JPH05110763A - Line sensor head - Google Patents

Abstract

PURPOSE:To enhance the brightness on a light collection face and to improve the detection capability of the sensor head by forming a reflecting face to a side of a light source side. CONSTITUTION:A light emitted from a rod light source 1 is collected efficiently to a light collection face 3 with a reflection mirror 2, and the reflection light from the light collection face is collected by a photodetector 5 with a lend 4 (e.g. rod lens). The light from the rod light source 1 is emitted in every direction, and the light emitted in a direction as, e.g. a light ray (a) is not collected by the light collection face 3, and since the light from the side face of the lens 4 or from the rod light source 1 is not made incident directly (or indirectly) in the photodetector 5, a reflecting layer 7 is provided to a side face of a light shield plate 6. Thus, the light ray (a) is reflected as, e.g. the light ray a1 by the reflection layer 7 and reflected in the reflection mirror 2 as a light ray a2. Furthermore, the ray a2 is reflected in the reflection mirror 2 and led to the light collection face as a light ray a3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line sensor head used for a line inspection device or the like.

[0002]

2. Description of the Related Art A typical conventional structure of a linear sensor head using a rod-shaped light source (for example, a fluorescent lamp) is shown in the sectional view of FIG. In the sensor head having such a configuration,
It is necessary to efficiently collect light from the rod-shaped light source 1 on the focal plane 3 of the lens 4. Therefore, a reflecting mirror 2 for reflecting the light from the rod-shaped light source 1 and guiding the light to the focal plane 3 is usually used as shown in the figure. Conventionally, in order to improve the light-collecting efficiency, a reflecting mirror having a parabolic or aspherical shape has been used.

[0003]

However, when such a conventional device is used for the purpose of performing inspection by shortening the focal length of the lens, as shown in FIG. Is blocked by the condenser lens and the light does not reach the condenser surface, resulting in the inconvenience that the brightness of the condenser surface is reduced. Also, in order to avoid being blocked by the condenser lens, the light source may be installed away from the condenser lens. In this case, the sensor head outer diameter must be increased by the distance. There is an inconvenience that the distance from the light surface to the light source increases and the loss of light amount in space increases.

The present invention has been made based on the above background, and an object of the present invention is to provide a sensor head capable of increasing the brightness on the light collecting surface and enhancing the detection capability of the sensor head. To provide.

[0005]

The above-mentioned problems can be solved by the present invention. That is, the sensor head of the present invention is a sensor head that receives light from a detection target illuminated by a rod-shaped light source provided with a reflecting mirror by a linear sensor (including an image sensor) in which light-receiving elements are arranged, By providing a reflecting surface on the side surface of the lens for forming an image of the illuminated detection target on the linear sensor, and / or on the side surface of the light shielding plate that prevents light from the rod-shaped light source from entering, It is characterized in that a reflecting surface is formed laterally on the light source side. In a preferred aspect of the present invention, the lens and the light shielding plate side of the reflecting mirror are spherical to reflect the light toward the light source side, and the other side can be used as a parabolic surface to focus the light ray from the light source on the imaging position of the detection target. .

[0006]

The present invention having the above construction exhibits the following operations and actions. Conventionally, the light from the rod-shaped light source is emitted in all directions and is not condensed on the condensing surface. In the present application, since the reflective layer is provided on the side surface of the lens and / or the side surface of the light shielding plate, the light beam is guided to the light condensing surface indirectly or directly by the reflective layer, and the brightness on the light condensing surface is reduced. Can be raised.

In a preferred embodiment of the present invention, the lens side portion of the reflecting mirror is spherical and the other side is parabolic. Thereby, the light emitted from the rod-shaped light source is reflected by the spherical surface of the reflecting mirror, and this light is guided to the light collecting surface 3 by the parabolic reflecting surface. As described above, the light emitted from the rod-shaped light source is efficiently condensed on the light collecting surface by the reflecting mirror,
The light reflected from the light collecting surface is collected by the lens on the light receiving element.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings showing an embodiment.
This will be described more specifically. FIG. 1 is a configuration diagram of a sensor head showing an embodiment of the present invention. The sensor of this embodiment is a sensor head in which light from a detection target illuminated by a rod-shaped light source 1 equipped with a reflecting mirror 2 is received by a line-shaped sensor in which light-receiving elements 5 are aligned, and the sensor of the condenser lens 4 is used. A reflecting surface 7 is provided on the side surface and the side surface of the light shielding plate 6.

The light emitted from the rod-shaped light source 1 is efficiently collected by the reflecting mirror 2 on the light collecting surface 3, and the reflected light from the light collecting surface is collected by the lens 4 (for example, a rod lens) on the light receiving element 5. To be done. The light emitted from the rod-shaped light source 1 is emitted in all directions. For example, the light emitted in the direction of the light ray a is not focused on the light-collecting surface 3, but the light from the side surface of the lens 4 or the light emitted from the rod-shaped light source 1 is directly generated. A reflection layer 7 is provided on the side surface of the light shielding plate 6 so as not to (or indirectly) enter the light receiving element 5.

As a result, the light ray a is reflected by the reflection layer 7 like the light ray a1, and is reflected by the reflecting mirror 2 to become the light ray a2. Further, this light ray is reflected by the reflecting mirror 2 and becomes a light ray a3 and is guided to the light collecting surface 3. In this way, it is possible to guide a part of the light, which was blocked by the conventional lens 4 or the light shielding plate 6 and did not reach the light collecting surface 3, to the light collecting surface by the reflective layer 7, and the brightness on the light collecting surface is reduced. Can be raised. The reflection layer 7 is realized by simply forming a diffuse reflection layer (for example, white paper). Ideally, it is desirable to determine the angle of the reflective layer after performing ray tracing for each point of the reflective layer so that the light from the light source is guided to the converging surface 3 as efficiently as possible.

FIG. 2 is a block diagram of a sensor head showing a second embodiment of the present invention. In this embodiment, the portion 2a of the reflecting mirror 2 on the lens 4 side is spherical and the other portion 2b is parabolic. By forming in this way, the light b emitted from the rod-shaped light source 1 is reflected by the spherical surface 2a of the reflecting mirror 2 in the direction of the light ray b1, and this light is reflected by the parabolic reflection surface 2b to become the light ray b2, which is the light collecting surface. Can lead to 3.

[0012]

As described above, according to the present invention,
It is possible to guide a part of the light blocked by the lens or the light shielding plate to the light collecting surface, and it is possible to increase the brightness of the light collecting surface. As a result, the detection capability of the sensor head can be increased, and the performance of the inspection device as a whole can be improved. Further, since the method of changing the shape of the reflecting mirror or adding the reflecting layer can increase the light amount without changing the conventional outer shape, it is not necessary to upsize the sensor head. Conversely, if the amount of light is the same, it is possible to reduce the outer shape.

[Brief description of drawings]

FIG. 1 is a cross-sectional view for explaining an embodiment of a sensor head of the present invention.

FIG. 2 is a sectional view for explaining another embodiment of the sensor head of the present invention.

FIG. 3 is a cross-sectional view showing a conventional example.

FIG. 4 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

 1 Rod-shaped light source 2 Reflector 3 Condensing surface 4 Condensing lens 5 Light receiving element 6 Light-shielding plate 7 Reflective layer

Claims (2)

[Claims] 1. A sensor head in which light from a detection target illuminated by a rod-shaped light source equipped with a reflecting mirror is received by a linear sensor in which light-receiving elements are aligned, and the illuminated detection target is on the linear sensor. The reflecting surface is formed on the side of the light source by providing the reflecting surface on the side surface of the lens for forming an image on the light source and / or the side surface of the light shielding plate that prevents light from the rod-shaped light source from entering. The sensor head is characterized by 2. A lens of a reflecting mirror and a light-shielding plate side are made spherical to reflect light to the light source side, and the other side is made to be a paraboloid so that a light beam from the light source is condensed at an image pickup position of a detection target. The sensor head according to claim 1, which is characterized in that.