JPS63262959A - Image transfer element for image pickup device - Google Patents

Abstract

PURPOSE:To heighten the efficiency in use of a beam of light, by conducting the incident light and the reflected light of the beam of light by individual fiber by using a plastic fiber array in which a large number of plastic made step index type fibers are arranged. CONSTITUTION:The plastic fiber array in which a large number of plastic made step index type fibers are arranged is used for the transfer of the beam of light. The fiber 101 is a light conductive fiber which projects the beam of light on an original 105, and the fiber 102 is an image conductive fiber which conducts the reflected light from the original 105 to an image pickup element 103. Since the material of the fiber can be selected widely, the number of apertures of the fiber can be set freely, and it is possible to obtain a device with high efficiency in use of a light quantity without applying limitation on the arrangement of each element.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to an image transfer element of an imaging device in which the imaging element is equipped with a light source.

[Conventional technology]

Conventionally, an imaging device in which an imaging device is equipped with a same-magnification imaging device, an image transfer device, and a light source has generally taken the form as shown in the schematic cross-sectional views shown in FIGS. 4 and 5. Light source (405,
505) uses an LED array or fluorescent tube to display the manuscript (40
4,504) is reflected from the imaging device (402) using an imaging device (402) or a glass fiber array (502).
1,501) Make an image on top. Here, as an image sensor,
It was common to use a large array of gradient index lenses. There is also one using a glass fiber array in which a large number of 502 glass step index type fibers are arranged.

[Problem that the invention seeks to solve]

However, when a gradient index lens is used, the distance between the document surface and the image sensor surface is only about 15 mm, and the lens itself closes more than half of that distance, making the layout of the light source extremely difficult. This method has drawbacks such as inefficiency since the light source must be placed far away from the camera. Furthermore, if a glass fiber array in which a large number of glass step index type fibers are arranged is used, the distance between the document surface and the image sensor surface can be shortened. However, it is difficult to take full advantage of the brightness and thinness of glass fiber arrays because it requires some ingenuity in how the light enters and how it is blocked.

The present invention is intended to solve these problems, and its purpose is to fully utilize the brightness of the step index fiber to create an image transfer element used in a solid-state imaging device that is capable of moving between the document surface and the image sensor surface. It is in a place where we provide.

[Means for solving problems]

The apparatus of the present invention is characterized in that a plastic fiber array in which a large number of step index fibers made of glass are arranged is used as an image transfer element of an imaging device.

〔Example〕

FIG. 1 is a schematic cross-sectional view of an imaging device using an image transfer element according to an embodiment of the present invention. The 7-eyeper used is a step index type plastic fiber (fiber made from resin in general), and the diameter depends on the reading pitch of the image sensor, but in particular it is 1/4 of the pitch.
In the following, a 10μ lip position is usually used. Although only 5-6 rows are drawn in the horizontal direction, there are usually about 100 rows above. Well, 1
The fiber 01 irradiates light onto the original (105) (hereinafter referred to as a light guiding fiber), and the fiber 102 irradiates light onto the original (105), and the fiber 102 irradiates light onto the original (105).
3) (hereinafter referred to as image-guiding fibers), the light-guiding fibers and image-guiding fibers are arranged alternately in each row in Figure 1, but they may be arranged randomly to some extent.
This takes full advantage of the flexibility of plastic fiber. Also, the ratio between the total number of light guide fibers used and the total number of image guide fibers used can be determined depending on the amount of light and the characteristics of the image sensor.Of course, it is also important that the ratio does not deviate greatly locally, and A ratio change of 1.5 times or less in area is best read, depending on the pitch and fiber diameter, at least one light guide for each pixel size,
If each image-guiding fiber is not included, reading shims will occur, making it difficult to distinguish between black and white. For that reason, the pitch of 174
The diameters above are good.In addition, the ends of both the light guide fiber and the image guide 7 eyer are almost aligned on the document side. They are located in different directions, and can be used in any direction depending on the device design.

This is unique to plastic fiber.

Of course, the end faces are almost flush on the image sensor side, and FIG. 2 is a sectional view of another embodiment in which the end faces are in close contact with or close to the image sensor. After the light from the light source (202) passes through the fiber, two reflected lights are transmitted to the document (204) through the fiber and are imaged on the image sensor. The plastic fiber array has an angle of inclination (206) with the document surface and an angle of incidence (205) with the light source. These angles have a large effect on the efficiency of light usage and place restrictions on the arrangement of each element. In the case of glass fibers, a wide range of fiber materials can be selected, so the numerical aperture of the fiber can be freely selected from 0 to nearly 1, making the device highly efficient for use by seniors without placing restrictions on the arrangement of each element.

In addition, since it has a lower refractive index than glass, reflection (particularly total reflection) is less likely to occur, and furthermore, there is a high degree of freedom in design.Since it is a plastic material, it is easy to polish the end face at an angle.

FIG. 3 shows an embodiment in which a light emitting element and a plastic fiber 7 lay are integrated. A light-emitting element is mounted on a plastic fiber array (301) or a support (304) in the form of a step in the middle like the fiber 301, and light is guided to the document from the bent part of the fiber. The area sandwiched between the Glasstic 7 Eyeper array and the support becomes a protective area, so there is little need to fill this area with molding agent, but it is possible to fill the fiber cladding layer with a transparent material with a low refractive index. This will increase the efficiency of light use.

A large number of fibers in each figure are arranged in a plane direction as shown in FIG. 1, and are arranged in an area large enough to cover at least the light receiving part of a -dimensional or two-dimensional image sensor.

〔Effect of the invention〕

As described above, according to the present invention, when a glass 7-eyeper array in which a large number of glass step index type 7-eyepers are arranged is used in an imaging device, incident light and reflected light are guided by individual 7-eyepers. Since light can be produced, the utilization efficiency is high due to less light loss and light leakage, and has the effect of ensuring a high 3/N ratio. Furthermore, each element of the device has a high degree of freedom in arrangement, polishing is easy, and it is also possible to integrate it with a light emitting element using the flexibility of plastic fiber. These are effects that appear when used together with a light source and an image sensor.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of an image transfer element of an imaging apparatus according to the present invention. FIGS. 2 and 3 are cross-sectional views showing another embodiment of the present invention. 4 and 5 are cross-sectional views showing conventional examples. 8ff, Hata J

Claims (3)

[Claims] (1) An image of an imaging device that uses a plastic fiber array in which a large number of plastic step-index fibers are arranged for light transfer in a device that reflects light from a light source onto a document and reads the document image with an image pickup device. Transfer element. (2) The fiber diameter is 1 of the reading pitch of the image sensor
/4 or less, one end of all the fibers is brought close to the document, and the other end is divided into a light source side and an image sensor side at a constant ratio. . (3) A light-emitting element that emits light toward the bent portion of the bent fiber toward the document is mounted on the fiber array or its support. Image transfer element of an imaging device.