JPH1039219A - Illuminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image in which only groove can be seen floating up in a good contrast state and to make even a small groove formed on the surface on the image confirmable by irradiating a body to be inspected with light in a direction vertical to the extending direction of the groove on the surface of the body to be inspected. SOLUTION: The irradiating direction with an illuminator 15 is controlled by an illuminating direction controller 14 based on a signal showing the direction of diffracted light outputted from an optical sensor 13 so that a hard disk 12 may be illuminated in a direction vertical to the extending direction of the groove 12a on the surface of the hard disk 12. The hard disk 12 is illuminated in a direction vertical to the extending direction of the groove 12 on the surface of the hard disk 12, then, the light scattering from the groove 12a on the surface is intensely made incident into a lens barrel 16, besides, light reflected by parts other than the groove 12a has a strong regular reflection component, so that the only weak light is made incident into the lens barrel 16. Thus, the image with high contrast between the groove 12a and the parts other than the groove 12a is taken in by a CCD line sensor 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device suitable for observing a groove of a subject having a groove on a surface, for example, attached to a microscope or the like.

[0002]

2. Description of the Related Art In order to avoid strong interference with a head for accessing a hard disk, a large number of scratches long in the rotation direction of the hard disk are actively provided on the surface of a hard disk used as a storage device of a computer. A groove is formed. This groove is formed for such a purpose, and the width of the groove and the interval between the grooves are controlled. If the groove is out of the control limit, it becomes a defective product. Conventionally, such surface groove inspection has been carried out by visually inspecting the state of the hard disk surface by placing a light source so as to reflect light well on the hard disk surface and observing the reflected light.

[0003]

As an alternative to the visual inspection, an inspection method is to illuminate the hard disk, take in an image transmitted by the illumination, and observe or calculate a groove shown on the image. It is considered. At this time, how to illuminate the hard disk surface becomes a problem.

FIG. 4 is a schematic view of a microscope to which an illumination device is attached. A ring-shaped illuminating device 42 for irradiating light in a circular shape is arranged around the objective lens 41, and the illuminating device 42 allows the hard disk 43 to have a visual field region D of the objective lens 41 or a periphery thereof. Area is illuminated with a uniform amount of light. The light reflected by the hard disk 43 is incident on the objective lens 41, and the light incident on the objective lens is detected by, for example, a CCD sensor (not shown), and an image of the surface of the hard disk is obtained.

However, in the above-described lighting device 42, since the surface of the hard disk 43 is illuminated by irradiating light in a circular shape, it is difficult to obtain a contrast between the groove portion and the non-groove portion. Irregularities due to surface roughness also appear on the image, and there is a problem that it is difficult to distinguish grooves from irregularities due to surface roughness. In view of the above circumstances, the present invention provides an illuminating device that, when an image of a surface of a subject such as a hard disk is taken, obtains an image in which only grooves are raised with good contrast, and small grooves on the surface can be confirmed on the image. The purpose is to provide.

[0006]

According to the present invention, there is provided an illumination apparatus comprising: (1) an object having a groove extending in a predetermined direction on a surface thereof;
(2) a laser light source for irradiating the object surface with laser light; and (3) a laser arranged on a diffraction surface of the laser light applied to the object surface. Optical sensor for detecting the diffraction direction of light (4) Based on the diffraction direction detected by the optical sensor,
The illumination direction of the subject by the illuminator is controlled such that the direction in which the projected light beam extends when the light beam illuminating the subject is projected on the surface of the subject is perpendicular to the direction in which the groove extends. An illumination direction controller is provided.

[0007]

Embodiments of the present invention will be described below. FIG. 1 is a schematic diagram of a lighting device according to an embodiment of the present invention, and FIG.
FIG. 3 is a view of the optical sensor 13 included in the lighting device shown in FIG. 1 as viewed from the incident direction of light incident on the optical sensor.

The surface of the hard disk 12 is irradiated with laser light from the laser light source 11 shown in FIG. The diffracted light of the laser light applied to the surface of the hard disk 12 is incident on an optical sensor 13 arranged on the diffraction surface of the laser light.
As shown in FIG. 2, the optical sensor 13 has a plurality of light receiving elements 21 arranged in a circular shape for detecting a diffracted light. An opening 22 is provided for reduction. When the diffracted light is incident on the optical sensor 13, a signal indicating which of the light receiving elements 21 of the light receiving elements 21 arranged on the circle is incident is output, and the illumination direction controller shown in FIG. 14 is input.

On the other hand, the illuminator 15 is provided with a plurality of optical fiber bundles. Projecting end 3 of each of these optical fiber bundles
1 are arranged in a circle as shown in FIG. 3, and this illuminator is located at a position facing each other across the center of the circle among the plurality of light emitting ends 31 arranged in the circle. When two light emitting ends are paired, it is configured to switch which of the two light emitting ends constituting the pair emits light. The illumination direction controller 14 controls the light sensor 13
Based on the signal indicating the direction of the diffracted light output from
The direction of light irradiation by the illuminator is controlled so that the hard disk 12 is illuminated in a direction perpendicular to the direction in which the groove 12a on the surface of the hard disk 12 extends. The light applied to the surface of the hard disk 12
The light is reflected by 2 and enters an objective lens arranged in the lens barrel 16. Since the illuminator 15 emits light in a direction perpendicular to the direction in which the groove 12a on the surface of the hard disk 12 extends, light scattered by the groove 12a on the surface strongly enters the lens barrel 16, and The light reflected by the portions other than the grooves has a strong specular reflection component, and therefore only weak light enters the lens barrel 16. Therefore, the CCD line sensor 17 produces an image having a high contrast between the grooves and the non-grooves. It is captured. The image obtained by the CCD line sensor 17 is output to a signal analyzer such as a width measuring device for measuring the width of a groove on the surface of the hard disk 12, for example.

As described above, in the lighting device according to the embodiment of the present invention, the surface of the hard disk 12 is illuminated by irradiating light in a direction perpendicular to the direction in which the groove 12a on the surface of the hard disk 12 extends. The light reflected on the surface of the hard disk 12 and incident on the objective lens strongly carries information on the groove, and even a groove having a small depth or width can be expressed as a strong contrast.

In the above-described embodiment, a hard disk is used as an object. However, the object is not limited to a hard disk, and any object having a groove extending in a predetermined direction on its surface may be used. The groove can be raised using the lighting device of the invention.

[0012]

As described above, the illumination device of the present invention can irradiate light in a direction perpendicular to the direction in which the grooves on the surface of the subject extend, so that the light on the surface of the subject can be obtained.
An image having a sufficient contrast can be obtained even with a groove having a small depth or width.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a lighting device according to an embodiment of the present invention.

FIG. 2 is a view showing a lighting device constituting the lighting device shown in FIG. 1 as viewed from below.

FIG. 3 is a diagram of an optical sensor included in the lighting device shown in FIG. 1 as viewed from an incident direction of light incident on the optical sensor.

FIG. 4 is a schematic view of a microscope to which a lighting device is attached.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 laser light source 12 hard disk 12 a groove 13 optical sensor 14 illumination direction controller 15 illuminator 16 lens barrel 21 light receiving element 22 aperture 31 light emitting end

Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location G02B 21/06 G02B 21/06

Claims (1)

[Claims] 1. An illuminator for illuminating a subject having a groove extending in a predetermined direction on a surface thereof obliquely to the subject surface, a laser light source for irradiating the subject surface with laser light, and the subject. An optical sensor disposed on a diffraction surface of the laser light applied to the surface, for detecting a diffraction direction of the laser light, and a light beam for illuminating the subject based on the diffraction direction detected by the optical sensor. An illumination direction controller for controlling an illumination direction of the subject by the illuminator such that a direction in which a projected light beam extends when projected onto the surface of the subject is perpendicular to a direction in which the groove extends. A lighting device characterized by the above-mentioned.