A large-magnification continuous zoom projection optical system

Abstract

The application discloses a large-magnification continuous zoom projection optical system and relates to the technical field of light projection. The system can obtain a clear picture at different projection distances by moving at least two lens groups of a focusing group. By moving at least five lens groups of a zoom group, different sizes of pictures can be obtained without changing the projection distance. A diaphragm is arranged in one of the lens groups of the zoom group, and the angle of light passing through the diaphragm is controlled when the at least five lens groups of the zoom group are moved, so that the change of the FNumber of the whole system before and after the movement is reduced, thereby reducing the change of the brightness of the projection picture during zooming. Through the cooperation of the lens groups, large-magnification continuous zooming can be realized, the imaging quality is high, the picture distortion is small, and the resolution is clear.

Description

Technical Field

[0001] This invention relates to the field of light projection technology, and in particular to a high-magnification continuous zoom projection optical system. Background Technology

[0002] Laser projection technology is a relatively new type of display projection technology currently on the market. Laser projectors using this technology can achieve automatic focusing; these are also called autofocus projectors. Focusing refers to adjusting the image distance of the projector by adjusting the position of its focal point.

[0003] A focusing projector includes a driving assembly and a projection lens, the projection lens comprising a focusing group for focusing. When the projection lens projects onto a screen, and the distance between the projection lens and the screen changes, the driving assembly can control each focusing lens in the focusing group to move along the optical axis of the focusing group according to a pre-configured correspondence between distance and image distance.

[0004] With the development of projection technology, the application scenarios of projectors are becoming increasingly diversified. When a large image needs to be projected from a short distance, users will choose a short-throw lens. However, traditional short-throw lenses are mainly fixed-focus, and different image sizes can only be achieved by changing the projection distance, which is difficult to meet the increasingly complex needs of users. In addition, the zoom ratio of traditional zoom projection lenses is mainly concentrated between 1.2x and 1.6x, and a single lens cannot meet the growing needs of users. Summary of the Invention

[0005] This invention provides a high-magnification continuous zoom projection optical system.

[0006] This invention provides the following solution:

[0007] A high-magnification continuous zoom projection optical system includes, along its optical axis, a focusing group, a zoom group, and a fixed group, sequentially arranged from the object side to the image side.

[0008] The focusing group includes at least a first lens group and a second lens group, both of which can move along the optical axis. At least one of the first lens group and the second lens group can be moved to obtain a clear image at different projection distances.

[0009] The zoom group includes at least a third lens group, a fourth lens group, a fifth lens group, a sixth lens group, and a seventh lens group, all of which can move along the optical axis; at least one of the third lens group, the fourth lens group, the fifth lens group, the sixth lens group, and the seventh lens group can be moved to obtain images of different sizes without changing the projection distance;

[0010] The fixed group includes at least one meniscus positive power lens;

[0011] The aperture stop is located in any one of the lens groups in the zoom group so that when the lens groups in the zoom group move, the angle of light passing through the aperture stop can be controlled, thereby reducing the change in the F-number of the entire system before and after the movement, and achieving the purpose of reducing the change in the brightness of the projected image during the zoom process.

[0012] Preferably, the first lens group has positive optical power, and the second lens group has negative optical power; the focal length f1 of the first lens group and the focal length f2 of the second lens group satisfy the following relationship: -0.4 <f2 / f1<-0.1。

[0013] Preferably, the first lens group includes a first lens and a second lens; the first lens is a biconvex positive power lens, and the second lens is a meniscus negative power lens;

[0014] The second lens group includes a third lens, a fourth lens, a fifth lens, and a sixth lens; the third lens is a meniscus negative power lens, the fourth lens is a biconcave negative power lens, the fifth lens is a biconcave negative power lens, and the sixth lens is a meniscus positive power lens.

[0015] Preferably, the minimum focal length fw obtained by moving at least five lens groups of the zoom group and the maximum focal length ft obtained by moving at least five lens groups of the zoom group satisfy the following relationship: 1.8 <ft / fw<2.2。

[0016] Preferably, the maximum aperture F#w obtained by moving at least five lens groups of the zoom group and the minimum aperture F#t obtained by moving at least five lens groups of the zoom group satisfy the following relationship: 1 <F#w / F#t<1.15。

[0017] Preferably, the minimum focal length fw obtained by moving at least five lens groups of the zoom group and the total length TTL of the entire optical system satisfy the following relationship: 0.08 <fw / TTL<0.12。

[0018] Preferably, the maximum field of view (FOV) obtained by moving at least five lens groups of the zoom group satisfies the following relationship: 40° <FOV<60°。

[0019] Preferably, the back focal length (FBL) of the optical system and the total length (TTL) of the entire optical projection system satisfy the following relationship: 0.2 <FBL / TTL<0.3。

[0020] Preferably, the third lens group includes a seventh lens; the seventh lens is a biconvex positive power lens.

[0021] The fourth lens group includes an eighth lens; the eighth lens is a meniscus positive power lens.

[0022] The fifth lens group includes a ninth lens; the ninth lens is a biconcave negative power lens;

[0023] The sixth lens group includes a tenth lens and an eleventh lens; the tenth lens with biconcave negative power and the eleventh lens with biconvex positive power form a cemented lens.

[0024] The seventh lens group includes a twelfth lens, a thirteenth lens, a fourteenth lens, a fifteenth lens, and a sixteenth lens; the twelfth lens with meniscus negative power, the thirteenth lens with biconvex positive power, and the fourteenth lens with meniscus negative power form a cemented three-layer lens; the fifteenth lens is a biconvex positive power lens; and the sixteenth lens is a meniscus positive power lens.

[0025] Preferably, the fixed group includes an eighth lens group, which includes a seventeenth lens; the seventeenth lens is a meniscus positive power lens.

[0026] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0027] This invention provides a high-magnification continuous zoom projection optical system. In one implementation, the system can achieve a clear image at different projection distances by moving at least two lens groups of a focusing group. By moving at least five lens groups of a zoom group, different image sizes can be obtained without changing the projection distance. The aperture stop is located in one of the lens groups of the zoom group. When the at least five lens groups of the zoom group move, they control the angle of light passing through the aperture stop, reducing the change in the F-number of the entire system before and after the movement, thereby reducing the change in the brightness of the projected image during the zoom process. Through the cooperation of the lens groups, high-magnification continuous zoom can be achieved while maintaining high image quality, low image distortion, and clear resolution.

[0028] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1This is a schematic diagram of the structure of a high-magnification continuous zoom projection optical system provided in an embodiment of the present invention;

[0031] Figure 2 These are schematic diagrams provided in embodiments of the present invention for focal lengths of 24mm and 48mm;

[0032] Figure 3 This is a schematic diagram of the MTF (Mean Transformer Format) provided in an embodiment of the present invention when the focal length is 24mm and the maximum field of view is 53°.

[0033] Figure 4 This is a distortion curve diagram provided in an embodiment of the present invention when the focal length is 24mm and the maximum field of view is 53°;

[0034] Figure 5 This is a schematic diagram of the MTF (Mean Transformer Format) provided in an embodiment of the present invention when the focal length is 48mm and the maximum field of view is 28°.

[0035] Figure 6 This is the distortion curve provided in the embodiment of the present invention when the focal length is 48mm and the maximum field of view is 28°. Detailed Implementation

[0036] 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. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0037] Example

[0038] See Figure 1 This invention provides a high-magnification continuous zoom projection optical system, such as... Figure 1 As shown, the system can include a focusing group, a zoom group, and a fixed group along its optical axis from the object side to the image side.

[0039] The focusing group includes at least a first lens group G1 and a second lens group G2, both of which can move along the optical axis. Moving at least one of the first lens group G1 and the second lens group G2 can obtain a clear image at different projection distances.

[0040] The zoom group includes at least a third lens group G3, a fourth lens group G4, a fifth lens group G5, a sixth lens group G6, and a seventh lens group G7, all of which can move along the optical axis. Moving at least one of the third lens group G3, the fourth lens group G4, the fifth lens group G5, the sixth lens group G6, and the seventh lens group G7 allows for obtaining images of different sizes without changing the projection distance.

[0041] The fixed group includes at least one meniscus positive power lens;

[0042] The aperture stop S is located in any one of the lens groups in the zoom group so that when the lens groups in the zoom group move, the angle of light passing through the aperture stop S can be controlled, thereby reducing the change in the F Number of the entire system before and after the movement, and achieving the purpose of reducing the change in the brightness of the projected image during the zoom process.

[0043] The high-magnification continuous zoom projection optical system provided in this application includes a focusing group containing at least two movable lens groups. By moving these at least two lens groups, a clear image can be obtained at different projection distances. The zoom group contains at least five movable zoom lens groups. The function of these lens groups is to obtain images of different sizes without changing the projection distance by moving these at least five lens groups. Furthermore, an aperture stop is located in one of the lens groups (in the figure, the aperture stop is set in the sixth lens group G6). The function of this lens group is to control the angle of light passing through the aperture stop when the at least five lens groups are moved, reducing the change in the overall system F-number (focal length value, aperture number used to express the relationship between the lens's focal length (mm) and aperture diameter (mm)) before and after the movement, thereby reducing the change in the brightness of the projected image during the zoom process. The adjustment process is as follows: Figure 2 As shown.

[0044] In specific implementation, to achieve the functions of each group, the embodiments of this application can provide that the first lens group G1 has positive optical power and the second lens group G2 has negative optical power; the focal length f1 of the first lens group G1 and the focal length f2 of the second lens group G2 satisfy the following relationship: -0.4 <f2 / f1<-0.1。

[0045] Furthermore, the first lens group G1 includes a first lens L1 and a second lens L2; ​​the first lens L1 is a biconvex positive power lens, and the second lens L2 is a meniscus negative power lens.

[0046] The second lens group G2 includes a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6; the third lens L3 is a meniscus negative power lens, the fourth lens L4 is a biconcave negative power lens, the fifth lens L5 is a biconcave negative power lens, and the sixth lens L6 is a meniscus positive power lens.

[0047] The minimum focal length fw obtained by moving at least five lens groups of the zoom group and the maximum focal length ft obtained by moving at least five lens groups of the zoom group satisfy the following relationship: 1.8 <ft / fw<2.2。

[0048] The maximum aperture F#w obtained by moving at least five lens groups of the zoom group and the minimum aperture F#t obtained by moving at least five lens groups of the zoom group satisfy the following relationship: 1 <F#w / F#t<1.15。

[0049] The minimum focal length fw obtained by moving at least five lens groups of the zoom group and the total length TTL of the entire optical system satisfy the following relationship: 0.08 <fw / TTL<0.12。

[0050] The maximum field of view (FOV) obtained by moving at least five lens groups of the zoom group satisfies the following relationship: 40° <FOV<60°。

[0051] The back focal length (FBL) of the optical system and the total length (TTL) of the entire optical projection system satisfy the following relationship: 0.2 <FBL / TTL<0.3。

[0052] The third lens group G3 includes a seventh lens L7; the seventh lens L7 is a biconvex positive power lens.

[0053] The fourth lens group G4 includes an eighth lens L8; the eighth lens L8 is a meniscus positive power lens.

[0054] The fifth lens group G5 includes a ninth lens L9; the ninth lens L9 is a biconcave negative power lens;

[0055] The sixth lens group G6 includes a tenth lens L10 and an eleventh lens L11; the tenth lens L10 with biconcave negative power and the eleventh lens L11 with biconvex positive power form a cemented lens.

[0056] The seventh lens group G7 includes a twelfth lens L12, a thirteenth lens L13, a fourteenth lens L14, a fifteenth lens L15, and a sixteenth lens L16; the twelfth lens L12 with meniscus negative power, the thirteenth lens L13 with biconvex positive power, and the fourteenth lens L14 with meniscus negative power form a cemented three-layer lens; the fifteenth lens L15 is a biconvex positive power lens; and the sixteenth lens L16 is a meniscus positive power lens.

[0057] The fixed group includes an eighth lens group G8, which includes a seventeenth lens L17; the seventeenth lens L17 is a meniscus positive power lens.

[0058] The system provided in the embodiments of this application will be described in detail below.

[0059] The system consists of a focusing group, a zoom group, and a fixed group, arranged sequentially from the object side to the image side. The focusing group contains two lens groups, G1 and G2, and these two lens groups are movable. The zoom group contains five lens groups, G3 to G7, and these five lens groups are movable. The fixed group contains an eighth lens group, G8.

[0060] The first lens group G1 includes a first lens L1 and a second lens L2, wherein the first lens L1 is a biconvex positive power lens and the second lens L2 is a meniscus negative power lens.

[0061] The second lens group G2 includes the third lens L3 to the sixth lens L6, wherein the third lens L3 is a meniscus negative power lens, the fourth lens L4 is a biconcave negative power lens, the fifth lens L5 is a biconcave negative power lens, and the sixth lens L6 is a meniscus positive power lens.

[0062] The third lens group G3 includes the seventh lens L7, which is a biconvex positive power lens.

[0063] The fourth lens group G4 includes the eighth lens L8, which is a meniscus positive power lens.

[0064] The fifth lens group G5 includes the ninth lens L9, which is a biconcave negative power lens.

[0065] The sixth lens group G6 includes the tenth lens L10 and the eleventh lens L11, wherein the tenth lens L10, which is biconcave and has a negative optical power, and the eleventh lens L11, which is biconvex and has a positive optical power, form a cemented lens. The aperture stop S can be located in the sixth lens group G6.

[0066] The seventh lens group G7 includes the twelfth lens L12 to the sixteenth lens L16. The twelfth lens L12 with meniscus negative power, the thirteenth lens L13 with biconvex positive power, and the fourteenth lens L14 with meniscus negative power form a triplet lens. The fifteenth lens L15 is a biconvex positive power lens, and the sixteenth lens L16 is a meniscus positive power lens.

[0067] The eighth lens group G8 includes the seventeenth lens L17, which is a meniscus positive power lens.

[0068] The verification results are as follows Figure 3 , Figure 4 , Figure 5 , Figure 6As shown. The system proposed in this application embodiment can achieve a 2x continuous zoom system by moving the five lens groups of the zoom group, with a minimum focal length of 24mm (corresponding to a maximum field of view of 53°) and a maximum focal length of 48mm (corresponding to a maximum field of view of 28°).

[0069] Optical data are shown in Table 1.

[0070] Table 1

[0071]

[0072]

[0073] Where R represents the radius of curvature of the lens, d represents the lens thickness or air gap, nd represents the refractive index of the glass, and vd represents the Abbe number of the glass. Air gap data from D0 to D5 are shown in Table 2.

[0074] Table 2

[0075]

[0076]

[0077] Table 2 shows the changes in air gap between zoom groups at different focal lengths, achieving a 2x zoom.

[0078] In summary, the high-magnification continuous zoom projection optical system provided in this application can obtain a clear image at different projection distances by moving at least two lens groups of the focusing group. By moving at least five lens groups of the zoom group, different image sizes can be obtained without changing the projection distance. The aperture stop is located in one of the lens groups of the zoom group. When the at least five lens groups of the zoom group move, they control the angle of light passing through the aperture stop, reducing the change in the F-number of the entire system before and after the movement, thereby reducing the change in the brightness of the projected image during the zoom process. Through the cooperation of the various lens groups, high-magnification continuous zoom can be achieved while maintaining high image quality, low image distortion, and clear resolution.

[0079] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0080] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A high-magnification continuous zoom projection optical system, characterized in that, It sequentially includes a focusing lens group, a zoom lens group, and a fixed lens group from the object side to the image side along its optical axis direction; the number of lens elements with optical power in the projection optical system is 17. The focusing lens group at least includes a first lens group and a second lens group that can both move along the optical axis direction. Move at least one of the first lens group and the second lens group to obtain a clear image at different projection distances. The first lens group has a positive optical power, and the second lens group has a negative optical power; the focal length f1 of the first lens group and the focal length f2 of the second lens group satisfy the following relationship: -0.4 < f2 / f1 < -0.1; the first lens group includes a first lens and a second lens; the first lens is a biconvex positive optical power lens, and the second lens is a meniscus negative optical power lens. The second lens group includes a third lens, a fourth lens, a fifth lens, and a sixth lens; the third lens is a meniscus negative optical power lens, the fourth lens is a biconcave negative optical power lens, the fifth lens is a biconcave negative optical power lens, and the sixth lens is a meniscus positive optical power lens. The zoom lens group at least includes a third lens group, a fourth lens group, a fifth lens group, a sixth lens group, and a seventh lens group that can all move along the optical axis direction. Move at least one of the third lens group, the fourth lens group, the fifth lens group, the sixth lens group, and the seventh lens group to obtain images of different sizes without changing the projection distance; the third lens group includes a seventh lens; the seventh lens is a biconvex positive optical power lens. The fourth lens group includes an eighth lens; the eighth lens is a meniscus positive optical power lens. The fifth lens group includes a ninth lens; the ninth lens is a biconcave negative optical power lens. The sixth lens group includes a tenth lens and an eleventh lens; the tenth lens with biconcave negative optical power and the eleventh lens with biconvex positive optical power form a cemented lens. The seventh lens group includes a twelfth lens, a thirteenth lens, a fourteenth lens, a fifteenth lens, and a sixteenth lens; the twelfth lens with meniscus negative optical power, the thirteenth lens with biconvex positive optical power, and the fourteenth lens with meniscus negative optical power form a triple cemented lens, the fifteenth lens is a biconvex positive optical power lens, and the sixteenth lens is a meniscus positive optical power lens. The fixed lens group at least includes a meniscus positive optical power lens; the fixed lens group includes an eighth lens group, and the eighth lens group includes a seventeenth lens. The seventeenth lens is a meniscus positive optical power lens. Wherein, the aperture stop is located in any one of the lens groups in the zoom lens group, so as to control the angle of the light passing through the aperture stop when the lens groups in the zoom lens group move, reduce the change of the overall system F Number before and after the movement, and achieve the purpose of reducing the change of the projection image brightness during the zoom process.

2. The high-magnification continuous zoom projection optical system according to claim 1, characterized in that, The minimum focal length fw obtained by moving at least five lens groups of the zoom group and the maximum focal length ft obtained by moving at least five lens groups of the zoom group satisfy the following relationship: 1.8 <ft / fw<2.2。 3. The high-magnification continuous zoom projection optical system according to claim 1, characterized in that, The maximum aperture F#w obtained by moving at least five lens groups of the zoom group and the minimum aperture F#t obtained by moving at least five lens groups of the zoom group satisfy the following relationship: 1 <F#w / F#t<1.15。 4. The high-magnification continuous zoom projection optical system according to claim 1, characterized in that, The minimum focal length fw obtained by moving at least five lens groups of the zoom group and the total length TTL of the entire optical system satisfy the following relationship: 0.08 <fw / TTL<0.12。 5. The high-magnification continuous zoom projection optical system according to claim 1, characterized in that, The maximum field of view (FOV) obtained by moving at least five lens groups of the zoom group satisfies the following relationship: 40° <FOV<60°。 6. The high-magnification continuous zoom projection optical system according to claim 1, characterized in that, The back focal length (FBL) of the optical system and the total length (TTL) of the entire optical projection system satisfy the following relationship: 0.2 <FBL / TTL<0.3。

Images