JPH071345B2 - Laser optical scanning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] In a laser beam scanning device including a scanning laser beam generator, a scanning pattern forming unit, and a reading unit, light in the scanning pattern forming unit is changed in an oblique direction and propagated. It is possible and for the purpose of thinning the scanning pattern forming part,
The refracting body in the optical path of the scanning pattern forming portion is formed of a transparent plate having a parallel curved surface, and the ridgeline of the light guiding surface and the light emitting direction are
With respect to the ridgeline and the light emitting direction on the transparent plate in the parallel plane shape,
Bending and refracting along a curved surface with an angle.

[Industrial application field]

The present invention relates to a bar code reader for reading a bar code of a product, and more particularly to a laser beam scanning device that generates a laser beam and scans in a desired scanning direction.

Bar code readers can be connected to computers to collect real-time sales data, etc.
s) Widely used as a terminal. In such an application, a plurality of bar code readers are often installed on a table at various places, and a laser beam scanning device used therefor is required to occupy a small space, particularly a space in the thickness direction, and be inexpensive.

[Conventional technology]

 FIG. 2 is a block diagram showing the principle of the laser beam scanning device.

In the figure, a scanning laser light generator 2 and a scanning pattern forming unit 3 are arranged in a housing 1. The scanning laser light generator 2 includes a laser light source 20, a beam expander 21, and a mirror 2.
2, 23, a perforated lens 25 having a hole 24, a mirror 26, a motor 27, a hologram disk 28, and a photodetector 29. Further, the scanning pattern forming unit 3 includes a plurality of mirrors 31, 32.
It is composed of A reading unit 11 is provided on the upper surface of the housing 1, and a product 12 is passed over the reading unit 11 to read a barcode 13.

The laser light generated by the laser light source 20 is a beam expander.
The laser light having a predetermined diameter is reflected at 21 and is reflected by the mirrors 22 and 23 to pass through the hole 24 of the perforated lens 25, reflected by the mirror 26 and incident on the hologram disk 28 rotated by the motor 27. The laser light incident on the hologram disk 28 is diffracted by the hologram in a predetermined direction, and the scanning laser light C
And enters the scanning pattern forming unit 3. The laser beam C incident on the scanning pattern forming unit 3 is reflected by the mirrors 31 and 32, emitted from the reading unit 11 as a scanning beam A, and irradiates the barcode 13 of the product 12. The rotation of the hologram disk 28 changes the direction of the laser beam C, and the scanning beam A scans along the barcode 13 in response to this.

The barcode 13 receives the scanning beam A and reflects it as scattered light B. The scattered light B reaches the hologram disk 28 through the original optical path, is diffracted there, and then is reflected by the mirror 26 and focused on the photodetector 29 by the perforated lens 25.

However, the laser beam scanning device uses a mirror to form a scanning pattern, and requires a large space for installing the scanning pattern forming unit. Therefore, in the laser beam scanning apparatus which is designed to be compact and thin without the above problems, a refracting body is provided in the scanning pattern forming portion instead of the mirror.

FIG. 4 is a view showing a conventional refracting body, FIG. 3 (a) is a side view, and FIG. 3 (b) is a plan view.

In FIG. 3 (a), the refracting body 4 is formed of a transparent plate having an appropriate refractive index such as a glass plate or an acrylic plate, and has slanted surfaces 44 and
45 are formed.

The refracting body 4 is provided in the optical path of the scanning pattern forming section, and the laser light C from the scanning laser light generating section shown in FIG. 4 is introduced into the refracting body 4. That is, the laser light C from the laser light generator enters the refractor 4 from the slope 44 at an angle equal to or greater than the critical angle on the flat surface 41, and the incident laser light C repeats total reflection on the opposing parallel surfaces 41 or 42. After propagating in the refracting body 4, it exits the refracting body 4 from the slope 45 at the other end.

The optical path length of the laser light C propagating in the refracting body 4 is the mirror.
Although it is not much different from the case where it is reflected by 31 and reaches the mirror 32,
The scanning pattern forming portion can be made significantly thinner than in the above case.

[Problems to be solved by the invention]

However, the laser light propagating in the refracting body 4 having the parallel surfaces 41 and 42 has a property of propagating without changing its direction as shown in FIG. 4 (b). Therefore, in order to synthesize a scanning pattern in an arbitrary direction such as scanning in an oblique direction using such a refracting body, various holograms may be provided in the laser beam introducing section or the leading section of the refracting body 4, or the refracting body 4 may be used. There is a problem that a mirror, a hologram, etc. must be further installed in the optical path of the laser light emitted from the.

[Means for solving problems]

The above-mentioned problem is that in the laser beam scanning device including the scanning laser beam generator, the scanning pattern forming unit and the reading unit according to the present invention, the refracting body provided in the optical path in the scanning pattern forming unit is a transparent plate. , Both sides of the transparent plate are parallel curved surfaces, both end faces are linear and form slopes, one end face is the light introduction face, the other end face is the light lead-out face, the incident scanning beam from the light introduction face Has a structure in which it propagates while repeating total internal reflection and is emitted to the outside from the light-outcoupling surface. Solved by a laser light scanning device characterized by being a bending and refracting body that is bent along a curved surface with a desired angle (Φ, θ) with respect to the ridgeline and the light emission direction of the transparent plate. To be done.

[Action]

The transparent plate as a refracting body in the optical path of the scanning pattern forming portion is a parallel curved surface, and the ridgeline of the straight and inclined end face as the light output surface and the light emission direction from it are the ridgeline and the light of the transparent plate on the parallel plane. It is bent along a curved surface so that the angles are Φ and θ with respect to the emission direction.

Then, by selecting the angles of Φ and θ so as to match the desired light emission direction, the laser light incident from the light introduction surface, which is a linear inclined end surface, is totally reflected inside the curved surface of the transparent plate. Is repeatedly propagated and is emitted in a desired direction from a light guide surface which is a linear and inclined end surface.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In FIGS. 1 (a) and 1 (b), the refracting body 5 is formed of a transparent plate having an appropriate refractive index such as a glass plate or an acrylic plate, and a plate having parallel planes is bent parallel to a curved surface. After forming the curved surfaces 51 and 52, a slope 54 for introducing laser light and a slope 55 for guiding laser light are provided at both ends thereof.

The laser light C is incident on the refracting body 5 from the inclined surface 54 at an angle equal to or greater than the critical angle on the curved surface 51, and the parallel curved surface 51 is opposed thereto.
Alternatively, the direction of the laser light C gradually changes while propagating while repeating the total reflection at 52, and from the slope 55 at the other end to the refracting body 5.
It goes out of.

When forming a bending and refracting body 5 along a curved surface of a plate having parallel planes, an angle formed by the ridgeline of the refracting body 5 before bending and the ridgeline of the refracting body 5 after bending shown in FIG. Producing a scanning pattern in an arbitrary direction only with the refracting body 5 by appropriately selecting an angle θ formed between φ and the emitting direction of the laser light C before being bent and the emitting direction of the laser light C after being bent. You can

As a result, it is possible to reduce the size and thickness of the laser beam scanning device and to reduce the cost.

〔The invention's effect〕

As described above, according to the present invention, it is possible to provide an inexpensive laser light scanning device having a small occupied space, particularly a thickness direction.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention. FIG. 1 (a) is a plan view, FIG. 1 (b) is a side view, and FIG. 2 is a configuration diagram showing the principle of a laser beam scanning device. FIG. 3 is a view showing a conventional refracting body, FIG. 3 (a) is a side view, and FIG. 3 (b) is a plan view. In the figure, 5 is a refracting body, 51 and 52 are parallel curved surfaces, and 54 and 55 are inclined surfaces.

Front page continued (72) Inventor Fumio Yamagishi 1015 Kamiodanaka, Nakahara-ku, Kawasaki, Kanagawa, within Fujitsu Limited

Claims (1)

[Claims] 1. A laser beam scanning device including a scanning laser beam generator, a scanning pattern forming unit, and a reader.
The refraction element provided in the optical path in the scanning pattern forming section is made of a transparent plate, and both sides of the transparent plate are parallel curved surfaces, both end surfaces are linear, and slanted surfaces are formed, and one end surface is light-introduced. The surface, the other end surface, serves as a light guide surface, and the incident scanning beam from the light guide surface propagates while repeatedly undergoing total internal reflection and exits from the light guide surface. The light emitting directions from the ridgeline and the light deriving surface on the emitting surface are respectively at desired angles (Φ, θ) with respect to the ridgeline and the light emitting direction of the transparent plate in the parallel plane state.
A laser beam scanning device comprising: a bent refracting body having a curved surface and a curved surface.