Zoom lens, projection-type display device, and imaging device

Abstract

The invention provides a wide-angle, high-zoom-ratio, compact and high-performance zoom lens which can well suppress aberration variation during zooming and focusing, 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 to the reduction side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a positive refractive power, a fourth lens group having a negative refractive power, an intermediate group including one or more lens groups, and a final lens group having a positive refractive power. The first lens group includes, in order from the magnification side to the reduction side, a 1A-th part group, a 1B-th part group, and a 1C-th part group of negative refractive power. During focusing, the interval between the 1B-th partial group and the adjacent partial group changes. The interval between the second lens group and the third lens group is shorter at the telephoto end than at the wide-angle end.

Description

Technical Field

[0001] The technology of the present invention relates to a zoom lens, a projection display device, and an imaging device. Background Art

[0002] Optical systems applicable to image projection devices are described in Patent Documents 1 and 2 below.

[0003] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2016-095395

[0004] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2015-212753

[0005] There is a demand for a zoom lens that has a wide angle, a high magnification ratio, is compactly configured, has well-suppressed aberration variations during zooming and focusing, and has high optical performance. These required levels are increasing year by year. Summary of the Invention

[0006] The present invention provides a zoom lens, a projection display device including the zoom lens, and an imaging device including the zoom lens. The zoom lens has a wide angle, a high magnification ratio, is compactly configured, has well-suppressed aberration variations during zooming and focusing, and has high optical performance.

[0007] One aspect of the present invention is a zoom lens that sequentially includes, from the magnifying side to the reducing side, a first lens group having a negative optical power, a second lens group having a positive optical power, a third lens group having a positive optical power, a fourth lens group having a negative optical power, an intermediate group including one or more lens groups, and a final lens group having a positive optical power. Among them, the first lens group sequentially includes a first A partial group, a first B partial group, and a first C partial group having a negative optical power from the magnifying side to the reducing side. During focusing, the interval between the first A partial group and the first B partial group changes, and the interval between the first B partial group and the first C partial group changes. During zooming, the first lens group and the final lens group do not move, and all the lens groups in the second lens group, the third lens group, the fourth lens group, and the intermediate group change the interval in the optical axis direction between adjacent lens groups and move along the optical axis. The interval between the second lens group and the third lens group at the telephoto end is shorter than the interval between the second lens group and the third lens group at the wide-angle end.

[0008] When the interval between the second lens group and the third lens group at the telephoto end is set as D23t and the interval between the second lens group and the third lens group at the wide-angle end is set as D23w, the zoom lens of the above aspect preferably satisfies the conditional expression (1) represented below:

[0009] D23t / D23w < 1 (1).

[0010] When the combined lateral magnification of the second lens group and the third lens group at the telephoto end is set to 23t and the combined lateral magnification of the second lens group and the third lens group at the wide-angle end is set to β23w, the zoom lens of the above-described method preferably satisfies the conditional expression (2) represented below:

[0011] 1.4 < β23t / β23w < 3 (2).

[0012] When the focal length of the fourth lens group is set to fG4 and the focal length of the zoom lens at the wide-angle end is set to fw, the zoom lens of the above-described method preferably satisfies the conditional expression (3) represented below:

[0013] -15 < fG4 / fw < -1 (3).

[0014] When the focal length of the first A partial group is set to fG1A and the focal length of the first C partial group is set to fG1C, the zoom lens of the above-described method preferably satisfies the conditional expression (4) represented below:

[0015] -0.5 < fG1A / fG1C < 0.5 (4).

[0016] When the focal length of the first A partial group is set to fG1A and the focal length of the first B partial group is set to fG1B, the zoom lens of the above-described method preferably satisfies the conditional expression (5) represented below:

[0017] 0 < |fG1A / fG1B| < 0.3 (5).

[0018] When the focal length of the first lens group is set to fG1 and the focal length of the zoom lens at the wide-angle end is set to fw, the zoom lens of the above-described method preferably satisfies the conditional expression (6) represented below:

[0019] -4 < fG1 / fw < -1 (6).

[0020] It can be configured such that the first C partial group does not move during focusing.

[0021] In a structure in which the first C partial group includes at least one negative lens, when the average value of the Abbe numbers of all the negative lenses included in the first C partial group based on the d line is set to vave, the zoom lens of the above-described method preferably satisfies the conditional expression (7) represented below:

[0022] vave > 50 (7).

[0023] The zoom lens of the above-described method is preferably telecentric on the reduction side.

[0024] When the focal length of the second lens group is set as fG2 and the focal length of the zoom lens at the wide-angle end is set as fw, the zoom lens of the above-described method preferably satisfies the conditional expression (8) represented below:

[0025] 2 < fG2 / fw < 10 (8).

[0026] When the focal length of the third lens group is set as fG3 and the focal length of the zoom lens at the wide-angle end is set as fw, the zoom lens of the above-described method preferably satisfies the conditional expression (9) represented below:

[0027] 4 < fG3 / fw < 12 (9).

[0028] When the focal length of the final lens group is set as fGE and the focal length of the zoom lens at the wide-angle end is set as fw, the zoom lens of the above-described method preferably satisfies the conditional expression (10) represented below:

[0029] 3 < fGE / fw < 8 (10).

[0030] When the back focal length on the reduction side of the zoom lens in terms of air equivalent distance is set as Bf and the focal length of the zoom lens at the wide-angle end is set as fw, the zoom lens of the above-described method preferably satisfies the conditional expression (11) represented below:

[0031] 2 < Bf / fw (11).

[0032] The intermediate group preferably includes, on the reduction side most adjacent, a cemented lens formed by sequentially cementing a negative lens and a positive lens from the magnification side to the reduction side.

[0033] The first C partial group may be configured to include a negative lens and a positive lens in order from the magnification side to the reduction side.

[0034] Another aspect of the present invention is a projection display device including the zoom lens of the above-described method.

[0035] Another aspect of the present invention is an imaging device including the zoom lens of the above-described method.

[0036] In this specification, "including ~" and "including ~ of" mean that, in addition to the recited components, it may also include: a lens having substantially no optical power; optical components other than lenses such as an aperture, a mask, a filter, a cover glass, a plane mirror, and a prism; and mechanism parts such as a lens flange, a lens barrel, an imaging element, and a shake correction mechanism.

[0037] The "group with positive refractive power" in this specification means that the entire group has positive refractive power. Similarly, the "group with negative refractive power" means that the entire group has negative refractive power. The "lens with positive refractive power" has the same meaning as a "positive lens". The "lens with negative refractive power" has the same meaning as a "negative lens". The "~ lens group" and the "focusing group" in this specification are not limited to structures including multiple lenses, and can also be configured to include only one lens.

[0038] A compound aspherical lens (a lens in which a lens (e.g., a spherical lens) and an aspherical film formed on the spherical lens are integrated and function as one aspherical lens as a whole) is used as one lens and is not regarded as a cemented lens. Unless otherwise specified, the sign of the refractive power related to a lens including an aspherical surface uses the refractive power of the paraxial region. The "focal length" used in the conditional expression is the paraxial focal length. The values used in the conditional expression are values based on the d-line.

[0039] The "d-line", "C-line", and "F-line" described in this specification are bright lines. The wavelength of the d-line is regarded as 587.56 nm (nanometers), the wavelength of the C-line is regarded as 656.27 nm (nanometers), and the wavelength of the F-line is regarded as 486.13 nm (nanometers).

[0040] Advantages of the Invention

[0041] According to the present invention, it is possible to provide a zoom lens, a projection display device including the zoom lens, and an imaging device including the zoom lens. The zoom lens has a wide angle, a high magnification ratio, is compactly configured, has well-suppressed aberration variations during zooming and focusing, and has high optical performance. Description of the Drawings

[0042] Figure 1 The zoom lens corresponding to Embodiment 1 is a cross-sectional view showing the structure of the zoom lens and the light beam according to one embodiment.

[0043] Figure 2 It shows Figure 1 A cross-sectional view of the structure of the zoom lens in each zoom state.

[0044] Figure 3 It is an aberration diagram of the zoom lens of Embodiment 1 in a state where the projection distance is infinite.

[0045] Figure 4 It is an aberration diagram of the zoom lens of Embodiment 1 in a state where the projection distance is 1370 mm (millimeters).

[0046] Figure 5 It is a cross-sectional view showing the structure of the zoom lens of Embodiment 2 and the light beam.

[0047] Figure 6 These are aberration diagrams of the zoom lens of Example 2 in the state where the projection distance is infinite.

[0048] Figure 7 These are aberration diagrams of the zoom lens of Example 2 in the state where the projection distance is 1370 mm (millimeters).

[0049] Figure 8 This is a cross-sectional view showing the structure and light beam of the zoom lens of Example 3.

[0050] Figure 9 These are aberration diagrams of the zoom lens of Example 3 in the state where the projection distance is infinite.

[0051] Figure 10 These are aberration diagrams of the zoom lens of Example 3 in the state where the projection distance is 1370 mm (millimeters).

[0052] Figure 11 This is a cross-sectional view showing the structure and light beam of the zoom lens of Example 4.

[0053] Figure 12 These are aberration diagrams of the zoom lens of Example 4 in the state where the projection distance is infinite.

[0054] Figure 13 These are aberration diagrams of the zoom lens of Example 4 in the state where the projection distance is 1370 mm (millimeters).

[0055] Figure 14 This is a cross-sectional view showing the structure and light beam of the zoom lens of Example 5.

[0056] Figure 15 These are aberration diagrams of the zoom lens of Example 5 in the state where the projection distance is infinite.

[0057] Figure 16 These are aberration diagrams of the zoom lens of Example 5 in the state where the projection distance is 1370 mm (millimeters).

[0058] Figure 17 This is a schematic structural diagram of a projection display device according to an embodiment.

[0059] Figure 18 This is a schematic structural diagram of a projection display device according to another embodiment.

[0060] Figure 19 This is a schematic structural diagram of a projection display device according to yet another embodiment.

[0061] Figure 20 This is a perspective view of the front side of a camera device according to an embodiment.

[0062] Figure 21 is Figure 20 A perspective view of the back side of the imaging device shown in

[0063] Symbol Explanation

[0064] 10 - Zoom lens, 11a~11c - Transmissive display element, 12 - Dichroic mirror, 13 - Dichroic mirror, 14 - Cross dichroic prism, 15 - Light source, 16a~16c - Condensing lens, 18a~18c - Total reflection mirror, 21a~21c - DMD element, 24a~24c - TIR prism, 25 - Polarizing beam splitter prism, 31a~31c - Reflective display element, 32 - Dichroic mirror, 33 - Dichroic mirror, 34 - Cross dichroic prism, 35a~35c - Polarizing beam splitter prism, 38 - Total reflection mirror, 41 - Camera body, 42 - Shutter button, 43 - Power button, 44 - Operation unit, 45 - Operation unit, 46 - Display unit, 47 - Bayonet mount, 48 - Interchangeable lens, 49 - Zoom lens, 50 - Imaging element, 100 - Projection display device, 105 - Screen, 200 - Projection display device, 205 - Screen, 210 - Zoom lens, 215 - Light source, 300 - Projection display device, 305 - Screen, 310 - Zoom lens, 315 - Light source, 400 - Camera, D23t - Spacing, D23w - Spacing, G1 - First lens group, G1A - First A partial group, G1B - First B partial group, G1C - First C partial group, G2 - Second lens group, G3 - Third lens group, G4 - Fourth lens group, G5 - Fifth lens group, G6 - Sixth lens group, G7 - Seventh lens group, GE - Final lens group, GM - Intermediate group, K0 - On-axis beam, K1 - Beam with maximum half-angle of view, L11~L71 - Lenses, PP - Optical component, Sim - Image display surface, Z - Optical axis. Detailed Embodiments

[0065] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0066] In Figure 1 a cross-sectional view of the structure of a zoom lens and a beam, as well as a movement locus, according to an embodiment of the present invention are shown. In Figure 1 as the beam, the on-axis beam K0 and the beam K1 with the maximum half-angle of view are shown. And, in Figure 2 a cross-sectional view of the structure in each zoom state of the Figure 1 zoom lens is shown. In Figure 2 the wide-angle end state is shown in the upper row marked with "WIDE", the intermediate focal length state is shown in the middle row marked with "MIDDLE", and the telephoto end state is shown in the lower row marked with "TELE". Figure 1 andFigure 2 The structural example shown corresponds to Embodiment 1 described later. In Figure 1 and Figure 2 , the left side is set as the magnification side and the right side is set as the reduction side. Hereinafter, the description will be mainly made with reference to Figure 1 .

[0067] The zoom lens of the present invention can be mounted on a projection display device as a projection optical system for forming an image projected onto a screen, and can also be mounted on an imaging device as an imaging optical system for forming an image of an object. Hereinafter, a case where the zoom lens is used as a projection optical system will be assumed for description. And hereinafter, in order to avoid a long description, the "zoom lens of the present invention" is sometimes simply referred to as the "zoom lens".

[0068] In Figure 1 , an example is shown in which it is assumed that the zoom lens is mounted on a projection display device and an optical component PP and an image display surface Sim of a light valve are arranged on the reduction side of the zoom lens. The optical component PP is a component conceived as a filter, a cover glass, a color synthesis prism, etc. The optical component PP is a component having no optical power, and the structure in which the optical component PP is omitted may also be used. The light valve outputs an optical image, and this optical image is displayed on the image display surface Sim in the form of an image.

[0069] In the projection display device, a light beam given image information on the image display surface Sim is incident on the zoom lens via the optical component PP and projected onto a screen (not shown) by the zoom lens. In this case, the image display surface Sim corresponds to the reduction-side conjugate surface, and the screen corresponds to the magnification-side conjugate surface. In addition, in this specification, the "screen" means an object onto which the projected image formed by the zoom lens is projected. As the screen, in addition to a dedicated screen, it may also be a wall surface, a floor surface, a ceiling, an outer wall of a building, etc. of a room.

[0070] In addition, in the description of this specification, the "magnification side" means the screen side on the optical path, and the "reduction side" means the image display surface Sim side on the optical path. In this specification, the "magnification side" and the "reduction side" are defined along the optical path, and the same applies to the case of a zoom lens having a bent optical path. "The one closest to the magnification side" means the one closest to the magnification side in the arrangement order on the optical path, and does not mean the one closest to the screen in terms of distance. Hereinafter, in order to avoid the description from becoming long, "in order along the optical path from the magnification side to the reduction side" is described as "from the magnification side to the reduction side in order".

[0071] The zoom lens of the present invention sequentially includes a first lens group G1 having a negative optical power, a second lens group G2 having a positive optical power, a third lens group G3 having a positive optical power, a fourth lens group G4 having a negative optical power, an intermediate group GM including one or more lens groups, and a final lens group GE having a positive optical power from the magnifying side to the reducing side. By setting the lens group closest to the magnifying side to a group with negative optical power, miniaturization can be achieved by reducing the diameter of the lens closest to the magnifying side and ensuring a sufficient back focal length. The second lens group G2 and the third lens group G3 having positive optical powers can play a major role in zooming. The fourth lens group G4 and the intermediate group GM can perform image plane correction. In particular, by setting the fourth lens group G4 to a group with negative optical power, the aberration from the wide-angle end to the telephoto end caused by the increase in the movement amount of the lens group accompanying high magnification ratio can be corrected. By setting the intermediate group GM to a structure that can be multi-grouped, high magnification ratio and high performance are facilitated. The final lens group GE can perform an imaging function and the telecentricity on the reducing side by having a positive optical power.

[0072] During zooming, the first lens group G1 and the final lens group GE do not move, and all the lens groups within the second lens group G2, the third lens group G3, the fourth lens group G4, and the intermediate group GM change the interval in the optical axis direction between the adjacent lens groups and move along the optical axis Z. In addition, the "during zooming ~ does not move" mentioned here means being fixed to the conjugate plane on the reducing side during zooming. By keeping the first lens group G1 closest to the magnifying side stationary during zooming, it is beneficial to suppressing the change in the center of gravity position during zooming. By keeping the final lens group GE stationary during zooming, it is easy to ensure the imaging function and the telecentricity on the reducing side.

[0073] In addition, in this specification, a group whose interval in the optical axis direction between the adjacent groups changes during zooming is regarded as one lens group. During zooming, the interval between the adjacent lenses within one lens group does not change. That is, a "lens group" is a component of the zoom lens and is a part including at least one lens separated by an air interval that changes during zooming. During zooming, each lens group moves or is fixed unitarily. In addition, a "lens group" may include components other than lenses having no optical power, such as an aperture, a mask, a filter, a cover glass, a plane mirror, etc.

[0074] As an example, Figure 1 the zoom lens sequentially includes a first lens group G1, a second lens group G2, a third lens group G3, a fourth lens group G4, a fifth lens group G5, and a sixth lens group G6 from the magnifying side to the reducing side. In Figure 1 the example, the intermediate group GM includes the fifth lens group G5, and the final lens group GE includes the sixth lens group G6. In Figure 1In the figure, below each lens group that moves during zooming, schematic movement trajectories of the lens groups during zooming from the wide-angle end to the telephoto end are shown by solid arrows.

[0075] As an example, Figure 1 each group of [lens group name] is configured as follows. The first lens group G1 includes six lenses L11 to L16 in order from the magnifying side to the reducing side. The second lens group G2 includes one lens L21. The third lens group G3 includes one lens L31. The fourth lens group G4 includes one lens L41. The fifth lens group G5 includes six lenses L51 to L56 in order from the magnifying side to the reducing side. The sixth lens group G6 includes one lens L61.

[0076] In the zoom lens of the present invention, the interval between the second lens group G2 and the third lens group G3 at the telephoto end is configured to be shorter than the interval between the second lens group G2 and the third lens group G3 at the wide-angle end. By configuring the interval between the second lens group G2 and the third lens group G3 that bears the main zooming function as described above, it is beneficial to suppress the increase in the overall lens length, and while suppressing the increase in the diameter of the lenses of the lens group that moves during zooming, ensure the zoom ratio and correct the spherical aberration on the telephoto side.

[0077] Moreover, in the zoom lens of the present invention, the first lens group G1 includes a first partial group G1A, a first partial group G1B, and a first partial group G1C having negative optical power in order from the magnifying side to the reducing side. During focusing, the interval between the first partial group G1A and the first partial group G1B changes, and the interval between the first partial group G1B and the first partial group G1C changes. That is, in the present invention, focusing is performed by moving the partial groups within the first lens group G1 along the optical axis Z. Hereinafter, the group that moves during focusing is referred to as the focusing group. By arranging the focusing group in the first lens group G1 that does not move during zooming, an operation of separating zooming and focusing can be performed. Also, in a projection optical system, performance changes during projection distance variation with wide-angleization tend to be a problem. However, as in the present invention, by changing the intervals on the magnifying side and the reducing side adjacent to the first partial group G1B for focusing, it is beneficial to suppress the performance changes during the above-mentioned projection distance variation. In addition, in this specification, the "projection distance" means the distance on the optical axis from the magnifying-side conjugate plane to the lens surface closest to the magnifying side of the zoom lens.

[0078] In the present invention, during focusing, only the 1B partial group G1B can be moved, or the 1A partial group G1A and the 1B partial group G1B can be moved while changing their mutual interval, or the 1B partial group G1B and the 1C partial group G1C can be moved while changing their mutual interval, or the 1A partial group G1A, the 1B partial group G1B, and the 1C partial group G1C can be moved while changing the intervals with adjacent groups. The 1B partial group G1B can be a group with positive optical power or a group with negative optical power. The 1C partial group G1C can be a group with positive optical power or a group with negative optical power.

[0079] As an example, in Figure 1 the zoom lens, the 1A partial group G1A includes lenses L11 to L13, the 1B partial group G1B includes lens L14, and the 1C partial group G1C includes lenses L15 to L16. In Figure 1 the example, during focusing, only the 1B partial group G1B moves, and the 1A partial group G1A and the 1C partial group G1C do not move. That is, in Figure 1 the example, the focusing group includes the 1B partial group G1B. In Figure 1 , two arrows in the left - right direction are marked below the focusing group. During focusing, the 1C partial group G1C does not move, whereby the structure can be simplified, and thus it can contribute to cost reduction. During focusing, the 1A partial group G1A does not move, whereby the structure can be simplified, and thus it can contribute to cost reduction. Moreover, by keeping the 1A partial group G1A with a large lens diameter stationary, it is beneficial to reduce the load on the drive system.

[0080] The intermediate group GM preferably includes a cemented lens formed by sequentially cementing a negative lens and a positive lens from the magnification side to the reduction side on the most reduction - side. In this case, it is beneficial to correct the longitudinal chromatic aberration, especially beneficial to correct the longitudinal chromatic aberration during zooming.

[0081] The zoom lens of the present invention preferably has a telecentric reduction side. For example, in a projection - type display device for projecting high - definition images, a so - called three - panel method in which image display elements corresponding to the wavelengths of blue, green, and red are provided is usually adopted. To cope with this method, it is preferably configured to be telecentric on the reduction side. Strictly speaking, in an optical system configured to be telecentric on the reduction side, the chief ray from the surface of the optical system closest to the reduction side toward the reduction - side conjugate plane is parallel to the optical axis Z.

[0082] However, the "reduction-side telecentricity" in the technology of the present invention is not limited to the case where the angle of the chief ray with respect to the optical axis Z is 0 degrees, including the errors actually allowed in the technical field to which the technology of the present invention belongs. For example, the error can be set such that the angle of the chief ray with respect to the optical axis Z is in the range of -3 degrees or more and +3 degrees or less. In addition, in a system that does not include an aperture stop, when observing the light beam in the direction from the magnification side to the reduction side, the bisector of the upper maximum ray and the lower maximum ray in the cross-section of the light beam converging to the point on the reduction-side conjugate plane can be used instead of the chief ray to determine the telecentricity.

[0083] Next, a preferred structure related to the conditional expressions of the zoom lens of the present invention will be described. In addition, in the following description related to the conditional expressions, in order to avoid a long description, the same notations are used for the parts with the same definitions, and the repeated description of the notations is omitted.

[0084] The zoom lens preferably satisfies the following conditional expression (1). Here, the interval between the second lens group G2 and the third lens group G3 at the telephoto end is set as D23t. The interval between the second lens group G2 and the third lens group G3 at the wide-angle end is set as D23w. As an example, in Figure 2 the above intervals D23t and D23w are shown. If a high magnification ratio is to be achieved, it is likely to cause an increase in the overall lens length and an increase in the diameter of the lenses of the lens group that moves during zooming. However, by preventing the corresponding value of the conditional expression (1) from becoming above the upper limit value, it is beneficial to ensure a high magnification ratio without causing an increase in the overall lens length and an increase in the diameter of the lenses of the lens group that moves during zooming. And if an increase in the overall lens length is to be suppressed, it is likely to cause the inconvenience of being difficult to correct the good spherical aberration on the telephoto side, but by preventing the corresponding value of the conditional expression (1) from becoming above the upper limit value, the above inconvenience can also be avoided.

[0085] D23t / D23w < 1 (1)

[0086] The zoom lens preferably satisfies the following conditional expression (1-1). By preventing the corresponding value of the conditional expression (1-1) from becoming below the lower limit value, the third lens group G3 can be prevented from being too close to the second lens group G2 at the telephoto end. Thereby, it is easy to maintain the mechanical holding structure in which the lenses do not contact each other, or it is easy to maintain the interval of the grooves of the cams of the lens group that moves in a suspended manner.

[0087] 0.05 < D23t / D23w < 1 (1-1)

[0088] In order to obtain better characteristics, the upper limit values of the conditional expression (1) and the conditional expression (1-1) are preferably set to 0.9.

[0089] The zoom lens preferably satisfies the following conditional expression (2). Here, the combined lateral magnification of the second lens group G2 and the third lens group G3 at the telephoto end is set as β23t. The combined lateral magnification of the second lens group G2 and the third lens group G3 at the wide-angle end is set as β23w. In addition, β23t and β23w are set as values in a state where the projection distance is infinite. By preventing the corresponding value of the conditional expression (2) from becoming below the lower limit value, it is beneficial to ensure the zoom ratio. More specifically, by preventing the corresponding value of the conditional expression (2) from becoming below the lower limit value, it is beneficial to ensure the zoom ratio while suppressing an increase in the overall lens length. The conditional expression (2) represents the magnitude of the zooming action of the second lens group G2 and the third lens group G3. If the zooming action of the second lens group G2 and the third lens group G3 becomes too large, the lens group on the reduction side relative to the third lens group G3 bears a large zooming action to offset a part of this zooming action. In this case, there is an inconvenience that it is difficult to perform aberration correction accompanying zooming. By preventing the corresponding value of the conditional expression (2) from becoming above the upper limit value, the zooming action of the second lens group G2 and the third lens group G3 does not become too large, so the above inconvenience can be avoided, and thus it is beneficial to aberration correction.

[0090] 1.4 < β23t / β23w < 3 (2)

[0091] In order to obtain better characteristics, the lower limit value of the conditional expression (2) is more preferably set to 1.5. And, in order to obtain better characteristics, the upper limit value of the conditional expression (2) is more preferably set to 2.5.

[0092] When the focal length of the fourth lens group G4 is set as fG4 and the focal length of the zoom lens at the wide-angle end is set as fw, the zoom lens preferably satisfies the following conditional expression (3). In addition, fw is set as a value in a state where the projection distance is infinite. By preventing the corresponding value of the conditional expression (3) from becoming below the lower limit value, the negative optical power of the fourth lens group G4 does not become too weak, so the aberration correction at the wide-angle end and the telephoto end can have a greater effect, and it is easy to ensure a sufficiently long back focal length. By preventing the corresponding value of the conditional expression (3) from becoming above the upper limit value, the negative optical power of the fourth lens group G4 does not become too strong, so it is beneficial to correct spherical aberration.

[0093] -15 < fG4 / fw < -1 (3)

[0094] In order to obtain better characteristics, the lower limit value of the conditional expression (3) is more preferably set to -12. And, in order to obtain better characteristics, the upper limit value of the conditional expression (3) is more preferably set to -1.5.

[0095] When the focal length of the first group G1A of the first part is set to fG1A and the focal length of the first group G1C of the first part is set to fG1C, the zoom lens preferably satisfies the following conditional expression (4). By preventing the corresponding value of the conditional expression (4) from becoming less than the lower limit value, the positive refractive power of the first group G1C with respect to the first group G1A does not become too strong. Therefore, it is easy to maintain the balance of the refractive power within the first lens group G1 well, and thus it is beneficial to suppress the performance change accompanying the change in the projection distance. By preventing the corresponding value of the conditional expression (4) from becoming greater than the upper limit value, the negative refractive power of the first group G1C with respect to the first group G1A does not become too strong. Therefore, it does not cause the first group G1A to have a larger diameter and can maintain the required negative refractive power of the first lens group G1. Thus, it is beneficial to miniaturization.

[0096] -0.5 < fG1A / fG1C < 0.5 (4)

[0097] To obtain better characteristics, the lower limit value of the conditional expression (4) is more preferably set to -0.28. And, to obtain better characteristics, the upper limit value of the conditional expression (4) is more preferably set to 0.22.

[0098] When the focal length of the first group G1B of the first part is set to fG1B, the zoom lens preferably satisfies the following conditional expression (5). Regarding the lower limit of the conditional expression (5), since |fG1A / fG1B| is an absolute value, it becomes 0 < |fG1A / fG1B|. By preventing the corresponding value of the conditional expression (5) from becoming greater than the upper limit value, the refractive power of the first group G1B with respect to the first group G1A does not become too strong. Therefore, it is beneficial to suppress the variation of each aberration accompanying the change in the projection distance, and particularly beneficial to suppress the variation of field curvature. Thus, it is easy to balance wide-angle and high magnification ratio.

[0099] 0 < |fG1A / fG1B| < 0.3 (5)

[0100] To obtain better characteristics, the upper limit value of the conditional expression (5) is more preferably set to 0.1.

[0101] When the focal length of the first lens group G1 is set to fG1, the zoom lens preferably satisfies the following conditional expression (6). In addition, fG1 is set to the value in the state where the projection distance is infinite. By preventing the corresponding value of the conditional expression (6) from becoming less than the lower limit value, the refractive power of the first lens group G1 does not become too weak. Therefore, it is easy to ensure the desired back focal length and can suppress the increase in the total lens length. By preventing the corresponding value of the conditional expression (6) from becoming greater than the upper limit value, the refractive power of the first lens group G1 does not become too strong. Therefore, it is beneficial to correct the distortion aberration and field curvature that are problems in wide-angle.

[0102] -4 < fG1 / fw < -1 (6)

[0103] In order to obtain better characteristics, the lower limit value of conditional expression (6) is more preferably set to -3. Also, in order to obtain better characteristics, the upper limit value of conditional expression (6) is more preferably set to -1.5.

[0104] The first C-part group G1C can be configured to include at least one negative lens. In the structure where the first C-part group G1C includes at least one negative lens, the zoom lens preferably satisfies the following conditional expression (7). Here, the average value of the Abbe numbers of the d-line reference of all the negative lenses included in the first C-part group G1C is set to v ave. By preventing the corresponding value of conditional expression (7) from becoming below the lower limit value, it is beneficial for correcting the longitudinal chromatic aberration that becomes a problem during wide-angle conversion.

[0105] v ave>50 (7)

[0106] Also, the zoom lens preferably satisfies the following conditional expression (7-1). By preventing the corresponding value of conditional expression (7-1) from becoming above the upper limit value, the high cost of the lens can be suppressed, and thus it is beneficial for cost reduction.

[0107] 50<v ave<100 (7-1)

[0108] In order to obtain better characteristics, the lower limit value of conditional expression (7) and conditional expression (7-1) is preferably set to 65.

[0109] When the focal length of the second lens group G2 is set to fG2, the zoom lens preferably satisfies the following conditional expression (8). By preventing the corresponding value of conditional expression (8) from becoming below the lower limit value, the optical power of the second lens group G2 does not become too strong, and thus it is beneficial for aberration correction during zooming. By preventing the corresponding value of conditional expression (8) from becoming above the upper limit value, the movement amount of the second lens group G2 during zooming can be suppressed, and thus it is beneficial for miniaturization.

[0110] 2<fG2 / fw<10 (8)

[0111] In order to obtain better characteristics, the lower limit value of conditional expression (8) is more preferably set to 4. Also, in order to obtain better characteristics, the upper limit value of conditional expression (8) is more preferably set to 8.

[0112] When the focal length of the third lens group G3 is set to fG3, the zoom lens preferably satisfies the following conditional expression (9). By preventing the corresponding value of conditional expression (9) from becoming below the lower limit value, the optical power of the third lens group G3 does not become too strong, and thus it is beneficial for aberration correction during zooming. By preventing the corresponding value of conditional expression (9) from becoming above the upper limit value, the movement amount of the third lens group G3 during zooming can be suppressed, and thus it is beneficial for miniaturization.

[0113] 4 < fG3 / fw < 12 (9)

[0114] In order to obtain better characteristics, the lower limit value of conditional expression (9) is more preferably set to 5. Also, in order to obtain better characteristics, the upper limit value of conditional expression (9) is more preferably set to 9.

[0115] When the focal length of the final lens group GE is set to fGE, the zoom lens preferably satisfies the following conditional expression (10). By preventing the corresponding value of conditional expression (10) from becoming below the lower limit value, the optical power of the final lens group GE does not become too strong, so it is beneficial to balance maintaining telecentricity and ensuring an appropriate back focal length. By preventing the corresponding value of conditional expression (10) from becoming above the upper limit value, the back focal length does not become too long, so it is beneficial to miniaturize the entire lens system including the back focal length.

[0116] 3 < fGE / fw < 8 (10)

[0117] In order to obtain better characteristics, the lower limit value of conditional expression (10) is more preferably set to 4. Also, in order to obtain better characteristics, the upper limit value of conditional expression (10) is more preferably set to 7.

[0118] When the back focal length on the reduction side of the zoom lens in terms of air equivalent distance is set to Bf, the zoom lens preferably satisfies the following conditional expression (11). In addition, Bf is set to the value in the state where the projection distance is infinite. By preventing the corresponding value of conditional expression (11) from becoming below the lower limit value, the back focal length does not become too short, so it is easy to arrange a color combining prism, etc.

[0119] 2 < Bf / fw (11)

[0120] Also, the zoom lens preferably satisfies the following conditional expression (11-1). By preventing the corresponding value of conditional expression (11-1) from becoming above the upper limit value, it is beneficial to miniaturize the entire lens system including the back focal length.

[0121] 2 < Bf / fw < 8 (11-1)

[0122] In order to obtain better characteristics, the lower limit values of conditional expression (11) and conditional expression (11-1) are preferably set to 2.5.

[0123] In addition, Figure 1 The example shown is just one example, and various modifications can be made without departing from the gist of the technology of the present invention.

[0124] For example, the first part group G1A can be configured to include three negative lenses. The first part group G1B can be configured to include one lens or can be configured to include two lenses. When the first part group G1B includes one lens, the lens can be a positive lens or a negative lens. When the first part group G1B includes two lenses, for example, it can be configured to include a negative lens and a positive lens. The first part group G1C can be configured to include a negative lens and a positive lens in sequence from the magnifying side to the reducing side. When the first part group G1C is configured in this way, it is beneficial to correct the longitudinal chromatic aberration.

[0125] The focusing group can be configured to include one lens or can be configured to include two lenses. By minimizing the number of lens elements that make up the focusing group, it is beneficial to miniaturize and lighten the focusing group.

[0126] The second lens group G2 can be configured to include one positive lens. The third lens group G3 can be configured to include one positive lens. The fourth lens group G4 can be configured to include one lens, can be configured to include two lenses, or can also be configured to include four lenses.

[0127] The intermediate group GM can be configured to include one lens group or can be configured to include two lens groups.

[0128] The final lens group GE can be configured to include one positive lens.

[0129] In order to absorb the tilt error and / or position error of the mounting bayonet of the zoom lens and the projection display device, etc., it can be configured to be able to move the lens closer to the magnifying side than the focusing group as a post-adjustment group. For example, in Figure 1 the example, the lens L14 is the focusing group, but it can also be configured such that the lenses L11 - L13 are movable as the post-adjustment group.

[0130] The above-mentioned preferred structures and achievable structures can be arbitrarily combined within the non-conflicting range, and it is preferably selectively adopted appropriately according to the required specifications.

[0131] As an example, a preferred embodiment of the zoom lens of the present invention is as follows: It sequentially includes a first lens group G1 having a negative optical power, a second lens group G2 having a positive optical power, a third lens group G3 having a positive optical power, a fourth lens group G4 having a negative optical power, an intermediate group GM including one or more lens groups, and a final lens group GE having a positive optical power from the telephoto side to the wide-angle side. Among them, the first lens group G1 sequentially includes a first partial group G1A having a negative optical power, a first partial group G1B having a positive optical power, and a first partial group G1C having a positive optical power from the telephoto side to the wide-angle side. During focusing, the interval between the first partial group G1A and the first partial group G1B changes, and the interval between the first partial group G1B and the first partial group G1C changes. During zooming, the first lens group G1 and the final lens group GE do not move, and all the lens groups in the second lens group G2, the third lens group G3, the fourth lens group G4, and the intermediate group GM change the interval in the optical axis direction between adjacent lens groups and move along the optical axis Z. The interval between the second lens group G2 and the third lens group G3 at the telephoto end is shorter than the interval between the second lens group G2 and the third lens group G3 at the wide-angle end.

[0132] Next, embodiments of the zoom lens of the present invention will be described with reference to the accompanying drawings. In addition, the reference signs attached to the groups and lenses in the cross-sectional views of the respective embodiments are used independently for each embodiment to avoid complication of the description and the drawings due to an increase in the number of digits of the reference signs. Therefore, even if the same reference sign is attached in the drawings of different embodiments, it is not necessarily the same structure.

[0133] [Embodiment 1]

[0134] The structure of the zoom lens and the cross-section of the light beam in Embodiment 1 in a state where the projection distance is infinite are shown in Figure 1 , and the illustration method and structure are as described above, so a part of the repeated description is omitted here. The zoom lens of Embodiment 1 sequentially includes a first lens group G1, a second lens group G2, a third lens group G3, a fourth lens group G4, a fifth lens group G5, and a sixth lens group G6 from the telephoto side to the wide-angle side. The first lens group G1 sequentially includes a first partial group G1A having a negative optical power, a first partial group G1B having a positive optical power, and a first partial group G1C having a positive optical power from the telephoto side to the wide-angle side.

[0135] Regarding the zoom lens of Embodiment 1, the basic lens data is shown in Table 1, the specifications and the variable surface intervals during zooming are shown in Table 2, the aspherical coefficients are shown in Table 3, and the variable surface intervals during focusing are shown in Table 4.

[0136] The basic lens data table is described as follows. In the "Sn" column, the surface numbers are shown when the surface closest to the magnification side is defined as the first surface and the numbers increase sequentially towards the reduction side. In the "R" column, the curvature radii of the respective surfaces are shown. In the "D" column, the axial surface intervals between each surface and the surface adjacent to its reduction side are shown. In the "Nd" column, the refractive indices of the respective components with respect to the d-line are shown. In the "vd" column, the Abbe numbers of the respective components based on the d-line are shown.

[0137] In the basic lens data table, the sign of the curvature radius of the surface with the convex shape facing the magnification side is set to positive, and the sign of the curvature radius of the surface with the convex shape facing the reduction side is set to negative. The value in the bottom row of the D column in the table is the interval between the surface closest to the reduction side in the table and the image display surface Sim. In the basic lens data table, the notation DD[] is used for the variable surface interval during zooming, and the surface number on the magnification side of this interval is marked in [] and entered in the D column. The data for the state where the projection distance is infinite is shown in Table 1.

[0138] In Table 2, the zoom ratio Zr, focal length f, F-number FNo., and maximum full viewing angle 2ω are shown based on the d-line. The [°] in the 2ω column indicates that the unit is degrees. In Table 2, the values at the wide-angle end are shown in the "WIDE" column, the values in the state of the intermediate focal length are shown in the "MIDDLE" column, and the values at the telephoto end are shown in the "TELE" column.

[0139] In the basic lens data, an asterisk (*) is marked on the surface numbers of the aspherical surfaces, and the value of the paraxial curvature radius is recorded in the curvature radius column of the aspherical surfaces. In Table 3, the surface numbers of the aspherical surfaces are shown in the Sn row, and the numerical values of the aspherical coefficients for the respective aspherical surfaces are shown in the KA and Am rows. Additionally, m in Am is an integer of 3 or more and varies depending on the surface. For example, in the first surface of Example 1, m = 3, 4, 5,..., 16. The "E±n" (n: integer) of the numerical values of the aspherical coefficients in Table 3 represents "×10 +n ". KA and Am are the aspherical coefficients in the aspherical formula represented by the following formula.

[0140] Zd = C×h 2 / {1+(1 - KA×C 2 ×h 2 ) 1 / 2}+∑Am×h m

[0141] Among them,

[0142] Zd: Aspherical depth (the length of the perpendicular line dropped from the point on the aspherical surface at height h to the plane tangent to the aspherical vertex and perpendicular to the optical axis Z)

[0143] h: Height (the distance from the optical axis Z to the lens surface)

[0144] C: Reciprocal of the paraxial radius of curvature

[0145] KA, Am: Aspherical coefficients

[0146] The ∑ in the aspherical formula represents the sum related to m.

[0147] Table 4 shows the intervals between the 1A partial group G1A and the 1B partial group G1B, and between the 1B partial group G1B and the 1C partial group G1C, in each state where the projection distance is infinite, 1370 mm (millimeters), and 1000 mm (millimeters).

[0148] In the data of each table, degrees are used as the unit of angle and millimeters as the unit of length. However, since the optical system can be used with magnification or reduction ratios, other appropriate units can also be used. Also, in each of the following tables, values rounded to a predetermined number of digits are recorded.

[0149] [Table 1]

[0150] Example 1

[0151] Sn R D Nd v d *1 -71.4278 5.4151 1.53638 56.09 *2 -923.9705 9.9413 3 56.4401 1.4505 1.60311 60.64 4 22.1826 13.5732 5 -47.5683 1.7402 1.84666 23.78 6 916.7287 6.2846 *7 -49.2875 5.8009 1.53638 56.09 *8 -49.0193 7.5758 9 -52.4507 1.1006 1.49700 81.61 10 65.4053 1.4354 11 168.8137 4.8835 1.80610 33.27 12 -65.3344 DD

[12] 13 46.9335 4.2186 1.83400 37.21 14 183.4195 DD

[14] 15 49.7948 4.8214 1.48749 70.44 16 -364.3234 DD

[16] *17 -44.8480 1.5710 1.58313 59.46 *18 45.8476 DD

[18] 19 46.8708 5.4996 1.83481 42.74 20 25.7646 0.1504 21 26.8733 10.8263 1.51680 64.20 22 -17.3057 0.9000 1.90366 31.31 23 -39.2550 1.6835 24 57.3118 8.9533 1.49700 81.61 25 -36.5941 0.1591 26 ∞ 0.9998 1.87070 40.73 27 28.7934 7.7694 1.49700 81.61 28 -106.5138 DD

[28] 29 57.5686 4.6451 1.72825 28.46 30 -218.4905 14.5650 31 ∞ 31.4200 1.51680 64.20 32 ∞ 0.2143

[0152] [Table 2]

[0153] Example 1

[0154] WIDE MIDDLE TELE Zr 1.0 1.3 1.7 f 11.73 15.01 19.94 FNo. 1.71 1.86 2.07 2ω[°] 90.6 76.4 61.4 DD

[12] 26.24 11.98 0.57 DD

[14] 27.69 21.09 4.20 DD

[16] 4.68 12.19 22.82 DD

[18] 3.47 5.12 7.52 DD

[28] 0.60 12.30 27.55

[0155] [Table 3]

[0156] Example 1

[0157] Sn 1 2 7 8 KA 6.4936443E-01 -1.0000008E+01 1.0000000E+00 1.0000000E+00 A3 -1.5164578E-18 1.7789954E-17 3.5122285E-20 5.4851429E-21 A4 4.2563804E-05 5.5332947E-05 1.0312788E-05 6.4363813E-06 A5 -1.0595712E-06 -5.8357750E-06 1.2457026E-06 7.5634352E-07 A6 3.1937717E-08 7.8041924E-07 -2.5539995E-07 -8.9865873E-08 A7 -6.7450314E-09 -6.7732669E-08 1.3609062E-08 -2.2930151E-09 A8 3.9807796E-10 3.1131104E-09 7.7788648E-10 6.1039834E-10 A9 -5.1422460E-12 -6.4017144E-11 -8.9336591E-11 1.8522457E-11 A10 -2.5719449E-13 -2.0394022E-13 -1.1126640E-12 -3.2109249E-12 A11 7.9429876E-15 3.1564882E-14 2.7712247E-13 -1.3328633E-13 A12 5.2477748E-17 6.9827229E-17 -5.0612815E-16 1.3210294E-14 A13 -4.4629691E-18 -3.4427944E-17 -5.3158776E-16 3.3406970E-16 A14 2.9517711E-20 6.9501329E-19 8.5519986E-18 -2.8155434E-17 A15 7.7752829E-22 3.6019573E-21 4.4837558E-19 -2.8443779E-19 A16 -9.3485027E-24 -1.6976244E-22 -1.3337635E-20 2.2726500E-20

[0158] Sn 17 18 KA 1.0000000E+00 1.0000000E+00 A3 6.4140674E-22 -2.7545960E-21 A4 -6.2430471E-06 -1.1370074E-05 A5 1.3185884E-07 5.3166408E-07 A6 6.1830659E-08 3.3799198E-08 A7 -3.0679335E-10 -1.5367136E-09 A8 -2.4171478E-10 -1.1824888E-10 A9 -1.7520844E-12 -1.5543570E-12 A10 7.0487774E-13 5.7159599E-13

[0159] [Table 4]

[0160] Example 1

[0161]

[0162] In Figure 3 are shown the aberration diagrams of the zoom lens of Example 1 in the state where the projection distance is infinite. In Figure 3 , in the upper row marked with "WIDE", the aberration diagrams at the wide-angle end are shown, in the middle row marked with "MIDDLE", the aberration diagrams in the middle focal length state are shown, and in the lower row marked with "TELE", the aberration diagrams at the telephoto end are shown. In Figure 3Among them, spherical aberration, astigmatism, distortion aberration, and longitudinal chromatic aberration are shown in order from the left. In the spherical aberration diagram, the aberrations related to the d-line, C-line, and F-line are shown by solid lines, long dashed lines, and short dashed lines, respectively. In the astigmatism diagram, the aberration related to the d-line in the sagittal direction is shown by a solid line, and the aberration related to the d-line in the meridional direction is shown by a short dashed line. In the distortion aberration diagram, the aberration related to the d-line is shown by a solid line. In the longitudinal chromatic aberration diagram, the aberrations related to the C-line and F-line are shown by long dashed lines and short dashed lines, respectively. In the spherical aberration diagram, the value of the F-number is shown after "FNo. =". In the other aberration diagrams, the value of the maximum half field angle is shown after "ω =".

[0163] In Figure 4 the aberration diagrams of the zoom lens of Example 1 in the state where the projection distance is 1370 mm (millimeters) are shown. Figure 4 The illustration method of Figure 3 is the same as

[0164] Regarding the notations, meanings, recording methods, and illustration methods of the respective data related to the above Example 1, unless otherwise specified, they are basically the same in the following examples, and thus the repeated explanations are omitted below.

[0165] [Example 2]

[0166] The cross-sectional views of the structure of the zoom lens of Example 2 and the light beam are shown in Figure 5 . The zoom lens of Example 2 includes, in order from the wide-angle side to the telephoto side, a first lens group G1, a second lens group G2, a third lens group G3, a fourth lens group G4, a fifth lens group G5, and a sixth lens group G6. The intermediate group GM includes the fifth lens group G5, and the final lens group GE includes the sixth lens group G6. During zooming, the first lens group G1 and the sixth lens group G6 remain stationary, and the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 change the intervals in the optical axis direction between adjacent lens groups and move along the optical axis Z.

[0167] The first lens group G1 includes, in order from the wide-angle side to the telephoto side, a first partial group G1A having a negative refractive power, a first partial group G1B having a positive refractive power, and a first partial group G1C having a positive refractive power. The first partial group G1A includes three lenses L11 to L13 in order from the wide-angle side to the telephoto side. The first partial group G1B includes one lens L14. The first partial group G1C includes two lenses L15 to L16 in order from the wide-angle side to the telephoto side. During focusing, only the first partial group G1B moves, and the first partial group G1A and the first partial group G1C remain stationary.

[0168] The second lens group G2 includes one lens, i.e., lens L21. The third lens group G3 includes one lens, i.e., lens L31. The fourth lens group G4 includes four lenses, i.e., lenses L41 to L44 in sequence from the magnification side to the reduction side. The fifth lens group G5 includes three lenses, i.e., lenses L51 to L53 in sequence from the magnification side to the reduction side. The sixth lens group G6 includes one lens, i.e., lens L61.

[0169] For the zoom lens of Embodiment 2, the basic lens data is shown in Table 5, the specifications and variable surface intervals during zooming are shown in Table 6, the aspherical coefficients are shown in Table 7, and the variable surface intervals during focusing are shown in Table 8. And, for the zoom lens of Embodiment 2, the aberration diagrams in the state where the projection distance is infinity are shown in Figure 6 , and the aberration diagrams in the state where the projection distance is 1370 mm (millimeters) are shown in Figure 7 .

[0170] [Table 5]

[0171] Embodiment 2

[0172] Sn R D Nd v d *1 -44.1127 5.4991 1.53638 56.09 *2 -64.6296 3.9005 3 77.1282 1.5000 1.60311 60.64 4 21.5189 13.9735 5 -41.7657 1.1991 1.84666 23.78 6 122.5048 5.1644 *7 -109.9004 5.8731 1.53638 56.09 *8 -93.4962 8.6960 9 -63.3561 1.5987 1.49700 81.61 10 109.3747 1.0430 11 275.0355 6.0090 1.80610 33.27 12 -55.7116 DD

[12] 13 53.5445 4.7987 1.83400 37.21 14 377.2859 DD

[14] 15 43.8801 5.2210 1.48749 70.44 16 -266.0640 DD

[16] *17 -69.1359 1.4991 1.85135 40.10 *18 -2479.7917 7.3427 19 129.3857 1.4377 1.80400 46.53 20 23.2789 0.1710 21 24.5550 9.5156 1.48749 70.44 22 -19.0536 0.0810 23 -18.7295 0.8997 1.83400 37.21 24 -263.1609 DD

[24] 25 66.2413 7.7854 1.43700 95.10 26 -25.3598 0.3442 27 131.4378 0.9991 1.83481 42.74 28 30.8611 8.0423 1.49700 81.61 29 -71.6887 DD

[29] 30 59.3052 4.7269 1.80610 33.27 31 -311.1070 13.5650 32 ∞ 31.4200 1.51680 64.20 33 ∞ 0.21

[0173] [Table 6]

[0174] Embodiment 2

[0175] WIDE MIDDLE TELE Zr 1.0 1.3 1.7 f 11.66 14.93 19.83 FNo. 1.70 1.86 2.07 2ω[°] 91.0 76.8 61.6 DD

[12] 29.38 13.71 0.54 DD

[14] 30.30 29.04 20.72 DD

[16] 2.99 7.28 14.32 DD

[24] 1.01 0.99 0.65 DD

[29] 0.52 13.17 27.97

[0176] [Table 7]

[0177] Embodiment 2

[0178] Sn 1 2 7 8 KA 8.4919573E-01 -1.0000009E+01 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 0.0000000E+00 0.0000000E+00 A4 7.1237305E-05 8.9140188E-05 1.6933706E-05 1.1639079E-05 A5 -2.8778567E-06 -1.2412667E-05 -7.3696276E-07 -6.0830440E-07 A6 3.5804851E-08 1.6759493E-06 -1.5575153E-08 3.8391462E-09 A7 -3.4021450E-09 -1.5821118E-07 4.1613778E-09 2.0577896E-09 A8 3.1383594E-10 8.4597765E-09 2.6605610E-10 2.5582118E-10 A9 -6.9355252E-12 -2.0508492E-10 -5.2870434E-11 -3.7070559E-11 A10 -1.8119567E-13 -9.9703149E-13 6.0364744E-13 -1.2580627E-13 A11 8.0266477E-15 1.2660811E-13 1.6598555E-13 1.2930056E-13 A12 3.7480927E-17 1.5776126E-15 -3.8025704E-15 -1.1467845E-15 A13 -4.1066034E-18 -1.7280766E-16 -2.3508174E-16 -1.9955405E-16 A14 1.4779291E-20 2.3630531E-18 5.5408446E-18 1.9297407E-18 A15 6.8725526E-22 2.1901772E-20 1.2746652E-19 1.1642005E-19 A16 -3.1530942E-24 -5.0892306E-22 -2.3826756E-21 -6.1879690E-22

[0179] Sn 17 18 KA 1.0000000E+00 1.0000000E+00 A4 -3.0220639E-07 6.3010280E-07 A6 1.1204202E-08 1.2064579E-08 A8 -4.8803850E-11 -4.3548715E-11 A10 1.6212684E-13 1.6031782E-13

[0180] [Table 8]

[0181] Embodiment 2

[0182]

[0183] [Embodiment 3]

[0184] The structure and cross-sectional view of the light beam of the zoom lens of Embodiment 3 are shown in Figure 8The zoom lens of Example 3 includes, in order from the wide-angle side to the telephoto side, a first lens group G1, a second lens group G2, a third lens group G3, a fourth lens group G4, a fifth lens group G5, and a sixth lens group G6. The intermediate group GM includes the fifth lens group G5, and the final lens group GE includes the sixth lens group G6. During zooming, the first lens group G1 and the sixth lens group G6 remain stationary, and the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 move along the optical axis Z while changing the interval in the optical axis direction between adjacent lens groups.

[0185] The first lens group G1 includes, in order from the wide-angle side to the telephoto side, a first partial group G1A having a negative optical power, a first partial group G1B having a positive optical power, and a first partial group G1C having a negative optical power. The first partial group G1A includes, in order from the wide-angle side to the telephoto side, three lenses L11 to L13. The first partial group G1B includes, in order from the wide-angle side to the telephoto side, two lenses L14 to L15. The first partial group G1C includes, in order from the wide-angle side to the telephoto side, two lenses L16 to L17. During focusing, only the first partial group G1B moves, and the first partial group G1A and the first partial group G1C remain stationary.

[0186] The second lens group G2 includes one lens L21. The third lens group G3 includes one lens L31. The fourth lens group G4 includes, in order from the wide-angle side to the telephoto side, two lenses L41 to L42. The fifth lens group G5 includes, in order from the wide-angle side to the telephoto side, six lenses L51 to L56. The sixth lens group G6 includes one lens L61.

[0187] Regarding the zoom lens of Example 3, the basic lens data is shown in Table 9, the specifications and the variable surface intervals during zooming are shown in Table 10, the aspherical coefficients are shown in Table 11, and the variable surface intervals during focusing are shown in Table 12. Also, regarding the zoom lens of Example 3, the aberration diagrams in the state where the projection distance is infinity are shown in Figure 9 and the aberration diagrams in the state where the projection distance is 1370 mm (millimeters) are shown in Figure 10 .

[0188] [Table 9]

[0189] Example 3

[0190]

[0191]

[0192] [Table 10]

[0193] Example 3

[0194] WIDE MIDDLE TELE Zr 1.0 1.3 1.7 f 11.72 15.00 19.92 FNo. 1.68 1.83 2.05 2ω[°] 90.8 76.6 61.4 DD

[14] 22.62 9.26 0.60 DD

[16] 27.10 23.08 5.38 DD

[18] 5.13 13.44 21.59 DD

[22] 6.99 3.41 3.92 DD

[32] 0.59 13.23 30.92

[0195] [Table 11]

[0196] Example 3

[0197] Sn 1 2 KA 1.6172379E+00 -1.3000001E+02 A3 0.0000000E+00 0.0000000E+00 A4 3.3046957E-05 1.1112641E-05 A5 -1.3513630E-06 -5.2224010E-06 A6 7.8436830E-08 1.1146086E-06 A7 -5.7578962E-09 -1.0322650E-07 A8 1.7377534E-10 4.7261693E-09 A9 1.4221953E-12 -8.6723949E-11 A10 -1.4725355E-13 -8.8875027E-13 A11 -2.3935708E-16 4.0805455E-14 A12 8.6215082E-17 1.1045789E-15 A13 -1.0174392E-19 -5.7680811E-17 A14 -2.7620222E-20 5.5320996E-19 A15 -4.2255431E-24 5.8132517E-21 A16 4.6652975E-24 -9.5182868E 23

[0198] [Table 12]

[0199] Example 3

[0200]

[0201] [Example 4]

[0202] The structure of the zoom lens and the cross-sectional view of the light beam in Example 4 are shown in Figure 11 . The zoom lens in Example 4 includes, in order from the wide-angle side to the telephoto side, a first lens group G1, a second lens group G2, a third lens group G3, a fourth lens group G4, a fifth lens group G5, a sixth lens group G6, and a seventh lens group G7. The intermediate group GM includes two lens groups, namely, the fifth lens group G5 and the sixth lens group G6. The final lens group GE includes the seventh lens group G7. During zooming, the first lens group G1 and the seventh lens group G7 remain stationary, and the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 move along the optical axis Z while changing the interval in the optical axis direction between adjacent lens groups.

[0203] The first lens group G1 includes, in order from the wide-angle side to the telephoto side, a first partial group G1A with a negative optical power, a first partial group G1B with a positive optical power, and a first partial group G1C with a negative optical power. The first partial group G1A includes three lenses, namely, lenses L11 to L13, in order from the wide-angle side to the telephoto side. The first partial group G1B includes one lens, namely, lens L14. The first partial group G1C includes two lenses, namely, lenses L15 to L16, in order from the wide-angle side to the telephoto side. During focusing, only the first partial group G1B moves, and the first partial group G1A and the first partial group G1C remain stationary.

[0204] The second lens group G2 includes one lens, namely, lens L21. The third lens group G3 includes one lens, namely, lens L31. The fourth lens group G4 includes one lens, namely, lens L41. The fifth lens group G5 includes four lenses, namely, lenses L51 to L54, in order from the wide-angle side to the telephoto side. The sixth lens group G6 includes two lenses, namely, lenses L61 to L62, in order from the wide-angle side to the telephoto side. The seventh lens group G7 includes one lens, namely, lens L71.

[0205] Regarding the zoom lens of Example 4, the basic lens data is shown in Table 13, the specifications and the variable surface intervals during zooming are shown in Table 14, the aspherical coefficients are shown in Table 15, and the variable surface intervals during focusing are shown in Table 16. Moreover, regarding the zoom lens of Example 4, the aberration diagrams in the state where the projection distance is infinite are shown in Figure 12 , and the aberration diagrams in the state where the projection distance is 1370 mm (millimeters) are shown in Figure 13 .

[0206] [Table 13]

[0207] Example 4

[0208] Sn R D Nd v d *1 -27.5118 5.5009 1.53638 56.09 *2 -38.8149 0.8924 3 48.1385 1.5003 1.58913 61.13 4 23.6774 14.6263 5 -55.3552 1.1991 1.84666 23.78 6 114.3906 6.8281 *7 -51.5441 6.0009 1.53638 56.09 *8 -43.7030 7.0323 9 -38.8807 1.5287 1.43700 95.10 10 81.1050 1.4937 11 271.0664 5.4599 1.78880 28.43 12 -70.2805 DD

[12] 13 64.1617 5.1501 1.83481 42.74 14 -634.2089 DD

[14] 15 59.3407 5.5227 1.48749 70.44 16 -186.2354 DD

[16] *17 -62.1519 1.4991 1.85135 40.10 *18 -582.6339 DD

[18] 19 203.0754 0.9991 1.83481 42.74 20 25.8197 12.0190 1.49700 81.61 21 -19.2818 0.9000 1.72916 54.68 22 -239.7621 0.2004 23 98.8785 8.3538 1.49700 81.61 24 -29.6481 DD

[24] 25 130.0450 0.9995 1.83400 37.21 26 40.9841 8.2385 1.43700 95.10 27 -68.2020 DD

[27] 28 52.5840 4.9801 1.74400 44.79 29 ∞ 13.5650 30 ∞ 31.4200 1.51680 64.20 31 ∞ 0.1342

[0209] [Table 14]

[0210] Example 4

[0211] WIDE MIDDLE TELE Zr 1.0 1.3 2.0 f 11.70 15.56 23.40 FNo. 1.65 1.84 2.15 2ω[°] 90.6 74.2 53.6 DD

[12] 32.83 16.30 0.60 DD

[14] 28.15 24.07 4.29 DD

[16] 3.33 9.84 22.29 DD

[18] 10.97 7.98 8.35 DD

[24] 0.50 7.39 0.50 DD

[27] 0.84 11.04 40.59

[0212] [Table 15]

[0213] Example 4

[0214] Sn 1 2 7 8 KA -1.4025467E+00 -1.0000000E+01 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 0.0000000E+00 0.0000000E+00 A4 7.7917736E-05 7.3160795E-05 1.5641909E-05 1.2704216E-05 A5 -1.7883362E-06 -7.5064124E-06 1.0435449E-06 -7.2236730E-07 A6 -1.1122274E-07 9.9152606E-07 -1.8504690E-07 1.2274484E-07 A7 1.0703194E-09 -8.8695294E-08 1.0457533E-08 -8.3900249E-09 A8 3.9050085E-10 4.0894824E-09 2.3516457E-10 -2.3373811E-10 A9 -1.3259936E-11 -7.6501242E-11 -6.1195744E-11 5.4902844E-11 A10 -1.6500121E-13 -5.7199142E-13 1.4801715E-12 -7.3016376E-13 A11 1.3373521E-14 2.8148712E-14 1.2507812E-13 -1.9267806E-13 A12 -4.8048317E-17 8.6680885E-16 -5.0186965E-15 6.6708490E-15 A13 -6.1267822E-18 -4.2101274E-17 -1.1764831E-16 3.1181752E-16 A14 6.8271249E-20 4.3897024E-19 5.7819606E-18 -1.4916583E-17 A15 1.0154937E-21 3.0537257E-21 4.2155913E-20 -1.8928223E-19 A16 -1.5549882E-23 -6.8802466E-23 -2.3426352E-21 1.1018974E-20

[0215] Sn 17 18 KA 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 A4 6.3367805E-06 8.6417697E-06 A5 -7.4088783E-07 -9.2291065E-07 A6 1.9025540E-08 3.0868118E-08 A7 5.3244708E-10 1.3236870E-09 A8 -6.0739091E-13 -9.1432979E-11 A9 -2.1708094E-13 -8.0775489E-13 A10 -1.5912104E-15 1.7941146E-13

[0216] [Table 16]

[0217] Example 4

[0218]

[0219] [Example 5]

[0220] The structure and the cross-sectional view of the light beam of the zoom lens of Example 5 are shown in Figure 14 . The zoom lens of Example 5 includes, in order from the magnifying side to the reducing side, a first lens group G1, a second lens group G2, a third lens group G3, a fourth lens group G4, a fifth lens group G5, and a sixth lens group G6. The intermediate group GM includes the fifth lens group G5, and the final lens group GE includes the sixth lens group G6. During zooming, the first lens group G1 and the sixth lens group G6 remain stationary, and the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 move along the optical axis Z while changing the intervals in the optical axis direction between the adjacent lens groups.

[0221] The first lens group G1 includes, in order from the magnification side to the reduction side, a first partial group G1A having a negative optical power, a first partial group G1B having a negative optical power, and a first partial group G1C having a positive optical power. The first partial group G1A includes three lenses L11 to L13 in order from the magnification side to the reduction side. The first partial group G1B includes one lens L14. The first partial group G1C includes two lenses L15 to L16 in order from the magnification side to the reduction side. During focusing, only the first partial group G1B moves, and the first partial group G1A and the first partial group G1C do not move.

[0222] The second lens group G2 includes one lens L21. The third lens group G3 includes one lens L31. The fourth lens group G4 includes one lens L41. The fifth lens group G5 includes six lenses L51 to L56 in order from the magnification side to the reduction side. The sixth lens group G6 includes one lens L61.

[0223] Regarding the zoom lens of Example 5, the basic lens data are shown in Table 17, the specifications and variable surface intervals during zooming are shown in Table 18, the aspherical coefficients are shown in Table 19, and the variable surface intervals during focusing are shown in Table 20. Also, regarding the zoom lens of Example 5, the aberration diagrams in the state where the projection distance is infinity are shown in Figure 15 , and the aberration diagrams in the state where the projection distance is 1370 mm (millimeters) are shown in Figure 16 .

[0224] [Table 17]

[0225] Example 5

[0226] Sn R D Nd v d *1 -30.8985 5.3002 1.53638 56.09 *2 -48.1080 5.1545 3 54.5321 1.5007 1.65160 58.54 4 22.3987 14.0494 5 -43.3816 1.1999 1.84666 23.78 6 209.2954 5.6429 *7 -34.3323 5.9991 1.53638 56.09 *8 -38.0471 8.2175 9 -68.3779 1.2006 1.49700 81.61 10 93.8309 0.8542 11 165.7756 5.8035 1.80610 33.27 12 -67.4475 DD

[12] 13 66.8886 5.8614 1.83400 37.21 14 -1518.3842 DD

[14] 15 60.0400 5.4147 1.48749 70.44 16 -119.7209 DD

[16] *17 -56.4298 1.4995 1.85135 40.10 *18 8043.8179 DD

[18] 19 77.5823 5.0005 1.77250 49.60 20 25.0253 0.1709 21 26.2121 10.3556 1.48749 70.44 22 -18.5745 0.0806 23 -18.3402 0.8999 1.79952 42.24 24 -177.7311 0.2000 25 70.2223 7.8378 1.49700 81.61 26 -29.4985 0.1600 27 121.9580 1.0000 1.83400 37.21 28 30.6435 8.1316 1.43700 95.10 29 -88.5323 DD

[29] 30 51.8202 4.7437 1.80610 33.27 31 -1195.4826 13.5650 32 ∞ 31.4200 1.51680 64.20 33 ∞ 0.2130

[0227] [Table 18]

[0228] Example 5

[0229] WIDE MIDDLE TELE Zr 1.0 1.3 1.7 f 11.72 15.00 19.92 FNo. 1.70 1.85 2.05 2ω[°] 90.6 76.4 61.2 DD

[12] 29.06 13.68 0.51 DD

[14] 29.03 27.42 14.40 DD

[16] 2.36 7.41 15.12 DD

[18] 10.98 10.57 13.08 DD

[29] 0.50 12.84 28.80

[0230] [Table 19]

[0231] Example 5

[0232] Sn 1 2 7 8 KA -1.9827586E+00 -1.0000009E+01 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 0.0000000E+00 0.0000000E+00 A4 7.8899550E-05 8.4142505E-05 8.3194553E-06 6.6221137E-06 A5 -2.5748457E-06 -7.8436610E-06 2.5570382E-06 8.3415093E-07 A6 -7.5661721E-08 8.5974054E-07 -3.9217111E-07 -9.2512700E-08 A7 2.7157610E-09 -7.4522854E-08 1.2661939E-08 -2.5668273E-09 A8 2.2281151E-10 3.5088528E-09 1.8394134E-09 8.4361743E-10 A9 -1.0461752E-11 -7.0071904E-11 -1.4173494E-10 -1.4763035E-11 A10 -3.9277483E-14 -3.6032902E-13 -2.1433831E-12 -2.7562005E-12 A11 8.8665871E-15 2.7110038E-14 4.1200018E-13 6.0822432E-14 A12 -7.2908704E-17 5.4643971E-16 -2.0726041E-15 5.8025007E-15 A13 -3.5606585E-18 -3.4557185E-17 -5.2790767E-16 -9.0327259E-17 A14 5.2558238E-20 4.1821827E-19 5.9931878E-18 -7.4132495E-18 A15 5.2608354E-22 2.4871692E-21 2.5306543E-19 4.8516383E-20 A16 -1.0031874E-23 -6.6828400E-23 -3.3852543E-21 4.0789282E-21

[0233] Sn 17 18 KA 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 A4 -3.6549799E-06 -5.4253042E-06 A5 -6.3237048E-08 -5.6569446E-08 A6 2.7156596E-08 3.6156011E-08 A7 1.6425360E-10 -1.4812181E-09 A8 -8.4054135E-11 -2.1102283E-11 A9 -1.5252706E-13 3.0307319E-12 A10 6.2637043E-14 -1.6184753E-13

[0234] [Table 20]

[0235] Example 5

[0236]

[0237] The corresponding values of conditional expressions (1) to (11) of the zoom lenses of Examples 1 to 5 are shown in Table 21. The values based on the d-line are shown in Table 21. The corresponding values of the examples shown in Table 21 can also be used as the upper or lower limits of the conditional expressions to set the preferred ranges of the conditional expressions.

[0238] [Table 21]

[0239] Formula number Example 1 Example 2 Example 3 Example 4 Example 5 (1) D23t / D23w 0.15 0.68 0.20 0.15 0.50 (2) 323t / β23w 1.89 1.61 1.83 2.17 1.65 (3) fG4 / fw -3.29 -2.11 -8.81 -7.00 -5.59 (4) fG1A / fG1C -0.02 -0.09 0.05 0.03 -0.08 (5) |fG1A / fG1B| 0.01 0.02 0.01 0.05 0.01 (6) fG1 / fw -1.97 -2.13 -1.92 -1.99 -2.14 (7) vave 81.61 81.61 81.61 95.10 81.61 (8) fG2 / fw 6.36 6.37 7.46 5.99 6.53 (9) fG3 / fw 7.69 6.66 7.27 7.95 7.05 (10) fGE / fw 5.37 5.33 5.49 6.04 5.23 (11) Bf / fw 3.03 2.96 2.94 2.94 2.94

[0240] The zoom lenses of Examples 1 to 5 are configured to be small, but the maximum full viewing angle at the wide-angle end is 75 degrees or more, the zoom ratio is 1.4 times or more, and wide-angle and high zoom ratio are achieved. Moreover, in the zoom lenses of Examples 1 to 5, various aberrations are well corrected, and furthermore, aberration variations during zooming and focusing are well suppressed, thereby achieving high optical performance.

[0241] Next, a projection display device according to an embodiment of the present invention will be described. Figure 17 It is a schematic configuration diagram of a projection display device according to an embodiment of the present invention. Figure 17 The projection display device 100 shown has: a zoom lens 10 according to an embodiment of the present invention; a light source 15; and transmissive display elements 11a to 11c as light valves, which correspond to light of each color and output an optical image. Moreover, the projection display device 100 has dichroic mirrors 12 and 13 for color separation, a cross dichroic prism 14 for color synthesis, condenser lenses 16a to 16c, and total reflection mirrors 18a to 18c for deflecting the optical path. In addition, Figure 17 the zoom lens 10 is schematically illustrated. And, an integrator is disposed between the light source 15 and the dichroic mirror 12, but its illustration is omitted in Figure 17 the figure.

[0242] The white light from the light source 15 is decomposed into three color light beams (blue light, green light, and red light) by the dichroic mirrors 12 and 13, and then respectively passes through the condenser lenses 16a to 16c and is incident on the transmissive display elements 11a to 11c corresponding to the color light beams of each color and is modulated. After color synthesis by the cross dichroic prism 14, it is incident on the zoom lens 10. The zoom lens 10 projects an optical image based on the modulated light modulated by the transmissive display elements 11a to 11c onto the screen 105.

[0243] Figure 18 It is a schematic configuration diagram of a projection display device according to another embodiment of the present invention. Figure 18The projection display device 200 shown has: a zoom lens 210 according to an embodiment of the present invention; a light source 215; and DMD (Digital Micromirror Device: registered trademark) elements 21a to 21c as light valves, which output optical images corresponding to light of each color. Further, the projection display device 200 has TIR (Total Internal Reflection) prisms 24a to 24c for color separation and color synthesis, and a polarization beam splitter prism 25 for separating illumination light and projection light. In addition, in Figure 18 the zoom lens 210 is schematically illustrated. An integrator is disposed between the light source 215 and the polarization beam splitter prism 25, but its illustration is omitted in Figure 18 the figure.

[0244] After the white light from the light source 215 is reflected by the reflection surface inside the polarization beam splitter prism 25, it is decomposed into three-color light beams (blue light, green light, and red light) by the TIR prisms 24a to 24c. The decomposed light beams of each color are respectively incident on the corresponding DMD elements 21a to 21c and are modulated, and then travel in the opposite direction again in the TIR prisms 24a to 24c for color synthesis, and then transmit through the polarization beam splitter prism 25 and are incident on the zoom lens 210. The zoom lens 210 projects an optical image based on the modulated light modulated by the DMD elements 21a to 21c onto the screen 205.

[0245] Figure 19 is a schematic structural diagram of a projection display device according to another embodiment of the present invention. Figure 19 The projection display device 300 shown has: a zoom lens 310 according to an embodiment of the present invention; a light source 315; and reflective display elements 31a to 31c as light valves, which output optical images corresponding to light of each color. Further, the projection display device 300 has dichroic mirrors 32 and 33 for color separation, a cross dichroic prism 34 for color synthesis, a total reflection mirror 38 for deflecting the optical path, and polarization beam splitter prisms 35a to 35c. In addition, in Figure 19 the zoom lens 310 is schematically illustrated. An integrator is disposed between the light source 315 and the dichroic mirror 32, but its illustration is omitted in Figure 19 the figure.

[0246] The white light from the light source 315 is decomposed into three-color light beams (blue light, green light, and red light) by the dichroic mirrors 32 and 33. Each decomposed color light beam passes through the polarization beam split prisms 35a to 35c and is incident on the reflective display elements 31a to 31c corresponding to the respective color light beams, where it is modulated. After color synthesis by the cross dichroic prism 34, it is incident on the zoom lens 310. The zoom lens 310 projects an optical image based on the modulated light modulated by the reflective display elements 31a to 31c onto the screen 305.

[0247] Figure 20 and Figure 21 FIG. and FIG.

[0247] are external views of a camera 400, which is an imaging device according to an embodiment of the present invention. Figure 20 FIG. Figure 20 shows a perspective view of the camera 400 as viewed from the front side, Figure 21 and FIG. Figure 21 shows a perspective view of the camera 400 as viewed from the back side. The camera 400 is detachably mounted with an interchangeable lens 48 and is a mirrorless single-lens digital camera. The interchangeable lens 48 houses a zoom lens 49 according to the embodiment of the present invention in the lens barrel.

[0248] 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. Further, an operation unit 44, an operation unit 45, and a display unit 46 are provided on the back surface of the camera body 41. The display unit 46 displays the captured image and the image existing within the perspective before shooting.

[0249] A photographic aperture through which light from a photographic object enters is provided at the center of the front surface of the camera body 41, and a bayonet mount 47 is provided at a position corresponding to the photographic aperture. The interchangeable lens 48 is mounted on the camera body 41 via the bayonet mount 47.

[0250] An imaging element 50 is provided in the camera body 41. The imaging element 50 outputs a video signal corresponding to the subject image formed by the interchangeable lens 48. As the imaging element 50, for example, a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) can be used. In the camera body 41, a signal processing circuit (not shown) and a recording medium (not shown) are provided. The signal processing circuit processes the video signal output from the imaging element 50 to generate an image. The recording medium is used to record the generated image. In the camera 400, by pressing the shutter button 42, a still image or a moving image can be captured, and the image data obtained by the shooting is recorded in the above recording medium.

[0251] As described above, the technology of the present invention has been described by way of embodiments and examples, but the technology of the present invention is not limited to the above embodiments and examples, and various modifications can be made. For example, the radius of curvature, surface interval, refractive index, Abbe number, aspheric coefficient, etc. of each lens are not limited to the values shown in the above respective examples, and other values can be adopted.

[0252] In addition, the projection display device related to the technology of the present invention is not limited to the above structure. For example, the optical components and light valves for beam separation or beam combination can be changed in various ways. The light valve is not limited to the mode of spatially modulating the light from the light source by the image display element and outputting an optical image based on the image data. It can also be a mode of outputting the light itself output from the self-luminous image display element as an optical image based on the image data. As the self-luminous image display element, for example, an image display element formed by two-dimensionally arranging light-emitting elements such as LEDs (Light Emitting Diodes) or OLEDs (Organic Light Emitting Diodes) can be cited.

[0253] Moreover, the imaging device related to the technology of the present invention is not limited to the above structure. For example, it can be configured in various ways such as cameras other than the mirrorless type, film cameras, video cameras, security cameras, and movie cameras.

[0254] Regarding the above embodiments and examples, the following additional remarks are further disclosed.

[0255] [Supplementary Note 1]

[0256] A zoom lens that sequentially includes, from the telephoto side to the wide-angle side, a first lens group having a negative optical power, a second lens group having a positive optical power, a third lens group having a positive optical power, a fourth lens group having a negative optical power, an intermediate group including one or more lens groups, and a final lens group having a positive optical power, wherein

[0257] the first lens group sequentially includes, from the telephoto side to the wide-angle side, a first A partial group, a first B partial group, and a first C partial group having a negative optical power,

[0258] during focusing, the interval between the first A partial group and the first B partial group changes, and the interval between the first B partial group and the first C partial group changes,

[0259] during zooming, the first lens group and the final lens group remain stationary, and all the lens groups within the second lens group, the third lens group, the fourth lens group, and the intermediate group change the interval in the optical axis direction between adjacent lens groups and move along the optical axis,

[0260] The distance between the second lens group and the third lens group at the telephoto end is shorter than the distance between the second lens group and the third lens group at the wide-angle end.

[0261] [Supplementary Note 2]

[0262] For the zoom lens according to Supplementary Note 1, wherein

[0263] when the distance between the second lens group and the third lens group at the telephoto end is set as D23t,

[0264] and the distance between the second lens group and the third lens group at the wide-angle end is set as D23w,

[0265] the following conditional formula (1) is satisfied:

[0266] D23t / D23w < 1 (1).

[0267] [Supplementary Note 3]

[0268] For the zoom lens according to Supplementary Note 1 or 2, wherein

[0269] when the combined lateral magnification of the second lens group and the third lens group at the telephoto end is set as β23t,

[0270] and the combined lateral magnification of the second lens group and the third lens group at the wide-angle end is set as β23w,

[0271] the following conditional formula (2) is satisfied:

[0272] 1.4 < β23t / β23w < 3 (2).

[0273] [Supplementary Note 4]

[0274] For the zoom lens according to any one of Supplementary Notes 1 to 3, wherein

[0275] when the focal length of the fourth lens group is set as fG4,

[0276] and the focal length of the zoom lens at the wide-angle end is set as fw,

[0277] the following conditional formula (3) is satisfied:

[0278] -15 < fG4 / fw < -1 (3).

[0279] [Supplementary Note 5]

[0280] For the zoom lens according to any one of Supplementary Notes 1 to 4, wherein

[0281] When setting the focal length of the first part group 1A as fG1A,

[0282] and setting the focal length of the first part group 1C as fG1C,

[0283] the following conditional expression (4) is satisfied:

[0284] -0.5 < fG1A / fG1C < 0.5 (4).

[0285] [Supplementary Note 6]

[0286] The zoom lens according to any one of Supplementary Notes 1 to 5, wherein

[0287] when setting the focal length of the first part group 1A as fG1A,

[0288] and setting the focal length of the first part group 1B as fG1B,

[0289] the following conditional expression (5) is satisfied:

[0290] 0 < |fG1A / fG1B| < 0.3 (5).

[0291] [Supplementary Note 7]

[0292] The zoom lens according to any one of Supplementary Notes 1 to 6, wherein

[0293] when setting the focal length of the first lens group as fG1,

[0294] and setting the focal length of the zoom lens at the wide-angle end as fw,

[0295] the following conditional expression (6) is satisfied:

[0296] -4 < fG1 / fw < -1 (6).

[0297] [Supplementary Note 8]

[0298] The zoom lens according to any one of Supplementary Notes 1 to 7, wherein

[0299] when focusing, the first part group 1C does not move.

[0300] [Supplementary Note 9]

[0301] The zoom lens according to any one of Supplementary Notes 1 to 8, wherein

[0302] the first part group 1C includes at least one negative lens,

[0303] when setting the average value of the Abbe numbers of all the negative lenses included in the first part group 1C based on the d-line as vave,

[0304] Satisfy the conditional expression (7) represented as follows:

[0305] v ave>50 (7).

[0306] [Appendix Note 10]

[0307] The zoom lens according to any one of Appendix Notes 1 to 9, wherein

[0308] The telephoto side is telecentric.

[0309] [Appendix Note 11]

[0310] The zoom lens according to any one of Appendix Notes 1 to 10, wherein

[0311] When the focal length of the second lens group is set to fG2,

[0312] and the focal length of the zoom lens at the wide-angle end is set to fw,

[0313] Satisfy the conditional expression (8) represented as follows:

[0314] 2 < fG2 / fw < 10 (8).

[0315] [Appendix Note 12]

[0316] The zoom lens according to any one of Appendix Notes 1 to 11, wherein

[0317] When the focal length of the third lens group is set to fG3,

[0318] and the focal length of the zoom lens at the wide-angle end is set to fw,

[0319] Satisfy the conditional expression (9) represented as follows:

[0320] 4 < fG3 / fw < 12 (9).

[0321] [Appendix Note 13]

[0322] The zoom lens according to any one of Appendix Notes 1 to 12, wherein

[0323] When the focal length of the final lens group is set to fGE,

[0324] and the focal length of the zoom lens at the wide-angle end is set to fw,

[0325] Satisfy the conditional expression (10) represented as follows:

[0326] 3 < fGE / fw < 8 (10).

[0327] [Appendix Note 14]

[0328] The zoom lens according to any one of Appendices 1 to 13, wherein,

[0329] when the back focal length on the reduction side of the zoom lens in terms of air equivalent distance is set to Bf,

[0330] and the focal length of the zoom lens at the wide-angle end is set to fw,

[0331] the following conditional expression (11) is satisfied:

[0332] 2 < Bf / fw (11).

[0333] [Appendix 15]

[0334] The zoom lens according to any one of Appendices 1 to 14, wherein,

[0335] the intermediate group includes, on the reduction side, a cemented lens formed by sequentially cementing a negative lens and a positive lens from the magnification side to the reduction side.

[0336] [Appendix 16]

[0337] The zoom lens according to any one of Appendices 1 to 15, wherein,

[0338] the first C partial group includes a negative lens and a positive lens in this order from the magnification side to the reduction side.

[0339] [Appendix 17]

[0340] A projection display device including the zoom lens according to any one of Appendices 1 to 16.

[0341] [Appendix 18]

[0342] An imaging device including the zoom lens according to any one of Appendices 1 to 16.

Claims

1. A zoom lens, comprising, from the magnification side to the reduction side, a first lens group with negative power, a second lens group with positive power, a third lens group with positive power, a fourth lens group with negative power, an intermediate group including one or more lens groups, and a final lens group with positive power, wherein: The first lens group includes, from the magnification side to the reduction side, a 1A portion group, a 1B portion group and a 1C portion group having negative optical power. When focusing, the interval between the 1A group and the 1B group changes, and the interval between the 1B group and the 1C group changes, When changing the magnification, the first lens group and the final lens group remain stationary, and the second lens group, the third lens group, the fourth lens group and all lens groups in the intermediate group change the intervals in the optical axis direction between the adjacent lens groups and move along the optical axis. The distance between the second lens group and the third lens group at the telephoto end is shorter than the distance between the second lens group and the third lens group at the wide angle end.

2. The zoom lens according to claim 1, wherein: When the distance between the second lens group and the third lens group at the telephoto end is set to D23t, When the distance between the second lens group and the third lens group at the wide angle end is set to D23w, The following condition (1) is satisfied: D23t / D23w<1 (1).

3. The zoom lens according to claim 1 or 2, wherein: When the combined lateral magnification of the second lens group and the third lens group at the telephoto end is set to β23t, When the combined lateral magnification of the second lens group and the third lens group at the wide angle end is β23w, The following condition (2) is satisfied: 1.4<β23t / 23w<3 (2).

4. The zoom lens according to claim 1 or 2, wherein: When the focal length of the fourth lens group is set to fG4, When the focal length of the zoom lens at the wide angle end is fw, The following condition (3) is satisfied: -15 <fG4 / fw<-1 (3)。 5. The zoom lens according to claim 1 or 2, wherein: When the focal length of the 1A part group is set to fG1A, When the focal length of the 1C partial group is set to fG1C, The following condition (4) is satisfied: -0.5 <fG1A / fG1C<0.5 (4)。 6. The zoom lens according to claim 1 or 2, wherein: When the focal length of the 1A part group is set to fG1A, When the focal length of the 1B subgroup is set to fG1B, The following condition (5) is satisfied: 0<|fG1A / fG1B|<0.3 (5).

7. The zoom lens according to claim 1 or 2, wherein: When the focal length of the first lens group is set to fG1, When the focal length of the zoom lens at the wide angle end is fw, The following condition (6) is satisfied: -4 <fG1 / fw<-1 (6)。 8. The zoom lens according to claim 1 or 2, wherein: When focusing, the 1C portion group does not move.

9. The zoom lens according to claim 1 or 2, wherein: The first C part group includes at least one negative lens, When the average value of the d-line-based Abbe numbers of all negative lenses included in the 1C partial group is denoted as v ave, The following condition (7) is satisfied: v ave>50 (7).

10. The zoom lens according to claim 1 or 2, wherein: The reduced side is telecentric.

11. The zoom lens according to claim 1 or 2, wherein: When the focal length of the second lens group is set to fG2, When the focal length of the zoom lens at the wide angle end is fw, The following condition (8) is satisfied: 2<fG2 / fw<10 (8).

12. The zoom lens according to claim 1 or 2, wherein: When the focal length of the third lens group is set to fG3, When the focal length of the zoom lens at the wide angle end is fw, The following condition (9) is satisfied: 4<fG3 / fw<12 (9).

13. The zoom lens according to claim 1 or 2, wherein: When the focal length of the final lens group is set to fGE, When the focal length of the zoom lens at the wide angle end is fw, The following condition (10) is satisfied: 3 <fGE / fw<8 (10)。 14. The zoom lens according to claim 1 or 2, wherein: When the back focus of the zoom lens on the reduction side measured in terms of air conversion distance is Bf, When the focal length of the zoom lens at the wide angle end is fw, The following condition (11) is satisfied: 2 <Bf / fw (11)。 15. The zoom lens according to claim 1 or 2, wherein: The intermediate group includes, on the most reduction side, a cemented lens in which a negative lens and a positive lens are cemented in order from the magnification side to the reduction side.

16. The zoom lens according to claim 1 or 2, wherein: The 1C partial group includes a negative lens and a positive lens in order from the magnification side to the reduction side. 17 . A projection display device comprising the zoom lens according to claim 1 . 18 . An imaging device comprising the zoom lens according to claim 1 .

Images