JPH09236767A - Scanning optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact scanning optical system at low cost capable of performing high-speed scanning without a curvature even when a surface to be scanned is flat and performing power variation by the simple constitution. SOLUTION: This optical system is provided with a lens group Gr2 on the object side converging a light beam from a filmy screen 1, a mirror M performing main scanning for picking up the image of the filmy screen 1 by deflecting a light beam transmitted through the lens group Gr2 on the object side and a lens group Gr1 on the image side forming the images of an on-axis light beam, off-axis light beam in the sub-scanning direction (z-axis direction), deflected by the mirror M, together on the image pickup surface of a line CCD 3. A zooming optical system is used for the lens group Gr1 on the image side, the speed/range of main scanning are made to be variable by the rotation control of the mirror M and the exit pupil of the lens group Gr2 on the object side is made almost coincident with the entrance pupil of the lens group Gr1 on the image side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning optical system, for example, a scanning optical system used in a film scanner or the like capable of capturing an image at high speed.

[0002]

2. Description of the Related Art Conventionally, various film scanners have been proposed. Among them, a mirror scan type film scanner is generally well known. Mirror scan type film scanners are mainly line sensors (for example, line C) in which light receiving elements are arranged in the sub-scanning direction.
CD), a scanning optical system for forming an image of a film on a line sensor, and a mirror that swings and rotates for main scanning.

In the above film scanner, since the film screen, which is the surface to be scanned, is flat, the optical path length between the mirror and the surface to be scanned changes as the mirror rotates when scanning the film screen. There is a problem that it will end up. In order to solve such a problem, in Japanese Patent Publication No. Sho 62-20526, the above-mentioned optical path length is provided by providing a rotationally asymmetric imaging optical system in which Petzval sum or the like is defined between the mirror and the plane to be scanned. Has been proposed so that a flat surface to be scanned can be scanned at high speed without bending.

[0004]

[Problems to be Solved by the Invention] However, JP-B-62-205
The rotationally asymmetric image forming optical system used in the scanning device of No. 26 is an expensive optical system having a surface shape that is difficult to manufacture, so that there is a problem that the cost of the scanning device increases. Also, because the size of the mirror is inevitable,
It is difficult to rotate the mirror at high speed, and the film 1
There is a problem that it takes 10 seconds to several minutes to capture the frame image. Further, according to the conventional film scanner, when enlarging / reducing a film image, there is a problem that the image once captured by the line sensor must be processed. The size of the image formed on the line sensor can be changed by changing the conjugate length, but there is a problem that the entire scanning device becomes large.

The present invention has been made in view of these points, and an object thereof is to enable high-speed scanning without curvature even when the surface to be scanned is flat, and to perform zooming with a simple structure. (EN) Provided is a low-cost and compact scanning optical system capable of performing.

[0006]

In order to achieve the above object, the scanning optical system according to the first aspect of the present invention comprises an object side lens group for condensing light from an object and a light passing through the object side lens group. A mirror that performs main scanning for imaging an object by deflecting it, and an image-side lens group that forms both on-axis light and off-axis light in the sub-scanning direction deflected by the mirror on the imaging surface. In the scanning optical system, a zoom optical system is used for a lens group of the object side lens group and the image side lens group whose optical path does not change in the main scanning, and an exit pupil of the object side lens group. It is characterized in that the entrance pupil of the image-side lens group is substantially matched.

According to the structure of the first invention, both the on-axis light and the off-axis light in the sub-scanning direction are imaged on the image pickup surface, and the zoom optical system used is changed by the zooming operation. Since an image enlarged or reduced in the sub-scanning direction is formed on the image pickup surface, it is possible to perform magnification change (that is, anisotropic magnification) only in the sub-scanning direction. Further, since the zooming is performed by the zoom optical system, the conjugate length does not change during zooming. Moreover, since the zoom optical system is used as a lens group of the object-side lens group and the image-side lens group whose optical path does not change in main scanning, the light flux is not limited in main scanning. Further, since it is not necessary to process the image once formed on the image pickup surface later, it is possible to easily obtain an enlarged image / reduced image in the sub-scanning direction.

The scanning optical system according to the second aspect of the invention comprises an object side lens group that collects light from an object, and a main scan for imaging the object by deflecting the light that has passed through the object side lens group. A scanning optical system comprising: a mirror for performing an image; and an image-side lens group for forming both on-axis light and off-axis light in the sub-scanning direction, which are deflected by the mirror, on an imaging surface, the mirror rotating. The speed and the range of the main scanning are made variable by the control, and the exit pupil of the object side lens group and the entrance pupil of the image side lens group are made substantially coincident with each other.

According to the structure of the second aspect of the invention, since the speed and range of the main scanning by the mirror are variable, by setting a desired main scanning speed, the scaling in only the main scanning direction (that is, different magnification) is performed. One-sided magnification can be performed. Moreover, since the speed of main scanning is constant, distortion in the main scanning direction does not occur in the obtained image. For example, when the light passing through the object side lens group is deflected by the rotation of the mirror, the main scanning speed and range can be changed by changing the rotation angular velocity and the rotation range of the mirror. Therefore, it is possible to change the magnification only in the main scanning direction only by controlling the speed of the main scanning by controlling the rotation of the mirror. Also,
Since it is not necessary to process the image once formed on the image pickup surface later, it is possible to easily obtain an enlarged image / reduced image in the main scanning direction.

A scanning optical system according to a third aspect of the present invention comprises an object side lens group that collects light from an object and a main scan for imaging the object by deflecting the light that has passed through the object side lens group. A scanning optical system comprising: a mirror for performing an image; and an image side lens group for forming both on-axis light and off-axis light in the sub-scanning direction deflected by the mirror on an imaging surface, the object-side lens Group, the image side lens group, a zoom optical system is used for a lens group whose optical path does not change in the main scanning, the main scanning speed and range are made variable by rotation control of the mirror, and the object side lens group And the entrance pupil of the image-side lens unit are substantially aligned with each other.

A third aspect of the invention is a combination of the first and second aspects of the invention. Therefore, by simultaneously performing the magnification change in the sub-scanning direction using the zoom optical system and the magnification change in the main-scanning direction by the main-scanning speed control,
It is possible to change the magnification in both directions of the sub-scan, and it is also possible to simultaneously realize an isotropic / anisotropic magnification and a high zoom ratio.

In the first to third inventions, the expression "the exit pupil of the object side lens group and the entrance pupil of the image side lens group are substantially matched" means that the exit side of the object side lens group having substantially the same pupil diameter. It means that the pupil and the entrance pupil of the image side lens group are located at substantially the same position. According to the above definition, in an optical system in which the optical axes of the object-side lens group and the image-side lens group are coincident with each other, regarding the configuration in which the exit pupil of the object-side lens group and the entrance pupil of the image-side lens group coincide with each other, (1 ) If the two pupils have substantially the same pupil diameter but are not located at substantially the same position, (2)
If the two pupils are located at substantially the same position but do not have substantially the same pupil diameter, (3) if the two pupils have different pupil diameters and different positions, (4) First to third
The invention will be described in more detail in the order of.

In the case of the configuration (1), since the positions of the two pupils on the optical axis are not substantially the same position, for example, when the axial light is emitted as divergent light from the object side lens group, A part of the upper light cannot pass through the entrance pupil of the image side lens group, resulting in a loss of light quantity. On the other hand, in the case where axial light is emitted as convergent light from the object side lens group, the image side lens group has a large area in which light does not pass, and the entire optical system becomes large. If the exit pupil of the object-side lens group and the entrance pupil of the image-side lens group are not at substantially the same position, all off-axis light (that is, light having an image height) that has passed through the exit pupil of the object-side lens group It cannot enter the entrance pupil of the image side lens group.

In the case of the configuration of (2), since the exit pupil of the object side lens group and the entrance pupil of the image side lens group are located at substantially the same position, the pupil having the smaller pupil diameter is substantially the same. Will have the effect of regulating the. Therefore, when the exit pupil diameter of the object side lens group is larger than the entrance pupil diameter of the image side lens group,
Not all light on the object side can be transmitted to the image side regardless of on-axis light and off-axis light. On the contrary, when the entrance pupil diameter of the image side lens group is larger than the exit pupil diameter of the object side lens group, the image side lens group has a large area in which light does not pass, and the entire optical system is It becomes large.

In the case of the configuration (3), the exit pupil diameter of the object side lens group and the entrance pupil diameter of the image side lens group are appropriately set so that axial light is transmitted from the object side lens group to the image side lens group without omission. Can be specified. However, even in this case, if the exit pupil of the object side lens group and the entrance pupil of the image side lens group are not at substantially the same position, as in the case of (1), the exit pupil of the object side lens group is passed. Not all off-axis light can enter the entrance pupil of the image side lens group.

On the other hand, in the first to third inventions of (4), the exit pupil of the object side lens group and the entrance pupil of the image side lens group are made to substantially coincide with each other. Not only light but also off-axis light can be transmitted from the object side lens group to the image side lens group without fail.

For example, in a laser scanning optical system used in a printer or the like, on-axis light and off-axis light are both used in the main scanning direction, so that the position near the entrance pupil position of the lens group located on the image side. A mirror is placed. However, since off-axis light in the sub-scanning direction is not used (that is, no image height is provided in the sub-scanning direction), each of the object-side lens group and the image-side lens group in the first to third inventions It is not necessary to match the pupils of the lens groups. On the other hand, in the first to third inventions, both the on-axis light and the off-axis light in the sub-scanning direction deflected by the mirror are imaged on the imaging surface by the image side lens group (that is, the sub-scanning direction). The image passing through the exit pupil of the object side lens group must be substantially matched with the exit pupil of the object side lens group and the entrance pupil of the image side lens group as described above. It is impossible to make all the external light enter the entrance pupil of the image side lens group.

When the exit pupil of the object side lens group and the entrance pupil of the image side lens group are made to substantially coincide with each other as described above, the object side lens group and the image side lens group become one lens system sharing a pupil. . When an ordinary optical system is used, an object is scanned while drawing an arc when the mirror is rotated, so that the image plane is curved. However, when the exit pupil of the object-side lens group and the entrance pupil of the image-side lens group are made to substantially coincide with each other as described above, field curvature does not occur in each of the object-side lens group and the image-side lens group. The curvature of the image plane does not occur in the entire scanning optical system. Since it is easy to correct the field curvature for each of the object-side lens group and the image-side lens group, it is not necessary to use an optical system having a complicated surface shape. For example, only a rotationally symmetric spherical system can be used. An object side lens group and an image side lens group can be configured. This rotationally symmetric spherical system is inexpensive and easy to manufacture.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A scanning optical system embodying the present invention will be described below with reference to the drawings. In each figure, x
The axis, the y-axis, and the z-axis indicate axes orthogonal to each other. First, FIG. 1 shows a basic configuration of a scanning optical system embodying the present invention. This scanning optical system mainly includes, in order from the image side, the image side lens group Gr1, the mirror M, and the object side lens group Gr.
It is a mirror scanning type scanning optical system composed of two. A film screen 1 is arranged at a fixed position on the object side of the scanning optical system during image pickup, and a line CCD 3 and a filter 2 are arranged on the image side of the scanning optical system. Instead of the filter 2, a three-plate type color separation prism for color separation may be used.

The object side lens group Gr2 (the optical axis of which is parallel to the x axis) collects the light from the film screen 1. In FIG. 1, RB is the axial light in the main / sub scanning direction, RA is the object height Z (+) in the sub scanning direction,
The image height Z '(-) is off-axis light, and RC is the object height Z (-) and image height Z' (+) off-axis light in the sub-scanning direction. The planar mirror M performs main scanning of the film screen 1 by deflecting the light that has passed through the object side lens group Gr2. The deflection is performed by rotating the mirror M, and the main scanning of the film screen 1 is performed in the y-axis direction. Image side lens group Gr1
(In this portion, the optical axis is parallel to the y-axis.) Indicates that both the on-axis light and the off-axis light in the sub-scanning direction (z-axis direction) deflected by the mirror M are on the imaging surface of the line CCD 3. Form an image. The image formed on the image pickup surface of the line CCD 3 is a line-shaped image in the sub-scanning direction (z-axis direction) on the film screen 1, and is captured by the line CCD 3 line by line as image information.

The lenses constituting the object side lens group Gr2 have a circular yz cross section so as to cover the luminous flux in both the y-axis and z-axis directions. In contrast,
The image-side lens group Gr1 needs to cover the light beam only in the sub-scanning direction (z-axis direction), which is the light-receiving element arrangement direction of the line CCD 3. The side surface in the direction is cut). By thus forming the image-side lens group Gr1 in an oval shape, it is possible to save space in the scanning device.

In this scanning optical system, the line CCD 3 is used as the image pickup section, but another line sensor may be used as the image pickup section instead of the line CCD 3, and a photosensitive drum is used as the image pickup section. Good. When the photoconductor drum is used, the generatrix thereof is arranged so as to be parallel to the sub-scanning direction, and the rotation of the photoconductor drum is controlled by the mirror
Synchronize with the rotation of.

Further, although this scanning optical system is applied to a film scanner, the scanning optical system of the present invention can be applied to other scanning devices. For example, instead of the line CCD 3, a device (for example, an LED array or a transmissive LCD panel) that emits light including image information is arranged, and instead of the film screen 1, the light including image information is received and read, Light receiving device for recording (Area C
A CD or a planar photoconductor) may be provided. In this case, the image side lens group Gr1 becomes the object side lens group, and the object side lens group Gr2 becomes the image side lens group.

<< Optical Configuration Common to First and Second Embodiments >> FIG. 2 is an x, y-z sectional view (that is, a state in which the first embodiment is developed in the x and y axis directions). , A sub-scan sectional view). In FIG. 2, [T] is a high magnification state (telephoto end),
[W] indicates the development optical paths in the x and y axis directions in the low magnification state (wide-angle end). 3 to 5 are xy sectional views (that is, main scanning sectional views) of the second embodiment. 3 shows the mirror rotation angle (that is, the mirror swing angle) θ =
The optical path at 45 ° (at this time, the object height Y = 0) is shown, FIG. 4 shows the optical path at the mirror rotation angle θ = 48.5 °, and FIG. 5 shows the mirror rotation angle θ = 41.5. Shows the optical path in °. 2 and 3, Si (i = 1, 2, 3, ...) Shows the i-th surface counted from the object (film screen 1) side.

In the first and second embodiments, the image side lens group Gr1 is composed of nine rotationally symmetric spherical lenses,
The object side lens group Gr2 is composed of six rotationally symmetric spherical lenses. A mirror M is provided on the image side of the object side lens group Gr2, and the mirror M and the image side lens group Gr are provided.
1 is provided with a diaphragm A, and the image side lens group Gr1
A filter 2 is provided on the image side (on the side of the line CCD 3). In the first and second embodiments, the parallel light is incident on the mirror M, but the convergent light or the divergent light may be incident.

The lenses constituting the object side lens group Gr2 have a circular yz cross section so as to cover the luminous flux in both the y-axis and z-axis directions. The same applies to the lenses forming the image-side lens group Gr1, and x
X to cover the light flux in both the z-axis and z-axis directions.
-The z section has a circular shape. However, since the image-side lens group Gr1 needs to cover the light flux only in the sub-scanning direction (z-axis direction), which is the light-receiving element arrangement direction of the line CCD 3, the xz section is long in the z-axis direction as described above. The oval shape is desirable in order to save space in the scanning device.

In the first and second embodiments, the exit pupil of the object side lens group Gr2 and the entrance pupil of the image side lens group Gr1 are substantially aligned. Therefore, all the on-axis light and off-axis light that have passed through the exit pupil of the object-side lens group Gr2 enter the entrance pupil of the image-side lens group Gr1, and from the object-side lens group Gr2 to the image-side lens group Gr1. It is transmitted without exception. Therefore, both the on-axis light and the off-axis light in the sub-scanning direction deflected by the mirror M are imaged on the image pickup surface of the line CCD 3 by the image side lens group Gr1.

As described above, when the exit pupil of the object side lens group Gr2 and the entrance pupil of the image side lens group Gr1 are made to substantially coincide with each other,
The object side lens group Gr2 and the image side lens group Gr1 form one lens system that shares the pupil. The object-side lens group Gr2 and the image-side lens group Gr1 are composed of only rotationally symmetric spherical systems as described above, and the field curvatures thereof are well corrected. Therefore, the curvature of the image plane does not occur in the entire scanning optical system. As described above, the object-side lens group Gr2 and the image-side lens group Gr2 are formed by a rotationally symmetric spherical system that is inexpensive and easy to manufacture.
By configuring No. 1, the cost reduction of the scanning device can be achieved. Further, since the scanning optical system has a simple spherical system, it is easy to cope with the increase in the rotation speed of the mirror M, and as a result, the image capture of one frame of 135 film is 0.2 to 1. It can be done in about a second.

When the main scanning of the film screen 1 is performed by deflecting light by the mirror M, if the mirror M acts as a diaphragm for regulating the light flux, the projection changes with the change in the angle formed by the mirror M and the light flux. To do. The amount of light incident on the image-side lens group Gr1 changes due to the influence of this change in projection. For example, as the mirror rotation angle θ increases, the amount of light received by the mirror M increases, and conversely, as the mirror rotation angle θ decreases, the amount of light received by the mirror M decreases.
Therefore, light amount unevenness occurs in the image captured by the line CCD 3.

According to the configurations of the first and second embodiments,
Since the diaphragm A is disposed between the image-side lens group Gr1 and the mirror M, the light flux reflected without being restricted by the mirror M is restricted by the diaphragm A. As a result, the amount of light incident on the image side lens group Gr1 becomes constant, and deterioration of the illuminance distribution (that is, the illuminance distribution on the imaging surface of the line CCD 3) is prevented. If the diaphragm A is arranged between the object side lens group Gr2 and the mirror M, vignetting will occur in the light beam in the main scanning.

When the main scanning of the film screen 1 is performed by the mirror M, the optical path in the object side lens group Gr2 changes. That is, in the main scanning direction, even if the light that enters the object-side lens group Gr2 is off-axis light, it will enter the image-side lens group Gr1 as axial light. However, since the object-side lens group Gr2 and the image-side lens group Gr1 have the image forming performance as independent front diaphragm lenses with the diaphragm A as the front diaphragm, they are sufficiently combined as a whole scanning optical system. Image performance is obtained.

The image-side lens group Gr1 is an optical system that is substantially telecentric on the image side, and is therefore of a multi-plate type (for example,
It is suitable when a line sensor such as a (three-plate type) line CCD is used as an imaging unit. This is because the more telecentric the image side lens group Gr1 is on the image side, the better the matching of the angular characteristics of the dichroic film of the multicolor separation prism (for example, the three color separation prism). Further, when the incident light to the object side lens group Gr2 has an angle with respect to the optical axis, the illuminance distribution deteriorates according to the cosine fourth law, but the object side lens group Gr2 is substantially telecentric to the object side. Since it is an optical system, it is advantageous in preventing the deterioration of the illuminance distribution.

<< First Embodiment (FIG. 2) >> A feature of the first embodiment is that a zoom optical system is used as the image side lens group Gr1 whose optical path does not change in the main scanning.
In the first embodiment, a zoom optical system including three zoom groups GrA, GrB, GrC is used as the image side lens group Gr1, and the zoom groups GrA, GrB, GrC are used.
Magnification is carried out by moving in the optical axis AX direction. Note that arrows mA, mB, and mC in FIG. 2 indicate the loci of zoom movement of the zoom groups GrA, GrB, and GrC from the high-magnification state [T] to the low-magnification state [W].

According to the configuration of this scanning optical system, the line C
Both the on-axis light and the off-axis light in the sub-scanning direction are imaged on the image pickup surface of the CD 3, and the zoom optical system used as the image side lens group Gr1 is moved in the sub-scanning direction by the zooming operation. Since an enlarged or reduced image is formed on the image pickup surface of the line CCD 3, it is possible to perform magnification change (that is, anisotropic magnification) only in the sub-scanning direction (z-axis direction). Also,
Since the zooming is performed by the zoom optical system, the conjugate length does not change during zooming. Therefore, by using this scanning optical system, the scanning device can be effectively downsized.
Moreover, since the optical path of the image side lens group Gr1 which is the zoom optical system does not change in the main scanning, the light flux is not limited in the main scanning.

Further, since it is not necessary to process the image once formed on the image pickup surface of the line CCD 3 (that is, the captured image), an enlarged image / reduced image in the sub-scanning direction can be easily obtained. You can Therefore, it is possible to improve convenience and flexibly deal with the captured image. Further, since the zoom optical system composed of a rotationally symmetric spherical system which is inexpensive and easy to manufacture is only used as the image side lens group Gr1, this scanning optical system effectively reduces the cost of the scanning device. be able to.

<< Second Embodiment (FIGS. 3 to 5) >> A feature of the second embodiment is that the speed of main scanning by the mirror M is constant and variable. By rotating the mirror M in the main scanning range of θ = 41.5 ° to 48.5 °, the main scanning of the film screen 1 in the high magnification state [T] is performed,
The magnification is changed by changing the speed of the main scanning.

In the configuration of this scanning optical system, since the speed and range of the main scanning by the mirror M are variable, only the main scanning direction (y-axis direction) can be set by setting a desired main scanning speed and main scanning range. Can be varied (that is, anisotropic magnification). For example, if the main scanning speed is set low, an enlarged image can be captured, and conversely, if the main scanning speed is set high, a reduced image can be captured.

Since the main scanning speed can be changed by changing the rotation angular velocity of the mirror M, the main scanning speed can be set by setting the rotation angular velocity of the mirror M. Further, the main scanning range can be set by setting the rotation range of the mirror M. Therefore, the main scanning speed and the main scanning range can be controlled only by controlling the rotation of the mirror M. Further, since the controlled main scanning speed is constant, distortion in the main scanning direction does not occur in the obtained image. This is because if the main scanning speed is kept constant by controlling the rotational angular velocity of the mirror M, distortion in the main scanning direction will not occur.

Further, since it is not necessary to process the image (that is, the captured image) once formed on the image pickup surface of the line CCD 3, it is possible to easily obtain an enlarged image / reduced image in the main scanning direction. You can Therefore, it is possible to improve convenience and flexibly deal with the captured image. Each of the lens groups Gr1 and Gr2 is composed of an inexpensive and easy-to-manufacture rotationally symmetric spherical system, and has a simple configuration in which the magnification change in the main scanning direction is performed only by controlling the rotation of the mirror. The cost of the device can be effectively reduced.

<< Combination of First and Second Embodiments
(FIGS. 2 to 5) >> The variable power configurations of the first and second embodiments may be combined to perform the variable power operations at the same time. If the scaling in the sub-scanning direction using the zoom optical system in the first embodiment and the scaling in the main-scanning direction by the main-scanning speed control in the second embodiment are performed at the same time, the main scanning / sub-scanning is performed. It is possible to perform zooming in both directions of scanning, and it is possible to simultaneously achieve isotropic / anisotropic magnification and high zoom ratio.

[0041]

EXAMPLES The configuration of the scanning optical system embodying the present invention will be described more specifically below with reference to construction data and the like. The examples given here are examples corresponding to the first and second embodiments (FIGS. 1 to 5) described above. Then, in the construction data of this example, Si (i = 1,2,3, ...) is the i-th surface counted from the object side, and ri (i = 1,2,3, ...) is The radius of curvature of the i-th surface Si counted from the object side, di (i = 1,2,3, ...) indicates the i-th axial upper surface distance counted from the object side, and Ni (i = 1 , 2, 3, ...) Shows the refractive index (Nd) of the i-th lens with respect to the d-line counting from the object side.

In addition, the distance between the upper surfaces of the shafts, which changes due to zooming in the construction data, is in the high magnification state [T].
It is the actual surface spacing between the zoom groups GrA, GrB, GrC in the middle (intermediate focal length state) [M] to low magnification state [W]. Each state in the sub-scanning direction (that is, z-axis direction)
Effective focal length f of entire system corresponding to [T], [M], [W], magnification β, and effective F number EFFN on the image side when f = 79.767
O is also shown. Further, in Table 1, the mirror rotation angle θ (°) in the case where the second embodiment is applied to this example
And the object height Y in the main scanning direction corresponding to the mirror rotation angle θ
(mm) is shown.

<< Construction Data of Examples >> f = 79.767 to 63.447 to 53.974 β = -0.669 to -0.558 to -0.478 EFFNO = 5.21 [plane] [radius of curvature] [interval between top surfaces] [refractive index] S1 r1 =- 49.542 d1 = 4.000 N1 = 1.61659 S2 r2 = 844.495 d2 = 10.000 S3 r3 = -630.064 d3 = 8.000 N2 = 1.61800 S4 r4 = -83.652 d4 = 1.000 S5 r5 = 186.095 d5 = 8.000 N3 = 1.61800 S6 r6 = -186.302 d6 = 0.620 S7 r7 = 70.451 d7 = 7.000 N4 = 1.61800 S8 r8 = 312.890 d8 = 2.620 S9 r9 = 36.382 d9 = 8.000 N5 = 1.69100 S10 r10 = 76.584 d10 = 4.000 N6 = 1.66446 S11 r11 = 26.274 d11 = 33.000 S12 r12 = ∞ ( Mirror M) d12 = 12.000 S13 r13 = ∞ (Aperture A) d13 = 0.500 to 11.411 to 16.648 S14 r14 = 18.893 d14 = 4.100 N7 = 1.76200 S15 r15 = 99.555 d15 = 1.500 S16 r16 = -55.909 d16 = 4.800 N8 = 1.75520 S17 r17 = 20.006 d17 = 1.800 S18 r18 = 51.415 d18 = 2.600 N9 = 1.74350 S19 r19 = -45.455 d19 = 0.900 S20 r20 = -213.315 d20 = 2.600 N10 = 1.78100 S21 r21 = -56.193 d21 = 1.800 ~ 6.580 ~ 11.189 S22 r22 = 46.974 d22 = 3.200 N11 = 1.75690 S23 r23 = -28.957 d23 = 1.200 S24 r 24 = -29.053 d24 = 1.000 N12 = 1.65446 S25 r25 = 60.000 d25 = 2.000 S26 r26 = -23.796 d26 = 1.100 N13 = 1.74000 S27 r27 = 54.165 d27 = 21.500 ~ 9.732 ~ 2.347 S28 r28 = 55.316 d28 = 6.500 N14 = 1.74400 S29 r29 = -33.011 d29 = 1.700 N15 = 1.60342 S30 r30 = -323.724 d30 = 8.425 ~ 4.503 ~ 2.040 S31 r31 = ∞ d31 = 3.000 N16 = 1.51680 (filter 2) S32 r32 = ∞ Σd = 168.465 to 168.465 to 168.465

[0044]

[Table 1]

[0045]

As described above, in the first to third inventions, the exit pupil of the object side lens group and the entrance pupil of the image side lens group are made to substantially coincide with each other. Even if is flat, high-speed scanning without curvature is possible. Further, since the object side lens group and the image side lens group can be configured only by a rotationally symmetric spherical system which is inexpensive and easy to manufacture, it can be realized at low cost. Therefore, by using the scanning optical system according to the present invention, cost reduction of the scanning device can be effectively realized.

Further, in the first and third inventions, the zoom optical system is used as the lens group of the object side lens group and the image side lens group whose optical path does not change in the main scanning, thereby changing the magnification in the sub-scanning direction. Since the configuration is simple, it is possible to perform zooming in the sub-scanning direction at low cost without increasing the size of the scanning optical system. Further, in the second and third inventions, the rotation speed and the rotation range of the mirror are made variable so that the magnification is changed in the main scanning direction. Therefore, the size of the scanning optical system can be increased. Therefore, it is possible to perform zooming in the main scanning direction at low cost.

Further, according to the first to third inventions, since it is not necessary to process the image once captured on the image pickup surface, the convenience is improved and the captured image is flexible. Correspondence becomes possible. Further, according to the third invention,
It is possible to change the magnification in both main scanning and sub-scanning directions, and it is possible to achieve both isotropic and anisotropic magnification and high magnification ratio at the same time. Correspondence becomes possible.

[Brief description of drawings]

FIG. 1 is a perspective view schematically showing the basic configuration of a scanning optical system embodying the present invention.

FIG. 2 is a lens configuration diagram showing a sub-scanning section in a high magnification state and a low magnification state of the first embodiment.

FIG. 3 is a lens configuration diagram showing a main scanning section when a mirror rotation angle θ = 45 ° in the second embodiment.

FIG. 4 is a lens configuration diagram showing a main scanning section when a mirror rotation angle θ = 48.5 ° in the second embodiment.

FIG. 5 is a lens configuration diagram showing a main scanning section when a mirror rotation angle θ = 41.5 ° according to a second embodiment.

[Explanation of symbols]

 1 ... Film screen 2 ... Filter 3 ... Line CCD Gr1 ... Image side lens group Gr2 ... Object side lens group GrA, GrB, GrC ... Zoom group M ... Mirror A ... Aperture

Claims (3)

[Claims] 1. An object-side lens group that collects light from an object, and a mirror that performs main scanning for imaging an object by deflecting light that has passed through the object-side lens group.
A scanning optical system comprising: an image-side lens group that forms both on-axis light and off-axis light in the sub-scanning direction, which are deflected by the mirror, on an imaging surface, the object-side lens group, the image Among the side lens groups, a zoom optical system is used for a lens group whose optical path does not change in the main scanning, and the exit pupil of the object side lens group and the entrance pupil of the image side lens group are substantially matched. Scanning optical system. 2. An object-side lens group that collects light from an object, and a mirror that performs main scanning to image the object by deflecting light that has passed through the object-side lens group.
A scanning optical system comprising: an image-side lens group that forms both on-axis light and off-axis light in the sub-scanning direction, which are deflected by the mirror, on an image pickup surface. A scanning optical system characterized in that the scanning speed and range are variable, and that the exit pupil of the object side lens group and the entrance pupil of the image side lens group are substantially matched. 3. An object side lens group that collects light from an object, and a mirror that performs main scanning for imaging the object by deflecting the light that has passed through the object side lens group.
A scanning optical system comprising: an image-side lens group that forms both on-axis light and off-axis light in the sub-scanning direction, which are deflected by the mirror, on an imaging surface, the object-side lens group, the image Among the side lens groups, a zoom optical system is used for the lens group whose optical path does not change in the main scanning, the speed and range of the main scanning are made variable by rotation control of the mirror, and the exit pupil of the object side lens group is A scanning optical system in which the entrance pupil of the image-side lens group is substantially matched.