JP2002125093A - Optical reading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical reading device capable of improving the floating characteristics of an original, and making picture reading characteristics excellent. SOLUTION: A diffuser panel 15 is arranged so that a light emitting part 12 can be almost covered. Thus, the directivity of a light can be weakened, and the level of darkening can be extremely reduced against the floating part of the original 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical reader used for an information terminal such as a facsimile, a copying machine, an electronic filing apparatus, a word processor, and a computer.

[0002]

2. Description of the Related Art As a conventional optical reader, there is a flatbed scanner. Flatbed scanners include a CCD image sensor system and a contact image sensor system depending on the type of image sensor, and the contact image sensor system is advantageous in terms of miniaturization of the apparatus.

[0003] The reading principle of a conventional contact image sensor type flatbed scanner will be described with reference to FIG. In FIG. 11, the contact image sensor 101 arranged below the document 104 is not visible.
For convenience of explanation, it is shown by a solid line. In the figure, 104
A contact image sensor 101 for reading information described on the document 104,
Reference numeral 2 denotes a document 104 provided in the contact image sensor 101.
A light emitting unit 103 emits light in the direction of, and a light receiving unit 103 receives light signals emitted by the light emitting unit 102 and reflected by the document 104.

[0004] The operation of the conventional optical reading device configured as described above will be described below.

The contact image sensor 101 comprises a light emitting unit 102 and a light receiving unit 103 which emit light linearly.
2 is applied to the original 104, the reflected light is received by the light receiving unit 103, and characters and images of the original are read based on the amount of received light. An LED is used as a light source of the light emitting unit 102. An LED array system in which a plurality of LEDs are arranged in an array to emit light linearly, and only one LED light source guides LED light with a light guide. There is a light guide system that emits light linearly. The light guide method can reduce current consumption because it has only one LED as compared with the LED array method. When colorizing the sensor, three color LED light sources are required. However, in order to realize colorization by the LED array method, the number of LEDs becomes extremely large, and it is difficult to reduce the size of the sensor. The light guide method is advantageous for the above.

[0006]

However, in the above-mentioned conventional configuration, there is a problem that the light guide system is weak against the floating of the original. That is, when the original is shifted from the original reading position, the amount of light incident on the light receiving unit 103 via the original 104 is significantly reduced, and the image read from the original 104 becomes black at the floating portion of the original 104. The difference in the floating characteristics is caused by the difference in directivity of the light source (light emitting unit 102). Since the light guide system has a higher directivity of the light source than the LED array system, even if the original slightly deviates from the original reading position, the amount of light returning to the light receiving unit is significantly reduced.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide an optical reading apparatus that is resistant to floating of a document.

[0008]

In order to achieve the above object, an optical reading apparatus according to the present invention irradiates light to a portion to be read, and reads information of the portion to be read by reflected light. An apparatus, comprising: a light emitting unit that emits light; a light receiving unit that receives light emitted from the light emitting unit and reflected by the read unit; and a light diffusing member that diffuses the light of the light emitting unit. It is.

It is another object of the present invention to provide an optical reading apparatus which is resistant to the floating of a document.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to the first, second and third aspects of the present invention is an optical reading apparatus for irradiating light to a portion to be read and reading information of the portion to be read by reflected light. A light-emitting unit that emits light, a light-receiving unit that receives light emitted from the light-emitting unit and reflected by the read unit, and a light-diffusing member that diffuses the light of the light-emitting unit, With such a configuration, the light from the light emitting unit is diffused by the light diffusing member, so that the directivity of the light is weakened and the degree of blackening of the floating portion of the document can be significantly reduced.

According to the fourth, fifth, and sixth aspects of the present invention, there is provided an optical reading apparatus for irradiating light to a read portion and reading information of the read portion by reflected light thereof. A light-emitting unit that emits light, and a light-receiving unit that receives light reflected from the read unit that emits light from the light-emitting unit,
A light diffusing member for diffusing the light of the light emitting portion, wherein the light transmittance of the light diffusing member is changed according to a light emitting position. With such a configuration, light from the light emitting portion is diffused by the light diffusing member. As a result, the directivity of light is weakened, the degree of blackening of the floating portion of the document can be significantly reduced, and the light transmittance of the light diffusing member is changed depending on the light emitting position. Can be improved to uniform light output characteristics.

According to a seventh aspect of the present invention, there is provided an optical reading apparatus for irradiating light to a read portion and reading information of the read portion by reflected light,
A light emitting unit that emits light, a light guide that guides light from the light emitting unit, and a light diffusing member that diffuses light of the light emitting unit, wherein the light guide faces a light emitting surface The position is provided with a reflecting portion that reflects light. With such a configuration, light can be efficiently emitted from the light guide without waste by reflecting light.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a perspective view showing the appearance of an optical reader according to an embodiment of the present invention, and FIG.
(A) is A of the image sensor unit 18 in FIG.
2A is a cross-sectional view, and FIG. 2B is a side view in which a part is cut away at a BB portion in FIG. In the figure,
Reference numeral 11 denotes a light guide that is arranged in the longitudinal direction in the image sensor unit 18 and guides an optical signal from a light emitting unit 12 described later over the entire area, and is made of a material such as glass or plastic. Reference numeral 12 denotes a light emitting unit that emits an optical signal, and is located at an end of the light guide 11. Reference numeral 13 denotes a rod lens group for condensing an optical signal reflected by the document from the light guide 11, and reference numeral 14 denotes a light receiving element for detecting light condensed through the rod lens group 13. Here, the light guide 11, the rod lens group 13, and the light receiving element 14 are all fixed to the frame 10. Further, a diffusion plate 15 made of a sheet-like plastic and mixed with a light diffusion material is provided so as to substantially cover the light guide 11. One end of the diffusion plate 15 is the frame 1
It is fixed to 0. The document 17 is placed on a transparent glass body 16 provided above the image sensor unit 18.

The operation of the embodiment constructed as described above will be described with reference to FIGS. 1 and 2.

The light emitted from the light emitting section 12 is the light guide 1
1, light is emitted outward while being guided in the longitudinal direction. At this time, the outward light is reflected by the original 17 placed on the transparent glass body 16 via the diffusion plate 15, and the reflected light enters the light receiving element unit 14 through the rod lens group 13. Therefore, the light reflected on the original 17 is transmitted to the diffuser 1
As a result of the scattering effect by 5, the directivity of light is weakened (directivity is widened), and the degree of blackening of the floating portion of the document 17 can be significantly reduced.

Incidentally, the diffusion plate 15 of the present embodiment is similar to that of FIG.
Although the cross-sectional shape is substantially L-shaped as shown in FIG. 3A, the substantially same operation and effect can be obtained even with the substantially flat diffusing plate 15a as shown in FIG.

As described above, according to the present embodiment, the light emitted from the light emitting section 12 is such that the light having undergone the scattering effect via the diffusion plate 15 hits the original 17 placed on the transparent glass body 16. As a result, the directivity of light is weakened, and the degree of blackening of the floating portion of the document can be significantly reduced.

Although this embodiment has been described for the case of the light guide type, the same can be applied to the case of the LED array type. Although the LED array system has better characteristics with respect to the floating of the document than the light guide system as described in the conventional example, a diffusion plate may be attached so as to cover the LED array in order to further improve the characteristics.

(Embodiment 2) Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 4 shows a diffuser plate 1 in which the shape of the end face is substantially arcuate and has a cut in the longitudinal direction.
FIG. 5 is a perspective view showing an arrangement relationship before mounting the light guide 5b to the image sensor unit 18, and FIG. 5 shows a state in which the diffusion plate 15-2 is mounted in a pressure contact state over substantially half the circumference of the light guide 11 or more. FIG.

When the light guide 11 has a reinforcing rib or the like (not shown), for example, a rectangular cutout 15c (two places in this example) is provided as shown in FIG. It is also possible to mount the diffuser plate 15b in this manner, so that the range of the pressure contact can be widened, the mounting can be performed in a more stable state, and the diffusion plate 15b can be positioned in the longitudinal direction.

Since the light guide 11 is covered with the diffusion plate 15b, the same operation and effect as those of the first embodiment can be obtained.

In this embodiment, an arc shape is described, but other shapes, such as a rectangle, can be formed in a shape conforming to the shape.

As described above, according to the present embodiment, the light emitted from the light emitting section 12 is such that the light having undergone the scattering effect via the diffusion plate 15 hits the original 17 placed on the transparent glass body 16. As a result, the directivity of light is weakened, and the degree of blackening of the floating portion of the document can be significantly reduced. Although the present embodiment has been described for the case of the light guide type, the same can be applied to the case of the LED array type. Although the LED array system has better characteristics with respect to the floating of the document than the light guide system as described in the conventional example, a diffusion plate may be attached so as to cover the LED array in order to further improve the characteristics.

(Embodiment 3) Next, a third embodiment of the present invention will be described with reference to FIG. Light guide 1 of the present embodiment
Numeral 9 is made of a material such as glass or plastic, and at least the surface emitting light to the outside has a large surface roughness by means of chemical treatment (for example, erosion treatment with an alkaline solution) or mechanical processing (for example, sandblasting). It is in a state where it has been done. Therefore, the light emitted from the light guide 19 is subjected to the scattering effect, and has exactly the same operation and effect as in the first and second embodiments.

(Embodiment 4) Next, a fourth embodiment of the present invention will be described with reference to FIGS. 7, 8, and 9. FIG. 7 is a cross-sectional view of the image sensor unit 18 showing the configuration of the present embodiment, FIG. 8 is a plan view of the light guide 19, FIG. 9A is a light output characteristic before improvement, and FIG. 5 shows light output characteristics improved by the embodiment. In FIG. 9, the horizontal axis indicates the position in the longitudinal direction of the light guide 19, where the left side in the figure indicates the near end to the light emitting unit 12 and the right side indicates the far end to the light emitting unit 12. The vertical axis represents the light output at that position. In FIG. 7, 1
Reference numeral 9 denotes a light guide, the surface of which is formed into a fine uneven portion 15c by a method such as chemical polishing, and the surface roughness is changed in the longitudinal direction of the light guide 19 as shown in FIG. The surface roughness decreases as the distance from the light emitting unit 12 decreases, and increases as the distance from the light emitting unit 12 increases.

The operation of the present apparatus configured as described above will be described. The reduction of the degree to which the unevenness of the light guide becomes black with respect to the floating portion of the document is the same as in the third embodiment. And the description is omitted.

The light intensity emitted from the light guide 19 on the side closer to the light emitting unit 12 and the light guide 1 at a position away from the light emitting unit 12
9 has a difference in light intensity, which greatly affects the light output characteristics. When the uneven shape is uniform in the longitudinal direction of the light guide 19, the light output characteristic becomes uneven in the longitudinal direction as shown in FIG. It is desirable that the light output characteristics be as uniform as possible. For this reason, in the present embodiment, the surface roughness of the uneven portion 15c in the longitudinal direction of the light guide 19 is locally changed to reduce the light diffusion degree in the longitudinal direction. Adjust in the direction. The surface roughness is adjusted by adjusting the height difference between peaks and valleys and the gap between the peaks by applying fine irregularities to the surface by chemical polishing, etc., and correcting the light output characteristics to be uniform. This can be realized by forming a local processing pattern that is applied to and adjusted on the substrate.

As described above, according to the present embodiment, the unevenness of the light guide 19 weakens the directivity of light, and the degree of blackening of the floating portion of the document can be significantly reduced. The uneven light output characteristics of the image sensor unit 18 can be improved to uniform light output characteristics.

Although the present embodiment has been described with reference to the case where the light characteristics are improved by changing the uneven shape of the light guide 19, the same can be realized with a diffusion plate. That is, by changing the light transmittance of the diffusion plate in accordance with the light emitting position, uniform light output characteristics can be obtained.

(Embodiment 5) Next, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 10 is a sectional view of the image sensor unit 18 showing the configuration of the present embodiment. In FIG. 10, it has been described in the third embodiment that the fine irregularities of the light guide 19 weaken the directivity of light and significantly reduce the degree of blackening of a floating portion of a document. It is on the street.

Here, by subjecting the bottom of the light guide 19 facing the uneven portion of the light guide 19 to a process of reflecting light such as a mirror-finished finish 20, the light emitted from the light emitting section 12 is guided. The light is emitted outward while being guided in the longitudinal direction through the light body 19, but light to the mirror finish 20 side of the light guide 19 at the bottom passes through the light guide 19 by the mirror finish 20. The light is efficiently diffused from the concave-convex-shaped portion 15 c, and the light hits the original 17 placed on the transparent glass body 16, and the reflected light enters the light receiving element portion 14 through the rod lens group 13.

In this embodiment, by providing the mirror-finished surface 20 at the bottom of the uneven portion in the longitudinal direction of the light guide, light can be guided without waste and the image sensor unit 18 with high efficiency can be provided. Here, the bottom of the light guide 19 of the present embodiment has a mirror-finished surface, but it can also be realized by means effective for reflecting light, for example, painting with white.

[0034]

As described above, according to the present invention, by providing the light diffusing member so as to substantially cover the illuminant, an excellent effect that the degree of blackening of the floating portion of the document can be remarkably reduced can be obtained.

Further, according to the present invention, by providing a light diffusing member so as to substantially cover the light emitting body and changing the light transmittance of the light diffusing member depending on the light emitting position, the degree of blackening of the floating portion of the document can be remarkably reduced. At the same time, an excellent effect of obtaining uniform and stable light output characteristics can be obtained.

Further, according to the present invention, by providing the light reflecting portion at the bottom of the light guide, the degree of blackening of the floating portion of the document can be significantly reduced, and at the same time, the light from the light guide can be efficiently guided. Is obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of an image sensor unit according to Embodiment 1 of the present invention.

FIG. 2A is a cross-sectional view of the image sensor unit according to the embodiment. FIG. 2B is a plan view of the image sensor unit according to the embodiment with a part cut away.

FIG. 3 is a sectional view showing another mode in the embodiment.

FIG. 4 is a perspective view showing an arrangement relationship of an image sensor unit according to a second embodiment of the present invention.

FIG. 5 is a sectional view of the image sensor unit according to the embodiment;

FIG. 6 is a cross-sectional view of an image sensor unit according to Embodiment 3 of the present invention.

FIG. 7 is a cross-sectional view of an image sensor unit according to Embodiment 4 of the present invention.

FIG. 8 is a plan view of the light guide according to the embodiment.

FIG. 9 is a view for explaining an improvement in light output characteristics in the embodiment.

FIG. 10 is a sectional view of an image sensor unit according to a fifth embodiment of the present invention.

FIG. 11 is a diagram illustrating a reading principle of a conventional contact image sensor type flatbed scanner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Frame 11 Light guide 12 Light emitting part 13 Rod lens group 14 Light receiving element part 15 Diffusion plate 16 Transparent glass body 17 Document 18 Image sensor unit

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) G06T 1/00 420 G06T 1/00 420C 5C072 420F H04N 1/04 101 H04N 1/04 101 1/19 102 (72) Invention Person Yukihiro Kameda 1006 Kadoma, Kazuma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Toshiaki Koga 1006 Kadoma, Kazuma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. EA51 GA04 GA09 2H109 AA02 AA12 AA51 AA72 AA94 DA12 5B047 AA01 BB02 BC11 BC12 CA19 5C051 AA01 DA03 DB01 DB29 DC04 DC05 FA01 5C072 AA01 BA13 BA15 CA02 CA15 DA16 DA21 DA25 DA30 EA07 XA01

Claims (7)

[Claims] An optical reading device that irradiates light to a read portion and reads information of the read portion by reflected light thereof, wherein the light emitting portion emits light, and the light emitting portion emits light from the light emitting portion. An optical reading device, comprising: a light receiving portion that receives light reflected by a portion to be read; and a light diffusion member that diffuses light of the light emitting portion. 2. An optical reading device which irradiates light to a read portion and reads information of the read portion by reflected light thereof, comprising: a light emitting portion for emitting light; and a light from the light emitting portion. A light guide that guides the light; a rod lens group that receives light emitted from the light emitting unit and reflected by the read unit; a light receiving element that receives light from the rod lens group; and diffuses light from the light emitting unit. Light diffusion member,
The optical reading device, wherein the light diffusion member is provided so as to substantially cover the light guide. 3. The optical reader according to claim 1, wherein the surface of the light guide has a fine uneven shape. 4. An optical reading device that irradiates light to a read portion and reads information of the read portion by reflected light thereof, wherein the light emitting portion emits light, and the light emitting portion emits light from the light emitting portion. An optical device comprising: a light receiving unit that receives light reflected by a read unit; and a light diffusion member that diffuses light from the light emitting unit, wherein light transmittance of the light diffusion member is changed according to a light emission position. Expression reader. 5. An optical reading device that irradiates light to a read portion and reads information of the read portion by reflected light thereof, wherein the light emitting portion emits light, and the light from the light emitting portion emits light. A light guide that guides the light, a rod lens group that receives light emitted from the light emitting unit and reflects the light to be read, a light receiving element that receives light from the rod lens group, and a light guide that substantially covers the light guide. An optical reader comprising: a diffusion plate provided; and a light transmittance of the diffusion plate is changed in a longitudinal direction of the light guide. 6. An optical reading device that irradiates light to a read portion and reads information of the read portion by reflected light thereof, comprising: a light emitting portion that emits light; and a light emitting device that emits light from the light emitting portion. A light guide that guides the light, a rod lens group that receives light emitted from the light emitting unit and reflects the light to be read, and a light receiving element that receives light from the rod lens group; An optical reader, wherein the surface has fine irregularities, and the irregularities are changed in the longitudinal direction of the light guide. 7. An optical reading device that irradiates light to a read portion and reads information of the read portion by reflected light thereof, comprising: a light emitting portion that emits light; and a light from the light emitting portion. The light guide includes a light guide, and a light diffusing member that diffuses the light of the light emitting unit. The light guide includes a reflection unit that reflects light at a position facing the light emitting surface. Optical reader.