JPH0644264U - Image input device - Google Patents

Abstract

(57) [Abstract] [Purpose] To realize a novel image input device that can easily adjust the optical system and the line sensor, which is indispensable for realizing proper image input. When a subject moving in a predetermined direction passes through a predetermined position while being illuminated by an illuminating means, an image of a surface to be inspected in a direction perpendicular to the moving direction of the subject is formed by an image forming optical system of a light receiving unit of a line sensor. A device for forming an image on the top and sequentially reading it line by line, and converting it into an image signal. By interposing a plane mirror 12 between a guide surface for guiding a moving subject and the image forming optical system, Light from the surface to be inspected is made incident on the imaging optical system 14 via the plane mirror 12, and in the plane in which the light receiving surface of the line sensor is arranged, the direction corresponding to the conveyance direction of the object is the X direction, and the line When the direction in which the longitudinal direction of the light receiving surface of the sensor should be set is the Y direction and the Z axis is taken in the direction orthogonal to the plane at the central portion in the longitudinal direction of the light receiving surface of the line sensor, the image forming position at the predetermined position and the above Receiving X between the surface of the surrounding alignment in the Y direction and the Z-axis is carried out by state position adjustment of the plane mirror 12 to adjust the X and / or Y direction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to an image input device.

[0002]

[Prior art]

 An image input device that reads the state of the subject surface of the subject with an image sensor and converts it into an image signal is widely known as a coin discriminating machine, an inspection device for various works, and the like. As one type of such an image input device, “when an object moving in a predetermined direction passes through a predetermined position while being illuminated by an illuminating means, an image of a portion of a test surface in a direction orthogonal to the direction of movement of the object is formed. An apparatus is known in which an image is formed on a light receiving portion of a line sensor by an image optical system, and is sequentially read line by line and converted into an image signal (Japanese Patent Laid-Open No. 4-52877). Since the present invention relates to an improvement of the image input device disclosed in the above publication, the image input device will be briefly described below.

In FIG. 3A, reference numeral 10 is a glass plate, reference numeral 12 is a plane mirror, reference numeral 14 is an image forming lens as an image forming optical system, and reference numeral 16 is a line sensor (one-dimensional CCD). The glass plate 10, the plane mirror 12, the imaging lens 14, and the line sensor 16 are united by a casing 30 together with an illumination light source device (not shown). The plane mirror 12 and the imaging lens 14 are adjusted so that the surface of the glass plate 10 and a virtual plane indicated by reference numeral 20 in the figure have a conjugate imaging relationship. Therefore, when an object 0 such as a work is placed on the glass plate 10 and the surface on the glass plate 10 side, that is, the surface to be inspected is illuminated by an illumination light source device (not shown), the image of the surface to be inspected is a virtual plane. Image on 20. The surface of the glass plate 10 is a guide surface for the subject 0.

As shown in FIG. 3B, the line sensor 16 has a line-shaped light-receiving surface 160 for receiving image information for one line, and the light-receiving surface 160 is a virtual plane of FIG. 3A. Deployed to match 20. Therefore, an image of one line of the image of the surface to be inspected is formed on the light receiving surface 160 of the line sensor 16.

Here, considering the optical axis of the imaging lens 14 in FIG. 3 (A), the intersection of this optical axis and the virtual plane 20 is taken as a reference position, and as shown in FIG. 3 (B), X, Consider the Y axis, and consider the Z axis so as to match the optical axis. The Z axis passes through the intersection of the X and Y axes in FIG. 3B and is oriented in the direction orthogonal to the drawing. The direction parallel to the X axis (referred to as the X direction) is the direction orthogonal to the drawing in FIG. 3A, but the subject 0 is transported on the guide surface at a substantially constant velocity in the predetermined direction in the X direction. It

If the line sensor 16 is driven in synchronism with the movement of the subject 0 in the X direction, the line sensor 16 is driven at a predetermined position (passes through the intersection of the optical axis of the imaging lens 10 and the guide surface, and the left and right sides of FIG. The image of the surface to be inspected, which is passing through a linear region extending in the direction), is sequentially converted into an image signal by the line sensor 16 for each line.

In order to realize proper image input in such an image input device, as shown in FIG. 3B, the light receiving surface 160 of the line sensor 16 is placed in a correct position with respect to the X and Y axes. I have to keep it. That is, as shown in FIG. 3B, it is necessary that the Z axis, which coincides with the optical axis of the imaging lens, is located at the central portion in the longitudinal direction of the light receiving section 160 and the longitudinal direction of the light receiving section 160 is parallel to the Y axis. .

In other words, in order for the light receiving unit 160 of the line sensor 16 to take an appropriate position, it is necessary to adjust the position of the line sensor 16 in the X and Y directions and adjust the swing around the Z axis. is there.

The X direction corresponds to the moving direction of the subject 0 on the guide surface of the glass plate 10. Therefore, if the line sensor 16 is misaligned in the X direction, the driving timing of the line sensor 16 and the subject 0 may be different. There is a risk that a part of the surface to be inspected cannot be read in the X direction due to a deviation from the movement in the X direction. Further, the Y direction corresponds to the direction orthogonal to the moving direction of the subject 0 on the guide surface, and if the line sensor 16 is displaced in the Y direction, a part of the subject surface in the Y direction is read. There is a fear that it will not.

Further, if the swing adjustment around the Z-axis is insufficient and the longitudinal direction of the light receiving unit 160 is not exactly parallel to the Y direction, the read image on the surface to be inspected is distorted, and the reproduced image is accurate. It hinders image processing.

Conventionally, in order to adjust the position of the line sensor 16 in the X and Y directions and adjust the swing around the Z axis, as shown in FIG. 3B, a support substrate 18 that supports the line sensor 16 is provided. The engaging holes 18A, 18B, 18C, 18D formed at the four corners of the are formed large so as to be loosely fitted to the engaging screw, and adjustment work is performed by utilizing the play between the engaging screw and the engaging hole. The alignment of the line sensor 16 was extremely troublesome, and the efficiency of the assembly of the image input device was poor.

[0012]

[Problems to be solved by the device]

 The present invention has been made in view of the above-mentioned circumstances, and is a novel image input device capable of easily performing the above-described adjustment of the optical system and the line sensor, which is indispensable for realizing proper image input. For the purpose of providing.

[0013]

[Means for Solving the Problems]

 According to the image input device of the present invention, "when an object moving in a predetermined direction passes through a predetermined position while being illuminated by an illuminating means, an image of an area of the surface to be inspected in a direction orthogonal to the moving direction of the object is formed by an imaging optical system. The image is formed on the light-receiving portion of the line sensor and sequentially read one line at a time to be converted into an image signal, which is characterized by the following points.

That is, by interposing a plane mirror between the guide surface for guiding the moving subject and the imaging optical system, the light from the surface to be examined is incident on the imaging optical system via the plane mirror. To

In the plane in which the light receiving surface of the line sensor is arranged, the direction corresponding to the transport direction of the subject is defined as the X direction, and the direction in which the longitudinal direction of the light receiving surface of the line sensor is to be set is the Y direction. When the Z-axis is taken in the direction perpendicular to the plane at the center of the light-receiving surface of the sensor in the longitudinal direction, position adjustment around the Z-axis and the X- and Y-directions between the image-forming position at the predetermined position and the light-receiving surface. Among them, the X direction and / or the Y direction is adjusted by adjusting the position of the plane mirror.

In the position adjustment, the plane mirror is “adjustable to swing about an axis parallel to the X direction”, and the line sensor is “adjustable to swing about the Z axis and adjustable in displacement in the Y direction”. Alternatively, the plane mirror may be “adjustable to swing about an axis parallel to the Y direction” and the line sensor may be “adjustable to swing about the Z axis and X. The displacement can be adjusted in the direction "(claim 3). Alternatively, the plane mirror may be independently swingable about an axis parallel to the X direction and an axis parallel to the Y direction, and the line sensor may be swingable only around the Z axis.

[0017]

[Action]

 As described above, in the present invention, of the position adjustment in the X and Y directions and the swing adjustment about the Z axis, the position adjustment in the X direction and / or the Y direction is performed by adjusting the position of the plane mirror. Thus, the image at the predetermined position on the guide surface is matched with the light receiving surface position of the line sensor.

[0018]

【Example】

 FIG. 1 is a diagram for explaining one embodiment in which the invention is applied to the image input device of FIG. To avoid complications, the same symbols as in Fig. 3 are used for those that are not likely to be confused. In FIG. 1A, the direction orthogonal to the drawing is the X 1 direction. This embodiment is an embodiment of the invention according to claim 2.

The plane mirror 12 is held on a slope portion of a support body 121 having a triangular cross section, and the support body 121 is brought into contact with a support substrate 130 by a projection 122, and a screw 140 penetrating the substrate 130 is attached to the support body 121. It is screwed. An abutment piece 123 is projected from the threaded portion and the support portion on the opposite side via the projection 122, and is restrained from the upper side by a leaf spring 141 whose base is fixed to the supporting substrate 130 by a fixing screw 142. ing. Therefore, when the engaging screw 140 is “forwarded / returned”, the plane mirror 12 has an imaginary axis parallel to the X direction (direction orthogonal to the drawing) with the contact portion between the projection 122 and the support substrate 130 as a fulcrum. Swing around. By utilizing this swing, the image at a predetermined position on the object guide surface is formed at an appropriate position in the Y direction of the light receiving surface of the line sensor (the direction in which the length direction of the light receiving surface is set). To

In the line sensor, as shown in FIG. 1B, a long hole 51 in the X direction is provided in a support plate 50 for fixing the support substrate 18 supporting the line sensor 16, and this long hole is formed. The fixed screw 18 </ b> A that has passed therethrough is screwed onto the support substrate 18. Then, the position of the line sensor 16 is adjusted so that the length direction of the light receiving portion is parallel to the Y direction by the displacement of the support substrate 18 in the X direction and the swinging around the fixing screw 18A. Adjust to occupy the correct position.

FIG. 1C shows a state in which the image of a predetermined position on the inner surface of the subject is adjusted to an appropriate position in the Y direction of the line sensor by adjusting the position of the plane mirror 12 in this embodiment. There is. It is assumed that the light-receiving surface position of the line sensor is displaced by a small distance Δy ′ in the Y direction, and the mirror surface of the plane mirror 12 is rotated by Δθ for adjustment.

As shown in the figure, when the distances: S, S ′, g and the angles: Δu, Δu ′ are taken, the imaging magnification of the imaging lens 14: β (= S ′ / S) is used, and Δy ′ = If β · Δy, Δy = (S−g) · Δu is used, Δy ′ = β · Δy and Δy ′ = β · (S−g) · Δu. On the other hand, since the angle: Δu is 1/2 of the rotation angle of the plane mirror 12: Δθ, Δθ = Δy ′ / {2β · (S−g)}.

For example, if Δy ′ = 0.1 mm, (S−g) = S / 2, β = −0.1, and S ′ (= β · S) = 5 mm, then Δθ = 1.15 degrees, It is easier to adjust the position by rotating the angle of the plane mirror 12 by 1.05 degrees than adjusting the line sensor itself in the Y direction by 0.1 mm.

FIG. 2 shows another embodiment. Here, the same reference numerals as those in FIG. 3 are used for those which are not considered to be confused. This embodiment is an embodiment of the device according to claim 3.

The plane mirror 12 is held on a slope portion of a support body 124 having a substantially triangular cross section, and the support body 124 has a columnar protrusion 125 formed on the bottom surface thereof on the support substrate 133. It is a perfect fit. Engagement holes 133A and 133B are formed in the board 133, and screws 142 and 143 penetrating the engagement holes 133A and 133 are screwed into the support 123. The engagement holes 133A and 133 have “play” with respect to the screws 142 and 143 passing therethrough, and within the range of this play, the support body 124 is swung about the protrusion 125 as an axis to be positioned. Adjustment is performed, and then the screws 142 and 143 are tightened to fix the position of the plane mirror 12 to the adjustment position. The swing axis of this plane mirror is parallel to the Y direction and coincides with the optical axis optical path of the imaging lens (not shown).

As described above, when the position of the plane mirror 12 is adjusted by swinging, the image of the imaging lens at a predetermined position on the guide surface can be displaced and adjusted in the X direction with respect to the light receiving surface of the line sensor. .

Therefore, in this case, in the line sensor, as shown in FIG. 2C, a long hole 53 in the Y direction is provided in the support plate 52 for fixing the support substrate 18 supporting the line sensor 16, and the length of the long hole 53 is increased. The fixed screw 18A having the hole penetrated is screwed into the support substrate 18. Then, the position of the line sensor 16 is set so that the length direction of the light receiving portion becomes parallel to the Y direction by the displacement of the support substrate 18 in the Y direction and the swinging around the fixing screw 18A. Adjust to occupy the proper position in the Y direction.

In each of the embodiments described above, the position adjustment of the plane mirror 12 is performed only in one of the X and Y directions. However, by combining the adjustment mechanism described above, the plane mirror can be adjusted in both the X and Y directions. The position of the line sensor can be adjusted by adjusting the position of the line sensor.

[0029]

[Effect of device]

 As described above, according to this invention, a new image input device can be provided. This device is configured as described above, and the alignment between the predetermined position of the guide surface and the line sensor is performed by adjusting the plane mirror on the optical path and the line sensor, so that the adjustment work is easy and the assembly is easy.

[Brief description of drawings]

FIG. 1 is a diagram for explaining one embodiment of the present invention.

FIG. 2 is a diagram for explaining another embodiment.

FIG. 3 is a diagram for explaining a conventional technique and its problems.

[Explanation of symbols]

 12 plane mirror 14 imaging optical system 121 support 130 support substrate 141 leaf spring 140 screw

Claims (3)

[Scope of utility model registration request] 1. When an object moving in a predetermined direction passes through a predetermined position while being illuminated by an illuminating means, an image of a surface to be inspected in a direction orthogonal to the moving direction of the object is formed by an imaging optical system of a line sensor. A device for forming an image on a light receiving unit and sequentially reading one line at a time and converting the image signal into an image signal. , The light from the surface to be inspected is made incident on the imaging optical system through the plane mirror, and in the plane in which the light receiving surface of the line sensor is arranged, the direction corresponding to the transportation direction of the object is set to the X direction. When the longitudinal direction of the light receiving surface of the line sensor is to be set to the Y direction and the Z axis is taken in the direction orthogonal to the plane at the central portion in the longitudinal direction of the light receiving surface of the line sensor, the predetermined position X between the imaging position and the light-receiving surface,
An image input device characterized in that, among the position adjustments around the Y direction and the Z axis, the X direction and / or the Y direction is adjusted by adjusting the position of the plane mirror. 2. The image input device according to claim 1, wherein the plane mirror is swingable about an axis parallel to the X direction, and the line sensor is swingable about the Z axis and in the Y direction. An image input device characterized in that its displacement can be adjusted. 3. The image input device according to claim 1, wherein the plane mirror is swingable about an axis parallel to the Y direction, and the line sensor is swingable about the Z axis and in the X direction. An image input device characterized in that its displacement can be adjusted.