Multiband projection system

Abstract

The application discloses a multi-waveband projection system, comprising: an optical lens group and a diaphragm, the optical lens group comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens arranged in sequence along an optical axis from an object plane to an image plane. The first lens, the second lens, the fourth lens, the fifth lens, the eighth lens and the ninth lens all have positive focal power, and the third lens, the sixth lens and the seventh lens all have negative focal power. The working wavelength of the multi-waveband projection system satisfies 350nm<=lambda<=450nm, the numerical aperture satisfies 0.09<=NA<=0.12, and the field of view satisfies 20mm<=Y<=30mm. According to the multi-waveband projection system, the focal power of each lens is reasonably distributed, various aberrations are fully corrected, the multi-waveband projection system can satisfy the optical characteristics of achromatism, small distortion, small field curvature, high transmittance and the like in a light source with a wavelength of 350nm-450nm, and can match the reaction wavelength of most photosensitive materials.

Description

Technical Field

[0001] This invention relates to the field of maskless direct-write lithography technology, and in particular to a multi-band projection system. Background Technology

[0002] Direct-write lithography equipment is one of the mainstream devices used in integrated circuit manufacturing, and the projection system is the core component of this equipment. The performance of the projection system directly affects the line quality and production efficiency of the circuit board. Currently, the common operating wavelengths of projection systems in direct-write lithography equipment are in the range of 370nm-410nm. Among them, most projection systems only support a wavelength around 405nm, a few support a wavelength between 370nm and 410nm, and a very small number support a wavelength between 365nm and 415nm.

[0003] With the increasing coverage of direct-write lithography equipment in lithography processes, the increased complexity of circuit design, the increase in the types of photosensitive materials, and the greater variety of exposure light sources and wavelengths, the operating wavelengths of projection systems can no longer meet the usage requirements of most direct-write lithography equipment. There is an urgent need for projection systems that cover a wider wavelength range.

[0004] From an optical design perspective, the wider the wavelength range of a projection system, the more difficult it is to correct aberrations. Insufficient aberration correction directly affects resolution and degrades circuit board line quality, while over-correction complicates the optical structure design, increasing assembly difficulty and cost. To correct aberrations, projection systems require more lenses. For example, projection systems supporting wavelengths of 370nm-410nm typically use 8 or more lenses, while those supporting 365nm-415nm often use 10 or more. While this widens the operating wavelength range, the increased number of lenses results in relatively lower transmittance, more complex structural design, and increased assembly difficulty and efficiency. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, one object of the present invention is to provide a multi-band projection system that can match the response wavelength of most photosensitive materials, has extremely high compatibility, good imaging quality, and at the same time, the projection system has a simple structure and is easy to assemble.

[0006] A multi-band projection system according to an embodiment of the present invention includes: an optical lens group comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens arranged sequentially along the optical axis from the object plane to the image plane; the first lens, the second lens, the fourth lens, the fifth lens, the eighth lens, and the ninth lens all have positive optical power; the third lens, the sixth lens, and the seventh lens all have negative optical power; and an aperture stop located between the sixth lens and the seventh lens; wherein the multi-band projection system satisfies: 350nm≤λ≤450nm, 0.09≤NA≤0.12, 20mm≤Y≤30mm, where λ is the operating wavelength of the multi-band projection system, NA is the numerical aperture of the object side of the multi-band projection system, and Y is the linear field of view of the object side of the multi-band projection system.

[0007] According to an embodiment of the present invention, the multi-band projection system employs nine lenses and rationally allocates the optical power of each lens to fully correct various aberrations. This enables the multi-band projection system to meet optical characteristics such as achromaticity, low distortion, low field curvature, and high transmittance within a light source with a wavelength of 350nm-450nm. Furthermore, it can match the response wavelength of most photosensitive materials, exhibiting extremely high compatibility and good imaging quality. At the same time, the multi-band projection system has a simple structure and is easy to assemble.

[0008] According to some embodiments of the present invention, the first lens, the second lens, the fourth lens, and the fifth lens are all biconvex lenses; wherein, the radius of curvature of the near-object surface of the first lens is the same as the radius of curvature of the near-image surface of the first lens; the radius of curvature of the near-object surface of the second lens is smaller than the radius of curvature of the near-image surface of the second lens; the radius of curvature of the near-object surface of the fourth lens is larger than the radius of curvature of the near-image surface of the fourth lens; and the radius of curvature of the near-object surface of the fifth lens is smaller than the radius of curvature of the near-image surface of the fifth lens.

[0009] According to some embodiments of the present invention, the radius of curvature of the first lens ranges from 255mm to 275mm; the radius of curvature of the near-object surface of the second lens ranges from 60mm to 90mm, and the radius of curvature of the near-image surface of the second lens ranges from 115mm to 135mm; the radius of curvature of the near-object surface of the fourth lens ranges from 235mm to 255mm, and the radius of curvature of the near-image surface of the fourth lens ranges from 40mm to 60mm; the radius of curvature of the near-object surface of the fifth lens ranges from 25mm to 40mm, and the radius of curvature of the near-image surface of the fifth lens ranges from 320mm to 340mm.

[0010] According to some embodiments of the present invention, both the third lens and the seventh lens are biconcave lenses; wherein, the radius of curvature of the near-object surface of the third lens is smaller than the radius of curvature of the near-image surface of the third lens, the radius of curvature of the near-object surface of the third lens ranges from 55mm to 75mm, and the radius of curvature of the near-image surface of the third lens ranges from 65mm to 85mm; the radius of curvature of the near-object surface of the seventh lens is smaller than the radius of curvature of the near-image surface of the seventh lens, the radius of curvature of the near-object surface of the seventh lens ranges from 15mm to 35mm, and the radius of curvature of the near-image surface of the seventh lens ranges from 95mm to 115mm.

[0011] According to some embodiments of the present invention, the sixth lens is a plano-concave lens, and the ninth lens is a plano-convex lens. The radius of curvature of the near-object surface of the sixth lens is infinite, and the radius of curvature of the near-image surface of the sixth lens ranges from 80mm to 100mm; the radius of curvature of the near-object surface of the ninth lens is 105mm to 125mm, and the radius of curvature of the near-image surface of the ninth lens is infinite.

[0012] According to some embodiments of the present invention, the eighth lens is a meniscus lens, and the radius of curvature of the near-object surface of the eighth lens is greater than the radius of curvature of the near-image surface of the eighth lens. The radius of curvature of the near-object surface of the eighth lens ranges from 175mm to 195mm, and the radius of curvature of the near-image surface of the eighth lens ranges from 35mm to 55mm.

[0013] According to some embodiments of the present invention, the refractive index Nd and Abbe number Vd of the first lens satisfy: 1.65≤Nd≤1.80, 40≤Vd≤50; the refractive index Nd and Abbe number Vd of the second lens satisfy: 1.45≤Nd≤1.50, 75≤Vd≤85; the refractive index Nd and Abbe number Vd of the third lens satisfy: 1.65≤Nd≤1.75, 40≤Vd≤55; the refractive index Nd and Abbe number Vd of the fourth lens satisfy: 1.45≤Nd≤1.50, 75≤Vd≤85; the refractive index Nd and Abbe number Vd of the fifth lens satisfy: 1.65≤Nd≤1.75, 40≤Vd≤55; the refractive index Nd and Abbe number Vd of the fifth lens satisfy: 1.45≤Nd≤1.50, 75≤Vd≤85; the refractive index Nd and Abbe number Vd of the fifth lens satisfy: 1.65≤Nd≤1.80, 40≤Vd≤55; the refractive index Nd and Abbe number Vd of the fourth lens satisfy: 1.45≤Nd≤1.50, 75≤Vd≤85; the refractive index Nd and Abbe number Vd of the fifth lens satisfy: 1.65≤Nd≤1.80, 40≤Vd≤5 ... third lens satisfy: 1.65≤Nd≤1.80, 40≤Vd≤55; the refractive index Nd and Abbe number Vd of the fourth lens satisfy: 1.45≤Nd≤1 The refractive index Nd and Abbe number Vd of the sixth lens satisfy: 1.45≤Nd≤1.50, 75≤Vd≤85; the refractive index Nd and Abbe number Vd of the seventh lens satisfy: 1.65≤Nd≤1.75, 40≤Vd≤55; the refractive index Nd and Abbe number Vd of the eighth lens satisfy: 1.55≤Nd≤1.70, 30≤Vd≤40; the refractive index Nd and Abbe number Vd of the ninth lens satisfy: 1.60≤Nd≤1.75, 45≤Vd≤55.

[0014] According to some embodiments of the present invention, the multi-band projection system is a dual telecentric structure, the telecentricity of the object side of the multi-band projection system is T1, and the telecentricity of the image side of the multi-band projection system is T2, wherein T1 and T2 respectively satisfy: T1 < 0.1°, T2 < 0.15°.

[0015] According to some embodiments of the present invention, the minimum distance between the object plane of the multi-band projection system and the first lens is in the range of 70mm-85mm, and the minimum distance between the image plane of the multi-band projection system and the ninth lens is in the range of 80mm-100mm.

[0016] According to some embodiments of the present invention, the surface shape of the first lens to the ninth lens is spherical.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0019] Figure 1 This is a schematic diagram of the structure of a multi-band projection system according to an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the optical path of a multi-band projection system according to an embodiment of the present invention;

[0021] Figure 3 This is an MTF (Modulation Transfer Function) curve of a multi-band projection system according to an embodiment of the present invention.

[0022] Figure 4 This is a dot plot of a multi-band projection system according to an embodiment of the present invention;

[0023] Figure 5 This is a transverse chromatic aberration diagram of a multi-band projection system according to an embodiment of the present invention;

[0024] Figure 6 This is a field curvature and distortion diagram of a multi-band projection system according to an embodiment of the present invention.

[0025] Figure label:

[0026] 100: Multi-band projection system;

[0027] 1: Object plane; 2: Protective glass; 3: Flat glass; 4: First lens group; 41: First lens; 42: Second lens; 43: Third lens; 44: Fourth lens; 45: Fifth lens; 46: Sixth lens; 5: Aperture stop; 6: Second lens group; 61: Seventh lens; 62: Eighth lens; 63: Ninth lens; 7: Image plane. Detailed Implementation

[0028] The following is for reference. Figures 1-6 A multi-band projection system 100 according to an embodiment of the present invention is described.

[0029] like Figures 1-6 As shown, the multi-band projection system 100 according to an embodiment of the present invention includes an optical lens group and an aperture 5.

[0030] Specifically, the optical lens group includes a first lens 41, a second lens 42, a third lens 43, a fourth lens 44, a fifth lens 45, a sixth lens 46, a seventh lens 61, an eighth lens 62, and a ninth lens 63, arranged sequentially along the optical axis from the object plane 1 to the image plane 7. The first lens 41, second lens 42, fourth lens 44, fifth lens 45, eighth lens 62, and ninth lens 63 all have positive optical power. The third lens 43, sixth lens 46, and seventh lens 61 all have negative optical power. The aperture stop 5 is located between the sixth lens 46 and the seventh lens 61.

[0031] For example, in Figure 1 and Figure 2 In the example, the first lens 41, the second lens 42, the third lens 43, the fourth lens 44, the fifth lens 45, the sixth lens 46, the seventh lens 61, the eighth lens 62, and the ninth lens 63 are arranged alternately, with the first lens 41 located closer to the object plane 1 and the ninth lens 63 located closer to the image plane 7. The first lens 41, the second lens 42, the third lens 43, the fourth lens 44, the fifth lens 45, and the sixth lens 46 located between the object plane 1 and the aperture 5 constitute the first lens group 4, and the seventh lens 61, the eighth lens 62, and the ninth lens 63 located between the aperture 5 and the image plane 7 constitute the second lens group 6. The beam is corrected multiple times by a combination of lenses, namely the first lens 41, the second lens 42, the third lens 43, the fourth lens 44, the fifth lens 45, the sixth lens 46, the seventh lens 61, the eighth lens 62 and the ninth lens 63, to ensure the rationality of the system aberration distribution and balance the lens sensitivity. This allows the multi-band projection system 100 to use a wider range of light sources, be compatible with more photosensitive materials, have a simple structure and good imaging quality.

[0032] It should be explained that optical power refers to the difference between the convergence of the image-side beam and the convergence of the object-side beam. It is a measure of the ability of an optical system to converge or diverge beams, and is used to characterize the ability of the multi-band projection system 100 to deflect light. That is, the larger the optical power value, the greater the degree of light deflection by the multi-band projection system 100. Specifically, when the optical power is positive, the light deflection is converging; when the optical power is negative, the light deflection is diverging. The first lens 41, second lens 42, fourth lens 44, fifth lens 45, eighth lens 62, and ninth lens 63 in the multi-band projection system 100 convergently deflect the beam, while the third lens 43, sixth lens 46, and seventh lens 61 diverge the beam. This facilitates aberration correction in the multi-band projection system 100, ensures the imaging quality of the multi-band projection system 100, and allows the multi-band projection system 100 to use a wider wavelength light source.

[0033] In addition, by rationally allocating the optical power of the first lens 41, the second lens 42, the third lens 43, the fourth lens 44, the fifth lens 45, the sixth lens 46, the seventh lens 61, the eighth lens 62 and the ninth lens 63, various aberrations are fully corrected, making the structure of the multi-band projection system 100 simple and easy to assemble.

[0034] By placing the aperture stop 5 between the sixth lens 46 and the seventh lens 61, the influence of stray light on the imaging of the multi-band projection system 100 can be eliminated, which is beneficial to improving the imaging quality.

[0035] The multi-band projection system 100 satisfies the following: 350nm≤λ≤450nm, 0.09≤NA≤0.12, 20mm≤Y≤30mm, where λ is the operating wavelength of the multi-band projection system 100, NA is the numerical aperture of the object side of the multi-band projection system 100, and Y is the line field of view of the object side of the multi-band projection system 100.

[0036] The multi-band projection system 100 operates at a wavelength of 350nm≤λ≤450nm. Compared with traditional projection systems, the multi-band projection system 100 can match the response wavelength of most photosensitive materials, exhibiting extremely high compatibility. Furthermore, the multi-band projection system 100 uses fewer lenses, has a simpler structure, and a reasonable aberration distribution, enabling it to meet optical characteristics such as achromaticity, low distortion, low field curvature, and high transmittance within this wavelength range.

[0037] It should be noted that numerical aperture (NA) measures the angular range of light that a multi-band projection system 100 can collect. In other words, numerical aperture represents the size of the lens's light-gathering cone angle. According to the resolution calculation formula σ = Kλ / NA (where σ is the minimum resolving distance; K is the process factor; λ is the wavelength of light; and NA is the numerical aperture of the objective lens), it can be seen that the larger the NA, the smaller the minimum resolving distance σ, and thus the higher the resolution and the stronger the resolving power of the multi-band projection system 100. Therefore, by setting the object-side numerical aperture of the multi-band projection system 100 to 0.09 ≤ NA ≤ 0.12, the depth of focus and design / assembly difficulty of the multi-band projection system 100 can be balanced.

[0038] Specifically, when NA < 0.09, the angular range of light that the multi-band projection system 100 can collect is too small. For LD+LED coupled light sources, this small divergence angle reduces the energy utilization rate of the multi-band projection system 100, thus requiring a higher power light source and increasing costs. When NA > 0.12, the angular range of light that the multi-band projection system 100 can collect is too large, increasing the design difficulty of the multi-band projection system 100 and reducing image quality. Therefore, by setting the object-side numerical aperture of the multi-band projection system 100 to 0.09 ≤ NA ≤ 0.12, the design of the multi-band projection system 100 is made more reasonable, improving image quality while being applicable to various types of light sources and exhibiting extremely high compatibility.

[0039] According to an embodiment of the present invention, the multi-band projection system 100 employs nine lenses and rationally allocates the optical power of each lens to fully correct various aberrations. This enables the multi-band projection system 100 to meet optical characteristics such as achromaticity, low distortion, low field curvature, and high transmittance within a light source with a wavelength of 350nm-450nm. Furthermore, it can match the response wavelength of most photosensitive materials, exhibiting extremely high compatibility and good imaging quality. At the same time, the multi-band projection system 100 has a simple structure and is easy to assemble.

[0040] According to some embodiments of the present invention, with reference to Figure 1 and Figure 2 Lenses 41, 42, 44, and 45 are all biconvex lenses. Specifically, the radius of curvature of the near-object surface of lens 41 is the same as the radius of curvature of its near-image surface. The radius of curvature of the near-object surface of lens 42 is smaller than that of its near-image surface. The radius of curvature of the near-object surface of lens 44 is larger than that of its near-image surface. The radius of curvature of the near-object surface of lens 45 is smaller than that of its near-image surface.

[0041] A biconvex lens is thicker in the middle and thinner at the edges, and has the function of converging light rays; it is also called a converging lens. By properly setting the curvature radii of the near-object plane and the near-image plane of the first lens 41, the second lens 42, the fourth lens 44, and the fifth lens 45, the first lens 41, the second lens 42, the fourth lens 44, and the fifth lens 45 can effectively converge the light beam.

[0042] Furthermore, the radius of curvature of the near-object surface of the first lens 41 ranges from 255mm to 275mm. The radius of curvature of the near-object surface of the second lens 42 ranges from 60mm to 90mm, and the radius of curvature of the near-image surface of the second lens 42 ranges from 115mm to 135mm. The radius of curvature of the near-object surface of the fourth lens 44 ranges from 235mm to 255mm, and the radius of curvature of the near-image surface of the fourth lens 44 ranges from 40mm to 60mm. The radius of curvature of the near-object surface of the fifth lens 45 ranges from 25mm to 40mm, and the radius of curvature of the near-image surface of the fifth lens 45 ranges from 320mm to 340mm. Therefore, the first lens 41, the second lens 42, the fourth lens 44 and the fifth lens 45 can converge the passing light beam to different degrees, thereby effectively correcting the light beam of the multi-band projection system 100 multiple times, so that the multi-band projection system 100 can use a wider range of light sources and be compatible with more types of photosensitive materials.

[0043] According to some embodiments of the present invention, with reference to Figure 1 and Figure 2 Both the third lens 43 and the seventh lens 61 are biconcave lenses. Specifically, the radius of curvature of the near-object surface of the third lens 43 is smaller than the radius of curvature of its near-image surface. The radius of curvature of the near-object surface of the third lens 43 ranges from 55mm to 75mm, while the radius of curvature of its near-image surface ranges from 65mm to 85mm. Similarly, the radius of curvature of the near-object surface of the seventh lens 61 is smaller than the radius of curvature of its near-image surface. The radius of curvature of the near-object surface of the seventh lens 61 ranges from 15mm to 35mm, while the radius of curvature of its near-image surface ranges from 95mm to 115mm.

[0044] The biconcave lens is thin in the middle and thick at the edges, and is concave in shape, which has a diverging effect. Furthermore, the third lens 43 and the seventh lens 61 have negative optical power.

[0045] According to some embodiments of the present invention, such as Figure 1 and Figure 2As shown, the sixth lens 46 is a plano-concave lens, and the ninth lens 63 is a plano-convex lens. The near-object surface of the sixth lens 46 is flat, and its radius of curvature is infinite. The radius of curvature of its near-image surface ranges from 80mm to 100mm. The near-image surface of the ninth lens 63 is flat, and its radius of curvature is 105mm to 125mm. The radius of curvature of its near-image surface is infinite.

[0046] The near-object surface of the sixth lens 46 is flat, and the near-image surface of the sixth lens 46 is concave, with the concave surface facing the aperture stop. It has negative optical power, and the concave surface of the sixth lens facing the aperture stop can reduce off-axis aberrations. The near-image surface of the ninth lens 63 is flat, and the near-object surface of the ninth lens 63 is convex, with positive optical power. It is used to converge the beam from the eighth lens 62 to magnify the image.

[0047] According to some embodiments of the present invention, with reference to Figure 1 and Figure 2 The eighth lens 62 is a meniscus lens. The radius of curvature of the near-object surface of the eighth lens 62 is greater than the radius of curvature of the near-image surface of the eighth lens 62. Specifically, the radius of curvature of the near-object surface of the eighth lens 62 ranges from 175mm to 195mm, while the radius of curvature of the near-image surface ranges from 35mm to 55mm. The meniscus lens is beneficial for correcting aberrations such as field curvature and can make the light path smoother, thereby giving the multi-band projection system 100 higher imaging quality.

[0048] like Figure 1 As shown, a meniscus lens can also be called a concave-convex lens. The near-image surface of the eighth lens 62 is convex, and the near-object surface of the eighth lens 62 is concave. Since the curvature of the near-image surface is greater than the curvature of the near-object surface, the eighth lens 62 has positive optical power.

[0049] According to some specific embodiments of the present invention, the refractive index Nd and Abbe number Vd of the first lens 41 satisfy: 1.65≤Nd≤1.80, 40≤Vd≤50;

[0050] The refractive index Nd and Abbe number Vd of the second lens 42 satisfy: 1.45≤Nd≤1.50, 75≤Vd≤85;

[0051] The refractive index Nd and Abbe number Vd of the third lens 43 satisfy: 1.65≤Nd≤1.75, 40≤Vd≤55;

[0052] The refractive index Nd and Abbe number Vd of the fourth lens 44 satisfy: 1.45≤Nd≤1.50, 75≤Vd≤85;

[0053] The refractive index Nd and Abbe number Vd of the fifth lens 45 satisfy: 1.45≤Nd≤1.50, 75≤Vd≤85;

[0054] The refractive index Nd and Abbe number Vd of the sixth lens 46 satisfy: 1.65≤Nd≤1.75, 40≤Vd≤55;

[0055] The refractive index Nd and Abbe number Vd of the seventh lens 61 satisfy: 1.55≤Nd≤1.70, 30≤Vd≤40;

[0056] The refractive index Nd and Abbe number Vd of the eighth lens 62 satisfy: 1.55≤Nd≤1.70, 30≤Vd≤40;

[0057] The refractive index Nd and Abbe number Vd of the ninth lens 63 satisfy: 1.60≤Nd≤1.75, 45≤Vd≤55.

[0058] This configuration improves the design rationality of the nine lenses, which helps to ensure the imaging quality of the multi-band projection system 100 and makes it easier to control the aberrations of the multi-band projection system 100, especially the correction of magnification chromatic aberration, that is, the correction of the change in the refractive index of the material caused by the change in wavelength, which leads to the change in the magnification of the multi-band projection system 100.

[0059] According to some specific embodiments of the present invention, the multi-band projection system 100 has a dual telecentric structure. The telecentricity of the object side of the multi-band projection system 100 is T1, and the telecentricity of the image side of the multi-band projection system 100 is T2, wherein T1 and T2 satisfy: T1 < 0.1°, T2 < 0.15°, respectively. The dual telecentric structure has the ability to achieve high exposure accuracy. The magnification of the multi-band projection system 100 using the dual telecentric structure does not change with distance, and it has a greater depth of focus.

[0060] Telecentrism refers to the angle by which the principal ray deviates from the optical axis. The smaller the angle, the better the telecentrism. When T1 ≥ 0.1° and / or T2 ≥ 0.15°, both the object-side telecentrism and the image-side telecentrism of the multi-band projection system 100 are too large, resulting in significant changes in the magnification of the multi-band projection system 100. Setting the object-side telecentrism and the image-side telecentrism of the multi-band projection system 100 to T1 < 0.1° and T2 < 0.15°, respectively, helps to reduce magnification error and increase the depth of focus range.

[0061] According to some specific embodiments of the present invention, the minimum distance between the object plane 1 of the multi-band projection system 100 and the first lens 41 is in the range of 70mm-85mm, and the minimum distance between the image plane 7 of the multi-band projection system 100 and the ninth lens 63 is in the range of 80mm-100mm.

[0062] In some optional embodiments, the surface shape of the first lens 41 to the ninth lens 63 is spherical. Therefore, by combining positive and negative optical powers, various aberrations can be corrected, achieving high imaging quality, and with high manufacturability and assemblability. It is understood that when the radius of curvature of a sphere approaches infinity, the sphere can infinitely approach a plane.

[0063] For example, the multi-band projection system 100 may also include a protective glass 2 and a flat glass 3. Along the optical axis from the object side to the image side, the following are arranged sequentially: object plane 1, protective glass 2, flat glass 3, first lens 41, second lens 42, third lens 43, fourth lens 44, fifth lens 45, sixth lens 46, aperture 5, seventh lens 61, eighth lens 62, and ninth lens 63, and image plane 7. The protective glass 2 and flat glass 3 may both have planar surfaces on both sides in the direction from image plane 7 to object plane 1. Neither has optical power and does not participate in aberration correction. The flat glass 3 replaces the TIR (Total Internal Reflection) prism.

[0064] The following describes a specific embodiment. The parameters of the multi-band projection system 100 are shown in Table 1 below:

[0065] Table 1

[0066]

[0067]

[0068] Reference Figure 3 , Figure 3 To illustrate the MTF (Modulation Transfer Function) plot of the multi-band projection system 100 of this invention, simulated using the optical design software "ZEMAX", the following diagram is provided. Figure 3 It can be seen that it has basically reached the diffraction limit, and the imaging quality is relatively good.

[0069] Reference Figure 4 It can be seen that, within the full field of view, in the 350nm-450nm wavelength range, the geometric diameter and root mean square diameter of its dot pattern are both within the Airy disk, meeting application requirements. Here, "Airy disk" refers to the light spot formed at the focal point due to diffraction when a point light source is imaged through an ideal lens.

[0070] Reference Figure 5 , Figure 5 The vertical axis chromatic aberration diagram shows the magnitude of chromatic aberration on the horizontal axis and the field of view on the vertical axis. Different color curves correspond to different chromatic aberration magnitudes in different wavelength bands. From... Figure 5It can be seen that the magnification chromatic aberration correction is good. In the 350nm-450nm band, the magnification chromatic aberration is less than 0.9μm, and in the 405nm band, the magnification chromatic aberration is less than 0.4μm. Furthermore, chromatic aberration is achieved in the middle band at 0.7 and 0.9 field of view.

[0071] Reference Figure 6 , Figure 6 The field curvature plot shows the field curvature on the horizontal axis and the field of view on the vertical axis. Different colored curves correspond to different field curvature magnitudes in different wavelength bands. From Figure 6 It can be seen that, in the full field of view, within the 350nm-450nm band, the field curvature is less than 40μm.

[0072] Reference Figure 6 , Figure 6 The distortion graph shows the percentage of distortion on the horizontal axis and the field of view on the vertical axis. Different colored curves correspond to different distortion levels in different wavelength bands. Figure 6 As can be seen, the distortion is 0.02%, and the absolute line distortion is less than 1 μm.

[0073] Other configurations and operations of the multi-band projection system 100 according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0074] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "inner", "outer", "axial", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0075] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0076] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0077] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A multi-band projection system, characterized in that, include: An optical lens group, comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens arranged sequentially along the optical axis from the object plane to the image plane; The first lens, the second lens, the fourth lens, the fifth lens, the eighth lens, and the ninth lens all have positive optical power; The third lens, the sixth lens, and the seventh lens all have negative optical power; An aperture stop, located between the sixth lens and the seventh lens; The multi-band projection system satisfies the following: 350nm≤λ≤450nm, 0.09≤NA≤0.12, 20mm≤Y≤30mm, where λ is the operating wavelength of the multi-band projection system, NA is the numerical aperture of the object side of the multi-band projection system, and Y is the linear field of view of the object side of the multi-band projection system. The first lens, the second lens, the fourth lens, and the fifth lens are all biconvex lenses; Wherein, the radius of curvature of the near-object surface of the first lens is the same as the radius of curvature of the near-image surface of the first lens; The radius of curvature of the near-object surface of the second lens is smaller than the radius of curvature of the near-image surface of the second lens; The radius of curvature of the near-object surface of the fourth lens is greater than the radius of curvature of the near-image surface of the fourth lens. The radius of curvature of the near-object surface of the fifth lens is smaller than the radius of curvature of the near-image surface of the fifth lens; Both the third lens and the seventh lens are biconcave lenses; Wherein, the radius of curvature of the near-object surface of the third lens is smaller than the radius of curvature of the near-image surface of the third lens, the radius of curvature of the near-object surface of the third lens is in the range of 55mm-75mm, and the radius of curvature of the near-image surface of the third lens is in the range of 65mm-85mm. The radius of curvature of the near-object surface of the seventh lens is smaller than the radius of curvature of the near-image surface of the seventh lens. The radius of curvature of the near-object surface of the seventh lens ranges from 15mm to 35mm, and the radius of curvature of the near-image surface of the seventh lens ranges from 95mm to 115mm. The sixth lens is a plano-concave lens; the ninth lens is a plano-convex lens; The radius of curvature of the near-object surface of the sixth lens is infinite, and the radius of curvature of the near-image surface of the sixth lens ranges from 80mm to 100mm. The radius of curvature of the near-object surface of the ninth lens is 105mm-125mm, and the radius of curvature of the near-image surface of the ninth lens is infinite. The eighth lens is a meniscus lens. The radius of curvature of the near-object surface of the eighth lens is greater than the radius of curvature of the near-image surface of the eighth lens. The radius of curvature of the near-object surface of the eighth lens ranges from 175mm to 195mm, and the radius of curvature of the near-image surface of the eighth lens ranges from 35mm to 55mm.

2. The multi-band projection system according to claim 1, characterized in that, The radius of curvature of the first lens ranges from 255mm to 275mm; The radius of curvature of the near-object surface of the second lens ranges from 60mm to 90mm, and the radius of curvature of the near-image surface of the second lens ranges from 115mm to 135mm. The radius of curvature of the near-object surface of the fourth lens ranges from 235mm to 255mm, and the radius of curvature of the near-image surface of the fourth lens ranges from 40mm to 60mm. The radius of curvature of the near-object surface of the fifth lens ranges from 25mm to 40mm, and the radius of curvature of the near-image surface of the fifth lens ranges from 320mm to 340mm.

3. The multi-band projection system according to claim 1, characterized in that, The refractive index Nd and Abbe number Vd of the first lens satisfy: 1.65≤Nd≤1.80, 40≤Vd≤50; The refractive index Nd and Abbe number Vd of the second lens satisfy: 1.45≤Nd≤1.50, 75≤Vd≤85; The refractive index Nd and Abbe number Vd of the third lens satisfy: 1.65≤Nd≤1.75, 40≤Vd≤55; The refractive index Nd and Abbe number Vd of the fourth lens satisfy: 1.45≤Nd≤1.50, 75≤Vd≤85; The refractive index Nd and Abbe number Vd of the fifth lens satisfy: 1.45≤Nd≤1.50, 75≤Vd≤85; The refractive index Nd and Abbe number Vd of the sixth lens satisfy: 1.65≤Nd≤1.75, 40≤Vd≤55; The refractive index Nd and Abbe number Vd of the seventh lens satisfy: 1.55≤Nd≤1.70, 30≤Vd≤40; The refractive index Nd and Abbe number Vd of the eighth lens satisfy: 1.55≤Nd≤1.70, 30≤Vd≤40; The refractive index Nd and Abbe number Vd of the ninth lens satisfy: 1.60≤Nd≤1.75, 45≤Vd≤55.

4. The multi-band projection system according to claim 1, characterized in that, The multi-band projection system is a dual telecentric structure. The telecentricity of the object side of the multi-band projection system is T1, and the telecentricity of the image side of the multi-band projection system is T2. T1 and T2 satisfy the following conditions: T1 < 0.1︒, T2 < 0.15︒.

5. The multi-band projection system according to claim 1, characterized in that, The minimum distance between the object plane of the multi-band projection system and the first lens ranges from 70mm to 85mm, and the minimum distance between the image plane of the multi-band projection system and the ninth lens ranges from 80mm to 100mm.

6. The multi-band projection system according to any one of claims 1-5, characterized in that, The surface shape of the first lens to the ninth lens is spherical.

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