JPS59189773A - Picture reading lens array - Google Patents

Abstract

PURPOSE:To obtain a picture reading lens array which can prevent sufficiently the penetration of an unnecessary light and is inexpensive and is easy to produce, by forming the lens array with lenses arranged at proper intervals and arranging light shielding materials between these lenses vertically to the optical axis of lenses. CONSTITUTION:In the lens array of this invention, lenses L are arranged at intervals of a length (l) into a face. This length (l) is a length between edges closest to each other of adjacent lenses and is determined properly by design of the lens array. Light shielding materials 2 are provided in regions between individual lenses of this lens array, namely, regions on the outside of optical paths of individual lenses to prevent the unnecessary light, which is made incident to lenses obliquely, from being incident to photoelectric sensors. Normally, light shielding plates or black paint layers are used as these light shielding materials. Light shielding plates 4 are provided between lenses and photoelectric sensors 5, which are arranged a desired length apart from each other, vertically to the optical axes of lenses to obtain a more sufficient effect. Light shielding plates 4 are provided in parts other than optical paths of individual lenses, and normally, 2-4 light shielding plates 4 are arranged in parallel at intervals of a proper length in the direction of the optical axis of each lens.

Description

[Detailed description of the invention] The present invention relates to an image reading lens array.

Conventionally, lens arrays for document image reading υ used in copying machines and facsimile machines are arranged in such a way that each lens is placed in close contact with each other. We needed a lens that was long along the optical axis direction.

That is, as shown in FIG. 1, the conventional lens array has a photoelectric sensor "1 + J" corresponding to each lens L1 + "t".
is placed, for example, the light image of B of document L is placed on lens L,
The light passes through and is received by the photoelectric sensor S1. In this case, L.

6. Light transmitted from other lenses. For example, when image A passes through lens L and enters 81, Sl
In this case, a clear image B in which image A overlaps image B cannot be obtained. Therefore, a light shielding wall 6 is required to shield unnecessary light incident obliquely.

In conventional lens arrays, lenses Ll.

Since L, ------- are arranged closely, if the light shielding wall is not placed in most of the optical axis direction of the lens,
Since it is not possible to completely prevent light obliquely entering from the direction of the adjacent lens, the objective cannot be achieved. for example,
When the diameter of the lens L is 1 m, the light shielding wall 6 has a diameter of 0.
It was necessary to arrange it in the shape of a tunnel with a length of 8 to 0.9 kaku and a length of 5 to 20 kan. Such a cylindrical light shielding wall is complicated and expensive to manufacture.

The present invention solves the drawbacks of conventional image reading lens arrays, and consists of a lens array consisting of lenses arranged at appropriate intervals, and a light shielding layer between these lenses perpendicular to the lens optical axis. It is characterized by being placed in.

Next, embodiments of the present invention will be specifically described with reference to the drawings.

In the lens array according to the present invention, as shown in FIG. 2, lenses L are arranged in a plane at intervals of t. Here, the distance t between the lenses is roughly the closest distance between adjacent lenses, and is determined as appropriate depending on the design of the lens array.
Ru. The present invention provides a light shielding body 2 in the range between each lens of an optical system using such a lens array, that is, in the range outside the optical path of each lens, so that unnecessary light incident on the lens obliquely enters the photoelectric sensor. Try to prevent this from happening.

This light shielding body 2 is usually a light shielding plate or a black paint layer. When using a light shielding plate, it is desirable to provide it close to the lens array in order to block unnecessary light that enters the lens from an oblique direction as much as possible. Furthermore, in order to effectively achieve the object of the present invention, the light shielding body should be provided in the entire area between the lenses.

FIGS. 3 and 4 show lens arrays according to other improved embodiments of the present invention. FIG. 3 shows that by providing a light shielding plate 4 perpendicular to the optical axis of the lenses between the lenses arranged at a desired interval and the photoelectric sensor 5, a sufficient effect can be obtained. This is what I did. The light shielding plate 4 is installed in a portion other than the optical path of each lens. The number is not particularly limited, but usually 2 to 4 are arranged in parallel at appropriate intervals in the optical axis direction of the lens. When a plurality of light shielding plates 4 are provided in this way, in order to completely block unnecessary light entering the light-1 sensor 5, a range other than the optical path of each lens is blocked in a direction perpendicular to its optical axis. In addition, it is desirable to change the light-shielding area of the light-shielding plate 4 along the optical axis of the lens. That is, the closer the sensor is to the photoelectric sensor 5, the larger the light blocking area becomes.

A light shielding plate suitable for such a purpose can be conveniently obtained by punching a thin plate according to the diameter of the lenses of the lens array 3 and the spacing between the lenses. For example, in the case of a lens diameter of about III+1, holes with a diameter of about 0.5 to 0.9 scale are formed in a light-shielding thin plate with a thickness of about 0.1 to 0.5 fins. In this case, the above-mentioned light-shielding area can be adjusted by keeping the hole pattern the same and changing only the diameter.

Furthermore, when carrying out the present invention, the space between the lens and the light-shielding plate or between the light-shielding plates is usually an air layer, but it may also be filled with a transparent medium such as acrylic resin, and the light-shielding plate is embedded in the transparent medium. good.

FIG. 4 shows another different embodiment of the invention.

By combining the two lens arrays 3 and 3', the image read by the photoelectric sensor 5 can be continuously read in the same erect state as the original.

Each lens array has a transparent intermediate layer between its front and back surfaces, and in this embodiment, a light-shielding coating layer and a light-shielding plate are provided on the document-side lens array 3 of the lens array.

However, if necessary, a light-shielding coating layer or a light-shielding plate may be similarly provided on the lens array on the photoelectric sensor side or between these two lens arrays.

As explained above, in the present invention, an image transmission lens array is formed of lenses arranged at appropriate intervals, and a light-shielding body such as a light-shielding coating or a light-shielding plate is arranged between these lenses perpendicularly to the optical axis of the lens. This prevents unnecessary light incident diagonally from entering the photoelectric sensor. Furthermore, by providing a plurality of light shielding bodies spaced apart in the optical axis direction of the lens, it is possible to sufficiently prevent the unnecessary light from entering, so that images can be read clearly.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional explanatory diagram of a conventional lens array, Fig. 2 is a cross-sectional explanatory diagram of the most general lens array according to the present invention, and Figs. 3 and 4 show other embodiments of the present invention. Cross-sectional explanatory diagram. In the figure 2, 1 is a document, 2 is a light shield, 3 is a lens array, and 5 is a photoelectric sensor. 71 river 72) 3)'・H;r4 river/ ■

Claims (1)

[Scope of Claims] (1) In a lens array for image transmission equipped with a photoelectric sensor on the opposite surface to the reading p side, the lens array is composed of lenses arranged in a plane at appropriate intervals. An image reading lens array in which a light shield for preventing unnecessary light from entering the photoelectric sensor is arranged between each lens perpendicularly to the lens optical axis. (2) The image reading lens array according to claim 1, wherein the light shielding member is a light shielding plate with a lens portion cut out. (8) Claim 1 in which the light shielding body is a black coating film
Image reading wrinkles/squeezes as described in section.