JP2019101362A - Zoom lens for projection and projection type image display device - Google Patents

Abstract

To provide a negative lead type novel zoom lens for projection in which an F value is constant in an entire range of variable magnification from a wide angle end to a telephoto end.SOLUTION: The zoom lens for projection is configured by arranging, in order from an enlargement side to a reduction side, a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, a third lens group G3 having negative refractive power, a fourth lens group G4 having positive refractive power, and a fifth lens group G5 having positive refractive power. An aperture diaphragm S is fixedly arranged in the fifth lens group or on the enlargement side of the fifth lens group. The reduction side is substantially telecentric. In zooming, the first lens group G1, the fifth lens group G5, and the aperture diaphragm S are fixed, the second lens group, the third lens group, and the fourth lens group are independently moved in an optical axis direction, and the F value is constant in the entire range of variable magnification by zooming.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a projection zoom lens and a projection type image display device.

A projection-type image display apparatus that enlarges and projects a small original image displayed on an "image display element" such as a liquid crystal display element or DMD onto a projection surface such as a screen is widely known as a projector or the like, and the distance to the projection surface Projectors equipped with a “projection zoom lens” that can change the size of a projection image without being bothered by are widely used because of their ease of use.
Conventionally, various types of projection zoom lenses have been known. However, the "negative lead" type in which the "negative refractive power lens unit" is disposed on the most enlargement side has a wide angle of view and reduction It is known that it is easy to realize optical characteristics suitable for a projection zoom lens, such as telecentricity on the side, a long back focus, and the like (for example, Patent Documents 1 to 3).

In general, in the zoom lens, the F number (numerical aperture: F number) changes due to zooming, and the F number at the telephoto end is larger than at the wide angle end and tends to be dark.
Patent Document 1 describes suppressing variation in F value associated with zooming, and the projection zoom lenses disclosed in Patent Documents 2 and 3 have "variation in F value associated with zooming". .

  SUMMARY OF THE INVENTION An object of the present invention is to realize a novel negative lead type projection zoom lens having a constant F-number over the entire variable magnification range from the wide-angle end to the telephoto end.

  The projection zoom lens according to the present invention includes, in order from the enlargement side to the reduction side, a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens having negative refractive power. A lens unit, a fourth lens unit having positive refractive power, and a fifth lens unit having positive refractive power, and an aperture stop fixedly arranged in the fifth lens unit or on the enlargement side of the fifth lens unit The first lens group, the fifth lens group and the aperture stop are fixed during zooming, while the second lens group, the third lens group and the fourth lens group are independent in the optical axis direction. To move, and the F value is constant in the entire variable magnification range by the zooming.

  According to the present invention, it is possible to realize a negative lead type novel projection zoom lens having a constant F-number over the entire variable magnification range from the wide-angle end to the telephoto end.

FIG. 2 is a diagram showing lens configurations at the wide-angle end and the telephoto end of Example 1; FIG. 5 is a diagram showing spherical aberration, astigmatism and distortion at the wide-angle end in Example 1. 5 is a diagram showing coma aberration at the wide-angle end of Example 1. FIG. FIG. 5 is a diagram showing spherical aberration, astigmatism and distortion at an intermediate focal length in Example 1. 5 is a diagram showing coma aberration at an intermediate focal length of Example 1. FIG. FIG. 5 is a diagram showing spherical aberration, astigmatism, and distortion at a telephoto limit in Example 1. 5 is a diagram showing coma aberration at the telephoto end in Example 1. FIG. FIG. 7 is a diagram showing lens configurations at the wide-angle end and the telephoto end of Example 2; FIG. 7 is a diagram showing spherical aberration, astigmatism and distortion at the wide-angle end in Example 2. FIG. 7 is a diagram showing coma aberration at the wide-angle end of Example 2. FIG. 7 is a diagram showing spherical aberration, astigmatism and distortion at an intermediate focal length in Example 2. FIG. 6 is a diagram showing coma aberration at an intermediate focal length of Example 2. FIG. 7 is a diagram showing spherical aberration, astigmatism and distortion at the telephoto end in Example 2. FIG. 7 is a diagram showing coma aberration at the telephoto end in Example 2. FIG. 14 is a diagram showing lens configurations at the wide-angle end and the telephoto end of Example 3; FIG. 16 is a diagram showing spherical aberration, astigmatism and distortion at the wide-angle end in Example 3. FIG. 16 is a diagram showing coma aberration at the wide-angle end of Example 3. FIG. 16 is a diagram showing spherical aberration, astigmatism, and distortion at an intermediate focal length in Example 3. FIG. 16 is a diagram showing coma aberration at the intermediate focal length of Example 3. FIG. 16 is a diagram showing spherical aberration, astigmatism and distortion at the telephoto end in Example 3. FIG. 16 is a diagram showing coma aberration at the telephoto end in Example 3. FIG. 18 is a diagram showing lens configurations at the wide-angle end and the telephoto end of the fourth embodiment. FIG. 16 is a diagram showing spherical aberration, astigmatism and distortion at the wide-angle end in Example 4. FIG. 16 is a diagram illustrating coma aberration at the wide-angle end of Example 4. FIG. 16 is a diagram showing spherical aberration, astigmatism and distortion at an intermediate focal length in Example 4. FIG. 18 shows coma aberration at the intermediate focal length of Example 4. FIG. 16 shows spherical aberration, astigmatism and distortion at the telephoto end in Example 4. FIG. 16 is a diagram showing coma aberration at the telephoto end of Example 4. FIG. 18 shows lens configurations at the wide-angle end and the telephoto end of Example 5. FIG. 18 shows spherical aberration, astigmatism and distortion at the wide-angle end in Example 5. FIG. 18 is a diagram illustrating coma aberration at the wide-angle end of Example 5. FIG. 16 is a diagram showing spherical aberration, astigmatism and distortion at an intermediate focal length of Example 5. FIG. 16 is a diagram showing coma at an intermediate focal length of Example 5. FIG. 16 is a diagram showing spherical aberration, astigmatism and distortion at the telephoto end in Example 5. FIG. 18 is a diagram showing coma aberration at the telephoto end of Example 5. FIG. 7 is a view showing a state in which the projection zoom lens of Example 1 is focused at a projection distance of 1640 mm to 911 mm at a wide angle end. FIG. 5 is a diagram showing spherical aberration, astigmatism, and distortion at a projection distance of 911 mm at the wide-angle end in Example 1. FIG. 7 is a diagram showing coma aberration at a projection distance of 911 mm at the wide-angle end in Example 1. It is a figure for demonstrating one Embodiment of a projection type image display apparatus.

  The configuration of the projection zoom lens described above, that is, “the first lens group having negative refractive power, the second lens group having positive refractive power, and the negative refractive power in order from the enlargement side to the reduction side The third lens group, the fourth lens group with positive refractive power, and the fifth lens group with positive refractive power are arranged, and the aperture stop is fixed on the enlargement side of the fifth lens group or the fifth lens group. The second lens group, the third lens group, and the fourth lens group are in the optical axis direction with the first lens group, the fifth lens group, and the aperture stop fixed during zooming. A configuration in which the F value is constant in the entire variable magnification range by zooming is referred to as “Configuration 1”.

Hereinafter, the present invention will be described according to the embodiment.
FIGS. 1, 8, 15, 22 and 29 illustrate five embodiments of the projection zoom lens. Of course, the projection zoom lens according to the present invention is not limited to these embodiments. The embodiments shown in FIG. 1, FIG. 8, FIG. 15, FIG. 22, and FIG. 29 correspond to specific examples 1 to 5 described later in this order.
In these figures, the upper figure shows the "lens configuration at the wide angle end", and the lower figure shows the "lens configuration at the telephoto end". The left side of the figure is the enlargement side (projected surface side), and the right side is the reduction side (image display element side). In order to avoid complexity, the symbols are made common throughout the above figures.
That is, the first lens group, the second lens group, the third lens group, the fourth lens group, and the fifth lens group are indicated by reference numerals G1, G2, G3, G4, and G5, and the "aperture stop" is indicated by reference numeral S. . Furthermore, “image display element” is indicated by a code MD. In these embodiments, a "liquid crystal panel" is assumed as the image display element MD, and a symbol CG in the figure indicates a cover glass of the image display surface of the liquid crystal panel.
In these embodiments, it is assumed that images of red, green, and blue color components are combined to enlarge and project a color image, and the symbol P in each of the above figures indicates “prism for color combination”. There is. The image display element MD shown in the figure is representatively shown as "a liquid crystal panel for green image component", and the other two color image display elements are not shown.

As shown in the figures, the projection zoom lens has a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, and a negative lens in the order from the enlargement side to the reduction side. A third lens group G3 having a refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a positive refractive power are disposed, and the enlargement side of the fifth lens group or the fifth lens group The aperture stop S is fixedly disposed on the
The projection zoom lens is substantially telecentric on the reduction side, and the first lens group G1, the fifth lens group G5, and the aperture stop S are fixed during zooming, and the second lens group G2, the third lens group G3, the fourth lens The group G4 moves independently in the optical axis direction.
Also, the F value is constant in the entire variable magnification range by zooming. “The F value is constant in the entire zoom range by zooming” includes not only the case where the F value is strictly constant in the entire zoom range but also the case where the F value is substantially constant.

As described above, the projection zoom lens according to the present invention is composed of five lens groups having "negative, positive, negative, positive, positive refractive power" from the enlargement side. Since the first lens group G1, the fifth lens group G5, and the aperture stop S are "fixed", they do not move during zooming.
During zooming, the three lens units of the second lens unit G2 to the fourth lens unit G4 move independently on the optical axis and are distributed to the optimum position, thereby achieving "good optical performance" over the entire zoom range. Is realized.
Since the aperture stop S and the fifth lens group G5 are fixed and the positional relationship between them is invariable, the diameter of the light flux exiting the image display element MD and passing through the aperture stop S is always "constant". Since the fifth lens group G5 has a positive refractive power, the angle with respect to the optical axis of the "marginal light beam coming out of the aperture stop S toward the enlargement side" is gentle, and the second to fourth lens groups G2 to G4 are zoomed. Even if it moves on the optical axis, it is possible to make "marginal light rays not be interrupted at all", and the F value can be made constant regardless of zooming.
Further, the aperture stop S for determining the brightness of the projection zoom lens is fixedly disposed on the enlargement side of the fifth lens group G5 or the fifth lens group G5, and the chief ray passing through the center of the aperture stop S also zooms. In this case, “good telecentricity on the reduction side” is realized over the entire zoom range.
The movement of the second lens group G2 to the fourth lens group G4 during zooming from the wide-angle end to the telephoto end is "independent from each other" as described above, but the second lens during zooming from the wide-angle end to the telephoto end The group G2, the third lens group G3, and the fourth lens group G4 can move from the reduction side to the enlargement side. This configuration is referred to as “configuration 2”.
In the projection zoom lens of the embodiment shown in each of the drawings, “movement of the second lens group G2 to the fourth lens group G4 in the zooming from the wide-angle end to the telephoto end” becomes as described in the second configuration. There is.

In the projection zoom lens of configuration 1 or 2, the back focus in air when the conjugate point on the enlargement side is at infinity: Bf, the focal length of the entire system at the wide angle end: f _W , the focal length of the first lens group: Condition f1:
(1) 1.0 <Bf / f _W <2.7
(2) 1.8 <| f1 / f _W | <3.5
It is preferable to satisfy This configuration is referred to as “configuration 3”.
In the projection zoom lens of configuration 1 or 2, the first lens group G1 sets “two lenses of a negative lens having a large curvature on the reduction side and a negative lens having a large curvature on the enlargement side from the enlargement side It is possible to have the arrangement disposed in the first lens group. This configuration is referred to as "configuration 4".
The projection zoom lens of the above configuration 1 or 2 or 3 or 4 is also a positive lens having a large curvature on the reduction side in the first lens group G1: LP and a negative lens having a large curvature on the enlargement side: LN Two lenses can be arranged in order from the enlargement side, and a “negative air lens having a large curvature on the reduction side” can be formed between the positive lens: LP and the negative lens: LN. This configuration is referred to as “configuration 5”.

  In FIGS. 1, 8, 15, 22, 29, and 36, “LP” and “LN” are used as a symbol indicating positive lens: LP and negative lens: LN, respectively.

The magnitude of the "curvature" in the above configurations 4 and 5 is "the magnitude of the absolute value of the curvature".
In the projection zoom lens of Configuration 5, the negative lens in the first lens group G1: Abbe number of _LN : _LN , and the partial dispersion ratio: θgF
(3) 0.01 <θgF-(0.6438-0.001682 v _LN ) <0.05
It is preferable to satisfy The configuration of the projection zoom lens that satisfies the condition (3) is referred to as “configuration 6”.

In the projection zoom lens according to any one of the configurations 1 to 6, the second lens group G2 can be configured of one positive lens. This configuration is referred to as “configuration 7”.
In the projection zoom lens of Configuration 7, the refractive index N _{2 G} with respect to the d-line of one positive lens forming the second lens group G2 is:
(4) 1.7 <N _{2 G}
Satisfy.
In the projection zoom lens according to any one of the configurations 1 to 7, the third lens group G3 can be configured of one negative lens. This configuration is referred to as “configuration 8”. In the projection zoom lens of Configuration 8, the refractive index _N3G for the d-line of one negative lens that constitutes the third lens group G3 _satisfies the condition:
(5) 1.7 <N _3G
Satisfy.

  In the projection zoom lens according to any one of the aspects 1 to 8, in the first lens group G1, the 1a sub lens group, the 1 b sub lens group having negative refracting power, and the positive The 1c sub lens unit moves on the optical axis from the enlargement side to the reduction side during focusing in which the 1c sub lens group having a power is arranged and the conjugate point on the enlargement side is moved from the long distance to the near direction. The lens groups can also be configured to move independently on the optical axis. This configuration is referred to as “configuration 9”.

The significance and the like of the conditions (1) to (5) listed above will be described below.
Parameter condition (1): Bf / f _W is the focal length of the entire system at the wide angle end: the fraction of "back focus in air when the conjugate point of the expansion side of infinity" for f _W, parameters: When bf / _{f W} becomes larger (smaller), the focal length at the wide angle end: _{f W} is small or becomes (large), the back focus: bf may become large (small).

When the focal length: f _W becomes smaller, the refractive power of the entire system becomes large and “correction of various aberrations” becomes difficult, and when the back focus: Bf becomes smaller, the optical arrangement on the image display element side (the above-mentioned prism P Arrangement etc. is likely to be difficult. Also, when the focal length: f _W becomes large, the refractive power of the whole system becomes small and "projected image becomes small" easily, and when the back focus: Bf becomes too large, a projection type image display apparatus including a projection zoom lens It is easy to make
Parameters: Bf / f _W by a range of conditions (1) and can be balanced optical performance and ease of optical arrangement of an image display device side of the projection zoom lens.

The parameter of the condition (2): | f1 / f _W | is a ratio of the focal length of the first lens group G1 to the focal length of the whole system at the wide-angle end: f _W : f1 as an absolute value. _| f1 / f W | the larger (smaller), the negative refractive power of the first lens group G1 is weak or becomes (stronger), the refractive power of the entire system may become stronger (weaker).

When the negative refractive power of the first lens group G1 weakens, the angle of view on the enlargement side decreases, and it becomes difficult to realize a wide angle of view as a projection zoom lens, and when the refractive power of the entire system becomes strong Correction is likely to be difficult.
When the negative refractive power of the first lens group G1 becomes strong, the angle of view on the enlargement side becomes large, but it tends to be difficult to keep good aberrations such as coma and field curvature. In addition, when the refractive power of the entire system becomes too small, “projected image is likely to be too small”.

In the range in which the condition (2) is satisfied, “wide angle of view and optical performance” can be compatible.
Therefore, the back focus, the wide angle of view, and the optical performance of the projection zoom lens can be well balanced by satisfying the conditions (1) and (2) in combination.

In the projection zoom lens of Configuration 4, the first lens group G1 has a configuration in which “the negative lens having a large curvature on the reduction side and the negative lens having a large curvature on the enlargement side are arranged in order from the enlargement side It is included in the first lens group.
The above-mentioned "two negative lenses have their concave surfaces facing each other", but the concave surface on the enlargement side in the "negative lens having a large curvature on the enlargement side" has "a small refraction effect on marginal rays", so Even if the curvature of the concave surface is increased, "a large negative refracting power can be given to the first lens group G1 without generating a large spherical aberration or coma aberration".

In addition, by using a glass material having a small refractive index (Nd) for the “negative lens having a large curvature on the enlargement side”, it is possible to reduce the “total Petzval sum”.
In the projection zoom lens of Configuration 5, in the first lens group G1, a positive lens having a large curvature on the reduction side: LP and a negative lens having a large curvature on the enlargement side: LN from the enlargement side By arranging in order, an “air lens” is formed between the positive lens: LP and the negative lens: LN as a negative lens having a large curvature on the reduction side, making it easy to correct lateral chromatic aberration. .

  Condition (3) in Configuration 6 is the condition for the negative lens in the above-mentioned Configuration 5: material of LN, and a negative lens: LN made of a material satisfying the condition (3) Can be small.

The partial dispersion ratio θgF in the condition (3) is defined as follows.
That is, when the refractive index of optical glass is “Ng for g line (435.83 nm), NF for F line (486.13 nm), NC for C line (656.27 nm), The dispersion ratio θgF is
θgF = (Ng-NF) / (NF-NC)
Defined by

Negative lens: Abbe number of _LN :: _LN and partial dispersion ratio: θgF satisfies the condition (3) so that the magnification chromatic aberration of the zoom lens for projection can be made “smaller”, and a good image can be obtained over a wide angle of view. It becomes possible.

In the projection zoom lens of configuration 7, the second lens group G2 is configured of a single positive lens satisfying the condition (4), and in the projection zoom lens of configuration 8, the third lens group G3 is condition (5) It consists of a single negative lens that satisfies
As in the configurations 7 and 8, by including the “lens group configured of one lens” in the five lens groups, it is possible to realize a low-cost and compact projection zoom lens.

  When the angle of view of the projector is increased, if the projection distance is changed due to the change of the distance to the screen, it is not always easy to perform focusing while maintaining the "flatness of the image plane".

  In the projection zoom lens of configuration 9, the first lens group G1 is divided into three sub lens groups from the magnification side: 1a sub lens group, 1 b sub lens group having negative refractive power, and 1 c sub lens group having positive refractive power. The 1c sub lens group moves on the optical axis from the enlargement side to the reduction side during focusing from a long distance to a short distance direction, and the 1 b sub lens group also moves independently on the optical axis. By changing the distance between the sub lens group 1a and the sub lens group 1b, the flatness of the image plane can be maintained, and a wide projection distance range can be provided.

Before describing a specific embodiment of the projection zoom lens, one embodiment of a projection type image display device will be described with reference to FIG.
FIG. 39 is a view for explaining a projector which is an example of the projection type image display device.
The projector indicated by reference numeral 10 is a device for projecting “image information” given from a computer or the like (not shown) as a color enlarged projection image on the projection surface S.
Reference numeral 11 is a "controller", reference symbol LR is a "red light source", reference symbol LG is a "green light source", reference symbol LB is a "blue light source", and reference symbol MDR is a "liquid crystal panel for red component image", reference symbol MDG indicates "a liquid crystal panel for green component image".
The code P indicates a prism for color synthesis. The prism P is a "cross prism using a dichroic film".
The symbol ZLN indicates a “projection zoom lens”. As the projection zoom lens ZLN, the projection zoom lenses of claims 1 to 9, for example, the projection zoom lenses of Examples 1 to 5 described later can be used.

The controller 11 is configured as a computer or a CPU, and blinks the red light source LR, the green light source LG, and the blue light source LB, and the “zoom mechanism and focus mechanism (both not shown) of the projection zoom lens ZLN. Control).
The controller 11 also controls the liquid crystal panels MDR, MDG, and MDB in accordance with “image information” given from the outside, and displays a red component image, a green component image, and a blue component image on these.
The red component image displayed on the liquid crystal panel MDR is irradiated with red light from the red light source LR, and the red light transmitted through the liquid crystal panel MDR is intensity-modulated by the red component image to become "red image light". Incident on P
The green component image displayed on the liquid crystal panel MDG is irradiated with green light from the green light source LG, and the green light transmitted through the liquid crystal panel MDG is intensity-modulated by the green component image to become "green image light". Incident on P
The blue component image displayed on the liquid crystal panel MDB is irradiated with blue light from the blue light source LB, and the blue light transmitted through the liquid crystal panel MDB is intensity-modulated by the blue component image to become "blue image light". Incident on P
The prism P combines the incident red image light, the green image light, and the blue image light into “one light flux”, and causes the light to enter the projection zoom lens ZLN as color image light.
The color image light enlarges and projects the “color image by image information” on the screen S which is a projection surface by the projection zoom lens ZNL.

Hereinafter, five specific examples of the projection zoom lens will be described.
As described above, Examples 1 to 5, which are the examples of these five examples, are specific numerical examples of the embodiment shown in FIG. 1, FIG. 8, FIG. 15, FIG. .
In all of the first to fifth embodiments, the projection zoom lens includes, in order from the enlargement side to the reduction side, the first lens group G1 having negative refractive power, the second lens group G2 having positive refractive power, and the negative lens A third lens group G3 having a refractive power of, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a positive refractive power are arranged.

In any of the embodiments, the first lens group G1 is, as shown in the drawing at the telephoto end, 1a sub lens group, 1 b sub lens group, 1 c sub lens group (respectively 1a, 1b, 1c) And is hereinafter referred to as sub lens group 1a, sub lens group 1b, and sub lens group 1c).
The sub lens group 1b has a negative lens having a large curvature on the reduction side, a negative lens having a large curvature on the reduction side, and a negative lens having a large curvature on the enlargement side, with concave surfaces facing each other, On the reduction side, a positive lens LP having a large curvature on the reduction side and a negative lens LN having a large curvature on the enlargement side are disposed, and between the positive lens LP and the negative lens LN It forms a negative air lens with a large curvature.
Further, the sub lens group 1c is configured by "one positive lens".

  In each of the drawings showing Example 1 to Example 5, the projection distance (the distance on the optical axis between the lens surface on the most enlargement side of the projection zoom lens and the screen being the projection surface) at both the wide-angle end and the telephoto end In this state, the distance between the sub lens units 1a to 1c is adjusted so as to focus on 1640 mm.

In the data notation of each example, “surface number” refers to the lens surface of each lens constituting the projection zoom lens, the aperture stop S, and the surface of the prism P from the enlargement side (screen side) to the reduction side (image display element The screen is represented by an "object plane", and the image display surface of an image display element (a liquid crystal panel is assumed) is represented as an "image plane".
“R” represents the radius of curvature (paraxial radius of curvature in the case of an aspheric surface) of each surface (including the surface of the aperture stop S, the prism P for color synthesis, and the surface of the cover glass CG), “D” Represents the surface separation on the optical axis.
"Nd" and "vd" indicate the "refractive index and Abbe number for d-line" of the material of each lens. “Image height” is the maximum height of the image display surface from the optical axis, “BF” is the lens surface on the most reduction side in the air (with no prism or cover glass) when the conjugate point on the enlargement side is infinity The distance to the paraxial image (back focus) is represented, and "total lens length" is represented by the distance from the lens surface on the most enlargement side to the lens surface on the most reduction side.
The unit of quantity with dimension of length is "mm" unless otherwise stated.

The zoom lens for projection in the following examples includes an aspheric lens, but the “aspheric shape” has an intersection point of the optical axis and the aspheric surface as an origin, and a height relative to the optical axis: h, displacement in the optical axis direction : Z, paraxial radius of curvature: R, conic constant: K, nth order aspheric coefficient: An, well known equation:
Z = (1 / R) · h ² / [1 + {{1-(1 + K) · (1 / R) ² · h ² }]
+ A 4 · h ⁴ + A 6 · h ⁶ + A 8 · h ⁸ + ... + An · h ⁿ
The above R, K, An are given to specify the shape. In addition, the surface which employ | adopted the aspherical surface attaches and shows "* mark" to surface number.

"Example 1"
Example 1 shows lens configurations at the wide-angle end (upper figure) and the telephoto end (lower figure) in FIG.

The third lens group G3 is composed of "one negative lens (bi-concave lens)", and the fourth lens group G4 is composed of "one positive lens (bi-convex lens)".
The aperture stop S is fixedly provided on the enlargement side of the fifth lens group G5.
The data of Example 1 in the case where the projection distance is 1640 mm is shown below.
"Lens data"
Face number R D Nd d d
Object surface 164 1640.000
1 103.021 12.000 1.51860 69.89
2 415.857 0.300
3 67.292 3.781 1.49700 81.61
4 36.210 16.663
5 110.582 2.500 1.49700 81.61
6 24.685 9.698
7 * 91.036 2.300 1.51633 64.07
8 * 23.188 11.642
9-44.074 1.900 1.52249 59.84
10 165.243 2.174
11-278.019 6.185 2.00100 29.13
12-43.925 2.143
13 -33.252 1.800 1.85896 22.73
14-91.509 1.000
15-136.550 6.295 1.56069 58.34
16-36.215 (variable)
17 60.411 1.600 1.59270 35.45
18 39.004 0.850
19 43.006 6.243 1.96300 24.11
20 -212.471 (variable)
21 -179.618 2.000 1.92286 20.88
22 99.691 (variable)
23 86.597 6.000 1.49700 81.61
24 -74.714 (variable)
25 (F-stop) ∞ 2.974
26 86.290 1.300 1.67270 32.17
27 46.628 3.476
28 -39.264 1.600 2.00100 29.13
29-433.119 0.300
30 * 100.294 4.233 1.51633 64.07
31 *-36.805 0.300
32 82.543 1.600 1.95000 29.37
33 45.201 0.200
34 43.642 9.183 1.49700 81.61
35-18.591 0.200
36-19.128 1.300 1.79504 28.69
37 66.385 1.357
38 112.963 6.646 1.92286 20.88
39-41.427 4.649
40 54.305 8.954 1.49700 81.55
41 -54.197 6.700
42 26 26.000 1.51680 64.17
43 ∞ 6.300
44 1. 1.900 1.48640 65.40
45 0.3 0.300
Image plane ∞.

"Aspheric surface data"
The aspheric surface data are shown below.
"Seventh"
K = 14.365290,
A4 = 2.480204 × 10 ⁻⁸ ,
A6 = -2.845828 x 10 ^-8 ,
A8 = 4.646706 × 10 ⁻¹¹ ,
A10 = -2.822074 x 10 ^-14 ,
A12 = −4.257172 × 10 ⁻¹⁷
"Eighth"
K = 9.581289 × 10 ^-2 ,
A4 = −6.559764 × 10 ⁻⁶ ,
A6 = −4.965575 × 10 ⁻⁸ ,
A8 = 3.655648 × 10 ⁻¹¹ ,
A10 = 3.692807 × 10 ^-14 ,
A12 = -2.803393 x 10 ^-16
"The 30th"
K = 53.448638,
A4 = −2.371323 × 10 ⁻⁶ ,
A6 = 3.770876 × 10 ⁻⁸ ,
A8 = -7.867310 × 10 ^-11,
A10 = 2.990470 × 10 ⁻¹² ,
A12 = -1.743495 × 10 ^-14
"The 31st"
K = 2.378309,
A4 = 1.576702 × 10 ⁻⁵ ,
A6 = 6.970018 × 10 ^-8 ,
A8 = -6.6.9071 × 10 ^-11 ,
A10 = 3.842160 × 10 ⁻¹² ,
A12 = -9.798815 × 10 ^-15.

"Variable interval"
In the lens data shown above, the surface distance displayed as “variable” is “variable distance”, and the values of the variable distance at each zoom position at the wide-angle end, intermediate focal length (displayed as middle) and telephoto end are Show.
Zoom position Wide-angle end Middle Telephoto end
D16 11.475 5.456 0.578
D20 4.901 2.766 1.000
D22 16.778 16.934 16.241
D24 0.300 8.298 15.635.

"Various data"
Various data at each zoom position at the wide-angle end, at the middle, and at the telephoto end are shown below.
Zoom position Wide-angle end Middle Telephoto end
Focal length 15.443 16.988 18.535
F value 2.0 2.0 2.0
Half angle of view 37.91 ° 35.28 ° 32.86 °
Image height 12.000 12.000 12.000
BF 31.719 31.719 31.719
Lens total length 178.800 178.800 178.800.

"Value of parameter of each conditional expression"
The values of the parameters of the conditions (1) to (5) are shown below.
(1) Bf / f _W = 2.054
(2) | f1 / f _W | = 2.557
(3) θgF-(0.6438-0.001682 v _LN ) = 0.0237
₍₅₎ N 3G = 1.92286.

A diagram of spherical aberration, astigmatism and distortion at the “wide-angle end” of the projection zoom lens of Example 1 is shown in FIG. 2, and a diagram of coma is shown in FIG. Each aberration diagram shows the aberration of green light having a wavelength of 545 nm, but the spherical aberration diagram and the coma aberration diagram also show the aberrations of wavelength: 635 nm and 460 nm, representing red and blue lights. In the astigmatism diagram, S indicates a sagittal image, and M indicates an aberration of a meridional image.
The diagram of spherical aberration, astigmatism and distortion at “intermediate focal length” is shown in FIG. 4, the diagram of coma at FIG. 5 and the diagram of spherical aberration, astigmatism and distortion at “telephoto end” The figure of coma is shown in FIG.

  The data shown above is for the projection distance: 1640 mm as described above, but the state of focusing from the projection distance: 1640 mm to the projection distance: 911 mm is shown in FIG. 36 at the wide angle end. As shown in the figure, in focusing to a projection distance of 911 mm, the sub lens unit 1c moves on the optical axis from the enlargement side to the reduction side, and the sub lens unit 1b also moves independently from the enlargement side to the reduction side and the sub lens The distance to group 1a is changed.

  Distances between the sub lens units 1a, 1b and 1c (surface distances: D4 and D14) when the projection zoom lens of Example 1 is focused to a projection distance of 911 mm, a sub lens unit 1c and a second lens unit G2 The spacing between the faces (surface spacing: D16) is shown below.

"Projection distance: 911 mm"
D4 16.898
D14 1.270
D16 10.970.

  FIG. 37 shows a diagram of spherical aberration, astigmatism and distortion at a projection distance of 911 mm at the wide-angle end in Example 1, and FIG. 38 shows a diagram of coma.

"Example 2"
Example 2 shows lens configurations at the wide-angle end (upper figure) and the telephoto end (lower figure) in FIG.

The data of Example 2 in the case where the projection distance is 1640 mm is shown below.
"Lens data"
Face number R D Nd d d
Object surface 164 1640.000
1 108.388 11.800 1.51860 69.89
2 465.437 0.300
3 63.199 4.835 1.49700 81.61
4 35.378 16.282
5 116.113 2.500 1.48749 70.44
6 24.154 9.133
7 * 74.079 2.300 1.49710 81.56
8 * 21.630 11.796
9 -40.800 2.038 1.56732 42.84
10 230.281 2.555
11-129.826 6.311 2.00330 28.27
12 -38.908 1.514
13 -32.660 1.933 1.80810 22.76
14 -109.712 1.025
15 -206.784 7.452 1.56883 56.36
16 -36.259 (variable)
17 51.285 1.600 1.59270 35.45
18 40.952 0.935
19 46.401 5.047 1.96300 24.11
20 -349.327 (variable)
21 -188.825 2.000 1.78472 25.72
22 71.466 (variable)
23 72.291 6.000 1.49700 81.61
24-78.452 (variable)
25 (F-stop) ∞ 8.276
26-51.420 1.600 2.00330 28.27
27 132.215 0.688
28 * 73.212 3.996 1.49710 81.56
29 *-41.215 0.300
30 64.510 1.600 1.95000 29.37
31 37.337 0.205
32 36.499 8.933 1.48749 70.44
33-18.73 0.20
34-20.033 1.300 1.79504 28.69
35 59.567 1.248
36 84.473 6.897 1.92286 20.88
37-44.541 6.815
38 46.174 7.138 1.49700 81.61
39 -87.588 6.700
40 ∞ 26.000 1.51680 64.17
41 ∞ 3.400
42 1. 1.900 1.48640 65.40
43 0.3 0.300
Image plane ∞.

"Aspheric surface data"
The aspheric surface data are shown below.
"Seventh"
K = 9.354169,
A4 = -6.709372 × 10 ^-7 ,
A6 = -3.519502 × 10 ^-8 ,
A8 = 5.191726 × 10 ⁻¹¹ ,
A10 = -2.751735 x 10 ^-14 ,
A12 = −5.948527 × 10 ⁻¹⁷
"Eighth"
K = -1.905384 × 10 ⁻² ,
A4 = -5.632101 ^10-6 ,
A6 = −5.997846 × 10 ⁻⁸ ,
A8 = 3.684867 × 10 ⁻¹¹ ,
A10 = 4.705355 × 10 ^-14 ,
A12 = -3.309977 x 10 ^-16
"The 28th"
K = 26.916453,
A4 = 4.858156 × 10 ⁻⁸ ,
A6 = 5.490046 × 10 ⁻⁸ ,
A8 = -1.884828 × 10 ^-10 ,
A10 = 4.076769 × 10 ⁻¹² ,
A12 = -1.426982 x 10 ^-14
"The 29th"
K = 2.430195,
A4 = 1.695632 × 10 ⁻⁵ ,
A6 = 8.750766 × 10 ⁻⁸ ,
A8 = 9.995242 × 10 ⁻¹¹ ,
A10 = 2.865782 × 10 ⁻¹² ,
A12 = 1.958361 * 10 < ^-15 >.

"Variable interval"
Values of variable intervals at each zoom position at the wide-angle end, at the middle, and at the telephoto end are shown below.
Zoom position Wide-angle end Middle Telephoto end D16 12.227 5.556 0.300
D20 6.076 3.265 1.024
D22 16.547 16.904 16.283
D24 0.300 9.425 17.543.

"Various data"
Various data at each zoom position at the wide-angle end, at the middle, and at the telephoto end are shown below.
Zoom position Wide-angle end Intermediate telephoto end Focal length 15.447 16.992 18.538
F number 2.0 2.0 2.0
Half angle of view 37.90 ° 35.27 ° 32.85 °
Image height 12.000 12.000 12.000
BF 28.819 28.819 28.819
Lens total length 181.700 181.700 181.700.

"Value of parameter of each conditional expression"
The values of the parameters of the conditions (1) to (5) are shown below.
(1) Bf / f _W = 1.866
(2) | f1 / f _W | = 2.633
(3) θgF-(0.6438-0.001682 v _LN ) = 0.0261
₍₅₎ N 3G = 1.78472.

  A diagram of spherical aberration, astigmatism and distortion at the wide angle end of the projection zoom lens of Example 2 is shown in FIG. 9, and a diagram of coma is shown in FIG. Also, the diagrams of spherical aberration, astigmatism and distortion at the intermediate focal length are shown in FIG. 11, those of coma are shown in FIG. 12, and those of spherical aberration, astigmatism and distortion at the telephoto end are shown in FIG. A diagram of coma is shown in FIG.

"Example 3"
The third embodiment shows a lens configuration at the wide-angle end and the telephoto end in FIG.
In the projection zoom lens of Example 3, the second lens group G2 is composed of “one positive lens”, and the third lens group G3 is composed of “one negative lens”.

The data of Example 3 in the case where the projection distance is 1640 mm is shown below.
"Lens data"
Face number R D Nd d d
Object surface 164 1640.000
1 118.466 11.924 1.51680 64.20
2 424.553 2.445
3 67.545 8.000 1.49700 81.61
4 35.586 16.778
5 96.693 2.500 1.49700 81.61
6 24.080 8.854
7 * 73.512 2.300 1.55332 71.68
8 * 22.850 11.487
9-40.822 3.850 1.59270 35.45
10 216.652 2.719
11-124.020 6.333 2.00100 29.13
12 -41.117 1.903
13 -32.8229 2.383 1.89286 20.36
14 -65.978 1.000
15 -151.586 7.706 1.61772 49.82
16 -38.129 (variable)
17 62.700 4.577 1.89286 20.36
18 -786.230 (variable)
19-269.799 2.000 1.96300 24.11
20 124.692 (variable)
21 86.083 6.000 1.49700 81.61
22 -92.871 (variable)
23 (F-stop) ∞ 11.234
24-58.358 1.600 2.00330 28.27
25 150.169 0.300
26 * 72.929 3.978 1.55332 71.68
27 * -46.585 0.300
28 43.913 1.794 1.91650 31.60
29 29.499 0.465
30 32.235 8.343 1.49700 81.61
31-19.843 0.209
32 -20.975 1.300 1.80000 29.84
33 63.841 2.010
34 89.450 9.675 1.92286 20.88
35-51.036 5.793
36 46.948 6.724 1.49700 81.61
37-155.039 6.700
38 ∞ 26.000 1.51680 64.17
39 ∞ 3.400
40 1. 1.900 1.48640 65.40
41 ∞ 0.300
Image plane ∞.

"Aspheric surface data"
The aspheric surface data are shown below.
"Seventh"
K = 9.309440,
A4 = -1.614417 × 10 ^-6 ,
A6 = -2.446763 ^10-8 ,
A8 = 3.418481 × 10 ^-11 ,
A10 = −1.009374 × 10 ⁻¹⁴ ,
A12 = -7.559080 x 10 ^-17
"Eighth"
K = 1.061858 × 10 ^-1 ,
A4 = −7.185966 × 10 ⁻⁶ ,
A6 = -4.735630 × 10 ^-8 ,
A8 = 3.626134 × 10 ⁻¹¹ ,
A10 = 1.693289 × 10 ^-14 ,
A12 = −3.182189 × 10 ⁻¹⁶
"The 26th"
K = 25.078508,
A4 = −1.175875 × 10 ⁻⁷ ,
A6 = 3.487578 × 10 ⁻⁹ ,
A8 = 5.209107 × 10 ⁻¹¹ ,
A10 = 1.227434 × 10 ⁻¹² ,
A12 = -9.164958 × 10 ^-15
"The 27th"
K = 2.669070,
A4 = 1.254988 × 10 ⁻⁵ ,
A6 = 4.080252 × 10 ⁻⁸ ,
A8 = 5.363199 × 10 ⁻¹¹ ,
A10 = 2.130407 × 10 ⁻¹² ,
A12 = -5.080341 10 ^-15 .

"Variable interval"
Values of variable intervals at each zoom position at the wide-angle end, at the middle, and at the telephoto end are shown below.
Zoom position Wide-angle end Middle Telephoto end D16 14.073 6.312 0.300
D18 9.486 4.839 1.066
D20 16.359 16.940 16.272
D22 0.300 12.127 22.580.

"Various data"
Various data at each zoom position at the wide-angle end, at the middle, and at the telephoto end are shown below.
Zoom position Wide-angle end Middle Telephoto end
Focal length 15.506 17.058 18.611
F number 2.0 2.0 2.0
Half angle of view 37.79 ° 35.15 ° 32.73 °
Image height 12.000 12.000 12.000
BF 28.819 28.819 28.819
Total lens length 196.700 196.700 196.700.

"Value of parameter of each conditional expression"
The values of the parameters of the conditions (1) to (5) are shown below.
(1) Bf / f _W = 1.859
(2) | f1 / f _W | = 3.013
(3) θgF-(0.6438-0.001682 v _LN ) = 0.0308
(4) N _{2 G} = 1.89286
₍₅₎ N 3G = 1.96300.

  A diagram of spherical aberration, astigmatism and distortion at the wide-angle end of the projection zoom lens of Example 3 is shown in FIG. 16 and a diagram of coma is shown in FIG. Figures of spherical aberration, astigmatism and distortion at the intermediate focal length are shown in Figure 18; figures of coma are shown in Figure 19; figures of spherical aberration, astigmatism and distortion at the telephoto end are shown in Figure 20; coma Is shown in FIG.

"Example 4"
The fourth embodiment shows a lens configuration at the wide-angle end and the telephoto end in FIG.
In the fourth embodiment, the aperture stop S is fixedly disposed in the fifth lens unit.

The data of Example 4 in the case where the projection distance is 1640 mm is shown below.
"Lens data"
Face number R D Nd d d
Object surface 164 1640.000
1 120.679 9.490 1.53775 74.70
2 545.924 0.300
3 70.880 4.320 1.49700 81.61
4 34.261 15.781
5 143.350 2.500 1.49700 81.61
6 26.910 8.94
7 * 84.774 2.300 1.51633 64.07
8 * 24.224 11.868
9 -45.274 1.900 1.48749 70.44
10 127.901 0.459
11 142.088 7.336 2.00100 29.13
12 -65.302 2.243
13-43.539 1.805 1.92119 23.96
14 -3622.315 1.000
15 -564.924 8.275 1.56384 60.67
16-35. 880 (variable)
17 125.901 1.600 1.54072 47.20
18 42.864 0.353
19 43.401 6.398 2.00330 28.27
20 -231.555 (variable)
21 -125.775 2.000 1.96300 24.11
22 134.995 (variable)
23 -74.751 2.463 1.92286 20.88
24 -60.482 0.300
25 67.897 4.628 1.49700 81.61
26 -149.307 (variable)
27-187.360 1.300 1.61772 49.82
28 222.734 0.311
29 (F-stop) ∞ 9.267
30 -39.962 1.600 2.00100 29.13
31-329.750 0.300
32 * 128.430 4.130 1.51633 64.07
33 * -34.257 0.300
34 108.120 1.600 2.00100 29.13
35 42.9 39 0.258
36 43.266 8.801 1.49700 81.61
37 -19.878 0.202
38-21.827 1.300 1.79504 28.69
39 75.144 1.245
40 125.088 6.135 1.92286 20.88
41-44.512 3.963
42 79.327 9.028 1.49700 81.61
43-43.264 10.000
44 ∞ 26.000 1.51680 64.17
45 ∞ 8.000
46 1. 1.900 1.48640 65.40
47 0.3 0.300
Image plane ∞.

"Aspheric surface data"
The aspheric surface data are shown below.
"Seventh"
K = 11.865693,
A4 = -1.416193 × 10 ^-6 ,
A6 = -2.872617 × 10 ^-8 ,
A8 = 3.138193 × 10 ⁻¹¹ ,
A10 = −5.368166 × 10 ⁻¹⁵ ,
A12 = -5.072983 x 10 ^-17
"Eighth"
K = 8.809099 x 10 ^-2 ,
A4 = -6.258062 ^10-6 ,
A6 = -4.549968 x ^10-8 ,
A8 = 2.781473 × 10 ⁻¹¹ ,
A10 = 1.722554 × 10 ⁻¹⁴ ,
A12 = -1.456021 x 10 ^-16
"The 32nd"
K = 53.971438,
A4 = -4.897058 ^10-6 ,
A6 = 4.424815 × 10 ⁻⁸ ,
A8 = -1.800012 × 10 ⁻¹¹ ,
A10 = 1.275300 × 10 ⁻¹² ,
A12 = -9.497954 × 10 ^-15
"33rd"
K = 1.802171,
A4 = 1.622565 × 10 ⁻⁵ ,
A6 = 6.947151 × 10 ⁻⁸ ,
A8 = -1.144016 × 10 ^-10 ,
A10 = 3.371100 × 10 ⁻¹² ,
A12 = -1.348165 x 10 ^-14 .

"Variable interval"
Values of variable intervals at each zoom position at the wide-angle end, at the middle, and at the telephoto end are shown below.
Zoom position Wide-angle end Middle Telephoto end D16 13.400 6.095 0.300
D20 8.300 4.580 1.227
D22 15.393 16.461 16.495
D26 0.700 10.657 19.771.

"Various data"
Various data at each zoom position at the wide-angle end, at the middle, and at the telephoto end are shown below.
Zoom position Wide-angle end Intermediate telephoto end Focal length 15.405 16.946 18.488
F number 2.0 2.0 2.0
Half angle of view 38.00 ° 35.36 ° 32.95 °
Image height 12.000 12.000 12.000
BF 36.719 36.719 36.719
Total lens length 183.800 183.800 183.800.

"Value of parameter of each conditional expression"
The values of the parameters of the conditions (1) to (5) are shown below.
(1) Bf / f _W = 2.384
(2) | f1 / f _W | = 2.679
(3) θgF-(0.6438-0.001682 v _LN ) = 0.0151
₍₅₎ N 3G = 1.96300.

  FIG. 23 shows a diagram of spherical aberration, astigmatism and distortion at the wide-angle end of the projection zoom lens of Example 4, and FIG. 24 shows a diagram of coma. The diagrams of spherical aberration, astigmatism and distortion at the intermediate focal length are shown in FIG. 25, the diagrams of coma are shown in FIG. 26, the diagrams of spherical aberration, astigmatism and distortion at the telephoto end are shown in FIG. Is shown in FIG.

"Example 5"
The fifth embodiment shows a lens arrangement at the wide-angle end and the telephoto end in FIG.
The data of Example 5 in the case where the projection distance is 1640 mm are shown below.
"Lens data"
Face number R D Nd d d
Object surface 164 1640.000
1 105.223 9.584 1.48749 70.44
2 431.627 0.300
3 61.979 3.000 1.49700 81.61
4 33.564 15.453
5 86.881 2.500 1.49700 81.61
6 23.545 8.502
7 * 72.394 2.300 1.51633 64.07
8 * 21.756 11.703
9-35.802 1.900 1.64769 33.79
10-346.014 2.058
11-79.139 4.954 2.00100 29.12
12 -38.474 2.259
13 -29. 596 1.800 1.89286 20.36
14-45.413 1.000
15 -70.726 5.253 1.57099 50.80
16 -32.961 (variable)
17 66.582 1.600 1.67270 32.17
18 49.257 0.300
19 49.277 5.296 2.00060 25.46
20 -308.531 (variable)
21 -112.289 2.000 1.90200 25.26
22 181.608 (variable)
23-111.576 2.573 1.51860 69.89
24 -69.430 0.300
25 85.82 4.128 1.49700 81.61
26 -98.182 (variable)
27 (F-stop) 12. 12.441
28-41.687 1.600 2.00100 29.13
29 419.159 0.375
30 * 94.798 7 4.017 1.51633 64.07
31 * -38.396 0.300
32 79.251 1.600 1.95000 29.37
33 42.119 0.508
34 48.795 8.195 1.49700 81.61
35-19.169 0.200
36-21.096 1.300 1.80000 29.84
37 89.346 1.922
38 163.291 5.405 1.92286 20.88
39-47.011 0.948
40 53.775 7.330 1.49700 81.61
41-59.839 6.000
42 26 26.000 1.51680 64.17
43 ∞ 7.000
44 1. 1.900 1.48640 65.40
45 0.3 0.300
Image plane ∞.

"Aspheric surface data"
The aspheric surface data are shown below.
"Seventh"
K = 9.963495,
A4 = −2.539107 × 10 ⁻⁶ ,
A6 = -2.670658 ^10-8 ,
A8 = 4.050891 × 10 ^-11 ,
A10 = -1.662066 × 10 ^-14 ,
A12 = -1.112798 x 10 ^-16
"Eighth"
K = 9.579134 × 10 ^-2 ,
A4 = −9.973 070 × 10 ⁻⁶ ,
A6 = -5.488668 × 10 ^-8 ,
A8 = 5.047420 × 10 ⁻¹¹ ,
A10 = −7.874270 × 10 ⁻¹⁵ ,
A12 = -4.576713 × 10 ^-16
"The 30th"
K = 46.340408,
A4 = -5.514798 x 10 ^-7 ,
A6 = 5.002732 × 10 ⁻⁸ ,
A8 = −2.025546 × 10 ⁻¹¹ ,
A10 = 2.351359 × 10 ⁻¹² ,
A12 = -1.341363 x 10 ^-14
"The 31st"
K = 1.498417,
A4 = 1.750643 × 10 ⁻⁵ ,
A6 = 8.550681 × 10 ⁻⁸ ,
A8 = 2.383155 × 10 ⁻¹¹ ,
A10 = 3.809954 × 10 ⁻¹² ,
A12 = -1.082888 * 10 < ^-14 >.

"Variable interval"
Values of variable intervals at each zoom position at the wide-angle end, at the middle, and at the telephoto end are shown below.
Zoom position Wide-angle end Middle Telephoto end D16 11.169 5.104 0.300
D20 6.563 3.797 1.458
D22 15.863 16.604 16.390
D26 0.300 8.390 15.747.

"Various data"
Various data at each zoom position at the wide-angle end, at the middle, and at the telephoto end are shown below.
Zoom position Wide-angle end Intermediate telephoto end Focal length 15.378 16.916 18.455
F number 2.0 2.0 2.0
Half angle of view 38.07 ° 35.43 ° 33.01 °
Image height 12.000 12.000 12.000
BF 31.719 31.719 31.719
Lens total length 168.800 168.800 168.800.

"Value of parameter of each conditional expression"
The values of the parameters of the conditions (1) to (5) are shown below.
(1) Bf / f _W = 2.063
(2) | f1 / f _W | = 2.280
(3) θgF-(0.6438-0.001682 v _LN ) = 0.0308
₍₅₎ N 3G = 1.90200.

  A diagram of spherical aberration, astigmatism and distortion at the wide angle end of the projection zoom lens of Example 5 is shown in FIG. 30, and a diagram of coma is shown in FIG. The diagrams of spherical aberration, astigmatism and distortion at the intermediate focal length are shown in FIG. 32, the diagrams of coma are shown in FIG. 33, the diagrams of spherical aberration, astigmatism and distortion at the telephoto end are shown in FIG. Is shown in FIG.

In each embodiment, each aberration is well corrected at the wide-angle end, the intermediate focal length, and the telephoto end, and has high performance.
As described above, according to the present invention, the following projection zoom lens and projection type image display apparatus can be realized.
[1]
In order from the enlargement side to the reduction side, a first lens group (G1) having negative refractive power, a second lens group (G2) having positive refractive power, and a third lens group (G3) having negative refractive power A fourth lens group (G4) with positive refractive power, a fifth lens group (G5) with positive refractive power, and an aperture stop on the enlargement side of the fifth lens group or the fifth lens group S) is fixedly arranged, the reduction side is substantially telecentric, and the first lens group (G1), the fifth lens group (G5) and the aperture stop (S) are fixed during zooming, and the second lens Projection zoom lens in which the group (G2), the third lens group (G3), and the fourth lens group (G4) move independently in the optical axis direction, and the F value is constant in the entire variable magnification range by zooming Examples 1 to 5).

[2]
The zoom lens for projection according to [1], wherein the second lens group (G2), the third lens group (G3), and the fourth lens group (G4) are on the reduction side during zooming from the wide angle end to the telephoto end. The projection zoom lens (examples 1-5) which moves to an expansion side from this.

[3]
The zoom lens for projection according to [1] or [2], wherein the back focus in air when the conjugate point on the enlargement side is at infinity: Bf, the focal length of the entire system at the wide-angle end: f _W , first Lens unit focal length: f1, condition:
(1) 1.0 <Bf / f _W <2.7
(2) 1.8 <| f1 / f _W | <3.5
Projection zoom lens that satisfies the above (Examples 1 to 5).

[4]
The zoom lens for projection according to any one of [1] to [3], wherein the first lens group (G1) is a negative lens having a large curvature on the reduction side and a negative lens having a large curvature on the enlargement side A projection zoom lens (Examples 1 to 5) having a configuration in which two lenses of lenses are arranged in order from the enlargement side.

[5]
The zoom lens for projection according to any one of [1] to [4], wherein the first lens unit is a positive lens having a large curvature on the reduction side: LP, and a negative lens having a large curvature on the enlargement side Lenses: Two lenses of LN are arranged in order from the enlargement side, and for projection, a negative air lens with a large curvature on the reduction side is formed between the positive lens: LP and the negative lens: LN Zoom lens (Examples 1 to 5).

[6]
[5] The projection zoom lens according to [5], wherein the negative lens in the first lens group (G1): Abbe's number of the material of LN: LN _LN , the partial dispersion ratio: θgF, the conditions:
(3) 0.01 <θgF-(0.6438-0.001682 v _LN ) <0.05
Projection zoom lens that satisfies the above (Examples 1 to 5).

[7]
The zoom lens for projection according to any one of [1] to [6], wherein the second lens group (G2) is composed of a single positive lens, and the refractive index of the material of the positive lens with respect to d-line : N _2G, but conditions:
(4) 1.7 <N _{2 G}
Projection zoom lens that satisfies the above (Example 3).

[8]
The zoom lens for projection according to any one of [1] to [7], wherein the third lens group (G3) is composed of a single negative lens, and the refractive index of the material of the negative lens with respect to d-line : N _3G, but conditions:
(5) 1.7 <N _3G
Projection zoom lens that satisfies the above (Examples 1 to 5).

[9]
The zoom lens for projection according to any one of [1] to [8], wherein the first lens group is a 1a sub lens group having a negative refractive power in order from the enlargement side to the reduction side. The sub lens group includes a 1 c sub lens group having a positive refractive power, and the 1 c sub lens group has an enlargement on the optical axis during focusing for moving a conjugate point on the enlargement side from a long distance to a short distance direction. A projection zoom lens (Examples 1 to 5) in which the 1b sub lens unit is also moved independently on the optical axis while moving from the lens to the reduction side.

[10]
A projection type image display apparatus (FIG. 39) equipped with the projection zoom lens according to any one of [1] to [9].
Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the specific embodiments described above, and the invention described in the appended claims unless otherwise limited in the above description. Various modifications and changes are possible within the scope of the present invention.
The effects described in the embodiments of the present invention merely list the preferable effects resulting from the invention, and the effects of the invention are not limited to those described in the embodiments.

G1 first lens group G2 second lens group G3 third lens group G4 fourth lens group G5 fifth lens group S aperture stop
P Prism CG Cover Glass MD Image Display Element

Patent No. 4864600 Patent No. 5596500 gazette Patent No. 5302123

Claims (10)

A first lens unit having negative refractive power, a second lens unit having positive refractive power, a third lens unit having negative refractive power, and a third lens unit having positive refractive power in order from the enlargement side to the reduction side A fourth lens group, a fifth lens group having positive refractive power, and an aperture stop fixedly disposed in the fifth lens group or on the enlargement side of the fifth lens group, and the reduction side is substantially telecentric,
During zooming, the first lens group, the fifth lens group, and the aperture stop are fixed, and the second lens group, the third lens group, and the fourth lens group move independently in the optical axis direction, and the total variation due to the zooming Projection zoom lens whose F-number is constant in the zoom range. The projection zoom lens according to claim 1,
During zooming from the wide-angle end to the telephoto end, the second lens group, the third lens group, and the fourth lens group move from the reduction side to the enlargement side. The projection zoom lens according to claim 1 or 2,
Back focus in air when the conjugate point on the magnification side is at infinity: Bf, focal length of the entire system at the wide-angle end: f _W , focal length of the first lens group: f1, the conditions:
(1) 1.0 <Bf / f _W <2.7
(2) 1.8 <| f1 / f _W | <3.5
Projection zoom lens that satisfies the requirements. The projection zoom lens according to any one of claims 1 to 3, wherein
The first lens group is a projection zoom lens having a configuration in which a negative lens having a large curvature on the reduction side and a negative lens having a large curvature on the enlargement side are arranged in order from the enlargement side. It is a zoom lens for projection in any one of Claims 1-4,
In the first lens group, a positive lens having a large curvature on the reduction side: LP and a negative lens having a large curvature on the enlargement side: two lenses of LN are sequentially disposed from the enlargement side, and the positive lens: LP And the negative lens: A projection zoom lens in which a negative air lens having a large curvature on the reduction side is formed between LN. The projection zoom lens according to claim 5, wherein
Negative lens in the first lens group: Abbe number of the material of _LN : _LN , partial dispersion ratio: θgF, the conditions:
(3) 0.01 <θgF-(0.6438-0.001682 v _LN ) <0.05
Projection zoom lens that satisfies the requirements. The projection zoom lens according to any one of claims 1 to 6, wherein
The second lens group is composed of a single positive lens, and the refractive index N _{2 G} of the material of the positive lens with respect to d-line _satisfies the condition:
(4) 1.7 <N _{2 G}
Projection zoom lens that satisfies the requirements. The zoom lens for projection according to any one of claims 1 to 7, wherein
The third lens group is composed of one negative lens, and the refractive index of the material of the negative lens with respect to d-line: N _{3 G} , the condition:
(5) 1.7 <N _3G
Projection zoom lens that satisfies the requirements. The projection zoom lens according to any one of claims 1 to 8, wherein
The first lens group includes, in order from the enlargement side to the reduction side, the 1a sub lens group, the 1 b sub lens group having negative refractive power, and the 1 c sub lens group having positive refractive power. The 1c sub lens unit moves on the optical axis from the enlargement side to the reduction side during focusing in which the conjugate point of the lens moves from the long distance to the near distance direction, and the 1 b sub lens group also moves independently on the optical axis Projection zoom lens.   The projection type image display apparatus carrying the zoom lens for projection in any one of Claims 1-9.

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