JPH0312289B2 - - 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.

Conventional technology and problems Conventionally, a holotop with the two functions of optical scanning and reflected signal focusing is shown in Fig. 2 or 3 (in Fig. 2, the same parts as in Fig. 2 are indicated with the same reference numerals). Note that 11 and 12 are mirror surfaces). However, in such a holotop, it is difficult to sustain high speed rotation of 6000 revolutions per minute with a small motor, and the motor
OBJECT OF THE INVENTION The present invention has the drawback that the entire device including the power supply cannot be sufficiently miniaturized.In view of the above-mentioned conventional drawbacks, the present invention miniaturizes the holotop that performs optical scanning and condenses reflected signal light, thereby miniaturizing the entire device. The purpose is to provide a hologram scanner that makes it possible to

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 hologram scanner is a hologram scanner, wherein 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 is superimposed on the hologram in close contact with or separated from the hologram. Another light condensing means is provided, and the signal scattered light that has passed through the hologram and entered the interior of the rotating body is further brought into service by the condensing means and placed on the rotation center axis outside the rotary body. This is achieved by providing a hologram scanner characterized in that it is guided to said photodetector.

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

FIG. 4 is a diagram for explaining the first embodiment of the hologram scanner according to the present invention, in which a is a perspective view of the holotop and b is a sectional view taken along line bb in FIG.

In the same figure, 20 is a phototrop, 21, 22
is a hologram, 23 and 24 are deflection optical elements serving as condensing means, 25 is a rotation axis, 26 is a photodetector, and 27
28 shows a laser beam, 28 shows a scanning light, and 29 shows a reflected signal light.

In this embodiment, a hologram 21 is provided on a holotop 20, which has conventional optical scanning and reflected signal light focusing functions.
Deflection optical elements 23 and 24 are placed in close contact with 22, respectively.
It has been established. Note that the deflection optical elements 23, 2
For example, a hologram or a transmission Fresnel lens is used as the lens 4. In addition, this deflection optical element 2
3 and 24 are provided with groove-shaped windows through which the laser beam 27 passes.

In this embodiment configured as described above, the laser beam 27 is incident on the hologram 21 or 22 and is deflected to become the scanning light 28. The reflected signal light 29 is transmitted to the holograms 21 and 22 and the deflection optical element 2.
3 or 24 and is focused on a photodetector 26 located on the central axis of the rotating shaft 25. In this way, in this embodiment, after the reflected signal light 29 passes through the holograms 21 and 22, it further passes through the deflection optical elements 23 and 24, so the focusing distance can be shortened, and the conventional holotop can be used for focusing. The cylindrical part that was reserved as space can be removed, making the holotop more compact.

FIG. 5 is a diagram for explaining the second embodiment, in which a is a perspective view of the holotop and b is a line bb in figure a.
FIG.

In this figure, the same parts as in FIG. 4 are designated by the same reference numerals. Note that 30 is a specular or reflective Fresnel lens.

This embodiment differs from the previous embodiment in that the phototrop 20 has a mirror surface or a reflective Fresnel lens 3.
0 was attached, and the rotating shaft 25 was brought out from the reflective side. In this case, the reflected signal light 29 passes through the holograms 21 and 22 and the deflection optical elements 23 and 24, is condensed, and is condensed by a mirror or reflective Fresnel lens 3.
0, and the photodetector 2 on the central axis of the rotating shaft 25
The light is focused on 6.

The effects of this embodiment are similar to those of the previous embodiment, but when the deflection optical elements 23 and 24 are Fresnel lenses, the condensing distance is further shortened and the holotop can be further miniaturized.

FIG. 6 is a sectional view for explaining the third embodiment. In this figure, the same parts as in FIG. 4 are designated by the same reference numerals. Note that 30 represents a mirror surface or reflective Fresnel lens, and 31 and 32 represent holograms, respectively.

This embodiment differs from the previous embodiment in that holograms 31 and 32 are incorporated to periodically deflect the laser beam 27 in different directions, and in that two holograms on the left and right sides are separated and superimposed. It is. In addition, holograms 21 to 24 and 31, 32
Each has a different method of creation.

The effects of this embodiment are similar to those of the second embodiment, except that the laser beam 27 is periodically emitted as scanning lights 28, 28'.

Effects of the Invention As described above in detail, the hologram scanner of the present invention is capable of shortening the focusing distance of reflected signal light after it passes through the hologram by superimposing a deflection optical element on the hologram of the phototrop. The cylindrical part of the conventional holotop, which was reserved as a space for condensing light, was removed to achieve a smaller size, which made it possible to downsize the motor, power supply, etc., and further downsize the entire device. If you do this, the effect will be great.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the optical system configuration of a conventional hologram scanner, FIGS. 2 and 3 are diagrams for explaining the holotop, and FIG. 4 is a diagram for explaining the holotop in a hologram scanner according to the present invention. A diagram for explaining the first embodiment, FIG. 5 is a diagram for explaining the first embodiment.
FIG. 6 is a diagram for explaining the third embodiment. In the drawing, 20 is a holotop, 21, 2
2, 31, 32 are holograms, 23, 24 are deflection optical elements, 25 is a rotation axis, 26 is a photodetector, 27
is a laser beam, 28 and 28' are scanning lights, 29 is a reflected signal light, and 30 is a mirror surface or a reflective Fresnel lens.

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 at the laser beam scanning/reading position of the rotating body in an inclined state with respect to the central axis of rotation, and another condensing means is superimposed on the hologram in close contact with or separated from the hologram. is provided, and the signal scattered light that has passed through the hologram and entered the inside of the rotating body is further focused by the condensing means, and the photodetector is installed on the rotation center axis outside the rotating body. A hologram scanner characterized by being guided to. 2. The hologram scanner according to claim 1, wherein the light focusing means is a hologram or a Fresnel lens.