JPH0720928Y2 - Light sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an optical sensor for reading an original used in a facsimile, a digital copying machine, an image scanner, etc. The present invention relates to an end-face incident type optical sensor that is incident from an end face, propagates the incident light image to a light receiving element through an optical waveguide, and reads a document image.

(Prior Art) Conventionally, as an optical sensor for reading an original used in a facsimile or the like, a light source such as a fluorescent lamp irradiates the original with illumination light, and reflected light from the original is coupled to a light receiving element such as a CCD by a lens. The image is read, and the original image is read by photoelectric conversion by the light receiving element.

However, when an image of a document is formed on the light receiving element by using a lens like the optical sensor, the ratio of the amount of light incident on the light receiving element to the amount of light emitted from the light source that illuminates the document is almost equal to that of the lens. It was decided by the F value, and there was a drawback in that a light source with a very small amount of light of at most several percent and a large amount of light was required. Further, when an image of a document is formed on a light receiving element using a lens, the optical path length from the document to the light receiving element is determined by the focal length of the lens and the like, which makes it difficult to downsize a device such as a facsimile. there were.

Therefore, in order to eliminate the drawbacks of the above-mentioned optical sensor for reading the original, an optical sensor has been proposed which detects the original image by utilizing the optical waveguide to propagate the original image to the light receiving element.

FIG. 5 shows an example of an optical sensor using the above-mentioned optical waveguide. This optical sensor is provided with an optical waveguide layer 23 and a light receiving element 24 on a substrate 22, and is arranged so as to face the image forming surface of a document 25. An original image is made incident from one end surface of the optical waveguide layer 23, and the original image is propagated to the light receiving element 24 through the optical waveguide layer 23 to detect the original image.

(Problems to be Solved by the Invention) By the way, in the end-face incidence type optical sensor having the structure shown in FIG. 5, in order to keep the light amount of the reflected light reflected from the document 25 and the resolution with the adjacent bit constant, Surface and optical waveguide
It is required to control the distance between the end surface 23a of 23 and the end surface 23a accurately and accurately.

Therefore, in the document reading apparatus using the conventional end-face incident type optical sensor 21, as shown in FIG.
In the vicinity of the end surface 22a of the substrate 22 and the end surface 23a of the optical waveguide 23, a mechanism system such as rollers 26, 27, 28, 29 for conveying and fixing the document 25 is provided, and the mechanism of the rollers 26, 27, 28, 29 etc. A method of controlling so that the distance between the light receiving side end face 23a of the optical waveguide 23 and the document surface is always kept constant by a system, or as shown in FIG. 6, the substrate 32 of the optical sensor 31 and the optical waveguide A method has been performed in which a transparent plate 36 for spacers is attached between the end face of 33 and the document to keep the distance between the end face of the substrate 32 and the optical waveguide 33 and the document face constant.

However, since the distance between the end surfaces of the optical sensors 21 and 31 and the document surface usually needs to be controlled to about 10 μm to 50 μm, the method shown in FIG. 5 accurately controls the distance on the order of μm. Is very difficult, and a complex and precise mechanical system is required for accurate control, the parts cost of the mechanical system is expensive, and assembly and adjustment are troublesome, which is a factor of high cost. In addition, as shown in FIG. 6, the transparent plate 36 for the spacer is attached between the optical sensor 31 and the original 35 to keep the distance between the original surface and the substrate and the end face of the optical waveguide constant. Since the transparent plate 36 having a desired plate thickness may be attached, the distance can be accurately controlled, but the transparent plate 36 having a plate thickness of 10 μm to 50 μm is usually attached to the end face of the substrate having a thickness of 1 mm to 2 mm. It is very difficult to stick together, and the spacer Since the original side surface of the bright plate 36 is always in contact with the original surface, the original 35 often scratches or abrades the original side surface of the spacer transparent plate 36, so that the light from the optical sensor 31 is incident on the original. The surface, that is, the surface of the transparent plate 36, becomes cloudy, resulting in detection failure or S /
This is a problem because it may cause a decrease in the N ratio.

The present invention has been made in view of the above circumstances, and it is possible to control the distance between the document surface and the incident side end surface of the optical waveguide with a simple structure, and the above-mentioned light incident side end surface may be damaged or worn. It is an object of the present invention to provide an end-face incidence type optical sensor that can realize high resolution of the optical sensor without any problem.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, an original image is incident from one end face of the optical waveguide which is provided with an optical waveguide and a light receiving element on a substrate and is arranged to face the original face. Then, in an end-face incident type optical sensor that detects the original image by propagating the original image to the light receiving element through the optical waveguide, the original surface comes into contact with the end surface of the substrate on the light incident side of the optical waveguide when reading the original. And the document is slid along the end face of the substrate, and
The document-side end surface of the optical waveguide is formed so as to be retracted from the document-side end surface of the substrate by a predetermined distance.

In addition to the above configuration, a groove for receiving abrasion powder is formed on the end surface of the substrate on the original side.

(Operation) In the optical sensor according to the present invention, since the end surface of the optical waveguide on the original side is set back from the original end surface of the substrate by a predetermined distance with respect to the original, the end surface of the substrate and the original surface are separated from each other. The distance between the light-incident side end surface of the optical waveguide and the document surface can be kept constant only by making contact.

Further, according to the present invention, the distance between the light incident side end surface of the optical waveguide and the document surface can be kept constant without interposing a special spacer or the like. Are prevented, and the incident surface is prevented from being scratched or worn.

Further, in the optical sensor in which the groove for receiving the abrasion powder is formed on the end surface of the substrate on the original side, the abrasion powder such as paper dust generated during the sliding contact between the substrate end surface and the original is taken into the groove portion and It is possible to prevent the abrasion powder from adhering to the incident side end surface.

(Embodiment) Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings.

FIG. 1 is a schematic side view of an optical sensor according to an embodiment of the present invention, in which reference numeral 1 indicates an optical sensor and reference numeral 5 indicates an original.

Here, the optical sensor 1 according to the present invention comprises an optical waveguide layer 3 and a light receiving element (photoelectric conversion element) 4 on a substrate 2, and one end surface 3a of the optical waveguide 3 arranged to face the original surface.
Is an end-face incident type optical sensor 1 which receives an original image from the optical waveguide 3 and propagates the original image to the light receiving element 4 through the optical waveguide 3 to detect the original image.
The document surface is brought into contact with the substrate end surface 2a on the light incident side of the document, and the document 5 is slid along the substrate end surface 2a, and the document side end surface 3a of the optical waveguide 3 is the document of the substrate 2. Side edge
Predetermined distance from the document surface 5 rather than 2a (usually 10 μm to 50 μm
It is characterized in that it is formed by retreating by (μm) d.

That is, in the optical sensor 1 according to the present invention, the end surface 3a of the optical waveguide 3 on the original side is formed to be retracted from the original end surface 2a of the substrate 2 with respect to the original 5 by a predetermined distance d. If the end face 2a of the optical disc 2 is in contact with the original face and the original 5 is made to travel in contact with the substrate end face 2a, the distance between the light incident side end face 3a of the optical waveguide 3 and the original face is automatically set. d
Is controlled to be kept constant.

Further, according to the above configuration, the distance d between the light incident side end surface 3a of the optical waveguide 3 and the document surface can be automatically kept constant without interposing a special spacer or the like.
The contact between the light-incident side end surface 3a and the original 5 is completely prevented,
The light incident surface 3a is prevented from being scratched or worn.

Therefore, in the optical sensor 1 according to the present invention, despite the simple structure, the distance d between the end surface 3a of the optical waveguide 3 on which the original image is incident and the original surface is always kept constant, and
Since the light incident end surface 3a of the optical waveguide 3 is not clouded due to scratches, abrasion, etc., it is possible to easily realize cost reduction, high resolution, and improvement of S / N ratio of the optical sensor 1.

Next, a method of manufacturing the optical sensor according to the present invention, an example of which is shown in FIG. 1, will be briefly described with reference to FIG.

First, as shown in FIG. 2 (I), an optical waveguide layer 3 is laminated and formed on a substrate 2 made of glass, semiconductor, or the like, and light is received on the end face side opposite to the light incident side end face of the optical waveguide layer 3. Element 4
To form a basic optical sensor, and the light-incident-side end surface of the optical sensor is smoothly cut to form a light-incident surface.

Next, as shown in FIG. 2 (II), after forming a resist layer 6 on the optical waveguide layer 3 and the light receiving element 4 of the optical sensor formed in the above process, an optical waveguide layer is formed by a patterning process. The resist layer from the light incident side end face 3a of 3 up to a predetermined distance d is removed.

Next, as shown in FIG. 2 (III), the optical sensor on which the resist layer 6 is formed and patterned in the previous step is etched to remove the resist layer removed portion of the optical waveguide layer 3 and The light incident side end surface of the layer 3 is set back from the end surface of the substrate 2 by a predetermined distance d.

Then, after this, as shown in FIG. 2 (IV), the resist layer 6 is removed to obtain the optical sensor 1 according to the present invention.

The optical sensor 1 includes a substrate 2, an optical waveguide 3, a light receiving element 4, a light shielding layer for preventing stray light from entering the optical waveguide and the light receiving element, and a signal from the light receiving element. Although an electrode for this purpose is provided, it is omitted in the figure.

Although the manufacturing process of the optical sensor according to the present invention has been described above with reference to FIG. 2, the optical sensor according to the present invention is easy to manufacture and does not increase the manufacturing cost.

Therefore, according to the present invention, it is possible to provide an end-face incidence type optical sensor that has a simple structure and can control the distance between the original and the end face of the optical waveguide to be kept constant without increasing the manufacturing cost.

Next, another embodiment of the optical sensor according to the present invention will be described with reference to FIG.

FIG. 3 is a schematic side view of an optical sensor showing another embodiment of the present invention, in which reference numeral 1 is an optical sensor, reference numeral 2 is a substrate, reference numeral 3 is an optical waveguide layer, reference numeral 4 is a light receiving element, Code 5
Indicates a manuscript, and reference numeral 7 indicates a light source, respectively, and the basic configuration is the same as that shown in FIG.

Here, the optical sensor 1 according to the present embodiment is configured on the assumption that the light source 7 is installed obliquely above the optical sensor 1, and the light source 7 is oblique with respect to the optical sensor 1. Even when the optical waveguide 3 is installed above, the light incident side end face 3a of the optical waveguide 3 is slightly inclined in the light incident direction so that the incident light can easily enter the optical waveguide 3.

That is, when the light source 7 is installed obliquely above the optical sensor 1, the light emitted by the light source 7 and reflected by the document surface is reflected obliquely with respect to the document 5, and therefore the light source 7 shown in FIG. If the end face of the optical waveguide is almost parallel to the document surface as in the optical sensor shown, part of the light from the document surface is reflected by the end face, and the amount of light incident on the optical waveguide is reduced, resulting in insufficient light amount. However, in the case of the optical sensor shown in FIG. 3, on the other hand, since the end face 3a of the optical waveguide 3 on the light incident side is slightly inclined in the light incident direction, the end face 3a The incident light easily enters the optical waveguide 3, and the light amount does not become insufficient. As shown in FIG. 3, when the light source 7 is located on the optical waveguide 3 side of the optical sensor, a light shielding layer is formed on the upper surface side of the optical waveguide layer 3 so that the light from the light source 7 can be directly guided. It is prevented from entering the waveguide.

By the way, in the optical sensor having the configuration shown in FIG. 1 and FIG. 3, when the original 5 is run while the optical sensor 1 is in contact with the original 5, the original 5 is slidably contacted with the end surface of the substrate 2. 5 may wear and generate abrasion powder such as paper dust. If this abrasion powder adheres to the light incident side end surface 3a of the optical waveguide 3 of the optical sensor 1, the incidence of light on the optical waveguide 3 is blocked. , Which may cause detection failure.

Therefore, in order to prevent the occurrence of such a problem, the corners of the end surface of the substrate 2 of the optical sensor 1 which comes into contact with the original are slightly rounded, or the end surface of the substrate 2 is subjected to Teflon coating or the like, so that it is not worn. Although a method of treating the end surface so as to be difficult can be considered, it is impossible to completely prevent the abrasion only by this method.

Therefore, in the present invention, in order to solve the above problems, an optical sensor is constructed as shown in FIG.

Here, FIG. 4 is a schematic side view of an optical sensor. In the figure, reference numeral 1 is an optical sensor, reference numeral 2 is a substrate, reference numeral 3 is an optical waveguide layer, reference numeral 4 is a light receiving element, and reference numeral 5 is an original document, respectively. Although the basic structure is similar to that shown in FIGS. 1 and 3, in the present embodiment, in addition to the above structure, a groove 2b for receiving abrasion powder is formed on the end face of the substrate 2 on the original side. And the abrasion powder generated by the sliding contact between the original 5 and the end surface of the substrate 2 is formed in the groove.
It is configured so that it is taken into the inside of 2b and does not go out to the light incident side end face 3a side of the waveguide 3. Therefore, in the optical sensor 1 having the configuration shown in FIG. 4, the abrasion powder generated by the sliding contact between the original 5 and the substrate 2 is collected in the groove 2b on the end face of the substrate 2, so that the light incident side end face of the waveguide 3 is collected. The abrasion powder does not adhere to 3a, and it is possible to prevent the detection failure due to the adhesion of the abrasion powder.

(Effect of the Invention) As described above with reference to the illustrated embodiment, in the optical sensor according to the present invention, the end face of the optical waveguide on the original side is retracted from the end face of the substrate on the original side by a predetermined distance with respect to the original. Since the end surface of the substrate and the original surface are in contact with each other and the original is moved while being in contact with the end surface of the substrate, the edge between the light incident side end surface of the optical waveguide and the original surface is automatically The distance is controlled to be kept constant.

In addition, according to the present invention, the distance between the light incident side end surface of the optical waveguide and the document surface can be automatically kept constant without interposing a special spacer or the like. The contact between the end surface and the original is completely prevented, and the light incident surface is prevented from being scratched or worn.

Therefore, in the optical sensor according to the present invention, despite the simple structure, the distance between the end surface of the optical waveguide on which the original image is incident and the original surface is always kept constant, and the light incident end surface of the optical waveguide is damaged. Since it does not become cloudy due to wear or abrasion, it is possible to easily realize cost reduction, high resolution, and improvement of S / N ratio of the optical sensor.

In addition, in the optical sensor according to the present invention, in addition to the above-mentioned structure, the groove for receiving the abrasion powder is formed on the end surface of the substrate on the original side, so that the abrasion powder generated by the sliding contact between the original and the end surface of the substrate can be stored in the groove. Since it is recovered, the abrasion powder is prevented from adhering to the light incident side end surface of the waveguide, and the detection failure due to the abrasion powder adhesion can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic side sectional view of an optical sensor showing an embodiment of the present invention, FIG. 2 is an explanatory view showing a manufacturing process of the same optical sensor, and FIG. 3 shows another embodiment of the present invention. FIG. 4 is a schematic side sectional configuration diagram of an optical sensor, FIG. 4 is a schematic side sectional configuration diagram of an optical sensor according to yet another embodiment of the present invention, and FIGS. 5 and 6 are different prior art examples. It is a schematic side cross-sectional block diagram of an optical sensor. 1 ... Optical sensor, 2 ... Substrate, 2a ... End surface of original on substrate, 2b ... Groove for receiving abrasion powder, 3 ... Optical waveguide, 3a ...
End surface of the optical waveguide on the original side, 4 ... Light receiving element, 5 ... Original,
7 ... Light source.

Claims (2)

[Scope of utility model registration request] 1. An optical waveguide and a light receiving element are provided on a substrate, and an original image is made incident on one end surface of the optical waveguide opposite to an original surface, and the original image is passed through the optical waveguide to the light receiving element. In an edge incident type optical sensor for propagating and detecting a document image, the document surface is brought into contact with the light incident side substrate end face of the optical waveguide when the document is read, and the document is slid along the substrate end face. In addition, the optical sensor is characterized in that the end face of the optical waveguide on the original side is formed so as to be retracted from the end face of the substrate on the original side by a predetermined distance with respect to the original. 2. The optical sensor according to claim 1, wherein a groove for receiving abrasion powder is formed on an end surface of the substrate on the original side.