JPH0755638Y2 - Stationary bar code reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a stationary bar code reader which scans a bar code printed on a label or the like with a laser beam and receives the reflected light to read the bar code.

[Conventional technology]

Conventionally, in a stationary bar code reader that scans a beam of laser light on a bar code and reads the reflected light from the bar code, the direction of projection of the laser light is the front direction of the housing of the bar code reader or The reading operation is performed by setting the direction to one of the side directions. As for the barcode reading direction, other than the fixed type, it is known that the barcode reading direction shown in FIG. 2 can be changed. Referring to FIG. 2, a laser light projector 1, a polygon mirror 2,
This is a structure in which the light receiver 3 and the side mirror 7 are attached to the housing 8.

With the above structure, the laser light projector 1 is focused and adjusted so that the laser light beam is minimized on the bar code.
The laser light emitted from the laser light projector 1 is converted into scanning light for bar code reading by the polygon mirror 2. The converted laser light is reflected by the side mirror 7 and projected onto the barcode 4. The bar code 4 reflects scattered light according to the signal line. The reflected light is reflected by the side mirror 7 and input to the light receiver 3. The laser light input to the light receiver 3 is converted into an electric signal.

In the bar code reader of FIG. 2, it is possible to select whether the bar code 4 is read in the front direction or the side direction by changing the mounting angle of the side mirror 7.

However, when the optical path is changed by the side mirror 7, there arises a problem that the distance between the laser light projector and the barcode 4 is changed between the front direction and the side direction by the side mirror 7. Beam focusing of laser light projector is 1c
Since the adjustment is performed in units of m or less, the resolution of reading the signal line of the barcode 4 may be deteriorated. Therefore, it is very inconvenient because the light focusing must be adjusted each time the direction is changed. Further, it is natural that the light becomes weaker as the number of mirrors increases, and further, the influence due to distance cannot be ignored.

[Problems to be solved by the device]

The present invention relates to an improvement for eliminating the need for readjustment due to the change of the light emitting direction. The bar code reading device can easily switch the bar code reading in the front direction or the side direction. It is an object of the present invention to provide a bar code reading device in which the distance between the light projector and the bar code is kept constant even if the direction is changed and the resolution is not changed.

[Means for Solving the Problems]

An optical bench that includes a laser light projector, a polygon mirror that converts the laser light emitted from the laser light projector into a reading and scanning laser light, and a light receiver that receives reflected light from a bar code irradiated by the reading and scanning laser light. The optical bench 10 is mounted as one module on the optical axis 10, and the optical bench 10 is provided with means for rotating the optical axis 10 about the rotation axis by 90 ° from the first setting direction to change the second setting direction. Even if the barcode reading direction is changed to the first or second setting direction, the optical condition for reading the barcode does not change.

〔Example〕

An embodiment of the present invention will be described with reference to the drawings. 1 and 3 are schematic views of the present invention, and FIG. 3 is a view showing that the direction of the laser light projector of FIG. 1 is rotated by 90 °. Although not shown in the figure, a translucent plate is provided so that the laser beam can be emitted and received when the laser beam projector 1 is directed in the first setting direction and the second setting 90 ° direction. The window used is provided.

In the figure, 1 is a laser light projector, 2 is a polygon mirror that converts laser light into scanning light, and 3 is a light receiver that receives reflected light according to the lightness and darkness of the barcode when it is illuminated by the barcode. . These three points are configured and mounted as one module on one optical bench 10. Reference numeral 4 is a bar code whose code can be read.

The above operation will be described. The laser beam emitted by the laser beam projector 1 is transmitted by the polygon mirror 2 at a rate of 30 seconds per second.
It is converted into scanning light of about 0 to 1500 and irradiated on the barcode. The laser light projector 1 is equipped with an adjusting lens for focusing the laser light. This is provided in order to increase the resolution and the light receiving sensitivity of the bar code, and the focus of the laser light projector is adjusted to the position of the bar code 4. A reflected laser beam of high or low intensity corresponding to a code signal enters a light receiver 3 from a bar code 4 which is scanned by projecting a laser beam, and is converted into an electric signal according to the laser reflected light by the light receiver 3 and a decoder (not shown) Sent to.

Next, referring to FIG. 4, this figure is a view of the housing 8 from the lower side. Reference numeral 5 denotes a first optical bench mounting screw, which is screwed into the rotation center 9 of the optical system of the optical bench 10 shown in FIG.
Reference numeral 6 is a second optical bench mounting screw, which is one point of the optical bench 10 that can be set as shown in FIGS. 1 and 3 of the optical bench 10 through a 1/4 circular arc slit 11 provided on the lower surface of the housing 8. It corresponds to the first setting direction shown in FIG. 1 or the second setting direction shown in FIG. FIG. 4 shows the screw position of the casing 8 when the first direction of FIG. 1 is set. In FIG. 3, the 90 ° laser light beam is rotated with respect to the first setting direction in FIG. To change to the second setting direction, loosen the first mounting screw 5 and the second mounting screw 6 of the optical bench 10 with a screwdriver and turn the second mounting screw 6 along the slide 11 to make it 1/4. It is fixed at the other end of the circular arc slit 11. This operation makes the first
The projection direction of the laser light beam in the figure can be changed as shown in FIG. 3, and the setting change operation can be performed as shown in FIGS. 3 to 1. FIG. 5 is a bottom view of the setting state of FIG. 3 seen from below the housing 8.

In addition, regarding a and b described in FIG. 1, a indicates the length from the projector 1 to the exit surface of the laser light reflected by the polygon mirror 2, and b indicates the exit surface. It is the distance to the bar code 4, that is, the distance to the point where the laser beam has the best focusing state on the bar code regardless of the projection angle from the exit surface. The relationship shown in FIG. 1 is the length from the light projector 1 to the exit surface after being reflected by the polygon mirror 2 even in FIG. 3 which is set by changing the 90 ° direction from the laser light projection direction in FIG. Are set to the same.
(Each exit surface is equidistant from the center of the optical bench 10.) Moreover, since the exit surface in the setting direction in FIG. 1 and the exit surface in the setting direction in FIG. The irradiation angles of the laser light with respect to the code are the same. Therefore, in FIG. 1, the best focusing state is obtained at a distance up to the bar code 4, so that the best focusing state is obtained at the same distance b as in FIG. 1 in FIG. Therefore, even if you change the setting of the light emitting direction of the optical bench 10 of the stationary bar code reader installed, it can be viewed from the front even in the front direction.
Even if the side direction is changed by 90 °, it can be read correctly for barcodes that move at the same distance from the light emitting surface.

[Effect of device]

The present invention comprises a laser light projector, a scanning polygon mirror, and a light receiver mounted as one module on an optical bench capable of rotating 90 °, and the direction of laser light projection is rotated 90 ° from the front direction. Even if the distance from the projector to the exit surface of the laser light does not change via the polygon mirror, it is possible to read at the same level if the distance between the exit surface and the barcode is the same in both directions. Since no special technical adjustment is required for changing the direction, the practical effect is large in use.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an optical system structure of a bar code reader according to an embodiment of the present invention. FIG. 2 is a block diagram of a conventional bar code reader. FIG. 3 is a schematic view in which the bar code reading direction of FIG. 1 of the present invention is changed by 90 °. FIG. 4 and FIG. 5 are schematic views showing the mounting condition of the lower surface of the casing according to FIGS. 1 and 3. DESCRIPTION OF SYMBOLS 1 ... Laser light projector, 2 ... Polygon mirror, 3 ... Photo receiver, 4 ... Bar code, 5 ... 1st screw for attaching an optical bench, 6 ... 2nd screw for attaching an optical bench, 7 ... Side mirror, 8 ... Case, 9 ... Center of rotation of optical bench, 10 ... Optical bench, 11 ... Slit.

Claims (1)

[Scope of utility model registration request] 1. A stationary bar code reader using laser light, wherein a laser light projector, a polygon mirror, and a light receiver are arranged on the optical bench so that the bar code can be read. The housing is provided with screw holes to be screwed and mounted at two points apart from each other, and the housing has an insertion hole for inserting a screw into the central screw hole of the optical bench and an insertion hole for other screws of the optical bench. With a circular arc slit that can rotate the optical bench 90 ° around the center screw with the screw loosened, and fix the optical bench with one end of the circular slit, fix the bar in front of the housing. The code can be read and 90 ° from the front when screwed and fixed at the other end of the arcuate slit.
A stationary bar code reader having a structure capable of reading a bar code in a lateral direction.