JPS5844461A - Exposing device - Google Patents

Abstract

PURPOSE:To reduce the size and weight of an exposing device without occurrence of sinking by using a Fresnel lens at least for an intermediate plate lens among three plate lenses. CONSTITUTION:Plate lenses 1, 4 and 1 are stacked in order to form a layer, and are fitted in grooves 2a of a housing 2 made of aluminum, or zinc, etc. Some of the plate lenses 4 are Fresnel lenses 4a. Consequently, the lens is reduced in thickness and the extent of contraction is less, so a prescribed radius of curvature is obtained without a serious influence of sinking.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exposure apparatus used in a WV machine and the like, and more particularly to an exposure apparatus that can be easily made smaller and lighter.

A conventional exposure apparatus uses a plate-shaped lens in which a plurality of lenses are arranged in two rows in a staggered manner. However, the exposure device is required to be smaller and lighter in order to make the II photocopier smaller or to be able to move itself.

Therefore, by arranging multiple lenses in a row, the plate lens radius can be reduced and the exposure device can be made smaller and lighter. ! ! In Fig. 1, 1 and 1' in the figure are plate-shaped lenses molded from thermoplastic resin, and a plurality of lenses la, 1 m' are 1.
arranged in columns. This plate-shaped lens Kl, 1' corresponds to IIWk lenses la, 1 m above and below at a predetermined position.
' are fitted into the housing 2 with their optical axes aligned with each other, and are stacked at predetermined intervals with a honeycomb 3 interposed therebetween. Each plate lens 1. −． ．． 1′ plurality of lenses Ia,
When Im' is arranged in one row, lenses 1m and 1m' have a large refractive index in order to reduce unevenness in illuminance on the imaging plane. If the refractive index is increased, the corresponding 3
If the lenses la and la' have the same refractive index, they will be placed in the middle, and the refractive index of the lenses 1 & and ' will be weak, resulting in uneven illuminance. The lens 1a' provided has a particularly large refractive index and is approximately spherical.

Then, as shown in FIG. 2, the image of the original is focused on the second lens la I by the first lens 1&,
Second lens which is a field lens1. /, and the third lens 1a forms an erect, same-size image A' on the exposure surface.
imaged as.

When such a substantially spherical lens Ia' is molded from resin, it has a large wall thickness, so the amount of shrinkage is large and sink marks are likely to occur, and there is a risk that a predetermined radius of curvature cannot be obtained. Therefore, it is difficult to reduce the size and weight of the exposure apparatus, and there are limits to this.

The present invention has been made by focusing on such conventional problems, and it is possible to use a Fresnel lens in an exposure apparatus by using at least the middle plate lens among three plate lenses as Fresnel lenses. The purpose is to solve the above-mentioned problems by configuring this.

The present invention will be explained below based on the drawings. The same reference numerals are given to the same or equivalent members as in the prior art, and redundant explanation will be omitted. .

#! 3v! J ~ 3rd v! J~ is a diagram showing an embodiment of the present invention.

Explain the configuration. In Fig. 3, the upper plate-shaped lens 1
, plate lens 4, and plate lens 1, the plate lenses 1, 4.1 are fitted into grooves 2& of a housing 2 made of aluminum, zinc, etc., and stacked. The plate lens 4 among these is the 4th il! ! It is as shown in I. Each of the plurality of lenses of this plate-shaped lens 4 is a 7-lens lens 4a. 7 Renel lens 4a is
This is a known lens, which is formed from an arrangement of small lenses in the form of a ring, and the thickness of the lens is reduced.

Between the plate lenses 1 and 4.1, there are a plurality of light-shielding tube holes 3 &
A honeycomb 3 having a diameter of 100 mm is interposed between each honeycomb 3. The light-shielding tube holes 3 and 4 each have 1m of lenses whose optical axes are aligned with each other.
A predetermined optical path is formed between a and la to prevent flare from occurring.

As described above, the exposure device 5 is constituted by the plate lenses 1, 1, the plate lens 4 having a plurality of 7-lens lenses 4a, the housing 2, and the honeycomb 3. Therefore, the lenses corresponding to the upper and lower sides of the exposure device 5 are arranged as shown in FIG. 5 to form an erect image of the same size.

These plate lenses 1, 1.4 are manufactured by injection molding or compression molding using PMM (polymethyl methacrylate), PO (polycarbonate), P8 (polyethylene), or the like. At this time, 7 of the plate lens 4
Since the Lens lens 4& has a small amount of shrinkage, it has a predetermined radius of curvature without being affected by sink marks or the like.

To explain the functions of the corresponding lenses la and 1m and the Fresnel lens, as shown in FIG. It is refracted by Lennel lens-a, enters the third lens 1&, and is focused on the exposure surface by the 13th lens 1a as an erect, equal-magnification image A'.

In addition, in the above embodiment, the plate lens 4 having a Fresnel lens volume of 4 ml is replaced with another plate lens 1. i only in the middle of l! However, it can also be provided at other plate lenses 1.1.

As explained above, according to the present invention, the exposure apparatus is configured such that among the three plate lenses, the daughter plate lenses disposed at least in the middle are each 7 renel lenses. Almost no chips or the like occur, and therefore, a plate-shaped lens having a predetermined refractive index can be easily formed, and the exposure apparatus can be easily made smaller and lighter.

[Brief explanation of drawings]

FIG. 1 is a partially sectional perspective view showing a conventional exposure apparatus;
FIG. 2 is an explanatory diagram showing the shape of a lens used in a conventional exposure apparatus and the image formation state by the opposing lenses of each plate lens, and FIG. 3 is an explanatory diagram showing an exposure apparatus according to an embodiment of the present invention. FIG. 4 is a perspective view similar to FIG. 1; FIG. 4 is a perspective view showing a plate lens having a Fresnel lens according to an embodiment of the present invention;
FIG. 5 is an explanatory diagram similar to FIG. 2 according to an embodiment of the present invention. 1...Plate lens, 1&...lens, 4...Plate lens, 4&...7 Lenel lens, 5...Exposure position a. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] Three plate lenses each having a plurality of lenses are stacked at predetermined intervals in an exposure device, with the optical axes of the corresponding plurality of lenses aligned with each other. In addition, among the three plate lenses, at least the intermediate plate lens is each a 7-lens lens. Exposure equipment◎