JPH04101557A - Structure of optical system of contact type image sensor - Google Patents

Abstract

PURPOSE:To efficiently guide loss light such as stray light to the surface of illumination that is the end face of the light guiding body for intensifying the degree of illumination of the surface of reading an original by using a light guiding body that can efficiently guide a light received on a surface to the end face (cross section) and that can illuminate the light from the end face for covering an illuminant. CONSTITUTION:Light guiding body 7 that covers a LED array 6a efficiently guides a light 9g received on the light receiving surface 7d of light guiding body to an illuminating surface 7c that is the end face. A light 9i that is emitted in a direction other than the direction toward the original reading surface 8a from the light emitting surface 6c of LED array 6a is received on the receiving surface 7d of a PC light guiding body 7 and incorporated in the PC light guiding body 7. This incorporated light 9i in conjunction with a light 9h emitted from the light emitting surface 6c of LED array 6a in the direction toward the original reading surface 8a can be projected to the original reading surface 8a. The intensity of the illumination from the illuminating surface 7c is evenly projected toward the main scanning direction. With this, a loss light such as stray light can be guided efficiently to the illuminating surface that is the end face of the light guiding body, thereby being able to realize upgrading of illumination of the original reading surface.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a contact type image sensor used in facsimile devices, image scanners, and the like.

<Prior art> Conventionally, this type of contact-type image sensor, for example,
It is used in the laser facnomy device shown in Figure 6.

This laser facsimile device has a reading section 5 as shown in the figure.
5, a transmission control section 56 and a recording section 57.

The reading section 55 includes an image sensor unit 64 that irradiates light from a light emitter 60 onto a document 62 on a document table 61 and reads the document 62 with a light receiving element 63 .

The transmission control unit 56 includes a data memory 65 that stores data from the reading unit 55, a data modulation/demodulation circuit 66 that modulates and demodulates the data, and a modem 67.

The recording unit 57 includes a laser diode 69 that irradiates the signal from the transmission control unit 56 with a laser beam, and a photoreceptor 73 that is exposed to the beam from the laser diode 69.
It has a developer tank 74 for developing the photoreceptor 73, a transfer device 76 for transferring the developed image of the photoreceptor 73 onto a transfer paper 75, and a charger 77 for charging the photoreceptor 73.

A contact type image sensor used in such a facnomy device will be described in detail with reference to FIGS. 14 and 15.

Figures 14 and 15 are cross-sectional views illustrating the prior art in a simplified manner for convenience. Note that FIG. 15 also shows an illuminance graph.

The contact type image sensor shown in FIG.
2, a light emitting array (hereinafter referred to as LED array) substrate 6, an image display substrate 4, and a fiber array plate (hereinafter referred to as FAP) 2.3 are internally supported,
A light shielding portion +2a is formed in this haunock to prevent the light emitted from the LED array 6a from directly entering the light receiving element 4a.

In addition, there is no absorber for absorbing light leakage on the image sensor substrate 4, and the so-called CL consists of a core and a crut.
An E MA (ExtraMural A) having an EAR type optical fiber array plate 2 and the absorber described above.
bsorption) type optical fiber array plate 3
and are arranged in a stacked manner. and a support material for the CLEAR type optical fiber array 2a of the CLEAR type FAP2, and
A base plate 2b, which is a transparent document support material, is also arranged on the LED array board 6.

In the above configuration, the light 9h emitted from the light emitting surface 6c of the LED array 6a toward the document reading surface 8a and the housing 1
2 and the base plate 2b, and is reflected diffusely onto the original reading surface 8a.
The part 9f of the scattered light that reaches 9f becomes effective illumination light for the document reading surface 8a.

However, in this structure, the light emitting surface 6c of the LED array 6a
Most of the light 91 emitted from the housing 12 and the base plate 2b in directions other than the direction toward the document reading surface 8a is emitted from the housing 12 and the base plate 2b.
It simply attenuates by repeating absorption and diffuse reflection. Furthermore, these lights pass through the base plate 2b and become lost light 9d such as stray light that leaks out of the image sensor unit, and do not work as illuminating light for the document reading surface 8a. Moreover, the total amount of the lost light 9d is larger than the illumination light.

In other words, this structure wastes much of the light emitted by the LED array 6a.

The above structure also includes an LED array 6a and a document reading surface 8.
Since only the transparent base plate 2b is interposed between the LED arrays 6a and 1b, as shown in FIG. In addition, as the image sensor unit becomes smaller and thinner, the distance between the LED array 6a and the document reading surface 8a becomes shorter, so the structure is such that the variation in illuminance on the document reading surface 8a tends to increase due to the influence of ripples. be.

That is, FIG. 15 shows the influence of ripples on the LED array 6a in the prior art in a simplified manner for convenience, and in detail, in the figure, light emitted from arbitrary LEDs 20 and 21 of the LED array 6a lined up in the main scanning direction 1b. is incident on the surface of the base plate 2b on the side of the LEDs 20 and 21, and since the angle of incidence is small on the LED upper shield 50.51, the reflected light 40.41 is relatively weak (indicated by the broken line). The light incident on the other hand and taken into the base plate 2b is relatively strong (shown by a solid line).

In addition, near the LED gap 52, the incident angle is large, so the reflected light 40.41 is relatively strong (indicated by the solid line) a
The light incident on the other hand and taken into the base plate 2b is relatively weak (indicated by a broken line).

In L, near the upper part of the LED 50, light emitted from the LED 20 with a small incident angle and light emitted from the LED 21 with a large incident angle enter the LED 20 of the base plate 2b.
．． Relatively strong light (relatively strong light between light 30a and light 30b) and relatively weak light (relatively weak light between light 31a and light 30b) that is refracted by the surface on the 21 side and taken into base plate 2b. overlap and reach the illumination surface 30.

Similarly, near the upper part of the LED 51, the light emitted from the LED 21 is 1.
The light with a small incident angle and the light with a large incident angle emitted from the LED 20 are incident, and while being refracted by the surface of the base plate 2b on the LED 20.2+ side, the relatively strong light (light 31e) taken into the base plate 2b is (relatively strong light between 31f and 31f),
Relatively weak light (relatively weak light between light 30e and light 30f) reaches the illumination surface 30 in an overlapping manner.

However, near the upper part 52 between the LEDs, the light emitted from the LED 20 with a large incident angle and the light emitted from the LED 21 with a large incident angle enter the LEDs 20, 2+ on the base plate 2b.
Relatively weak light (relatively weak light between 30C and 30d) that is refracted by the side surface and taken into the base plate 2b;
Relatively weak light (relatively weak light between 31c and 31d) reaches the illumination surface 30 in an overlapping manner.

A large difference in illuminance 54 occurs between the illuminance of the illumination surface 30 between the upper LEDs 50 and 51 and the upper portion 52 between the LEDs.

As described above, by irradiating the illumination light from the illumination surface 30 in the main scanning direction 1b, the structure becomes such that large variations in illuminance are likely to occur on the document reading surface 8a.

<Problems to be Solved by the Invention> In recent years, with the personalization of image input/output devices such as facsimile devices and word processors, they have become smaller and more handy. There is a demand for smaller and thinner devices.

For this reason, there is a strong demand for miniaturization and thinning of the illumination system for the document reading surface, which is a component of the contact type image sensor unit. The cylindrical lens (rod lens) used to condense the light from the light emitter was abolished, but this reduced the illuminance on the document reading surface, resulting in a decrease in the S/N' ratio of the image sensor's output signal. There was a problem.

In addition, most of the light that effectively acts as illumination light is emitted from the LED array in the direction of the original reading surface (some indirect light is incident), and most of the light emitted in other directions,
There has been a problem in that light is repeatedly absorbed and diffusely reflected by the housing and base plate, which are the constituent materials of the image sensor unit around the D array, resulting in lost light such as stray light that is only attenuated or leaked outside the unit.

Furthermore, as a measure to prevent a decrease in illuminance, it may be possible to increase the number of LEDs in the LED array, but in this case, there is a problem of increased costs.

The present invention has been made in consideration of the above-mentioned circumstances, and it is possible to make the illumination system smaller and thinner by making the light emitting body smaller, eliminating the cylindrical lens, and shortening the distance between the light emitting body and the document reading surface. It is an object of the present invention to provide a single contact type image sensor having an illumination system for the document reading surface that makes it possible to increase the illuminance of the document reading surface, reduce variations in illuminance, and roughly reduce the number of LEDs in the LED array.

<Means for solving the problem> The means for solving the problem according to claim 1 of the present invention is as shown in FIG.
In a contact image sensor that includes a light emitter that illuminates a document to be read and a light receiving element that converts reflected light from the document into an electrical signal, the light emitter receives the light on its surface and emits light from the illumination surface. It is covered with a light guide made of a material that can efficiently and uniformly irradiate the document, and the light guide guides the lost light from the light emitter to illuminate the document reading surface.

The problem solving means according to claim 2 of the present invention is as shown in FIG.
A light shielding/reflecting material is provided on the end surface of the light guide other than the illumination surface,
Further, a light shielding/reflecting material is provided between the light guide and the light receiving element to prevent stray light from entering the light receiving element.

The problem solving means according to claim 3 of the present invention is as shown in FIG.
The light guide has a flat light-receiving surface that is perpendicular to the light on an extension of the light-emitting source of the light-emitting body, or an arcuate light-receiving surface centered on the light-emitting source that is perpendicular to the light.

The problem solving means according to claim 4 of the present invention is as shown in FIG.
By configuring the light-receiving surface of the light guide to have a predetermined angle with respect to the outer surface, the light from the light emitter is reflected by the outer surface and the amount of lost light transmitted through the outer surface is reduced. It is something.

The problem solving means according to claim 5 of the present invention is as shown in FIG.
The light guide responds to light on a straight line connecting the light emitting source of the light emitter and the center of the document reading surface, and light on a group of straight lines connecting any part of the light emitting surface of the light emitter to the center of the document reading surface. An arcuate light-receiving surface is formed with the center of the document reading surface orthogonal to the center of the document reading surface. By forming an arc-shaped illumination surface centered on the center of the document reading surface, reflection of light from the surface light emitter on the light receiving surface and the illumination surface is reduced.

The problem solving means according to claim 6 of the present invention is
As shown in the figure, by forming a light guide or a slit hole along a group of straight lines connecting the light emitting source of the light emitting body and an arbitrary part of the light emitting surface and the document reading surface, light incident along the group of straight lines is formed. This reduces the attenuation caused by reflection, absorption, etc. in the light guide.

As shown in FIG. 12, the means for solving the problem according to claim 7 of the present invention is to form a convex lens-shaped illumination surface part on the light guide, thereby condensing one light beam that enters the illumination part. .

The means for solving the problem according to claim 8 of the present invention is, as shown in FIG. Further, by forming a surface perpendicular to the light on the straight line connecting the light emitting source of the light emitting body and the center of the document reading surface, reflection on the surface of the base plate is reduced.

The problem solving means according to claim 9 of the present invention is as shown in FIG.
The base plate of the fiber array plate is formed with an arc-shaped surface centered on the center of the document reading surface that is perpendicular to the light on the straight line group connecting any part of the light emitting surface of the light emitter and the center of the document reading surface. By doing so, reflection on the surface of the base plate is reduced.

<Function> In the problem solving means according to claim 1, the light emitting body is covered with a light guide that can efficiently guide light received on a surface to an end surface (cross section) and irradiate the end surface with light. Therefore, lost light such as stray light can be efficiently guided to the illumination surface, which is the end surface of the light guide, and the illuminance of the document reading surface can be increased.

Moreover, this makes it possible to improve the SZN ratio of the image sensor.

Furthermore, by reflecting and guiding light in various directions at the interface of the light guide, the intensity of the illumination light emitted from the illumination surface is made uniform in the main scanning direction, and the ripples of the light emitter can cause the document reading surface to be distorted. Reduces illuminance variations, and furthermore, L as a light emitter
It is possible to reduce the number of LEDs in the ED array.

In addition, by maximizing the above effects, we can further reduce the size of light emitters such as LED arrays, reduce the number of cylinders (rod lenses) used to collect the light of the light emitters, and reduce the distance between the light emitters and the document reading surface. The illumination system for the document reading surface can be made smaller and thinner by shortening the time.

In addition, in claim 2, polycarbonate (hereinafter referred to as PC)
By providing a reflective material on the outer surface of the light guide such as
Loss of light that leaks or passes through the surface can be eliminated, and the light can be returned to the light guide or reflected laterally to efficiently guide the light to the illumination surface, increasing the illuminance of the document reading surface. It is possible to achieve a close-up image and reduce variations in illuminance on the document reading surface due to reflected light in various directions.

Furthermore, by providing the reflective material, it is possible to block stray light from the LED array from directly entering the image sensor portion.

According to claim 3, in the light guide, a flat light-receiving surface orthogonal to relatively strong and main light incident along an extension line of a light emitting source of a light emitting body such as an LED array; Since it forms an arc-shaped light receiving surface centered on the light emitting source perpendicular to the light receiving surface, it reduces loss due to reflection of the light on the light receiving surface and efficiently captures the light into the light guide such as a PC. , it is possible to increase the illuminance on the side opposite to the document reading surface by guiding the light to the illuminance surface.

Furthermore, according to claim 4, since the light-receiving surface is formed at a predetermined angle with respect to the outer surface thereof, the light has a reflection angle depending on the angle, and the light taken into the light guide is reflected by the light-receiving surface. Reduces the amount of light that leaks out of the light body and the amount of lost light that passes through it,
Alternatively, it is possible to efficiently guide light to the illumination surface, increase the illuminance of the document reading surface, and reduce variations in the illuminance of the document reading surface due to reflected light guided in various directions.

According to claim 5, in the light guide, a relatively strong main light incident along a straight line connecting the light emitting source of the light emitting body and the center of the document reading surface, and an arbitrary light on the light emitting surface of the light emitting body. An arc-shaped light-receiving surface is formed with the center of the document-reading surface perpendicular to the main light incident along a group of straight lines connecting the center of the document-reading surface and the center of the document-reading surface. It forms an arc-shaped illumination surface centered on the document reading center that is perpendicular to the light and the guided light that goes straight to the center of the document reading surface. It is also possible to reduce reflection on the illumination surface, which is the opposite surface (back surface), and efficiently irradiate the original reading surface with the light, thereby increasing the illuminance of the original reading surface.

According to claim 6, in the light guide, a slit hole of an arbitrary width is formed in the document reading surface along a group of straight lines connecting the light emitting source of the light emitting body and any part of the light emitting surface, and the document reading surface. By forming it on the illumination surface, it is possible to eliminate the attenuation due to reflection and absorption on the PC light guide 7 of the relatively strong main light incident almost along the above-mentioned straight line, and increase the illuminance of the document reading surface. can.

According to claim 7, by forming a convex lens-shaped illumination surface portion on the light guide, direct light or reflected light from the light emitting body can be directed to the document reading surface. It is possible to increase the illuminance of the document reading surface by concentrating the light on the document.

According to claim 8, in a device using a fiber array plate that guides reflected light from an original reading surface to a light receiving element, a light emitting source of a light emitter and a center of the original reading surface are provided on a base plate of the optical fiber array. According to claim 9, a group of straight lines connecting any part of the light emitting surface of the light emitting body and the center of the document reading surface is formed. The base plate has an arc-shaped surface centered on the center of the document reading surface that is orthogonal to the main light incident along the direction of the light and the guided light that goes straight to the center of the document reading surface. It is possible to reduce the reflection of light on the surface of the base plate, efficiently irradiate the original reading surface with the light, and increase the illuminance of the original reading surface.

In addition, by forming the above-mentioned surface, it is not necessary to take into consideration the deviation of the optical axis of the light due to the refractive index of the base plate in correspondence with the base plate thickness. It has the advantage of being unaffected.

<Example> Embodiments of the present invention will be described in detail below with reference to the drawings.

[First Embodiment] FIGS. 1 to 7 are simplified illustrations of the first embodiment of the present invention for convenience. FIG. 1 is a partially cutaway perspective view of a contact type image sensor unit; Figure 2 is A- in Figure 1.
A' cross-sectional view, FIG. 3 is a cross-sectional view in the main scanning direction and an illumination graph, FIG. 4 is a cross-sectional view showing a simplified view of the main irradiation light in the main scanning direction, and FIG. 5 is a cross-sectional view showing the light shielding and reflection according to the present invention. A sectional view showing another proposed example without material, Fig. 6 is a sectional view showing that the light receiving surface of the light guide has a predetermined angle, Fig. 7 (a)
7(b) is a cross-sectional view showing the angle of the light-receiving surface and the illumination surface of the light guide with respect to the light, and FIG. 7(b) is a cross-sectional view showing the scattering state in the light guide.

Note that functional parts that are the same as those of the conventional components shown in FIGS. 14 to 16 are indicated by the same reference numerals.

As shown in the figure, the contact type image sensor according to the present invention is used, for example, in a reading section 55 (see FIG. 16) of a facsimile device, and as shown in FIG.
An LED array board 6 and an image sensor board 4 are mounted in parallel thereto.

A large number of LED arrays 6a serving as light emitters are mounted on the LED array board 6 in the main scanning direction 1b.

Further, in the main scanning direction 1b of the image sensor substrate 4, a large number of light receiving elements 4a (photodiodes) are arranged corresponding to the LED array 6a.

A light guide 7 having a U-shaped cross section and open at the bottom is provided so as to surround the LED array 6a, and the outer surface 7e of the light guide 7 is shielded from light except for the illumination surface 7c that illuminates the document l. - Covered with reflective material 7b.

Furthermore, an EMA type optical fiber array plate 3 and a CLEAR type optical fiber array plate 2 are laminated on the upper surface of the light receiving element 4a.

The EMA type optical fiber array plate 3 includes an EMA type optical fiber array 3a and a base plate 3b that supports the EMA type optical fiber array 3a.
It consists of

CLEAR type optical fiber array plate 2 is CLE
It consists of an AR type optical fiber array 2a and glass base plates 2b and 2c that sandwich and support this.

The end surface of the base plate 2b is the illumination surface 7C of the light guide 7.
It is formed into an arc shape.

The contact image sensor configured in this way has the following characteristic configurations, and its functions differ depending on the configuration. Explain.

(Structure and function of phosphor or reflector in light guide) The light guide 7 that covers the LED array 6a efficiently guides the light 9g received at the light receiving surface 7d to the illumination surface 7c, which is the end surface. It is made of polycarbonate (hereinafter referred to as PC), which is a material that allows the guided illumination light 9C to be irradiated almost uniformly. The light guide 7 has a large number of phosphors 7a such as fluorescent dyes or reflectors such as short glass fibers scattered therein, and has a document reading surface 8a (CLEA) scattered therein.
The illumination surface 7C is formed in an arbitrary shape (for example, an arc shape) toward the upper surface of the R-type optical fiber array 2a.

If this light guide 7 is used, light that conventionally was merely attenuated by repeated absorption and diffuse reflection in the image sensor unit constituent materials around the LED array without entering the document reading surface 8a, or The light 91 emitted from the light emitting surface 6C of the LED array 6a in a direction other than the direction of the original reading surface 8a, which is lost light such as stray light leaking outside, is removed.
The light receiving surface 7d of the PC light guide 7 receives the light and takes it into the PC light guide 7. Further, a large number of phosphors 7a such as fluorescent dyes or other reflectors such as short glass fibers, magnesium carbonate, carnoum carbonate, etc., scattered in an arbitrary content inside the light guide 7 cause a chain of fluorescence and This causes diffuse reflection and reflected light guiding in various directions at the interface of the PC light guide 7.

Therefore, these reflected guided lights are irradiated onto the original reading surface 8a together with the light 9h emitted from the light emitting surface 6c of the LED array 6a in the direction of the original reading surface 8a, which has been effective as conventional illumination light from the illumination surface 7C. Ru.

Further, since the light guiding as described above is performed not only in the sub-scanning direction 1a but also in the main-scanning direction 1b, the illumination surface 7
The intensity of the illumination light emitted from C is made uniform in the main scanning direction 1b.

The reason for this uniformity will be explained in detail using FIG. 3.4.

In FIG. 3, light emitted from arbitrary LEDs 20, 2+ of the LED array 6a lined up in the main scanning direction 1b enters the light receiving surface 7d of the PC light guide 7. Among these, the incident angle of the light is small near the upper part of the LED 70.71, so the reflected light 40.41 is relatively weak (shown by the broken line), but it enters here and is taken into the PC light guide 7. The light on the side is relatively strong (shown by the solid line).

In addition, near the LED gap 72, the incident angle is large, so the reflected light 40.41 is relatively strong (shown by the solid line), so the light that enters from here and is taken into the PC light guide 7 is comparatively Weak target (illustrated by dashed line).

In the above, when the phosphor 7a and the reflector are not powdered inside the PC light guide 7, near the LED upper part 70,
Light with a small incident angle emitted from LED20 and LED2+
Light with a large incident angle is emitted from the light receiving surface 7d, and while being refracted by the light receiving surface 7d, relatively strong light and relatively weak light overlap and reach the illumination surface 7c.

Similarly, near the LED upper part 71, light emitted from the LED 21 with a small incident angle and light emitted from the LED 20 with a large incident angle enter the PC light guide 7 while being refracted at the light receiving surface 7d.
The relatively strong light taken in and the relatively weak light overlap and reach the illumination surface 7c.

However, near the upper part 72 between the LEDs, light with a large incident angle emitted from the LED 20 and light with a large incident angle emitted from the LED 21 enter the area, and while being refracted by the light receiving surface 7d, the light is relatively weak. The light overlaps and reaches the illumination surface 7C.

From this, KI7071 above the LED and the upper part 7 between the LEDs
A large difference in illuminance occurs between the illuminances of the two illumination surfaces 7c.

As a result of the above, since the illumination surface is illuminated from the illumination surface 7c in the main scanning direction 1b, large variations are likely to occur on the document reading surface 8a.

However, by scattering a large number of phosphors 7a and reflectors inside the PC light guide 7, light with a small or large incident angle emitted from the LED 20. Most of the relatively strong light or relatively weak light taken into the light guide 7 is caused by a large number of phosphors 7 such as fluorescent dyes scattered inside the PC light guide 7 in arbitrary amounts.
a, or a reflector such as short glass fiber, magnesium carbonate, calcium carbonate, etc., causes continuous fluorescence and diffuse reflection in the main scanning direction 1b and sub-scanning direction 1a, and various directions at the interface of the PC light guide 7. In other words, each light is diffused in a wide range inside the PC light guide 7 with its own intensity, and overlapped in a complicated manner, so that the light is reflected in the main scanning direction. At 1b, the illumination light reaching the illumination surface C is averaged or made uniform.

This makes the illuminance of the illumination surface 7C of the LED upper part 70, 71 and the inter-LED upper part 72 almost uniform.

Figure 4 shows the light 30i emitted from the LEDs 20 and 21 in Figure 3.
, 30j, the state of the diffusion is simplified for convenience. Light 30i, 3 emitted from LEDs 20, 21
0j is the illumination surface 7 when there is no phosphor 7a or reflector.
Point A on c reaches point 0.

However, if the phosphor 7a or reflector is in the optical path,
When the fluorescent material 7a or the reflector hits the fluorescent material 7a and causes the fluorescent light to be emitted or is diffusely reflected, a portion of the fluorescent light and the diffusely reflected light are respectively illuminated on the illumination surface 7.
It can be seen that it reaches points B and D on C.

As described above, by irradiating uniform illumination light from the illumination surface 7c in the main scanning direction 1b, the document reading surface 8a
Significantly reduces variations in illuminance.

Therefore, it is possible to increase the illuminance of the document reading surface 8a, reduce variations in the illuminance of the document reading surface 8a due to ripples of the LED array 6a, and further reduce the number of LEDs 6d in the LED array 6a.

This makes it possible to downsize the LED array 6a, reduce the number of cylindrical lenses, shorten the distance between the LED array 6a and the original reading surface 8a, and downsize the illumination structure of the original reading surface 8a.
Realize thinness.

(Structure and function of light shielding/reflector) The light shielding/reflector 7b is coated on the end surface of the PC light guide 7 other than the illumination surface 7c and on the back surface 7e of the PC light guide 7 opposite to the light receiving surface 7d. or placed.

With the above structure, as shown in FIG. 5, the loss of stray light leaking from the end surface of the light guide 7 and the surface (back surface) 7e opposite to the light receiving surface 7d is greater than when there is no light shielding/reflector. light 9
d is completely eliminated, the light is returned to the PC light guide 7, and guided to the illumination surface 7C, thereby realizing an increase in illuminance on the document reading surface 8a and a reduction in illuminance variation.

Furthermore, this structure can block stray light such as direct light and indirect light from the LED array 6a from directly entering the light receiving element 4a.

(Structure and operation of the light-receiving surface of the light guide 7) As shown in FIG. A circular arc-shaped light-receiving surface 7f is formed with the light-emitting source 6b orthogonal to the light-emitting surface 6b as the center.

With the above structure, it is possible to reduce the loss of light due to reflection of the light 9 on the light receiving surfaces 7d and 7F, and to efficiently introduce the tip 9j into the PC light guide 7.

Further, as shown in FIG. 6, a surface (back surface) 7e opposite to the light receiving surfaces 7d and 7f has a predetermined angle θ with respect to the light receiving surfaces 7d and 7f.

With this angle θ, the light has a reflection angle, and the light receiving surface 7
The relatively strong main light 9j that is introduced into the PC light guide 7 from d and 7f and incident along the extension line of the LED light emitting source 6b of the LED array 6a leaks out of the PC light guide 7. , reduce the amount of transmitted lost light 9d, or
The tip 9j is laterally reflected and the light is efficiently guided to the illumination surface 7C, thereby increasing the illuminance of the document reading surface 8a and reducing the variation in illuminance.

Furthermore, as shown in FIG. 7, the light receiving surface of the PC light guide 7 has L
Relatively strong main light 9a that enters along a straight line connecting the light emitting source 6b of the ED array 6a and the document reading surface center 8, and connects any part of the light emitting surface 6C of the LED array 6a and the document reading surface setter 8. An arcuate light-receiving surface 7g centered at the document reading surface center 8 is formed, which is perpendicular to the main light 9b incident along a group of straight lines.

Further, the light receiving surface 7g and the main light 9a mentioned above.

9b and the light 9 that goes straight to the guided document reading surface center 8.
An illumination surface 7h opposite to the light-receiving surface 7g is formed in an arc shape centered on the document reading surface center 8 orthogonal to k.

With the above structure, reflection of the main light beams 9a and 9b at the light receiving surface 7g and the opposite surface (back surface) 7h is reduced, and the main light beams 9a and 9b can be efficiently transmitted to the document reading surface 8a.
a, 9b are irradiated to increase the illuminance of the document reading surface 8a.

(Structure and function of base plate 2b) Then, on the base plate 2b of CLEAR type FAP2, LE
Main light 9a incident along a group of straight lines connecting any part of the light emitting surface 6C of the D array 6a and the document reading surface center 8;
9b and the light 9 that goes straight to the guided document reading surface center 8.
It has an arc-shaped surface 2e centered on the document reading surface center 8, which is perpendicular to the direction k.

With the above structure, reflection of the main lights 9a, 9b and light 9 on the surface of the base glass material 2b is reduced, and the main lights 9a, 9b, and 9 are efficiently transmitted to the document reading surface 8a.
k is irradiated to realize an increase in illumination of the document reading surface 8a.

[Second Embodiment] FIG. 8 is a sectional view of an image sensor showing a second embodiment of the present invention.

In this embodiment, the base glass material 2 of the CLEAR type FAP 2 is used in which the FAPs 2 and 3 are used to guide the reflected light from the document reading surface 8a as the image sensor reading light 9.
b is deleted.

With the above structure, attenuation of the illumination light 9C due to reflection and absorption by the base glass material 2b is eliminated, and the illuminance of the document reading surface 8a is increased.

[Third Embodiment] A third embodiment according to the present invention will be described in detail with reference to FIG. 9.10.

FIG. 9 is a sectional view of a contact type image sensor according to a third embodiment of the present invention, and FIG. 10 is a sectional view similarly showing the state of scattering of irradiated light.

As shown in the figure, in this embodiment, the PC light guide 7 has a slit hole of an arbitrary width along a group of straight lines connecting the light emitting source 6b of the LED array 6a and any part of the light emitting surface 6C to the document reading surface 8a. 10 is formed on the illumination surface 7c of the document reading surface 8a. The other configurations are the same as those of the first embodiment.

In the above configuration, relatively strong main light 9a, 9 enters approximately along a straight line connecting the light emitting source 6b of the LED array 6a and any part of the light emitting surface 6C to the document reading surface 8a.
b, 9h eliminate attenuation due to reflection, absorption, etc. at the PC light guide 7, and increase the illuminance of the document reading surface 8a.

[Fourth Embodiment] Figure 1+ is a sectional view of an image sensor according to a fourth embodiment of the present invention.

In this embodiment, the light guide 7 has a light receiving surface 7d on its inner surface that is flat on all three sides, and the light receiving surface 7d of the light guide 7 is formed on a straight line connecting the document irradiation surface 88 and the light emitting source of the LED array 6a as a light emitting body. , a slit IO is formed.

Further, the end surface of the base plate 2b of the CLEAR type optical fiber array plate 2 is a plane perpendicular to the straight line connecting the light emitting source of the LED array 6a and the document irradiation surface.

In the above configuration, the relatively strong main light 9a that enters the document reading surface 8a from the light emitting source 6b of the LED array 6a is
There is no attenuation due to reflection or absorption on the light guide 7, and since less light is linearly incident and reflected on the base plate 2b, it is possible to increase the illuminance on the document reading surface 8a.

[Fifth Embodiment] FIG. 12 is a sectional view of an image sensor showing a fifth embodiment of the present invention.

In this embodiment, the light guide 7 includes a convex lens-shaped illumination portion 11.
was formed.

Further, the end surface of the base plate 2b is formed flat and spaced apart from the lens II.

With the above structure, the light 9g incident on the illumination portion II of the convex lens by direct light or reflected light from the LED array 6a is focused on the document reading surface 8a, thereby realizing an increase in the illuminance of the document reading surface 8a.

[Sixth Embodiment] FIG. 13 is a sectional view of an image sensor showing a sixth embodiment of the present invention.

In this embodiment, in an FAP 2.3 that guides the reflected light from the original reading surface 8a as the image sensor reading light 9, the supporting material of the CLEAR type optical fiber array 2a of the CLEAR type FAP 2 and the transparent original supporting material are used. The base plate 2b has a flat surface 2d that is perpendicular to the relatively main light 9a incident along the straight line connecting the light emitting source 6b of the LED array 6a and the document reading surface center 8. . The other configurations are the same as those of the first embodiment.

With the above structure, the base plate 2b of the main light 9a is
This reduces reflection on the surface of the document reading surface 8a and efficiently increases the illuminance of the document reading surface 8a.

It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

For example, the light guide is not limited to containing a phosphor or a reflector, and is not limited to being made of PC, as long as it is made of a material that can efficiently and uniformly irradiate light received on the surface from the end surface.

<Effects of the Invention> As is clear from the above description, according to claim 1 of the present invention, there is provided a guide capable of efficiently guiding light received on a surface to an end face (cross section) I and irradiating the light from the end face. Since the light emitter is covered with a light body, lost light such as stray light can be efficiently guided to the illumination surface, which is the end face of the light guide, and the illuminance of the document reading surface can be increased.

Moreover, this makes it possible to improve the S/N ratio of the image sensor.

Furthermore, by reflecting and guiding light in various directions at the interface of the light guide, the intensity of the illumination light emitted from the illumination surface is made uniform in the main scanning direction, and the ripples of the light emitter can cause the document reading surface to be distorted. Reduces illuminance variations, and furthermore, L as a light emitter
It is possible to reduce the number of LEDs in the ED array.

In addition, by maximizing the above effects, we can further reduce the size of light emitters such as LED arrays, reduce the number of cylinders (rod lenses) used to collect the light of the light emitters, and reduce the distance between the light emitters and the document reading surface. The illumination system for the document reading surface can be made smaller and thinner by shortening the time.

In addition, in claim 2, by providing a reflective material on the outer surface of the light guide such as a PC, it is possible to eliminate lost light leaking or passing through the surface, and return the light to the light guide, or , by reflecting the light laterally and efficiently guiding it to the illumination surface, increasing the illuminance of the document reading surface.
It is possible to reduce variations in illuminance on the document reading surface due to reflected light in various directions.

Furthermore, by providing the reflective material, it is possible to block stray light from the LED array from directly entering the image sensor portion.

According to claim 3, in the light guide, a flat light-receiving surface orthogonal to relatively strong and main light incident along an extension line of a light emitting source of a light emitting body such as an LED array; Since it forms an arc-shaped light-receiving surface centered on the light emitting source that is perpendicular to the It is possible to capture the light and guide it to the illumination surface to increase the illumination on the side opposite to the document reading surface.

Furthermore, according to claim 4, since the light-receiving surface is formed at a predetermined angle with respect to the outer surface thereof, the light has a reflection angle depending on the angle, and the light taken into the light guide is reflected by the light-receiving surface. Reduces the amount of light that leaks out of the light body and the amount of lost light that passes through it,
Alternatively, it is possible to efficiently guide light to the illumination surface, increase the brightness of the document reading surface, and reduce variations in illuminance on the document reading surface due to reflected light guided in various directions.

According to claim 5, in the light guide, a relatively strong main light incident along a straight line connecting the light emitting source of the light emitting body and the center of the document reading surface, and an arbitrary light on the light emitting surface of the light emitting body. An arc-shaped light-receiving surface is formed with the center of the document-reading surface perpendicular to the main light incident along a group of straight lines connecting the center of the document-reading surface and the center of the document-reading surface. Since it forms an arc-shaped illumination surface centered on the document reading center that is perpendicular to the light and the guided light that goes straight to the center of the document reading surface, the main light receiving surface mentioned above, It is also possible to reduce reflection on the illumination surface, which is the opposite surface (back surface), and efficiently irradiate the document reading surface with the light, thereby increasing the illuminance of the document reading surface.

According to claim 6, in the light guide, a slit hole of an arbitrary width is formed in the document reading surface along a group of straight lines connecting the light emitting source of the light emitting body and any part of the light emitting surface, and the document reading surface. By forming it on the illumination surface, it is possible to eliminate the attenuation of the relatively strong main light incident almost along the above-mentioned straight line due to reflection and absorption by the PC light guide 7, thereby increasing the illuminance of the document reading surface. can.

According to claim 7, by forming a convex lens-shaped illumination surface portion on the light guide, direct light or reflected light from the light emitting body can be used to illuminate the original. By focusing the light on the reading surface, it is possible to increase the illuminance of the document reading surface.

According to claim 8, in a device using an optical fiber array plate that guides reflected light from a document reading surface to a light receiving element, the base plate of the optical fiber array plate is provided with a light emitting source of a light emitting body and a light emitting source of the document reading surface. It forms a flat surface perpendicular to the incident light along a straight line connecting the centers, and according to claim 9, a straight line connecting any part of the light emitting surface of the light emitting body and the center of the document reading surface. The base plate has an arc-shaped surface centered on the center of the document reading surface that is perpendicular to the main light incident along the group and the guided light that goes straight to the center of the document reading surface. It is possible to reduce the reflection of incident light on the surface of the base plate, efficiently irradiate the original reading surface with the light, and increase the illuminance of the original reading surface.

In addition, by forming the above-mentioned surface, it is not necessary to take into consideration the deviation of the optical axis of the light due to the refractive index of the base plate in correspondence with the base plate thickness. It has an excellent effect of not being affected.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view of a contact type image sensor unit showing a first embodiment of the present invention, and FIG. 2 is an A-A in FIG. 1.
Figure 3 is a cross-sectional view and illuminance graph in the main scanning direction, Figure 4 is a simplified cross-sectional view of the main irradiation light in the main scanning direction, and Figure 5 is a light shielding/reflecting material according to the present invention. Figure 6 is a cross-sectional view showing that the light-receiving surface of the light guide has a predetermined angle, and Figure 7 (a) shows the light-receiving surface of the light guide and the illumination. 7(b) is a sectional view showing the scattering state in the light guide; FIG. 8 is a sectional view of an image sensor showing the second embodiment of the present invention. , FIG. 9 is a sectional view of a contact type image sensor showing a third embodiment of the present invention, FIG. 12 is a sectional view of an image sensor showing a fifth embodiment of the present invention; FIG. 13 is a sectional view of an image sensor showing a sixth embodiment of the present invention; FIG. 14 is a cross-sectional view of a conventional image sensor, No. 15
The figure is also a sectional view in the main scanning direction, and FIG. 16 is a configuration diagram of a facunmill device using an image sensor. l Original, Ia sub-scanning direction, lb main scanning direction, lc original feeding direction, 2: CLEAR type FAP, 2a CLEAR type optical fiber array, 2 b, 2 c: base glass material, 3: E M A type FAP, 3a: EMA type optical fiber array, 3b Heath glass material, 4, image sensor board, 4a image sensor part, 5: housing, 6
: LED array board, 6a: LED array, 6b light source, 6e light emitting surface, 6d, 6e, 6f: LED, 7 light guide, 7g light receiver, 7b, light shielding/reflecting material, 7c illumination surface, 7
d, 7f, 7g light receiving surface, 7e7h, outer surface, 8: document reading surface center, 8a document reading surface, 9 image sensor reading light, 9 a, 9 b, 9 e to 9Q, light, 9c light guided Illumination light, 9d, lost light such as stray light, lO Nislit tip, 11: convex lens-shaped illumination part, 12, housing, 1
2a Light shielding part, 2021: LED, 30 Lighting surface, 30
a-30j light, 31a to 31f: light, 32: relatively strong light, 33. Relatively weak light, 34. Relatively strong reflected light, 3
5: Relatively weak reflected light, 40.41・Reflected light, 50.5
2,70 72: LED upper part, 50a, 51a 52a
, 70a71a, 72a: Illuminance, 51.71: LED
Upper part 373: Illuminance variation graph, 54: Illuminance difference, 74 Illuminance difference. Applicant Noyab Co., Ltd.

Claims (1)

[Claims] 1. A contact image sensor including a light emitter that illuminates a document to be read and a light receiving element that converts light reflected from the document into an electrical signal, wherein the light emitter emits the light. The illumination surface is covered with a light guide made of a material that can efficiently and uniformly illuminate the document from the illumination surface, and the light guide guides the lost light from the light emitter to illuminate the document reading surface. Optical system structure of a contact type image sensor characterized by irradiation. 2. In the contact type image sensor according to claim 1, a light shielding/reflecting material is provided on an end face other than the illumination surface of the light guide according to claim 1, and further between the light guide and the light receiving element, a light shielding/reflecting material is provided between the light guide and the light receiving element. An optical system structure of a contact type image sensor, characterized in that a light shielding/reflecting material is provided to prevent the incidence of stray light. 3. The light guide according to claim 1 has at least a flat light-receiving surface orthogonal to the light on an extension of the light emitting source of the light emitter according to claim 1, or a light receiving surface centered on the light emitting source orthogonal to the light. An optical system structure of a contact image sensor characterized by an arc-shaped light receiving surface. 4. In the optical system structure of the contact type image sensor according to claim 1, the light receiving surface of the light guide according to claim 1 is configured to have a predetermined angle with respect to the outer surface thereof. An optical system structure of a contact type image sensor, characterized in that the light from the light emitter according to item 1 is reflected by the outer surface to reduce the amount of lost light transmitted from the outer surface. 5. The light guide according to claim 1 transmits light on a straight line connecting the light emitting source of the light emitter and the center of the document reading surface, and connects any part of the light emitting surface of the light emitter to the center of the document reading surface. An arcuate light-receiving surface is formed centered on the center of the document reading surface that is perpendicular to the light on the straight line group, and the light from the light-receiving surface and the guided light travel straight to the center of the document reading surface. By forming an arc-shaped illumination surface centered on the center of the document reading surface that is perpendicular to the light, reflection of the light from the light emitter on the light receiving surface and the illumination surface is reduced. Optical system structure of a contact-type image sensor. 6. In the light guide according to claim 1, the slit holes are formed along the group of straight lines connecting the light emitting source of the light emitting body and any part of the light emitting surface and the document reading surface, so that the light guide body can be provided with a light guide along the group of straight lines. An optical system structure for a contact image sensor characterized by reducing attenuation of incident light due to reflection, absorption, etc. on a light guide. 7. An optical system structure for a contact image sensor, characterized in that the light guide according to claim 1 is formed with a convex lens-shaped illumination surface portion to condense light incident on the illumination portion. 8. The contact type image sensor according to claim 1, further comprising a fiber array plate that guides reflected light from the document reading surface to the light receiving element according to claim 1, and a base plate of the fiber array plate has a base plate having a base plate according to claim 1. A contact image sensor characterized in that reflection on the surface of the base plate is reduced by forming a surface perpendicular to light on a straight line connecting the light emitting source of the light emitting body according to 1 and the center of the document reading surface. optical system structure. 9. The base plate of the fiber array plate according to claim 8 is provided with a light beam centered at the center of the document reading surface that is perpendicular to the light on the group of straight lines connecting any part of the light emitting surface of the light emitting body and the center of the document reading surface. An optical system structure of a contact type image sensor, characterized in that reflection on the surface of the base plate is reduced by forming an arcuate surface.