JPS6374023A - Hologram scanner - Google Patents

Abstract

PURPOSE:To thin a bar-code reader by focusing a scanning light by a hologram lens, and also, deflecting it in plural directions. CONSTITUTION:One piece of holo-window 3 provided with a hologram lens 31, and a laser light scanning mechanism 4 for allowing a scanning light 41 to be made incident on the hologram lens 31 from plural directions are provided. Subsequently, the scanning light 41 is focused by the hologram lens 31, and also, deflected in plural directions. That is to say, a hologram scanner using the holo-window 3 which has unified a fixed hologram provided with the hologram lens 31, and a window cover does not necessitate a space for synthesizing a scanning pattern because a scanning line is superposed already on the holo- window 3. In this way, a distance extending from a read area to the holo- window 3 is shortened remarkably and the hologram scanner can be thinned.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] Conventional hologram scanners require a space of approximately 100+ nm between the hologram and the scanning pattern forming surface, which hinders the reduction in the thickness of the device. Therefore, the hologram scanner is made thinner by allowing scanning light to enter the hologram lens from multiple directions.

[Industrial application field]

The present invention relates to a barcode reading device using a laser beam, and more particularly to a hologram scanner that allows the device to be made thinner.

BACKGROUND ART Hologram scanners that use a hologram in a scanning section are becoming widely used as laser scanners that scan a laser beam in accordance with a desired pattern.

A hologram scanner is an optical scanning device that is configured so that only a hologram performs two functions: the function of a rotating polyhedron in a conventional optical scanning device and the function of a scanning lens. By using this, it has become possible to form complex scanning patterns with a simple optical system, and it has become possible to realize barcode reading devices with a deep reading depth.However, in supermarkets, etc., the devices are installed on tables along with cash registers, etc. However, in many cases, barcodes are read without moving the product in hand, and there is a demand for thinner laser scanners used in barcode reading devices.

[Conventional technology]

Figure 3 is a schematic diagram showing a conventional hologram scanner, Figure 4
The figure is a perspective view showing a conventional fixed hologram.

In FIG. 3, the conventional hologram scanner has a motor 11.
and a hologram disk 1 having a plurality of holograms.
2, a laser beam scanning mechanism 10, a mirror 13,
It consists of a fixed hologram 2, a window cover 15, etc., and scanning light 16 deflected by a hologram disk 12 is incident on the fixed hologram 2 via a mirror 13. The scanning light 16 that has entered the fixed hologram 2 is further deflected and projected onto the barcode 17.

Also, the reflected light from the barcode 17, that is, the signal scattered light 18
As shown by the broken line, the light is propagated through the optical path in the opposite direction to the scanning light 16 and enters the hologram disk 12, and is focused by the hologram disk 12 onto a photodetector (not shown), where the barcode 17 is read.

The signal scattered light 18 enters the fixed hologram 2 in a diverging manner, but since the fixed hologram 2 is close to the barcode 17, it does not spread significantly. Moreover, fixed hologram 2
Since the light is converted into a plane wave and incident on the hologram disk 12, there is an advantage that the light condensing section of the hologram disk 12 can be made smaller.

In such a hologram scanner, the light that scans the surface of the barcode 17 is called a scanning line, and in order to correctly scan the surface regardless of the direction of the barcode 17, the scanning light 16 that has entered the fixed hologram 2 is deflected in multiple directions. A plurality of scanning lines are formed.

That is, as shown in FIG. 4, the fixed hologram 2 has a substrate 21,
Hologram grating 22.23.24 corresponding to the scan line
A scanning pattern including a plurality of scanning lines 220, 230, and 240 is formed in a space away from the fixed hologram 2.

[Problem that the invention seeks to solve]

FIG. 5 is a diagram showing problems in a conventional hologram scanner.

If the reading window formed in the window cover is close to the fixed hologram as shown in Figure 5fa), if the barcode 17 is narrowly assembled, even if it is moved from the top to the bottom of the figure, the Depending on the position where the code 17 passes, it may not be possible to read it. For example, barcode 17 passing through the position indicated by ■
is readable, but barcodes 17 passing through the positions indicated by ■ or ■ become unreadable. Therefore, Figure 5 (
It is necessary to provide a reading window at a position where the scanning lines 220, 230, and 240 intersect as shown in bl. In conventional hologram scanners, the distance from the position where the scanning lines 220, 230, and 240 intersect to the fixed hologram 2 must be at least about 100 mm, which poses a problem in that it impedes the ability to make the hologram scanner thinner.

[Means for solving problems]

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

The same objects are represented by the same symbols throughout the plan.

The above problem arises because a scanning pattern is formed using a plurality of hologram diffraction gratings, and scanning light 41 is made to enter one hollow window 3 equipped with a hologram lens 31 and the hologram lens 31 from a plurality of directions. This problem is solved by the hologram scanner of the present invention, which has a laser beam scanning mechanism 4, which bundles scanning light 41 using a hologram lens 31, and deflects it in a plurality of directions.

[Effect]

From each independently formed hologram diffraction grating,
Unlike traditional hologram scanners that form a continuous scanning pattern, hologram scanners that use a holowind, which integrates a fixed hologram with a hologram lens and a window cover, scan lines that already overlap on the holowind. Therefore, no space is required to synthesize scanning patterns. Therefore, the distance from the reading area to the hollow window can be significantly shortened, and the hologram scanner can be made thinner.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 2 is an explanatory diagram of the operation of the hologram scanner of the present invention.

When a reference beam 32 and an object beam 33 consisting of a spherical wave or a plane wave are irradiated onto a photosensitive material 35 covered by a mask 34 in FIG. As shown in FIG. The laser beam 38 is focused at a predetermined position 39 determined by the laser beam 38.
9 moves to draw a scanning line 40.

When light enters a lens from different positions, it is focused at different positions. For example, a light source 370 disposed at a different position from the light source 36 of the reference light 32 as shown in FIG. 2 (C1)
When the laser beam 380 is irradiated from the source, the laser beam 380 is focused at a predetermined position 390 determined by the respective conditions of the creation light and the reproduction light, and by scanning the laser beam 380, the focal point 390 moves and follows the scanning line 400. draw.

That is, in FIG. 1, any point 4a of the laser beam scanning mechanism 4
The scanning light 41 emitted from the hologram lens 31 and focused by the hologram lens 31 draws a scanning line 42 . Further, the scanning light 41 emitted from another point 4b or 4c of the laser beam scanning mechanism 4 and focused by the hologram lens 31 draws scanning lines 43 and 44, respectively.

In a hologram scanner using such a hollow window, since the scanning lines already overlap on the hollow window,
No space is required to synthesize scanning patterns.

Therefore, the distance from the reading area to the hollow window can be significantly shortened, and the hologram scanner can be made thinner.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a hologram scanner that allows the barcode reading device to be made thinner.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an embodiment of the present invention, Fig. 2 is an explanatory diagram of the operation of the hologram scanner of the present invention, Fig. 3 is a schematic diagram showing a conventional hologram scanner, and Fig. 4 is a schematic diagram showing a conventional fixed hologram. FIG. 5 is a perspective view showing problems in a conventional hologram scanner. In the figure, 3 is a hollow window, 4 is a laser beam scanning mechanism, 4a,
4b and 4c are emission points, 31 is a hologram lens, 32
is a reference beam, 33 is an object beam, 34 is a mask,
35 is a photosensitive material, 36.37.370 is a light source,
38.380 is the laser beam, 39.390 is the focusing point,
40.400 is a scanning line, 41 is a scanning light, 4
2, 43, and 44 represent scanning lines, respectively. Yasii (The point of the sun and moon is the point of the moon)
-, t'jR figure foil 10

Claims (1)

[Claims] A single hollow window (3) equipped with a hologram lens (31), and a laser beam scanning mechanism (4) that allows scanning light (41) to enter the hologram lens (31) from multiple directions.
A hologram scanner characterized in that the scanning light (41) is focused by the hologram lens (31) and deflected in a plurality of directions.