JPS5827137A - Illuminating device - Google Patents

Abstract

PURPOSE:To eliminate the nonuniformity of the quantity of illuminating light in a longitudinal direction without losing the quantity of light by providing a member which diffuses the light from the filament of a lamp substantially only in the longitudinal direction of the lamp between said filament and an original. CONSTITUTION:A transparent body 10 having the rugged surface of which the top section is formed to the shape of plural arc lenses is provided between the filament of the lamp of an illuminating device which scans an original like slits by moving the lamp and the original and the original in such a way that the rugged section thereof faces the longitudinal direction (direction X) of the lamp. Since the body 10 has no optical structure in the scanning direction (direction Y), light is simply passed in said direction, while in the longitudinal direction, the light is refracted and widely diffused by the arc lens-like rugged surface. Thus the nonuniformity of the quantity of illuminating light in the longitudinal direction is eliminated and there is no loss of the quantity of light.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to an illumination device for scanning and illuminating a document in a slit shape for a copying machine or the like.

BACKGROUND OF THE INVENTION Conventionally, a light source based on the incandescence of a filament such as a halogen lamp has been used as an illumination light source for copying machines and the like.

For example, in a copying machine with a movable document table shown in FIG. 1, a lamp (1) as shown in FIG. 2 has a lamp (1) as shown in FIG. placed and surrounded by a reflective shade (3) with a filament) (
], a) The light of (1, 3) is directed to the document table (2), and the optical image of the document placed on the document table (2) is transmitted to an imaging element such as a convergent light transmitting array (4). through the photoreceptor (5
)”. Note that (6) is a color correction filter, and (7) is a reflection plate.

However, since such a lamp (1) directly utilizes the light emitted from multiple filaments (1, 3) (IQ...), the filaments are arranged in the longitudinal direction of the lamp (1) as shown in Figure 3. Non-uniformity in the amount of illumination light occurs at or below the interval.

In order to solve this problem, conventional methods have been to make the reflective surfaces of reflective shades and reflectors rough to diffuse the light. However, this method has the disadvantage that the light is also diffused in the scanning direction (Y direction), so the effective amount of light contributing to illumination is reduced.

Alternatively, there is a method of forming irregularities on the reflective shade of a lamp that diffusely reflects light only in the long direction.
This is proposed in Publication No. 21.

Reflector shades for lamps are usually made by extrusion molding of aluminum, but since the above-mentioned uneven portions must be formed in a direction perpendicular to the extrusion direction, they cannot be done simultaneously with extrusion molding. Therefore, the uneven portions must be processed afterward, but the subsequent processing is complicated and involves processing difficulties because the processing is performed on the inner surface of the reflective shade, which has a small curvature. That is, the method disclosed in Japanese Utility Model Application Publication No. 54-55821 is a very difficult method to process, and even if it could be realized, it would not be cost-effective.

Purpose/Summary The present invention has been made in view of the above two points, and an object thereof is to provide a lighting device that can solve the problem of non-uniformity in the amount of illumination light in the longitudinal direction without losing the amount of light with a simple configuration. shall be.

This object is achieved by interposing a member between the filament of the lamp and the document, which diffuses the light from the filament substantially only in the longitudinal direction.

Although the above-mentioned member may be a single member, it is more preferable to use it also as a filter provided between the lamp and the document, or as a lamp tube wall.

Diffusion in the longitudinal direction is performed by an uneven surface extending in the scanning direction, a one-dimensional diffraction grating that diffracts light in the longitudinal direction, or a plurality of reflective surfaces that reflect light only in the longitudinal direction.

Example Each embodiment will be described below with reference to the drawings.

The example shown in FIGS. 4A and 4B is a transparent body (10) having an uneven surface whose cross section is shaped like a plurality of circular arc lenses.

A color correction multilayer interference film (11) for matching the spectral sensitivity of the photoreceptor is formed on the back surface thereof.

For example, in FIG. 1, the color correction filter (6) is installed in place of the color correction filter (6) provided in front of the lamp (1).

5- When installed in this way, the transparent body (10) is aligned in the scanning direction (Y
In the longitudinal direction (X direction), the light simply passes through because it has no optical structure, while in the longitudinal direction (X direction), the light is refracted by the convex-concave surface in the shape of an arcuate lens and is widely diffused. In this case, the circular arc lenses do not have to be continuous as shown in the figure, but their size and pitch need to be appropriately determined according to the dimensions of the illumination device so as not to have any influence.

In this way, the light from the lamp is diffused only in the longitudinal direction, so that non-uniformity in the amount of illumination light in the longitudinal direction is eliminated and there is no loss in the amount of light.

The material of the transparent body (10) should be heat resistant since it will be exposed to the heat of the lamp, and glass is preferred.

Moreover, it may be manufactured by molding molten glass as a template glass, or by grinding and polishing a glass plate.

Furthermore, the cross-sectional shape may be parabolic or polygonal.

The example in Figure 5 is glass fiber (12) (12).
・Arrange them in a flat shape and heat and fuse them or
These are sheets (1, 3) in which one end surface of the 6-wire is bonded with a heat-resistant adhesive such as solder glass or the holding portion side.

The direction of the fiber is in the scanning direction (
(Y direction) between the lamp and the document.

This installation can be done either by itself or by installing it on a suitable glass plate. For example, the color correction filter (6
) J: is suitable. Also, each fiber may be attached to a glass plate or filter rather than to each other (J:G).

Like the transparent body (10), this sheet (13) also diffuses light only in the longitudinal direction of the lamp, thereby eliminating the non-uniformity of the illumination light [H].

In the lamp shown in FIG. 2, 1. O
A maximum and a minimum occurred at positions mm apart, and the difference in light intensity was 9%. In contrast, when we conducted an experiment in which a sheet formed of glass fiber with a diameter of 0.25 mm as shown in Figure 5 was placed exactly halfway between the lamp and the illumination surface, which were 5 jJm apart, the unevenness in the light intensity could not be discerned. It was possible to equalize the

An uneven surface that substantially diffuses light only in the longitudinal direction can also be obtained by subjecting a glass plate to a directional surface treatment.

That is, as shown in FIG. 6, a glass plate (14) that has been ground or sandblasted in one direction is placed between the lamp and the document with its processing direction aligned with the scanning direction (Y direction).

The example shown in FIG. 7 uses a one-dimensional diffraction grating plate (15). In this example as well, by making the grating direction coincide with the scanning direction (Y direction), the light can be diffused only in the longitudinal direction of the lamp by diffraction.

Although a light/dark grating may be used as the diffraction grating, a phase grating without loss of light quantity is preferable. The -dimensional phase grating was manufactured using a glass plate made of MgF, SiO, and MgF, taking heat resistance into account.

This is done by vacuum deposition using a grid (15a).

It goes without saying that the examples shown in FIGS. 6 and 7 can also be used as a color correction filter or a heat protection filter, similar to the above-mentioned examples.

In the example shown in FIG. 8, light is reflected substantially only in the longitudinal direction between lamp documents. That is, the frame body (1) has elongated reflecting plates (17) (17) in the direction perpendicular to the opening longitudinal direction.
・A reflector (18) with a large number of erected reflectors (17) (
17) An example of a lamp between originals is to arrange the color correction filter (6) in FIG. 1 so that the lamps are lined up in the longitudinal direction of the lamp. The reflector is preferably an aluminum plate or the like, and may be integrally molded with the frame.

In this embodiment, the light is reflected by the reflector (17) (17)...
It is reflected on both sides of the lamp and diffused in the longitudinal direction of the lamp, or it is not reflected in the scanning direction because there is no reflective surface.

In all of the embodiments described above, a member that diffuses light only in the longitudinal direction of the lamp is provided between the lamp originals, either alone or in combination with various filters, but it is also possible to apply a similar structure to the wall of the lamp tube. You can also do it.

For example, this can be accomplished by forming grooves in the circumferential direction of the lamp tube wall by pressing or grinding, and making the lamp tube wall itself an uneven surface.

For example, as shown in FIG. 9, wrapping the glass fiber (20) around the lamp tube wall (19) is achieved by fixing it with a heat-resistant adhesive such as solder glass or by heating. In this case, the glass fiber (20) is not strictly perpendicular to the longitudinal direction of the lamp, but for example, if the diameter of the lamp tube is 8.5 mm and the winding pitch is 0.5 tnm, the glass fiber (20) is not perpendicular to the longitudinal direction of the lamp. Since the inclination with respect to the orthogonal direction is 3.4°, the component in the direction perpendicular to the longitudinal direction is 5.9%, while the longitudinal component is 99.8%, so the light actually only flows in the longitudinal direction. It will be spread.

Note that the glass fiber (20) does not necessarily have to have a circular cross section, but can have any shape such as a semicircle, triangle, or square.

Further, the grooved surface treatment shown in FIG. 6 and the diffraction grating shown in FIG. 7 can also be achieved by forming them in the circumferential direction of the lamp tube wall.

The treatment for the lamp tube wall is closer to that of a filament than when placing a diffusion member between the lamp and the original.
It should be noted that the dimensional relationships must be made smaller to obtain the same effect.

Effects As described above, the present invention provides light from the filament between the filament 10- of the lamp and the original in an illumination device that scans the original in a slit shape by moving the lamp and the original relatively. Since the lamp is provided with a member that diffuses the light only in the longitudinal direction of the lamp, it is possible to solve the non-uniformity of the amount of illumination light in the longitudinal direction with a simple structure without losing 4 fi of light.

By solving the non-uniformity of the amount of illumination light with such a simple configuration, it becomes possible to bring the lamp closer to the illumination surface, making it possible to downsize the device and improve the light utilization rate.

Furthermore, in the past, the number of filaments was increased to compensate for unevenness in the amount of illumination on the lamp side, but in order to satisfy both this and the requirement for a low-power lamp, the filaments had to be made thinner, which required manufacturing and assembly. I was making it difficult. However, according to the present invention, it is possible to easily eliminate the non-uniformity of the illumination light amount, so that it is possible to realize a fip.

Further, by applying the structure of the present invention to various filters and the lamp tube wall itself, it is possible to eliminate non-uniformity in the amount of illumination light without increasing the number of parts.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an example of a scanning type copying machine, Fig. 2 is a perspective view showing a lamp, Fig. 3 is a diagram showing non-uniformity of the illumination light amount of the lamp, and Figs. It is a figure showing each example. 1... Lamp l a - Filament 2... Original table 3... Reflective shade 6... Color correction filter 10. Transparent body 11... Color correction multilayer interference film 12... Glass fiber 13... Sheet 14.・Glass plate 15 with one-way scratch surface treatment...-
Dimensional diffraction grating plate 15a...Grating 16...Frame
17...Reflector 18...Reflector X...Lamp longitudinal direction Y...For scanning direction Applicant Minolta Camera Co., Ltd. Figure 1 Figure 3

Claims (1)

[Claims] 1. In an illumination device that scans an original in a slit shape by moving the lamp and the original relatively, the light from the filament is transmitted substantially in the longitudinal direction of the lamp between the filament of the lamp and the original. A lighting device characterized by being provided with a member that diffuses light. 2. The lighting device according to claim 1, wherein the member has an uneven cross section in the longitudinal direction of the lamp. 3. The lighting device according to claim 1, wherein the member includes glass fibers arranged perpendicularly to the longitudinal direction of the lamp. The lighting device according to item 1. 5. The illumination device according to claim 1, wherein the member is a one-dimensional diffraction grating whose scanning direction is in the r-direction. 6. Claim 1, wherein the member is a plurality of reflecting plates arranged perpendicularly to the longitudinal direction of the lamp.
The lighting device described in Section 1. 7. The illumination device according to any one of claims 1 to 6, wherein the member is disposed between a lamp and a document. 8. The lighting device according to claim 7, wherein the member has a filter function. 9. The lighting device according to any one of claims 1 to 5, wherein the member is a lamp tube wall.