Zoom lens, projection-type display device, and image pickup device

Abstract

Provided is a zoom lens in which variation in F number at the time of zooming is suppressed, which is wide-angle, has high magnification and high performance, and forms an intermediate image, a projection-type display device provided with the zoom lens, and an imaging device provided with the zoom lens. The zoom lens includes, in order from the magnification side, a first optical system including a lens at the most magnification side, and a second optical system forming an intermediate image. The first optical system causes the intermediate image to be reimaged on a magnification side image surface. The second optical system is provided with a lens group including an aperture stop and having negative refractive power and moving at the time of zooming. The zoom lens satisfies a conditional expression related to a focal length fAp of the lens group including the aperture stop and a focal length f2w of the second optical system at the wide-angle end: 0.1 < f2w / fAp < 2.1.

Description

Technical Field

[0001] The present invention relates to a zoom lens, a projection display device, and a camera device. Background Technology

[0002] As a zoom lens applicable to projection display devices or camera devices, for example, the lens system described in Patent Document 1, Patent Document 2 and Patent Document 3 are known.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2017-102239

[0004] Patent Document 2: Japanese Patent Application Publication No. 2015-179270

[0005] Patent Document 3: Japanese Patent Application Publication No. 2019-095789

[0006] In recent years, there has been a demand for a zoom lens that, while suppressing the change in F-number during zooming, can also be wide-angle, high-magnification, and high-performance, in a zoom lens that forms an intermediate image. Summary of the Invention

[0007] The present invention was made in view of the above circumstances, and its object is to provide a zoom lens that, in a zoom lens that forms an intermediate image, suppresses the change of F-value during zooming while being wide-angle, high-magnification, and high-performance; a projection display device having the zoom lens; and a camera device having the zoom lens.

[0008] The zoom lens according to one aspect of the present invention includes a first optical system and a second optical system sequentially along the optical path from the magnification side to the reduction side. The second optical system forms an intermediate image at a position conjugate with the image plane on the reduction side. The first optical system re-images the intermediate image onto the image plane on the magnification side. The zoom lens includes a lens on the magnification side of the optical path of the first optical system. When the group whose optical axis spacing changes during zooming is set as a lens group, the second optical system includes a plurality of lens groups that move during zooming. One of the plurality of lens groups that moves during zooming is a lens group with an aperture diaphragm that determines the numerical aperture. The lens group with the aperture diaphragm has negative refractive power. When the focal length of the lens group with the aperture diaphragm is set to fAp and the focal length of the second optical system at the wide-angle end is set to f2w, the zoom lens satisfies the following conditional expression (1).

[0009] 0.1 < f2w / fAp < 2.1 (1)

[0010] The zoom lens described above preferably satisfies the following condition (1-1).

[0011] 0.2 < f2w / fAp < 1.8 (1-1)

[0012] When the difference in the optical axis direction between the position of the lens group with aperture at the wide-angle end and the position of the lens group with aperture at the telephoto end is set as ZAp, and the focal length of the zoom lens at the wide-angle end is set as fw, the zoom lens of the above method preferably satisfies the following condition (2), and more preferably satisfies the following condition (2-1).

[0013] 4<ZAp / |fw|<10 (2)

[0014] 4.7 < ZAp / |fw| < 8 (2-1)

[0015] When the average of the dispersion coefficients of the d-line reference of all positive lenses included in the lens group with aperture is set to νAp, the zoom lens of the above manner preferably satisfies the following condition (3), and more preferably satisfies the following condition (3-1).

[0016] 65<νAp (3)

[0017] 70 < νAp < 90 (3-1)

[0018] Preferably, during zooming, the aperture opening diameter is variable, and the numerical aperture of the zoom lens is constant throughout the zoom range.

[0019] When the focal length of the zoom lens at the wide-angle end is set to fw and the focal length of the second optical system at the wide-angle end is set to f2w, the zoom lens of the above-described manner preferably satisfies the following condition (4), and more preferably satisfies the following condition (4-1).

[0020] -0.1 < |fw| / f2w < 0 (4)

[0021] -0.06<|fw| / f2w<0 (4-1)

[0022] When the focal length of the lens group with aperture is set to fAp, and the focal length of the lens group that moves during zooming and is arranged adjacent to the lens group with aperture on the narrowing side is set to fR, the zoom lens of the above manner preferably satisfies the following condition (5), and more preferably satisfies the following condition (5-1).

[0023] -1.2 < fR / fAp < -0.1 (5)

[0024] -1 < fR / fAp < -0.2 (5-1)

[0025] When the back focal length of the zoom lens at the wide-angle end is set to Bfw on the reduced side of the air conversion distance meter, and the focal length of the zoom lens at the wide-angle end is set to fw, the zoom lens in the above manner preferably satisfies the following condition (6), and more preferably satisfies the following condition (6-1).

[0026] 4<Bfw / |fw| (6)

[0027] 5 < Bfw / |fw| < 10 (6-1)

[0028] The zoom lens described above preferably includes six lens groups. The lens group on the magnification side of the zoom lens has positive refractive power and is fixed relative to the reduction side image plane when zooming. The lens group on the reduction side of the zoom lens has positive refractive power and is fixed relative to the reduction side image plane when zooming.

[0029] Preferably, the second optical system includes, sequentially from the reduced side to the magnified side along the optical path, a second A lens group with positive refractive power, a second B lens group with positive refractive power, a second C lens group with negative refractive power, a second D lens group with positive refractive power, and a second E lens group with refractive power. During zooming, the second B lens group, the second C lens group, the second D lens group, and the second E lens group change the spacing in the optical axis direction between them and the adjacent groups and move along the optical axis, while the second A lens group is fixed relative to the image plane on the reduced side.

[0030] Preferably, the first optical system includes multiple focusing groups on the narrower side of the optical path than the maximum air gap of the first optical system at the wide-angle end. The multiple focusing groups move by changing the spacing in the optical axis direction of each other, thereby performing focusing.

[0031] Another aspect of the present invention relates to a projection display device comprising: a light valve for outputting an optical image; and a zoom lens thereof, wherein the zoom lens thereof projects the optical image output from the light valve onto a screen.

[0032] Another aspect of the present invention relates to a camera device that includes a zoom lens as described above.

[0033] Furthermore, the terms "including" and "including" in this specification indicate that, in addition to the constituent elements listed, it may also include: lenses that do not substantially have refractive power; optical elements other than lenses, such as apertures, masks, filters, cover glasses, plane mirrors, and prisms; and mechanism parts such as lens flanges, lens barrels, imaging elements, and shaky correction mechanisms. Moreover, "lens group" may include not only lenses but also optical elements other than lenses, such as apertures, masks, filters, cover glasses, plane mirrors, and prisms.

[0034] In this specification, "group ~ with positive refractive power" and "group ~ with positive refractive power" mean that the group as a whole has positive refractive power. Similarly, "group ~ with negative refractive power" and "group ~ with negative refractive power" mean that the group as a whole has negative refractive power. Unless otherwise specified, the sign of refractive power, radius of curvature, and surface shape associated with lenses including aspherical lenses are in paraxial region.

[0035] The values ​​used in the conditional expressions are based on the d-line. The "d-line", "C-line" and "F-line" described in this specification are bright lines, with the wavelength of the d-line considered to be 587.56 nm, the wavelength of the C-line considered to be 656.27 nm, and the wavelength of the F-line considered to be 486.13 nm.

[0036] Invention Effects

[0037] According to the technology of the present invention, it is possible to provide a zoom lens that, in a zoom lens that forms an intermediate image, suppresses the change of F-value during zooming while being wide-angle, high-magnification, and high-performance, as well as a projection display device having the zoom lens and a camera device having the zoom lens. Attached Figure Description

[0038] Figure 1 Corresponding to the zoom lens of Embodiment 1, this is a cross-sectional view of the structure and beam of a zoom lens, illustrating an example of an embodiment of the present invention.

[0039] Figure 2 These are aberration diagrams of the zoom lens in Example 1.

[0040] Figure 3 This is a cross-sectional view showing the structure and beam of the zoom lens in Embodiment 2.

[0041] Figure 4 These are aberration diagrams of the zoom lens in Example 2.

[0042] Figure 5 This is a cross-sectional view showing the structure and beam of the zoom lens in Embodiment 3.

[0043] Figure 6 These are aberration diagrams of the zoom lens in Example 3.

[0044] Figure 7 This is a schematic structural diagram of a projection-type display device according to one embodiment.

[0045] Figure 8 This is a schematic structural diagram of a projection-type display device according to another embodiment.

[0046] Figure 9 This is a schematic structural diagram of a projection-type display device according to another embodiment.

[0047] Figure 10 This is a perspective view of the front side of a camera device according to one embodiment.

[0048] Figure 11 yes Figure 10 A perspective view of the rear side of the camera device shown. Detailed Implementation

[0049] Hereinafter, an example of an embodiment of the technology of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 The diagram shows the structure of a zoom lens at the wide-angle end, including the optical axis Z, according to an embodiment of the present invention. Figure 1 The structural example shown corresponds to Embodiment 1 described later. Figure 1 The image also shows the on-axis beam Ka and the beam Kb with the maximum viewing angle.

[0050] The zoom lens of this embodiment can be used as a projection optical system mounted on a projection display device, and also as a camera optical system mounted on a camera device. Hereinafter, we will describe its use as a projection optical system.

[0051] exist Figure 1 In this example, assuming a zoom lens is mounted on a projection display device, an optical component PP is shown, positioned on the reduced-size side of the zoom lens. The optical component PP is envisioned as a filter, cover glass, or color-combining prism, etc. The optical component PP may be a component without refractive power, or it may be omitted entirely.

[0052] and, Figure 1 In this example, assuming a zoom lens is mounted on a projection display device, an image display surface (Sim) of a light valve is also shown. In the projection display device, a light beam imbued with image information on the image display surface (Sim) is incident on the zoom lens via an optical component (PP) and projected onto a screen (not shown) through the zoom lens. In this case, the image display surface (Sim) corresponds to the reduction-side imaging surface, and the screen corresponds to the magnification-side imaging surface.

[0053] Additionally, in this specification, "magnification side" refers to the screen side of the optical path, and "reduction side" refers to the image display surface (SIM) side of the optical path. In the following description, to avoid lengthy explanations, "in sequence along the optical path from magnification side to reduction side" is sometimes written as "in sequence from magnification side to reduction side." Similarly, "in sequence along the optical path from reduction side to magnification side" is sometimes written as "in sequence from reduction side to magnification side."

[0054] like Figure 1As shown, the zoom lens of this embodiment includes a first optical system G1 and a second optical system G2 sequentially along the optical path from the magnification side to the reduction side. The second optical system G2 forms an intermediate image MI at a position conjugate with the image plane on the reduction side. The first optical system G1 re-images the intermediate image MI onto the image plane on the magnification side. Figure 1 In the example, the intermediate image MI is formed on the optical path between the first optical system G1 and the second optical system G2. Figure 1 The intermediate image MI is shown only with dotted lines to indicate its position on the optical axis Z, without showing its exact shape.

[0055] In a projection-type display device, a second optical system G2 forms an intermediate image MI of an image displayed on an image display surface Sim, and a first optical system G1 projects this intermediate image MI onto a screen to form a projected image. Thus, in an optical system that forms the intermediate image MI, the back focal length of the first optical system G1 can be shortened, and the diameter of the lens on the magnifying side of the first optical system G1 can be reduced, thereby shortening the focal length of the entire system to create a structure suitable for wide-angle viewing.

[0056] As an example, Figure 1 The first optical system G1, from the shrinking side to the magnifying side, includes a mirror R1, lenses L1a to L1f, a mirror R2, and lenses L1g to L1l. Mirrors R1 and R2 are optical path bending components that bend the optical path by 90 degrees.

[0057] like Figure 1 As shown, the zoom lens in this embodiment includes a lens on the side closest to the magnification in the optical path of the first optical system G1. Unlike this embodiment, in projection optical systems where a reflective component such as a mirror is included on the side closest to the magnification, the light beam near the optical axis Z cannot reach the screen and therefore cannot be used for imaging. However, this defect can be avoided in this embodiment.

[0058] As an example, Figure 1 The second optical system G2, from the reduction side to the magnification side, includes lenses L2a to L2h, an aperture St, and lenses L2i to L2n. Lens L2a constitutes lens group G2A (2A). Lenses L2b to L2d constitute lens group G2B (2B). Lenses L2e to L2h and aperture St constitute lens group G2C (2C). Lens L2i constitutes lens group G2D (2D). Lenses L2j to L2m constitute lens group G2E (2E). Furthermore, in the technology of this invention, a lens group is defined as a group whose spacing in the Z-direction of the optical axis changes during zooming. The lens group is not limited to a structure including multiple lenses; it can also be a structure including only one lens.

[0059] like Figure 1As shown, the second optical system G2 includes multiple lens groups that move during zooming. According to this structure, zooming can be performed solely through the second optical system G2, thus allowing zooming to be adjusted based on changes in the relay magnification of the second optical system G2, i.e., changes in the size of the intermediate image MI. This simplifies the structure of the optical system. Furthermore, by using lenses that move during zooming as lenses in the second optical system G2, which are easier to miniaturize than the first optical system G1, the burden on the drive system can be reduced, and the device can be miniaturized.

[0060] As an example, in Figure 1 In the example, in the lens group of the second optical system G2, the second lens group G2B, the second lens group G2C, the second lens group G2D, and the second lens group G2E move by changing the distance in the Z direction of the optical axis between them and the adjacent groups when zooming.

[0061] In the second optical system G2, one of the multiple lens groups that move during zoom is configured as a lens group with an aperture diaphragm St that determines the numerical aperture. By making the lens group that determines the numerical aperture of the lens system the one that moves during zoom, the entire system can be easily miniaturized. Hereinafter, for ease of explanation, the lens group with aperture diaphragm St in the second optical system G2 will be referred to as the Ap lens group. Figure 1 In the example, lens group 2C G2C corresponds to lens group Ap.

[0062] The Ap lens group is configured as a lens group with negative refractive power. Generally, if the zoom magnification is large, the amount of movement of each lens group increases, and therefore the balance of various aberrations such as spherical aberration and image plane curvature at the wide-angle and telephoto ends is easily degraded significantly. On the other hand, the Ap lens group, which includes a lens optically positioned near the aperture St, is a lens group that has a greater effect on correcting image plane curvature on the wide-angle side, especially the sagittal image plane curvature. While maintaining the balance of image plane curvature including the telephoto side, by imparting negative refractive power to the Ap lens group, the effect of a lens group with a greater corrective effect including the telephoto side can be achieved, thereby further reducing the deterioration of the aberration balance between the wide-angle and telephoto ends. Based on the above, by imparting negative refractive power to the Ap lens group, it is easy to suppress aberration changes associated with high magnification. When the Ap lens group has negative refractive power and the zoom lens satisfies the following condition (1), it is easy to suppress the change of F-value during zoom while taking into account both high magnification and aberration correction.

[0063] When the focal length of the Ap lens group is set to fAp and the focal length of the second optical system G2 at the wide-angle end is set to f2w, the zoom lens preferably satisfies the following condition (1). Generally, if the lens group with aperture St moves during zooming, the F-value tends to change with zoom. Condition (1) is a condition for achieving high magnification while suppressing the change in F-value with zoom. By ensuring that the corresponding value of condition (1) is not below the lower limit, the refractive power of the Ap lens group in the second optical system G2 will not become too weak, thus suppressing the amount of movement of the Ap lens group during zooming. As a result, the increase in the total length of the lens can be suppressed, and the change in F-value when zooming from the wide-angle end to the telephoto end can be suppressed. By ensuring that the corresponding value of condition (1) is not above the upper limit, the refractive power of the Ap lens group in the second optical system G2 will not become too strong, thus suppressing the changes in various aberrations such as spherical aberration and on-axis chromatic aberration with zoom, thus facilitating high magnification. To obtain better characteristics, zoom lenses are more preferably satisfied with the following condition (1-1).

[0064] 0.1 < f2w / fAp < 2.1 (1)

[0065] 0.2 < f2w / fAp < 1.8 (1-1)

[0066] When the difference in the optical axis along the Z direction between the position of the Ap lens group at the wide-angle end and the position of the Ap lens group at the telephoto end is set to ZAp, and the focal length of the zoom lens at the wide-angle end is set to fw, the zoom lens preferably satisfies the following condition (2). By ensuring that the corresponding value of condition (2) is not below the lower limit, it is easy to achieve high magnification. By ensuring that the corresponding value of condition (2) is not above the upper limit, the amount of movement of the Ap lens group during zooming can be suppressed, and thus the variation of the F-value during zooming can be suppressed. To obtain better characteristics, the zoom lens more preferably satisfies the following condition (2-1).

[0067] 4<ZAp / |fw|<10 (2)

[0068] 4.7 < ZAp / |fw| < 8 (2-1)

[0069] When the average dispersion coefficient of the d-line reference of all positive lenses included in the Ap lens group is set to νAp, the zoom lens preferably satisfies the following condition (3). By ensuring that the corresponding value of condition (3) is not below the lower limit, on-axis chromatic aberration can be easily corrected. To obtain better characteristics, the zoom lens more preferably satisfies the following condition (3-1). By ensuring that the corresponding value of condition (3-1) is not above the upper limit, the price of lens materials can be suppressed, thus facilitating cost reduction.

[0070] 65<νAp (3)

[0071] 70 < νAp < 90 (3-1)

[0072] Preferably, during zooming, the aperture diameter of the aperture St included in the Ap lens group is variable, and the numerical aperture of the zoom lens remains constant throughout the zoom range. That is, preferably, the aperture St is a variable aperture whose aperture diameter can change during zooming, so that the numerical aperture of the zoom lens remains constant throughout the zoom range. By setting it to this variable aperture, the increase in F-number when zooming from the wide-angle end to the telephoto end can be prevented, thus suppressing the decrease in brightness at the telephoto end.

[0073] When the focal length of the zoom lens at the wide-angle end is set to fw, and the focal length of the second optical system G2 at the wide-angle end is set to f2w, the zoom lens preferably satisfies the following condition (4). By ensuring that the corresponding value of condition (4) is not below the lower limit, the negative refractive power of the second optical system G2 will not become too strong, and therefore the positive refractive power of the first optical system G1 will not become too strong. Thus, it is possible to suppress the increase in the angle of the off-axis principal ray from the first optical system G1 toward the second optical system G2 relative to the optical axis Z. As a result, it is possible to suppress the large-diameter increase of the lens on the magnification side in the second optical system G2, and it is beneficial to correct the image plane curvature. By ensuring that the corresponding value of condition (4) is not above the upper limit, it is possible to ensure the negative refractive power of the second optical system G2, and thus it is possible to suppress the large-diameter increase of the lens on the reduction side in the first optical system G1. In order to obtain better characteristics, the zoom lens preferably satisfies the following condition (4-1).

[0074] -0.1 < |fw| / f2w < 0 (4)

[0075] -0.06<|fw| / f2w<0 (4-1)

[0076] In the case where a zoom-moving lens group is arranged adjacent to the Ap lens group on the optical path on the reduction side of the Ap lens group, the zoom lens preferably satisfies the following condition (5). Hereinafter, for ease of explanation, the zoom-moving lens group arranged adjacent to the Ap lens group on the optical path on the reduction side of the Ap lens group will be referred to as the R lens group. Figure 1In the example, lens group 2B G2B corresponds to lens group R. In conditional equation (5), the focal length of lens group Ap is set to fAp, and the focal length of lens group R is set to fR. By ensuring that the corresponding value of conditional equation (5) is not below the lower limit, the absolute value of the relative refractive power of lens group R relative to lens group Ap will not become too small, thus suppressing the enlargement of the total lens length. By ensuring that the corresponding value of conditional equation (5) is not above the upper limit, the absolute value of the relative refractive power of lens group R relative to lens group Ap will not become too large, thus facilitating the correction of various aberrations during zoom, especially astigmatism. To obtain better characteristics, zoom lenses more preferably satisfy the following conditional equation (5-1).

[0077] -1.2 < fR / fAp < -0.1 (5)

[0078] -1 < fR / fAp < -0.2 (5-1)

[0079] When the back focal length of the zoom lens at the wide-angle end is set to Bfw on the narrowing side of the air-to-distance meter, and the focal length of the zoom lens at the wide-angle end is set to fw, the zoom lens preferably satisfies the following condition (6). Bfw is the air-to-distance on the optical axis Z from the lens surface closest to the narrowing side to the image surface on the narrowing side of the zoom lens at the wide-angle end. By ensuring that the corresponding value of condition (6) is not below the lower limit, an appropriate back focal length can be ensured, thus facilitating the configuration of color-combining prisms, etc. By ensuring that the corresponding value of condition (6) is not above the upper limit, the enlargement of the entire system, including the back focal length, can be suppressed. To obtain better characteristics, the zoom lens more preferably satisfies the following condition (6-1).

[0080] 4<Bfw / |fw| (6)

[0081] 5 < Bfw / |fw| < 10 (6-1)

[0082] Preferably, the first optical system G1 includes multiple focusing groups on the narrower side of the optical path, which is closer to the reduced side than the maximum air gap of the first optical system G1 at the wide-angle end. These multiple focusing groups move by changing their spacing in the Z-direction of their optical axes, thereby achieving focusing. By moving multiple focusing groups during focusing, aberration variations during focusing are easily suppressed. As an example, Figure 1 The zoom lens includes two focusing groups. Figure 1 In the example, the first focusing group includes lenses L1d and L1e, and the second focusing group includes lens L1f. Figure 1 In the image, double arrows are shown to the left of each focus group.

[0083] like Figure 1As shown, preferably, the second optical system G2 sequentially comprises, from the narrowing side to the magnifying side, a second lens group G2A with positive refractive power, a second lens group G2B with positive refractive power, a second lens group G2C with negative refractive power, a second lens group G2D with positive refractive power, and a second lens group G2E with refractive power along the optical path. Furthermore, preferably, during zooming, the second lens group G2B, the second lens group G2C, the second lens group G2D, and the second lens group G2E move along the optical axis Z by changing the spacing between them and adjacent groups in the Z-direction, while the second lens group G2A remains fixed relative to the narrowing side image plane. The second lens group G2E can be a lens group with positive refractive power or a lens group with negative refractive power.

[0084] By arranging the second optical system G2 as described above, each group can achieve the following effects: Lens group 2A (G2A) easily reduces aberration variations during zoom while maintaining telecentrism on the reduced side. Lens groups 2B (G2B), 2C (G2C), and 2D (G2D) can handle the main zoom function. Lens group 2E (G2E) helps correct the image plane position.

[0085] exist Figure 1 In the image, arrows below each lens group that moves during zooming indicate the approximate direction of movement from the wide-angle end to the telephoto end, while grounding marks are shown below each lens group that is fixed during zooming. Figure 1 In the example, the first optical system G1 and lens L2n are fixed relative to the image plane on the reduced side during zooming, therefore... Figure 1 In the diagram, the first optical system G1 and the lens L2n are enclosed in parentheses, and a grounding symbol is shown below them.

[0086] The zoom lens preferably comprises six lens groups. Furthermore, it is preferable that the lens group on the magnification side of the zoom lens has positive refractive power and is fixed relative to the image plane on the reduction side during zooming. Preferably, the lens group on the reduction side of the zoom lens has positive refractive power and is fixed relative to the image plane on the reduction side during zooming. By fixing the lens group on the magnification side during zooming, a lens structure can be formed where the overall length of the zoom lens remains unchanged. By fixing the lens group on the reduction side during zooming, it is easier to reduce aberration variations during zooming while maintaining the telecentricity of the reduction side. Figure 1 In the example, the lens group on the magnification side of the zoom lens includes the first optical system G1 and lens L2n, and the lens group on the reduction side of the zoom lens is the second lens group G2A.

[0087] The above structure and Figure 1The example shown is a zoom lens of the present invention. The number of lenses included in the first optical system G1 and the second optical system G2 of the zoom lens of the present invention, and the number of lenses included in each lens group of the second optical system G2, can also be set to be the same as... Figure 1 The examples shown have different numbers.

[0088] Including the structures related to the conditional expressions, the above-mentioned preferred structures and available structures can be combined arbitrarily, and are preferably selected appropriately according to the required specifications. In addition, the range of available conditional expressions is not limited to the conditional expressions described in the form of formulas, but includes the range obtained by arbitrarily combining the lower limit and the upper limit from the preferred and more preferred conditional expressions.

[0089] As an example, a preferred embodiment of the zoom lens of the present invention includes a first optical system G1 and a second optical system G2 sequentially along the optical path from the magnification side to the reduction side. The second optical system G2 forms an intermediate image MI at a position conjugate with the imaging plane on the reduction side. The first optical system G1 re-images the intermediate image MI onto the imaging plane on the magnification side. The zoom lens includes a lens on the magnification side of the optical path of the first optical system G1. When the group whose interval in the optical axis Z direction changes with the adjacent group during zooming is set as a lens group, the second optical system G2 includes a plurality of lens groups that move during zooming. One of the plurality of lens groups that moves during zooming is a lens group with an aperture diaphragm St that determines the numerical aperture. The lens group with aperture diaphragm St has negative refractive power. The zoom lens is a zoom lens that satisfies the above condition (1).

[0090] Next, embodiments of the zoom lens according to the technology of the present invention will be described. Furthermore, the reference numerals used in the cross-sectional views of each embodiment are used independently for each embodiment to avoid increasing the number of reference numerals and complicating the description and drawings. Therefore, even if the same reference numerals are used in the drawings of different embodiments, the structures are not necessarily the same.

[0091] [Example 1]

[0092] A cross-sectional view of the lens structure and beam of the zoom lens in Example 1 is shown in... Figure 1 Its structure and illustration method are as described above, therefore some repetitive descriptions are omitted here. The zoom lens of Embodiment 1 includes a first optical system G1 and a second optical system G2 sequentially from the magnification side to the reduction side. An intermediate image MI is formed in the optical path between the first optical system G1 and the second optical system G2.

[0093] The first optical system G1, from the reduction side to the magnification side, includes a mirror R1, lenses L1a to L1f, a mirror R2, and lenses L1g to L11. The second optical system G2, from the reduction side to the magnification side, includes lens group G2A (2A), lens group G2B (2B), lens group G2C (2C), lens group G2D (2D), lens group G2E (2E), and lens L2n. Lens group G2A includes lens L2a. Lens group G2B includes lenses L2b to L2d. Lens group G2C includes lenses L2e to L2h and an aperture St. Lens group G2D includes lens L2i. Lens group G2E includes lenses L2j to L2m.

[0094] During zooming, the second lens group G2B, the second lens group G2C, the second lens group G2D, and the second lens group G2E change their spacing with the adjacent groups along the optical axis Z and move along the optical axis Z, while the second lens group G2A, the lens L2n, and the first optical system G1 are fixed relative to the reduced-side imaging plane.

[0095] The zoom lens of Example 1 includes six lens groups.

[0096] The zoom lens of Embodiment 1 has two focusing groups. The first focusing group includes a combined lens formed by joining lenses L1d and L1e. The second focusing group includes a single lens L1f. During focusing, the first and second focusing groups move by changing their relative spacing in the Z-direction of the optical axis.

[0097] Regarding the zoom lens of Embodiment 1, basic lens data is shown in Tables 1A and 1B, specifications and variable surface spacing are shown in Table 2, and aspherical coefficients are shown in Table 3. To avoid making one table too long, the basic lens data is presented in two separate tables, Tables 1A and 1B. Table 1A shows the first optical system G1, and Table 1B shows the second optical system G2 and optical component PP. The descriptions of mirrors R1 and R2 are omitted from the basic lens data.

[0098] Tables 1A and 1B are described as follows: Column Sn shows the surface numbering with the surface closest to the magnification side as surface number 1, increasing sequentially towards the reduction side. Column R shows the radius of curvature of each surface. Column D shows the surface spacing along the optical axis Z between each surface and the surface adjacent to its reduction side. Column Nd shows the refractive index of each component relative to the d-line. Column νd shows the dispersion coefficient of each component based on the d-line reference.

[0099] In Tables 1A and 1B, the radius of curvature of the convex face facing the magnification side is marked positive, and the radius of curvature of the convex face facing the reduction side is marked negative. In Table 1B, the face number and the term (St) are recorded in the face number column corresponding to the aperture St. The bottom column of D in Table 1B shows the interval between the face closest to the reduction side and the image display face Sim. In Table 1B, the notation DD[] is used for the variable face interval during zooming, with the face number of the magnification side marked in [] and recorded in column D.

[0100] Table 2 shows the zoom ratio Zr, absolute value of focal length |f|, F-number FNo., maximum full angle of view 2ω, and variable plane interval during zoom, with the d-line as the reference. The (°) in the 2ω column indicates the unit as degrees. In Table 2, the values ​​for the wide-angle, intermediate focal length, and telephoto ends are shown in the WIDE, MIDDLE, and TELE columns, respectively.

[0101] In the basic lens data, aspherical surfaces are marked with an asterisk (*), and the paraxial radius of curvature is recorded in the radius of curvature column. In Table 3, the surface number of the aspherical surface is shown in row Sn, and the aspherical coefficient values ​​for each aspherical surface are shown in rows KA and Am (m = 3, 4, 5, ... 20). The aspherical coefficient values ​​in Table 3, where "E±n" (n: an integer), represent "×10⁻¹⁰". ±n KA and Am are the aspheric coefficients in the aspheric formula expressed by the following equation.

[0102] Zd=C×h 2 / {1+(1-KA×C 2 ×h 2 ) 1 / 2}+∑Am×h m

[0103] in,

[0104] Zd: Aspherical depth (the length of the perpendicular line from a point on the aspherical surface at height h to a plane tangent to the vertex of the aspherical surface and perpendicular to the optical axis Z);

[0105] h: Height (distance from the optical axis Z to the lens surface);

[0106] C: The reciprocal of the paraxial radius of curvature;

[0107] KA, Am: Aspheric coefficients

[0108] In aspherical form, ∑ represents the summation related to m.

[0109] The following tables and aberration diagrams are based on data with the absolute value of the zoom lens's focal length standardized to 1.0. Furthermore, the tables below contain values ​​rounded to a specified number of decimal places.

[0110] [Table 1A]

[0111] Example 1

[0112] *1 -7.9757 1.3547 1.53158 55.08 *2 -19.9590 0.1991 3 16.9980 0.4181 1.65160 58.55 4 4.8930 1.6622 5 11.6420 0.2989 1.72916 54.68 6 4.3701 1.4660 7 149.0346 0.2631 1.62041 60.29 8 5.6460 1.3883 9 -7.1486 2.1909 1.80400 46.58 10 -9.8201 0.0683 11 23.7198 1.6428 1.80400 46.58 12 -15.4185 8.0449 13 -26.9833 0.7435 1.80809 22.76 14 -9.8236 2.2186 15 16.3092 2.5350 1.43875 94.66 16 -6.3457 0.2390 1.80518 25.42 17 -9.7816 0.5750 18 58.6136 0.2389 1.84666 23.78 19 6.0897 3.0893 1.49700 81.61 20 -10.1069 0.4064 *21 -14.0034 1.2947 1.51633 64.06 *22 -7.9676 12.9665

[0113] [Table 1B]

[0114] Example 1

[0115] 23 12.7770 2.7908 1.80400 46.58 24 -67.9187 DD

[24] 25 -12.7865 0.7973 1.76182 26.52 26 19.8908 1.7401 27 -24.3688 2.8456 1.80518 25.42 28 -10.1039 0.0669 29 8.8486 2.9878 1.80400 46.58 30 55.2923 1.0399 31 -40.0531 0.5833 1.58913 61.13 32 7.7005 DD

[32] 33 66.8494 0.6165 1.74950 35.28 34 -17.5390 DD

[34] 35 (St) ∞ 0.0398 36 6.3527 1.2626 1.71299 53.87 37 -9.1210 0.0433 38 -8.6530 0.1990 1.72825 28.46 39 5.3173 1.8227 40 -4.9106 0.1993 1.59551 39.24 41 -28.0943 0.0399 42 23.2312 1.2000 1.43875 94.66 43 -6.1829 DD

[43] 44 8.6535 1.6603 1.43875 94.66 45 -9.6853 1.7639 46 -6.8345 0.2591 1.80440 39.58 47 -229.5082 0.1678 48 92.6481 0.8133 1.80809 22.76 49 -13.7749 DD

[49] 50 18.1202 1.5782 1.89286 20.36 51 -38.9136 2.5297 52 ∞ 4.9797 1.51633 64.14 53 ∞ 0.2091 1.51633 64.14 54 ∞ 0.0281

[0116] [Table 2]

[0117] Example 1

[0118] Zr 1.0 1.5 2.0 |f| 1.0 1.5 2.0 FNo. 2.41 2.41 2.41 2ω(°) 138.2 119.8 105.0 DD

[24] 4.17 3.55 4.41 DD

[32] 11.03 5.14 1.29 DD

[34] 0.10 3.02 3.49 DD

[43] 1.40 1.52 0.10 DD

[49] 0.14 3.62 7.56

[0119] [Table 3]

[0120] Example 1

[0121] KA -7.129065340664E-01 -2.204817460317E+02 A3 -2.509951819645E-02 -2.245277947389E-02 A4 2.258436836102E-02 1.241673597306E-02 A5 -4.096320252373E-03 1.410527979700E-03 A6 -4.752216522031E-04 -1.665522743497E-03 A7 2.597946080504E-04 1.715724635863E-04 A8 -1.597189973087E-05 6.676392268753E-05 A9 -6.159960818290E-06 -1.330846446231E-05 A10 9.840639048696E-07 -1.245990859684E-06 A11 4.435108517789E-08 4.447495802803E-07 A12 -1.930483863599E-08 2.894812052222E-09 A13 5.796891498290E-10 -7.971322196388E-09 A14 1.757316627263E-10 2.720298518076E-10 A15 -1.292604163406E-11 8.009834424488E-11 A16 -6.440870908161E-13 -4.630612566504E-12 A17 8.739781649411E-14 -4.262215753627E-13 A18 -3.722668267112E-16 3.143560736371E-14 A19 -2.082787628359E-16 9.357882986130E-16 A20 5.928701551861E-18 -8.023474940400E-17

[0122] KA 1.000000000000E+00 1.000000000000E+00 A3 -1.652482317395E-03 -1.634619468535E-04 A4 4.262262390267E-03 2.407662445817E-03 A5 -3.311474741143E-03 4.720777327140E-04 A6 7.629203757756E-04 -1.250525443159E-03 A7 6.170352742780E-04 7.067276324267E-04 A8 -4.258175688881E-04 -3.593643144892E-05 A9 1.779789692480E-05 -1.177064185369E-04 A10 4.941300082479E-05 3.357853251978E-05 A11 -9.696537862207E-06 6.267509280947E-06 A12 -2.498293596301E-06 -3.778376867355E-06 A13 8.351601644683E-07 8.376855331413E-08 A14 4.490316418728E-08 1.797909778427E-07 A15 -3.319840215799E-08 -1.991769429656E-08 A16 7.248700740760E-10 -3.615061185259E-09 A17 6.475987028654E-10 6.798146764034E-10 A18 -3.909579259759E-11 1.204961706620E-11 A19 -5.021301271375E-12 -7.438651563275E-12 A20 4.158362201971E-13 3.278064091599E-13

[0123] Figure 2 The diagram shows the aberrations of the zoom lens in Example 1. Figure 2 In the diagram, the upper section marked "WIDE" shows the aberration maps at the wide-angle end, the middle section marked "MIDDLE" shows the aberration maps at the intermediate focal length, and the lower section marked "TELE" shows the aberration maps at the telephoto end. Figure 2 In the diagram, from left to right, spherical aberration, astigmatism, distortion aberration, and chromatic aberration are shown. In the spherical aberration diagram, aberrations related to the d-line, C-line, and F-line are shown using solid lines, long dashed lines, and short dashed lines, respectively. In the astigmatism diagram, aberrations related to the d-line in the sagittal direction are shown using solid lines, and aberrations related to the d-line in the meridional direction are shown using short dashed lines. In the distortion aberration diagram, aberrations related to the d-line are shown using solid lines. In the chromatic aberration diagram, aberrations related to the C-line and F-line are shown using long dashed lines and short dashed lines, respectively. In the spherical aberration diagram, the F-value is shown after "FNo.=". In the other aberration diagrams, the value of the maximum half-angle is shown after "ω=". Figure 2 The data shown is when the distance on the optical axis Z from the magnified side imaging plane to the first optical system G1 is 149.9.

[0124] Unless otherwise specified, the notation, meaning, recording method, illustration method, and the point for standardizing the absolute value of the focal length to 1.0 for the data related to Embodiment 1 above are the same in the following embodiments, so repeated descriptions are omitted below.

[0125] [Example 2]

[0126] A cross-sectional view of the lens structure and beam of the zoom lens in Example 2 is shown. Figure 3 The zoom lens of Embodiment 2 includes a first optical system G1 and a second optical system G2 sequentially from the magnification side to the reduction side. An intermediate image MI is formed in the optical path between the first optical system G1 and the second optical system G2.

[0127] The first optical system G1, from the reduction side to the magnification side, includes a mirror R1, lenses L1a to L1f, a mirror R2, and lenses L1g to L1l. The second optical system G2, from the reduction side to the magnification side, includes lens group G2A (2A), lens group G2B (2B), lens group G2C (2C), lens group G2D (2D), lens group G2E (2E), and lens L2n. Lens group G2A includes lens L2a. Lens group G2B includes lenses L2b to L2d. Lens group G2C includes lenses L2e to L2h and an aperture St. Lens group G2D includes lens L2i. Lens group G2E includes lenses L2j to L2m.

[0128] During zooming, the second lens group G2B, the second lens group G2C, the second lens group G2D, and the second lens group G2E change their spacing along the optical axis Z with adjacent groups and move along the optical axis Z, while the second lens group G2A, lens L2n, and the first optical system G1 remain fixed relative to the reduced-side imaging plane. The zoom lens of Embodiment 2 includes six lens groups.

[0129] The zoom lens of Embodiment 2 has two focusing groups. The first focusing group includes a combined lens formed by joining lenses L1d and L1e. The second focusing group includes a single lens, L1f. During focusing, the first and second focusing groups move by changing their relative spacing along the optical axis Z.

[0130] Regarding the zoom lens of Example 2, basic lens data are shown in Tables 4A and 4B, specifications and variable surface spacing are shown in Table 5, aspherical coefficients are shown in Table 6, and aberrations are illustrated when the distance on the optical axis Z from the magnified imaging plane to the first optical system G1 is 149.9. Figure 4 .

[0131] [Table 4A]

[0132] Example 2

[0133] *1 -7.9076 1.3546 1.53158 55.08 *2 -19.9175 0.2181 3 17.2973 0.4184 1.65160 58.55 4 4.8848 1.6665 5 11.6684 0.2987 1.72916 54.68 6 4.4400 1.4227 7 88.9615 0.2629 1.62041 60.29 8 5.4548 1.4208 9 -7.1277 2.1911 1.80400 46.58 10 -9.9889 0.0400 11 23.6527 1.9992 1.80400 46.58 12 -15.0803 8.0439 13 -28.9479 0.7360 1.80809 22.76 14 -10.2122 2.3604 15 16.3823 2.5770 1.43875 94.66 16 -6.4053 0.2389 1.80518 25.42 17 -9.8310 0.6302 18 70.7006 0.2390 1.84666 23.78 19 6.1370 3.0894 1.49700 81.61 20 -10.2160 0.3633 *21 -14.7847 1.2947 1.51633 64.06 *22 -7.9671 12.9465

[0134] [Table 4B]

[0135] Example 2

[0136] 23 12.2561 2.9461 1.80400 46.58 24 -77.2390 DD

[24] 25 -13.1151 0.7966 1.76182 26.52 26 17.9625 1.5051 27 -26.2823 2.9875 1.80518 25.42 28 -10.1815 0.0398 29 8.7624 2.9875 1.80400 46.58 30 66.9962 0.6301 31 -47.8103 0.5977 1.58913 61.13 32 7.6424 DD

[32] 33 57.3316 0.6138 1.74950 35.28 34 -18.0316 DD

[34] 35 (St) ∞ 0.0399 36 6.3073 1.2424 1.69680 55.53 37 -8.7478 0.0325 38 -8.3849 0.1994 1.72825 28.46 39 5.3492 1.3257 40 -4.8791 0.2289 1.59551 39.24 41 -99.1629 0.0398 42 21.6115 1.1998 1.45650 90.27 43 -6.1365 DD

[43] 44 8.7291 1.6773 1.43875 94.66 45 -9.1683 2.0061 46 -6.3378 0.2590 1.80610 40.93 47 -62.3793 0.0397 48 78.8909 0.8488 1.80809 22.76 49 -12.9390 DD

[49] 50 17.5899 1.7795 1.89286 20.36 51 -39.8773 2.5295 52 ∞ 4.9794 1.51633 64.14 53 ∞ 0.2091 1.51633 64.14 54 ∞ 0.0256

[0137] [Table 5]

[0138] Example 2

[0139] Zr 1.0 1.5 2.0 |f| 1.0 1.5 2.0 FNo. 2.41 2.41 2.41 2ω(°) 138.0 119.8 105.0 DD

[24] 3.97 3.37 4.05 DD

[32] 11.62 5.54 1.70 DD

[34] 0.10 3.37 3.86 DD

[43] 0.93 1.19 0.10 DD

[49] 0.20 3.36 7.11

[0140] [Table 6]

[0141] Example 2

[0142] KA -7.125250585192E-01 -2.173295965806E+02 A3 -2.657126629107E-02 -2.418919615761E-02 A4 2.356606744837E-02 1.349906820549E-02 A5 -4.245786345567E-03 1.362228474816E-03 A6 -5.162727724147E-04 -1.767331906448E-03 A7 2.752325033301E-04 1.898029436868E-04 A8 -1.627533562437E-05 7.076993010844E-05 A9 -6.674186860013E-06 -1.450082941842E-05 A10 1.044996133028E-06 -1.310692750019E-06 A11 5.072944254625E-08 4.836599399743E-07 A12 -2.090803822290E-08 2.536591745737E-09 A13 5.920753226630E-10 -8.687859824519E-09 A14 1.938450386881E-10 3.021568264466E-10 A15 -1.396230021405E-11 8.765369074892E-11 A16 -7.281086785739E-13 -5.098366689812E-12 A17 9.641868103882E-14 -4.687961676866E-13 A18 -3.591446974526E-16 3.464000300969E-14 A19 -2.335100345004E-16 1.035201480596E-15 A20 6.651692452794E-18 -8.868687215940E-17

[0143] KA 1.000000000000E+00 1.000000000000E+00 A3 -1.189160703338E-03 -1.628371982061E-05 A4 3.784162623285E-03 2.309512669279E-03 A5 -3.136536619849E-03 3.694382302366E-04 A6 8.083760079830E-04 -1.187935194638E-03 A7 5.594606187786E-04 7.151358269646E-04 A8 -4.097788541675E-04 -4.834447517677E-05 A9 2.078851519349E-05 -1.162013917055E-04 A10 4.641278203757E-05 3.449328475274E-05 A11 -9.301616560602E-06 5.998712500760E-06 A12 -2.301321238618E-06 -3.784975255597E-06 A13 7.782930262603E-07 9.764923152176E-08 A14 4.024042409897E-08 1.775748966613E-07 A15 -3.036398806511E-08 -2.009278273694E-08 A16 6.773987056164E-10 -3.516265516632E-09 A17 5.830632731873E-10 6.742979303452E-10 A18 -3.516127760951E-11 1.072830403458E-11 A19 -4.456246692072E-12 -7.312585479508E-12 A20 3.676228474631E-13 3.292049531661E-13

[0144] [Example 3]

[0145] A cross-sectional view of the lens structure and beam of the zoom lens in Example 3 is shown. Figure 5 The zoom lens of Embodiment 3 includes a first optical system G1 and a second optical system G2 sequentially from the magnification side to the reduction side. An intermediate image MI is formed in the optical path between the first optical system G1 and the second optical system G2.

[0146] The first optical system G1, from the reduction side to the magnification side, includes a mirror R1, lenses L1a to L1f, a mirror R2, and lenses L1g to L11. The second optical system G2, from the reduction side to the magnification side, includes lens group G2A, lens group G2B, lens group G2C, lens group G2D, and lens group G2E. Lens group G2A includes lens L2a. Lens group G2B includes lenses L2b to L2d. Lens group G2C includes lenses L2e to L2h and an aperture St. Lens group G2D includes lens L2i. Lens group G2E includes lenses L2j to L2n.

[0147] During zooming, the second lens group G2B, the second lens group G2C, the second lens group G2D, and the second lens group G2E change their spacing along the optical axis Z with adjacent groups and move along the optical axis Z, while the second lens group G2A and the first optical system G1 remain fixed relative to the reduced-side imaging plane. The zoom lens of Embodiment 3 includes six lens groups.

[0148] The zoom lens of Embodiment 3 has two focusing groups. The first focusing group includes a combined lens formed by joining lenses L1d and L1e. The second focusing group includes a single lens, L1f. During focusing, the first and second focusing groups move by changing their relative spacing along the optical axis Z.

[0149] Regarding the zoom lens of Example 3, basic lens data are shown in Tables 7A and 7B, specifications and variable surface spacing are shown in Table 8, aspherical coefficients are shown in Table 9, and aberrations are illustrated when the distance on the optical axis Z from the magnified imaging plane to the first optical system G1 is 149.9. Figure 6 .

[0150] [Table 7A]

[0151] Example 3

[0152] *1 -7.7773 1.3543 1.53158 55.08 *2 -19.9137 0.3001 3 16.9882 0.4180 1.65160 58.54 4 4.9067 1.6495 5 11.4032 0.3064 1.74400 44.79 6 4.3865 1.2669 7 21.5939 0.2630 1.62041 60.29 8 4.9047 1.6054 9 -6.2095 2.1717 1.80400 46.58 10 -9.0057 0.0398 11 24.8432 2.1905 1.80400 46.58 12 -14.4209 8.0472 13 -29.5479 0.9253 1.80809 22.76 14 -10.4383 2.3949 15 15.8711 2.4848 1.43875 94.66 16 -6.4292 0.2391 1.84666 23.78 17 -9.5453 0.3836 18 61.0100 0.5169 1.84666 23.78 19 6.1359 3.0886 1.49700 81.61 20 -10.2921 0.6647 *21 -14.4261 1.2942 1.51633 64.06 *22 -7.9656 DD

[22]

[0153] [Table 7B]

[0154] Example 3

[0155] 23 11.3838 3.2020 1.80610 40.93 24 -157.8296 3.8103 25 -13.4818 0.6763 1.80518 25.42 26 18.1126 1.3192 27 -31.7601 2.3193 1.78880 28.43 28 -9.6429 0.0399 29 8.5913 2.9870 1.80400 46.58 30 61.4199 0.4848 31 -28.6898 0.5974 1.58313 59.37 32 7.4830 DD

[32] 33 34.9149 0.6666 1.80518 25.42 34 -15.9409 DD

[34] 35 (St) ∞ 0.2116 36 6.4936 1.2196 1.69680 55.53 37 -8.9573 0.0562 38 -8.1966 0.1991 1.80000 29.84 39 5.3859 1.1389 40 -5.2873 0.7995 1.75520 27.51 41 -38.2306 0.0399 42 15.3762 1.5747 1.43875 94.66 43 -6.0942 DD

[43] 44 10.3280 1.6603 1.45650 90.27 45 -9.6949 2.6221 46 -6.0964 0.2591 1.74950 35.28 47 -82.3001 0.0400 48 65.8405 0.8658 1.80809 22.76 49 -13.6500 DD

[49] 50 12.1608 1.9089 1.89286 20.36 51 -467.0656 2.5291 52 ∞ 4.9785 1.51633 64.14 53 ∞ 0.2091 1.51633 64.14 54 ∞ 0.0268

[0156] [Table 8]

[0157] Example 3

[0158] Zr 1.0 1.5 2.0 |f| 1.0 1.5 2.0 FNo. 2.41 2.41 2.41 2ω(°) 138.0 119.8 105.0 DD

[22] 13.05 13.58 14.27 DD

[32] 10.77 4.64 1.12 DD

[34] 0.32 1.93 2.24 DD

[43] 0.10 0.74 0.10 DD

[49] 0.10 3.45 6.60

[0159] [Table 9]

[0160] Example 3

[0161] KA -6.644507793526E-01 -1.726211138561E+02 A3 -2.691792214400E-02 -2.353330321822E-02 A4 2.408475058936E-02 1.377690424065E-02 A5 -4.337276061487E-03 1.379587272547E-03 A6 -5.397187080221E-04 -1.842175511015E-03 A7 2.843400241519E-04 2.012261487425E-04 A8 -1.640774845587E-05 7.511202368230E-05 A9 -6.984518854812E-06 -1.559825231919E-05 A10 1.079986170871E-06 -1.417994104354E-06 A11 5.463037850055E-08 5.297773088324E-07 A12 -2.185472715226E-08 2.788990627693E-09 A13 6.014346930959E-10 -9.693592978523E-09 A14 2.045222440524E-10 3.397266058514E-10 A15 -1.465158442295E-11 9.961967076840E-11 A16 -7.742007962859E-13 -5.839076997376E-12 A17 1.024742526925E-13 -5.426525257601E-13 A18 -3.952739375672E-16 4.041220269823E-14 A19 -2.506764309537E-16 1.220331971306E-15 A20 7.234390247682E-18 -1.053877620354E-16

[0162] KA 1.000000000000E+00 1.000000000000E+00 A3 -1.461840245686E-03 2.595833113763E-04 A4 3.713068904568E-03 1.774560048339E-03 A5 -2.795471687902E-03 7.981455290682E-04 A6 7.766198648758E-04 -1.109207084608E-03 A7 4.572337710741E-04 5.821819354564E-04 A8 -3.756090850682E-04 -3.683337619356E-05 A9 2.933875527057E-05 -9.846037864989E-05 A10 4.064843093390E-05 3.069889362280E-05 A11 -9.200164135374E-06 4.807880062866E-06 A12 -1.885780170356E-06 -3.386621776220E-06 A13 7.232281596103E-07 1.301400446832E-07 A14 2.652896176383E-08 1.571777318993E-07 A15 -2.712995802792E-08 -1.977600926304E-08 A16 8.213281359321E-10 -3.003811506462E-09 A17 5.042468966683E-10 6.398296062980E-10 A18 -3.297326506632E-11 5.674705297861E-12 A19 -3.740390117812E-12 -6.819011287975E-12 A20 3.223379097188E-13 3.300939480085E-13

[0163] Table 10 shows the corresponding values ​​of conditional expressions (1) to (6) for the zoom lenses of Examples 1 to 3. Table 10 shows the values ​​with the d-line as the reference.

[0164] [Table 10]

[0165]

[0166]

[0167] As can be seen from the above data, the zoom lenses of Examples 1 to 3 have a maximum full angle of view of more than 125 degrees at the wide-angle end, have a wide angle of view, a zoom ratio of more than 1.5x, have a high magnification, and the F value is less than 2.5 and constant throughout the entire zoom range. All aberrations are well corrected, thus achieving high optical performance.

[0168] Next, the projection display device according to the embodiments of the present invention will be described. Figure 7 This is a schematic structural diagram of a projection-type display device according to an embodiment of the present invention. Figure 7 The projection display device 100 shown includes a zoom lens 10, a light source 15, transmissive display elements 11a-11c corresponding to each color of light as light valves, dichroic mirrors 12 and 13 for color separation, a cross-shaped dichroic prism 14 for color synthesis, condenser lenses 16a-16c, and total internal reflection mirrors 18a-18c for deflecting the light path, as described in the embodiments of the present invention. Figure 7 The zoom lens 10 is schematically illustrated in the diagram. Furthermore, an integrator is positioned between the light source 15 and the dichroic mirror 12, but... Figure 7 Its illustration is omitted.

[0169] White light from light source 15 is split into three colored light beams (green, blue, and red) in dichroic mirrors 12 and 13. These beams are then modulated by condenser lenses 16a-16c and incident on transmissive display elements 11a-11c, which correspond to each colored light beam. After color synthesis by cross-shaped dichroic prism 14, the light is incident on zoom lens 10. Zoom lens 10 projects an optical image based on the modulated light from transmissive display elements 11a-11c onto screen 105.

[0170] Figure 8 This is a schematic structural diagram of a projection-type display device according to another embodiment of the present invention. Figure 8 The projection display device 200 shown includes a zoom lens 210, a light source 215, DMD (Digital Micromirror Device) elements 21a-21c serving as light valves corresponding to each color of light, TIR (Total Internal Reflection) prisms 24a-24c for color separation and color synthesis, and a polarizing light separating prism 25 for separating illumination light and projection light, as described in the embodiments of the present invention. Figure 8 The zoom lens 210 is schematically illustrated in the diagram. Furthermore, an integrator is positioned between the light source 215 and the polarizing beam separator 25, but... Figure 8 Its illustration is omitted.

[0171] White light from light source 215 is reflected by the reflective surface inside polarization-splitting prism 25 and then decomposed into three colored light beams (green, blue, and red) by TIR prisms 24a-24c. Each of the decomposed colored light beams is modulated by its corresponding DMD element 21a-21c, and then undergoes color synthesis again in the opposite direction within the TIR prisms 24a-24c before being transmitted through polarization-splitting prism 25 and incident on zoom lens 210. Zoom lens 210 projects an optical image based on the modulated light from DMD elements 21a-21c onto screen 205.

[0172] Figure 9 This is a schematic structural diagram of a projection-type display device according to another embodiment of the present invention. Figure 9 The projection display device 300 shown includes a zoom lens 310, a light source 315, reflective display elements 31a-31c corresponding to each color of light as light valves, dichroic mirrors 32 and 33 for color separation, a cross-shaped dichroic prism 34 for color synthesis, a total reflection mirror 38 for deflecting the light path, and polarization separation prisms 35a-35c, as described in the embodiments of the present invention. Figure 9 The zoom lens 310 is shown in a schematic diagram. Furthermore, an integrator is positioned between the light source 315 and the dichroic mirror 32, but... Figure 9 Its illustration is omitted.

[0173] White light from light source 315 is split into three colored light beams (green, blue, and red) by dichroic mirrors 32 and 33. Each of the split colored light beams passes through polarizing prisms 35a-35c and is modulated by reflective display elements 31a-31c corresponding to each colored light beam. After color synthesis by a cross-shaped dichroic prism 34, the light is incident on zoom lens 310. Zoom lens 310 projects an optical image based on the modulated light from reflective display elements 31a-31c onto screen 305.

[0174] Figure 10 and Figure 11 This is an external view of a camera 400, a camera device according to one embodiment of the present invention. Figure 10 This is a stereoscopic view of camera 400 as seen from the front side. Figure 11 This is a perspective view of the camera 400 as seen from the rear side. The camera 400 is a mirrorless single-lens digital camera with an interchangeable lens 48 that can be easily mounted. The interchangeable lens 48 houses a zoom lens 49 according to an embodiment of the present invention within its lens barrel.

[0175] The camera 400 includes a camera body 41, and a shutter button 42 and a power button 43 are provided on the upper surface of the camera body 41. Furthermore, an operation unit 44, an operation unit 45, and a display unit 46 are provided on the back of the camera body 41. The display unit 46 displays the captured image and the image existing within the field of view before shooting.

[0176] A camera aperture for light from the subject is provided at the center of the front surface of the camera body 41. A bayonet 47 is provided at the position corresponding to the camera aperture, and an interchangeable lens 48 is mounted on the camera body 41 via the bayonet 47.

[0177] The camera body 41 contains an imaging element (not shown), such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor), which outputs an imaging signal corresponding to the image of the subject formed by the interchangeable lens 48; a signal processing circuit (not shown) that processes the imaging signal output from the imaging element and generates an image; and a recording medium (not shown) for recording the generated image. In the camera 400, by pressing the shutter button 42, still images or moving images can be captured, and the image data obtained is recorded in the aforementioned recording medium.

[0178] The above description, through examples and embodiments, illustrates the technology of the present invention. However, the technology of the present invention is not limited to the above examples and embodiments, and various modifications are possible. For example, the radius of curvature, interplanar spacing, refractive index, dispersion coefficient, and aspherical coefficient of each lens are not limited to the values ​​shown in the numerical embodiments above, and other values ​​may be used.

[0179] Furthermore, the projection display device involved in the technology of this invention is not limited to the above-described structure. For example, the optical components and light valves used for beam separation or beam combining can be modified in various ways. The light valve is not limited to a method of outputting an optical image based on image data by spatially modulating light from a light source through an image display element; it can also be a method of outputting an optical image based on image data by using the light itself output from a self-emissive image display element. Examples of white-emitting image display elements include image display elements composed of two-dimensionally arranged light-emitting elements such as LEDs (Light Emitting Diodes) or OLEDs (Organic Light Emitting Diodes).

[0180] Furthermore, the imaging device involved in the technology of the present invention is not limited to the above-described structure, and can be configured in various ways such as a camera other than a mirrorless camera, a film camera, a video camera, and a movie camera.

[0181] Symbol Explanation

[0182] 10, 49, 210, 310 - Zoom lens; 11a-11c - Transmissive display element; 12, 13, 32, 33 - Dichroic mirror; 14, 34 - Cross-shaped dichroic prism; 15, 215, 315 - Light source; 16a-16c - Condenser lens; 18a-18c, 38 - Total reflection mirror; 21a-21c - DMD element; 24a-24c - TIR prism; 25, 35a-35c - Polarizing prism; 31a-31c - Reflective display element; 41 - Camera body; 42 - Shutter button; 43 - Power button; 44, 45 - Operation unit; 46 - Display unit; 47 - Bayonet mount 48 - Interchangeable lens; 100, 200, 300 - Projection display device; 105, 205, 305 - Screen; 400 - Camera; G1 - First optical system; G2 - Second optical system; G2A - Second A lens group; G2B - Second B lens group; G2C - Second C lens group; G2D - Second D lens group; G2E - Second E lens group; Ka - On-axis beam; Kb - Beam with maximum viewing angle; L1a~L11, L2a~L2n - Lenses; MI - Intermediate image; PP - Optical component; R1 - Mirror; R2 - Mirror; Sim - Image display surface; St - Aperture; Z - Optical axis.

Claims

1. A zoom lens, comprising, sequentially from the magnification side to the reduction side along the optical path, a first optical system and a second optical system. The second optical system forms an intermediate image at a position conjugate with the image plane on the reduced side. The first optical system re-images the intermediate image onto the magnified imaging plane. The zoom lens includes a lens on the magnification side of the optical path of the first optical system. When a lens group is defined as a lens group whose optical axis spacing changes during zooming, The second optical system includes multiple lens groups that move during zooming. One of the multiple lens groups that moves during zooming is a lens group with an aperture diaphragm that determines the numerical aperture. The lens group with the aforementioned aperture has negative refractive power. When the focal length of the lens group having the aforementioned aperture is set to fAp, When the focal length of the second optical system at the wide-angle end is set to f2w... The zoom lens satisfies the following condition (1). 0.1<f2w / fAp<2.1 (1), The first optical system, from the reduction side to the magnification side, consists of a first reflecting mirror, six lenses, a second reflecting mirror, and six lenses in sequence. The second optical system, from the reduction side to the magnification side, consists of lens group 2A, lens group 2B, lens group 2C, lens group 2D, lens group 2E, and one lens. The second lens group A consists of one lens, the second lens group B consists of three lenses, the second lens group C consists of four lenses and the aperture diaphragm, the second lens group D consists of one lens, and the second lens group E consists of four lenses. or, The second optical system, from the reduction side to the magnification side, consists of lens groups 2A, 2B, 2C, 2D, and 2E in sequence. The second lens group consists of one lens, the second lens group consists of three lenses, the second lens group consists of four lenses and the aperture, the second lens group consists of one lens, and the second lens group consists of five lenses.

2. The zoom lens according to claim 1, wherein, The difference in the optical axis direction between the position of the lens group with the aperture at the wide-angle end and the position of the lens group with the aperture at the telephoto end is defined as ZAp. When the focal length of the zoom lens at the wide-angle end is set to fw, The zoom lens satisfies the following condition (2). 4<ZAp / |fw|<10 (2)。 3. The zoom lens according to claim 1 or 2, wherein, When the average of the dispersion coefficients of the d-line reference of all positive lenses included in the lens group having the aforementioned aperture is set to νAp, The zoom lens satisfies the following condition (3). 65<νAp (3).

4. The zoom lens according to claim 1 or 2, wherein, When zooming in, the aperture diameter of the aperture is variable. The numerical aperture of the zoom lens is constant throughout the zoom range.

5. The zoom lens according to claim 1 or 2, wherein, When the focal length of the zoom lens at the wide-angle end is set to fw, The zoom lens satisfies the following condition (4). -0.1<|fw| / f2w<0 (4).

6. The zoom lens according to claim 1 or 2, wherein, When the focal length of the lens group that moves during zooming is set to fR, and the lens group having the aperture is arranged adjacent to the lens group having the aperture on the narrowing side, The zoom lens satisfies the following condition (5). -1.2<fR / fAp<-0.1 (5).

7. The zoom lens according to claim 1 or 2, wherein, With the back focal length of the zoom lens at the wide-angle end set to Bfw on the reduced side of the aerodynamic telemetry, When the focal length of the zoom lens at the wide-angle end is set to fw, The zoom lens satisfies the following condition (6). 4<Bfw / |fw| (6)。 8. The zoom lens according to claim 1 or 2, wherein, The zoom lens comprises six lens groups. The lens group on the magnification side of the zoom lens has positive refractive power and remains fixed relative to the reduction side image plane during zooming. The lens group on the narrowest side of the zoom lens has positive refractive power and is fixed relative to the narrowing side image plane during zooming.

9. The zoom lens according to claim 1 or 2, wherein, The second optical system, from the side closest to the reduction to the side closest to the magnification, sequentially includes, along the optical path, the second A lens group with positive refractive power, the second B lens group with positive refractive power, the second C lens group with negative refractive power, the second D lens group with positive refractive power, and the second E lens group with refractive power. During zooming, the second lens group, the second lens group, the second lens group, the second lens group, and the second lens group change their spacing in the optical axis direction with the adjacent groups and move along the optical axis, while the second lens group is fixed relative to the reduced-side imaging plane.

10. The zoom lens according to claim 1 or 2, wherein, The first optical system includes multiple focusing groups on the optical path closer to the narrowed side than the maximum air gap of the first optical system at the wide-angle end. The multiple focusing groups move by changing the spacing between each other along their optical axes, thereby achieving focusing.

11. The zoom lens according to claim 1, which satisfies the following condition (1-1). 0.2<f2w / fAp<1.8 (1-1).

12. The zoom lens according to claim 2, which satisfies the following condition (2-1). 4.7<ZAp / |fw|<8 (2-1).

13. The zoom lens according to claim 3, which satisfies the following condition (3-1). 70 < νAp < 90 (3-1).

14. The zoom lens according to claim 5, which satisfies the following condition (4-1). -0.06<|fw| / f2w<0 (4-1).

15. The zoom lens according to claim 6, which satisfies the following condition (5-1). -1<fR / fAp<-0.2 (5-1).

16. The zoom lens according to claim 7, which satisfies the following condition (6-1). 5<Bfw / |fw|<10 (6-1).

17. A projection display device, comprising: Optical valve, outputting optical image; and The zoom lens according to any one of claims 1 to 16, The zoom lens projects the optical image output from the light valve onto the screen.

18. A camera device comprising a zoom lens according to any one of claims 1 to 16.

Images