U.S. patent number RE36,528 [Application Number 08/410,509] was granted by the patent office on 2000-01-25 for optical scanning head.
This patent grant is currently assigned to Symbol Technologies, Inc.. Invention is credited to Alexander R. Roustaei.
United States Patent |
RE36,528 |
Roustaei |
January 25, 2000 |
Optical scanning head
Abstract
The .[.ornamental.]. design for a bar code Scanner using the
Light Emitting Diode (LED), Optical Scanner assembly and
Charge-Coupled Devices (CCD) capable of reading the barcode symbols
at the variable distance, as shown and described. The optical
passive elements for increasing the depth of field and method of
fabricating the scanning head by mass-production techniques are
also disclosed.
Inventors: |
Roustaei; Alexander R. (La
Jolla, CA) |
Assignee: |
Symbol Technologies, Inc.
(Holtsville, NY)
|
Family
ID: |
25289493 |
Appl.
No.: |
08/410,509 |
Filed: |
March 24, 1995 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
843266 |
Feb 27, 1992 |
05291009 |
Mar 1, 1994 |
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Current U.S.
Class: |
235/472.01;
235/455; 235/462.41; 235/462.42 |
Current CPC
Class: |
G03F
7/705 (20130101); G06K 7/10722 (20130101); G06K
7/10732 (20130101); G06K 7/10742 (20130101); G06K
7/10811 (20130101); G06K 7/1092 (20130101) |
Current International
Class: |
G03F
7/20 (20060101); G06K 7/10 (20060101); G06K
007/10 () |
Field of
Search: |
;235/455,472,462,466,462.41,462.42 ;250/568,227 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
"CCD Bar Code Scanner;" ZB-1000/2000Plus Series, Zebex Industries,
Inc., 1992 Zebex Catalog No. 920802. .
"CCD Bar Code Handy Scanner Model BHS-6000 Series;" Nippondenso
Co., Ltd., Mar. 1992 brochure. .
"Get a Head with Denso's Reading Edge Technology;" ID Systems, Apr.
1987, vol. 7, No. 3. .
"Information Encoding with Two-Dimensional Bar Codes," Theo
Pavlidis, et al., Computer, vol. 25, No. 6, Jun., 1992, pp.
18-28..
|
Primary Examiner: Pitts; Harold I.
Attorney, Agent or Firm: Morgan & Finnegan, L.L.P.
Claims
I claim:
1. A device for scanning and decoding information encoded in an
optical code, said device comprising:
a printed circuit board having a front, a center, and a rear with a
longitudinal centerline bisecting said printed circuit board into a
left side and a right side;
a plurality of LEDs disposed on said printed circuit board near
said front for projecting light outward from said front, a first
portion of said plurality of LEDs disposed on said left side, each
LED of said first portion being directed to emit light at a
non-zero angle .[.so that its light intersects.]. .Iadd.with
respect to .Iaddend.said longitudinal centerline .[.at an angle
different from other LEDs of said first portion.]., and a second
portion disposed on said right side, each LED of said second
portion being directed to emit light at a non-zero angle.[., so
that its light intersects.]. .Iadd.with respect to .Iaddend.said
centerline .[.at an angle different from other LEDs of said second
portion.]. so that a fan of light is emitted which becomes
increasingly broader at greater distances from said plurality of
LEDs;
an optic module disposed at said center of said printed circuit
board for filtering reflected light which is reflected from the
optical code and for focusing said reflected light at a focal
plane;
a CCD detector disposed at said rear of said printed circuit board
substantially at said focal plane, for receiving said reflected
light and generating an electrical signal in response thereto;
a conversion means for converting said electrical signal into a
digital signal corresponding to said .[.bar.]. .Iadd.optical
.Iaddend.code; and
a voltage source for providing a driving voltage to said plurality
of LEDs, said CCD detector and said conversion means.
2. A device as in claim 1 wherein said plurality of LEDs is
disposed in a generally "V"-shaped arrangement.
3. A device as in claim 1 wherein said fan of light is projected to
form a field of view within which said optical code can be
read.
4. A device as in claim 3 wherein said field of view is within the
range of zero to 9 inches.
5. A device as in claim 1 wherein said optic module comprises a
plurality of lenses disposed within a dark room for shielding out
external light.
6. A device as in claim 1 .Iadd.further comprising a window
disposed at said front of said circuit board .Iaddend.wherein said
plurality of LEDs is disposed as close as possible to said
window.
7. A device as in claim 1 wherein said plurality of LEDs comprises
six LEDs with three LEDs disposed on each of said left side and
said right side of said printed circuit board.
8. A device as in claim 5 wherein said plurality of lenses
comprises at least two piano-convex lenses and one bi-convex lens
disposed along a common optical path.
9. A device as in claim 8 wherein said optic module further
comprises at least one optical filter disposed along said common
optical path. .Iadd.
10. In a device for scanning and decoding information encoded in an
optical code, said device comprising a housing having a window
portion with a first width, said housing retaining therein at least
one printed circuit board having a front corresponding to said
window portion, a light source, an optic module for focusing
reflected light which is reflected from the optical code at a focal
plane, and a CCD detector disposed substantially at said focal
plane for receiving said reflected light and generating an
electrical signal in response thereto, each mounted within said
housing, a conversion means for converting said electrical signal
into a digital signal corresponding to said optical code and a
voltage source for providing a driving voltage to said light
source, said CCD detector and said conversion means, wherein said
device has a field of view having a second width greater than the
first width, an improved light source comprising:
a plurality of LEDs disposed near said front of said at least one
printed circuit board, each LED of said plurality being directed to
emit light in a direction different from other LEDs of said
plurality, said plurality of LEDs creating an incident beam of
light which increases in width as a distance from said window
portion increases. .Iaddend..Iadd.11. The improved light source for
a device claimed in claim 10 wherein said each LED emits light
having a wavelength of 660 nm. .Iaddend..Iadd.12. In a device for
scanning and decoding information encoded in an optical code at a
variable distance from the device, the device comprising a housing
having a housing head with a window portion, a center portion and a
rear portion, and a longitudinal centerline bisecting said housing
head into a left side and a right side, said housing head retaining
at least one printed circuit board having a front portion adjacent
said window portion, an optic module for focusing reflected light
which is reflected from said optical code at a focal plane disposed
in said center portion of said housing head and a CCD detector
disposed on said at least one printed circuit board substantially
at said focal plane, for receiving said reflected light and
generating an electrical signal in response thereto, a conversion
means for converting said electrical signal into a digital signal
corresponding to said optical code, and a voltage source for
providing a driving voltage to said plurality of LEDs, said CCD
detector and said conversion means, the improvement comprising:
a plurality of LEDs disposed near said front portion of said at
least one printed circuit board, a first portion of said plurality
of LEDs being disposed in said left side of said housing head and a
second portion of said plurality of LEDs being disposed in said
right side of said housing head, each of said first portion and
said second portion of said plurality of LEDs being directed to
project light outward from said front through said window portion
so that a fan of light is emitted which becomes increasingly broad
at greater distances beyond said window portion. .Iaddend..Iadd.13.
The device claimed in claim 12 wherein said each LED emits light
having a wavelength of 660 nm. .Iaddend..Iadd.14. A device for
scanning and decoding information encoded in an optical code having
a first width, said device comprising:
at least one printed circuit board having a front, a center, a rear
and a longitudinal centerline bisecting said at least one printed
circuit board into a left side and a right side, said front having
a second width smaller than said first width;
a plurality of LEDs disposed on said at least one printed circuit
board near said front for projecting a light outward from said
front, a first portion of said plurality of LEDs being disposed on
said left side and a second portion of said plurality of LEDs being
disposed on said right side, each LED of said first portion and
said second portion of LEDs being directed to emit light at a
non-zero angle with respect to said centerline so that a fan of
light is emitted which has a beam width which increases at greater
distances from said front of said at least one printed circuit
board;
an optic module disposed at said center of said at least one
printed circuit board for focusing reflected light which is
reflected from the optical code at a focal plane;
a CCD detector disposed substantially at said focal plane on said
at least one printed circuit board for receiving said reflected
light and generating an electrical signal in response thereto;
a conversion means for converting said electrical signal into a
digital signal corresponding to said optical code; and
a voltage source for providing a driving voltage to said plurality
of LEDs,
said CCD detector and said conversion means. .Iaddend..Iadd.15. The
device claimed in claim 14 wherein said each LED emits light having
a wavelength of 660 nm. .Iaddend..Iadd.16. The device claimed in
claim 14 further comprising a light-transmissive window disposed
adjacent said front of said at least one printed circuit board in
front of said plurality of LEDs. .Iaddend..Iadd.17. A device for
scanning and decoding information encoded in an optical code having
a first width, said device comprising:
a housing having a second width at a front end at which an incident
beam of light for illuminating said optical code exits said
housing, said second width being smaller than said first width;
at least one printed circuit board retained within said housing and
having a front corresponding to said front end of said housing, a
center, a rear and a longitudinal centerline bisecting said printed
circuit board into a left side and a right side;
a plurality of LEDs disposed near said front of said at least one
printed circuit board for projecting light outward from said front,
a first portion of said plurality of LEDs being disposed on said
left side and a second portion of said plurality of LEDs being
disposed on said right side, each LED of said first portion of LEDs
and said second portion of LEDs being directed to emit light at a
non-zero angle with respect to said centerline so that said
plurality of LEDs emits a diverging incident beam of light beyond
said front end of said housing;
an optic module disposed at said center of said housing for
focusing reflected light which is reflected from the optical code
at a focal plane;
a CCD detector disposed substantially at said focal plane on said
at least one printed circuit board for receiving said reflected
light and generating an electrical signal in response thereto;
a conversion means for converting said electrical signal into a
digital signal corresponding to said optical code; and
a voltage source for providing voltage to said plurality of LEDs,
said CCD detector and said conversion means;
wherein said device is held at a distance from said bar code symbol
and said diverging incident beam of light has a width at least as
wide as said first width at a point at which said diverging
incident beam of light
contacts said optical code. .Iaddend..Iadd.18. The device claimed
in claim 17 wherein said each LED emits light having a wavelength
of 660 nm. .Iaddend..Iadd.19. The device claimed in claim 17
further comprising a light-transmissive window retained within said
front end of said housing in front of said plurality of LEDs.
.Iaddend..Iadd.20. The device claimed in claim 17 further
comprising an indicator lamp disposed on said housing for providing
visual indication of a successful decode by said optical scanner.
.Iaddend..Iadd.21. The device claimed in claim 17 further
comprising a dark room disposed on said at least one printed
circuit board so that said dark room surrounds said optic module
and said CCD detector. .Iaddend..Iadd.22. The device claimed in
claim 12 further comprising a dark room disposed on said at least
one printed circuit board, said dark room surrounding said optic
module and said CCD detector. .Iaddend.
Description
FIELD OF THE INVENTION
The present invention generally relates to scanning system for
reading and/or analyzing bar code symbols, and more particularly,
to a light-weight, easy to integrate, single windowed, bar code
scanning head supportable entirely by a user, system integrator and
manufacturer (who wishes to integrate the scanning head in their
own devices as bar code reading device) throughout the reading of
the symbols.
BACKGROUND OF THE INVENTION
Many industries, including the assembly processing, grocery and
food processing industry, have designated their products with a bar
code symbol consisting of a series of lines and spaces of varying
widths. Different bar code readers and laser scanning systems have
been developed to decode the symbol pattern to a multiple digit
representation for inventory, production-tracking and check-out
purposes.
Modern miniature laser scanners using the laser diode, have
recently been proposed to provide a portable and integrable laser
scanning head for reading the bar code symbols at the variable
distance. Other bar code scanners (called CCD bar code scanner)
using the Light Emitting Diodes (LEDs) source and Charge Coupled
Devices (CCD) have been developed to provide the same facilities at
a reading distance of zero (contact) up to one and half inches away
and for a bar code width no longer than the window or housing
width. The actual CCD bar code scanner does not provide the comfort
of the laser scanner which allows to read the bar code symbols at
the variable distance and greater than the window or housing
width.
SUMMARY OF THE INVENTION
The invention resides, briefly stated, in a scanning head of a
scanning system for reading bar code symbols, at the variable
distance, and greater than the window or housing width, using the
LEDs source, optical passive assembly and charge coupled devices
(CCD).
The Scanning Head module is equipped with a series of a
readily-visible Light Emitting Diodes (LEDs) light source and a
release/start-up mechanism/input, aiming light arrangement through
a window for changing the reading distance and/or the beam line
size of an outgoing LEDs beam scanned across symbols to be read by
the Scanning Head.
The Scanning head for reading barcode symbols includes one window
mounted on the front region of the head and through which either
the incident beam going to the symbol and/or the reflected beam
returning from the symbol, pass the window through and exteriorly
of, and past, the front and intermediate internal body region of
the scanner (head). Optical passive elements for increasing the
dept of field will be in the front of the CCD.
Using different optical assembly lenses to perform a function to
read far-out and close-in (in contact) symbols as well as an
interchangeable component design and an integral window
construction for the head also are disclosed.
The Scanning Head Module includes five regions:
1--front region
2--rear region
3--intermediate region
4--top region
5--bottom region
The scanning head has a predetermined height defined by a pair of
opposing printed board circuits spaced vertically apart of each
other.
The scanning head includes:
a light source means, e.g. Light Emitting Diodes (LEDs), mounted in
different direction to either side of the device within the
scanning head, for generating an incident light beam toward a
reference plane located exteriorly of the scanning module in the
front region and therefore toward a bar code symbol located in the
reference plane.
an optic module means, e.g. a dark room including a lens support
consisting of at least two lenses, is mounted on the intermediate
region, between the rear of the light source LEDs and front of the
sensor CCD, and is operative for directing the reflected light
along a light path away from the reference plane and back toward
the housing.
a sensor means e.g. Charge Coupled Devices (CCD), is mounted in the
rear region and behind of the optic module, for detecting the light
intensity in the reflected beam over a field of view across the bar
code symbol, and for generating an electrical analog signal
indicative of the detected light intensity. Signal convertor
processing means e.g. analog filter and analog to digital
conversion processing circuitry, is also mounted within the
scanning head, for noise elimination and digitalizing the analog
signal to generate therefrom data descriptive of the bar code
symbol.
In accordance with this invention, window means is mounted on the
scanning module or integration housing, and a broad aspect of this
invention, the source light-transmissive window is mounted at the
front region of the scanning head and in the front of the source
light. The window is filtering and positioning the light path of
the incident beam. The reflected beam travels exteriorly of and
pass through the same window, past the front and intermediate
region through the lenses support and the dark room.
Due to the exterior transmission of the incident beam, the field
and the depth of view are substantially independent of the width of
the window or housing, because of the LEDs position, lenses and
filter assembly mounted in the front of the dark room, between the
top and the bottom region. Put another way, the angular distance
and depth of field are considerably improved.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described, by way of example, with
reference to the accompanying drawings, in which:
FIG. 1 is a side sectional view of a scanning head in accordance
with this invention;
FIG. 2 is a partially broken-away, top sectional view as taken
along line B--B of FIG. 1;
FIGS. 3 and 3(b) are front perspective view as taken along line
C--C of FIG. 1, showing the dark room and the optical lenses
support;
FIG. 4 is a top plan sectional view of the optical train;
FIG. 5 is a partially front view of the FIG. 1, showing the front
window;
FIG. 6 is a top plan schematic view of a prior art CCD bar code
scanner reading from zero (contact) up to one and half inches;
FIG 7 is a top plan schematic view of the scanning head of FIG.
1;
FIG. 8A is a perspective of an example of integration of the
scanning head of FIG. 1, by integration of the scanning head in a
housing, made in two parts (half gun-shaped or flat form) and
diagrammatically shows the interconnection of the scanning head to
the remainder of the system;
FIG. 8B is a side sectional view of an example of integration of
the scanning head of FIG. 1;
FIG. 8C is a top sectional view of an example of integration of the
scanning head of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIGS. 1-7 of the drawings, reference numeral 100
generally identifies a scanning head, easy to use and to integrate
in an enclosure or other products for reading, scanning and/or
analyzing bar code symbols throughout thereof. The scanning head
way include the decoder module which decodes a multiple-digit
representation of the bar code symbols such as UPC, EAN, JAN, Code
39, Code 2/5I, Code 2/5, Code 128, Codabar, Plessey, etc.
Referring to FIG. 1, the scanning head 100 includes generally a
window portion 10 holding the printed board portion 1 and portion
2. The printed board portion 3 is mounted between portion 1 and 2,
in the rear region of the scanning head 100. The portion 1 and 2
are spaced apart of each other by a predetermined height
dimension.
A light source means, i.e., six LEDs 4-9. Three LEDs are soldered
in different direction, on each side of the surface of portion 2,
along the longitudinal axis and are operative for generating, each
one, a fraction of the incident light beam.
An optic module means, i.e., three lenses, are mounted inside of a
lens support portion 11. The portion 11 is mounted on the dark room
portion 13, which is located in the front area of the CCD portion
15, located in the rear region, as shows in FIGS. 1 and 2. A bar
code symbol to be read is located in the vicinity of the reference
plane, that is, anywhere within the depth of focus of the incident
beam as described below, and the light reflected from the symbol
constitutes a reflected beam which is reflected along a light path
away from the reference plane and back toward the scanning
head.
As best shown in FIG. 4 the following portion are mounted in a
cylindrical lenses support 11:
a plano-convex lens 20 which is followed with an optic filter
portion 21;
a bi-concave lens 22 which is followed with an diffuser portion
23;
a plano-convex lens 24 which may be followed with a lens cap 25 or
not. If the lens cap portion 25 is not used, the lens 24 may be
fixed by using the glue or any other fixturing method.
The disposition of the LEDs makes that the output LED's beam is
automatically optically aligned with the center of the optic
support 11.
The dark room 13 is a one-piece light-weight part machined or
preferably molded by inexpensive mass-production techniques of a
dimensionally stable material.
The beam generated by emitted from the LEDs 4-9 passes through the
window portion 10. The line size remains approximatively constant
throughout the depth of focus at either side of the tolerance
plane, because of the window's aperture, portion 10.
The scanning means is preferably a high-speed scanner by:
modulating the LED's light, or
modulating the CCD's scanning transfer pulses.
Although only a single narrow line light is shown in the drawing
for illumination from the LED's beam across the symbol along a
predetermination direction (X-axis scanning) lengthwise thereof, it
is understood that the beam generated by the LEDs for illumination
of the symbol along a transverse direction (Y-axis scanning) which
is substantially orthogonal to the predeterminated direction is
automatically generated.
Referring to the FIGS. 1, 2 and 7, the light path of the incident
beam at the front region of the head will generate a line incident
beam through an angular distance A over a field of view across the
bar code symbol located in the vicinity of the reference plane. A
LED-light-transmissive window 19 may be mounted on the front region
and inside of the window 10, or behind the opening 50, formed
therein a front closed scanning head. It is noted that the width
dimension of the light-transmissive window 19 represents a limiting
factor for the width of the incident beam. Hence, as a rule, the
LEDs 4-9 are mounted as close as possible to the light-transmissive
window to optimize the field of view and the incident's beam
power.
As shown in FIG. 7, the field of view of the incident beam is
substantially independent of the width of the printed circuit board
1, 2 or more generally of the integrated body or housing, in fact,
the field of view, i.e., the transverse beam dimension, of the
incident beam will be larger than the width of the window 10. This
is, of course, due to the fact that the LED's incident beam has
been transmitted outside of the front region of the scanning head,
in different directions from each side of the device, within the
scanning head. In this case the width of the LED's incident beam is
four inches at a distance of one inch from the window 10 and
increase to 5 inches at a distance of two and half inches from the
window 10. Hence, the exterior transmission of the LED's incident
beam and reading from a distance of five to nine inches permits the
head of the present invention to have a distance bar code CCD
scanner reader.
A LED light-transmissive window 50 can be mounted on the front
region. The sensor CCD means 15 is operative for detecting the
intensity of the light in the reflected beam coming from the symbol
over a field of view across the same, throughout the lens support
11 and the dark room 13, and generating in electrical analog signal
indicative of the detected light intensity. In order to improve and
increase the zone of coverage of the sensor means, an optic filter
21 and an optic diffuser 24, are placed inside of the cylindrical
lens support 11 and respectively on each side of the bi-concave
lens 22.
The lenses support 11, throughout the dark room, positions the
light path of the reflected beam to the sensor means CCD reference
numeral 15.
All other various electrical sub-circuits diagrammatically
represented by reference numerals 12, 14, 47, 48, 49 are provided
on the board 1. A printed circuit board 3 is mounted within the
printed circuit boards 1 and 2, and some various component and
sub-circuits necessary for the sensor CCD 15 are provided on the
board 3. Signal convertor processing means board 3 is operative to
provide the analog signal generated by the sensor CCD 15 to an
analog-digital convertor to generate therefrom data descriptive of
the barcode symbol. The LEDs 4-9 and other various electrical
sub-circuits related with the LED's scanning control are mounted on
the board 2. The decoder chip may be mounted on board 1 or 2.
The electrical power is supplied to the CCD means 15, by the
appropriate DC-DC convertor mounted aboard the printed board
portion 1 or 2. The power supply component is from 5 volts DC to 14
volts DC.
A coil-type cable 39 (see FIG. 8C), or a serial in line connector
16 (see FIG. 1) may connect the scanning head 100 to the remainder
of the scanning system, which includes a battery-powered decoder
wedge means, e.g. the bar code decoder and the appropriate host
system interfaces module 70 and a host system and/or computer
80.
The cable 17 or 39 includes a plurality of conductive wires which
will carry the power voltage from the module 70 to the scanning
head 100, and all other different control and communication signals
from/to the scanning head 100.
The electrical connections between the connector 28, 29 and the
various components in the scanning head have been omitted from the
drawings for the sake of clarity.
The decoder module 70 may be inside or outside of the scanning head
100 and will process the digitalized signal generated in the
scanning head, and will calculate the desired data, e.g. the
multiple digit representation or code of the bar code symbol, in
accordance with an algorithm contained in a software program. The
decoder module 70 includes a RAM for temporary data storage, an
EPROM or PAL for holding the control program and a microprocessor
which controls the RAM and EPROM or PAL. The decoder module will
also include circuitry for controlling the scanning head and the
communication circuitry for communication with different function
on the scanning head and/or with the host system or host computer
80, such as a hand held terminal, data screen, PC/PS or large data
base, and provides information for the decoded symbol.
A release/start-up mechanism/input 14 is mounted on the top,
intermediate region of the portion 1. By applying a zero volt on
14, the input is operative to turn the microprocessor in the
decoder module on. Upon release of this input, the microprocessor
will turn off after a programmable timeout, if any bar code has not
be detected. This function can also be realized by using the
control line through the connector 16, either a switch button or
keyboard from the host system.
A visual indicator (lamp) 48 output is also mounted on the circuit
board 1. This lamp indicates to the operator or to the user when a
successful decode has been obtained. When a successful decode is
accomplished a programmable beep indicator 12 may indicate to the
operator a beep signal.
The operation of the scanning system is self-evident from the
foregoing, but by way of brief review, the scanning head is
integrated in the other devices or if it is in a half gun-shaped
housing, it will be grasped by its handle portion (see FIG. 8A),
and its barrel is aimed at the bar code symbol to be read. It is
understood that the symbol can be located anywhere in the depth of
field at either side of the reference plane. The movement of the
scanning head from one symbol to the next is facilitated by the low
weight of the scanning head if it is integrated on a handy
device.
To facilitate the explanation of how the scanning head components
disposition's of this invention allows to read from the distance,
the schematic views of FIGS. 6 and 7 have been provided.
FIG. 6 shows a CCD scanner body portion or barrel 81 having a
series of LED light means LEDs 4-9 (a series of six to eight LEDs
is usually used to obtain a LED beam, because of the limited
surface low power illumination of one LED), providing a
perpendicular light, to generate the incident beam, from the
outside of the scanning head's window 10. The reflected beam passes
through the front window 10 to be detected by the sensor means CCD
numeral 15, also described above. The reference plane has to be
close (from zero or contact, up to one and half inches) to the
front of the barrel 81, allowing the sensor CCD means 15 to have
the optimal sensitivity to the reflected beam.
FIG. 7 needs no detailed description, except to repeat that the LED
beam source LEDs 4-9 has its window 10 located in the front region
of the scanning head, behind which each pair of LEDs is mounted in
different directions to either side of the device and provides a
scan angle generating a portion of the incident beam, e.g.:
the LEDs 4-5 operative to generate the extreme corner side of the
incident beam through an angle A=45.degree.;
the LEDs 6-7 operative to generate the corner side of the incident
beam through an angle B=30.degree.;
the LEDs 8-9 operative to generate the middle part of the incident
beam through an angle C=15.degree..
The result of this smart disposition is a uniform visible incident
beam (660 nm) at a very low cost, comparing to the laser diode's
cost.
For the light sensor effectiveness, the closer the front region is
to the reference plane, the more sensitive will be the detection by
the sensor 15.
In operation, because of the limited power illumination of the
LEDs, the user can aim the scanning head at a symbol located,
anywhere from zero (contact) to 6" away from the front of the
barrel 80.
It is understood that in this invention there is any sweeping light
source to generate the incident beam. The incident beam is
generated by fraction illumination issued by the LEDs means
references numeral 4-9.
In accordance with the invention, the housing need only be large
enough to accommodate the components mounted on portion 1, 3,
and/or 2. The scanning head module may be used in different
applications (each scan width requirement may be varied from one to
the next) without making a change in the barrel. By mounting the
scanning head means close or away to the rear of window 10, in
which case the field of view of the incident beam is changed.
The Scanning head module is mountable in flat or half gun-shaped
housing, hand-held heads or any other fixed or portable device and
may be protected from damage due to external shock by shock
mounts.
What is claimed as new and desired to be protected by letters
patent is set forth in the appended claims.
* * * * *