A zoom projection lens and imaging device

Abstract

This invention relates to the field of optics, specifically to a zoom projection lens and an imaging device. The zoom projection lens, from the object plane side to the image plane side, consists of a negative optical power focusing lens group, a positive optical power first zoom lens group, a positive optical power second zoom lens group, a positive optical power third zoom lens group, a negative optical power fourth zoom lens group, a positive optical power fifth zoom lens group, a positive optical power fixed lens group, and a beam splitter. The zoom projection lens satisfies the following conditions: 1.5 < ft / fw < 1.8; 1.5 < fno < 2.2; where fw is the focal length of the zoom projection lens in its wide-angle state, ft is the focal length of the zoom projection lens in its telephoto state, and fno is the aperture number of the zoom projection lens. This invention achieves a zoom projection lens with a small magnification and a large aperture, while simultaneously miniaturizing the zoom projection lens by reducing the number of lenses within the zoom lens group.

Description

Technical Field

[0001] This invention relates to the field of optics, specifically to a zoom projection lens and an imaging device. Background Technology

[0002] A zoom lens is a camera lens that can change its focal length within a certain range, thereby obtaining different widths of field of view, different image sizes, and different ranges of scenery. A zoom lens can change the shooting range by changing the focal length without changing the shooting distance, which is very beneficial for image composition. Since a zoom lens can perform the function of several prime lenses, it not only reduces the amount of photography equipment needed when traveling but also saves time changing lenses.

[0003] Currently, projection lenses typically use zoom to expand their application scenarios and resolution. However, existing projection lenses usually have a large focal length, but due to aperture limitations, some large-aperture projection lenses are still bulky, inconvenient to carry, and have relatively low resolution. Summary of the Invention

[0004] This invention addresses existing technical problems by providing a zoom projection lens. By limiting the parameters and structure described above, a zoom projection lens with a small magnification and large aperture is achieved. At the same time, by reducing the number of lenses in the zoom lens group, the zoom projection lens is miniaturized.

[0005] The technical solution provided by this invention is as follows:

[0006] A zoom projection lens, comprising, from the object plane side to the image plane side, a focusing lens group with negative optical power, a first zoom lens group with positive optical power, a second zoom lens group with positive optical power, a third zoom lens group with positive optical power, a fourth zoom lens group with negative optical power, a fifth zoom lens group with positive optical power, a fixed lens group with positive optical power, and a beam splitter.

[0007] The first zoom lens group is a single zoom lens with positive optical power;

[0008] The second zoom lens group consists of a second zoom lens with positive optical power and a third zoom lens with negative optical power, arranged sequentially from the object plane side to the image plane side, and the second zoom lens and the third zoom lens are cemented together.

[0009] The third zoom lens group is a fourth zoom lens with positive optical power;

[0010] The fourth zoom lens group is a fifth zoom lens with negative optical power;

[0011] The fixed lens group is a first fixed lens with positive optical power;

[0012] The zoom projection lens satisfies the following condition:

[0013] 1.5 < ft / fw < 1.8;

[0014] 1.5 < fno < 2.2;

[0015] Where fw is the focal length of the zoom projection lens in wide-angle mode, ft is the focal length of the zoom projection lens in telephoto mode, and fno is the aperture number of the zoom projection lens.

[0016] In this technical solution, by limiting the above parameters and structure, a zoom projection lens with small magnification and large aperture is realized. At the same time, by reducing the number of lenses in the zoom lens group, the zoom projection lens is miniaturized.

[0017] Preferably, the focusing lens group consists of a first focusing lens with negative optical power, a second focusing lens with negative optical power, and a third focusing lens with negative optical power, arranged sequentially from the object plane side to the image plane side.

[0018] Preferably, the fifth zoom lens is composed of a sixth zoom lens with positive optical power, a seventh zoom lens with negative optical power, an eighth zoom lens with positive optical power, a ninth zoom lens with negative optical power, a tenth zoom lens with positive optical power, and an eleventh zoom lens with positive optical power, from the object plane side to the image plane side. The seventh and eighth zoom lenses are cemented together, and the ninth and tenth zoom lenses are cemented together.

[0019] Preferably, all lenses in the first zoom lens group to the fixed lens group are spherical lenses.

[0020] In this technical solution, the cost of zoom projection lenses is reduced by using a large number of spherical lenses.

[0021] Preferably, the zoom projection lens satisfies the following condition:

[0022] -1.2 < FG1 / fw < -1;

[0023] Wherein, FG1 is the focal length of the focusing lens group.

[0024] In this technical solution, by limiting the focal length of the focusing lens group, stable correction of the rear lens group is achieved, thereby reducing aberrations and coma of the zoom projection lens.

[0025] Preferably, the zoom projection lens satisfies the following condition:

[0026] 1.5 < XG4 / fw < 2;

[0027] Wherein, XG4 is the moving distance of the third zoom lens group.

[0028] In this technical solution, by limiting the moving distance of the third zoom lens group, zoom projection focusing within a certain range is achieved, while avoiding the possibility of the zoom lens group being too large, thus realizing the miniaturization of the zoom projection lens.

[0029] Preferably, the zoom projection lens satisfies the following condition:

[0030] 3 < FG3 / fw < 5;

[0031] Wherein, FG3 is the focal length of the second zoom lens group.

[0032] In this technical solution, by limiting the focal length of the second zoom group, the receiving efficiency of the third zoom lens group in receiving light from the second zoom lens group is increased, thereby increasing the resolution of the zoom projection lens.

[0033] Preferably, the zoom projection lens satisfies the following condition:

[0034] |Rb12| > 200mm;

[0035] Wherein, Rb12 is the radius of curvature of the curved surface of the first fixed lens near the image plane.

[0036] In this technical solution, by limiting the curvature radius of the first fixed lens, the light dissipation from the first fixed lens to the beam splitter is reduced, thereby increasing the brightness of the zoom projection lens.

[0037] One of the objectives of this invention is to provide an imaging device, comprising: a zoom projection lens; and an imaging element configured to receive an image formed by the zoom projection lens.

[0038] Compared with the prior art, the zoom projection lens and imaging device provided by the present invention have the following beneficial effects:

[0039] 1. By limiting the parameters and structure mentioned above, a zoom projection lens with a small magnification and a large aperture was achieved. At the same time, by reducing the number of lenses in the zoom lens group, the zoom projection lens was miniaturized.

[0040] 2. By limiting the moving distance of the third zoom lens group, zoom projection can be focused within a certain range, while avoiding the possibility of the zoom lens group being too large, thus achieving miniaturization of the zoom projection lens.

[0041] 3. By limiting the curvature radius of the first fixed lens, the light dissipation from the first fixed lens to the beam splitter is reduced, thereby increasing the brightness of the zoom projection lens. Attached Figure Description

[0042] The preferred embodiments will now be described in a clear and easy-to-understand manner, with reference to the accompanying drawings, to further explain the above-mentioned characteristics, technical features, advantages, and implementation methods of a zoom projection lens and imaging device.

[0043] Figure 1 This is a schematic diagram of the structure of a zoom projection lens according to the present invention;

[0044] Figure 2 This invention provides a coma diagram of a zoom projection lens in telephoto mode.

[0045] Figure 3 This is an aberration diagram of a zoom projection lens in telephoto mode according to the present invention;

[0046] Figure 4 This invention relates to a coma diagram of a zoom projection lens in a wide-angle state.

[0047] Figure 5 This is an aberration diagram of a zoom projection lens in a wide-angle state according to the present invention;

[0048] Figure 6 This is a schematic diagram of the structure of a zoom projection lens according to the present invention;

[0049] Figure 7 This invention provides a coma diagram of a zoom projection lens in telephoto mode.

[0050] Figure 8 This is an aberration diagram of a zoom projection lens in telephoto mode according to the present invention;

[0051] Figure 9 This invention relates to a coma diagram of a zoom projection lens in a wide-angle state.

[0052] Figure 10 This is an aberration diagram of a zoom projection lens in wide-angle mode according to the present invention.

[0053] Explanation of reference numerals: G1, Focusing lens group; G2, First zoom lens group; G3, Second zoom lens group; G4, Third zoom lens group; G5, Fourth zoom lens group; G6, Fifth zoom lens group; G7, Fixed lens group; G8, Auxiliary component; a1, First focusing lens; a2, Second focusing lens; a3, Third focusing lens; b1, First fixed lens; c1, First zoom lens; c2, Second zoom lens; c3, Third zoom lens; c4, Fourth zoom lens; c5, Fifth zoom lens; c6, Sixth zoom lens; c7, Seventh zoom lens; c8, Eighth zoom lens; c9, Ninth zoom lens; c10, Tenth zoom lens; c11, Eleventh zoom lens; STO, Aperture stop; P, Beam splitter prism. Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] To keep the drawings concise, each figure only schematically shows the parts relevant to the invention, and these do not represent the actual structure of the product. Furthermore, to facilitate understanding, in some figures, only one of components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0056] Example 1

[0057] like Figure 1 and Figure 6 As shown, a zoom projection lens is composed of, from the object plane side to the image plane side, a focusing lens group G1 with negative optical power, a first zoom lens group G2 with positive optical power, a second zoom lens group G3 with positive optical power, a third zoom lens group G4 with positive optical power, a fourth zoom lens group G5 with negative optical power, a fifth zoom lens group G6 with positive optical power, a fixed lens group G7 with positive optical power, and a beam splitter P.

[0058] The first zoom lens group G2 is a positive optical power first zoom lens c1;

[0059] The second zoom lens group G3 consists of a second zoom lens c2 with positive optical power and a third zoom lens c3 with negative optical power, arranged sequentially from the object plane side to the image plane side. The second zoom lens c2 and the third zoom lens c3 are cemented together.

[0060] The third zoom lens group G4 is a fourth zoom lens c4 with positive optical power;

[0061] The fourth zoom lens group G5 is a fifth zoom lens c5 with negative optical power;

[0062] The fixed lens group G7 is a first fixed lens b1 with positive optical power;

[0063] The zoom projection lens satisfies the following condition:

[0064] 1.5 < ft / fw < 1.8;

[0065] 1.5 < fno < 2.2;

[0066] Where fw is the focal length of the zoom projection lens in wide-angle mode, ft is the focal length of the zoom projection lens in telephoto mode, and fno is the aperture number of the zoom projection lens.

[0067] In this embodiment, by limiting the parameters and structure described above, a zoom projection lens with a small magnification and a large aperture is realized. At the same time, by reducing the number of lenses in the zoom lens group, the zoom projection lens is miniaturized.

[0068] The focusing lens group G1 consists of a first focusing lens a1 with negative optical power, a second focusing lens a2 with negative optical power, and a third focusing lens a3 with negative optical power, arranged sequentially from the object plane side to the image plane side.

[0069] The fifth zoom lens group G6 consists of, from the object plane side to the image plane side, a sixth zoom lens c6 with positive optical power, a seventh zoom lens c7 with negative optical power, an eighth zoom lens c8 with positive optical power, a ninth zoom lens c9 with negative optical power, a tenth zoom lens c10 with positive optical power, and an eleventh zoom lens c11 with positive optical power. The seventh zoom lens c7 and the eighth zoom lens c8 are cemented together, and the ninth zoom lens c9 and the tenth zoom lens c10 are cemented together.

[0070] The lenses in the first zoom lens group G2 to the fixed lens group G7 are all spherical lenses.

[0071] The cost of zoom projection lenses has been reduced by using a large number of spherical lenses.

[0072] The zoom projection lens satisfies the following condition:

[0073] -1.2 < FG1 / fw < -1;

[0074] Wherein, FG1 is the focal length of the focusing lens group G1.

[0075] By limiting the focal length of the focusing lens group G1, stable correction of the rear lens group by the focusing lens group G1 is achieved, reducing aberrations and coma of the zoom projection lens.

[0076] The zoom projection lens satisfies the following condition:

[0077] 1.5 < XG4 / fw < 2;

[0078] Wherein, XG4 is the moving distance of the third zoom lens group G4.

[0079] By limiting the moving distance of the third zoom lens group G4, zoom projection can be focused within a certain range, while avoiding the possibility of the zoom lens group being too large, thus achieving miniaturization of the zoom projection lens.

[0080] The zoom projection lens satisfies the following condition:

[0081] 3 < FG3 / fw < 5;

[0082] Wherein, FG3 is the focal length of the second zoom lens group G3.

[0083] By limiting the focal length of the second zoom group, the receiving efficiency of the third zoom lens group G4 in receiving light from the second zoom lens group G3 is increased, thereby increasing the resolution of the zoom projection lens.

[0084] The zoom projection lens satisfies the following condition:

[0085] |Rb12| > 200mm;

[0086] Wherein, Rb12 is the radius of curvature of the curved surface of the first fixed lens b1 near the image plane.

[0087] By limiting the radius of curvature of the first fixed lens b1, the dissipation of light rays from the first fixed lens b1 to the beam splitter P is reduced, thereby increasing the brightness of the zoom projection lens.

[0088] Example 2

[0089] like Figures 1 to 5 As shown, a zoom projection lens is composed of, from the object plane side to the image plane side, a focusing lens group G1 with negative optical power, a first zoom lens group G2 with positive optical power, a second zoom lens group G3 with positive optical power, a third zoom lens group G4 with positive optical power, a fourth zoom lens group G5 with negative optical power, a fifth zoom lens group G6 with positive optical power, a fixed lens group G7 with positive optical power, and a beam splitter P.

[0090] The focusing lens group G1 consists of a first focusing lens a1 with negative optical power, a second focusing lens a2 with negative optical power, and a third focusing lens a3 with negative optical power, sequentially from the object plane side to the image plane side.

[0091] The first zoom lens group G2 is a positive optical power first zoom lens c1;

[0092] The second zoom lens group G3 consists of a second zoom lens c2 with positive optical power and a third zoom lens c3 with negative optical power, arranged sequentially from the object plane side to the image plane side. The second zoom lens c2 and the third zoom lens c3 are cemented together.

[0093] The third zoom lens group G4 is a fourth zoom lens c4 with positive optical power;

[0094] The fourth zoom lens group G5 is a fifth zoom lens c5 with negative optical power;

[0095] The fifth zoom lens group G6 consists of, from the object plane side to the image plane side, a sixth zoom lens c6 with positive optical power, a seventh zoom lens c7 with negative optical power, an eighth zoom lens c8 with positive optical power, a ninth zoom lens c9 with negative optical power, a tenth zoom lens c10 with positive optical power, and an eleventh zoom lens c11 with positive optical power. The seventh zoom lens c7 and the eighth zoom lens c8 are cemented together, and the ninth zoom lens c9 and the tenth zoom lens c10 are cemented together.

[0096] The fixed lens group G7 is a first fixed lens b1 with positive optical power;

[0097] The basic lens data of the zoom projection lens in this embodiment is shown in Table 1, the variable parameters in Table 1 are shown in Table 2, and the aspherical coefficients are shown in Table 3.

[0098] The surface number column shows the surface number when the object-side surface is set as surface 1 and the numbering is increased sequentially towards the image side; the surface type column shows the surface type of a lens; the radius of curvature column shows the radius of curvature of a lens, where a positive radius of curvature indicates that the surface is curved towards the object side and a negative radius of curvature indicates that the surface is curved towards the image side; the center thickness column shows the surface spacing on the optical axis between each surface and the surface adjacent to it on the image side; the refractive index column shows the refractive index of a lens; and the Abbe number column shows the Abbe number of a lens.

[0099] In Table 2, the WIDE column indicates the specific values ​​of each variable parameter when the zoom projection lens is in the wide-angle end state, and the TELE column indicates the specific values ​​of each variable parameter when the zoom projection lens is in the telephoto end state.

[0100] In Table 3, K is the conic coefficient, and e is the scientific notation, for example, e-05 represents 10. -5 .

[0101] Table 1

[0102]

[0103]

[0104] Table 2

[0105] WIDE TELE D1 11.39 5.0 D2 0.5 4.3 D3 23.64 0.5 D4 6.54 28.2 D5 5.32 0.5 D6 0.5 9.4

[0106] Table 3

[0107]

[0108] In this embodiment, fw = 15.3 mm, ft = 24.6 mm, ft / fw = 1.61, fno = 1.58~1.99, and TTL = 163.1 mm;

[0109] fw is the focal length of the zoom projection lens in wide-angle mode, ft is the focal length of the zoom projection lens in telephoto mode, fno is the aperture number of the zoom projection lens, and TTL is the total optical length of the zoom projection lens.

[0110] FG1=-16.44mm, FG1 / fw=-1.07;

[0111] Wherein, FG1 is the focal length of the focusing lens group G1.

[0112] XG4=25.8mm, XG4 / fw=1.69;

[0113] Wherein, XG4 is the moving distance of the third zoom lens group G4.

[0114] FG3=67.07mm, FG3 / fw=4.38;

[0115] Wherein, FG3 is the focal length of the second zoom lens group G3.

[0116] Rb12 = 691.43 mm;

[0117] Wherein, Rb12 is the radius of curvature of the curved surface of the first fixed lens b1 near the image plane.

[0118] Example 3

[0119] like Figures 6 to 10 As shown, a zoom projection lens is composed of, from the object plane side to the image plane side, a focusing lens group G1 with negative optical power, a first zoom lens group G2 with positive optical power, a second zoom lens group G3 with positive optical power, a third zoom lens group G4 with positive optical power, a fourth zoom lens group G5 with negative optical power, a fifth zoom lens group G6 with positive optical power, a fixed lens group G7 with positive optical power, and a beam splitter P.

[0120] The focusing lens group G1 consists of a first focusing lens a1 with negative optical power, a second focusing lens a2 with negative optical power, and a third focusing lens a3 with negative optical power, sequentially from the object plane side to the image plane side.

[0121] The first zoom lens group G2 is a positive optical power first zoom lens c1;

[0122] The second zoom lens group G3 consists of a second zoom lens c2 with positive optical power and a third zoom lens c3 with negative optical power, arranged sequentially from the object plane side to the image plane side. The second zoom lens c2 and the third zoom lens c3 are cemented together.

[0123] The third zoom lens group G4 is a fourth zoom lens c4 with positive optical power;

[0124] The fourth zoom lens group G5 is a fifth zoom lens c5 with negative optical power;

[0125] The fifth zoom lens group G6 consists of, from the object plane side to the image plane side, a sixth zoom lens c6 with positive optical power, a seventh zoom lens c7 with negative optical power, an eighth zoom lens c8 with positive optical power, a ninth zoom lens c9 with negative optical power, a tenth zoom lens c10 with positive optical power, and an eleventh zoom lens c11 with positive optical power. The seventh zoom lens c7 and the eighth zoom lens c8 are cemented together, and the ninth zoom lens c9 and the tenth zoom lens c10 are cemented together.

[0126] The fixed lens group G7 is a first fixed lens b1 with positive optical power;

[0127] The basic lens data of the zoom projection lens in this embodiment is shown in Table 4, the variable parameters in Table 4 are shown in Table 5, and the aspherical coefficients are shown in Table 6.

[0128] The surface number column shows the surface number when the object-side surface is set as surface 1 and the numbering is increased sequentially towards the image side; the surface type column shows the surface type of a lens; the radius of curvature column shows the radius of curvature of a lens, where a positive radius of curvature indicates that the surface is curved towards the object side and a negative radius of curvature indicates that the surface is curved towards the image side; the center thickness column shows the surface spacing on the optical axis between each surface and the surface adjacent to it on the image side; the refractive index column shows the refractive index of a lens; and the Abbe number column shows the Abbe number of a lens.

[0129] In Table 5, the WIDE column indicates the specific values ​​of each variable parameter when the zoom projection lens is in the wide-angle end state, and the TELE column indicates the specific values ​​of each variable parameter when the zoom projection lens is in the telephoto end state.

[0130] In Table 6, K is the conic coefficient, and e is the scientific notation, for example, e-05 represents 10. -5 .

[0131] Table 4

[0132] Face number Surface type radius of curvature / mm Center thickness / mm Refractive index Abbe number OBJ S1 aspherical -44.57 4.60 1.51 56.58 S2 aspherical -68.90 1.00 S3 spherical 55.49 1.80 1.49 70.45 S4 spherical 20.26 13.25 S5 spherical -33.47 1.60 1.66 50.86 S6 spherical 59.60 D1 S7 spherical 632.63 3.28 1.95 17.98 S8 spherical -112.52 D2 S9 spherical 69.81 9.46 1.80 46.50 S10 spherical -37.65 1.60 1.85 23.78 S11 spherical -82.39 D3 S12 spherical 58.68 3.01 1.62 63.40 S13 spherical -201.08 D4 STO spherical -28.04 1.00 1.80 46.50 S15 spherical 84.27 D5 S16 spherical 50.61 4.39 1.83 37.34 S17 spherical -42.36 3.01 S18 spherical -149.64 1.00 1.81 25.46 S19 spherical 28.90 7.03 1.44 95.10 S20 spherical -24.72 0.99 S21 spherical -21.69 1.00 1.81 25.46 S22 spherical 43.03 6.68 1.50 81.61 S23 spherical -32.52 0.50 S24 spherical 122.54 4.41 1.95 17.98 S25 spherical -67.05 D6 S26 spherical 60.72 4.33 1.76 52.33 S27 spherical -282.67 1.67 S28 spherical INF 28.97 1.52 63.88 S29 spherical INF 8.76 S30 spherical INF 1.00 IMG

[0133] Table 5

[0134]

[0135]

[0136] Table 6

[0137]

[0138] In this embodiment, fw = 15.3 mm, ft = 24.6 mm, ft / fw = 1.61, fno = 1.58~2.02, and TTL = 166 mm;

[0139] fw is the focal length of the zoom projection lens in wide-angle mode, ft is the focal length of the zoom projection lens in telephoto mode, fno is the aperture number of the zoom projection lens, and TTL is the total optical length of the zoom projection lens.

[0140] FG1=-16.7mm, FG1 / fw=-1.09;

[0141] Wherein, FG1 is the focal length of the focusing lens group G1.

[0142] XG4=30.4mm, XG4 / fw=1.99;

[0143] Wherein, XG4 is the moving distance of the third zoom lens group G4.

[0144] FG3=49.95mm, FG3 / fw=3.26;

[0145] Wherein, FG3 is the focal length of the second zoom lens group G3.

[0146] Rb12 = -282.67 mm;

[0147] Wherein, Rb12 is the radius of curvature of the curved surface of the first fixed lens b1 near the image plane.

[0148] Example 4

[0149] An imaging device, such as Figures 1 to 10 As shown, it includes: a zoom projection lens as described in any of the above embodiments, and an imaging element configured to receive an image formed by the zoom projection lens.

[0150] It should be noted that the above embodiments can be freely combined as needed. The above description is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A zoom projection lens, characterized in that, The zoom projection lens consists of, from the object plane side to the image plane side, a focusing lens group with negative optical power, a first zoom lens group with positive optical power, a second zoom lens group with positive optical power, a third zoom lens group with positive optical power, a fourth zoom lens group with negative optical power, a fifth zoom lens group with positive optical power, a fixed lens group with positive optical power, and a beam splitter. The focusing lens group consists of a first focusing lens with negative optical power, a second focusing lens with negative optical power, and a third focusing lens with negative optical power, sequentially from the object plane side to the image plane side. The first zoom lens group is a single zoom lens with positive optical power; The second zoom lens group consists of a second zoom lens with positive optical power and a third zoom lens with negative optical power, arranged sequentially from the object plane side to the image plane side, and the second zoom lens and the third zoom lens are cemented together. The third zoom lens group is a fourth zoom lens with positive optical power; The fourth zoom lens group is a fifth zoom lens with negative optical power; The fifth zoom lens group consists of a sixth zoom lens with positive optical power, a seventh zoom lens with negative optical power, an eighth zoom lens with positive optical power, a ninth zoom lens with negative optical power, a tenth zoom lens with positive optical power, and an eleventh zoom lens with positive optical power, from the object plane side to the image plane side. The seventh and eighth zoom lenses are cemented together, and the ninth and tenth zoom lenses are cemented together. The fixed lens group is a first fixed lens with positive optical power; The zoom projection lens satisfies the following condition: 1.5 < ft / fw < 1.8; 1.5 < fno < 2.2; -1.2 < FG1 / fw < -1; Wherein, fw is the focal length of the zoom projection lens in wide-angle mode, ft is the focal length of the zoom projection lens in telephoto mode, fno is the aperture number of the zoom projection lens, and FG1 is the focal length of the focusing lens group.

2. A zoom projection lens according to claim 1, characterized in that: All lenses in the first zoom lens group to the fixed lens group are spherical lenses.

3. A zoom projection lens according to claim 1, characterized in that: The zoom projection lens satisfies the following condition: 1.5 < XG4 / fw < 2; Wherein, XG4 is the moving distance of the third zoom lens group.

4. A zoom projection lens according to claim 1, characterized in that: The zoom projection lens satisfies the following condition: 3 < FG3 / fw < 5; Wherein, FG3 is the focal length of the second zoom lens group.

5. A zoom projection lens according to claim 1, characterized in that: The zoom projection lens satisfies the following condition: |Rb12| > 200mm; Wherein, Rb12 is the radius of curvature of the curved surface of the first fixed lens near the image plane.

6. An imaging device, characterized in that, include: The zoom projection lens as described in any one of claims 1 to 5; An imaging element is configured to receive an image formed by the zoom projection lens.

Images