JPH07288649A - Close contact sensor case and close contact sensor having it - Google Patents

Abstract

PURPOSE:To provide the case for a close contact sensor and the close contact sensor having it by selecting an angle of a light emission side opening of a nonmagnification image forming lens hold section to be larger than a maximum incident angle of an incident light. CONSTITUTION:A projection holding a nonmagnification image forming lens SLA2 at the side of a sensor 1 is set to have an angle over a maximum incident angle with respect to an optical axis (a) of the SLA2 to eliminate a light emitted to an opening wall face 6a through the SLA 2. Thus, no stray light A is generated and an image is read with high contrast and high fidelity in the case of reading the image. Furthermore, when the case is made of a resin, the opening has only to be revised in matching with a shape of the die for the forming.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact type sensor housing and a contact type sensor having the same. More specifically, the present invention relates to a contact type sensor for projecting an image on a document onto the sensor through an array of imaging lenses of equal magnification. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact-type sensor casing preferably used for a mold line sensor and a contact-type sensor having the same.

[0002]

2. Description of the Related Art In a device such as a facsimile or an image scanner, a one-dimensional sensor (line sensor) used for inputting an image is roughly divided into a document to be read, which is reduced and projected by a lens system. It is classified into a reduction type that receives the light and a uniform type that receives an image having the same size as the original, that is, the same width.

[0003] Further, for a unit having a unit magnification, a unit using an unit magnification imaging lens and a perfect contact type not using such a lens are used. Among them, the unit magnification imaging lens is used. An example of the line sensor is shown in FIG.

In this example, an equal-magnification imaging lens represented by SELFOC lens array (trade name) (hereinafter referred to as SLA) manufactured by Nippon Sheet Glass Co., Ltd. is used. SLA, 3 is an LED array as an illumination means for illuminating the original, 4 is a protective glass on which the original 5 is placed in close contact, 6 is a case in which these are integrally incorporated as a unit, 8 is a cover for the case Is. Here, the housing 6 also has a function as an SLA holding member.

However, normally, the line sensor 1, the SLA 2, the LED array 3 and the like are incorporated in the housing 6, the focus of the optical system is adjusted, and other electrical characteristics are adjusted, and the unit 6 is used as a unit. Shipped.

[0006]

In the contact type line sensor having the above structure, a desired light beam for forming an image, that is, a light beam other than light having image information (stray light).
Sometimes reached the line sensor through various routes. The incidence of such stray light, which is unnecessary light, causes deterioration of image reading such as reduction in contrast of image information to be read.

The path of such stray light will be described with reference to FIG. For convenience, the two types of stray light will be described separately as stray light A and stray light B.

A: A ray outside the optical axis is reflected by the wall surface 6a of the opening of the SLA holding member 6 and reaches the line sensor 1. B: Reflected by the surface of the line sensor 1 or a transparent resin for protecting the line sensor. A light ray is reflected by the SLA holding member 6 again and reaches the line sensor.

In order to attenuate such stray light, S
A method such as painting the surface of the LA holding member 6 in black can be considered, but the gas of the paint accompanying the painting may fall on the surface of the line sensor and cause an image reading defect for a reason other than stray light. Further, minute paint skips due to painting may adhere to unnecessary portions and adversely affect image reading. In addition, there is a problem that the cost increases due to the addition of the painting process, and a measure not relying on the painting has been desired.

Therefore, an object of the present invention is to provide a contact sensor housing that solves the above-mentioned problem of stray light and a contact sensor having the housing.

Another object of the present invention is to provide a housing of a contact type sensor and a contact type sensor having the same, which solves the problem of stray light without increasing the cost associated with a surface treatment process such as painting. And

A further object of the present invention is to provide a contact sensor housing which is low in cost and easy to assemble, and a contact sensor having the housing.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an equal magnification imaging lens (S) for guiding light incident on a sensor for photoelectrically converting incident light.
In a case of a contact type sensor having a unit for holding an equal-magnification imaging lens for holding LA), the angle of the light exit side opening of the unit for holding the same-magnification imaging lens is set to the same-magnification imaging lens. The object of the present invention is achieved by a case of a contact type sensor having a larger incident angle than that of the incident light and a contact type sensor having the case.

Further, the present invention provides a housing of a contact-type sensor having a holding portion for holding an equal-magnification imaging lens for guiding light incident on a sensor for photoelectrically converting incident light. Of the contact type sensor in which the opening angle of the sensor-side opening of the sensor is larger than the maximum incident angle of the incident light on the equal-magnification imaging lens, the sensor for photoelectrically converting the incident light, and the light to be incident on the sensor. And a casing of a contact-type sensor having a holding portion for holding the equal-magnification imaging lens, wherein the casing is on the sensor side of the holding portion. The above object is achieved by the contact type sensor in which the opening angle of the opening is larger than the maximum incident angle of the incident light on the equal-magnification type imaging lens.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details will be described below with reference to FIGS. 3, 4 and 5.

As described above, the stray light A has a ray incident obliquely with respect to the optical axis α of the ALA 2 (this ray does not participate in the intended image formation), but is emitted at the same angle even after passing through the SLA. This is caused by reflection on the wall surface 6a of the opening shown in FIG.

On the other hand, due to the image forming characteristics of the SLA, as shown in FIG. 4, a light ray incident at an angle of the maximum incident angle Θ ₀ or more with respect to the optical axis α does not exit from the SLA. Therefore, as shown in FIG. 5, when the opening of the SLA holding member 6 has an opening angle θ that is greater than or equal to the maximum incident angle Θ _{0 with} respect to the optical axis α, stray light A generated on the wall surface 6a of the opening is generated. Can be prevented.

That is, the opening angle θ of the wall surface 6a of the opening is SL
By setting the maximum incident angle θ ₀ or more with respect to the optical axis α of A, the light 6b emitted from the SLA is not reflected by the opening wall surface 6a, and thus the generation of the stray light A is prevented. is there.

As for the stray light B, as shown in FIG. 3, the light rays mainly formed on the (line) sensor 1 are reflected on the surface of the sensor 1 or the surface of the transparent resin for protecting the sensor, and further S
The surface 6c of the LA holding member 6 facing the sensor is reflected again and reaches the sensor.

The stray light B is not necessarily removed, but it is preferably removed or sufficiently attenuated in order to read an image with higher contrast.

In order to effectively prevent such stray light B, it is preferable to provide, for example, a sawtooth groove or a step on the surface of the portion of the housing facing the sensor. By forming such a groove or step, it is possible to prevent or reduce the light reflected by the sensor or the protective member of the sensor from returning to the sensor again, thereby solving the problem caused by the stray light B. .

In this case, it is important that the line connecting the sensor-side ends of the sawtooth-shaped groove or the step has an angle equal to or larger than the maximum incident angle of light to the SLA.

FIG. 1 shows an example in which the opening on the sensor side of the housing of the contact type sensor is set to an angle not smaller than the maximum incident angle of the SLA.

As shown in the schematic sectional view of FIG. 1, S
The sensor 1 side of the protrusion that holds (supports) LA2 is S
When the angle of incidence is equal to or larger than the maximum incident angle with respect to the optical axis α of LA2, the light radiated through the SLA2 on the opening wall surface 6a is eliminated.

Therefore, the above-mentioned stray light A is not generated, and when the image is read, the image can be read with extremely high contrast and faithfulness.

The opening is formed by a frame (for example, SLA).
When the (holding member) is formed by molding resin, etc., the shape of the mold can be changed according to the opening. When it is formed by processing metal, etc., it can be processed in the normal cutting process, so it is costly. There is almost no.

In addition, since the light itself is prevented from reaching the antireflection caused by the application of the paint, there is essentially no change over time in order to prevent the generation of stray light, and total maintenance including maintenance is performed. The cost can also be reduced.

Next, an example in which the stray light B is treated will be described with reference to the schematic sectional view shown in FIG.

FIG. 6 shows the sensor 1 and the SLA holding member 6 portion in the vicinity of the sensor 1. As shown in the drawing, a sawtooth step 6e is formed on the surface of the SLA holding member 6 corresponding to the sensor 1.

As a result, the light reflected by the sensor 1 and the sensor protection member is prevented from returning to the sensor 1 again by the sawtooth step 6e, so that stray light can be prevented or reduced.

Further, as shown in FIG. 7, the opening wall surface 6
A stepped or sawtoothed step 6d may be provided in a.
This can prevent or reduce stray light caused by reflected light from the sensor 1 or the sensor protection member entering the opening 6a.

As described above, the step 6d shown in FIG.
It is desirable that the line connecting the protrusions is at an angle larger than the maximum incident angle of SLA2.

FIG. 8 shows an example in which the steps shown in FIGS. 6 and 7 are combined. With this configuration, it is possible to further prevent or reduce the generation of stray light.

These steps can also be formed by a mold or cutting during molding.

The sensor 1 in each of the above embodiments may be a line sensor, in which case it may be a multi-chip type sensor in which a plurality of sensor chips are continuously arranged on a long substrate, or 1 It is also good as a sensor with no joints or joints as one sensor. It is preferable that the housing such as the SLA holding member 6 is integrated according to the length of the sensor, but it may be divided and assembled into a plurality of pieces if necessary.

[0036]

As described above, according to the present invention, it is possible to prevent stray light without applying a special surface treatment, and it is possible to provide a high performance and low cost contact type sensor.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a contact sensor according to the present invention.

FIG. 2 is a schematic cross-sectional view of a conventional contact sensor.

FIG. 3 is a diagram for explaining stray light of the contact sensor.

FIG. 4 is an explanatory diagram of light rays passing through an equal magnification imaging lens (SLA).

FIG. 5 is a schematic cross-sectional view of the contact sensor of the present invention.

FIG. 6 is a schematic cross-sectional view of the contact sensor of the present invention.

FIG. 7 is a schematic sectional view of the contact sensor of the present invention.

FIG. 8 is a schematic sectional view of the contact sensor of the present invention.

[Explanation of symbols]

 1 Sensor 2 Equal-magnification Imaging Lens (SLA) 3 LED Array 4 Protective Glass 5 Document 6 Housing 6a Opening Wall 6b Light Emitted from SLA 6c Face of Sensor 6e Step

Claims (7)

[Claims] 1. A housing of a contact-type sensor having a holding portion for holding an equal-magnification imaging lens for guiding light incident on a sensor for photoelectrically converting incident light, in the housing side of the holding portion. A housing of a contact-type sensor, wherein an opening angle of the opening is made larger than a maximum incident angle of incident light to the equal-magnification imaging lens. 2. The housing of the contact type sensor according to claim 1, wherein a step is formed on at least a part of a surface of the housing facing the sensor. 3. The housing of the contact type sensor according to claim 2, wherein the step is provided in a sensor-side opening of the housing. 4. A contact type sensor having a sensor for photoelectrically converting incident light, a unit magnification imaging lens for guiding light to be incident on the sensor, and a holding unit for holding the unit magnification imaging lens. In the contact sensor, the housing has an opening angle of the sensor-side opening of the holding portion that is larger than a maximum incident angle of incident light to the equal-magnification imaging lens. Contact type sensor. 5. The contact sensor according to claim 4, wherein a step is formed on at least a part of a surface of the housing facing the sensor. 6. The housing of the contact sensor according to claim 5, wherein the step is provided in an opening on the sensor side of the housing. 7. The contact sensor according to claim 4, wherein the sensor is a line sensor.