JPH0312292B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hologram scanner that performs optical scanning using a hologram.

Recently, in order to save labor at registers in supermarkets and the like, barcode reading devices have come into use that read barcodes printed on the exterior of products and input them into computers.
A hologram scanner using a hologram is suitable for the optical scanning section of this barcode reading device, and therefore, this hologram scanner is often used. Such hologram scanners are required to improve their reading rate.

[Conventional technology]

FIG. 5 is a diagram showing the main parts of a conventional hologram scanner. Holograms 2 and 3 are provided on the bottom slope of a hollow top-shaped rotating body 1, and a reflective Fresnel lens 4 is provided on the internal upper surface to form a porogram rotating body (hereinafter referred to as a holotop) 5, and this hologram 5 is connected to a motor. A laser beam 7 is incident from a slit 9 through a mirror 8 while being rotated by a mirror 6.
Scanning light 1 is alternately diffracted by holograms 2 and 3.
Emit 0. Re-imaging light (scattered signal light) 11 from the barcode enters the holograms 2 and 3 and is diffracted, and then is focused by a reflective Fresnel lens 4 onto a photodetector 12, where the barcode is read.

[Problem that the invention seeks to solve]

In the case of the above configuration, the hologram of one inclined surface emits only one type of scanning beam,
There was a problem in that it was difficult to improve the reading rate.

[Means for solving problems]

The present invention provides a hologram scanner that solves the above-mentioned problems, and its means is such that a laser beam incident on the inside of the rotating body is diffracted by a hologram attached to or formed on the rotating body. At the same time as being emitted to the outside, the emitted light functions as a scanning light for the object to be read due to the rotation of the rotating body, and the signal scattered light from the object to be read due to the scanning light is again focused by the hologram. The hologram scanner is a hologram scanner of a type in which the laser beam is scanned and read out by the rotating body, and the hologram is arranged in a tilted state with respect to the central axis of rotation at the laser beam scanning/reading position of the rotating body. The hologram is formed by being divided into a plurality of facets so as to emit a plurality of types of scanning light, and a reflecting mirror for the signal scattered light is attached or formed on the upper end surface inside the rotating body. The signal scattered light focused by the hologram is reflected by the reflecting mirror and passes through the rotating body again, and the photodetector is arranged on the rotation center axis outside the rotating body. This is done by a hologram scanner characterized by being guided to.

[Effect]

The above hologram scanner is one of the holotops.
By dividing a hologram with one inclined surface into a plurality of facets, a plurality of scanning beams can be emitted from the hologram with one inclined surface, thereby improving the reading rate of the hologram scanner.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention as a perspective view.

In this embodiment, the hologram provided on the slope of the holotop 20 is divided into a plurality of (two in the figure) facets 21 and 22, so that multiple types of scanning light are emitted as described below. The other structure is the same as the conventional example explained in FIG.

This embodiment configured in this manner is multifunctional as described below. Figure 2 shows facet 21
A scanning light 23 with a focal length of A is emitted from the facet 22, and a scanning light 23 with a focal length of B is emitted from the facet 22.
Holograms of the facets 21 and 22 can be created so that the scanning light 24 with ≠A) is emitted, thereby increasing the depth of focus of the scanning light. Further, as shown in FIG. 3, the facet 2 is adjusted so as to change the direction of the scanning light 25 emitted from the facet 21 and the scanning light 26 emitted from the facet 22.
It is also possible to create 1 and 22 holograms and change the scanning directions of the plurality of scanning lights. Further, as shown in FIG. 4, holograms of the facets 21 and 22 are created so that the scanning light 27 from the facet 21 scans from a to b, and the scanning light 28 from the facet 22 scans from c to d. It is also possible to scan multiple scanning ranges.

〔Effect of the invention〕

As explained above, according to the present invention, by dividing the hologram on one slope of the holotop into a plurality of facets, for example, the depth of focus of the scanning light can be deepened, the scanning light can be emitted in different directions, and the scanning range can be expanded. It becomes possible to emit different scanning lights, etc., making it possible to make the scanning line multi-functional and improve the reading rate.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of essential parts showing one embodiment of the hologram scanner of the present invention, FIGS. 2 to 4 are diagrams for explaining multifunctionalization of the holotop in the hologram scanner of the present invention, and FIG. The figure is a sectional view of a main part of a conventional hologram scanner. In the figure, 20 is a holotop, 21 and 22 are facets, and 23, 24, 25, 26, 27, and 28 are scanning lights, respectively.

Claims (1)

[Claims] 1. Laser light incident on the rotating body is diffracted by a hologram attached to or formed on the rotating body and emitted to the outside of the rotating body, and the emitted light also reflects the rotation of the rotating body. The hologram scanner functions as a scanning light for the object to be read by the hologram, and the signal scattered light from the object to be read by the scanning light is again focused by the hologram and guided to the photodetector. The hologram is disposed on the rotating body at a laser beam scanning/reading position in an inclined state with respect to the central axis of rotation, and the hologram is arranged on a plurality of facets so as to emit a plurality of types of scanning light. A reflecting mirror for the signal scattered light is mounted or formed on the upper end surface of the rotating body, and the signal scattered light collected by the hologram is reflected by the reflecting mirror. A hologram scanner characterized in that the photodetector is reflected from the rotating body, passes through the rotating body again, and is guided to the photodetector arranged on the rotation center axis outside the rotating body.