JP2000312305A - Linear camera apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an excellent photographing result by increasing a lighting luminous quantity emitted on a subject up so as to increase a quantity of a reflected light from the body to be picked up thereby ensuring the sufficient luminous quantity for image forming even when a carrying speed of the subject. SOLUTION: A slit aperture 21 is formed to a case at a side of a carrying path of parts to be inspected, mirror surfaces 32, 32 are placed in parallel with the aperture 21 in a way that they are being curved to form a cross-section with an elliptic-arc and one focus P2 of the ellipse is in matching with the parts to be inspected on the aperture 21, and straight line type fluorescent lights 33, 33 are placed on the other foci P1, P3. Thus, lighting lights are collected and emitted onto the parts to be inspected and an image of the parts to be inspected is formed by a micro lens 40 in the inside of the case via the aperture 21 and a linear image sensor 50 placed at an image forming position is electronically scanned, then even when the carrying speed of the parts to be inspected is increased, a sufficient luminous quantity for image forming can be obtained and an excellent photographing result can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a linear camera device using a so-called linear image sensor.

[0002]

2. Description of the Related Art Many reading apparatuses such as facsimile machines and scanners use a so-called close contact type linear image sensor. In this type of reading device, an original reading surface is irradiated with illumination light using an LED or the like,
The linear image sensor is almost continuously electronically scanned while the original is conveyed in the sub-scanning direction so as to be in close contact with the light receiving portion of the linear image sensor arranged in the main scanning direction, and predetermined image data is generated. .

[0003]

The above-mentioned prior art has the following problems. A contact-type linear image sensor is used, and the illumination brightness provided in the sensor is low. Therefore, when the transport speed is increased, the amount of light required for image formation is not sufficient, and a good imaging result cannot be obtained. The transport speed does not matter much if it is used for normal facsimile or scanner,
In the case of using as a camera in an FA (Factory Automation) line, if the transport speed cannot be increased, the efficiency is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and provides an image pickup device that conveys an object to be imaged by substantially continuously electronically scanning a linear image sensor arranged in the main scanning direction. It is an object of the present invention to provide a linear camera device capable of improving the transport speed of an object while ensuring the result.

[0005]

In order to achieve the above object, the invention according to claim 1 comprises a housing having a slit-shaped opening formed on the side of a conveyance path of an object to be imaged, and a housing having a slit-shaped opening formed thereon. The reflector is arranged side by side in the opening, and has a reflecting mirror whose one focal point of the ellipse substantially matches the position of the imaging object on the opening while being curved so as to form an arc of a cross section ellipse. An illumination block having a substantially linear light source at a focal point; an optical lens that forms an image of the object to be imaged inside the housing through the opening; and a linear image disposed at an image forming position of the optical lens. And a sensor.

[0006] In the first aspect of the present invention, a slit-shaped opening is formed in the housing of the linear camera device, and the side on which the opening is formed is used as a transport path for the object to be imaged. Is transported. On the upper surface of the housing, the one focal point of the ellipse substantially coincides with the position of the imaging object on the opening while being arranged side by side with the opening and curved so as to form an arc having a cross-sectional ellipse. An illumination block having a reflector and a substantially linear light source at the other focal point is provided.
Here, the light from the substantially linear light source at one focal point of the ellipse tends to be appropriately reflected by the reflecting mirror and collected at the other focal point, and is reflected by the object to be conveyed over the opening. Then, the reflected light is introduced into the inside of the housing through the opening, an image of the object to be imaged is formed by the optical lens, and electronic scanning is performed by the linear image sensor arranged at the image forming position.

[0007] The linear image sensor here is
A device that generates predetermined image data by reading reflected light from an imaging object with a light receiving element extending in a width direction (main scanning direction) while conveying the imaging object in a length direction (sub-scanning direction). It is. Therefore, as described above, when the illumination light from the substantially linear light source is collected by the reflecting mirror and irradiated on the object, the amount of reflected light also increases. For this reason, even if the conveyance speed of the object to be imaged is increased, a sufficient amount of light for image formation can be obtained, and a good image pickup result by the linear image sensor can be obtained.

[0008] An object of the present invention is to increase the amount of illumination applied to the object to be illuminated and to increase the amount of light reflected from the object to be illuminated. An object of the present invention is to secure a sufficient amount of light and obtain a good imaging result. Therefore, it is preferable that the substantially linear light source provided in the illumination block has a large light emission amount. As an example, the invention according to claim 2 is the linear camera device according to claim 1, wherein the substantially linear light source in the illumination block is a straight tube fluorescent lamp. In the invention according to claim 2 configured as described above, in the reflecting mirror curved so as to form an arc having an elliptical cross section, light from a straight tube fluorescent lamp provided at one focal point is reflected by the reflecting mirror. The light is appropriately reflected and gathers at the position of the imaging object on the opening, which is the other focal point.

If the depth of the reflecting mirror that forms the arc having the elliptical cross section is small, most of the illuminating light on the upper surface side of the substantially linear light source is diffused. Seems to be able to irradiate the illumination light. However, when an experiment was conducted, it was found that when the reflecting mirror was deepened, a part of the reflected light bounced back to the substantially linear light source, and the efficiency became worse. Therefore, according to a third aspect of the present invention, in the linear camera device according to any one of the first and second aspects, the substantially linear light source in the illumination block is caused to approach the position of the imaging object on the opening. It is configured to be arranged. That is, when the substantially linear light source in the illumination block is arranged closer to the position of the object to be imaged on the opening, the amount of reflected light introduced into the inside of the housing is larger, and a good imaging result is obtained.

Further, as an example of a configuration for increasing the amount of illumination applied to an object to be imaged, the invention according to claim 4 is as follows.
The linear camera device according to any one of claims 1 to 3, wherein the illumination blocks are arranged symmetrically with respect to the opening. That is, since the reflective illumination blocks are symmetrically arranged with the slit-shaped opening formed in the housing interposed therebetween, the amount of illumination applied to the object to be imaged is also large.

[0011]

As described above, according to the present invention, when a linear image sensor arranged in the main scanning direction is electronically scanned substantially continuously while an object to be imaged is conveyed and an image is taken, an arc having a cross section ellipse is formed. The focal point of one of the reflecting mirrors is made substantially coincident with the position of the object to be imaged on the opening formed in the housing, and the substantially linear light source is arranged at the other focal point to increase the amount of illumination light to the object to be imaged. As a result, it is possible to provide a linear camera device capable of improving the transport speed of the object while maintaining good imaging results. Further, according to the second aspect of the invention, it is possible to provide a preferred example of the substantially linear light source in the lighting block.

Further, according to the third aspect of the present invention,
Since the substantially linear light source in the illumination block is arranged close to the position of the object to be imaged, the amount of reflected light introduced into the inside of the housing is large, and a good image pickup result can be obtained. further,
According to the fourth aspect of the present invention, since the illumination blocks are symmetrically arranged with the opening formed in the housing interposed therebetween, it is possible to further increase the amount of illumination light with respect to the object to be imaged.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a linear camera according to an embodiment of the present invention, and FIG.
This is shown in a perspective side view. In the figure, the linear camera 10 includes a rectangular cylindrical housing 20 having one open end covered, and two substantially box-shaped illumination blocks 30, 30 are provided at the other open end by a predetermined shape. They are housed in the housing 20 so as to be arranged side by side with a gap therebetween. Therefore, the slits 21 are formed by the illumination blocks 30, 30, and the glass plate 22 is placed so as to cover the illumination blocks 30, 30 on the opening 21 side.

In the illumination block 30, as it goes outward from the widthwise end for forming the opening 21,
The concave portion 31 is formed by curving so as to form an arc having a cross-sectional ellipse. Here, referring to the enlarged perspective view of FIG. 3, one concave portion 31 may be curved in accordance with an elliptic arc whose focal point is a point P1 outside the opening 21 and a point P2 on the opening 21. I understand. On the other hand, it can be seen that the other concave portion 31 is similarly curved according to an elliptical arc whose focal points are points P3 and P2 outside the opening 21.

Mirror surfaces 32, 32 are formed on the surfaces of the concave portions 31, 31 by sticking a glossy flexible metal plate or the like, and the focal points P1, P3 have straight surfaces extending in the width direction. Tube-shaped fluorescent lamps 33, 33 are arranged. Therefore, the illumination light from the straight tube fluorescent lamps 33, 33 is appropriately reflected by the mirror surfaces 32, 32. Here, a straight tube fluorescent lamp 33,
Since the reference numeral 33 is disposed at the focal points P1 and P3 of the ellipse, the illumination light reflected by the mirror surfaces 32 and 32 has a characteristic of being collected at the other focal point P2 due to the optical characteristics of the elliptical mirror surface.

The linear camera 10 according to the present embodiment comprises
It is installed in the FA machine and is arranged on the transport path of the inspection component in the factory, and is used for imaging while transporting the inspection component. More specifically, since the focal point P2 is arranged so as to be located on the transport path of the inspection component, the mirror surface 3
The illumination light collected by the light beams 2 and 32 impinges on the inspection component passing through the opening 21 and is reflected, and a part of the light is introduced into the housing 20 through the opening 21. Then, as will be described later, the reflected light introduced into the housing 20 is imaged by an optical lens, and is electronically scanned by a linear image sensor arranged at the image forming position.

Here, the specific shapes of the recesses 31, 31 are as follows:
That is, as the shape of the mirror surfaces 32, 32, if the cross-section ellipse has a shallow depth, most of the illumination light on the upper surface side of the straight tube fluorescent lamps 33, 33 is diffused. Seems to be able to be irradiated.
However, when an experiment was conducted, it was found that a part of the reflected light was reduced by increasing the mirror surfaces 32, 32 so that the straight fluorescent lamp 3 could not be used.
It turned out that it bounced back to 3,33, and on the contrary, it became clear that efficiency became bad. Then, when the mirror surfaces 32, 32 were made shallow and the straight tube fluorescent lamps 33, 33 were brought as close as possible to the inspection parts, it was found that good imaging results could be obtained.

On the other hand, the reflected light introduced into the housing 20 through the opening 21 passes through the gap between the illumination blocks 30 and 30 inside the housing 20 and is transmitted to the microlens 40 installed at the tip of the illumination block 30. Incident. The micro lens 40 is for forming an image of the inspection component through the opening 21, extends in the width direction so as to correspond to the opening 21, and is incident from one end in the height direction. The reflected light is polarized to the other end and projected onto the linear image sensor 50.
It goes without saying that the focus position on the incident side of the microlens 40 is set to the focal point P2, and the focus position on the other end is set to the light receiving element of the linear image sensor 50.

The linear image sensor 50 similarly includes light receiving elements connected in the width direction, and generates image data based on the intensity of light detected by each light receiving element. Needless to say, the resolution of the image differs depending on the installation density of the light receiving elements, and the linear image sensor actually used is appropriately selected according to the application and the like. The linear image sensor 50 is classified as a close contact type from a structural viewpoint, and is distinguished from a lens reduction type. A contact-type linear image sensor, as seen in many facsimile machines and scanners, conveys a document reading surface substantially in close contact with a light-receiving element and substantially continuously electronically scans the document over substantially the entire surface thereof. To read the image.

FIG. 4 is a block diagram showing the electrical connection of the present linear camera 10. In the figure,
An inspection component is transported along a transport path by a transport robot or the like (not shown), and image data is generated by repeating the electronic scanning by the linear image sensor 50 as described above. The image data generated here can be stored in the image memory 61 and can be read when necessary. In addition, the generated image data is
The image is converted into an analog image signal via a C (D / A converter) 62, a video signal is generated by superimposing a synchronizing signal on the image signal by a modulator 63, and supplied to a display 64. Display is possible. The operation control of the entire linear camera 10 including the operation control of various hardware such as the linear image sensor 50 is performed by the microcomputer 65.

By the way, the contact-type linear image sensor originally performs electronic scanning by closely contacting the original reading surface and the light-receiving element. Therefore, a small light source such as an LED is generally used due to the installation space problem. Can be For this reason, since the illumination luminance is low and a sufficient amount of light for imaging cannot be obtained, the transport speed in the sub-scanning direction is set to 200 [mm / sec] at the maximum.
I can't raise it any more. On the other hand, this linear camera 1
At 0, a straight tube-type fluorescent lamp 33 having a large light emission amount is used as a light source, and light is collected by a mirror surface 32 curved so as to form an arc having an elliptical cross section, and is irradiated on an inspection component. For this reason, since the illumination luminance is high and a sufficient amount of light can be obtained, the transport speed of the inspection component is set to 700
It was found that it could be increased to [mm / sec]. In addition, since the contact type linear image sensor has a wide field of view and may pass anywhere within the field of view, it can be said that the degree of freedom in the device configuration is large. Furthermore, since it is a linear image sensor, its length in the length direction is shorter than that of an ordinary camera, so that it can be installed in a narrow space.

Next, the operation of this embodiment configured as described above will be described. When the inspection component is transported according to a predetermined transport path and passes over the opening 21 of the linear camera 10, the illumination light impinges on the inspection component and is reflected, and the reflected light is introduced into the housing 20 through the opening 21. . Specifically, the illumination light from the straight tube-type fluorescent lamps 33, 33 disposed at the respective focal points P1, P3 is appropriately reflected on the mirror surfaces 32, 32 curved so as to form an arc of a cross section ellipse, The light is collected at the other focal point P2 and hits the inspection component and is reflected.

The reflected light introduced into the housing 20 through the opening 21 is reflected by the illumination block 3 inside the housing 20.
The light passes through the gap between 0 and 30 and is incident on the microlens 40 ahead. The reflected light incident on one end of the microlens 40 is polarized to the other end and projected on the linear image sensor 50. The linear image sensor 50 generates image data by repeating electronic scanning under the control of the microcomputer 65. The image data generated here can be stored in the image memory 61 and can be read when necessary. In addition, the generated image data is converted into an analog image signal via the DAC 62, and a video signal is generated by superimposing a synchronization signal on the image signal by the modulator 63, and supplied to the display 64. Screen display is possible.

In the present embodiment, the two illumination blocks 30, 30 are arranged symmetrically with the opening 21 interposed therebetween, but the invention is not necessarily limited to this configuration. For example, as shown in FIG.
The same effect can be obtained even in the case where only 0 is used. Of course, compared to the present embodiment, the illumination luminance is lower, and the upper limit of the transport speed naturally drops.

As described above, the slit-shaped opening 21 is formed in the housing 20 on the transport path side of the inspection component, and the elliptical shape is arranged in parallel with the opening 21 so as to be curved so as to form an arc having a cross-sectional ellipse. One of the focal points P2 has mirror surfaces 32, 32 corresponding to the inspection component on the opening 21 and the other focal point P2
By disposing the straight tube-type fluorescent lamps 33, 33 at 1, P3, the illumination light is collected and irradiated to the inspection component, and the image of the inspection component is transmitted through the opening 21 to the micro lens 4 inside the housing 20.
Since the image is formed at 0 and the linear image sensor 50 arranged at the image forming position is electronically scanned,
It is possible to provide a linear camera device capable of obtaining a sufficient amount of light for image formation and obtaining a good imaging result even when the transport speed of the inspection component is increased.

[Brief description of the drawings]

FIG. 1 is a perspective view of a linear camera according to an embodiment of the present invention.

FIG. 2 is a perspective side view of the linear camera.

FIG. 3 is an enlarged perspective view of the linear camera.

FIG. 4 is a block diagram showing an electrical connection form of the linear camera.

FIG. 5 is a perspective view of a linear camera according to a modification.

[Description of Signs] 10 ... Linear camera 20 ... Case 21 ... Opening 22 ... Glass plate 30 ... Illumination block 31 ... Recess 32 ... Mirror surface 33 ... Straight tube fluorescent lamp 40 ... Micro lens 50 ... Linear image sensor 61 ... Image memory 62: DAC (D / A converter) 63: Modulator 64: Display 65: Microcomputer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F065 BB15 DD00 DD05 FF42 GG16 HH12 HH14 JJ02 JJ09 JJ25 LL10 LL19 LL28 MM03 MM22 QQ24 5C022 AA00 AB15 AC42 AC51 AC54 5C072 BA03 CA04 DA02 DA18 DA10 DA23 EA07 RA10

Claims (4)

[Claims] 1. A housing having a slit-shaped opening formed on the side of a conveyance path of an object to be imaged, and arranged on the upper surface of the housing so as to be arranged in parallel with the opening to form an arc having an elliptical cross section. An illumination block having a reflecting mirror in which one focal point of the ellipse is substantially coincident with the position of the object to be imaged on the opening while being curved, and an illumination block having a substantially linear light source at the other focal point. A linear camera device comprising: an optical lens for forming an image of an object to be imaged inside the housing; and a linear image sensor disposed at an image forming position of the optical lens. 2. The linear camera device according to claim 1, wherein the substantially linear light source in the lighting block is a straight tube fluorescent lamp. 3. The linear camera device according to claim 1, wherein the substantially linear light source in the illumination block is arranged close to a position of an object on the opening. A linear camera device characterized by the above-mentioned. 4. The linear camera device according to claim 1, wherein the illumination block comprises:
A linear camera device, wherein the linear camera device is arranged symmetrically with respect to the opening.