JPH0312288B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a hologram scanner that performs optical scanning using a hologram.

Background of the Technology Recently, barcode reading devices that read barcodes printed on the exterior of products and input them into computers have come into use in order to save labor at registers in supermarkets and the like. 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.

Figure 1 is a diagram for explaining the optical system configuration of a hologram scanner, and 1 shows a hologram 2 on two sides.
and 3 are equipped with a spinning top-shaped hologram rotating body (hereinafter referred to as holotop), 4 is a laser beam, 5,
5' is a reflector, 6 is a window glass, 7 is a window cover,
and indicate scanning light, respectively. In this hologram scanner, by rotating a holotop 1, a laser beam 4 is alternately incident on holograms 2 and 3, and scanning light is alternately emitted from a slit in a window cover 7. Also the second
As shown in the figure, the re-imaging light 8 reflected from the barcode travels in the opposite direction to the scanning light, enters the holograms 2 and 3, is reflected and converged by the reflective Fresnel lens 9 provided in the holotop 1, and is focused on the rotation axis. The light enters the photodetector 10 in the center and the barcode is read.

Prior Art and Problems In the conventional holotop structure, as shown in FIG. 2, since the interior of the holotop is optically manipulated by a reflective Fresnel lens 9, it was not possible to hold the holotop 1 by passing a shaft through it. For this reason, there was a drawback that vibration occurred during rotation, which increased the load on the motor.

OBJECTS OF THE INVENTION In view of the above-mentioned drawbacks of the conventional art, it is an object of the present invention to provide a photogram scanner having a holotop with low vibration during rotation.

Structure of the Invention According to the present invention, the laser beam 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 is functions as a scanning light for the object to be read by the rotation of the rotating body, 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 rotating body is a hologram scanner, and the rotating body has a metal rotating shaft whose upper end is inserted and fixed inside the rotating body, and a laser beam scanning/reading position of the rotating body is tilted with respect to the rotating shaft. The hologram is arranged on the upper end surface of the rotating body, transmits the signal light focused by the hologram, and transmits the transmitted signal light to the outside of the rotating body. This is achieved by providing a hologram scanner characterized by comprising a lens means for guiding the photodetector installed on the central axis of rotation.

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

FIG. 3 is a diagram for explaining the hologram scanner according to the present invention. In the figure, 11 is a holotop, 12 and 13 are holograms, 14 is a transmission type Fresnel lens, 15 is a metal shaft, 16 is a photodetector, 17 is a scanning beam, and 18 is a reimaging light. .

In this embodiment, as shown in FIG.
A metal shaft 15 is inserted into the holotop 11 having a transmission type Fresnel lens 14 and a transmission type Fresnel lens 14.
A photodetector 16 is provided outside the holotop 11 and on the central axis of rotation.

In this embodiment configured as described above, since the Fresnel lens 14 is of a transmission type, the re-imaging light 18 can be focused outside the holotop 11, so the shaft 15 can be passed through the inside of the holotop 11. This makes it possible to firmly hold the holotop 11 by the shaft 15, thereby reducing vibration during rotation. In this embodiment, a hologram may be used instead of the transmission type Fresnel lens 14. In that case, the focal length can be shortened, so the position of the photodetector 16 can be brought closer to the holotop 11, and the space can be reduced. It becomes possible to

FIG. 4 is a diagram for explaining another embodiment, and in each figure, the same parts as in FIG. 3 are denoted by the same reference numerals.

The embodiment shown in FIG.
This is an asymmetric holotop with a step H on the mounting surface, and in this case, the shape is particularly prone to vibration, so this embodiment in which the shaft 15 is inserted is effective in preventing vibration.

In each of the above embodiments, since the re-imaging light does not pass through the holotop, either a solid or hollow holotop structure may be used.

Effects of the Invention As explained in detail above, in the hologram scanner of the present invention, by inserting the rotating shaft of the holotop into the interior of the holotop, it is possible to firmly fix the phototrop to the shaft. This has a great effect in that it is possible to prevent runout during rotation.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the optical system configuration of a conventional hologram scanner, FIG. 2 is a diagram showing its holotop, FIG. 3 is a diagram for explaining the hologram scanner according to the present invention, and FIG. FIG. 3 is a diagram showing another embodiment. In the drawing, 11 is a holotop, 12, 13
is a hologram, 14 is a transmission Fresnel lens, 1
5 is the axis, 16 is the photodetector, 17 is the scanning beam, 1
8 indicates re-imaging light, 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 rotating body has a metal rotating shaft whose upper end is inserted and fixed inside the rotating body, and a laser beam scanning/reading position of the rotating body arranged at an angle with respect to the rotating shaft. The hologram is disposed on the upper end surface of the rotating body, and transmits the signal light focused by the hologram, and the transmitted signal light is placed outside the rotating body on the central axis of rotation. and a lens means for guiding the photodetector to the photodetector. 2. The hologram scanner according to claim 1, wherein the lens means is a transmission type Fresnel lens. 3. The hologram scanner according to claim 1, wherein the lens means is a hologram.