JPH02262118A - Unmagnification image forming element - Google Patents

Abstract

PURPOSE:To uniform a resultant light quantity distribution by forming individual corner cubes of a corner cube mirror lens array in the same aperture shape and arranging them so that the optical axis centers of the respective corner cubes cross one another on a read scanning line. CONSTITUTION:Corner cube mirror lens arrays 11 constituted of (n) columns having an array period (p) are arranged while shifting by p/n each. Consequently, light quantity distributions formed by the individual corner cube mirror lens arrays 11 are distributions which shift in cycle by p/n each, as well and the cycle of the resultant light quantity distribution is also p/n. Further, all the corner cubes 12 have the same aperture shape and are disposed so that the optical axis centers S of the respective corner cubes 12 are read and cross one another on the read scanning line 13. Consequently, the quantities fetching effective light incident on the individual corner cubes 12 are all equal and the difficulty in design for optimizing the light quantity period irregularity of the corner cube mirror lens arrays 11 is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a 1-magnification imaging element used in a scanner section of a copying machine, facsimile machine, image scanner, or the like.

2. Description of the Related Art Conventionally, as a same-magnification imaging element, there is a roof mirror lens array used in image reading devices and the like. As a first conventional example, there is one filed by the present applicant in Japanese Patent Application No. 143086/1986 under the name of roof mirror lens array.

As shown in FIG. 5, a diaphragm plate 4 is provided between the roof mirror lens array 1 and the lens array 2, with a protrusion 3 formed at one end and having two openings with different widths. , aiming to make the combined light amount distribution uniform.

Problems to be Solved by the Invention In the case of the above-described device, since the period of the roof mirror lens array 1 and the period of the diaphragm plate 4 are the same, periodic light intensity unevenness occurs.

Therefore, in order to eliminate such unevenness in the amount of light, a patent application
No.-23024 has been filed by the present applicant as a 1-magnification imaging element. As shown in FIG. 6, a corner cube mirror lens array 6 is constructed by arranging a large number of tetrahedral corner cubes 5 in a direction perpendicular to the optical axis with an arrangement period P. 6 in a direction perpendicular to each other in the arrangement direction (Y-axis direction) and the optical axis direction (X-axis direction).
Arranged in n columns (here, n = 3) by shifting the period of
Furthermore, a lens array 7 and a half mirror 8 as an optical path separation mirror are provided corresponding to each row of the corner cube mirror lens arrays 6 arranged in n rows. As a result, the light from point A on the document surface 9 passes through the half mirror 8 and the lens array 7, and then is reflected by the corner cube mirror lens array 6.
B on the image plane 10 whose optical path is changed by the half mirror 8
Focus on a point.

As shown in FIG. 3, by arranging the corner cube mirror lens arrays 6 consisting of n rows offset from each other by p/n, the light intensity distribution formed by the individual corner cubes 5 is I)/n. , and the period of the combined light quantity distribution is p/n. Therefore, compared to the conventional method where the periodic unevenness of the composite light intensity distribution was p, the periodic unevenness can be made even finer by 1/n, and as a result, it is actually uniform with almost no periodic unevenness. It becomes possible to obtain an image with a high density.

However, in this case, in order to focus the corner cube mirror lens arrays 6 arranged in n rows on the reading scanning line of the document surface 9, the aperture shapes of the individual corner cubes 5 constituting the corner cube mirror lens arrays 6 are changed. Each row must be formed differently, which makes the design extremely difficult.

In addition, such a same-magnification imaging element can be used in an image reading device, especially,
When reading in a facsimile or digital copying machine, if there is periodic unevenness in the amount of light in the 1-magnification imaging element, even if the document itself is maintained at a uniform density, the image surface where it is being read will be affected. It appears as bright and dark information corresponding to the period, and especially in the case of a copying machine, it appears as white streaks or black streaks in the sub-scanning direction. As a result, the finer the period of such shading becomes, the more difficult it becomes to read the information on the copied document.

Means for Solving the Problem Therefore, in order to solve such problems, claim 1
The described invention includes a corner cube mirror lens array in which one side connecting the vertices of a corner cube having at least three reflective surfaces intersects the optical axis direction at right angles, and a large number of corner cube mirror lenses are arranged in a straight line in the same plane with an arrangement period p. The corner key = 5-6 tube mirror lens arrays are arranged in n rows with a period of p/n shifted in a direction orthogonal to each other in the arrangement direction and the optical axis direction, and All of the corner cubes of the cube mirror lens array have the same aperture shape and are arranged so that the optical axis centers of the respective corner cubes intersect with the reading scanning line, and the corner cube mirror lenses arranged in n rows A lens array and an optical path separation mirror were provided corresponding to each column of the array.

The invention according to claim 2 provides a roof mirror lens array in which a large number of roof mirror lenses each having at least two reflective surfaces are arranged at an arrangement period p in a direction perpendicular to the optical axis direction, and the roof mirror lens array is The roof mirror lenses of the roof mirror lens array are arranged in n rows with a period of p/n shifted in a direction perpendicular to each other in the arrangement direction and the optical axis direction, and all of the roof mirror lenses of the roof mirror lens array have the same aperture shape. The optical axis centers of each roof mirror lens are arranged so as to intersect with the reading scanning line,
A lens array and an optical path separation mirror were provided corresponding to each row of the roof mirror lens array arranged in n rows.

Accordingly, in the invention as claimed in claim 1, a corner cube mirror lens array consisting of n rows with an arrangement period p.
By shifting the corner cube mirror lens array by /n, the light intensity distribution formed by each corner cube mirror lens array is also p.
The distribution is shifted by a period of /n, and as a result, the period of the combined light quantity distribution is also p/n. In addition, since all corner cubes have the same aperture shape and are arranged so that the optical axis centers of each corner cube intersect on the reading scanning line, the effective amount of light taken in by each corner cube is Moreover, the design difficulty of optimizing the light amount periodic unevenness of the corner cube mirror lens array is eliminated.

Furthermore, in the invention set forth in claim 2, by configuring the same-magnification imaging element using a roof mirror lens instead of the corner cube in the invention set forth in claim 1, it is possible to eliminate periodic unevenness in the combined light amount distribution. Moreover, the design difficulty of optimizing the periodic unevenness of the light quantity of the roof mirror lens array is also eliminated.

Embodiment First, an embodiment of the invention as claimed in claim 1 will be explained based on FIGS. 1 to 3.

The corner cube mirror lens array 11 is arranged such that one side connecting the vertices of a corner cube 12 having at least three reflective surfaces intersects the optical axis direction (X-axis direction) at right angles and is arranged on a straight line 1 in the same plane with an arrangement period p. A large number of them are arranged. The corner cube mirror lens arrays 11 are arranged in n rows shifted by a period of p/n in a direction perpendicular to the arrangement direction (Y-axis direction) and the optical axis direction. Each of the corner cubes 1 of the corner cube mirror lens array 11
All of the corner cubes 2 have the same aperture shape, and the optical axis center S of each corner cube 12 is read and scanned by the scanning line 13.
They are arranged so that they intersect at the top. A lens array 14 and a half mirror 15 as an optical path separation mirror are provided corresponding to each row of the corner cube mirror lens array 11 arranged in n rows.

In such a configuration, light from the document surface 9 passes through the half mirror 15, is converted into parallel light by the lens array 14, and is retroreflected by the corner cube mirror lens array 11. Then, the light passes through the lens array 14 again and is reflected by the half mirror 15, so that an image is formed on the image plane 10 at a point B that is conjugate with the point A on the document surface 9.

In this case, when the light amount distribution of each corner cube mirror lens array 11 on the image plane 10 and their combined light amount distribution are shown in relation to the arrangement direction, the configuration is as shown in FIG. 2. As a result, the light intensity distribution of each corner cube mirror lens array 11 from the first column to the nth column is the same as the arrangement period p, but in the case of this embodiment, the corner cube mirror lens array 11 of each column are arranged so that they are shifted by p/3, the light intensity distribution of each corner cube mirror lens array 11 is shifted in phase by p/3 from each other, as shown in FIG. 3, and as a result, , the periodic unevenness of these three combined light intensity distributions is also p
/3. This means that while the periodic unevenness of the conventional composite light amount distribution is p, which is the same as the arrangement period of the corner cube mirror lens array 11, in the present invention, it is 1/3, and as a result, the period of the composite light amount distribution is 1/3. It is possible to further reduce unevenness and obtain a uniform image.

In addition, in the case of this embodiment, the individual corner cubes 12 constituting the corner cube mirror lens array 11 are formed to have the same aperture shape, and are arranged so that their optical axis centers S intersect on the reading scanning line. It is possible to make the amount of all effective light taken in the same, which makes the corner cube lens design made by the lenses of the lens array 14 corresponding to each corner cube 12 and the corner cube 12 even more advanced than before. It can be easily done.

Next, an embodiment of the invention according to claim 2 will be described based on FIG. 4. This embodiment describes the case where the corner cube 12 in the embodiment of the invention described in claim 1 is replaced with a roof mirror lens, and there is no difference in other configurations.

That is, the roof mirror lens array 16 is configured by arranging roof mirror lenses 17 having at least two reflective surfaces in a direction (Y-axis direction) orthogonal to the optical axis direction (X-axis direction). All of these individual roof mirror lenses 17 have the same aperture shape, and are arranged so that their optical axis centers S intersect on the reading scanning line 13. Therefore, in the case of this embodiment as well, it is possible to reduce periodic unevenness in the amount of light, and since the individual roof mirror lenses 17 have the same aperture shape, it is easier to design a lens compared to the conventional one. can do.

Effects of the Invention In the invention described in claim 1, all the individual corner cubes of the corner cube mirror lens array have the same aperture shape and are arranged so that the optical axis centers of the respective corner cubes intersect on the reading scanning line. By doing this,
The amount of effective light taken in by each corner cube is all equal, and furthermore, it is possible to eliminate the conventional design difficulty of optimizing the periodic unevenness of the light amount of the corner cube.

In the invention according to claim 2, all the individual roof mirror lenses of the roof mirror lens array have the same aperture shape and are arranged so that the optical axis centers of the respective roof mirror lenses intersect on the reading scanning line. As a result, the amounts of effective light taken in by the individual roof mirror lenses are all equal, and furthermore, it is possible to eliminate the conventional design difficulty of optimizing the irregularities in the period of light in the roof mirror lenses.

[Brief explanation of drawings]

FIG. 1 is an optical path diagram showing an embodiment of the invention as claimed in claim 1;
FIG. 2 is a configuration diagram of the corner cube mirror lens array viewed from the front axis direction, FIG. 3 is a waveform diagram showing the combined light amount distribution obtained on the image plane, and FIG. FIG. 5 is an optical path diagram showing the first conventional example, FIG. 6 is a perspective view showing the second conventional example, and FIG. 7 is an optical path diagram showing the second conventional example. 11... Corner cube mirror lens array, 12
...Corner cube, 13...Reading scanning line, 1
4... Lens array, 15... Optical path separation mirror 16
...Roof mirror lens array, 17...Roof mirror lens, S...Optical axis center Applicant Ricoh Co., Ltd., wmx

Claims (1)

[Claims] 1. Corner cube mirrors in which one side connecting the vertices of a corner cube having at least three reflective surfaces intersects the optical axis direction at right angles, and a large number of corner cube mirrors are arranged in a straight line in the same plane with an arrangement period p. A lens array is provided, and the corner cube mirror lens array is arranged in n rows with a period of p/n shifted in a direction orthogonal to each other in the arrangement direction and the optical axis direction, and the corner cube mirror lens array All of the corner cubes of each of the n
A 1-magnification imaging element characterized in that a lens array and an optical path separating mirror are provided corresponding to each row of corner cube mirror lens arrays arranged in rows. 2. A roof mirror lens array is provided in which a large number of roof mirror lenses each having at least two reflective surfaces are arranged in a direction perpendicular to the optical axis direction with an arrangement period p, and the roof mirror lens array is arranged in a direction perpendicular to the optical axis direction. The roof mirror lenses of each of the roof mirror lens arrays are arranged in n rows shifted by a period of p/n in a direction orthogonal to each other in the optical axis direction, and all of the roof mirror lenses of each of the roof mirror lens arrays have the same aperture shape, and each of the roof mirror lenses has the same opening shape. The optical axis centers of the mirror lenses are arranged so as to intersect with the reading scanning line, and a lens array and an optical path separating mirror are respectively provided corresponding to each row of the roof mirror lens array arranged in n rows. Features: 1-magnification imaging element.