JPS6238415A - Device for scanning laser beam - Google Patents

Abstract

PURPOSE:To make a space for an optical member required for optical transmission compact by totally reflecting a laser beams in a platelike refracting body such as a glass plate to transmit the laser beam. CONSTITUTION:A laser beam (c) radiated from a scanning laser beam generating part is made incident upon the 1st hologram 23. The incident laser beam (c) is diffracted by the 1st hologram 23, repeatedly totally reflected in the refracting body 22 and then reached to the 2nd hologram 24. The laser beam transmitted in the refracting body 22 is diffracted in the vertically upper direction by the hologram 24, radiated to the outside, diffracted again by the 3rd hologram 24 and radiated in the direction of a reading window as shown in an arrow A to form a required scanning pattern. The 1st hologram 23 diffracts the incident laser beam in a direction to diffract the laser beam more than a critical angle for total reflection in the refracting body 22.

Description

[Detailed description of the invention] [Table of contents] - Overview - Field of industrial application - Prior art - Problems to be solved by the invention - Means for solving the problems - Effects - Examples - Effects of the invention [Summary] In a laser beam scanning device having a scanning laser beam generating section consisting of a laser light source, a hologram disk, etc., and a scanning pattern forming section that deflects the laser beam to create a desired scanning pattern, the scanning pattern forming section has a An optical refracting body such as a glass plate is arranged, and the laser beam is propagated by total reflection within the glass plate to create a space (thickness) in the height direction of the optical system.
A laser beam scanning device that reduces

[Industrial application field]

The present invention relates to a laser beam scanning device such as a hologram scanner that reads barcodes of products, for example.

[Conventional technology]

The configuration of a conventional hologram scanner is shown in FIG. A scanning laser beam generating section 20 and a scanning pattern forming section 21 are arranged within the housing 1 . The scanning laser light generating section 20 is
Laser light source 2, beam expander 3, mirrors 4, 5
, a perforated lens 6 having a hole 19, a mirror 7, a motor 8
, a hologram disk 9, and a photodetector 10. The scanning pattern forming section 21 includes a plurality of mirrors 11 to 15.
Consisted of. A reading unit 16 is provided on the top surface of the housing l, and a barcode 18 is read by passing the product 17 over the reading unit 16.

The laser beam generated by the laser light source 2 is made into a laser beam of a predetermined diameter by the beam expander 3, reflected by the mirror 4.5, passes through the hole 19 of the perforated I-nozzle 6, and is reflected by the mirror 7 to be sent to the motor 8. The light is incident on the hologram disk 9, which rotates. The laser light incident on the hologram disk 9 is diffracted in a predetermined direction by the hologram, becomes scanning laser light C, and enters the scanning pattern forming section 21 . The direction of the laser beam C changes as the hologram disk 9 rotates, and a suitable mirror among the mirrors 11 to 15 (
In the illustrated example, mirrors 13 and 15) reflect the laser light, and the laser light is emitted from the reading section 16 as a scanning beam A and irradiates the barcode 18 of the product 17. Barcode 1
8 receives the scanning beam A and reflects it as scattered light B. This scattered light B reaches the hologram 9 through the original optical path, is diffracted there, is reflected by the mirror 7, is focused by the lens 6, and is detected by the photodetector 10.

[Problem that the invention seeks to solve]

Conventional hologram scanners use a large number of mirrors to form scanning patterns, which requires a large installation space for the scanning pattern forming section, which is an obstacle to miniaturization and thinning of scanners.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a light transmission means in which the optical system of a scanning pattern forming section in a laser beam scanning device such as a hologram scanner is made compact.

[Means for solving problems]

In order to achieve this object, the present invention includes a scanning laser generating section and a laser beam scanning pattern forming section, a refracting body is disposed in the scanning pattern forming section, a laser beam is introduced into the refracting body, and a laser beam is introduced into the refracting body. The laser beam is transmitted within the refractor at least once
A light transmitting means is provided for transmitting the laser light by reflecting it from the base.

[For production]

A laser beam is introduced into, for example, a plate-shaped refracting body, and propagates while being repeatedly totally reflected inside.

〔Example〕

The structure of an embodiment of the light transmission means according to the present invention is shown in FIG. A first hologram 23 is provided at one end of a refracting body 22 made of a glass plate, an acrylic plate, or other transparent plate having an appropriate refractive index, and constitutes a light introduction section. A second hologram 24 is provided at the other end of the refractive body 22 and constitutes a front exit section.

A third hologram 25 is arranged above the second hologram 24. Laser light C from a scanning laser light generating section similar to the conventional configuration described above is incident on the first hologram 23. The incident laser beam C is diffracted by the first hologram 23 and is totally reflected within the refracting body 22 to form the second hologram 2.
Reach 4. The laser beam propagated inside the refracting body 22 is diffracted vertically upward by the hologram 24 and emitted to the outside.
The light is diffracted again by the third hologram 25 and emitted toward a reading window (not shown) in the direction of an arrow to form a desired scanning pattern. The first hologram 23 diffracts the incident laser light within the refracting body 22 in a direction that is equal to or larger than the intended field angle a4. Instead of such a first hologram 23, as shown in FIG.
The laser beam introducing portion may be formed as an inclined surface 26, and the laser beam may be refracted in a direction equal to or greater than the critical angle. Also,
Instead of the first hologram 23, as shown in FIG. 2(b), a prism 27 may be arranged to deflect the introduced laser beam C in a direction equal to or greater than the critical angle. The third hologram 25 is omitted and the second hologram 24
The scanning pattern may be formed only by

The scanning pattern forming side is shown in FIG. The laser beam enters the laser beam introduction part of the refracting body 22 while rotating as shown by the arrow E from the emission point F of the scanning laser beam from a hologram disk (not shown), and draws an incident beam locus 28.

Input holograms (first holograms) 233 to 23C are provided in each laser beam introduction section. Each incident hologram 2
Emission holograms (second holograms) 24a to 24e are provided corresponding to holograms 3a to 23C.

The laser light incident on the incident holograms 23a to 23e is
3(a) or (bl) while total reflection inside the refracting body 22.
As shown, the corresponding second holograms 24a-
24e, and from here each output beam trajectory 282~
28e and emits light in the direction of a reading window (not shown) to scan the product. In addition, in FIG. 3 (al, (bl), in order to avoid complication of the drawing, the first hologram 23a
, 23b, 23c and the beam trajectory due to the first holograms 23d, 238 are drawn separately. FIG. 4 shows the top surface of the reading section of a scanner having such a scanning pattern. The reading section 16 of the scanner is a glass plate covered with a cover 29, and the cover 29 is provided with a reading window 30.

Within this reading window 30, the output beam trajectories 28a to 2
Scanning patterns 313 to 31e appear corresponding to 8e.

〔Effect of the invention〕

As explained above, in the light transmission means of the laser beam scanning device according to the present invention, since the laser light is propagated by total reflection inside a plate-shaped refractive body such as a glass plate, the space required for the optical member for light transmission is can be made smaller, the optical system can be made more compact, and the scanning device can be made more compact.

Further, in the embodiment, the second hologram or the third hologram
If a hologram is created using a spherical wave as a reference beam and a plane wave as an object beam, when the scattered light is focused, the scattered light, which is a spherical wave, is reproduced as a plane wave and propagates inside the refractor. Therefore, the light collection area does not expand during propagation (the hologram area required for light collection can be reduced, and the scanner becomes more compact).

[Brief explanation of drawings]

FIG. 1 is a block diagram of a light transmitting means according to the present invention, FIG. 2 is a partial diagram of another example of the light transmitting means according to the present invention, and FIG. 3 is a scanning pattern formation by the light transmitting means according to the present invention. 4 is a top view of a scanner reading section having the scanning pattern of FIG. 3, and FIG. 5 is a configuration diagram of a conventional hologram scanner. 23, 24, 25... Hologram, 22... Refractor, 21... Scanning pattern forming section, 20... Scanning laser beam generating section. Configuration diagram of an embodiment of the present invention Fig. 1 23.24.25 ... Hologram 22... Refractor (Q) (b) Another configuration diagram of the beam introduction part of the optical system according to the present invention Fig. 2 ( a) (b) Explanatory diagram of scanning f-turn formation Fig. 3 24a to 24e... Output hologram 28... Incident beam trajectory 28a to 28e... Top view of output beam trajectory reading section 16... Reading section Two...Cover 3o...Reading windows 31o to 31e...Scanning pattern Configuration diagram of a conventional hologram scanner Fig. 52...Laser light source 18...Bar code

Claims (1)

[Claims] 1. At least a scanning laser beam generating section and a laser beam scanning pattern forming section are provided, and a refracting body is disposed in the scanning pattern forming section, a laser beam is introduced into the refracting body, and a laser beam is introduced into the refracting body. A laser beam scanning device comprising a light transmitting means for totally reflecting the laser beam at least once inside the body and propagating the laser beam. 2. The refracting body is a refracting body having a hologram in the laser beam introduction part for deflecting the introduced laser beam in a direction equal to or greater than a critical angle for total reflection within the refracting body. A laser beam scanning device according to scope 1. 3. The refracting body is a refracting body having a prism in the laser beam introduction part for deflecting the introduced laser beam in a direction equal to or greater than a critical angle for total reflection within the refracting body. A laser beam scanning device according to scope 1. 4. The refracting body is characterized in that the laser beam introducing portion has an inclined surface for deflecting or directing the introduced laser beam in a direction equal to or greater than a critical angle for total reflection within the refracting body. A laser beam scanning device according to claim 1. 5. The laser beam scanning device according to any one of claims 1 to 4, wherein the refracting body is a refracting body having a hologram at a laser tip/exit portion.