JPH0452730Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a linear light source device used when detecting defects on the surface of an object by optical means.

[Conventional technology]

When detecting defects on the surface of an object by scanning the surface of the object with a beam of light and observing the reflected light, use a light source that has a linear spread in the direction perpendicular to the optical axis direction. is often done. This is because when using a spot-shaped light beam, it is necessary to scan the object surface two-dimensionally, but when using a linear light beam, one-dimensional scanning is performed in a direction perpendicular to both the optical axis direction and the direction in which the light beam spreads. This is because it is sufficient to detect only the defects, and it becomes possible to detect defects efficiently.

Conventionally, when realizing such a linear ray,
Columnar lamps such as fluorescent lamps and halogen lamps have been used, or methods have been used in which a cylindrical lens is used to transform the laser beam into a linear shape.

[Problem that the invention attempts to solve]

However, since the linear light beam obtained as described above has a low light intensity, there is a high possibility that minute defects on the surface of the object to be inspected will be overlooked. Furthermore, the light source device is larger than a normal lamp light source for obtaining a spot-like light beam, and there is a problem in that it is inconvenient to handle.

This idea was made in view of the above points,
The present invention aims to provide a compact linear light source device that can obtain linear light beams with high light intensity.

[Means for solving problems]

A plurality of semiconductor laser devices that emit laser light with a predetermined angular spread in the vertical and horizontal directions are arranged in parallel at a predetermined interval, and a cylindrical lens system is used to control the spread of the laser light in the parallel direction of each semiconductor laser device. However, in the direction perpendicular to the parallel direction, the laser beams are converged so that they become parallel beams. Further, adjustment means is provided for adjusting the arrangement interval of each semiconductor laser device.

[Effect]

Each laser beam converted into a parallel beam through the cylindrical lens system has a spread of a predetermined angle with respect to the parallel direction of each laser device. Therefore, in a region that is more than a predetermined distance away from the laser light source, adjacent laser beams overlap in the parallel direction, and in this region, a laser beam having a cross section linearly extending in the parallel direction is formed as a whole. By selecting a position in this region where the envelope of the light intensity distribution in the parallel direction is flat and placing the object to be inspected at that position, a linear light beam with a uniform light intensity distribution can be transmitted to the object to be inspected. Can irradiate objects. In this case, by adjusting the arrangement interval of each laser device using the adjustment means, the position where the envelope becomes flat can be changed accordingly.

〔Example〕

Hereinafter, one embodiment of this invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1A, the semiconductor laser unit 7 includes a plurality of semiconductor laser devices 1 supported by moving members 2a to 2d and arranged in parallel at equal intervals.
A to 1d are housed in a case 6, and the upper surface of the case 6 is partially cut away in the figure. Each of the laser devices 1a to 1d emits laser light having a predetermined angle of spread (for example, ±15° in the horizontal direction and ±30° in the vertical direction).

As shown in FIG. 1B, the movable members 2a to 2d each have trapezoidal legs 2a1 to 2d1 at their lower portions. Fits into an inverted V-shaped groove-shaped guide rail 6a extending parallel to the parallel direction of the
It can be slid. Thereby, it is possible to move the moving members 2a to 2d laterally along the guide rail 6a.

Further, the moving members 2a to 2d are provided with position adjustment dials 4a to 4 via bearings 3a to 3d, respectively.
d is rotatably mounted. An elongated opening 6b is provided in the upper part of the case 6 in a direction parallel to the rail 6a, and a parallel female thread 5 is provided on the side surface of the opening 6b. Dial 4a-4
d is provided with a male screw that engages with the parallel female screw 5 in each opening 6b, and can be translated in parallel at right angles to the axial direction by turning the head thereof. Along with this, moving members 2a to 2d coupled to dials 4a to 4d
is the guide rail 6 via the legs 2a1 to 2d1.
Laser devices 1a to 1 are moved in parallel in the lateral direction along a and similarly supported by moving members 2a to 2d.
d also moves in parallel by the same distance. Incidentally, a scale is provided on the upper part of the case 6 along the opening 6b to serve as an index during parallel movement.

A converging cylindrical lens 8 is provided in the direction in which laser light is emitted from the semiconductor laser unit 7. This cylindrical lens 8 is
It maintains the spread of the laser beam in the horizontal direction, but serves to converge the laser beam to a predetermined focal point in the vertical direction, as shown in FIG. The vertical light intensity distribution at the focal line position of the laser beam that has passed through the cylindrical lens 8 is shown in FIG. According to the figure, it is clear that the light intensity increases only in a narrow range centered around the focal line position, and the light intensity at other locations is almost equal to zero.

An elongated slit 9 is provided at the focal line position of the converging cylindrical lens 8. The slit 9 serves to pass only a portion of the laser light vertically focused by the lens 8, which has a high light intensity in the vertical direction.

The laser beam passing through the slit 9 enters a parallel beam cylindrical lens 10 provided on the opposite side of the converging cylindrical lens 8. This cylindrical lens 10 maintains the spread of the laser beam in the horizontal direction, but serves to convert the laser beam into a parallel beam in the vertical direction as shown in FIG. The laser unit 7, lens 8, slit 9 and lens 10 are all housed in a light source case 11 as shown in FIG. The light is radiated outward from 11a.

The laser beam obtained as described above is made into a parallel beam in the vertical direction, and the light intensity is increased. In addition, in the horizontal direction, in a region that is more than a predetermined distance away from the laser unit 7, the laser beams from each of the laser devices 1a to 1d are partially overlapped with each other, and the laser beams as a whole extend linearly in the horizontal direction. A laser beam with a cross section can be obtained.

Here, the horizontal light intensity distribution of the laser beams emitted from the plurality of laser devices 1a to 1c arranged at equal intervals is shown in FIGS. The intervals are different between A and B. As is clear from the figure, the envelope of the horizontal light intensity distribution is approximately flat at a location where adjacent laser beams overlap each other by half of their respective horizontal widths. Also, in places where the horizontal light intensity distribution is almost flat,
The distance varies depending on the distance between each laser device 1a to 1c. This corresponds to P ₃ in Figure 4A and P ₂ in Figure 4B.

Therefore, when detecting defects on the surface of an object to be inspected by irradiating the laser beam obtained by the light source device according to this embodiment, the dial 4a
4d to parallelly move the dials 4a to 4d by a predetermined scale, each laser device is adjusted so that the point where the envelope of the horizontal light intensity distribution becomes flat coincides with the position of the object to be inspected. 1a~
Adjust the interval between 1d. In this way, the object will be irradiated with a flat laser beam that has a linear spread in the horizontal direction, has a high light intensity, and is flat. Therefore, by scanning the object one-dimensionally using this linear laser beam, it is possible to perform highly accurate inspection without overlooking even the smallest defects.

Furthermore, since this light source device uses the semiconductor laser devices 1a to 1d as light sources, the device can be miniaturized. Therefore, for example, the light source case 11
If it is configured to be portable, it can be easily attached and detached from any object in the same way as a normal lamp light source.

Note that in this embodiment, each laser device 1a to 1d
Dial 4a~ as a means to change the interval between
4d and parallel female screws 5, etc., but other suitable means may be used. Further, the parallel beam obtained by the lens 10 can be further converged by adding a converging lens to increase the light intensity.

[Effect of idea]

As described above, according to the semiconductor linear light source device according to this invention, the laser beams emitted from each semiconductor laser device are converged in the vertical direction and made into a parallel beam, and in the parallel direction of each laser device, the laser beams are adjacent to each other. Since it is superimposed with the laser beam, a laser beam with a relatively long linear spread and high optical intensity can be obtained. By adjusting the intervals between each laser device while maintaining equal intervals, it is possible to adjust the point where the light intensity of the laser beam is flat to match the position of the object to be inspected. . Therefore, the object to be inspected can be irradiated with a linearly extending laser beam with high light intensity and a flat light intensity distribution, and by scanning the laser beam one-dimensionally, micro defects can be detected. This makes it possible to conduct highly accurate inspections without overlooking any defects.

Further, according to this semiconductor linear light source device, since a semiconductor laser device is used as a light source, it is possible to make the device compact.

Furthermore, when this semiconductor linear light source device is housed in a portable case, it can form an integrated compact light source device, so it can be used for any object in the same way as a normal lamp light source. It becomes possible to easily attach and detach the device.

[Brief explanation of the drawing]

FIG. 1A is a plan view showing an embodiment of a semiconductor linear light source device according to this invention, FIG. 1B is a sectional view taken along line B-B of FIG. 1A, and FIG. 2 is a side view of the same embodiment. , FIG. 3 is a diagram showing the vertical light intensity distribution at the focal line position of the cylindrical lens for converging laser light emitted from the semiconductor laser device in the same example, and FIG. FIG. 3 is a diagram showing horizontal light intensity distributions of laser beams emitted from a plurality of arranged semiconductor laser devices. 1a to 1d... semiconductor laser device, 2a to 2d
...Moving member, 2a1 to 2d1... Legs of moving member, 3a to 3d... Bearing, 4a to 4d...
Position adjustment dial, 5...parallel female screw, 6...
Case, 6a...guide rail, 6b...opening,
7... Semiconductor laser unit, 8... Cylindrical lens for convergence, 9... Slit, 10... Cylindrical lens for parallel beam, 11... Light source case, 11a... Exit window.

Claims (1)

[Claims for Utility Model Registration] A plurality of semiconductor laser devices arranged in parallel at predetermined intervals, each of which emits laser light with a predetermined angular spread in the vertical and horizontal directions, and adjusting the arrangement spacing of each of the semiconductor laser devices. adjusting means for maintaining the spread of the laser light in the parallel direction of the semiconductor laser devices, and converging the laser light so that the laser light becomes a parallel beam in the direction perpendicular to the parallel direction; a cylindrical lens system that causes the parallel beams to partially overlap each other due to the spread in the parallel direction, and the laser beam as a whole has a cross section linearly extending in the parallel direction. A semiconductor linear light source device.