[0071]

[0072]

[0073] Table 2 is a table of coefficients of various orders of aspherical lenses GM2 and GM6. Table 2 is as follows:

[0074] Table 2 Aspherical lens GM2, GM6 various order coefficients

[0075]

[0076]

[0077] Specifically, when the working distance d=140 mm, the parameters of the air intervals S1 to S6 between the lenses are shown in the following table:

[0078] Table 3 Parameters of air gaps S1 to S6 between lenses when working distance d = 140 mm

[0079] S1(mm) S2(mm) S3(mm) S4(mm) S5(mm) S6(mm) 4.296 31.5 6.8 17.9 0.5 2.200

[0080] like Figure 2 As shown, the focal length of the lens is 11.962mm, the FOV is 62.59°, and the F / NO is 1.875.

[0081] Further, such as Figure 3 As shown, the MTF (English name: Modulation Transfer Function) index is the most accurate and scientific evaluation standard for lenses at present. The vertical axis (Modulus of the OTF) is the contrast. The closer it is to 1, the better the lens imaging. The horizontal axis (Spatial Frequency in cycles per mm) represents the resolution, and the unit is the number of line pairs per millimeter. The image source pixel size used in the embodiment of the present application is 5.4um, and the corresponding design resolution is 93 line pairs per millimeter. The projection lens generally requires that the MTF value of each field of view is at least 0.3 in the design. In this embodiment, the MTF value of each field of view is above 0.79.

[0082] like Figure 4 As shown, the smaller the spot radius of each field of view, the better the imaging quality it represents. Generally, if the full field of view RMS is smaller than the pixel size (5.4um), it is an excellent level. In this embodiment, the full field of view RMS is less than 2.0um, which is a very excellent level.

[0083] like Figure 5-6 As shown, Figure 5 is the field curvature evaluation diagram, Figure 6 This is a distortion evaluation diagram. The ordinate represents the field of view angle of the lens. The horizontal axis of the field curvature diagram represents the field curvature value in millimeters, and the horizontal axis of the distortion diagram represents the distortion in percentage. Distortion is a very important indicator of a projection lens. This embodiment is suitable for demanding distortion usage scenarios. The system distortion of this embodiment is within 0.0005%, and the TV distortion is within 0.0002%. Both the system distortion and TV distortion are extremely small, and the objective lens can be considered to have zero distortion.

[0084] Figure 7This is a lens relative illumination diagram, where the ordinate represents relative illumination (Relative Illumination) and the abscissa represents image height in millimeters (mm). As shown in the figure, the relative illumination at the maximum image height of the lens reaches 94%, which makes the uniformity of the projection effect of the system imaging surface 7 very good.

[0085] Furthermore, when the working distance d=200 mm, the parameters of the air intervals S1 to S6 between the lenses are shown in the following table:

[0086] Table 4 Parameters of air gaps S1 to S6 between lenses when working distance d = 200 mm

[0087] S1(mm) S2(mm) S3(mm) S4(mm) S5(mm) S6(mm) 5.6 40 8 16.8 0.3 2

[0088] like Figure 8 As shown, the focal length of the lens is 11.914mm, the FOV is 60.22°, and the F / NO is 1.876.

[0089] like Fig. 9 As shown, the MTF values ​​of each field of view are all higher than 0.79 at 93lp / mm, and the resolution is extremely good.

[0090] like Fig.10 As shown, in this embodiment, the full field RMS is less than 1.7um, which is a very excellent level.

[0091] like Figure 11-12 As shown, Fig.11 is the field curvature evaluation diagram, Fig.12 This is a distortion evaluation diagram. The ordinate represents the field of view angle of the lens. The abscissa of the field curvature diagram represents the magnitude of the field curvature value, and the abscissa of the distortion diagram represents the amount of distortion. Distortion is a very important indicator of a projection lens; this embodiment is suitable for strict distortion usage scenarios. The system distortion of this embodiment is within 0.0012%, and the TV distortion is within 0.0002%. Both the system distortion and TV distortion are extremely small, and the objective lens can be considered to have zero distortion.

[0092] like Fig.13 As shown, the edge illumination reaches 94%, so that the uniformity of the projection effect of the system imaging surface 7 is very good.

[0093] When the working distance d = 300 mm, the parameters of the air intervals S1 to S6 between the lenses are shown in the following table:

[0094] Table 5 Parameters of the air intervals S1 to S6 between lenses when the working distance d = 300 mm:

[0095] S1(mm) S2(mm) S3(mm) S4(mm) S5(mm) S6(mm) 6.5 30.9 10.7 14.9 0.1 1.8

[0096] like Fig.14 As shown, the focal length of the lens is 11.859mm, the FOV is 58.28°, and the F / NO is 1.875.

[0097] like Fig.15 As shown, in this embodiment, the MTF values ​​of each field of view are all higher than 0.80 at 93lp / mm, and the resolution is extremely excellent.

[0098] like Fig.16 As shown, in this embodiment, the full field RMS is less than 1.5um, which is a very excellent level.

[0099] like Figure 17-18 As shown, Fig.17 is the field curvature evaluation diagram, Fig.18 This is a distortion evaluation diagram. The ordinate represents the field of view angle of the lens. The abscissa of the field curvature diagram represents the magnitude of the field curvature value, and the abscissa of the distortion diagram represents the amount of distortion. Distortion is a very important indicator of a projection lens; this embodiment is suitable for strict distortion usage scenarios. The system distortion of this embodiment is within 0.003%, and the TV distortion is within 0.0002%. Both the system distortion and TV distortion are extremely small, and the objective lens can be considered to have zero distortion.

[0100] like Fig.19 As shown, the edge illumination reaches 92%, so that the uniformity of the projection effect of the system imaging surface 7 is very good.

[0101] Furthermore, the MTF of the lens is greater than 0.79, which can achieve ultra-high-definition imaging; when the lens is used at different working distances, high-quality imaging can be achieved by simply changing the air spacing of each lens; the lens adopts a 0.47-inch DMD chip; the relative illumination of the lens is very high, which is conducive to improving the uniformity of the optical machine; the selected lens material has a high transmittance to light of 405nm wavelength.

[0102] Furthermore, in an embodiment, the optical lens satisfies the following conditional formula:

[0103] 1.5<|fg3 / fG1GM2|<1.55 (1)

[0104] Among them, fG3 represents the focal length of lens G3, and fg1GM2 represents the combined focal length of lenses G1 and GM2.

[0105] When condition (1) is satisfied, the objective system has a stronger ability to correct distortion and coma. When the value of |fg3 / fG1GM2| exceeds the upper limit, the ability of the first group of the objective system to correct distortion and coma will be limited; when the value of |fg3 / fG1GM2| exceeds the lower limit, the ability of the second group of the objective system to correct distortion and coma will be limited.

[0106] In an embodiment, the optical lens satisfies the following conditional formula:

[0107] 1.74 <CURV2 / CURV1<1.92 (2)

[0108] Here, CURV2 represents the curvature of the second surface of the lens G1, and CURV1 represents the curvature of the first surface of the lens G1.

[0109] When condition (2) is satisfied, the processing capability of lens G1 and the aberration correction capability of lens 1 can be reasonably balanced. When the value of CURV2 / CURV1 exceeds the lower limit, the lens will be difficult to process; when the value of CURV2 / CURV1 exceeds the upper limit, the aberration correction capability of the lens will decrease.

[0110] In an embodiment, the optical lens satisfies the following conditional formula:

[0111] CRA<1.5° (3)

[0112] Wherein, CRA represents the incident angle of the chief ray of the optical lens on the imaging plane 7 .

[0113] When condition (3) is met, the DMD chip can be well matched to achieve a good projection effect.

[0114] In an embodiment, the optical lens satisfies the following conditional formula:

[0115] 13.5° <RAID3<15° (4)

[0116] Among them, RAID3 represents the incident angle of the full-field chief light on the aperture 3 surface.

[0117] When condition (4) is satisfied, the aberration correction capabilities of the first group and the second group of the objective lens system can be reasonably balanced. When the value of RAID3 exceeds the lower limit, it is not conducive to the correction of spherical aberration and distortion of the first group; when the value of RAID3 exceeds the upper limit, it is not conducive to the correction of coma, spherical aberration and distortion of the second group.

[0118] In the implementation, the second group of objective lenses adopts a combination of G4G5 double cemented lens + aspherical lens GM6.

[0119] It is beneficial to correct the spherical aberration and coma of the system, and further enables the objective system to achieve high-quality imaging by only changing the air gap when the working distance changes; G4G double bonding is beneficial to eliminate the primary aberration of the system and reduce the tolerance sensitivity of the objective system.

[0120] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0121] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A zero-distortion ultra-high-definition lens for DLP 3D printing, characterized in that: include: A first lens group, an aperture, a second lens group, a galvanometer, a beam splitter, a protective glass and an imaging surface are arranged in sequence; The imaging surface is used to emit light, the protective glass is used to prevent dust from falling onto the imaging surface and the spectroscopic device, the galvanometer is used to adjust the pixels of the imaging, the spectroscopic device is used to split the light, the aperture is used to control the amount of light entering after the splitting, and the first group of lenses and the second group of lenses are both used to correct aberrations; The first group of lenses includes: a first lens, a second lens and a third lens, the first lens and the second lens are both lenses with negative optical power, and the third lens is a lens with positive optical power; The second group of lenses includes: a fourth lens, a fifth lens, and a sixth lens; The sixth lens is a lens with positive power, and the fourth lens and the fifth lens constitute a doublet lens with negative power; The first lens, the second lens and the third lens are all placed before the aperture stop, and the fourth lens, the fifth lens and the sixth lens are all placed after the aperture stop.

2. A zoom objective lens system for micro-projection according to claim 1, characterized in that: The first lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the galvanometer, the beam splitter and the protective glass are all made of glass.

3. The zoom objective lens system for micro-projection according to claim 1, characterized in that: The second lens and the sixth lens are both aspherical lenses.

4. The zoom objective lens system for micro-projection according to claim 1, characterized in that: The ratio of the focal length of the first group of lenses to the focal length of the zoom objective lens system is in the range of 4.18 to 4.21; the ratio of the focal length of the first lens to the focal length of the first group of lenses is in the range of -1.135 to -1.306; the ratio of the focal length of the second lens to the focal length of the first group of lenses is in the range of -0.741 to -0.736; the ratio of the focal length of the third lens to the focal length of the first group of lenses is in the range of 0.736 to 0.741; the ratio of the focal length of the second group of lenses to the focal length of the zoom objective lens system is in the range of 2.067 to 2.085, the ratio of the focal length of the doublet lens with negative optical power to the focal length of the second group of lenses is in the range of -115.982 to -115.972; the ratio of the focal length of the sixth lens to the focal length of the second group of lenses is less than 1.

157.

5. The zoom objective lens system for micro-projection according to claim 1, characterized in that: The MTF value of each field of view of the zoom objective system is greater than 0.

79.

6. The zoom objective lens system for micro-projection according to claim 1, characterized in that: The lens of the zoom objective system adopts a 0.47-inch DMD chip.

7. The zoom objective lens system for micro-projection according to claim 1, characterized in that: The first lens uses a meniscus lens.

Images