JPH03182165A - Optical transmission element and optical transmitter using the element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an optical transmission element and an optical transmission device using the same. It is suitable for image reading devices such as copying machines and facsimile machines that guide light onto a line sensor surface made of a solid-state image sensor (CCO) and read an image on the document surface.

(Prior Art) Conventionally, in image reading devices such as facsimile machines, an illumination system illuminates an image on a document surface in a line shape.

The light beam reflected from the document surface is guided onto the line sensor surface in which a plurality of elements are arranged in one dimension (main scanning direction) using a light guiding means, and the output signal from the in-sensor is used to capture the image. is being read in one-dimensional direction. The entire image on the surface of the document is read by moving the document in the sub-scanning direction.

At this time, the light guiding means that guides (images) the reflected light flux based on the image on the document surface onto the line sensor surface has conventionally been made of a cylindrical glass column with a refractive index distribution formed in the radial direction using an ion exchange method. An optical transmission device was used in which multiple optical transmission trees were arranged in an array.

(Problems to be Solved by the Invention) In the optical transmission 9iWt in the conventional double-image reading device d, each of the plurality of optical transmission elements constituting it each scans an image within a certain range on the document surface in a line. Formed on the sensor surface, the line formed by the plurality of optical transmission elements is shifted little by little from the line sensor surface -E to the east to form one f4.

If the optical axes of these 51 individual optical transmission lines J'/- are shifted, the images on the line sensor surface will not align and will shift from each other, resulting in a decrease in WIAllK and a decrease in the accuracy of reading one image. was there. Conventional optical transmission devices have adopted a manufacturing process in which a plurality of optical transmission elements are arranged with their optical axes precisely aligned and then fixed. For this reason, there was a problem in that the manufacturing process became complicated and difficult.

The present invention facilitates the arrangement process when arranging a plurality of optical transmission elements in a predetermined relationship by appropriately setting the external shape and internal optical properties of the optical transmission elements, and The object of the present invention is to provide an optical transmission element that can guide a light beam with high intensity onto a line sensor surface such as a CCD arranged in a one-dimensional direction, and an optical transmission apparatus using the same.

c) Means for Solving Problems) The optical transmission element of the present invention has an entrance surface and an exit surface in the long plane direction of a rectangular parallelepiped, and transmits the light beam incident from the entrance surface along the long plane direction. In the optical transmission element, the refractive index of the medium in one direction perpendicular to the longitudinal direction of the optical transmission element is formed to have a refractive index distribution, and a reflection means is provided for reflecting an incident light beam on a copper surface perpendicular to the one direction. It is characterized by what it did.

In addition, the optical transmission ``AM'' according to the present invention includes a plurality of optical transmission elements, the directions in which the refractive index distributions of the optical transmission elements are formed are the same, and the optical transmission elements are provided with reflection means. 1Nlti are arranged in 7 lays so as to be in contact with each other.

(Embodiment) FIG. 1(A) is a perspective view of a main part of an embodiment when the optical transmission device according to the present invention is applied to an image reading device, and FIG. 1(B)
is homeland A in Figure (A).

In the figure, numeral 1 is a document, which is moving at a constant speed in the sub-scanning direction indicated by arrow 1a. Reference numeral 3 denotes an illumination system, which is comprised of a light source (for example, a fluorescent lamp) having a light emitting surface that illuminates the image on the surface of the document in a line in the main scanning direction indicated by arrow 1b.

2 is an optical transmission device, which includes a plurality of optical transmission elements 2a, 2b, .
What are you doing? The optical transmission element has a rectangular parallelepiped shape, and has an input 11ii21 and an output thi22 in the longitudinal direction (arrow 23), and II incident from the input surface 21.
A beam of light based on both the X, L and physical images is transmitted in the longitudinal direction.

Taking one optical transmission element 2a as an example, the material inside the element changes as it moves away from the center O as shown in FIG. It has a refractive index distribution in which the refractive index n, gradually decreases. As shown in FIG. 2(n), the light beam incident from the point PI of the incident fjJ21 is guided along the optical path 24 to the point P2 of the exit surface 22.

Further, as shown in FIG. 2(C), the copper surface 25 of the optical transmission element 2a in a direction perpendicular to the above-mentioned one direction (main scanning direction 1b) is provided with a reflecting means to reflect the incident light beam.

As shown in FIG. 2(D), the reflecting means in this embodiment is made of a material having a refractive index n1 lower than the refractive index n of the medium of the optical transmission element that totally reflects the reflective material or the incident light flux. There is.

Then, the plurality of optical transmission elements 2a, 2b, etc. are arranged so that the directions in which the refractive index distribution is formed (the sub-scanning direction) face the same direction, and the side surfaces 25 of the optical transmission elements on which the reflection means are applied are in contact with each other. They are arranged in an array in the main scanning direction.

This constitutes an optical transmission device W12.

4 is a line sensor, which is constructed by arranging a plurality of elements in an array in the main scanning direction.

Reference numeral 5 denotes a document guide, which allows the document l to move smoothly.

In this embodiment, the optical transmission device W12 is configured so that the width C of one optical transmission element is the reciprocal 1/n of the number n of image reading bells, and a plurality of such optical transmission elements are installed in each of the line sensors 4. They are arranged and configured in correspondence with the elements.

In this embodiment, the illumination system 3 illuminates the R-1, and a light beam based on the image on the first surface of the document is guided onto the line sensor 4 through the optical transmission device 2.

At this time, out of the light flux from the image on the first side of the original, Fig. 2 (A
), a refractive index distribution is formed in the sub-scanning direction of the optical transmission element, so the light beam incident from the entrance surface 21 is converged and exits from the exit surface 22, as shown in FIG. 2(B). do.

On the other hand, since a reflecting means is provided on the side surface 25 in the main scanning direction, the light beam incident from the incident surface 21 is repeatedly reflected by the reflecting means on the side surface 25 as shown in FIG. light is guided.

In this way, the light beam based on the image on the first side of the original is read and guided onto the line sensor 4 according to the number of bells, and the line sensor 4 reads the shading of the image on the first side of the original.

Next, the characteristics of the optical transmission element 2a according to this embodiment will be explained.

FIG. 4 is a perspective view of essential parts of the optical transmission element 2a according to this embodiment.

In the optical transmission element 2a of this embodiment, a reflecting means 42 is provided on the side surface 25 in the longitudinal direction indicated by the arrow 23. The reflecting means 42 is made of a material having a refractive index n that is smaller than the refractive index n of the material of the inside 41 of the optical transmission element, and the reflecting means 42 totally reflects the incident light beam in the same way as an optical fiber.

That is, as shown in FIG. 3, the optical fiber has a cylindrical structure in which the central region 31 and the peripheral region 32 are made of materials with different refractive indexes. Refractive index n of 32.

is small (n・〉n,), and the central region 3
! The light flux incident on the central region 31 is repeatedly totally reflected at the interface with the peripheral region 32 and passes through the central region 31 .

Utilizing the same optical principle, the optical transmission element of this embodiment uses a material with a high refractive index for the center portion 41 as shown in FIG. The reflecting means 42 is made of a material with a low index.

As a result, as shown in FIG. 5(A), the optical transmission element f-2a
The light beam incident on the central region 41 is repeatedly totally reflected at the interface with the reflecting means 42 and transmitted.

On the other hand, at this time, in the other plane of the optical transmission element 2a on which the reflection means 42 is not provided, when the inside is a homogeneous medium, as shown in FIG.
), the luminous flux diverges.

Therefore, in this embodiment, the gs double surfaces 5 of a plurality of optical transmission elements are bonded to each other, cut in a direction perpendicular to the bonded surfaces, and made into a plate shape. A refractive index distribution is formed.

As a result, as shown in FIG.
The luminous flux incident on 5! is shown in Figure 5 (B) G2. The light is converged as shown by the light path 24 without being lost, and is guided to a point P2 on the exit surface 62.

In this embodiment, by appropriately setting the length of the optical transmission element in the longitudinal direction, the light beam incident from the incident surface 61 is condensed onto the line sensor surface. As a result, the image on one side of the original is read by the line sensor.

In this embodiment, an optical transmission device using an optical transmission element having the following configuration can be applied.

(a) Both surfaces (111 sides) of the thin light transmitting member are coated with a material having a lower refractive index by a method such as dipping to form a reflecting means. And a light-transmitting member like this? 11
1 After bonding the 111 surfaces together, cut it into a plate shape in a direction perpendicular to the bonded surfaces, and form a refractive index distribution in the direction perpendicular to the bonded surfaces (sub-scanning direction) using an ion exchange method. do. Then, it is cut to an appropriate length to construct an optical transmission device.

(b) A reflecting member is formed by coating both surfaces (g!4 surfaces) of a thin light-transmitting member with a reflecting member. After attaching a plurality of these light transmitting members to each other with their side surfaces, they are cut in a direction perpendicular to the bonded surfaces, and a refractive index distribution is formed in the direction perpendicular to the bonded surfaces (GL scanning direction) using an ion exchange method. do. Then, it is cut to an appropriate length to construct an optical transmission device.

(c) A thin, light-transmitting member is subjected to short-time ion exchange so that only the surface has a smaller refractive index than the inside. At this time, reflecting means is formed on the side surface. After bonding the side surfaces of a plurality of light transmitting members formed in this way to each other, cutting them in a direction perpendicular to the bonded surfaces to form a plate shape,
A refractive index distribution is formed in the direction C (sub-scanning direction) perpendicular to the bonding surface by an ion exchange method. Then, it is cut to an appropriate length to construct an optical transmission device.

Note that the optical transmission element according to the present invention is not limited to the rectangular parallelepiped shape described above, but may be similarly applicable to a cubic shape.

(Effects of the Invention) According to the present invention, in order to efficiently transmit light in the longitudinal direction of a rectangular parallelepiped, by using the optical transmission element configured as described above, it is possible to easily and highly accurately transmit light without going through a difficult manufacturing process. It is possible to use an optical transmission device in which multiple optical transmission elements are arranged in an array, which allows the image on the R area to be guided onto the line sensor surface with high precision, allowing for highly accurate image reading. Accordingly, it is possible to achieve an optical transmission element and an optical transmission apparatus using the optical transmission element.

[Brief explanation of drawings]

FIG. 1(A) shows the main part of an embodiment in which the optical transmission device according to the present invention is applied to an image reading device @Homeland, and FIG. 2(B) shows the main part of the first embodiment
A homeland in Figure (A), Figure 2 (A), (B), (C), (
D) is an explanatory diagram of an optical transmission device according to the present invention, FIG. 3 is an explanatory diagram of a conventional optical fiber, FIG. 4 is an explanatory diagram of an optical transmission device according to the present invention, and FIGS. 5 (A) and (B) 6 is an explanatory diagram of an optical path in one direction and a direction perpendicular to the one direction inside the optical transmission element according to the present invention, and FIG. 6 is an explanatory diagram of an optical path in one direction inside the optical transmission element according to the invention. In the figure, 1 is a document, 2 is an optical transmission device, and 2a, 2b. . . . is a light transmission element, 3 is an illumination system, 4 is a line sensor, and 42 is a reflecting means.

Claims (2)

[Claims] (1) In an optical transmission element that has an entrance surface and an exit surface in the longitudinal direction of a rectangular parallelepiped, and transmits the light beam incident from the entrance surface along the longitudinal direction, the beam is perpendicular to the longitudinal direction of the optical transmission element. 1. An optical transmission element, characterized in that the refractive index of a medium in one direction is formed to have a refractive index distribution, and a reflecting means is provided for reflecting an incident light beam from a side surface in a direction orthogonal to the one direction. (2) A plurality of the optical transmission elements are arranged in an array so that the direction in which the refractive index distribution of the optical transmission elements is formed is the same direction, and the side surfaces of the optical transmission elements on which the reflection means are applied are in contact with each other. An optical transmission device characterized in that: