JPS5857089B2 - Suritsutoshiyoumeisouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a slit illumination device that illuminates an object to be illuminated in the form of a relatively narrow slit.

In slit exposure type electronic copying machines, facsimile reading devices, etc., it is necessary to illuminate the original, which is the object to be illuminated, in the form of a relatively narrow slit. There are many cases where it becomes impossible to arrange the illumination light source near the illuminated part to be illuminated.

In such a case, a method that can effectively utilize the light amount of the tube-shaped light source lamp is to use an elliptical reflector.

As is well known, an elliptical reflecting mirror is a reflecting mirror whose cross-sectional shape in a cross section perpendicular to its length direction is uniform in the length direction and forms an elliptical arc, and its concave portion serves as a reflecting surface. The light source lamp is provided parallel to the tube-shaped light source lamp.

Such an elliptical reflecting mirror is formed so that the distance between the two focal points of the ellipse that characterizes its reflecting surface is approximately equal to the distance between the central axis of the light source lamp and the illuminated part, and If one focal point (hereinafter referred to as the focal point of the elliptical reflector) is approximately aligned with the central axis of the light source lamp, and the other focal point of the elliptical reflector is placed on the area to be illuminated, the light from the light source lamp will be reflected. Therefore, light can be effectively focused on the illuminated portion.

The larger the reflection area of the elliptical reflector, the better the light collection efficiency.

However, when the distance from the light source lamp to the illuminated area increases, the elliptical reflector itself has to become larger in order to supply a sufficient amount of light to the illuminated area.
This causes difficulties in device design.

In this case, as a method to increase the area of the reflecting surface and reduce the volume occupied by the elliptical reflector, the eccentricity of the ellipse (hereinafter referred to as the eccentricity of the elliptical reflector), which characterizes the reflecting surface of the elliptical reflector, is There is a way to make the ellipse flat by increasing the elliptical reflector, but since a tube-shaped light source lamp must be placed at one focal point of the elliptical reflector, the flatness of the elliptical reflector itself is There is a limit.

In view of the above, an object of the present invention is to provide a light source lamp with:
It is an object of the present invention to provide a slit illumination device that can most effectively focus light from a light source lamp on a portion to be illuminated depending on its position relative to the portion to be illuminated.

Hereinafter, the present invention will be described by way of examples with reference to the drawings.

FIG. 1 shows an example of a slit illumination device embodying the present invention.

That is, the slit illumination device is for illuminating a document in an exposure optical system of an electronic copying machine.

In FIG. 1, 0 is the document, 1 is the document mounting glass, 2 is the imaging optical system, 3 is the photoreceptor, 4 is the light source lamp, 5 is the first elliptical reflector, and 6 is the It shows a second elliptical reflecting mirror.

The light source lamp 4, the first elliptical reflector 5, and the second elliptical reflector 6 constitute a slit illumination device according to the present invention, which illuminates the illuminated area a in a slit shape.

As shown in FIG. 2, the imaging optical system 2 includes a large number of convergent light transmitting bodies 2-1.2 having the same shape and having the shape of long thin rods cut to a length that can form an erect, same-magnification image. -2,・・・・・・・・・
・j2 i? . . . in one direction perpendicular to the length direction, in parallel and close to each other, in the densest arrangement, and by aligning both ends in the length direction, individual convergence is achieved. The resin frame 2 is arranged so that the collective surface of the end surfaces of the optical transmission body 2-1 forms an elongated slit-shaped end surface in the alignment direction.
It is integrated with a.

This imaging optical system 2 is installed at a position exactly midway between the document surface and the light transmitting body 3, but since the installation conditions are fixed, there is no flexibility in the arrangement of other machines, The slit illumination device according to the present invention is effective as an illumination device when the image optical system 2 is used.

The exposure of the photoreceptor in the electronic copying machine is performed by illuminating the illuminated area a with the slit illumination device, while illuminating the original 0,
The document holding glass 1 on which this is placed is conveyed in the direction of the arrow, and at the same time, the drum-shaped photoreceptor 3 is transported so that the speed of its circumferential surface is equal to the conveyance speed of the document 0. Rotate in the direction of the arrow at angular velocity.

Then, due to the lens action of the individual converging light transmitters 2-1 of the imaging optical system 20, a real image of the illuminated portion of the original 0 is formed on the photoreceptor 3, and as the original 0 is transported, , manuscript 0
An electrostatic latent image corresponding to is formed on the photoreceptor 3.

As described above, the slit illumination device is composed of the light source lamp 4, the first elliptical reflector 5, and the second elliptical reflector 6.

The light source lamp 4 has a tubular shape, and a fluorescent lamp is used in this example, but it goes without saying that a well-known halogen lamp or the like may be used depending on the case.

The first elliptical reflecting mirror 5 is formed to surround the light source lamp 4, and the center axis of the light source lamp 4 is aligned with the first elliptical reflector 5.
is arranged so as to coincide with the first focal point P1 of the elliptical reflecting mirror 5.

Then, when the light source lamp 4 is made to emit light, the light from the light source lamp 4 is emitted as if the center axis of the light source lamp 4 were the light source, and the first elliptical reflecting mirror 50 The light reflected by the reflective surface is focused on the second focal point P2 of the first elliptical reflecting mirror 5, and becomes a second light source.

Now, the second elliptical reflector 6 has its long axis aligned with the long axis of the first elliptical reflector 5, and its negative focus coincides with the second focus P2. It is provided.

Therefore, the other focal point P3 of the second elliptical reflecting mirror 6 is on the same straight line as the first focal point P1 and the second focal point.

For the ideal case, to be more precise, the first
A straight line connecting the focal point P1 of
2, 3 in which the other focal point P3 is connected in the above length direction, respectively.
This means that the straight lines in a book lie on the same plane.

This plane will hereinafter be referred to as the principal plane.

Therefore, if the other focal point P3 of the second elliptical reflector 6 is located at the illuminated area a, the light from the second light source reflected on the reflective surface of the second elliptical reflector 60 can be is focused on the other focal point P3.

Furthermore, since the first focal point P1, the second focal point P2, and the other focal point P3 are on the same straight line, the illuminated area a receives light from the second light source that focuses on the other focal point P3, as described above. In addition to the reflected light, direct light from the light source lamp 4 and direct light from the second light source illuminate a slit shape parallel to the length direction of the imaging element 2, and the illuminated area a is A sufficient amount of light can be effectively supplied.

In this example, the second elliptical reflector 6 is integrally connected to the first elliptical reflector 5 at its opening, but it is not necessary to integrate the first and second elliptical reflectors. There's no need.

However, if they are integrated, alignment operations for focusing both elliptical mirrors during device assembly become unnecessary.

Further, in this example, the long axis and eccentricity of the second elliptical reflector 6 are made larger than those of the first elliptical reflector 5, but this is not necessarily the case. It doesn't have to be this way.

However, by doing so, the slit illumination device itself can be made more compact.

The acid first elliptical reflector 5 may be made small enough to accommodate the light source lamp 4, but if a fluorescent lamp is used as the light source lamp 4, the second focal point P2 is the same as the light source lamp 4. must be kept outside the jurisdiction of the government.

By the way, the intersection of the main plane and the first elliptical reflector, that is, the part that is in the shadow of the light source lamp when viewed from the illuminated area, has the function of condensing the light from the light source lamp to the second focal point. This is the part that does not have it.

Therefore, as in the embodiment shown in FIG. By making the surface portions separate, it becomes easier to form the first and second elliptical reflecting mirrors.

In particular, if the reflective surface portions facing each other across the main plane are made symmetrical, they can be formed using the same mold.

Also, by doing this, if, for example, the reflective surface becomes cloudy, each reflective surface can be easily exposed, making it very easy to clean the surface.

Particularly when the second elliptical reflecting mirror has a large eccentricity and is flat, it goes without saying that it is effective in the above-mentioned respect to separate the opposing reflecting surface portions.

Now, all of the light from the light source lamp 4 that is first reflected by the first elliptical reflector, that is, all of the light that has been reflected only once on the reflective surface of the first elliptical reflector, is immediately transferred to the second elliptical reflector. It is a part of the reflective surface of the first elliptical reflector that allows the primary reflected light to enter the reflective surface of the second elliptical reflector.

In the embodiment shown in FIG.
It has only a reflective surface that can effectively cause the next reflected light to enter the reflective surface of the second elliptical reflector 620.

That is, in this example, the connecting portion between the first elliptical reflector 52 and the second elliptical reflector 62 is notched, and direct light from the light source lamp 4 emitted through the notch is directed to the second elliptical reflector. An auxiliary reflecting plate 7 is provided for the purpose of effectively focusing light on the other focal point P3 of the reflecting mirror 62.

The auxiliary reflector 7 is an elliptical reflector, and its focal points are the first focus P1 of the first ellipse reflector 52 and the other focus P3 of the second ellipse reflector 62.

The first elliptical reflective mirror 52 and the second elliptical reflective mirror 62 may be separate bodies, or may be integrally formed, and the cutout portion may be formed in the shape of a slit.

FIG. 5 is similar to the embodiment shown in FIG. 4, in which the largest amount of the first reflected light is incident on the reflecting surface of the second elliptical reflecting mirror 620.

Since there is no possibility of confusion, the same reference numerals as in FIG. 4 have been used for machines having the same functions.

In this case as well, the first elliptical reflector 52 and the second elliptical reflector 62 may be integrated or separate.

In addition, as in the embodiment shown in FIG. An auxiliary elliptical reflecting mirror 71 with a small size may be provided.

The reference numeral 53 in FIG. 6 is, of course, the first elliptical reflecting mirror.

As described above, according to the present invention, it is possible to provide a slit lighting device that can effectively condense the light emitted by the light source lamp onto the illuminated area and supply a large amount of light to the illuminated area without increasing the amount of light emitted from the light source lamp. .

In addition, three or more elliptical reflectors should be arranged so that their long axes are on the same straight line, and adjacent elliptical reflectors share one focal point, and the elliptical reflector at one end A slit illumination device in which a light source lamp is arranged at a non-shared illumination point of the mirror can also be considered as a variant of the slit illumination device according to the invention.

[Brief explanation of drawings]

FIG. 1 is a side view showing one embodiment of the present invention, and FIG. 2 is a side view showing an embodiment of the present invention.
FIG. 1 is a perspective view showing the shape of an imaging element designated by reference numeral 2, FIG. 3 is a side sectional view showing another embodiment of the present invention, and FIG. 4 is a side sectional view showing another embodiment of the present invention. FIG. 5 is a side sectional view showing still another embodiment of the invention, and FIG. 6 is a side sectional view showing still another embodiment of the invention. 0... Original, a... Illuminated area, 4...
...Light source lamp, 5, 51, 52, 53...
・First elliptical reflector, 6.61, 62, 63...
-Second elliptical reflector, 7...Auxiliary reflector.

Claims (1)

[Scope of Claims] 1. A tubular light source lamp, and a second light source lamp, which is provided so as to surround the light source lamp with its central axis substantially coinciding with a first focal point, and has an opening in the vicinity of a second focal point. a second elliptical reflector with one focal point coincident with the second focal point, and the other focal point of the second elliptical reflector is set near the illuminated part. A device for illuminating the illuminated portion in a slit shape, wherein the first focal point, the second focal point, and the other focal point are arranged in a plane perpendicular to the length direction of the light source lamp, A slit illumination device characterized in that the slits are arranged substantially on the same straight line in this order. 2. The feature is that the long axis and eccentricity of the second elliptical reflector are made larger than the long axis and eccentricity of the first elliptical reflector without changing the distance between the illuminated part and the light source lamp. A slit illumination device according to claim 1. 3 At the opening of the first elliptical reflector, a straight line that integrally connects the second elliptical reflector to the first elliptical reflector and connects the first focal point, the second focal point, and the other focal point. 2. The slit illumination device according to claim 1, wherein the intersection portions of the first elliptical reflecting mirror and the first elliptical reflecting mirror are cut out to form separate reflecting surface portions that face each other across the straight line. 4 A second elliptical reflector is attached to the first ellipse reflector, and
are integrally connected at the opening of the elliptical reflector, and the first
, the second focus, the straight line connecting the other focus, and the first
In the second elliptical reflector, the intersection part is cut out to separate the reflecting surface parts facing each other via the straight line, and the distance from the light source lamp to the illuminated part remains unchanged. 2. The slit illumination device according to claim 1, wherein the long axis and eccentricity are larger than the long axis and eccentricity of the first elliptical reflecting mirror. 5 Instead of a part of the reflecting surface of the second elliptical reflector, a third elliptical reflector that is in the same shape as the second elliptical reflector and whose eccentricity is smaller than the second elliptical reflector is used as an auxiliary reflector. A slit illumination device according to claim 1, characterized in that it is provided with a slit illumination device. 6 A part of the reflective surface of the first elliptical reflector is cut out so that the primary reflected light does not directly enter the reflective surface of the second elliptical reflector, and the light source lamp is emitted from the cut out part. 2. The slit illumination device according to claim 1, wherein an elliptical reflecting mirror having a first focal point and the other focal point is provided as an auxiliary reflecting plate at a position capable of reflecting the direct light of the slit lighting device.