JP4957124B2 - Zoom lens - Google Patents

Description

  The present invention relates to a zoom lens.

  Recently, compact and high-performance projectors using DMD (Digital Micro-Mirror Device) and liquid crystal devices as display elements are rapidly spreading in presentations at conferences, digital broadcasting at home, home theaters, and the like. As display elements become smaller and higher in resolution, projection zoom lenses (hereinafter referred to as zoom lenses) are also required to be smaller and have higher performance. Needs to be sufficiently corrected, and there is a case where a wide angle is required so that a large screen can be projected in a narrower room.

  For example, in a DLP (Digital Light Processing) projector that magnifies and displays light reflected on a DMD mirror on a projection object such as a screen through a zoom lens, although it cannot be generally stated depending on the specifications of the projector, the chromatic aberration of magnification is at least 1 It is often required to be within about a pixel, and the current smallest pixel is about 10 μm. Further, in the case of a so-called single-plate DLP projector that projects one DMD sheet, it is required to reduce axial chromatic aberration. For example, in the case of a so-called three-plate projector having a DMD corresponding to each color of RGB, the axial chromatic aberration is adjusted to some extent by adjusting the position of the DMD corresponding to each color. can do. However, in the case of the single plate type, since the position of the DMD is determined, it is necessary to reduce the axial chromatic aberration of the zoom lens. Although it depends on the F number of the optical system, it is desired that the zoom lens of F2.5 is at least about 40 μm, for example.

  With respect to aberrations other than lateral chromatic aberration and axial chromatic aberration, higher performance is required of the zoom lens due to downsizing of the DMD.

  In response to the above demands, there are the following zoom lenses.

  First, in order from the enlargement side, a first group having a negative refractive power, a second group having a positive refractive power, a third group having a positive refractive power, a fourth group having a negative refractive power, and a positive or negative value. A zoom lens that is substantially telecentric on the reduction side and has six components, i.e., a fifth group having a refractive power of 6 and a sixth group having a positive refractive power, and the third group at the time of zooming from the telephoto end to the wide-angle end There is a zoom lens in which the fifth group moves from the enlargement side to the reduction side, and the fourth group has a stop (see Patent Document 1).

Further, there is a zoom lens in which the entire system is configured by at least six optical components, at least four of the optical components move during zooming, and the optical component closest to the magnification side has negative optical power (patent) Reference 2).
JP 2002-350727 A JP 2001-235679 A

  In a zoom lens using a DMD as a display element, light (projection light) emitted from a DMD ON pixel (a micromirror in which the light incident on the DMD from the light source is emitted from the zoom lens and turned to reach the screen) Is reflected by the lens surface arranged in the lens group close to the DMD, and this reflected light is turned off in the DMD OFF pixel (micrometer in which the direction of the light incident on the DMD from the light source is not emitted from the zoom lens). It may be reflected again by the mirror. This is shown in FIG.

  In FIG. 37 (a), 50 is a display element DMD, 52 is an ON pixel in the DMD 50, 53 is an OFF pixel in the DMD 50, 55 is a prism, 57 is a lens surface that reflects light from the DMD, Reference numeral 60 denotes a light beam traveling from the ON pixel to the screen, and 62 denotes a light beam traveling from the OFF pixel to the screen. Light that enters the display element 50 via the prism 55 is omitted. The light incident on the ON pixel 52 is reflected and proceeds to the screen side. At this time, for example, a part of the light incident on the lens surface 57 is reflected, enters the OFF pixel 53, is reflected again, and travels toward the screen again.

  As shown in FIG. 37, the reflected light from the OFF pixel 53 reaches the screen mixed with the original projection light that forms an image on the screen depending on the reflection angle. Therefore, the light reflected again reaches a position on the screen where the light does not reach because it is a position corresponding to an OFF pixel (this phenomenon is hereinafter referred to as ON / OFF ghost). The occurrence of the ON / OFF ghost does not provide a desirable image quality for an observer who observes an image on the screen because a dark place on the screen is originally brightened. In particular, when the image projected on the screen is a dark scene, the ON / OFF ghost is easier to see and does not have a desirable image quality.

  FIG. 37B shows in detail how the light beam reflected from the ON pixel 52 is reflected by the lens surface 57 and enters the OFF pixel. Reference numeral 70 shown in FIG. 37B indicates a position in a conjugate relationship with the reflective surface of the ON pixel 52 and the lens surface 57. When the position 70 in the conjugate relationship is close to or coincides with the pixel, particularly the reflective surface of the OFF pixel 53, a small and bright light spot is formed on the OFF pixel 53. The brighter the light spot is, the more the above-mentioned ON / OFF ghost can be recognized by an observer who observes the screen, which is not preferable in forming an image on the screen.

  However, the zoom lens described in Patent Document 1 is a zoom lens suitable for a single-plate projector equipped with a DMD, but no consideration is given to the above-described ON / OFF ghost. As a method for making the ON / OFF ghost less likely to occur, the back focus Bf (distance on the optical axis from the center of the final lens surface on the reduction side of the zoom lens to the display element surface arranged perpendicular to the optical axis) is used. Although there is a method of lengthening the lens, it is difficult to reduce the size of the zoom lens because it is necessary to increase the size of a prism such as a TIR (Total Internal Reflection) type disposed on the reduction side of the lens group or the sixth group. Therefore, it is difficult to reduce the size of a projector that is a projection apparatus having this zoom lens.

  The zoom lens described in Patent Document 2 has a configuration in which four groups out of six groups are moved, but there is no description regarding the above-described ON / OFF ghost. Further, since there are many moving groups, the structure is complicated and there are many structural parts, so that the assembly is not easy and the cost increases.

  In recent years, zoom lenses for home theater applications require a complex mechanism that changes the aperture diameter according to the image conditions. To accommodate this, the lens group equipped with the aperture must be scaled. It is desired to have a configuration that does not move by operation.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a zoom lens having a simple configuration, high image quality, and high performance.

  Said subject is solved by the following structures.

1. In the zoom lens composed of six groups, the first group to the sixth group in order from the magnification side for enlarging and projecting the display element,
A first group having a negative refractive power; a second group that moves when zooming with a positive refractive power; a fifth group that moves when zooming with a positive refractive power; a sixth group having a positive refractive power; With
Furthermore, the third group that moves at the time of zooming with positive or negative refractive power and the fourth group with negative refractive power having a stop, or the third group with negative refractive power that has a stop and positive or negative Any one of the fourth group moving at the time of zooming with refractive power,
The sixth group consists of one positive lens, and satisfies the following conditional expression:
1.35 ≦ Bf / CR1 × F ≦ 2.00
However,
Bf: distance on the optical axis from the center of the lens surface on the reduction side of the positive lens in the sixth group to the display element surface arranged perpendicular to the optical axis CR1: curvature on the enlargement side of the positive lens in the sixth group Radius F: Minimum F value of zoom lens
And
When the third group has a negative refractive power and a stop and the fourth group moves at the time of zooming with a positive or negative refractive power, among the positive lenses constituting the fourth group and the fifth group At least one of the positive lenses constituting the fifth group when the fourth group has a negative refractive power and a stop and the third group moves at the time of zooming with a positive or negative refractive power At least one sheet is made of a material that satisfies the following conditional expression:
nd> 1.58
νd> 59
However,
nd: refractive index with respect to d-line (wavelength 587.56 nm) νd: Abbe number with respect to d-line (wavelength 587.56 nm)
And
Furthermore, the following conditional expression is satisfied ,
1.70 ≦ fxw / fw ≦ 4.80
However,
fxw: the fourth group and the fifth group when the zoom lens is at the wide-angle end when the third group has a negative refractive power and a stop and the fourth group moves with a positive or negative refractive power upon zooming When the fourth group has a negative refractive power and a stop and the third group moves at the time of zooming with a positive or negative refractive power, the focal length fw of the fifth group: a zoom lens Focal length with wide angle end
And
The zoom lens according to claim 6, wherein the positive lens in the sixth group satisfies the following conditional expression.
−1 / 3 ≦ CR1 / CR2 ≦ 1/3
However,
CR1: Radius of curvature on the enlargement side of the sixth lens group positive lens
CR2: radius of curvature of the sixth group positive lens on the display element side
It is.
2. 2. The zoom lens according to 1, wherein the following conditional expression is satisfied.
1.70 ≦ fxt / ft ≦ 3.70
However,
fxt: the fourth group and the fifth group when the zoom lens is at the telephoto end when the third group has a negative refracting power and a stop and the fourth group moves at the time of zooming with a positive or negative refracting power When the fourth group has a negative refracting power and a stop and the third group moves at the time of zooming with a positive or negative refracting power, the focal length of the fifth group ft: zoom lens 2. Focal length at the telephoto end The zoom lens according to 1 or 2, wherein the positive lens of the sixth group is made of a material that satisfies the following conditional expression.
nd> 1.60
However,
Refractive index for nd: d line (wavelength: 587.56 nm) The zoom lens according to 1 or 2, wherein the positive lens of the sixth group is made of a material that satisfies the following conditional expression.
nd> 1.68
However,
nd: refractive index for d-line (wavelength 587.56 nm)
5 . The sixth group of the positive lens, the zoom lens according to any one of 1 to 4, characterized in that the following conditional expression is satisfied.
0.75 ≦ Bf / f6 × F ≦ 1.60
However,
Bf: distance on the optical axis from the center of the lens surface on the reduction side of the positive lens in the sixth group to the display element surface arranged perpendicular to the optical axis f6: focal length of the sixth group F: zoom lens Minimum F value
6 . The display element is a zoom lens according to any one of 1 to 5, characterized in that the DMD.

According to the present invention, the zoom lens is as follows.
(1) Three lens groups that do not have a diaphragm are composed of six lens groups that are moved during zooming. The sixth group is composed of one positive lens, and the radius of curvature of the positive lens is appropriately determined. ing.
(2) When the third group has a negative refractive power and a stop, and the fourth group moves at the time of zooming with a positive or negative refractive power, at least of the positive lenses constituting the fourth group and the fifth group When one lens has a negative refractive power and a diaphragm and the third lens group moves at the time of zooming with a positive or negative refractive power, at least one of the positive lenses constituting the fifth lens group Appropriate refractive index and Abbe number are set.
(3) When the third group has a negative refractive power and a stop, and the fourth group moves at the time of zooming with a positive or negative refractive power, the combined wide-angle end focal point consisting of the fourth group and the fifth group Distance, or when the fourth group has a negative refractive power and a stop, and the third group moves at the time of zooming with a positive or negative refractive power, the focal length of the fifth group and the focal length of the wide angle end of the zoom lens The relationship with is properly determined.

  According to the above (1) to (3), the lens group provided with the aperture does not move, ON / OFF ghost is suppressed without increasing the back focus, and field curvature, axial chromatic aberration, and lateral chromatic aberration are excellent. Thus, telecentricity for the display element is ensured.

  Therefore, it is possible to provide a zoom lens having a simple configuration and high image quality and high performance.

  Although the present invention will be described based on the illustrated embodiment, the present invention is not limited to the embodiment. Each embodiment described below is a zoom lens suitable as a projection optical system (that is, a magnifying system) for a projection apparatus including a display element (particularly, a single-plate projector equipped with a DMD as a display element). Of course, it can also be used as an imaging optical system (that is, a reduction system) for an imaging apparatus (for example, a video camera, a digital camera, a digital video unit, etc.) provided with an imaging element instead of a display element.

  The zoom lens according to the present invention is composed of six groups. The first group is Gr1 from the enlargement side (screen side in the DLP projector), and the most reduction side (display element side in the DLP projector) is the sixth group.

  The screen surface on the enlargement side and the DMD which is the display element on the reduction side have a conjugate relationship. In general, the screen surface is at the conjugate point with the longer distance (enlarged conjugate side), and the DMD is at the conjugate point with the shorter distance ( This corresponds to the reduction conjugate side).

  In the zoom lens, the first group Gr1 has a negative refractive power, the second group Gr2 has a positive refractive power, the fifth group Gr5 has a positive refractive power, and the sixth group Gr5 has a positive refractive power. When the configuration of the refractive powers of the six groups of the zoom lens are arranged side by side with “positive” or “negative” representing the refractive power from the magnification side, they are negative, positive, x, negative, y, positive, and positive. Here, x and y are lens groups whose refractive power can be positive or negative, and when either x or y is provided, the other does not exist. In other words, the refractive power of the lens group has a negative, positive, x, negative, positive, positive, or negative, positive, negative, y, positive, positive configuration in order from the magnification side. The former is the first zoom lens and the latter is the second zoom lens.

  The configuration of the first zoom lens of negative / positive / x / negative / positive / positive is as follows. The first group Gr1 (negative) on the most enlarged side has a focus function, and is moved during focusing. The combined refractive power of the second group Gr2 (positive) and the third group Gr3 (x) is positive. The refractive power of the third group Gr3 (x) is positive when the zoom effect is prioritized, and the aberration is Negative if priority is given to the effect of trimming. Further, since the second group Gr2 (positive) and the third group Gr3 (x) have a scaling function, they are moved during scaling. The fourth group Gr4 (negative) includes a stop ST. The fifth group Gr5 (positive) has a scaling function, and is moved during scaling. The sixth group Gr6 (positive) is on the most reduction side.

  The configuration of the second zoom lens of negative / positive / negative / y / positive is as follows. Since the first group Gr1 (negative) has a focus function, it is moved during focusing. Since the second group Gr2 (positive) has a scaling function, it is moved during scaling. The third group Gr3 (negative) includes a stop ST. The combined refractive power of the fourth group Gr4 (y) and the fifth group Gr5 (positive) is positive. The refractive power of the fourth group Gr4 is positive when the zooming effect is prioritized, and has the effect of adjusting aberrations. Negative if priority is given. The fourth group Gr4 (y) and the fifth group Gr5 (positive) are provided with a scaling function, and thus are moved during scaling. The sixth group Gr6 (positive) is on the most reduction side.

  In the zoom lens having either the first zoom lens or the second zoom lens described above, the zoom ratio (focal length at the telephoto end / focal length at the wide-angle end is set by setting the first group Gr1 to a negative refractive power. In a zoom lens having a small distance of about 1.3 times, which indicates a distance, which is also referred to as a zoom ratio, it is preferable to reduce the size of the zoom lens because the amount of extension can be small. Further, by setting the sixth group Gr6 to have a positive refractive power, it is possible to provide a zoom lens having substantially telecentricity on the DMD side on the reduction side, and suppress a reduction in the amount of light at the periphery of the projected image. Can do.

  In addition, the fourth group Gr4 of the first zoom lens including the diaphragm ST and the third group Gr3 of the second zoom lens are fixed without moving at the time of zooming, thereby moving the diaphragm mechanism with driving. Is no longer necessary. For this reason, the lens holding mechanism can be simplified and, for example, an actuator such as a pulse motor for driving the diaphragm can be fixed, so that the wiring for supplying power to the driving actuator is moved by the diaphragm. This eliminates the need to move it. For this reason, when the structure of the diaphragm mechanism, the lens holding mechanism, and the like can be facilitated, there is no problem that the diaphragm does not operate due to disconnection, and the reliability of the zoom lens can be increased. In particular, in recent years, in a DLP projector, it has become essential to change the aperture diameter in order to improve the projected image as a result of zooming. It is suitable for providing images with high reliability.

  A prism P1 and a parallel plate P2 are arranged on the reduction side of the sixth group Gr6. The prism P1 corresponds to a TIR prism for beam separation, and the parallel plate P2 corresponds to a cover glass of a DMD that is a display element. When the zoom lens of each embodiment is used for a three-plate projector, a color separation / color synthesis optical system (such as a cross dichroic prism) is also included in the prism P1.

  It is preferable to configure the sixth group Gr6 closest to the DMD with a single positive lens to have an appropriate surface shape because ON / OFF ghosts generated by reflection between the DMD and the lens surface can be reduced.

  The ON / OFF ghost has a conjugate relationship via a lens surface of a mirror (ON pixel) surface of a DMD that emits a light beam forming a projected image and a lens group disposed on the enlargement side, particularly a lens group close to the DMD. And the mirror surface of the DMD can be suppressed as far as possible. This is because the spot diameter of the light passing through the conjugate relationship and reaching the mirror surface of the DMD is large and dark by moving the conjugate conjugate position and the DMD mirror surface away from each other. It is preferable that the position of the conjugate relationship and the mirror surface of the DMD are separated by approximately 15 mm or more.

Therefore, in order to reduce the surface to be a reflective surface close to the DMD, the sixth lens unit is a single positive lens, and the surface shape of the single positive lens is appropriately set so as not to be in the above conjugate relationship. In order to specify, it is desirable to satisfy the following conditional expression (1).
1.35 ≦ Bf / CR1 × F ≦ 2.00 (1)
However,
Bf: distance on the optical axis from the center of the lens surface on the reduction side of the positive lens in the sixth group to the display element surface arranged perpendicular to the optical axis (back focus)
CR1: radius of curvature F on the enlargement side of the positive lens in the sixth group F: minimum F value of the zoom lens.

In addition, it is more desirable for the sixth group to satisfy the following conditional expressions (2) and (3).
−1 / 3 ≦ CR1 / CR2 ≦ 1/3 (2)
However,
CR1: radius of curvature on the enlargement side of the positive lens in the sixth group CR2: radius of curvature on the reduction side of the positive lens in the sixth group 0.75 ≦ Bf / f6 × F ≦ 1.60 (3)
However,
Bf: distance on the optical axis from the center of the lens surface on the reduction side of the positive lens in the sixth group to the display element surface arranged perpendicular to the optical axis f6: focal length of the sixth group F: zoom lens Minimum F value.

  Regarding conditional expressions (1) and (3), if the lower limit is exceeded, the conjugate position approaches the DMD, which is not preferable because ON / OFF ghost increases. On the other hand, if the upper limit is exceeded, the curvature of field is not good. Also, in conditional expression (2), when CR1 is large and exceeds the lower limit, the conjugate position approaches DMD, so the ON / OFF ghost increases, which is not preferable. When CR2 is small and exceeds the lower limit, field curvature is good. Not. Further, if the upper limit is exceeded, the conjugate position approaches the DMD, which is not preferable because ON / OFF ghost increases.

  As a simple configuration including one positive lens to which the sixth group Gr6 is fixed, the back focus can be lengthened by conforming to the conditional expressions (1), (2), and (3) as described above. ON / OFF ghost can be suppressed without increasing the lens group and prism.

When the third group has a negative refractive power and a stop and the fourth group moves at the time of zooming with a positive or negative refractive power, at least one of the positive lenses constituting the fourth group and the fifth group When the fourth lens unit has a negative refractive power and a stop and the third lens unit moves at the time of zooming with a positive or negative refractive power, at least one of the positive lenses constituting the fifth lens unit It is desirable that the positive lens is made of a material that satisfies the following conditional expressions (4) and (5).
nd> 1.58 (4)
νd> 59 (5)
However,
nd: Refractive index for d line (wavelength 587.56 nm) νd: Abbe number for d line (wavelength 587.56 nm). Note that νd can be defined by the following equation (5a).
νd = (nd−1) / (n _F −n _C ) (5a)
However,
n _F : Refractive index for F line (wavelength: 486.13 nm) n _C : Refractive index for C line (wavelength: 656.28 nm)

  When conditional expressions (4) and (5) are satisfied, it is possible to satisfactorily suppress field curvature, axial chromatic aberration, and lateral chromatic aberration. Further, it is possible to suppress the use of an expensive glass material with νd> 80 that is effective for satisfactorily suppressing axial chromatic aberration and lateral chromatic aberration. If the conditional expression (4) is not satisfied, the refractive index is not sufficiently large, and the field curvature cannot be improved. If conditional expression (5) is not satisfied, axial chromatic aberration and lateral chromatic aberration cannot be improved. When flint or heavy flint glass that does not satisfy conditional expression (5) is used, lateral chromatic aberration can be improved, but axial chromatic aberration cannot be improved.

When the third group has a stop, the focal length of the group consisting of the fourth group and the fifth group, and when the fourth group has a stop, the focal length of the fifth group satisfies the following conditional expression (6): It is preferable.
1.70 ≦ fxw / fw ≦ 4.80 (6)
However,
fxw: the fourth group and the fifth group when the zoom lens is at the wide-angle end when the third group has a negative refractive power and a stop and the fourth group moves with a positive or negative refractive power upon zooming When the fourth group has a negative refractive power and a stop and the third group moves at the time of zooming with a positive or negative refractive power, the focal length fw of the fifth group: a zoom lens This is the focal length when the wide-angle end is set.

  Exceeding the lower limit of conditional expression (6) is not preferable because chromatic aberration of magnification is excessively corrected, and there is a problem that it is difficult to ensure telecentricity with respect to a light beam that converges on the DMD. Exceeding the upper limit of conditional expression (6) is not preferable because both lateral chromatic aberration and field curvature cannot be improved.

When the third group has a negative refractive power and a stop and the fourth group moves at the time of zooming with a positive or negative refractive power, the focal length of the group consisting of the fourth group and the fifth group, the fourth group Has a negative refracting power and a stop, and the third group moves at the time of zooming with a positive or negative refracting power, it is more preferable that the focal length of the fifth group satisfies the following conditional expression (7).
1.70 ≦ fxt / ft ≦ 3.70 (7)
However,
fxt: the fourth group and the fifth group when the zoom lens is at the telephoto end when the third group has a negative refracting power and a stop and the fourth group moves at the time of zooming with a positive or negative refracting power When the fourth group has a negative refracting power and a stop and the third group moves at the time of zooming with a positive or negative refracting power, the focal length of the fifth group ft: zoom lens This is the focal length when the telephoto end is set.

  Exceeding the lower limit of conditional expression (7) is not preferable because chromatic aberration of magnification is excessively corrected, and there is a problem that it is difficult to ensure telecentricity with respect to a light beam that converges on the display element. Exceeding the upper limit of conditional expression (7) is not preferable because both lateral chromatic aberration and field curvature cannot be improved.

The positive lens in the sixth group is preferably made of a material that satisfies the following conditional expression (8), and more preferably satisfies the conditional expression (9).
nd> 1.60 (8)
nd> 1.68 (9)
However,
nd: a refractive index with respect to d-line (wavelength: 587.56 nm).

By satisfying conditional expression (8), and more desirably conditional expression (9), the curvature of field can be improved, and expensive flint glass and heavy flint glass are used in the embodiments described later. Since the number to be reduced can be reduced, it is possible to cope with low cost.

  In the first embodiment (FIG. 1), in zooming from the telephoto end (T) to the wide-angle end (W), the second group (Gr2) and the fifth group (Gr5) are both from the enlargement side to the reduction side. Move to draw a loose convex on the enlargement side. The third group (Gr3) moves linearly from the enlargement side to the reduction side.

  In FIGS. 1 to 12, when the lens group is moved during zooming from the telephoto end (T) to the wide-angle end (W), a broken line indicates that the lens group is fixed, and a solid line indicates that the lens group moves. Show. The first group Gr1 is indicated by a one-dot chain line in order to indicate that it does not move during zooming but moves during focusing.

  In the second embodiment (FIG. 2), in zooming from the telephoto end (T) to the wide-angle end (W), the second group (Gr2) and the fifth group (Gr5) are both from the enlargement side to the reduction side. Move to draw a loose convex on the enlargement side. The third group (Gr3) moves linearly from the enlargement side to the reduction side.

  In the third embodiment (FIG. 3), in zooming from the telephoto end (T) to the wide-angle end (W), the second group (Gr2) and the fifth group (Gr5) are both from the enlargement side to the reduction side. Move to draw a loose convex on the enlargement side. The third group (Gr3) moves linearly from the enlargement side to the reduction side.

  In the fourth embodiment (FIG. 4), in zooming from the telephoto end (T) to the wide-angle end (W), the second group (Gr2) and the fifth group (Gr5) are both from the enlargement side to the reduction side. Move to draw a loose convex on the enlargement side. The third group (Gr3) moves linearly from the enlargement side to the reduction side.

  In the fifth embodiment (FIG. 5), in zooming from the telephoto end (T) to the wide-angle end (W), the second group (Gr2) and the fifth group (Gr5) are both from the enlargement side to the reduction side. Move to draw a loose convex on the enlargement side. The third group (Gr3) moves linearly from the enlargement side to the reduction side.

  In the sixth embodiment (FIG. 6), in zooming from the telephoto end (T) to the wide-angle end (W), the second group (Gr2) and the fifth group (Gr5) are both from the enlargement side to the reduction side. Move to draw a loose convex on the enlargement side. The third group (Gr3) moves linearly from the enlargement side to the reduction side.

  In the seventh embodiment (FIG. 7), in zooming from the telephoto end (T) to the wide-angle end (W), the second group (Gr2) and the fifth group (Gr5) are both from the enlargement side to the reduction side. Move to draw a loose convex on the enlargement side. The third group (Gr3) moves linearly from the enlargement side to the reduction side.

  In the eighth embodiment (FIG. 8), in zooming from the telephoto end (T) to the wide-angle end (W), the second group (Gr2) and the fifth group (Gr5) are both from the enlargement side to the reduction side. Move to draw a loose convex on the enlargement side. The third group (Gr3) moves linearly from the enlargement side to the reduction side.

  In the ninth embodiment (FIG. 9), in zooming from the telephoto end (T) to the wide-angle end (W), the second group (Gr2) and the fifth group (Gr5) are both from the enlargement side to the reduction side. Move to draw a loose convex on the enlargement side. The fourth group (Gr4) moves linearly from the enlargement side to the reduction side.

  In the tenth embodiment (FIG. 10), in zooming from the telephoto end (T) to the wide-angle end (W), the second group (Gr2) and the fifth group (Gr5) are both from the enlargement side to the reduction side. Move to draw a loose convex on the enlargement side. The fourth group (Gr4) moves linearly from the enlargement side to the reduction side.

  In the eleventh embodiment (FIG. 11), in zooming from the telephoto end (T) to the wide-angle end (W), the second group (Gr2) linearly moves from the enlargement side to the reduction side, and the third group (Gr3) once moves to the reduction side and then moves again to draw a letter U on the enlargement side, and the fifth group (Gr5) moves from the enlargement side to the reduction side so as to draw a convex on the enlargement side.

  In the twelfth embodiment (FIG. 12), the second group (Gr2), the third group (Gr3), and the fifth group (Gr5) are enlarged in zooming from the telephoto end (T) to the wide-angle end (W). Move from the side to the reduction side. At this time, the second group (Gr2) and the fifth group (Gr5) move so as to draw a loose convex on the enlargement side. The third group (Gr3) moves straight from the enlargement side to the reduction side.

  Hereinafter, the zoom lens according to the present invention will be described more specifically with construction data and the like. In addition, Examples 1 to 12 given here as examples correspond to the first to twelfth embodiments, respectively, and are lens configuration diagrams showing the first to twelfth embodiments (FIGS. 1 to 12). FIG. 12) shows the lens configurations of the corresponding Examples 1 to 12, respectively.

  In the construction data of each example, ri (i = 1, 2, 3,...) Is the radius of curvature (mm) of the i-th surface counted from the enlargement side, and di (i = 1, 2, 3,. ..) Indicates the i-th axis upper surface interval (mm) counted from the enlarged side, and Ni (i = 1, 2, 3,...), Νi (i = 1, 2, 3,...). .) Shows the refractive index (Nd) and Abbe number (νd) for the d-line of the i-th optical element counted from the magnification side. The surface marked with * in the radius of curvature ri indicates that the surface is an aspheric surface, and is defined by the following formula (AS) representing the aspheric surface shape. The last ri in the construction data of each embodiment indicates a mirror surface in the DMD that is a display element, and in each lens configuration diagram, one of a plurality of mirrors is shown as an example.

In the construction data, the distance between the top surfaces of the axes that change during zooming is variable air from the telephoto end (long focal length end, T) to the middle (intermediate focal length state, M) to the wide angle end (short focal length end, W). It is an interval. Total focal length (f, mm) in each focal length state (T), (M), (W), F number (FNO) in focal length state (T) and (W), and aspheric data Is shown together with other data. It should be noted that the projection distance = ∞ for all examples. Further, the F number in each embodiment monotonously changes from the long focal length end (T) to the short focal length end (W).
X (H) = C · H ² / {1+ (1−ε × C ² × H ² ) ^1/2 } + ΣAi × Hi (AS)
However,
X (H): Amount of displacement in the optical axis (AX) direction at the position of height H (based on the surface vertex)
H: Height in a direction perpendicular to the optical axis (AX) C: Paraxial curvature (= 1 / radius of curvature)
ε: quadratic surface parameter Ai: i-th order aspheric coefficient (i = 4, 6, 8, 10)
It is.

  FIGS. 13 to 36 are aberration diagrams corresponding to Examples 1 to 12, respectively. (T) is a telephoto end, and (W) is various aberrations {spherical aberration etc. on the reduction side with respect to an infinite object at a wide angle end. (Mm), astigmatism (mm), distortion (%), lateral chromatic aberration (mm); H: incident height (mm), Y ′: image height (mm)}. In the spherical aberration diagram, the solid line represents the e-line, the one-dot chain line represents the g-line, the two-dot chain line represents the spherical aberration with respect to the C-line, and the broken line represents the sine condition (SC). In the astigmatism diagram, the solid line, the alternate long and short dash line, and the alternate long and two short dashes line represent the astigmatism for the e-line, g-line, and C-line on the sagittal plane (DS), respectively. Astigmatism with respect to e-line, g-line, and C-line on the local surface (DT) is shown. In the lateral chromatic aberration diagram, the solid line represents the lateral chromatic aberration with respect to the g line, and the broken line represents the lateral chromatic aberration with respect to the C line.

  When the zoom lens of each embodiment is used in a projection apparatus (for example, a projector equipped with a DMD), the screen surface (projected surface) is originally an image surface and the display element surface (for example, DMD mirror surface) is an object. In each embodiment, the optical design is a reduction system, and the screen surface is regarded as an object surface, and the optical performance is evaluated on the display element surface.

  Tables 1 and 2 show various values in each example. In addition, Tables 3 to 8 show numerical values corresponding to the conditional expressions (1) to (9) in each example. Table 9 shows numerical values related to the ON / OFF ghost. The conjugate distance shown in Table 9 indicates the distance between the conjugate position at a representative image height having the greatest influence and the DMD mirror surface. In terms of optical design, the conjugate position is determined as a conjugate relationship via the DMD mirror (OFF pixel) surface on which light incident on the zoom lens from the screen surface is condensed and the sixth group lens surface. The conjugate distance shown in Table 9 is the distance between the position having the conjugate relationship and the DMD mirror surface, and it is preferable that this value is large. Table 9 also shows the spot diameters of light that passes through the conjugate position and reaches the DMD mirror again. The larger the spot diameter, the better, and it becomes difficult to confirm the ON / OFF ghost.

Example 1
f = 52.4 (T) to 45.7 (M) to 39.0 (W)
FNO. = 2.71 (T) to 2.50 (W)
Radius of curvature (mm) Spacing between shaft top surfaces (mm) Refractive index (Nd) Abbe number (νd)
r1 96.459
d1 5.868 N1 1.51680 ν1 64.20
r2 -171.002
d2 0.200
r3 59.527
d3 2.001 N2 1.56883 ν2 56.04
r4 28.618
d4 12.055
r5 -44.367
d5 1.600 N3 1.67270 ν3 32.17
r6 69.628
d6 7.226〜9.583〜12.999
r7 -186.445
d7 1.700 N4 1.61293 ν4 36.96
r8 98.478
d8 0.010 N5 1.55000 ν5 47.00
r9 98.478
d9 5.266 N6 1.83400 ν6 37.34
r10 -55.541
d10 0.673 ~ 1.580 ~ 1.625
r11 37.376
d11 4.708 N7 1.83400 ν7 37.34
r12 553.009
d12 12.910 ~ 9.647 ~ 6.186
r13 -103.349
d13 1.201 N8 1.62299 ν8 58.12
r14 38.208
d14 6.813
r15 0.000
d15 3.000-7.321-12.288
r16 51.280
d16 4.548 N9 1.49700 ν9 81.61
r17 -51.280
d17 0.200
r18 34.622
d18 6.474 N10 1.61800 ν10 63.33
r19 -34.622
d19 0.010 N11 1.55000 ν11 47.00
r20 -34.622
d20 1.429 N12 1.64769 ν12 33.84
r21 23.734
d21 10.811
r22 -19.030
d22 1.600 N13 1.80610 ν13 33.27
r23 1925.113
d23 0.010 N14 1.55000 ν14 47.00
r24 1925.113
d24 6.654 N15 1.61800 ν15 63.33
r25 -26.601
d25 0.228
r26 -84.229
d26 4.469 N16 1.49700 ν16 81.61
r27 -32.153
d27 9.588-5.267-0.300
r28 55.250
d28 6.079 N17 1.69895 ν17 30.05
r29 -194.723
d29 10.250
r30 0.000
d30 25.000 N18 1.51680 ν18 64.20
r31 0.000
d31 5.000
r32 0.000
d32 3.000 N19 1.50847 ν19 61.19
r33 0.000
d33 0.500
r34 0.000.

(Example 2)
f = 66.7 (T) to 55.6 (M) to 44.5 (W)
FNO. = 2.75 (T) to 2.50 (W)
Radius of curvature (mm) Spacing between shaft top surfaces (mm) Refractive index (Nd) Abbe number (νd)
r1 154.304
d1 5.261 N1 1.51680 ν1 64.20
r2 -154.30
d2 0.200
r3 137.613
d3 3.691 N2 1.58913 ν2 61.25
r4 40.332
d4 11.074
r5 -48.547
d5 1.900 N3 1.61293 ν3 36.96
r6 98.654
d6 7.963〜11.492〜17.320
r7 -426.334
d7 2.100 N4 1.61293 ν4 36.96
r8 101.878
d8 0.010 N5 1.55000 ν5 47.00
r9 101.878
d9 6.615 N6 1.83400 ν6 37.34
r10 -65.292
d10 8.087〜12.045〜14.524
r11 49.641
d11 5.157 N7 1.67790 ν7 55.52
r12 0.000
d12 20.845-23.358-5.051
r13 -75.374
d13 1.400 N8 1.54814 ν8 45.82
r14 32.366
d14 0.010 N9 1.55000 ν9 47.00
r15 32.366
d15 3.190 N10 1.78472 ν10 25.72
r16 47.276
d16 4.549
r17 0.000
d17 3.000 to 9.004 to 16.269
r18 50.148
d18 5.046 N11 1.49700 ν11 81.61
r19 -68.076
d19 6.942
r20 65.645
d20 5.892 N12 1.61800 ν12 63.33
r21 -65.645
d21 0.010 N13 1.55000 ν13 47.00
r22 -65.645
d22 1.500 N14 1.67270 ν14 32.17
r23 36.517
d23 10.163
r24 -23.485
d24 1.800 N15 1.80610 ν15 33.27
r25 71.004
d25 0.010 N16 1.55000 ν16 47.00
r26 71.004
d26 8.121 N17 1.61800 ν17 63.33
r27 -36.324
d27 0.200
r28 0.000
d28 6.191 N18 1.49700 ν18 81.61
r29 -41.685
d29 13.570-7.565-0.301
r30 76.030
d30 5.505 N19 1.78472 ν19 25.72
r31 -291.206
d31 22.000
r32 0.000
d32 26.000 N20 1.51680 ν20 64.20
r33 0.000
d33 5.000
r34 0.000
d34 3.000 N21 1.50847 ν21 61.19
r35 0.000
d35 0.500
r36 0.000.

(Example 3)
f = 37.7 (T) -33.0 (M) -28.3 (W)
FNO. = 2.69 (T) to 2.50 (W)
Radius of curvature (mm) Spacing between shaft top surfaces (mm) Refractive index (Nd) Abbe number (νd)
r1 115.951
d1 4.500 N1 1.58913 ν1 61.25
r2 36.951
d2 9.201
r3 91.365
d3 4.500 N2 1.52510 ν2 56.38
r4 36.999
d4 22.034
r5 -36.504
d5 3.500 N3 1.58913 ν3 61.25
r6 -58.023
d6 4.115〜6.192〜9.642
r7 -6109.482
d7 2.507 N4 1.67270 ν4 32.17
r8 58.632
d8 0.010 N5 1.55000 ν5 47.00
r9 58.632
d9 14.223 N6 1.74400 ν6 44.90
r10 -73.764
d10 7.353〜17.103〜26.878
r11 100.576
d11 4.482 N7 1.74400 ν7 44.90
r12 -6244.536
d12 46.138〜34.311〜21.086
r13 -55.431
d13 2.000 N8 1.74950 ν8 35.04
r14 27.224
d14 0.010 N9 1.55000 ν9 47.00
r15 27.224
d15 5.391 N10 1.75520 ν10 27.53
r16 -123.179
d16 5.700
r17 0.000
d17 2.000 to 7.471 to 13.643
r18 62.756
d18 5.549 N11 1.49700 ν11 81.61
r19 -71.396
d19 0.200
r20 45.307
d20 7.435 N12 1.61800 ν12 63.33
r21 -46.184
d21 0.010 N13 1.55000 ν13 47.00
r22 -46.184
d22 2.114 N14 1.64769 ν14 33.84
r23 29.544
d23 11.267
r24 -28.229
d24 2.000 N15 1.80610 ν15 33.27
r25 95.920
d25 0.010 N16 1.55000 ν16 47.00
r26 95.920
d26 8.413 N17 1.61800 ν17 63.33
r27 -37.909
d27 0.200
r28 -530.659
d28 5.142 N18 1.49700 ν18 81.61
r29 -52.448
d29 13.642〜8.172〜2.000
r30 60.606
d30 6.355 N19 1.71736 ν19 29.50
r31 -453.009
d31 12.980
r32 0.000
d32 31.000 N20 1.51680 ν20 64.20
r33 0.000
d33 5.000
r34 0.000
d34 3.000 N21 1.50847 ν21 61.19
r35 0.000
d35 0.500
r36 0.000
The aspherical data of the third surface (r3) is shown below.
ε = 1.0000, A4 = 0.296647 × 10 ⁻⁵ , A6 = 0.166687 × 10 ⁻⁹ , A8 = 0.95627 × 10 ⁻¹² , A10 = −0.36131 × 10 ⁻¹⁵ .

Example 4
f = 50.0 (T) to 43.9 (M) to 37.7 (W)
FNO. = 2.70 (T) to 2.50 (W)
Radius of curvature (mm) Spacing between shaft top surfaces (mm) Refractive index (Nd) Abbe number (νd)
r1 50.963
d1 4.500 N1 1.58913 ν1 61.25
r2 35.312
d2 6.346
r3 42.576
d3 4.500 N2 1.52510 ν2 56.38
r4 32.831
d4 17.448
r5 -59.501
d5 2.512 N3 1.64769 ν3 33.84
r6 110.107
d6 11.832 ~ 14.304 ~ 17.974
r7 831.857
d7 7.037 N4 1.80610 ν4 33.27
r8 -65.633
d8 9.643〜12.833〜15.277
r9 54.520
d9 6.097 N5 1.67790 ν5 55.52
r10 -715.052
d10 20.532-14.870-8.756
r11 -74.810
d11 2.399 N6 1.51680 ν6 64.20
r12 73.258
d12 8.301
r13 0.000
d13 2.889-7.944-13.799
r14 52.187
d14 6.637 N7 1.49700 ν7 81.61
r15 -64.502
d15 5.000
r16 50.138
d16 5.467 N8 1.61800 ν8 63.33
r17 -60.529
d17 0.010 N9 1.55000 ν9 47.00
r18 -60.529
d18 2.071 N10 1.67270 ν10 32.17
r19 31.395
d19 10.437
r20 -23.261
d20 2.052 N11 1.80610 ν11 33.27
r21 76.667
d21 0.010 N12 1.55000 ν12 47.00
r22 76.667
d22 8.660 N13 1.61800 ν13 63.33
r23 -35.782
d23 0.200
r24 -1651.609
d24 6.979 N14 1.49700 ν14 81.61
r25 -42.384
d25 12.572〜7.517〜1.662
r26 60.606
d26 5.866 N15 1.78472 ν15 25.72
r27 -1940.579
d27 12.980
r28 0.000
d28 31.000 N16 1.51680 ν16 64.20
r29 0.000
d29 5.000
r30 0.000
d30 3.000 N17 1.50847 ν17 61.19
r31 0.000
d31 0.500
r32 0.000
The aspherical data of the third surface (r3) is shown below.
ε = 1.0000, A4 = 0.14645 × 10 ⁻⁵ , A6 = 0.13269 × 10 ⁻⁸ , A8 = −0.41001 × 10 ⁻¹² , A10 = 0.17606 × 10 ⁻¹⁴ .

(Example 5)
f = 31.3 (T) to 28.5 (M) to 25.6 (W)
FNO. = 1.95 (T) to 1.80 (W)
Radius of curvature (mm) Spacing between shaft top surfaces (mm) Refractive index (Nd) Abbe number (νd)
r1 96.641
d1 6.186 N1 1.51680 ν1 64.20
r2 1315.859
d2 1.168
r3 67.325
d3 2.700 N2 1.58913 ν2 61.25
r4 30.324
d4 11.554
r5 219.346
d5 2.200 N3 1.72342 ν3 37.99
r6 40.538
d6 11.822
r7 -145.593
d7 2.000 N4 1.58913 ν4 61.25
r8 136.525
d8 20.094-23.139-27.162
r9 236.316
d9 4.081 N5 1.83400 ν5 37.34
r10 -98.282
d10 3.212 ~ 2.209 ~ 0.300
r11 47.425
d11 5.241 N6 1.80610 ν6 33.27
r12 871.862
d12 12.129〜10.088〜7.973
r13 -137.761
d13 1.700 N7 1.58144 ν7 40.89
r14 38.568
d14 12.706
r15 0.000
d15 0.500 ~ 5.221 ~ 10.316
r16 54.702
d16 6.601 N8 1.49700 ν8 81.61
r17 -48.277
d17 0.200
r18 62.253
d18 5.973 N9 1.58913 ν9 61.25
r19 -34.498
d19 0.010 N10 1.55000 ν10 47.00
r20 -34.498
d20 1.500 N11 1.80610 ν11 33.27
r21 37.624
d21 9.920
r22 -23.372
d22 1.817 N12 1.80610 ν12 33.27
r23 424.074
d23 0.010 N13 1.55000 ν13 47.00
r24 424.074
d24 6.031 N14 1.58913 ν14 61.25
r25 -37.597
d25 0.200
r26 -183.507
d26 6.035 N15 1.49700 ν15 81.61
r27 -36.544
d27 0.572
r28 159.851
d28 7.819 N16 1.49700 ν16 81.61
r29 -57.230
d29 10.638 to 5.918 to 0.823
r30 58.480
d30 4.861 N17 1.78472 ν17 25.72
r31 178.118
d31 21.317
r32 0.000
d32 25.310 N18 1.51680 ν18 64.20
r33 0.000
d33 5.000
r34 0.000
d34 3.000 N19 1.50847 ν19 61.19
r35 0.000
d35 0.500
r36 0.000.

(Example 6)
f = 44.3 (T) -38.4 (M) -32.7 (W)
FNO. = 2.57 (T) to 2.50 (W)
Radius of curvature (mm) Spacing between shaft top surfaces (mm) Refractive index (Nd) Abbe number (νd)
r1 121.683
d1 3.882 N1 1.51680 ν1 64.20
r2 -98.579
d2 0.200
r3 70.840
d3 1.522 N2 1.51680 ν2 64.20
r4 24.089
d4 9.509
r5 -29.146
d5 1.196 N3 1.58144 ν3 40.89
r6 68.001
d6 2.976-5.328-8.585
r7 483.575
d7 3.229 N4 1.74400 ν4 44.90
r8 -36.480
d8 0.827 ~ 1.376 ~ 0.948
r9 26.719
d9 3.459 N5 1.83400 ν5 37.34
r10 265.659
d10 9.261-6.360-3.431
r11 -84.063
d11 0.902 N6 1.53172 ν6 48.84
r12 26.533
d12 2.009
r13 0.000
d13 2.000-6.110-10.628
r14 26.126
d14 4.057 N7 1.49700 ν7 81.61
r15 -36.940
d15 0.207
r16 213.019
d16 1.094 N8 1.74077 ν8 27.76
r17 24.583
d17 7.245
r18 -14.339
d18 0.934 N9 1.80610 ν9 33.27
r19 43.394
d19 0.010 N10 1.55000 ν10 47.00
r20 43.394
d20 7.657 N11 1.61800 ν11 63.33
r21 -20.895
d21 0.200
r22 139.239
d22 5.613 N12 1.49700 ν12 81.61
r23 -33.958
d23 8.928 ~ 4.818 ~ 0.300
r24 49.836
d24 4.419 N13 1.74077 ν13 27.76
r25 -486.183
d25 10.250
r26 0.000
d26 25.000 N14 1.51680 ν14 64.20
r27 0.000
d27 5.000
r28 0.000
d28 3.000 N15 1.50847 ν15 61.19
r29 0.000
d29 0.500
r30 0.000.

(Example 7)
f = 44.3 (T) -38.4 (M) -32.7 (W)
FNO. = 2.72 (T) to 2.50 (W)
Radius of curvature (mm) Spacing between shaft top surfaces (mm) Refractive index (Nd) Abbe number (νd)
r1 99.389
d1 4.837 N1 1.51680 ν1 64.20
r2 -108.920
d2 0.200
r3 62.477
d3 3.320 N2 1.58913 ν2 61.25
r4 23.789
d4 11.024
r5 -24.642
d5 1.192 N3 1.58144 ν3 40.89
r6 56.281
d6 2.600〜4.285〜6.649
r7 98.551
d7 4.142 N4 1.71300 ν4 53.94
r8 -33.015
d8 0.300 to 0.646 to 0.380
r9 23.677
d9 3.929 N5 1.83400 ν5 37.34
r10 124.078
d10 8.061 ~ 6.029 ~ 3.932
r11 0.000
d11 1.351 N6 1.60342 ν6 38.01
r12 -71.858
d12 0.797
r13 20.191
d13 4.347〜8.841〜14.000
r14 -100.000
d14 3.254 N7 1.49700 ν7 81.61
r15 -19.599
d15 4.642
r16 -16.187
d16 1.392 N8 1.80610 ν8 33.27
r17 51.941
d17 0.010 N9 1.55000 ν9 47.00
r18 51.941
d18 5.944 N10 1.61800 ν10 63.33
r19 -32.860
d19 0.200
r20 -13605.442
d20 6.186 N11 1.49700 ν11 81.61
r21 -24.730
d21 9.954 to 5.460 to 0.300
r22 42.922
d22 4.939 N12 1.62004 ν12 36.29
r23 -318.497
d23 8.959
r24 0.000
d24 25.000 N13 1.51680 ν13 64.20
r25 0.000
d25 5.000
r26 0.000
d26 3.000 N14 1.50847 ν14 61.19
r27 0.000
d27 0.500
r28 0.000.

(Example 8)
f = 44.3 (T) -38.4 (M) -32.7 (W)
FNO. = 2.73 (T) to 2.50 (W)
Radius of curvature (mm) Spacing between shaft top surfaces (mm) Refractive index (Nd) Abbe number (νd)
r1 133.330
d1 1.835 N1 1.58913 ν1 61.25
r2 24.861
d2 4.007
r3 34.882
d3 3.000 N2 1.52510 ν2 56.38
r4 28.817
d4 6.161〜9.985〜15.154
r5 75.592
d5 3.528 N3 1.71300 ν3 53.94
r6 -122.379
d6 5.042 ~ 3.338 ~ 0.300
r7 26.021
d7 4.486 N4 1.74400 ν4 44.90
r8 145.306
d8 13.023〜10.903〜8.772
r9 0.000
d9 2.713
r10 -104.783
d10 0.740 N5 1.68893 ν5 31.16
r11 22.607
d11 3.736-8.342-13.389
r12 -100.255
d12 3.210 N6 1.49700 ν6 81.61
r13 -20.382
d13 3.390
r14 -16.022
d14 2.034 N7 1.71736 ν7 29.50
r15 41.072
d15 0.010 N8 1.55000 ν8 47.00
r16 41.072
d16 7.153 N9 1.61800 ν9 63.33
r17 -38.051
d17 0.200
r18 440.729
d18 6.766 N10 1.49700 ν10 81.61
r19 -28.186
d19 9.953-5.347-0.300
r20 49.016
d20 4.586 N11 1.80518 ν11 25.46
r21 -932.053
d21 9.025
r22 0.000
d22 25.000 N12 1.51680 ν12 64.20
r23 0.000
d23 5.000
r24 0.000
d24 3.000 N13 1.50847 ν13 61.19
r25 0.000
d25 0.500
r26 0.000
The aspherical data of the third surface (r3) is shown below.
ε = 1.0000, A4 = 0.705519 × 10 ⁻⁵ , A6 = 0.78411 × 10 ⁻⁸ , A8 = 0.140303 × 10 ⁻¹¹ , A10 = 0.19146 × 10 ⁻¹³ .

Example 9
f = 31.3 (T) to 28.5 (M) to 25.6 (W)
FNO. = 1.96 (T) to 1.80 (W)
Radius of curvature (mm) Spacing between shaft top surfaces (mm) Refractive index (Nd) Abbe number (νd)
r1 90.791
d1 6.498 N1 1.51680 ν1 64.20
r2 1210.771
d2 0.899
r3 63.891
d3 2.700 N2 1.58913 ν2 61.25
r4 30.174
d4 12.368
r5 458.682
d5 2.200 N3 1.74400 ν3 44.90
r6 44.476
d6 11.134
r7 -172.959
d7 2.000 N4 1.71736 ν4 29.50
r8 120.815
d8 16.881-19.314-22.454
r9 383.954
d9 5.741 N5 1.83400 ν5 37.34
r10 -88.745
d10 1.672
r11 54.199
d11 5.261 N6 1.80610 ν6 33.27
r12 -1187.536
d12 15.628 ~ 13.196 ~ 10.056
r13 -95.206
d13 1.500 N7 1.51680 ν7 64.20
r14 45.769
d14 15.306
r15 0.000
d15 0.560-5.162-9.627
r16 64.724
d16 6.757 N8 1.49700 ν8 81.61
r17 -51.533
d17 1.071 to 0.300 to 0.336
r18 72.563
d18 5.876 N9 1.61800 ν9 63.33
r19 -36.227
d19 0.010 N10 1.55000 ν10 47.00
r20 -36.227
d20 1.500 N11 1.74077 ν11 27.76
r21 40.168
d21 9.305
r22 -25.400
d22 1.800 N12 1.80610 ν12 40.72
r23 112.895
d23 0.010 N13 1.55000 ν13 47.00
r24 112.895
d24 6.654 N14 1.58913 ν14 61.25
r25 -43.133
d25 0.200
r26 -319.516
d26 5.826 N15 1.49700 ν15 81.61
r27 -40.566
d27 0.200
r28 130.811
d28 6.771 N16 1.49700 ν16 81.61
r29 -60.981
d29 8.634 ~ 4.803 ~ 0.302
r30 58.480
d30 4.843 N17 1.78472 ν17 25.72
r31 175.441
d31 21.336
r32 0.000
d32 25.310 N18 1.51680 ν18 64.20
r33 0.000
d33 5.000
r34 0.000
d34 3.000 N19 1.50847 ν19 61.19
r35 0.000
d35 0.500
r36 0.000.

(Example 10)
f = 31.3 (T) to 28.5 (M) to 25.6 (W)
FNO. = 1.99 (T) to 1.80 (W)
Radius of curvature (mm) Spacing between shaft top surfaces (mm) Refractive index (Nd) Abbe number (νd)
r1 85.963
d1 5.889 N1 1.71300 ν1 53.94
r2 377.387
d2 0.200
r3 84.360
d3 2.700 N2 1.62299 ν2 58.12
r4 31.618
d4 10.612
r5 195.181
d5 2.200 N3 1.67790 ν3 55.52
r6 42.551
d6 9.499
r7 -130.189
d7 2.000 N4 1.53172 ν4 48.84
r8 133.796
d8 21.060-23.446-26.124
r9 -2119.542
d9 3.799 N5 1.83400 ν5 37.34
r10 -91.142
d10 11.390
r11 50.274
d11 5.213 N6 1.83400 ν6 37.34
r12 861.854
d12 16.493-14.107-11.429
r13 -120.671
d13 1.500 N7 1.54072 ν7 47.20
r14 43.724
d14 9.386
r15 0.000
d15 1.089 ~ 5.910-10.111
r16 49.944
d16 7.154 N8 1.49700 ν8 81.61
r17 -55.057
d17 0.200
r18 48.493
d18 4.715 N9 1.61800 ν9 63.33
r19 -62.701
d19 0.010 N10 1.55000 ν10 47.00
r20 -62.701
d20 1.500 N11 1.80610 ν11 33.27
r21 34.670
d21 9.092
r22 -22.951
d22 1.800 N12 1.80610 ν12 33.27
r23 107.656
d23 0.010 N13 1.55000 ν13 47.00
r24 107.656
d24 5.551 N14 1.61800 ν14 63.33
r25 -46.782
d25 0.300 to 0.406 to 0.866
r26 -109.315
d26 5.152 N15 1.49700 ν15 81.61
r27 -33.094
d27 0.200
r28 165.469
d28 6.605 N16 1.49700 ν16 81.61
r29 -57.985
d29 9.888 ~ 4.961 ~ 0.300
r30 58.480
d30 6.310 N17 1.78472 ν17 25.72
r31 442.267
d31 19.867
r32 0.000
d32 25.310 N18 1.51680 ν18 64.20
r33 0.000
d33 5.000
r34 0.000
d34 3.000 N19 1.50847 ν19 61.19
r35 0.000
d35 0.500
r36 0.000.

(Example 11)
f = 31.3 (T) to 28.5 (M) to 25.6 (W)
FNO. = 2.32 (T) to 2.20 (W)
Radius of curvature (mm) Spacing between shaft top surfaces (mm) Refractive index (Nd) Abbe number (νd)
r1 99.657
d1 5.466 N1 1.51680 ν1 64.20
r2 3043.121
d2 0.200
r3 62.016
d3 2.600 N2 1.58913 ν2 61.25
r4 29.085
d4 9.399
r5 126.640
d5 2.100 N3 1.67790 ν3 55.52
r6 37.907
d6 15.755
r7 -188.797
d7 1.800 N4 1.71736 ν4 29.50
r8 83.478
d8 16.687 ~ 19.151 ~ 22.096
r9 147.765
d9 4.072 N5 1.80610 ν5 33.27
r10 -92.190
d10 0.200
r11 50.283
d11 4.237 N6 1.83400 ν6 37.34
r12 1970.676
d12 7.129 ~ 3.781 ~ 1.518
r13 240.051
d13 3.178 N7 1.51823 ν7 58.96
r14 -61.492
d14 0.010 N8 1.55000 ν8 47.00
r15 -61.492
d15 1.700 N9 1.72000 ν9 50.34
r16 191.828
d16 3.299 to 4.184 to 3.501
r17 476.272
d17 1.400 N10 1.48749 ν10 70.44
r18 36.801
d18 4.537
r19 0.000
d19 10.524-14.460-19.234
r20 113.477
d20 3.750 N11 1.49700 ν11 81.61
r21 -37.465
d21 0.200
r22 42.707
d22 5.834 N12 1.60300 ν12 65.44
r23 -26.747
d23 0.010 N13 1.55000 ν13 47.00
r24 -26.747
d24 1.200 N14 1.80610 ν14 33.27
r25 31.023
d25 8.875
r26 -19.421
d26 1.700 N15 1.80610 ν15 33.27
r27 0.000
d27 0.010 N16 1.55000 ν16 47.00
r28 0.000
d28 6.629 N17 1.62041 ν17 60.34
r29 -25.574
d29 0.200
r30 240.441
d30 8.089 N18 1.49700 ν18 81.61
r31 -32.094
d31 9.009 ~ 5.074 ~ 0.300
r32 58.480
d32 5.400 N19 1.78472 ν19 25.72
r33 345.249
d33 21.000
r34 0.000
d34 25.310 N20 1.51680 ν20 64.20
r35 0.000
d35 5.000
r36 0.000
d36 3.000 N21 1.50847 ν21 61.19
r37 0.000
d37 0.500
r38 0.000.

(Example 12)
f = 31.3 (T) to 28.5 (M) to 25.6 (W)
FNO. = 1.94 (T) to 1.80 (W)
Radius of curvature (mm) Spacing between shaft top surfaces (mm) Refractive index (Nd) Abbe number (νd)
r1 91.207
d1 6.542 N1 1.51680 ν1 64.20
r2 1572.921
d2 1.081
r3 66.381
d3 3.607 N2 1.62299 ν2 58.12
r4 31.112
d4 11.190
r5 0.000
d5 2.000 N3 1.67790 ν3 55.52
r6 42.841
d6 11.712
r7 -127.012
d7 1.900 N4 1.67790 ν4 55.52
r8 101.222
d8 11.312 ~ 12.882 ~ 15.137
r9 400.835
d9 5.814 N5 1.83400 ν5 37.34
r10 -75.755
d10 8.049-9.363-10.189
r11 51.668
d11 5.476 N6 1.74400 ν6 44.90
r12 -259.678
d12 12.102 ~ 9.218 ~ 6.138
r13 -102.235
d13 1.500 N7 1.51742 ν7 52.15
r14 46.641
d14 11.317
r15 0.000
d15 6.838〜11.488〜16.722
r16 49.900
d16 6.748 N8 1.49700 ν8 81.61
r17 -67.894
d17 1.973
r18 57.334
d18 4.512 N9 1.61800 ν9 63.39
r19 -71.453
d19 0.010 N10 1.55000 ν10 47.00
r20 -71.453
d20 1.400 N11 1.80610 ν11 33.27
r21 36.488
d21 9.464
r22 -23.516
d22 1.700 N12 1.80610 ν12 33.27
r23 141.020
d23 0.010 N13 1.55000 ν13 47.00
r24 141.020
d24 6.174 N14 1.61800 ν14 63.39
r25 -39.171
d25 0.200
r26 -215.827
d26 5.651 N15 1.49700 ν15 81.61
r27 -38.232
d27 0.200
r28 399.485
d28 5.951 N16 1.49700 ν16 81.61
r29 -59.720
d29 10.484〜5.834〜0.600
r30 58.480
d30 5.400 N17 1.78472 ν17 25.72
r31 345.249
d31 20.778
r32 0.000
d32 25.310 N18 1.51680 ν18 64.20
r33 0.000
d33 5.000
r34 0.000
d34 3.000 N19 1.50847 ν19 61.19
r35 0.000
d35 0.500
r36 0.000.

  Various numerical values in each example are shown below.

  Corresponding data and related data of conditional expressions (1) to (9) are shown below.

  The conjugate distance and related data in each example are shown below.

It is sectional drawing which shows the structure of the zoom lens of 1st Embodiment. It is sectional drawing which shows the structure of the zoom lens of 2nd Embodiment. It is sectional drawing which shows the structure of the zoom lens of 3rd Embodiment. It is sectional drawing which shows the structure of the zoom lens of 4th Embodiment. It is sectional drawing which shows the structure of the zoom lens of 5th Embodiment. It is sectional drawing which shows the structure of the zoom lens of 6th Embodiment. It is sectional drawing which shows the structure of the zoom lens of 7th Embodiment. It is sectional drawing which shows the structure of the zoom lens of 8th Embodiment. It is sectional drawing which shows the structure of the zoom lens of 9th Embodiment. It is sectional drawing which shows the structure of the zoom lens of 10th Embodiment. It is sectional drawing which shows the structure of the zoom lens of 11th Embodiment. It is sectional drawing which shows the structure of the zoom lens of 12th Embodiment. FIG. 3 is an aberration diagram at Example 1 at a telephoto end. FIG. 3 is an aberration diagram at Example 1 at the wide-angle end. FIG. 6 is an aberration diagram at Example 2 at a telephoto end. FIG. 5 is an aberration diagram at Example 2 at the wide-angle end. FIG. 6 is an aberration diagram at Example 3 at the telephoto end. FIG. 6 is an aberration diagram at Example 3 at the wide-angle end. FIG. 6 is an aberration diagram at Example 1 at the telephoto end. FIG. 6 is an aberration diagram at Example 4 at the wide-angle end. FIG. 12 is an aberration diagram at Example 5 at a telephoto end. FIG. 6 is an aberration diagram at Example 5 at the wide-angle end. FIG. 10 is an aberration diagram at Example 10 at the telephoto end. FIG. 6 is an aberration diagram at Example 6 at the wide-angle end. FIG. 10 is an aberration diagram at Example 10 at the telephoto end. FIG. 10 is an aberration diagram at Example 7 at the wide-angle end. FIG. 10 shows aberration diagrams at the telephoto end of Example 8. FIG. 10 shows aberration diagrams at the wide-angle end of Example 8. FIG. 10 shows aberration diagrams at the telephoto end of Example 9. FIG. 10 shows aberration diagrams at the wide-angle end of Example 9. FIG. 12 shows aberration diagrams at the telephoto end of Example 10. FIG. 10 is an aberration diagram at Example 10 at the wide-angle end. FIG. 12 shows aberration diagrams at the telephoto end of Example 11. FIG. 14 is an aberration diagram at Example 11 at the wide-angle end. FIG. 12 is an aberration diagram at Example 12 at the telephoto end. FIG. 12 shows aberration diagrams at the wide-angle end of Example 12. It is a figure explaining ON / OFF ghost.

Explanation of symbols

AX Optical axis Gr1 1st group Gr2 2nd group Gr3 3rd group Gr4 4th group Gr5 5th group Gr6 6th group ST Aperture P1 Prism P2 Parallel plate 50 DMD (Display element)

Claims (6)

In the zoom lens composed of six groups, the first group to the sixth group in order from the magnification side for enlarging and projecting the display element,
A first group having a negative refractive power; a second group that moves when zooming with a positive refractive power; a fifth group that moves when zooming with a positive refractive power; a sixth group having a positive refractive power; With
Furthermore, the third group that moves at the time of zooming with positive or negative refractive power and the fourth group with negative refractive power having a stop, or the third group with negative refractive power that has a stop and positive or negative Any one of the fourth group moving at the time of zooming with refractive power,
The sixth group consists of one positive lens, and satisfies the following conditional expression:
1.35 ≦ Bf / CR1 × F ≦ 2.00
However,
Bf: distance on the optical axis from the center of the lens surface on the reduction side of the positive lens in the sixth group to the display element surface arranged perpendicular to the optical axis CR1: curvature on the enlargement side of the positive lens in the sixth group Radius F: Minimum F value of zoom lens
And
When the third group has a negative refractive power and a stop and the fourth group moves at the time of zooming with a positive or negative refractive power, among the positive lenses constituting the fourth group and the fifth group At least one of the positive lenses constituting the fifth group when the fourth group has a negative refractive power and a stop and the third group moves at the time of zooming with a positive or negative refractive power At least one sheet is made of a material that satisfies the following conditional expression:
nd> 1.58
νd> 59
However,
nd: refractive index with respect to d-line (wavelength 587.56 nm) νd: Abbe number with respect to d-line (wavelength 587.56 nm)
And
Furthermore, the following conditional expression is satisfied ,
1.70 ≦ fxw / fw ≦ 4.80
However,
fxw: the fourth group and the fifth group when the zoom lens is at the wide-angle end when the third group has a negative refractive power and a stop and the fourth group moves with a positive or negative refractive power upon zooming When the fourth group has a negative refractive power and a stop and the third group moves at the time of zooming with a positive or negative refractive power, the focal length fw of the fifth group: a zoom lens Focal length with wide angle end
And
The zoom lens according to claim 6, wherein the positive lens in the sixth group satisfies the following conditional expression.
−1 / 3 ≦ CR1 / CR2 ≦ 1/3
However,
CR1: Radius of curvature on the enlargement side of the sixth lens group positive lens
CR2: radius of curvature of the sixth group positive lens on the display element side
It is. The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
1.70 ≦ fxt / ft ≦ 3.70
However,
fxt: the fourth group and the fifth group when the zoom lens is at the telephoto end when the third group has a negative refracting power and a stop and the fourth group moves at the time of zooming with a positive or negative refracting power The composite focal length, consisting of
When the fourth group has a negative refractive power and a stop and the third group moves at the time of zooming with a positive or negative refractive power, the focal length of the fifth group ft: the focal point when the zoom lens is at the telephoto end distance The zoom lens according to claim 1, wherein the positive lens in the sixth group is made of a material that satisfies the following conditional expression.
nd> 1.60
However,
nd: refractive index for d-line (wavelength 587.56 nm) The zoom lens according to claim 1, wherein the positive lens in the sixth group is made of a material that satisfies the following conditional expression.
nd> 1.68
However,
nd: refractive index for d-line (wavelength 587.56 nm) The sixth group of the positive lens, the zoom lens according to any one of claims 1 to 4, characterized in that the following conditional expression is satisfied.
0.75 ≦ Bf / f6 × F ≦ 1.60
However,
Bf: distance on the optical axis from the center of the lens surface on the reduction side of the positive lens in the sixth group to the display element surface arranged perpendicular to the optical axis f6: focal length of the sixth group F: zoom lens Minimum F value The display element is a zoom lens according to any one of claims 1 to 5, characterized in that a DMD.

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