JPH0312296B2 - - 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, barcode reading devices have come into use that read barcodes printed on the exterior of products and input them into computers 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. Furthermore, there has been a demand for miniaturization of the hologram scanner, and a holotop scanner has been devised as an effective means to achieve this goal.

[Conventional technology]

FIG. 3 is a diagram showing the main parts of a conventional holotop type 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 inside the top to form a hologram rotating body (holotop) 5, which is rotated by a motor 6. The scanning light generation laser beam 8 is passed through the laser beam passage hole 7 to the mirror 9 while
The light enters through the holograms 2 and 3 and is alternately diffracted and exits from the scanning hole 10. Further, the scattered signal light 11 from the barcode enters the holograms 2 and 3 and is diffracted, and then is focused on the photodetector 13 by the reflective Fresnel lens 4 and the filter lens 12, and the barcode is read.

[Problem that the invention seeks to solve]

In the structure described above, the motor 6 is located outside the holotop 5, and the laser light source and photodetector are also located outside the holotop, so there is a limit to miniaturization.

[Means for solving problems]

The present invention provides a hologram scanner that solves the above-mentioned problems, and its means is such that a hologram attached to or formed on a rotating body diffracts a laser beam irradiating the hologram from inside the rotating body. At the same time, 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 reflected back to the hologram. This is a hologram scanner of a type in which light is focused and guided to a photodetector, and the hollow rotating body is rotatably attached to a fixed central axis,
One end of the central axis is led out into the rotating body, the hologram is disposed on the rotating body at the laser beam scanning/reading position, and the central axis end inside the rotating body is Lens means for guiding the signal scattered light that has passed through the hologram and entered the interior of the rotating body to the photodetector arranged on the line of the central axis is fixed, and further inside the rotating body, A hologram scanner characterized in that an outer rotor type motor is provided for rotating the body, and includes an outer rotor attached to the rotating body and a stator attached to the end of the rotating shaft. Ru.

[Effect]

The hologram scanner described above has a drive motor built into the holotop that scans the laser beam and focuses the signal beam, so that it can be made much smaller than conventional scanners.

〔Example〕

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

FIG. 1 shows a main part of an embodiment of the present invention as a sectional view. In the figure, 20 is a frame, 21 is a shaft, 22 is a lead wire, 23 is an outer rotor, 2
4 is a holotop, 25 is a bearing, 26 is a stator,
27 is a reflective Fresnel lens which is a lens means;
28 is a laser beam exit hole, 29 is a laser beam, 30 is a laser light source, 31 and 32 are holograms, 33 is a concave lens, 34 is a photodetector, 35 is a scanning light, and 36 is a signal light.

In this embodiment, as shown in FIG.
1 is fixed to a frame 20, a holotop 24 having an outer rotor 23 is rotatably attached to the shaft 21 via a bearing 25, and a stator 26 and a reflective Fresnel lens 27 are fixed to the shaft 21, The reflective Fresnel lens 27 has a laser beam exit hole 28 and a laser light source 30 that emits a laser beam 29 through the hole 28, and the holotop 24 has holograms 31, 32 and a concave lens 33 on its bottom slope. Furthermore, a photodetector 34 is provided on the rotation center axis outside the holotop.

In this embodiment thus constructed, the outer rotor 23 and the stator 26 constitute an outer rotor type motor, and the holotop 24 can be driven to rotate. and a laser beam 2 from a light source 30
The beam 9 is diffracted by the holograms 31 and 32 and becomes a scanning beam 35. Further, the scattered signal light 36 from the barcode is diffracted by the holograms 31 and 32 to become parallel light, and further reflected by the Fresnel lens 27.
The light is focused on a photodetector 34 by a concave lens 33, and the barcode is read.

According to this embodiment, the height can be significantly reduced compared to the conventional one. Further, by providing the laser light source 30 on the reflective Fresnel lens 27 inside the holotop, a space between the frame 20 and the holotop 24 is not required, which is advantageous for miniaturization. Furthermore, since the reflective Fresnel lens 27 is fixed, there is no need for a circular arc-shaped beam passage hole as in the past, and the passage hole can be a small hole, which has the advantage of increasing the effective light focusing area. .

Next, another embodiment of the present invention will be described with reference to FIG. In this figure, the same parts as in FIG. 1 are designated by the same reference numerals.

This embodiment differs from the previous embodiment in that the photodetector 34 is housed inside the holotop, and a mirror (convex mirror, plane mirror, etc.) 37 is used instead of the concave lens 33 to guide the signal hole 36 to the photodetector 34. This is what we have set up.

The operation and effects of this embodiment are the same as those of the previous embodiment, and furthermore, laser beam scanning and signal light detection are performed entirely by the holotop, and the holotop becomes a complete scanner module, so the scanner can be significantly improved. Achieved miniaturization.

〔Effect of the invention〕

As explained above, according to the present invention, the holotop drive motor is built into the holotop, thereby making it possible to downsize the holotop, which is a remarkable effect.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a main part showing one embodiment of a hologram scanner according to the present invention, FIG. 2 is a cross-sectional view of a main part showing another embodiment of the present invention, and FIG. 3 is a main part of a conventional hologram scanner. It is a sectional view for explaining a part. In the figure, 20 is a frame, 21 is a shaft, 22 is a lead wire, 23 is an outer rotor, 24 is a holotop, 25 is a bearing, 26 is a stator, 27 is a reflective Fresnel lens, 30 is a laser light source, 31, 32
indicates a hologram, and 34 indicates a photodetector.

Claims (1)

[Scope of Claims] 1. By a hologram attached to or formed on a rotating body, a laser beam irradiated from inside the rotating body to the hologram is diffracted and emitted to the outside of the rotating body, and the emitted light is The hologram scanner functions as a scanning light for the object to be read by the rotation of a 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 hollow rotating body is rotatably attached to a fixed central axis, and one end of the central axis is led out into the rotating body, and the rotating body is provided with the laser beam. The hologram is disposed at a scanning/reading position, and the end portion of the central axis inside the rotating body is arranged so that the signal scattered light that has passed through the hologram and enters the rotating body is placed on the line of the central axis. A lens means for guiding the photodetector to the photodetector is fixed, and an outer rotor attached to the rotating body and an outer rotor attached to the end of the rotating shaft are further fixed inside the rotating body for rotating the rotating body. A hologram scanner characterized by being provided with an outer rotor type motor consisting of a stator. 2. The hologram scanner according to claim 1, wherein the light source of the laser beam is fixed at a fixed position inside the rotating body. 3. The hologram scanner according to claim 1, wherein the photodetector is fixed to an end of the rotating shaft inside the rotating body.