Optical: systems and elements – Single channel simultaneously to or from plural channels – By partial reflection at beam splitting or combining surface
Reexamination Certificate
1998-02-18
2002-10-08
Shafer, Ricky D. (Department: 2872)
Optical: systems and elements
Single channel simultaneously to or from plural channels
By partial reflection at beam splitting or combining surface
C359S669000, C359S710000, C359S837000, C359S839000, C359S900000, C359S204200, C359S210100, C359S211200, C235S454000, C235S462320, C235S462350, C235S462430, C235S470000
Reexamination Certificate
active
06462880
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a bar code reader and, more particularly, to a bar code reader used for a POS (point-of-sale) system which is installed on a counter of a store and is used for reading bar codes attached to goods.
2. Description of the Related Art
In POS systems and in physical distribution systems, so far, it has been a widely accepted practice to exactly calculate and manage goods by reading bar codes. The bar codes are attached to the goods and are read by using a bar code reader.
In such a bar code reader, a ray of light such as laser light is emitted onto the bar code, which is attached to the article by printing or the like method. Thus the bar code reader scans the bar code surface, and the laser light reflected by the bar code is detected to read the bar code.
FIG. 1A
is a diagram illustrating a conventional bar code reader in a perspective manner so that the internal structure can be seen. The bar code reader employs a source of laser light, such as a semiconductor laser, as a source of light. In
FIG. 1A
, reference numeral
201
denotes a laser module constituted by a laser beam source and lenses. Reference numeral
202
is a polygon mirror, which is a polyhedral mirror having a plurality of reflection planes. The polygon mirror
202
is rotated by a motor
207
. The laser beam emitted from the laser module
201
is reflected by a small plane mirror provided at the center of a concave mirror
203
and arrives at the reflection plane of the polygon mirror
202
. The laser beam is reflected by the reflection plane of the polygon mirror
202
. Here, however, since the polygon mirror
202
is rotating, the laser beam is scanned, for example, in the clockwise direction in the drawing.
Reference numeral
204
denotes mirrors for splitting the scanning line and on which is incident the laser beam scanned by the polygon mirror
202
. The laser beam is downwardly reflected by the scanning line-splitting mirrors
204
, upwardly reflected by a bottom mirror
205
of nearly a V-shape, and is emitted through a reading window
206
.
The laser beam emitted from the reading window
206
scans the article that passes over the bar code reader. The laser beam, after having scanned the article, is reflected by the surface of the article to which the bar code is attached, and is caused to be incident on the bar code reader through the reading window
206
.
Light reflected by the bar code of the article and incident on the bar code reader, is reflected by the bottom mirror
205
, scanning line-splitting mirrors
204
and polygon mirror
202
, and is caused to be incident on the concave mirror
203
. The concave mirror
203
focuses the laser beam reflected and diffused by the bar code toward a light detector
208
. The laser beam received by the light detector
208
is decoded by a decoding circuit in the bar code reader and is output to an external unit.
The bar code reader shown in
FIG. 1A
has only one reading window
206
. Such a bar code reader can be installed on an accounting counter in a store in two ways. I.e., the bar code reader is installed so that the reading window
206
is in flush with the surface of the accounting counter, or the bar code reader is so installed that the reading window
206
is nearly vertical to the surface of the accounting counter.
When the bar code reader of
FIG. 1A
is installed on the accounting counter, there is offered only one reading window
206
as described above. When the article is passed over the bar code reader at the accounting counter to read the bar code attached to the article, the bar code is not scanned by the scanning light unless the bar code faces the reading window
206
, and the bar code is otherwise not read out. This is because in conventional bar code readers, a limitation is imposed on the range scanned by the scanning light or on the direction in which the scanning light is emitted.
To solve the above problem, a bar code reader has in recent years been devised having a plurality of reading windows. Such a bar code reader emits the scanning light through the respective reading windows to scan the article having bar code from a plurality of different directions.
FIGS. 1B and 1D
illustrate appearances of bar code readers
210
and
220
in which the above-mentioned countermeasure is taken. These bar code readers
210
and
220
are provided with reading windows (hereinafter referred to as bottom windows)
216
,
226
formed in the bottom surface of the device, and reading windows (hereinafter referred to as side windows)
217
,
227
formed in the side surface erected at an angle nearly vertical to the bottom windows
216
,
226
. Scanning light is emitted from the bottom windows
216
,
226
toward the upper side windows
217
,
227
. On the other hand, scanning light is emitted in nearly the horizontal direction (toward the operator) from the side windows
217
,
227
.
As shown in
FIGS. 1C and 1E
, the difference between the bar code readers
210
and
220
is that the bottom window
216
of the bar code reader
210
has a size of 5 inches×4 inches, whereas the bottom window
226
of the bar code reader
220
is of a trapezoidal shape having a size of 6 inches×6 inches.
As described above, a plurality of reading windows are provided, and the scanning light is emitted in a plurality of directions through the respective reading windows. Therefore, the article
209
passing on the bar code readers
210
,
220
is irradiated with scanning light from a plurality of directions, and the probability for scanning the bar code is enhanced compared with when a bar code reader having only one reading window is used.
FIG. 1F
illustrates a calculation counter (check-out counter)
230
on which the above-mentioned bar code reader
220
is installed. On the check-out counter
230
is installed the bar code reader
220
. The operator P stands at a position facing the side window
227
.
On the upper side of the side window
227
is provided a key board
222
for inputting data related to the goods to which no bar code has been attached. A belt conveyer
233
exists on the upstream side of the check-out counter
230
to carry the goods to the position of the bar code reader
220
. Reference numeral
235
denotes a guide plate for guiding the goods onto the bottom window
226
of the bar code reader
220
.
As the article is carried to the position of the bar code reader
220
and passes by the bar code reader
220
, the bar code is read out irrespective of the direction of the bar code attached to the article. A POS terminal
234
is provided by the side of the operator P, and the calculation processing is executed by the POS terminal
234
.
FIG. 1G
illustrates a bar code readable area of the bar code readers
210
and
220
of
FIGS. 1B and 1D
. Here, the hatched region RP represents the region where the scanning beams emitted from the side windows
217
,
227
and the bottom windows
216
,
226
are focused. In this region bar code is read out even when the bar code is turned in the horizontal direction by 360 degrees. Thus, since the scanning beams are emitted from the two reading windows, the bar code readable area is broadened. Besides, even when the bar code surface does not completely face one reading window, the bar code can be read out.
However, even such bar code readers have problems as described below. In the case of the bar code reader
210
shown in
FIGS. 1B and 1C
, for example, the bottom window
216
has a size of 4 inches×5 inches. Thus, the bar code reader
210
shown in
FIGS. 1B and 1C
has a narrow bottom window
216
, and a pattern (hereinafter referred to as scanning pattern) is constituted by a small number of scanning lines emitted from the bottom window
216
.
In the case of the bar code reader
220
shown in
FIGS. 1D and 1E
, furthermore, the bottom window
226
has a size of 6 inches×6 inches, which is larger than the size of the bottom window
216
of the bar code reader
210
shown in
FIGS. 1B and 1C
. However,
Ichikawa Toshiyuki
Ohkawa Masanori
Watanuki Hiroshi
Yamazaki Kozo
Fujitsu Limited
Shafer Ricky D.
Staas & Halsey , LLP
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