JPH06250119A - Imaging element - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain an imaging element with small chromatic aberration and without difficulty in manufacturing the lens itself. [Structure] A large number of image forming elements are arranged in a direction perpendicular to a valley line where the reflecting surfaces intersect on a plane, with a pair of reflecting surfaces placed so as to form a valley with an apex angle of π / 2 (radian). The reflecting surface pair row 3 and the reflecting surface pair row are arranged in parallel at the same distance from the reflecting surface pair row,
In addition, two rows of convex lens arrays 1 and 2 are arranged in the same array direction as the reflective surface pair row and at a period larger than the reflective surface pair row.
Composed of and. Further, in addition to the configuration, it is configured to have a reflecting means which is arranged so as to face each of the convex lens arrays and which changes an optical path passing through each of the convex lens arrays.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming element used in a line image forming apparatus in a facsimile, an electronic copying machine, an LED printer or the like.

[0002]

2. Description of the Related Art In facsimiles, copiers, LED printers, etc., an image forming element for projecting an object on a line onto a sensor or a photosensitive drum at an equal magnification is used. An imaging element used in this field is a cylindrical transparent body,
A lens array in which a large number of rod-shaped lens elements whose refractive index continuously decreases from the axis to the outside are arranged in parallel, for example, JP-B-49-8893 and JP-A-57-1049.
No. 23, JP-A-57-66414, etc., a spherical lens array laminated in a multilayer structure,
JP-A-61-1210319 and JP-A-56-11
No. 7201, No. 56-126801, No. 56-140301, No. 56-1490.
02, JP-A-60-254018, JP-A-60-254019, and JP-A-60-254020.
JP-A-61-233714 and JP-A-62.
-91902, and JP-A-62-201417.
There is known a system in which an optical system unit in which a roof prism (or a roof mirror) and a lens are combined so as to form an erecting equal-magnification image and are arrayed in an array, as disclosed in Japanese Patent Laid-Open Publication No. 2003-242242.

[0003]

The imaging element using the gradient index rod lens shown in the above method requires a long time to manufacture the gradient index rod lens, and the integration of the refraction angles of the rays is large. Since chromatic aberration is likely to occur and it is difficult to control the refractive index distribution in the cross section of the rod-shaped lens, there is a difficulty in manufacturing the rod-shaped lens. Although the image forming element of the method does not cause any difficulty in the manufacture of the spherical lens itself, there is a difficulty in the assembling process of accurately aligning the lens axes of three or more spherical lenses, and the integration of the refraction angles of the light rays is difficult. Since it becomes large, there is a drawback that the chromatic aberration becomes large. The line imaging device of the method has a drawback that it is difficult to align the axis of the roof prism (or roof mirror) and the lens.

[0004]

Therefore, the present invention has been completed as a result of studying to develop an image-forming element which has a small chromatic aberration and does not cause difficulty in manufacturing the lens itself. However, in the image forming element, a continuous linear equal-magnification image is formed by combining the image forming action of the two-row convex lens array and the inverting action of the pair of orthogonal reflecting surfaces.

More specifically, in the imaging element according to the first invention of the present application, a pair of reflecting surfaces placed so as to form a valley with an apex angle of π / 2 (radian) is formed on a plane. A large number of reflective surface pairs arranged in a direction perpendicular to the intersecting valley lines, and arranged in parallel at an equal distance from the reflective surface pair row, and larger than the reflective surface pair row in the same array direction as the reflective surface pair row. It is composed of two rows of convex lens arrays arranged in a cycle.

The imaging element according to the second invention of the present application is
A pair of reflective surface pairs in which a plurality of pairs of reflective surfaces placed so as to form a valley with an apex angle of π / 2 (radian) are arrayed in a direction perpendicular to the valley line where the reflective surfaces intersect, and Two rows of convex lens arrays, which are arranged in parallel at equal distances from the reflecting surface pairs, and are arranged in the same direction as the reflecting surface pairs, at a period larger than that of the reflecting surface pairs, and face each of the convex lens arrays. And a reflecting means for changing the optical path passing through each of the convex lens arrays.

[0007]

In the line image forming element composed of the lens array, each unit forms an erect image, which is an essential condition for forming a continuous line image. In the present invention, the burden of the lens is reduced by the reflecting action of the pair of orthogonal reflecting surfaces, and an imaging element with less chromatic aberration can be obtained, and the image forming action of the reflecting surface pair having a narrow width is achieved by the lens and the reflecting surface pair. We have succeeded in facilitating the alignment between the columns and making the imaging element easy to assemble.

Also, by combining reflecting means for facing each of the lens arrays and changing the optical path passing therethrough, the positions of the object plane and the image plane are changed, and the image is prevented from being inverted in any direction. be able to.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of the image forming device according to the present invention will be described in detail below with reference to the drawings. 1 is a perspective view showing an embodiment of an imaging element according to the first invention of the present application, FIG. 2 is a plan view of the yz plane of the imaging element of FIG. 1, and FIG. 3 is a plan view of its xy plane. Reference numerals 1 and 2 in these drawings denote convex lenses, each having an optical axis parallel to the y axis, arranged in parallel in the z axis direction and arranged in the x axis direction in a one-to-one correspondence. Reference numeral 3 denotes an array of orthogonal reflecting surfaces. Each reflecting surface is parallel to the z-axis, forms an angle of ± 45 ° with the y-axis, and is aligned in the x-axis direction. The convex lenses 1 and 2 have the same focal length,
The size and the shape are the same, and the object plane 6 and the image plane 7 are at positions separated by the focal length from the respective lenses.

FIG. 4 is a plan view of the xy plane for explaining the optical action of the orthogonal reflecting surface pairs. The light incident on the reflecting surfaces orthogonal to each other is reflected by the two surfaces, the traveling direction is reversed, and the light returns to the incident direction. This is the reversal action of the reflective surface pair. Further, FIG. 5 is a plan view of the xy plane for explaining the action of the array of reflecting surface pairs. The light emitted from the point O is inverted by each pair of reflecting surfaces and returns to the vicinity of the point O again. Since the positional deviation at this time is the width of the reflecting surface pair at the maximum, it is possible to focus the reflected light on the point O by shortening the arrangement interval of the reflecting surface pairs and narrowing the width. This is the imaging action of the reflective surface pair.

In the imaging element shown in FIGS. 1 to 3, the light entering the convex lens 1 from a point on the object plane 6 is converted into parallel light by the action of the convex lens 1 and is formed on the reflecting surface pair row 3. Go to Here, the reflective surface pair row 3 has the same action as reflection by a normal plane in the zy plane, and the reflected light is directed to the array of the convex lens 2 as parallel light, but at this time, the reflected light is in the xy plane described above. Due to the image forming action, it reaches the convex lens 2 existing at the same position in the xy plane. Further, this ray is parallel light in the xy plane, which is parallel to and opposite to that before the reflection due to the inverting action of the pair of reflecting surfaces, so that the convex lens 2
Is focused on the image plane 7 at the same x coordinate as the light emitting point on the object plane 6. The same holds for the rays that pass through the other convex lenses of the lens array, and all the rays are focused on the same point, as shown in FIG. In this way, an upright image can be obtained in the x direction, which is shown in FIG.
As shown by, the image becomes an inverted image in the z direction.

That is, (1) Position by convex lens 1-
Angle conversion, (2) Inversion of angle by reflecting surface pair 3, (3)
By the angle-position conversion by the convex lens 2, an erecting equal-magnification image in the x-axis direction can be obtained. In addition, since the angle is inverted by reflection having no chromatic aberration, the overall optical system has little chromatic aberration. Further, since the image forming action of the reflecting surface pair row 3 is used to guide the light rays from the convex lens 1 to the convex lens 2, x of the reflecting surface pair row 3 and the convex lens array is used.
An optical system that is easy to assemble can be obtained because alignment in directions is unnecessary.

Next, the structure of the imaging element according to the second aspect of the present invention will be described with reference to FIGS. 6 is a perspective view showing an embodiment of an imaging element according to the second invention of the present application, FIG. 7 is a plan view of the yz plane of the imaging element of FIG. 6, and FIG. 8 is a plan view of its xy plane. This imaging element is composed of the convex lenses 1 and 2 of FIG.
Of the reflective surfaces 4 and 5 that are ± 45 ° with the y-axis behind the array of
The transparent member having is formed by integrally forming 8 and 9 with the lens array, and the other points are the same as those of the imaging element of FIG. The positions of the object plane 6 and the image plane 7 are changed from the positions of their mirror images 6'and 7'by the reflecting surfaces 4 and 5, and they become parallel to each other, and the images become erect images, which increases the practicality.

FIG. 9 shows the transparent members 8 and 9 on which the lens array is formed. As mentioned above, the imaging action of the reflective surface pair row 3 is accompanied by a maximum deviation of the width of the reflective surface pair. Therefore, if the convex lenses are lined up without a gap, the light rays from the pair of adjacent lenses are mixed together near the boundary, and stray light is generated.
As shown in, a light shielding portion 12 having a width equal to the width of the reflective surface pair is provided between the lenses. Although it is preferable to provide the light shielding portion 12 also in the other embodiments, if the width of the pair of reflecting surfaces is smaller than the width of the lens by one digit or more, the contrast of the image is less deteriorated even without the light shielding portion 12.

Reflecting surface pair 3 in the embodiment of FIGS. 1 and 6.
Can be manufactured by vapor-depositing a metal such as aluminum on a plate having a right-angled groove. 10 is a perspective view showing another embodiment of the imaging element according to the second invention of the present application, and FIG. 11 is a plan view of the yz plane of the imaging element of FIG. In this embodiment, the array of the convex lenses 1 and 2 and the reflective surface pair row 3 are formed on the transparent member 10 which is integrated. The pair of reflecting surfaces 3 here is a rectangular prism formed on the transparent member 10 and coated with a reflecting film, and the lens array is arranged from the width of the image of each convex lens secured by total reflection of the rectangular prism. If the pitch is shortened, the coating of the reflective film can be omitted and the manufacturing cost can be reduced. However, this makes the image darker and tends to cause uneven brightness, so care must be taken in the design.

FIG. 12 is a perspective view showing still another embodiment of the imaging element according to the second invention of the present application, and FIG. 13 is FIG.
3 is a plan view of the yz plane of the imaging element of FIG. In this embodiment, in addition to the array of convex lenses 1 and 2 and the reflective surface pair row 3, the reflective surfaces 4 and
5 is also integrally formed by the transparent member 11. Further, the reflecting surfaces 4 and 5 are optically arranged between the lens arrays 1 and 2 and the reflecting surface pair row 3, which is different from the other embodiments described above. By integrating all the optical elements in this way, the assembly labor can be greatly reduced.

In the drawings described above, for the sake of simplicity, the configuration of the image forming element according to the present invention is shown using a lens array in which three lenses are lined up. It is usually a lens array in which hundreds of lenses are lined up. Even in such a case, the operation is not different from that described above. FIG. 14 is a perspective view showing the structure of an example of a line imaging apparatus using an imaging element according to the present invention in a partial cross section, and FIG. 15 is a cross sectional view of the yz plane thereof. This device is one in which the image forming element shown in FIGS. 6 to 8 is housed in a case, and the width of the reflecting surface pair row 3 is 0.
Using a polymethylmethacrylate transparent plate with a 5mm prism array formed with a reflection-enhancing coating, use 10 square lenses 1 and 6 of 6mm square with a radius of curvature of 8mm on a prism made of polymethylmethacrylate. The transparent members 8 and 9 are used. It was confirmed that an image of an optical grating of 5 lp / mm could be actually projected using this line imaging device.

[0018]

As described above, the imaging element according to the present invention obtains a continuous image on a line by using an array of two rows of convex lenses and a row of reflecting surfaces. It is easy, and since the integration of the refraction angles accompanying image formation is small, it is possible to obtain an image with little chromatic aberration.

Further, the convex array, the pair of reflecting surfaces, and the reflecting means for changing the optical path can be integrally formed by the transparent member, which greatly simplifies the production of the element and the assembly of the apparatus. can do.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of an embodiment of an imaging element according to the first invention of the present application.

FIG. 2 is a plan view of a yz plane of the imaging element of FIG.

FIG. 3 is a plan view of an xy plane of the imaging element of FIG.

FIG. 4 is an explanatory diagram for explaining an inversion action of a pair of orthogonal reflecting surfaces.

FIG. 5 is an explanatory diagram for explaining an image forming action of pairs of orthogonal reflecting surfaces.

FIG. 6 is a perspective view showing a configuration of an embodiment of an imaging element according to the second invention of the present application.

7 is a plan view of the yz plane of the imaging element of FIG.

8 is a plan view of the xy plane of the imaging element of FIG.

9 is a perspective view showing a configuration of a transparent member used in the image forming element of FIG.

FIG. 10 is a perspective view showing the configuration of another embodiment of the imaging element according to the second invention of the present application.

11 is a plan view of the yz plane of the imaging element of FIG.

FIG. 12 is a perspective view showing the configuration of still another embodiment of the imaging element according to the second invention of the present application.

13 is a plan view of the yz plane of the imaging element of FIG.

FIG. 14 is a perspective view, partly in cross section, showing the configuration of an example of a line imaging apparatus using an imaging element according to the present invention.

15 is a plan view of the yz plane of the line imaging device in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Convex lens (array) 2 ... Convex lens (array) 3 ... Reflective surface pair row 4 ... Reflective surface 5 ... Reflective surface 6 ... Object surface 6 '... Object surface mirror image 7 ... Image surface 7' ... Image surface mirror image 8 ... Transparent member 9 ... Transparent member 10 ... Transparent member 11 ... Transparent member 12 ... Light-shielding portion

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location G02B 3/00 A 8106-2K 17/08 Z 9120-2K H04N 1/028 Z 8721-5C 1 / 036 A 8721-5C

Claims (2)

[Claims] 1. A plurality of reflecting surfaces, each having a pair of reflecting surfaces arranged to form a valley having an apex angle of π / 2 (radian), are arranged on a plane in a direction perpendicular to a valley line where the reflecting surfaces intersect. And a pair of convex lens arrays that are arranged in parallel at an equal distance from the reflecting surface pair row and that are arranged in a direction equal to the reflecting surface pair row and at a period larger than the reflecting surface pair row. Image element. 2. A reflective surface formed by arranging a plurality of pairs of reflective surfaces placed so as to form a valley having an apex angle of π / 2 (radian) in a direction perpendicular to a valley line where the reflective surfaces intersect. A pair of rows, a two-row convex lens array arranged in parallel at an equal distance from the reflection surface pair row, and arranged in a direction equal to the reflection surface pair row at a period larger than the reflection surface pair row; and the convex lens. An image forming element, which is arranged so as to face each of the arrays and which comprises a reflecting means for changing an optical path passing through each of the convex lens arrays.