Zoom lens and projector

Abstract

The present invention provides a zoom lens and a projector. The zoom lens includes a first lens group, a second lens group, a third lens group, a fourth lens group, and a fifth lens group, which are arranged in sequence from a projection surface to an image source surface. The second lens group, the third lens group, and the fourth lens group move along the optical axis respectively. The ratio of the total optical length of the lens to the zoom ratio and the ratio to the telephoto focal length are within a predetermined lens value range. The total optical length of the lens is less than a lens length threshold. The zoom ratio is within a predetermined range. Light from the light source is processed in sequence by the fifth lens group and the first lens group before being projected onto the projection surface. This solution limits the total optical length of the zoom lens, increasing the longest focal length of the zoom lens relative to the shortest focal length. Since the zoom ratio is proportional to the ratio of the longest focal length to the shortest focal length, this solution increases the zoom ratio of the zoom lens and enables the zoom lens to achieve a variety of focal length changes.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of projection technology, and in particular to a zoom lens and a projector. Background Art

[0002] As projector technology matures, its primary focus is on producing clear images. Projection technology relies on multiple lens groups for zooming or fixing, and optical zoom lenses have become the dominant solution in the projection market. Therefore, the focal length of each lens group and the lens combination architecture within each group affect projection image quality. Properly controlling the optical power distribution of each lens group and the travel distance of the lens groups are key design considerations. Conventional projection technology utilizes coordinated lens groups. For example, the inclusion of plastic aspheric lenses within a lens group can simplify the structure and reduce weight. However, conventional projection technology exhibits relatively low zoom, making it difficult to achieve multiple focal length variations. Summary of the Invention

[0003] The embodiments of the present invention provide a zoom lens and a projector, which can improve the zoom ratio of the lens.

[0004] The technical solution of the present invention is achieved as follows:

[0005] An embodiment of the present invention provides a zoom lens, comprising:

[0006] A first lens group, a second lens group, a third lens group, a fourth lens group, and a fifth lens group are sequentially arranged from the projection surface to the image source surface, wherein the second lens group, the third lens group, and the fourth lens group are respectively moved along the optical axis;

[0007] The ratio of the total optical length of the lenses of the first to fifth lens groups to the zoom ratio, and then to the telephoto focal length, is within a predetermined lens value range; the total optical length of the lenses is less than a lens length threshold; wherein the zoom ratio is within a predetermined range;

[0008] Light from the light source is processed in sequence by the fifth lens group, the fourth lens group, the third lens group, the second lens group and the first lens group to be projected onto a projection surface.

[0009] In the above solution, the ratio of the focal length of the first lens group corresponding to the first lens group to the short focal length of the zoom lens is within a range of -2.7 to -1.6;

[0010] a ratio of a second lens group focal length corresponding to the second lens group to the short focal length of the zoom lens within a range of 3.1 to 5.7;

[0011] A ratio of a third lens group focal length corresponding to the third lens group to the short focal length of the zoom lens is within a range of 6.4 to 8.2;

[0012] The ratio of the focal length of the fourth lens group corresponding to the fourth lens group to the short focal length of the zoom lens is within a range of 9 to 16;

[0013] The ratio of the focal length of the fifth lens group corresponding to the fifth lens group to the short-focus focal length of the zoom lens is 3.4 to 4.6; the short-focus focal length is the focal length of the zoom lens in the short-focus state.

[0014] In the above solution, the lens value range includes: 3.8 to 6; the lens length threshold is 115 mm.

[0015] In the above solution, the ratio of the effective focal length of the zoom lens to the aperture diameter is within a range of 1.5 to 1.8; wherein the effective focal length is the distance from the zoom lens to the focus.

[0016] In the above solution, the ratio of the distance from the last lens element of the fifth lens group to the image source plane to the effective focal length of the zoom lens is greater than 1.6;

[0017] The ratio of the moving distance of the second lens group to the length from the first lens of the first lens group to the last lens of the fifth lens group is within a range of 0.01 to 0.08;

[0018] The ratio of the moving distance of the fourth lens group to the moving distance of the second lens group is within 0.5 to 1.

[0019] In the above solution, the first lens group includes: a first lens, a second lens, a third lens and a fourth lens;

[0020] A ratio of an aperture of the first lens to an aperture of the second lens group is less than an aperture threshold;

[0021] The aperture of the first lens is greater than 50 mm; the apertures of the second lens, the third lens, and the fourth lens are less than 32 mm;

[0022] The distance between any two adjacent lenses among the first lens, the second lens, the third lens and the fourth lens is a constant.

[0023] In the above solution, the aperture threshold includes: 1.4375; the aperture of the first lens is less than 58 mm.

[0024] In the above solution, the second lens group includes: a fifth lens; the aperture of the fifth lens is less than 32 mm.

[0025] In the above solution, the third lens group includes: a sixth lens; the aperture of the sixth lens is less than 32 mm.

[0026] In the above solution, the third lens group includes: a sixth lens and a seventh lens; the apertures of the sixth lens and the seventh lens are both less than 32 mm;

[0027] The sixth lens and the seventh lens form a first doublet lens group.

[0028] In the above solution, the fourth lens group includes: an eighth lens, a ninth lens, a tenth lens, an eleventh lens and a twelfth lens;

[0029] The eighth lens is a negative optical power aspheric lens;

[0030] The ninth lens, the tenth lens and the eleventh lens form a first cemented lens group;

[0031] The Abbe number of the twelfth lens is greater than 80.

[0032] In the above solution, the fourth lens group includes: an eighth lens, a ninth lens, a tenth lens, an eleventh lens and a twelfth lens;

[0033] The eighth lens is a negative optical power aspheric lens;

[0034] The ninth lens and the tenth lens form a second doublet lens group;

[0035] The eleventh lens and the twelfth lens form a third doublet lens group.

[0036] In the above solution, the fourth lens group includes: an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens and a thirteenth lens;

[0037] The eighth lens is a negative optical power aspheric lens;

[0038] The ninth lens, the tenth lens and the eleventh lens form a second triplet lens group;

[0039] An Abbe number of the twelfth lens or the thirteenth lens is greater than 80.

[0040] In the above solution, the distance between any two adjacent lenses in the fourth lens group is a constant value;

[0041] An aperture is provided between the third lens group and the fourth lens group. The aperture moves along the optical axis with the fourth lens group, and its relative position to the fourth lens group remains unchanged.

[0042] In the above solution, the fifth lens group includes: a fourteenth lens; the aperture of the fourteenth lens is less than 32 mm.

[0043] In the above solution, the refractive powers of the first lens group, the second lens group, the third lens group, the fourth lens group and the fifth lens group are negative, positive, positive, positive and positive, respectively.

[0044] An embodiment of the present invention further provides a projector including: the zoom lens as described above.

[0045] In an embodiment of the present invention, a zoom lens includes a first lens group, a second lens group, a third lens group, a fourth lens group, and a fifth lens group, which are sequentially arranged from a projection surface to an image source surface. The second lens group, the third lens group, and the fourth lens group are movable along the optical axis. The ratio of the total optical length of the first lens group to the fifth lens group to the zoom ratio and the ratio to the telephoto focal length are within a predetermined lens value range. The total optical length of the lens is less than a lens length threshold. The zoom ratio is within a predetermined range. Light from the light source is sequentially processed by the fifth lens group, the fourth lens group, the third lens group, the second lens group, and the first lens group to be projected onto the projection surface. Since this solution limits the total optical length of the zoom lens, the longest focal length of the zoom lens is increased relative to the shortest focal length. Since the zoom ratio is proportional to the ratio of the longest focal length to the shortest focal length, this solution increases the zoom ratio of the zoom lens and enables the zoom lens to achieve a variety of focal length changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A schematic diagram of an optional structure of a zoom lens provided in an embodiment of the present invention;

[0047] Figure 2 A schematic diagram of an optional structure of a zoom lens provided in an embodiment of the present invention;

[0048] Figure 3 A schematic diagram of an optional structure of a zoom lens provided in an embodiment of the present invention;

[0049] Figure 4 A schematic diagram of an optional structure of a zoom lens provided in an embodiment of the present invention;

[0050] Figure 5 A schematic diagram of an optional structure of a zoom lens provided in an embodiment of the present invention;

[0051] Figure 6 A schematic structural diagram of a projector provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention are further elaborated in detail below with reference to the accompanying drawings and embodiments. The described embodiments should not be regarded as limiting the present invention. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0053] In the following description, reference is made to “some embodiments”, which describes a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0054] If similar descriptions of "first / second" appear in the invention document, the following explanation is added. In the following description, the terms "first\second\third" involved are only used to distinguish similar objects and do not represent a specific order for the objects. It can be understood that "first\second\third" can be interchanged with the specific order or sequence where permitted, so that the embodiments of the invention described herein can be implemented in an order other than that illustrated or described herein.

[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The terms used herein are for the purpose of describing embodiments of the present invention only and are not intended to limit the present invention.

[0056] See also Figure 1 , is a schematic diagram of an optional structure of a zoom lens provided in an embodiment of the present invention.

[0057] An embodiment of the present invention provides a zoom lens, including a first lens group G1, a second lens group G2, a third lens group G3, a fourth lens group G4 and a fifth lens group G5.

[0058] The first lens group G1, the second lens group G2, the third lens group G1, the fourth lens group G4 and the fifth lens group G5 are sequentially arranged from the projection surface 100 to the image source surface 200. The second lens group G2, the third lens group G3 and the fourth lens group G4 move along the optical axis 101 respectively.

[0059] The ratio of the total optical length of the first lens group G1 to the fifth lens group G5 to the zoom ratio, and then to the telephoto focal length, is within a predetermined lens value range; the total optical length of the lens is less than a lens length threshold. The zoom ratio is within the predetermined range.

[0060] Light from the light source 102 is sequentially processed by the fifth lens group G5 , the fourth lens group G4 , the third lens group G3 , the second lens group G2 , and the first lens group G1 to be projected onto the projection surface 100 .

[0061] In the embodiment of the present invention, the predetermined range is the range after the zoom ratio value range of the zoom lens is expanded in the related art.

[0062] In this embodiment of the present invention, the second lens group G2, the third lens group G3, and the fourth lens group G4 can each move along the optical axis toward the projection plane 100 or the image source plane 200. The second lens group G2, the lens group G3, and the lens group G4 constitute a mobile zoom group. When the zoom group moves toward the projection plane 100, the zoom lens is in a telephoto state, at which point the focal length of the zoom lens is long and the zoom lens is at a low magnification. When the zoom group moves toward the image source plane 200, the zoom lens is in a shortphoto state, at which point the focal length of the zoom lens is short and the zoom lens is at a high magnification.

[0063] In the embodiment of the present invention, the ratio of the focal length of the first lens group G1 to the short focal length of the zoom lens is within a range of -2.7 to -1.6; the short focal length is the focal length of the zoom lens in the short focal state.

[0064] A ratio of the second lens group focal length of the second lens group G2 to the short focal length of the zoom lens is within a range of 3.1 to 5.7.

[0065] The ratio of the focal length of the third lens group of the third lens group G3 to the short focal length of the zoom lens is within a range of 6.4 to 8.2.

[0066] A ratio of the focal length of the fourth lens group of the fourth lens group G4 to the short focal length of the zoom lens is within a range of 9 to 16.

[0067] A ratio of the focal length of the fifth lens group of the fifth lens group G5 to the short focal length of the zoom lens is within a range of 3.4 to 4.6.

[0068] In this embodiment of the present invention, when the zoom ratio is 1.5, the ratio of the focal length of the first lens group of the first lens group G1 to the short-focus focal length of the zoom lens is -1.6. The ratio of the focal length of the second lens group of the second lens group G2 to the short-focus focal length of the zoom lens is 3.1. The ratio of the focal length of the third lens group of the third lens group G3 to the short-focus focal length of the zoom lens is 6.4. The ratio of the focal length of the fourth lens group of the fourth lens group G4 to the short-focus focal length of the zoom lens is 9. The focal length of the fifth lens group of the fifth lens group G5 to the short-focus focal length of the zoom lens is 3.4.

[0069] When the zoom ratio is 1.55, the ratio of the focal length of the first lens group of the first lens group G1 to the short-focus focal length of the zoom lens is -2.1. The ratio of the focal length of the second lens group of the second lens group G2 to the short-focus focal length of the zoom lens is 4.3. The ratio of the focal length of the third lens group of the third lens group G3 to the short-focus focal length of the zoom lens is 7.3. The ratio of the focal length of the fourth lens group of the fourth lens group G4 to the short-focus focal length of the zoom lens is 12.5. The focal length of the fifth lens group of the fifth lens group G5 to the short-focus focal length of the zoom lens is 4.

[0070] When the zoom ratio is 1.6, the ratio of the focal length of the first lens group of the first lens group G1 to the short-focus focal length of the zoom lens is -2.7. The ratio of the focal length of the second lens group of the second lens group G2 to the short-focus focal length of the zoom lens is 5.7. The ratio of the focal length of the third lens group of the third lens group G3 to the short-focus focal length of the zoom lens is 8.2. The ratio of the focal length of the fourth lens group of the fourth lens group G4 to the short-focus focal length of the zoom lens is 16. The focal length of the fifth lens group of the fifth lens group G5 to the short-focus focal length of the zoom lens is 4.6.

[0071] In this embodiment of the present invention, the predetermined lens value range includes: 3.8 to 6. The lens length threshold is 115 mm. In other words, the ratio of the zoom lens's total optical length to the zoom ratio, and then to the telephoto focal length, is within a range of 3.8 to 6; the total optical length of the lens is less than 115 mm.

[0072] In this embodiment of the present invention, when the zoom ratio is 1.5, the ratio of the total optical length of the zoom lens to the zoom ratio, and then to the telephoto focal length, is 6. When the zoom ratio is 1.55, the ratio of the total optical length of the zoom lens to the zoom ratio, and then to the telephoto focal length, is 4.9. When the zoom ratio is 1.6, the ratio of the total optical length of the zoom lens to the zoom ratio, and then to the telephoto focal length, is 3.8.

[0073] In the embodiment of the present invention, the ratio of the effective focal length of the zoom lens to the aperture diameter is within a range of 1.5 to 1.8.

[0074] The effective focal length is the distance from the zoom lens to the focal point.

[0075] In this embodiment of the present invention, the distance from the last lens element of the fifth lens group G5 to the image source plane 200 is greater than 1.6 times the effective focal length of the zoom lens. The ratio of the travel distance of the second lens group G2 to the length from the first lens element of the first lens group G1 to the last lens element of the fifth lens group G5 is within a range of 0.01 to 0.08. The ratio of the travel distance of the fourth lens group G4 to the travel distance of the second lens group G2 is within a range of 0.5 to 1.

[0076] In the embodiment of the present invention, the second lens group G2, the third lens group G3 and the fourth lens group G4 can be moved left and right along the optical axis respectively. The distances that the second lens group G2, the third lens group G3 and the fourth lens group G4 move can be the same or different. The directions in which the second lens group G2, the third lens group G3 and the fourth lens group G4 move can be the same or different. In the embodiment of the present invention, the second lens group G2 or the third lens group G3 or the fourth lens group G4 can remain stationary, and the remaining two lens groups in the second lens group G2, the third lens group G3 and the fourth lens group G4 can be moved left and right along the optical axis respectively. In the embodiment of the present invention, the second lens group G2 or the third lens group G3 or the fourth lens group G4 can be moved left and right along the optical axis respectively, and the remaining two lens groups in the second lens group G2, the third lens group G3 and the fourth lens group G4 can be stationary.

[0077] In the embodiment of the present invention, combined with Figure 1 The light emitted by the light source 102 is magnified by the fifth lens group G5 and then transmitted to the fourth lens group G4. The fourth lens group G4 corrects the spherical aberration and chromatic aberration of the incident light and then transmits it to the third lens group G3. The third lens group G3 adjusts the aperture of the incident light and then transmits it to the second lens group G2. The second lens group G2 adjusts the propagation angle of the incident light and then transmits it to the first lens group G1. The first lens group G1 diverges the incident light and then projects it onto the projection surface 100. The effective focal length of each lens group is within the numerical range corresponding to each lens group compared to the short focal length of the zoom lens. The ratio of the total optical length of the zoom lens to the zoom ratio and then to the long focal length are within a predetermined lens value range; the total optical length of the lens is less than a lens length threshold; wherein, the zoom ratio is within a predetermined range; because this solution limits the ratio between the effective focal length of each lens group and the short focal length, and also limits the total optical length of the zoom lens, the longest focal length of the zoom lens is increased compared to the shortest focal length; and because the zoom ratio is proportional to the ratio of the longest focal length to the shortest focal length, this solution increases the zoom ratio of the zoom lens and enables the zoom lens to achieve a variety of focal length changes.

[0078] An embodiment of the present invention provides a zoom lens, which is exemplarily combined with Figure 2. Among them, the first lens group G1 includes an aspheric mirror L1 with negative focal power, a second lens L2 with negative focal power, a third lens L3 with negative focal power and a fourth lens L4 with positive focal power. The first lens G1 assumes the function of correcting the distortion of the incident light, which is beneficial to improving the field of view of the system. It can well correct off-axis aberrations such as distortion, coma, field curvature and astigmatism, ensuring that the incident angle of the light on the lens surface is relatively flat, and no large high-order aberrations are generated while having a large field of view. The second lens group G2, the third lens group G3 and the fourth lens group G4 can achieve optical zoom by moving different distances. This makes the zoom ratio of the zoom lens between 1.5 and 1.6. Among them, the third lens group G3 with positive focal power plays the role of correcting chromatic aberration and controlling the beam aperture. An aperture is arranged between the third lens group G3 and the fourth lens group G4. During the zooming process, the aperture moves with the fourth lens group G4, and the relative position of the aperture and the fourth lens group G4 remains unchanged. The fourth lens group G4 with positive optical power includes a negative optical power aspheric lens and a triplet lens group or a doublet lens group. The fourth lens group G4 can effectively correct the spherical aberration and chromatic aberration of the incident light. At the same time, since the aperture is used to limit the light emitted by the fourth lens group G4, when the relative position of the aperture and the fourth lens group G4 remains unchanged, the light emitted by the fourth lens group G4 to the third lens group G3 can be made more stable.

[0079] In the embodiment of the present invention, the focal lengths of the first lens group G1, the second lens group G2, the third lens group G3, the fourth lens group G4 and the fifth lens group G5 satisfy the following conditional formula:

[0080] -2.7 <F1 / Fs<-1.6

[0081] 3.1 <F2 / Fs<5.7

[0082] 6.4 <F3 / Fs<8.2

[0083] 9.0 <F4 / Fs<16

[0084] 3.4 <F5 / Fs<4.6

[0085] Wherein, F1, F2, F3, F4, and F5 are the focal lengths of the first lens group G1, the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5, respectively. Fs is the short focal length of the zoom lens.

[0086] In the embodiment of the present invention, the total optical length of the zoom lens, the zoom ratio, and the telephoto focal length also satisfy the following conditional expressions:

[0087] 3.8 <OLL / ZR / FL<6.0

[0088] OLL<115mm

[0089] Among them, OLL (Optical lens length) is the total optical length of the lens (the distance from the first lens to the last lens of the lens), ZR (Zoom ratio) is the zoom ratio, and FL (Optical lens length) is the telephoto focal length of the zoom lens.

[0090] In the embodiment of the present invention, the back focal length of the zoom lens and the change in the moving distance of each lens group also satisfy the following expression:

[0091] 1.60 <BF / EFL

[0092] 0.01 <X2 / TTL<0.08

[0093] 0.5 <X4 / X2<1

[0094] Where BF (Back Focal Length) is the back focal length of the zoom lens (the distance from the last lens to the image plane), EFL (Effective Focal Length) is the effective focal length of the zoom lens, X2 is the distance moved by the second lens group G2, X4 is the distance moved by the fourth lens group G4, and TTL (Total Track Length) is the total length of the lens (the distance from the first lens to the digital micromirror device (DMD)).

[0095] In the embodiment of the present invention, the aperture of the zoom lens satisfies the following conditions:

[0096] 1.4375>ΦL1 / ΦL2

[0097] Wherein, ΦL1 is the aperture of the first lens L1, ΦL2 is the aperture of the second lens L2, and ΦL1<58 mm.

[0098] In this embodiment of the present invention, the fourth lens group G4 can correct chromatic aberration, and the twelfth lens L12 is a high Abbe number lens, satisfying an Abbe number greater than 80. In other words, the twelfth lens has a small dispersion, making the output light of the fourth lens group G4 more concentrated.

[0099] In the embodiment of the present invention, as a preferred design technical solution, the zoom lens further meets the following conditions:

[0100] 1.68 < BF / EFL; and BF > 20 mm. The aperture of the first lens L1 on the side closer to the projection surface 100 of this zoom lens is greater than 50 mm, and the apertures of the remaining lenses are less than 32 mm, so that the volume of each lens is limited within a certain range, thereby reducing the volume of the zoom lens. The principle of this invention to improve brightness lies in: Fno = effective focal length of the lens / aperture diameter. The larger the aperture diameter, the larger the light passing port, and the more light rays can be received. Therefore, the Fno designed in this invention is between 1.5 and 1.8. And 10.5 mm < EFL < 16.8 mm. It can project a 70 - 100 - inch image at a distance of 221.4 cm from the projection surface, that is, project a larger image.

[0101] The embodiment of this invention provides a zoom lens with precise structure, achieving a low - cost and compact imaging lens. This application is based on the optical imaging principle. Using optical design software, the curvature radius, material, thickness, air gap of each lens of the projection lens, and the design of two aspherical lenses are repeatedly optimized optically, achieving very small aberration, high resolution, compact structure, ingenious design, high mass - production manufacturability, light weight, and facilitating mass production.

[0102] In the embodiment of this invention, combined with Figure 2 , the number of lenses of the first lens group G1 to the fifth lens group G5 of this zoom lens is controlled between 12 and 14. Among them, the lens T after the fifth lens group G5 is a coated lens, the lens P is a prism, the lens G is a protective lens, and after the lens G, there is also a DMD (that is, the image source surface). DMD is an array composed of multiple high - speed digital light - reflecting switches. DMD is composed of many small aluminum - made reflecting mirrors, and the number of lenses is determined by the display resolution. One small mirror corresponds to one pixel. Compared with the low transmittance and small contrast of liquid crystal, DMD has a high reflectance and large contrast. The object is imaged on the DMD device, and through the pixel - level controllable characteristics of the DMD device and its high - speed flipping frequency, each image point is then scanned onto the detector in sequence to achieve high - speed passive point - scanning imaging of the object under visible light conditions during the day. Adding an appropriate light source can also achieve active - scanning imaging.

[0103] In the embodiment of this invention, the first lens group includes: the first lens, the second lens, the third lens, and the fourth lens.

[0104] The ratio of the aperture of the first lens to the aperture of the second lens group is less than the aperture threshold.

[0105] The aperture of the first lens is greater than 50 mm; the apertures of the second lens, the third lens, and the fourth lens are less than 32 mm.

[0106] The distance between two adjacent lenses among the first lens, the second lens, the third lens, and the fourth lens is a fixed value.

[0107] In the embodiment of the present invention, the apertures of the second lens, the third lens, and the fourth lens of the zoom lens are smaller than 32 mm, so that the volume of the first lens group is controlled within a certain range, thereby further reducing the volume of the zoom lens.

[0108] For example, combined Figure 2 , wherein the first lens group G1 includes: a first lens L1, a second lens L2, a third lens L3 and a fourth lens L4. The quotient of the aperture of the first lens L1 divided by the aperture of the second lens group L2 is less than 1.4375. The aperture of the first lens L1 is greater than 50 mm; the apertures of the second lens L2, the third lens L3 and the fourth lens L4 are all less than 32 mm. The distance between any two adjacent lenses in the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 is a constant. Due to Figure 3 、 Figure 4 and Figure 5 The structure of the first lens group G1 in Figure 1 The structures are the same as in , so I will not go into details here.

[0109] The distances between the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 can all be the same, 1 mm. The distances between the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 can also be different. For example, the distance between the first lens L1 and the second lens L2 is 1 mm, the distance between the second lens L2 and the third lens L3 is 2 mm, and the distance between the third lens L3 and the fourth lens L4 is 3 mm. In this embodiment of the present invention, there is no restriction on the distances between adjacent lenses of the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4.

[0110] The aperture threshold includes: 1.4375. The aperture of the first lens L1 is less than 58 mm.

[0111] In the embodiment of the present invention, combined with Figure 2 The second lens group G2 includes: a fifth lens L5; the aperture of the fifth lens L5 is less than 32 mm.

[0112] In the embodiment of the present invention, the aperture of the fifth lens L5 of the second lens group G2 of the zoom lens is limited to less than 32 mm, so that the volume of the zoom lens can also be controlled within a certain range.

[0113] In the embodiment of the present invention, the third lens group includes: a sixth lens; the aperture of the sixth lens is less than 32 mm.

[0114] For example, combined Figure 3 The third lens group G3 includes a sixth lens L6. The aperture of the sixth lens L6 is less than 32 mm. Figure 4and Figure 3 The structure of the third lens group G3 is the same as that of the first lens group G3, which will not be described in detail here.

[0115] In an embodiment of the present invention, the third lens group includes: a sixth lens and a seventh lens; the apertures of the sixth lens and the seventh lens are both smaller than 32 mm.

[0116] The sixth lens and the seventh lens form a first doublet lens group.

[0117] For example, combined Figure 2 The third lens group G4 includes a sixth lens L6 and a seventh lens L7. The apertures of the sixth lens L6 and the seventh lens L7 are both less than 32 mm. The sixth lens L6 and the seventh lens group L7 form a first cemented doublet lens group. Figure 5 and Figure 2 The structure of the third lens group G3 is the same as that of the first lens group G3, which will not be described in detail here.

[0118] A doublet is a lens formed by gluing two lenses together. This combination of two lenses is an effective way to achieve a short focal length, high magnification, and good image quality.

[0119] In an embodiment of the present invention, the fourth lens group includes an eighth lens, a ninth lens, a tenth lens, an eleventh lens, and a twelfth lens.

[0120] The eighth lens is an aspherical lens with negative optical power.

[0121] The ninth lens, the tenth lens and the eleventh lens constitute a first cemented lens group.

[0122] The Abbe number of the twelfth lens is greater than 80.

[0123] For example, combined Figure 2 The fourth lens group G4 includes: an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, and a twelfth lens L12. Eighth lens L8 is an aspherical lens with negative optical power. Ninth lens L9, tenth lens L10, and eleventh lens group L11 form a first cemented triplet. The Abbe number of twelfth lens L12 is greater than 80.

[0124] A triplet is a lens formed by cementing three lenses together. This combination of two lenses is a lens combination that can correct spherical aberration and chromatic aberration.

[0125] In an embodiment of the present invention, the fourth lens group includes an eighth lens, a ninth lens, a tenth lens, an eleventh lens, and a twelfth lens.

[0126] The eighth lens is an aspherical lens with negative optical power.

[0127] The ninth lens and the tenth lens form a second doublet lens group.

[0128] The eleventh lens and the twelfth lens constitute a third doublet lens group.

[0129] For example, combined Figure 4 The fourth lens group G4 includes: the eighth lens L8, the ninth lens L9, the tenth lens L10, the eleventh lens L11, and the twelfth lens L12. The eighth lens L8 is an aspherical lens with negative optical power. The ninth lens L9 and the tenth lens L10 form a second doublet lens group. The eleventh lens L11 and the twelfth lens group L12 form a third doublet lens group.

[0130] The Abbe number of one of the eighth lens L8, the ninth lens L9, the tenth lens L10, the eleventh lens L11 and the twelfth lens L12 is greater than 80.

[0131] In the embodiment of the present invention, the fourth lens group includes an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, and a thirteenth lens.

[0132] The eighth lens is an aspherical lens with negative optical power.

[0133] The ninth lens, the tenth lens and the eleventh lens constitute a second cemented lens group.

[0134] The Abbe number of the twelfth lens or the thirteenth lens is greater than 80.

[0135] For example, combined Figure 3 The fourth lens group G4 includes: the eighth lens L8, the ninth lens L9, the tenth lens L10, the eleventh lens L11, the twelfth lens L12, and the thirteenth lens L13. The eighth lens L8 is an aspherical lens with negative optical power. The ninth lens L9, the tenth lens L10, and the eleventh lens L11 form a second cemented triplet lens group. The Abbe number of either the twelfth lens L12 or the thirteenth lens L13 is greater than 80. Figure 5 and Figure 3 The structure of the fourth lens group G4 is the same as that of the first lens group G4, which will not be described in detail here.

[0136] In this embodiment of the present invention, the distance between adjacent lenses in the fourth lens group is constant, making the output light from the fourth lens group more stable. An aperture is provided between the third and fourth lens groups. The aperture moves along the optical axis with the fourth lens group, while maintaining a constant relative position to the fourth lens group.

[0137] For example, combined Figure 2The distances between any two adjacent lenses of the fourth lens group, namely, the eighth lens L8, the ninth lens L9, the tenth lens L10, the eleventh lens L11, and the twelfth lens L12, can be the same or different. An aperture stop is provided on the side of the eighth lens L8 closest to the projection plane 100, and the distance between the aperture stop and the eighth lens L8 remains constant.

[0138] In an embodiment of the present invention, the fifth lens group includes a fourteenth lens; the aperture of the fourteenth lens is less than 32 mm.

[0139] In the embodiment of the present invention, the aperture of the fourteenth lens is limited to less than 32 mm in order to control the size of the zoom lens within a certain range.

[0140] For example, combined Figure 2 The fifth lens group G5 includes a fourteenth lens L14; the aperture of the fourteenth lens L14 is less than 32 mm.

[0141] In the embodiment of the present invention, the refractive powers of the first lens group, the second lens group, the third lens group, the fourth lens group and the fifth lens group are negative, positive, positive, positive and positive, respectively.

[0142] For example, combined Figure 2 The negative refractive power of the first lens group G1 helps improve light collection and simplifies optical path design and lens production. The refractive powers of the second lens group G2 through the fifth lens group G5 are positive, positive, positive, and positive, respectively. Furthermore, the positive refractive power of the fifth lens group G5 provides better light-gathering capabilities and enhances projection resolution.

[0143] See also Figure 2 , is a schematic diagram of an optional structure of a zoom lens provided in an embodiment of the present invention. Figure 2 The zoom lens provided in the Figure 2 The zoom lens is described in detail in [1].

[0144] Figure 2 The present invention provides a specific example of a zoom lens. In this example, the first through fifth lens groups comprise 13 lenses. In the figure, the projection surface 100 is on the far left, and the DMD is on the right. Lenses L1 through L13 represent the first through thirteenth lenses, and from left to right, they are L1, L2, L3, L4, L5, L6, L7, L8, L9, L10, L11, L12, and L13, respectively. Lenses L1 through L4 comprise the first lens group G1, which diverges light and corrects distortion and other off-axis aberrations.

[0145]

[0146]

[0147] Table 1

[0148] In an embodiment of the present invention, as shown in Table 1, the parameter distribution of the lens in the telephoto state of the zoom lens is given. The zoom ratio is 1.5 times, and the aperture number Fno is between 1.5 and 1.8. The total optical lens length, zoom ratio and focal length of the zoom lens also meet the following expression: OLL / ZR / FL<6.0. A wide range of optical zoom with an EFL of 10.5mm to 15.8mm can be achieved. The lens groups G2, G3 and G4 can be moved to the telephoto state when moving toward the projection surface, and can be moved to the short focus state when moving toward the DMD direction. And the moving distances X2 and X4 of the lens groups G2 and G4 meet the relationship:

[0149] 0.01 <X2 / TTL<0.08

[0150] 0.5 <X4 / X2<1

[0151] The refractive powers of the first lens group G1 to the fifth lens group G5 are negative, positive, positive, positive, and positive, respectively. Furthermore, the ratios of the focal lengths F1, F2, F3, F4, and F5 of the five lens groups to the short focal length Fs of the zoom lens satisfy the following relationship:

[0152] -2.0 <F1 / Fs<-1.6

[0153] 4.2 <F2 / Fs<5.7

[0154] 6.4 <F3 / Fs<8.2

[0155] 9.0 <F4 / Fs<12

[0156] 3.4 <F5 / Fs<4.6

[0157] The first lens group G1 includes four lenses, such as the first aspheric lens L1, the second lens L2, the third lens L3, and the fourth lens L4. The second lens group G2 includes one lens, such as the fifth lens L5. The third lens group G3 includes two lenses, such as the doublet cemented group of the sixth lens L6 and the seventh lens L7. The fourth lens group G4 includes five lenses, such as the eighth lens L8, the triplet cemented group of the ninth lens L9 and the tenth lens L10, the eleventh lens L11, and the twelfth lens L12. The fifth lens group G5 includes one lens, such as the fourteenth lens L14. In this embodiment, the first lens L1 to the thirteenth lens L13 are arranged in sequence along the optical axis from the projection plane 100 to the DMD. Furthermore, the refractive powers of the first lens L1 to the thirteenth lens L13 are negative, negative, negative, positive, positive, positive, positive, negative, negative, negative, negative, positive, positive, and positive, respectively.

[0158] The distance between any two adjacent lenses in either the first lens group G1 or the fourth lens group G4 is a constant, that is, the distance between any two adjacent lenses in either the first lens group G1 or the fourth lens group G4 does not change with changes in the focal length of the zoom projection lens. Specifically, in the first lens group G1, the distance between the first lens L1 and the second lens L2 is fixed, the distance between the second lens L2 and the third lens L3 is fixed, and the distance between the third lens L3 and the fourth lens L4 is also fixed. Furthermore, in the fourth lens group G4, the distances between the eighth lens L8, the ninth lens L9, the tenth lens L10, the eleventh lens L11, and the twelfth lens L12 are also fixed. In this embodiment of the present invention, the design of the zoom lens having a constant distance between any two adjacent lenses in either the first lens group G1 or the fourth lens group G4 makes the internal structure of the zoom lens more stable and the emitted light more stable.

[0159] Among them, the aperture is set between the third lens group G3 and the fourth lens group G4, and the distance between the aperture position and the eighth lens L8 is fixed. The aperture can effectively reduce the sensitivity of lens L8. The fifth lens group G5 is a rear fixed lens group, which can effectively constrain the beam aperture, ensure a long working distance, and provide sufficient space for the optical elements behind the lens. The back focal length BF and effective focal length EFL meet 1.60 <BF / EFL。

[0160] The sixth lens L6 and the seventh lens L7 are made of a doublet cemented lens. The cemented lens uses a combination of a higher-refractive-index lens and a lower-refractive-index lens, resulting in an achromatic design that minimizes chromatic aberration for the entire optical system. This also effectively reduces the overall length of the third lens group G3.

[0161] The ninth lens element L9, the tenth lens element L10, and the eleventh lens element L11 utilize a cemented triplet. This not only effectively corrects aberrations but also saves space for installing separate lenses, effectively reducing the overall length of the fourth lens group G4. This also greatly simplifies the assembly process, while improving production tolerance and efficiency.

[0162] In the embodiment of the present invention, in the zoom lens, the aspheric polynomial formula is:

[0163]

[0164] Among them, the letter z represents the surface height; c is the curvature; r is the radial coordinate; k is the quadratic coefficient; α is the coefficient.

[0165] S1 S2 S15 S16 A1 -2.34E-05 -6.95E-05 -2.26E-04 -2.94E-04 A2 -3.44E-07 7.36E-07 1.30E-06 2.42E-06 A3 1.41E-08 -1.29E-07 -5.13E-09 -1.80E-08 A4 -7.82E-10 8.96E-09 1.37E-11 1.39E-10 A5 2.32E-11 -3.89E-10 5.32E-11 -9.09E-13 A6 -4.13E-13 5.05E-11 -3.13E-13 4.22E-15 A7 4.11E-15 -1.70E-13 5.11E-15 -1.23E-17 A8 -2.02E-17 1.52E-15 -1.14E-23 -2.69E-20 A9 3.29E-20 -5.80E-18 -1.41E-23 6.93E-27

[0166] Table 2

[0167] The first lens L1 and the eighth lens L8 utilize plastic aspheric lenses, which reduces the lens' weight, volume, and production cost. The relevant aspheric surface parameters are shown in Table 2. A1, A2, A3, A4, A5, A6, A7, A8, and A9 are the fourth to sixteenth-order aspheric coefficients of the aspheric lenses L1 and L8, respectively. The use of aspheric surfaces can correct for various aberrations (such as spherical aberration, coma, astigmatism, field curvature, or distortion). Using aspheric surfaces effectively shortens the overall lens length and facilitates miniaturization of zoom lenses. The total optical length of the lens satisfies OLL < 103mm. The lens aperture can be effectively reduced to: 1.37 > ΦL1 / ΦL2. ΦL1 is the diameter of the first lens L1, and ΦL2 is the diameter of the second lens L2. Furthermore, the clear aperture of the second lens L2 through the thirteenth lens L13 is less than 32mm.

[0168] In this case, the zoom lens has a precise structure, which enables a compact projection lens with low cost, small size and excellent imaging quality.

[0169] See also Figure 3 , is a schematic diagram of an optional structure of a zoom lens provided in an embodiment of the present invention. Figure 3 The zoom lens provided in the Figure 3 The zoom lens is described in detail in [1].

[0170] In an embodiment of the present invention, the zoom lens includes, in order from the projection plane to the DMD, a first lens group G1, a second lens group G2, a third lens group G3, an aperture, a fourth lens group G4, and a fifth lens group G5. The refractive powers of the first through fifth lens groups G1 through G5 are, in order, negative, positive, positive, positive, and positive. The first lens group G1 includes four lenses: a first aspherical lens L1, a second lens L2, a third lens L3, and a fourth lens L4. The second lens group G2 includes one lens, such as the fifth lens L5. The third lens group G3 includes one lens, such as the sixth lens L6. The fourth lens group G4 includes five lenses, such as the eighth lens L8, a cemented ninth lens L9, a tenth lens L10, an eleventh lens L11, a twelfth lens L12, and a thirteenth lens L13. The fifth lens group G5 includes one lens, such as the fourteenth lens L14.

[0171] In this case, as shown in Table 2, the lens distribution of the zoom lens in the telephoto position is given. The zoom ratio is 1.6x, and the aperture number Fno is between 1.5 and 1.8. A wide range of optical zoom, with an EFL of 10.5mm to 16.8mm, is achieved. Lens groups G2, G3, and G4 move toward the projection surface to achieve the telephoto position, and toward the DMD to achieve the short focus position. Furthermore, the movement distances X2 and X4 of lens groups G2 and G4 satisfy the following relationship:

[0172] 0.01 <X2 / TTL<0.08

[0173] 0.5 <X4 / X2<1

[0174] The refractive powers of the first lens group G1 to the fifth lens group G5 are negative, positive, positive, positive, and positive, respectively, and the ratios of the focal lengths F1, F2, F3, F4, and F5 of the five lens groups to the short focal length of the zoom lens satisfy the following relationship:

[0175] -2.0 <F1 / Fs<-1.6

[0176] 4.2 <F2 / Fs<5.7

[0177] 6.4 <F3 / Fs<8.2

[0178] 9.0 <F4 / Fs<12

[0179] 3.7 <F5 / Fs<4.6

[0180] The total length of the optical lens, zoom ratio and telephoto focal length of the projection zoom system also satisfy the following conditional expressions:

[0181] 3.8 <OLL / ZR / FL

[0182] In this case, the third lens group G3 is replaced with a single lens, as shown in Table 3. The fourth lens group G4 consists of six elements, resulting in a reduced optical power. The lens and peripheral element parameters of this zoom lens are shown in Tables 3 and 4. The aspheric coefficient is 20th order.

[0183]

[0184] Table 3

[0185]

[0186]

[0187] Table 4

[0188] The zoom lens's total optical length satisfies OLL < 103mm. The lens aperture can be effectively reduced to: 1.35 > ΦL1 / ΦL2. ΦL1 is the diameter of the first lens element L1, and ΦL2 is the diameter of the second lens element L2. Furthermore, the clear aperture from the second lens element L2 to the fourteenth lens element L14 is less than 34mm.

[0189] See also Figure 4 , is a schematic diagram of an optional structure of a zoom lens provided in an embodiment of the present invention. Figure 4 The zoom lens provided in the Figure 4 The zoom lens is described in detail in [1].

[0190] In an embodiment of the present invention, the projection lens includes, in order from the projection surface to the image reduction end DMD, a first lens group G1, a second lens group G2, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. The refractive powers of the first through fifth lens groups G1 through G5 are, in order, negative, positive, positive, positive, and positive. The first lens group G1 includes four lenses, such as a first aspheric lens L1, a second lens L2, a third lens L3, and a fourth lens L4. The second lens group G2 includes a single lens, such as the fifth lens L5. The third lens group G3 includes a single lens, such as a doublet-cemented sixth lens L6. The fourth lens group G4 includes five lenses, such as an eighth lens L8, a doublet-cemented ninth lens L9 and tenth lens L10, and a doublet-cemented eleventh lens L11 and twelfth lens L12. The fifth lens group G5 includes a single lens, such as the fourteenth lens L14.

[0191] In the embodiment of the present invention, as shown in Table 3, the lens distribution of the zoom lens in the telephoto state is given. The zoom ratio is 1.6 times, and the aperture number Fno is between 1.5 and 1.8. A wide range of optical zoom with an EFL of 10.4mm to 16.5mm can be achieved. The movement distances X2 and X4 of the lens groups G2 and G4 satisfy the relationship:

[0192] X2 / TTL<0.08

[0193] 0.4 <X4 / X2

[0194] The refractive powers of the first lens group G1 to the fifth lens group G5 are negative, positive, positive, positive, and positive, respectively, and the ratios of the focal lengths F1, F2, F3, F4, and F5 of the five lens groups to the short focal length Fs of the zoom lens satisfy the following relationship:

[0195] -2.7 <F1 / Fs<-1.6

[0196] 4.2 <F2 / Fs<5.7

[0197] 6.4 <F3 / Fs<8.2

[0198] 9.0 <F4 / Fs<16

[0199] 3.4 <F5 / Fs<4.6

[0200] The total length of the optical lens, zoom ratio and telephoto focal length of the projection zoom system also satisfy the following conditional expressions:

[0201] 4.3 <OLL / ZR / FL

[0202] In this embodiment of the present invention, the sixth lens L6 of the third lens group G3 is a single lens, effectively reducing costs. The fourth lens group G4, such as the aspherical eighth lens L8, can correct for various aberrations, significantly shortening the lens length. The use of two doublets of the ninth and tenth lenses L9 and L10, and the eleventh and twelfth lenses L11 and L12, effectively corrects chromatic aberration and significantly shortens the lens length.

[0203] In the embodiment of the present invention, the zoom lens uses twelve lens elements and two aspherical surfaces, L1 and L8, which greatly reduces the processing cost. Table 5 below shows the detailed optical data of the zoom lens of a specific example, where surfaces S1 and S2 are the light-entry side surface and light-exit side surface of the first lens element L1, respectively; surfaces S3 and S4 are the light-entry side surface and light-exit side surface of the second lens element L2, respectively; surfaces S5 and S6 are the light-entry side surface and light-exit side surface of the third lens element L3, respectively; surfaces S7 and S8 are the light-entry side surface of the fourth lens element L4, surfaces S9 and S10 are the light-entry side surface and light-exit side surface of the fifth lens element L5, respectively; surfaces S12 and S11 are the light-entry side surface and light-exit side surface of the sixth lens element L Surfaces S16 and S17 are the light incident side surface and light exit side surface of the ninth lens L9, respectively. Surfaces S17 and S18 are the light incident side surface and light exit side surface of the tenth lens L10, respectively. Surface S19 is the light incident side surface of the eleventh lens L11. Surfaces S20 and S21 are the light incident side surface and light exit side surface of the twelfth lens L12, respectively. Surfaces S22 and S23 are the light incident side surface and light exit side surface of the fourteenth lens L14, respectively.

[0204]

[0205] Table 5

[0206] The aspheric coefficients of the first lens L1 and the eighth lens L8 are S1, S2, S14, and S15 surfaces, respectively, as shown in Table 6.

[0207]

[0208]

[0209] Table 6

[0210] The zoom lens's total optical length satisfies OLL < 113mm. The lens aperture can be effectively reduced to: 1.44 > ΦL1 / ΦL2. ΦL1 is the diameter of the first lens element L1, and ΦL2 is the diameter of the second lens element L2. Furthermore, the clear aperture from the second lens element L2 to the twelfth lens element L12 is less than 24mm.

[0211] See also Figure 5 , is a schematic diagram of an optional structure of a zoom lens provided in an embodiment of the present invention. Figure 5 The zoom lens provided in the Figure 5 The zoom lens is described in detail in [1].

[0212] In this embodiment of the present invention, the first lens group G1 of the zoom lens comprises a first lens L1, a second lens L2 (two meniscus lenses), a third lens L3, and a fourth lens L4. The movable lens group G2 comprises a fifth lens L5, and G3 comprises a sixth lens L6 and a seventh lens L7. The rear lens group comprises a movable lens group G4 and a fixed lens group G5. The movable lens group comprises an eighth lens L8, a cemented triplet of lens groups L9, L10, and L11, a twelfth lens L12, and a thirteenth lens L13. G5 comprises a positive fourteenth lens L14.

[0213] The refractive powers of the first lens group G1 to the fifth lens group G5 are negative, positive, positive, positive, and positive, respectively, and the ratios of the focal lengths F1, F2, F3, F4, and F5 of the five lens groups to the short focal length Fs of the zoom lens satisfy the following relationship:

[0214] -2.7 <F1 / Fs<-1.6

[0215] 4.2 <F2 / Fs<5.7

[0216] 6.4 <F3 / Fs<8.2

[0217] 9.0 <F4 / Fs<16

[0218] 3.4 <F5 / Fs<4.6

[0219] The total optical lens length, zoom ratio and telephoto focal length of the zoom lens also satisfy the following conditional expression: OLL / ZR / FL<4.2.

[0220] The third lens group G3 comprises a doublet of the sixth and seventh lenses, L6 and L7. This structure effectively reduces front-group chromatic aberration. The fourth lens group G4 comprises a triplet of the ninth, tenth, and eleventh lenses, L9 and L10, effectively reducing rear-group chromatic aberration. This significantly reduces lens length, improves lens stability, and reduces the sensitivity of the eighth lens, L8, effectively improving production stability and efficiency. The relevant lens data is shown in Table 7. The non-curved surface coefficients are shown in Table 8.

[0221]

[0222] Table 7

[0223]

[0224]

[0225] Table 8

[0226] As shown in Table 8, the aspheric coefficients of the first lens L1 and the eighth lens L8 are A1, A2, A3, A4, A5, A6, A7, A8, and A9 from the fourth to the twentieth order.

[0227] In an embodiment of the present invention, a zoom lens is provided that combines good optical imaging quality, low thermal drift, low distortion, low chromatic aberration, a large zoom ratio, a large aperture, and a short overall length, while also providing lower manufacturing costs and better imaging quality. Furthermore, the optical lens of the embodiment of the present invention includes 12 to 14 lens elements. When the distance on the optical axis between the outermost lens surfaces with refractive power at both ends of the optical lens is less than 113 mm, it can provide a large aperture, high resolution, miniaturization, low thermal drift, and a short overall length, thereby providing an optical lens design with lower manufacturing costs and better imaging quality.

[0228] See also Figure 6 , is a structural diagram of a projector provided in an embodiment of the present invention.

[0229] The embodiment of the present invention further provides a projector 105 including the zoom lens 104 as described above.

[0230] Since the zoom lens 104 limits the total optical length of the zoom lens, the longest focal length of the zoom lens is increased compared to the shortest focal length. Since the zoom ratio is proportional to the ratio of the longest focal length to the shortest focal length, this solution improves the zoom ratio of the projector 105 and enables the projector 105 to achieve a variety of focal length changes.

[0231] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0232] The units described above as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units; they may be located in one place or distributed across multiple network units; some or all of the units may be selected according to actual needs to achieve the purpose of the scheme of this embodiment.

[0233] The above are merely embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A zoom lens, characterized in that: include: The refractive powers of the first lens group, the second lens group, the third lens group, the fourth lens group and the fifth lens group arranged in sequence from the projection plane to the image source plane are negative, positive, positive, positive and positive in sequence, and the second lens group, the third lens group and the fourth lens group are respectively moved along the optical axis; The ratio of the total optical length of the lenses of the first lens group to the fifth lens group to the zoom ratio and the ratio to the telephoto focal length are within a predetermined lens value range; The total optical length of the lens is less than a lens length threshold; wherein the zoom ratio is within a predetermined range; the predetermined lens value range includes: 3.8 to 6; the lens length threshold is 115 mm; the predetermined range is 1.5 to 1.6; the first lens group consists of four lenses; the second lens group consists of one lens; the fifth lens group consists of one lens; the first lens group is used to correct optical distortion; Light from the light source is processed in sequence by the fifth lens group, the fourth lens group, the third lens group, the second lens group and the first lens group to be projected onto a projection surface.

2. The zoom lens according to claim 1, wherein: The ratio of the first lens group focal length corresponding to the first lens group to the short focal length of the zoom lens is within a range of -2.7 to -1.6; a ratio of a second lens group focal length corresponding to the second lens group to the short focal length of the zoom lens within a range of 3.1 to 5.7; A ratio of a third lens group focal length corresponding to the third lens group to the short focal length of the zoom lens is within a range of 6.4 to 8.2; The ratio of the focal length of the fourth lens group corresponding to the fourth lens group to the short focal length of the zoom lens is within a range of 9 to 16; The ratio of the focal length of the fifth lens group corresponding to the fifth lens group to the short-focus focal length of the zoom lens is 3.4 to 4.6; the short-focus focal length is the focal length of the zoom lens in the short-focus state.

3. The zoom lens according to claim 1, wherein: The ratio of the effective focal length of the zoom lens to the aperture diameter is within a range of 1.5 to 1.8; wherein the effective focal length is the distance from the zoom lens to the focus.

4. The zoom lens according to claim 1, wherein: The ratio of the distance between the last lens element of the fifth lens group and the image source plane to the effective focal length of the zoom lens is greater than 1.6; wherein the effective focal length is the distance from the zoom lens to the focus; The ratio of the moving distance of the second lens group to the length from the first lens of the first lens group to the last lens of the fifth lens group is within a range of 0.01 to 0.08; The ratio of the moving distance of the fourth lens group to the moving distance of the second lens group is within 0.5 to 1.

5. The zoom lens according to claim 1, wherein: The first lens group consists of a first lens, a second lens, a third lens and a fourth lens; The ratio of the aperture of the first lens to the aperture of the second lens is greater than an aperture threshold; The aperture of the first lens is greater than 50 mm; the apertures of the second lens, the third lens, and the fourth lens are less than 32 mm; The distance between any two adjacent lenses among the first lens, the second lens, the third lens and the fourth lens is a constant.

6. The zoom lens according to claim 5, wherein: The aperture threshold includes: 1.4375; the aperture of the first lens is less than 58 mm.

7. The zoom lens according to claim 1, wherein: The second lens group consists of a fifth lens; the aperture of the fifth lens is less than 32 mm.

8. The zoom lens according to claim 1, wherein: The third lens group consists of a sixth lens; the aperture of the sixth lens is less than 32 mm.

9. The zoom lens according to claim 1, wherein: The third lens group consists of a sixth lens and a seventh lens; the apertures of the sixth lens and the seventh lens are both less than 32 mm; The sixth lens and the seventh lens form a first doublet lens group.

10. The zoom lens according to claim 1, wherein The fourth lens group consists of an eighth lens, a ninth lens, a tenth lens, an eleventh lens and a twelfth lens; The eighth lens is a negative optical power aspheric lens; The ninth lens, the tenth lens and the eleventh lens form a first cemented lens group; The Abbe number of the twelfth lens is greater than 80.

11. The zoom lens according to claim 1, wherein The fourth lens group consists of an eighth lens, a ninth lens, a tenth lens, an eleventh lens and a twelfth lens; The eighth lens is a negative optical power aspheric lens; The ninth lens and the tenth lens form a second doublet lens group; The eleventh lens and the twelfth lens form a third doublet lens group.

12. The zoom lens according to claim 1, wherein The fourth lens group consists of an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens and a thirteenth lens; The eighth lens is a negative optical power aspheric lens; The ninth lens, the tenth lens and the eleventh lens form a second triplet lens group; An Abbe number of the twelfth lens or the thirteenth lens is greater than 80.

13. The zoom lens according to any one of claims 10 to 12, wherein: The distance between any two adjacent lenses in the fourth lens group is a constant; An aperture is provided between the third lens group and the fourth lens group. The aperture moves along the optical axis with the fourth lens group, and its relative position to the fourth lens group remains unchanged.

14. The zoom lens according to claim 1, wherein: The fifth lens group consists of a fourteenth lens; the aperture of the fourteenth lens is less than 32 mm.

15. A projector, characterized in that: include: The zoom lens according to any one of claims 1 to 14.

Images