JPH02201414A - Aperture plate in 1-magnification imaging element - Google Patents

Abstract

PURPOSE:To decrease the interval between a plate lens and a roof mirror array and to reduce the attenuation of light, and to obtain a bright light image which is good in light utilization efficiency and has no irregularity in light quantity by cutting off ghost like stray light effectively by light shield walls which are positioned at opening parts of the stop plate and reducing the thickness of the stop plate. CONSTITUTION:The light shield walls 62 are provided at the respective opening parts 61 of the stop plate 6 in parallel to the optical axis and the thickness d1 of the stop plate 6 is reduced to remove the stray light affecting the image forming performance, thereby forming a bridge 63 small. When the constitution of a lens 4a of the plate lens 4 is determined, the limit incidence angles of reflected ghost like stray light beams which are reflected once and twice are determined by simulation such as ray tracing. The plate thickness d1 of the stop plate 6 is reduced to specific thickness on the assumption of the angles and sufficient intervals of the light shield walls 62 for cutting off the ghost like stray light at the opening parts 61 of the stop plate 6 are determined. Consequently, the interval between the plate lens 4 and roof mirror array 5 is decreased to reduce the attenuation of light and improve the light utilization efficiency, thereby enabling bright unmagnification image formation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a 1-magnification imaging element having multiple lenses, and is applicable to facsimiles, copying machines, etc. (Prior art) Conventionally, facsimile reading devices, In the exposure section of the copying machine,
A 1x imaging element is arranged, and this 1x imaging element is
Equipped with a right-angle mirror that separates the object side optical path and the image side optical path,
The optical image of the original provided in the object-side optical path of this right-angle mirror is imaged as an erect equal-magnification image at a position provided in the image-side optical path of the right-angle mirror, and this configuration was developed before this application. It is publicly known.

This equal-magnification imaging element is arranged between the right-angle mirror, a plate lens made up of a plurality of lens units, a roof mirror array made up of a plurality of roof mirror units, and the plate lens and the roof mirror array. It consists of an aperture plate.

Stray light that causes a decrease in imaging performance and an increase in light intensity unevenness in a 1-magnification imaging element, i.e., twice-reflected ghost-like stray light that has optical information, and has a clear light intensity peak that cannot be optical information. - Double-reflected ghost-like stray light exists, and conventionally, in order to remove these stray lights, as shown in FIG. 6, the thickness of the aperture plate 6A provided between the plate lens and the roof mirror array is dl or the opening part 6 of the aperture plate 6A
It is controlled by the thickness d2 of the width of the crosspiece 63A provided between IA, and the shape of the aperture plate is such that both the thickness dI of the aperture plate and the thickness d2 of the width of the crosspiece are thick.

[Problem to be solved by the invention]

In the above-described same-magnification imaging element, the present invention shortens the length of the optical path that passes through the plate lens and is reflected by the roof mirror.
The object of the present invention is to provide a configuration of an aperture plate with high light utilization efficiency, which can reduce the attenuation of the amount of light and eliminate the stray light that causes the deterioration of the imaging performance and increase of the unevenness of the amount of light as described above. .

[Means to solve the problem]

In order to achieve the above object, the present invention provides a right-angle mirror that separates an object-side optical path and an image-side optical path, a plate-shaped lens in which a plurality of lenses are arranged opposite to the right-angle mirror, and a plate-shaped lens that In a 1-magnification imaging element consisting of a roof mirror array arranged corresponding to each lens, and an aperture plate provided between the plate lens and the roof mirror array, each aperture of the aperture plate has a light beam. It is characterized by providing a plurality of light-shielding walls parallel to the axis, reducing the thickness of the diaphragm plate, and eliminating stray light that affects imaging performance.

[For production]

In the configuration of the present invention, ghost-like stray light is effectively blocked by a plurality of light shielding walls located at the opening of the diaphragm plate, and by reducing the thickness of the diaphragm plate, the distance between the plate lens and the roof mirror array is brought closer. However, it is possible to obtain a bright optical image with less light attenuation, high light utilization efficiency, and no unevenness in the amount of light.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 3 shows a 1-magnification imaging element to which the present invention can be applied.

1 is a right-angle mirror for optical path separation, and one surface 1a of the right-angle mirror 1 faces the document 2 on the document placement glass, and the other surface 1b of the right-angle mirror 1 is an image-forming surface 3 for an erect, same-size image of the document. is facing. 4 is a plate-shaped lens, which includes a plurality of lenses 4a,
4a... are arranged integrally in the longitudinal direction. 5 is a roof mirror array, which includes a plurality of roof mirrors 5a.

5a... are arranged integrally in the longitudinal direction, and the lens 4a and the roof mirror 5a are combined in correspondence with each other and constitute one unit of a 1-magnification imaging element.

The right-angle mirror 1, plate lens 4, and roof mirror array 5 are supported by a storage case in which an object-side opening and an image-side opening are formed on both sides of the right-angle mirror 10.

A fourth lens is provided between the plate lens 4 and the roof mirror array 5.
As shown in the figure, a diaphragm plate 6 is arranged to prevent ghost-like stray light that causes a decrease in imaging performance and an increase in unevenness in the amount of light.

Next, ghost-like stray light blocked by the aperture plate 6 of the present invention will be explained.

As shown in FIG. 7, ghost-like stray light is caused by the lens 4a8, which is one unit of the same-magnification imaging element, and the roof mirror 5a.
Irrespective of the + combination, the light rays incident from the adjacent lens 4a undergo regular reflection and then form an image on the imaging plane, such as double-reflected ghost-like stray light, or as shown in FIG. 8, the roof mirror 5a. Although it cannot be optical information such that a ray of light that is incident nearly perpendicular to , returns to the imaging plane after one reflection, there is a single-reflection ghost-like stray light that has a clear light intensity peak. In order to restrict the aperture 61 of the diaphragm plate 6 for removing these stray lights, conventionally the thickness d of the diaphragm plate 6 was basically changed, and the crosspieces 63 between the apertures 61 were Width d
2 has been changed.

As shown in FIG. 1, the diaphragm plate of the present invention has a light shielding wall 6 that allows light to pass along the optical axis in an opening 61 of the diaphragm plate 6 surrounded by a crosspiece 63.
2, the thickness dl of the aperture plate 6 can be made thin and the crosspiece 63dt can be made small.

Once the configuration of the lens 4a of the plate lens 4 is determined, the critical incident angle of the aforementioned single- and double-reflection ghost-like stray light is determined by simulation such as ray tracing. Based on this angle, the thickness d of the diaphragm plate 6 is set to a predetermined thickness, and the distance 1 between the light shielding walls 62 sufficient to block the ghost-like stray light at the opening 61 of the diaphragm plate 6 is determined.

The planar shape of the light shielding wall 62 formed in the opening 61 of the aperture plate 6 may be square, round, hexagonal, etc., as shown in FIGS. It is desirable that the shape follows the aperture shape of the aperture plate.

The aperture plate 6 can be made of metal, synthetic resin, paper, etc., and can be made by etching, pressing, injection molding, UV curing, or other processing methods depending on the material selected.

When the aperture plate 6 of the present invention is provided between the plate lens 4 and the roof mirror array 5, as shown in FIG. The incident light of is shown as ■, and these ghost-like stray lights are
(2) shows a state where the light is blocked by the light blocking wall 62.

〔effect〕

With the configuration of the present invention, ghost-like stray light that is reflected once and reflected twice can be blocked by the light-blocking wall of the thin diaphragm plate,
The distance between the plate lens and the roof mirror array is brought closer, reducing light attenuation, increasing light utilization efficiency, producing bright 1x imaging, and the advantage of being able to downsize the 1x imaging element. It also has

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of the diaphragm plate of the present invention, Fig. 2 (<) (11) (A) is a plan view showing the shapes of various light shielding walls at the opening of the diaphragm plate of the present invention, and Fig. 3 is a diaphragm plate of the present invention. A schematic perspective view of a 1-magnification imaging element to which the diaphragm plate of the invention is applied, FIG. 4 is a sectional view of the optical system of the 1-magnification imaging element, and FIG. 5 is a schematic diagram showing prevention of stray light by the diaphragm plate of the invention. , Fig. 6 <4> (El) is a plan view and cross-sectional view of a conventional diaphragm plate, Fig. 7 is a schematic diagram illustrating ghost-like stray light reflected on two sides, and Fig. 8 is a schematic diagram illustrating ghost-like stray light reflected once. It is a diagram. l... Right angle mirror, 4... Plate lens, 5... Roof mirror array, 6... Diaphragm plate, 61... Opening, 62... Light shielding wall. 1st ■ (self (b) (c) 2nd @

Claims (1)

[Claims] a right-angle mirror that separates an object-side optical path and an image-side optical path; a plate-shaped lens that faces the right-angle mirror and has a plurality of lenses;
In a 1-magnification imaging element comprising a roof mirror array arranged corresponding to each lens of the plate lens, and an aperture plate provided between the plate lens and the roof mirror array, each of the aperture plates A diaphragm plate in a 1-magnification imaging element, characterized in that a plurality of light-shielding walls are provided in an aperture in parallel with an optical axis, the thickness of the diaphragm plate is reduced, and stray light that affects imaging performance is removed.