Embodiments of the invention will be described below.
The zoom lens of the present invention is a “projection zoom lens” as described above.
As described above, the “projection lens” uses “oblique light” as the imaging light beam, and the projection zoom lens according to the present invention also uses “oblique light beam” as the projection light beam for forming the projection image. It is done.
1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, and 27, the zoom lens for projection is implemented. 14 examples are shown. The projection zoom lens shown in FIG. 7 is composed of a plurality of lenses in both the third lens group and the fifth lens group, and is a “reference example” that is different from the projection zoom lens of the present invention. However, in order to avoid complication, the following description will be made as an “embodiment”.
The zoom lenses according to these embodiments correspond to specific examples 1 to 14 described later in this order. The projection zoom lens having the configuration shown in FIG. 7 is a specific example of the reference example, and will be described as a fourth embodiment below.
In each figure, the left side of the figure is the “enlargement side” and the right side is the “reduction side”. In order to avoid complications, the symbols are shared in these drawings.
In the drawings, reference numeral G1 indicates a first lens group, reference numeral G2 indicates a second lens group, reference numeral G3 indicates a third lens group, reference numeral G4 indicates a fourth lens group, and reference numeral G5 indicates a fifth lens group.
For each lens, the j-th lens counted from the magnification side in the i-th lens group Gi is denoted by Lij.
In other words, the projection zoom lens according to the embodiment shown in each drawing has a five-lens group configuration in which the first lens group G1 to the fifth lens group G5 are arranged from the enlargement side toward the reduction side.
An “aperture stop” is disposed below the third lens group G3.
Further, in each of the drawings, the symbol CG indicates “a cover glass of an image display element (light valve)”.
In these embodiments and examples, “DMD as a micromirror device” is assumed as the light valve, but of course, the light valve is not limited to this.
In each figure, the upper diagram shows “lens group arrangement at wide angle end (indicated as wide angle)”, and the lower diagram shows “lens group arrangement at telephoto end (indicated as telephoto)”.
Also, the arrows drawn between the upper and lower figures in these figures indicate the transition of the second lens group G2 to the fifth lens group G5 during zooming from the wide-angle end to the telephoto end. Indicates direction.
The first lens group G1 is fixed during zooming.
In the projection zoom lens shown in each of the drawings, the first lens group G1 and the second lens group G2 both have a negative refractive power, and the third lens group has a positive refractive power.
The refractive power of the fourth lens group G4 and the fifth lens group G5 can be positive for the fourth lens group and “positive or negative” for the fifth lens group.
The refractive power of the fourth lens group G4 and the fifth lens group G5 can also be negative for the fourth lens group and “positive or negative” for the fifth lens group.
That is, the refractive powers of the fourth and fifth lens groups G4 and G5 can be a combination of “positive / negative”, “positive / positive”, “negative / negative”, and “negative / positive”.
Hereinafter, a lens group having a positive refractive power is also referred to as a “positive group”, and a lens group having a negative refractive power is also referred to as a “negative group”.
Condition (1) is a condition for achieving both “large back focus and short focal length”. As is clear from condition (1), at the wide angle end where the focal length of the entire system is the shortest, the principal point position on the reduction side is positioned on the reduction side with respect to the lens surface on the most reduction side of the fifth lens group. .
As described above, the back focus is from the lens surface on the most reduced side of the fifth lens group on the most reduced side to the surface on the enlarged side of the cover glass of the image display element when the projection distance is 1600 (mm). The actual distance at the wide-angle end is Bf, and the focal distance at the wide-angle end: Fw is a focal distance when the projection distance is 1600 (mm).
When the lower limit of the condition (1) is exceeded, the back focus becomes small with respect to the focal length at the wide-angle end, and the layout of the projection zoom lens and the illumination box tends to be difficult.
In particular, in the “region with a wide angle of view exceeding 34 degrees” as shown in the embodiment, the layout is difficult.
Even when three liquid crystal panels are used as light valves, the layout difficulty is the same because a large back focus is required for the arrangement of the color synthesis prism.
Condition (2) is a condition for achieving both “good optical performance and large back focus”.
If the lower limit of the condition (2) is exceeded, a larger back focus can be obtained, but this is not desirable because the refractive power of the first lens group increases and the field curvature tends to occur greatly.
If the upper limit of condition (2) is exceeded, curvature of field and coma will be good, but this is not desirable because the back focus will be small.
“Fw1-2” is a combined focal length at the wide-angle end of the first lens group and the second lens group.
“D2G-3G” is a distance from the most reduction side surface of the second lens unit to the most enlargement side surface of the third lens unit at the wide angle end.
“D5” is the effective diameter of the lens on the most reduction side of the fifth lens group.
Condition (3) is an effective condition for realizing “a good focal length and a short focal length at the wide-angle end”.
If the lower limit of condition (3) is exceeded, a shorter focal length can be achieved, but field curvature and coma tend to be excessive.
If the upper limit of condition (3) is exceeded, the field curvature and coma aberration will be good, but it will be difficult to achieve a short focal length.
Condition (4) is a condition for achieving both “compactness and large back focus”. The positive lens group of the third lens group or the fourth lens group serves as a variator.
When the lower limit of the condition (4) is exceeded, the refractive power of the third lens group or the fourth lens group increases, and the back focus tends to be shortened.
When the upper limit of the condition (4) is exceeded, the back focus increases, but it tends to be a lens lacking compactness.
Condition (5) is a condition for achieving both “compactness and large back focus”.
If the lower limit of the condition (5) is exceeded, the refractive power (absolute value) of the first to fifth lens units will increase, and it will be difficult to maintain good “field curvature and coma” during zooming. .
If the upper limit of condition (5) is exceeded, the refractive power of each lens group will be small, the total lens length will be large, and it will be difficult to ensure compactness.
Condition (6) is a condition in which the back focus and the “lens diameter of the lens on the most reduction side” are optimized.
This is a condition relating to the ease of layout between the components related to the image display element such as an illumination box and a liquid crystal panel and the projection zoom lens.
When the condition (6) is satisfied, the layout of the illumination box, the color synthesizing prism, etc. and the projection zoom lens is easy.
Outside the range of condition (6), the layout is likely to be difficult.
When the projection zoom lens is configured with the refractive power of the fourth lens group set to “negative”, the following conditions are satisfied from the ranges of the above conditions (1) and (2):
(1A) 2.68 ≦ Bf / Fw
(2A) 3.2 <| F1 | / Fw <3.5
It is good to satisfy.
In this case, one or more of the following conditions (3A) to (6A) should be satisfied. These conditions (1A) to (6A) are within the ranges of the conditions (1) to (6).
(3A) 0.9 <| Fw1-2 | / D2G-3G <1.1
(4A) 0.5 < Fw / F3o4 <0.6
(5A) 4.90 <OAL / Bf <4.95
(6A) 0.5 <D5 / Bf <0.6.
The parameters of the conditions (3A) to (6A) are the same as the parameters of the conditions (3) to (6).
When the projection zoom lens is configured with the fourth lens group as a negative group, the conditions (1A) and (2A) are satisfied, and further, one or more of the conditions (3A) to (6A) are satisfied. The roles played by the conditions (1) to (6) can be made to function similarly.
When the projection zoom lens is configured with the refractive power of the fourth lens group as “positive”, the following conditions are satisfied from the ranges of the above conditions (1) and (2):
(1B) 1.9 ≦ Bf / Fw
(2B) 1.2 <| F1 | / Fw <2.1
It is good to satisfy.
In this case, one or more of the following conditions (3B) to (6B) should be satisfied. These conditions (1B) to (6B) are within the ranges of the conditions (1) to (6).
(3B) 0.8 <| Fw1-2 | / D2G-3G <1.5
(4B) 0.35 < Fw / F3o4 <0.70
(5B) 4.0 <OAL / Bf <4.7
(6B) 0.4 <D5 / Bf <0.6.
The parameters of the conditions (3B) to (6B) are the same as the parameters of the conditions (3) to (6).
When configuring the projection zoom lens with the fourth lens group as the positive group, the conditions (1B) and (2B) are satisfied, and further, by satisfying one or more of the conditions (3B) to (6B), The roles played by the conditions (1) to (6) can be made to function similarly.
Before giving a specific example of a zoom lens, a mode of a projector apparatus will be briefly described with reference to FIG.
The projector apparatus 1 shown in FIG. 29 is an example in which a DMD that is a micromirror device is employed as the light valve 3.
The projector device 1 includes an illumination system 2, a DMD 3 that is a light valve, and a projection zoom lens 4. The illumination system 2 is an example of what is described above as “illumination box”.
As the projection zoom lens 4, one described in any one of claims 1 to 4, specifically, any one of Examples 1 to 3 and 5 to 14 is used.
The “light of three colors RGB” is temporally separated from the illumination system 2 and irradiated to the DMD 3, and the tilt of the micromirror corresponding to each pixel is controlled at the timing when each color light is irradiated.
In this way, the “image to be projected” is displayed on the DMD 3, and the light whose intensity is modulated by the image is enlarged by the projection zoom lens 4 and enlarged and projected on the screen 5.
The tilt angle of the micromirror is about ± 10 degrees, and the effective reflected light (effective light) and the invalid reflected light (ineffective light) are switched by switching the tilt angle.
When a micromirror device is used as a light valve, the projection zoom lens needs to capture the effective light satisfactorily and not capture invalid light as much as possible.
In order to meet this need, the projection zoom lens is preferably arranged in the “normal direction of the image display surface on which micromirrors are arrayed”.
In such an arrangement of the projection zoom lens, the light source of the illumination system needs to be installed adjacent to the projection zoom lens.
Therefore, it is necessary to reduce the lens diameter on the light valve side of the projection zoom lens so that the reduction side portion of the projection zoom lens does not block the illumination light with respect to the image display surface.
The illumination system 2 includes a light source 21, a condenser lens CL, an RGB color wheel CW, and a mirror M, and it is necessary to “ensure a certain amount of space” for arranging the light source 21.
For this reason, it is necessary to increase the incident angle of the illumination light incident on the DMD 3 from the illumination system 2 to some extent.
Due to the above-described relationship between the space between the projection zoom lens 4 and the illumination system 2, it is necessary to secure the back focus of the projection zoom lens 4 to some extent.
The illumination system 2 includes a light source 21, a condenser lens CL, an RGB color wheel CW, and a mirror M, and it is necessary to “ensure a certain amount of space” for arranging the light source 21.
For this reason, it is necessary to increase the incident angle of the illumination light incident on the DMD 3 from the illumination system 2 to some extent.
Due to the above-described relationship between the space between the projection zoom lens 4 and the illumination system 2, it is necessary to secure the back focus of the zoom lens 4 to some extent.
The condenser lens CL, the RGB color wheel CW and the mirror M constitute an “illumination optical system”.
In the zoom lenses for projection of Examples 1 to 14, the third lens group G3 to the fifth lens group G5 move to the enlargement side upon zooming from the wide-angle end to the telephoto end.
Accordingly, a sufficiently large back focus is ensured even during zooming.
In the following, 14 specific examples of the projection zoom lens according to the present invention will be described.
The meanings of symbols in each embodiment are as follows.
F: Focal length of the entire optical system
Fno: numerical aperture R: radius of curvature (“paraxial radius of curvature” for aspheric surfaces)
D: Surface spacing Nd: Refractive index Vd: Abbe number
BF: Back focus.
The aspherical surface is represented by the following well-known expression.
^{X = (H 2 / R)} / [1+ {1-K (H / r) 2} 1/2]
+ C4 · H ^{4} + C6 · H ^{6} + C8 · H ^{8} + C10 · H ^{10} +.
In this equation, X is “displacement in the direction of the optical axis at the position of the height H from the optical axis with respect to the surface vertex”, K is the “conical coefficient”, C4, C6, C8, C10. Aspheric coefficient.
"Example 1"
The projection zoom lens of Example 1 is shown in FIG.
As shown in FIG. 1, the first lens group G1 includes lenses L11 to L13, and the second lens group G2 includes lenses L21 to L24.
The third lens group G3 is composed of one lens L31, and the fourth lens group G4 is composed of two lenses L41 and L42.
The fifth lens group G5 is composed of four lenses L51 to L54.
As described above, a DMD is assumed as the light valve, and the DMD has a cover glass CG.
During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.
The first lens group G1 is a negative group, and includes a negative meniscus lens L11 that is convex on the enlargement side, a negative lens L12 that has a concave surface on the enlargement side, and a negative meniscus lens L13 that is concave on the reduction side.
The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 convex on the reduction side, and a negative meniscus lens L24 concave on the enlargement side.
The positive meniscus lens L23 and the negative meniscus lens L24 are cemented.
The third lens group G3 is a positive group and includes a single biconvex lens L31.
The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 that is convex on the enlargement side, and a positive meniscus lens L42 that is convex on the enlargement side.
The fifth lens group G5 is a negative group, and includes a negative meniscus lens L51 that is convex on the enlargement side, a biconvex lens L52, a negative meniscus lens L53 that is concave on the enlargement side, and a biconvex lens L54 (negative-positive-negative-positive). ).
The negative meniscus lens L51 and the biconvex lens L52 are cemented.
In the description of Examples 1 to 14, “biconvex lens” is one form of positive lens, and “biconcave lens” is one form of negative lens.
The focal length: F range, F number, half angle of view at the wide angle end: ωw of the entire system in Example 1 are as follows.
F = 13.0 to 19.6 mm, Fno = 2.55 to 3.34, ωw = 42.1 °
The data of the examples are shown in Table 1.
In Table 1, the surface number is the number of the surface counted from the enlarged side, and includes the surface of the aperture stop (surface number: 20 in the table) and the surface of the cover glass CG (surface numbers: 28, 29 in the table). .
“INF” in the table indicates that the radius of curvature is infinite. Furthermore, “*” indicates that the surface with this symbol is “aspherical surface”.
These matters are the same in each of the following embodiments.
"Aspherical data"
The aspherical data is shown in Table 2.
In Table 1, S6, S13, S15, and S20 represent lens group intervals that change during zooming.
Table 3 shows the distance between the lens groups when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.
"Parameter values for each condition"
Table 4 shows parameter values of the conditions (1) to (6).
FIG. 2 shows aberration diagrams of Example 1.
The upper part of FIG. 2 shows the aberration at the “wide angle end (indicated as wide angle)”, the middle part at “intermediate focal length (indicated as intermediate)”, and the lower part at “telephoto end (indicated as telephoto)”.
In the aberration diagrams at each stage, the left diagram is “spherical aberration”, the middle diagram is “astigmatism”, and the right diagram is “distortion aberration”.
R, G, and B in the “spherical aberration” diagram represent wavelengths: R = 625 nm, G = 550 nm, and B = 460 nm, respectively.
In the “astigmatism” diagram, “T” indicates tangential and “S” indicates sagittal rays.
Astigmatism and distortion are shown for a wavelength of 550 nm.
These indications in the aberration diagrams are the same in the aberration diagrams of Examples 2 to 14 below.
"Example 2"
The projection zoom lens of Example 2 is shown in FIG.
As shown in FIG. 3, the first lens group G1 includes lenses L11 to L13, and the second lens group G2 includes lenses L21 to L24.
The third lens group G3 includes one lens L31, the fourth lens group G4 includes lenses L41 and L42, and the fifth lens group G5 includes lenses L51 to L54.
During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.
The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative meniscus lens L13 concave on the reduction side.
The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 convex on the reduction side, and a negative meniscus lens L24 concave on the enlargement side.
The positive meniscus lens L32 and the negative meniscus lens L24 are cemented.
The third lens group G3 is a positive group and includes a single biconvex lens L31.
The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 that is convex on the enlargement side, and a biconvex lens L42 that has a large curvature on the convex surface on the enlargement side.
The fifth lens group G5 is a negative group, and includes a biconcave lens L51, a biconvex lens L52, a negative meniscus lens L53 concave on the enlargement side, and a biconvex lens L54.
The biconcave lens L51 and the biconvex lens L52 are cemented.
In Example 2, the focal length of the entire system: F range, F number, and half angle of view at the wide-angle end: ωw are as follows.
F = 13.0 to 19.6 mm, Fno = 2.55 to 3.34, ωw = 42.1 °
The data of Example 2 is shown in Table 5.
"Aspherical data"
Table 6 shows the aspherical data.
Table 7 shows lens group intervals: S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.
"Parameter values for each condition"
Table 8 shows parameter values of the conditions (1) to (6).
FIG. 4 is an aberration diagram of Example 2 similar to FIG.
"Example 3"
The projection zoom lens of Example 3 is the one shown in FIG.
As shown in FIG. 5, the first lens group G1 is composed of lenses L11 to L13, and the second lens group G2 is composed of lenses L21 to L24.
The third lens group G3 includes a lens L31, the fourth lens group G4 includes lenses L41 and L42, and the fifth lens group G5 includes lenses L51 to L54.
During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.
The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative negative meniscus lens L13 on the reduction side.
The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 convex on the reduction side, and a negative meniscus lens L24 concave on the enlargement side.
The positive meniscus lens L23 and the negative meniscus lens L24 are cemented.
The third lens group G3 is a positive group and includes a single biconvex lens L31.
The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 and a biconvex lens L42 that are convex on the enlargement side.
The fifth lens group G5 is a negative group, and includes a negative meniscus lens L51 that is convex on the enlargement side, a biconvex lens L52, a negative meniscus lens L53 that is concave on the enlargement side, and a biconvex lens L54.
The negative meniscus lens L51 and the biconvex lens L52 are cemented.
In Example 3, the focal length of the entire system: the range of F, the F number, and the half field angle at the wide angle end: ωw are as follows.
F = 13.0 to 19.6 mm, Fno = 2.55 to 3.34, ωw = 42.1 °
The data of Example 3 is shown in Table 9.
"Aspherical data"
Table 10 shows the aspheric data.
Table 11 shows the lens group intervals S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.
"Parameter values for each condition"
Table 12 shows parameter values of the conditions (1) to (6).
FIG. 6 is an aberration diagram of Example 3 similar to FIG.
Example 4
The projection zoom lens of Example 4 is shown in FIG.
As shown in FIG. 7, the first lens group G1 includes lenses L11 to L13, and the second lens group G2 includes lenses L21 to L24.
The third lens group G3 includes lenses L31 and L32, the fourth lens group G4 includes lens L41, and the fifth lens group G5 includes lenses L51 to L54.
During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.
The first lens group G1 is a negative group, and includes a negative meniscus lens L11 that is convex on the enlargement side, a negative meniscus lens L12 that is concave on the enlargement side, and a negative meniscus lens L13 that is concave on the reduction side.
The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 convex on the reduction side, and a negative meniscus lens L24 concave on the enlargement side.
The positive meniscus lens L23 and the negative meniscus lens L24 are cemented.
The third lens group G3 is a positive group, and includes a biconvex lens L31 and a positive meniscus lens L32 convex on the enlargement side.
The fourth lens group G4 is a positive group and includes a biconvex lens L41.
The fifth lens group G5 is a negative group, and includes a negative meniscus lens L51 that is concave on the reduction side, a biconvex lens L52, a negative meniscus lens L53 that is concave on the enlargement side, and a biconvex lens L54.
The negative meniscus lens L51 and the biconvex lens L52 are cemented.
In Example 4, the focal length of the entire system: F range, F number, and half angle of view at the wide angle end: ωw are as follows.
F = 13.0 to 19.6 mm, Fno = 2.55 to 3.34, ωw = 42.1 °
The data of Example 4 is shown in Table 13.
"Aspherical data"
Table 14 shows the aspheric data.
Table 15 shows lens group intervals S6, S13, S17, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.
"Parameter values for each condition"
Table 16 shows parameter values of the conditions (1) to (4).
FIG. 8 shows aberration diagrams of Example 4 according to FIG.
"Example 5"
The projection zoom lens of Example 5 is shown in FIG.
As shown in FIG. 9, the first lens group G1 is composed of lenses L11 to L13, and the second lens group G2 is composed of lenses L21 to L24.
The third lens group G3 is composed of one lens L31, the fourth lens group G4 is composed of one lens L41, and the fifth lens group G5 is composed of lenses L51 to L54.
During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.
The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative meniscus lens L13 concave on the reduction side.
The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 convex on the reduction side, and a negative meniscus lens L24 concave on the enlargement side.
The positive meniscus lens L23 and the negative meniscus lens L24 are cemented.
The third lens group G3 is a positive group and includes a single biconvex lens L31.
The fourth lens group G4 is a positive group and includes a single biconvex lens L41.
The fifth lens group G5 is a negative group, and includes a biconcave lens L51, a biconvex lens L52, a negative meniscus lens L53 concave on the enlargement side, and a biconvex lens L54.
The biconvex lens L51 and the biconcave lens L52 are cemented.
In Example 4, the focal length of the entire system: F range, F number, and half angle of view at the wide angle end: ωw are as follows.
F = 13.0 to 19.6 mm, Fno = 2.55 to 3.35, ωw = 42.1 °
The data of Example 5 is shown in Table 17.
"Aspherical data"
Table 18 shows the aspheric data.
Table 19 shows lens group intervals S6, S13, S15, and S18 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.
"Parameter values for each condition"
Table 20 shows parameter values of the conditions (1) to (6).
FIG. 10 is an aberration diagram of Example 5 similar to FIG.
"Example 6"
The projection zoom lens of Example 6 is the one shown in FIG.
As shown in FIG. 11, the first lens group G1 includes lenses L11 to L13, and the second lens group G2 includes lenses L21 to L24.
The third lens group G3 includes one lens L31, the fourth lens group G4 includes L41 and L42, and the fifth lens group G5 includes lenses L51 to L54.
During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.
The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative meniscus lens L13 concave on the reduction side.
The second lens group G2 is a negative group, and includes a biconvex lens L21, a negative meniscus lens L22 concave on the reduction side, a positive meniscus lens L23, and a negative meniscus lens L24.
The positive meniscus lens L23 is “convex on the reduction side” and the negative meniscus lens L24 is “concave on the enlargement side”. These positive and negative meniscus lenses L23 and L24 are cemented.
The third lens group G3 is a positive group and includes a single biconvex lens L31.
The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 and a biconvex lens L42 that are convex on the enlargement side.
The fifth lens group G5 is a positive group, and includes a biconcave lens L51, a biconvex lens L52, a negative meniscus lens L53 concave on the enlargement side, and a biconvex lens L54.
The biconcave lens L51 and the biconvex lens L52 are cemented.
In Example 6, the focal length of the entire system: the range of F, the F number, and the half angle of view at the wide-angle end: ωw are as follows.
F = 13.0 to 19.6 mm, Fno = 2.58 to 3.24, ωw = 42.1 °
The data of Example 6 is shown in Table 21.
"Aspherical data"
Table 22 shows the aspherical data.
Table 23 shows lens group intervals S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.
"Parameter values for each condition"
Table 24 shows the parameter values of the conditions (1) to (6).
FIG. 12 is an aberration diagram of Example 6 similar to FIG.
"Example 7"
The projection zoom lens of Example 7 is shown in FIG.
As shown in FIG. 13, the first lens group G1 includes lenses L11 to L13, and the second lens group G2 includes lenses L21 to L24.
The third lens group G3 includes one lens L31, the fourth lens group G4 includes lenses L41 and L42, and the fifth lens group G5 includes lenses L51 to L54.
During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.
The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative negative meniscus lens L13 on the reduction side.
The second lens group G2 is a negative group, and includes a biconvex lens L21, a negative meniscus lens L22 concave on the reduction side, a positive meniscus lens L23, and a negative meniscus lens L24.
The positive meniscus lens L23 is “convex on the reduction side”, the negative meniscus lens L24 is concave on the enlargement side, and these positive and negative meniscus lenses L23 and L24 are cemented.
The third lens group G3 is a positive group and includes a single biconvex lens L31.
The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 and a biconvex lens L42 that are convex on the enlargement side.
The fifth lens group G5 is a positive group, and includes a biconcave lens L51, a biconvex lens L52, a negative meniscus lens L53 concave on the enlargement side, and a biconvex lens L54.
The biconcave lens L51 and the biconvex lens L52 are cemented.
In Example 7, the focal length of the entire system: the range of F, the F number, and the half angle of view at the wide angle end: ωw are as follows.
F = 13.0 to 19.6 mm, Fno = 2.58 to 3.24, ωw = 42.1 °
The data of Example 7 is shown in Table 25.
"Aspherical data"
Table 26 shows the aspherical data.
Table 27 shows the lens group spacings S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.
"Parameter values for each condition"
Table 28 shows parameter values of the conditions (1) to (6).
FIG. 14 is an aberration diagram of Example 7 similar to FIG.
The projection zoom lens of Example 8 is shown in FIG.
As shown in FIG. 15, the first lens group G1 is composed of lenses L11 to L13, and the second lens group G2 is composed of lenses L21 to L24.
The third lens group G3 includes one lens L31, the fourth lens group G4 includes lenses L41 and L42, and the fifth lens group G5 includes lenses L51 to L54.
During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.
The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative meniscus lens L13 concave on the reduction side.
The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 having a convex surface on the reduction side, and a negative meniscus lens L24 having a concave surface on the enlargement side.
The positive meniscus lens L23 and the negative meniscus lens L24 are cemented.
The third lens group G3 is a positive group and includes a single biconvex lens L31.
The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 and a biconvex lens L42 that are convex on the enlargement side.
The fifth lens group G5 is a negative group, and includes a negative meniscus lens L51 that is convex on the enlargement side, a biconvex lens L52, a negative meniscus lens L53 that is concave on the enlargement side, and a biconvex lens L54.
The negative meniscus lens L51 and the biconvex lens L52 are cemented.
Although the refractive power of the fifth lens group G5 is negative, this negative refractive power is weak.
In Example 8, the focal length of the entire system: the range of F, the F number, and the half angle of view at the wide angle end: ωw are as follows.
F = 14.2 to 21.1 mm, Fno = 2.55 to 3.34, ωw = 39.6 °
The data of Example 8 is shown in Table 29.
"Aspherical data"
Table 30 shows the aspherical data.
Table 31 shows lens group intervals S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.
"Parameter values for each condition"
Table 32 shows parameter values of the conditions (1) to (6).
FIG. 16 is an aberration diagram of Example 8 similar to FIG.
"Example 9"
The projection zoom lens of Example 9 is shown in FIG.
As shown in FIG. 1, the first lens group G1 includes lenses L11 to L13, and the second lens group G2 includes lenses L21 to L24.
The third lens group G3 includes one lens L31, the fourth lens group G4 includes lenses L41 and L42, and the fifth lens group G5 includes lenses L51 to L54.
During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.
The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative meniscus lens L13 concave on the reduction side.
The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 convex on the reduction side, and a negative meniscus lens L24 concave on the enlargement side.
The positive meniscus lens L23 and the negative meniscus lens L24 are cemented.
The third lens group G3 is a positive group and includes a single biconvex lens L31.
The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 and a biconvex lens L42 that are convex on the enlargement side.
The fifth lens group G5 is a negative group having a weak refractive power, and includes a negative meniscus lens L51 convex to the enlargement side, a biconvex lens L52, a negative meniscus lens L53, and a biconvex lens L54.
The negative meniscus lens L53 is “concave on the enlargement side”. The negative meniscus lens L51 and the biconvex lens L52 are cemented.
The focal length of the entire system in Example 9: F range, F number, and half angle of view at the wide angle end: ωw are as follows.
F = 13.8 to 20.5 mm, Fno = 2.55 to 3.34, ωw = 40.4 °
The data of Example 9 is shown in Table 33.
"Aspherical data"
Table 34 shows the aspherical data.
Table 35 shows lens group intervals S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.
"Parameter values for each condition"
Table 36 shows parameter values of the conditions (1) to (6).
FIG. 18 is an aberration diagram of Example 9 similar to FIG.
"Example 10"
The projection zoom lens of Example 10 is shown in FIG.
As shown in FIG. 19, the first lens group G1 is composed of lenses L11 to L13, and the second lens group G2 is composed of lenses L21 to L24.
The third lens group G3 is composed of a single lens L31, the fourth lens group G4 is composed of lenses L41 and L42, and the fifth lens group G5 is composed of lenses L51 to L54.
During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.
The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative meniscus lens L13 concave on the reduction side.
The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 convex on the reduction side, and a negative meniscus lens L24 concave on the enlargement side.
The positive meniscus lens L23 and the negative meniscus lens L24 are cemented.
The third lens group G3 is a positive group and includes a single biconvex lens L31.
The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 and a biconvex lens L42 that are convex on the enlargement side.
The fifth lens group G5 is a negative group having a weak refractive power, and includes a negative meniscus lens L51 having a convex surface on the enlargement side, a biconvex lens L52, a negative meniscus lens L53, and a biconvex lens L54.
The negative meniscus lens L53 is “concave on the enlargement side”, and the negative meniscus lens L51 and the biconvex lens L52 are cemented.
In Example 10, the focal length of the entire system: the range of F, the F number, and the half angle of view at the wide angle end: ωw are as follows.
F = 12.4 to 18.5 mm, Fno = 2.56 to 3.34, ωw = 43.3 °
The data of Example 10 is shown in Table 37.
"Aspherical data"
Table 38 shows the aspherical data.
Table 39 shows lens group intervals S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.
"Parameter values for each condition"
Table 40 shows parameter values of the conditions (1) to (6).
FIG. 20 is an aberration diagram of Example 10 similar to FIG.
The projection zoom lens of Example 11 is the one shown in FIG.
As shown in FIG. 21, the first lens group G1 includes lenses L11 to L13, and the second lens group G2 includes lenses L21 to L24.
The third lens group G3 includes one lens L31, the fourth lens group G4 includes lenses L41 and L42, and the fifth lens group G5 includes lenses L51 to L54.
During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.
The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative meniscus lens L13 concave on the reduction side.
The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 convex on the reduction side, and a negative meniscus lens L24 concave on the enlargement side.
The positive meniscus lens L23 and the negative meniscus lens L24 are cemented.
The third lens group G3 is a positive group and includes a single biconvex lens L31.
The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 and a biconvex lens L42 that are convex on the enlargement side.
The fifth lens group G5 is a negative group having a weak refractive power, and includes a negative meniscus lens L51 that is convex on the enlargement side, a biconvex lens L52, a negative meniscus lens L53, and a biconvex lens L54.
The negative meniscus lens L53 is “concave on the enlargement side”, and the negative meniscus lens L51 and the biconvex lens L52 are cemented.
In Example 11, the focal length of the entire system: F range, F number, and half angle of view at the wide angle end: ωw are as follows.
F = 11.8 to 17.6 mm, Fno = 2.56 to 3.34, ωw = 44.8 °
The data of Example 11 are shown in Table 41.
"Aspherical data"
Table 42 shows aspherical data.
Table 43 shows lens group intervals S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.
"Parameter values for each condition"
Table 44 shows parameter values of the conditions (1) to (6).
FIG. 22 shows aberration diagrams of Example 11 following FIG.
"Example 12"
The projection zoom lens of Example 12 is shown in FIG.
As shown in FIG. 23, the first lens group G1 includes lenses L11 and L12, and the second lens group G2 includes lenses L21 to L24.
The third lens group G3 is composed of lenses L31 and L32, the fourth lens group G4 is composed of lenses L41 to L44, and the fifth lens group G5 is composed of a single lens L51.
During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.
The first lens group G1 is a negative group, and includes a negative meniscus lens L11 that is convex on the enlargement side, and a negative lens L12 that is concave on the reduction side.
The second lens group G2 is a negative group, and includes a negative meniscus lens L21 that is convex on the enlargement side, a positive meniscus lens L22 that is convex on the enlargement side, a biconcave lens L23, and a biconvex lens L24.
The negative meniscus lens L21 and the positive meniscus lens L22 are cemented.
The third lens group G3 is a positive group, and includes a positive meniscus lens L31 and a biconvex lens L32 that are convex on the enlargement side.
The fourth lens group G4 is a negative group, and includes a biconcave lens L41, a biconvex lens L42, a negative meniscus lens L43 concave on the enlargement side, and a biconvex lens L44.
The biconcave lens L41 and the biconvex lens L42 are cemented.
The fifth lens group G5 is a negative group, and includes a single negative meniscus lens L51 that is concave on the enlargement side.
In Example 12, the focal length of the entire system: the range of F, the F number, and the half field angle at the wide angle end: ωw are as follows.
F = 12.3 to 17.9 mm, Fno = 2.56 to 3.34, ωw = 43.6 °
The data of Example 12 is shown in Table 45.
"Aspherical data"
Table 46 shows aspherical data.
Table 47 shows lens group intervals S4, S11, S16, and S23 when the projection distance is 1600 mm, at the wide-angle end, the middle, and the telephoto end.
"Parameter values for each condition"
Table 48 shows parameter values of the conditions (1) to (6).
FIG. 24 shows aberration diagrams of Example 12 according to FIG.
"Example 13"
The projection zoom lens of Example 13 is shown in FIG.
As shown in FIG. 25, the first lens group G1 includes lenses L11 and L12, and the second lens group G2 includes lenses L21 to L24.
The third lens group G3 is composed of lenses L31 and L32, the fourth lens group G4 is composed of lenses L41 and L42, and the fifth lens group G5 is composed of a single lens L51.
During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.
The first lens group G1 is a negative group, and includes a negative meniscus lens L11 that is convex on the enlargement side, and a negative lens L12 that is concave on the reduction side.
The second lens group G2 is a negative group, and includes a negative meniscus lens L21 that is convex on the enlargement side, a positive meniscus lens L22 that is convex on the enlargement side, a biconcave lens L23, and a biconvex lens L24.
The negative meniscus lens L21 and the positive meniscus lens L22 are cemented.
The third lens group G3 is a positive group, and includes a positive meniscus lens L31 and a biconvex lens L32 that are convex on the enlargement side.
The fourth lens group G4 is a negative group, and includes a biconcave lens L41, a biconvex lens L42, a negative meniscus lens L43 concave on the enlargement side, and a biconvex lens L44.
The biconcave lens L41 and the biconvex lens L42 are cemented.
The fifth lens group G5 is a positive group and includes a single biconvex lens L51.
In Example 13, the focal length of the entire system: the range of F, the F number, and the half angle of view at the wide angle end: ωw are as follows.
F = 12.3 to 17.9 mm, Fno = 2.56 to 3.34, ωw = 43.6 °
The data of Example 13 are shown in Table 49.
"Aspherical data"
Table 50 shows aspherical data.
Table 51 shows lens group intervals S4, S11, S16, and S23 when the projection distance is 1600 mm, at the wide-angle end, the middle, and the telephoto end.
"Parameter values for each condition"
Table 52 shows parameter values of the conditions (1) to (6).
FIG. 26 shows aberration diagrams of Example 13 following FIG.
"Example 14"
The projection zoom lens of Example 14 is shown in FIG.
As shown in FIG. 27, the first lens group G1 includes lenses L11 to L13, and the second lens group G2 includes lenses L21 to L24.
The third lens group G3 includes one lens L31, the fourth lens group G4 includes lenses L41 and L42, and the fifth lens group G5 includes lenses L51 to L54.
During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.
The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative meniscus lens L13 concave on the reduction side.
The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 convex on the reduction side, and a negative meniscus lens L24 concave on the enlargement side.
The positive meniscus lens L23 and the negative meniscus lens L24 are cemented.
The third lens group G3 is a positive group and includes a single biconvex lens L31.
The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 and a planoconvex positive lens L42 that are convex on the enlargement side.
The fifth lens group G5 is a negative group, and includes a planoconcave negative lens L51, a biconvex lens L52, a negative meniscus lens L53 concave on the enlargement side, and a biconvex lens L54.
The plano-concave negative lens L51 and the biconvex lens L52 are cemented.
In Example 14, the focal length of the entire system: the range of F, the F number, and the half field angle at the wide angle end: ωw are as follows.
F = 17.4 to 26 mm, Fno = 2.55 to 3.33, ωw = 34.0 °
The data for Example 14 are shown in Table 53.
"Aspherical data"
Table 54 shows the aspherical data.
Table 55 shows lens group intervals S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.
"Parameter values for each condition"
Table 56 shows parameter values of the conditions (1) to (6).
FIG. 28 shows aberration diagrams of Example 14 according to FIG.
As shown in the aberration diagrams, in the projection zoom lenses according to the respective embodiments, various aberrations are corrected at a high level, and spherical aberration, astigmatism, curvature of field, lateral chromatic aberration, and distortion are sufficiently corrected.
Each of the projection zoom lenses shown in Examples 1 to 14 has a five-lens group configuration in which the first to fifth lens groups are arranged from the enlargement side toward the reduction side.
The first lens group has a negative refractive power, the second lens group has a negative refractive power, and the third lens group has a positive refractive power.
And the said conditions: (1)-(6) are satisfied.
In Example 12 and Example 13, the fourth lens group is a “negative group”, and the parameters of the conditions (1) to (6) satisfy the conditions (1A) to (6A).
In other examples except Examples 12 and 13, the fourth lens group is a “positive group”, and the parameters of the conditions (1) to ( 6 ) satisfy the conditions (1B) to ( 6B ). doing.
In addition, the projection zoom lens of each embodiment has a wide angle of view where the half angle of view at the wide angle end is larger than 34 degrees.
In addition, both a large back focus Bf and a short focal length Fw are secured, and aberration correction at the time of zooming is good and compact.