JPS58116511A - Laser scanner - Google Patents

Abstract

PURPOSE:To increase the number of scanning lines equivalently by varying the focusing position of a hologram lens in such a way that scanning lines on a surface to be scanned at some rotation position of laser luminous flux do not overlap with scanning lines axially symmetrical about the rotation position. CONSTITUTION:Laser luminous flux 12 incident to a hologram 4 arranged on a hologram disk 3 in high-speed rotation is scanned over deflection to form scanning lines as many as hologram lenses 4 on the scanned surface 15 at intervals P as shown by solid lines. Simultaneously, the laser luminous flux 12 is rotated coaxially with the hologram disk 3 at a low speed in the circumferential direction of the disk 3 to rotate the scanning lines. Then, the scanning lines (solid line) on the scanned surface at some rotation positions of the laser luminous flux never overlap with scanning lines (broken line) at positions axially symmetrical to the rotation positions, so the number of scanning lines is doubled equivalently and an actual scanning pattern is obtained by rotating the scanning pattern around a point O, thereby increasing the number of scanning lines equivalently.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laser scanner that focuses and deflects laser light using a hologram lens to scan a surface to be scanned with a light spot.

Fig. 1 is a side view showing the schematic configuration of a conventional laser scanner, in which (1) is a base, (2) is a nine high-speed rotary drive motor supported by the base (1), and (3) is driven by a motor (2). A hologram disk (4) is rotatably driven at a high speed (for example, 5000 rpm) in the direction of the arrow, and a hologram lens (4) condenses and scans the transmitted laser beam formed along the circumference of the hologram disk (3).

(5) is a rotating disk supported on the base (1) coaxially with the rotating shaft of the motor (2), (6) is a rotating disk (5) supported by a belt (
7) through low speed (e.g. 300 rpm) in the direction of the arrow.
), the motor (6), belt (7)
) constitutes a low-speed rotation drive bag k (17). (8) is a first reflecting mirror attached to the axial center of the rotating disk (5);
(9) is attached to the peripheral edge of the rotating disk (5), and the first
The incident laser beam passes through the reflection a(8) of the rotating disk (
5) is a second reflecting mirror that allows the light to enter the hologram disk (3) through the through hole (10) formed in the hole (10), αl) is a laser oscillator, and (a) is a laser beam.

(1 phrase is the condenser lens + (14) is the third reflecting mirror that makes the laser beam (to) enter the center of the rotation axis of the first reflecting mirror (8) + (15) is the scanning surface 1 of the object to be inspected (16) is a focused light spot.

In this conventional laser scanner, a laser oscillator (1
The laser beam (12) emitted from 1) passes through the condensing lens (13), the third reflecting mirror α, the first reflecting mirror (8), and the second reflecting mirror (9) before reaching the hologram disk. (3)
is incident on the hologram lens (4). The hologram disk (3) is rotating at high speed 9, while the rotating disk (5)
) is rotating at a low speed, the hologram disk (3) rotates relatively, and the laser beam (12
) is successively incident on the hologram lens (7) disposed on the circumference of the hologram disk (3), and each time it enters one hologram lens, the light spora) (16) moves on the scanning surface (15). As shown in FIG. 2, one scanning line is formed in the direction of the arrow. At the same time, the rotating disk (5) also rotates, so the scanning trajectory of the optical spora) (16) rotates sequentially, and the optical spora) (16) is
As shown in the example of the scanning line of a book, the scanning surface of the object to be inspected is scanned radially and sequentially rotated through 360 degrees.

However, in the above configuration, if the scanning line on the surface to be scanned at a certain rotational position of the laser beam and the scanning line on the surface to be scanned at an axially symmetrical position overlap with the rotational position, the rotation of the scanning line may cause However, the number of scanning lines could not be greater than the number of hologram lenses.

This invention was made to eliminate the above-mentioned disadvantages of the conventional method, and the scanning line on the surface to be scanned at a certain rotational position of the laser beam and the rotational position are axially symmetrical. An object of the present invention is to provide a laser scanner in which the number of scans N on a surface to be scanned is increased by changing the focusing position of a hologram lens so that the lines do not overlap.

An embodiment of the present invention will be described below with reference to the drawings.

In Figures 4 to 6, the laser beam from the laser oscillator (U) (the chest is a hologram disk (3) rotating at high speed).
The number of hologram lenses (4) is sequentially incident on the hologram lenses (4) arranged on the circumference of the hologram lens (4), and the scanning lines shown in FIG. Form the same number of pieces. At the same time, the rotating disk (5) is rotated by the motor (6), and the hologram lens (4) is rotated.
Laser beam incident on the hologram disk (3)
The scanning line is rotated at low speed coaxially with the hologram disk (3) and in the circumferential direction of the hologram disk (3). In this example,
The scanning line on the scanned surface (15) at a certain rotational position of the laser beam (scanning line indicated by a solid line in FIG. 5) and the scanning line on the scanned surface CL5 at an axially symmetrical position with the rotational position. (scanning lines indicated by broken lines in FIG. 5) do not overlap, and the distance between the scanning lines indicated by solid lines and the scanning lines indicated by broken lines in FIG. The condensing position of the hologram lens (4) is configured to be displaced so that the scan '3/lst closest to the rotation center 0 scans a position offset by T from the rotation center 0.

In this case, when the laser beam rotates and sequentially enters the hologram lens (4) located at A, B, O, D, ~H on the hologram disk (3), the position and direction of a certain scanning line l is a , b, c, d, ~h.

Therefore, one direction (for example, the direction shown in FIG. 5)
, the number of scanning lines is equivalently doubled, so the actual scanning pattern on the scanned surface is the scanning pattern obtained by rotating the scanning pattern in Figure 5 around point O, and the resulting scanning pattern is The number of lines can be increased equivalently.

As described above, according to the present invention, a scanning line is formed on the surface to be scanned by rotating the hologram lens at high speed, and the scanning line is sequentially rotated by rotating the laser beam incident on the hologram lens. In a laser scanner, the hologram lens is focused so that the scanning line on the surface to be scanned at a certain rotational position of the laser beam does not overlap with the scanning line on the surface to be scanned at a position axially symmetrical to the rotational position. Since the position is changed, the number of scanning lines rotating on the surface to be scanned can be equivalently increased.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of this type of device, Fig. 2 is a front view showing the scanning pattern on the scanned surface when the rotation of the laser beam in the conventional example is stopped, and Fig. 3 is a dX2 diagram showing the laser beam. FIG. 4 is a front view showing the state of the scanning pattern when the laser beam rotates, FIG. 4 is a sectional view of a main part of an embodiment of the present invention, and FIG. Scanning on the scanning plane (
FIG. 6 is a front view showing the turn, and FIG. 6 is a front view showing the state of the scanning pattern when the laser beam is rotated in FIG. In the figure, (3) is a hologram disk, (4) is a hologram lens, (to) is a laser beam, and 05) is a surface to be scanned. (17) indicates a low-speed rotary drive device. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Makoto Kuzuno - C Figure 4 Figure 5 Figure 6 56-

Claims (1)

[Claims] A scanning line is formed on the surface to be scanned by rotating a hologram lens at high speed, and the scanning line is sequentially rotated by rotating a laser beam incident on the hologram lens at a low speed. The focusing position of the hologram lens is changed so that the scanning line on the scanning surface at a certain rotational position does not overlap with the scanning line on the scanning surface at an axially symmetrical position. laser scanner.