JPH0626417B2 - Original scanning optical device - Google Patents

Description

The present invention relates to an original reading optical device suitable for use in, for example, a facsimile or the like.

[Conventional technology]

Regarding various optical systems of the conventional facsimile, pl
us E. No. 50 (January 1984) in the article entitled "Application of Micro-Optics to Facsimile" by Komiya. A conventional example of the reading optical system therein is shown in FIG. In FIG. 2, reference numeral 11 denotes an original, which is illuminated by a light source 12 to read the original 11.
Through the lens 13, the reading sensor 14 photoelectrically converts the content of the document 11 to read it.

In this conventional reading optical system, as the light source 12 for illumination, for example, a fluorescent lamp or an LED light emitting element is used, and these light sources 12 are directly used for illumination. However, there is a point to be improved in that the illumination efficiency to the image is poor, the characters or images read from the document 11 become light and shade, and the image lacks in sharpness.

In consideration of the above, conventionally, for example, JP-A-57-688 has been used.
As disclosed in Japanese Patent Publication No. 01-001, as a method of illuminating a reading line of a document, a plate-shaped light guide (optical waveguide) is used to configure an illuminating optical waveguide, and the illuminating optical waveguide has a light incident end. It has been proposed to provide a light source with a reflecting mirror and arrange the illumination optical waveguide at both sides of a reading optical system lens at an angle.

[Problems to be Solved by the Invention]

As described above, the optical waveguide for illumination arranged on both sides of the reading optical system lens guides the light to the original without the light from the light source, so the illumination efficiency is improved while the light source is downsized, and the sharpness of image reading is improved. However, there were the following points to be improved.

That is, when the illumination optical waveguides are arranged on both sides of the reading optical system, each illumination optical waveguide is set at a predetermined angle (so that the light emitted from the illumination optical waveguide is reflected on the reading optical system lens side on the original. Since it is arranged at a set angle, for example, 45 °, there is a problem that the ratio of the position space of the illumination optical waveguide and the reading optical system becomes large.
In addition, the work of attaching these optical system parts has been time-consuming.

The present invention has been made in view of the above points, and an object thereof is to improve the efficiency of illuminating a document to improve the clarity of a read image, and further, to reduce the size of the apparatus and simplify the work of mounting parts. To provide a device.

[Means for Solving the Problems]

The features of the present invention will be described with reference to the reference numerals used in FIG. 1 for easy understanding.

The present invention illuminates a document using light from the light source 4,
A photoelectric conversion type reading sensor 6 detects the reflected light from the document.
In the original reading optical device of the type that receives light by means of a plate, the plate-shaped illumination optical waveguide 3 for guiding the light from the light source 4 to the original reading line position 9 and the reading sensor 6 for the reflected light at the original reading line position 9 are used. And a plate-shaped reading optical waveguide 2 for guiding the reading optical waveguide 2 and the reading and illuminating optical waveguides 2 and 3 sandwiching the reading optical waveguide 2 and arranging the illuminating optical waveguides 3 on both sides thereof. And a length 1 from the light incident end face 3-1 to the light emitting end face 3-2 of the illumination optical waveguide 3 and the light incident end face 2-1 to the light emitting end face 2 of the reading optical waveguide 2. The length 2 up to -2 is 1 << 2, and the end portion 3A of the illumination optical waveguide 3 on the light incident side has a thickness D that spreads toward the opposite side 3a "of the optical waveguide overlapping surface 3a '. Shape and increase The light incident end face 3-1 of the illumination optical waveguide 3 is inclined upward from the overlapping face 3a 'toward the opposite face 3a ", and the inclined light incident end face 3-1 is provided with the light reflector 5. It is characterized in that a light source 4 for line illumination is provided.

[Action]

The plate-shaped reading optical waveguide 2 and the plate-shaped illuminating optical waveguides 3 arranged on both sides thereof have a sandwich-like overlapping structure, and in addition, the light incident end face 3-1 of the illuminating optical waveguide 3 is added.
From the light emitting end face 3-2 to the light emitting end face 3-2 and the light incident end face 2-1 of the reading optical waveguide 2 from the light emitting end face (2-
By setting the length 2 up to 2) to 1 << 2, the light source 4
Also, the illumination optical waveguide 3 including the light reflector 5 and the reading optical waveguide 2 are compactly integrated into a single assembly, and as a result, the entire document reading optical system (including the illumination optical system) is simplified. The optical waveguide for illumination 3 and the optical waveguide for reading 2 can be made compact and can be attached to an installation place as a single assembly, and the work of attaching these optical components can be simplified. .

Even if the reading optical waveguide 2 and the illuminating optical waveguide 3 are superposed in a sandwich shape, the end 3A on the incident end face 3-1 side of each illuminating optical waveguide 3 has one side 3a ″ direction (optical waveguide 2, By increasing the thickness D in the diverging direction in the direction opposite to the overlapping surface 3a 'of 3), the installation area for the light source 4 at the incident end face 3-1 is sufficiently secured, and the light incident end face 3
-1 includes the overlapping surface 3a 'and the opposite surface 3a'.
Since the light source 4 with the light reflector 5 is provided so as to be inclined upward toward the "a" side, the light source 4 and the light reflector 5 can be installed without hitting the side surface of the reading optical waveguide 2, and as a result, As a whole, the illumination optical waveguide 3 including the light source 4 and the reflector 5 leans to the side surface of the reading optical waveguide 4, that is, a sandwich superposition structure is realized.

Further, since the light source 4 faces the inclined incident end surface 3-1 as described above, light from the light source 4 (including light reflected by the light reflector 5) reflects on the inner wall of the illumination optical waveguide 3. However, it is possible to efficiently illuminate the reading line position 9 of the document 1 at an appropriate angle, and the reflected light of the document reading line position 9 passes through the optical waveguide 2 and the reading sensor 2-.
Guided to 2. Therefore, the sharpness of the read image can be improved. In this case, since the two illumination optical waveguides 3 are used, the illumination can be increased.

〔Example〕

 An embodiment of the present invention will be described with reference to FIG.

FIG. 1 is a sectional perspective view of an original reading optical device according to an embodiment of the present invention.

In FIG. 1, 1 is a document, 2 is a reading optical waveguide,
3 is an optical waveguide for illumination.

The illumination optical waveguide 3 guides the light from the light source 4 to a predetermined reading line position 9 on the original 1, and the reading optical waveguide 2
The light reflected at the reading line position 9 of the original 1 is guided to the reading sensor 6, and these optical waveguides 2 and 3 are formed by a plate-shaped optical waveguide having a light incident end face and a light emitting end face in a linear shape. It In the reading optical waveguide 2, the portion indicated by reference numeral 2-1 is its incident end surface, the portion indicated by 2-2 is the emitting end surface, and in the illumination optical waveguide 3, the portion indicated by reference numeral 3-1 is its incident end surface. The portion indicated by 3-2 is the emission end face.

The plate-shaped optical waveguides 2 and 3 may be, for example, glass or plastic optical waveguides.
The refractive index of 3 may have a step shape or a refractive index distribution shape. Of these, the reading optical waveguide 2 is formed in a rectangular parallelepiped. The geometrical characteristics of the illumination optical waveguide 3 will be described later.

The illuminating optical waveguide 3 and the reading optical waveguide 2 have a sandwich structure in which the illuminating optical waveguide 3 is placed on both sides of the reading optical waveguide 2 and the illuminating optical waveguide 3 is overlapped.

From the light incident end face 3-1 of the illumination optical waveguide 3 to the light exit end face 3
-2 and the length 2 from the light incident end face 2-1 to the light emitting end face 2-2 of the reading optical waveguide 2 to 1 <<.
It is set as 2.

In addition, the shape of the illumination optical waveguide 3 is such that the incident end face 3-1.
The thickness D of the end portion 3A on the side increases toward the surface 3a 'opposite to the optical waveguide superposed surface 3a', and the light incident end surface 3-1 of the illumination optical waveguide 3 has a superposed surface 3a. There is an upward slope from ′ toward the opposite surface 3a ″ side.

A light source 4 for line illumination having a light reflector 5 is provided on the inclined incident end face 3-1.

As the light source 4, a plurality of LED light sources or a small fluorescent lamp can be used.

The light reflector 5 covers the periphery of the light source 4 to prevent light from escaping to the outside.

The reading sensor 6 is of a photoelectric conversion type and receives light emitted from the reading optical waveguide 2 and photoelectrically converts the content of the original 1 to read it.

The reading optical waveguide 2 and the illumination optical waveguide 3 are the original 1
Are arranged in a T-shape. Moreover, these optical components are housed in the housing 7 of the apparatus.

In the above configuration, the light emitted from the light source 4 enters the illumination optical waveguide 3 without escaping to the outside because the light source 4 is covered with the reflector 5. Moreover, even if the optical waveguides 2 and 3 have a sandwich structure, the illumination optical waveguide 3
Since the incident end face 3-1 of the light source 4 is made to face the light source 4 with an inclination in a predetermined direction, the light passing through the illumination optical waveguide 3 is directed to the inner wall of the optical waveguide 3 as shown by the broken line arrow in FIG. The original reading line position 9 close to the reading optical waveguide 2 while being reflected is efficiently illuminated at an appropriate angle so that the light and shade of the character or image of the original 1 is clearly displayed. Then, the reflected light that reflects the characters, figures, etc. of the original 1 passes through the reading optical waveguide 2, and the light is efficiently received by the reading sensor 6, and the original is read in this manner.

According to the present embodiment, as described above, by improving the illumination efficiency of the document reading line position, the sharpness of the document reading is enhanced, and further, the reading device is downsized, and the mounting work of its parts is simplified. Can be planned. The mechanism for improving the illumination efficiency, downsizing, and simplification of component mounting work has been described in detail in the section of the operation of the invention, and therefore the description thereof is omitted here. In addition, according to the present invention, the entire document reading optical system (including the illumination optical system) is downsized to rationalize the installation space, and for example, the illumination optical waveguide 3 and the light reflector 5 are provided close to each other. The other components 8 and the like can be installed with a sufficient margin, and the restriction on the space can be relaxed.

〔The invention's effect〕

As described above, according to the present invention, it is possible to improve the efficiency of illuminating a document to improve the sharpness of a read image, and further, to reduce the size of the apparatus of the related art and to simplify the work of attaching parts. it can.

[Brief description of drawings]

FIG. 1 is a sectional perspective view of a document reading apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of a conventional reading optical system. 1 ... manuscript, 2 ... reading optical waveguide, 3 ... illumination optical waveguide, 4 ... light source, 5 ... light reflector, 6 ... reading sensor, 7 ... device housing.

Claims (1)

[Claims] 1. An original reading optical device of a system in which an original is illuminated with light from a light source (4) and the reflected light from the original is received by a photoelectric conversion type reading sensor (6). A plate-shaped optical waveguide for illumination (3) that guides the light from (4) to the reading line position (9) of the document, and a plate that guides the reflected light from the reading line position (9) of the document to the reading sensor (6). Reading optical waveguide (2), and these reading and illuminating optical waveguides (2),
(3) is a sandwich-shaped overlapping structure in which the optical waveguide for reading (2) is sandwiched and the optical waveguide for illumination (3) is arranged on both sides thereof, and the light incident end face (3) of the optical waveguide for illumination (3) is formed. -1)
To the light emitting end surface (3-2), and the length l2 from the light incident end surface (2-1) to the light emitting end surface (2-2) of the reading optical waveguide (2) is l1 << l2, and the end portion (3A) on the light incident side of the illumination optical waveguide (3) is
The thickness D of the light guide end face (3-1) of the illuminating optical waveguide (3) is overlapped with the light guide end face (3-1) of the illuminating optical waveguide (3). Inclined from the mating surface (3a ′) to the opposite surface (3a ″), and the inclined light incident end surface (3-
Light source (4) for line illumination with light reflector (5) in 1)
An optical device for reading an original, characterized by comprising: