JPH1123963A - Image-formation lens system and recording optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image-formation lens system and a recording optical device capable of contriving miniaturization, obtaining large image plane size, making an aperture ratio large and obtaining high resolution. SOLUTION: In this image-formation lens system 1, a 1st lens group 2, a 2nd lens group 3 and a 3rd lens group 4 are arranged in this order from an enlarging side A and a diaphragm 5 is arranged so as to coincide with the synthetic focal position 5a of the respective lenses. By constituting the 1st lens gorup 2 of plural lenses having negative power, the large image plane size is obtained. By constituting the 2nd lens group 3 of plural lenses having a concave surface facing toward the diaphragm 5, the aperture ratio is made large. By constituting the 3rd lens group 4 of plural lenses having positive power, a semiconductor laser array can be used as a light source and the high resolution is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging lens system suitable for a recording optical device such as a copying machine or a printer using a semiconductor laser array having a plurality of independently controllable light emitting portions, and using the same. The present invention relates to a recording optical device.

[0002]

2. Description of the Related Art Conventional imaging lens systems are disclosed in, for example, Japanese Patent Application Laid-Open Nos. 3-72310 and 62-5251.
No. 6 is disclosed.

A conventional imaging lens system disclosed in Japanese Patent Application Laid-Open No. 3-72310 is used for an exposure apparatus in manufacturing a printed circuit board, and is constituted by a telecentric lens system. That is, this imaging lens system has a first power having a positive power with the convex surface facing the object side.
A lens, a second lens arranged on the image side of the first lens and having a convex surface facing the object side and having positive power, and a negative lens arranged on the image side of the second lens and having a concave surface facing the image side. A front lens group including a third lens having a negative power, a fourth lens having a negative power, which is disposed on the image side of the front lens group and has a concave surface facing the object side, and an image side of the fourth lens. A fifth lens having a positive power with the concave surface facing the image side, a sixth lens having a positive power with the convex surface facing the image side, A rear lens group including a seventh lens disposed on the image side of the sixth lens and having a positive power with the convex surface facing the object side, and a front lens so as to coincide with a front combined focal position of the rear lens group. Group and a diaphragm arranged between the rear lens group. . According to this imaging lens system, by employing a telecentric lens system, the dimensional accuracy of the image is increased, the distance between the object and the image is increased as compared with the screen size, and the aperture ratio is increased to improve the resolution. be able to.

A conventional imaging lens system disclosed in Japanese Patent Application Laid-Open No. 62-52516 is used for micrographics for reducing an engineering drawing to a micro-image size, and is arranged with an interval. A first lens group composed of a pair of meniscus lenses, a second lens group composed of a double lens and a biconvex lens cemented to each other, a third lens group composed of a plano-convex lens and a double lens cemented to each other, It comprises a fourth lens group composed of double lenses joined together, and an aperture stop arranged between the second lens group and the third lens group. According to this imaging lens system, a super-wide-angle lens having a half angle of view of 33 degrees can be provided.

On the other hand, in recording optical devices such as an optical printer and a digital copying machine of an electrophotographic system, improvement in image quality is required in recent years, and higher precision of a printed image, that is, improvement in resolution and the like is progressing.

[0006] As such a conventional recording optical device,
For example, there is one disclosed in JP-A-1-152683. This recording optical device is a laser beam scanner using a semiconductor laser array in which semiconductor lasers are arranged one-dimensionally as a light source. Here, a sufficient amount of light is obtained because the semiconductor laser array is used as a light source, and a light emitting pattern is projected onto a recording surface by an optical system, so that a movable portion is not required. Further, since a semiconductor laser which is monochromatic light is used as a light source, an optical system corresponding to a single wavelength may be used, so that there is an advantage that correction of chromatic aberration is unnecessary.

In an optical system of such a recording optical device, a light emission pattern on a semiconductor laser array is enlarged and projected onto a photoreceptor at a low magnification of about 1 to 8 and a relatively small distance. Therefore, in order to realize high image quality, various aberrations must be sufficiently corrected in order for the optical system to have a resolving power of 100 lines / mm or more. In order to obtain this, the opening on the reduction side which is the semiconductor laser array side needs to be as large as possible. Specifically, when the desired screen size is 300 mm or more on the enlargement side, the F-number on the reduction side is 3
In order to meet the requirement of further reducing the distance between the object and the image, the total length of the lens system must be kept short.

[0008]

However, Japanese Patent Laid-Open No. 3-7 / 1990
According to the conventional imaging lens system disclosed in Japanese Patent No. 2310, the screen size required in a recording optical apparatus is considerably larger than the screen size of such an exposure apparatus. In order to satisfy the screen size required for the apparatus, a huge lens is required, and there is a problem that the recording optical apparatus becomes large.

According to a conventional imaging lens system disclosed in Japanese Patent Application Laid-Open No. 62-52516, a lens system for micrographics has a sufficient screen size, but requires a small aperture ratio. There is a problem that resolution cannot be obtained.

Further, according to the conventional recording optical apparatus disclosed in Japanese Patent Application Laid-Open No. 1-152683, a sufficient amount of light can be obtained because a semiconductor laser array is used as a light source. There is a problem that can not be obtained.

Accordingly, an object of the present invention is to reduce the size,
An object of the present invention is to provide an image forming lens system and a recording optical device which can obtain a high resolution with a large screen size, a large aperture ratio and a high resolution.

[0012]

In order to achieve the above object, the present invention uses a predetermined number of lenses and enlarges or reduces incident light from a reduction side or an enlargement side to form an image on an image plane. In the imaging lens system, a first lens group including a plurality of lenses having negative power on the enlargement side, an aperture arranged to coincide with a combined focal position of the predetermined number of lenses, and the first lens A second lens group including a plurality of lenses disposed on the reduction side of the group and having concave surfaces facing the aperture on both sides of the aperture; and a second lens group disposed on the reduction side of the second lens group and having a positive power. There is provided an imaging lens system including a third lens group including a plurality of lenses.

[0013] In order to achieve the above object, the present invention provides a semiconductor laser array having a plurality of independently controllable light emitting units, and the semiconductor laser arranged on a reduction side or an enlargement side using a predetermined number of lenses. An imaging lens system for enlarging or reducing incident light from the plurality of light emitting units of the array to form an image on an imaging surface, wherein the imaging lens system has a plurality of negative powers on the enlargement side. A first lens group including a lens, a stop arranged so as to coincide with the combined focal position of the predetermined number of lenses, and a stop arranged on the reduction side of the first lens group; A second lens group including a plurality of lenses each having a concave surface facing the lens, and a third lens group disposed on the reduction side of the second lens group and including a plurality of lenses having positive power. Recording optics To provide a location.

[0014]

FIG. 1 shows an imaging lens system according to a first embodiment of the present invention. This imaging lens system 1
The ten single lenses are used to magnify the incident light from the reduction side B to form an image on an imaging surface (not shown). The first lens group 2, the second lens group 3, and the A third lens group 4 is provided, and a stop 5 is provided so as to coincide with the combined focal position 5a of each lens.

The first lens group 2 includes a first lens 11 having a negative power with a convex surface facing the enlargement side A, a second lens 12 having a positive power with a convex surface facing the enlargement side A, and a magnifying side. A third lens 13 having a negative power and a convex surface facing A
The angle of view is configured to be 20 to 30 degrees.

The second lens group 3 includes a fourth lens 14 having a negative power with a convex surface facing the enlargement side A, a fifth lens 15 having a positive power with a convex surface facing the enlargement side A, and a magnifying side. A sixth lens 16 having a negative power and a concave surface facing A
And a seventh lens 17 having a negative power and a convex surface directed to the reduction side B, and configured such that the brightness of light formed on the image forming surface is F = 2 to 3.

The third lens group 4 includes an eighth lens 18 having a positive power with a convex surface facing the reduction side B, a ninth lens 19 having a positive power with a convex surface facing the reduction side B, and a Tenth lens 2 having a positive power and a convex surface facing B
0 and is telecentric.

The diaphragm 5 includes a sixth lens 16 and a seventh lens 1
7 are arranged.

The imaging lens system 1 includes first and second
When the refractive indices of the third and third lenses 11, 12, and 13 are n ₁ , n ₂ , and n ₃ , the combined focal length of the entire system is f, and the total length of the lens is OAL, n ₂ > n ₁ (1) n ₂ > n ₃ (2) 2.1f <OAL <3.2f (3) Each condition (1), (2), (3) is satisfied. In the embodiments described later, the same reference numerals are used for those having the same meaning as described above, and the description is omitted.

The above conditions (1) and (2) regulate the relationship between the respective refractive indices of the retro lens of the front group consisting of the first lens group 2, and the second lens ( The positive lens 12 has a higher refractive index than the first and third lenses 11 and 13 having negative power. The above condition (3) is a condition for regulating the overall length of the lens, and if the lens system is compact, it is convenient to reduce the size of the device.However, below the lower limit, the field curvature and astigmatism increase, Furthermore, it becomes impossible to remove off-axis sagittal flare well. If the upper limit is exceeded, both the lens diameter and the overall length become large, resulting in an increase in size.

Next, the operation of the imaging lens system 1 having the above configuration will be described. The imaging lens system 1 according to the present embodiment is of a so-called retrofocus type, and includes a second lens group 3 and a third
The imaging lens system of the rear group composed of the lens group 4 is a modified double Gaussian type. In this type of lens system, the first
To obtain a wide angle of view by the concave surfaces of the two sixth lens 16 and the seventh lens 17 in the middle of the modified double Gaussian lens system of the rear group by the divergent action of the retro system of the front group consisting of the lens group 2 The diverging action is compensated for, and the radii of curvature r ₁₂ and r ₁₄ of these biconcave surfaces, which tend to be the strongest among all lens systems, can be lengthened, and spherical aberrations such as meridional coma, The occurrence of sagittal flare can be reduced.

Normally, to achieve a wide angle of view on the enlargement side A in order to obtain a large screen size, it is possible to use a diffusion lens having a large negative power on the enlargement side as a retro system. The resulting aberrations also increase, and it becomes difficult to correct them by the rear group of imaging lens systems including the second lens group 3 and the third lens group 4. Therefore, in the retro system of the front group, a negative lens, a positive lens, and a negative lens are arranged in order from the enlargement side in order to suppress the occurrence of aberration caused by enhancing the diverging action by using a diffusion lens. That is, negative lenses 11 and 13 are used as diffusion lenses.
By dividing the negative power by using two lenses, the generated aberration is reduced, and a positive lens 12 having a higher refractive index than the negative lenses 11 and 13 is provided between the negative lenses 11 and 13. , Negative lenses 11 and 13
Is a retro-type arrangement that easily cancels out the aberration generated by the above. When one negative lens having a large divergence action is used as the diffusion lens, the radius of curvature of the surface of the negative lens must be reduced, and the amount of aberration generated by the negative lens increases.
In the case where two negative lenses are used, the aberration generated in the negative lens can be reduced by dispersing the diverging function. However, this aberration is corrected by a modified double Gaussian lens system in the rear group. It becomes difficult. Therefore,
As described above, by inserting a positive lens between the negative lenses, the aberration generated by the negative lens is canceled out, and a diffusion lens with small aberration that can be corrected by the modified double Gaussian lens system in the rear group Becomes possible.

When a laser array is used, the light emitted from each laser is generally parallel to each other, so that the reduction side B must be telecentric, and at least the lens group provided on the reduction side B Two (three in this embodiment) lenses having a positive refractive power are included. If this group is, for example, one, it is difficult to bend off-axis chief rays and suppress aberrations so as to be telecentric.

According to the imaging lens system 1 according to the first embodiment, the following effects can be obtained. (A) Since the diverging effect is enhanced in the first lens group 2, a wide angle of view of 20 to 30 degrees can be obtained, and the screen size can be increased. (B) Since the negative power is dispersed in the first lens group 2, the generated aberration can be reduced. Further, since the positive lens 12 is disposed between the negative lenses 11 and 13, the aberration generated by the negative lenses 11 and 13 is canceled. As a result, it is possible to reduce aberration. (C) Since the second lens group 3 is a modified double Gaussian lens system, bright light of F = 2 to 3 can be obtained on the imaging plane. (D) Since the positive power is dispersed in the third lens group 4, the configuration of telecentricity becomes easy, and a semiconductor laser array capable of obtaining high resolution can be used as a light source.

FIG. 2 shows an imaging lens system according to a second embodiment of the present invention. In the imaging lens system 1, in the first embodiment, the fourth lens 14 of the second lens group 3 is a positive lens having a positive surface with a convex surface directed to the enlargement side A, and n ₂ > n ₁ . (1) n ₂ > n ₃ ... (2) 2.5f <OAL <3.2f... (3), each of which satisfies the conditions (1), (2), and (3). Otherwise, the configuration is the same as that of the first embodiment.

FIG. 3 shows an imaging lens system according to a third embodiment of the present invention. In the imaging lens system 1, in the first embodiment, an eighth lens 18 having a negative power with a concave surface facing the reduction side B is added to the second lens group 3, and the third lens group 4 is reduced. The ninth lens 19 has a positive power with the convex surface directed to the side B, and the tenth lens 20 has a positive power with the convex surface directed to the reduction side B. n ₂ > n ₁ (1) n ₂ > n ₃ (2) 2.1f <OAL <3.2f (3) The conditions (1), (2), and (3) are satisfied. The configuration is the same as that of the embodiment.

FIG. 4 shows an imaging lens system according to a fourth embodiment of the present invention. The imaging lens system 1 uses twelve single lenses to magnify incident light from the reduction side B and form an image on an imaging plane (not shown). 2, the second lens group 3 and the third lens group 4 are arranged, and the diaphragm 5 is provided so as to coincide with the combined focal position 5a of each lens. When the refractive index of the second lens is n _j , the total lens length is OAL, and the distance between object images (total optical path length) is TT, n ₂ > n ₁ (1) n ₂ > n ₃ (2) 8f <OAL <3.8f (3) 0.045 <TT / (OAL · f) <0.065 (4) Conditions (1), (2), (3) and (4) are satisfied. It is configured to be.

As in the first embodiment, the first lens group 2 includes a first lens 11 having negative power, a second lens 12 having positive power, and a third lens 12 having negative power.
And a lens 13.

The second lens group 3 includes a fourth lens 14 having a negative power having a convex surface directed to the enlargement side A, a fifth lens 15 having a negative power having a convex surface directed to the enlargement side A, and a magnifying side. A sixth lens 16 having a positive power with the convex surface facing A
A seventh lens 17 having a negative power with the concave surface facing the enlargement side A, an eighth lens 18 having a positive power with the convex surface facing the enlargement side A, and a negative lens 17 having a positive surface facing the reduction side B. A ninth lens 19 having power.

The aperture 5 is composed of a sixth lens 16 and a seventh lens 1
7 are arranged.

FIG. 5 shows an imaging lens system according to a fifth embodiment of the present invention. In the imaging lens system 1, in the fourth embodiment, the second lens group 3 is configured such that the fourth lens 14 having a positive power with the convex surface facing the enlargement side A and the concave surface facing the enlargement side A. Fifth lens 15 having negative power
A sixth lens 16 having a positive power with a convex surface facing the enlargement side A, a seventh lens 17 having a negative power with a concave surface facing the enlargement side A, and a positive lens having a convex surface facing the enlargement side A. An eighth lens 18 having power and a ninth lens 19 having negative power with the convex surface facing the reduction side B, and n ₂ > n ₁ (1) n ₂ > n ₃ (2) 1 .8f <OAL <2.1f (3) 0.058 <TT / (OAL · f) <0.065 (4) Each condition (1), (2), (3), (4) The configuration is satisfied, and the other configuration is the same as that of the fourth embodiment.

FIG. 6 shows an imaging lens system according to a sixth embodiment of the present invention. In the imaging lens system 1, in the fourth embodiment, the second lens group 3 is configured such that the fourth lens 14 having a negative power whose convex surface is directed to the enlargement side A and the convex surface is directed to the enlargement side A. Fifth lens 15 having positive power
A sixth lens 16 having a positive power with a convex surface facing the enlargement side A, a seventh lens 17 having a negative power with a concave surface facing the enlargement side A, and a positive lens having a convex surface facing the enlargement side A. An eighth lens 18 having power and a ninth lens 19 having negative power with the convex surface facing the reduction side B, and n ₂ > n ₁ (1) n ₂ > n ₃ (2) 1 .8f <OAL <3.8f (3) Each condition (1), (2), (3), (4) of 0.041 <TT / (OAL · f) <0.065 (4) The configuration is satisfied, and the other configuration is the same as that of the fourth embodiment.

FIG. 7 shows a recording optical device according to an embodiment of the present invention. The recording optical device 100 includes a semiconductor laser array 101 in which nxm laser light sources are arranged in an array, and a laser beam from each laser light source can be emitted in parallel and independently at the same time. After converging a plurality of laser beams emitted in parallel from the light source to the combined focal position 5a, the photosensitive drum 102 is enlarged at a predetermined angle of view and rotated by a driving device (not shown).
An imaging lens system 1 for forming an image thereon, an image memory 103 storing an image signal, an image signal read out from the image memory 103, and a signal processing for processing the image signal and outputting a recording signal corresponding to a recording pattern. A laser driving circuit 105 for inputting a recording signal from the signal processing circuit 104 to drive the semiconductor laser array 101; and outputting a control signal to the laser driving circuit 105 to output the laser driving circuit 10
5 for performing the driving of the control circuit 5.
The recording optical device 100 is not shown, but
Image forming means such as a charging device, a developing device, and a transfer device are provided around the photoreceptor drum 102, and a paper supply unit for supplying recording paper to the transfer device is provided at a stage preceding the transfer device, and a sheet feeding unit is provided at a stage subsequent to the transfer device. And a fixing unit for fixing the toner image transferred to the recording paper, a paper discharge unit for discharging the recording paper on which the toner image is fixed, and the like. According to this configuration, the total optical path length is shortened, the size can be reduced, and the aperture ratio increases with a large screen size. Also,
Since the semiconductor laser array 101 can be used as the light source on the reduction side, high resolution can be obtained. Although FIG. 1 shows the first embodiment of the imaging lens system 1, the imaging lens system 1 may have the second to sixth embodiments.

[0034]

First, first to sixth examples corresponding to the first embodiment will be described. (First Embodiment) Table 1 shows lens data of the imaging lens system 1 of the first embodiment.

[Table 1]

In Table 1, ri indicates the radius of curvature of the lens, and di indicates the distance between adjacent surfaces of each lens surface and the distance between the lens surface and the diaphragm 5. Also, nj is d
In the line, the refractive index of each lens, and υ indicates the dispersion value (Abbe number) of each lens.

Imaging lens system 1 having the above lens data
Effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance (total optical path length) TT, and total lens length O
AL is set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 658.3202 mm, OAL = 2
20mm

FIGS. 8 (a), (b), (c) and FIG. 9 show the spherical aberration, astigmatism, distortion and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. Are respectively shown. Each of the figures is for 780 nm, which is the wavelength of the semiconductor laser used as the light source on the reduction side B. 8 (b) and 9, s represents a sagittal image plane, and m represents a meridional image plane.
In the embodiments described later, the same reference numerals are used and the description is omitted.

(Second Embodiment) Table 2 shows lens data of the imaging lens system 1 of the second embodiment.

[Table 2]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 657.844 mm, OAL = 2
20mm

FIGS. 10 (a), (b), (c) and FIG.
The spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above are shown. In the present embodiment, the distortion is kept within 0.1% while keeping the entire lens length the same as in the first embodiment.

(Third Embodiment) Table 3 shows lens data of the imaging lens system 1 of the third embodiment.

[Table 3]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 632.3137 mm, OAL = 1
80mm

FIGS. 12 (a), 12 (b) and 12 (c) and FIG.
The spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above are shown. In this embodiment, the entire length of the lens is set to 180 mm, which is shorter than that of the first embodiment.

(Fourth Embodiment) Table 4 shows lens data of the imaging lens system 1 of the fourth embodiment.

[Table 4]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 630.4017 mm, OAL = 1
80mm

FIGS. 14 (a), (b) and (c) and FIG.
The spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above are shown. In the present embodiment, the distortion is kept within 0.1% while keeping the entire length of the lens the same as in the third embodiment.

(Fifth Embodiment) Table 5 shows lens data of the imaging lens system 1 of the fifth embodiment.

[Table 5]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 660.281 mm, OAL = 1
50mm

FIGS. 16 (a), (b) and (c) and FIG.
The spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above are shown. In this embodiment, the entire length of the lens is set to 150 mm, which is shorter than that of the first embodiment.

(Sixth Embodiment) Table 6 shows lens data of the imaging lens system 1 of the sixth embodiment.

[Table 6]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 599.1976mm, OAL = 1
50mm

FIGS. 18 (a), (b), (c) and FIG.
The spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above are shown. In the present embodiment, the distortion is set to be within 0.1% while keeping the entire lens length the same as in the fifth embodiment.

Next, the seventh to seventh embodiments corresponding to the second embodiment will be described.
A tenth embodiment will be described. (Seventh Embodiment) Table 7 shows lens data of the imaging lens system 1 of the seventh embodiment.

[Table 7]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 672.7701 mm, OAL = 2
20mm

FIGS. 20 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In each figure, reduction side B
780n which is the wavelength of the semiconductor laser used as the light source
m.

(Eighth Embodiment) Table 8 shows lens data of the imaging lens system 1 of the eighth embodiment.

[Table 8]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70mm, M
= 0.167, θ = 20 °, F = 2.5, TT = 6
65.2978 mm, OAL = 220 mm

FIGS. 22 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In the present embodiment, the distortion is set to within 0.1% while keeping the entire lens length the same as that of the seventh embodiment.

(Ninth Embodiment) Table 9 shows lens data of the imaging lens system 1 of the ninth embodiment.

[Table 9]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 639.3356 mm, OAL = 1
80mm

FIGS. 24 (a), (b) and (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In this embodiment, the entire length of the lens is set to 180 mm, which is shorter than that of the seventh embodiment.

(Tenth Embodiment) Table 10 shows lens data of the imaging lens system 1 of the tenth embodiment.

[Table 10]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 636.387 mm, OAL = 1
80mm

FIGS. 26 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In the present embodiment, the distortion is set to be within 0.1% while keeping the entire lens length the same as in the ninth embodiment.

Next, an eleventh embodiment corresponding to the third embodiment will be described.
A sixteenth embodiment will be described. (Eleventh Embodiment) Table 11 shows lens data of the imaging lens system 1 of the eleventh embodiment.

[Table 11]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 577.8939 mm, OAL = 1
50mm

FIGS. 28 (a), (b) and (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In each figure, reduction side B
780n which is the wavelength of the semiconductor laser used as the light source
m.

(Twelfth Embodiment) Table 12 shows lens data of the imaging lens system 1 of the twelfth embodiment.

[Table 12]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 574.7500mm, OAL = 1
50mm

FIGS. 30 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In this embodiment, the total length of the lens
In this embodiment, the distortion is kept within 0.1% while keeping the same as the embodiment.

(Thirteenth Embodiment) Table 13 shows lens data of the imaging lens system 1 of the thirteenth embodiment.

[Table 13]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 600.7525 mm, OAL = 1
80mm

FIGS. 32 (a), (b) and (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In this embodiment, the total length of the lens
Is 180 mm longer than that of the embodiment.

(Fourteenth Embodiment) Table 14 shows lens data of the imaging lens system 1 of the fourteenth embodiment.

[Table 14]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 598.1329 mm, OAL = 1
80mm

FIGS. 34 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In the present embodiment, the total length of the lens
In this embodiment, the distortion is kept within 0.1% while keeping the same as the embodiment.

(Fifteenth Embodiment) Table 15 shows lens data of the imaging lens system 1 of the fifteenth embodiment.

[Table 15]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 616.7161 mm, OAL = 2
20mm

FIGS. 36 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In this embodiment, the total length of the lens
220 mm, which is longer than the embodiment of FIG.

(Sixteenth Embodiment) Table 16 shows lens data of the imaging lens system 1 of the sixteenth embodiment.

[Table 16]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 619.2455 mm, OAL = 2
20mm

FIGS. 38 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In this embodiment, the total length of the lens is
In this embodiment, the distortion is kept within 0.1% while keeping the same as the embodiment.

Next, a seventeenth embodiment corresponding to the fourth embodiment will be described.
A twenty-second embodiment will be described. (Seventeenth Embodiment) Table 17 shows lens data of the imaging lens system 1 of the seventeenth embodiment.

[Table 17]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 5788.8766 mm, OAL = 1
30

FIGS. 40 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In each figure, reduction side B
780n which is the wavelength of the semiconductor laser used as the light source
m.

(Eighteenth Embodiment) Table 18 shows lens data of the imaging lens system 1 of the eighteenth embodiment.

[Table 18]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 588.3772 mm, OAL = 1
40

FIGS. 42 (a), (b) and (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In this embodiment, the total length of the lens is 17th.
This is an embodiment that is longer than the embodiment.

(Nineteenth Embodiment) Table 19 shows lens data of the imaging lens system 1 of the nineteenth embodiment.

[Table 19]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 591.9786 mm, OAL = 1
50mm

FIGS. 44 (a), (b) and (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. This embodiment is an embodiment in which the overall length of the lens is longer than those of the seventeenth and eighteenth embodiments.

(Twentieth Embodiment) Table 20 shows lens data of the imaging lens system 1 of the twentieth embodiment.

[Table 20]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 50 mm, M = 0.167, θ = 27 °, F
= 2.5, TT = 468.7013 mm, OAL = 1
50mm

FIGS. 46 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In this embodiment, the angle of view is widened in order to shorten the total optical path length as compared with the seventeenth, eighteenth, and nineteenth embodiments. In order to obtain the same image height (screen size), the effective focal length is shortened. It was done.

(Twenty-First Embodiment) Table 21 shows lens data of the imaging lens system 1 of the twenty-first embodiment.

[Table 21]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 50 mm, M = 0.167, θ = 27 °, F
= 2.5, TT = 488.9674 mm, OAL = 1
80mm

FIGS. 48 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In this embodiment, the total length of the lens
This is an embodiment that is longer than the embodiment of FIG.

(22nd Embodiment) Table 22 shows lens data of the imaging lens system 1 of the 22nd embodiment.

[Table 22]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 50 mm, M = 0.167, θ = 27 °, F
= 2.5, TT = 510.3806 mm, OAL = 2
20mm

FIGS. 50 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In this embodiment, the total length of the lens
This is an embodiment that is longer than the twenty-first and twenty-first embodiments.

Next, a second embodiment corresponding to the fifth embodiment will be described.
Third, a twenty-fourth embodiment will be described. (Twenty-third embodiment) Table 23 shows lens data of the imaging lens system 1 of the twenty-third embodiment.

[Table 23]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 581.868mm, OAL = 1
30mm

FIGS. 52 (a), (b) and (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In each figure, reduction side B
780n which is the wavelength of the semiconductor laser used as the light source
m.

(Twenty-fourth Embodiment) Table 24 shows the lens data of the imaging lens system 1 of the twenty-fourth embodiment.

[Table 24]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 580.9683 mm, OAL = 1
40mm

FIGS. 54 (a), (b) and (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In this embodiment, the total length of the lens
This is an embodiment that is longer than the embodiment.

Next, a twenty-fifth embodiment corresponding to the sixth embodiment will be described.
A thirty-fourth embodiment will be described. (25th embodiment) Table 25 shows lens data of the imaging lens system 1 of the 25th embodiment.

[Table 25]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 583.8743 mm, OAL = 1
40mm

FIGS. 56 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In each figure, reduction side B
780n which is the wavelength of the semiconductor laser used as the light source
m.

(Twenty-Sixth Embodiment) Table 26 shows lens data of the imaging lens system 1 of the twenty-sixth embodiment.

[Table 26]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 589.495 mm, OAL = 1
50mm

FIGS. 58 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In this embodiment, the total length of the lens is 25th.
This is an embodiment that is longer than the embodiment.

(Twenty-Seventh Embodiment) Table 27 shows lens data of the imaging lens system 1 of the twenty-seventh embodiment.

[Table 27]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 595.313mm, OAL = 1
50mm

FIGS. 60 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. This embodiment is another embodiment in which the overall lens length is the same as that of the twenty-sixth embodiment.

(28th Embodiment) Table 28 shows lens data of the imaging lens system 1 of the 28th embodiment.

[Table 28]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 620.2590 mm, OAL = 1
80mm

FIGS. 62 (a), (b) and (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In this embodiment, the total length of the lens is 25th.
This is an embodiment longer than the twenty-seventh embodiment.

(29th embodiment) Table 29 shows lens data of the imaging lens system 1 of the 29th embodiment.

[Table 29]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 622.6031 mm, OAL = 1
80mm

FIGS. 64 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In the present embodiment, the total lens length is set to 28th.
This is the same as the embodiment of FIG.

(Thirtieth Embodiment) Table 30 shows lens data of the imaging lens system 1 of the thirtieth embodiment.

[Table 30]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 649.3888 mm, OAL = 2
20mm

FIGS. 66 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In this embodiment, the total length of the lens is 25th.
To the twenty-ninth embodiment.

(Thirty-First Embodiment) Table 31 shows lens data of the imaging lens system 1 of the thirty-first embodiment.

[Table 31]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 70 mm, M = 0.167, θ = 20 °, F
= 2.5, TT = 649.314 mm, OAL = 22
0mm

FIGS. 68 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In this embodiment, the total length of the lens
This is the same as the embodiment of FIG.

(32nd Embodiment) Table 32 shows the lens data of the imaging lens system 1 of the 32nd embodiment.

[Table 32]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 60 mm, M = 0.167, θ = 23 °, F
= 2.5, TT = 531.2445mm, OAL = 1
50mm

FIGS. 70 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In the present embodiment, the angle of view is widened in order to shorten the total optical path length as compared with the twenty-fifth to thirty-first embodiments, and the effective focal length is shortened in order to obtain the same image height (screen size). is there.

(Thirty-third Embodiment) Table 33 shows lens data of the imaging lens system 1 of the thirty-third embodiment.

[Table 33]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 60 mm, M = 0.167, θ = 23 °, F
= 2.5, TT = 559.0416 mm, OAL = 1
80mm

FIGS. 72 (a), (b), (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In the present embodiment, the total length of the lens
Are longer than those of the embodiment.

(Thirty-Fourth Embodiment) Table 34 shows lens data of the imaging lens system 1 of the thirty-fourth embodiment.

[Table 34]

Imaging lens system 1 having the above lens data
The effective focal length f, magnification M, half angle of view θ, effective F-number F, object-image distance TT, and overall lens length OAL are set as follows. f = 60 mm, M = 0.167, θ = 23 °, F
= 2.5, TT = 565.9905mm, OAL = 2
20mm

FIGS. 74 (a), (b) and (c) and FIG.
FIG. 3 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral aberration on the reduction side B of the imaging lens system 1 configured as described above. In the present embodiment, the total length of the lens
In addition, the length is longer than that of the thirty-third embodiment.

[0137]

As described above, according to the present invention, since the first lens group is composed of a plurality of lenses having negative power, a large screen size can be obtained. Further, since the second lens group is composed of a plurality of lenses having concave surfaces facing the stop on both sides of the stop, the aperture ratio is increased. Also,
Since the third lens group is composed of a plurality of lenses having positive power, a telecentric configuration is facilitated, and a semiconductor laser array capable of obtaining high resolution can be used as a light source. Further, since the first lens group is configured as a so-called retrofocus type, and the second and third lens groups are configured as a so-called modified double Gaussian type, the overall length of the lens is shortened and the size can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an imaging lens system according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing an imaging lens system according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing an imaging lens system according to a third embodiment of the present invention.

FIG. 4 is a sectional view showing an imaging lens system according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view showing an imaging lens system according to a fifth embodiment of the present invention.

FIG. 6 is a sectional view showing an imaging lens system according to a sixth embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of a recording optical device according to an embodiment of the present invention.

8A and 8B are graphs showing various aberrations in the first embodiment of the present invention, wherein FIG. 8A is a spherical aberration diagram, FIG. 8B is an astigmatism diagram, and FIG. 8C is a distortion aberration diagram.

FIG. 9 is a lateral aberration diagram in the first example of the present invention.

10A and 10B are graphs showing various aberrations in the second embodiment of the present invention, wherein FIG. 10A is a spherical aberration diagram, FIG. 10B is an astigmatism diagram, and FIG. 10C is a distortion aberration diagram.

FIG. 11 is a lateral aberration diagram in the second example of the present invention.

12A and 12B are graphs showing various aberrations in the third example of the present invention, wherein FIG. 12A is a spherical aberration graph, FIG. 12B is an astigmatism graph, and FIG. 12C is a distortion aberration graph.

FIG. 13 is a lateral aberration diagram in the third example of the present invention.

14A and 14B are diagrams illustrating various aberrations in the fourth example of the present invention, in which FIG. 14A is a spherical aberration diagram, FIG. 14B is an astigmatism diagram, and FIG. 14C is a distortion diagram.

FIG. 15 is a lateral aberration diagram in the fourth embodiment of the present invention.

16A and 16B are graphs showing various aberrations in the fifth embodiment of the present invention, wherein FIG. 16A is a spherical aberration diagram, FIG. 16B is an astigmatism diagram, and FIG. 16C is a distortion diagram.

FIG. 17 is a lateral aberration diagram in the fifth embodiment of the present invention.

18A and 18B are graphs showing various aberrations in the sixth embodiment of the present invention, wherein FIG. 18A is a spherical aberration graph, FIG. 18B is an astigmatism graph, and FIG. 18C is a distortion aberration graph.

FIG. 19 is a lateral aberration diagram in the sixth example of the present invention.

FIGS. 20A and 20B are diagrams illustrating various aberrations in the seventh example of the present invention, in which FIG. 20A is a spherical aberration diagram, FIG. 20B is an astigmatism diagram, and FIG. 20C is a distortion aberration diagram.

FIG. 21 is a lateral aberration diagram in the seventh embodiment of the present invention.

FIGS. 22A and 22B are diagrams illustrating various aberrations in the eighth embodiment of the present invention, wherein FIG. 22A is a diagram of spherical aberration, FIG. 22B is a diagram of astigmatism, and FIG. 22C is a diagram of distortion.

FIG. 23 is a lateral aberration diagram in the eighth embodiment of the present invention.

24A and 24B are graphs showing various aberrations in the ninth embodiment of the present invention, wherein FIG. 24A is a spherical aberration graph, FIG. 24B is an astigmatism graph, and FIG. 24C is a distortion aberration graph.

FIG. 25 is a lateral aberration diagram in the ninth embodiment of the present invention.

26A and 26B are graphs showing various aberrations in the tenth embodiment of the present invention, wherein FIG. 26A is a spherical aberration graph, FIG. 26B is an astigmatism graph, and FIG. 26C is a distortion aberration graph.

FIG. 27 is a lateral aberration diagram in the tenth embodiment of the present invention.

28A and 28B are graphs showing various aberrations in the eleventh embodiment of the present invention, wherein FIG. 28A is a spherical aberration graph, FIG. 28B is an astigmatism graph, and FIG. 28C is a distortion aberration graph.

FIG. 29 is a lateral aberration diagram in the eleventh embodiment of the present invention.

30A and 30B are graphs showing various aberrations in the twelfth embodiment of the present invention, wherein FIG. 30A is a spherical aberration graph, FIG. 30B is an astigmatism graph, and FIG.

FIG. 31 is a lateral aberration diagram in the twelfth embodiment of the present invention.

FIGS. 32A and 32B are diagrams showing various aberrations in the thirteenth embodiment of the present invention, wherein FIG. 32A is a spherical aberration diagram, FIG. 32B is an astigmatism diagram, and FIG. 32C is a distortion diagram.

FIG. 33 is a lateral aberration diagram in the thirteenth embodiment of the present invention.

34A and 34B are diagrams illustrating various aberrations in the fourteenth example of the present invention, in which FIG. 34A is a spherical aberration diagram, FIG. 34B is an astigmatism diagram, and FIG. 34C is a distortion diagram.

FIG. 35 is a lateral aberration diagram in a fourteenth embodiment of the present invention.

FIGS. 36 (a) and 36 (b) are graphs showing various aberrations in the fifteenth embodiment of the present invention, wherein FIG. 36 (a) is a spherical aberration graph, FIG. 36 (b) is an astigmatism graph, and FIG.

FIG. 37 is a lateral aberration diagram in the fifteenth embodiment of the present invention.

FIGS. 38 (a) and 38 (b) are graphs showing various aberrations in the sixteenth example of the present invention, wherein FIG. 38 (a) is a spherical aberration graph, FIG. 38 (b) is an astigmatism graph, and FIG.

FIG. 39 is a lateral aberration diagram in a sixteenth example of the present invention.

FIGS. 40A and 40B are diagrams illustrating various aberrations in the seventeenth example of the present invention, in which FIG. 40A is a diagram of spherical aberration, FIG. 40B is a diagram of astigmatism, and FIG.

FIG. 41 is a lateral aberration diagram in a seventeenth example of the present invention.

42 (a) and 42 (b) are graphs showing various aberrations in the eighteenth embodiment of the present invention, wherein FIG. 42 (a) is a spherical aberration graph, FIG. 42 (b) is an astigmatism graph, and FIG. 42 (c) is a distortion graph.

FIG. 43 is a lateral aberration diagram in the eighteenth example of the present invention.

FIGS. 44 (a) and 44 (b) are graphs showing various aberrations in the nineteenth embodiment of the present invention, wherein FIG. 44 (a) is a spherical aberration graph, FIG. 44 (b) is an astigmatism graph, and FIG.

FIG. 45 is a lateral aberration diagram in the nineteenth example of the present invention.

46A to 46C are diagrams illustrating various aberrations in the twentieth embodiment of the present invention, wherein FIG. 46A is a spherical aberration diagram, FIG. 46B is an astigmatism diagram, and FIG. 46C is a distortion diagram.

FIG. 47 is a lateral aberration diagram in the twentieth embodiment of the present invention.

FIGS. 48A and 48B are graphs showing various aberrations in the twenty-first embodiment of the present invention, wherein FIG. 48A is a spherical aberration diagram, FIG. 48B is an astigmatism diagram, and FIG.

FIG. 49 is a lateral aberration diagram in the twenty-first embodiment of the present invention.

FIGS. 50A and 50B are graphs showing various aberrations in the twenty-second embodiment of the present invention, wherein FIG. 50A is a spherical aberration diagram, FIG. 50B is an astigmatism diagram, and FIG.

FIG. 51 is a lateral aberration diagram in the twenty-second embodiment of the present invention.

FIGS. 52 (a) and 52 (b) are graphs showing various aberrations in the twenty-third embodiment of the present invention, wherein FIG. 52 (a) is a spherical aberration graph, FIG. 52 (b) is an astigmatism graph, and FIG.

FIG. 53 is a lateral aberration diagram in the twenty-third embodiment of the present invention.

54A and 54B are graphs showing various aberrations in the twenty-fourth embodiment of the present invention, wherein FIG. 54A is a spherical aberration diagram, FIG. 54B is an astigmatism diagram, and FIG. 54C is a distortion diagram.

FIG. 55 is a diagram showing the lateral aberration in the twenty-fourth embodiment of the present invention;

56A and 56B are graphs showing various aberrations in the twenty-fifth embodiment of the present invention, wherein FIG. 56A is a spherical aberration diagram, FIG. 56B is an astigmatism diagram, and FIG. 56C is a distortion diagram.

FIG. 57 is a lateral aberration diagram in a twenty-fifth embodiment of the present invention.

58A and 58B are graphs showing various aberrations in the twenty-sixth embodiment of the present invention, wherein FIG. 58A is a spherical aberration graph, FIG. 58B is an astigmatism graph, and FIG.

FIG. 59 is a lateral aberration diagram in the twenty-sixth embodiment of the present invention.

60A and 60B are graphs showing various aberrations in the twenty-seventh embodiment of the present invention, wherein FIG. 60A is a spherical aberration diagram, FIG. 60B is an astigmatism diagram, and FIG. 60C is a distortion diagram.

FIG. 61 is a lateral aberration diagram in the twenty-seventh embodiment of the present invention.

62 (a) and 62 (b) are graphs showing various aberrations in the twenty-eighth embodiment of the present invention, wherein FIG. 62 (a) is a spherical aberration graph, FIG. 62 (b) is an astigmatism graph, and FIG.

FIG. 63 is a diagram showing the lateral aberration in the twenty-eighth embodiment of the present invention;

FIGS. 64A and 64B are graphs showing various aberrations in the twenty-ninth embodiment of the present invention, wherein FIG. 64A is a spherical aberration graph, FIG. 64B is an astigmatism graph, and FIG.

FIG. 65 is a diagram showing the lateral aberration in the twenty-ninth embodiment of the present invention;

FIGS. 66 (a) and 66 (b) are graphs showing various aberrations in the thirtieth embodiment of the present invention, wherein FIG. 66 (a) is a spherical aberration graph, FIG. 66 (b) is an astigmatism graph, and FIG.

FIG. 67 is a diagram showing the lateral aberration in the thirtieth embodiment of the present invention;

FIGS. 68 (a) and 68 (b) are graphs showing various aberrations in the thirty-first embodiment of the present invention, FIG. 68 (a) is a spherical aberration graph, FIG. 68 (b) is an astigmatism graph, and FIG.

FIG. 69 is a diagram showing the lateral aberration in the thirty-first embodiment of the present invention;

FIGS. 70 (a) and 70 (b) are graphs showing various aberrations in the thirty-second embodiment of the present invention, wherein FIG. 70 (a) is a spherical aberration graph, FIG. 70 (b) is an astigmatism graph, and FIG.

FIG. 71 is a diagram showing the lateral aberration in the thirty-second embodiment of the present invention;

FIGS. 72 (a) and 72 (b) are graphs showing various aberrations in the thirty-third embodiment of the present invention, wherein FIG. 72 (a) is a spherical aberration graph, FIG. 72 (b) is an astigmatism graph, and FIG.

FIG. 73 is a diagram showing the lateral aberration in the thirty-third embodiment of the present invention;

74A and 74B are graphs showing various aberrations in the thirty-fourth embodiment of the present invention, wherein FIG. 74A is a spherical aberration diagram, FIG. 74B is an astigmatism diagram, and FIG.

FIG. 75 is a diagram showing the lateral aberration in the thirty-fourth embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Imaging lens system 2 1st lens group 3 2nd lens group 4 3rd lens group 5 Aperture 5a Synthetic focal position 11 1st lens 12 2nd lens 13 3rd lens 14 4th lens 15 5th lens 16 6th lens 17 Seventh lens 18 Eighth lens 19 Ninth lens 20 Tenth lens 21 Eleventh lens 22 Twelfth lens 100 Recording optical device 101 Semiconductor laser array 102 Photoconductor drum 103 Image memory 104 Signal processing circuit 105 Laser drive circuit 106 Control circuit s Sagittal image plane m Meridional image plane

Claims (12)

[Claims] 1. An imaging lens system which uses a predetermined number of lenses and enlarges or reduces incident light from a reduction side or an enlargement side to form an image on an image formation surface, wherein the enlargement side has a negative power. A first lens group including a plurality of lenses, a diaphragm arranged so as to coincide with a combined focal position of the predetermined number of lenses, and a diaphragm arranged on the reduction side of the first lens group, and on both sides of the diaphragm. A second lens group including a plurality of lenses having a concave surface facing the diaphragm; and a third lens group disposed on the reduction side of the second lens group and including a plurality of lenses having positive power. Imaging lens system. 2. The image forming apparatus according to claim 1, wherein the first lens group has an angle of view of 20 to 30 degrees, and the second lens group has a brightness of light formed on the image forming surface of F = 2. The third lens group is disposed on the image forming surface on the reduction side at 10
The imaging lens system according to claim 1, wherein the imaging lens system is configured to have a resolution of 0 / mm or more. 3. The first lens group includes a first lens having a negative power with a convex surface facing the enlargement side, a second lens having a positive power with a convex surface facing the enlargement side, and the enlargement side. A third lens having a negative power with a convex surface facing the side, the second lens group having a fourth lens having a negative power with the convex surface facing the magnifying side, and having a convex surface facing the magnifying side. A fifth lens having a positive power, a sixth lens having a negative power with a concave surface facing the enlargement side, and a seventh lens having a negative power with a convex surface facing the reduction side; The third lens group includes an eighth lens having a positive power with a convex surface facing the reduction side, a ninth lens having a positive power with a convex surface facing the reduction side, and a positive power having a convex surface facing the reduction side. A tenth lens having: Serial disposed between the seventh lens, the first, n ₁ the refractive index of the second and third lens, respectively, n _2, n _3, a combined focal length of the first to tenth lens f, The total length of the first to tenth lenses is O
When AL is set, n ₂ > n ₁ (1) n ₂ > n ₃ (2) 2.1f <OAL <3.2f (3) Each condition (1), (2), (3) 2. The imaging lens system according to claim 1, wherein the imaging lens system is configured to satisfy the following condition. 4. The zoom lens according to claim 1, wherein the first lens group includes a first lens having a negative power with a convex surface facing the enlargement side, a second lens having a positive power with a convex surface facing the enlargement side, and A third lens having a negative power with a convex surface facing the side, the second lens group having a fourth lens having a positive power with the convex surface facing the magnifying side, and having a convex surface facing the magnifying side. A fifth lens having a positive power, a sixth lens having a negative power with a concave surface facing the enlargement side, and a seventh lens having a negative power with a convex surface facing the reduction side; The lens group includes an eighth lens having a positive power with a convex surface facing the reduction side, a ninth lens having a positive power with a convex surface facing the reduction side, and a positive lens having a convex surface facing the reduction side. A tenth lens having a power, wherein the aperture is the It is disposed between the lens and the seventh lens, the first, n ₁ the refractive index of the second and third lens, respectively, n _2, n _3, a combined focal length of the first to tenth lens f, the total length of the first to tenth lenses is O
When AL is set, n ₂ > n ₁ (1) n ₂ > n ₃ (2) 2.5f <OAL <3.2f (3) Each condition (1), (2), (3) 2. The imaging lens system according to claim 1, wherein the imaging lens system is configured to satisfy the following condition. 5. The zoom lens according to claim 1, wherein the first lens group includes a first lens having a negative power with a convex surface facing the enlargement side, a second lens having a positive power with a convex surface facing the enlargement side, and A third lens having a negative power with a convex surface facing the negative side, wherein the second lens group has a fourth lens having a negative power with the convex surface facing the reduction side, and a convex surface facing the enlargement side. A fifth lens having a positive power, a sixth lens having a negative power with a concave surface facing the reduction side, a seventh lens having a negative power with a convex surface facing the reduction side, and a An eighth lens having a negative power with a concave surface facing the lens, wherein the third lens group has a ninth lens having a positive power with a convex surface facing the reduction side, and a positive lens with a convex surface facing the reduction side. Including a tenth lens having power The stop is disposed between the sixth lens and the seventh lens, and the first, second, and third lenses have refractive indices of n ₁ , n ₂ , and n ₃ , respectively, and the first to tenth lenses. Is the composite focal length of the lens of f, and the total length of the first to tenth lenses is O
When AL is set, n ₂ > n ₁ (1) n ₂ > n ₃ (2) 2.1f <OAL <3.2f (3) Each condition (1), (2), (3) 2. The imaging lens system according to claim 1, wherein the imaging lens system is configured to satisfy the following condition. 6. The first lens group includes a first lens having a negative power with a concave surface facing the reduction side, a second lens having a positive power with a convex surface facing the enlargement side, and the reduction lens. A third lens having a negative power with a concave surface facing the side, the second lens group having a fourth lens having a negative power with the concave surface facing the reduction side, and having a concave surface facing the reduction side. A fifth lens having a negative power, a sixth lens having a positive power with a convex surface facing the enlargement side, a seventh lens having a negative power with a concave surface facing the reduction side, and a An eighth lens having a positive power and a convex surface,
The third lens group includes a ninth lens having a negative power with a concave surface facing the enlargement side, the third lens group having a tenth lens having a positive power with a convex surface facing the reduction side, and having a convex surface on the reduction side. An eleventh lens having a positive power directed toward the zoom lens and a twelfth lens having a positive power with the convex surface directed toward the magnifying side, wherein the diaphragm is disposed between the eighth lens and the ninth lens; The refractive indices of the first, second and third lenses are respectively n ₁ , n ₂ and n ₃ , the combined focal length of the first to twelfth lenses is f, and the total length of the first to twelfth lenses O
When AL is set, n ₂ > n ₁ (1) n ₂ > n ₃ (2) 1.8f <OAL <3.8f (3) Each condition (1), (2), (3) 2. The imaging lens system according to claim 1, wherein the imaging lens system is configured to satisfy the following condition. 7. The first lens group includes a first lens having a negative power with a concave surface facing the reduction side, a second lens having a positive power with a convex surface facing the enlargement side, and the reduction lens. A third lens having a negative power with a concave surface facing the side, the second lens group having a fourth lens having a positive power with a convex surface facing the enlargement side, and a concave lens facing the reduction side. A fifth lens having a negative power, a sixth lens having a positive power with a convex surface facing the enlargement side, a seventh lens having a negative power with a concave surface facing the reduction side, and a An eighth lens having a positive power and a convex surface,
The third lens group includes a ninth lens having a negative power with a concave surface facing the enlargement side, the third lens group having a tenth lens having a positive power with a convex surface facing the reduction side, and a convex surface having a convex surface on the reduction side. An eleventh lens having a positive power directed toward the zoom lens and a twelfth lens having a positive power with the convex surface directed toward the magnifying side, wherein the diaphragm is disposed between the eighth lens and the ninth lens; The refractive indices of the first, second and third lenses are respectively n ₁ , n ₂ and n ₃ , the combined focal length of the first to twelfth lenses is f, and the total length of the first to twelfth lenses O
When the _{AL, n 2> n 1 ...} (1) n 2> n 3 ... (2) 1.8f <OAL <2.1f ... each condition (3) (1), (2), (3) 2. The imaging lens system according to claim 1, wherein the imaging lens system is configured to satisfy the following condition. 8. The first lens group includes a first lens having a negative power with a concave surface facing the reduction side, a second lens having a positive power with a convex surface facing the enlargement side, and the reduction lens. A third lens having a negative power with a concave surface facing the negative side, the second lens group having a fourth lens having a negative power with the concave surface facing the reduction side, and having a convex surface facing the enlargement side. A fifth lens having a positive power, a sixth lens having a positive power with a convex surface facing the enlargement side, a seventh lens having a negative power with a concave surface facing the reduction side, and a An eighth lens having a positive power and a convex surface,
The third lens group includes a ninth lens having a negative power with a concave surface facing the enlargement side, the third lens group having a tenth lens having a positive power with a convex surface facing the reduction side, and a convex surface having a convex surface on the reduction side. An eleventh lens having a positive power directed toward the zoom lens and a twelfth lens having a positive power with the convex surface directed toward the magnifying side, wherein the diaphragm is disposed between the eighth lens and the ninth lens; The refractive indices of the first, second and third lenses are respectively n ₁ , n ₂ and n ₃ , the combined focal length of the first to twelfth lenses is f, and the total length of the first to twelfth lenses O
When AL is set, n ₂ > n ₁ (1) n ₂ > n ₃ (2) 1.8f <OAL <3.8f (3) Each condition (1), (2), (3) 2. The imaging lens system according to claim 1, wherein the imaging lens system is configured to satisfy the following condition. 9. The imaging lens system according to claim 1, wherein said third lens group is telecentric. 10. A semiconductor laser array having a plurality of independently controllable light emitting units, and a plurality of light emitting units of the semiconductor laser array arranged on a reduction side or an enlargement side using a predetermined number of lenses. An imaging lens system for enlarging or reducing incident light to form an image on an imaging surface, wherein the imaging lens system includes a first lens group including a plurality of lenses having negative power on the enlargement side; An aperture disposed so as to coincide with the combined focal position of the predetermined number of lenses; and a plurality of lenses disposed on the reduction side of the first lens group and having concave surfaces facing the aperture on both sides of the aperture. A recording optical device comprising: a second lens group; and a third lens group disposed on the reduction side of the second lens group and including a plurality of lenses having positive power. 11. The first lens group has an angle of view of 20 to 30.
The second lens group is configured such that the brightness of light formed on the image plane is F = 2 to 3, and the third lens group is 10 on the image plane
The recording optical device according to claim 10, wherein the recording optical device is configured to have a resolution of 0 lines / mm or more. 12. The recording optical device according to claim 10, wherein said image forming surface is a surface of an image carrier on which an electrostatic latent image is formed.