Optical system, image projection device, and image pickup device

Abstract

The present disclosure relates to an optical system, an image projection apparatus, and an image pickup apparatus, the optical system having an intermediate imaging position (MI) internally conjugated to a magnification conjugate point on a magnification side and a reduction conjugate point on a reduction side, and including: a magnification optical system (Op) having a plurality of lens elements (L1 to L15) located on a magnification side of the intermediate imaging position (MI); and a relay optical system (Ol) having a plurality of lens elements (L16 to L28) located on a reduction side of the intermediate imaging position (MI). The magnification optical system (Op) is fixed with respect to the reduction conjugate point at the time of zooming. The relay optical system (Ol) includes a plurality of movable lens groups (G2 to G5) that are independently movable in an optical axis direction at the time of zooming. A most reduction side movable lens group (G5) located on the most reduction side among the plurality of movable lens groups has a negative refractive power.

Description

Technical Field

[0001] This disclosure relates to an optical system for forming an intermediate image. Furthermore, this disclosure relates to an image projection device and a camera device using such an optical system. Background Technology

[0002] Intermediate imaging optical systems have the advantage of achieving wide-angle projection of large images with short focal points, but they tend to increase the overall length of the optical system. As a result, the optical system becomes heavier, and when part of the optical system is mounted outside the housing of the image projection device, the torque acting on the center of gravity may cause the optical system to tilt relative to the device body, thus reducing optical performance.

[0003] Patent document 1 discloses a wide-angle imaging optical system in which the first lens L1a, closest to the magnification conjugate point, has the largest aperture. Both surfaces of the first lens L1a are aspherical, resulting in a very complex shape.

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-174633 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] This disclosure provides an optical system that enables wide-angle lenses, reduced effective lens diameter, and miniaturization and weight reduction of the optical system and zoom mechanism. Furthermore, this disclosure provides an image projection device and a camera device using such an optical system.

[0009] Methods for solving problems

[0010] The lens system disclosed herein is an optical system having an intermediate imaging position internally conjugate to both a magnification conjugate point on the magnification side and a reduction conjugate point on the reduction side. It comprises: a magnifying optical system having multiple lens elements located closer to the magnification side than the intermediate imaging position; and a relay optical system having multiple lens elements located closer to the reduction side than the intermediate imaging position. The magnifying optical system is fixed relative to the reduction conjugate point during zooming. The relay optical system includes multiple movable lens groups capable of independently moving along the optical axis during zooming. Among the multiple movable lens groups, the smallest reduction-side movable lens group located closest to the reduction side has a negative refractive power.

[0011] Furthermore, the image projection apparatus disclosed herein includes: the aforementioned optical system; and an image forming element, which generates an image projected onto a screen via the optical system.

[0012] Furthermore, the camera device disclosed herein includes: the aforementioned optical system; and a camera element that receives the optical image formed by the optical system and converts it into an electronic image signal.

[0013] Invention Effects

[0014] According to the lens system disclosed herein, it is possible to achieve wide-angle lenses, reduce the effective diameter of lenses, and miniaturize and lighten the optical system and zoom mechanism. Attached Figure Description

[0015] Figure 1 This is a diagram showing the optical path configuration at the wide-angle end of the zoom lens system of Embodiment 1 at an object distance of 1100 mm.

[0016] Figure 2 This is a configuration diagram of the wide-angle end of the zoom lens system of Embodiment 1 at an object distance of 1100mm.

[0017] Figure 3 This is a longitudinal aberration diagram of the zoom lens system of Example 1 at an object distance of 1100mm.

[0018] Figure 4 This is a longitudinal aberration diagram at object distances of 710mm and 762mm for the zoom lens system of Example 1.

[0019] Figure 5 This is a longitudinal aberration diagram at object distances of 2842mm and 3048mm for the zoom lens system of Example 1.

[0020] Figure 6 This is a diagram showing the optical path configuration at the wide-angle end of the zoom lens system of Embodiment 2 at an object distance of 1100 mm.

[0021] Figure 7 This is a configuration diagram of the wide-angle end of the zoom lens system in Example 2 at an object distance of 1100mm.

[0022] Figure 8 This is a longitudinal aberration diagram of the zoom lens system of Example 2 at an object distance of 1100mm.

[0023] Figure 9 This is a longitudinal aberration diagram of the zoom lens system of Example 2 at object distances of 710mm and 762mm.

[0024] Figure 10 This is a longitudinal aberration diagram of the zoom lens system of Example 2 at object distances of 2842mm and 3048mm.

[0025] Figure 11 This is a diagram showing the optical path configuration at the wide-angle end of the zoom lens system of Embodiment 3 at an object distance of 1100mm.

[0026] Figure 12 This is a configuration diagram of the wide-angle end of the zoom lens system of Example 3 at an object distance of 1100mm.

[0027] Figure 13 This is a longitudinal aberration diagram of the zoom lens system of Example 3 at an object distance of 1100mm.

[0028] Figure 14 This is a longitudinal aberration diagram at object distances of 710mm and 762mm for the zoom lens system of Example 3.

[0029] Figure 15 This is a longitudinal aberration diagram at object distances of 2842mm and 3048mm for the zoom lens system of Example 3.

[0030] Figure 16 This is a diagram showing the optical path configuration at the wide-angle end of the zoom lens system of Embodiment 4 at an object distance of 1100 mm.

[0031] Figure 17 This is a configuration diagram of the wide-angle end of the zoom lens system of Example 4 at an object distance of 1100mm.

[0032] Figure 18 This is a longitudinal aberration diagram of the zoom lens system of Example 4 at an object distance of 1100mm.

[0033] Figure 19 This is a longitudinal aberration diagram at object distances of 710mm and 762mm for the zoom lens system of Example 4.

[0034] Figure 20 This is a longitudinal aberration diagram of the zoom lens system of Example 4 at object distances of 2842mm and 3048mm.

[0035] Figure 21 This is a diagram showing the optical path configuration at the wide-angle end of the zoom lens system of Embodiment 5 at an object distance of 1100 mm.

[0036] Figure 22 This is a configuration diagram of the wide-angle end of the zoom lens system of Example 5 at an object distance of 1100mm.

[0037] Figure 23 This is a longitudinal aberration diagram of the zoom lens system of Example 5 at an object distance of 1100mm.

[0038] Figure 24 This is a longitudinal aberration diagram at object distances of 710mm and 762mm for the zoom lens system of Example 5.

[0039] Figure 25 This is a longitudinal aberration diagram of the zoom lens system of Example 5 at object distances of 2842mm and 3048mm.

[0040] Figure 26 This is a block diagram illustrating an example of an image projection apparatus related to this disclosure.

[0041] Figure 27 This is a block diagram illustrating an example of a camera device involved in this disclosure. Detailed Implementation

[0042] The following is a brief reference to the appendix. Figure 1 The embodiments will be described in detail. However, sometimes unnecessary details are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of substantially the same structures are sometimes omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art.

[0043] Furthermore, the applicant has provided the accompanying drawings and the following description in order to enable those skilled in the art to fully understand this disclosure, but it is not intended to limit the subject matter described in the patent claim.

[0044] Hereinafter, various embodiments of the optical system disclosed herein will be described. In each embodiment, the optical system will be described as being used in a projector (an example of an image projection device) that projects an image light of an original image S obtained by spatially modulating incident light based on an image signal using an image forming element such as a liquid crystal or a DMD (digital micromirror device) onto a screen. That is, the optical system disclosed herein can be used to enlarge and project an original image S disposed on an image forming element disposed on a reduction side onto a screen by arranging a screen (not shown) on the extension line of the magnification side.

[0045] Furthermore, the optical system disclosed herein can also be used to focus light emitted from an object located on the extension line of the magnification side, and form an optical image of the object on the imaging surface of the imaging element disposed on the reduction side.

[0046] (Implementation Method 1)

[0047] The following uses Figures 1 to 25 Embodiment 1 of this disclosure will be described. Here, a zoom lens system will be described as an example of an optical system.

[0048] Figure 1 , 6 11, 16, and 21 are optical path configuration diagrams showing the wide-angle end of the zoom lens system according to Embodiments 1 to 5 at an object distance of 1100 mm. Figure 2 , 7 Figures 1, 12, 17, and 22 are configuration diagrams of the wide-angle end of the zoom lens system involved in Examples 1 to 5 at an object distance of 1100 mm. Figure 2 of (a), Figure 7 of (a), Figure 12 of (a), Figure 17 of (a), Figure 22 (a) shows the lens configuration at the wide-angle end of the zoom lens system. Figure 2 (b) Figure 7 (b) Figure 12 (b) Figure 17 (b) Figure 22 (b) shows the lens configuration at the middle position of the zoom lens system. Figure 2 (c) Figure 7 (c) Figure 12 (c) Figure 17 (c) Figure 22 (c) shows the lens configuration at the telephoto end of the zoom lens system.

[0049] The wide-angle end represents the shortest focal length (fw) of the entire system. The intermediate position represents the focal length between the wide-angle and telephoto ends. The telephoto end represents the longest focal length (ft) of the entire system. The focal length of the intermediate position is defined based on the focal lengths (fw) of the wide-angle and telephoto ends.

[0050] The zoom lens systems described in Examples 1-5 have an intermediate imaging position MI internally, which is conjugate to both the magnification conjugate point on the magnification side and the reduction conjugate point on the reduction side. A magnifying optical system Op is positioned further along the magnification side than the intermediate imaging position MI, and a relay optical system Ol is positioned further along the reduction side than the intermediate imaging position MI. An optical element P is positioned further along the reduction side than the relay optical system Ol.

[0051] In Embodiment 1, the magnifying optical system Op is composed of the first lens element L1 to the 15th lens element L15, including surfaces 1 to 30 (surface numbers refer to the numerical embodiments described later).

[0052] In Embodiment 1, the relay optical system Ol includes a first lens group G1 to a sixth lens group G6. The first lens group G1 has positive optical power and is composed of a 16th lens element L16, including surfaces 31 to 32. The second lens group G2 has negative optical power and is composed of a 17th lens element L17, including surfaces 33 to 34. The third lens group G3 has positive optical power and is composed of an 18th lens element L18, including surfaces 35 to 36. The fourth lens group G4 has positive optical power and is composed of a 19th lens element L19 to a 21st lens element L21, including surfaces 37 to 42. The fifth lens group G5 has negative optical power and is composed of a 22nd lens element L22 to a 23rd lens element L23, including surfaces 43 to 47. The sixth lens group G6 has positive optical power and is composed of a 24th lens element L24 to a 28th lens element L28, including surfaces 48 to 57. Optical element P includes surfaces 58 to 59.

[0053] In embodiments 2 to 5, the magnifying optical system Op is composed of the first lens element L1 to the fourteenth lens element L14, including surfaces 1 to 28.

[0054] In embodiments 2-5, the relay optical system O1 includes a first lens group G1 to a sixth lens group G6. The first lens group G1 has positive optical power and is composed of a 15th lens element L15, including surfaces 29 to 30. The second lens group G2 has negative optical power and is composed of a 16th lens element L16, including surfaces 31 to 32. The third lens group G3 has positive optical power and is composed of a 17th lens element L17, including surfaces 33 to 34. The fourth lens group G4 has positive optical power and is composed of a 18th lens element L18 to a 20th lens element L20, including surfaces 35 to 40. The fifth lens group G5 has negative optical power and is composed of a 21st lens element L21 to a 22nd lens element L22, including surfaces 41 to 45. The sixth lens group G6 has positive optical power and is composed of lens elements L23 to L27, including surfaces 468 to 55. Optical element P includes surfaces 56 to 61.

[0055] The arrows on the broken lines shown between Figures (a) and (b) are straight lines drawn from the top of the figures, connecting the positions of the first lens group G1 to the sixth lens group G6 in the wide-angle, intermediate, and telephoto positions, respectively. The connections between the wide-angle and intermediate positions, and between the intermediate and telephoto positions, are simply straight lines, unlike the actual movement of each lens group G1 to G6. Furthermore, the symbols (+) and (-) for each lens group G1 to G6 indicate the sign of its optical power.

[0056] The zoom lens systems described in Examples 1-5 may, as needed, include a focusing lens group for focusing adjustment when the object distance changes, and an image plane curvature correction lens group for correcting image plane curvature aberration after focusing adjustment by the focusing lens group. As an example, the zoom lens system described in Example 1 includes a first focusing lens group FG1 composed of lens elements L12 to L15, and a second focusing lens group FG2 composed of lens element L16. The zoom lens systems described in Examples 2-5 include a first focusing lens group FG1 composed of lens elements L11 to L14, and a second focusing lens group FG2 composed of lens element L15. Such a first focusing lens group FG1 and a second focusing lens group FG2 can move independently along the optical axis during focusing.

[0057] In each figure, the imaging position on the magnified side (i.e., the magnified conjugate point) is located on the left, and the imaging position on the reduced side (i.e., the reduced conjugate point) is located on the right. Furthermore, in each figure, the straight line drawn closest to the reduced side represents the position of the original image S, with optical element P located on the magnified side of the original image S. Optical element P represents optical elements such as prisms for color decomposition and color synthesis, optical filters, parallel plate glass, quartz low-pass filters, and infrared cutoff filters.

[0058] In the zoom lens system of Embodiment 1, there are multiple air gaps between the first lens element L1 to the 28th lens element L28 and the optical element P. In the zoom lens systems of Embodiments 2-5, there are multiple air gaps between the first lens element L1 to the 27th lens element L27 and the optical element P. The magnifying optical system Op has the longest air gap along the optical axis within the magnifying optical system. For example, in Embodiment 1, as... Figure 2 As shown, the longest air gap exists between the 11th lens element L11 and the 12th lens element L12. In embodiments 2-5, as... Figure 7 , 12 As shown in Figures 17 and 22, the longest air gap exists between the 10th lens element L10 and the 11th lens element L11. The magnifying optical system Op has a front group Opf located on the magnification side, which is located further away from the longest air gap, and a rear group Opr located on the reduction side, which is located further away from the longest air gap. The front group Opf and the rear group Opr may have one or more lens elements.

[0059] Figure 3 , 8 13, 18, and 23 are longitudinal aberration diagrams at an object distance of 1100 mm for the zoom lens systems involved in Examples 1 to 5. Figure 4 , 914, 19, and 24 are longitudinal aberration diagrams at object distances of 710 mm and 762 mm for the zoom lens systems involved in Examples 1 to 5. Figure 5 , 10 Figures 15, 20, and 25 are longitudinal aberration diagrams at object distances of 2842 mm and 3048 mm for the zoom lens systems involved in Examples 1 to 5. Figures (a), (b), and (c) show the longitudinal aberration diagrams at the wide-angle end, intermediate position, and telephoto end of the zoom lens system.

[0060] The aberration diagrams, from left to right, show spherical aberration (SA (mm)), astigmatism (AST (mm)), and distortion aberration (DIS (%)). In the spherical aberration diagram, the vertical axis represents the pupil height; solid lines represent the characteristics of the d-line, short dashed lines represent the characteristics of the F-line, and long dashed lines represent the characteristics of the C-line. In the astigmatism diagram, the vertical axis represents the image height; solid lines represent the characteristics of the sagittal plane (represented by 's' in the diagram), and dashed lines represent the characteristics of the meridional plane (represented by 'm' in the diagram). In the distortion aberration diagram, the vertical axis represents the image height. Furthermore, distortion aberration represents the distortion aberration relative to equidistant projection.

[0061] (Example 1)

[0062] like Figure 1 , 2 As shown, the zoom lens system according to Embodiment 1 includes a magnifying optical system Op and a relay optical system Ol. The magnifying optical system Op is composed of a first lens element L1 to a fifteenth lens element L15. The magnifying optical system Op includes a front group Opf and a rear group Opr.

[0063] The front group Opf of the magnifying optical system Op is composed of lens elements L1 to L11, arranged sequentially from the magnifying side to the reducing side. Lens element L1 has a negative meniscus shape with its convex surface facing the magnifying side. Lens element L2 has a negative meniscus shape with its convex surface facing the magnifying side. Lens element L3 has a negative meniscus shape with its convex surface facing the magnifying side. Lens element L4 has a biconcave shape. Lens element L5 has a biconvex shape. Lens element L6 has a positive meniscus shape with its convex surface facing the reducing side. Lens element L7 has a positive meniscus shape with its convex surface facing the reducing side. Lens element L8 has a biconcave shape. Lens element L9 has a positive meniscus shape with its convex surface facing the reducing side. Lens element L10 has a biconvex shape. Lens element L11 has a negative meniscus shape with its convex surface facing the magnifying side.

[0064] The rear group Opr of the magnifying optical system Op is composed of lens elements L12 to L15, arranged sequentially from the magnifying side to the reducing side. Lens element L12 has a biconvex shape. Lens element L13 has a positive meniscus shape with its convex surface facing the magnifying side. Lens element L14 has a positive meniscus shape with its convex surface facing the magnifying side. Lens element L15 has a negative meniscus shape with its convex surface facing the magnifying side.

[0065] The relay optical system Ol is composed of lens elements L16 to L28, arranged sequentially from the magnification side to the reduction side. Lens element L16 has a negative meniscus shape with its convex surface facing the reduction side. Lens element L17 has a biconcave shape. Lens element L18 has a positive meniscus shape with its convex surface facing the reduction side. Lens element L19 has a biconvex shape. Lens element L20 has a negative meniscus shape with its convex surface facing the reduction side. Lens element L21 has a biconvex shape. Lens element L22 has a positive meniscus shape with its convex surface facing the magnification side. Lens element L23 has a negative meniscus shape with its convex surface facing the magnification side. Lens element L24 has a biconcave shape. Lens element L25 has a biconvex shape. Lens element L26 has a biconvex shape. Lens element L27 has a negative meniscus shape with its convex surface facing the magnification side. Lens element L28, number 28, has a biconvex shape.

[0066] The relay optical system Op consists of, from the magnification side to the reduction side, a first lens group G1 (L16) with positive optical power, a second lens group G2 (L17) with negative optical power, a third lens group G3 (L18) with positive optical power, a fourth lens group G4 (L19-L21) with positive optical power, a fifth lens group G5 (L22-L23) with negative optical power, and a sixth lens group G6 (L24-L28) with positive optical power. During zooming, the magnification optical system Op and the sixth lens group G6 are fixed relative to the reduction conjugate point. Furthermore, the first lens group G1 through the fifth lens group G5 can be independently shifted along the optical axis, or at least one of the first lens groups G1 through the fifth lens group G5 can be fixed relative to the reduction conjugate point.

[0067] An intermediate imaging position MI is located between lens element L15 (15th lens element) and lens element L16 (16th lens element). Furthermore, an aperture stop A is positioned between lens element L22 (22nd lens element) and lens element L23 (23rd lens element). An optical element P with zero optical power is positioned on the reduced side of the relay optical system Ol.

[0068] (Examples 2-5)

[0069] like Figure 6 , 7As shown in 11, 12, 16, 17, 21, and 22, the zoom lens systems involved in Examples 2 to 5 include a magnifying optical system Op and a relay optical system Ol. The magnifying optical system Op is composed of a first lens element L1 to a fourteenth lens element L14. The magnifying optical system Op includes a front group Opf and a rear group Opr.

[0070] The front group Opf of the magnifying optical system Op is composed of lens elements L1 to L10, arranged sequentially from the magnifying side to the reducing side. Lens element L1 has a negative meniscus shape with its convex surface facing the magnifying side. Lens element L2 has a negative meniscus shape with its convex surface facing the magnifying side. Lens element L3 has a negative meniscus shape with its convex surface facing the magnifying side. Lens element L4 has a biconcave shape. Lens element L5 has a biconvex shape. Lens element L6 has a positive meniscus shape with its convex surface facing the reducing side. Lens element L7 has a positive meniscus shape with its convex surface facing the reducing side. Lens element L8 has a biconcave shape. Lens element L9 has a biconvex shape. Lens element L10 has a biconvex shape.

[0071] The rear group Opr of the magnifying optical system Op is composed of lens elements L11 to L14, arranged sequentially from the magnifying side to the reducing side. Lens element L11 has a biconvex shape. Lens element L12 has a positive meniscus shape with its convex surface facing the magnifying side. Lens element L13 has a positive meniscus shape with its convex surface facing the magnifying side. Lens element L14 has a negative meniscus shape with its convex surface facing the magnifying side.

[0072] The relay optical system Ol is composed of lens elements L15 (15th) to L27 (27th) sequentially from the magnification side to the reduction side. Lens element L15 has a positive meniscus shape with its convex surface facing the reduction side. Lens element L16 has a biconcave shape. Lens element L17 has a positive meniscus shape with its convex surface facing the reduction side. Lens element L18 has a biconvex shape. Lens element L19 has a negative meniscus shape with its convex surface facing the reduction side. Lens element L20 has a biconvex shape. Lens element L21 has a positive meniscus shape with its convex surface facing the magnification side. Lens element L22 has a negative meniscus shape with its convex surface facing the magnification side. Lens element L23 has a biconcave shape. Lens element L24 has a biconvex shape. Lens element L25 has a biconvex shape. Lens element L26 has a negative meniscus shape with its convex surface facing the magnification side. Lens element L27 has a biconvex shape.

[0073] The relay optical system Op consists of, from the magnification side to the reduction side, a first lens group G1 (L15) with positive optical power, a second lens group G2 (L16) with negative optical power, a third lens group G3 (L17) with positive optical power, a fourth lens group G4 (L18-L20) with positive optical power, a fifth lens group G5 (L21-L22) with negative optical power, and a sixth lens group G6 (L23-L27) with positive optical power. During zooming, the magnification optical system Op and the sixth lens group G6 are fixed relative to the reduction conjugate point. Furthermore, the first lens group G1 through the fifth lens group G5 can be independently shifted along the optical axis, or at least one of the first lens groups G1 through the fifth lens group G5 can be fixed relative to the reduction conjugate point.

[0074] An intermediate imaging position MI is located between the 14th lens element L14 and the 15th lens element L15. Furthermore, an aperture stop A is positioned between the 21st lens element L21 and the 22nd lens element L22. An optical element P with zero optical power is positioned on the reduced side of the relay optical system Ol.

[0075] In addition, the zoom lens system involved in Examples 1 to 5 may include not only lens elements with optical power, but also elements with zero or substantially zero optical power, such as mirrors, apertures, light shields, glass covers, filters, prisms, wavelength plates, polarizing elements and other optical elements.

[0076] Next, the conditions that the zoom lens system according to this embodiment can satisfy will be explained. Furthermore, multiple conditions are specified for the zoom lens system according to each embodiment; however, all of these conditions can be satisfied, or individual conditions can be satisfied to obtain the corresponding effect.

[0077] The zoom lens system described in Examples 1-5 is an optical system having an intermediate imaging position internally conjugate to both the magnification conjugate point on the magnification side and the reduction conjugate point on the reduction side. It comprises: a magnification optical system having multiple lens elements located closer to the magnification side than the intermediate imaging position; and a relay optical system having multiple lens elements located closer to the reduction side than the intermediate imaging position. The magnification optical system is fixed relative to the reduction conjugate point during zooming. The relay optical system includes multiple movable lens groups capable of moving independently along the optical axis during zooming. Among the multiple movable lens groups, the smallest reduction-side movable lens group located closest to the reduction side has a negative refractive power.

[0078] As an example, in embodiments 1 to 5, during zooming, the second lens group G2 to the fifth lens group G5 can move independently along the optical axis, and the fifth lens group G5 has a negative refractive power.

[0079] With this structure, even with a wide-angle lens, the effective diameter of the lens can be reduced. Therefore, it is possible to achieve lightweighting of the optical system and its components.

[0080] Furthermore, zooming can be performed without moving the magnifying optical system, which tends to increase in size and weight, thus enabling the miniaturization and weight reduction of the zoom mechanism.

[0081] Furthermore, by employing a structure where the smallest moving lens group among multiple moving lens groups has negative refractive power, the amount of movement during zooming can be reduced, and the effective diameter of the lens can be further reduced, thus enabling miniaturization. Moreover, the moving lens group with negative refractive power can correct for image plane curvature and astigmatism caused by the intermediate imaging structure, achieving high performance.

[0082] Furthermore, in the zoom lens systems described in Examples 1 to 5, the minimized-side moving lens group can also be moved toward the minimized side when zooming from the wide-angle end to the telephoto end.

[0083] As an example, in embodiments 1 to 5, when zooming from the wide-angle end to the telephoto end, the fifth lens group G5 moves towards the reduction side.

[0084] Based on this structure, aberration variations can be reduced during zooming, resulting in good performance across the entire zoom range.

[0085] Furthermore, the zoom lens systems involved in Examples 1 to 5 can also satisfy the following condition (1).

[0086] 0.01 < CTN / Ymax < 1.0 (1)

[0087] Here,

[0088] CTN: The amount of movement of the lens group on the smallest side during zooming;

[0089] Ymax: Effective image circle diameter on the narrowed side.

[0090] Condition (1) is a conditional expression used to define the relationship between the amount of movement of the minimized-side moving lens group and the effective image circle diameter on the minimized side. By satisfying condition (1), a wide-angle and compact lens system can be achieved. If the movement is below the lower limit of condition (1), the amount of movement of the minimized-side moving lens group becomes too small, making it difficult to correct for image plane curvature and astigmatism. If the movement exceeds the upper limit of condition (1), the amount of movement of the minimized-side moving lens group becomes large, the overall length of the lens becomes longer, and miniaturization becomes difficult.

[0091] Furthermore, based on condition (1), even more favorable results can be obtained by further satisfying the following condition (1A).

[0092] 0.02 < CTN / Ymax < 0.90 (1A)

[0093] Furthermore, in the zoom lens system described in Examples 1 to 5, the relay optical system may include a minimum-minimum fixed lens group that is fixed relative to the minimum conjugate point and located on the minimum-minimum side during zooming, and the minimum-minimum fixed lens group has positive refractive power.

[0094] As an example, in embodiments 1 to 5, the sixth lens group G6, which has positive refractive power, can also be fixed relative to the conjugate point of reduction during zooming.

[0095] With this structure, the fixed lens group on the smallest side has positive refractive power, which can maintain telecentrism and reduce aberration changes during zooming.

[0096] Furthermore, in the zoom lens systems described in Examples 1 to 5, the relay optical system may also include a fixed lens group on the magnification side that is fixed relative to the reduction conjugate point and located on the magnification side during zooming.

[0097] As an example, in embodiments 1 to 5, the first lens group G1 can also be fixed relative to the reduction conjugate point during zooming.

[0098] This structure reduces aberrations during zooming. Furthermore, it simplifies the design of the zoom lens system.

[0099] Furthermore, in the zoom lens system described in Examples 1 to 5, the plurality of movable lens groups may also include at least four movable lens groups that move between the fixed lens group on the smallest reduction side and the fixed lens group on the largest magnification side during zooming from the wide-angle end to the telephoto end.

[0100] As an example, in embodiments 1 to 5, when zooming from the wide-angle end to the telephoto end, the second lens group G2 to the fifth lens group G5 can also move between the sixth lens group G6 and the first lens group G1.

[0101] With this structure, the number of movable lens groups contributing to the focal length variation of the zoom lens system as a whole increases, thereby reducing the amount of movement of each movable lens group. Consequently, less aberration occurs during zooming, and therefore the amount of movement of the compensator lens group, which moves to correct aberration, is also reduced, enabling miniaturization of the zoom lens system. Furthermore, it allows for better correction of aberrations generated during zooming, achieving higher performance.

[0102] Furthermore, in the zoom lens systems described in Embodiments 1 to 5, the magnifying optical system may include a first focusing lens group that can move along the optical axis during focusing, and the relay optical system may include a second focusing lens group that can move along the optical axis during focusing.

[0103] With this structure, the amount of image plane curvature aberration is reduced during focusing, resulting in good image quality. Furthermore, the mechanisms for positioning each focusing lens group are dispersed, thus allowing the lens barrel's center of gravity to shift towards the reduction side.

[0104] Furthermore, the zoom lens systems involved in Examples 1 to 5 can also satisfy the following condition (2).

[0105] 10 < fN / fw < 5000 (2)

[0106] Here,

[0107] fN: The focal length of the minimized side movable lens group;

[0108] fw: The focal length of the entire system at the wide-angle end.

[0109] Condition (2) is a conditional expression used to define the relationship between the focal length of the minimized-side moving lens group and the focal point of the entire system at the wide-angle end. By satisfying condition (2), a lens system with a wide angle and a small lens diameter can be achieved. If the value is below the lower limit of condition (2), the effective diameter of the minimized-side moving lens group becomes larger and heavier. If the value exceeds the upper limit of condition (2), the optical power of the minimized-side moving lens group becomes too weak and cannot properly correct the image plane curvature.

[0110] In addition to condition (2), even more favorable results can be obtained by further satisfying the following condition (2A).

[0111] 100 < fN / fw < 4500 (2A)

[0112] Furthermore, the zoom lens systems involved in Examples 1 to 5 can also satisfy the following condition (3).

[0113] 3.0 < Ymax·f2 / fw 2 <16.0 (3)

[0114] Here,

[0115] f2: The focal length of the magnifying optical system;

[0116] fw: The focal length of the entire system at the wide-angle end.

[0117] Condition (3) is a conditional expression used to define the relationship between the effective image circle diameter on the reduced side, the focal length of the magnifying optical system, and the focal length of the entire system at the wide-angle end. By satisfying condition (3), miniaturization and high performance can be achieved. If the effective image circle diameter is below the lower limit of condition (3), it becomes too small relative to the focal length of the entire system, and the optical power of the magnifying optical system becomes too strong relative to the focal length of the entire system. The balance between correcting spherical aberration and astigmatism together with the magnifying optical system deteriorates, making it difficult to achieve high performance. If the effective image circle diameter is above the upper limit of condition (3), it becomes too large relative to the focal length of the entire system, and the optical power of the magnifying optical system becomes weak relative to the focal length of the entire system. Miniaturization of the optical system as a whole becomes difficult.

[0118] Furthermore, based on condition (3), even more favorable results can be obtained by further satisfying the following condition (3A).

[0119] 4.0 < Ymax·f2 / fw 2 <15.0 (3A)

[0120] Furthermore, the zoom lens systems involved in Examples 1 to 5 can also satisfy the following condition (4).

[0121] 0.02 < enP / TL1 < 0.35 (4)

[0122] Here,

[0123] enP: The distance on the optical axis from the surface closest to the magnification side of the magnifying optical system to the position of the incident pupil when the magnification side is set as the incident side;

[0124] TL1: The distance on the optical axis from the smallest side of the magnifying optical system to the side closest to the magnifying side.

[0125] Condition (4) is a conditional expression defining the ratio of the distance along the optical axis from the surface closest to the magnification side of the magnifying optical system to the position of the incident pupil when the magnification side is set as the incident side, to the total length of the lens of the magnifying optical system. In a conventional optical system that does not form an intermediate image, a long back focal length needs to be ensured. In contrast, in this embodiment, a single intermediate image is formed, and a long back focal length is ensured by a relay optical system. Thus, compared to a conventional optical system, the position of the incident pupil can be made closer to the magnification side, and a wide-angle view can be achieved while reducing the diameter of the lens closest to the magnification side of the magnifying optical system. If the value is below the lower limit of condition (4), the total length of the lens of the magnifying optical system becomes larger, and the diameter of the lens closest to the magnification side becomes larger. If the value exceeds the upper limit of condition (4), the position of the incident pupil becomes closer to the reduction side, and it becomes difficult to ensure the desired angle of view.

[0126] Furthermore, based on condition (4), even more favorable results can be obtained by further satisfying the following condition (4A).

[0127] 0.05 < enP / TL1 < 0.30 (4A)

[0128] Furthermore, the zoom lens systems involved in Examples 1 to 5 can also satisfy the following condition (5).

[0129] 2.0 < fN1 / fw < 25.0 (5)

[0130] Here,

[0131] fN1: The focal length of the negative lens element located on the magnification side among the multiple lens elements constituting the smallest side movable lens group;

[0132] fw: The focal length of the entire system at the wide-angle end.

[0133] Condition (5) is a conditional expression used to define the relationship between the focal length of the negative lens element located on the magnification side among the multiple lens elements constituting the least narrowing side moving lens group and the focal point of the entire system at the wide-angle end. By satisfying condition (5), the refractive power of the negative lens element can be ensured, which is beneficial for the correction of astigmatism and can contribute to reducing the number of lenses constituting the least narrowing side moving lens group. If the value is below the lower limit of condition (5), the refractive power of the negative lens element becomes too strong, and thus becomes overcorrected. As a result, the number of positive lenses arranged on the narrowing side is increased. If the value is above the upper limit of condition (5), the refractive power of the negative lens element cannot be ensured, and the correction of astigmatism becomes insufficient.

[0134] Furthermore, based on condition (5), even more favorable results can be obtained by further satisfying the following condition (5A).

[0135] 3.0 < fN1 / fw < 24.0 (5A)

[0136] Furthermore, the zoom lens systems involved in Examples 1 to 5 can also satisfy the following condition (6).

[0137] -27.0 < fP1 / fw < -4.0 (6)

[0138] Here,

[0139] fP1: The focal length of the positive lens element located on the magnification side among the multiple lens elements constituting the smallest side movable lens group;

[0140] fw: The focal length of the entire system at the wide-angle end.

[0141] Condition (6) is a conditional expression used to define the relationship between the focal length of the positive lens element located on the magnification side among the multiple lens elements constituting the least-reduced moving lens group and the focal point of the entire system at the wide-angle end. By satisfying condition (6), the refractive power of the positive lens element can be ensured, which is beneficial for the correction of astigmatism and can contribute to reducing the number of lenses constituting the least-reduced moving lens group. If the value is below the lower limit of condition (6), the refractive power of the positive lens element becomes too strong, and thus becomes overcorrected. As a result, the number of negative lenses arranged on the less-reduced side than the positive lens element increases. If the value is above the upper limit of condition (6), the refractive power of the positive lens element cannot be ensured, and the correction of astigmatism becomes insufficient.

[0142] Furthermore, based on condition (6), even more favorable results can be obtained by further satisfying the following condition (6A).

[0143] -26.0 < fP1 / fw < -5.0 (6A)

[0144] As described above, several embodiments have been illustrated as examples of the technology disclosed in this application. However, the technology in this disclosure is not limited thereto and can be applied to implementations with appropriate modifications, substitutions, additions, omissions, etc.

[0145] The following describes numerical embodiments of the zoom lens system according to Examples 1 to 5. In each numerical embodiment, the unit of length in the table is "mm", and the unit of angle of view is "°". Furthermore, in each numerical embodiment, r is the radius of curvature, d is the surface spacing, nd is the refractive index relative to the d-line, and vd is the Abbe number relative to the d-line. Additionally, in each numerical embodiment, surfaces marked with * are aspherical surfaces, and the shape of an aspherical surface is defined by the following formula.

[0146] [Mathematical Expression 1]

[0147]

[0148] Here,

[0149] Z: The distance from a point on the aspherical surface at a height h from the optical axis to the tangent plane at the vertex of the aspherical surface;

[0150] h: Height from the optical axis;

[0151] r: Vertex radius of curvature;

[0152] κ: Conic constant;

[0153] An: nth degree aspheric coefficient.

[0154] (Numerical Example 1)

[0155] For the zoom lens system of numerical embodiment 1 (corresponding to embodiment 1), the surface data is shown in Table 1, the various data are shown in Table 2, the focal point data is shown in Table 3, and the single lens data is shown in Table 4 (unit: mm).

[0156] [Table 1]

[0157] Surface data

[0158]

[0159]

[0160]

[0161] Aspherical data

[0162] Page 1

[0163] K=0.00000E+00,A3=3.39820E-05,A4=-1.51102E-07,A5=-4.58997E-08 A6=1.59795E-09, A7=-1.70289E-11, A8=-4.83390E-14, A9=2.30699E-15 A10=-1.29896E-17

[0164] Page 2

[0165] K=-7.96856E-01,A3=7.17508E-05,A4=-4.26012E-06,A5=3.28783E-09 A6=8.82707E-11, A7=-4.41750E-14, A8=3.60550E-14, A9=3.79852E-16 A10=-1.13853E-17

[0166] Page 11

[0167] K=0.00000E+00,A3=0.00000E+00,A4=-2.02960E-05,A5=0.00000E+00 A6=-3.69442E-08, A7=0.00000E+00, A8=-1.54744E-10, A9=0.00000E+00 A10=-9.62371E-13

[0168] Page 12

[0169] K=0.00000E+00,A3=0.00000E+00,A4=4.14867E-06,A5=0.00000E+00 A6=6.06723E-09, A7=0.00000E+00, A8=-2.46057E-12, A9=0.00000E+00 A10=0.00000E+00

[0170] [Table 2]

[0171] Various data

[0172]

[0173]

[0174] [Table 3]

[0175] Focus Data

[0176] [Table 4]

[0177] Single lens data

[0178]

[0179] (Numerical Example 2)

[0180] For the zoom lens system of numerical embodiment 2 (corresponding to embodiment 2), the surface data is shown in Table 5, various data are shown in Table 6, the focal point data is shown in Table 7, and the single lens data is shown in Table 8 (unit: mm).

[0181] [Table 5]

[0182] Surface data

[0183]

[0184]

[0185]

[0186] Aspherical data

[0187] Page 1

[0188] K=0.00000E+00,A3=3.47339E-05,A4=-6.74283E-07,A5=-3.45951E-08 A6=1.51025E-09, A7=-1.70058E-11, A8=-4.88886E-14, A9=2.32790E-15 A10=-1.29625E-17

[0189] Page 2

[0190] K=-8.14220E-01,A3=7.29749E-05,A4=-4.65798E-06,A5=9.07093E-09 A6=1.38885E-10, A7=6.41794E-13, A8=4.24196E-15, A9=3.10765E-16 A10=-7.64882E-18

[0191] Page 11

[0192] K=0.00000E+00,A3=0.00000E+00,A4=-1.89513E-05,A5=0.00000E+00 A6=-3.99376E-08, A7=0.00000E+00, A8=-9.35343E-11, A9=0.00000E+00 A10=-1.63883E-12

[0193] Page 12

[0194] K=0.00000E+00,A3=0.00000E+00,A4=3.93978E-06,A5=0.00000E+00 A6=4.49592E-09,A7=0.00000E+00,A8=1.93270E-11,A9=0.00000E+00 A10=0.00000E+00

[0195] [Table 6]

[0196] Various data

[0197]

[0198] [Table 7]

[0199] Focus Data

[0200]

[0201] [Table 8]

[0202] Single lens data

[0203]

[0204]

[0205] (Numerical Example 3)

[0206] For the zoom lens system of numerical embodiment 3 (corresponding to embodiment 3), the surface data is shown in Table 9, the various data are shown in Table 10, the focal point data is shown in Table 11, and the single lens data is shown in Table 12 (unit: mm).

[0207] [Table 9]

[0208] Surface data

[0209]

[0210]

[0211] Aspherical data

[0212] Page 1

[0213] K=0.00000E+00,A3=3.56263E-05,A4=-6.70122E-07,A5=-3.52652E-08 A6=1.52095E-09, A7=-1.70058E-11, A8=-4.88886E-14, A9=2.31926E-15 A10=-1.29625E-17

[0214] Page 2

[0215] K=-8.13160E-01,A3=7.26090E-05,A4=-4.66900E-06,A5=9.07850E-09 A6=1.40082E-10, A7=6.57697E-13, A8=4.33351E-15, A9=3.07920E-16 A10=-7.76577E-18

[0216] Page 11

[0217] K=0.00000E+00,A3=0.00000E+00,A4=-1.74363E-05,A5=0.00000E+00 A6=-3.14611E-08, A7=0.00000E+00, A8=-1.57381E-10, A9=0.00000E+00 A10=-9.46957E-13

[0218] Page 12

[0219] K=0.00000E+00,A3=0.00000E+00,A4=3.32932E-06,A5=0.00000E+00 A6=4.08635E-09,A7=0.00000E+00,A8=5.86116E-12,A9=0.00000E+00 A10=0.00000E+00

[0220] [Table 10]

[0221] Various data

[0222]

[0223] [Table 11]

[0224] Focus Data

[0225]

[0226]

[0227] [Table 12]

[0228] Single lens data

[0229]

[0230] (Numerical Example 4)

[0231] For the zoom lens system of numerical embodiment 4 (corresponding to embodiment 4), the surface data is shown in Table 13, various data are shown in Table 14, the focal point data is shown in Table 15, and the single lens data is shown in Table 16 (unit: mm).

[0232] [Table 13]

[0233] Surface data

[0234]

[0235]

[0236] Aspherical data

[0237] Page 1

[0238] K=0.00000E+00,A3=3.51052E-05,A4=-6.50035E-07,A5=-3.56593E-08 A6=1.52395E-09, A7=-1.70058E-11, A8=-4.88886E-14, A9=2.31822E-15 A10=-1.29625E-17

[0239] Page 2

[0240] K=-8.13070E-01,A3=7.28199E-05,A4=-4.67421E-06,A5=9.05250E-09 A6=1.40447E-10, A7=6.64689E-13, A8=4.39462E-15, A9=3.07470E-16 A10=-7.80113E-18

[0241] Page 11

[0242] K=0.00000E+00,A3=0.00000E+00,A4=-1.78833E-05,A5=0.00000E+00 A6=-3.25591E-08, A7=0.00000E+00, A8=-1.60452E-10, A9=0.00000E+00 A10=-1.00596E-12

[0243] Page 12

[0244] K=0.00000E+00,A3=0.00000E+00,A4=3.42081E-06,A5=0.00000E+00 A6=4.30100E-09,A7=0.00000E+00,A8=5.56065E-12,A9=0.00000E+00 A10=0.00000E+00

[0245] [Table 14]

[0246] Various data

[0247]

[0248] [Table 15]

[0249] Focus Data

[0250]

[0251] [Table 16]

[0252] Single lens data

[0253]

[0254]

[0255] (Numerical Example 5)

[0256] For the zoom lens system of numerical embodiment 5 (corresponding to embodiment 5), the surface data is shown in Table 17, various data are shown in Table 18, the focal point data is shown in Table 19, and the single lens data is shown in Table 20 (unit: mm).

[0257] [Table 17]

[0258] Surface data

[0259]

[0260]

[0261]

[0262] Aspherical data

[0263] Page 1

[0264] K=0.00000E+00,A3=3.50560E-05,A4=-6.26647E-07,A5=-3.64379E-08 A6=1.53157E-09, A7=-1.70058E-11, A8=-4.88886E-14, A9=2.31486E-15 A10=-1.29625E-17

[0265] Page 2

[0266] K=-8.13220E-01,A3=7.38627E-05,A4=-4.69123E-06,A5=8.97173E-09 A6=1.40980E-10, A7=6.82314E-13, A8=4.57316E-15, A9=3.06921E-16 A10=-7.86124E-18

[0267] Page 11

[0268] K=0.00000E+00,A3=0.00000E+00,A4=-1.86266E-05,A5=0.00000E+00 A6=-3.61032E-08, A7=0.00000E+00, A8=-1.69497E-10, A9=0.00000E+00 A10=-1.12305E-12

[0269] Page 12

[0270] K=0.00000E+00,A3=0.00000E+00,A4=3.39082E-06,A5=0.00000E+00 A6=4.78562E-09,A7=0.00000E+00,A8=2.25262E-13,A9=0.00000E+00 A10=0.00000E+00

[0271] [Table 18]

[0272] Various data

[0273]

[0274]

[0275] [Table 19]

[0276] Focus Data

[0277]

[0278] [Table 20]

[0279] Single lens data

[0280]

[0281]

[0282] The corresponding values ​​of each conditional expression in each numerical embodiment are shown in Table 21 below.

[0283] [Table 21]

[0284] (1) 0.076 0.076 0.074 0.068 0.059 (2) 2864.3 3111.3 748.4 675.8 405.1 (3) 7.981 7.571 7.590 7.592 7.625 (4) 0.177 0.181 0.181 0.181 0.182 (5) 12.508 14.508 14.139 14.032 13.654 (6) -14.704 -17.361 -17.170 -17.075 -16.871

[0285] The values ​​of the variables in each conditional expression (1) to (6) in each numerical embodiment are shown in Table 22 below.

[0286] [Table 22]

[0287] CTN 2.62749 2.63827 2.55 2.35 2.05 Ymax 34.53000 34.53000 34.53000 34.53000 34.53000 fN -20679.55188 -22478.40021 -5406.23086 -4881.53719 -2926.02913 fw -7.21979 -7.22480 -7.22360 -7.22330 -7.22310 f2 12.0 11.4 11.5 11.5 11.5 enP 41.6882 42.4243 42.1904 42.19 42.14 TL1 236.021 234.387 233.46 233.44 232.07 fN1 -90.3026 -104.8150 -102.1322 -101.3582 -98.6254 fP1 106.16 125.43 124.03 123.34 121.86

[0288] CTN: The amount of movement of the smallest moving lens group among multiple moving lens groups during zooming.

[0289] Ymax: Effective image circle diameter on the narrowed side

[0290] fN: Focal length of the minimizing side moving lens group

[0291] fw: Focal length of the entire system at the wide-angle end

[0292] f2: Focal length of the magnifying optical system

[0293] enP: The distance on the optical axis from the surface closest to the magnification side of the magnifying optical system to the position of the incident pupil when the magnification side is set as the incident side.

[0294] TL1: The distance along the optical axis from the smallest side of the magnifying optical system to the surface closest to the magnifying side.

[0295] fN1: The focal length of the negative lens element located on the magnifying side among the multiple lens elements constituting the minimizing side moving lens group.

[0296] fP1: The focal length of the positive lens element located on the magnifying side among the multiple lens elements constituting the minimizing side moving lens group.

[0297] (Implementation Method 2)

[0298] The following uses Figure 26 Embodiment 2 of this disclosure will be described. Figure 26 This is a block diagram illustrating an example of an image projection apparatus according to this disclosure. The image projection apparatus 100 includes an optical system 1, an image forming element 101, a light source 102, and a control unit 110, as disclosed in Embodiment 1. The image forming element 101 is composed of a liquid crystal, a DMD, or the like, and generates an image projected onto the screen SR via the optical system 1. The light source 102 is composed of an LED (light-emitting diode), a laser, or the like, and supplies light to the image forming element 101. The control unit 110 is composed of a CPU or an MPU, and controls the entire apparatus and its components. The optical system 1 can also be configured as a replaceable lens that can be freely mounted and detached from the image projection apparatus 100. In this case, the apparatus after removing the optical system 1 from the image projection apparatus 100 is an example of the main apparatus.

[0299] The image projection device 100 described above can achieve wide-angle zoom function through the optical system 1 according to Embodiment 1, and can achieve miniaturization and weight reduction of the device.

[0300] (Implementation Method 3)

[0301] The following uses Figure 27 Embodiment 3 of this disclosure will be described. Figure 27This is a block diagram illustrating an example of the imaging device disclosed herein. The imaging device 200 includes the optical system 1, imaging element 201, and control unit 210 disclosed in Embodiment 1. The imaging element 201 is composed of a CCD (charge-coupled device) image sensor, a CMOS image sensor, etc., and receives the optical image of the object OBJ formed by the optical system 1 and converts it into an electrical image signal. The control unit 110 is composed of a CPU or MPU, etc., and controls the entire device and its components. The optical system 1 may also be configured as a replaceable lens that can be freely mounted and detached from the imaging device 200. In this case, the device after removing the optical system 1 from the imaging device 200 is an example of the main device.

[0302] The above-described camera device 200 can achieve wide-angle zoom function through the optical system 1 according to Embodiment 1, and can achieve miniaturization and weight reduction of the device.

[0303] As described above, embodiments have been explained as a disclosure of the technology in this disclosure. For this purpose, accompanying drawings and detailed descriptions are provided.

[0304] Therefore, the constituent elements described in the accompanying drawings and detailed descriptions include not only those essential for solving the problem, but also those not essential for illustrating the above-mentioned technology. Thus, the mere presence of these non-essential elements in the drawings or detailed descriptions should not automatically render them essential.

[0305] Furthermore, the above-described embodiments are used to illustrate the technology in this disclosure, so various changes, substitutions, additions, omissions, etc., can be made within the scope of the patent claim or its equivalents.

[0306] Industrial availability

[0307] This disclosure can be applied to image projection devices such as projectors and head-up displays, as well as imaging devices such as digital still cameras, digital video cameras, surveillance cameras in monitoring systems, web cameras, and vehicle-mounted cameras. In particular, this disclosure can be applied to optical systems that require high image quality, such as projectors, digital still camera systems, and digital video camera systems.

Claims

1. An optical system having an intermediate imaging position internally conjugate to both a magnification conjugate point on the magnification side and a reduction conjugate point on the reduction side. The optical system includes: A magnifying optical system having multiple lens elements located further from the magnifying side than the intermediate imaging position; and The relay optical system has multiple lens elements located further away from the reduced-size side than the intermediate imaging position. The magnifying optical system is fixed relative to the shrinking conjugate point during zooming. The relay optical system includes multiple movable lens groups that can move independently along the optical axis during zooming. Among the plurality of movable lens groups, the movable lens group located closest to the narrowing side has negative refractive power. The optical system satisfies the following condition (3): Here, Ymax: Effective image circle diameter on the narrowed side; f2: The focal length of the magnifying optical system; fw: The focal length of the entire system at the wide-angle end.

2. The optical system according to claim 1, wherein, The minimized-side moving lens group moves towards the minimized side when zooming from the wide-angle end to the telephoto end.

3. The optical system according to claim 1, wherein, The optical system satisfies the following condition (1): Here, CTN: The amount of movement of the lens group on the smallest side during zooming.

4. The optical system according to claim 1, wherein, The relay optical system includes a minimum reduction side fixed lens group that is fixed relative to the reduction conjugate point and located at the position closest to the reduction side during zooming, the minimum reduction side fixed lens group having positive refractive power.

5. The optical system according to claim 1, wherein, The relay optical system includes a fixed lens group on the magnification side that is fixed relative to the reduction conjugate point and located on the magnification side during zooming.

6. The optical system according to claim 5, wherein, The relay optical system includes a fixed lens group on the narrowest side, which is fixed relative to the narrowing conjugate point and located on the narrowest side during zooming. The plurality of movable lens groups includes at least four movable lens groups that move between the fixed lens group on the smallest reduction side and the fixed lens group on the largest magnification side during zooming from the wide-angle end to the telephoto end.

7. The optical system according to claim 1, wherein, The magnifying optical system includes a first focusing lens group that can move along the optical axis during focusing. The relay optical system includes a second focusing lens group that can move along the optical axis during focusing.

8. The optical system according to claim 1, wherein, The optical system satisfies the following condition (2): Here, fN: The focal length of the minimized side movable lens group; fw: The focal length of the entire system at the wide-angle end.

9. The optical system according to claim 1, wherein, The optical system satisfies the following condition (4): Here, enP: The distance on the optical axis from the surface closest to the magnification side of the magnifying optical system to the position of the incident pupil when the magnification side is set as the incident side; TL1: The distance along the optical axis from the surface closest to the shrinking side to the surface closest to the magnifying side of the magnifying optical system.

10. The optical system according to claim 1, wherein, The optical system satisfies the following condition (5): Here, fN1: The focal length of the negative lens element located on the magnification side among the multiple lens elements constituting the smallest side movable lens group; fw: The focal length of the entire system at the wide-angle end.

11. The optical system according to claim 1, wherein, The optical system satisfies the following condition (6): Here, fP1: The focal length of the positive lens element located on the magnification side among the multiple lens elements constituting the smallest side movable lens group; fw: The focal length of the entire system at the wide-angle end.

12. An image projection device, comprising: The optical system according to any one of claims 1 to 11; and An image forming element generates an image that is projected onto a screen via the optical system.

13. A camera device, comprising: The optical system according to any one of claims 1 to 11; and The camera element receives the optical image formed by the optical system and converts it into an electrical image signal.

Images