JPS5820409B2 - Hikari Sousasouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical scanning device that enables scanning of a light beam in a barcode reading device or the like with a simple configuration.

In order to automate the management of product sales, inventory, etc., a method in which a barcode indicating the product type, price, etc. is attached to the product, the barcode is optically read, and the read information is processed by a computer. has been adopted.

In optical barcode reading, the barcode is scanned with a light beam such as a laser beam, and the reflected light is detected by a light receiving element to read the barcode information. To read a barcode, it is necessary to completely scan the barcode from the starting barcode to the ending barcode.

However, the positions of barcodes placed on products are not necessarily aligned in one direction, so the light beam scans in multiple directions until at least one light scanning line is located at the starting point of the barcode. A complete scan must be made from the beginning to the end point.

As conventional means for scanning a light beam in multiple directions, a configuration in which a large number of reflecting mirrors are arranged and vibrated, and a configuration in which a rotating polygon mirror is used are known.

However, in the case of a structure in which the reflecting mirrors are vibrated, a large number of reflecting mirrors must be caused to vibrate in sequence at the correct timing, so the structure becomes complicated and the optical scanning device becomes expensive.

Further, in the case of a configuration using a rotating polygon mirror, there is a drawback that the device becomes large.

An object of the present invention is to enable a light beam to scan in multiple directions with a simple configuration.

Examples will be described in detail below.

FIG. 1 is an explanatory diagram of the principle of the optical scanning device of the present invention, in which a laser light source 1 that outputs a light beam is mechanically or optically driven so that the light beam becomes spiral. .

The light beam passing through the convex lens 2 is projected onto the screen 3, and the screen 3 is scanned by the light beam in a spiral manner.

In addition, in the drawing, the shapes are shown as concentric circles for the sake of simplicity.

If the focal length of the convex lens 2 is f1, the distance from the light source 1 to the convex lens 2 is u1, and the distance from the convex lens 2 to the screen 3 is V, then (1/u)+(1/v)=
By establishing the relationship (1/f)−・−−−−<1), the trajectory 4 of the spiral light beam on the screen 3 (
For the sake of simplicity, they are illustrated as concentric circles as described above.

) can be imaged.

Looking at a part 2a of the periphery that is symmetrical to the center line of the convex lens 2 and excludes the center, the locus of the part 2a on the screen 3 is as shown by 4a.

If this portion 2a is moved toward the center as shown by the dotted line, the locus of the portion 2a after the movement will be as shown by 4b.

That is, the outer portion of the spiral trajectory is a trajectory that moves toward the center.

The bar code corresponding to the position of the screen 3 is scanned by the light beam by utilizing the movement of the light beam trajectory toward the center by the portion 2a.

Figure 2 a shows lens pieces 21 to 2 cut out from a convex lens 2.
4, FIG. 2 is a side view thereof, and FIG. 2c is a perspective view of the lens piece.

Each of the lens pieces 21 to 24 is aligned with the center line Ll of the convex lens 2.

It is symmetrical with respect to L2 and is cut out from the periphery excluding the center.

The lens piece has a shape cut out from the periphery of the convex lens 2, as shown in FIG. 2C.

These lens pieces 21 to 24 are combined to form a deflection section, which is placed at the position of the convex lens 2 in FIG.

Note that the lens piece is cut out along the center line L1. This shows the case where it is parallel to L2, but as described later,
The center line Ll is determined by considering the shape of the lens pieces when they are combined.

Although it is symmetrical with respect to L2, it is also possible to cut it out in a shape that is not parallel to it.

Figures 3a and 3b are front and side views of an example configuration for making the light beam from the light source 1 into a spiral shape, and the light emitting part 11 can be rotated in the vertical direction by the support pin 14 on the inner ring 12. The inner ring 12 is supported by the outer ring 13 using support pins 15 so as to be rotatable in the left-right direction, and the light emitting part 11 is supported so as to be freely movable.

Driving parts 16 and 17 for moving the light emitting part 11 in the vertical and horizontal directions are provided at positions orthogonal to the light emitting part 11. When only the driving part 16 is driven, the light emitting part 11 moves as shown in the dotted line. The light beam 19 moves and becomes inclined with respect to the light beam 18 at the solid line position.

Therefore, the drive unit 16.17 is set to, for example,
t......(3) drive signal X,
If it is driven at Y and the amplitude A is constant, it will draw a circle at an angular velocity ω, and if the amplitude A is varied linearly by Q with respect to time t, it will draw a spiral locus.

Instead of mechanically spiraling the light emitting unit 11 in this way, it is possible to drive the reflecting mirror in the X and Y directions with one drive signal of equations (2) and (3) (this also causes the light beam to spirally move). can be generated.

It is also possible to use a cam mechanism that converts rotational motion into spiral motion.

When the above-mentioned lens pieces 21 and 22 are combined as shown in FIG. 4 to form a deflection section, the trajectory of the light beam can be drawn as shown in FIG. 5.

That is, the deflection section is a combination of a portion of the convex I/lens shown by the dotted line, and the trajectory is a trajectory in which the outside of the spiral trajectory is moved toward the center.

Based on the principle as described above, the lens piece 2 shown in FIG.
1 to 24 are combined as shown in FIG. 6 to form a deflection section.

As a result, as shown in an enlarged view in FIG. 7, the trajectories of the light beam become as shown at 41 to 44 corresponding to the lens pieces 21 to 24, resulting in more or less orthogonal trajectories.

When scanning a barcode using a part of the trajectory of such a light beam, a slit plate 30 can be provided between the deflection section and the barcode corresponding to the screen.

Furthermore, by selecting the shape of the light-transmitting window of the slit plate 30, a desired scanning area can be set.

Note that 25 is a light shielding part provided at the center, which is used to prevent the light beam from the light emitting part 11 along the optical axis from going straight, and to facilitate connection of the lens pieces.

Although the above-mentioned embodiment shows a case in which the deflection section is formed by a lens piece cut out from the convex lens 2, a hologram equivalent to the convex lens 2 can also be used.

A hologram performs the same action as a convex lens due to the refractive index distribution of a plane plate, and the lens pieces 21 to 24 of the hologram are cut out as explained in FIG. 2 and assembled as shown in FIG. 6. A deflection section can also be constructed by this.

Also, each lens piece 21 to 24 is
2 is symmetrical, and lens pieces 23 and 24 are symmetrical, but it is also possible to configure asymmetric lens pieces, that is, to have different cutout sizes, or by cutting out convex lenses with different focal lengths. It is.

It is also possible to configure the deflection section by a combination of the lens piece 21 and the lens piece 23.

In this case, the scanning area will be narrower than that of the deflection section having the configuration shown in FIG. 6, but it may be practical depending on the purpose of use.

As explained above, the present invention provides a light source that outputs a light beam in a spiral shape by mechanical movement of a light emitting part or optical movement by a reflecting mirror, etc., and a convex lens or a hologram equivalent to the convex lens. A plurality of lens pieces cut out from the periphery symmetrically with respect to a line so as not to include the center are integrated while being moved in a direction toward the center, and are placed in the optical path of the light beam from the light source. The spiral light beam can be turned into scanning light with orthogonal trajectories, and the generation of the spiral light beam is mechanically or optically easy, and it can be rotated as in the conventional method. This has the advantage of being a simpler configuration than a configuration in which light beam scanning is performed in multiple directions using a polygonal mirror, a vibrating mirror, or the like.

Therefore, when applied to barcode reading devices and the like, the practical effects are very large.

Further, since the structure of the deflection section can be constructed relatively easily, there is an advantage that the structure is inexpensive.

Note that the light beam may be not only coherent light from a laser light source, but also a light beam obtained by converging light from a light source such as a lamp.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the principle of the present invention, Fig. 2 a ``” - c is a top view for explaining the cutting out of a lens piece from a convex lens,
A side view and a perspective view of a lens piece, FIGS. 3a and 3b are a front view and a side view of an example of a mechanism for generating a spiral light beam, and FIG. 4 is an explanation of a deflection unit that combines two lens pieces. 5 is an explanatory diagram of the trajectory of the light beam by the deflection section shown in FIG. 4, FIG. 6 is an explanatory diagram of the deflection section according to the combination of lens pieces according to the embodiment of the present invention, and FIG. FIG. 3 is an enlarged explanatory diagram of the trajectory of the light beam caused by the deflection unit shown in FIG. 1 is a light source, 2 is a convex lens, 3 is a screen, 4 is a trajectory of a light beam, 21 to 24 are lens pieces, 25 is a light shielding part,
Ll and L2 are the center lines of the convex lens.

Claims (1)

[Claims] 1. A light source that outputs a light beam in a spiral shape, and a plurality of lens pieces cut out from the periphery symmetrically with respect to the center line of a convex lens or a hologram equivalent to the convex lens and not including the center, respectively, at the center. What is claimed is: 1. An optical scanning device comprising: a deflection section that is integrated with the deflection section while being moved in the direction toward which the light beam is directed, and that is disposed in the optical path of the light beam from the light source.