JP6007589B2 - Projection zoom lens and image display device - Google Patents

Description

  The present invention relates to a projection zoom lens used in a projection optical system of a projector apparatus, and is particularly suitable for enlarging and projecting an original image formed by a light beam light-modulated by a micro device onto a screen. The present invention relates to a zoom lens and an image display device equipped with the zoom lens.

  A front projection type projector device that projects an image on a projection surface (screen) installed in front of the device is widely used for presentations in schools, for school education, and for home use. Most of light modulation elements (light valves) used in projector apparatuses are transmissive or reflective liquid crystal elements, but in recent years, digital micromirror devices (Digital Micromirror Device: DMD) are advantageous for miniaturization and high brightness. The number of devices using micro devices represented by

  The DMD is a reflective image display element that generates and displays a projected image by light reflected by a micromirror. The turning angle of the micromirror is about ± 10 degrees, and effective reflection light and invalid reflection light can be switched by the difference in angle. A projection lens of a projector device using DMD needs to be able to effectively limit the incidence of effective reflected light and invalid reflected light from DMD. For this reason, it is desirable to arrange the projection lens in the normal direction on the DMD side, but in order to achieve such an arrangement, the illumination light source is arranged at a position substantially equivalent to the projection lens. As described above, there is a positional limitation in arranging the projection lens in the normal direction on the DMD side.

  Considering the above constraints, the projection lens of the projector device adopting the DMD needs to be small so that the lens diameter on the light valve side does not interfere with the illumination optical system, and the back focus must be long. I must. For this reason, a relatively low-magnification zoom lens and a telephoto zoom lens are suitable for the projection lens of the projector apparatus employing the DMD.

  In recent years, in such a projection lens, a lens obtained by multiplying a high-magnification zoom and a wide-angle zoom has been demanded, and projection lenses that can cope with this are also known (for example, Patent Documents 1, 2, 3, and 4). reference).

  The lenses of Patent Document 1 and Patent Document 2 are projection zoom lenses aiming at higher magnification in the 5th group and the 6th group, and have a zoom ratio of about x1.5. Although the aberration is sufficiently suppressed, the half angle of view ω is 30 °. The lenses of Patent Document 3 and Patent Document 4 are wide-angle zoom lenses of a projection optical system, but are LCD type telecentric optical systems and cannot be adapted to an optical system using DMD. As described above, in the conventionally known projection zoom lens, it is difficult to achieve both a high magnification and a wide angle of view in the projection lens of the projector apparatus adopting the DMD.

  The present invention has been made in view of the above problems, and is a lens suitable for a projector apparatus that employs an image display element such as a DMD as a light modulation element, and has a wider half-field angle (ω = 39 to It is an object of the present invention to provide a high-performance projection zoom lens that is 45 °) and has a high magnification x1.5 zoom ratio.

The present invention relates to a projection zoom lens that constitutes a projection optical system of an image display device that projects an image displayed on a display surface of an image display element onto a projection surface and displays the enlarged image. Arranged from the side toward the image display element side,
A first lens group having negative refractive power;
A second lens group having negative refractive power;
A third lens group having positive refractive power;
A fourth lens group having a positive refractive power;
A fifth lens group having negative refractive power;
Consists of
When zooming from the wide-angle side to the telephoto side,
The first lens group is fixed, and the second lens group, the third lens group, the fourth lens group, and the fifth lens group move so that the distance between the adjacent lens groups changes,
The focal length of the negative lens closest to the image display element in the fifth lens group is F5n,
The focal length of the positive lens closest to the image display element in the fifth lens group is F5p,
When
-1.9 <F5n / F5p <-1.1
Satisfying the above is the main feature.

  According to the present invention, it is possible to obtain a projection zoom lens and an image display device having a wide angle of view and a high magnification.

FIG. 2 is an optical arrangement diagram showing a wide-angle end (a) and a telephoto end (b) according to an embodiment of the zoom lens for projection according to the present invention. FIG. 2A is a (a) spherical aberration diagram, (b) an astigmatism diagram, and (c) a distortion diagram at the wide angle end according to Example 1 of the projection zoom lens. FIG. 4 is an intermediate (a) spherical aberration diagram, (b) astigmatism diagram, and (c) distortion diagram according to Example 1 of the projection zoom lens. FIG. 3A is a spherical aberration diagram, FIG. 5B is an astigmatism diagram, and FIG. 3C is a distortion diagram at the telephoto end according to Example 1 of the projection zoom lens. FIG. 5 is an optical arrangement diagram showing a wide-angle end (a) and a telephoto end (b) according to Example 2, which is an embodiment of the projection zoom lens according to the present invention. FIG. 5A is a diagram illustrating (a) spherical aberration, (b) astigmatism, and (c) distortion diagrams at the wide angle end according to Example 2 of the projection zoom lens. FIG. 6A is an intermediate (a) spherical aberration diagram, (b) astigmatism diagram, and (c) distortion aberration diagram according to Example 2 of the projection zoom lens. (A) Spherical aberration diagram, (b) Astigmatism diagram, and (c) Distortion diagram at the telephoto end according to Example 2 of the projection zoom lens. FIG. 5 is an optical arrangement diagram showing a wide-angle end (a) and a telephoto end (b) according to Example 3, which is an embodiment of a projection zoom lens according to the present invention. FIG. 4A is a (a) spherical aberration diagram, (b) an astigmatism diagram, and (c) a distortion aberration diagram at a wide angle end according to Example 3 of the projection zoom lens. FIG. 5A is an intermediate (a) spherical aberration diagram, (b) astigmatism diagram, and (c) distortion diagram according to Example 3 of the projection zoom lens. (A) Spherical aberration diagram, (b) Astigmatism diagram, (c) Distortion diagram at the telephoto end according to Example 3 of the projection zoom lens. FIG. 5 is an optical arrangement diagram showing a wide-angle end (a) and a telephoto end (b) according to Example 4 which is an embodiment of the projection zoom lens according to the present invention. (A) Spherical aberration diagram, (b) Astigmatism diagram, and (c) Distortion diagram at the wide angle end of Example 4 of the projection zoom lens. FIG. 5A is an intermediate (a) spherical aberration diagram, (b) astigmatism diagram, and (c) distortion aberration diagram according to Example 4 of the projection zoom lens. (A) Spherical aberration diagram, (b) Astigmatism diagram, and (c) Distortion diagram at the telephoto end according to Example 4 of the projection zoom lens. FIG. 9 is an optical arrangement diagram showing a wide-angle end (a) and a telephoto end (b) according to Example 5 which is an embodiment of the projection zoom lens according to the present invention. (A) Spherical aberration diagram, (b) Astigmatism diagram, and (c) Distortion diagram at the wide angle end according to Example 5 of the projection zoom lens. FIG. 6A is an intermediate (a) spherical aberration diagram, (b) astigmatism diagram, and (c) distortion aberration diagram according to Example 5 of the projection zoom lens. (A) Spherical aberration diagram, (b) Astigmatism diagram, and (c) Distortion diagram at the telephoto end according to Example 5 of the projection zoom lens. FIG. 10 is an optical arrangement diagram showing a wide-angle end (a) and a telephoto end (b) according to Example 6 which is an embodiment of the projection zoom lens according to the present invention. (A) Spherical aberration diagram, (b) Astigmatism diagram, and (c) Distortion diagram at the wide angle end according to Example 6 of the projection zoom lens. FIG. 10A is an intermediate (a) spherical aberration diagram, (b) astigmatism diagram, and (c) distortion diagram according to Example 6 of the projection zoom lens. (A) Spherical aberration diagram, (b) Astigmatism diagram, and (c) Distortion diagram at the telephoto end according to Example 6 of the projection zoom lens. FIG. 10 is an optical arrangement diagram showing a wide-angle end (a) and a telephoto end (b) according to Example 7, which is an embodiment of the projection zoom lens according to the present invention. (A) Spherical aberration diagram, (b) Astigmatism diagram, and (c) Distortion diagram at the wide angle end according to Example 7 of the projection zoom lens. FIG. 8A is an intermediate (a) spherical aberration diagram, (b) astigmatism diagram, and (c) distortion diagram according to Example 7 of the projection zoom lens. (A) Spherical aberration diagram, (b) Astigmatism diagram, and (c) Distortion diagram at the telephoto end according to Example 7 of the projection zoom lens. It is a schematic structure figure showing an example of an embodiment of an image display device concerning the present invention.

Embodiments of a projection zoom lens and an image display device according to the present invention will be described below with reference to the drawings. In the present specification, the unit of the focal length is mm.

● Projection zoom lens ●
First Embodiment Hereinafter, an embodiment of a projection zoom lens according to the present invention will be described. The projection zoom lens according to the present embodiment is a projection zoom lens suitable for an image display device (projector device) using a reflective image display element such as a DMD as a light modulation element, and has a lens group configuration on the enlargement side. It has an arrangement having negative, negative, positive, positive, and negative refractive power from the (projected surface side), and satisfies the following conditional expression 1.
(Condition 1) -1.9 <F5n / F5p <-1.1
Here, F5n represents the focal length of the negative lens closest to the reduction side (image display element side) of the fifth lens group, and F5p represents the focal length of the positive lens closest to the reduction side (image display element side) of the fifth lens group.

  If the upper limit of conditional expression 1 is exceeded, spherical aberration is corrected, the astigmatism difference increases, and field curvature also increases, which is not desirable. Further, if the lower limit of conditional expression 1 is exceeded, the telephoto side field curvature and astigmatic difference are greatly generated, which is not desirable.

Second Embodiment The projection zoom lens according to the second embodiment provides an optimal solution for the configuration of the fifth lens group in the projection zoom lens according to the first embodiment. That is, the lenses constituting the fifth lens group are lenses having negative-positive-negative-positive refractive power in order from the magnification side (projection surface side). In particular, by using the most magnified negative lens and positive lens in the fifth lens group as a cemented lens, an effective achromatic effect can be provided at the wide-angle end, the telephoto end, and zooming.

  Note that the effect of the present embodiment is exhibited even if the lens on the most magnified side of the fifth group is not a cemented lens of lenses having negative-positive refractive power. That is, even if it is not a cemented lens, the achromatic effect can be sufficiently maintained. When a lens having a negative-positive refractive power is arranged as a single unit, the assembly sensitivity increases when the lens is decentered in the direction perpendicular to the optical axis direction of the lens. Although it is desirable, it is not necessary to use a cemented lens as long as an assembly error can be maintained.

  The single negative lens arranged third from the enlargement side of the fifth lens group has the effect of generating large positive spherical aberration and flattening the projection surface. If the configuration of the fifth lens group is “negative-positive-positive”, these relationships are lost, and various aberrations are insufficiently corrected in terms of optical performance. The single lens on the most reduction side is an indispensable lens because it has the effect of adjusting coma and spherical aberration.

  Note that the present embodiment is also established when the lenses constituting the fifth lens group are “negative-positive-positive-negative” or “negative-positive-positive” in order from the magnification side. However, the coma aberration is less balanced at the wide-angle end (Wide end) and the enlargement end (Tele end) than the “negative-positive-negative-positive” configuration, and the performance is inferior.

Third Embodiment A projection zoom lens according to the third embodiment provides an optimal solution related to the focal length of the fifth lens group in the projection zoom lens according to the first and second embodiments. . That is, according to the projection zoom lens according to this embodiment, the projection zoom lens according to the first and second embodiments satisfies the following conditional expression 2.
(Condition 2) -0.01 <1 / F5
Here, F5 represents the focal length of the fifth lens group. Conditional expression 2 is a conditional expression for obtaining an optimal solution related to the refractive power of the fifth lens group. In particular, an optimal solution for spherical aberration and coma aberration can be obtained, and when the upper limit or lower limit of conditional expression 2 is exceeded, the power of the fifth lens group becomes strong, so that the power arrangement condition collapses, and spherical aberration and coma Aberration tends to increase, which is not desirable.

Fourth Embodiment A projection zoom lens according to the fourth embodiment is the same as the projection zoom lens according to the first to third embodiments, except that the focal length of the third lens group and the fourth lens group are the same. Provides an optimal solution for focal length. That is, according to the projection zoom lens according to the present embodiment, the projection zoom lens according to the first to third embodiments satisfies the following conditional expression 3.
(Condition 3) 1.3 <F3 / F4 <4.6
However, F3 represents the focal length of the third lens group, and F4 represents the focal length of the fourth lens group. Conditional expression 3 is a conditional expression for deriving an optimal solution for chromatic aberration correction during zooming. If the upper limit or lower limit of conditional expression 3 is exceeded, chromatic aberration is overcorrected and affects resolution performance. Not desirable.

Fifth Embodiment In addition, the projection zoom lens according to the fifth embodiment provides an optimal solution regarding the focal length of the second lens group in the projection zoom lens according to the first to fourth embodiments. . That is, according to the projection zoom lens according to the present embodiment, the projection zoom lens according to the first to fourth embodiments satisfies the following conditional expression 4.
(Condition 4) −0.27 <Fw / F2 <−0.11
However, Fw represents the focal length at the wide-angle end of the entire optical system, and F2 represents the focal length of the second lens group. If the upper limit of Conditional Expression 4 is exceeded, that is, if the refractive power of the second lens group is small, the lateral chromatic aberration is large, which is not desirable. Further, when the lower limit of conditional expression 4 is exceeded, that is, when the refractive power of the second lens group becomes large, various aberrations are overcorrected, which is undesirable because it adversely affects the resolution performance.

Sixth Embodiment In addition, the projection zoom lens according to the sixth embodiment provides an optimal solution related to the pupil position and the image height in the projection zoom lenses according to the first to fifth embodiments. That is, according to the projection zoom lens according to the present embodiment, the projection zoom lens according to the first to fifth embodiments satisfies the following conditional expression 5.
(Condition 5) 4.0 <| EPw / DMDHT | <4.5
Where EPw is the distance from the DMD surface to the entrance pupil at the wide-angle end, and DMDHT is the distance from the rotation center axis of the spherical lens closest to the DMD to the reduction side to the outermost periphery of the DMD. Conditional expression 5 is a structural conditional expression, and the ratio of EPw and DMDHT is preferably within the numerical range shown in conditional expression 5. Exceeding the upper limit or lower limit of Conditional Expression 5 is not desirable because it affects the resolution performance as a result of increasing the size of the entire optical system, increasing the light incident angle, and the like.

Seventh Embodiment In addition, the projection zoom lens according to the seventh embodiment is the same as the projection zoom lens according to the first to sixth embodiments, but the optimal solution regarding the focal length and back focus of the entire optical system. I will provide a. That is, according to the projection zoom lens according to the present embodiment, the projection zoom lens according to the first to sixth embodiments satisfies the following conditional expression 6.
(Condition 6) 0.35 <Fw / BFw <0.45
However, BFw represents the distance from the reduction-side surface of the lens on the most reduction side at the wide-angle end to the DMD surface, and Fw represents the focal length at the wide-angle end of the entire optical system. Conditional expression 6 is a structural conditional expression, and the ratio of FW and BFw is preferably within the numerical range shown in conditional expression 6. Exceeding the upper limit or lower limit of conditional expression 6 is not desirable because it affects the image performance as a result of increasing the size of the entire optical system, increasing the light incident angle, and the like.

Eighth Embodiment A projection zoom lens according to the eighth embodiment is a half-image when the zoom ratio is x1.5 in the projection zoom lens according to the first to seventh embodiments. Provides an optimal solution for the angle ω. According to the projection zoom lens according to the present embodiment, the following conditional expression 7 is satisfied in the first to seventh embodiments.
(Condition 7) 39 <ω <45
However, ω represents a half angle of view.

Ninth Embodiment The ninth embodiment provides an image display device having the projection zoom lens according to the first to eighth embodiments.

Examples Next, specific examples of the projection zoom lens according to the present invention will be described. Aberrations in each example are corrected at a high level, and spherical aberration, astigmatism, curvature of field, axial chromatic aberration, and distortion are sufficiently corrected, and maintaining good optical performance is as follows. It is clear from the numerical value shown in.

Symbols in each example are as follows.
F: Focal length of the entire optical system (mm)
Fno: Numerical aperture ω: Half angle of view R: Radius of curvature D: Surface interval Nd: Refractive index νd: Abbe number L: Lens G: Lens group The aspherical surface is represented by the following conditions.
X = (H2 / R) / [1+ {1-k (H / R) 2} 1/2] + C4H4 + C6H6 + C8H8 + C10H10 +.

  In the optical arrangement diagrams of the projection zoom lens of each embodiment shown below, the rotation center axis of the spherical lens closest to the DMD is indicated by a one-dot chain line. The “rotation center axis of the spherical lens closest to the DMD” and the rotation center axes of all the other spherical lenses except for the lens L12 and the lens L54 coincide with each other, and this rotation center axis becomes the reference axis of the projection optical system. ing. It should be noted that the rotation center axes of all spherical lenses are not necessarily coincident.

  1A and 1B are optical arrangement diagrams of a projection zoom lens according to Example 1. FIG. 1A shows a wide-angle end, and FIG. 1B shows a telephoto end. In the projection zoom lens according to Example 1, in order from the enlargement side, the first lens group G1 includes lenses L11 to L13, the second lens group G2 includes lenses L21 to L24, and a third lens group. G3 includes a lens L31, the fourth lens group G4 includes lenses L41 to L42, and the fifth lens group G5 includes lenses L51 to L54. On the reduction side, a DMD (digital micromirror device) as a light modulation element is arranged. A cover glass (CG) (not shown) is disposed on the DMD surface facing the lens.

  In the projection zoom lens according to Example 1, when zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves to the reduction side, and the third lens group G3 expands. The fourth lens group G4 moves to the enlargement side, and the fifth lens group G5 moves to the enlargement side. Thus, zooming (magnification) from the wide-angle end to the telephoto end can be performed. The third lens group G3, the fourth lens group G4, and the fifth lens group G5 move at different timings.

  The first lens group G1 is a negative group, and includes a negative negative lens L11 on the reduction side, a negative negative lens L12 on the enlargement side, and a negative negative lens L13 on the reduction side.

  The second lens group G2 is a negative group, and includes a double-sided positive lens L21, a double-sided negative lens L22, a convex lens L23 on the reduction side, and a concave negative lens L24 on the enlargement side, and the lens L23 and the lens L24. Are joined.

  The third lens group G3 is a positive group, and includes a double-sided positive lens L31.

  The fourth lens group G4 is a positive group, and includes a positive lens L41 having a convex surface on the magnifying side and a positive lens L42 having a convex surface on the magnifying side.

  The fifth lens group G5 is a negative group, and includes a convex negative lens L51 on the magnifying side, a double-sided positive lens L52, a concave negative lens L53 on the magnifying side, and a double-sided positive lens L54. L52 is joined.

  FIGS. 2 to 4 show aberration diagrams of the projection zoom lens according to Example 1. FIG. 2 is a wide-angle end, FIG. 3 is an intermediate end, and FIG. 4 is a telephoto end. Indicates spherical aberration, (b) indicates astigmatism, and (c) indicates distortion. In the spherical aberration (a) in each figure, the symbol R indicates red (wavelength is 625 nm), the symbol G indicates green (wavelength is 550 nm), and the symbol B indicates blue (wavelength is 460 nm). In each figure, astigmatism (b), symbol S indicates the sagittal image plane, and symbol T indicates the astigmatism of the tangential image plane. As shown in FIGS. 2 to 4, the aberration correction is in a good state at each zoom position.

なお、表１中の「ＩＮＦ」は無限大を表す。表１中のアスタリスク（＊）は非球面であることを表し、その非球面係数の数値は表２に示す通りである。また、表１中のＳ６、Ｓ１３、Ｓ１５、Ｓ２０はズーミングした際に、下記の表３に示すように変化する。なお、投射距離は１６００ｍｍ時のレンズ間隔である。また、上記に示した各条件式に係る数値は、表４に示す通りである。 Each numerical value of Example 1 is shown in Table 1.

Note that “INF” in Table 1 represents infinity. An asterisk (*) in Table 1 represents an aspheric surface, and the numerical value of the aspheric coefficient is as shown in Table 2. Further, S6, S13, S15, and S20 in Table 1 change as shown in Table 3 below when zooming. The projection distance is a lens interval at 1600 mm. Further, numerical values relating to the conditional expressions shown above are as shown in Table 4.

  FIGS. 5A and 5B are optical arrangement diagrams of the projection zoom lens according to Example 2. FIG. 5A shows the wide-angle end, and FIG. 5B shows the telephoto end. In the zoom lens for projection according to Example 2, in order from the magnification side, the first lens group G1 includes lenses L11 to L13, the second lens group G2 includes lenses L21 to L24, and a third lens group. G3 includes a lens L31, the fourth lens group G4 includes lenses L41 to L42, and the fifth lens group G5 includes lenses L51 to L54. A DMD (digital micromirror device) as a light modulation element is disposed on the reduction end side. A cover glass (CG) (not shown) is disposed on the DMD surface facing the lens.

  In the projection zoom lens according to Example 2, when zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves to the reduction side, and the third lens group G3 expands. The fourth lens group G4 moves to the enlargement side, and the fifth lens group G5 moves to the enlargement side. Thus, zooming (magnification) from the wide-angle end to the telephoto end can be performed. The third lens group G3, the fourth lens group G4, and the fifth lens group G5 move at different timings.

  The first lens group G1 is a negative group, and includes a negative negative lens L11 on the reduction side, a negative negative lens L12 on the enlargement side, and a negative negative lens L13 on the reduction side.

  The second lens group G2 is a negative group, and includes a double-convex positive lens L21, a double-sided concave negative lens L22, a convex side L23 on the reduction side, and a negative negative lens L24 on the enlargement side. The lens L23 and the lens L24 are It is joined.

  The third lens group G3 is a positive group, and includes a double-sided positive lens L31.

  The fourth lens group G4 is a positive group, and includes a positive lens L41 having a convex surface on the magnifying side and a positive lens L42 having a convex surface on the magnifying side.

  The fifth lens group G5 is a negative group, and includes a convex negative lens L51 on the magnifying side, a double-sided positive lens L52, a concave negative lens L53 on the magnifying side, and a double-sided positive lens L54. L52 is joined.

  FIGS. 6 to 8 show aberration diagrams of the projection zoom lens according to Example 2. FIG. 6 shows the wide-angle end, FIG. 7 shows the middle, and FIG. 8 shows the telephoto end. Indicates spherical aberration, (b) indicates astigmatism, and (c) indicates distortion. In the spherical aberration (a) in each figure, the symbol R indicates red (wavelength is 625 nm), the symbol G indicates green (wavelength is 550 nm), and the symbol B indicates blue (wavelength is 460 nm). In each figure, astigmatism (b), symbol S indicates the sagittal image plane, and symbol T indicates the astigmatism of the tangential image plane. As shown in FIGS. 6 to 8, the aberration correction is in a good state at each zoom position.

なお、表中の「ＩＮＦ」は無限大を表す。表５中のアスタリスク（＊）は非球面であることを表し、その非球面係数の数値は表６に示す通りである。また、表５中のＳ６、Ｓ１３、Ｓ１５、Ｓ２０はズーミングした際に、下記の表７に示すように変化する。なお、投射距離は１６００ｍｍ時のレンズ間隔である。また、上記に示した各条件式に係る数値は、表８に示す通りである。 Each numerical value of Example 2 is shown in Table 5.

Note that “INF” in the table represents infinity. An asterisk (*) in Table 5 represents an aspheric surface, and the numerical value of the aspheric coefficient is as shown in Table 6. Also, S6, S13, S15, and S20 in Table 5 change as shown in Table 7 below when zooming. The projection distance is a lens interval at 1600 mm. Further, numerical values relating to the conditional expressions shown above are as shown in Table 8.

  FIG. 9 shows an optical arrangement of the projection zoom lens according to Example 3, where (a) shows the wide-angle end and (b) shows the telephoto end. In the zoom lens for projection according to Example 3, in order from the enlargement side, the first lens group G1 includes lenses L11 to L13, the second lens group G2 includes lenses L21 to L24, and a third lens group. G3 includes a lens L31, the fourth lens group G4 includes lenses L41 to L42, and the fifth lens group G5 includes lenses L51 to L54. A DMD (digital micromirror device) as a light modulation element is disposed on the reduction end side. A cover glass (CG) (not shown) is disposed on the DMD surface facing the lens.

  In the projection zoom lens according to Example 4, when zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 is moved to the reduction side, and the third lens group G3 is enlarged. The fourth lens group G4 moves to the enlargement side, and the fifth lens group G5 moves to the enlargement side. Thus, zooming (magnification) from the wide-angle end to the telephoto end can be performed. The third lens group G3, the fourth lens group G4, and the fifth lens group G5 move at different timings.

  The first lens group G1 is a negative group, and includes a negative negative lens L11 on the reduction side, a negative negative lens L12 on the enlargement side, and a negative negative lens L13 on the reduction side.

  The second lens group G2 is a negative group, and includes a double-convex positive lens L21, a double-sided concave negative lens L22, a convex side L23 on the reduction side, and a negative negative lens L24 on the enlargement side. The lens L23 and the lens L24 are It is joined.

  The third lens group G3 is a positive group, and includes a double-sided positive lens L31.

  The fourth lens group G4 is a positive group, and includes a positive lens L41 having a convex surface on the magnifying side and a positive lens L42 having a convex surface on the magnifying side.

  The fifth lens group G5 is a negative group, and includes a convex negative lens L51 on the magnifying side, a double-sided positive lens L52, a concave negative lens L53 on the magnifying side, and a double-sided positive lens L54. L52 is joined.

  FIGS. 10 to 12 show aberration diagrams of the projection zoom lens according to Example 3. FIG. 10 shows the wide-angle end, FIG. 11 shows the middle, and FIG. 12 shows the telephoto end. Indicates spherical aberration, (b) indicates astigmatism, and (c) indicates distortion. In the spherical aberration (a) in each figure, the symbol R indicates red (wavelength is 625 nm), the symbol G indicates green (wavelength is 550 nm), and the symbol B indicates blue (wavelength is 460 nm). In each figure, astigmatism (b), symbol S indicates the sagittal image plane, and symbol T indicates the astigmatism of the tangential image plane. As shown in FIGS. 10 to 12, the aberration correction is in a good state at each zoom position.

なお、表９中の「ＩＮＦ」は無限大を表す。表９中のアスタリスク（＊）は非球面であることを表し、その非球面係数の数値は表１０に示す通りである。また、表９中のＳ６、Ｓ１３、Ｓ１５、Ｓ２０はズーミングした際に、下記の表１１に示すように変化する。なお、投射距離が１６００ｍｍ時のレンズ間隔である。また、上記に示した各条件式に係る数値は、表１２に示す通りである。 Table 9 shows numerical values of Example 3.

Note that “INF” in Table 9 represents infinity. An asterisk (*) in Table 9 represents an aspheric surface, and the numerical value of the aspheric coefficient is as shown in Table 10. Further, S6, S13, S15, and S20 in Table 9 change as shown in Table 11 below when zooming. Note that this is the lens interval when the projection distance is 1600 mm. Further, numerical values relating to the conditional expressions shown above are as shown in Table 12.

  FIGS. 13A and 13B are optical arrangement diagrams of the projection zoom lens according to Example 4. FIG. 13A shows the wide-angle end, and FIG. 13B shows the telephoto end. In the zoom lens for projection according to Example 4, in order from the enlargement side, the first lens group G1 includes lenses L11 to L13, the second lens group G2 includes lenses L21 to L24, and a third lens group. G3 includes a lens L31, the fourth lens group G4 includes lenses L41 to L42, and the fifth lens group G5 includes lenses L51 to L54. A DMD (digital micromirror device) as a light modulation element is disposed on the reduction end side. A cover glass (CG) (not shown) is disposed on the DMD surface facing the lens.

  In the projection zoom lens according to Example 4, when zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 is moved to the reduction side, and the third lens group G3 is enlarged. The fourth lens group G4 moves to the enlargement side, and the fifth lens group G5 moves to the enlargement side. Thus, zooming (magnification) from the wide-angle end to the telephoto end can be performed. The third lens group G3, the fourth lens group G4, and the fifth lens group G5 move at different timings.

  The first lens group G1 is a negative group, and includes a negative negative lens L11 on the reduction side, a negative negative lens L12 on the enlargement side, and a negative negative lens L13 on the reduction side.

  The second lens group G2 is a negative group, and includes a double-convex positive lens L21, a double-sided concave negative lens L22, a convex side L23 on the reduction side, and a negative negative lens L24 on the enlargement side. The lens L23 and the lens L24 are It is joined.

  The third lens group G3 is a positive group, and includes a double-sided positive lens L31.

  The fourth lens group G4 is a positive group, and includes a positive lens L41 having a convex surface on the magnifying side and a positive lens L42 having a convex surface on the magnifying side.

  The fifth lens group G5 is a negative group, and includes a convex negative lens L51 on the magnifying side, a double-sided positive lens L52, a concave negative lens L53 on the magnifying side, and a double-sided positive lens L54. L52 is joined.

  FIGS. 14 to 16 show aberration diagrams of the projection zoom lens according to Example 4. FIG. 14 shows the wide-angle end, FIG. 15 shows the middle, and FIG. 16 shows the telephoto end. Indicates spherical aberration, (b) indicates astigmatism, and (c) indicates distortion. In the spherical aberration (a) in each figure, the symbol R indicates red (wavelength is 625 nm), the symbol G indicates green (wavelength is 550 nm), and the symbol B indicates blue (wavelength is 460 nm). In each figure, astigmatism (b), symbol S indicates the sagittal image plane, and symbol T indicates the astigmatism of the tangential image plane. As shown in FIGS. 14 to 16, the aberration correction is good at each zoom position.

なお、表１３中の「ＩＮＦ」は無限大を表す。表１３中のアスタリスク（＊）は非球面であることを表し、その非球面係数の数値は表１４に示す通りである。また、表１３中のＳ６、Ｓ１３、Ｓ１５、Ｓ２０はズーミングした際に、下記の表１５に示すように変化する。なお、投射距離が１６００ｍｍ時のレンズ間隔である。また、上記に示した各条件式に係る数値は、表１６に示す通りである。 Each numerical value of Example 4 is shown in Table 13.

Note that “INF” in Table 13 represents infinity. An asterisk (*) in Table 13 represents an aspheric surface, and the numerical value of the aspheric coefficient is as shown in Table 14. Also, S6, S13, S15, and S20 in Table 13 change as shown in Table 15 below when zooming. Note that this is the lens interval when the projection distance is 1600 mm. Further, numerical values relating to the conditional expressions shown above are as shown in Table 16.

  FIGS. 17A and 17B are optical arrangement diagrams of the projection zoom lens according to Example 5. FIG. 17A shows the wide-angle end, and FIG. 17B shows the telephoto end. In the zoom lens for projection according to Example 5, in order from the enlargement side, the first lens group G1 includes lenses L11 to L13, the second lens group G2 includes lenses L21 to L24, and a third lens group. G3 includes a lens L31, the fourth lens group G4 includes lenses L41 to L42, and the fifth lens group G5 includes lenses L51 to L54. A DMD (digital micromirror device) as a light modulation element is disposed on the reduction end side. A cover glass (CG) (not shown) is disposed on the DMD surface facing the lens.

  In the projection zoom lens according to Example 5, when zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 is moved to the reduction side, and the third lens group G3 is enlarged. The fourth lens group G4 moves to the enlargement side, and the fifth lens group G5 moves to the enlargement side. Thus, zooming (magnification) from the wide-angle end to the telephoto end can be performed. The third lens group G3, the fourth lens group G4, and the fifth lens group G5 move at different timings.

  The first lens group G1 is a negative group, and includes a negative negative lens L11 on the reduction side, a negative negative lens L12 on the enlargement side, and a negative negative lens L13 on the reduction side.

  The second lens group G2 is a negative group, and includes a double-convex positive lens L21, a double-sided concave negative lens L22, a convex side L23 on the reduction side, and a negative negative lens L24 on the enlargement side. The lens L23 and the lens L24 are It is joined.

  The third lens group G3 is a positive group, and includes a double-sided positive lens L31.

  The fourth lens group G4 is a positive group, and includes a positive lens L41 having a convex surface on the magnifying side and a positive lens L42 having a convex surface on the magnifying side.

  The fifth lens group G5 is a negative group, and includes a convex negative lens L51 on the magnifying side, a double-sided positive lens L52, a concave negative lens L53 on the magnifying side, and a double-sided positive lens L54. L52 is joined.

  18 to 20 show aberration diagrams of the projection zoom lens according to Example 1. FIG. 18 shows the wide-angle end, FIG. 19 shows the middle, and FIG. 20 shows the telephoto end. Indicates spherical aberration, (b) indicates astigmatism, and (c) indicates distortion. In the spherical aberration (a) in each figure, the symbol R indicates red (wavelength is 625 nm), the symbol G indicates green (wavelength is 550 nm), and the symbol B indicates blue (wavelength is 460 nm). In each figure, astigmatism (b), symbol S indicates the sagittal image plane, and symbol T indicates the astigmatism of the tangential image plane. As shown in FIGS. 18 to 20, the aberration correction is in a good state at each zoom position.

なお、表１７中の「ＩＮＦ」は無限大を表す。表１７中のアスタリスク（＊）は非球面であることを表し、その非球面係数の数値は表１８に示す通りである。また、表１７中のＳ６、Ｓ１３、Ｓ１５、Ｓ２０はズーミングした際に、下記の表１９に示すように変化する。なお、投射距離が１６００ｍｍ時のレンズ間隔である。また、上記に示した各条件式に関する数値は、表２０に示す通りである。 Table 17 shows the numerical values of Example 5.

Note that “INF” in Table 17 represents infinity. An asterisk (*) in Table 17 represents an aspheric surface, and the numerical value of the aspheric coefficient is as shown in Table 18. Further, S6, S13, S15, and S20 in Table 17 change as shown in Table 19 below when zooming. Note that this is the lens interval when the projection distance is 1600 mm. The numerical values related to the conditional expressions shown above are as shown in Table 20.

  FIGS. 21A and 21B are optical arrangement diagrams of the projection zoom lens according to Example 6. FIG. 21A shows the wide-angle end, and FIG. 21B shows the telephoto end. In the zoom lens for projection according to Example 6, in order from the enlargement side, the first lens group G1 includes lenses L11 to L13, the second lens group G2 includes lenses L21 to L24, and a third lens group. G3 includes lenses L31 to L32. The fourth lens group G4 includes lenses L41. The fifth lens group G5 includes lenses L51 to L54. A DMD (digital micromirror device) as a light modulation element is disposed on the reduction end side. A cover glass (CG) (not shown) is disposed on the DMD surface facing the lens.

  In the projection zoom lens according to Example 6, when zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 is moved to the reduction side, and the third lens group G3 is enlarged. The fourth lens group G4 moves to the enlargement side, and the fifth lens group G5 moves to the enlargement side. Thus, zooming (magnification) from the wide-angle end to the telephoto end can be performed. The third lens group G3, the fourth lens group G4, and the fifth lens group G5 move at different timings.

  The first lens group G1 is a negative group, and includes a negative negative lens L11 on the reduction side, a negative negative lens L12 on the enlargement side, and a negative negative lens L13 on the reduction side.

  The second lens group G2 is a negative group, and includes a double-sided positive lens L21, a double-sided negative lens L22, a convex lens L23 on the reduction side, and a concave negative lens L24 on the enlargement side, and the lens L23 and the lens L24. Are joined.

  The third lens group G3 is a positive group, and includes a double-sided positive lens L31 and a convex positive lens L32 on the enlargement side.

  The fourth lens group G4 is a positive group, and includes a positive lens L41 having a convex surface on the enlargement side.

  The fifth lens group G5 is a negative group, and includes a concave negative lens L51 on the reduction side, a double-convex positive lens L52, a concave negative lens L53 on the enlargement side, and a double-convex positive lens L54. L52 is joined.

  22 to 24 show aberration diagrams of the projection zoom lens according to Example 6. FIG. 22 shows the wide-angle end, FIG. 23 shows the middle, and FIG. 24 shows the telephoto end. Indicates spherical aberration, (b) indicates astigmatism, and (c) indicates distortion. In the spherical aberration (a) in each figure, the symbol R indicates red (wavelength is 625 nm), the symbol G indicates green (wavelength is 550 nm), and the symbol B indicates blue (wavelength is 460 nm). In each figure, astigmatism (b), symbol S indicates the sagittal image plane, and symbol T indicates the astigmatism of the tangential image plane. As shown in FIGS. 22 to 24, the aberration correction is in a good state at each zoom position.

なお、表２１中の「ＩＮＦ」は無限大を表す。表２１中のアスタリスク（＊）は非球面であることを表し、その非球面係数の数値は表２２に示す通りである。また、表２１中のＳ６、Ｓ１３、Ｓ１５、Ｓ２０はズーミングした際に、下記の表２３に示すように変化する。なお、投射距離は１６００ｍｍ時のレンズ間隔である。また、上記に示した各条件式に係る数値は、表２４に示す通りである。

Table 21 shows numerical values of Example 6.

“INF” in Table 21 represents infinity. An asterisk (*) in Table 21 represents an aspheric surface, and the numerical value of the aspheric coefficient is as shown in Table 22. Further, S6, S13, S15, and S20 in Table 21 change as shown in Table 23 below when zooming. The projection distance is a lens interval at 1600 mm. In addition, numerical values relating to the conditional expressions shown above are as shown in Table 24.

  FIGS. 25A and 25B are optical arrangement diagrams of the projection zoom lens according to Example 7. FIG. 25A illustrates the wide-angle end, and FIG. 25B illustrates the telephoto end. In the zoom lens for projection according to Example 7, in order from the enlargement side, the first lens group G1 includes lenses L11 to L13, the second lens group G2 includes lenses L21 to L24, and a third lens group. G3 includes a lens L31, the fourth lens group G4 includes lenses L41 to L42, and the fifth lens group G5 includes lenses L51 to L54. A DMD (digital micromirror device) as a light modulation element is disposed on the reduction end side. A cover glass (CG) (not shown) is disposed on the DMD surface facing the lens.

  In the projection zoom lens according to Example 7, when zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 is moved to the reduction side, and the third lens group G3 is enlarged. The fourth lens group G4 moves to the enlargement side, and the fifth lens group G5 moves to the enlargement side. Thus, zooming (magnification) from the wide-angle end to the telephoto end can be performed. The third lens group G3, the fourth lens group G4, and the fifth lens group G5 move at different timings.

  The first lens group G1 is a negative group, and includes a negative negative lens L11 on the reduction side, a negative negative lens L12 on the enlargement side, and a negative negative lens L13 on the reduction side.

  The second lens group G2 is a negative group, and includes a double-sided positive lens L21, a double-sided negative lens L22, a convex lens L23 on the reduction side, and a concave negative lens L24 on the enlargement side. The lens L23 and the lens L24 Are joined.

  The third lens group G3 is a positive group, and includes a double-sided positive lens L31.

  The fourth lens group G4 is a positive group, and includes a positive lens L41 having a convex surface on the magnifying side and a positive lens L42 having a convex surface on the magnifying side.

  The fifth lens group G5 is a negative group, and includes a convex negative lens L51 on the magnifying side, a double-sided positive lens L52, a concave negative lens L53 on the magnifying side, and a double-sided positive lens L54. L52 is joined.

  26 to 28 show aberration diagrams of the projection zoom lens according to Example 7. FIG. 26 shows the wide-angle end, FIG. 27 shows the middle, and FIG. 28 shows the telephoto end. Indicates spherical aberration, (b) indicates astigmatism, and (c) indicates distortion. In the spherical aberration (a) in each figure, the symbol R indicates red (wavelength is 625 nm), the symbol G indicates green (wavelength is 550 nm), and the symbol B indicates blue (wavelength is 460 nm). In each figure, astigmatism (b), symbol S indicates the sagittal image surface, and symbol T indicates the tangential image surface astigmatism. As shown in FIGS. 26 to 28, the aberration correction is in a good state at each zoom position.

なお、表２５中の「ＩＮＦ」は無限大を表す。表２５中のアスタリスク（＊）は非球面であることを表し、その非球面係数の数値は表２６に示す通りである。また、表２５中のＳ６、Ｓ１３、Ｓ１５、Ｓ２０はズーミングした際に、下記の表２７に示すように変化する。なお、投射距離は１６００ｍｍ時のレンズ間隔である。また、上記に示した各条件式に係る数値は、表２８に示す通りである。 Table 25 shows each numerical value of Example 7.

Note that “INF” in Table 25 represents infinity. An asterisk (*) in Table 25 represents an aspheric surface, and the numerical value of the aspheric coefficient is as shown in Table 26. Also, S6, S13, S15, and S20 in Table 25 change as shown in Table 27 below when zooming. The projection distance is a lens interval at 1600 mm. In addition, numerical values relating to the conditional expressions shown above are as shown in Table 28.

  As described above, in the projection zoom lens according to the present invention, the aberration is corrected at a high level in the specific configurations shown in Examples 1 to 7, and spherical aberration, astigmatism, curvature of field, The lateral chromatic aberration and distortion are also sufficiently corrected. It is clear from each example that good optical performance can be secured.

  Although the projection zoom lenses of Examples 1 to 7 described above have a five-group configuration, the configuration of the projection zoom lens according to the present invention is not limited to this, and may be a six-group configuration. In the projection zoom lenses of Examples 1 to 11, when the sixth lens group G6 is provided, the sixth lens group G6 may be configured by a lens that corrects various aberrations. In this case, the refractive power of the sixth lens group is weaker than the refractive power of the fifth lens group. When zooming, the sixth lens group G6 also has the third lens group G3, the fourth lens group G4, and the fifth lens group. It moves to the enlargement side at a timing different from G5.

● Image display device ●
Next, an embodiment of an image display device according to the present invention will be described. FIG. 29 is a diagram showing a schematic configuration of a projection type projector device which is an example of the image display device according to the present invention.

  As shown in FIG. 29, the projector apparatus 1 includes a DMD 3 as a light modulation element. The DMD 3 is irradiated with light of three colors of RGB from the illumination optical system 2. By controlling the tilt of the micromirror included in the DMD 3 corresponding to each pixel at the timing when each color is irradiated, the reflected light from the micromirror is magnified by the projection lens 4 and is a screen that is the projection surface. 5 is projected and projected.

  The projector device 1 also has a condenser lens, an RGB color wheel, and a mirror (not shown), and it is necessary to secure a relatively large location. Due to the space between the projection lens 4 of the projector device 1 and the illumination optical system 2, it is necessary to secure the back focus of the projection lens 4 to some extent and reduce the lens diameter on the DMD 3 side.

  Therefore, by using the projection zoom lens according to the present invention described above as the projection lens 4, the angle of view is wider than before (ω = 39 to 45 °) and the high magnification x1.5 times zoom. An image display device having a ratio can be obtained.

F Focal length of the entire optical system Fno Numerical aperture ω Half angle of view R Radius of curvature,
D surface spacing,
Nd refractive index,
νd Abbe number,
L lens G lens group

JP 2011-69959 A JP 2011-69957 A JP 2003-015038 A JP 2005-292260 A

Claims (8)

A projection zoom lens that constitutes a projection optical system of an image display device that projects an image displayed on a display surface of an image display element onto a projection surface and displays the enlarged image,
Arranged from the projected surface side toward the image display element side,
A first lens group having negative refractive power;
A second lens group having negative refractive power;
A third lens group having positive refractive power;
A fourth lens group having a positive refractive power;
A fifth lens group having negative refractive power;
Consists of
When zooming from the wide-angle side to the telephoto side,
The first lens group is fixed, and the distance between the second lens group, the third lens group, the fourth lens group, and the fifth lens group is different from the adjacent lens group. Go to
The focal length of the negative lens closest to the image display element in the fifth lens group is F5n,
The focal length of the positive lens closest to the image display element in the fifth lens group is F5p,
When
-1.9 <F5n / F5p <-1.1
Projection zoom lens characterized by satisfying The fifth lens group is composed of negative-positive-negative-positive lenses in order from the projection surface side.
The projection zoom lens according to claim 1. When the focal length (mm) of the fifth lens group is F5,
-0.01 <1 / F5
Satisfy,
The projection zoom lens according to claim 1. The focal length of the third lens group is F3,
The focal length of the fourth lens group is F4,
When
1.3 <F3 / F4 <4.6
Satisfy,
The projection zoom lens according to claim 1. The focal length at the wide angle end of the entire projection optical system is Fw,
The focal length of the second lens group is F2,
When
−0.27 <Fw / F2 <−0.11
Satisfy,
The projection zoom lens according to claim 1. The image display element is a reflective image display element,
EPw is the distance from the display surface of the reflective image display element to the entrance pupil.
The distance from the rotation center axis of the closest spherical lens to the reflective image display element side to the outermost periphery of the reflective image display element is represented by DMDHT,
When
4.0 <| EPw / DMDHT | <4.5
Satisfy,
The projection zoom lens according to claim 1. When the half angle of view is ω,
39 ° <ω <45 °
Satisfy,
The projection zoom lens according to any one of claims 1 to 6. A light source;
An illumination optical system that illuminates the image display element with light emitted from the light source;
An image display element that displays an image by controlling emission of incident light incident via the illumination optical system;
A projection optical system for projecting the image displayed on the display surface of the image display element onto a projection surface and displaying the enlarged image;
With
It said projection optical system, an image display apparatus characterized by comprising a projection zoom lens according to any one of claims 1 to 7.

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