JPH05103157A - Lighting device for image reader - Google Patents

Abstract

PURPOSE:To reduce the amount of parts and to obtain clear original image even when the assembling tolerance of parts exists. CONSTITUTION:With regard to an original reader's lighting device in which the surface of an image medium to be read is lighted and then the read image information is converted into electric signals, a light source array 2 in which plural light sources are arranged in a straight line for lighting an image media and a cylindrical lens 5 having a convex lens 6 for condensing light beam from the light source array 2 are provided. The cylindrical lens 5 is positioned between the image medium and the light source array 2 and the light source array 2 is used as a component for constituting hausings 1, 3 and 5 in which the light source array 2 is housed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination device for illuminating a document surface of an image reading device.

2. Description of the Related Art Conventionally, a facsimile, a copying machine, an OCR
(Optical Character Reader), ATM (Automatic Tel
In an image reading device such as a ler machine), an LED array in which a large number of LED chips are arranged is known as a small illumination device for a document surface.

FIG. 5 and FIG. 6 are schematic sectional views of an illumination device of an image reading device which has been conventionally used. The illumination device of FIG. 5 is a transmissive type, and a condenser lens 33 is arranged on the light emitting surface side of the LED array 32 on the substrate 31 with an interval, and the LED array 32 is provided on both side surfaces of the LED array 32.
A reflecting plate 35 that also serves to reflect the illumination light and to support the condenser lens 33 is arranged. Then, a support 36 is provided on the substrate 31 so as to surround these members. This support 3
In order to transmit the light flux from the LED array 32, the ceiling portion of 6 has a transparent plate 37 made of glass or a plastic plate.
It is composed of.

Although not shown, an image sensor array is arranged above the illuminating device at a distance from the illuminating device, and a document such as a bill is conveyed at high speed between the illuminating device and the image sensor array. It Since the light flux from the illumination device transmits the document, the image sensor array can receive the document image.

The illumination device of FIG. 6 is a reflection type illumination device, and like the LED array 32 of FIG. 5, the LED array 42, the reflector 43 and the condenser lens 45 are provided on the substrate 41 on one side. 46 is arranged in an inclined shape. A rod-shaped rod lens 49 is arranged on the support 47 on the other side of the substrate 41. An image sensor array 50 is arranged on the image sensor array back plate 51 below the rod lens 49. A transparent plate 52 is provided on the ceiling of the supports 46 and 47.
Since the upper surface of the transparent plate 52 is flat, when a document is placed on the transparent plate 52, the light flux from the LED array 42 transfers the image on the document surface to the image sensor array 50 via the rod lens 49. Can be sent. The image sensor array 50 outputs the document reading information as an electric signal to a control circuit (not shown).

[0005]

The illumination device of the image reading device shown in FIGS. 5 and 6 has the following problems.

That is, the above-mentioned conventional lighting device is LE
In addition to the D arrays 32 and 42, the condenser lenses 33 and 45, the reflection plates 35 and 43, and the transparent plates 37 and 52 are indispensable constituent members, so that there is a problem that the number of parts increases and the manufacturing cost increases. Further, as shown in FIG. 7, the light from the LED array is condensed by the condenser lenses 33 and 45, and the original 57
(In the case of FIG. 6, in the case of FIG. 5, the original 57 is located at a position spaced from the transparent plate 37 in the case of FIG. 5.) When the light reaches the original, the light amount distribution density on the original surface becomes high and the parts are narrowed. If there is an assembly tolerance, it will be strongly reflected, and the original image may not be obtained clearly.

Therefore, an object of the present invention is to provide an illuminating device for an image reading device in which the number of parts is reduced. Another object of the present invention is to provide an illuminating device of an image reading device which can obtain a clear original image even if there are assembly tolerances of parts.

[0008]

The above object of the present invention can be achieved by the following constitutions. That is, in a lighting device of an image reading device that illuminates a reading surface of an image medium and converts the read image information into an electric signal, a light source array for illuminating the image medium, in which a plurality of light sources are linearly arranged, and the light source. It has a condensing structure for condensing the light flux from the array, and comprises a cylindrical lens for illuminating the reading surface of the image medium, and the cylindrical lens is arranged between the image medium and the light source array, and the light source array is housed inside thereof. The illumination device (first invention) of the image reading device configured as a part of the housing.

Here, the condensing structure of the cylindrical lens is composed of a lens portion having a convex lens-shaped cross section.
This condensing structure preferably has a convex lens shape, is provided on the side surface on the light source side, and the light source array is arranged at a position corresponding to the focal length of the convex lens portion. In this case, the luminous flux from the light source is emitted as a parallel luminous flux toward the image medium by the cylindrical lens.

The object of the present invention can also be achieved by the following configuration. That is, in a lighting device of an image reading device that illuminates a reading surface of an image medium and converts the read image information into an electric signal, a light source array for illuminating the image medium, in which a plurality of light sources are linearly arranged, and the light source. A cylindrical lens that collects the light flux from the array and illuminates the reading surface of the image medium, a condenser lens that collects the reflected light from the image medium on the cylindrical lens, and a condenser lens that collects the light. An image sensor array for converting image information of an image medium into an electric signal by a light flux. The cylindrical lens has a light condensing structure on its side surface on the light source array side, and has its side surface on the image medium mounting side. Image reading having a planar structure for use as a part of a housing that houses the light source array, the condenser lens, and the image sensor array therein. An illumination device of the apparatus (the second invention).

In this case, the condensing structure of the cylindrical lens may be the same as that of the first invention. However, one side surface of the cylindrical lens needs to have a planar shape for mounting the image medium,
The light collecting structure is provided on the side surface on the light source array side. The light condensing structure is preferably a convex lens shape, and the light source array is arranged at a position corresponding to the focal length of the convex lens portion, and the light flux from the light source is emitted toward the image medium as a parallel light flux by the cylindrical lens.

[0012]

When the condensing structure of the cylindrical lens according to the first aspect of the present invention has a convex lens shape and is provided on the side surface on the light source array side and the light source array is arranged at a position corresponding to the focal length of the convex lens portion, The light flux from the light source array becomes a parallel light flux due to the condensing structure of the cylindrical lens, and is emitted from the side surface of the image medium on the original surface side. Then, the parallel light flux passes through the document surface of the image medium and is input to the image reading device.

Also in the second invention of the present invention, when the condensing structure of the cylindrical lens is formed into a convex lens shape and the light source array is arranged at a position corresponding to the focal length of the convex lens portion, the light flux from the light source array is emitted. Is a parallel light flux due to the condensing structure of the cylindrical lens, irradiates the original surface of the cylindrical lens on the original mounting surface side of the cylindrical lens, and the reflected light is focused by the condensing lens and input to the image sensor array.

With the above structure, since the light flux from the light source array is emitted as a parallel light flux by the cylindrical lens of the present invention, the light amount is uniformly distributed on the original surface of the image medium, and the illumination device is slightly different. By absorbing the assembly tolerance of, the original surface can be read clearly.

Further, in the illuminating device of the present invention, the lens for condensing the light flux from the light source is used as a lens protection plate (first invention, second invention) or is also used as an original document placing table (second invention). ), The number of parts is small.

[0016]

Embodiments of the present invention will be described with reference to the drawings. Example 1 FIG. 1 shows a perspective view of an example of a transmissive illumination device, and FIG.
The cross section is shown in FIG. As shown in FIGS. 1 and 2, this lighting device has an LED array 2 arranged on a substrate 1,
Cylindrical lenses 5 supported by a support 3 on the substrate 1 are arranged at intervals on the light emitting surface side of the D array 2. The LED array 2 is a linear array of a large number of LED chips (not shown). The support 2 on the substrate 1 and the cylindrical lens 5 may be bonded to each other with an adhesive or the like, or may be integrally molded and bonded to the substrate 1 with an adhesive or the like.

The cylindrical lens 5 has a sectional shape as shown in FIG. 3, the LED array 2 side is a convex lens portion 6 having a semicircular sectional shape, and the original side is a planar shape.
The distance between the LED array 2 and the convex lens portion 6 of the cylindrical lens 5 is kept at a distance corresponding to the focal length of the convex lens portion 6. Therefore, the light beam from the LED array 2 is emitted as a parallel light beam to a document (not shown). In this way, a parallel light beam is incident on the document above the illuminating device (not shown) in FIG. 1, and the light beam transmitted through the document causes an image signal of the document surface to be converted into an electrical signal through a detection device such as an image sensor array (not shown). Is converted to.

In this embodiment, since the light beams incident on the document surface are parallel, the light amount distribution on the document surface is uniform and the allowable range of component assembly tolerance is wide. Of course, the light flux incident on the document surface may be narrowed by the cylindrical lens 5, but in that case, the light amount distribution on the document surface becomes non-uniform, and the allowable range of the tolerance becomes small.

The lighting device of this embodiment is used for a bill counter (ATM) or the like. In this case, the bill is transported at high speed in the space between the cylindrical lens 5 and the image sensor array (not shown). Therefore, the cylindrical lens 5 also has a function as a protective plate of the LED array 2 so that the bill does not come into contact with the LED array 2.

Embodiment 2 FIG. 4 shows an embodiment of a reflection type illumination device. Similar to the LED array 2 shown in FIGS. 1 and 2, the LED array 12 is arranged on the substrate 11 on one side in an inclined manner. LE
The D array 12 is a linear array of many LED chips (not shown). Then, the support 1 for supporting the rod lens 15 adjacent to the LED array 12
6 is provided on the other side of the substrate 11. An image sensor array 17 is arranged below the rod lens 15 on an image sensor array back plate 19. On the image sensor array back plate 19, a read IC 20 wire-bonded to the image sensor array 17 is also arranged. The support 13 for supporting the LED array 12, the support 16 for supporting the rod lens 15 and the back plate 19 of the image sensor array are bonded onto the substrate 11.

A cylindrical lens 21 is bonded to the tops of the supports 13 and 16, and the cylindrical lens 21 constitutes a housing together with the substrate 11, the supports 13 and 16, and the LED array 12, The rod lens 15, the image sensor array 17, etc. are housed. This cylindrical lens 21 and support 13,
Although 16 may be manufactured as a separate body and bonded with an adhesive or the like, they may be integrally molded.

There is a convex lens portion 22 on the side surface of the cylindrical lens 21 on the LED array 12 side, and the side surface on the opposite side is flat so that a document can be placed. The convex lens portion 22 of the cylindrical lens 21 sets its focal length so that the light beam from the LED array 12 can be irradiated as a parallel light beam on the document surface placed on the flat surface side of the cylindrical lens 21. Then, the reflected light from the document surface passes through the cylindrical lens 21, is narrowed down by the rod lens 15, and forms an image on the image sensor array 17.

The image signal of the original obtained by the image sensor array 17 is transmitted to a computer (not shown) via the image reading IC 20.

In this embodiment as well, as in the first embodiment, since the light beams incident on the document surface are parallel, the light amount distribution on the document surface is uniform, and the allowable range of component assembly tolerance can be widened. Of course, the light flux incident on the document surface may be narrowed by the cylindrical lens 21, but in that case, the light amount distribution on the document surface becomes non-uniform, and the allowable range of the tolerance becomes small.

The lighting device of this embodiment is used for a facsimile, a small copying machine, an OCR, and the like. In this case, the original can be placed on the flat side surface of the cylindrical lens 21, and the cylindrical lens 21 has a function as a condenser lens and a function as an original placing table.

The cylindrical lenses 5 and 21 of Examples 1 and 2 can be easily molded from glass or plastic. In addition, the LED array 2,
Instead of 12, other heating wires, other light sources such as a halogen lamp may be used.

[0027]

According to the present invention, the lens for condensing the light beam from the light source is used as the lens protection plate (first invention, second invention) or is also used as the original placing table, as compared with the conventional product. (Second invention) The number of parts is small.

Further, when the luminous flux from the light source array is emitted as a parallel luminous flux by the cylindrical lens of the present invention, the light quantity is uniformly distributed on the original surface of the image medium,
The original surface can be read clearly by absorbing some assembly tolerances of the lighting device.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is a cross-sectional view of FIG.

FIG. 3 is a diagram showing a luminous flux from an LED chip when the cylindrical lens of FIG. 1 is used.

FIG. 4 is a sectional view of an embodiment of the present invention.

FIG. 5 is a cross-sectional view of a lighting device using a conventional LED array.

FIG. 6 is a cross-sectional view of a lighting device using a conventional LED array.

FIG. 7 is an explanatory diagram in the case of illuminating an image medium by focusing a light beam by a lens.

[Explanation of symbols]

1, 11, 31, 41 ... Substrate, 2, 12, 32, 42 ...
LED array, 3, 13, 16, 36, 46, 47 ... Support, 5, 21 ... Cylindrical lens, 6, 22 ...
Convex lens part, 15, 49 ... Rod lens, 17, 50
Image sensor array, 19, 51 ... Image sensor array back plate, 20 ... Read IC

Claims (2)

[Claims] 1. A light source array for illuminating an image medium, comprising: a light source array for illuminating a reading surface of an image medium to convert the read image information into an electric signal; , Having a condensing structure for condensing the light flux from the light source array,
And a cylindrical lens for illuminating a reading surface of the image medium, wherein the cylindrical lens is arranged between the image medium and the light source array, and the light source array is configured as a part of a housing housed therein. Lighting device for image reading device. 2. A light source array for illuminating an image medium, comprising: a plurality of light sources linearly arranged in an illuminating device of an image reading apparatus that illuminates a reading surface of the image medium and converts the read image information into an electric signal. A cylindrical lens that collects the light flux from the light source array and illuminates the reading surface of the image medium, a collective lens that collects the reflected light from the image medium on the cylindrical lens, and a collective lens that collects the light. An image sensor array for converting image information of an image medium into an electric signal by a light beam emitted, the cylindrical lens has a light condensing structure on its side surface on the light source array side, and an image on the side surface on the image medium side. It has a plane structure for mounting a medium, and is configured as a part of a housing for accommodating the light source array, the condenser lens and the image sensor array inside. Lighting device of the image reading apparatus according to claim.