JPS6269223A - Beam direction switching device - Google Patents

Abstract

PURPOSE:To prevent the direction precision of a reflected beam from deteriorating owing to an error in the plate thickness of a mirror and to improve productivity by forming step parts of specific height in areas of a mirror holder where mirrors are expected to be arranged, and arranging the mirrors of the same thickness on those respective steps. CONSTITUTION:The step parts of specific height are formed in the areas of the mirror holder where the mirrors are expected to be arranged, and the respective mirrors are equalized in thickness. A laser beam 1 emitted by a laser tube reaches the mirrors 21 having their reflecting surfaces given a difference in height by the steps of the mirror holders 22 and the beam travels as shown by 1a when reflected by the highest reflecting surface firstly. Further, the beam direction is changed in the order of 1a, 1b, and 1c by the same operation as usual. The reflecting surfaces are constituted by arranged the mirrors of the same plate thickness and the mirror holder is manufactured by using a precision casting so the device is constituted at low cost and an error in beam direction after reflection is reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is applicable to the use of laser beams in barcode leagues, etc., in which, for example, a barcode printed on a product is irradiated with a laser beam and the barcode is read using the reflected light. This invention relates to a beam direction switching device.

[Conventional technology]

FIG. 3 is a sectional view showing a conventional beam direction switching device. In the figure, (1) is a laser beam emitted from a laser tube (not shown), and (2) is a mirror that reflects the laser beam (1). , multiple mirrors of different thickness (2m)
, (2b), (2e), (la)
, (lb), (IC) are these mirrors (
2a), (2b), (2e) is the direction of reflection of beam (1). Further, (3) is a mirror holder that holds these mirrors (2a), (2b), and (2c), and (4) is a motor that rotates this mirror holder (3). Note that (5) is the rotation direction of the mirror (2).

Next, the operation will be explained. When the laser beam (1) emitted from the laser tube reaches the mirror (2) (see FIG. 4), which has a step whose reflecting surface height differs depending on the thickness of the mirror, it is reflected and changes its direction. First, when reflected by the thickest mirror (2a), the beam heads in the direction of (1 m). However, this mirror (2) is powered by a motor (
4), after a predetermined time, the beam reflecting surface becomes a mirror (2b), and the beam direction becomes (lb
Switch to l. After a further predetermined period of time, the reflective surface changes to a mirror (
2C), and the beam direction is switched to (IC). Similarly, beam direction 1;t (1c)-(la)→[1
b)-"(le) and repeat the switching sequentially.

[Problem that the invention seeks to solve]

Since the conventional beam direction switching device is configured as described above, it is necessary to use mirrors with different thicknesses, which unavoidably reduces productivity due to an increase in the number of mirror types. Since it is not possible to polish both at the same time, there are problems such as a decrease in accuracy due to deviations in the direction of the reflected beam due to errors in the thickness of the mirror.

This invention has been made to solve the above-mentioned problems, and aims to provide a beam direction switching device that can prevent a decrease in direction accuracy of a reflected beam due to mirror plate FX errors and improve productivity. .

[Means for solving problems]

In the beam direction switching device according to the present invention, a stepped portion of a predetermined height is formed in each mirror arrangement area of a mirror holder, and mirrors of the same thickness are disposed on each of the stepped portions.

[Made by Tsuki]

Since the mirror holder in this invention can be manufactured by M-tight casting, it can be formed with high precision, and there is almost no increase in price due to the addition of steps.Also, since the mirrors only need to be manufactured to the same dimensions, each The mirrors can be polished at the same time, and the occurrence of plate thickness errors is also suppressed.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (9) is a beam reflecting mirror, (2) is a mirror holder that holds and fixes this beam reflecting mirror (2), and (4) is a motor that rotationally drives this mirror holder.

Next, the operation will be explained. The laser beam (1) emitted from the laser tube reaches the mirror (2) whose reflective surface has a height difference due to the step of the mirror holder (2) itself, and is first reflected on the highest reflective surface. Then, the beam heads in the direction (1a). Thereafter, the beam direction is sequentially switched from (la) to (1b) to (1e) in the same manner as in the prior art.

Further, in the above embodiment, the case of beam switching of a barcode reader has been described, but the beam direction switching device of another device using laser light may be used, and the same effects as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, the reflecting surface is constructed by arranging mirrors of the same plate thickness, and the holder for holding the mirror can also be manufactured from precision casting, so the device can be made at low cost, and the beam direction after reflection is This has the effect of obtaining a small error.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the beam switching principle of a beam direction switching device according to an embodiment of the present invention, FIG. 2 is a perspective view of a reflecting surface of the present invention showing the main part of FIG. 1, and FIG. 3 is a conventional FIG. 4 is a cross-sectional view showing the beam direction switching device of FIG. 4, and FIG. 4 is a perspective view of the mirror reflection surface in FIG. (2) is the beam reflection mirror, and (to) is the mirror holder. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (2)

[Claims] (1) By having a mirror holder that is rotationally driven, arranging a plurality of mirrors so that the height of the reflective surface is different in each area divided around the rotation axis, and driving the mirror holder to rotate. In a beam direction switching device that sequentially switches an incident light beam into a plurality of parallel light beams, a stepped portion of a predetermined height is formed in a region of the mirror holder where each of the mirrors is scheduled to be arranged, and each of the mirrors A beam direction switching device characterized by having the same thickness. (2) The beam direction switching device according to claim 1, wherein the mirror holder is made of precision casting.